gms | German Medical Science

Objective: Lumbar spinal stenosis has an increasing incidence in elderly patients. Diagnostic measures must be focused to clearly identify the clinically relevant stenotic levels. Especially in elderly patients with increased comorbidities the extent of the surgery has to be tailored as precisely as possible in order to optimize the results. We investigated MRT, functional myelography and post-myelography CT regarding their precision in identifying lumbar spinal stenosis.

Method: We examined patients with clinically relevant lumbar spinal stenosis. On each patient a MRI, a functional myelography as well as a post myelography CT were performed in order to identify the stenotic levels. The saggital diameters of the spinal canal were measured at all levels L1-S1 on each patient. The different methods were compared regarding their sensitivity and specifity and positive predictive value.

Results: Fifty consecutive patients (21 female, 29 male, mean age 71 years, age range 45-86 years) who were operated because of lumbar spinal stenosis were investigated. We examined 499 spinal levels by MRT, 498 levels by myelography and 481 levels by post myelography CT. Myelography revealed a sensitivity of 0.99, a specifity of 0.79 and a positive predictive value of 0,45. MRT exhibited a sensitivity of 0.93, specifity of 0.74 and positive predictive value of 0,39. Post myelography CT showed a sensitivity of 0.96, a specifity of 0.75 and a positive predictive value of 0,41.

Conclusions: Functional myelography has the advantage of axial loading during the examination. In patients with multiple stenotic levels the main levels can be identified more clearly without omitting other relevant levels. Therefore, this technique still seems to be of advantage in planning spinal surgery especially in the elderly.