- Dysgeusia is a potential complication of endoscopic, endonasal transcribriform approaches to resection of olfactory groove meningiomas
- Patients with olfactory groove meningiomas (OGMs) should have their senses of smell and taste formally tested before any type of surgery
- Patients considering EETA for OGM resection should be counseled about the risk of postoperative dysgeusia, as well as potential olfactory complications
Olfactory groove meningiomas (OGM), which form along the anterior skull base, usually are benign tumors and can be removed surgically. Endoscopic endonasal transcribriform approaches (EETA) to surgery provide direct access inferiorly to the tumor with a panoramic view. EETAs are also less invasive, do not require brain retraction, allow early identification and coagulation of the tumor blood supply, and facilitate removal of any hyperostotic bone en route to the OGM.
After resection of OGMs, anosmia is common and other olfactory symptoms including hyposmia, dysosmia and phantosmia can occur, and there is no established therapy for those complications. Until now, abnormal taste perception was not known to be associated with any type of anterior fossa pathology. In the Journal of Neurological Surgery, Andrew S. Venteicher, MD, PhD, a resident at Mass General, William T. Curry, MD, co-director of Mass General Neuroscience, and colleagues report what appear to be the first two published cases of dysgeusia after EETA for resection of OGM.
The first case concerns a 35-year-old woman who presented with headache and hyposmia. She had a seven-year history of intermittent dysphagia. Imaging revealed a 3.2 cm OGM, and she underwent an EETA in which the entire cribriform plate was removed. Her immediate postoperative period was uneventful except for expected anosmia.
Four months after surgery, the patient reported a persistent, noxious, metallic or bleach-like taste in her mouth that was exacerbated by drinking. She could distinguish sweet, salty, bitter and sour tastes. The anosmia persisted. A two-week course of amoxicillin–clavulanate, prescribed to treat potential subacute infection, had no effect on the taste disturbance. At seven months, the patient still had anosmia and said the dysgeusia had changed to a persistent “moldy or dirty” sensation in her mouth.
Ten months after surgery, the patient exhibited left-sided facial weakness and received a seven-day course of valacyclovir and prednisone for possible Bell’s palsy. The facial weakness eventually resolved but the dysgeusia persisted.
The other patient, a 40-year-old woman, had a previous history of left optic nerve sheath meningioma treated with radiation therapy. She subsequently presented with frontal headaches, and imaging detected a 1.1 cm OGM. She underwent an EETA in which the inferior portions of the superior turbinates were resected, sphenoidotomies were created and a left nasoseptal flap was harvested.
Before surgery, this patient’s sense of smell was intact. Six weeks afterward, she reported constant sensations of an unpleasant sweet-smelling phantosmia and “foul” distorted taste of food. Her neurological examination was otherwise normal, and endonasal examination showed a healthy nasal graft and a healed graft harvest site. The patient’s phantosmia and dysgeusia persisted at her most recent appointment, five months postoperatively.
The authors recommend that patients with OGMs should have their senses of smell and taste formally tested before surgery. Those with olfactory loss preoperatively seldom recover a sense of smell after surgery. On the other hand, if olfaction is intact before surgery, a craniotomy approach offers a reasonable chance of preserving it.
All patients contemplating EETA should be counseled about the risk of postoperative phantosmia and dysgeusia, the authors add.
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