Segmental vs non-segmental thoracic pedicle screws constructs in adolescent idiopathic scoliosis: is there any implant alloy effect?

PURPOSE

The aim of this study is to understand how many anchor sites are necessary to obtain maximum posterior correction of idiopathic scoliotic curve and if the alloy of instrumentation, stainless steel or titanium, may have a role in the percent of scoliosis correction.

METHODS

We reviewed 143 consecutive patients, affected by AIS (Lenke 1-2), who underwent a posterior spinal fusion with pedicle screw-only instrumentation between 2002 and 2005. According to the implant density and alloy used we divided the cohort in four groups.

RESULTS

All 143 patients were reviewed at an average follow-up of 7, 2 years, the overall final main thoracic curve correction averaged 61.4%, whereas the implant density within the major curve averaged 71%. A significant correlation was observed between final% MT correction and preoperative MT flexibility and implant density.

CONCLUSIONS

When stainless steel instrumentation is used non-segmental pedicle screw constructs seem to be equally effective as segmental instrumentations in obtaining satisfactory results in patients with main thoracic AIS. When the implant alloy used is titanium one, an implant density of ≥60% should be guaranteed to achieve similar results.

Role of Clavicle Chest Cage Angle Difference in Predicting Postoperative Shoulder Balance in Lenke 5C Adolescent Idiopathic Scoliosis Patients after Selective Posterior Fusion

OBJECTIVE

To evaluate the role of preoperative clavicle chest cage angle difference (CCAD) on postoperative radiographic shoulder imbalance, patient's satisfaction and surgeon's fulfillment in Lenke 5 adolescent idiopathic scoliosis (AIS). CCAD, as a novel radiographic parameter, has proven to be a reliable predictor for postoperative shoulder imbalance in Lenke 1 AIS patients. However, the value of CCAD in predicting shoulder balance has never been evaluated in Lenke 5 AIS patients.

METHODS

A total of 42 Lenke 5C AIS patients aged from 10 to 18 years old with a minimum 2-year follow-up were enrolled for evaluation. All patients underwent selective posterior spinal instrumentation and fusion using the all segmental pedicle screw technique by the same surgical team. The fusion levels were determined according to the Lenke criteria. Shoulder height difference (SHD) and CCAD were measured on anteroposterior (AP) standing radiographs. The patients' satisfaction and the surgeons' fulfillment were evaluated using a questionnaire. A receiver operative characteristic curve analysis was performed to explore the threshold values of preoperative CCAD in the prediction of the final follow-up radiographic shoulder imbalance, patients' satisfaction and surgeons' fulfillment.

RESULTS

The average preoperative Cobb angle of the main curve was 46.8° ± 4.8°, and the average immediate postoperative Cobb angle was 13.3° ± 2.6°, representing an average surgical correction rate of 75.6% ± 8.5%. The average follow-up time was 29.2 months. At the last follow-up, the value of preoperative CCAD was significantly higher in patients with unbalanced shoulders (SHD ≥ 10 mm). At the final follow-up, 66.7% (28/42) of the patients were satisfied with their appearance, while 33.3% (14/42) of the patients were not satisfied with their appearance. At the final follow-up, 61.9% (26/42) of the surgeons were fulfilled with their operation, while 38.1% (16/42) of the surgeons were not. For patients' satisfaction and surgeons' fulfillment, the preoperative CCAD was significantly greater in patients with unsatisfied outcomes.

DISCUSSION

Clavicle chest cage angle difference could be a reliable predictor for evaluating postoperative shoulder imbalance in AIS patients undergoing selective posterior fusion for Lenke 5C curves. A greater preoperative CCAD was significantly correlated with a postoperative radiographic imbalance of shoulders and dissatisfaction, which will guide spine surgeons in their preoperative planning and in the surgical management of AIS to reduce postoperative shoulder imbalance.

Upright, prone, and supine spinal morphology and alignment in adolescent idiopathic scoliosis

BACKGROUND

Patients with adolescent idiopathic scoliosis (AIS) are usually investigated by serial imaging studies during the course of treatment, some imaging involves ionizing radiation, and the radiation doses are cumulative. Few studies have addressed the correlation of spinal deformity captured by these different imaging modalities, for which patient positioning are different. To the best of our knowledge, this is the first study to compare the coronal, axial, and sagittal morphology of the scoliotic spine in three different body positions (upright, prone, and supine) and between three different imaging modalities (X-ray, CT, and MRI).

METHODS

Sixty-two AIS patients scheduled for scoliosis surgery, and having undergone standard pre-operative work-up, were included. This work-up included upright full-spine radiographs, supine bending radiographs, supine MRI, and prone CT as is the routine in one of our institutions. In all three positions, Cobb angles, thoracic kyphosis (TK), lumbar lordosis (LL), and vertebral rotation were determined. The relationship among three positions (upright X-ray, prone CT, and supine MRI) was investigated according to the Bland-Altman test, whereas the correlation was described by the intraclass correlation coefficient (ICC).

RESULTS

Thoracic and lumbar Cobb angles correlated significantly between conventional radiographs (68° ± 15° and 44° ± 17°), prone CT (54° ± 15° and 33° ± 15°), and supine MRI (57° ± 14° and 35° ± 16°; ICC ≥0.96; P < 0.001). The thoracic and lumbar apical vertebral rotation showed a good correlation among three positions (upright, 22° ± 12° and 11° ± 13°; prone, 20° ± 9° and 8° ± 11°; supine, 16° ± 11° and 6° ± 14°; ICC ≥0.82; P < 0.001). The TK and LL correlated well among three different positions (TK 26° ± 11°, 22° ± 12°, and 17° ± 10°; P ≤ 0.004; LL 49° ± 12°, 45° ± 11°, and 44° ± 12°; P < 0.006; ICC 0.87 and 0.85).

CONCLUSIONS

Although there is a generalized underestimation of morphological parameters of the scoliotic deformity in the supine and prone positions as compared to the upright position, a significant correlation of these parameters is still evident among different body positions by different imaging modalities. Findings of this study suggest that severity of scoliotic deformity in AIS patients can be largely represented by different imaging modalities despite the difference in body positioning.

Reproducibility of thoracic kyphosis measurements in patients with adolescent idiopathic scoliosis

Background

Current surgical treatment for adolescent idiopathic scoliosis (AIS) involves correction in both the coronal and sagittal plane, and thorough assessment of these parameters is essential for evaluation of surgical results. However, various definitions of thoracic kyphosis (TK) have been proposed, and the intra- and inter-rater reproducibility of these measures has not been determined. As such, the purpose of the current study was to determine the intra- and inter-rater reproducibility of several TK measurements used in the assessment of AIS.

Methods

Twenty patients (90% females) surgically treated for AIS with alternate-level pedicle screw fixation were included in the study. Three raters independently evaluated pre- and postoperative standing lateral plain radiographs. For each radiograph, several definitions of TK were measured as well as L1–S1 and nonfixed lumbar lordosis. All variables were measured twice 14 days apart, and a mixed effects model was used to determine the repeatability coefficient (RC), which is a measure of the agreement between repeated measurements. Also, the intra- and inter-rater intra-class correlation coefficient (ICC) was determined as a measure of reliability.

Results

Preoperative median Cobb angle was 58° (range 41°–86°), and median surgical curve correction was 68% (range 49–87%). Overall intra-rater RC was highest for T2–T12 and nonfixed TK (11°) and lowest for T4–T12 and T5–T12 (8°). Inter-rater RC was highest for T1–T12, T1-nonfixed, and nonfixed TK (13°) and lowest for T5–T12 (9°). Agreement varied substantially between pre- and postoperative radiographs. Inter-rater ICC was highest for T4–T12 (0.92; 95% CI 0.88–0.95) and T5–T12 (0.92; 95% CI 0.88–0.95) and lowest for T1-nonfixed (0.80; 95% CI 0.72–0.88).

Conclusions

Considerable variation for all TK measurements was noted. Intra- and inter-rater reproducibility was best for T4–T12 and T5–T12. Future studies should consider adopting a relevant minimum difference as a limit for true change in TK.

Electronic supplementary material

The online version of this article (doi:10.1186/s13013-017-0112-4) contains supplementary material, which is available to authorized users.

Preoperative Magnetic Resonance Imaging Evaluation in Patients with Adolescent Idiopathic Scoliosis

Study Design

Retrospective case series.

Purpose

The purpose of this study was to examine the incidence of neural axis abnormalities and the relevant risk factors in patients with adolescent idiopathic scoliosis (AIS).

Overview of Literature

The use of preoperative magnetic resonance imaging (MRI) to assess the whole spine in patients with idiopathic scoliosis is controversial, and indications for such MRI evaluations have not been definitively established. However, we routinely use whole-spine MRI in patients with scoliosis who are scheduled to undergo surgical correction.

Methods

A total of 378 consecutive patients with presumed AIS who were admitted for spinal surgery were examined for neural axis abnormalities using MRI. To differentiate patients with normal and abnormal MRI findings, the following clinical parameters were evaluated: age, sex, menarcheal status, rotation angle (using a scoliometer), coronal balance, shoulder height difference, and low back pain. We radiographically evaluated curve type, thoracic or thoracolumbar curve direction, curve magnitude and flexibility, apical vertebral rotation, curve length, coronal balance, sagittal balance, shoulder height difference, thoracic kyphosis, and the Risser sign.

Results

Neural axis abnormalities were detected in 24 patients (6.3%). Abnormal MRI findings were significantly more common in males than in females and were associated with increased thoracic kyphosis. However, there were no significant differences in terms of the other measured parameters.

Conclusions

Among the patients with presumed AIS who received preoperative whole-spine MRI, 6.3% had neural axis abnormalities. Males and patients with increased thoracic kyphosis were at a higher risk.

Does a dual attending surgeon strategy confer additional benefit for posterior selective thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis (AIS)? A prospective propensity matching score analysis

BACKGROUND CONTEXT

With an increased cost of adolescent idiopathic scoliosis (AIS) surgery over the past 10 years, improvement of patient safety and optimization of the surgical management of AIS has become an important need. A dual attending surgeon strategy resulted in reduction of blood loss and complication rate.

PURPOSE

This study aimed to investigate the perioperative outcome of posterior selective thoracic fusion in Lenke 1 and 2 AIS patients comparing a single versus a dual attending surgeon strategy.

STUDY DESIGN

A prospective cohort study was carried out.

PATIENT SAMPLE

The study sample comprised 60 patients OUTCOME MEASURE: Operative duration, blood loss, postoperative hemoglobin, need for transfusion, morphine usage, and duration of hospital stay were the outcome measures.

METHODS

A total of 116 patients who underwent posterior selective thoracic fusion from two centers were prospectively recruited. The patients were grouped into Group 1 (single surgeon) and Group 2 (two surgeons). One-to-one matching analysis using "propensity score-matched cohort patient sampling method" was done for age, gender, height, weight, preoperative Cobb angle, number of fusion level, and Lenke classification. The outcome measures included operative duration, blood loss, postoperative hemoglobin, need for transfusion, morphine usage, and duration of hospital stay. This study was self-funded with no conflict of interest.

RESULTS

From 86 patients who were operated by the two surgeons (Group 2), 30 patients were matched with 30 patients who were operated by a single surgeon (Group 1). Group 2 (164.0±25.7 min) has a significantly shorter operation duration (p=.000) compared with Group 1 (257.3±51.4 min). The total blood loss was significantly more (p=.009) in Group 1 (1254.7±521.5 mL) compared with Group 2 (893.7±518.4 mL). There were seven patients (23.3%) in Group 1 who received allogenic blood transfusion (p<.05). The morphine usage and average hospital stay were significantly lower in Group 2, 22.4±10.7 mg and 3.4±0.7 days, respectively (p<.05). In Group 1, there was one patient who developed a superficial wound infection. No other major complications were noted.

CONCLUSIONS

A dual attending surgeon strategy was superior to a single surgeon strategy in posterior selective thoracic fusion in Lenke 1 and 2 AIS patients and will lead to a faster operation, reduced intraoperative blood loss, reduced risk of allogenic transfusion, reduced morphine requirement, and shorter hospital stay.

Maintenance of spontaneous lumbar curve correction following thoracic fusion of main thoracic curves in adolescent idiopathic scoliosis

AIMS

The aims of our study were to provide long-term information on the behaviour of the thoracolumbar/lumbar (TL/L) curve after thoracic anterior correction and fusion (ASF) and to determine the impact of ASF on pulmonary function.

PATIENTS AND METHODS

A total of 41 patients (four males, 37 females) with main thoracic (MT) adolescent idiopathic scoliosis (AIS) treated with ASF were included. Mean age at surgery was 15.2 years (11 to 27). Mean follow-up period was 13.5 years (10 to 18).

RESULTS

For the TL/L curve, the mean curve flexibility evaluated with supine pre-operative bending radiographs was 78.6% (standard deviation 16.5%), with no significant loss of correction observed. On comparing patients with an increase of the TL/L curve increase (> 4º, n = 9, 22%) to those without, significant differences were observed in the correction rate of the MT curve at the final follow-up (p = 0.011), correction loss of the MT curve (p = 0.003) and the proportion of patients who had semi-rigid instrumentation (p = 0.003). Pre-operative percentage predicted forced vital capacity (%FVC) was 80%, dropping to 72% at final follow-up (p < 0.001). The Scoliosis Research Society questionnaire score was not significantly different between patients with and without a TL/L curve increase (p = 0.606). Spontaneous lumbar curve correction (SLCC) was maintained up to 18 years following selective ASF in most patients and demonstrated significant correlation with maintenance of MT curve correction.

CONCLUSION

Maintenance of MT curve correction using rigid instrumentation provided stable SLCC over time. An observed 8% decrease in %FVC indicates that ASF should be reserved for patients with no or only mild pulmonary impairment. Cite this article: Bone Joint J 2016;98-B:997-1002.

The association of lumbar curve magnitude and spinal range of motion in adolescent idiopathic scoliosis: a cross-sectional study

Background

Spinal deformities affect the overall alignment of the spine and thus the vectors of loading on the lumbar region and intervertebral discs. Due to wedging of the disc or vertebrae of unbalanced spinal segments, alignment change may affect the range of motion (ROM) of individual spinal segments or the global spine. This is particularly important in adolescent idiopathic scoliosis (AIS) patients who may suffer from early degeneration, back stiffness and pain. Hence, this study aimed to determine the correlation between spine range of motion (ROM) and adolescent idiopathic scoliosis (AIS) curve magnitude.

Methods

Consecutive recruitment of all AIS patients with Lenke 5 (thoracolumbar/lumbar) curves within one month was performed with ROM assessments in the coronal, sagittal and axial planes using the change in C7-S1 distance on standing upright, active flexion and extension positions, change in finger-floor distance on forward bending position and lateral bending, lateral bending angles, modified Schober’s test, and trunk rotation in seating position. Patients were further stratified into two groups based on their lumbar spine curve magnitude: Group A with curves of 10 to 39 degrees and Group B with 40 degrees or greater. Univariate and multivariate analyses were conducted, with lumbar curve magnitude severity being the dependent variable.

Results

In total, 58 patients (n = 12 males, n = 46 females; mean age: 15.7 years) were recruited. The mean curve magnitudes were 25 ± 6.5 degrees in Group A and 48 ± 10.6 degrees in Group B. Mean axial rotation (Group A: 90 ± 21.7 degree; Group B: 76 ± 19.6 degrees; p = 0.038) and lateral bending ROM (Group A: 67 ± 13.4 degrees; Group B: 58 ± 14.3 degrees; p = 0.045) decreased in more severe curves. These two parameters continued to remain significant irrespective of the curve severity cut-off values.

Conclusions

This is the first study to determine associations between spinal ROM parameters with the lumbar curve magnitude in AIS patients. We found that the coronal curve severity is associated with reduced axial and coronal ROM. This is a platform for future studies assessing lumbar spine biomechanics in AIS and to determine the effects of altered spine motion in this context and its implication in patient management and outcomes.

Asymmetry of the Vertebral Body and Pedicles in the True Transverse Plane in Adolescent Idiopathic Scoliosis: A CT-Based Study

STUDY DESIGN

Cross-sectional.

OBJECTIVES

To quantify the asymmetry of the vertebral bodies and pedicles in the true transverse plane in adolescent idiopathic scoliosis (AIS) and to compare this with normal anatomy.

SUMMARY OF BACKGROUND DATA

There is an ongoing debate about the existence and magnitude of the vertebral body and pedicle asymmetry in AIS and whether this is an expression of a primary growth disturbance, or secondary to asymmetrical loading.

METHODS

Vertebral body asymmetry, defined as left-right overlap of the vertebral endplates (ie, 100%: perfect symmetry, 0%: complete asymmetry) was evaluated in the true transverse plane on CT scans of 77 AIS patients and 32 non-scoliotic controls. Additionally, the pedicle width, length, and angle and the length of the ideal screw trajectory were calculated.

RESULTS

Scoliotic vertebrae were on average more asymmetric than controls (thoracic: AIS 96.0% vs. controls 96.4%; p = .005, lumbar: 95.8% vs. 97.2%; p < .001) and more pronounced around the thoracic apex (95.8%) than at the end vertebrae (96.3%; p = .031). In the thoracic apex; the concave pedicle was thinner (4.5 vs. 5.4 mm; p < .001) and longer (20.9 vs. 17.9 mm; p < .001), the length of the ideal screw trajectory was longer (43.0 vs. 37.3 mm; p < .001), and the transverse pedicle angle was greater (12.3° vs. 5.7°; p < .001) than the convex one. The axial rotation showed no clear correlation with the asymmetry.

CONCLUSIONS

Even in non-scoliotic controls is a degree of vertebral body and pedicle asymmetry, but scoliotic vertebrae showed slightly more asymmetry, mostly around the thoracic apex. In contrast to the existing literature, there is no major asymmetry in the true transverse plane in AIS and no uniform relation between the axial rotation and vertebral asymmetry could be observed in these moderate to severe patients, suggesting that asymmetrical vertebral growth does not initiate rotation, but rather follows it as a secondary phenomenon.

LEVEL OF EVIDENCE

Level 4.

Is the Superior Articular Process a Reliable Landmark for Determining the Transverse Plane Angulation of Thoracic Pedicles in Patients With Adolescent Idiopathic Scoliosis?

PURPOSE

To analyze the usefulness of the superior articular process (SAP) as an external landmark for determining the transverse plane angulation of thoracic pedicles in scoliotic spines.

METHODS

Two investigators reviewed thoracic spine CT scans of 60 patients with adolescent idiopathic scoliosis. The gantry was adjusted to obtain axial images parallel to the superior endplate. Each investigator measured the Cobb angle of the thoracic curve and identified the apical vertebra. This vertebra as well as the vertebrae bordering it superiorly and inferiorly was examined. A line was subtended at a 90° angle to the surface of the SAP, with a starting point at the midpoint of the lateral half of the SAP. It was documented whether the line was contained within the pedicle or breeched it medially or laterally. Breeches were corrected to an ideal projection, and the degree and direction of correction was recorded. Curves of 50°-60° were then compared to curves ≥70°.

RESULTS

Four subjects in our cohort were excluded as a result of inadequate imaging. Of 336 measurements, 89.3% were contained in bone, resulting in a breech rate of 10.7%. A majority of wall violations were on the lateral side (94.4%), with the average degree of correction being 6.1°. Interobserver agreement was calculated to be 95%, 87.5%, and 89.3% for superior, apical, and inferior vertebral measurements, respectively. On further stratification of the patients based on a Cobb angle of 50°-60° and ≥70°, we found that patients with curves ≥70° have a greater incidence of wall breech at the apical vertebra (10% vs. 5.6%) (p = .02).

CONCLUSION

The SAP can serve as a reliable external landmark for determining the transverse plane angulation of thoracic pedicles in scoliotic spines.

LEVEL OF EVIDENCE

Level 3.

National Trends in the Surgical Management of Adolescent Idiopathic Scoliosis: Analysis of a National Estimate of 60,108 Children From the National Inpatient Sample Over a 13-Year Time Period in the United States

STUDY DESIGN

Analysis of Nationwide Inpatient Sample (NIS).

OBJECTIVE

Evaluate evolution of operative treatment of adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Spinal surgery is one of the most rapidly evolving branches of surgery. Changes in AIS operations are incompletely defined.

METHODS

Children (10-18 years) with ICD-9 diagnosis of idiopathic scoliosis who underwent thoracic and/or lumbar spinal fusion identified in the NIS (1998-2011) were analyzed. Population-based utilization rates were calculated from US Census data. Patient demographics, surgical approach, operative techniques, complications during hospitalization, hospital stay length, and charges were analyzed.

RESULTS

60,108 children (46,256 girls, 13,776 boys, 76 gender not specified; average age 14.1 years) were identified. Thoracic fusions were the majority. Number of operations increased over time. For thoracic fusions, posterior operations significantly increased, whereas anterior and anterior/posterior operations decreased significantly. Although anterior operations for lumbar fusions declined, this was not as steep as thoracic. Use of autogenous bone graft (including iliac crest) significantly increased, which mirrored significant decreases in alternative fusion agents. Thoracoplasty significantly decreased, whereas osteotomy significantly increased. The average complication rate was 3.7%. Rates of blood transfusions, infection, and neural injury did not differ significantly from 1998 to 2011. Device-related complications increased significantly over time. Average lengths of hospital stay decreased significantly, whereas average total hospital charges increased significantly.

CONCLUSIONS

In a representative sample of the US population from 1998 to 2011, operative approaches and techniques for AIS significantly changed. Anterior procedure is rarely performed for thoracic curves; lumbar curves continue to be treated with anterior and posterior approaches. Osteotomy and autogenous bone graft increased, while thoracoplasty decreased. Overall complication rates remain stable, whereas hospital lengths of stays decreased and charges increased.

Position of the major curve influences asymmetrical trunk kinematics during gait in adolescent idiopathic scoliosis

BACKGROUND AND PURPOSE

Adolescent idiopathic scoliosis (AIS) is a structural, lateral curvature with rotation of the spine that develops around puberty. The influence of this spinal deformity on three-dimensional trunk movements during gait has not yet been elucidated. The aim of this study was to determine the influence of spinal curve pattern (single thoracic curve vs. single lumbar curve) on trunk kinematics during gait.

METHODS

Twenty-two patients with a single thoracic curve (Lenke type 1) and 17 patients with a single lumbar curve (Lenke type 5) were included in this study. Trunk symmetry in the sagittal, coronal, and transverse planes during gait was evaluated using an optoelectronic motion capture system.

RESULTS

In the type 1 group, the trunk was significantly rotated towards the concave side in the transverse plane during gait (mean difference of transverse rotation angle between concave side load and the convex side load, 8.8±0.6°, p<0.01). In the type 5 group, the trunk was significantly rotated towards the convex side in the coronal plane throughout the stance phase of gait (mean difference of coronal inclination angle, 1.9±0.3°, p<0.05).

CONCLUSIONS

The AIS patients with a single thoracic curve showed asymmetrical trunk movement in the transverse plane, and patients with a single lumbar curve showed asymmetrical trunk movement in the coronal plane. These results indicate that the spinal curve pattern influenced trunk kinematics, and suggest that the global postural control strategy of patients with AIS differs according to the curve pattern.

Motivations for Compliance With Bracing in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To determine motivations for compliance with bracing among female patients with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Bracing prevents the need for surgery for the majority of girls with AIS with curves of 20° to 40° and 2 or more years of growth remaining. The main obstacle to success is compliance. The factors that either promote or impede compliance previously have not been fully clarified.

METHODS

Participants were females 10 to 16 years of age who were prescribed a brace to be worn 16 hours per day for AIS. Each completed a "Scoliosis Compliance Questionnaire" composed of the SRS-22r and five original sections focused on patients' attitudes to scoliosis, situations in which they found wearing the brace to be most and least difficult, factors that motivate brace wear, and interventions that could potentially improve compliance.

RESULTS

Thirty-nine subjects completed the study, mean age 13 years (range 11-15 years), at a mean of 15.4 months (range 4-39 months) of brace wear at the time of recruitment. More than 90% of patients stated that their main motivations for compliance were the desire to avoid surgery and to prevent curve progression. Compliance was most challenging during the summer and while at school. Many patients reported pain and skin irritation in the brace. The majority reported they would likely improve their hours of wear if they were able to communicate with a peer in the same situation. SRS-22r scores were similar to those of healthy adolescents.

CONCLUSIONS

The most important influences promoting brace wear are the patient's desire to avoid surgery and to prevent curve progression. Peer support potentially may improve compliance.

LEVEL OF EVIDENCE

Level III.

A software program to measure the three-dimensional length of the spine from radiographic images: Validation and reliability assessment for adolescent idiopathic scoliosis

BACKGROUND AND OBJECTIVE

The aim of this study was to validate a new program which aims at measuring the three-dimensional length of the spine's midline based on two calibrated orthogonal radiographic images. The traditional uniplanar T1-S1 measurement method is not reflecting the actual three dimensional curvature of a scoliotic spine and is therefore not accurate. The Spinal Measurement Software (SMS) is an alternative to conveniently measure the true spine's length.

METHODS

The validity, inter- and intra-observer variability and usability of the program were evaluated. The usability was quantified based on a subjective questionnaire filled by eight participants using the program for the first time. The validity and variability were assessed by comparing the length of five phantom spines measured based on CT-scan data and on radiographic images with the SMS. The lengths were measured independently by each participant using both techniques.

RESULTS

The SMS is easy and intuitive to use, even for non-clinicians. The SMS measured spinal length with an error below 2 millimeters compared to length obtained using CT scan datasets. The inter- and intra-observer variability of the SMS measurements was below 5 millimeters.

CONCLUSIONS

The SMS provides accurate measurement of the spinal length based on orthogonal radiographic images. The software is easy to use and could easily integrate the clinical workflow and replace current approximations of the spinal length based on a single radiographic image such as the traditional T1-S1 measurement.

Effect of physical therapy scoliosis specific exercises using breathing pattern on adolescent idiopathic scoliosis

[Purpose] This study was performed to confirm physical therapy scoliosis specific exercises on adolescent idiopathic scoliosis patients. [Subject and Methods] A 15-year-old male middle school student with scoliosis. Cobb's angle, angle of rotation of the spine, and breathing pattern were measured before and after 8 weeks training. [Results] After 8 weeks training, Cobb's angle, angle of rotation of the spine, and breathing pattern were improved better. [Conclusion] These results indicate that physical therapy scoliosis specific exercises improves scoliosis curves and could provide an effective intervention and management of scoliosis.

Complications following spine fusion for adolescent idiopathic scoliosis

Complications following spine fusion for adolescent idiopathic scoliosis can be characterized as either intra-operative or post-operative. The most serious and feared complication is neurologic injury, both in the intra- and post-operative period. Other intra-operative complications include dural tears and ophthalmologic or peripheral nerve deficits, which may be related to positioning. Among the most common post-operative complications are surgical site infection, venous thromboembolism, gastrointestinal complications, and implant-related complications. Significant blood loss requiring transfusion, traditionally considered a known sequelae of spine fusion, is now being recognized as a "complication" in large national databases. Pediatric spine surgeons who care for patients with AIS must be thoroughly familiar with all potential complications and their management.

Comparison of Consecutive, Interval, and Skipped Pedicle Screw Techniques in Moderate Lenke Type 1 Adolescent Idiopathic Scoliosis

OBJECTIVE

To compare perioperative, radiographic, and Scoliosis Research Society-22 (SRS-22) outcomes of consecutive, interval, and skipped pedicle screw techniques in patients with moderate Lenke type 1 adolescent idiopathic scoliosis (AIS).

METHODS

We retrospectively reviewed 65 consecutive moderate Lenke type 1 AIS patients at a single institution using all-pedicle screw constructs, with a minimum of 2 years of follow-up. In the consecutive group (C group, n = 22), pedicle screws were instrumented at consecutive levels bilaterally. In the interval group (I group, n = 18), pedicle screws were placed at every level on the concave side while skipping levels on the convex side. In the skipped group (S group, n = 25), pedicle screws were instrumented by skipping levels bilaterally. Perioperative, radiographic, and SRS-22 measurements were analyzed with a 1-way analysis of variance.

RESULTS

No significant differences were found in length of hospital stay, fused levels, coronal correction, and SRS-22 scores among the 3 groups. Increased surgery time was found in the C group compared with the I and S groups (P = 0.001 and P = 0.005, respectively). Decreased blood loss and blood transfusions were found in the S group compared with the C group (P = 0.04 and P = 0.047, respectively). Decreased implant costs were found in the S group compared with the C and I groups (P < 0.001 and P = 0.03, respectively).

CONCLUSIONS

Consecutive, interval, and skipped pedicle screw techniques all provide satisfactory deformity correction and SRS-22 outcomes with few complications. With better perioperative outcomes, interval and skipped pedicle screw techniques are the more cost-effective options for patients with moderate Lenke type 1 AIS.

Minimally invasive surgery in the treatment of adolescent idiopathic scoliosis: A literature review and meta-analysis

BACKGROUND CONTEXT

Spinal fusion surgery for scoliosis can be performed using a traditional open approach, or by following a minimally invasive approach. Minimally invasive surgery (MIS) is associated with theoretical advantages, such as reduced blood loss and a shorter hospital stay, yet there is no consensus in the literature with regard to the best treatment approach for adolescent idiopathic scoliosis (AIS).

PURPOSE

To assess the clinical outcomes of patients with AIS treated with either an open or minimally invasive approach.

STUDY DESIGN

Systematic review and meta-analysis of English-language studies for the treatment of adolescent idiopathic scoliosis.

PATIENT SAMPLE

Pooled results from level 1 and 2 studies.

METHODS

We carried out a systematic literature search of EMBASE and MEDLINE, identifying studies investigating MIS in the treatment of AIS. Percentages of curvature correction were pooled and analysed.

RESULTS

The literature search returned 50 articles, of which we determined 4 studies to be relevant. The pooled percentage curve correction across these groups was 62.05% for the MIS group and 70% for the open surgery group. Although these data are significant (p = 0.001), the available studies are of variable quality, and sample sizes small.

CONCLUSIONS

Patients with adolescent idiopathic scoliosis can be managed with either a traditional open approach or a minimally invasive approach. The data suggests that open surgery offers an advantage in terms of curve correction, compared to minimally invasive surgery, however more investigation (in the form of robust randomized control trials) is needed before conclusive clinical suggestions can be recommended.

The Spinopelvic Geometry in Different Lenke Curve Types of Adolescent Idiopathic Scoliosis

BACKGROUND

The Lenke classification is well established in differentiation of curve types in adolescent idiopathic scoliosis (AIS) and guides selection of fusion levels. However, to date, it has neglected the spinopelvic parameters that have been associated with compensatory mechanisms in balancing the human erect posture and adjacent segment problems after spinal fusion. The aim of this study was to investigate spinopelvic parameters in different types of AIS curves.

MATERIAL AND METHODS

Preoperative whole-spine radiographs from 100 patients with AIS were reviewed and the curves were classified according to Lenke. In addition, sagittal spinopelvic parameters (pelvic incidence, sacral slope, pelvic tilt) were measured and compared between different curve types and to normal population values.

RESULTS

The spinopelvic balance was not statistically distinguishable in different Lenke curve types. Slight differences of the spinopelvic balance, compared with normal population values, were found in AIS Lenke Type 5 and 6 curves (major curve at the lumbar/thoracolumbar region) with a pelvic incidence of 44° ± 8° (norm 49°), sacral slope of 34° ± 7° (norm 41°), and pelvic tilt of 10° ± 7° (norm 8°).

CONCLUSION

Overall, the variances of spinopelvic parameters in different AIS curve types do not seem statistically large enough for a potential clinical relevance. However, the sacrum is more verticalized in AIS curves with major curves located in the lumbar/thoracolumbar region. It remains to be investigated whether such a verticalized sacrum might be a compensatory mechanism to keep the whole spine balanced and if it reverses with correction of the scoliosis.

How does implant distribution affect 3D correction and bone-screw forces in thoracic adolescent idiopathic scoliosis spinal instrumentation?

BACKGROUND

Optimal implant densities and configurations for thoracic spine instrumentation to treat adolescent idiopathic scoliosis remain unknown. The objective was to computationally assess the biomechanical effects of implant distribution on 3D curve correction and bone-implant forces.

METHODS

3D patient-specific biomechanical spine models based on a multibody dynamic approach were created for 9 Lenke 1 patients who underwent posterior instrumentation (main thoracic Cobb: 43°-70°). For each case, a factorial design of experiments was used to generate 128 virtual implant configurations representative of existing implant patterns used in clinical practice. All instances except implant configuration were the same for each surgical scenario simulation.

FINDINGS

Simulation of the 128 implant configurations scenarios (mean implant density=1.32, range: 0.73-2) revealed differences of 2° to 10° in Cobb angle correction, 2° to 7° in thoracic kyphosis and 2° to 7° in apical vertebral rotation. The use of more implants, at the concave side only, was associated with higher Cobb angle correction (r=-0.41 to -0.90). Increased implant density was associated with higher apical vertebral rotation correction for seven cases (r=-0.20 to -0.48). It was also associated with higher bone-screw forces (r=0.22 to 0.64), with an average difference between the least and most constrained instrumentation constructs of 107N per implant at the end of simulated instrumentation.

INTERPRETATION

Low-density constructs, with implants mainly placed on the concave side, resulted in similar simulated curve correction as the higher-density patterns. Increasing the number of implants allows for only limited improvement of 3D correction and overconstrains the instrumentation construct, resulting in increased forces on the implants.

The effect of scoliotic deformity on spine kinematics in adolescents

BACKGROUND

While adolescent idiopathic scoliosis (AIS) produces well characterized deformation in spinal form, the effect on spinal function, namely mobility, is not well known. Better understanding of scoliotic spinal mobility could yield better treatment targets and diagnoses. The purpose of this study was to characterize the spinal mobility differences due to AIS. It was hypothesized that the AIS group would exhibit reduced mobility compared to the typical adolescent (TA) group.

METHODS

Eleven adolescents with right thoracic AIS, apices T6-T10, and eleven age- and gender-matched TAs moved to their maximum bent position in sagittal and coronal plane bending tasks. A Trakstar (Ascension Technologies Burlington, VT) was used to collect position data. The study was approved by the local IRB. Using MATLAB (MathWorks, Natick, MA) normalized segmental angles were calculated for upper thoracic (UT) from T1-T3, mid thoracic (MT) from T3-T6, lower thoracic (LT) from T6-T10, thoracolumbar (TL) from T10-L1, upper lumbar (UL) from L1-L3, and thoracic from T1-L1 by subtracting the standing position from the maximum bent position and dividing by number of motion units in each segment. Mann Whitney tests (α = 0.05) were used to determine mobility differences.

RESULTS

The findings indicated that the AIS group had comparatively increased mobility in the periapical regions of the spine. The AIS group had an increase of 1.2° in the mid thoracic region (p = 0.01) during flexion, an increase of 1.0° in the mid thoracic region (p = 0.01), 1.5° in the thoracolumbar region (p = 0.02), and 0.7° in thoracic region (p = 0.04) during left anterior-lateral flexion, an increase of 6.0° in the upper lumbar region (p = 0.02) during right anterior-lateral flexion, and an increase of 2.2° in the upper lumbar region during left lateral bending (p < 0.01).

CONCLUSIONS

Participants with AIS did not have reduced mobility in sagittal or coronal motion. Contrarily, the AIS group often had a greater mobility, especially in segments directly above and below the apex. This indicates the scoliotic spine is flexible and may compensate near the apex.

Impact of Rotation Correction after Brace Treatment on Prognosis in Adolescent Idiopathic Scoliosis

Study Design

Level 4 retrospective review.

Purpose

Brace treatment is the standard nonoperative treatment for adolescent idiopathic scoliosis (AIS). Rotation correction is also important, because AIS involves a rotation deformity. The purpose of this study was to evaluate the impact of rotation correction after Osaka Medical College (OMC) brace treatment on clinical outcomes in AIS.

Overview of Literature

Brace treatment has a significant effect on the progression of AIS. However, few reports have examined rotation correction after brace treatment.

Methods

A total of 46 patients who wore the OMC brace were retrospectively reviewed. The curve magnitude was determined according to the Cobb method, and the rotation angle of the apical vertebrae was measured by the modified Nash-Moe method. Based on the difference in the rotation angle before and after the initial brace treatment, patients were divided into two groups. Group A (n=33) was defined as no change or improvement of the rotation angle; group B (n=13) was defined as deterioration of the rotation angle. If the patients had curve or rotation progression of 5° or more at skeletal maturity, or had undergone surgery, the treatment was considered a failure.

Results

Differences of rotation angle between before and after the initial brace treatment were 2°±2° in group A and –3°±2° in group B (p<0.001). The rates of treatment failure were 42% in group A and 77% in group B (p<0.05). This study included 25 patients with Lenke type 1 (54%). Group A (24%) with Lenke type 1 also had a significantly better success rate of brace treatment than group B (75%) (p<0.05).

Conclusions

Insufficient rotation correction increased brace treatment failure. Better rotation correction resulted in a higher success rate of brace treatment in patients with Lenke type 1.

Plasticity of vertebral wedge deformities in skeletally immature patients with adolescent idiopathic scoliosis after posterior corrective surgery

Background

Vertebral bodies in patients with adolescent idiopathic scoliosis (AIS) usually have frontal wedge deformities. However, the plasticity of the deformed vertebrae in skeletally immature patients is unknown. The purpose of our study was to clarify the plasticity of vertebral deformities in skeletally immature patients with AIS by using in vivo three-dimensional (3D) analysis.

Methods

Ten female patients with AIS (mean age, 12.2 years; three patients, Lenke type 1; five patients, type 2; two patients, type 5) who underwent posterior fusion and whose Risser grade was ≤3 at surgery were included. Using computed tomography images (0.625-mm slice thickness) obtained 1 week and 1 year postoperatively, a total of seventy-three 3D bone models of vertebrae was made. The 3D bone models were made between the upper and lower end vertebrae within the main thoracic curve for patients with Lenke types 1 and 2 scoliosis, whereas they were made within the thoracolumbar/lumbar curve in patients with Lenke type 5 scoliosis. The height of the concave and convex sides in the anterior, middle and posterior parts of the vertebral bodies was measured using the original digital viewer, and the vertebral height ratio (VHR: concave/convex) was calculated. VHRs at 1 week and 1 year postoperatively were compared using the Wilcoxson signed-rank test. Differences were considered statistically significant at p < 0.05.

Results

VHR of the end vertebrae (n = 20) did not change postoperatively for any parts of the vertebral bodies. VHR of the vertebrae in the apical region (n = 28) also remained unchanged postoperatively. In contrast, VHR of the other vertebrae (n = 25) increased significantly in the anterior part postoperatively (from 0.938 to 0.961, p = 0.006).

Conclusions

The wedge deformity of vertebral bodies showed a reshaping potential towards a symmetrical configuration in the region other than end and apex, although no plasticity of the vertebrae was observed in the apical region even in skeletally immature patients with AIS.

[RELATED FACTORS ANALYSIS OF DISTAL ADDING-ON PHENOMENON IN MAJOR THORACIC CURVE AFTER POSTERIOR SELECTIVE FUSION]

OBJECTIVE

To identify the prevalence of distal adding-on phenomenon after posterior selective fusion in type Lenke 1A idiopathic scoliosis, to analyze its risk factors so as to find the reasonable choice for lowest instrumented vertebra (LIV).

METHODS

A retrospective study was made on the clinical data of 43 patients with type Lenke 1A idiopathic scoliosis undergoing posterior selection fusion with pedicle screw instrumentation between July 2011 and December 2015. There were 15 males and 28 females, aged 12-18 years (mean, 16 years). The preoperative Cobb angle was (50.1±11.3)°. The anteroposterior and lateral radiographs were taken at preoperation, immediate after operation, and last follow-up to measure the radiographic parameters. Forty-three patients were divided into adding-on group and control group according to whether or not the occurrence of distal adding-on phenomenon on anteroposterior radiographs of the spine at last follow-up. All the factors that maybe cause distsal adding-on were evaluated by statistical analysis.

RESULTS

The patients were followed up 12-50 months (mean, 26.5 months). At last follow-up, distal adding-on was observed in 10 of 43 patients (23.3%), including 2 males (13.3%) and 8 females (28.6%). Univariate analyses showed following several factors associated with adding-on:preoperative lumbar flexibility, preoperative pelvic tilt in coronal plane, preoperative LIV+1 deviation from center sacral vertical line, L₄ subtype, the difference between LIV and last touching vertebra (LTV) (LIV-LTV), the difference between LIV and lower end vertebra (LEV) (LIV-LEV), and the difference between LIV and stable vertebra (SV) (LIV-SV). The risk factors above were brought into Logistic regression model, the results showed that preoperative LIV+1 deviation (deviation>10 mm, odds ratio=10.812, P=0.026), LIV-LTV (LIV-LTV<1, odds ratio=9.017, P=0.04), and L₄ subtype (1A-R, odds ratio=9.744, P=0.047) were significantly associated with adding-on.

CONCLUSIONS

Preoperative LIV+1 deviation of >10 mm, L₄ subtype (1A-R) and LIV-LTV of <1 are independent predictive factors of adding-on after surgery. As high risk of adding-on was closely related with the incorrect fusion level, it plays an important role for surgeons to decide the level of the fusion before surgery thoroughly. The LIV should be extended at least to LTV+1 to avoid adding-on phenomenon.

Assessment of Coronal Radiographic Parameters of the Spine in the Treatment of Adolescent Idiopathic Scoliosis

BACKGROUND

To determine the most important preoperative factors that affect postoperative coronal parameters of scoliotic curves.

METHODS

All Adolescent Idiopathic Scoliosis (AIS) patients included in the study were classified according to Lenke and King Classification. The fusion levels were selected according to the rigidity of the existing curves (correction less than 50%), tilt of T1 and shoulders, sagittal angle of the curves and with considering stable and neutral end vertebra. The radiographic coronal parameters: shoulders tilt angle, iliolumbar angle and coronal balance were measured in all patients before, after, and in the last follow-up visit.

RESULTS

One hundred twenty patients after mean of 25 months follow-up (18-40 months) were included in the study. Before operation, abnormal coronal balance (more than 2 cm shift) was noticed in 46 patents (38%) and in the last visit, was noted in 22 patients (18%). Multivariate regression analysis revealed a significant predictive value of the preoperative coronal balance on the last visit coronal balance (P value=0.01).

CONCLUSION

Preoperative coronal balance is very important to make a balanced spine after surgery. Other parameters like Lenke classification or main thoracic overcorrection did not affect postoperative coronal decompensation.

It's not just the big kids: both high and low BMI impact bracing success for adolescent idiopathic scoliosis

PURPOSE

Bracing is a common treatment for patients with adolescent idiopathic scoliosis (AIS) and is recommended for most skeletally immature patients with a curve of 25-45° in order to prevent or delay curve progression. The aim of this study was to determine at which body habitus orthotic management for AIS becomes less effective. We hypothesize that overweight children are more likely to fail brace treatment.

METHODS

This was a retrospective cohort study involving consecutive patients with AIS treated with a thoracolumbosacral orthosis at a large pediatric tertiary care center. Patients were divided into three groups based on BMI: (1) high-BMI group (BMI >85th percentile); (2) low-BMI group (BMI <20th percentile); (3) mid-BMI group (BMI 20th-85th percentile). Successful orthotic treatment was defined as an increase in the primary curve of <5°, prevention of progression past 45°, and avoidance of surgery.

RESULTS

The study cohort comprised 182 patients with a mean age of 12.5 years at brace prescription and a mean follow-up of 2 years. Compared to the mid-BMI group, high- and low-BMI patients were significantly more likely to fail orthotic management. The association between high-BMI and orthotic failure disappeared when compliance and in-brace correction were taken into account, but the association between low-BMI and each poor outcome remained significant.

CONCLUSIONS

Based on our results, children on either end of the BMI spectrum are more likely to fail brace treatment for scoliosis than their mid-BMI counterparts. In high-BMI patients, this appears to be in large part attributable to an inadequacy of in-brace curve correction as well as to poorer brace compliance, while a low BMI appears to be an independent risk factor for brace failure.

Adolescent idiopathic scoliosis and back pain

This broad narrative review addresses the relationship between adolescent idiopathic scoliosis (AIS) and back pain. AIS can be responsible for low back pain, particularly major cases. However, a linear relationship between back pain and the magnitude of the deformity cannot be expected for any individual patient. A large number of juvenile patients can remain pain-free. The long-term prognosis is rather benign for many cases and thus a tailored approach to the individual patient seems mandatory. The level of evidence available does not allow stringent recommendations for any of the disorders included in this review.

Incidence of cancer in adolescent idiopathic scoliosis patients treated 25 years previously

PURPOSE

To report the incidence of cancer in a cohort of adolescent idiopathic scoliosis (AIS) patients treated 25 years previously.

METHODS

215 consecutive AIS patients treated between 1983 and 1990 were identified and requested to return for clinical and radiographic examination. The incidence of cancer was determined through chart review and follow-up interviews. Using the original radiographic log file that included patient position, mAs, kV and the total number of X-rays taken, a radiation physicist calculated the total radiation dose during treatment and follow-up adjusted for BMI and sex.

RESULTS

From the original cohort of 215 consecutive AIS patients, radiation information was available in 211 of the patients, and medical charts were available in 209 AIS patients. 170 (83 %) of the 205 AIS patients participated in the follow-up study with questionnaires. The calculated mean total radiation exposure was 0.8-1.4 mSV per examination and 2.4-5.6 mSv/year. An average of 16 radiographs were taken during the treatment period. Nine AIS patients developed cancer, mostly breast (3) and endometrial (4). The AIS patients had a relative risk of 4.8 (CI 2.3-5.8, p < 0.000) for developing cancer compared to the normal Danish population.

CONCLUSIONS

The overall cancer rate in this AIS cohort was 4.3 % which is five times higher than compared to the age-matched Danish population, and endometrial and breast cancer was most frequent. The radiation dose applied to the patients in this study, is comparable to modern equipment. This is to our knowledge the first study to report increased rates of endometrial cancers in a cohort of AIS patients, and future attention is needed to reduce the radiation dose distributed to the AIS patients both pre-operatively and during surgery.

Correlation analysis between change in thoracic kyphosis and multilevel facetectomy and screw density in main thoracic adolescent idiopathic scoliosis surgery

BACKGROUND CONTEXT

Controversy exists regarding the effects of multilevel facetectomy and screw density on deformity correction, especially thoracic kyphosis (TK) restoration in adolescent idiopathic scoliosis (AIS) surgery.

PURPOSE

This study aimed to evaluate the effects of multilevel facetectomy and screw density on sagittal plane correction in patients with main thoracic (MT) AIS curve.

STUDY DESIGN

A retrospective correlation and comparative analysis of prospectively collected, consecutive, non-randomized series of patients at a single institution was undertaken.

PATIENT SAMPLE

Sixty-four consecutive patients with Lenke type 1 AIS treated with posterior correction and fusion surgery using simultaneous double-rod rotation technique were included.

OUTCOME MEASURES

Patient demographics and preoperative and 2-year postoperative radiographic measurements were the outcome measures for this study.

METHODS

Multiple stepwise linear regression analysis was conducted between change in TK (T5-T12) and the following factors: age at surgery, Risser sign, number of facetectomy level, screw density, preoperative main thoracic curve, flexibility in main thoracic curve, coronal correction rate, preoperative TK, and preoperative lumbar lordosis. Patients were classified into two groups: TK<15° group defined by preoperative TK below the mean degree of TK for the entire cohort (<15°) and the TK≥15° group, defined by preoperative TK above the mean degree of kyphosis (≥15°). Independent sample t tests were used to compare demographic data as well as radiographic outcomes between the two groups. There were no study-specific biases related to conflicts of interest.

RESULTS

The average preoperative TK was 14.0°, which improved significantly to 23.1° (p<.0001) at the 2-year final follow-up. Greater change in TK was predicted by a low preoperative TK (p<.0001). The TK <15° group showed significant correlation between change in TK and number of facetectomy level (r=0.492, p=.002). Similarly, significant correlation was found between change in TK and screw density (r=0.333, p=.047). Conversely, in the TK ≥15° group, correlation was found neither between change in TK and number of facetectomy level (r=0.047, p=.812), nor with screw density (r=0.030, p=.880). Furthermore, in patients with preoperative TK<15°, change in TK was significantly correlated with screw density at the concave side (r=0.351, p=.036) but not at the convex side (r=0.144, p=.402).

CONCLUSIONS

In patients with hypokyphotic thoracic spine, significant positive correlation was found between change in TK and multilevel facetectomy or screw density at the concave side. This indicates that in patients with AIS who have thoracic hypokyphosis as part of their deformity, the abovementioned factors must be considered in preoperative planning to correct hypokyphosis.

Comparison between harvesting and preserving the spinous process for adolescent idiopathic scoliosis

BACKGROUND

Spinous process has been routinely resected during posterior fusion of adolescent idiopathic scoliosis for fusion bed preparation and local autologous bone graft supplement. However, spinous process serves as an important structure in posterior ligament complex and was the anchorage of paraspinal muscle groups. With the development of pedicle screws instrumentation and the potential fusion ability in children, the need for resecting spinous process in this procedure could be further investigated. The purpose of this study was to compare the fusion rates, surgical outcomes and complications between harvesting and preserving the spinous process in posterior fusion of adolescent idiopathic scoliosis.

METHODS

From January 2003 to December 2008, 104 consecutive adolescent idiopathic scoliosis patients underwent primary posterior fusion with local autologous bone grafts and following for a minimum of 24 months were reviewed. The patients were divided into a harvesting group (n = 61) with the spinous process harvested, and a preserving group (n = 43) with the spinous process preserved. Blood loss, radiographic assessments, and clinical outcomes were compared between the two groups.

RESULTS

There were no significant differences in duration of surgery and peri-operative blood transfusion between the two groups. However, blood loss was statistically greater (983 ± 446 ml vs. 824 ± 361 ml; p = 0.048) and duration of hospitalization was statistically longer (7.4 ± 1.0 days vs. 6.8 ± 0.8 days; p = 0.003) in the harvesting group. The pre- and post-operative structural curves, correction rates, sagittal profile and loss of corrections were similar in both groups. Based on radiographic evaluation, the incidences of pseudoarthrosis were similar in both groups (3/61 vs. 2/43; p = 0.95). The incidence of prescribing pain medication for back discomfort during follow-up was statistically higher in the harvesting group (16/61 vs. 4/43; p = 0.03).

CONCLUSIONS

The surgical outcomes and fusion rates between harvesting and preserving the spinous process were comparable. Resecting the spinous process as local autologous bone graft may not be necessary in posterior fusion for adolescent idiopathic scoliosis patients.

The effect of sublaminar wires on the rib hump deformity during scoliosis correction manoeuvres

INTRODUCTION

During thoracic curve correction, the tightening of the sublaminar wires through concavity creates a medial and a dorsal translation of the spine. However, little is known about the effect of the sublaminar wires on the axial plane.

METHODS

This is prospective case series analysis of 30 consecutive surgical patients with main thoracic adolescent idiopathic scoliosis. All of the patients were fused with hybrid instrumentation (apical concavity-sublaminar wires) and differential rod contouring (over-kyphosis concavity/under-kyphosis convexity). The degrees of the rib hump were measured with a scoliometer placed at the apex of the deformity at five different times: (1) preoperatively through the Adam's test, and during surgery (sterilised scoliometer), (2) with the patient lying prone, (3) after the Ponte osteotomies, (4) after the apical sublaminar tightening, and (5) after convexity apical derotation and compression manoeuvres.

RESULTS

(1) Preoperatively, the Adam's test was 16.3° ± 4.6. (2) Lying prone and under general anaesthesia, it decreased to 11.4° ± 3.9. (3) After exposure and Ponte osteotomies, it was 7.1° ± 4. (4) After the wire tightening, it was 10.8° ± 4.7. (5) After the convexity manoeuvres, it was 4.8° ± 3.7. The degrees of the rib hump final correction were 11.6° ± 4 (70 % correction). The tightening of the sublaminar wires increased the rib hump by 3.5°.

CONCLUSIONS

The sublaminar wire tightening towards the concave rod seemed to create an effect opposite of the desired effect, increasing the apical rotation and the thoracic rib hump deformity. Convexity manoeuvres (apical screw derotation and compression) are necessary and must be coupled with an under-bending of the convex rod to neutralise this effect.

An exploration of information exchange by adolescents and parents participating in adolescent idiopathic scoliosis online support groups

Background

Research indicates that healthcare providers frequently fail to adequately address patients’ health information needs. Therefore, it is not surprising that patients or parents of a sick child are seeking health information on the internet, in particular in online support groups (OSGs). In order to improve our understanding of the unmet health information needs of families dealing with adolescent idiopathic scoliosis (AIS), this study assessed and compared the types of information that adolescents and parents are seeking in OSGs.

Methods

This study used two publicly accessible AIS-related OSGs on the National Scoliosis Foundation (NSF) website that targeted those who are receiving brace treatment and those under observation without treatment. Information exchanges were coded as providing or seeking information. Types of information being exchanged were categorized into several AIS-specific and brace-specific categories. Through a review of over 8,000 messages, 305 adolescents with AIS and 300 parents of a child with AIS were identified and categorized based on stage of illness/treatment. One message from each individual was randomly selected and coded for analysis.

Results

There were significantly more (p < 0.001) parents that had a recently diagnosed child compared to recently diagnosed adolescents participating in the AIS-related OSGs, whereas there were significantly more (p = 0.004) adolescents that experienced brace treatment compared to parents of a child that experienced brace treatment. The most frequent information exchanged by adolescents and parents was AIS-related concerns regarding causes, diagnosis, and progression of the condition. However, compared to adolescents, parents exchanged this AIS-related information significantly more (p < .001) in their posts. Finally, compared to parents, adolescents exchanged significantly more information about appearance-related concerns regarding both AIS-related deformity (p < 0.002) and wearing a brace (p < 0.001).

Conclusion

Families dealing with AIS are participating in OSGs to exchange information, in particular information related to the condition and to treatment. This study found similarities and differences regarding how information was exchanged (providing or seeking) and regarding frequency and types of information exchanged. Knowledge of these similarities and differences may be useful for improving health communication in the healthcare setting, at home, and for development and improvement of AIS-related website support.

Psychometric validation of the EuroQoL 5-Dimension 5-Level (EQ-5D-5L) in Chinese patients with adolescent idiopathic scoliosis

Background

Scoliosis is a common spinal deformity that occurs often during adolescence. Previous studies suggested that adolescent idiopathic scoliosis (AIS) patients can have various aspects of their lives being affected, due to disease presentation and/or treatment received. It is important to define a reliable instrument based on which the affected patients’ health-related quality of life can be assessed. This study aims to assess the validity, reliability and sensitivity of the EuroQoL 5-dimension 5-level (EQ-5D-5L) in Chinese patients with AIS.

Methods

Adolescent idiopathic scoliosis patients of Chinese descent were prospectively recruited to complete both the traditional Chinese versions of the EQ-5D-5L and the refined Scoliosis Research Society-22 (SRS-22r) questionnaires. Patients’ demographic profiles and corresponding clinical parameters including treatment modalities, spinal curve pattern and magnitude, and duration of bracing were recorded. Telephone interviews were then conducted at least two weeks later for the assessment of test-retest reliability. Statistical analysis was performed: construct validity of the EQ-5D-5L domains were assessed using Spearman’s correlation test against the SRS-22r; whereas intra-class correlation coefficient (ICC) was used to assess the test-retest reliability, and agreement over the test-retest period was expressed in percentages. Also, the sensitivity of the EQ-5D-5L in differentiating various clinical known groups was determined by effect size, independent t-test and analysis of variance.

Results

A total of 227 AIS patients were recruited. Scores of domains of the EQ-5D-5L correlated significantly (r: 0.57-0.74) with the scores of the SRS-22r domains that were intended to measure similar constructs, supporting construct validity. The EQ-5D-5L domain responses and utility scores showed good test-retest reliability (ICC: 0.777; agreement: 76.4 -98.1 %). Internal consistency was good (Cronbach’s α: 0.78) for the EQ-5D-5L utility score. The EQ-5D-5L utility score was sensitive in detecting differences between subjects who had different treatment modalities and bracing duration, but not for curve pattern and its magnitude.

Conclusions

The EQ-5D-5L is found to be a valid, reliable and sensitive measure to assess the health-related quality of life in Chinese AIS patients. This potentiates the possibility of utilizing the EQ-5D-5L to estimate AIS patients’ health-related quality of life, based on which the outcome of various treatment options can eventually be evaluated.

Electronic supplementary material

The online version of this article (doi:10.1186/s13013-016-0083-x) contains supplementary material, which is available to authorized users.

Fifteen to twenty-five year functional outcomes of twenty-two patients treated with posterior Cotrel-Dubousset type instrumentation: a limited but detailed review of outcomes

Background

Long-term outcomes of patients undergoing extensive fusions for adolescent idiopathic scoliosis (AIS) have conflicting results. Moskowitz found uninstrumented scoliosis fusion patients had similar back pain as a normal age matched population. Recently, long-term outcomes of patients with Harrington rod instrumentation were reviewed and found similar functional outcome scores to non-scoliosis patients, with trending toward worse outcomes when fusions extended to L4. Our study examined long-term functional outcomes of patients treated with Cotrel-Dubousset (CD) instrumentation and determined whether distal level of instrumented fusion (L4 and L5) correlate with increased back pain or lower functional level.

Methods

Retrospective review of AIS surgeries from 1986 to 1996 was undertaken. Patient demographics and surgical data were collected via case-note audit. Patients were contacted and asked to complete a series of functional outcome questionnaires including visual analog scales (VAS) for pain, Short-Form 36 (SF-36), Scoliosis Research Society 22 (SRS-22) and Oswestry Disability Index (ODI) for function. ANOVA technique categorically compared outcome scores to most distal levels of fusion. Linear regression compared patient reported outcomes to time elapsed since surgery. Statistical significance was p < 0.05.

Results

One hundred twelve patients were identified, 50 patients were contacted, and 22 agreed to participation and completed a full assessment. Follow-up time since surgery ranged from 15 to 26 years and age ranged from 30 to 43 years. Six patients reported daily VAS back pain of ≥5; with a mean of 2.5. Back pain was not associated with level of distal fusion (p = 0.92). ODI was 15.36, with six patients' ODI >20. No relationship was shown between ODI and distal level of fusion (p = 0.72). SF-36 and SRS 22 values were also not related to distal level of instrumentation. Patient reported VAS back pain scores (r² = 0.18, p = 0.05), ODI (r² = 0.09, p = 0.17), and SF-36 and SRS-22 were not worse in patients with longer follow-up over time. Back pain and certain functional score subcategories of the SF-36 and SRS-22 trended toward improved results over time.

Conclusions

Most patients who underwent multi-segment spinal fixation appeared to do well long-term, with minimal back pain. Lowest instrumented segment did not appear to be associated with increased back pain after 15 to 25 years follow-up.

Lack of association between DSCAM gene polymorphisms and adolescent idiopathic scoliosis susceptibility in a Chinese Han population

BACKGROUND

In a recent genome wide association study, polymorphisms in the DSCAM and CNTNAP2 genes were reported to be related with susceptibility of AIS. Consequently, further replication studies are warranted in other populations due to ethnic difference in genetic background.

OBJECTIVE

To explore whether single nucleotide polymorphisms (SNPs) of DSCAM (rs2222973) and CNTNAP2 (rs11770843) genes are associated with the susceptibility and curve severity of AIS in a Chinese Han population.

METHODS

A total of 648 AIS patients and 573 age- and sex-matched healthy adolescents in rs2222973 were recruited, and in rs11770843 there were 100 AIS patients and 100 age- and sex-matched healthy adolescents included in present study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was repeatedly carried out to verify the linkage of AIS with SNPs rs2222973 in the DSCAM gene and rs11770843 in the CNTNAP2 gene. Case-control and case-only studies were respectively performed to define the contribution of the DSCAM gene polymorphisms to predisposition and disease severity of AIS.

RESULTS

Association analysis of the DSCAM SNP rs2222973 with AIS revealed no significant differences both in genotype frequency (p= 0.280) and allelic frequency (p= 0.643). The CNTNAP2 SNP rs11770843 (C/T) was not found in either the AIS or control group; all 100 AIS patients and 100 normal controls had the T/T genotype. Among skeletally matured AIS patients, the average maximal Cobb angles were also comparable within different DSCAM genotypes.

CONCLUSION

Our study did not repeatedly confirm the association of the rs2222973 or the rs11770843 with AIS in a Chinese Han population. We concluded that the associations of rs2222973 with AIS predisposition and curve severity are negative in a Chinese Han population.

Letter to the Editor concerning "Accurate prediction of height loss in adolescent idiopathic scoliosis: Cobb angle alone is insufficient" by Shi B, Mao S, Xu L, Sun X, Liu Z, Cheng JCY, Zhu Z and Qiu Y (2016) Eur Spine J; In Press; DOI 10.1007/s00586-016-4530-4

To correct an equation used to estimate height loss in adolescent idiopathic scoliosis in a recent European Spine Journal paper.

Associations of LBX1 gene and adolescent idiopathic scoliosis susceptibility: a meta-analysis based on 34,626 subjects

Background

The results of studies investigating the association between the ladybird homeobox 1 (LBX1) gene polymorphisms and the risk of adolescent idiopathic scoliosis (AIS) are not all the same. As such, we performed a meta-analysis to estimate the association between LBX1 gene polymorphisms and AIS susceptibility.

Methods

Relevant studies published before 15 November 2015 were identified by searching PubMed, EMBASE, ISI web of knowledge, EBSCO, CNKI and CBM. The strength of relationship was assessed by using odds ratios (ORs) and 95 % confidence interval (CI).

Results

A total number of eight case-control studies including 10,088 cases and 24,538 controls were identified. The results showed that T allele of rs111090870 increased AIS susceptibility in Asians (T vs. C, OR = 1.22, 95 % CI: 1.16–1.29, P < 0.001), Caucasians (T vs. C, OR = 1.17, 95 % CI: 1.14–1.21, P < 0.001) and in female (T vs. C, OR = 1.21, 95 % CI: 1.17–1.25, P < 0.001). The G allele of rs678741 decreased AIS risk in female (G vs. A, OR = 0.83, 95 % CI: 0.81–0.85, P < 0.001), and the G allele of the rs625039 increased AIS susceptibility in Asians (G vs. A, OR = 1.14, 95 % CI: 1.11–1.17, P < 0.001).

Conclusions

Our meta-analysis provides evidence that rs111090870, rs678741 and rs625039 polymorphisms near LBX1 gene are associated with AIS susceptibility in some populations. However, our findings are based on only a limited number of studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1139-z) contains supplementary material, which is available to authorized users.

Anterior versus posterior approach in Lenke 5C adolescent idiopathic scoliosis: a meta-analysis of fusion segments and radiological outcomes

Background

Radiological outcomes between anterior and posterior approach in Lenke 5C curves were still controversial. Meta-analysis on published articles to compare fusion segments and radiological outcomes between the two surgical approaches was performed.

Methods

Electronic database was conducted for searching studies concerning the anterior versus posterior approach in Lenke 5C curves. After quality assessment, data of means, standard deviations, and sample sizes were extracted. RevMan 5.3 was adopted for data analysis.

Results

Seven case-control studies involving 308 Lenke 5C AIS patients were identified in the meta-analysis. No significant differences were noted in correction rate of thoracolumbar/lumbar curve (95 % CI −6.02 to 4.32, P = 0.75) and incidence of proximal junctional kyphosis (95 % CI 0.12 to 7.19, P = 0.94) of final follow-up, in change values of thoracolumbar/lumbar curve (95 % CI −3.28 to 7.19, P = 0.46) and thoracic kyphosis (95 % CI −4.10 to 0.13, P = 0.07). The anterior approach represented a significant shorter fusion segments compared to posterior approach (95 % CI −1.72 to −0.71, P < 0.00001). The posterior approach obtained a larger increasing Cobb angle of lumbar lordosis than the anterior approach (95 % CI −6.06 to −0.61, P = 0.02).

Conclusions

The anterior and posterior approach can obtain comparable coronal correction, change values of thoracic kyphosis, and incidence of proximal junctional kyphosis. The anterior approach saves approximate one more fusion segment, and the posterior approach can obtain a larger increasing Cobb angle of lumbar lordosis, from preoperation to final follow-up.

Trial registration

The article type of this study is meta-analysis and prospective registration is not required.

Gelatine matrix with human thrombin decreases blood loss in adolescents undergoing posterior spinal fusion for idiopathic scoliosis: a multicentre, randomised clinical trial

AIMS

In a multicentre, randomised study of adolescents undergoing posterior spinal fusion for idiopathic scoliosis, we investigated the effect of adding gelatine matrix with human thrombin to the standard surgical methods of controlling blood loss.

PATIENTS AND METHODS

Patients in the intervention group (n = 30) were randomised to receive a minimum of two and a maximum of four units of gelatine matrix with thrombin in addition to conventional surgical methods of achieving haemostasis. Only conventional surgical methods were used in the control group (n = 30). We measured the intra-operative and total blood loss (intra-operative blood loss plus post-operative drain output).

RESULTS

Each additional hour of operating time increased the intra-operative blood loss by 356.9 ml (p < 0.001) and the total blood loss by 430.5 ml (p < 0.001). Multiple linear regression analysis showed that the intervention significantly decreased the intra-operative (-171 ml, p = 0.025) and total blood loss (-177 ml, p = 0.027). The decrease in haemoglobin concentration from the day before the operation to the second post-operative day was significantly smaller in the intervention group (-6 g/l, p = 0.013) than in the control group.

CONCLUSION

The addition of gelatine matrix with human thrombin to conventional methods of achieving haemostasis reduces both the intra-operative blood loss and the decrease in haemoglobin concentration post-operatively in adolescents undergoing posterior spinal fusion for idiopathic scoliosis.

TAKE HOME MESSAGE

A randomised clinical trial showed that gelatine matrix with human thrombin decreases intra-operative blood loss by 30% when added to traditional surgical haemostatic methods in adolescents undergoing posterior spinal fusion for idiopathic scoliosis.

Reoperation Rates After Long Posterior Spinal Fusion: Use of Recombinant Bone Morphogenetic Protein in Idiopathic and Non-idiopathic Scoliosis

INTRODUCTION

Bone morphogenetic protein (BMP) can increase the likelihood of solid arthrodesis in spinal surgery. This would imply fewer reoperations for pseudarthrosis, but small cohort sizes are inadequate to monitor these events. We sought to examine adolescent idiopathic (AIS) and non-idiopathic scoliosis (NIS) for reoperation events with and without the use of BMP using a large statewide database.

METHODS

The 2008-2011 New York State Inpatient Database was queried using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Patients age 10 and older with a diagnosis of scoliosis and an index fusion of greater than 2 spinal motion segments were included. Patient identifiers and linkage variables were used to identify revisits. The relative risk of reoperation was calculated. The use of BMP at the initial inpatient stay was used to define the two cohorts for relative risk assessment.

RESULTS

A total of 2,658 and 2,431 cases were identified of AIS and NIS, respectively. The use of BMP at the initial visit was performed at a rate of 4.5% for AIS and 21.0% for NIS fusion surgery. For posterior fusion cases longer than eight levels, the reoperation rate for pseudarthrosis was 1.0% in AIS and 18.4% in NIS (p < .001). For NIS fusions greater than eight levels, the rate of reoperation for pseudarthrosis after using BMP at the index surgery was 5% and 22% when BMP was not used, a relative risk of 4.0 (p < .001). For AIS, there was no substantial increase in risk when not using BMP for fusion greater than eight levels (p < .001).

CONCLUSION

We found a significant decrease in the risk of reoperation for pseudarthrosis after long fusions when using BMP in the case of NIS. In contrast, use of BMP does not benefit the AIS population.

A comparison of four techniques to measure anterior and posterior vertebral body heights and sagittal plane wedge angles in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity of unknown aetiology. Increased growth of the anterior part of the vertebrae known as anterior overgrowth has been proposed as a potential driver for AIS initiation and progression. To date, there has been no objective evaluation of the 3D measurement techniques used to identify this phenomenon and the majority of previous studies use 2D planar assessments which contain inherent projection errors due to the vertebral rotation which is part of the AIS deformity. In this study, vertebral body (VB) heights and wedge angles were measured in a test group of AIS patients and healthy controls using four different image analysis and measurement techniques. Significant differences were seen between the techniques in terms of VB heights and VB wedge angles. The low variability, and the fact that the rotation and tilt of the deformed VBs are taken into account, suggests that the proposed technique using the full 3D orientation of the vertebrae is the most reliable method to measure anterior and posterior VB heights and sagittal plane wedge angles in 3D image data sets. These results have relevance for future investigations that aim to quantify anterior overgrowth in AIS patients for comparison with healthy controls.

Sagittal spino-pelvic adjustment in severe Lenke 1 hypokyphotic adolescent idiopathic scoliosis patients

PURPOSE

The human standing position requires permanent reciprocal spino-pelvic adjustments to obtain a dynamic and economic posture. This study focuses on a hypokyphotic Lenke 1 adolescent idiopathic scoliosis (AIS) patients cohort and points out their particular lumbo-pelvic adaptive mechanisms to maintain a neutral sagittal balance.

METHODS

Preoperative retrospective analysis of prospectively collected data on a monocentric cohort of 455 AIS patients planned for corrective surgery. Radiological low-dose system coupled with a validated clinical routine software allowed to obtain data from eighty-four hypokyphotic [thoracic kyphosis (TK) <20°] Lenke 1 patients and were separately analyzed. Bilateral Student and one-way ANOVAs were conducted for statistical analysis.

RESULTS

Mean Cobb angle was 46.3° (±7.2), TK was 11° (±7.1), sagittal vertical axis (SVA) was -10.1 mm (±30.9), pelvic incidence (PI) was 55.7° (±12.9). Fifty percents of patients were posteriorly imbalanced. Among them, patients with a low PI used an anteversion of their pelvis [indicated by a high pelvic tilt (PT) angle] but were not able to increase their lumbar lordosis (LL) to minimize the posterior spinal shift.

CONCLUSIONS

Hypokyphotic Lenke 1 AIS patients use lumbo-pelvic compensatory mechanisms to maintain their global balance with a poor effectiveness. Subjects with a low PI have a restricted range of LL adaptation. Attention should be paid during surgical planning not to overcorrect lordosis in the instrumented levels in case of non-selective fusion, that may induce posterior shift of the fusion mass and expose to junctional syndromes and poor functional outcomes in this particular patients.

A comparison of vertebral venous networks in adolescent idiopathic scoliosis patients and healthy controls

PURPOSE

Cadaveric studies have previously documented a typical pattern of venous drainage within vertebral bodies (VBs), comprised primarily of the basivertebral vein. These studies, however, are limited by the number of samples available. MRI is able to provide 3D images of soft tissue structures in the spine, including the basivertebral vein without the use of contrast in both healthy controls and subjects with abnormal anatomy such as adolescent idiopathic scoliosis (AIS). This study aimed to quantify the venous networks within VBs of 15 healthy adolescent controls and 15 AIS patients.

METHODS

Five transverse slices through the VBs were examined simultaneously and the observable vascular network traced. The length of the network on the left and right sides of the VB was calculated, and the spatial patterning assessed level-by-level within each subject.

RESULTS

Significant differences were seen in the left/right distribution of vessels in both the control and AIS subjects, with both groups having greater length on the right side of all of their VBs. No difference was seen between AIS and control subjects in any region. Large individual variations in patterns were seen in both groups; however, the control group showed more consistent spatial patterning of the vascular networks across levels in comparison to the AIS group.

CONCLUSION

The length of the basivertebral vein was seen to have a significant bias to the right hand side of the VB in both healthy and AIS adolescents. The spatial pattern of this vein showed large variations in branching both within and across individuals. No significant differences were seen between AIS and control subjects, suggesting both that this network is preserved in deformed AIS vertebrae, and that the vertebral venous system does not play a role in the etiology of AIS.

Trunk imbalance in adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Trunk imbalance (ie, frontal trunk shift measured with a plumb line from C7 to S1) is part of the clinical evaluation in adolescent idiopathic scoliosis (AIS), but its prevalence and relationship with scoliosis, back pain, and health-related factors are not well documented.

PURPOSES

The principal objectives are to document trunk imbalance prevalence and to explore the association between trunk imbalance and the following factors: Cobb angle, type of scoliosis, back pain, function, mental health, and self-image. The secondary objective is to determine back pain prevalence and the relationship between back pain and each of the following: Cobb angle, function, mental health, and self-image.

STUDY DESIGN/SETTING

This is a cross-sectional study in a scoliosis clinic of a tertiary university hospital center.

PATIENT SAMPLE

The sample includes youth with AIS (N=55).

OUTCOME MEASURES

The outcome measures were trunk imbalance prevalence and magnitude, and back pain prevalence and intensity using the Numeric Pain Rating Scale (NPRS) and the Scoliosis Research Society-22 (SRS-22) pain score, and the function, self-image, and mental health domains of the SRS-22.

METHODS

Trunk imbalance and back pain were assessed in 55 patients with AIS (Cobb angle: 10-60°). Patients completed the SRS-22 questionnaire and the NPRS. Correlations were done between trunk imbalance and scoliosis (Cobb angle, type of scoliosis), back pain (NPRS and SRS-22 pain score), and health-related factors using Pearson correlation coefficients (r) and logistic regression models.

RESULTS

Trunk imbalance prevalence is 85% and back pain prevalence is 73%. We found fair to moderate significant positive correlation between trunk imbalance and Cobb angle (r=0.32-0.66, p<.05) but not with back pain, function, mental health, self-image, or type of scoliosis. Lower self-reported pain significantly correlated with lower Cobb angles (r=0.29, p=.03), higher function (r=0.55, p=.000), higher self-image (r=0.44, p=.001), and better mental health (r=0.48, p=.000). There was a trend for trunk imbalance to be related with lower pain in logistic regression models.

CONCLUSIONS

The high prevalence of trunk imbalance in AIS highlights the importance of screening for this clinical sign in growing adolescents. Further research should be done with regard to the treatment of trunk imbalance and its implication on both Cobb angle and back pain.

Flexibility analysis in adolescent idiopathic scoliosis on side-bending images using the EOS imaging system

INTRODUCTION

Analysis of preoperative flexibility in adolescent idiopathic scoliosis (AIS) is essential to classify the curves, determine their structurality, and select the fusion levels during preoperative planning. Side-bending x-rays are the gold standard for the analysis of preoperative flexibility. The objective of this study was to examine the feasibility and performance of side-bending images taken in the standing position using the EOS imaging system.

MATERIAL AND METHODS

All patients who underwent preoperative assessment between April 2012 and January 2013 for AIS were prospectively included in the study. The work-up included standing AP and lateral EOS x-rays of the spine, standard side-bending x-rays in the supine position, and standing bending x-rays in the EOS booth. The irradiation dose was measured for each of the tests. Two-dimensional reducibility of the Cobb angle was measured on both types of bending x-rays.

RESULTS

The results were based on the 50 patients in the study. No significant difference was demonstrated for reducibility of the Cobb angle between the standing side-bending images with the EOS imaging system and those in the supine position for all types of Lenke deformation. The irradiation dose was five times lower during the EOS bending imaging.

CONCLUSION

The standing side-bending images in the EOS device contributed the same results as the supine images, with five times less irradiation. They should therefore be used in clinical routine.

LEVEL OF EVIDENCE

2.

One-step (standard) versus two-step surgical approach in adolescent idiopathic scoliosis posterior spinal fusion: Which is better?

STUDY DESIGN

A retrospective cohort study with IRB approval.

INTRODUCTION

Significant blood loss remains an important concern in terms of the performance of the posterior spinal fusion in adolescent idiopathic scoliosis. Several strategies have been reported to minimize blood loss during surgery. In order to address the need to minimize blood loss without sacrificing the quality of the fusion, in our hospital, we adopted a two-step surgical approach. This surgical approach consist of the exposure and instrumentation of the lumbar region prior to and followed by an extension of the surgical incision to the thoracic region for its subsequent instrumentation. The main purpose of this study was to compare a two-step surgical approach with the one-step (standard) approach.

METHODS

This study was a review of all the data on consecutive posterior spinal fusion surgeries performed by a specific two-surgeon team during 2004-2013. Demographics, surgical variables, radiographic findings, and outcomes regarding blood loss, morbidity, and the duration of the procedure were evaluated.

RESULTS

Eighty-five patients underwent the standard surgical exposure, and 41 patients underwent the two-step surgical technique. With the exception of BMI, neither group showed any statistically preoperative variable significant differences. None of the postoperative outcome variables were statistically significant between both surgical approaches.

CONCLUSIONS

No differences were detected in terms of using a two-step surgical approach versus the one-step standard surgical approach regarding perioperative blood loss, surgical time, or complications.

LEVEL OF EVIDENCE

Level of evidence III.

Morphometric analysis of iatrogenic breast asymmetry secondary to operative breast shape changes in thoracic adolescent idiopathic scoliosis

PURPOSE

Spontaneous surgical alterations of the distorted surface shape of thoracic cage in adolescent idiopathic scoliosis (AIS) may relocate and remodel the bilateral breast mounds. The purpose of this study was to analyze the influence of scoliosis correction surgery on female breast morphology and to identify the risk factors for iatrogenic breast asymmetry secondary to operative breast shape changes in AIS.

METHODS

Thoracic AIS girls undergoing correction surgery were reviewed. Ten parameters concerning morphometric and CT evaluations of breast profile and symmetry were measured. The degree of asymmetry was determined and comparisons were made for evaluation of operative breast shape changes. The morphologically aggravated breast asymmetry would be considered if the concave and convex difference of either sternal notch-nipple length or sternal notch-nipple tilt angle increased post-operatively. Potential risk factors for iatrogenic breast asymmetry were identified.

RESULTS

Sixty-eight AIS girls were reviewed. The concave breasts showed significantly more linear and less angular changes in morphological parameters post-operatively (p < 0.05). The concave and convex difference was significantly increased in morphological parameters and yet decreased in radiographic parameters. Ratio of aggravated morphological breast asymmetry was 61.2 %, and this patient group trended to have a minor pre-operative breast asymmetry though the difference was not statistically significant (p > 0.05). Moreover, patients with apex located at or above T7 showed greater changes in both morphological and radiographic dimensions as compared with those with apex beneath T7 (p < 0.05).

CONCLUSION

The incidence of aggravated post-operative breast asymmetry is notable. Those with higher thoracic apex level, combined with minor pre-operative breast asymmetry, were at relatively higher risk of iatrogenic breast asymmetry aggravation post-operatively. Moreover, discrepancy existed between the morphometric and radiographic parameters concerning the surgical influence on breast asymmetry.

Characterizing the differences between the 2D and 3D measurements of spine in adolescent idiopathic scoliosis

PURPOSE

Although adolescent idiopathic scoliosis (AIS) is known to impact the 3D orientation of the spine and pelvis, the impact of the vertebral position relative to the X-ray scanner on the agreement between 2D and 3D measurements of a curve has not been evaluated. The purpose of this study was to investigate the agreement between 2D and 3D measurements of the scoliotic curve as a function of the 3D spinal parameters in AIS.

METHODS

Three independent observers measured the thoracic and lumbar Cobb angles, Kyphosis, and lordosis on the posterior-anterior and lateral X-rays of AIS patients. The 3D reconstructions were created from bi-planar X-rays and the 3D spinal parameters were calculated in both radio and patient planes using SterEOS software. The degree of agreement between the 2D and 3D measurements was tested and its relationship with the curve axial rotation was determined.

RESULTS

2D and 3D measurements of the sagittal plane spinal parameters were significantly different (p < 0.05). The differences between the 2D and 3D measurements were related to the apical vertebrae rotation, the orientation of the plane of maximum curvature, pelvic axial rotation, and the curve magnitude. Differences between the radio plane and patient plane measurements were related to the pelvic axial rotation, Cobb angles, and apical vertebrae rotation, p < 0.05.

CONCLUSION

Clinically and statistically significant differences were observed between the 2D and 3D measurements of the scoliotic spine. The differences between the 2D and 3D techniques were significant in sagittal plane and were related to the spinal curve and pelvic rotation in transverse plane.

Does It Make a Difference to Stop Fusion at L3 Versus L4 in Terms of Disc and Facet Joint Degeneration: An MRI Study With Minimum 5 Years Follow-up

OBJECTIVES

To compare the functional outcomes of patients with idiopathic scoliosis who had surgical correction and fusion with all pedicle screw construct down to L3 or L4 and to evaluate whether saving a mobile lumbar motion segment distally would demonstrate any difference in terms of disc degeneration (DD) and facet joint degeneration (FJD) after minimum 5 years follow-up.

SUMMARY OF BACKGROUND DATA

Selection of lowest instrumented vertebra (LIV) is often difficult when lumbar curve was included into the fusion (L3 vs L4). Saving L4 is believed to be beneficial for preserving motion and preventing degeneration of unfused lumbar spine.

METHODS

The L3 group included 21 patients (mean age of 21.4) and L4 group included 16 patients (mean age 22.9). Control group included 30 healthy individuals with no spinal deformities (mean age of 23.8). Follow-up lumbar magnetic resonance images (MRIs) were evaluated for each patient in terms of DD and FJD. Clinical evaluation was done by using the Scoliosis Research Society-22r, Oswestry Disability Index, and Numeric Rating Scale.

RESULTS

Mean follow-up period was 7.4 (5-10) years in the L3 group and 9 (5-17) years in L4 group. Average correction rates for lumbar curve magnitudes were 78% in the L3 group and 79% in the L4 group, with no significant correction loss at the final follow-up. There was no statistical difference for DD in all groups (p > .05). FJD was significantly greater in both L3 and L4 groups compared to the control group (p < .001). Clinical outcome scores were similar among all three groups (p > .05).

CONCLUSION

Spinal balance and corrections remained stable, without showing any decompensation over time. This midterm MRI study demonstrated similar disc and facet degeneration rates for L3 and L4 groups. FJD at the upper two levels adjacent to the LIV was significant for both surgically treated groups. Clinical outcome scores were similar for all groups at minimum 5 years follow-up.

Curve Progression in Adolescent Idiopathic Scoliosis With a Minimum of 2 Years' Follow-up After Completed Brace Weaning With Reference to the SRS Standardized Criteria

STUDY DESIGN

A retrospective study.

OBJECTIVES

To investigate curve evolution after brace weaning in adolescent idiopathic scoliosis (AIS) with reference to the Scoliosis Research Society (SRS) criteria.

SUMMARY OF BACKGROUND DATA

Previous studies mainly focused on curve evolution during bracing in AIS. However, curve progression after brace weaning was not well addressed.

METHODS

Braced AIS girls followed up for at least 2 years after brace weaning were reviewed. All patients had radiographs at initial visit, brace weaning, 6 months, 1 year, and 2 years after brace weaning, and last follow-up. Curve progression after brace weaning was separately defined as increase in Cobb angle >5 degrees and curve magnitude >45 degrees. The predictors for curve progression were identified using the independent t test.

RESULTS

200 AIS girls were reviewed. The average duration of follow-up after brace weaning was 51.4 ± 25.6 months. Compared with brace weaning, at 6 months, 1 year, 2 years and last follow-up after brace weaning, 50 (25.0%), 60 (30.0%), 93 (46.5%), and 87 (43.5%) patients, respectively, had curve progression >5 degrees; 0 (0%), 0 (0%), 2 (1%), and 2 (1%) patients, respectively, had surgery recommended; among those with Cobb angle ≤40 degrees at brace weaning, 7 (4.0%), 11 (6.3%), 16 (9.2%), and 18 (10.3%) patients, respectively, had Cobb angle >45 degrees; the mean progression magnitudes were 2.6 ± 5.8, 3.5 ± 5.8, 5.1 ± 6.5, and 5.4 ± 7.4 degrees, respectively; and the mean progression rates were 0.34 ± 0.83, 0.16 ± 0.56, 0.13 ± 0.39, and 0.006 ± 0.28 degrees/month, respectively. Cobb angle at brace weaning was associated with increase in Cobb angle >5 degrees (p = .033) and curve magnitude >45 degrees (p < .001) after brace weaning.

CONCLUSIONS

Curve progression after brace weaning is observed in 43.5% AIS patients. The highest risk occurs within 6 months after brace weaning whereas Cobb angle remains stable after 2 years' follow-up. High Cobb angle at brace weaning indicates high risk of curve progression after brace weaning.

LEVEL OF EVIDENCE

Level III.