MRI-based morphological evidence of spinal cord tethering predicts curve progression in adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Existing prognostic factors for adolescent idiopathic scoliosis (AIS) patients have focused mainly on curve, maturity, and bone-related factors. Previous studies have shown significant associations between curve severity and morphological evidences of relative shorter spinal cord tethering in AIS, and increased prevalence of abnormal somatosensory cortical-evoked potentials and low-lying cerebellar tonsil in severe AIS. Earlier evidence suggests that there might be neural morphological predictors for curve progression.

PURPOSE

The purpose of this study was to identify any morphological predictors associated with cord tethering, as measured by magnetic resonance imaging (MRI), for curve progression in AIS patients.

STUDY DESIGN/SETTING

This is a prospective cohort study.

PATIENT SAMPLE

A total of 81 female AIS subjects between 10 and 14 years were included, without surgical intervention during the follow-up period.

OUTCOME MEASURES

Magnetic resonance imaging scans of hindbrain and whole spine and areal bone mineral density (BMD) at bilateral femoral necks were performed.

METHODS

All AIS patients were longitudinally followed up starting from initiation of bracing beyond skeletal maturity in 6-month intervals. Clinical and radiographic data were recorded at each clinic visit. Bone mineral density and MRI measurements including ratio of spinal cord to vertebral column length, ratio of anteroposterior (AP) and transverse (TS) diameter of cord, lateral cord space (LCS) ratio, cerebellar tonsil level, and conus medullaris position were obtained at baseline. Only compliant patients with a minimum 2-year follow-up were analyzed. Adolescent idiopathic scoliosis girls were assigned into three groups according to bracing outcome: Group A, nonprogression (curvature increase of less than or equal to 5°); Group B, progression (curvature increase of greater than or equal to 6°); Group C, progression with surgery indication (Cobb angle of greater than or equal to 50° after skeletal maturity despite bracing). The predictors for curve progression were evaluated using univariate analysis and multivariate ordinal regression model.

RESULTS

The average duration of follow-up was 3.4 (range, 2.0-5.6) years. There were 46 girls (57%) in Group A, 19 (23%) in Group B, and 16 (20%) in Group C. No significant intergroup differences were found in spinal cord length, tonsil level, and conus position. Group C had significantly longer vertebral column length, smaller cord-vertebral length ratio, and higher AP/TS cord ratio compared with Group A, whereas LCS ratio in Group C was significantly increased compared with both Group A and Group B. In regression model, five significant independent predictors including cord-vertebral length ratio (odds ratio [OR]: 1.993 [95% confidence interval {CI}: 1.053-3.771], p=.034), LCS ratio (OR: 2.639 [95% CI: 1.128-6.174], p=.025), initial Cobb angle (OR: 1.156 [95% CI: 1.043-1.281], p=.006), menarche age (OR: 1.688 [95% CI: 1.010-2.823], p=.046), and BMD (OR: 2.960 [95% CI: 1.301-6.731], p=.010) and a marginally significant predictor namely AP/TS cord ratio (OR: 1.463 [95% CI: 0.791-2.706], p=.096) were obtained.

CONCLUSIONS

On baseline MRI measurement, cord-vertebral length ratio and LCS ratio are identified as new significant independent predictors for curve progression in AIS, whereas AP/TS cord ratio is suggested as a potential predictor requiring further validations. The earlier MRI parameters can be taken into accounts for prognostication of bracing outcome.

Scoliosis Research Society members attitudes towards physical therapy and physiotherapeutic scoliosis specific exercises for adolescent idiopathic scoliosis

Background

Attitudes regarding non-operative treatment for adolescent idiopathic scoliosis (AIS) may be changing with the publication of BRAiST. Physiotherapeutic Scoliosis Specific Exercises (PSSE) are used to treat AIS, but high-quality evidence is limited. The purpose of this study is to assess the attitudes of members of the Scoliosis Research Society towards PSSE.

Methods

A survey was sent to all SRS members with questions on use of Physical Therapy (PT) and PSSE for AIS.

Results

The majority of the 263 respondents were from North America (175, 67 %), followed by Asia (37, 14 %) and Europe (36, 14 %). The majority of respondents (166, 63 %) prescribed neither PT nor PSSE, 28 (11 %) prescribed both PT and PSSE, 39 (15 %) prescribe PT only and 30 (11 %) prescribe PSSE only. PT was prescribed by 67 respondents, as an adjunct to bracing (39) and in small curves (32); with goals to improve aesthetics (27) and post-operative outcomes (25). Of the 196 who do not prescribe PT, the main reasons were lack of evidence (149) and the perception that PT had no value (112).

PSSE was prescribed by 58 respondents. The most common indication was as an adjunct to bracing (49) or small curves (41); with goals to improve aesthetics (36), prevent curve progression (35) and improve quality of life (31). Of the respondents who do not prescribe PSSE, the main reasons were lack of supporting research (149), a perception that PSSE had no value (108), and lack of access (63). Most respondents state that evidence of efficacy may increase the role of PSSE, with 85 % (223 of 263) favoring funding PSSE studies by the SRS.

Conclusion

The results show that 22 % of the respondents use PSSE for AIS, skepticism remains regarding the benefit of PSSE for AIS. Support for SRS funded research suggests belief that there is potential benefit from PSSE and the best way to assess that potential is through evidence development.

Return to sports after surgery to correct adolescent idiopathic scoliosis: a survey of the Spinal Deformity Study Group

BACKGROUND CONTEXT

There are no guidelines for when surgeons should allow patients to return to sports and athletic activities after spinal fusion for adolescent idiopathic scoliosis (AIS). Current recommendations are based on anecdotal reports and a survey performed more than a decade ago in the era of first/second-generation posterior implants.

PURPOSE

To identify current recommendations for return to sports and athletic activities after surgery for AIS.

STUDY DESIGN/SETTING

Questionnaire-based survey.

PATIENT SAMPLE

Adolescent idiopathic scoliosis after corrective surgery.

OUTCOME MEASURES

Type and time to return to sports.

METHODS

A survey was administered to members of the Spinal Deformity Study Group. The survey consisted of surgeon demographic information, six clinical case scenarios, three different construct types (hooks, pedicle screws, hybrid), and questions regarding the influence of lowest instrumented vertebra (LIV) and postoperative physical therapy.

RESULTS

Twenty-three surgeons completed the survey, and respondents were all experienced expert deformity surgeons. Pedicle screw instrumentation allows earlier return to noncontact and contact sports, with most patients allowed to return to running by 3 months, both noncontact and contact sports by 6 months, and collision sports by 12 months postoperatively. For all construct types, approximately 20% never allow return to collision sports, whereas all surgeons allow eventual return to contact and noncontact sports regardless of construct type. In addition to construct type, we found progressively distal LIV resulted in more surgeons never allowing return to collision sports, with 12% for selective thoracic fusion to T12/L1 versus 33% for posterior spinal fusion to L4. Most respondents also did not recommend formal postoperative physical therapy (78%). Of all surgeons surveyed, there was only one reported instrumentation failure/pullout without neurologic deficit after a patient went snowboarding 2 weeks postoperatively.

CONCLUSIONS

Modern posterior instrumentation allows surgeons to recommend earlier return to sports after fusion for AIS, with the majority allowing running by 3 months, noncontact and contact sports by 6 months, and collision sports by 12 months.

A population-based cohort study of 394,401 children followed for 10 years exhibits sustained effectiveness of scoliosis screening

BACKGROUND CONTEXT

The value of scoliosis screening has been recently shown in a multicenter randomized controlled trial. However, the long-term sustainability of the clinical effectiveness of scoliosis screening as a routine health service remains unknown.

PURPOSE

The aim of this study was to assess the sustainability of the clinical effectiveness of school scoliosis screening.

STUDY DESIGN/SETTING

A large population-based cohort study with a 10-year follow-up was conducted.

PATIENT SAMPLE

A total of 394,401 students who were in the fifth grade during the five academic years from 1995/1996 to 1999/2000 formed five consecutive annual cohorts. The students were eligible for the Hong Kong scoliosis screening program, with their screening history and medical records until their nineteenth birthdays being assessed.

OUTCOME MEASURES

The outcome measures considered in the study were development of adolescent idiopathic scoliosis by the 19 years of age and the Cobb angle.

METHODS

The clinical effectiveness of scoliosis screening was assessed by referral rate for radiographic diagnosis, sensitivity, specificity, and predictive values.

RESULTS

A total of 306,144 students (78%) participated in scoliosis screening, which used a two-tier system. The prevalence of curves of 20° or greater was 1.8% (95% confidence interval [CI], 1.7-1.8%), whereas the referral rate for radiography, the sensitivity, and the positive predictive value (PPV) for curves of 20° or greater were 4.1% (95% CI, 4.0-4.2%), 91% (95% CI, 90-92%), and 40% (95% CI, 39-41%), respectively. Across the five consecutive annual cohorts, the prevalence and sensitivity for curves of 20° or greater increased by 0.23% (95% CI, 0.21-0.25%; p<.001) and 0.76% (95% CI, 0.43-1.04%; p<.001) per year, respectively; however, the PPV was reduced by 1.71% (95% CI, 1.09-2.33%; p<.001) per year.

CONCLUSIONS

This report describes the first large population-based study with a long-term follow-up indicating that a scoliosis screening program can have sustained clinical effectiveness in identifying patients with adolescent idiopathic scoliosis needing clinical observation. As the prevalence of adolescent idiopathic scoliosis increases, scoliosis screening should be continued as a routine health service in schools or by general practitioners if there is no scoliosis screening policy.

Disease severity and treatment in adolescent idiopathic scoliosis: the impact of race and economic status

BACKGROUND CONTEXT

Ethnic disparities have been documented in the incidence and treatment of many diseases. Additionally, race and socioeconomic status (SES) have been shown to affect disease severity and access to care in the recent orthopedic literature.

PURPOSE

To assess the role, if any, that race, SES, and health insurance type play in disease severity and treatment decisions in patients with adolescent idiopathic scoliosis.

STUDY DESIGN

Retrospective chart review.

PATIENT SAMPLE

Pediatric patients seen in a single surgeon's practice over 6 years (2004-2009).

OUTCOME MEASURES

Treatment modality (observation, bracing, or surgery).

METHODS

Data were obtained from 403 patients seen over 6 years (2004-2009). A patient-reported questionnaire was used to collect race, age, family income, and parent marital status data. Race was self-reported as "Asian," "black or African American," "Hispanic or Latino," "white or Caucasian," or "Other." Socioeconomic status was determined using family income and type of health insurance as indicators. Major curve magnitude and prescribed initial treatment (observation, brace, or surgery) were assessed from physician records. An independent sample t test was used to detect differences in curve magnitude of the different racial groups. A Pearson chi-square analysis was used to detect group differences for curves in surgical patients, defined as curves greater than 40°, and their initial treatment.

RESULTS

Patients self-identified with one of the following racial groups: white (N=219), black (N=86), Hispanic (N=44), Asian (N=37), or Other (N=17). Mean curve magnitude was greater in black than in white patients (33° vs. 28°, p<.05). Black patients were more likely to present with curves in the surgical range (34% vs. 24%, p<.05) and were more likely to have surgery as their initial treatment than white patients (34% vs. 19%, p<.05). Black patients had more limited health care plans and lower incomes compared with whites (p<.001). Patients with higher access insurance plans presented at a younger age than patients with more limited access plans, irrespective of race (13.6 vs. 14.1, p<.05). There was no difference in Cobb angle at presentation by income or type of insurance.

CONCLUSIONS

Curve magnitude and percentage of patients with curves in the surgical range were greater in black than in white patients. There was no difference in age on presentation or treatment offered across all racial groups. Black patients were more likely to have surgery as their initial treatment than white patients. While race did have an impact on disease severity in this single surgeon's practice, SES did not.

Toward a better understanding of direct vertebral rotation for AIS surgery: development of a multisegmental biomechanical model and factors affecting correction

BACKGROUND CONTEXT

The direct vertebral rotation (DVR) technique involves vertebral manipulation by the application of force in the transverse plane using a pedicle screw as the anchor point. The biomechanics of this technique has not been well studied, and the applied derotation force may affect cosmetic outcome and potential complications.

PURPOSE

The purpose of the study was to develop an in vitro biomechanical model replicating DVR and examine the effects of screw placement, derotation direction, and segmental versus en bloc rotation on correction.

STUDY DESIGN

This study is based on a cadaveric spine model examining the biomechanics of DVR.

METHODS

Short three vertebral segments were dissected from thoracolumbar cadaveric spines (T5-L4). Each pedicle of the central vertebra received a unicortical, bicortical, or in-out-in screw. Unconstrained biomechanical tests were performed in an axial rotation (medial and lateral directions) mimicking DVR surgery. Nondestructive tests were performed examining peak force and rotational stiffness with/without a contralateral rod. A destructive failure test was performed on each pedicle screw with a contralateral rod connecting via the contralateral pedicle screw. Repeated-measures analysis of variance and post hoc Student t tests were used to detect significance with screw placement and loading direction as main factors.

RESULTS

Without the contralateral rod, the rotation direction was significant (p=.004, medial stiffness more than lateral). With the contralateral rod, in-out-in placement demonstrated lower stiffness than unicortical or bicortical screws (p=.009), and the rotation direction was significant (p=.003, medial stiffness more than lateral). There was no interaction effect between main factors. Peak force with and without a contralateral rod resulted in a similar pattern of significance as stiffness. Destructive failure tests showed that the placement was significant (p<.02) with in-out-in resulting in lower stiffness than unicortical- and bicortical-placed screws. In-out-in (25±6 N) and unicortical (35±16 N) placements resulted in lower peak load (p<.001) than bicortical (48±17 N) screws.

CONCLUSIONS

The biomechanical characteristics of DVR are dependent on the derotation direction and screw placement. Correction for adolescent idiopathic scoliosis can be attempted irrespective of the type of pedicle screw placement, more efficiently if performing derotation maneuvers en bloc on bicortical screws in the medial direction.

The clinical importance of sacral slanting in patients with adolescent idiopathic scoliosis undergoing surgery

BACKGROUND CONTEXT

The phenomenon of sacral slanting has not been assessed in patients with adolescent idiopathic scoliosis (AIS). It could be important in determining distal fusion level.

PURPOSE

The purpose of this study is to clarify sacral slanting and to reveal frequency, character, and clinical importance of sacral slanting in AIS patients who underwent surgery.

STUDY DESIGN/SETTING

Retrospective review of radiographs.

PATIENT SAMPLE

The study included 389 patients who underwent surgery for AIS at a single center.

OUTCOME MEASURES

Slanted angles of sacrum, distal curve types, and postoperative decompensation were assessed in whole spine anteroposterior radiographs.

METHODS

This was a retrospective case series, which included 389 AIS patients who underwent corrective surgeries. The degree of sacral slanting was defined as the angle between the horizontal line and the upper end plate of the sacrum. Distal curves were classified according to the direction of L4 tilt (L4-left type and L4-right type). The frequency, direction, and relationship with curve types were analyzed descriptively. Postoperative changes of sacral slanting were compared by paired t test. Decompensation by distal fusion level and distal curve types was analyzed descriptively. The p value of less than .05 was considered as statistically significant.

RESULTS

The frequency of sacral slanting was 19.5% (76 of 389), 29.6% (115 of 389), and 40.6% (158 of 389) by using criteria of 5°, 4°, and 3°, respectively. The 86.7% showed sacral slanting on the left side. The combination of L4-left type with left-sided sacral slanting was the most frequent (124 of 158, 78.7%). Slanted angles were decreased in some cases after surgery. Decompensation in the coronal plane was observed in 2 of 22 patients (9.1%) with a distal fusion level of L4 but in none of the 70 patients with a distal fusion level of L3.

CONCLUSIONS

Sacral slanting in patients with AIS is a unique and frequently observed finding that has never been researched to date. Most importantly, sacral slanting is a critical consideration in selecting distal fusion level when planning corrective surgery in patients with AIS.

Reliability and validity of inexpensive and easily administered anthropometric clinical evaluation methods of postural asymmetry measurement in adolescent idiopathic scoliosis: a systematic review

PURPOSE

As accurate and reproducible measurements of spinal curvature are crucial in the examination of patients with adolescent idiopathic scoliosis (AIS), this systematic review aims to report on the reliability and validity of a range of inexpensive and easily administered anthropometric methods of postural asymmetry measurement in an AIS population, to inform practice in a clinical setting.

METHODS

A systematic search of health research databases located studies assessing reliability and validity of inexpensive and easily administered anthropometric measures.

RESULTS

Fourteen studies satisfied eligibility criteria. The methodological quality of included studies ranged from low to high. Validity studies were of moderate to high quality. In total, nine clinically applicable, inexpensive and easily administered anthropometric methods were identified, for assessing AIS curvature. All methods demonstrated high to very high inter-observer and intra-observer reliability. Reported criterion validity of the scoliometer and 2D photographs, when compared to Cobb angle assessed from radiographs, ranged from low to very high. iPhone measurements correlated well with scoliometer measurements. 2D photography results had a moderate to high correlation with 3D topography results.

CONCLUSIONS

Overall, strong levels of evidence exist for iPhone and scoliometer measurements, with a high to very high reliability and moderate to very high validity. Moderate levels of evidence exist for scoliometer with mathematical formula and clinical examination with moderate and low validity, respectively. Limited evidence exists for aesthetic tools TRACE and AI and 2D photography. These results indicate there are accurate and reproducible anthropometric measures that are inexpensive and applicable in therapy settings to assess postural asymmetry; however, these only exist for measurement in the transverse plane, despite 3D characteristics of AIS. Further research is required into an inexpensive and easily administered method that can assess postural asymmetry in all anatomical planes.

EOS microdose protocol for the radiological follow-up of adolescent idiopathic scoliosis

PURPOSE

Imaging plays a key role in adolescent idiopathic scoliosis (AIS) to determine the prognosis and accordingly define the best therapeutic strategy to follow. Conventional radiographs with ionizing radiation have been associated with 1-2 % increased lifetime risk of developing cancer in children, and physicians, therefore, need a sensitive but harmless way to explore patients at risk, according to the "as low as reasonably achievable" concept. The EOS system (EOS imaging, Paris, France) is available in routine clinical use since 2007, and allows 3D reconstructions of the trunk in standing position with significant radiation reduction. With recent technical advances, further dose reduction can be obtained, but at the cost of image quality that might alter the reliability of 3D reconstructions. The aim of the present study was to analyze the reproducibility of a "microdose" protocol, and evaluate its use in clinical practice.

METHODS

32 consecutive patients followed for AIS were prospectively included. Biplanar radiographs were obtained with the EOS system according to the new microdose protocol. From the microdose images obtained, three experienced operators performed 3D reconstructions, two times for each subject in a random order (total, 192 reconstructions). The intraoperator repeatability and interoperator reproducibility were evaluated, as recommended by the International Organization for Standardization, for the most clinically relevant 3D radiological parameters.

RESULTS

The identification of the required anatomical landmarks for the "fast spine" reconstruction process was possible in all cases. None of the patients required a second acquisition for 3D analysis. Mean time for reconstruction was 5 ± 2 min. The intraoperator repeatability was better than interoperator reproducibility for all parameters, with values ranging between 3° and 8° for frontal and sagittal spinal parameters, and between 1° and 8° for pelvic measurements. The agreement was very good for all clinical measurements. No correlation was found between the BMI and the reliability of the measurements.

CONCLUSIONS

Because children are notably more sensitive to the carcinogenic effects of ionizing radiation, judicious use of imaging methods and a search for newer technologies remain necessary. Results of the current study show that the new microdose acquisition protocol can be used in clinical practice without altering the quality of the images. Relevant clinical measurements can be made manually, but the landmarks are also visible enough to allow accurate 3D reconstructions (ICC >0.91 for all parameters). The resulting radiation exposure was 5.5 times lower than that received with the prior protocol, corresponding now to a 45-fold reduction compared to conventional radiographs, and can, therefore, almost be considered negligible.

Effects of novel corrective spinal technique on adolescent idiopathic scoliosis as assessed by radiographic imaging

OBJECTIVE

To compare the therapeutic effects of a 3-dimensional corrective spinal technique (CST) and a conventional exercise program (CE) on altered spinal curvature and health related quality-of-life in patients with adolescent idiopathic scoliosis (AIS).

METHODS

Adolescents with idiopathic scoliosis (N=32, 6 males and 26 females) between 10 and 19 years of age (14.34 ± 2.60 years) were recruited and underwent the CST or CE for 60 minutes/day, 2-3 times a week, and an average of total 30 sessions. Diagnostic X-ray imaging technique was used to determine intervention-related changes in the Cobb angle, thoracic kyphosis angle, lumbar lordosis angle, sacral slope, pelvic tilt, pelvic incidence, and vertebral rotation (Nash-Moe method). The Scoliosis Research Society-22 (SRS-22) health related quality-of-life questionnaire was used. Data were analysed using independent t-test, paired t-test, and non-parametric Mann-Whitney U-test at p < 0.05.

RESULTS

CST showed greater improvements in Cobb angle (p=0.003), vertebral rotation (p=0.000), and SRS-22 scores (self-image and treatment satisfaction subscale scores and total score, p=0.026, p=0.039, and p=0.041, respectively) as compared to the controls. There were no significant changes in the other measures between the two groups.

CONCLUSIONS

This is the first clinical trial to investigate the effects of the 3-dimensional CST on spinal curvatures and health related quality-of-life in AIS, providing the important clinical rationale and compelling evidence for the effective management of AIS.

Initial Cobb angle reduction velocity following bracing as a new predictor for curve progression in adolescent idiopathic scoliosis

PURPOSE

The initial correction rate (ICR) has been widely used as a predictor for curve progression in adolescent idiopathic scoliosis (AIS) undergoing bracing treatment. We proposed a new parameter, the initial Cobb angle reduction velocity (ARV), for prediction of curve progression. The purpose of this study was to identify whether the initial ARV was a more effective predictor than ICR for curve progression in AIS patients undergoing brace treatment, and to evaluate the ideal cut-off point of initial ARV for prediction of curve progression.

METHODS

This was a retrospective cohort study on AIS girls receiving standardized bracing treatment regularly followed up every 3-6 months. Standardized SRS criteria for bracing study were utilized in the case selection. The demographic data, maturity status and Cobb angle of each visit were recorded. The initial ARV and ICR were identified. Patients were divided into progressive (≥6°) and non-progressive (<6°) groups based on their final bracing outcome. Differences between two groups were identified and logistic regression analysis was applied to compare the predictive values of initial ARV and ICR for curve progression during bracing treatment.

RESULTS

Seventy-six patients were included in the non-progressive group and 19 in the progressive group. Significant differences between non-progressive and progressive groups were found in terms of initial ARV (12.8 ± 21.4°/year vs -5.4 ± 15.2°/year, P = 0.001) and ICR (12.1 ± 20.7 % vs -5.8 ± 18.0 %, P = 0.001). The logistic regression analysis revealed that age at initial visit (OR 1.742, P = 0.043) and initial ARV (OR 1.057, P = 0.002) had higher predictive values than ICR (P = 0.601) for curve progression in braced AIS girls. The ideal cut-off point of initial ARV was 10°/year (OR 8.959, P = 0.005) for the prediction of curve progression.

CONCLUSIONS

The initial Cobb angle reduction velocity serves as a better predictor for curve progression than initial correction rate in braced AIS patients with follow-up interval of 3-6 months. At the second visit following bracing prescription, those AIS patients with reduction velocity in Cobb angle lower than 10°/year have significantly higher risk of curve progression.

Computerized tomography imaging in adolescent idiopathic scoliosis: prone versus supine

BACKGROUND

The aim of the present study was to assess the degree of apical vertebral rotation values in Adolescent Idiopathic Scoliosis (AIS) that were obtained on CT scans, and to analyze the influence of patient position (supine versus prone) on the degree of rotation.

METHODS

The study included 50 apical vertebra rotation measurements of 34 patients with Type 1A and Type 3C curvature according to the Lenke classification. CT imaging was applied to the patients in supine and prone positions to measure the apical vertebral rotation (AVR). The average AVR angles were measured using the Aaro-Dahlborn method and the results were compared.

RESULTS

No significant differences were found between the vertebral rotation measured in the prone and supine positions for the Lenke 1A subgroup and the Lenke 3C thoracic group (p = 0.848; p = 0.659, respectively). In the Lenke 3C lumbar group, however, the vertebral rotation in the supine position was found to be significantly lesser than that in the prone position (difference -1.40° ± 1.79°, p = 0.007).

CONCLUSION

The assessment of the apical vertebra rotation is crucial in AIS. Even though the vertebral rotation in the supine position was found to be significantly lesser than that in the prone position, CT imaging in a prone position could not be considered clinically more relevant than the CT images in a supine position as there was less than 3° difference.

Comparison of combined anterior-posterior approach versus posterior-only approach in treating adolescent idiopathic scoliosis: a meta-analysis

PURPOSE

Choosing a surgical approach to treat adolescent idiopathic scoliosis (AIS) is still controversial. To compare the effectiveness and safety of combined anterior-posterior approach to posterior-only approach, we conducted a meta-analysis.

METHODS

We searched electronic database for relevant studies that compared anterior-posterior approach with posterior approach in AIS. Then data extraction and quality assessment were conducted. We used RevMan 5.1 for data analysis. A random effects model was used for heterogeneous data, while a fixed effect model was used for homogeneous data.

RESULTS

A total of ten non-randomized controlled studies involving 872 patients were included. There was no significant difference in Cobb angle (95 % CI -0.33 to 4.91, P = 0.09) and percent-predicted FEV1 (95 % CI -6.79 to 4.54, P = 0.70) between the two groups. In subgroup analysis, the kyphosis angle correction was significantly higher than posterior group in severe subgroup (95 % CI 0.72-6.50, P = 0.01), while no significant difference was found in no-restriction subgroup (95 % CI -2.75 to 5.42, P = 0.52). Patients in posterior group obtained a better percent-predicted FVC than those in anterior-posterior group (95 % CI -13.18 to -4.74, P < 0.0001). Significant less complication rate (95 % CI 2.75-17.49, P < 0.0001), blood loss (95 % CI 363.28-658.91, P < 0.00001), operative time (95 % CI 2.65-3.45, P < 0.00001) and length of hospital stay (95 % CI 1.98-22.94, P = 0.02) were found in posterior group.

CONCLUSIONS

Posterior-only approach can achieve similar coronal plane correction and percent-predicted FEV1 compared to combined anterior-posterior approach. The posterior approach even does better in sagittal correction in severe AIS patients. Significantly less complication rate, blood loss, operative time, length of hospital stay and better percent-predicted FVC are also achieved by posterior-only approach. Posterior-only approach seems to be effective and safe in treating AIS for experienced surgeons.

Magnetic resonance imaging investigations of position of conus medullaris in adolescent idiopathic scoliosis as a peripheral neuropathy

Adolescent idiopathic scoliosis (AIS) is a structural 3-dimensional deformity the spine, which is occurring between 10 years of age and skeletal maturity and it mostly affects prepuberbal girls. The etiology of AIS remains unknown and seems should be multifactorial. According to the theories, there could be a shorter spinal cord or a higher location of the conus medullaris and disproportionate growth in neuro-osseous system. This study wants to investigate the position of the conus medullaris in AIS patients with a large curve magnitude in comparison with healthy adolescents. 94 AIS patients consisting of 25 males and 69 females between 11 and 25 years old, based on physical examination and standing posteroanterior roentgenography of the total spine with a Cobb angle more than 40 degrees was chosen. The main curve magnitude of every AIS patient was measured by the Cobb method. Apex of deformity was determined based on SRS definition. Patients' deformity were calcified based on Lenke classification. Magnetic resonance imaging examinations of the total spine were performed in the AIS group, by means of a 1.5-T magnetic resonance imaging system. The position of conus medullaris was defined according to the method by saffiudin et al and was assessed based on the age, sex, type of deformity, severity of deformity, kyphosis, lordosis, flexibility, apical vertebra, stable vertebra. The mean age of patients were 16.34 with 6.77 of conus medullaris position in mean, which was lower one-third of L1. Our study showed no significant correlation between the position of conus medullaris with age, weight, preoperative curve, flexibility, types of deformity based on Lenke classification and degree of kyphosis and lordisis. In conclusion, there is the same mean and the distribution of the conus medullaris locations for AIS patients and normal populations.

Ultrasound-assisted brace casting for adolescent idiopathic scoliosis, IRSSD Best research paper 2014

BACKGROUND

Brace treatment is the most effective non-surgical treatment for AIS. High initial in-brace correction increases successful brace treatment outcomes. The objective of this study was to investigate if real-time ultrasound (US) can aid orthotists in selecting the pad pressure level and location resulting in optimal in-brace correction of the spine.

METHODS

Twenty six AIS subjects participated in this pilot study with 17 (2 M, 15 F) in the control group and 9 (2 M, 7 F) in the intervention group. For the control group, the standard method was used to design their braces. In addition to the standard of care, a medical 3D ultrasound (US) system, a custom pressure measurement system and in-house software were used to select pad placement and pressure levels for the intervention group. The orthotist used a custom standing Providence brace design system to apply pressures against the patient's torso. The applied pad pressures were recorded. A real-time US spinal image was displayed. Cobb angle measurements from the baseline and the assessment scan were performed. The orthotist then decided if an adjustment was needed in terms of altering the pad locations and pressure levels. The procedures may be repeated until the orthotist attained the best simulated in-brace correction configuration to cast the brace.

RESULTS

In the control group, 8 of 17 (47%) subjects needed a total of 16 brace adjustments after initial fabrication requiring a total of 33 in-brace radiographs. For the intervention group, the orthotist tried additional configurations in 7 out of 9 cases (78%). Among these 7 revised cases, 5 showed better stimulated in-brace corrections and were subsequently used to cast the brace. As a result, only 1 subject required a minor adjustment after initial fabrication. The total number of in-brace radiographs in the intervention group was 10.

CONCLUSIONS

The use of the 3D ultrasound system provided a radiation-free method to determine the optimum pressure level and location to obtain the best stimulated in-brace correction during brace casting. The average number of radiographs per subject taken prior to final brace implementation with the interventional group was significantly lower than the control group.

Monitoring for idiopathic scoliosis curve progression using surface topography asymmetry analysis of the torso in adolescents

BACKGROUND CONTEXT

At first visit and each clinical follow-up session, patients with adolescent idiopathic scoliosis (AIS) undergo radiographic examination, from which the Cobb angle is measured. The cumulative exposure to X-ray radiation justifies efforts in developing noninvasive methods for scoliosis monitoring.

PURPOSE

To determine the capability of the three-dimensional markerless surface topography (ST) asymmetry analysis to detect ≥5° progression in the spinal curvature in patients with AIS over 1-year follow-up interval.

STUDY DESIGN/SETTING

Cross-sectional study in a specialized scoliosis clinic.

PATIENT SAMPLE

In this study, baseline and 1-year follow-up full torso ST scans of 100 patients with AIS were analyzed using three-dimensional markerless asymmetry analysis.

OUTCOME MEASURES

Patients with ΔCobb≥5° and ΔCobb<5° were categorized into progression and nonprogression groups, respectively.

METHODS

The ST scan of each full torso was analyzed to calculate the best plane of symmetry by minimizing the distances between the torso and its reflection about the plane of symmetry. Distance between the torso and its reflection was measured and displayed as deviation color maps. The difference of ST measurements between two successive acquisitions was used to determine if the scoliosis has progressed at least 5° or not. The classification tree technique was implemented using the local deformity of the torso in the thoracic-thoracolumbar (T-TL) and lumbar (L) regions to categorize curves into progression and nonprogression groups. The change in maximum deviation and root mean square of the deviations in the torso were the parameters effective in capturing the curve progression. Funding for this research is provided by the Scoliosis Research Society, and Women and Children's Health Research Institute.

RESULTS

The classification model detected 85.7% of the progression and 71.6% of the nonprogression cases. The resulting false-negative rate of 4% for T-TL curves, representing the proportion of undetected progressions, confirmed that the technique shows promise to monitor the progression of T-TL scoliosis curves. Although 100% L curves with progression were detected using the deviation color maps of the torsos, because of the small number of analyzed L curves, further research is needed before the efficiency of the method in capturing the L curves with progression is confirmed.

CONCLUSIONS

Using the developed classification tree for the patients analyzed in this study, 43% of nonprogression cases between two visits would not have to undergo an X-ray examination.

Quality of life in normal and idiopathic scoliosis adolescents before diagnosis: reference values and discriminative validity of the SRS-22. A cross-sectional study of 1,205 pupils

BACKGROUND CONTEXT

The Scoliosis Research Society 22 Questionnaire (SRS-22) has shown to worsen with increasing deformity in adolescents with idiopathic scoliosis (AIS). However, all the studies have been performed on patients who have already been diagnosed and in relatively small samples.

PURPOSE

The purposes of this study were to evaluate a large sample of consecutive patients before diagnosis to develop reference values and check the discriminative validity and correlation with deformity of the SRS-22.

STUDY DESIGN/SETTING

This is a cross-sectional study, with patients referred to a specialized outpatient scoliosis rehabilitation institute.

PATIENT SAMPLE

The recruited subjects were 1,205 consecutive adolescents, 75% females (13.7±1.9 years), before their first scoliosis evaluation. Five subgroups were 0°-10° Cobb (normal) and 11° to 20°, 21° to 30°, 31° to 40°, and greater than 40° (AIS).

OUTCOME MEASURES

The outcome measure is based on the SRS-22.

METHODS

The SRS-22 was used to examine the differences between the domains of the five subgroups and total scores, and it was correlated with Cobb degrees and curve location. We used one-way analysis of variance and Spearman rho test.

RESULTS

Apart from the self-image domain in both genders and all subgroups, all other scores were greater than 4 points with small standard deviations. Females showed significant differences among groups for all domains and total score (p<.05). In males, function, pain, and mental health did not show statistically significant differences among groups (p>.1). All differences found were less than the minimally clinically significant change (0.5 points). The correlations with the severity of deformity measures were very low (rs<0.289).

CONCLUSIONS

According to our results, deformity is apparently not a real issue for AIS before diagnosis made, treatment planned, and/or specialists interfere with their everyday life. Scoliosis Research Society 22 Questionnaire demonstrated some discriminative validity between small and large curves, but the differences found were small.

Evaluation of Patient Outcome and Satisfaction after Surgical Treatment of Adolescent Idiopathic Scoliosis Using Scoliosis Research Society-30

BACKGROUND

Adolescent idiopathic scoliosis (AIS) may lead to physical and mental problems. It also can adversely affect patient satisfaction and the quality of life. In this study, we assessed the outcomes and satisfaction rate after surgical treatment of AIS using scoliosis research society-30 questionnaire (SRS-30).

METHODS

We enrolled 135 patients with AIS undergoing corrective surgery. Patients were followed for at least 2 years. We compared pre- and post-operative x-rays in terms of Cobb's angles and coronal balance. At the last visit, patients completed the SRS-30 questionnaire. We then assessed the correlation between radiographic measures, SRS-30 total score, and patient satisfaction.

RESULTS

Cobb's angle and coronal balance improved significantly after surgery (P<0.001). The scores of functional activity, pain, self-image/cosmesis, mental health, and satisfaction were 27±4.3, 26±2.5, 33±5.2, 23±3.5, and 13±1.8, respectively. The total SRS-30 score was 127±13. Radiographic measures showed significant positive correlation with satisfaction and SRS-30 total scores. There was also a positive correlation between satisfaction and self-image/cosmesis domain scores.

CONCLUSIONS

The greater the radiographic angles were corrected the higher the SRS-30 total score and patient satisfaction were. It is intuitive that the appearance and cosmesis is of most important factor associated with patient satisfaction.

Three-dimensional vertebral wedging and pelvic asymmetries in the early stages of adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Scoliosis is a three-dimensional (3D) deformation of the spine and the pelvis. Although the relation between the pelvic asymmetries and scoliosis progression was proposed by several authors, it has not been documented over time in adolescent idiopathic scoliosis (AIS).

PURPOSE

The objective was to determine whether vertebral wedging and pelvic asymmetries progress in the early stages of AIS before any orthopedic treatment.

STUDY DESIGN

The study design included an observational cohort study.

PATIENT SAMPLE

Nineteen AIS girls participated in this study.

OUTCOME MEASURES

The outcome measures were pelvic and spine geometries from simultaneous biplanar radiographs.

METHODS

At the diagnosis, the girls (12.6±1.3 years) had a Cobb angle of 13.9°±6.0°. At the end of their observation period (11 months on average), the scoliosis progressed to 20.5°±5.5°. Bone 3D geometry was reconstructed from biplanar radiographs. Sagittal and frontal wedgings were calculated for five vertebral levels, namely, at the apex and at the two vertebral bodies above and below it. The pelvic geometry was described using five 3D homologous right-left lengths to estimate pelvic asymmetries. Paired t tests were performed on vertebral wedging and pelvic asymmetries to assess their progression between the two evaluations. Principal component (PC) analyses were applied to determine whether vertebral wedging or pelvic asymmetries were predominant at each evaluation.

RESULTS

Vertebral wedging was present at the diagnosis (1.76°-5.92°) and generally did not progress until brace prescription. The mean difference between the right and left pelvic normalized lengths was 1.4% and 2.4% for the initial and final evaluations, respectively. Results revealed the width of the right pelvis to be superior by 3%, and this asymmetry progressed to 4.0%. Principal component analysis revealed that initial vertebral wedging was present in seven out of eight parameters of the first three PCs, whereas at the final examination, vertebral wedging and pelvic asymmetries were evenly present.

CONCLUSIONS

Our study confirms the presence of vertebral wedging at the early stages of scoliosis. This is the first to document the association between spinal and pelvic deformities over time. Pelvic asymmetries could be responsible for trunk muscle imbalances and lead to reduced neuromuscular control reported in AIS patients. These results could influence body brace fitting.

Selection of the Lowest Level for Fusion in Adolescent Idiopathic Scoliosis-A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review of studies reporting pain as a long-term outcome after spinal fusion surgery for treatment of adolescent idiopathic scoliosis.

OBJECTIVE

To identify studies that report pain after spinal fusion surgery for scoliosis based on the distal extent of fusion and to combine results to determine if there is an increased incidence of back pain in patients treated with fusion to the lower lumbar spine.

SUMMARY OF BACKGROUND DATA

The methods and results of existing studies are inconsistent and only occasionally reach statistical significance. No thorough review of the available information has been published.

METHODS

An electronic literature search was performed to identify studies that met predetermined eligibility criteria. Data extracted included number of cases fused to L3 or above, to L4 or L5, and the number of those cases experiencing pain. Further, when possible, the pain variable was stratified into severe or mild categories to allow a more specific subanalysis.

RESULTS

Eight studies met inclusion criteria. The meta-analysis for occurrence of pain, the primary outcome, resulted in a final odds ratio of 1.29 (95% CI 0.91-1.82, n = 1,155). When pain was stratified according to severity and only those cases in the severe category considered for meta-analysis, the resulting odds ratio was 1.43 (95% CI 0.72-2.82, n = 900). Neither analysis reached statistical significance.

CONCLUSIONS

Although there was a trend toward increased pain in patients whose fusion extended to L4 or L5, there was no statistically significant association between the distal level of fusion and incidence of subsequent back pain, both with and without stratification according to severity of back pain. Because of the limitations of published research, the effect of fusion into the lower lumbar spine on back pain is unknown. Higher quality studies with long-term follow-up and consistent reporting of outcomes are needed.

Unintended Change of Physiological Lumbar Lordosis and Pelvic Tilt After Posterior Spinal Instrumentation and Fusion for Adolescent Idiopathic Scoliosis: How Much Is Too Much?

STUDY DESIGN

Retrospective review of prospective multicenter adolescent idiopathic scoliosis (AIS) database.

OBJECTIVES

To investigate the effect of decreased lumbar lordosis (LL) on measured pelvic tilt (PT) after posterior spinal instrumentation and fusion for AIS and to test the hypothesis that lumbar spinal fusion resulting in mismatched LL is associated with increased PT.

SUMMARY OF BACKGROUND DATA

Interaction between the spine and pelvis highly influences global sagittal alignment (GSA). In adults, correlation between health-related quality of life measures and LL proportional to a patient-specific pelvic incidence (PI) has been established, although the implications of poor sagittal alignment are less well-defined in AIS. This observation warrants further examination of regional spine contour and its relation to the pelvis in AIS.

METHODS

The authors queried a prospective multicenter database for AIS patients who underwent posterior spinal instrumentation and fusion with lowest instrumented vertebra between L2 and L5 and identified 155 patients with minimum 2 years' follow-up. Lumbar lordosis (T12-S1), LL within fusion, LL below fusion, GSA, PT, and PI were measured preoperatively and at 2 years. Change in PT was compared between patients with matched or mismatched LL based on a common clinical definition (LL = PI + 10) and a research-driven model (LL = 0.56 PI + 33.43).

RESULTS

Thirty-eight percent of patients had decreased LL from before surgery to 2 years after surgery. These patients had significantly higher rates of increased PT (73%) than patients without decreased LL (40%). Multivariate regression demonstrated that change in LL, LL within fusion, and GSA had a significant predictive effect on PT (p < .001). Using either definition of LL, patients with LL less than 2 standard deviations from predicted values were more likely to have increased PT.

CONCLUSIONS

Iatrogenic loss of LL commonly occurs in spine fusion for AIS and is associated with a reciprocal increase in PT. As such, spinal fusion in AIS can have unintended effects on sagittal alignment with currently uninvestigated potential consequences in the future.

Nerve Growth Factor and Estrogen Receptor mRNA Expression in Paravertebral Muscles of Patients With Adolescent Idiopathic Scoliosis: A Preliminary Study

STUDY DESIGN

Comparison of nerve growth factor (NGF) and estrogen receptor (ER)α messenger ribonucleic acid (mRNA) expression in bilateral paravertebral muscles in adolescent idiopathic scoliosis (AIS). This expression in AIS was compared with that of normal control subjects.

OBJECTIVES

To investigate NGF and ERα mRNA expression in bilateral paravertebral muscles in AIS and control subjects to clarify its association with the development and progression of spinal curvature.

SUMMARY OF BACKGROUND DATA

Paravertebral muscle abnormalities in AIS patients have been investigated through various methods. Despite the roles of NGF and ER in human skeletal muscles, the association with idiopathic scoliosis is still unclear.

METHODS

A total of 14 AIS patients (average age, 15.9 ± 2.2 years; average Cobb angle, 48.2° ± 8.9°) and 8 controls (average age, 27.3 ± 9.3 years) were included. Muscle samples were harvested from bilateral paravertebral muscles at the apical vertebral level. Nerve growth factor and ERα mRNA expression was evaluated by the real-time polymerase chain reaction. The researchers compared expression levels in bilateral paravertebral muscles in each group. The expression ratio, the expression at the convex side relative to the concave side, was compared between groups and the correlation between Cobb angle and expression ratio was analyzed.

RESULTS

Nerve growth factor and ERα mRNA expression on the convex side was higher than on the concave side in the AIS group (p = .024 and .007, respectively) and the expression ratio of NGF and ERα in the AIS group was higher than that of control subjects (p = .004 and .017, respectively). The expression ratio of NGF and the Cobb angle were significantly correlated (r = -0.5728; p = .0323).

CONCLUSIONS

In the AIS group, both NGF and ERα mRNA expression was asymmetric. The AIS group had higher expression ratios than control group and the NGF expression ratio was positively correlated to the Cobb angle.

Three-dimensional computed tomography for assessing lung morphology in adolescent idiopathic scoliosis following posterior spinal fusion surgery

OBJECTIVE

To evaluate the changes in lung morphology in subjects with adolescent idiopathic scoliosis (AIS) following posterior spinal fusion surgery.

METHODS

From April 2009 to August 2013, 30 AIS patients (nine males and 21 females) were enrolled in this study. All scans were obtained with the patient in the supine position and the breath held in deep inspiration and performed both before and after surgery. Syngo software was used to manage the computed tomography scan imaging and to calculate the lung volume, lung height and pulmonary cross-sectional area in the apical vertebral plane.

RESULTS

Left lung, right lung and total lung volumes and convex to concave lung volume ratio did not change significantly after corrective surgery. There was a statistically significant improvement in left lung and right lung heights after posterior spinal fusion surgery. However, the pulmonary cross-sectional area in the apical vertebrae plane was smaller postoperatively than preoperatively.

CONCLUSIONS

This study showed that lung height in AIS patients increased significantly immediately postoperatively whereas lung volume did not change significantly. Thoracic symmetry was improved postoperatively in these patients.

Evaluation of quality of life and risk factors affecting quality of life in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a common disease leading to spinal deformity in children ages 10 and over. With advances in the study of health-related quality of life (HRQoL), greater attention has been given to the quality of life (QoL) of patients with AIS and their perception of deformity instead of just focusing on improving the rate of surgical correction. This article provides an overview of the methods of evaluating HRQoL and it analyzes several main factors affecting QoL, such as severity of disease, method of treatment, gender, and social environment, based on previous studies of patients with AIS. The authors believe that radiological studies should no longer be taken as the only indicator of postoperative therapeutic evaluation and hope to build a new evaluation system with assessment of QoL for patients with AIS.

Effect of a spinal brace on postural control in different sensory conditions in adolescent idiopathic scoliosis: a preliminary analysis

BACKGROUND

Despite the positive effects of spinal braces on postural stability, they may constrain movement, resulting in poor balance control in patients with adolescent idiopathic scoliosis (AIS). Therefore, assessment of postural dynamics may aid in designing new less-constraining braces.

OBJECTIVES

The effects of a spinal brace on postural stability and Cobb angle were investigated in this study.

METHODS

Thirteen pediatric patients (10 females, three males) with AIS were recruited to participate in the study. Cobb angle was assessed by X-ray analyses, and postural stability was tested by computerized dynamic posturography in braced and unbraced conditions. A polyethylene underarm corrective spinal brace was fabricated for the subjects.

RESULTS

Thoracic and lumbar curvature decreased to 18.88 ± 11.73° and 17.70 ± 10.58°, respectively, after bracing (p < 0.05). Lower equilibrium scores were observed in the "eyes closed" condition and higher scores in the "eyes closed with a swaying support" condition; higher composite equilibrium scores were also observed for the sensory organization test (p < 0.05) in the braced condition. Lower scores were observed for the "toes-up adaptation test" in the braced condition (p < 0.05). In the braced condition, the reaction time was slower in the right-backward direction and movement velocity was higher in the right-front direction on the limits of stability test (p < 0.05). Furthermore, lower on-axis velocity during forward/backward dynamic balance control was observed in the braced condition (p < 0.05).

CONCLUSIONS

Wearing a spinal brace improved postural stability in terms of increased proprioception, equilibrium performance, and rhythmic movement ability in patients with AIS.

Evaluation of a Patient-Specific Finite-Element Model to Simulate Conservative Treatment in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective validation study.

OBJECTIVES

To propose a method to evaluate, from a clinical standpoint, the ability of a finite-element model (FEM) of the trunk to simulate orthotic correction of spinal deformity and to apply it to validate a previously described FEM.

SUMMARY OF BACKGROUND DATA

Several FEMs of the scoliotic spine have been described in the literature. These models can prove useful in understanding the mechanisms of scoliosis progression and in optimizing its treatment, but their validation has often been lacking or incomplete.

METHODS

Three-dimensional (3D) geometries of 10 patients before and during conservative treatment were reconstructed from biplanar radiographs. The effect of bracing was simulated by modeling displacements induced by the brace pads. Simulated clinical indices (Cobb angle, T1-T12 and T4-T12 kyphosis, L1-L5 lordosis, apical vertebral rotation, torsion, rib hump) and vertebral orientations and positions were compared to those measured in the patients' 3D geometries.

RESULTS

Errors in clinical indices were of the same order of magnitude as the uncertainties due to 3D reconstruction; for instance, Cobb angle was simulated with a root mean square error of 5.7°, and rib hump error was 5.6°. Vertebral orientation was simulated with a root mean square error of 4.8° and vertebral position with an error of 2.5 mm.

CONCLUSIONS

The methodology proposed here allowed in-depth evaluation of subject-specific simulations, confirming that FEMs of the trunk have the potential to accurately simulate brace action. These promising results provide a basis for ongoing 3D model development, toward the design of more efficient orthoses.

The Use of Intraoperative Traction in Pediatric Scoliosis Surgery: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To study the morbidity and the potential benefits of using intraoperative skeletal traction as an adjunct method for correcting scoliosis.

SUMMARY OF BACKGROUND DATA

Cotrel et al., used intraoperative skeletal traction in all patients in their original series of segmental spinal instrumentation for scoliosis correction (Cotrel et al., Clin Orthop Relat Res 1988;227:10-23). However, the use of intraoperative traction may introduce other forms of surgical morbidity, which has not been systematically studied.

METHODS

Two independent reviewers searched MEDLINE (1948-current) and EMBASE (1980-current) using the keywords scoliosis, intraoperative, and traction in all fields, combined with AND. Studies were subject to full-text assessment against specific inclusion and exclusion criteria; discrepancies between the reviewers were resolved by a third independent reviewer. Data were extracted into standardized extraction tables and papers were critically appraised papers with regards to their relative strengths and weaknesses, with particular attention to the study objective.

RESULTS

Nine papers were included: case report (n = 1), retrospective case series (n = 2), retrospective case-control (n = 6), and studies included both adolescent idiopathic scoliosis (AIS) and neuromuscular scoliosis. Seven studies reported positive effects of intraoperative skeletal traction on diverse outcome measures, such as correction of pelvic obliquity, Cobb angle, and axial plane deformity, as well as precluding the need for an anterior release preceding posterior instrumentation for large curves. Overall, there was only one reported postoperative traction-related complication (anterosuperior iliac spine pressure sore). One paper reported that intraoperative traction may evoke neuromonitoring signal changes in a large proportion of patients undergoing AIS surgery. These changes were responded to intraoperatively by decreasing or removing weight and none of the patients had postoperative neurologic deficits.

CONCLUSION

Isolated intraoperative skeletal traction may be a low-morbidity adjunct to facilitate scoliosis surgery. Further studies are needed to compare outcomes of scoliosis surgery with or without intraoperative skeletal traction.

Association of GPR126 gene polymorphism with adolescent idiopathic scoliosis in Chinese populations

Idiopathic scoliosis is the most common pediatric spinal deformity affecting 1% to 3% of the population, and adolescent idiopathic scoliosis (AIS) accounts for approximately 80% of these cases; however, the etiology and pathogenesis of AIS are still uncertain. The current study aims to identify the relationship between G protein-coupled receptor 126 (GPR126) gene and AIS predisposition, to identify the relationship between the genotypes of the GPR126 SNPs and the clinical phenotypes of AIS. We conducted a case-control study and genotyped twenty SNPs of GPR126 gene including ten exonic SNPs and ten intronic polymorphisms in 352 Chinese sporadic AIS patients and 149 healthy controls. We provided evidence for strong association of three intronic SNPs of the GPR126 gene with AIS susceptibility: rs6570507 A > G (p =0 .0035, OR = 1.729), rs7774095 A > C (p = 0.0078, OR = 1.687), and rs7755109 A > G (p = 0.0078, OR = 1.687). However, we did not identify any significant association between ten exonic SNPs of GPR126 and AIS. Linkage disequilibrium analysis indicated that rs7774095 A > C and rs7755109 A > G could be parsed into one block. The association between the intronic haplotype and AIS was further confirmed in an independent population with 110 AIS individuals and 130 healthy controls (p = 0.046, OR = 1.680). Furthermore, molecular mechanisms underlying intronic SNP regulation of GPR126 gene were studied. Although intronic SNPs associated with AIS didn't influence GPR126 mRNA alternative splicing, there was a strong association of rs7755109 A > G with decreased GPR126 mRNA level and protein levels. Our findings indicate that genetic variants of GPR126 gene are associated with AIS susceptibility in Chinese populations. The genetic association of GPR126 gene and AIS might provide valuable insights into the pathogenesis of adolescent idiopathic scoliosis.

Thoracic and lumbar vertebrae morphology in Lenke type 1 female adolescent idiopathic scoliosis patients

BACKGROUND

Pedicle screws are widely used in adolescent idiopathic scoliosis (AIS) surgeries. Pedicle screw malposition may lead to serious vascular and neurologic complications. Knowledge of the morphometric anatomy of the thoracic and lumbar vertebrae is essential for the surgeon while implanting pedicle screws. It has been reported that there is a reduction of pedicle width at the concavity of the curve in AIS patients. However, it is unclear if gender plays a role in this pedicle width pattern. The goal of this study is to assess the vertebrae morphology in a more homogeneous group of AIS patients - female patients with Lenke type 1 curve.

METHODS

The thoracic and lumbar vertebra and pedicle morphometry of 17 consecutive Lenke type 1 female AIS patients was analyzed based on 1mm fine cut CT scans. Morphometric anatomy of 539 pedicles from T1 to L5 was studied. Measurements included pedicle length, chord length, transverse pedicle width, transverse pedicle angle and vertebral rotation angle.

RESULTS

The mean age of the patients was 14 years old (range 12-18). The mean Cobb angle was 56° (range 43° -88°) and the mean angle of vertebral rotation varied between 4-13.8°. The apical vertebra was between T7 and T11. The transverse pedicle width was significantly smaller (p < 0.05) on the concave side in the apical region of the thoracic spine (T7 and T8), measuring between 2.1-2.2 mm on the concave side and 2.7-3.1 mm on the convex side. Meanwhile, in some upper thoracic vertebrae (T3, T4, T5), the width was significantly bigger (p < 0.05) on the concave side than on the convex side, measuring between 2.8-4 mm on the concave side and 1.8-2.4 mm on the convex side. In the lumbar spine, the width varied between 4.1-9.9 mm without significant differences between the concave and convex sides (p > 0.05). The pedicle length varied between 15.4-28.7 mm and was significantly smaller (p < 0.05) on the concave side at T4, T5 and L2. The chord length was shortest at T1, measuring 32.4 mm and increased gradually to 54.3 mm at L3 but no statistical difference was found between the concave and convex sides. The transverse pedicle angle varied between 11.8° and 35° and was significantly bigger on the concave side at T7 and on the convex side at L1 (p < 0.05).

CONCLUSIONS

The vertebrae morphology in Lenke type 1 female AIS patients is substantially different from the vertebrae in normal spines especially at the apex and in the upper thoracic region. This is consistent with some previous reports which did not distinguish between male and female patients. Our findings suggest that gender does not play a major role in the vertebrae morphology pattern of AIS patients. Furthermore, recognizing this pattern is critical in order to optimize pedicle screw instrumentation and may allow for some leeway adjustments in the pedicle screw trajectory regardless of the methods of implantation.

Association of rs11190870 near LBX1 with adolescent idiopathic scoliosis in East Asians: a systematic review and meta-analysis

BACKGROUND CONTEXT

The rs11190870 single nucleotide polymorphism in the 3'-flanking region of the LBX1 gene has been implicated in the etiology of adolescent idiopathic scoliosis (AIS). A thorough appraisal of the evidence supporting this association has not been previously attempted.

PURPOSE

To provide a comprehensive assessment and synthesis of the currently available evidence on the association between rs11190870 and AIS.

STUDY DESIGN

A systematic review and meta-analysis.

METHODS

This review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. PubMed (MEDLINE), EMBASE, Scopus, and HuGE Literature Finder databases were systematically searched through November 2013 to identify relevant studies following a sensitive strategy. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using the fixed-effect inverse variance model for allelic (T vs. C) and genotypic comparisons.

RESULTS

Meta-analysis of four studies conducted in East Asian populations (n=3,215 AIS cases and n=15,347 controls) found a highly statistically significant and robust association between rs11190870 and AIS. Comparison of summary ORs indicated a codominant model effect of the T allele. Carriers of the TC and TT genotypes were 69% (OR=1.69, 95% CI: 1.48-1.94, p<.001) and 162% (OR=2.62, 95% CI: 2.28-3.02, p<.001), respectively, more likely to have AIS compared with carriers of the CC genotype.

CONCLUSIONS

Based on a comprehensive analysis of the currently available evidence, rs11190870 is likely a susceptibility variant for AIS in East Asians. Further investigation of this association is necessary in other populations.

Adolescent idiopathic scoliosis correction achieved by posteromedial translation using polyester bands: A comparative study of subtransverse process versus sublaminar fixation

PURPOSE

Sublaminar polyester bands have been used in hybrid construct to achieve correction of adolescent idiopathic scoliosis since 2003. Despite the reported safety of the bands, some surgeons remain reluctant at the idea of approaching the canal because of the potential neurological complications reported with the Luque wiring. Sub transverse bands might be an alternative. The present study is the first to compare sublaminar polyester band fixation to fixation of polyester bands around the transverse processes in hybrid constructs used to treat AIS.

METHODS

Two cohorts of consecutive patients treated for thoracic AIS were retrospectively reviewed, with a minimum 2-year follow-up. Posteromedial translation was used for main curve correction in all cases. Sublaminar polyester bands were used in group 1 (20 patients). In group 2 (20 patients), the same implant was used, but the bands were passed around the transverse process instead of the lamina. Radiographic analysis included frontal Cobb angle measurements for each curve, thoracic kyphosis and rotation of the apical vertebra (RVA).

RESULTS

Mean operative time was similar in groups 1 and 2 (235±35 and 240±30minutes, respectively). Mean frontal correction achieved for the main curve was similar in both groups, 62.5±17.4% in group 1 and 54.1±19.4% in group 2. Sagittal correction was similar, with a final mean thoracic kyphosis of 30.9°±9.7° and 27.8°± 6.8° in group 1 and 2, respectively. Correction of RVA was similar in both groups postoperatively, 65.8% (±29.1) and 54.4% (±42.7) in group 1 and 2 respectively. No transverse process or lamina fracture was observed during insertion of the bands or curve correction in any of the groups.

CONCLUSION

This study confirms that anchorage of Universal clamps (UCs) around transverse processes is a safe and efficacious technique in both the frontal and sagittal planes, providing a useful alternative for the correction of moderate AIS. UCs attached to transverse processes can achieve correction of moderate AIS similar to that obtained with sublaminar UCs while further reducing risks of vertebral canal complications.

LEVEL OF EVIDENCE

Level IV.

Relation between self-image score of SRS-22 with deformity measures in female adolescent idiopathic scoliosis patients

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a pathology which affects the individual's functioning in the widely understood physical, psychic, and social aspects. More attention should be paid to patients' perception of self-image when evaluating the spine deformity. The present retrospective study evaluated the associations between the deformity measures and self-image score as determined by the SRS-22 questionnaire in Chinese female AIS patients.

HYPOTHESIS

The self-image score correlates significantly with deformity measures. The location of main curve apex and the number of curve could affect the self-image score.

MATERIALS AND METHODS

We retrospectively reviewed the records of 202 female patients, collected data on patient's age, body mass index, radiographic and physical measures and self-image score of SRS-22 questionnaire. According to the location of main curve apex and the number of curve, the patients were divided to different subgroups. Correlations between deformity measures and self-image score of different groups were evaluated by the Spearman correlation test.

RESULTS

The self-image score correlated negatively with the main Cobb angle, apical vertebral translation (AVT), and razor hump height. There is no significant difference of self-image score between thoracic curve (TC) and thoracolumbar curve (TL/LC) subgroups. And the self-image scores of one-curve, two-curve and three-curve subgroups are similar.

DISCUSSION

For Chinese female AIS patients in our study, self-image was found to correlate negatively with the main Cobb angle, AVT and razor hump height. And the location of scoliosis apex and the number of curve are not influencing factors of self-image perception.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Functional aerobic exercise capacity limitation in adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Exercise limitation has been described in patients with adolescent idiopathic scoliosis (AIS); however, whether the walking performance is impaired in these patients should be elucidated.

PURPOSE

Thus, we aimed to evaluate the physiologic responses to the incremental shuttle walk test (ISWT) in patients with AIS.

STUDY DESIGN/SETTING

Cross-sectional study.

PATIENT SAMPLE

Twenty-nine patients with AIS and 20 healthy adolescents aged between 11 and 18 years old.

OUTCOME MEASURES

Oxygen uptake (VO₂), incremental shuttle walk distance (ISWD), ΔVO₂/Δwalking velocity, ΔHR/ΔVO₂, ΔVE/ΔVCO₂, and linearized Δtidal volume (VT)/ΔlnVE, forced expiratory volume in the first second of expiration (FEV1), and forced vital capacity (FVC).

METHODS

We performed two ISWTs, and the data used were acquired in the second test. We also evaluated the lung function and respiratory muscle strength through spirometry test and manovacuometry, respectively. All authors confirm that there are no conflicts of interest. To compare the means or medians of variables between patients and healthy subjects, we used the unpaired t test or Mann-Whitney U test, respectively. The correlations were assessed by Pearson or Spearman coefficients according to the distribution of the studied variables. The probability of alpha error was set at 5% for all analyses.

RESULTS

Adolescent idiopathic scoliosis patients showed significant lower values of ISWD, VO₂, and ventilation at the end of the ISWT, as well as lower FEV₁ and FVC; they also presented significantly shallower slope of ΔVT/ΔlnVE, whereas VO₂ related significantly with ISWD (r=0.80), FVC (r=0.78), FEV₁ (r=0.73), and ΔVT/ΔlnVE (r=0.58).

CONCLUSIONS

Adolescent idiopathic scoliosis correlated to walking limitation and was associated to reduced pulmonary function and worse breathing pattern during exercise. Our results suggest that walking-based aerobic exercises should be encouraged in these patients.

Mega-granuloma After Using the Universal Clamp for Adolescent Idiopathic Scoliosis: What Is It and Can It Be Prevented?

STUDY DESIGN

Clinical case series.

OBJECTIVE

To characterize the postoperative course and histopathology of peri-implant tissue of adolescent idiopathic scoliosis patients who experienced postoperative development of an aseptic soft tissue reaction, with granulomas adjacent to the sublaminar polyethylene terephthalate strap-titanium clamp used in Zimmer's Universal Clamp (UC) spinal fixation system after spinal surgery.

BACKGROUND SUMMARY

The UC was designed for use with spinal deformity procedures in place of pedicle screws, hooks, or sublaminar wiring in fusion constructs. Recent studies of the UC lack emphasis on implant-related postoperative complications.

METHODS

A total of 26 consecutive patients who underwent spinal deformity correction for scoliosis were reviewed for implant-related postoperative complications. Histology, scanning electron microscopy with energy-dispersive X-ray spectroscopy, fractional culture/biopsy, and Gram stain examination of the peri-implant tissue of patients with complications was performed.

RESULTS

The authors reviewed 26 cases for correction of scoliosis. Two patients with adolescent idiopathic scoliosis who used the UC experienced implant-related complications with development of an aseptic soft tissue reaction with granulomas adjacent to the sublaminar polyethylene terephthalate straps-titanium clamp mechanism of the UC 8 months after AIS correction surgery. There were no signs or symptoms of wound infection. Gram stain revealed no organisms. There were many neutrophils and the surface of the wound revealed rare Staphylococcus aureus but the deep portions of the wounds were negative for organisms. Histopathology revealed extensive granulation tissue and histiocytes with engulfed birefringent particles or debris, and scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis revealed macrophages containing many particles identified as titanium.

CONCLUSIONS

adolescent idiopathic scoliosis patients who use the novel UC construct may develop postoperative foreign-body reaction.

Brace treatment is effective in idiopathic scoliosis over 45°: an observational prospective cohort controlled study

BACKGROUND CONTEXT

Recently, positive results in bracing patients with idiopathic scoliosis (IS) above 45° who refused surgery have been presented in a retrospective study. Obviously, this can give only an efficacy (EA) analysis, as there is neither a control group, nor it is possible to know failures because of dropouts.

PURPOSE

To present the prospective results of bracing patients affected by IS above 45° and still growing.

STUDY DESIGN

Prospective study including all IS patients with 45° or more, Risser stage 0 to 4, who had their first evaluation in our institute, an outpatient clinic specialized in scoliosis evaluation and conservative treatment, from March 1, 2003 to December 21, 2010 and utterly denied any surgical intervention.

PATIENT SAMPLE

Of 59 patients, we excluded 2 patients still in treatment and 57 (11 males) patients were included. At the beginning of the study, they were 15 years 3±22 months of age, had 52.5° Cobb (range, 45°-93°), and Risser 2 (0-4). Thirty-nine accepted a full-time brace treatment (BG) to try avoiding surgery, 18 refused any treatment and served as controls (CG).

OUTCOME MEASURES

Physiological measures: radiographic and clinical data.

METHODS

Treatment: A year of full-time Sforzesco brace (23 hours/day) or Risser cast (8-12 months) and gradual weaning after Risser 3; all patients performed exercises; and International Society on Scoliosis Orthopaedic and Rehabilitation TREATMENT management criteria were respected. Analyses: EA in patients who completed treatment/observation (34 in BG and 10 in CG) and intent-to-treat (ITT) with worst case analysis in the whole population. Relative risk (RR) and 95% confidence interval (CI) have been computed.

RESULTS

Efficacy: failures were 23.5% in BG and 100% in CG. Intent-to-treat: failures were 20.5% in BG and 55.6% in CG. Relative risks of failure in CG were 4.3 (95% CI, 3.6-4.9) in EA and 2.7 (95% CI, 2.0-3.5) in ITT (p<.05). Percentage of patients (53.8%) improved: RRs of improvement in BG were 1.6 (95% CI, 1.46-1.9) in EA and 1.9 (95% CI, 1.6-2.2) in ITT (p<.05). Patients who joined the treatment achieved a 10.4°±10.7° Cobb improvement, an ATR reduction of 4.2°±4.3°, and an esthetic improvement of 2.8±1.9 of 12 points (TRACE). At the end, in BG, 24 patients were below 45° and 6 patients below 35°.

CONCLUSIONS

Through this study we can conclude that the conservative brace plus exercises treatment (if correctly performed and managed) is a suitable alternative for those patients who reject any surgical intervention for IS above 45°. But we could also conclude that a good brace treatment should be considered as the first choice to try avoiding fusion because of the high sanitary and social costs of surgery.

Is Breast Asymmetry Present in Girls with Adolescent Idiopathic Scoliosis?

STUDY DESIGN

Cross-sectional descriptive study.

OBJECTIVES

To characterize breast asymmetry (BA), as defined by breast volume difference, in girls with significant adolescent idiopathic scoliosis (AIS), using magnetic resonance imaging (MRI).

SUMMARY AND BACKGROUND

BA is a frequent concern among girls with AIS. It is commonly believed that this results from chest wall deformity. Although many women exhibit physiological BA, the prevalence is not known in adolescents and it remains unclear if it is more frequent in AIS. Breasts vary in shape and size and many ways of measuring them have been explored. MRI shows the highest precision at defining breast tissue.

METHODS

Thirty patients were enrolled on the basis of their thoracic curvature, skeletal and breast maturity, without regard to their perception on their BA. MRI acquisitions were performed in prone with a 1.5-Tesla system using a 16-channel breast coil. Segmentation was achieved using the ITK-SNAP 2.4.0 software and subsequently manually refined.

RESULTS

The mean left breast volume (528.32 ± 205.96 cc) was greater compared with the mean right breast volume (495.18 ± 170.16 cc) with a significant difference between them. The mean BA was found to be 8.32% ± 6.43% (p < .0001). A weak positive correlation was observed between BA and thoracic Cobb angle (0.177, p = .349) as well as thoracic gibbosity angle (0.289, p = .122). The left breast was consistently larger in 65.5% of the patients. Twenty patients (66.7%) displayed BA ≥5%.

CONCLUSIONS

We have described BA in patients with significant AIS using MRI. This method is feasible, objective, and very precise. The majority of patients had a larger left breast, which could compound the apparent BA secondary to trunk rotation. In many cases, BA is present independently of thoracic deformity. This knowledge will assist in counseling AIS patients in regards to their concerns with BA.

Risk Factors for Coronal Decompensation After Posterior Spinal Instrumentation and Fusion in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective review of multicenter data set with adolescent idiopathic scoliosis (AIS) patients with at least 2 years of follow-up after posterior spinal instrumentation and fusion (PSIF).

OBJECTIVES

The purpose of this study is to investigate risk factors for coronal decompensation 2 years after PSIF for AIS.

SUMMARY OF BACKGROUND DATA

Coronal decompensation is a potential complication of spinal instrumentation for AIS. This can result in problems requiring revision surgery.

METHODS

Demographic, clinical, and radiographic measures were reviewed on 890 identified patients. Coronal decompensation was defined as a change farther away from midline from 6 weeks postoperatively to 2 years in any one of the following radiographic parameters: change in coronal balance >2 cm; change in coronal position of the lowest instrumented vertebra (LIV) >2 cm; change in thoracic trunk shift >2 cm; or change in LIV tilt angle >10°. Patients with decompensation were compared to those without. The relationship between the LIV and lowest end vertebra (LEV) was examined as an independent variable.

RESULTS

Two years postoperation, 6.4% (57/890) of patients exhibited coronal decompensation. Multivariate regression revealed that decompensated patients were twice as likely to be male, have lower preoperative Risser score, and lower percentage major curve correction. The relationship between the LIV and LEV as well as quality of life surveys were not significantly different between decompensated and nondecompensated patients at 2 years.

CONCLUSIONS

Two years after PSIF, 6.4% of patients with AIS exhibit radiographic coronal decompensation. Although this study did not demonstrate a significant association between the relationship of LIV and LEV and decompensation 2 years postoperation, results of this study indicate that skeletal immaturity, male gender, and less correction of the major curve may be related to higher rates of coronal decompensation.

Gait stability improvement after fusion surgery for adolescent idiopathic scoliosis is influenced by corrective measures in coronal and sagittal planes

To achieve optimal results after fusion for adolescent idiopathic scoliosis (AIS), radiographic parameters must be aligned with motion and performance. The effects of fusion on balance are poorly understood. Center of mass (COM) excursion and instantaneous interaction with center of pressure (COP) provides information about patients' balancing ability during gait. This study investigates the interaction between COM and COP (COM-COP) in AIS patients before and one year after spine fusion and determines what radiographic goals predict restoration of harmonious COM-COP. This was a prospective study that investigated sixteen adolescents with AIS curvature >30˚ requiring surgical correction. Clinical outcomes measures, X-rays, and 3D motion-capture gait analysis were collected. Sagittal and coronal COM and COP offsets and inclination angles were calculated from positional data. COM excursion was calculated as peak COM displacement based on mediolateral and vertical deviation from a line fitted to the patient's path. Radiographic parameters were measured to determine variables predictive of change in COM excursion. Post-operatively, average COM peak displacement decreased (42.6 to 13.1 mm, p=0.001) and COM peak vertical displacement remained unchanged (17.0 to 16.3 mm, p=0.472). COM-COP inclination angles reduced in the coronal, but not sagittal plane. Coronal lower extremity peak inclination angles reduced (8.8˚ to 7.5˚, p=0.025), correlating with C7 plumb-line offset (R=0.581, p=0.018). Thoracic Cobb, thoracic kyphosis, and C7 plumb-line were predictors of change in COM excursion. Mediolateral COM excursion post-surgery may reflect an attempt to reduce kinetic demands with improved spinal alignment. Although AIS correction has historically focused on the coronal plane, sagittal parameters may be more important for motion than previously theorized.

Progressive Changes in Sagittal Contour After Anterior Spinal Fusion With Instrumentation of Different Sizes for Thoracic Adolescent Idiopathic Scoliosis: Is Continued Posterior Spinal Growth an Issue in Skeletally Immature Children?

STUDY DESIGN

Retrospective analysis of radiographs for a prospective group of 196 adolescent patients with thoracic idiopathic scoliosis after anterior spinal fusion with instrumentation.

OBJECTIVES

To analyze progressive changes in the sagittal profile of immature and mature patients during the first 2 postoperative years.

SUMMARY OF BACKGROUND DATA

In a previous study of similar patients, a flexible 3.2-mm rod construct was used. An additional 15° (average) of kyphosis was seen in 60% of Risser 0 patients. The current patient group had fusion with solid rod (>4.0-mm) instrumentation.

METHODS

All included patients had single anterior rod instrumentation, clinical and radiographic evidence of solid fusion, a minimum follow-up of 2 years, and a coronal progression of ≤5° including adequate biplanar standard radiographs at preoperative, immediate postoperative, and 2-year follow-up visits. Patients were stratified by skeletal maturity and preoperative thoracic kyphosis. Significant sagittal progression was defined as >10°.

RESULTS

Significant sagittal progression that caused the patient to be hyperkyphotic (T5-T12 > 40°) occurred in 18.37% of the 196 study patients. A total of 55 who were group I Risser 0 at the time of surgery and 141 were group II Risser 1-5. Progression occurred much more frequently in Risser 0 patients who had a preoperative T5-T12 of ≥30° (67.67%) versus Risser 1-5 patients (25.00%).

CONCLUSIONS

Compared with the authors' previous work, solid rod instrumentation (>4.0 mm) for anterior spinal fusion for thoracic scoliosis is better at preventing progressive thoracic kyphosis than the flexible rod (3.2 mm). However, when performing a thoracic anterior spinal instrumented fusion in skeletally immature patients when the preoperative T5-T12 sagittal curve is >30° it is recommended to leave a low normal kyphosis (20°) in the instrumented region of T5-T12.

Management decisions for adolescent idiopathic scoliosis significantly affect patient radiation exposure

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) patients treated before the 1990s have a 1% to 2% increased lifetime risk of developing breast and thyroid cancer as a result of ionizing radiation from plain radiographs. Although present plain radiographic techniques have been able to reduce some of the radiation exposure, modern treatment algorithms for scoliosis often include computed tomography (CT) and intraoperative fluoroscopy. The exact magnitude of exposure to ionizing radiation in adolescents during modern scoliosis treatment is therefore unclear.

PURPOSE

To determine the difference in radiation exposures in patients undergoing various forms of treatment for AIS.

STUDY DESIGN

Retrospective cohort.

PATIENT SAMPLE

Patients aged 9 to 18 years with a diagnosis of AIS, followed and/or treated with nonoperative or operative management for a minimum of 2 years.

OUTCOME MEASURES

Number of radiographs and total radiation exposure calculated.

METHODS

The charts and radiographs of patients managed for AIS at a single institution between September 2007 and January 2012 were reviewed. Patients were divided into three groups: operative group, braced group, and observation group. Patient demographics, Cobb angles, and curve types were recorded. The number of radiographs per year that each patient received and the total radiation dose were recorded. The plain radiographic radiation exposure was then combined with the direct exposure recording from ancillary tests, such as fluoroscopy and CT, and a radiation exposure rate was calculated (mrad/y). A single-factor analysis of variance (α=0.01) with a Tukey honest significant difference post hoc analysis was used to test significance between groups.

RESULTS

Two hundred sixty-seven patients were evaluated: 86 operative, 80 brace, and 101 observation. All groups had similar demographics and curve type distribution. The mean initial Cobb angle at presentation was significantly different between the groups: operative (57°±11°), brace (24°±7.9°), and observation (18°±9.4°) (p<.01). There was a significant difference among the groups in terms of the mean number of radiographs received per year; operative group, 12.2 (95% confidence interval [CI]: 10.8-13.5; p<.001); braced group, 5.7 (95% CI: 5.2-6.2; p<.001), and observed group, 3.5 (95% CI: 3.160-3.864; p<.001). The operative group received 1,400 mrad per year (95% CI: 1,350-1,844; p<.001), braced group received 700 mrad per year (95% CI: 598-716; p<.001), and observed group received 400 mrad per year (95% CI: 363-444; p<.001). Importantly, 78% of radiation in the operative group was attributable to the operative fluoroscopy exposure.

CONCLUSIONS

Significant differences exist in the total radiation exposure in scoliosis patients with different treatment regimens, with operative patients receiving approximately 8 to 14 times more radiation than braced patients or those undergoing observation alone, respectively. Operative patients also receive more than twice the radiation per year than braced or observed patients. Almost 78% of the annual radiation exposure for operative patients occurs intraoperatively. Because children are notably more sensitive to the carcinogenic effects of ionizing radiation, judicious use of present imaging methods and a search for newer imaging methods with limited ionizing radiation should be undertaken.

Influence of implant rod curvature on sagittal correction of scoliosis deformity

BACKGROUND CONTEXT

Deformation of in vivo-implanted rods could alter the scoliosis sagittal correction. To our knowledge, no previous authors have investigated the influence of implanted-rod deformation on the sagittal deformity correction during scoliosis surgery.

PURPOSE

To analyze the changes of the implant rod's angle of curvature during surgery and establish its influence on sagittal correction of scoliosis deformity.

STUDY DESIGN

A retrospective analysis of the preoperative and postoperative implant rod geometry and angle of curvature was conducted.

PATIENT SAMPLE

Twenty adolescent idiopathic scoliosis patients underwent surgery. Average age at the time of operation was 14 years.

OUTCOME MEASURES

The preoperative and postoperative implant rod angle of curvature expressed in degrees was obtained for each patient.

METHODS

Two implant rods were attached to the concave and convex side of the spinal deformity. The preoperative implant rod geometry was measured before surgical implantation. The postoperative implant rod geometry after surgery was measured by computed tomography. The implant rod angle of curvature at the sagittal plane was obtained from the implant rod geometry. The angle of curvature between the implant rod extreme ends was measured before implantation and after surgery. The sagittal curvature between the corresponding spinal levels of healthy adolescents obtained by previous studies was compared with the implant rod angle of curvature to evaluate the sagittal curve correction. The difference between the postoperative implant rod angle of curvature and normal spine sagittal curvature of the corresponding instrumented level was used to evaluate over or under correction of the sagittal deformity.

RESULTS

The implant rods at the concave side of deformity of all patients were significantly deformed after surgery. The average degree of rod deformation Δθ at the concave and convex sides was 15.8° and 1.6°, respectively. The average preoperative and postoperative implant rod angle of curvature at the concave side was 33.6° and 17.8°, respectively. The average preoperative and postoperative implant rod angle of curvature at the convex side was 25.5° and 23.9°, respectively. A significant relationship was found between the degree of rod deformation and preoperative implant rod angle of curvature (r=0.60, p<.005). The implant rods at the convex side of all patients did not have significant deformation. The results indicate that the postoperative sagittal outcome could be predicted from the initial rod shape.

CONCLUSIONS

Changes in implant rod angle of curvature may lead to over- or undercorrection of the sagittal curve. Rod deformation at the concave side suggests that corrective forces acting on that side are greater than the convex side.

Reliability and validity of the adapted Dutch version of the revised Scoliosis Research Society 22-item questionnaire

BACKGROUND CONTEXT

As in other fields of medicine, there is an increasing interest among orthopedic surgeons to measure health-related quality of life in adolescent idiopathic scoliosis patients and to evaluate the burden of disease and the effectiveness of different treatment strategies. The development of the revised Scoliosis Research Society 22-item patient questionnaire (SRS-22r) enabled a comprehensive evaluation of health-related quality of life of these patients. Over the years, the SRS-22r gained wide acceptance and has been used in several different countries, languages, and cultures. The SRS-22r has not been translated into Dutch to date.

PURPOSE

To translate the SRS-22r into Dutch and adapt it cross-culturally as outlined by international guidelines and to test its psychometric properties to measure health-related quality of life of adolescent idiopathic scoliosis patients in the Netherlands.

STUDY DESIGN/SETTING

A cross-sectional, multicenter validation study.

PATIENT SAMPLE

A total of 135 adolescent idiopathic scoliosis patients (mean age 15.1 years old) of three major scoliosis centers in the Netherlands were enrolled in this study. Ninety-two (68%) subjects completed the Dutch SRS-22r, Child Health Questionnaire (CHQ)-CF87 (golden standard for adolescents), and Short Form (SF)-36 (golden standard for adults). Two weeks later, 73 (79%) of 92 respondents returned a second SRS-22r. Demographics, curve type, Risser stage, and treatment status were documented.

OUTCOME MEASURES

Floor and ceiling effects, internal consistency, reproducibility, concurrent validity, and discriminative ability of the Dutch version of the SRS-22r questionnaire.

METHODS

For content analysis, SRS-22r domain scores (function, pain, self-image, mental health, and satisfaction with management) were explored and floor and ceiling effects were determined. Cronbach's α was calculated for internal consistency of each domain of the questionnaires and reproducibility was assessed by test-retest reliability analysis. Using Pearson's correlation coefficient, comparison of the domains of the Dutch SRS-22r with the domains of the SF-36 and Child Health Questionnaire-CF87 assessed the concurrent validity. Differences in SRS-22r domain scores between untreated patients with different curve severity determined the discriminative ability of the questionnaire.

RESULTS

The SRS-22r domains as well as the SF-36 and CHQ-CF87 domains demonstrated no floor effects, but the function, pain, and satisfaction with management domains had ceiling effects, indicating the proportion of subjects with the maximum score between 19.6% and 33.0%. Internal consistency was very satisfactory for all SRS-22r domains: Cronbach's α was between 0.718 and 0.852. By omitting question 15, the internal consistency of the function domain increased from 0.746 to 0.827. Test-retest reliability was ≥0.799 for all SRS-22r domains. The function, pain, mental health, and self-image domains correlated under the 0.001 significance level with the corresponding CHQ-CF87 and SF-36 domains. The satisfaction with management domain did not correlate with the other questionnaires. The SRS-22r had the ability to detect differences between groups with different curve severity; patients with a severe scoliotic curvature had significantly lower pain and self-image domain scores than patients with relatively mild scoliosis.

CONCLUSIONS

The Dutch SRS-22r had the properties needed for the measurement of patient perceived health-related quality of life of adolescent idiopathic scoliosis patients in the Netherlands. The Dutch SRS-22r could be used for the longitudinal follow-up of adolescent idiopathic scoliosis patients from adolescence to adulthood and for establishing the effects of conservative or invasive surgical treatment.

Segmental torso masses in adolescent idiopathic scoliosis

BACKGROUND

Adolescent idiopathic scoliosis is the most common type of spinal deformity whose aetiology remains unclear. Studies suggest that gravitational forces in the standing position play an important role in scoliosis progression, therefore anthropometric data is required to develop biomechanical models of the deformity. Few studies have analysed the trunk by vertebral level and none have performed investigations of the scoliotic trunk. The aim of this study was to determine the centroid, thickness, volume and estimated mass, for sections of the scoliotic trunk.

METHODS

Existing low-dose CT scans were used to estimate vertebral level-by-level torso masses for 20 female adolescent idiopathic scoliosis patients. ImageJ processing software was used to analyse the CT images and enable estimation of the segmental torso mass corresponding to each vertebral level.

FINDINGS

The patients' mean age was 15.0 (SD 2.7) years with mean major Cobb angle of 52 (SD 5.9)° and mean patient weight of 58.2 (SD 11.6) kg. The magnitude of torso segment mass corresponding to each vertebral level increased by 150% from 0.6kg at T1 to 1.5kg at L5. Similarly, segmental thickness from T1-L5 increased inferiorly from a mean 18.5 (SD 2.2) mm at T1 to 32.8 (SD 3.4) mm at L5. The mean total trunk mass, as a percentage of total body mass, was 27.8 (SD 0.5) % which was close to values reported in previous literature.

INTERPRETATION

This study provides new anthropometric reference data on segmental (vertebral level-by-level) torso mass in adolescent idiopathic scoliosis patients, useful for biomechanical models of scoliosis progression and treatment.

Does the size of the rod affect the surgical results in adolescent idiopathic scoliosis? 5.5-mm versus 6.35-mm rod

BACKGROUND CONTEXT

Favorable clinical outcomes of surgical treatment with Cotrel-Dubousset instrumentation (CDI) or instrumentations that follow the principles of CDI, for adolescent idiopathic scoliosis (AIS) have been reported. However, there are few studies concerning the results with rods of different sizes.

PURPOSE

To find out whether the rod size affects the surgical results for AIS.

STUDY DESIGN

A retrospective cohort study based on the same spinal system with different sizes of rod.

PATIENT SAMPLE

A consecutive series of 93 patients, who underwent posterior correction with posterior instrumentation and fusion for AIS, were included and retrospectively analyzed.

OUTCOME MEASURES

Postoperative radiologic outcomes were evaluated using coronal curves, percentage of curve correction, and coronal global balance.

METHODS

Ninety-three patients treated during the period January 2000 to December 2008 were included in this study; 48 patients were treated with the Cotrel-Dubousset Horizon (CDH) M10 system with a 6.35-mm rod from January 2000 through December 2004, and a CDH M8 was used with a 5.5-mm rod in another 45 patients from January 2005 through December 2008. The Cobb angle, Risser grade, coronal curves, flexibility of curve, percentage of curve correction, coronal global balance, operative time, and estimated blood loss were measured and analyzed. The same parameters were used when the patient was followed at the OPD. All of the patients underwent regular follow-up for at least 2 years.

RESULTS

No statistical significance was observed in the demographic data, including age, sex, BMI, and Risser grade, between these 2 groups. The overall average percentage of correction was 60.0%±12.7%: 60.7%±12.5% for the CDH M10 group, and 59%±13.1% for the CDH M8 group. At the final follow-up, the overall average loss of correction was 4.8±3.9° for the CDH M10 group, and 4.3±4.0° for the CDH M8 group. The average percentage of correction at the final follow-up was 50.9%±15.1% for the CDH M10 group, and 51.1%±16.1% for the M8 group. No statistical significance could be observed in the radiologic parameters between these 2 groups.

CONCLUSION

The radiologic results for the 5.5-mm rod and the 6.35-mm rod were comparable in terms of correction, loss of correction, and coronal global balance.

The 100 Classic Papers in Spinal Deformity Surgery

STUDY DESIGN

Bibliometric review of the literature.

OBJECTIVE

To identify and analyze the top 100 cited articles in spinal deformity surgery.

SUMMARY OF BACKGROUND DATA

The field of spinal deformity surgery is an ever-growing and complex field that owes its development to the work and visions of many dedicated individuals.

METHODS

The authors searched the Thomson Reuters Web of Knowledge for citations of all articles relevant to scoliosis and spinal deformity surgery. The number of citations, authorship, year, journal, and country and institution of publication were recorded for each article.

RESULTS

The most cited article was the 2001 work by Lenke et al. describing a new 2-dimensional classification system of adolescent idiopathic scoliosis used to determine the appropriate vertebral levels to be included in an arthrodesis. The second most cited was Harrington's 1962 article describing the first instrumented method for the treatment of scoliosis. The third most cited article was the 1983 study by King et al. recommending specific vertebral levels for inclusion into spinal arthrodesis. Most articles originated in the United States (62), and most were published in Spine (32). Most were published in the 1990s (28), and the 3 most common topics, in descending order, were adolescent idiopathic scoliosis (28), spinal instrumentation (18), and surgical complications (5). Author Suk had 5 articles in the top 100 list, whereas authors Kim, Liljenqvist, Lonstein, and Weinstein had 3 each. Washington University in St. Louis had 7 articles in the top 100 list.

CONCLUSIONS

This report's identification of the 100 classic articles in spinal deformity surgery allows insight into the development and trends of this challenging subspecialty of spine surgery. Furthermore, this article identifies individuals who have contributed the most to the advancement of spinal deformity surgery and the body of knowledge used to guide evidence-based clinical decision making in spinal deformity surgery today.

Effect of Lowest Instrumented Vertebra on Trunk Mobility in Patients With Adolescent Idiopathic Scoliosis Undergoing a Posterior Spinal Fusion

STUDY DESIGN

Prospective.

OBJECTIVES

The goal of this study was to evaluate the effect of posterior spinal fusion surgery terminating at different lowest instrumented vertebrae (LIV) on trunk mobility in individuals with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Posterior spinal fusion with instrumentation is the standard surgical technique employed in AIS for correcting spine deformities with Cobb angles exceeding 50°. Surgical correction of curve deformity reduces trunk mobility and range of motion. However, conflicting findings from previous studies investigating the impact of different LIV levels on the reduction in trunk mobility after surgery have been reported.

METHODS

The study was designed as a prospective study with 47 patients (7 males and 40 females) with AIS who underwent posterior spinal fusion. Patients were classified into 5 groups based on their surgical LIV level (ie, T12, L1, L2, L3, and L4). Trunk flexion-extension (sagittal plane), lateral bending (coronal plane), and axial rotation (transverse plane) kinematics were assessed during preoperative, 1 year postoperative, and 2 years postoperative evaluation visits.

RESULTS

There were postoperative reductions of 41%, 51%, and 59% in trunk range of motion in the sagittal, coronal, and transverse planes, respectively (p < .0001). A trend toward greater postoperative reductions in peak forward flexion at more distal LIVs was observed (p = .04).

CONCLUSIONS

Fusion reduces trunk mobility in the sagittal, coronal, and transverse planes. More distal LIV fusions limit peak forward flexion to a greater extent which is considered clinically significant. After fusion, the reductions seen in axial rotation, lateral bending, and backward extension do not differ significantly at more distal LIVs.

Comparison of somatosensory evoked potentials between adolescent idiopathic scoliosis and congenital scoliosis without neural axis abnormalities

BACKGROUND CONTEXT

Abnormal somatosensory evoked potentials (SEPs) have been documented in patients with adolescent idiopathic scoliosis (AIS) with different cure severity. However, few studies investigated whether abnormal SEPs were the cause or effect of idiopathic scoliosis.

PURPOSE

The purpose of this study was to investigate the significance of abnormal SEPs in patients with AIS, and to explore its effect on the etiopathogenesis of AIS.

STUDY DESIGN/SETTING

This study evaluated SEPs in patients with AIS and congenital scoliosis (CS) with similar curve pattern and severity both in coronal and sagittal planes.

PATIENT SAMPLE

Female patients with AIS and CS in our spine surgery center from 2000 to 2009 were recruited for this study.

OUTCOME MEASURES

Rate of abnormal SEPs.

METHODS

Posterior tibial nerve SEPs (PTN-SEPs) were performed on female patients with AIS and CS. The inclusion criteria were patients with AIS with a Lenke type 1 curve and patients with CS with right thoracic curve (apex between T5 and T12) and normal sagittal profile (kyphosis less than 50° measured from T2 to T12). All patients were evaluated with total spine magnetic resonance imaging, and those with neural axis abnormalities were excluded. The patients with neurological deficits on detailed physical examination were also excluded. Absence of SEPs waveforms or prolongation of peak latency or asymmetrical peak latency were defined as pathological change. The incidence of pathological SEPs and clinical characteristics were compared between patients with AIS and patients with CS.

RESULTS

Forty-six patients with AIS and 33 patients with CS were included in this study. There was no significant difference in coronal and sagittal Cobb angle between the two groups. The rate of abnormal SEPs was 32.6% (15/46) and 12.1% (4/33) in AIS and CS groups, respectively, and the difference was statistically significant (p<.05).

CONCLUSION

Somatosensory pathway dysfunction could be found in both AIS and CS without neural axis abnormalities, and the patients with AIS tended to have higher rates of somatosensory disorders than patients with CS with similar scoliosis curve, which indicates that both scoliosis curve and primary etiopathogenic factor contribute to the sensory deficit in patients with AIS.

The Utility of 3-Dimensional-Navigation in the Surgical Treatment of Children With Idiopathic Scoliosis

STUDY DESIGN

Ambispective study of patients undergoing surgical correction of adolescent idiopathic scoliosis.

OBJECTIVE

To evaluate the accuracy of screw placement using preoperative 3-dimensional (3D) computed tomography (CT)-based navigation with intraoperative fluoroscopic guidance compared with freehand placement.

SUMMARY OF BACKGROUND DATA

Pedicle screws placed in deformed vertebrae have a high malposition rate. The use of navigation-based systems has increased placement accuracy.

METHODS

Intraoperative registration of patient anatomy to preoperative 3D-CT was performed using anatomic landmarks. When registration accuracy was high (mean square error, <1.0 mm), screw tracts were drilled under navigation guidance; when the error was >1.0 mm, re-registration was performed. The researchers documented times for registration, navigation, and screw placement, and the number of passes. Results were compared with outcomes in cases operated on with freehand screw placement.

RESULTS

A total of 62 patients were included (54 females and 8 males; mean age was 15.1 years [range, 12-18 years]). Mean deformity was 67° (range, 52° to 80°). Mean follow-up was 35 months (range, 42-19 months). In the navigation group, 710 pedicle screws were placed. Mean times were 55 seconds for tracker placement, 94.5 seconds per vertebra for patient registration, 131.1 seconds for screw tract formation on the concave side of the deformity, and 129.5 seconds on the convex side. Average total procedure time was 3.5 hours (range, 2-7 hours). Mean overall registration accuracy was 0.7 mm. Pedicle integrity was breached in 1.6% trajectories. In the freehand group, 470 pedicle screws were placed. Average time for screw placement was 135.2 seconds (p < .001 vs. navigation). Pedicle integrity was breached in 5.1% of trajectories (p < .0001 vs. navigation). No patient developed neurological or other complications. There was no destabilization of the instrumented spine during short- or long-term follow-up.

CONCLUSIONS

Intraoperative optic fluoroscopic navigation based on anatomic landmark registration to preoperative 3D-CT spine images enables precise pedicle screw placement with only a minor increase in pedicle preparation time in patients with adolescent idiopathic scoliosis.

Comparison of Typical Thoracic Curves and Atypical Thoracic Curves Within the Lenke 1 Classification

STUDY DESIGN

Retrospective study.

OBJECTIVES

To examine the characteristics of Lenke type 1 curves based on the level of the apical vertebra.

SUMMARY OF BACKGROUND DATA

The Lenke classification is the most used system for adolescent idiopathic scoliosis, with approximately 50% of the curves falling into the Lenke 1 curve type category.

METHODS

A total of 611 Lenke 1 curves in a prospectively collected multicenter adolescent idiopathic scoliosis study were analyzed. Minimum follow-up was ≥ 2 years. Curves were subdivided into 3 groups according to their apex: the typical Lenke 1 curve group included apices from T7/8 to T10 (511 patients), the proximal group included apices from T4 to T7 (45 patients), and the distal group included apices from T10/11 to T11/12 (50 patients). Preoperative and postoperative radiographic and clinical outcomes were compared among the 3 groups.

RESULTS

The proximal and distal groups included significantly more left thoracic curves (proximal: 29%; typical: 1.8%; distal: 19%; p < .01). Flexibility of the main thoracic curve was significantly different among the 3 groups (proximal: 32% ± 17%; typical: 46% ± 18%; distal: 57% ± 18%; p < .001). The distal group included significantly more "A" lumbar modifiers (proximal: 29%; typical: 53%; distal: 96%; p < .01) and had curves characteristics similar to King type 4 curves (L4 tilted to the right: Lenke 1AR). The average lowest instrumented vertebra was significantly lower in the distal group (proximal: T12; typical: L1; distal: L2; p < .01). The proximal group had significantly greater thoracic kyphosis (proximal: 30° ± 18°; typical: 20° ± 13°, distal: 20° ± 10°; p < .001) and more fusion segments (proximal: 10; typical: 9; distal: 9; p < .03).

CONCLUSIONS

Curves categorized as Lenke 1 curves were less homogeneous than expected. Using only the Lenke type 1 designation to define a study population may introduce unintended bias to the study design.

Blood Loss Reduction During Surgical Correction of Adolescent Idiopathic Scoliosis Utilizing an Ultrasonic Bone Scalpel

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVES

To evaluate blood loss associated with posterior spinal fusion in adolescent idiopathic scoliosis patients performed with and without the use of an ultrasonic bone scalpel (UBS).

SUMMARY OF BACKGROUND INFORMATION

After using an ultrasonic-powered bone-cutting device with recent Food and Drug Administration approval for use in the spine, the authors perceived a reduction in bone bleeding associated with the cut boney surfaces.

METHODS

The first 20 patients with adolescent idiopathic scoliosis who underwent posterior spinal fusion using the UBS by a single surgeon were compared with 2 control groups: 1) the 20 most recent prior cases of the same surgeon before beginning use of the bone scalpel; and 2) 20 cases of the same surgeon before using the bone scalpel matched based on Cobb angle magnitudes. Both cases and controls had Ponte-type posterior apical releases; none had an anterior procedure. Patient demographic and surgical data were analyzed using analysis of variance (p < .05).

RESULTS

Preoperatively, the UBS group was similar to both control groups in terms of primary and secondary curve magnitudes, number of levels fused, number of levels with Ponte release, antifibrinolytic use, and patient age (p > .05). The UBS group had significantly less estimated blood loss (EBL) (550 ± 359 mL), Cell Saver blood transfused (94 ± 146 mL), and EBL per level fused (48 ± 30 mL) than the most recent controls (EBL: 799 ± 376 mL; Cell Saver: 184 ± 122 mL; EBL/level fused: 72 ± 28 mL) and Cobb-matched controls (EBL: 886 ± 383 mL; Cell Saver: 198 ± 115 mL; EBL/level fused: 78 ± 30 mL) (p < .05). Surgical times were equivalent and there were no dural tears in any group.

CONCLUSIONS

The use of an ultrasonic bone scalpel to perform the bone cuts associated with facetectomies and apical Ponte-type posterior releases resulted in significantly less bleeding compared with cuts made with standard osteotomes and rongeurs, limiting overall blood loss by 30% to 40%.