Functional myelographic differentiation of lumbar buldging annulus from HIVD

Herniated disk and bulging annulus are the major causes of lowe back pain. It is necessary to differentiatebulging annulus from herniated disk because of their different methods of treatment. Myelography is one of theuseful diagnostic methods for disk diseases even though advanced diagnostic modalities such as CT and MRI are moreaccurate. Functional myelography is not a new technology except for two additional views, flexion and extension,are obtained with conventional myelogarpy. Differentiation between bulging annulus and herniated disk byconventional myelography is based on the extent and multiplicity of extradural deformity of the contrast filleddural sac and neural sleeve as well as the changes of nerve root. There is no previous report about differentialpoints between bulging annulus and herniated disk according to functional myelography. It is the purpose of thisstudy to find any additonal differential points on functional myelography between bulging annulus and herniateddisk over conventional myelography. Authors analysed fundtional myelographic findings of 152 cases from July 1986 to July 1987. Among them, 22 cases who had been suffered from cervical abnormality or vague lower back pain werediagnosed as normal by myelography, and 30 cases of L4-5 herniated disk and 21 cases of L4-5 bulging annulus whichhad been finally diagnsoed by operation were studied. The results were as follows. 1. In normal group, anteriorepidural space was gradually widened from the upper lumbar vertebra downward. And anterior epidural space was morewidened at the disk level in extension view than in flexion except for L5-51 level. 2. In bulging annulus group,the shape of graph of anterior epidural space in flexion state was as similar as normal. Anterior epidural spacein extension state was more widened at the buldging annulus than normal, but lesser than herniated disk. 3. Inherniated disk group, widening of anterior epidural space at the herniated disk level was persistent in bothflexion and extension views and much more exaggerated in extension. 4. In herniated disk group, anterior epiduralspace above the lesion was normal but widened at the vertebral body level just below the lesion.