Key-words:
Burr hole - chronic subdural hematoma - seizures - subdural drain - subgaleal drain
Introduction
Chronic subdural hematoma (CSDH) is one of the most common neurosurgical diseases. The incidence in the general population is 5/100,000/year and is more common in aged population, i.e., 70 years and older with an incidence of 58/100,000.[[1]] Surgical treatment is mainly considered for treatment with burr hole, twist drill, and craniotomy as the preferred procedures.[[2]],[[3]] The incidence of CSDH is gradually increasing as a result of aging population and associated medical conditions like patients on hemodialysis/antiplatelets and anticoagulants. Studies have been done regarding the use of drain or no drain in these procedures.[[4]],[[5]] Few studies have compared the site of drain in CSDH. The present study is done to evaluate the role of site of drain placement in CSDH.
Materials and Methods
Patients were assigned by simple random sampling in two groups. The study was conducted from February 2016 to July 2017. A total of 70 patients were enrolled in the study and were divided in two groups (Group 1 – subgaleal drain; Group 2 – subdural drain). The study was a prospective study. Appropriate institutional ethics committee clearance and patients' consent were obtained. Patients were investigated using computed tomography scan (CT scan). Patients with CSDH having mass effect/worsening condition despite optimal conservative management were included in the study. Patients in whom intraoperative conditions warranted a craniotomy or in whom subdural drain insertion was not feasible were excluded from the study. Statistical analysis was done using Chi-square and t-test. The outcome was assessed at the end of hospital stay by modified Rankin scale (mRS). Postoperative CT scan was done after 24 h of surgery. The number of burr holes was based on surgeon's discretion. Subdural hematoma (SDH) cavity was irrigated copiously with normal saline until clear return came out.
Placement of drain
Group I – The subgaleal space was dissected widely using a blunt dissector and a subgaleal drain was placed. The end of drain was kept away from the burr hole site to avoid any accidental slippage of the tube into the subdural cavity [[Figure 1]].[[6]]{Figure 1}
Figure 1: Diagram showing placement of subgaleal drain
Group II – The subdural drain was placed in subdural space.
Romovac suction drain (Romson) was used. The drains were taken out from about 5 cm away from scalp incision. The incision was closed in two layers. The drain was connected to a soft collection bag that was kept in a dependent position. Negative pressure was not applied.
Results
Seventy patients were enrolled in the study; 35 patients each were enrolled in Group I (with subgaleal drain) and in Group II (with subdural drain).
The common clinical symptoms were headache and hemiparesis. Vomiting is seen in ten patients. Dementia and incontinence were other features. Most of the patients had Glasgow Coma Scale (GCS) 10–15. Sixty-four patients had unilateral SDH and 6 patients had bilateral SDH. Single burr hole was made in 31 patients in Group I and 27 patients in Group II. Double burr holes were made in 2 patients in Group I and 4 patients in Group II. Bilateral burr holes were made in 6 patients. The mean volume was 122.63 mL in Group I and 119.86 ml in Group II. Midline shift in Group I was 6.44 mm and 6.3 mm in Group II. Complications were seen in both the groups. Pneumocephalus was the most common complication which was seen equally in both the groups. Seizures were seen only in subdural group (five patients), while no patient in subgaleal group had seizures. Redo surgery was done in one patient in subgaleal drain group (Group I). Two patients in Group II and one patient in Group I developed intracerebral hematoma (ICH). The difference of seizures in both the groups was found to be significant. The two groups were comparable with regard to age/preoperative GCS/sex/preoperative hematoma volume/preoperative midline shift/residual hematoma/postoperative pneumocephalus [[Table 1]] and [[Table 2]].{Table 1}{Table 2}
Table 1: Comparison between two groups
Table 2: Complications in both the groups
Discussion
CSDH usually forms in the elderly population. The processes involved in the formation of CSDH are angiogenesis, fibrinolysis, and inflammation. The membrane surrounding CSDH is a source of fluid exudation and hemorrhage. Angiogenic stimuli lead to the formation of blood vessels which are fragile, while the fibrinolytic processes lead to continuous hemorrhage as they prevent clot formation.[[7]] Santarius et al. demonstrated lower recurrence rates in patients in whom drain was used as compared to no drain group at 6-month follow-up. Gazzeri et al. and Zumofen et al.[[8]],[[9]] reported a case series of extracalvarial (subperiosteal/subgaleal) drain insertion following burr-hole craniostomy (BHC). The result showed recurrence rates comparable to previously published results in literature.
Chih et al.[[10]] observed a nonsignificant increase in complications in subdural drain group.
The common clinical symptoms in CSDH are headache and hemiparesis. In our study, the incidence of headache and hemiparesis was 68% and 64%, respectively.
Bellut et al.[[11]] published the results on comparison and recurrence in subdural and subgaleal drainage. Hematoma remnant in subgaleal and subdural groups was 6.2% and 1.5%, respectively, and favored subdural drain over subgaleal drain. Guilfoyle et al.[[12]] found subdural drain to be more effective in reducing the incidence of residual or recurrent hematoma that required reoperation. In our study, we found 31.4% of patients in subgaleal drain group and 22.9%of patients in subdural drain group were having postoperative residual hematoma but was insignificant (P = 0.420). The mean residual hematomas in both the groups were also not significant.
Incidence of subdural empyema has been reported to be in a range of 0%–6%. Gazzeri et al. and Zumofen et al.[[8]],[[9]] reported very low rate of subdural empyema in association with intracranial placement of a drain. In our study, we found one patient of subdural empyema in subdural drain group.
Gazerri et al.[[8]] and Zumofen et al.[[9]] reported intracranial hematoma with the use of subdural drain. We reported two cases of ICH in subdural group.
Seizure rates of 2%–19% have been reported in CSDH patients. Oral et al.[[13]] found subgaleal drainage as relatively less invasive, safe, as the drainage tube is not in direct contact with the brain tissue and membranes of CSDH. In our study, 4.3% of patients of subdural drain group had postoperative seizures, while there were no seizures in subgaleal group.
Mean mRS was the same in both the groups at the time of discharge in our study. Kaliaperumal et al.[[14]] concluded better mRS in the subgaleal group at 6-month follow-up. Insignificant difference in mean hospital stay was observed in both the groups. Yadav et al.[[6]] reported similar results.
Conclusion
Recurrence rates after drainage of CSDH by BHC do not depend on drain position and number of burr holes. Seizure frequency and ICH formation rate are increased in patients having subdural drains. Larger studies having a larger number of patients have to be done to further investigate these findings.
