Consistency of lumbar discograms of the same disc obtained twice at a 2-week interval: influence of needle tip position

: Although numerous papers have emphasized the importance of accurate needle positioning in lumbar discography, no concrete evidence is available to support this contention, and no study has evaluated the image consistency of discography as influenced by this factor. By observing the consistency of two images in relation to needle tip position we aimed to clarify the importance of needle positioning in discography. One hundred and ninety-two patients (324 discs) receiving steroid intradiscal therapy in whom discography of the same disc was performed twice at a 2-week interval and in whom the needle tip position was within the acceptable range (as defined by us) were studied. The patients were divided into two groups: in group G, in whom the needle tip was within a limited range on both discograms, and group P, in whom the needle tip was in this range on only one discogram. Image consistency was compared roentgenographically in the two groups. The consistent image rate for the total number of discs was 48.5%, being significantly higher in group G (53.2%) than in group P (39.0%). The rates were lower in the nucleus pulposus and the posterior portion of the disc than in the other disc areas, but were significantly higher in group G (85. 4% and 75.0%, respectively, for these two areas). The necessity for accurate needle tip positioning was proved roentgenographically.