Retrospective analysis of surgical outcomes of chronic subdural hematomas

Chronic subdural hematoma is one of the most common types of intracranial hemorrhage in brain surgery practice. A common form of behavior for the surgical technique to be applied in the treatment of chronic subdural hematoma has not yet been accepted. Frequently, twists-drill craniostomy, burr-hole craniostomy and craniotomy surgical techniques are applied.1 Burr-hole craniostomy, the discharge of hematoma by opening 1 or 2 burr-holes to the side of the hematoma, has been the most popular surgical technique in the world.1 The aim of all surgical techniques is to provide decompression of cerebral hemispheres and to prevent recurrence by minimal morbidity and mortality. After the evacuation of chronic subdural hematoma with burr-hole in the last 20 years, the idea of drain insertion to the cavity for reducing the recurrence was accepted. 87 patients who underwent surgery with the diagnosis of chronic subdural hematoma between 2007-2018 in Istanbul University Faculty of Medicine were examined retrospectively by reaching patient records from neurosurgery archive of our faculty. Patients were investigated according to gender, age, trauma history, comorbidities, anticoagulant or antiaggregant uses, pre-and postoperative Glasgow Outcome Scales, computerized tomography of the hematoma (low density, isodensity, mixed density), whether the hematoma is unilateral or bilateral, the type of membrane (single layer, double layer or multiple layers), preoperative and postoperative midline shift, burr-hole numbers opened in surgery, the insertion of the drain or not and the type of drain used. Patients were divided into 3 groups including subgaleal drain group, subdural drain group and the drain-free group. In radiology unit, in order to see the drain location and assess possible complications, the control computed tomography was taken. After the operation, control of cranial computed tomography was performed in 3 months and 6 months. Recurrence was defined as the increase of hematoma volume in control imaging and the continuation of the patient's symptoms. There was a recurrence rate of 26.9% in the non-drain group, while in the subdural drain inserted grup it was 20% and 13.3% recurrence was observed in the Subgaleal area. R A single membrane subdural hematoma was observed in 8 (40%) of the patients with exuration, a subdural hematoma with double membrane in 11 (55%), and a subdural hematoma with multiple membranes (5%) in 1. Compared to membrane types, patients who underwent surgery that have double membrane subdural hematoma, were found to have more recurrence than others. (p = 0,043) The result was statistically significant. In our study, 6 (30%) of the 20 patients with recurrence were observed to use antiaggregant in the preoperative period. In 1 (5%) patients, anticoagulant use was present in the preoperative period, and recurrence was observed. The results were not statistically significant. (p = 0,581 patients receiving antiaggregant therapy, p = 0,640 patients receiving anticoagulant treatment) A single burr-hole was opened in 1 patient (5%) from 20 patients with recurrence, 15 patients (75%) were opened 2 burr-holes, 4 (20%) patients were operated by opening 3 or more burr-hole. The number of burr-hole didn't effect the recurrence between the groups. The result was statistically significant. (p = 0,177) As a result, patients that diagnosed with chronic subdural hematoma, drainage to the cavity reduces recurrence and the drain insertion to subgaleal area is preferable due to less mortality and recurrence compared to the subdural drain. When radiographic images of pre-operative cases were examined, the data obtained in the literature and this study can give an idea about the recurrence by evaluating the membrane types and hematoma density about recurrence. With large populations and the number of patients with more drain, it is necessary to support this outcome and to obtain stronger evidence with randomized prospective studies and compare it to existing results.