Comparative study of single burr-hole craniostomy versus twist-drill craniostomy in patients with chronic subdural hematoma
Authors: Thavara Binoy , Kidangan Geo , Rajagopalawarrier Bijukrishnan 
Published: April 2019

Background: Chronic subdural hematoma (CSDH) is predominantly a disease of the elderly. On accounting its risk-to-benefit ratio, there was always controversy regarding the management of the CSDH as to which procedure is superior. Aims: The aim is to compare the clinical and radiological outcomes in patients of CSDH who have undergone single burr-hole craniostomy (BHC) versus twist-drill craniostomy (TDC). Patients and Methods: A retrospective study was conducted in patients admitted with CSDH who had undergone single BHC or TDC between January 2014 and December 2016. Patients between 18 and 90 years of age were selected. Patients with CSDH showing computed tomography (CT) scan findings of homogeneous hypodensity, homogeneous isodensity, and mixed density were selected. CT scan findings of CSDH with hyperdense gravity-dependent fluid level were also selected. Patients with CT evidence of multiple septations were excluded from the study. Recurrent CSDH, bilateral CSDH, and CSDH with secondary acute bleed were also excluded. Diagnosis was done using noncontrast CT scan. The maximum thickness of the CSDH was measured in the axial film of CT scan. The presence of midline shift (MLS) was measured as any deviation of the septum pellucidum from the midline in axial CT film. The mass effect was determined by the effacement of the sulci, sylvian fissure obscuration, or compression of lateral ventricles. The decrease in the signs and symptoms in postoperative period was considered as the postoperative clinical improvement. Improvement in the postoperative CT scan was determined by the decrease in the thickness of CSDH and absence of the MLS with decrease in the mass effect. The presence of the CSDH with mass effect and MLS was considered as the significant residue in the postoperative CT scan. Patients with significant residue underwent reoperation. Results: There were 63 patients in BHC group and 46 patients in TDC group. The mean age in BHC and TDC groups was 61.39 ± 13.21 standard deviation (SD) and 73.36 ± 10.82 SD, respectively. There were 48 (76.19%) male and 15 (23.81%) female in BHC group. There were 32 (69.57%) male and 14 (30.43%) female in TDC group. In BHC group, 41.27% were on the right side and 58.73% on the left side. In TDC group, 50% were on the right side and 50% on the left side. In BHC group, 82.54% were in the frontotemporoparietal region, 9.52% in the frontoparietal region, 6.35% in the temporoparietal region and 1.58% in the parietooccipital region. In TDC group, 86.95% were in the frontotemporoparietal region, 8.69% in the frontoparietal region, 2.17% in the temporoparietal region, and 2.17% in the parietooccipital region. There was no significant difference in duration of symptoms and history of trauma in both the groups. The symptoms of the patients in BHC versus TDC include weakness of the limbs (44.44% vs. 73.91%), headache (50.79% vs. 32.60%), altered sensorium or decreased memory (44.44% vs. 54.4%), vomiting (19.04% vs. 6.52%), speech abnormalities (15.87% vs. 19.56%), urinary incontinence (25.39% vs. 15.21%), seizure (1.58% vs. 4.34%), and diplopia (4.76% vs. 0%). The mean preoperative Glasgow Coma Scale (GCS) score in BHC versus TDC was 13.44 ± 2.23 SD versus 12.47 ± 2.95 SD limb weakness was noted in 52.38% BHC group and 82.60% TDC group. There was significantly decreased GCS score in TDC group. The number of the patients with limb weakness on affected side was significantly more in TDC group. The mean maximum thickness of the CSDH (in millimeter) in axial CT scan was 17.22 ± 4.29 SD in BHC group and 22.21 ± 4.52 SD in TDC group. The number of patients with MLS was 59 (93.65%) in BHC group and 45 (97.82%) in TDC group. There was significant difference in thickness of CSDH in both the groups. However, there was no significant difference in MLS in both the groups. There was no significant difference in prothrombin time, International Normalized Ratio, and activated partial thromboplastin time values of both the groups. There was significant difference in platelet counts of both the groups. The mean duration of procedure (in minutes) in BHC versus TDC was 79.20 ± 26.76 SD versus 27.47 ± 4.80 SD. The duration of procedure was significantly more in BHC compared to TDC. In postoperative assessment, there was no significant difference in the GCS score, power improvement, power deterioration, clinical improvement, and improvement in CT scans of both the groups. Postoperative CSDH residue requiring reoperation was significantly more in TDC group against the BHC group (13.04% vs. 1.58%). There was no significant difference in the development of acute subdural hematoma (SDH) (4.76% vs. 8.6%), reoperation rate (6.35% vs. 17.39%), complications (9.52% vs. 15.21%), and death (4.76% vs. 10.87%) in BHC group vs. TDC group. There was no significant difference in the period of hospital stay (days) in BHC (8.90 ± 5.89 SD) and TDC groups (7 ± 4.24 SD). Conclusion: The duration of procedure was significantly more in BHC than in TDC. In postoperative outcome, there was no significant difference in the GCS score, motor power improvement, motor power deterioration, overall clinical improvement, and improvement in CT scans of both the groups. Postoperative residue requiring reoperation was significantly more in TDC group. There was no significant difference in the development acute SDH, reoperation rate, complications, death, and hospital stay in both the groups. Avoiding the complications of general anesthesia and giving the equal postoperative improvement and complications of BHC, the TDC is considered as an effective alternative to the BHC in the surgical management of CSDH.