Abstract
Background: Lenke 1 curves can be treated by a selective thoracic fusion. The lumbar curve, if flexible, can spontaneously correct itself in terms of the Cobb angle and the apical vertebral translation. De-rotation of the thoracic spine with current instrumentation systems has been reported. However, it is unclear what effect this would have on the un-instrumented lumbar curve.
Objective: We report on the changes in the apical rotation (AVR) of the un-instrumented lumbar curve following selective thoracic fusion in Lenke 1B and 1C curves.
Methods and patients: 32 patients with idiopathic scoliosis underwent a selective thoracic fusion for a Lenke 1B or 1C curves. We assessed the apical vertebral rotation of the lumbar curve before and after the selective thoracic fusion. This was measured by the Pedriolle method on the pre-, and post-operative erect radiographs. Cobb angle of the thoracic and lumbar curves before and after the fusion were also measured.
Results: The apical lumbar rotation changed form a mean of 10.7 deg (pre-op) to 7.33 deg (post-op), with a correction index of 19.8 %. The Cobb angle of the instrumented thoracic curve changed from a mean of 54.4 deg (pre-op) to a mean 24.9 deg (postop), the mean correction index was 52.9 %. The mean Cobb angle of the un-instrumented lumbar curve changed from 29.36 deg (pre-op) to 17.76 deg (post-op), with a correction index of 38.8 %.
Conclusion: Selective thoracic fusion of Lenke 1B and 1C leads to an improvement of the rotation un-instrumented lumbar curve.
Correspondence should be addressed to Sue Woordward, Britspine Secretariat, 9 Linsdale Gardens, Gedling, Nottingham NG4 4GY, England. Email: sue.britspine@hotmail.com
