A less invasive surgical concept for the resection of spinal meningiomas

Background. The surgical strategy for spinal meningiomas usually consists of laminectomy, initial tumour debulking, identification of the interface between tumour and spinal cord, resection of the dura including the matrix of the tumour, and duroplasty. The objective of this study was to investigate whether a less invasive surgical strategy consisting of hemilaminectomy or laminectomy, tumour removal and coagulation of the tumour matrix allows comparable surgical and cinical results to be obtained, especially without an increase of the recurrence rate as reported in the literature. Patients and methods. Between 1990 and 2005, 61 patients (11 men, 50 women) underwent surgery for spinal meningioma. All patients were treated microsurgically by a posterior approach. In 56 of the 61 patients, the above outlined - less invasive - surgical technique with tumour removal and coagulation of the tumour matrix was performed. In 5 patients, dura resection and duroplasty was additionally performed. Electrophysiological monitoring was routinely used since 1996. Recurrence was defined as new onset or worsening of symptoms and radiological confirmation of tumour growth. The pre-and post-operative clinical status was measured by the Frankel grading system. Results. Pre-operatively, 40 patients were in Frankel grade D, 13 patients in grade C, 6 patients in grade E and 1 patient each in grade A and B. Following surgery no patient presented a permanent worsening of clinical symptoms. All patients who initially presented with a Frankel grades A-C (n = 15) recovered to a better grade at the time of follow-up. Patients who presented with Frankel grade D remained in stable condition (n = 27) or recovered to a better neurological status (n = 13). Two patients experienced a temporary worsening of their symptoms, but subsequently improved to a better state than pre-operatively. Two (3.3%) complications (pseudomeningocele, wound infection) requiring surgery, were encountered. The pseudomeningocele developed in a patient who underwent durotomy. During the follow-up period of 2 months to 10 years (mean 31.3 months), 3 patients (5%) required surgery for symptomatic recurrence: 1 patient had 2 recurrences that occured 4 and 7 years after first tumour removal and matrix coagulation, 1 recurrence occurred 1 year after tumour removal that was accompanied by matrix coagulation in a patient with a diffuse anterocranial tumour extension and 1 occured 3 years after tumour removal and durotomy. Two patients showed a small recurrence on MRI during follow-up after 2 and 5 years, respectively, without any symptoms requiring surgery. Conclusions. The high rate of favourable clinical results combined with the low rate of recurrences supports our less invasive surgical concept, which does not aim for resection of the dural matrix of the spinal meningioma.