LUMBAR MICRO-DECOMPRESSION: INTERMEDIATE TERM OUTCOME

Abstract

Decompression of the lumber spine for spinal stenosis is the most commonly performed spinal surgical procedure in patients over 60 years old. The aims of surgery are to relieve compression of the spinal nerves and retain integrity of the structural elements of the spinal column and its function as a supportive structure. In trying to avoid excessive removal of the posterior supportive structures of the spinal column without compromising full and safe decompression of the spinal nerves, techniques are being developed to reduce bone removal but also allow access to the spinal canal.

One such micro-decompression involves a hemi-laminectomy and lateral recess decompression on the more symptomatic side followed by undercutting the spinous processes and decompressing the opposite side from within the canal aided by the use the operating microscope, a high speed burr and a copper moldable retractor to protect the dura and nerves.

We have reviewed our first 100 consecutive patients who have had a spinal micro-decompression over a period of 5 years. 58 Female and 42 male patients are included in this series. Mean age was 65 years. Patients were assessed by a combination of clinical review and self-assessment questionnaires. After a follow-up period of up to five years (mean 3.5 years) we have seen symptomatic late instability develop in four patients requiring a further surgical procedure in two of these. Symptoms typically developed two years after the original operation following an initial improvement in radicular symptoms and back pain.

This compares favourably with published results for wide decompression where re-operation rates of 18% are reported. We have analysed the cases of delayed instability in more detail to evaluate whether the late deterioration could have been predicted.

Micro-decompression is shown to be safe with few complications and has advantages over wide decompression without compromising safety.