Radiological and clinical outcome of selective thoracic fusion for patients with Lenke 1C and 2C adolescent idiopathic scoliosis with a minimum follow-up of 2 years

3D analysis of the preoperative deformity in AIS can be used to guide surgical treatment decisions for selective thoracic fusion

PURPOSE

To identify 3D measures of scoliosis from preoperative imaging that are associated with optimal radiographic outcomes after selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS).

METHODS

Subjects with primary thoracic curves (Lenke 1-4, B or C modifiers) fused selectively (L1 or above) who had preoperative 3D reconstructions and minimum 2 years of follow-up were included. An optimal outcome at 2 years was defined as having 4 of 5 parameters previously defined in the literature: (1) lumbar curve < 26º, (2) deformity flexibility quotient < 4, (3) C7-CSVL < 2 cm, (4) lumbar prominence < 5º and (5) trunk shift < 1.5 cm. Univariate and CART analyses were performed to identify preoperative variables associated with achieving an optimal outcome 2 years postoperatively.

RESULTS

Ninety-nine (88F, 11 M) patients met inclusion. Mean age was 15 ± 2 years. Fifty-one subjects (52%) had an optimal outcome. Seven preoperative deformity measures representing smaller thoracolumbar/lumbar deformity in the optimal group were found to be significant on univariate analysis. CART analysis identified the following variables associated with optimal outcomes: difference in apical rotation > 30° = 27% optimal outcomes, difference in apical rotation ≤ 30° and coronal vertebral wedging of lumbar apex > 3° = 46% optimal outcomes, and difference in apical rotation ≤ 30° and coronal vertebral wedging of lumbar apex ≤ 3° = 80% optimal outcomes (p < 0.05).

CONCLUSION

Optimal outcomes after STF were associated with a preoperative difference in apical vertebral rotation in the axial plane less than 30° between thoracic and lumbar curves as well as coronal plane vertebral wedging of the lumbar apical vertebra less than 3°.

Coronal decompensation following thoracic vertebral body tethering in idiopathic scoliosis

PURPOSE

Post-operative coronal decompensation (CD) continues to be a challenge in the treatment of adolescent idiopathic scoliosis (AIS). CD following selective spinal fusion has been studied. However, there is currently little information regarding CD following Vertebral Body Tethering (VBT). Thus, the goal of this study is to better understand the incidence and risk factors for CD after VBT.

METHODS

Retrospective review of a prospective multicenter database was used for analysis. Inclusion criteria were patients undergoing thoracic VBT, a minimum 2-year follow-up, LIV was L1 or above, skeletally immature (Risser ≤ 1), and available preoperative and final follow-up AP and lateral upright radiographs. Radiographic parameters including major and minor Cobb angles, curve type, LIV tilt/translation, L4 tilt, and coronal balance were measured. CD was defined as the distance between C7PL and CSVL > 2 cm. Multiple logistic regression model was used to identify significant predictors of CD.

RESULTS

Out of 136 patients undergoing VBT, 94 patients (86 female and 6 male) met the inclusion criteria. The mean age at surgery was 12.1 (9-16) and mean follow-up period was 3.4 years (2-5 years). Major and minor curves, AVR, coronal balance, LIV translation, LIV tilt, L4 tilt were significantly improved after surgery. CD occurred in 11% at final follow-up. Lenke 1A-R (24%) and 1C (26%) had greater incidence of CD compared to 1A-L (4%), 2 (0%), and 3 (0%). LIV selection was not associated with CD. Multivariate logistic regression analysis yielded 1A-R and 1C curves as a predictor of CD with the odds ratio being 17.0.

CONCLUSION

CD occurred in 11% of our thoracic VBT patients. Lenke 1A-R and 1C curve types were predictors for CD in patients treated with VBT. There were no other preoperative predictors associated with CD.

Navigation-Assisted One-Staged Posterior Spinal Fusion Using Pedicle Screw Instrumentation in Adolescent Idiopathic Scoliosis-A Case Series

Background and Objectives: Adolescent idiopathic scoliosis (AIS) is a prevalent three-dimensional spinal disorder, with a multifactorial pathogenesis, including genetics and environmental aspects. Treatment options include non-surgical and surgical treatment. Surgical interventions demonstrate positive outcomes in terms of deformity correction, pain relief, and improvements of the cardiac and pulmonary function. Surgical complications, including excessive blood loss and neurologic deficits, are reported in 2.27-12% of cases. Navigation-assisted techniques, such as the O-arm system, have been a recent focus with enhanced precision. This study aims to evaluate the results and complications of one-stage posterior instrumentation fusion in AIS patients assisted by O-arm navigation. Materials and Methods: This retrospective study assesses 55 patients with AIS (12-28 years) who underwent one-stage posterior instrumentation correction supported by O-arm navigation from June 2016 to August 2023. We examined radiological surgical outcomes (initial correction rate, loss of correction rate, last follow-up correction rate) and complications as major outcomes. The characteristics of the patients, intraoperative blood loss, operation time, number of fusion levels, and screw density were documented. Results: Of 73 patients, 55 met the inclusion criteria. The average age was 16.67 years, with a predominance of females (78.2%). The surgical outcomes demonstrated substantial initial correction (58.88%) and sustained positive radiological impact at the last follow-up (56.56%). Perioperative complications, including major and minor, occurred in 18.18% of the cases. Two patients experienced a major complication. Blood loss (509.46 mL) and operation time (402.13 min) were comparable to the literature ranges. Trend analysis indicated improvements in operation time and blood loss over the study period. Conclusions: O-arm navigation-assisted one-stage posterior instrumentation proves reliable for AIS corrective surgery, achieving significant and sustained positive radiological outcomes, lower correction loss, reduced intraoperative blood loss, and absence of implant-related complications. Despite the challenges, our study demonstrates the efficacy and maturation of this surgical approach.

Health-related Quality of Life (HRQOL) Outcomes of Selective/Nonselective Thoracic Fusion for Lenke 1C Adolescent Idiopathic Scoliosis (AIS) Patients with a Minimum 4-year Follow-up

OBJECTIVE

Both the selective thoracic fusion (STF) and nonselective thoracic fusion (NSTF) are treatments for Lenke 1C adolescent idiopathic scoliosis (AIS). To date, the impacts of the two surgical strategies on patients' long-term quality of life remain unclear. Therefore, the purpose of this study was to explore the long-term effects of STF/NSTF on the quality of life in Lenke 1C AIS patients through a 4-10-year follow-up.

METHODS

From January 2011 to April 2018, according to the inclusion and exclusion criteria, a retrospective single-center study of 75 surgical patients with Lenke 1C curves was performed (n = 75). They all underwent posterior fusion, and patients were divided into the selective thoracic fusion (STF) group (n = 42) and the nonselective thoracic fusion (NSTF) group (n = 33) based on their surgical approach. All participants received the survey of the visual analogue scale (VAS), SRS30, SF12, and Oswestry disability index (ODI) scales. Patients' gender, age, body mass index (BMI), surgical approach (STF/NSTF), surgical segments (UIV and LIV), follow-up time, complications, preoperative, postoperative, and last follow-up Cobb angles, and health-related quality of life (HRQOL) outcomes were collected, and analyzed through the Shapiro-Wilks test, Wilcoxon rank-sum test, t-test, and χ2 test.

RESULTS

The mean follow-up of the entire cohort was 73 ± 5.6 months. The lumbar Cobb angle in the STF group improved from 31.8 ± 6.5° to 11.5 ± 5.1° after the operation and 10.3 ± 6.9° at the last follow-up. The postoperative correction rate of the lumbar curve was 63.8%, which increased to 67.7% at the last follow-up. In the NSTF group, the lumbar Cobb angle improved from 34.3 ± 11.3° to 4.3 ± 3.7° after the operation, and was 5.1 ± 3.1° at the last follow-up. The postoperative correction rate of the lumbar curve was 87.4%, and 85.1% at the last follow-up. At the last follow-up, the STF group had higher overall HRQOL scores than the NSTF group, and there were statistically differences between the different groups (STF/NSTF) in SRS-30-Mental health (p = 0.03), SRS-30-Satisfaction with management (p = 0.02), SRS-30-Pain (p = 0.03), ODI (p = 0.01), SF-12 PCS (p = 0.03), VAS back pain (p = 0.005) and VAS leg pain (p = 0.001). No statistically differences were found in SF12 MCS, SRS-30-Self-image/Appearance and SRS-30 Function/activity.

CONCLUSION

After 4-10 years of follow-up, we found that the STF group achieved satisfactory correction results, and compared with the NSTF group, their overall HRQOL scores were higher, especially in terms of pain and satisfaction, where the STF group shows a significant advantage.

Long-term Radiographic and Clinical Outcomes After Selective Thoracic Fusion for Adolescent Idiopathic Scoliosis With Lenke 1C Curve

BACKGROUND

Despite the promising results with selective thoracic fusion (STF) in patients with adolescent idiopathic scoliosis (AIS) of the Lenke 1C curve, postoperative coronal imbalance and progression of the unfused lumbar curve have been concerns in long-term follow-up. In this study, we aimed to investigate the radiographic and clinical outcomes after STF for AIS with Lenke 1C curve with long-term follow-up.

METHODS

A total of 30 patients with AIS with Lenke 1C curves who underwent STF between 2005 and 2017 were included. Minimum follow-up duration was 5 years. Time-dependent changes in radiographic parameters were investigated preoperatively, immediately postoperatively, and at the last follow-up. In addition, radiographic adverse events such as coronal decompensation (CD), lumbar decompensation (LD), distal adding-on (DA) phenomenon, and trunk shift were evaluated at the last follow-up. The Scoliosis Research Society-22 score was used for clinical outcome evaluation.

RESULTS

The mean age at the time of surgery was 13.8 years. The mean follow-up duration was 6.7 ± 0.8 years. The main thoracic curve significantly improved from 57 degrees to 23 degrees (60% correction), and the thoracolumbar/lumbar curve significantly improved from 47 degrees to 28 degrees (41% correction). Coronal balance was 15 mm after surgery but significantly improved to 10 mm at the last follow-up (P = 0.033). At the final follow-up, 11 patients (37%) sustained at least one of the radiographic adverse events: CD in 5 patients (17%), LD in 3 (10%), DA in 4 (13%), and trunk shift in 3 (10.%). However, there were no cases requiring revision surgery. In addition, there were no significant differences in any items or total Scoliosis Research Society-22 score between the patients with and without radiographic adverse events.

CONCLUSION

STF in Lenke 1C curves showed an acceptable risk of adverse radiographic events such as CD, LD, DA, and trunk shift in long-term follow-up. We suggest that STF without fusion to the thoracolumbar/lumbar curve would be sufficient in treating AIS with Lenke 1C curve.

LEVEL OF EVIDENCE

Level III.

Isolated main thoracic curve fusion in idiopathic scoliosis: optimizing radiographic outcomes using lumbar modifiers to guide correction

PURPOSE

Does differential correction of main thoracic curve (MTC) and instrumented LIV angulation based on lumbar modifiers affect radiographic outcomes, and can preoperative supine AP radiograph be used to guide correction for optimal final radiographic alignment.

METHODS

Retrospective analysis of idiopathic scoliosis patients who underwent selective thoracic fusions (LIV T11-L1) for Lenke 1 and 2 curve patterns, < 18 years of age. 2-year minimum follow-up. Optimal outcome meant LIV + 1 of < 5 degrees disk-wedging and C7-CSVL < 2 cm. 82 patients met inclusion criteria (70% female), mean age 14.1 years.

RESULTS

24 patients were A modifier, 21 B modifier, and 37 C modifier. There were 52 optimal and 30 suboptimal outcomes. LIV was not associated with outcome (p = 0.08). For optimal outcomes, A modifiers' MTC improved 65%, B modifiers 65%, and C modifiers 59%. C modifiers' MTC correction was less than A modifiers (p = 0.03) but equivalent to B modifiers' (p = 0.10). A modifiers' LIV + 1 tilt improved 65%, B modifiers 64%, and C modifiers 56%. C modifiers' instrumented LIV angulation was greater than A modifiers' (p < 0.01) but equivalent to B modifiers' (p = 0.06). Preoperative supine LIV + 1 tilt was 16^o in optimal outcomes and 15° in suboptimal outcomes. Instrumented LIV angulation was 9° for both. The correction between preoperative LIV + 1 tilt and instrumented LIV angulation was not significantly different between groups (p = 0.67).

CONCLUSION

Differential MTC and LIV tilt correction based on lumbar modifier may be a valid goal. Optimizing radiographic outcome by matching instrumented LIV angulation to preoperative supine LIV + 1 tilt could not be proven.

LEVEL OF EVIDENCE

IV.

The Importance of Lumbar Curve Flexibility and Apical Vertebral Rotation for the Prediction of Spontaneous Lumbar Curve Correction in Selective Thoracic Fusion for Lenke Type 1 and 2 C Curves: Retrospective Cohort Study with a Mean Follow-Up of More than 10 years

STUDY DESIGN

Retrospective analysis of a prospectively collected data.

OBJECTIVE

Lumbar flexibility(LF) is generally defined with preoperative side bending films;it is not clear what percentage of LF predicts the spontaneous lumbar curve correction (SLCC) at long term follow up. Aim of this study was to find out cut-off value of preoperative LF,apical vertebra rotation(AVR) and apical vertebral translation(AVT);which may predict more than 50%SLCC.

METHODS

Patients with Lenke 1C&2C curves,treated with posterior STF,with a minimum 10 years follow up were included.The patients who had more than 50% SLCC(Group A) or less than 50% (Group B) were compared in terms of LF,AVR and AVT to understand a cut-off value of those parameters.Statistically, Receiver Operating Characteristic(ROC) test was used.

RESULTS

Fifty five AIS patients (54F, 1M) with mean age 14 (11-17) were included to study.Thoracic curve correction rate was 75%;lumbar curve correction rate was 59% at the latest follow up.Group A included 45(82%) patients at the latest follow up.Three patients (5%) showed coronal decompensation at early postop and 2 of them became compensated at f/up.ROC analyses showed 69% flexibility as the cut-off value for SLCC (P < .01).The difference between groups in terms of preop mean AVRs was significant (P = .029) (Group A = 1.9; Group B = 2.4).

CONCLUSION

In Lenke 1C&2C curves,whenever LF on the preoperative bending x-ray is greater than 70% (P < .01)and AVR is equal or less than grade 2,STF provides satisfactory clinical and radiological SLCC with more than mean 10 years f/up.This flexibility rate and apical vertebral rotation can be helpful in decision making for successful STF.

An Analysis of the Risk Factors for Adding-on Phenomena After Posterior Hemivertebral Resection and Pedicle Screw Fixation for the Treatment of Congenital Scoliosis Caused by Hemivertebral Malformation

Objective

To retrospectively analyze the risk factors for adding-on phenomena (AOP) after posterior hemivertebral resection (PHR) and pedicle screw fixation for the treatment of congenital scoliosis (CS) caused by hemivertebral (HV) malformation.

Methods

Patients with CS who underwent surgery and were followed up for more than five years were included in this study. The d general data, such as gender, age, HV segment, Risser sign, and triangular cartilage, postoperative complications, and imaging data at different periods, including the standard anteroposterior and lateral x-rays of the total spine were collected.

Results

In total, 58 patients were included in this study, of which 10 experienced AOP and 48 did not. The results of the single-factor analysis showed that there were statistically significant differences between the patients with AOP and those without in terms of the HV direction, lowest instrumented vertebra (LIV)–upper instrumented vertebra (UIV) (P < 0.05), and postoperative trunk shift (P < 0.05). The results of the logistic regression analysis showed that the HV direction and the postoperative trunk displacement distance were the main risk factors for postoperative AOP. The area under the receiver operating characteristic curve was 0.842 (P < 0.001). The best cut-off value of the adding-on index as an indicator of the occurrence of AOP after surgery was 0.67. When the adding-on index was >0.67, the incidence of postoperative AOP was 90.0%, and the non-occurrence rate was 22.9%.

Conclusion

PHR and pedicle screw fixation is an effective way to treat HV malformation in CS. The HV direction, LIV–UIV, and postoperative TS are risk factors for AOP in patients with CS treated with PHR and pedicle screw fixation. The adding-on index has a high degree of accuracy for the prediction of the occurrence of AOP after PHR and pedicle screw fixation.

Characteristics analysis of segmental and regional lumbar spontaneous compensation post thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis

Objective

To explore the characteristics of compensation of unfused lumbar region post thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis.

Background

Preserving lumbar mobility in the compensation is significant in controlling pain and maintaining its functions. The spontaneous correction of the distal unfused lumbar curve after STF has been widely reported, but previous study has not concentrated on the characteristics of compensation of unfused lumbar region post thoracic fusion.

Method

A total of 51 Lenke 1 and2 AIS patients were included, whose lowest instrumented vertebrae was L1 from January 2013 to December 2019. For further analysis, demographic data and coronal radiographic films were collected before surgery, at immediate erect postoperatively and final follow-up. The wedge angles of each unfused distal lumbar segments were measured, and the variations in each disc segment were calculated at the immediate postoperative review and final follow-up. Meanwhile, the unfused lumbar curve was divided into upper and lower parts, and we calculated their curve angles and compensations.

Results

The current study enrolled 41 females (80.4%) and 10 males (19.6%). Thirty-six patients were Lenke type 1, while 15 patients were Lenke type 2. The average main thoracic Cobb angle and thoracolumbar/lumbar Cobb angle were 44.1 ± 7.7°and 24.1 ± 9.3°, preoperatively. At the final follow-up, the disc wedge angle variation of L1/2, L2/3, L3/4, L4/5 and L5/S1 was 3.84 ± 5.96°, 3.09 ± 4.54°, 2.30 ± 4.53°, − 0.12 ± 3.89° and − 1.36 ± 2.80°, respectively. The compensation of upper and lower coronal lumbar curves at final follow-up were 9.22 ± 10.39° and − 1.49 ± 5.14°, respectively.

Conclusion

When choosing L1 as the lowest instrumented vertebrae, the distal unfused lumbar segments’ compensation showed a decreasing trend from the proximal end to the distal end. The adjacent L1/2 and L2/3 discs significantly contributed to this compensation.

Long-Term Surgical Results of Skip Pedicle Screw Fixation for Patients with Adolescent Idiopathic Scoliosis: A Minimum-Ten-Year Follow-Up Study

Skip pedicle screw fixation for adolescent idiopathic scoliosis (AIS) requires fewer screws and can reduce the risk of neurovascular injury as compared with segmental pedicle screw fixation. However, the long-term impact of screw number reduction on correction and clinical results is unclear. This study examined the 10-year post-operative outcomes of skip pedicle screw fixation for patients with AIS. We reviewed the outcomes of 30 patients who underwent skip pedicle screw fixation for AIS. Radiological and clinical findings were assessed before and immediately, 2 years, and 10 years after surgery in the remaining 25 patients. The mean Cobb angle of the main curve preoperatively and immediately, 2 years, and 10 years post-operatively was 59.4°, 23.4°, 25.8°, and 25.60°, respectively, and was significantly improved at all post-surgical time points (all p < 0.001). The mean correction rate immediately after surgery was 60.8%, and the correction loss rate at the observation end point was 4.8%. The Cobb angle of the lumbar curve was significantly improved immediately after surgery, and the correction persisted until 10 years post-operatively. Remarkable gains were observed for most Scoliosis Research Society-22 patient questionnaire sub-scores at the final follow-up versus preoperative assessments. In conclusion, good correction of the AIS deformity by skip pedicle screw fixation was well maintained over a long follow-up period of 10 years, with clinically meaningful gains in Society-22 patient questionnaire sub-scores.

Selective Thoracic Fusion for King-Moe Type II/Lenke 1C Curve in Adolescent Idiopathic Scoliosis: A Comprehensive Review of Major Concerns

INTRODUCTION

Controversies still exist in the surgical indications and outcomes of selective thoracic fusion (STF) for a primary thoracic curve with a compensatory large lumbar curve (King-Moe type II/Lenke 1C curve) in adolescent idiopathic scoliosis (AIS). Issues of the greatest concern regarding this curve type include curve criteria that indicate STF to prevent postoperative coronal decompensation and postoperative radiographic outcomes, including curve correction, coronal balance, and thoracolumbar kyphosis, after STF.

METHODS

This review comprehensively documents the issues raised in the literature regarding surgical indications and radiographic outcomes of STF for King-Moe type II/Lenke 1C curve in AIS.

RESULTS

Studies suggest that radiographic curve criteria indicating STF for this curve type include the preoperative dominance of the thoracic curve to the lumbar curve in the Cobb angle and the characteristics of the lumbar curve in magnitude and flexibility. Studies warn the need for a careful clinical evaluation of the thoracic and lumbar rotational prominences. Documented radiographic outcomes of importance include the postoperative behavior of the unfused lumbar curve, coronal or sagittal decompensation after STF, and factors associated with these issues. A comprehensive review of the literature suggests that the use of a segmental pedicle screw construct and better instrumented thoracic curve correction achieve better spontaneous lumbar curve correction. Although the causes of postoperative coronal decompensation remain multifactorial, preoperative coronal decompensation to the left and an inappropriate selection of the lowest instrumented vertebra are consistently reported to be the major causative factors.

CONCLUSIONS

STF has been validated in general for the treatment of King-Moe type II or Lenke 1C curve in AIS; however, controversies remain regarding the surgical indications and outcomes. Long-term impacts of residual lumbar curve, coronal decompensation, and mild thoracolumbar kyphosis on clinical outcomes after STF, along with optimal indications and strategy for STF, should further be assessed.