Study design: Multi-institution retrospective review.
Objective: To determine the surgical revision rates of hook, hybrid, anteroposterior, and total pedicle screw constructs for adolescent idiopathic scoliosis (AIS).
Summary of background data: Much debate continues on the safety, efficacy, and cost of thoracic pedicle screws. Nonetheless, there are no large series that have evaluated the revision rate of various constructs in AIS to determine the need for repeat surgery, and therefore, the added indirect costs and risks of additional procedures.
Methods: We retrospectively reviewed the surgical case logs of 1428 patients with AIS at 2 institutions from 1990 to 2004, and the clinical records and radiographs of revision cases. Patients were classified into 1 of 4 groups: hook, hybrid hook and screw, all pedicle screw, and combined anteroposterior fusion constructs. Overall, there were 65 (4.6%) returns to the operating room, or 55 (3.9%) cases after excluding infections without concomitant pseudarthrosis.
Results: Of the 65 revision cases, there were 52 females and 13 males, at an average age at first surgery of 13.9 years (range, 9-18 years), and an average age at revision of 14.7 years (range, 12-23 years). For the revision cases, the average initial Cobb was 61.9 degrees (range 44 degrees -110 degrees ), and this was not statistically different within the cohorts (P > 0.05). In terms of revision rate, all hook constructs had a higher revision rate secondary to instrumentation failure when compared with screws, while both hook and hybrid constructs had an overall higher surgical revision rate when compared with screw constructs or anteroposterior constructs (all P <or= 0.05). The pseudarthrosis rate trended toward, but did not meet, statistical significance between these same groups.
Conclusion: All pedicle screw and anteroposterior constructs have a lower surgical revision rate when compared with hook and hybrid constructs. The hidden patient and financial costs of these findings should be considered when evaluating overall instrumentation efficacy.