Evaluation of hemilaminectomy use in microsurgical resection of intradural extramedullary tumors.

The aim of this study was to investigate the microsurgical techniques of hemilaminectomy, used in the excision of intradural extramedullary (IDEM) tumors, and to illustrate its clinical effects. Clinical data obtained from 16 patients (seven males, nine females) with IDEM tumors, which were treated at the China-Japan Union Hospital between January 2009 and December 2011, were retrospectively analyzed. The mean age of patients was 49 years, ranging from 34-72 years. The IDEM tumors were located cervically in three patients, thoracically in four patients and at the thoracico-lumbar level in nine patients. Fourteen patients underwent hemilaminectomy, while two patients were treated with laminectomy during surgery. The clinical effect of hemilaminectomy was evaluated based on Frankel grade. The mean bleeding volume was 300 ml (range, 150-500 ml) and the mean duration of surgery was 140 min (range, 90-200 min). The maximum and minimum tumor volumes were 4×1.5×1.5 cm and 1.5×1.0×1.0 cm, respectively. Neurinoma was evident in 11 patients, meningioma in four cases and neurofibroma in one case. Three cases improved from Frankel grade B to C, five cases improved from grade C to D and seven cases improved from grade D to grade E. All patients were followed up for a period of 6-40 months, with a mean follow-up time of 23.7 months. None of the patients exhibited tumor recurrence or spinal instability. The mean bleeding volume of patients that underwent hemilaminectomy and laminectomy was 275 and 475 ml, respectively. The advantages of hemilaminectomy are minor invasion, less bleeding and retention of spinal stability. In general, hemilaminectomy for the excision of IDEM tumors has a satisfactory outcome.