Facial Nerve Function after Surgery for Removal of Acoustic Neuroma by the Extended Middle Cranial Fossa Approach

Abstract

Postoperative facial nerve function was evaluated in 98 patients operated on by the middle cranial fossa approach or the extended middle cranial fossa approach from June 1976 to April 1985. In this series, the smaller the tumor size at the time of the initial surgery, the better the postoperative facial nerve function was. The facial nerve was preserved in 83.4% of the 79 patients who were subjected only to the initial surgery. However, total removal of the tumor along with facial nerve preservation was achieved only in 70.8%. Anatomical preservation of the facial nerve was possible in 78% of 87 patients. The postoperative functional results among patients in whom facial nerves were anatomically preserved were satisfactory (facial expression score of 75% or higher, i.e., 30 points or more out of a possible 40 points) in 70–80% of the patients with small size or intracanalicular tumors, but, in less than 50% of the patients with tumors of medium size or larger. There is a need to obtain higher rates of functional preservation as well as higher rates of satisfactory functional results. At the present stage, we must strive to achieve earlier diagnosis so that surgery can be performed while the tumor is still medium-sized or small.

Advantages of the Enlarged Middle Cranial Fossa Approach in Acoustic Neurinoma Surgery

“…Comparing the four Merent approaches (middle cranial fossa approach, translabyrinthine approach and suboccipital and retrosigmoid approach) the facial nerve was anatomically preserved in 98% out of 263 cases via our enlarged middle cranial fossa approach. Kanzaki et al (1986) was able to preserve this nerve anatomically in 83.4% operated via the same approach. As far as we know the Erlangen and Tokyo centres are the only ENT departments in the world removing even large acoustic neurinomas via the enlarged middle cranial fossa approach.…”

“…The chance of preservation of the facial nerve function drops considerably for larger tumours of about 2.0 to 3.0 cm in size (House & Luetje 1979;Rand 1982;Glassock et al 1986;Kanzaki et al 1986;Fisch 1988;. This implicates the indication to remove acoustic neurinomas at an early stage with an approach that is believed to preserve facial nerve function.…”

Hypoglossal-facial nerve anastomosis: assessment of clinical results and patient benefit for facial nerve palsy following acoustic neuroma excision

“…This may be due to infiltration of the facial nerve by the acoustic neuroma, especially if the tumour is large 12,13 . Facial nerve palsy following acoustic neuroma surgery occurs more often with larger tumour resections 11,14 . In our unit we preserved facial nerve function in 108/109 (99%) small (< 2.5 cm) acoustic neuroma resections compared with 53/63 (84%) medium sized tumours (2.5–4 cm) and 17/23 (74%) large tumours (> 4 cm).…”

Distance From Acoustic Neuroma to Fundus and a Postoperative Facial Palsy

“…Postoperative facial palsy is one of the serious sequelae in AN surgery, and its prognostic factors have been variously reported. 2–4,14–17 Tumor size has been thought to be the most important factor. 2,4,5 The facial nerve can tolerate a large degree of stretching, compression or distortion, which is caused by tumor, without apparent facial palsy.…”

“… 1 It is generally said that the patient with a small tumor has less facial nerve damage after the surgery. 2–4 Because of superior ability to achieve hearing preservation, the middle cranial fossa approach (middle fossa approach [MFA]) has been advocated for removal of the AN. This approach is mainly applied for relatively small tumors, and satisfactory facial nerve function after the MFA has been also reported.…”