PATTERNS OF CHRONIC ADHESIVE ARACHNOIDITIS FOLLOWING MYODIL MYELOGRAPHY - THE SIGNIFICANCE OF SPINAL-CANAL STENOSIS AND PREVIOUS SURGERY

109 patients who had undergone Myodil myelography on at least one occa sion were identified. The patterns of lumbar nerve root distribution i n this group were examined using magnetic resonance imaging. The relat ionship between these patterns and the presence of spinal stenosis or previous surgery was investigated. Chronic adhesive arachnoiditic nerv e root patterns were seen in 68 patients and were classified into thre e groups according to Delemarter et al. Central clumping of nerve root s (type 1) and complete opacification of the thecal sac (type 3), exte nding over at least one vertebral level, were significantly related to spinal stenosis at an adjacent level (p<0.0001). Peripheral adhesion of nerve roots to the theca (type 2) was significantly related to prev ious surgery at the level of abnormality (p<0.00005). Only a single ca se of arachnoiditic nerve root patterns was seen in the absence of ste nosis or previous surgery. We conclude that chronic adhesive arachnoid itis is significantly related to previous Myodil myelography in the pr esence of spinal stenosis or previous surgery but that Myodil alone ra rely produces these changes.