This is a study on the results of fifty consecutive patients who underwent endoscopic removal of herniated lumbar disc by interlaminar extra-dural approach. The indication for surgery was unrelenting, single level, unilateral sciatic pain not relieved by conservative treatment, with supportive evidence of disc herniation in MRI. Surgery was carried out in the lateral position. After localizing the disc space by X-ray, two 5 mm portals were made, one for an arthroscope and the other for working instruments. The spinal canal was entered through the inter-laminar route and under direct vision the herniated lumbar disc was removed.

The duration of study is from February 1998 to July 1999 with an average follow-up of 14.58 months. There were 31 herniated, 9 extruded and 10 sequestrated discs. All patients were mobilized the same day and 42 were discharged the next day. There were two patients who suffered partial but permanent nerve root damage, 4 had post-operative headache and one developed transient extra-pyramidal symptoms. Modified McNab criteria were applied to study the results by an independent observer.

40 patients (80%) had a very good outcome (i.e. fully functional with occasional discomfort); 5 patients were considered to have a good outcome (i.e. normal function with some restriction to strenuous activity); 2 patients who had partial nerve root damage were considered as fair results though their final outcome was good. 3 patients suffered recurrent disc herniation and were operated by open surgery. These were classified as failures. We conclude that this technique is a minimally invasive procedure with results comparable to conventional disc surgery. The advantages to the surgeon are the excellent illumination, magnification and visualization. The advantages to the patient are minimal surgical trauma and speedy recovery.