[Classification and surgical treatment of lumbosacral nerve root anomalies]

In this paper 12 cases of lumbosacral nerve-root anomalies proved on operations were reported. Two roots with a common conjoined origin entering the common intervertebral foramen separately were seen in two cases; two roots arising respectively from the lateral and ventral sides of the dural sac at the level of upper margin of the pedicle, in which one ran transversely into the foramen and another obliquely ran downward, in one case; two roots with closely adjacent origins, in which one ran transversely into the foramen at the level of upper margin of the pedicle and another obliquely ran downward, in four cases; a single root with abnormally large whereas the adjacent root with abnormally small, in five cases. We proposed a classification method for the sake of appropriate surgical program, which assorted the anomalies into three types: (I) General volume of nerve roots in the spinal canal or nerve-root canal abnormally increased, either the diameter of a single root increases or two roots entered the common. foramen; (II) The origin and course of two roots were anomalous; (III) Combination of I and II.