Significance of sciatic scoliotic list in operated patients with lumbar disc herniation

Abstract

Study design: The authors retrospectively reviewed the relation between the location of disc herniation and pre- and postoperative changes in sciatic scoliotic list in 40 patients with surgically confirmed lumbar disc herniation who had sciatic scoliotic list with postoperative recovery. Clinical factors associated with scoliosis also were included.

Objectives: To evaluate the significance and pathomechanism of sciatic scoliotic list.

Summary of background data: The proposed causes of lumbar sciatic scoliosis mainly imply an alleviation of nerve root irritation in relation to the anatomic location of disc herniation relative to the nerve root.

Methods: The pre- and postoperative serial Cobb angle between L1 and L5 in anteroposterior lumbar radiographs in the standing position were measured. The relation between the convex side of scoliosis and clinical parameters in terms of the side of symptoms, age, gender, duration of low back pain or leg pain, the angle of a positive straight leg raising test, and the time required for recovery of sciatic scoliosis were investigated. In addition, magnetic resonance imaging also was performed in five recent cases from 40 patients.

Results: The average Cobb angle decreased from 10.7 degrees to 2.7 degrees within an average of 7.5 months after surgery. The preoperative Cobb angle of patients with disc herniation medial to the nerve root was significantly higher than that just beneath or lateral to the nerve root. Thirty-two of 40 patients (80.0%) had a lumbar disc herniation at the convex side of scoliosis, irrespective of the transverse location of the herniation. The time required for scoliosis disappearance in disc herniation located lateral to the nerve root tended to be longer than that for other types of disc herniation. Magnetic resonance imaging through the paramedian planes showed enlargement of the intervertebral foramen at the convex side of scoliosis, compared with that at the concave side in five recent cases from the current study.

Conclusion: These results suggest that sciatic scoliotic list is not a predictive factor of the anatomic location of disc herniation; rather, it is only suggestive of the side of disc herniation. The location of disc herniation may aide in the preoperative estimation of the recovery of the scoliosis.