254 Single burr hole drainage for chronic subdural haematoma NK Khadka, GR Sharma, YB Roka, P Kumar, P Bista , D Adhikari and UP Devkota National Neurosurgical Referral Centre, National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal Corresponding author: Dr Nilam Kumar Khadka, MCh Neurosurgery,National Neurosurgical Referral Centre, National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal ABSTRACT Chronic subdural haematoma is a common neurosurgical condition and surprisingly surgical treatment ranges from twist drill craniostomy to more radical membranectomy. However, the outcome is generally favourable with appropriate therapy. This retrospective study is aimed at analyzing the result of single burr hole drainage of such haematoma under local anaesthesia over a period of fifteen years. There were a total of 365 patients ranging from 6 months to 89 years with the mean age of 60 years. Recurrence of haematoma was noted in 17 (4.6%) patients and majority of them (65.0%) were managed by aspiration through the previous burr hole. Favorable outcome was noted in 98.6% patients. Those with adverse outcome were in coma preoperatively. This study suggests that single burr hole drainage under local anaesthesia is sufficient in the majority of patients and outcome was favorable even in the elderly provided they presented before lapsing into coma. Key words: Chronic subdural, haematoma, local anaesthesia, burr hole. INTRODUCTION Virchow first proposed chronic inflammation of the meninges as being the cause of a chronic subdural haematoma. 1 In 1914, Trotter suggested trauma as the etiological factor. 2 Majority of the symptomatic chronic subdural hematoma need evacuation and the surgical procedure advocated exhibits a spectrum ranging from twist drill craniostomy (TDC) to craniotomy and membranectomy. 3,4 Majority, however, favour multiple burrhole drainage. The present retrospective study analyzed the results of single burr hole drainage (BHD) under local anaesthesia without using postoperative subdural drain. MATERIALS AND METHODS This is a retrospective study of 365 patients who underwent single burr hole drainage under local anaesthesia for chronic subdural haematoma (CSDH) over a period of 15 years (July 1989 to July 2004) at a tertiary referral hospital in Nepal. The data were collected from the patients’ files, operation theatre records, hospital discharge summaries. Diagnosis was confirmed by cranial computed tomography (CT) scan and the clinical status was assessed in terms of Glasgow Coma Scale (GCS). Minimally symptomatic patients with normal GCS and without mass effect in CT were treated conservatively. Similarly, children who only required needle aspiration were excluded from the study. Patients with bilateral hematoma were considered as a single case. All were operated under local anaesthesia except children and comatose adults who were given general anaesthesia. The hematoma was drained through a single dependent burr hole and the subdural space was irrigated with normal saline using a red rubber catheter until the effluent returned clear. The head was then rotated, the cavity was filled with normal saline and the burr hole was closed without inserting a subdural drain. The patients who revealed failure of primary cerebral expansion prior to the end of wound closure or exhibited obviously thick outer membrane were put on systemic dexamethasone. Postoperatively, the patients were adequately hydrated, nursed in the flat position and allowed ambulation only after 48 hours. Prophylactic antibiotics were not used and the use of anticonvulsants was restricted only to those who had previous seizure. Outcome was assessed in terms of Glasgow Outcome Score (GOS) at three weeks and the patients in category 4 or 5 were defined as having favorable outcome. CT scan was repeated only in those who either did not recover or deteriorated. RESULTS Of the 365 patients, there were 307 (84.0%) males and 58 (16.0%) females with the mean age of 60 years (22- 96 years) (Fig-1) Characteristics of study population are given in Table-1. Important preoperative clinical findings are summarized in Table-2. There were 365 (94.0%) patients who were operated under local anesthesia. Postoperatively, dexamethasone was used in 117 (32.0%) and recurrence was observed in 17 (4.6%) patients (Table-3). The recurrences were managed by aspiration through the previous burr hole in eleven while only six patients required second burr Original Article Nepal Med Coll J 2008; 10(4): 254-257