Description of a Modified Technique (mini craniotomy-basal membranotomy) for Chronic Subdural Hematoma Surgery and Evaluation of the Contribution of Basal Membranotomy Performed as Part of This Technique to Cerebral Expansion.

Objective: To determine the effectiveness of basal membranotomy performed to ensure cerebral expansion in patients operated for chronic subdural hematoma.

Methods: Patients who were operated for unilateral chronic subdural hematoma and underwent basal membranotomy in addition to hematoma drainage were included in the first phase of the study. After the superficial membranous structures were excised, the maximum perpendicular distance between the internal tabula and the cerebral surface was measured after subdural hematoma evacuation. Subsequently, basal membranotomy was performed, the maximum perpendicular distance between the internal tabula and the cerebral surface was measured again, and the improvement in cerebral expansion was statistically calculated. The improvement of cerebral expansion in the patients who had undergone double burr hole drainage was statistically calculated in the second stage of the study.

Results: The cerebral expansion after the basal membrane excision was 41.1% in those with a 1.5- to 2-cm hematoma, 43.1% in those with a 2.1- to 3-cm hematoma, 43.5% in those with a 3.1- to 4-cm hematoma, and 45.4% in those with a hematoma thicker than 4 cm on average. No recurrence was seen during the 6-month follow-up in any patient. Double burr hole drainage revealed similar values for cerebral expansion increase with a mean value of 10%. The burr hole drainage was repeated because of recurrence in 5 patients during the 2-month follow-up.

Conclusions: The mini craniotomy-basal membranotomy technique provided statistically significantly better cerebral expansion in patients with chronic subdural hematoma when compared with the double burr hole drainage technique.