EVALUATION OF VARIED SURGICAL APPROACHES USED IN THE MANAGEMENT OF 170 FAR-LATERAL LUMBAR DISC HERNIATIONS - INDICATIONS AND RESULTS

This study was undertaken to determine and compare indications and relative benefits of various surgical approaches in 170 patients (average age 55 years) with far-lateral herniated lumbar discs, identified by magnetic resonance (MR) imaging and computerized tomography (CT) and operated on between 1984 and 1994. Essentially three surgical procedures were performed:: complete facetectomy in 73 patients, laminotomy with medial facetectomy in 39 patients, and intertransverse discectomy (also known as ITT) in 58 patients. Follow-up periods averaged 5 years (range 0.5-10 years). Outcomes were scored as excellent (no deficit), good (mild radiculopathy), fair (moderate radiculopathy), and poor (unchanged or worse). Overall, excellent and good results were achieved in 73 and 51 patients, respectively, and fair and poor results in 26 and 20, respectively. There was little difference among the results encountered for the three major surgical groups: 79% of the intertransverse (ITT) group had good-to-excellent outcomes, as compared with 70% of the facetectomy group, and 68% of the group who underwent at minimum laminotomy, and additional hemilaminectomy or laminectomy with medial facetectomy. Results were the same for the 121 patients followed for more than 2 years and for the 49 patients studied for under 2 years. In the management of far-lateral discs, total facetectomy provides the best exposure, but increases the risk of instability. Laminotomy and medial facetectomy uncover the lateral and subarticular recess and preserve stability, but visualization of the far-lateral compartment is often inadequate. The intertransverse approach offers extensive far-lateral but not medial intraforaminal exposure, while also preserving stability. Full facetectomy, laminotomy with medial facetectomy, and the intertransverse approaches yielded nearly comparable outcomes in far-lateral disc surgery. Only the full facetectomy exposes the entire course of the nerve root both medially and laterally, whereas the intertransverse procedure provides direct exposure of the far-lateral compartment alone. It is important to select the correct approach or combination of approaches to address attendant complicating factors such as spinal stenosis, spondyloarthrosis, and degenerative spondylolisthesis identified on CT and MR studies.