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.

Objective: To evaluate the long term results of an operation developed to decompress the roots at the stenotic level, preserve the midline structures, and not use instrumentation or fusion.

Design: A retrospective clinical and radiological review of consecutive patients operated on for spinal stenosis secondary to lumbar spondylosis.

Subjects: One hundred and sixty patients (eighty seven female and seventy three male) with a mean age at operation of sixty eight (range 40–90). Sixty one patients (38%) had a degenerative listhesis causing stenosis. The mean post operative follow-up was twenty two months (range two months to fourteen years).

Summary of background data: Lumbar spondylosis, commonly involving degenerative listhesis, is the commonest cause for spinal stenosis in the lumbar spine. Surgery offers the only permanent cure. The standard procedure remains a laminectomy with fixation and fusion in the presence of possible instability. The laminectomy destabilises the spine and the instrumented fusion makes it a much bigger operation in patients often not best placed to cope with it. There is a need, therefore, for an effective operation that does not compromise spinal stability.

Results: At six weeks one hundred and forty one patient (85%) reported relief of leg pain and a further nine patients were improved at three to six months. 52% of the patients reported a concomitant improvement in back pain. The results were sustained at follow-up.

The operation was not responsible for the development of a new spondylolisthesis. A minimal increase in an existing degenerative listhesis was seen in two patients only without compromise of their good results. There was no revision surgery at any of the operated levels.

Conclusions: The operation of segmental spinal decompression for degenerative lumbar spinal stenosis has been found to be effective, safe, and give good long term results, without compromising the existing spinal stability. Patient selection and attention to operative technique are essential.