The surgical treatment of complete block in lumbar metrizamide myelography.

Twenty-seven patients with complete block in lumbar metrizamide myelography were analysed to ascertain the mechanism of block and the difference of surgical results btween anterior and posterior approaches. The cases of tumor were excluded. The mechanism of complete block was thought to be the combination of various factors including redundant nerve root, adhesion, fibrosis, huge central disc hernia, sequestrated disc hernia, hypertrophy of facets, lamina and yellow ligament dagenanation epnndylnliathnino, and dynanin instability.The results of anterior approach are better than those of posterior approach, and the results of multiple operated back are worse than that of posterior approach. Even though complete block is present in myelography, the anterior approach is recomended, if main lesion consists of anterior portion (disc, displacement, instability) and the case is younger than fifty years old and lesions are less than two intervertebral levels.