Facial nerve palsy – an unusual complication after evacuation of a subdural haematoma or hygroma – report of two cases

Objectives: We report a rare postoperative complication after evacuation of a subdural haematoma or hygroma.

Material and Methods: Report of two cases.

Results: Case 1: A previously healthy 15 year old boy suffered from headache and vomiting after a mild head injury. A CT scan performed 2 weeks after the trauma showed a right sided arachnoid cyst in the middle cranial fossa and a small ipsilateral hygroma. Intitially there was improvement of symptoms. But 7 weeks later acute worsening of his condition with signs of elevated intracranial pressure led to an emergency trepanation and evacuation of a space occupying subdural haematoma and subdural drainage. At first the postoperative period was uncomplicated but on the fifth day a left sided peripheral facial palsy was noted. In the postoperative MRI no changes in the course of the facial nerve were seen. The facial palsy was still marked after 8 months. Case 2: A 14 year old boy had a mild head injury without loss of consciousness. In the next weeks he had vertigo, headaches and vomiting. A CT scan 2 weeks after the trauma showed a right sided arachnoid cyst in the middle cranial fossa and bilateral hygroma, confirmed by MRI. He developed double vision and bilateral external drainage of the hygroma was performed 3 weeks after the initial trauma. Headache resolved promptly and double vision improved, but on the third postoperative day a left sided peripheral facial palsy was noted. Also in this case MRI revealed no changes in the course of the nerve. On oral steroid treatment the palsy improved, 2 months later there was only a mild asymmetry.

Conclusions: Delayed facial palsy may be a complication of acute alleviation of intracranial pressure. The facial nerve seems to be sensitive to pressure. There are few reports of facial nerve palsy in pseudotumor cerebri and cerebral venous thrombosis, delayed palsies after vestibular schwannoma resection are frequently reported. In these cases different mechanisms are discussed such as changes in microcirculation, pressure related traction of the nerve and viral reactivation.