In patients with a degenerative lumbar spine, stenosis can occur, not only at the entrance zone but also at the mid and exit zones of the nerve root canal. Symptoms of degenerative lumbar stenosis relate to two types, due to either caudal or root involvement. Extracanal (mid and exit zone) lesions are an important cause of failed back surgery. Patients suffering from root symptoms may have an extra-canalicular lesion, especially in senile patients.
We classified stenotic lesions in the degenerative lumbar spine from the viewpoint of extra-canalicular lesions. We diagnosed stenosis from abnormal MRI findings and selective radiculography. Stenotic lesions were classified into three groups; extra-canalicular only, intra- and extra-canalicular, and migrated hernia. The second group of both intra- and extra-canalicular was further classified into three types. Double crush, defined as one root with two lesions at two disc levels; Double root, defined as two roots involved at one disc level and a combined type.
We treated 31 patients surgically according to that classification. Twenty eight patients achieved pain relief after the operations, but 3 patients operated on twice complained of residual leg pain. Osteoplastic facet laminectomy was a useful procedure for exposing the extracanal region and provided a good operative field and safe decompressive method.
抄録全体を表示