Difficulties are often encountered in the determination of the decompression levels of mult: intervertebral stenosis. We conducted a study on multilevel decompression in 117 cases with lumbar spinal canal stenosis. Each case was classified according to the type of neurogenic intermittent claudication. The range of decompression levels was determined in intraoperative findings.
For the radicular type where the SNRB is effective only in one-level, signs of compression were found in 50% of the additional decompression cases. On the other hand, 29% of the effective multi-vertebral decompression cases had levels without compression. A total of 70% of the caudal type and the mixed type cases showed multi-vertebral compression, wheress 30% had levels with fewer signs of compression.
In the radicular type cases it was questioned whether decompression should be applied at the level where the SNRB is vague and at the severe stenotic level on the image where the SNRB is ineffective. In the caudal and the mixed type case, it is necessary to rely on image diagnosis because of the lack of precise diagnosis of the level responsible for caude equina symptoms.
In the intra operative findings, we found that further limiting the levels to be decompressed is highly recomended for each type. It is however considered risky to limitlevels of decompression while many other issues remain unsoived. Needless to say, curring in one operation is advisable.
