[Prognostic value of preoperative electromyography for outcome of lumbosacral radiculopathy of discal origin].

OBJECTIVES

To assess the prognostic value of preoperative electromyography (EMG) for long-term outcome in patients who undergo surgery for discal radiculalgia at the lumbar level.

PATIENTS AND

METHODS

Thirty-seven patients who underwent surgery less than 6 weeks after the EMG were selected among a pool of 384 patients suffering from discal radiculalgia at the lumbar level who had had an EMG at our hospital since 1980. Among these 37 patients, 30 were contacted by telephone for an interview on outcome after a mean 42.1 +/- 22 month follow-up.

RESULTS

Five out of 30 patients reported limitation for walking, 8/30 motor weakness, 14/30 had sensorial deficits, 12/30 had frequent or incapacitating radiculalgia, and 16/30 reported paresthesia. Patients were more satisfied with pain outcome (good or very good results in 22/30 patients (73%)) than with functional outcome (good or very good results in 20/30 patients (66%)). Preoperative EMG abnormalities (observed in 22/30 cases) were not correlated with patient age or duration of sciatica. The patients whose preoperative EMG was abnormal did not later report more paresthesia (11/20 versus 5/10) or severe radiculalgia (7/20 versus 5/10) than the others. Conversely, they complained more frequently of motor weakness (7/20 versus 1/10), but their global opinion about long-term outcome of surgery was not worse good or very good results for 15/20 patients with abnormal EMG (75%) versus 7/10 (70%) of those whose preoperative EMG was normal.

CONCLUSION

This study shows that a normal EMG does not preclude surgical cure of discal sciatica. The results of preoperative EMG do not predict the long-term outcome after surgery: indeed they are only correlated with motor weakness (7/20 versus 1/10), but not with residual pain and functional outcome.