[Feasibility of endoscopic surgery by paravertebral approach in far lateral lumbar disc herniation]

To evaluate the feasibility of endoscopic paravertebral approach surgery in the far lateral lumbar disc herniation.

Fifty sets of integral lumbar vertebral specimens were selected, and the anatomical data of lumbar intervertebral foramina and its adjacent structures were measured. Twenty specimens are randomly divided into a traditional group and an endoscopic group, then the traditional and endoscopic operations by paravertebral approach were used to dissect every strata of soft tissues in order to expose the intervertebral foramen. At last,the relationship between the intervertebral foramen and its adjacent structures was observed, and the 2 procedures were compared.

The sagittal diameter of lumbar intervertebral foramina became shorter from the top to bottom,while the diameter of cross section of relative nerve roots became longer. The depth of the line which connected the middle point of the 2 adjacent transverse process roots and the anterior branch of lumber nerve root in L1,L3 and L5 was (1.03+/-0.30), (1.71+/-0.29), and (1.99+/-0.34) mm respectively, with the increasing tendency; the depth of L3 to L5 was mostly less than 2 cm. The distance of the middle points of the 2 adjacent transverse process roots from L1 to L5 was long enough, but the distance between L5 and S1 was only (10.14+/-1.71) mm. The surgery by paravertebral approach had a relative safe operation area,which was similar to a triangle.

The technique of endoscopic surgery by paravertebral approach is feasible in the treatment of far lateral lumbar disc herniation. However, it is difficult to perform this surgery in the treatment of L5/S1 far lateral lumbar disc herniation, which is often conducted with endoscopy, after 18 to approximately 20 mm of the partial sacrum is eliminated by conventional method.