Is Anterior Release Obsolete or Does It Play a Role in Contemporary Adolescent Idiopathic Scoliosis Surgery? A Matched Pair Analysis

Range of international surgical strategies for adolescent idiopathic scoliosis: Evaluation of a multi-center survey

Background

Surgical treatment of adolescent idiopathic scoliosis (AIS) is very complex and modern instrumentation techniques offer multiple possibilities. Despite numerous publications, there is no clear consensus on the optimal strategy for the correction of scoliotic deformities. The goal of this study was to summarize the current surgical strategies for specific AIS cases within various countries.

Method

Thirty-two experienced scoliosis surgeons from 15 countries were asked to plan surgeries on 12 representative AIS cases. All AIS cases had an indication for surgery. A questionnaire was provided to document surgical planning. The surgeons were provided with the patients' age and sex, together with radiographs in the lateral and sagittal planes during upright standing and in lateral bending to the left and right, as well as with clinical images. The angles of the main spinal curvatures were specified in the questionnaire. The surgeons were asked to specify their preferred classification system, their surgical approach, the planned fusion length, the type of implants, the rod type, and the resection steps. The data were analyzed with respect to the inter-rater variability, which was quantified using the Fleiss-Kappa Method.

Results

There was a good agreement (k = 0.61) between the surgeons in choosing the Lenke curve type, and a moderate agreement for the lumbar (0.41) and sagittal (0.56) modifiers. The most frequently planned resection procedure was complete facetectomy (67%). The posterior approach was the most commonly (91%) selected strategy to treat AIS. Anterior approaches were chosen most for Lenke 5 type with a rate of 20%. The upper instrumented vertebra (UIV) varied most for Lenke 1, 5, and 6 cases, with a vertebral level discrepancy of up to 10 levels at Lenke 6. The lowest instrumented vertebra varied most for Lenke 1 and 4 by up to five levels. Polyaxial screws were chosen most (56%), followed by monoaxial (20%) and uniplanar (19%) screws and hooks (5%).

Conclusions

The results highlight the commonalities and discrepancy in the surgical treatment of AIS in between surgeons. The selected LIV and UIV can vary depending on the curve type and surgeon. Hook constructs appear to be generally replaced by transpedicular screws. The survey indicates open questions in the AIS treatment and in the understanding of scoliosis biomechanics.

Long-term adjacent segment degeneration at average 21-year follow-up of posterior instrumented fusion for adolescent idiopathic scoliosis

INTRODUCTION

Posterior instrumented fusion for progressive adolescent idiopathic scoliosis (AIS) is generally considered to have good outcomes, but very long-term reviews are rare. Data on adjacent segment degeneration (ASD) following posterior instrumented thoracic fusion for AIS are lacking. The primary aim was to assess the incidence of ASD and to correlate this with radiographic measures and patient-reported outcome measures (PROMs). The secondary aim was to assess maintenance of curve correction at very long-term follow-up.

METHODS

This single-surgeon consecutive case series of 47 AIS patients was identified from a prospectively collated dataset. As the primary outcome, ASD was assessed radiographically using the Mimura grading system. Pulmonary function tests and PROMs were assessed along with secondary radiographic outcome measures.

RESULTS

Radiographic follow-up was achieved in 77% (36/47) of patients at an average of 21 years (range, 16.5-26.5 years) after surgery. Radiographic evidence of ASD was seen in 64%. PROMs showed a mean Oswestry disability index of 12.1% with an overall Scoliosis Research Society 22 score averaging at 3.7 out of 5. The Coronal Cobb Angle was corrected from an average of 57° preoperatively to 19° immediately postoperatively, deteriorating to 22° at final review, maintaining a 61% curve correction.

CONCLUSIONS

Radiographic evidence of ASD was found in 64% of the cohort. The patient-reported outcome measures were good, with few limitations to activities.

Systematic Review and Meta-analysis: Does Anterior-Posterior Spinal Fusion Still have a Role in Severe Thoracic Adolescent Idiopathic Scoliosis?

Background

Debate exists as to whether anterior-posterior spinal fusion (APSF), rather than posterior-only spinal fusion (PSF), provides benefit for treating severe thoracic adolescent idiopathic scoliosis (AIS). This systematic review and meta-analysis compare (1) Cobb angle correction, (2) complication and reoperation rate, (3) pulmonary function, (4) number of fused segments, and 5) patient-reported outcome measures (PROMs) in both groups.

Methods

Electronic databases were searched to identify studies that met the following inclusion criteria: comparative studies (level 3 or above), severe thoracic curves (≥ 70°), age ≤ 16, AIS aetiology, Lenke 1-4 curves and follow-up ≥ 1 year for ≥ 95% of patient population. Literature was graded for quality and bias using GRADE and MINORS criteria.

Results

Eight studies were included, defined by GRADE as low or moderate level evidence. Three studies showed superior curve correction in the APSF group; however, the meta-analysis showed no significant difference in curve correction between groups (95% CI - 3.45-12.96, P = 0.26). There were more complications in the APSF group, without statistical significance (95% CI 0.53-3.39, P = 0.54; I 2 = 0%, P = 0.78). There were no re-operations in either group. Two studies reported pulmonary function; one showed better function in the APSF group, the other better function in the PSF group. One study showed fewer fused segments in the APSF group, however, no significance was observed in the meta-analysis (95%CI - 1.65-0.31, P = 0.18). Three studies reported PROMs with no differences reported between groups.

Conclusions

APSF and PSF have been found to have comparable results. The present evidence cannot support recommendations for guidelines on future practice with regards to effect on curve correction, complications, re-operations, pulmonary function or PROMs.

Level of evidence

Level III, Systematic review of Level-III studies.

The Sagittal Plane in Spinal Fusion for Adolescent Idiopathic Scoliosis

Sagittal balance is widely recognized as the primary determinant of optimal outcomes in adult spinal deformity. In adolescent idiopathic scoliosis (AIS), coronal correction risks being obtained at the expense of sagittal malalignment after posterior spinal fusion. Apical lordosis, often underestimated on two-dimensional imaging, is the primary deforming factor in AIS. Failure to restore thoracic kyphosis and lumbar lordosis during posterior spinal fusion contributes to problematic early surgical complications, including proximal or distal junctional kyphosis and failure. Although adolescent patients often compensate for sagittal imbalance in the short-term and mid-term, late sequelae of iatrogenic sagittal imbalance include flatback syndrome, disk degeneration, cervical kyphosis, and late decompensation. Objective criteria using spinopelvic parameters and preoperative three-dimensional planning can guide sagittal plane correction during PSF for AIS. Technical caveats can help avoid sagittal plane complications, including instrumentation level selection, anchor type, and anatomic protection of adjacent levels. Other surgical techniques to optimize restoration of thoracic kyphosis include higher implant density, stiffer rod material, Ponte osteotomies, and deformity correction technique.

Long-term experience with simultaneous prone video-assisted thoracoscopic anterior spinal release and posterior spinal fusion in severe rigid pediatric spinal deformities

PURPOSE

While posterior-alone techniques have been successful for most pediatric spinal deformities, anterior spinal release may be useful for severe rigid deformities. Traditional lateral-positioned video-assisted thoracoscopic surgical release (VATSR) followed by prone posterior spinal fusion (PSF) has been criticized for adding extensive operative morbidity. We aimed to reduce its disadvantages by performing prone VATSR and PSF simultaneously and evaluate its long-term outcomes.

METHODS

All consecutive patients from 1991 to 2012 undergoing VATSR and PSF at one institution were retrospectively reviewed. The inclusion criteria comprised severe rigid thoracic scoliosis (> 70°, bending correction > 45°) or kyphosis (> 75°, bolster correction > 45°), and a minimum 2 year follow-up. Demographics, operative data, hospital stay, and radiographic correction data were compared between patients who had undergone sequential VATSR followed by PSF and those who had undergone these procedures simultaneously.

RESULTS

Of 153 patients who had undergone VATSR and PSF, 53 met the inclusion criteria (31 sequential, 22 simultaneous; average follow-up, 50 [range, 24-86] months). Age, preoperative measurements and flexibility, and perioperative complications did not differ significantly. The simultaneous group showed significantly lower operative time (449 vs. 618 min), blood loss (1039 vs. 1906 cc), and hospital stay (6.3 vs. 8.5 days) (all, p < 0.05). Postoperative radiographic correction and maintenance at the final follow-up showed a non-significant trend favoring the simultaneous group.

CONCLUSION

Our simultaneous prone VATSR and PSF technique showed significantly lower operative time, blood loss, and hospital stay compared with the traditional sequential VATSR and PSF method, suggesting its value in treating rigid deformities.