A New Look at Vertebral Body Tethering (VBT): Through the Modified Clavien-Dindo-Sink (mCDS) Classification.

INTRODUCTION: Anterior vertebral body tethering (AVBT) is increasingly popular as an option for surgical treatment of idiopathic scoliosis (IS). While the technology remains new, it is important for families and patients to be able to compare it to the current standard of care, posterior spinal fusion (PSF). The purpose of this study is to describe the complication rate of AVBT in IS using the mCDS and to compare it to the recently reported complication rate of PSF in IS. METHODS: A multicenter pediatric spine deformity database was queried for all idiopathic scoliosis patients who underwent vertebral body tethering. There were 171 patients with a minimum 9-month follow-up included in this study. Complications were retrospectively graded by 2 attending pediatric spine surgeons using the mCDS classification system. RESULTS: Data from 171 patients with idiopathic scoliosis was available for analysis, with 156/171 (91%) of patients being female and an average age of 12.2 years old at surgery. There were 156 thoracic tethers (1 with an LIV below L2), 5 lumbar tethers, 9 staged double tethers, and only 1 patient with same-day double tether. Fifty-five (55) (32%) patients experienced a total of 69 complications. The most common complication type for VBT by mCDS was Grade IIIb, encompassing 29/69 (42%) of complications. The second most frequent complication grade was Grade I at 23/69 (33%). Thirty-four (34) out of 69 (49%) of the VBT complications reported required either procedural/surgical intervention or admission to the ICU. CONCLUSIONS: This is the first study to directly compare the complication profile of VBT to PSF using the mCDS. Forty-nine percent (49%) of the VBT complications reported were at least Grade III, while only 7% of complications in the control PSF cohort from the literature were Grade III or higher. The mCDS complication classification brings light to the early learning experience of a new technique compared to the widely accepted standard of PSF for IS. LEVEL OF EVIDENCE: III - Retrospective comparative study.

Failure to lengthen consensus for the magnetically controlled growing rod (MCGR).

INTRODUCTION: MCGR lengthening has become an important innovation in treating patients with EOS. An alternative to traditional growing instrumentation, a single surgical procedure is necessary for insertion of the construct, followed by non-invasive lengthening in the outpatient setting. With every new technology emanates a new complication to troubleshoot. Failure to lengthen in the MCGR is a significant cause of revision surgery. Currently, no consensus exists on how to define a MCGR lengthening failure, what steps are necessary after a failure to lengthen, and what factors determine these next steps. The primary goal of this study was to establish a consensus on how to define and navigate a MCGR that fails to lengthen. METHODS: A series of 3 surveys were distributed to 49 early onset scoliosis surgeons with 37 responses between December 2021 and April 2022. Consensus was defined as at least 70% agreement. RESULTS: 37 of 49 surgeons (75%) responded to the first survey, and all 37 surgeons responded to the following two surveys (100%). Consensus statements were reached on 25% of questions (3/12) from survey 1, 40% of questions (4/10) on survey 2, and 100% of questions (5/5) on survey 3. The questions that reached consensus are detailed in Table 1. Consensus steps to navigate a rod that fails to lengthen 1 mm (97%) in the office include retrying during the same visit (78%), changing technique in the office (88%), and not adjusting the interval between lengthening appointments (78%). Table 1 Items that reached consensus from each survey (12 total) Survey Question Response, Consensus Percentage 1 If a rod does not lengthen, do you try again in that office visit?​ Yes, 78% 1 All modes of XR are equivalent when determining failure to lengthen? Yes, 70% 1 If you are unsuccessful at lengthening, you should change the lengthening interval? No, 78% 2 Re-lengthening a rod following a failure to lengthen one should change their technique? Yes, 88% Reposition patient, 100% Alternate rods, 90% No traction in OR, 92.6% 2 Is a MCGR non-operational following 3 consecutive visits where the rod failed lengthening? Yes, 100% 2 Considerations when determining next steps with a non-operational rod? Skeletal Age, 100% Curve Progression, 97% Curve Stiffness, 93.8% Family Convenience, 83% Chronologic Age, 77% Time from Last Lengthening, 70% 2 Can an APP follow your protocol for a rod that has failed to lengthen? Yes, 81% 3 Are you comfortable using either clunk or stall to describe the phenomena of the internal clutch failing within the actuator when lengthening? Yes, 97.3% 3 Clunk/stall try again before an adjustment? Yes, 81% 3 Define failure to lengthen? Less than 1 mm length achieved, 97% 3 After two failure to lengthen events do you discuss next surgical steps?​ Yes, 97% 3 Once a rod had been classified as non-operational (no longer lengthening despite interventions) do you consider the underlying diagnosis when making next step decisions? Yes, 97% CONCLUSION: Best clinical practice guidelines using a Delphi method established a consensus on defining failure to lengthen in a MCGR (less than 1 mm), appropriate responses to failure to lengthen (re-attempt to lengthen and re-position patient) and a definition for a non-functional MCGR (failure to lengthen 3 consecutive times). This consensus will help standardize research on this important problem. LEVEL OF EVIDENCE: V-expert opinion.

Impact of Social Determinants of Health on Adolescent Idiopathic Scoliosis Curve Severity.

INTRODUCTION: Social determinants of health have been shown to influence the health and outcomes of pediatric patients. Adolescent idiopathic scoliosis (AIS) may be particularly sensitive to such factors as early diagnosis and treatment can obviate the need for surgical intervention. The purpose of this study was to analyze the effect that social determinants of health have on the severity of AIS at presentation and at the time of surgery. METHODS: A retrospective review was conducted for consecutive patients who underwent posterior spinal fusion for AIS from 2020 to 2022. Demographic data was collected, while insurance status (private vs. public) and childhood opportunity index (COI) categories (LOW vs. HIGH) were used as a proxy for socioeconomic status. Curve magnitude at the initial presentation and at the latest preoperative visit were recorded with a threshold of 25 to 40 degrees considered within the bracing range. Univariate and multivariate analysis was done to compare differences between subgroups as appropriate. RESULTS: A total of 180 patients with mean initial and preoperative major curve angles of 48 and 60 degrees were included. Statistically significant differences in race and insurance types were appreciated, with the LOW COI group having a higher proportion of underrepresented minority and publicly insured patients than the HIGH COI group ( P <0.001). Patients within the LOW COI group presented with an initial curve that was, on average, 6 degrees more severe than those within the HIGH group ( P =0.009) and a preoperative curve that was 4 degrees larger than those within the HIGH group ( P =0.015). Similarly, only 13% of patients within the LOW COI group presented with curves within the bracing threshold, compared with 31% in the HIGH COI group ( P =0.009). CONCLUSION: Socioeconomic status plays a significant role in the severity of AIS. Specifically, patients with lower COI tend to present with curve magnitudes beyond what is responsive to nonsurgical treatment, leading to larger curves at the time of surgery. Future work should focus on addressing social inequalities to optimize the treatment and outcomes of AIS patients. LEVEL OF EVIDENCE: Level III- Retrospective Comparative Study.