Abstract
Background: To analyse the effects of surgery on sagittal alignment1 in patients with severe Scheuermann’s kyphosis. To assess the ability of two surgical techniques to prevent loss of correction in the thoracic kyphosis. To assess factors of patient’s Body Mass Index (BMI) and instrumentation level on the risk of adjacent level kyphosis or pullout.
Methods: A retrospective study of 13 consecutive cases of rigid Scheuermann’s kyphosis. Group A: 6 patients with anterior interbody cages. GroupB: 7 patients with interbody autogenous rib graft. All patients were instrumented posteriorly from T2 to L2. Radiographs from initial presentation, pre-operatively, post-operatively and at final follow –up were assessed. The thoracic kyphosis, lumbar lordosis, sagittal balance2 and sacral inclination were measured.
Results: There were 7 males and 6 females with a mean age of 22 years (range 15 to 38yrs). The mean follow-up was 26 months (range 7 to 53 mths). In Group A: the mean preoperative kyphosis was 87° (range 82° to 92° ) and postoperative kyphosis was 45° (range 38° to 60°). The mean loss of correction was 0.3° (range 0° to2°). In Group B: the mean preoperative kyphosis was 83° (range 70° to 100°) while the postoperative kyphosis was 43° (range 30° to 60°). The mean loss of correction was 1.1° (range 0°to 2°) at final follow-up. The mean lumbar lordosis pre-operatively for all patients was 66° (range 62° to 84°) reducing to 48° (range 34° to 82°) following surgery. The mean sacral inclination pre-operatively was 41° (range 18° to 80°) reducing to 32 °(range 14°to 40°) following surgery. The mean sagittal balance preoperatively was −1.1 cm (range +0.1 to −3.5). It reduced postoperatively to −2.2 cm (range +1.5 to −4 cm) and was −1.6cm (range +0.2 to – 3.5cm) at final follow- up. Three patients with BMI greater than 25 had an increased lumbar lordosis at final follow up, with one case of implant failure and 2 cases with lower junctional kyphosis. No patient had an upper thoracic junctional kyphosis. There was no evidence of neurological compromise.
Conclusion: Patients had a mean thoracic kyphosis correction of 41° (49%). This was maintained during follow-up with no significant difference between autograft and cages. Cranially, all patients had instrumentation to T2 and there was no junctional kyphosis. Caudally, three obese patients (BMI > 25) suffered screw pullout (1 patient) or junctional kyphosis (2 patients). Instrumentation to L3 may avoid this complication in this patient group. The lumbar lordosis and sacral inclination reduced immediately postoperatively, with further correction at final follow –up.
The abstracts were prepared by Mr Colin E. Bruce. Correspondence should be addressed to Colin E. Bruce, Consultant Orthopaedic Surgeon, Alder Hey Children’s Hospital, Eaton Road, Liverpool, L12 2AP.
References:
1 Hosman AJ, Langeloo DD, de Kleuver M, Anderson PG, Veth RP, Slot GH. Analysis of the sagittal plane after surgical management for Scheuermann’s disease: A view on Overcorrection and the use of an Anterior release, Spine2002; 27(2): 167–75. Google Scholar
2 LoweTG, Katsen MD. Analysis of sagittal curves and balance after Cotrel – Dubousset instrumentation for kyphosis secondary to Scheueurmann’s disease: a review of 32 patients, Spine1994;19:1680–5. Google Scholar
