FAR LATERAL DISC HERNIATIONS TREATED BY MICROSCOPIC FRAGMENT EXCISION - TECHNIQUES AND RESULTS

Study Design. This was a retrospective review of a consecutive series of patients who underwent excision of far lateral disc herniations by a paraspinal, muscle-splitting incision that spares the facet. Objective. The authors describe the surgical technique in detail and review the results of surgical treatment. Summary of Background Data. As the lumbar nerve roots exit the intervertebral foramen, they once again lie in juxtaposition to an intervertebral disc and are susceptible to compression with subsequent radiculopathy. Radiculopathy caused by disc herniations in this area is less common, and the anatomy is less familiar to spinal surgeons than that of paramedian disc herniations. The involved root can be approached by a transfacetal approach or by a muscle-splitting approach that spares the facet. Methods. Thirty-one consecutive patients had undergone the muscle-splitting approach to far-lateral disc herniations. Twenty-five (80.6%) of these patients were available for evaluation at a minimum of 2 years after surgery. Evaluation consisted of history, pain questionnaires, visual analogue scales, physical examination, and plain radiographs. Results. Twelve patients (48%) had excellent results, eight (32%) had good, and five (20%) had either fair or poor results. Low back pain and dysesthesias were causes of unsatisfactory results. No radiographic sign of instability developed postoperatively. Conclusion. The anatomy of the nerve root lateral to the pedicle and our technique for microscopic excision of herniated disc fragments lateral to the facet are described. Our overall results were encouraging. The described microscopic technique will hopefully minimize dysesthetic pain that appears to be the result of the manipulation of the dorsal root ganglion.