Intracranial subdural haematomas: a rare but disabling complication of spinal anaesthesia

Background: Intracranial subdural haematomas (SDH) after subarachnoid blocks (SAB) are a very rare complication, which results in persistence of post procedure headaches and neurologic deterioration. Acute change in CSF pressure dynamics resulting in tears of bridging veins has been implicated. Aim: To highlight our findings of intracranial SDH following SAB in the period 2018 to 2023 in Port Harcourt. Methods: Patients who had persistent headaches with neurologic deterioration after SAB had brain imaging done. Those with SDH were recruited. They had burr hole evacuation of haematomas. Results: Twelve patients (11 females), with a mean age of 41.0±9.8 years were recruited. Ten patients had SAB, and 2 had Combined spinal epidural (CSE) anaesthesia. SAB was done with size 22G spinal needle in 3 patients and 24G in 5 patients. Confusion, headaches, alteration in consciousness, and paresis occurred in 66.7%, 100%, 75% and 83.3% of patients respectively. 16.7% patients were Mark-Walder grade IV, 8.3% grade III, 41.7% grade II, and 33.3% with grade I. 41.7% patients had bilateral SDH and 33.3% had left SDH. Chronic SDH was noted in 41.7% patients and others had subacute SDH. Mean interval between onset of symptoms to surgery was 6.3±7.3 days. Clinical recoveries were noted in all patients with postoperative modified Rankin Scale (mRS) scores at 14 days of 0. Conclusion: Intracranial subdural haematomas may be rare but are a major cause of headaches with neurologic deteriorations after subarachnoid blocks. A high index of suspicion and prompt management results in good outcomes.