Selective Thoracic Fusion for Adolescent Idiopathic Scoliosis: Long-Term Radiographic and Functional Outcomes*

Abstract

IntroductionSelective thoracic fusions (STFs) were introduced by Moe to treat the structural thoracic curve when a more flexible lumbar component existed. It is unknown how the curves behave and how the patients function beyond 20 years after surgery. MethodsOf the 152 eligible patients with STF, 67 were traced and contacted and 40 completed outcome questionnaires (Oswestry Disability index [ODI], Scoliosis Research Society–30 [SRS-30]) and had follow-up standing radiographs. The preoperative, postoperative, 1-year, and follow-up films were compared, and the lumbar spine on follow-up assessed for signs of degeneration—disc space narrowing, osteophyte formation, rotatory subluxation, and lateral spondylolisthesis. ResultsThe average follow-up was 32.7 years. There were 27 Lenke 1C, 10 Lenke 2C, and 3 Lenke 1B curves. A posterior fusion was performed in 37, with a Harrington rod used in 28 and all-hook constructs in 12 with fusion to T10 (1), T11 (10), T12 (22), or L1 (7). The average preoperative right thoracic curves were 56.1°, 36.2° 1 year postoperation, and 38.6° at follow-up. The average preoperative lumbar curve was 44.6°, being 35.2° at 1 year postoperation, and 36.9° at follow-up. Five patients had additional surgery, 3 pseudarthrosis repairs (one with extension of the fusion to L4), 1 implant removal, and 1 microdiscectomy 35 years postoperatively. At follow-up, the average ODI was 8.7 (0–62) and the average SRS-30 3.8 (1.4–4.9). Nine patients took nonnarcotic medication, usually weekly or less, with only one taking daily narcotics. The most common lumbar radiographic finding was disc space narrowing at the apex of the lumbar curve, and osteophytes at L2–L3. There was no correlation of the lumbar changes to ODI, with a tendency to more medication use with longer follow-up (older subjects). ConclusionAt an average 33-year follow-up, the lumbar curve in STF is unchanged, with patients functioning well and mild radiographic changes in the lumbar spine.