Analysis of Segmental Mobility Following a Novel Posterior Apical Short-Segment Correction for Adolescent Idiopathic Scoliosis

Segmental range-of-motion by vertebral level in fused and unfused patients with adolescent idiopathic scoliosis: a systematic review of the literature

PURPOSE

This study aims to understand global and segmental spinal ROM in surgical and nonsurgical AIS patients.

METHODS

This systematic review examined segmental vertebral ROM in AIS patients using PubMed, SPORTDiscus, MEDLINE, and Web of Science until October 8th, 2023. Inclusion criteria were articles on segmental motion in AIS patients, both operative and non-operative, under 18 years old.

RESULTS

Seventeen articles met eligibility criteria from 2511 initially retrieved. All patients (n = 996) had AIS (549 non-operative; 447 were operative), with a frequency-weighted mean age of 15.1 ± 1.6 years and a baseline Cobb angle of 51.4 ± 13.3 degrees. Studies showed heterogenous segmental flexibility in the unfused spine, with the apical curve and upper thoracic segments being more rigid and lower segments more flexible at -5 disk segments from the apex. Most studies showed a predictable loss of motion in fused spinal regions postoperatively and a variable loss of global motion depending on the LIV and number of fused segments. A 7° global loss of total trunk flexion per level was observed with increasingly caudal LIV, starting at L1. Anterior vertebral body tethering (AVBT) preserved motion post-surgery but reduced coronal plane motion. AVBT saw less motion loss compared to posterior spinal fusion (PSF) but had higher revision and complication rates.

CONCLUSION

Preservation of spinal segments correlated with improved motion postoperatively. Increasing caudal LIV in PSF showed sagittal flexion loss. AVBT preserved more sagittal ROM than PSF but increased coronal motion loss, complications, and revision rates, with the largest benefit at LIV L4. Data on segmental motion are limited and further research on postoperative segmental ROM is required.

Can anterior vertebral body tethering provide superior range of motion outcomes compared to posterior spinal fusion in adolescent idiopathic scoliosis? A systematic review

PURPOSE

Anterior vertebral body tethering (AVBT) was introduced as a fusionless alternative to treating adolescent idiopathic scoliosis (AIS) while preserving range of motion (ROM). This is the first systematic review to compare the ROM outcomes between AVBT and PSF in treating AIS.

METHODS

We conducted a comprehensive search on PubMed, EMBASE, MEDLINE, and Cochrane Library. Inclusion criteria were patients with AIS treated with AVBT or PSF or both, and clearly defined ROM outcomes; exclusion criteria were scoliosis other than AIS, biomechanical or cadaveric studies, non-English publications, case reports, conference summaries, unpublished literature, commentaries, and reviews. Primary outcome was ROM. Secondary outcomes included Cobb angle correction, quality of life (QOL), complications, and muscle strength and endurance.

RESULTS

Twelve studies were included in this review. We found moderate evidence to support that AVBT results in superior ROM outcomes than PSF while achieving comparable Cobb angle correction with low evidence. The comparison of QOL outcomes between AVBT and PSF remained inconclusive. In addition to the complications noted conventionally in PSF, AVBT could result in over-correction and distal adding-on. We also found very low evidence to support that AIS patients treated with AVBT have superior muscle strength and endurance when compared to those treated with PSF.

CONCLUSIONS

AVBT provides better preservation of ROM and muscle strength postoperatively when compared with PSF, while achieving comparable curve correction. Future studies should explore the spinal growth trajectory to determine the window of opportunity for AVBT in AIS.

A high degree of variability exists in how "safety and efficacy" is defined and reported in growing rod surgery for early onset scoliosis: a systematic review

Established criteria for reporting safety and efficacy have not yet been defined in growing rod surgery for early onset scoliosis. A systematic literature review revealed a high degree of variability in how authors stratified complications and patient outcomes as a means to define safety and efficacy for this challenging patient population.

INTRODUCTION

Several publications have reported the safety and efficacy of traditional growing rods (TGR) and magnetically controlled growing rods (MCGR) using various parameters. Radiographic parameters are most commonly used to measure efficacy, while incidence and type of complications are used to assess safety. A systematic review of peer-reviewed articles was performed to identify whether a consensus exists in how safety and efficacy parameters are reported in EOS patients treated with TGR and MCGR.

HYPOTHESIS

There is no consensus on the parameters used for reporting safety and efficacy in growing rod treatment for early onset scoliosis.

STUDY DESIGN

Systematic literature review.

METHODS

Four databases were searched on November 10, 2016 to identify all qualified peer-reviewed articles using specific keyword searches. All peer-reviewed articles published in English language reporting any data related to safety and efficacy of the TGR and/or MCGR surgical technique were included. Articles that met the inclusion criteria were scored by modified Downs and Black scoring system (J Epidemiol Community Health 52(6):377-384, 1998) for non-randomized studies. All reported safety and efficacy data were extracted and analyzed.

RESULTS

Search of the databases resulted in 111 unique citations including: PubMed (50), Embase (68 with 21 duplicates), Web of Science (29 with 15 duplicates), and CINAHL (15; all duplicates). Fifty-six of 111 citations were excluded during the review of the titles and abstracts. In addition, 16 citations were excluded at the time of full manuscript review. The remaining 39 articles included 23 TGR (2007-2016) and 16 MCGR papers (2012-2016). The overall Downs and Black score was 63.9 for TGR papers vs. 64.0 for MCGR papers (p = 0.97). Efficacy measures were not consistently reported among the publications. The only consistently reported efficacy parameter in majority (> 90%) of papers was curve size. Complication reporting was highly variable.

CONCLUSION

Major curve size was the only consistent parameter to report efficacy in peer-reviewed TGR and MCGR publications. Since complications were not consistently reported, assessing safety of either treatment was infeasible. Establishing standardized safety and efficacy parameters in growing rod surgery for EOS would improve the quality of future studies and makes comparison of different treatment modalities possible. Indeed, other clinically relevant parameters such as health-related quality of life, pulmonary function, nutritional status, and psychiatric and developmental health should also be considered to improve the future safety and efficacy reporting.

Preservation of Spine Motion in the Surgical Treatment of Adolescent Idiopathic Scoliosis Using an Innovative Apical Fusion Technique: A 2-Year Follow-Up Pilot Study

Background

This trial reports the 2-year and immediate postremoval clinical outcomes of a novel posterior apical short-segment (PASS) correction technique allowing for correction and stabilization of adolescent idiopathic scoliosis (AIS) with limited fusion.

Methods

Twenty-one consecutive female AIS patients were treated at 4 institutions with this novel technique. Arthrodesis was limited to the short apical curve after correction with translational and derotational forces applied to upper and lower instrumented levels. Instrumentation spanned fused and unfused segments with motion and flexibility of unfused segments maintained. The long concave rods were removed at maturity. Radiographic data collected included preoperative and postoperative data for up to 2 years as well as after long rod removal.

Results

All 21 patients are beyond 2 years postsurgery. Average age at surgery was 14.2 years (11-17 years). A mean of 10.5 ± 1 levels per patient were stabilized and 5.0 ± 0.5 levels (48%) were fused. Cobb angle improved from 56.1° ± 8.0° to 20.8° ± 7.8° (62.2% improvement) at 1 year and 20.9° ± 8.4°, (62.0% improvement) at 2 years postsurgery. In levels instrumented but not fused, motion was 26° ± 6° preoperatively compared to 10° ± 4° at 1 year postsurgery, demonstrating 38% maintenance of mobility in nonfused segments. There was no report of implant-related complications.

Conclusions

PASS correction technique corrected the deformity profile in AIS patients with a lower implant density while sparing 52% of the instrumented levels from fusion through the 2-year follow-up.

Comparison of low density and high density pedicle screw instrumentation in Lenke 1 adolescent idiopathic scoliosis

BACKGROUND

The correlation between implant density and deformity correction has not yet led to a precise conclusion in adolescent idiopathic scoliosis (AIS). The aim of this study was to evaluate the effects of low density (LD) and high density (HD) pedicle screw instrumentation in terms of the clinical, radiological and Scoliosis Research Society (SRS)-22 outcomes in Lenke 1 AIS.

METHODS

We retrospectively reviewed 62 consecutive Lenke 1 AIS patients who underwent posterior spinal arthrodesis using all-pedicle screw instrumentation with a minimum follow-up of 24 months. The implant density was defined as the number of screws per spinal level fused. Patients were then divided into two groups according to the average implant density for the entire study. The LD group (n = 28) had fewer than 1.61 screws per level, while the HD group (n = 34) had more than 1.61 screws per level. The radiographs were analysed preoperatively, postoperatively and at final follow-up. The perioperative and SRS-22 outcomes were also assessed. Independent sample t tests were used between the two groups.

RESULTS

Comparisons between the two groups showed no significant differences in the correction of the main thoracic curve and thoracic kyphosis, blood transfusion, hospital stay, and SRS-22 scores. Compared with the HD group, there was a decreased operating time (278.4 vs. 331.0 min, p = 0.004) and decreased blood loss (823.6 vs. 1010.9 ml, p = 0.048), pedicle screws needed (15.1 vs. 19.6, p < 0.001), and implant costs ($10,191.0 vs. $13,577.3, p = 0.003) in the LD group.

CONCLUSIONS

Both low density and high density pedicle screw instrumentation achieved satisfactory deformity correction in Lenke 1 AIS patients. However, the operating time and blood loss were reduced, and the implant costs were decreased with the use of low screw density constructs.