Delayed facial nerve palsy after vestibular schwannoma surgery
Background: Facial nerve dysfunction may occur immediately after vestibular schwanoma surgery. Electromyographyc monitoring of motor cranial nerves during cerebellopontine angle surgery has become an essential tool. Although delayed onset of facial nerve dysfunction hours to months following vestibular schwanoma surgery are rare. Case description: We describe the case of a 70-years-old male who was admitted with a left side tinnitus and hearing loss of the last 3 years. Magnetic resonance imaging (MRI) T1-weighted demonstrated an isointensity lesion, 30mm in diameter, at the left cerebello-pontine angle with a small portion in the internal auditory canal. The patient was surgically treated by means of a standart suboccipital retrosigmoid approach. The facial nerve was monitored by continuously during surgery. Surgical removal was macroscopically complete. The facial nerve was well-preserved during surgery and showed at the end of the procedure normal electromyographic activity. The patient did well postoperatively and was discharged at the 4th postoperative day and facial function was normal (House-Brackmann grade I). On the 10th postoperative day he notices difficult closing his left eye that progressed to complete facial nerve palsy (House-Brackmann grade III). Steroid therapy was performed for five days associated with physical therapy. One month later his facial nerve function had completely recovered. After six months, the patient remains asymptomatic and neurologically intact. MRI obtained at the 16th postoperative day showed intense enhancement of the intracranial facial nerve segment and also demonstrated no residual tumor. Immunological study at the time of onset showed herpes simplex virus antibody titer normal as well as those for herpes zoster virus. Conclusions: Delayed facial nerve palsy remains an under reported and consequently not very known phenomenon in the neurosurgical practice and literature. Because of the 2009favorable rate of recovery, patients should be reassured in the interim and should not undergo any corrective surgical procedures to improve facial nerve function. Delayed facial nerve palsy is uncommon after vestibular schwannoma surgery. Excellent recovery of facial nerve function to the original postoperative status nearly always occurs in those circumstances.