[The arthritic narrow lumbar canal. Anatomoradiologic study - technical considerations].

The Narrowing of the lumbar canal by spondylosis appears as a frequent factor of cauda equina compression. There is a wide range of symptomatology : common low back pain and sciatalgia; neurogenic claudication with sensitive, motor or sphincter disturbance; radicular deficit at one or several levels. Radiological measurement of the anterior-posterior diameter of the lumbar canal does not give a good evaluation of the lesion. Qualitative analysis of spondylosis must be performed by special radiological investigation : plain X ray film and tomography shows the osteophytics spurs and articular hypertrophy; sacco-radiculography (Dimer X) with tomography and flexion-extension films shows the changes on the dural sac. Three types of lesions can be distinguish on anatomical and radiological grounds which carry a special operative management : the anterior type should be treated by discectomy, at one or more level; the posterior type needs facetectomy with or without laminectomy; the mixed type must be treated by combined operative procedures. Laminectomy only does not permit the cure of lateral radicular entrapment. Our results seem much better in our series since this diagnostic and therapeutic attitude is considered.