INTRODUCTION: The aim of this study is to evaluate the correlation between crosssectional area (CSA) of the lumbar spinal canal and the type of clinical symptoms in patients with lumbarspinal stenosis (LSS) using CT‐myelogram (CTM).
METHODS: Eighty‐eight patients (41males, 47 females, mean age: 70.5 years) who underwent decompression with/without fusion at L4/5 level were evaluated. They were divided into three groups according to the type of preoperative neural symptom. Nerve root group (n=34, mean age: 69.4 years) had intermittent claudication with leg pain caused by unilateral nerve root. Cauda equina group (n=11, mean age: 72 years) had numbness of legs or perianal area or had neurogenic bladder. Mixed type group (n=43, mean age:70.9 years) had symptoms of both nerve root and cauda equina. All patients underwent preoparative CTM of lumbar spine. Cross‐sectional area of the lumbar spinal canal at L4/5 level was measured using CTM.
RESULTS: In some patients with extremely severe spinal canal stenosis which showed total block or subtotal block by myelogram, CSA was unmeasurable. The number of patients who had more severe stenosis (CSA<40mm2) was 8(23.5%) in Nerve root group, 9(81.8%) in cauda equine group, and 28(65.1%) in Mixed type group.
DISCUSSION: The types of clinical symptoms of LSS vary depending on the location of a dorsal root ganglion or severity of stenosis. In this study, a small CSA related to cauda equina lesion. It seems possible that patients with nerve root lesion undergo surgical treatment because of a severe leg pain before symptoms of cauda equina develop. Therefore the percentage of patients with severely small CSA was higher in Cauda equina group. It seems that presence of cauda equina symptoms reveals more severe stenosis.