gms | German Medical Science

Objective: Visual impairment is the leading symptom of anterior or middle skull base tumors affecting the optic nerve (ON) within the optic canal (OC). Intradural decompressive surgery of the ON remains the crucial step to prevent visual detoriation. Hence, we evaluated the operative procedure, histological entity of tumors, and the visual outcome in patients who underwent unroofing of the OC in our institution.

Method: Consecutive patients with tumorous affection of the ON within the OC operated between 01/2011 - 09/2014 were retrospectively analysed. Their charts were reviewed with special respect to presenting symptoms, operative procedure and complications, as well as histological entity. OC unroofing was performed by using a high speed drill with a diamond burr under continuous irrigation exposing the optic dural sheets.The dura was incised longitudinally using a sickle microknife. Ophthalmologic examination consisted of testing patient's visual acuity and visual field before and after surgery.

Results: The study group comprised 46 patients (16 male, 30 female) with a median age of 53,3 years (range 3 - 88 years). Most common presenting signs were visual impairment (87%), followed by headache (33%) and trigeminal sensibility disorder (9%). 41 (90%) patients were operated via a standard pterional craniotomy, comprising 5 cases of surgical extension by orbitotomy. Fronto-temporal (2, 4%), fronto-temporo-orbito-zygomatic (2, 4%), and subfrontal (1, 2%) craniotomy were infrequently performed. Postoperative complications were rare with 1 (2%) case of epidural haematoma and 1 (2%) case of wound infection. There was no intraoperative complication. Histology revealed 35 meningeomas WHO °I (76%), 4 cases of granulation tissue (9%), 3 pituitary adenomas (7%), 1 pilocytic astrocytoma WHO °I (2%), 1 salivary gland carcinoma (2%), 1 histiocytosis (2%) and 1 arachnoid cyst (2%). Improvement or preservation of visual acuity and visual field were achieved in 94% and 97%, respectively. Visual deterioration and visual field confinement after surgery was documented in only 6% and 3% respectively.

Conclusions: The pterional approach is the standard route of operation in our department, facilitating a safe method of combined surgical confirmation of diagnosis and intradural decompression of the OC. Improvement and preservation of visual acuity and visual field is achieved in a high number, with no intraoperative and a low frequency of postoperative complications, respectively.