Background: To determine whether the operation of LSD destabilizes the lumbar spine and leads to an increase in any pre-existing scoliosis or spondylolisthesis. Lumbar spondylosis, which commonly includes a degenerative listhesis and a scoliosis, is the commonest cause for stenosis in the lumbar spine. The standard operation for spinal stenosis remains a laminectomy with fixation and fusion in the presence of possible instability. The laminectomy, however, destabilises the spine and the instrumented fusion makes it a much bigger operation in patients often not best placed to cope with it. The more limited operation of LSD, which has previously been reported to this society, avoids a simultaneous fusion or instrumentation and has been shown to give long term symptomatic relief (1) Its possible effect on the stability of the spine has not previously been reviewed.

Methods: A retrospective clinical and radiological review of consecutive patients operated on for degenerative spinal canal stenosis with either a pre-existing scoliosis or degenerative listhesis or both. Sixty-one patients (44 female and 17 male) with a mean age at operation of 72.8ys (range: 54–85). Pre-operatively 35patients (57%) had a degenerative listhesis, 14 patients (23%) a lumbar scoliosis and 12 (20%) had both. The mean postoperative follow-up was three years (range from one to fourteen years).

Results: None of the 47 patients with a preoperative degenerative spondylolisthesis had any change in grade of the listhesis. Also no patient developed a new spondylolisthesis.

Of the 26 patients with a preoperative scoliosis, 10 progressed by a mean of 4.9° (range 2°–15°)

Conclusion: The results show that the operation of LSD was not associated with the development of a spondylolisthesis or a further progression of a pre-existing listhesis, and no patient developed a scoliosis. In those who had a scoliosis pre-operatively, 38% progressed and this only to a degree which we believe falls within the natural progression to be expected in such a group of patients. We believe these results support the view that the operation of Limited Segmental Decompression for spinal stenosis does not significantly destabilize the spine, even in a group that would appear most vulnerable, and as such there is no indication in such cases to consider a simultaneous instrumentation and fusion.