Methods

From January 2010 to December 2015, 151 large and giant vestibular schwannomas were operated in our department. Tumor diameter was between 30 and 60 mm. The most common presenting symptom was hearing loss, which was observed in 41.66% of all our patients. All patients were operated in the semi-sitting position with opening of the posterior wall of the internal auditory canal and under continuous intraoperative facial nerve function monitoring.

Results

Tumor resection was total in 126 patients. Anatomic preservation of the facial nerve was the reason for nontotal resection in 25 patients. The facial nerve was anatomically preserved in 149 patients. Two years after surgery, the facial nerve function was grade I–II House-Brackmann (H-B) score in 124 cases (82%), grade III–IV H-B score in 21 cases (14%), and grade V–VI H-B score in 06 cases (04%). The status and the improvement of postoperative facial nerve function depend on 4 factors: anatomic preservation of nerve, stimulation threshold, cystic form, and the presence of train activity.

Conclusions

The development of anesthesia techniques and microsurgery and the systematic use of intraoperative monitoring of the facial nerve have allowed us to move from a life preservation era to another era of preservation of function.

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Introduction

Acoustic neuroma is a vestibular schwannoma (VS) that develops on the vestibular nerve in the internal auditory canal (IAC) and then in the cerebellopontine angle (CPA).

Large and giant VSs1 always pose a problem in the extent of excision and preservation of the facial nerve function despite the development of microsurgery and intraoperative monitoring.

In Algeria, VSs represent 5% of all intracranial tumors operated, 80.5% of which are large or giant.

The treatment of VS has been a subject of discussion since the times of Cushing. They can be operated in 1 or 2 stages to achieve total excision with preservation of the facial nerve function and hearing if possible.2, 3, 4, 5, 6 Some surgeons perform subtotal resection followed by radiosurgery.

In our series, 151 VSs were operated on by a retrosigmoid transmeatal approach, in a semi-sitting position and with continuous intraoperative facial nerve monitoring.

Section snippets

Methods

From January 2010 to December 2015, 151 large and giant VSs were operated in our department. The mean age of patients was 48.2 years; the youngest patient was 17 years old and the oldest 78 years. There were 98 women and 43 men.

The most common presenting symptom was hearing loss, observed in 41.66% of all our patients at an average of 24 months before diagnosis. Gait instability was observed in 48.6% and tinnitus in 34.72%. Facial sensory loss or neuralgia was noted in 20%, and headache in...

Results

In our study, tumor size was more than 31 mm, with a maximum diameter of 60 mm. There were 92 patients with large tumors (31–40 mm) and 59 patients with giant VS (>40 mm) (Table 3). VS was cystic in 10 patients (6.6%).

In 2 patients, the jugular bulb was grade 2 (JB and IAC were seen concomitantly in 2 axial CT slices) (Figure 1)...

Discussion

In our study, we operated on 151 VSs with a diameter between 30 and 60 mm. All patients were operated in the semi-sitting position with opening of the posterior wall of the IAC and under continuous intraoperative facial nerve function monitoring.

In the retrosigmoid approach, the asterion is considered a good surface anatomic landmark to mark the sigmoid sinus/transverse sinus junction. The asterion was absent in 42 patients. In its absence (109 patients), the digastric point was used as a...

Conclusions

In 151 patients with VS with maximum diameter between 31 mm and 60 mm, operated on by a retrosigmoid transmeatal approach in a semi-sitting position with intraoperative facial nerve monitoring, total tumor resection was achieved in 82.8%. The facial nerve was anatomically intact in 98.7% and at 2 years after surgery, 82% of patients had an H-B score of I–II. The function of the facial nerve depended on 4 factors: anatomic preservation, stimulation threshold at the end of surgery, cystic nature...

Keywords:

Facial nerve function; Intraoperative facial nerve monitoring; Quality of resection; Vestibular schwannoma.