Morphology of spinal canal and dural sac before and after operation of lumbar stenosis in digital computer tomography

Introduction. Stenosis or spinal canal narrowing is a term used for description of structural narrowing
of spinal canal diameter.
Aims of the study were to: 1. Undertake prospective studies in order to evaluate with the use of
digital computer tomography dimensions of spinal canal. 2. Examine with the use of digital CT
a value of operative decompression of neural structures. 3. Find mathematical relationships between
dural sac surface area and narrowed spinal canal before and after operation.
Material and methods. Examined group consisted of 176 patients (83 men and 93 women). Authors
examined and evaluated 528 levels that were compared to control group (42 persons). Examinations
were made with the use digital CT. Detailed analysis was conducted on 48 patients from study group
treated operatively. This group had a complete clinical and radiological documentation.
Results. Statistically significant differences were found
– on L4 and L5 between control group (N) and the group before and after the operation.
• L4: Norm – 297,7mm2; before operation – 275,1 mm2; after operation – 315,8 mm2
• L5: Norm – 386,5 mm2; before operation – 305,7 mm2; after operation – 383,8 mm2
– Rate defining dural sac surface area to spinal canal surface area on L4 and L5 level between
control group (N) and the group before and after the operation.
• L4: Norm – 69,84%; before operation – 51,44%; after operation – 67,01%
• L5: Norm – 70,31%; before operation – 61,04%; after operation – 69,79%
Conclusions. 1. Surface area of spinal canal after surgical decompression was comparable to control
group spinal canal surface area. 2. Rate defining dural sac surface area to spinal canal surface
area on L4 and L5 level between control group (N) and the group before and after the operation
was comparable to the rate of normal spine.