Abstract
Background: In adolescents at or near skeletal maturity, correction of severe scoliosis may be facilitated by first mobilising the spine anteriorly before the definitive posterior fusion and instrumentation. There is no dispute that this is effective, but it is significantly more invasive, and carries greater risks. The benefits have been measured in greater reduction in the Cobb angle, but the patient’s real concern is with cosmesis. Surface topography can measure this aspect.
Methods: Retrospective comparison of topographic parameters (before surgery and at 7 days, 6 months, and 2 years after, and at latest review, if more than two years) after one-stage (Group 5, N=10) and two stage (Group 3, N=39) with normal adolescents (Group 1, N=63). Patients operated for adolescent idiopathic scoliosis by one surgeon (FED) were compared with girls referred and then judged normal from the screening programme. Topographic parameters (spinal angle, saggittal profile, asymmetry and trunk balance) and Cobb angles were compared by t-test.
Results: Prior to surgery, both treatment groups differed significantly from the index group on all parameters except saggittal profile; from each other, they differed only in mean Cobb (Group 3: 73.6°, Group 5: 59°) and spinal angles and Suzuki hump sum. After surgery, both groups showed significant mean reduction in most parameters and in final Cobb angle (Group 3: 32.7° (−40.9°), Group 5: 29° (−30°) postoperatively) excepting rib hump, and were not statistically distinguishable. Over two years, there was continued improvement in trunk balance and re-establishment of lumbar lordosis in both groups. Group 5 (single stage) showed a slight recurrence of some asymmetry parameters that was statistically (but perhaps not clinically) significant. All patients had a solid fusion post-operatively.
Conclusion: Ideally, this study would be done prospectively, on a controlled, double-blind, randomised basis, but the numbers required and time involved make this impractical. These two surgical groups were pre-selected on the basis of curve severity, and these results may show that the anterior procedure is necessary to bring Group 3 to the same end-point as Group 5. Alternatively, while the anterior procedure improves the reduction of the Cobb angle, it might be the posterior fusion that rearranges the shape of the back and hence brings about the cosmetic improvement. In conclusion reducing the Cobb angle has been the standard of surgical assessment, but the cosmetic result does not necessarily correlate with this. The possibility that less invasive surgery may give as good a cosmetic outcome is worth discussing, as the savings in time, money and risk would be enormous.
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.
