OBJECTIVESTo suggest the clinical classification of the far-lateral lumbar disc herniation and offer the considerations for clinical choice of different surgical procedures.

METHODSAccording to the locations of the herniated disc and relevant clinical symptoms, the far-lateral lumbar disc herniation was divided into three types: Type I: posterolateral and foraminal herniation(double herniations); Type II: foraminal disc herniation and Type III: extraforaminal herniation. From January 2002 to January 2007, 38 patients with far lateral lumbar disc herniation underwent surgery in the institute. The surgical options were decided by means of the classification. The surgical procedures included (1) discectomy by inter-TP (transverse process) approach, (2) discectomy with partial facetectomy and (3) discectomy with facetectomy and PLIF (posterior lumbar interbody fusion). Among the 38 patients, there were 25 males and 13 females. The mean age was 58.4 years old. The herniated discs located at L(3-4) in 17, L(4-5) in 13, and 8 cases at L(5)S(1). Twenty-three patients were simple disc herniation, 15 cases with concomitant lumbar spinal stenosis. The symptoms and signs of exiting root compression at herniated disc level were presented in all patients and passing root compression presented in 7 Type I cases as well; while intermittent claudication being presented in 15 and low back pain in 21 patients. The VAS (visual analog pain scale) of radicular leg pain was taken before and after the operation. The postoperative outcomes were evaluated through the MacNab's method in all the patients.

RESULTSBy using the new classification system, the 38 patient were divided into Type I 10 cases, Type II 19 cases and Type III 9 cases. The adopted surgeries included discectomy by intertransverse approach in 5, discectomy with partial facetectomy in 7, and discectomy with facetectomy and PLIF in the rest 26 cases. The mean follow-up period was ranging from 6 months to 4 years and 10 months, average 2 years and 11 months. The mean VAS scores of radicular pain was 7.4 preoperatively, 2.7 at 2 weeks after the operation and 3.1 at final follow-up. The final clinical outcomes by MacNab's method were as follow: excellent results in 20 cases, good in 12, fair in 5 and poor in 1 case. The overall improvement ratio was 84.2%. The postoperative complications included superficial wound infection in 1 case, insufficient decompression in 1 case and leakage of cerebrospinal fluid in 1 case respectively. No breakage and loosening of internal fixation were detected.

CONCLUSIONSA new clinical classification of far lateral lumbar disc herniation was suggested, which is significant to understanding the relevant pathology and choosing the surgical procedures.