Membranectomy in organized chronic subdural hematomas: indications and technical notes

Background: The aim of the present study is to present our operative method of removing organized CSDHs and to structure the criteria for choosing this approach as first treatment. Methods: Between 1991 and 1999 at our Institution, 14 consecutive patients with organized CSDHs required 16 craniotomies with membranectomy. They represent 5.8% of all patients (243) treated for CSDHs in the same period. All the patients had preoperative contrast-enhanced CT, and 9 patients also had contrast MRI. Results: Initially, 9 patients underwent one burr hole or twist-drill hole. Of these 9 patients, 3 were treated at the same surgery with craniotomy and membranectomy as second treatment, 3 underwent a second burr hole and then membranectomy at the same surgery, and 3 patients underwent a second burr hole 3, 4, and 21 days after the first one and then membranectomy. Five patients underwent immediate craniotomy and membranectomy. There were no morbidity or mortality associated with this procedure. All patients had a full recovery without recurrence. Conclusions: Contrast-enhanced MRI has greatly improved opportunities for discovering neomembrane before surgical intervention. We believe that MRI detection of thick and extensive membranes or solid clot with mass effect makes an immediate craniotomy to remove CSDH necessary.