Anterior Vertebral Body Tethering: A Single-Center Cohort with 4.3 to 7.4 Years of Follow-up.

BACKGROUND: Vertebral body tethering (VBT) is a well-recognized, non-fusion alternative for idiopathic scoliosis in children with growth remaining. To date, there have been almost no published outcome studies with postoperative follow-up of >2 years. We aimed to fill this gap by evaluating mid-term outcomes in our first 31 consecutive patients. METHODS: We retrospectively assessed additional clinical and radiographic data (mean, 5.7 ± 0.7 years) from our first 31 consecutive patients. Assessments included standard deformity measures, skeletal maturity status, and any additional complications (e.g., suspected broken tethers or surgical revisions). Using the same definition of success (i.e., all residual deformities, instrumented or uninstrumented, ≤30° at maturity; no posterior spinal fusion), we revisited the success rate, revision rate, and suspected broken tether rate. RESULTS: Of our first 31 patients treated with VBT, 29 (of whom 28 were non-Hispanic White and 1 was non-Hispanic Asian; 27 were female and 2 were male) returned for additional follow-up. The success rate dropped to 64% with longer follow-up as deformity measures increased, and the revision rate increased to 24% following 2 additional surgical revisions. Four additional suspected broken tethers were identified, for a rate of 55%, with only 1 occurring beyond 4 years. No additional patients had conversion to a posterior spinal fusion. We observed a mean increase of 4° (range, 2° to 8°) in main thoracic deformity measures and 8° (range, 6° to 12°) in thoracolumbar deformity measures. CONCLUSIONS: With >5 years of follow-up, we observed a decrease in postoperative success, as progression of the deformity was observed in most subgroups, and an increase in the revision and suspected broken tether rates. No additional patients had conversion to a posterior spinal fusion, which may indicate long-term survivorship. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Measuring treatment adverse event burden in myasthenia gravis: Single-center prospective evaluation utilizing the Adverse Event Unit (AEU).

INTRODUCTION/AIMS: We developed a patient- and physician-weighted consensus unit called the adverse event unit (AEU) that quantifies and compares adverse event (AE) burden among any group of medications in neurological patients. In this study we evaluated preliminary validity and feasibility of measuring AE burden with the AEU in myasthenia gravis (MG). METHODS: This is a single-center, prospective, 1-year, observational study of adult MG patients presenting for routine care between April 1, 2021 and March 31, 2022. The MG Activities of Daily Living (MG-ADL), the 15-item MG Quality of Life revised (MG-QOL15r), MG-Composite, and AEU scores were obtained at all visits. A priori primary feasibility metric was AEU completion rate equal to (within 3.8%, one-sided 95% confidence interval [CI]) or better than MG-ADL completion rate. Time to administer AEU and MG-ADL/MG-QOL15r, correlation between AEU total score and MG-QOL15r, and median AEU scores for each MG medication were evaluated. RESULTS: Fifty-four patients completed 67 study visits; side effects were reported at 75% of the visits. The study met the primary feasibility endpoint; AEU and MG-ADL were recorded at all visits. Times to administer the AEU (median 5 minutes) and MG-ADL/MG-QOL15r were similar. We observed a weak correlation of 0.29 (95% CI 0.03 to 0.51, P = .032) between AEU and MG-QOL15r scores. Non-statistically significant differences in median AEU scores were observed among MG medications. DISCUSSION: Our data demonstrate preliminary feasibility and validity of using the AEU to measure AE burden in MG. Future studies will compare AE burden among MG treatments and evaluate clinically meaningful AEU scores in MG.

Central Airway Obstruction with Persistent Pulmonary Decline After Vertebral Body Tethering: A Case Report.

CASE: An 11-year-old girl with pectus excavatum presented with an acute airway obstruction and persistent pulmonary compromise after vertebral body tethering (VBT). The anterior instrumentation was occluding her right basilar bronchus, resulting in hyperinflation. Removal of the instrumentation reversed the hyperinflation. CONCLUSION: This case illustrates the difficulty of performing VBT in a small patient with severe scoliosis and significant asymmetric pectus excavatum. We recommend using low-profile instrumentation and ensuring the trajectory of the instrumentation is anterior to the rib head and parallel to the articular facets.

Team Integrated Enhanced Recovery (TIGER) Protocol after Adolescent Idiopathic Scoliosis Correction Lowers Direct Cost and Length of Stay While Increasing Daily Contribution Margins.

Introduction: Posterior spinal fusion (PSF) is the gold standard procedure for curve correction in Adolescent Idiopathic Scoliosis (AIS). Enhanced recovery protocols (ERPs) have been found to decrease pain and hospital length of stay (LOS) resulting in decreased total hospital charges. Methods: We identified all adolescent idiopathic scoliosis patients treated with a posterior spinal fusion at our children's hospital between 2015-2019. Length of stay, pain scores, and hospital direct costs were calculated to determine the pathway's efficacy. Results: Hospital LOS was reduced by 26% and post-op pain scores did not significantly change when using the Team Integrated Enhanced Recovery (TIGER) protocol (P<0.05). Total hospital costs decreased by 7.9%, daily contribution margins increased 7.9%, and daily net income increased 10.6% after TIGER protocol implementation. Conclusion: TIGER protocol resulted in decreased hospital LOS as well as direct costs for the hospital without increasing postoperative pain scores.

A preliminary assessment of intervertebral disc health and pathoanatomy changes observed two years following anterior vertebral body tethering.

PURPOSE: Vertebral body tethering (VBT) has been reported as a safe and effective non-fusion surgical technique for the treatment of adolescent idiopathic scoliosis, but the postoperative health of the bone and soft tissues of the spine following instrumentation remains unknown. We aimed to evaluate pathoanatomy and degenerative changes of the spine in adolescent idiopathic scoliosis patients both prior to and two years following VBT. METHODS: We prospectively enrolled nine patients who underwent VBT for the treatment of progressive adolescent idiopathic scoliosis. All patients received preoperative and two-year postoperative magnetic resonance imaging of their spine; images were assessed for pathoanatomy (e.g. nucleus pulposus positioning and muscle atrophy) and degenerative changes (e.g. Schmorl nodes, endplate oedema, disc degeneration, and osteoarthritis) at each vertebral level between T1 and S1. RESULTS: Four patients (44%) exhibited a shift of the nucleus pulposus from an eccentric position at baseline towards midline at three or more levels, most of which were in the tethered region. Tethering did not affect preexisting fatty atrophy of multifidus. No patients exhibited postoperative Schmorl nodes, endplate oedema, or disc degeneration in either the tethered or untethered regions. Four patients (44%) presented with mild facet osteoarthritis in the lower lumbar spine, which did not change postoperatively. One patient developed moderate facet osteoarthritis at L5-S1. CONCLUSIONS: These preliminary data indicate that VBT may not result in significant degenerative changes in either the intervertebral discs or the posterior facets two years following instrumentation.

Anterior Vertebral Body Tethering for Adolescent Scoliosis with Growth Remaining: A Retrospective Review of 2 to 5-Year Postoperative Results.

BACKGROUND: Anterior vertebral body tethering (VBT) is an early treatment option for progressive scoliosis in pediatric patients, allowing for continued deformity correction during normal growth. We report postoperative radiographic and clinical outcomes for patients treated with VBT. METHODS: This clinical and radiographic retrospective review of 31 consecutive patients included an analysis of preoperative, perioperative, and postoperative details, including the Lenke classification; Cobb angle measurements of the proximal thoracic, main thoracic, and lumbar curves; the sagittal profile; and skeletal maturity. Successful outcomes were defined by a residual curve of ≤30° in skeletally mature patients who did not undergo a posterior spinal fusion (PSF). RESULTS: Of the 31 patients treated, 29 met the inclusion criteria, and 2 were lost to follow-up. The mean patient age (and standard deviation) at the time of the surgical procedure was 12.7 ± 1.5 years (range, 10.2 to 16.7 years), with most patients classified as Risser grade 0 or 1 (52%) and Sanders stage 3 (32%). A mean of 7.2 ± 1.4 vertebral levels were instrumented, with a minimum preoperative Cobb angle of 42°. At the latest follow-up, 27 patients had reached skeletal maturity (Sanders stage ≥7) and 20 patients exhibited a curve magnitude ≤30°, for a success rate of 74%. A suspected broken tether occurred at ≥1 level in 14 patients (48%). Two patients underwent PSF and 4 had tether revision. The overall revision rate was 21% (6 of 29). CONCLUSIONS: This study shows the success and revision rates as well as the impact of a suspected broken tether on the procedural success of VBT. Despite our patient population being slightly more mature at the time of the surgical procedure compared with previous studies, we had a higher success rate and a lower revision rate. A PSF was avoided in 93% of patients, indicating that VBT may be a reliable treatment option for adolescent scoliosis in skeletally immature individuals. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.