Perioperative Outcomes of Open Anterior Vertebral Body Tethering and Instrumented Posterior Spinal Fusion for Skeletally Immature Patients With Idiopathic Scoliosis

Abstract

Background: Correcting adolescent idiopathic scoliosis (AIS) without fusion can be achieved with anterior vertebral body tethering (AVBT). However, little is known about the perioperative outcomes, pain control, and clinical outcomes in patients undergoing AVBT compared with instrumented posterior spinal fusion (IPSF).

Methods: In this retrospective cohort study, we compared pediatric patients with AIS who underwent either AVBT or IPSF. Inclusion criteria were based on the AVBT group, which included primary thoracic idiopathic scoliosis, Risser ≤1, curve magnitude 40 to 70 degrees, age 9 to 15, no prior spine surgery, index surgery between 2014 and 2019, and minimum 2-year follow-up. Patient demographics, perioperative metrics, pain visual analog scale scores, opiate morphine equivalent usage, cost data, and radiographic outcomes were compared.

Results: We identified 23 patients who underwent AVBT and 24 matched patients in the IPSF group based on inclusion criteria. Patients undergoing AVBT and PSF were similar in age (12±1 y vs. 13±1 y, P =0.132) and average follow-up time (3.8±1.6 y vs. 3.3±1.4 y, P =0.210). There were 23 female patients (87%) in the AVBT group and 24 female (92%) patients in the IPSF group. Intraoperatively, estimated blood loss (498±290 vs. 120±47 mL, P <0.001) and procedure duration (419±95 vs. 331±83 min, P =0.001) was significantly greater in the IPSF group compared with AVBT. Length of stay was lower in the AVBT group compared with PSF (4±1 vs. 5±2 d, P =0.04). PSF patients had significantly greater total postoperative opiate morphine equivalent use compared with AVBT (2.2±1.9 vs. 5.6±3.4 mg/kg, P <0.001). Overall direct costs following PSF and AVBT were similar ($47,655+$12,028 vs. $50,891±$24,531, P =0.58). Preoperative radiographic parameters were similar between both the groups, with a major thoracic curve at 51±10 degrees for AVBT and 54±9 degrees for IPSF ( P =0.214). At the most recent follow-up, IPSF patients had greater curve reduction to a mean major thoracic curve of 11±7 degrees (79%) compared with 19±10 degrees (63%) in AVBT patients ( P =0.002). Nine patients (39%) required revision surgery following AVBT compared with 4 patients(17%) following IPSF ( P =0.09).

Conclusions: In a select cohort of patients, AVBT offers decreased surgical time, blood loss, length of stay, and postoperative opiate usage compared with IPSF. Although IPSF resulted in greater deformity correction at 2-year follow-up, the majority of patients who underwent AVBT had ≤35 major curves and avoided fusion. There is optimism for AVBT as a treatment option for select AIS patients, but long-term complications are still being understood, and the risk for revision surgeries remains high.

Level of evidence: Level III.