Flexibility assessment of the unfused thoracic segments above the "potential upper instrumented vertebrae" using the supine side bending radiographs in Lenke 5 and 6 curves for adolescent idiopathic scoliosis patients

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.

Do Preoperative Supine Radiographs Predict Postoperative Residual Lumbar Curvatures in Adolescent Idiopathic Scoliosis? A Retrospective Cohort Study

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

This study compares supine vs bending flexibility radiographs and evaluates their ability to predict residual postoperative lumbar curvature after selective thoracic fusion for Lenke 1 and 2 curves across different lumbar modifiers (A, B, and C) in adolescent idiopathic scoliosis (AIS).

METHODS

This was a retrospective review of AIS Lenke 1 and 2 patients who underwent posterior fusion. All patients had preoperative flexibility radiographs including side-bending and supine posteroanterior (PA) films, in addition to pre- and post-operative standing PA and lateral radiographs. We used SurgiMap 2.0 software for all radiographic measurements. Pearson correlations and linear regression models were developed in SAS.

RESULTS

A total of 86 patients were included mean age 14.9 years and follow-up 72.3 months. Preoperative supine lumbar Cobb angle and preoperative side-bending Cobb angles had similar, positive correlations with postoperative lumbar Cobb angle, r = .55 (P < .001) and r = .54 (P < .001), respectively. Three regression models were built to predict postoperative lumbar Cobb angles from preoperative information: Model S (R2 = .39) uses preoperative supine lumbar curve; Model B (R2 = .44) uses preoperative side-bending lumbar curve; Model SB (R2 = .49) uses both preoperative supine and side-bending lumbar curves. Model S and B performed just as well as Model SB.

CONCLUSION

Either supine or side-bending radiographs alone may be used to estimate mean residual postoperative lumbar curvature after selective posterior thoracic fusion, but little is to be gained by taking both supine and side-bending radiographs.

Postoperative proximal junctional kyphosis correlated with thoracic inlet angle in Lenke 5c adolescent idiopathic scoliosis patients following posterior surgery

Background

Proximal junctional kyphosis is a common complication after posterior fusion in patients with adolescent idiopathic scoliosis and is correlated with postoperative changes of thoracic kyphosis. In lenke 5c patients, higher postoperative LL and spontaneous change of TK may produce an effect on final PJK. However, no studies has been performed to evaluate the correlation of PJK with thoracocervical parameters in patients with AIS.

Methods

Data from 98 patients who underwent posterior fusion for Lenke 5C AIS with 2 years of follow-up were retrospectively reviewed. Patients in the extended fusion group underwent fusion at levels higher than upper-end vertebra + 2 (n = 38), and those in the thoracolumbar/lumbar (TL/L) fusion group underwent fusion at UEV + 2 or lower (n = 60).

Results

During an average follow-up of 38.1 months, 23 of 98 patients developed PJK. The extended fusion group had a higher incidence of PJK than the TL/L fusion group (14/38 vs. 9/60, respectively; P = 0.01) and a significantly greater decrease in thoracic kyphosis than the TL/L group (P < 0.01). Patients with PJK had a significantly larger preoperative thoracic inlet angle (TIA) than those without PJK (P < 0.01). Multivariate analysis showed that a greater preoperative TIA and extended fusion were associated with PJK. The Scoliosis Research Society 22-item questionnaire score did not significantly differ between the PJK and non-PJK groups.

Conclusions

The preoperative TIA could be a predictor of PJK. Among patients with Lenke 5C AIS, those with a TIA of > 71° are more likely to develop PJK. Additionally, extended fusion in patients with Lenke 5C may increase the risk of PJK.

Distal adding-on after surgery in Lenke 5C adolescent idiopathic scoliosis: clinical and radiological outcomes

Background

To evaluate the incidence and risk factors of postoperative distal adding-on in patients with Lenke 5C adolescent idiopathic scoliosis (AIS). More accurate selection criteria for the lower instrumented vertebra (LIV) should be confirmed to prevent distal adding-on.

Methods

Forty-six patients with Lenke 5C AIS who underwent posterior fusion were enrolled in the study. Patients were allocated into adding-on and no adding-on groups. Demographic data, clinical data, and radiographic parameters were recorded and compared.

Results

Postoperative distal adding-on occurred in eight patients (17.4%) during follow-up. Demographic data, clinical data, and baseline radiographic parameters of the two groups were not significantly different. The postoperative thoracolumbar (TL) or lumbar (L) Cobb angle, LIV translation, and LIV + 1 translation were higher in the adding-on group than those in the no adding-on group, while the postoperative coronal imbalance of the adding-on group was lower than that of the no adding-on group. The level difference of last barely touched vertebra (LBTV) and last substantial touched vertebra (LSTV) with LIV were higher in the adding-on group than in the no adding-on group.

Conclusion

Postoperative TL/L curve, postoperative LIV translation, postoperative LIV + 1 translation, and postoperative coronal imbalance were determined as risk factors for postoperative distal adding-on in patients with Lenke 5C AIS. Moreover, LIV selection of LBTV-1 or LSTV-1 may cause a higher risk of postoperative distal adding-on.

Feasibility of Single-Stage Posterior Passive Correction and Fusion Surgery for Congenital Scoliosis in Adolescent Patients Who Have Attained Skeletal Maturity

Study Design

Retrospective study.

Purpose

To report the perioperative and radiological outcomes of single-stage posterior passive correction and fusion (SSPPCF) in adolescent patients who present with congenital scoliosis.

Overview of Literature

The surgical treatment for congenital scoliosis is complex. There is no definitive guide on surgical options for skeletally matured adolescent patients who have congenital scoliosis.

Methods

Patients with congenital scoliosis who underwent SSPPCF using a pedicle screw system were reviewed. We identified the following three surgical indications: (1) hemivertebra or wedge vertebra over the thoracic or thoracolumbar region with structural lumbar curves, (2) hemivertebra or wedge vertebra at the lumbar region with significant pelvic obliquity or sacral slanting, and (3) mixed or complex congenital scoliosis. The demographic, perioperative, and radiographic data of these patients were collected.

Results

Thirty-four patients were reviewed. The mean patient age was 14.6±3.4 years. There were 13 hemivertebrae, three wedged vertebrae, two butterfly vertebrae, three hemivertebrae with butterfly vertebra, eight unsegmented bars, and five multiple complex lesions. The average surgical duration was 219.4±68.8 minutes. The average blood loss was 1,208.4±763.5 mL. Seven patients required allogeneic blood transfusion. The mean hospital stay duration was 6.1±2.5 days. The complication rate was 11.8% (4/34): one patient had severe blood loss, one had rod breakage, and two had distal adding-on. The Cobb angle reduced from 65.9°±17.4° to 36.3°±15.3° (p<0.001) with a correction rate (CR) of 44.8%±17.4%. The regional kyphotic angle decreased from 39.9°±20.5° to 27.5°±13.9° (p=0.001) with a CR of 19.3%±49.6%. Radiographic parameters (radiographic shoulder height, clavicle angle, T1 tilt, cervical axis, pelvic obliquity, coronal balance, and apical vertebral translation) showed significant improvement postoperatively.

Conclusions

SSPPCF was a feasible option for adolescent patients with congenital scoliosis who were skeletally matured.

Effect of Instrumentation Level on Mental Health Subscale of Scoliosis Research Society Outcomes Questionnaire in Adolescent Idiopathic Scoliosis

Introduction

Adolescent idiopathic scoliosis (AIS) surgery aims to obtain a flexible and stable spine, correct axial rotation and halt curve progression by fusing the least number of motion segments. Longer fusions can improve deformity correction, but late decompensation and lumbar degeneration may occur. Even some daily issues can be problematic in some scoliosis patients. Reduction in mobility, segmental mobility adjacent to fusion, degeneration of junctional unfused levels and low-back pain (LBP) results in poor outcomes. It is reported that AIS patients have more mental and psychological problems including depression. Preoperative concerns due to deformity may continue postoperatively as instrumentation fuses motion segments. We wanted to present the relationship between the remaining mobile segments and Scoliosis Research Society-22r (SRS-22r) mental health (MH) scores of AIS patients.

Methods

It is a retrospective study of 110 posterior fusion AIS patients, age between 10 and 18 years, and followed-up for at least two years who filled SRS-22r forms both preoperatively and in postoperative second year (POY2). Patients are grouped according to the lowest instrumented vertebra (LIV) as LIV L5: group 1, LIV L4: group 2, LIV L3 and above: group 3.

Results

A statistically significant difference (SSD) was not found in preoperative and POY2 comparison of truncal shift (TTS), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal balance (SB) in group 1; SB in group 2, and LL in group 3 (p>0.05). SSD was found in all other radiologic measurements of groups and in all patients. No SSD was found in function and MH in group 1, in function and pain in group 2 and in pain in group 3 and all patients (p>0.05). SSD was found in the remaining SRS-22r subscales. There was an SSD between groups 1 and 2 in terms of instrumentation level (p=0.013). SSD was found between groups 1 and 2 in preoperative Cobb angle (p=0.016). SSD was found between groups 2 and 3 in POY2 Cobb angle (p=0.025). SSD was found between groups 2 and 3 in POY2 apical vertebral translation (p=0.01). There was no SSD in other radiological parameters (p>0.05).

SSD was found between groups 1 and 2 (p=0.02) and between groups 1 and 3 (p=0.037) in terms of POY2 MH, but no SSD was found between groups 2 and 3 (p>0,05). There was no SSD in other preoperative or POY2 SRS-22r subscales (p>0.05).

Conclusion

More distal LIV is associated with a reduction of mobility and SRS scores. The self-image scores of groups were not statistically different. However, in group 1, MH was significantly lower. With the improvement of body images, patients start to worry about mobility instead of cosmesis. Higher depression has been reported in AIS patients. In POY2, there was no SSD between groups in terms of pain, function and satisfaction in addition to the self-image score as indicated in the literature.

We especially recommend that L5 LIV patients should receive psychiatric support in order to prevent anxiety, and inform and support them that they are not different in terms of pain, self-image and function scores compared to more proximal LIV patients, and also we recommend encouraging L5 LIV patients that POY2 SRS22-r pain, self-image, satisfaction, subtotal and total scores are improved. As reported in the literature which shows increased suicidal thoughts and depression in scoliosis patients; our findings regarding MH are important and considerable.

Selection of Distal Fusion Level for Lenke 5 Curve: Does the Rotation of the Presumed Lower Instrumented Vertebra Matter?

STUDY DESIGN

A retrospective analysis.

OBJECTIVE

To evaluate whether the rotation of the presumed lower instrumented vertebra (LIV) on baseline convex side-bending (SB) radiographs leads to distal adding-on in Lenke 5C adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA

In Lenke 1A patients, derotation of the presumed LIV on baseline bending films is important owing to the association between LIV rotation and postoperative distal adding-on. However, the relationship between distal adding-on and derotation of the presumed LIV in Lenke 5C patients remains unknown.

METHODS

Eighty-five Lenke 5C patients with a minimum of 2-year follow-up for posterior fusion were enrolled. L3 was selected as the LIV in all patients. Patients were divided into the presumed LIV derotation (DR group) and nonderotation (NDR group) groups according to derotation of the presumed LIV on SB films. Radiographic parameters, including Cobb angle, coronal balance, lower disc angle of LIV, LIV tilt, and LIV translation, were measured pre- and postoperatively.

RESULTS

Distal adding-on occurred in 16 patients (18.8%) at the final follow-up: 2 patients (10%) in the DR group and 14 patients (21.5%) in the NDR group (P = 0.248). Distal adding-on incidence was not greatly reduced with derotation of the presumed LIV on SB films at baseline. In the NDR group, the immediately postoperative lower disc angle of the LIV, LIV tilt, and LIV translation were significantly smaller in patients without than in those with distal adding-on (all P < 0.05). Logistic regression analysis revealed that the immediately postoperative LIV tilt and LIV translation were significant predictors of distal adding-on.

CONCLUSION

Derotation of the presumed LIV on SB films may hint less risk of distal adding-on in Lenke 5C patients. Nevertheless, horizontalization of the LIV and minimizing LIV translation during correction could reduce the risk of distal adding-on despite the presence of LIV rotation at baseline.

LEVEL OF EVIDENCE

4.

Comparison of Extending Fusion to Thoracic Curve Versus Thoracolumbar/Lumbar Fusion in Posterior Fusion of Patients with Lenke 5C: Variation in Upper End Vertebrae Tilt Affected Coronal Balance

BACKGROUND

Extended fusion can be performed in patients with Lenke 5C adolescent idiopathic scoliosis (AIS) with a large and relatively rigid thoracic curve. Progression of the thoracic curve is related to coronal imbalance. We aimed to determine the correlation between the upper instrumented vertebra choice and coronal balance in patients with Lenke 5C AIS.

METHODS

A total of 61 patients with Lenke 5C AIS underwent posterior fusion from 2009 to 2015 in a single institution with ≥2 years of follow-up data available. The extended fusion group (n = 32) and thoracolumbar/lumbar (TL/L) fusion group (n = 29) were compared for the correction rates for the main TL/L and thoracic curves, coronal balance, upper end vertebra (UEV) tilt, and Scoliosis Research Society-22 questionnaire score.

RESULTS

Both groups had excellent correction of the main TL/L curve, and the extended fusion group had a significantly greater correction rate of the thoracic curve than the TL/L fusion group (70.2% vs. 57.3%). The incidence of coronal imbalance was similar in both groups. The spontaneous change in UEV tilt was associated with the change in coronal balance from the first to the final follow-up examination. In the TL/L fusion group, the increase in UEV tilt from the first to final follow-up visit resulted in improved coronal balance at the final follow-up examination. Both groups had similar Scoliosis Research Society-22 questionnaire scores at 2 years postoperatively.

CONCLUSIONS

In patients with Lenke 5C AIS, thoracic curve fusion results in better correction of the thoracic curve but no improvement in coronal balance. With TL/L fusion, a postoperative UEV tilt >5° leads to better coronal balance.

Which Side-Bending X-ray Position is Better to Evaluate the Preoperative Curve Flexibility in Adolescent Idiopathic Scoliosis Patients, Supine or Prone?

Study Design

Prospective cohort study.

Purpose

The present study aimed to evaluate the difference in the preoperative curve flexibility between the supine and prone positions in patients with adolescent idiopathic scoliosis (AIS).

Overview of Literature

In AIS, a side-bending view is necessary to differentiate a structural curve from a nonstructural curve using the Lenke classification system. However, there are no published studies about which position, supine or prone, is more effective when evaluating preoperative curve flexibility using side-bending X-ray images in AIS patients.

Methods

Radiographs were analyzed for 32 AIS patients (26 females, six males) who underwent posterior correction and fusion of their main thoracic (MT) curves. Cobb angles of MT, proximal thoracic (PT), and thoracolumbar/lumbar (TL/L) curves were measured preoperatively using upright, supine (anteroposterior and side-bending), and prone (posteroanterior and side-bending) X-rays.

Results

The average Cobb angles of PT, MT, and TL/L curves on preoperative upright/supine/prone X-rays were 29.1°/26.7°/26.6°, 60.7°/48.5°/48.2°, and 41.0°/32.6°/33.1°, respectively. The average Cobb angles of PT, MT, and TL/L curves on supine/prone sidebending X-rays were 19.2°/20.3°, 36.3°/36.4°, and 13.9°/15.7°, respectively. The flexibility rates of PT, MT, and TL/L curves in supine/prone positions were 35.3%/32.5%, 40.6%/40.2%, and 71.7%/68.2%, respectively. Comparing flexibility rates in the prone position with those in the supine position in each case, the average ratios of PT, MT, and TL/L curves were found to be 1.0, 1.0, and 0.9, respectively. There were no statistically significant differences between supine and prone side-bending X-ray measurements. However, the Lenke classification in six of 32 patients (18.8%) differed between supine and prone positions because the TL/L curve in the supine position was slightly more flexible than in the prone position.

Conclusions

Supine side-bending films may be suitable for the evaluation of preoperative curve flexibility in AIS, especially for lumbar modifier C.