Restoring the ideal Roussouly sagittal alignment in Lenke 5 adolescent idiopathic scoliosis patients: a method for decreasing the risk of proximal junctional kyphosis

PURPOSE

Although the Roussouly classification has been widely used in surgical planning for adult scoliosis patients, little is known about whether it can be used to guide sagittal correction for adolescent idiopathic scoliosis (AIS) patients. The purpose of this study was to explore whether the Roussouly classification could be used to help surgeons restore the ideal sagittal alignment for AIS patients to avoid the development of proximal junctional kyphosis (PJK).

METHODS

In this retrospective cohort study, eighty-seven patients with Lenke 5 AIS who underwent surgery from January 2010 to August 2020 were enrolled and divided into two groups: the PJK group and the non-PJK group. All patients were classified into "current types" and "ideal types" according to two versions of the Roussouly classification, and the mismatch rate was evaluated in terms of the consistency between their current type and ideal type. Student's t test, Mann‒Whitney U test, Pearson's Chi-square test, and others were used to compare the two groups regarding patient demographic characteristics (age, sex, Risser sign, etc.) and radiographic parameters (sagittal vertical axis [SVA]; thoracic kyphosis [TK]; thoracolumbar junctional kyphosis [TLK]; lumbar lordosis [LL]; pelvic incidence [PI]; pelvic tilt [PT]; sacral slope [SS]; upper instrumented vertebra [UIV]; lower instrumented vertebra [LIV]; etc.). Multivariate logistic regression with backwards stepwise selection was performed to identify the risk factors for PJK.

RESULTS

PJK was observed in 16 out of 87 patients (18.4%) until the final follow-up. The incidence of PJK was significantly higher in the patients not matching their ideal type than in those who did after surgery (60.9% vs. 3.1%, p = 0.000). The patients with ideal Type 1 had the highest incidence of PJK, while the lowest incidence was observed in patients with ideal Type 2 (50.0% vs. 5.1%, p = 0.000). The PJK group had greater TK, LL, and PI-LL than the non-PJK group before and after surgery. The postoperative PJA in the PJK group was also larger than that in the non-PJK group. Multivariate logistic regression revealed that postoperative Roussouly type mismatch was significantly associated with the occurrence of PJK (OR = 64.2, CI = 9.6-407.1, p = 0.000).

CONCLUSIONS

The Roussouly classification could serve as a prognostic tool for PJK in Lenke 5 AIS patients. Corrective surgery should restore sagittal alignment with respect to the patient's ideal sagittal profile (according to the Roussouly classification based on the PI) to decrease the incidence of PJK in AIS patients.

Assessing progressive changes in axial plane vertebral deformity in adolescent idiopathic scoliosis using sequential magnetic resonance imaging

PURPOSE

To understand how the axial plane deformity contributes to progression of the three-dimensional spinal deformity of Adolescent Idiopathic Scoliosis (AIS), with a main thoracic curve type, using a series of sequential magnetic resonance images (MRI).

METHODS

Twenty-seven AIS patients (at scan 1: mean 12.4 years (± 1.5), mean Cobb angle 29.1°(± 8.8°)) had 3 MRI scans (T4-L1) performed at intervals of mean 0.7 years (± 0.4). The outer profile of the superior and inferior endplates were traced on a reformatted axial image using ImageJ (NIH). Endplate AVR, and intravertebral rotation (IVR), defined as the difference between superior and inferior endplate AVR, was calculated for each vertebral level.

RESULTS

For all patients and scans, the mean AVR was greatest at the curve apex, with AVR diminishing in a caudal and cephalic direction from the apex. At scan 3 the mean apical AVR was 15.1°(± 4.6°) with a mean change in apical AVR between MRI 1 and 3 of 2.7°(± 2.9°). The increase in standing height between MRI 1 and 3 was mean 7.4 cm (± 4.6). Linear regression showed a positive correlation between apical AVR and Cobb angle (R2 = 0.57, P < 0.001), and a positive correlation between apical AVR and rib hump (R2 = 0.54, p < 0.001). The mean change in IVR was greater 3 vertebral levels cephalic and caudal to the apex (1.4°(± 4.1°) and 1.2°(± 2.0°), respectively), compared to the apex (0.4°(± 3.1°)).

CONCLUSIONS

AVR increased, during curve progression, most markedly at the curve apex. The greatest IVR was observed at the periapical levels, with the apex by contrast having only a modest degree of rotation, suggesting the periapical vertebral levels of the scoliosis deformity may be a significant driver in the progression of AIS.

Association of polymorphism in leptin receptor gene with susceptibility of adolescent idiopathic scoliosis

PURPOSE

Abnormal leptin bioavailability has play key roles in the etiology of adolescent idiopathic scoliosis (AIS). Both leptin and its receptor levels may be modulated by the presence of genetic polymorphisms. This study aimed to evaluate the role of polymorphisms in the leptin (LEP) and its main receptor (LEPR) genes in the AIS susceptibility in girls.

METHODS

A retrospective case-control study was conducted with 189 AIS and 240 controls. LEP rs2167270 and LEPR rs2767485 polymorphisms were genotyped using a TaqMan validated assay. Associations were evaluated by odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

The AIS group showed a predominance of girls under 18 years old (n = 140, 74.1%), 148 (78.3%) had low or normal BMI, 111 (58.7%) had Cobb ≥ 45º and 130 (68.7%) were skeletally mature. Minor allele frequencies of rs2167270 and rs2767485 were 35.7% and 18.3%, for AIS and 35.6% and 25.4% for controls, respectively. LEPR rs2767485 T and TC + TT were associated with higher risk of AIS (OR = 1.53; 95% CI = 1.09-2.13 and OR = 1.84; 95% CI = 1.69-2.01, respectively), since CC genotype was only present in the control group. In addition, the LEP rs2167270 GA + AA was more frequent in low weight group (BMI ≤ 24.9) of girls with AIS. There was no significant association between LEP rs2167270 and AIS susceptibility, and LEPR rs2767485 and BMI.

CONCLUSION

The LEPR rs2767485 was associated with the genetic susceptibility of AIS and LEP rs2167270 with low BMI. These data can contribute to the identification of genetic biomarkers to improve the diagnosis and treatment.

Bilateral vertebral body tethering: identifying key factors associated with successful outcomes

PURPOSE

The treatment of operative double major pediatric spinal deformities (e.g., Lenke 3 or 6) with bilateral vertebral body tethering (VBT) can be significantly more challenging when compared to other deformity patterns (e.g., Lenke 1) or treatment with a posterior spinal fusion. We aimed to identify preoperative and perioperative characteristics that were associated with successful postoperative outcomes in patients treated with both a thoracic and thoracolumbar (e.g., bilateral) tether.

METHODS

We retrospectively assessed radiographic and clinical data from patients enrolled in a large multi-center study who had a minimum postoperative follow-up of two years. Standard radiographic parameters were extracted from standing spine and left hand-wrist radiographs at various timepoints. We classified patients based on their preoperative deformity pattern (Primary Thoracic [TP] vs. Primary Thoracolumbar [TLP]) and assessed: (1) deformity balance, (2) tilt of the transitional vertebra, and (3) postoperative success.

RESULTS

We analyzed data from thirty-six patients (TP: 19 and TLP: 17). We observed no relationship between deformity balance at first erect and postoperative success (p = 0.354). Patients with a horizontal transitional vertebra at first erect were significantly (p = 0.001) more likely to exhibit a successful outcome when compared to those who exhibited a tilted transitional vertebra (83% vs. 62%). Patients who had TLP were also more likely to exhibit a successful outcome when compared to patients who exhibited TP (76% vs. 50%).

CONCLUSION

These data indicate that double major deformities can be successfully treated with VBT, particularly for those who exhibit TLP.

Simplified S1 vertebral bone quality (vbq) score to assess proximal junctional kyphosis after Lenke 5 adolescent idiopathic scoliosis surgery

BACKGROUND

Proximal junctional kyphosis (PJK) is a common complication following corrective surgery for adolescent idiopathic scoliosis (AIS) with a Lenke 5 curve. Previous studies have suggested that PJK may be associated with osteopenia, which is prevalent in AIS patients. MRI-based vertebral bone quality (VBQ) scores have been proposed as a valuable tool to assess preoperative bone quality. However, accurately measuring VBQ scores in Lenke 5 AIS patients with a structural lumbar curve can be challenging. Recently, a simplified S1 VBQ score has been proposed as an alternative method when the traditional VBQ score is not applicable. This study aims to evaluate the predictive value of the simplified S1 VBQ score in predicting the occurrence of PJK after corrective surgery for Lenke 5 AIS.

METHODS

We conducted a retrospective analysis of patient data to assess the predictive utility of the S1 VBQ score for PJK in Lenke 5 AIS patients. Demographic, radiographic, and surgical data were collected, and S1 VBQ scores were calculated based on preoperative T1-weighted MRI images. Univariate analysis, linear regression, and multivariate logistic regression were performed to identify potential risk factors for PJK and to assess the correlation between other variables and the S1 VBQ score. Receiver operating characteristic analysis and area under the curve values were used to evaluate the predictive efficiency of the S1 VBQ score for PJK.

RESULTS

A total of 105 patients (aged 15.50 ± 2.36 years) were included in the analysis, of whom 24 (22.9%) developed PJK. S1 VBQ scores were significantly higher in the PJK group compared to the non-PJK group (2.83 ± 0.44 vs. 2.48 ± 0.30, P < 0.001), and there was a significant positive correlation between the S1 VBQ score and proximal junctional angle (PJA) (r = 0.46, P < 0.0001). Multivariate analysis revealed that the S1 VBQ scores and preoperative thoracic kyphosis (TK) were significant predictors of PJK.

CONCLUSION

This study provided evidence that higher S1 VBQ scores were independently associated with PJK occurrence following corrective surgery for Lenke 5 AIS. Preoperative measurement of the S1 VBQ score on MRI may serve as a valuable tool in planning surgical correction for Lenke 5 AIS.

Greater pelvic obliquity in adolescent idiopathic scoliosis combined with hip dysplasia

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a spinal deformity that affects adolescents and poses a challenging public health problem. Compared to the general population, adolescents with AIS have a higher prevalence of hip dysplasia. However, the mechanisms underlying the impact of hip dysplasia on the coronal balance of the spine remain poorly understood. We hypothesized that the combination of AIS with hip dysplasia would exacerbate coronal imbalance.

METHODS

We retrospectively analyzed the medical records and radiographs of adolescents diagnosed with AIS between 2015 and 2020. Participants were divided into two groups: those with hip dysplasia and those without. We recorded parameters related to the coronal deformity of the spine, sacral and pelvic obliquity, and center edge angle (CEA). We investigated differences in these parameters in those with and without hip dysplasia and analyzed their relationships in those with combined AIS and hip dysplasia.

RESULTS

A total of 103 adolescents were included, 36 with hip dysplasia and 67 without. Those with hip dysplasia had significantly higher sacroiliac discrepancy (SID) compared to those without (t = - 2.438, P = 0.017). In adolescents with hip dysplasia, only iliac obliquity angle (IOA) was significantly correlated with SID (r = - 0.803, P < 0.001), with a linear relationship between them (r2 = 0.645, P < 0.001).

CONCLUSIONS

The incidence of hip dysplasia is higher in the AIS population. In adolescents with combined AIS and hip dysplasia, pelvic obliquity is greater, potentially contributing to the increased prevalence of low back pain.

Usefulness of the spectral shaping dual-source computed tomography imaging technique in posterior corrective fusion for adolescent idiopathic scoliosis

PURPOSE

Since childhood exposure to radiation has been demonstrated to increase cancer risk with increase in radiation dose, reduced radiation exposure during computed tomography (CT) evaluation is desired for adolescent idiopathic scoliosis (AIS). Therefore, this retrospective study aimed to investigate the radiation dose of dual-source CT using a spectral shaping technique and the accuracy of the thoracic pedicle screw (TPS) placement for posterior spinal fusion (PSF) in patients with AIS.

METHODS

Fifty-nine female patients with thoracic AIS who underwent PSF using CT-guided TPSs were included and divided into two groups comprised of 23 patients who underwent dual-source CT (DSCT) with a tin filter (DSCT group) and 36 who underwent conventional multislice CT (MSCT group). We assessed the CT radiation dose using the CT dose index (CTDIvol), effective dose (ED), and accuracy of TPS insertion according to the established Neo's classification.

RESULTS

The DSCT and MSCT groups differed significantly (p < 0.001) in the mean CTDIvol (0.76 vs. 3.31 mGy, respectively) and ED (0.77 vs. 3.47 mSv, respectively). Although the correction rate of the main thoracic curve in the DSCT group was lower (65.7% vs. 71.2%) (p = 0.0126), the TPS accuracy (Grades 0-1) was similar in both groups (381 screws [88.8%] vs. 600 screws [88.4%], respectively) (p = 0.8133). No patient required replacement of malpositioned screws.

CONCLUSION

Spectral shaping DSCT with a tube-based tin filter allowed a 75% radiation dose reduction while achieving TPS insertion accuracy similar to procedures based on conventional CT without spectral shaping.

Does intervertebral disc degeneration in adolescent idiopathic scoliosis correlate with patient-reported pain scores? A review of 968 cases

PURPOSE

Report the rate and severity of degenerative disc disease (DDD) in non-surgical adolescent idiopathic scoliosis (AIS) patients and correlate these findings with patient-reported symptomatology scores. Additionally, to quantify the rate of concurrent pathological radiological findings in this group.

METHODS

This was a retrospective chart review study at a single tertiary centre. AIS patients aged 10-16 who had received a whole spine MRI between September 2007 and January 2019 and who had not received surgical intervention to their spine were included. MRI scan reports were screened to extract those who had evidence of DDD. These were then reviewed by a blinded second reviewer who graded every disc using the Pfirrmann grading system. SRS-22 scores were extracted for patients when available.

RESULTS

In total, 968 participants were included in the study. Of these, 93 (9.6%) had evidence of DDD, which was Pfirrmann grade ≥ 3 in 28 (2.9%). The most commonly affected level was L5/S1 (59.1% of DDD cases). A total of 55 patients (5.7%) had evidence of syringomyelia, 41 (3.4%) had evidence of spondylolisthesis (all L5/S1), 14 (1.4%) had bilateral L5 pars defects, and 5 (0.5%) had facet joint degeneration. Spondylolisthesis and bilateral pars defects were more common in patients with DDD identified on MRI scan (p < 0.001 and p = 0.04, respectively). Function (p = 0.048) and pain (p = 0.046) scores were worse in patients with DDD.

CONCLUSION

We present a baseline for the rate and severity of DDD in the non-operative AIS cohort. This should assist in decision-making and counselling of patients prior to surgery.

LEVEL OF EVIDENCE

III.

A comparison between Boston brace and European braces in the treatment of adolescent idiopathic scoliosis (AIS) patients: a systematic review based on the standardised Scoliosis Research Society (SRS) inclusion criteria for brace treatment

PURPOSE

To compare the Boston brace and European braces using a standardised Scoliosis Research Society (SRS) inclusion criteria for brace treatment as well as consensus recommendations for treatment outcome.

METHODS

This was a systematic review that was carried out using MeSH terminology in our search protocol in PubMed, Cochrane Library, Scopus, Clinicaltrials.gov and Web of Science database between 1976 and 29th of Jan 2023. All studies that were included in this review had applied fully/partially the SRS inclusion criteria for brace wear. Outcome measures were divided into primary and secondary outcome measures.

RESULTS

3830 literatures were found in which 176 literatures were deemed relevant to the study once duplicates were removed and titles and abstracts were screened. Of these literatures, only 15 had fulfilled the eligibility criteria and were included in the study. 8 of the studies were Level IV studies, 5 were Level III studies and 2 studies were Level I studies (1 prospective randomised controlled trial (RCT) and 1 Quasi-RCT). The percentage of patients who avoided surgery for European braces ranged from 88 to 100%, whereas for Boston brace ranged from 70 to 94%. When treatment success was assessed based on the final Cobb angle > 45°, approximately 15% of patients treated with European braces had treatment failure. In contrast, 20-63% of patients treated with Boston brace had curves > 45° at skeletal maturity. The BrAIST study used a cut-off point of 50° to define failure of treatment and the rate of treatment failure was 28%. Curve correction was not achieved in most patients (24-51% of patients) who were treated with the Chêneau brace and its derivatives. However, none of the patients treated with Boston brace achieved curve correction.

CONCLUSION

Boston brace and European braces were effective in the prevention of surgery. In addition, curve stabilisation was achieved in most studies. Limitation in current literature included lack of studies providing high level of evidence and lack of standardisation in terms of compliance to brace as well as multidisciplinary management of brace wear.

The effect of Pilates-based exercise applied with hybrid telerehabilitation method in children with adolescent idiopathic scoliosis: A randomized clinical trial

This study aimed to investigate the effect of Pilates-based exercise training applied with hybrid telerehabilitation on Cobb angle, respiratory function, respiratory muscle strength, and functional capacity in patients with adolescent idiopathic scoliosis (AIS). This is an evaluator-blinded, randomized, controlled trial. For the study, 32 patients were randomly allocated into two groups: a hybrid telerehabilitation group (training group), provided with modified Pilates-based exercises with synchronous sessions; and a home-based group (control group), doing the same exercises in their home. The Pilates-based exercise program consists of stretching and strengthening exercises combined with postural corrections and breathing exercises modified according to the curve type and localization of the patients, done every day of the week for 12 weeks. Analyses were made based on the comparison between the angle of trunk rotation, Cobb angle, spirometry, maximal inspiratory (MIP) and expiratory pressures (MEP), and incremental shuttle walk tests done at the beginning and end of the study. The training group showed statistically significant improvements in Cobb angle, PEF%, MIP, and MEP values compared with the control group (p < 0.05).

CONCLUSION

 Pilates-based exercises applied with the hybrid telerehabilitation method can improve Cobb angle and respiratory muscle strength in patients with AIS. The hybrid telerehabilitation method can be used as an alternative to home-based programs, especially in locations and times where there may be limited access to supervised training. Also, the nature of the disease that requires long-term follow-up is another factor where hybrid telerehabilitation may be an advantage.

TRIAL REGISTRATION

 ClinicalTrials.gov ID: NCT05761236.

WHAT IS KNOWN

• Exercise training is one of the main approaches to treating scoliosis.

WHAT IS NEW

• Application of exercises via telerehabilitation method may contribute more to the improvement of scoliosis-related parameters than home-based programs. • Telerehabilitation may be a preferable alternative exercise method in scoliosis, considering the advantages of accessibility and long-term follow-up.

[Imaging study on thoracic and lumbar physiological curvature in adolescent idiopathic scoliosis]

OBJECTIVE

To observe the alteration of thoracic and lumbar physiological curvature in adolescent idiopathic scoliosis(AIS) and the difference of physiological curvature between different types of scoliosis.

METHODS

A retrospective analysis was conducted on 305 adolescent patients taken full spine X-ray in our hospital from January 2017 to December 2021. The patients were divided into normal group and scoliosis group. The normal group was composed of 179 patients, 79 males and 100 females, aged 10 to 18 years old with an average of (12.84±2.10) years old, with cobb agle less than 10 degrees. The scoliosis group was composed of 126 patients, 33 males and 93 females, aged 10 to 18 years old with an average of (13.92±2.20) years old. The gender, age, Risser sign, thoracic kyphosis(TK) and lumbar lordosis(LL) in 2 groups were compared, and the TK and LL were also compared between different genders, different degrees of scoliosis and different segments of scoliosis.

RESULTS

The female ratio(P=0.001) and age (P<0.001) in scoliosis group were higher than them in normal group; the ratio of low-grade ossification was higher in normal group than in scoliosis group(P=0.038). TK was significantly smaller in scoliosis group than in normal group(P<0.001), but there was no significant difference in LL between the 2 groups(P=0.147). There were no significant difference in TK and LL between male and female. The TK was significantly bigger in mild AIS patients than in moderate AIS patients(P<0.05), but there was no significant difference in LL between mild and moderate patients(P>0.05). The TK and LL in different segments scoliosis were not found significant difference.

CONCLUSION

The physiological curvature of thoracic and lumbar spine is independent of gender. The thoracic physiological curvature becomes smaller in AIS patients, but lumbar curvature remains unchanged. The thoracic physiological curvature in mild AIS patients is greater than that in moderate AIS patients, but the lumbar curvature is almost unchanged between mild and moderate scoliosis and is similar with that in normal adolescent. The alteration of thoracic and lumbar physiological curvature in AIS patients may be related to relative anterior spinal overgrowth, and the specific detailed mechanism needs to be further studied.

Scoliocorrector Fatma-UI for correction of adolescent idiopathic scoliosis: Development, effectivity, safety and functional outcome

BACKGROUND

Adolescent idiopathic scoliosis remains a major problem due to its high incidence, high risk, and high cost. One of the aims of the management in scoliosis is to correct the deformity. Many techniques are available to correct scoliosis deformity; however, they are all far from ideal to achieve three-dimensional correction in scoliosis.

AIM

To develop a set of tools named Scoliocorrector Fatma-UI (SCFUI) to aid three-dimensional correction and to evaluate the efficacy, safety, and functional outcome.

METHODS

This study consists of two stages. In the first stage, we developed the SCFUI and tested it in finite element and biomechanical tests. The second stage was a single-blinded randomized clinical trial to evaluate the SCFUI compared to direct vertebral rotation (DVR). Forty-four subjects with adolescent idiopathic scoliosis were randomly allocated into the DVR group (n = 23) and SCFUI group (n = 21). Radiological, neurological, and functional outcome was compared between the groups.

RESULTS

Finite element revealed the maximum stress of the SCFUI components to be between 31.2 - 252 MPa. Biomechanical analysis revealed the modulus elasticity of SCFUI was 9561324 ± 633277 MPa. Both groups showed improvement in Cobb angle and sagittal profile, however the rotation angle was lower in the SCFUI group (11.59 ± 7.46 vs 18.23 ± 6.39, P = 0.001). Neurological and functional outcome were comparable in both groups.

CONCLUSION

We concluded that SCFUI developed in this study resulted in similar coronal and sagittal but better rotational correction compared to DVR. The safety and functional outcomes were also similar to DVR.

Elevated preoperative blood pressure and its relationship to intraoperative mean arterial pressure and blood loss in posterior spinal fusion for adolescent idiopathic scoliosis

PURPOSE

The relationship between preoperative blood pressure (BP) and intraoperative mean arterial pressure (MAP) and estimated blood loss (EBL) in pediatric spine surgery is currently unknown. The objectives of this study were to determine if elevated preoperative BP is associated with elevated intraoperative MAP, EBL, and percentage estimated blood volume (EBV) lost, and to determine if intraoperative MAP is associated with percentage of EBV lost during posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS).

METHODS

This is a retrospective cohort analysis of 209 patients undergoing PSF for AIS between 2016 and 2019 by a single surgeon. Data extracted included demographic characteristics, preoperative systolic and diastolic BP, continuous intraoperative MAP measured by arterial line, EBL, radiographic, and surgical characteristics. Time points of interest for MAP included incision and exposure. Elevated BP was defined as > 1 standard deviation above the mean BP of patients included in the study, and elevated MAP was defined as > 65 mmHg.

RESULTS

Elevated preoperative systolic BP was associated with elevated MAP at incision (p = 0.002). Patients with elevated preoperative diastolic BP had significantly higher MAP at exposure and throughout the procedure (p = 0.04). MAP > 65 at incision was associated with a 5% increase in EBV lost (p < 0.001).

CONCLUSIONS

Patients with elevated preoperative BP parameters have increased MAPs at incision, exposure, and throughout surgery. Elevated MAP at incision is associated with an increased percentage of EBV lost in a small number of patients undergoing PSF for AIS.

Moderate scoliosis continues to progress at 30-year follow-up: a call for concern?

PURPOSE

This natural history study reports long-term radiographic and clinical outcomes of patients with diagnosis of AIS with curves between 30° and 50°. Our purpose was to determine if any intervention in the natural history is warranted.

METHODS

This was a longitudinal descriptive study at a single institution. We reviewed patient factors, radiographic parameters, and patient-reported outcomes at 20- and 30-year follow-up.

RESULTS

A total of 31 patients were included. At skeletal maturity (which was the initial point of measurement), the median age was 17 years (range 12-21), the thoracic Cobb angle was 35° ± 5° (maximum-minimum 27°-47°), and the lumbar Cobb angle was 33° ± 7° (maximum-minimum 18°-45°). The median final follow-up was 35 years (median age 52, range 32-61) when the thoracic Cobb angle was 47° ± 12° (maximum-minimum 31°-74°) and the lumbar Cobb angle was 40° ± 17° (maximum-minimum 19°-69°). At final follow-up, 9 (29%) patients had a structural curve > 50°. Ten (32%) patients had a curve from 40° to 49° and 11 (35%) patients had a curve < 40°. The thoracic Cobb angle had progressed from < 40° to > 50° in 5 patients. Thoracolumbar and lumbar Cobb angles progressed from < 40° to greater than > 50° in 1 and 3 patients, respectively. Few patients had functional limitations according to Roland-Morris, Oswestry, and SF36 scores. Pain scores were minimal at final follow-up.

CONCLUSION

All AIS curves between 30° and 50° at skeletal maturity tend to progress. Thoracic curves progress more than lumbar curves during the first 20 years and then progression slows down. The opposite happens with lumbar curves. Therefore, the rate of progression decreases with thoracic curves and increases with lumbar curves. Nevertheless, few patients have functional limitations. Further follow-up is necessary to define the true long-term outcome of moderate curves at maturity.

Range of surgical strategies for individual adolescent idiopathic scoliosis cases: evaluation of a multi-centre survey

PURPOSE

Surgical treatment of adolescent idiopathic scoliosis (AIS) is very complex, involves many critical decisions and modern instrumentation techniques, and offers multiple possibilities. It is known that the surgical strategy may vary strongly between surgeons for AIS cases. The goal of this study was to document, summarize, and analyse the current biomechanical relevant variabilities in the surgical treatments of individual AIS patient cases.

METHODS

Eight experienced scoliosis surgeons from different hospitals were asked to plan surgeries on 12 representative patients with AIS. The surgeons were provided with radiographs during upright standing in the coronal and sagittal plane, as well as lateral bending images to the left and right. The surgeons were asked to specify the Lenke type, their surgical approach, the resection steps, the planned fusion length, and the type of implants. The data were analysed with respect to the inter-rater variability, which was quantified using the Fleiss Kappa method.

RESULTS

In the selection of the surgical approach, the surgeons concurred most with Lenke curve types 2 (κ = 0.88) and 4 (κ = 0.75). The largest differences were shown at Lenke 1 (κ = 0.39) and 5 (κ = 0.32). Anterior approaches were selected in the majority of cases at Lenke types 5, with an average of 50%. The strongest deviation in fusion length was documented at Lenke curve type 6.

CONCLUSION

The survey highlighted differences in the surgical strategy depending on the Lenke curve type, the direction of the surgical approach, and the surgeon. The main discrepancies between the surgeons were found for Lenke 1, 5, and 6 curves, and consistencies for Lenke 2, 3, and 4. The documented discrepancies indicate the remaining open questions in the surgical treatment and understanding of scoliosis biomechanics.

[Translated article] How do I plan adolescent idiopathic scoliosis surgery? Systematization of a preoperative planning method

Preoperative planning is essential in adolescent idiopathic scoliosis (AIS) surgery to determine the fusion levels and to perform the procedure with greater precision and diligence. However, the protocolized performance of such planning is not as widespread among specialists in training. The aim of this article is to describe in detail the preoperative planning method for AIS used in a specialised paediatric and adolescent spine unit of a referral centre, as well as the logistics and the tactics, supported a free semi-automatic digital measurement and planning software. Three representative cases of different vertebral deformities, treated by posterior spinal fusion after preoperative planning according to the method, are shown. This method is highly suitable for the trainee surgeon as it combines the advantages of traditional and modern methods, and is simple, low-cost, accessible, reproducible and with an educational character.

From PHQ-2 to SRS-22: how a depression screening tool relates to SRS scores in patients with adolescent idiopathic scoliosis

PURPOSE

The aim of our study was to determine the relationship between Patient Health Questionnaire (PHQ) scores-a simple, validated depression screening tool-and Scoliosis Research Society (SRS)-22 questionnaire scores in patients with idiopathic scoliosis (IS).

METHODS

IS patients screened for depression with the PHQ-2 who completed the SRS-22 over a 2-year period were reviewed. If PHQ-2 scores were positive (> 3), the more comprehensive PHQ-9 was administered. Median SRS-22 scores between positive and negative PHQ screens were compared. Nonparametric correlation between PHQ and SRS-22 Mental Health (MH) domain was performed. The ability of the MH domain to discriminate between patients with positive versus negative screens and patients with moderate-severe depression risk versus no-mild risk was evaluated with ROC analysis.

RESULTS

521 patients were included. Patients with + PHQ-2 screens had significantly lower total and individual domain SRS scores, especially within the MH domain (4.0 vs. 3.2). For those with moderate-severe depression risk, total and individual domain scores were also significantly lower (MH domain, 4.0 vs. 3.0, p < 0.05). A weak, but significant correlation was observed between the PHQ and MH domain scores (rho = 0.32, p < 0.001). A cut-off of ≥ 3.6 on the MH domain demonstrated sensitivity of 0.75 and specificity of 0.86 for identifying patients at no-mild risk for depression.

CONCLUSION

Recognizing mental health conditions is critical to successful IS treatment as psychosocial conditions can negatively affect treatment outcomes. IS patients scoring < 3.6 on the SRS-22 MH domain should be considered for depression screening due to an increased risk of moderate-severe depression.

Repeat surgical interventions following "definitive" instrumentation and fusion for idiopathic scoliosis: a 30-year update

PURPOSE

Although spinal fusion (SF) is considered "definitive" treatment in juvenile/adolescent idiopathic scoliosis (JIS/AIS), complications requiring reoperation continue to occur. The purpose of this study was to characterize the evolving rates of reoperation following SF in JIS/AIS.

METHODS

Single-center retrospective review of patients who underwent SF for JIS/AIS as their index surgical treatment between 2013 and 2019. Patient data were collected to identify complications requiring reoperation and factors associated with reoperation. Complication rates from 2013 to 2019 were compared to patients from 1988 to 2012 at the same institution.

RESULTS

This study analyzed 934 patients (81.7% female, mean age at surgery 14.5 ± 2.1). Thirty-eight patients (4.1%) required a total of 47 reoperations, a > 50% decrease in overall complication rate from the 2008-2012 population (4.1% vs 9.6%, respectively, p < 0.001). The decrease stemmed mainly from decreases in rates of infection (1.1% vs 4.1%, p < 0.001) and symptomatic implants (0.4% vs 2.1%, p = 0.004). There were, however, non-significant increases in implant failures (0.6% vs 0.2%, p = 0.4367) and pseudoarthrosis (1.0% vs 0.4%, p = 0.5202). Both of these complications were associated with patients with a higher mean weight (implant failure: 70.4 kg ± 21.1 vs 56.1 kg ± 14.9, p = 0.002; pseudoarthrosis: 85.8 kg ± 27.9 vs 55.9 ± 14.5, p = 0.001).

CONCLUSIONS

Reoperation following SF for JIS/AIS has decreased over the past 7 years when compared to 25 years of historical controls. The changing landscape of reoperation demands further research into the risk factors for those reoperations that have become more common.

How do I plan adolescent idiopathic scoliosis surgery? Systematization of a preoperative planning method

Preoperative planning is essential in adolescent idiopathic scoliosis (AIS) surgery to determine the fusion levels and to perform the procedure with greater precision and diligence. However, the protocolized performance of such planning is not as widespread among specialists in training. The aim of this article is to describe in detail the preoperative planning method for AIS used in a specialized pediatric and adolescent spine unit of a referral center, as well as the logistics and the tactics, supported a free semi-automatic digital measurement and planning software. Three representative cases of different vertebral deformities, treated by posterior spinal fusion after preoperative planning according to the method, are shown. This method is highly suitable for the trainee surgeon as it combines the advantages of traditional and modern methods, and is simple, low cost, accessible, reproducible and with an educational character.

Selection of Fusion Levels in Adolescent Idiopathic Scoliosis

PURPOSE OF REVIEW: Posterior spinal fusion (PSF) is the preferred treatment for adolescent idiopathic scoliosis (AIS) patients with surgical range curves. Selection of the proper upper and lower instrumented vertebrae (UIV and LIV) is essential in curve correction and achieving a successful outcome, while preventing short and long-term complications. RECENT FINDINGS: The literature lacks high-level evidence, especially on outcomes of modern surgical techniques. However, evidence seems to show that a great majority of AIS patients have excellent clinical and functional long-term outcomes after PSF. We have reviewed the evidence and provided our level selection recommendations, which should be weighed against the body of evidence on the topic when selecting fusion levels in AIS.

Morphological alterations of lumbar intervertebral discs in patients with adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Etiology of adolescent idiopathic scoliosis (AIS) is still unknown. Prior in vitro research suggests intervertebral disc pathomorphology as a cause for the initiation and progression of the spinal deformity, however, this has not been well characterized in vivo.

PURPOSE

To quantify and compare lumbar disc health and morphology in AIS to controls.

STUDY DESIGN/SETTING

Cross-sectional study.

METHODS

All lumbar discs were imaged using a 3T MRI scanner. T2-weighted and quantitative T2* maps were acquired. Axial slices of each disc were reconstructed, and customized scripts were used to extract outcome measurements: Nucleus pulposus (NP) signal intensity and location, disc signal volume, transition zone slope, and asymmetry index. Pearson's correlation analysis was performed between the NP location and disc wedge angle for AIS patients. ANOVAs were utilized to elucidate differences in disc health and morphology metrics between AIS patients and healthy controls. α=0.05.

RESULTS

There were no significant differences in disc health metrics between controls and scoliotic discs. There was a significant shift in the NP location towards the convex side of the disc in AIS patients compared to healthy controls, with an associated increase of the transition zone slope on the convex side. Additionally, with increasing disc wedge angle, the NP center migrated towards the convex side of the disc.

CONCLUSIONS

The present study elucidates morphological distinctions of intervertebral discs between healthy adolescents and those diagnosed with AIS. Discs in patients diagnosed with AIS are asymmetric, with the NP shifted towards the convex side, which was exacerbated by an increased disc wedge angle.

CLINICAL SIGNIFICANCE

Investigation of the MRI signal distribution (T2w and T2* maps) within the disc suggests an asymmetric pressure gradient shifting the NP laterally towards the convexity. Quantifying the progression of these morphological alterations during maturation and in response to treatment will provide further insight into the mechanisms of curve progression and correction, respectively.

Assessment of idiopathic scoliosis among adolescents and associated factors in Palestine

PURPOSE

This study aimed to investigate adolescent idiopathic scoliosis (AIS) and its related risk factors, including body mass index (BMI), physical activity (PA), gender, time of the first menstrual cycle, transportation, backpack weight and the way of carrying a backpack.

DESIGN AND METHOD

a cross-sectional quantitative design was utilized. A convenient sample of adolescent students in grades seven through ten was included in the study. A self-reported questionnaire with three sections: demographic data; physical data including height, weight and PA; and Adam's forward bend test to determine each student's spine's Cobb angle by measuring the angle of trunk rotation using a scoliometer. The data were analyzed using SPSS version 25, with confidence intervals of 95%.

RESULTS

A total of 820 schoolchildren participated in the study; 53.7% were female and 46.3% were male. Only 22% of these students engaged in vigorous exercise, compared to 36.7% who engaged in low PA; additionally, 10% of the adolescents had a low BMI. After the analysis, it was found that 5.4% of participants had AIS. Low PA (p = 0.001), being underweight (p = 0.038), and time of first menstrual period (p = 0.033) were significantly associated with AIS, while gender, backpack weight, and way of carrying were not statistically related to AIS. Binary logistic regression identified low PA as an independent predictor of AIS (OR = 7.22, 95%CI [1.64, 31.79]).

CONCLUSIONS

The frequency of AIS in Palestine was significant, which highlighted the importance of this issue at a national and global level. There was an association between AIS and BMI, PA, and the time of the first menstrual cycle, which signifies the importance of early detection of the problem to limit its burden later in life.

PRACTICE IMPLICATIONS

Teachers, teenagers, and their parents should be provided with programs that educate and clarify AIS, and a specific protocol should be established for scoliosis screening in schools.

Radiographic and clinical outcomes after definitive spine fusion for skeletally immature patients with idiopathic scoliosis

PURPOSE

To assess the intermediate-term radiographic and clinical outcomes of skeletally immature idiopathic scoliosis (IS) patients that underwent definitive fusion (DF).

METHODS

A retrospective review of patients with IS who were Risser 0 with open tri-radiate cartilages at the time of DF with minimum 5-year follow-up. Outcomes included Scoliosis Research Society (SRS)-30 scores, major Cobb angle, pulmonary function tests (PFTs), and unplanned returns to the operating room (UPROR). Adding-on was defined as progression of the major Cobb angle > 5° or tilt of the lowest instrumented vertebra > 5°.

RESULTS

Thirty-two patients (78% female, mean age 12.2 ± 1.3 years old, mean preoperative major Cobb 64.8° ± 15.9) were included. Of these patients, 20 (62.5%) experienced adding-on and 6 (18.8%) required a revision surgery to correct their progressive spinal deformity. Adding-on was associated with lower 5-year postoperative SRS scores for appearance (3.7 ± 0.7 vs 4.4 ± 0.3, p = 0.0126), mental health (4.2 ± 0.6 vs 4.6 ± 0.3, p = 0.0464), satisfaction with treatment (4.0 ± 0.8 vs 4.7 ± 0.4, p = 0.0140), and total score (4.0 ± 0.4 vs 4.4 ± 0.2, p = 0.0035). The results of the PFTs did not differ between groups. Patients experienced an average of 0.53 UPROR/patient.

CONCLUSION

DF in skeletally immature patients results in a high rate of adding-on, which adversely affects Health-Related Quality of Life. However, reoperation rates, both planned and unplanned, remain lower when compared to patients undergoing growth-friendly treatment.

Long-term changes in bone mineral density following adolescent idiopathic scoliosis surgery: a minimum 34-year follow-up

PURPOSE

To investigate longitudinal changes in bone mineral density (BMD) in middle-aged female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS).

METHODS

The study subjects were 229 female patients who were diagnosed with AIS and underwent spinal fusion between 1968 and 1988. A two-step survey study was conducted on 19 female AIS patients. BMD, Z-scores, T-scores, and the prevalence of osteoporosis and osteopenia were compared between the initial (2014-2016) and second (2022) surveys. Correlations between the annual changes in Z-scores and T-scores with radiographic parameters, body mass index (BMI), and the number of remaining mobile discs were analyzed.

RESULTS

BMD decreased significantly from the initial (0.802 ± 0.120 g/cm2) to the second survey (0.631 ± 0.101 g/cm2; p < 0.001). Z-scores decreased from 0.12 ± 1.09 to - 0.14 ± 1.04, while T-scores decreased significantly from - 0.70 ± 1.07 to - 1.77 ± 1.11 (p < 0.001). The prevalence of osteopenia and osteoporosis increased significantly from 36.8% to 89.5% (p = 0.002), but the increase in osteoporosis alone was not statistically significant (5.3% to 26.3%; p = 0.180). Moderate negative correlations were found between annual changes in Z-scores and both main thoracic (MT) curve (r = - 0.539; p = 0.017) and lumbar curve (r = - 0.410; p = 0.081). The annual change in T-scores showed a moderate negative correlation with the MT curve (r = - 0.411; p = 0.081).

CONCLUSION

Significant reductions in BMD and an increased prevalence of osteopenia and osteoporosis were observed in middle-aged female AIS patients who had undergone spinal fusion. The decline in Z-scores in patients with AIS suggested that there was an accelerated loss of BMD compared with the general population. Larger residual curves could pose an added osteoporosis risk. Further research is needed to understand if the onset of osteoporosis in AIS patients is attributable to the condition itself or the surgical intervention.

Associations between spinal flexibility and bracing outcomes in adolescent idiopathic scoliosis: a literature review

OBJECTIVES

To identify the existing assessment methods used to measure the spinal flexibility of adolescents with idiopathic scoliosis before bracing and to evaluate the predictive effect of spinal flexibility on bracing outcomes.

METHODS

A broad literature search was performed in the PubMed, Web of Science, EMBASE, CINAHL, Scopus, and Cochrane Library databases to obtain relevant information about spinal flexibility and bracing outcomes. All literature was retrieved by October 14, 2023. The inclusion and exclusion criteria were meticulously determined. The quality of each included study and the level of evidence were evaluated by the Quality in Prognosis Studies (QUIPS) method and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system, respectively.

RESULTS

After screening 1863 articles retrieved from databases, a total of 14 studies with 2261 subjects were eligible for the final analysis in this review. Overall, nine methods of flexibility assessment were identified, including supine radiographs, supine lateral bending radiographs, lateral bending radiographs but without clear positions, hanging radiographs, fulcrum bending physical method, and ultrasound imaging in the positions of supine, prone, sitting with side bending and prone with side bending. In addition, five studies demonstrated that flexibility had a strong correlation with in-brace correction, and eleven studies illustrated that spinal flexibility was a predictive factor of the bracing outcomes of initial in-brace Cobb angle, initial in-brace correction rate, curve progression, and curve regression. The results of GRADE demonstrated a moderate-evidence rating for the predictive value of spinal flexibility.

CONCLUSION

Supine radiography was the most prevalent method for measuring spinal flexibility at the pre-brace stage. Spinal flexibility was strongly correlated with the in-brace Cobb angle or correction rate, and moderate evidence supported that spinal flexibility could predict bracing outcomes.

Evaluation of bone mineral density in adolescent idiopathic scoliosis using a three-dimensional finite element model: a retrospective study

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is often accompanied by osteopenia and osteoporosis, which can cause serious complications. The aim of this study was to determine the specific bone mineral density (BMD) of each vertebral body in patients with AIS using biomechanical finite element modeling based on three-dimensional (3D) reconstruction.

METHODS

This retrospective study involved 56 patients with AIS. Computed tomography (CT) and radiography were performed. Spinal vertebrae were segmented from the spinal CT images of patients with AIS to reconstruct 3D vertebral models. The vertebral models were meshed into tetrahedral finite elements to assess the BMD.

RESULTS

The mean main curve Cobb angle was 88.6 ± 36.7°, and the mean kyphosis angle was 36.8 ± 31.5°. The mean BMD of the global spine was 0.83 ± 0.15 g/cm2. The highest BMD was measured on the concave side of the apex (0.98 ± 0.16 g/cm2). Apical vertebral BMD was negatively correlated with age and height (r = - 0.490, p = 0.009 and r =  - 0.478, p = 0.043, respectively). There were no significant differences in BMD values between the concave and convex sides (p > 0.05).

CONCLUSIONS

The 3D finite element modeling of BMD in patients with AIS is a reliable and accurate BMD measurement method. Using this method, the overall BMD of patients with AIS was shown to gradually decrease from the top to the bottom of the spine. Our findings provide valuable insights for surgical planning, choice of screw trajectories, and additional biomechanical analyzes using finite element models in the context of scoliosis.

Weight-bearing cone-beam CT with extensive coverage for volumetric imaging in adolescent idiopathic scoliosis: system implementation and initial validation

The study aimed to introduce a novel imaging method that generates large-coverage, weight-bearing, and 3D images of the whole spine. The proposed system comprises an X-ray tube, a flat panel detector, and a standing platform. The standing platform rotates the imaged subject, allowing for the acquisition of serial fluoroscopic images from different angles which can be used to create 3D images. To increase the longitudinal coverage, we apply a segmental scanning pattern in which the imaged region is scanned in segments and stitched. To address the issue of data inaccuracy between the segments, redundant areas are set at margins of the segmental images, and registration and stitching algorithms are applied. We conducted validation experiments to evaluate radiation dose and image quality. The dose was evaluated using the volume CT dose index (CTDIvol). For image quality evaluation, we measured the low-contrast and spatial resolution. Additionally, we conducted a clinical study consisting of 30 volunteers with adolescent idiopathic scoliosis who were imaged by our method, and the images were subjectively assessed based on image noise, artifacts, anatomical coverage, diagnostic confidence, and overall quality. The CTDIvol was 1.23 mGy, and the low-contrast resolution was 0.6% at 4 mm and the spatial resolution was 8 lp/cm. The clinical images were generally of good quality, with high scores for all factors evaluated. Our method successfully generates large-coverage, weight-bearing, and 3D images of the whole spine with high image quality and low radiation dose. It shows potential for wider clinical applications for various musculoskeletal conditions.

Impact of pleural effusion at an early period after posterior spinal fusion for adolescent idiopathic scoliosis on future pulmonary function and lung volume

Background

Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) has a potential risk for postoperative pleural effusion. Although pleural effusion at an early period after PSF for AIS occurs with a relatively high frequency and occasionally requires some treatments, the impact of postoperative pleural effusion on future pulmonary function or lung volume (LV) has not been clarified to date. The aim of this study was to evaluate the effect of pleural effusion after PSF for AIS on the postoperative pulmonary function and LV.

Methods

A total of 114 consecutive patients who underwent PSF for AIS followed up greater than 2 years at our institute were retrospectively reviewed. We evaluated postoperative pleural effusion by computed tomography (CT) at the 1-week follow-up and divided patients into the pleural effusion (PF) and non-pleural effusion (NP) groups. We investigated spirometry parameters recorded for testing included vital capacity (VC), forced expiratory volume in the first second (FEV1), %VC, and FEV1% and measured the LV using CT images and a workstation at baseline and 2 years after surgery.

Results

A total of 87 (76.3%) patients with postoperative pleural effusion were identified, but all patients were asymptomatic and did not require additional treatment for postoperative pleural effusion. All pulmonary function parameters at the 2-year follow-up exhibited no significant differences between the two groups. Although preoperative left LV (1.21±0.30 L vs. 1.36±0.34 L; p=.022) and total LV (2.68±0.62 L vs. 2.99±0.73 L; p=.031) were significantly lower in the PF group than in the NP group, all postoperative LV parameters were similar between the two groups.

Conclusions

Pleural effusion at an early period after PSF for AIS was a postoperative occurrence without an impact on future pulmonary function and LV.

Effect of short-term spinal orthosis and insoles application on cobb angle, plantar pressure and balance in individuals with adolescent idiopathic scoliosis

BACKGROUND

Spinal orthosis applications are preferred for conservative treatment of adolescent idiopathic scoliosis, and holistic biomechanical approaches are recommended.

METHODS

This was single-blind, prospective, randomized, controlled study. It included 42 patients (29 females/13 males) aged 10-18 years with adolescent idiopathic scoliosis, Cobb angle of 20°-45°, who were deemed suitable for spinal orthosis use. Patients were randomly divided into two groups: control, spinal orthosis group (n = 21), and insoles and spinal orthosis group (n = 21). All participants used spinal orthoses for 3 months. This study evaluated the functional capacities, quality of life, balance, and plantar pressures of the participants. The evaluations were repeated after 1 week, and 3 months following spinal orthosis application.

FINDINGS

Statistically significant difference and positive effect were observed in Cobb angle (p = 0.008; p = 0.878, respectively), right total (p = 0.037; p = 0.193, respectively), left total (p = 0.037; p = 0.193, respectively), left rearfoot (p = 0.002; p = 0.708, respectively), and right forefoot plantar pressure (p = 0.001; p = 0.739, respectively) in participants in insoles and spinal orthosis group compared with those in the control group. Statistically significant differences and positive effects were observed in swing length (p = 0.001; p = 0.053, respectively) and functional capacity (p = 0.005; p = 0.220, respectively), which are parameters related to postural balance. No change was found in quality of life of either group (p > 0.05).

INTERPRETATION

Insoles may have positive impact on functional capacity, balance, and plantar pressure during long-term follow-up in individuals with scoliosis. Therefore, the evaluation of foot plantar pressure in individuals with scoliosis is recommended, and personalized insoles may be a beneficial option.

Lowest Instrumented Vertebra at L3 Versus L4 in Posterior Fusion for Moderate Lenke 5C Type Adolescent Idiopathic Scoliosis: A Case-Match Radiological Study

OBJECTIVE

To compare the radiological outcomes in Lenke 5C type patients whose lowest instrumented vertebra (LIV) was L3 or L4 in a case-match study.

METHODS

We conducted a retrospective case-match study and included 82 patients in the study. Radiological results before surgery, after surgery, and at last follow-up were recorded and analyzed in the L3 and L4 groups.

RESULTS

After matching the age, Risser's sign, sex, and main Cobb, 41 pairs of patients were enrolled in our study. The total fusion segments in the L3 group (median [interquartile range]: 5.0 [6.0-5.0]) were shorter than those in the L4 group (6.0 [6.5-6.0]). The main curve was significantly corrected after surgery in both groups, and was comparable at the last followup between groups. In addition, according to the results of Fisher precision probability test, there was no significant difference of coronal or sagittal imbalance between the 2 groups at the 2-year follow-up.

CONCLUSION

The correction in coronal and sagittal planes in L3 group and L4 group remains similar. On account of more motion segments, L3 could be an ideal choice as LIV in moderate Lenke 5C type AIS. Long-term follow-up is needed to evaluate the effect of larger compensatory lumbar-sacral curve when stopping at L3.

Rotational Assessment of Thoracolumbar/Lumbar Curves According to Lowest Instrumented Vertebra Level

Background

It is not clearly defined in the literature how the lowest instrumented vertebra (LIV) selection effects the rotation of lumbar vertebrae at fused and unfused levels in thoracolumbar/lumbar (TL/L) curves. The aim of this study was to evaluate the rotational profile of structural TL/L curves, corrected with rod derotation manoeuvre, according to LIV level.

Methods

82 consecutive AIS patients with structural TL/L curves who were treated with long segment posterior instrumentation and fusion were retrospectively evaluated. Patients were divided into three groups according to LIV level: lower end vertebra (LEV) group (32 patients), LEV-1 group (23 patients) and LEV + 1 group (27 patients). Cobb angles of structural curves, coronal and sagittal balance were evaluated with direct roentgenograms. Rotation of upper end vertebra, apical vertebra, LIV-1, LIV and LIV + 1 was evaluated with computerised tomography. Clinical outcomes were assessed using SRS-22 questionnaire.

Results

Mean follow-up time was 31 months (range 24-42 months). Preoperative LIV rotation was measured as 16.03°, 16.08° and 12.68° in LEV, LEV-1 and LEV + 1 groups, which changed postoperatively as 13.36°, 16.52° and 9.74° respectively. Postoperative LIV-1, LIV and LIV + 1 rotation values were significantly higher in LEV-1 group compared to LEV + 1 group. None of the patients developed coronal or sagittal imbalance. No significant differences were observed between the groups in terms of SRS-22 scores.

Conclusions

Axial rotation of LIV and vertebrae adjacent to LIV is higher when the fusion is stopped at LEV-1. However, higher rotation does not seem to cause poor radiologic and clinical outcomes in the last follow-up.

Relationship between Fusion Mass Shift and Postoperative Distal Adding-on in Lenke 1 Adolescent Idiopathic Scoliosis after Selective Thoracic Fusion

STUDY DESIGN

This is a retrospective cohort study.

PURPOSE

This study aims to investigate the risk factors for postoperative distal adding-on in Lenke 1 adolescent idiopathic scoliosis (AIS) and validate the relationship between fusion mass shift (FMS) and postoperative distal adding-on.

OVERVIEW OF LITERATURE

Postoperative distal curve adding-on is one of the complications in AIS. FMS has been proposed to prevent postoperative distal adding-on, which requires further validation from different institutions.

METHODS

This study included 60 patients with Lenke 1 AIS who underwent selective thoracic fusion surgery. Coronal spinal alignment parameters were analyzed preoperatively, postoperatively, and at the final follow-up. The postoperative FMS was divided into two groups: the balanced group (FMS ≤20 mm) and the unbalanced group (FMS >20 mm). An independent t-test was used to compare quantitative data between groups, and a chi-square test was used for qualitative data. Furthermore, binary logistic regression and receiver operating characteristics curve analyses were used to identify the risk factors for postoperative distal adding-on in AIS.

RESULTS

At 2-year follow-up, the unbalanced group was more likely to have adding-on (17 of 24 patients) than the balanced group (six of 36 patients; p<0.001). Twenty-three patients with distal adding-on had significantly greater preoperative and postoperative lower instrumented vertebrae (LIV) rotation, FMS, and FMS angle (FMSA) than those without postoperative distal adding-on. Binary logistic regression analysis selected three independent risk factors for adding-on incidence after surgery: FMS (odds ratio [OR], 1.115; 95% confidence interval [CI], 1.049-1.185; p<0.001), FMSA (OR, 1.590; 95% CI, 1.225-2.064; p<0.001), and postoperative LIV rotation (OR, 6.581; 95% CI, 2.280-19.000; p<0.001).

CONCLUSIONS

Achieving a balanced fusion mass intraoperatively is important to avoid postoperative distal adding-on, with FMS of <20 mm and FMS angle of <4.5°. Furthermore, correcting LIV rotation helps to decrease the incidence of postoperative distal addingon.

Etiopathogenesis of adolescent idiopathic scoliosis (AIS): Role of genetic and environmental factors

Adolescent idiopathic scoliosis (AIS) has been known to be related closely to genetic factors. Higher prevalence of AIS among individuals with family history of scoliosis suggesting critical roles of genetic in the pathogenesis of AIS. However, evidence also suggested that environmental factors such as latitude and sun exposure also play a critical role in the pathogenesis of the disease. While genetic factors played an important role in the occurrence of AIS, environmental factors are more likely to affect the progression of the disease. Although the pathogenesis of AIS remains elusive, current knowledge suggests that genetic factors and its interaction with environmental factors are crucial in the development of the disease, explaining differences in clinical characteristics of AIS across the globe. The aim of this review is to summarize the current knowledge of genetic and environmental factors contributing to AIS and their interactions.

3D printed pedicle screw guides reduce the rate of intraoperative screw revision in adolescent idiopathic scoliosis surgery

BACKGROUND CONTEXT

Pedicle screw fixation has become common in the treatment of adolescent idiopathic scoliosis (AIS). Malpositioned pedicle screws have significant complications and identifying surgical techniques to optimize screw placement accuracy is imperative.

PURPOSE

To compare the rate of intraoperative revision, replacement, or removal of pedicle screws placed utilizing 3D printed guides compared with pedicle screws placed utilizing a freehand technique.

STUDY DESIGN/SETTING

Retrospective cohort study/single academic center.

PATIENT SAMPLE

Thirty-two patients aged 10 to 18 with AIS.

OUTCOME MEASURES

Revision rate of pedicle screws and operative time between groups.

METHODS

A retrospective study was performed on patients 10 to 18 years of age who underwent posterior spinal instrumented fusion for AIS from February 2021 to July 2022. The study received an IRB exemption. Patient demographics, intraoperative measures, and outcome variables were recorded. Intraoperatively, all patients underwent a 3-dimensional fluoroscopic "check scan," which included axial, sagittal, and coronal images, to assess for screw accuracy. A secondary outcome of operative time was compared between groups. The p-values <.05 were considered significant.

RESULTS

A total of 32 patients were included in this study. There were 17 cases in the 3D guided and 15 cases in fluoroscopy-guided freehand cohort. There was a total of 254 pedicle screws using 3D guides and 402 screws using freehand technique. Between cohorts, there were no significant differences in a number of levels fused (p=.54) or length of surgery (p=.36). The total revision rate of 3D guided screw placement was 5.5% and that of the freehand technique was 8.5%. The freehand screw placement group had significantly higher revision rates per vertebral level compared with 3D guided (p=.0096). Notably, 3D printed guides had fewer screws that were removed/revised for being too anterior (7.1%) compared with freehand (23.5%). Surgical time was not significantly different between the 3D guided and freehand cohort (p=.35).

CONCLUSIONS

3D printed guides reduce intraoperative revision rate compared with freehand techniques. Total operative time is comparable to freehand technique.

Anterior fusion surgery with overcorrection in the treatment of adolescent idiopathic scoliosis with Lenke 1 AR curve type: how to achieve overcorrection and its effect on postoperative spinal alignment

BACKGROUND

The efficacy of anterior fusion with overcorrection in the instrumented vertebra for Lenke 1 AR type curves has been reported, but how to achieve overcorrection and how overcorrection affects spinal alignment are unclear. The purpose of this study was to identify the factors that cause overcorrection, and to investigate how overcorrection affects postoperative spinal alignment in the surgical treatment of Lenke 1 AR type curves.

METHODS

Patients who had anterior surgery for a Lenke type 1 or 2 and lumbar modifier AR (L4 vertebral tilt to the right) type scoliosis and minimum 2-year follow-up were included. The radiographic data were measured at preoperative, postoperative 1 month, and final follow-up. The UIV-LIV Cobb angle was determined as the Cobb angle between the upper instrumented vertebra (UIV) and the lower instrumented vertebra (LIV), and a negative number for this angle was considered overcorrection. The screw angle was determined to be the sum of the angle formed by the screw axis and the lower and upper endplates in the LIV and UIV, respectively. The change (Δ) in the parameters from postoperative to final follow-up was calculated. The relationships between the UIV-LIV Cobb angle and other radiographic parameters were evaluated by linear regression analyses.

RESULTS

Fourteen patients met the inclusion criteria. Their median age was 15.5 years, and the median follow-up period was 53.6 months. The median UIV-LIV Cobb angle was -1.4° at postoperative 1 month. The median screw angle was 4.7°, and overcorrection was achieved in 11 (79%) cases at postoperative 1 month. The screw angle (r2 = 0.42, p = 0.012) and Δ FDUV-CSVL (the deviation of the first distal uninstrumented vertebra from the central sacral vertical line, r2 = 0.53, p = 0.003) were significantly correlated with the UIV-LIV Cobb angle.

CONCLUSIONS

Screw placement in the UIV and LIV not parallel to the endplate, but angled, was an effective method to facilitate overcorrection in the instrumented vertebrae. The results of the present study suggest that overcorrection could bring spontaneous improvement of coronal balance below the instrumented segment during the postoperative period.

Respiratory variation in the internal jugular vein does not predict fluid responsiveness in the prone position during adolescent idiopathic scoliosis surgery: a prospective cohort study

BACKGROUND

Respiratory variation in the internal jugular vein (IJVV) has not shown promising results in predicting volume responsiveness in ventilated patients with low tidal volume (Vt) in prone position. We aimed to determine whether the baseline respiratory variation in the IJVV value measured by ultrasound might predict fluid responsiveness in patients with adolescent idiopathic scoliosis (AIS) undergoing posterior spinal fusion (PSF) with low Vt.

METHODS

According to the fluid responsiveness results, the included patients were divided into two groups: those who responded to volume expansion, denoted the responder group, and those who did not respond, denoted the non-responder group. The primary outcome was determination of the value of baseline IJVV in predicting fluid responsiveness (≥15% increases in stroke volume index (SVI) after 7 ml·kg-1 colloid administration) in patients with AIS undergoing PSF during low Vt ventilation. Secondary outcomes were estimation of the diagnostic performance of pulse pressure variation (PPV), stroke volume variation (SVV), and the combination of IJVV and PPV in predicting fluid responsiveness in this surgical setting. The ability of each parameter to predict fluid responsiveness was assessed using a receiver operating characteristic curve.

RESULTS

Fifty-six patients were included, 36 (64.29%) of whom were deemed fluid responsive. No significant difference in baseline IJVV was found between responders and non-responders (25.89% vs. 23.66%, p = 0.73), and no correlation was detected between baseline IJVV and the increase in SVI after volume expansion (r = 0.14, p = 0.40). A baseline IJVV greater than 32.00%, SVV greater than 14.30%, PPV greater than 11.00%, and a combination of IJVV and PPV greater than 64.00% had utility in identifying fluid responsiveness, with a sensitivity of 33.33%, 77.78%, 55.56%, and 55.56%, respectively, and a specificity of 80.00%, 50.00%, 65.00%, and 65.00%, respectively. The area under the receiver operating characteristic curve for the baseline values of IJVV, SVV, PPV, and the combination of IJVV and PPV was 0.52 (95% CI, 0.38-0.65, p=0.83), 0.54 (95% CI, 0.40-0.67, p=0.67), 0.58 (95% CI, 0.45-0.71, p=0.31), and 0.57 (95% CI, 0.43-0.71, p=0.37), respectively.

CONCLUSIONS

Ultrasonic-derived IJVV lacked accuracy in predicting fluid responsiveness in patients with AIS undergoing PSF during low Vt ventilation. In addition, the baseline values of PPV, SVV, and the combination of IJVV and PPV did not predict fluid responsiveness in this surgical setting.

TRAIL REGISTRATION

This trial was registered at www.chictr.org (ChiCTR2200064947) on 24/10/2022. All data were collected through chart review.

Vertebral body tethering for idiopathic scoliosis: a systematic review and meta-analysis

PURPOSE

Vertebral body tethering (VBT) is a recent procedure to correct and reduce spinal curves in skeletally immature patients with adolescent idiopathic scoliosis (AIS). The purpose of this systematic review and meta-analysis is to determine the expected curve reduction and potential complications for adolescent patients after VBT.

METHODS

PubMed, Embase, Google Scholar and Cochrane databases were searched until February 2022. Records were screened against pre-defined inclusion and exclusion criteria. Data sources were prospective and retrospective studies. Demographics, mean differences in Cobb angle, surgical details and complication rates were recorded. Meta-analysis was conducted using a random-effects model.

RESULTS

This systematic review includes 19 studies, and the meta-analysis includes 16 of these. VBT displayed a statistically significant reduction in Cobb angle from pre-operative to final (minimum 2 years) measurements. The initial mean Cobb angle was 47.8° (CI 95% 42.9-52.7°) and decreased to 22.2° (CI 95% 19.9-24.5°). The mean difference is - 25.8° (CI 95% - 28.9-22.7) (p < 0.01). The overall complication rate was 23% (CI 95% 14.4-31.6%), the most common complication was tether breakage 21.9% (CI 95% 10.6-33.1%). The spinal fusion rate was 7.2% (CI 95% 2.3-12.1%).

CONCLUSION

VBT results in a significant reduction of AIS at 2 years of follow-up. Overall complication rate was relatively high although the consequences of the complications are unknown. Further research is required to explore the reasons behind the complication rate and determine the optimal timing for the procedure. VBT remains a promising new procedure that is effective at reducing scoliotic curves and preventing spinal fusion in the majority of patients.

LEVEL OF EVIDENCE

Systematic review of Therapeutic Studies with evidence level II-IV.

Does a dedicated "Scoliosis Team" and surgical standardization improve outcomes in adolescent idiopathic scoliosis surgery and is it reproducible?

PURPOSE

The objective of this study was to determine if standardization improves adolescent idiopathic scoliosis (AIS) surgery outcomes and whether it is transferrable between institutions.

METHODS

A retrospective review was conducted of AIS patients operated between 2009 and 2021 at two institutions (IA and IB). Each institution consisted of a non-standardized (NST) and standardized group (ST). In 2015, surgeons changed institutions (IA- > IB). Reproducibility was determined between institutions. Median and interquartile ranges (IQR), Kruskal-Wallis, and χ2 tests were used.

RESULTS

500 consecutive AIS patients were included. Age (p = 0.06), body mass index (p = 0.74), preoperative Cobb angle (p = 0.53), and levels fused (p = 0.94) were similar between institutions. IA-ST and IB-ST had lower blood loss (p < 0.001) and shorter surgical time (p < 0.001). IB-ST had significantly shorter hospital stay (p < 0.001) and transfusion rate (p = 0.007) than IB-NST. Standardized protocols in IB-ST reduced costs by 18.7%, significantly lowering hospital costs from $74,794.05 in IB-NST to $60,778.60 for IB-ST (p < 0.001). Annual analysis of surgical time revealed while implementation of standardized protocols decreased operative time within IA, when surgeons transitioned to IB, and upon standardization, IB operative time values decreased once again, and continued to decrease annually. Additions to standardized protocol in IB temporarily affected the operative time, before stabilizing.

CONCLUSION

Surgeon-led standardized AIS approach and streamlined surgical steps improve outcomes and efficiency, is transferrable between institutions, and adjusts to additional protocol changes.

The three-dimensional coupling mechanism in scoliosis and its consequences for correction

INTRODUCTION

In idiopathic scoliosis, the anterior spinal column has rotated away from the midline and has become longer through unloading and expansion of the intervertebral discs. Theoretically, extension of the spine in the sagittal plane should provide room for this longer anterior spinal column, allowing it to swing back towards the midline in the coronal and axial plane, thus reducing both the Cobb angle and the apical vertebral rotation.

METHODS

In this prospective experimental study, ten patients with primary thoracic adolescent idiopathic scoliosis (AIS) underwent MRI (BoneMRI and cVISTA sequences) in supine as well as in an extended position by placing a broad bolster, supporting both hemi-thoraces, under the scoliotic apex. Differences in T4-T12 kyphosis angle, coronal Cobb angle, vertebral rotation, as well as shape of the intervertebral disc and shape and position of the nucleus pulposus, were analysed and compared between the two positions.

RESULTS

Extension reduced T4-T12 thoracic kyphosis by 10° (p < 0.001), the coronal Cobb angle decreased by 9° (p < 0.001) and vertebral rotation by 4° (p = 0.036). The coronal wedge shape of the disc significantly normalized and the wedged and lateralized nucleus pulposus partially reduced to a more symmetrical position.

CONCLUSION

Simple extension of the scoliotic spine leads to a reduction of the deformity in the coronal and axial plane. The shape of the disc normalizes and the eccentric nucleus pulposus partially moves back to the midline.

Biomechanical analysis of rod contouring in posterior spinal instrumentation and fusion for 3D correction of adolescent idiopathic scoliosis

PURPOSE

To biomechanically evaluate 3D corrective forces and deformity correction attributable to key parameters of rod contouring in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS).

METHODS

Computerised patient-specific biomechanical models of six AIS cases were used to simulate PSF and evaluate the effects of 5.5-mm cobalt-chrome rod contouring angle (concave-convex angles: 30°-15°, 45°-15° and 60°-15°), length (spanning 4 and 7 vertebrae), and apex location (T7, T9). 3D correction and bone-implant forces were computed and analysed.

RESULTS

By increasing the concave rod contour from 30° to 60°, thoracic kyphosis (TK) increased from 18° ± 2° (15°-19°) to 24° ± 2° (22°-26°), apical vertebra rotation (AVR) correction increased from 41% (SD8%) to 66% (SD18%) whilst the main thoracic curve (MT) correction decreased from 68% (SD6%) to 56% (SD8%). With a contouring length of 4 vs. 7 vertebrae, the resulting TK, AVR and MT corrections were 22° ± 1° (19°-26°) vs. 19° ± 10° (15°-22°), 57% (SD18%) vs. 50% (SD26%) and 59% (SD1%) vs. 69% (SD35%), respectively. With the rod contouring apex at T7 (vs. T9), AVR corrections were 69% (SD19%) vs. 44% (SD9%), with no significant difference in TK and MT corrections, and with comparatively 67% of screw pull-out forces. Corrective forces were more evenly shared with fixation on 7 vs. 4 vertebrae.

CONCLUSION

Rod contouring of a greater angulation, over a shorter portion of the rod, and more centred at the apex of the main thoracic curve apex improved AVR correction and allowed greater restoration of TK, but resulted in significantly higher screw pull-out forces and came at the expense of less coronal plane correction.

The machine-vision image guided surgery system reduces fluoroscopy time, ionizing radiation and intraoperative blood loss in posterior spinal fusion for scoliosis

PURPOSE

To determine if the novel 3D Machine-Vision Image Guided Surgery (MvIGS) (FLASH™) system can reduce intraoperative radiation exposure, while improving surgical outcomes when compared to 2D fluoroscopic navigation.

METHODS

Clinical and radiographic records of 128 patients (≤ 18 years of age) who underwent posterior spinal fusion (PSF), utilising either MvIGS or 2D fluoroscopy, for severe idiopathic scoliosis were retrospectively reviewed. Operative time was analysed using the cumulative sum (CUSUM) method to evaluate the learning curve for MvIGS.

RESULTS

Between 2017 and 2021, 64 patients underwent PSF using pedicle screws with 2D fluoroscopy and another 64 with the MvIGS. Age, gender, BMI, and scoliosis aetiology were comparable between the two groups. The CUSUM method estimated that the MvIGS learning curve with respect to operative time was 9 cases. This curve consisted of 2 phases: Phase 1 comprises the first 9 cases and Phase 2 the remaining 55 cases. Compared to 2D fluoroscopy, MvIGS reduced intraoperative fluoroscopy time, radiation exposure, estimated blood loss and length of stay by 53%, 62% 44%, and 21% respectively. Scoliosis curve correction was 4% higher in the MvIGS group, without any increase in operative time.

CONCLUSION

MvIGS for screw insertion in PSF contributed to a significant reduction in intraoperative radiation exposure and fluoroscopy time, as well as blood loss and length of stay. The real-time feedback and ability to visualize the pedicle in 3D with MvIGS enabled greater curve correction without increasing the operative time.

Lower limb joint burden during walking in adolescent idiopathic scoliosis: investigation of mechanical work during walking

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) is the most prevalent spinal deformity in adolescents. However, pathophysiology and long-term complications remain unclear. Characteristics of the mechanical work in AIS gait have not been well-studied.

PURPOSE

This study aimed to elucidate the characteristics of mechanical work in AIS gait.

STUDY DESIGN

Observational comparison study.

PATIENT SAMPLE

Participants were composed of two groups: scoliosis group with 68 participants and a control group with 17 participants.

OUTCOME MEASURES

Spinal deformity and coronal spinal balance in the scoliosis group were assessed with Cobb angle, coronal balance, and apical vertebra translation. Three-dimensional motion analysis during walking was conducted to calculate lower limb joint works and external work on the whole body's center of mass.

METHODS

Lower limb joint work (JW) and external work on the whole body center of mass (CoM) were compared between the 2 groups with an independent t-test. Inter-limb and intra-limb comparisons of mechanical work were conducted with a paired t-test. The relationships between mechanical work and frontal trunk deformity were investigated in the scoliosis group.

RESULTS

Walking speed and external work on whole body CoM did not differ between the two groups. Compared to the control group, the scoliosis group showed significantly larger JW on the convex and concave sides.

CONCLUSION

The scoliosis group showed increased lower limb joint burden and limited trunk function for mechanical work during walking. Investigation of mechanical work during walking provides insight into the biomechanical characteristics of AIS. Therefore, future studies should be conducted to verify mechanical work characteristics which have relevance to the progression of spinal deformity and the development of lower limb complications in AIS.

Concave rod first vs. convex rod first in AIS instrumentation with differential rod contouring: computer modeling and simulations based on ten AIS surgical cases

PURPOSE

To assess biomechanical differences between AIS instrumentations using concave vs. convex rod first.

METHODS

Instrumentations of ten AIS patients were simulated first with major correction maneuvers using the concave rod then with convex rod. Correction maneuvers were concave/convex rod translation, followed by apical vertebral derotation and then convex/concave rod translation. The concave/convex rods were 5.5/5.5 and 6.0/5.5 mm diameter Co-Cr and contoured to 35°/15°, 55°/15°, 75°/15° and 85°/15°, respectively.

RESULTS

Differences in simulated thoracic Cobb angle (MT), thoracic kyphosis (TK) and apical vertebral rotation (AVR) were less than 5° between the two techniques; mean bone-screw force difference was less then 15N (p > 0.1). Increasing differential contouring angle from 35°/15° to 85°/15°, the MT changed from 14 ± 7° to 15 ± 8°, AVR from 12 ± 4° to 6 ± 5°, TK from 23 ± 4° to 42 ± 4°, and bone-screw forces from 159 ± 88N to 329 ± 170N (P < 0.05). Increasing the concave rod diameter from 5.5 to 6 mm, the mean MT correction improvement for both techniques was less than 2°, the AVR correction was improved by 2°, the TK increased by 4° and bone-screw force increased by about 25N (p < 0.05).

CONCLUSION

There was no significant difference in deformity corrections and bone-screw forces between the two techniques. Increasing differential contouring angle and rod diameter improved AVR and TK corrections with no significant effect on the MT Cobb angle. Although this study simplified the complexity of a generic surgical technique, the main effects of a limited number of identical steps were replicated for each case in a systematic manner to analyze the main first-order effects.

Impact of mental health components on the development of back pain in young adults with adolescent idiopathic scoliosis

BACKGROUND

Back pain occurs commonly in adults and is multifactorial in nature. This study aimed to assess the prevalence and intensity of back pain during young adulthood in subjects with adolescent idiopathic scoliosis (AIS), as well as factors that may be associated with its prognosis.

METHODS

Subjects with AIS aged 20-39 treated conservatively were included in this study. Patient-reported outcome measures in adulthood involved episodes of back pain, and scales of self-image, depression, anxiety, and stress. Additionally, pain, self-image, and mental health scores were retrieved at the first clinic consultation. Occurrence of back pain was defined as a numeric pain rating scale ≥ 6.

RESULTS

101 participants were enrolled. The prevalence of back pain in the lifetime, past 12 months, past 6 months, past 1 month, past 7 days, and past 24 h were 37%, 35%, 31%, 27%, 23%, and 20%, respectively. Male, self-image, and depression were significant associated factors for the development of back pain at all time points. Furthermore, the analyses of the initial presentation of participants have shown that participants with back pain in adulthood were characterised by poor self-image and mental health during their adolescence.

CONCLUSION

The present study addressed the natural history of back pain in young adults with conservatively treated AIS. Psychological makeup has been shown to constitute the development of back pain and is strongly hinted as an early sign of having back pain in adulthood among subjects with AIS.

Developing a new tool for scoliosis screening in a tertiary specialistic setting using artificial intelligence: a retrospective study on 10,813 patients: 2023 SOSORT award winner

PURPOSE

The study aims to assess if the angle of trunk rotation (ATR) in combination with other readily measurable clinical parameters allows for effective non-invasive scoliosis screening.

METHODS

We analysed 10,813 patients (4-18 years old) who underwent clinical and radiological evaluation for scoliosis in a tertiary clinic specialised in spinal deformities. We considered as predictors ATR, Prominence (mm), visible asymmetry of the waist, scapulae and shoulders, familiarity, sex, BMI, age, menarche, and localisation of the curve. We implemented a Logistic Regression model to classify the Cobb angle of the major curve according to thresholds of 15, 20, 25, 30, and 40 degrees, by randomly splitting the dataset into 80-20% for training and testing, respectively.

RESULTS

The model showed accuracies of 74, 81, 79, 79, and 84% for 15-, 20-, 25-, 30- and 40-degrees thresholds, respectively. For all the thresholds ATR, Prominence, and visible asymmetry of the waist were the top five most important variables for the prediction. Samples that were wrongly classified as negatives had always statistically significant (p ≪ 0.01) lower values of ATR and Prominence. This confirmed that these two parameters were very important for the correct classification of the Cobb angle. The model showed better performances than using the 5 and 7 degrees ATR thresholds to prescribe a radiological examination.

CONCLUSIONS

Machine-learning-based classification models have the potential to effectively improve the non-invasive screening for AIS. The results of the study constitute the basis for the development of easy-to-use tools enabling physicians to decide whether to prescribe radiographic imaging.

Vertebral bone quality score as a novel predictor of proximal junctional kyphosis after thoracic adolescent idiopathic scoliosis surgery

INTRODUCTION

Proximal junctional kyphosis (PJK) is one of the most common complications after thoracic AIS surgery. Previous studies reported that the etiology of PJK was associated with osteopenia and meanwhile the AIS patients were found osteopenia which could persist into adulthood. Recently, an MRI-based vertebral bone quality score (VBQ) was reported to be a promising tool which can assess preoperative bone quality.

OBJECTIVE

This study aims to evaluate the utility of VBQ score in predicting PJK after corrective surgery for thoracic AIS (Lenke 1 and 2).

METHODS

We conducted a retrospective study to identify the predictive efficiency of VBQ score for PJK in thoracic AIS patients. Demographic, radiographic parameters, and surgical variables were collected. VBQ score was calculated using preoperative T1-weighted MRI. Univariate analysis, linear regression, and multivariate logistic regression were performed to determine potential risk factors of PJK and correlation between other parameters and VBQ score. Receiver operating characteristic analysis and area under the curve values were utilized to evaluate the predictive efficiency of VBQ score for PJK.

RESULTS

A total of 206 patients (aged 14.4 ± 2.3 years) were included, of which 33 (16.0%) developed PJK. VBQ scores were significantly different between the PJK and non-PJK groups (2.8 ± 0.2 vs 2.5 ± 0.2, P < 0.01). A significant positive correlation was found between VBQ score and PJA (R2 = 0.1728, P < 0.01).On multivariate analysis, VBQ score was the only significant predictor of PJK (odds ratio = 2.178, 95% CI = 1.644-2.885, P < 0.001), with a predictive accuracy of 83%.

CONCLUSION

Higher VBQ scores were independently associated with PJK occurrence after corrective surgery for thoracic AIS. Preoperative measurement of VBQ score on MRI may serve as a valuable tool in planning thoracic AIS surgery.

Radiographic and perioperative outcomes following anterior thoracic vertebral body tethering and posterior lumbar spine tethering: a pilot series

BACKGROUND AND CONTEXT

 In patients with adolescent idiopathic scoliosis (AIS) of main thoracic and lumbar spine regions, combined anterior thoracic vertebral body tethering and posterior lumbar spine tethering (ATVBT/PLST) is a novel non-fusion treatment option for growth modulation and conservation of motion.

METHODS

 Fourteen patients with AIS who underwent ATVBT/PLST with at least 2-year follow-up were included. Primary outcomes included quality of life as assessed by SRS-22 instruments, radiographic analysis, and revision operations. We secondarily reported perioperative metrics and post-operative opiate morphine equivalents (OME). Clinical success was defined as patients who achieved skeletal maturity with ≤ 30° curve magnitude of both their main thoracic and thoracolumbar/lumbar curves and who did not undergo posterior spine instrumentation and fusion (PSIF).

RESULTS

Patients had a mean age of 11.6 years (range 10-14 years), majority were girls (92%), and mean follow-up was 3.0 years (range 2-4.8 years). All patients were skeletally immature with a Risser ≤ 2. Included curves were Lenke 1C, 3C, or 6C. Mean preoperative curve magnitudes were 53° ± 8° (range 45°-65°) main thoracic and 49° ± 9° (range 40°-62°) thoracolumbar/lumbar curves. At most recent follow-up, patients had a mean main thoracic curve of 29° ± 8° (range 15°-40°) and a mean thoracolumbar/lumbar curve of 20° ± 15° (range 4°-35°). 50% required a revision operation. Cable breakage occurred in 43%, which did not always require revision. One patient progressed to thoracic fusion, but no patient underwent lumbar fusion. Patients had a mean SRS-22 outcome score of 4.2 ± 0.4.

CONCLUSIONS

ATVBT/PLST is a potential alternative to spine fusion for select immature patients with AIS at a minimum 2-year follow-up. ATVBT/PLST potentially offers motion conservation at the cost of a higher revision rate. Further study and reporting of results are necessary to refine indications and techniques, which in turn will improve outcomes of this procedure.

LEVEL OF EVIDENCE

Level IV-Case series without comparative group.

Adolescent idiopathic scoliosis with concomitant spondylolysis: choice of fusion levels and evaluation of the outcomes obtained leaving the lytic level not instrumented

PURPOSE

7% of adolescent idiopathic scoliosis (AIS) patients also present with a pars defect. To date, there are no available data on the results of fusion ending proximal to a spondylolysis in the setting of AIS. The aim of this study was to analyze the outcomes of posterior spinal fusion (PSF) in this patient cohort, to investigate if maintaining the lytic segment unfused represents a safe option.

METHODS

Retrospective review of all patients who received PSF for AIS, presented with a spondylolysis or spondylolisthesis and had a min. 2-year follow-up. Demographic data, instrumented levels, and preoperative radiographic data were collected. Mechanical complications, coronal or sagittal parameters, amount of slippage, and pain levels were evaluated.

RESULTS

Data from 22 patients were available (age 14.4 ± 2.5 years), 18 Lenke 1-2 and 4 Lenke 3-6. 5 patients (24%) had an isthmic spondylolisthesis, all Meyerding I. The mean preoperative Cobb angle of the instrumented curves was 58 ± 13°. For 18 patients, the lowest instrumented vertebra (LIV) was the last touched vertebra (LTV); for 2, LIV was distal to the LTV; for 2, LIV was one level proximal to the LTV. The number of segments between the LIV and the lytic vertebra ranged from 1 to 6. At the last follow-up, no complications were observed. The residual curve below the instrumentation measured 8.5 ± 6.4°, the lordosis below the instrumented levels was 51.4 ± 13°. The magnitude of the isthmic spondylolisthesis remained constant for all included patients. Three patients reported minimal occasional low back pain.

CONCLUSION

The LTV can be safely used as LIV when performing PSF for the management of AIS in patients with L5 spondylolysis.

Adolescent idiopathic scoliosis is associated with muscle area asymmetries in the lumbar spine

PURPOSE

While the etiopathogenesis of adolescent idiopathic scoliosis (AIS) remains unclear, it is assumed that muscular asymmetries contribute to curve progression. As previous studies have found asymmetries of the thoracic paraspinal muscles in AIS patients, our study's aim was to analyze differences in the erector spinae, multifidus, quadratus lumborum, and psoas muscles of the lumbar spine depending on the curve's radiographic characteristics.

METHODS

We retrospectively included all patients who received posterior reposition spondylodesis for AIS treatment at our institution. Patients were classified according to the Lenke classification. Muscle cross-sectional areas were obtained from magnetic resonance imaging of the lumbar spine. Data were analyzed with the Wilcoxon rank sum test, the Kruskal-Wallis test with post hoc testing, or the Spearman's correlation coefficient.

RESULTS

Seventy-four (14 males and 60 females) AIS patients with a median age of 16 (IQR ± 4) years and a mean Cobb angle of 56.0° (± 18.0°) were included. In curve types Lenke 1 and 2 (n = 45), the erector spinae (p < 0.001) and multifidus (p < 0.001) muscles had a significantly larger cross-sectional area on the convex side, whereas the quadratus lumborum (p = 0.034) and psoas (p < 0.001) muscles each had a significantly larger cross-sectional area on the lumbar contralateral side.

CONCLUSION

Our results show an asymmetry of the lumbar spine's muscles which depends on both the convexity and the extent of the scoliotic curve. While our results cannot prove whether these differences are the deformity's cause or effect, they may contribute to a better understanding of AIS pathogenesis and may allow for more specific preoperative physiotherapy.