Abstract
Objective: To evaluate the long term radiological and clinical outcome after posterior correction of adolescent right thoracic idiopathic scoliosis with Cotrel-Dubousset instrumentation (CDI) and Harrington rod instrumentation (HRI).
Design: Retrospective comparative analysis.
Subjects: Out of preoperative standing radiographs of 229 patients 30 pairs of female patients, one patient with Harrington rod instrumentation (HRI) and the other with Cotrel-Dubousset instrumentation (CDI), could be identified. Curves within pairs were comparable with regard to curve magnitude (thoracic and lumbar) and level of stable and neutral vertebrae. Follow up examination included a clinical review, long cassette upright PA and lateral radiographs of the spine and two patient outcome questionnaires. Mean follow up time for CDI patients was 128 months and for HRI patients 198 months respectively.
Outcome measures: The pain questionnaire according to Moskowitz [1] was used to assess back pain. A customized questionnaire was used to assess whether patients were satisfied with their postoperative cosmetic appearance.
Results: In 92 per cent of the patients L2 was the lowest instrumented vertebra. The thoracic Cobb angle in the HRI group was corrected from 64° to 42° (34%) and in the CDI group from 66° to 24° (58%). Group differences were significant (p=0.004). The lumbar Cobb angle in the HRI group was corrected from 41° to 24° (41%) and in the CDI group from 44° to 21° (52%) respectively. Group differences were significant (p=0.03). The lumbar lordosis below the fusion could be improved postoperatively in CDI patients (L2–L5: 31° to 37°), whereas it remained unchanged in HRI patients (L2–L5: 32°). Group differences were significant (p=0.005). The overall cosmetic appearance was better in the CDI group (CDI 76% excellent and good, HRI 71%, p=0.04).
15% of the CDI patients and 24% of the HRI patients reported frequent low back pain episodes. Group differences were significant (p=0.008). A high correlation between incidence of low back pain and low degrees of lumbar lordosis below the fusion was revealed in HRI patients (p=0.02).
Conclusion: With Cotrel-Dubousset instrumentation better correction of the thoracic and lumbar curves in the frontal plane and better restoration of the lumbar lordosis distal the fusion is achievable. The lack of restoration of lumbar lordosis below the fusion in HRI patients may have some impact on the higher incidence of low back pain episodes found in this group. The postoperative cosmetic result was better in patients with Cotrel-Dubousset instrumentation.
The abstracts were prepared by Mr Peter Millner. Correspondence should be addressed to Peter Millner, Consultant Spinal Surgeon, Orthopaedic Surgery, Chancellor Wing, Ward 28 Office Suite, St James’ University Hospital, Beckett Street, Leeds LS9 7TF.
References:
1 Moskowitz A, Moe JH,Winter RB,Binner H. Long-term follow-up of scoliosis fusion. J Bone Joint Surg1980, 62-A:364–76. Google Scholar
