DualRod Anterior Spinal Fusion for Adolescent Idiopathic Scoliosis Outcomes at Minimum 5Years Compared to Previous 2Year FollowUp: Paper #10

Zebala, Lukas P. MD; Buchowski, Jacob M. MD, MS; Bridwell, Keith H. MD; Koester, Linda

Spine: Affiliated Society Meeting Abstracts: 2010 - Volume - Issue - p 56
Podium Presentation Abstracts

United States

Summary: Dual‐rod anterior spinal fusion for adolescent idiopathic scoliosis provides significant deformity correction. Coronal and sagittal deformity correction was maintained from 2‐year to average 6‐year follow‐up. While no radiographic evidence of pseudarthrosis was present at 2‐years, 1% of dual‐rod ASF patients developed a pseudarthrosis after their 2‐year follow‐up. Patients with pseudarthrosis did not have significant worsening of their deformity but did trend towards worse SRS pain scores than at 2‐year follow‐up.

Introduction: Our prior study on 60 dual‐rod anterior spinal fusions (ASF) at 2‐years showed improved radiographic and clinical outcomes without pseudarthrosis. This study assesses dual‐rod instrumentation outcomes at a minimum 5‐year follow‐up.

Methods: 92 consecutive patients had dual‐rod ASF by 2 surgeons at 2 hospitals from 7/97‐6/04 and were eligible for analysis. 55 patients (average age 15 yrs) (39/60 in prior study) with thoracic (n=11) (9/18 in prior study) or thoracolumbar/lumbar (n=44) (30/42 in prior study) curves and average 6 year (range, 5‐10 yrs) follow‐up had radiographic and clinical assessment. Pseudarthrosis was diagnosed if instrumentation failure or lack of disc space bridging bone were evident on radiographs.

Results: Dual‐rod ASF maintained deformity correction at last follow‐up compared to 2‐years and coronal and sagittal deformity was significantly improved from preop (Table 1). Clinically, the thoracic and lumbar groups had similar radiographic deformity correction. At 2‐years, no radiographic evidence of pseudarthrosis was present. Between 2‐ and 5‐years, 4 patients (2 from prior 60 patients) had pseudarthrosis on x‐ray. 3 patients lacked complete disc space bridging bone in at least 1 disc space, but had no implant failure. 1 of these 3 patients had complaints of back pain at last follow‐up. 1 patient had implant failure with rod migration and underwent revision surgery. Despite pseudarthrosis, the 4 patients maintained their improved coronal and sagittal deformity correction from 2‐ to 5‐years. There was no significant change in SRS pain, self‐image or function for the Total group. Patients with pseudarthrosis had a trend for worse SRS pain scores at last follow‐up.

Conclusion: This largest single institution study of dual‐rod ASF with minimum 5‐year follow‐up revealed that dual‐rod implants maintained deformity correction from 2‐ to 5‐years. 4 patients had radiographic evidence of pseudarthrosis after 2‐years, but maintained their deformity correction and SRS outcomes from 2‐years. Assessment of fusion for dual‐rod ASF may require a minimum 5‐year follow‐up.

© 2010 Lippincott Williams & Wilkins, Inc.