Risk factor for unsatisfactory outcome after lumbar foraminal and far lateral microdecompression

Study Design. A retrospective study of consecutive patients who underwent microdecompression for far lateral disc or foraminal stenosis. Objectives. To evaluate the risk factors for unsatisfactory outcome. Summary of Background Data. There has been no detailed analysis of postoperative radicular pain, although it is not infrequent following foraminal and far lateral microdecompression. Methods. A total of 184 patients, who were followed up for more than 2 years, were reviewed. Microdecompression was performed through lateral intermuscular approach. In cases of double herniation (combination of intracanalicular disc at the same level), additional intracanalicular decompression was simultaneously performed. The unsatisfactory outcomes included persistent or recurrent leg pain, based on the Japanese Orthopedic Association leg pain score, and revision surgery at the same level. The potential risk factors, including gender, age, symptom period, preoperative radiologic and intraoperative findings, were determined. Results. The average follow-up period was 38.4 months, with a maximum 70 months. Forty of the 184 patients (21.7%) had persistent or recurrent leg pain, with nine requiring revision surgeries. The statistically significant risk factor for unfavorable outcomes was double herniation, with odds ratio of 2.89 (P = 0.004). Conclusion. Facet preserving microdecompression is an effective method for foraminal and far lateral root compression. However, in cases of double herniation, total facetectomy is preferable.