Abstract
Introduction and Aims: Surgery for degenerative lumbar spondylolisthesis may entail both decompression and fusion. The knee-chest position facilitates decompression, but fixation in this position risks fusion in kyphosis. This can be avoided by intra-operative re-positioning to the fully prone position. We aim to quantify restoration of lordosis achieved by this manoeuvre.
Method: Thirty-six patients with degenerative lumbar spondylolisthesis and stenosis were treated by posterior decompression and interbody fusion with pedicle screw fixation (without interbody cages). There were 16 men and 20 women with a mean age of 58.2 years (32–80). The decompression, interbody grafting and screw insertion were performed with the patient in the knee-chest position. The patient was repositioned to the fully prone position for subsequent fusion. The sagittal plane angle was measured on the pre-operative, intra-operative and post-operative x-rays. Short-Form 36 (SF-36) scores and Visual Analogue Scales (VAS) for pain (0 to 10) were determined pre- and post-operatively.
Results: Twenty-eight patients underwent single-level fusion, two patients had two levels, two patients had three levels and four patients had four levels fused. The mean pre-operative sagittal angle between the operated vertebrae was 15.7 degrees lordosis, and the intra-operative angle before re-positioning was 14.9 degrees. The mean immediate post-operative angle was 23.7, and at six-month follow-up the angle was 23.1. Overall there was a mean increase in lordosis angle after repositioning of 8.0 degrees per operative level (p< 0.01). The mean scores of the SF-36 improved in all eight domains and this was significant (p< 0.05) for social functioning (44.4 to 68.9), energy and vitality (36.0 to 49.5), pain (23.8 to 58.3) and general health perception (51.4 to 65.6). Mean VAS pain scores for back pain improved from 7.47 pre-operatively to 3.84 post-operatively (p< 0.001); and for leg pain improved from 7.56 to 3.78 (p< 0.001). No complications attributable to the manoeuvre occurred.
Conclusion: Lumbar spondylolisthesis was found to be associated with reduction of normal lumbar lordosis. The knee-chest position for surgery exacerbates this loss of lordosis. Intra-operative repositioning restores lordosis to greater than the pre-operative angle, which may improve clinical outcome.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
One or more of the authors are receiving or have received material benefits or support from a commercial source.
