How Does the Vertical Expandable Prosthetic Titanium Rib Lengthening Intervals Affect the Clinical Outcome in Early Onset Scoliosis Patients? A Five-Year Follow-Up Study

Background: Untreated early-onset scoliosis (EOS) is often complicated by decreased thoracic expansion growth and pulmonary complications. Various fusion-less techniques have been developed to address these complications, including growing rods and vertical expandable prosthetic titanium rib (VEPTR) devices. To achieve adequate spinal growth, optimal lengthening timing is required. Yet, there are no evidence-based guidelines for these intervals. We aimed to evaluate the clinical outcomes concerning the distraction intervals of surgically untreated EOS patients who underwent VEPTR treatment with a minimum 5-year follow-up. Methods: We conducted a multicentered retrospective review of EOS patients managed with VEPTR and grouped them as those patients who underwent lengthening procedures in intervals of ≤8 months throughout 5 years (ie, group 1) and those who were lengthened in intervals >8 months during the same time frame (ie, group 2). The 8-month average interval cutoff was chosen following the findings of Yang and colleagues. We compared demographic variables, radiographic parameters, pulmonary function tests, 24-item Early Onset Scoliosis Questionnaire (EOSQ) findings, and complication rates between both groups. Results: Our study included 447 patients (158 in group 1 and 289 in group 2) with similar preoperative baseline characteristics. Postoperatively, no statistically significant differences were observed between groups regarding the coronal and sagittal major curve magnitudes, spine height gains (ie, T1-T12, L1-S1, and T1-S1), and the 24-EOSQ results. However, group 1 had a higher postoperative complication rate (P=0.034) than group 2. Conclusions: More frequent lengthening intervals were associated with a higher rate of postoperative complications. Further studies are needed to clarify the optimal timing of these intervals among patients with EOS and their association with the outcomes. Level of Evidence: Level III-therapeutic retrospective study.