Abstract
Objective: Surgical correction of late-onset idiopathic scoliosis (AIS) has been shown to be effective in obtaining correction in the frontal and sagittal planes, but is of questionable benefit in reducing the rib hump in the transverse plane The purpose of this study was to assess the effects of double rod and pedicle screw (AO USS) instrumentation on transverse plane asymmetry (on the convex and concave side of the scoliosis) in a single thoracic curve type (King III).
Design: A consecutive, prospectively studied cohort treated by a single surgeon with either a single-stage or two-stage procedure.
Subjects: Sixty-five patients with a King III adolescent idiopathic scoliosis were studied. There were 53 females and 12 males whose mean age at surgery was 14.5 years (range 11.1 to 17.9). A single-stage posterior fusion with instrumentation was performed in 46 patients whose mean Cobb angle at surgery was 56° (range 35 to 84). A two-stage procedure with thoracotomy and anterior spine release by multiple disc excisions (mean 6 levels) combined with internal costoplasty (mean 6 ribs), followed one week later by posterior spinal fusion with instrumentation, was performed in 15 patients whose mean Cobb angle was 78° (range 40 to 92).
Outcome measures: All patients were assessed both radiographically and by Integrated Shape Imaging System (ISIS) surface topography pre-operatively, postoperatively (mean of 14 weeks) and at follow-up visits for a mean 2.7 years (range 1.5–6.1).
Results: There were no non-unions or instrument failures in either group.
Single-stage group: Post-operative improvement in the Cobb angle was a mean 54% with a mean 2° loss in correction at final follow-up. ISIS showed the angle of rib hump elevation (convexity side) was improved by a mean of 2.1° and the angle of rib depression (concavity side) was unchanged. At final follow-up the angle of rib hump elevation had recurred by a mean of 3.6° beyond the original pre-operative value. The angle of rib depression remained unchanged.
Two-stage group: Post-operative improvement in the Cobb angle was a mean 64% with a mean 1° loss in correction at final follow-up. ISIS showed the angle of rib hump elevation (convexity side) was improved by a mean of 6.2° and the angle of rib depression (concavity side) was improved by a mean of 3.5°, producing a more balanced transverse plane. At final follow-up the angle of rib hump elevation only recurred by a mean 2.2°. This was compensated by a further improvement in the angle of rib depression by a mean of 2.5°, producing a further correction to balance the transverse plane.
Conclusions: Single-stage surgery is not effective in improving the transverse plane deformity. Two-stage surgery improves the transverse plane deformity on both the convexity and concavity producing a more balanced spine with further improvement due to an improvement of the rib depression (concave side) during follow-up (growth).
Abstracts prepared by Mr. A. J. Stirling, FRCS, and Miss A. Weaver. Correspondence should be addressed to Miss A. Weaver at the Research and Teaching Centre, Royal Orthopaedic Hospital, Northfield, Birmingham, B31 2AP, UK
BritSpine 2002, the second combined meeting of the British Association of Spinal Surgeons, the British Cervical Spine Society, The British Scoliosis Society and the Society for Back Pain Research, took place at the International Convention Centre in Birmingham UK between 27th February and 1st March 2002. The following presentations and posters were given and displayed.
