Trial Information

Assessment of Corticosteroid Effect in the Prevention of Facial Palsy After Cerebella-pontine Angle Surgery

Facial palsy after surgical removal of cranial base tumors adherent to the nerve can partly
be explained by inflammation.

The purpose of this study was to assess the efficiency of corticosteroids to prevent facial
palsy after such surgery and to identify the patients that will have the highest benefit
from an anti-inflammatory treatment.

This study will include patients undergoing surgery for a benign tumor of the cranial base
(vestibular schwannoma). The efficiency of high dosage corticosteroids administered
intravenously during and after surgery will be evaluated on the facial nerve function in
comparison to a placebo. Pre operative and intra operative data will be collected and
analysed in order to investigate possible predictive factors of response to the treatment.

Introduction: After the surgical removal of a cerebella-pontine angle tumor (mainly
vestibular schwannoma), and despite the anatomical integrity of the facial nerve, an
immediate or delayed facial palsy may occur. This palsy may be explained by ischemia, edema,
inflammation, or a neurotmesis (ruptured axons in an intact nerve sheet). This phenomenon is
highly dependent on the size of the tumor. In our preliminary studies, we observed an
immediate facial palsy in 16% and a palsy occurring at postoperative day 8 in 23% of the
patients operated on for a vestibular schwannoma. Corticosteroids may decrease the
inflammation and the edema around the nerve and reduce the incidence of the postoperative
facial palsy. Their efficiency has already been demonstrated in idiopathic facial palsy. In
a previously published study , a single dose of dexamethasone during surgery did not
influence the facial function outcome. But the short period of the treatment do not allow
definitive conclusions.

Objectives: The aim of this study is to analyze the effect of a corticosteroid (methyl
prednisolone) administered intra- and postoperatively on the incidence of facial palsy after
surgery of cerebella-pontine angle tumors and to determine intra operative prognostic
factors for the facial function outcome.

Material and Methods: A multi center, prospective, randomized, versus placebo, and
double-blind study will be undertaken. Four-hundred patients undergoing surgery for a
cerebellopontine angle tumor will be included during 23 months. Three university departments
of otolaryngology (Hospital BEAUJON, CHU de Bordeaux, CHU de Tours) will participate. The
pre operative assessment includes a clinical examination with the assessment of the facial
function (in 6 grades according to House and BRACKMANN), an audiometry and a vestibular
testing, and a cranial MRI with the classification of tumors in 4 stages according to their
size. Patients will be randomized after information and with their consent. During surgery,
the degree of nerve stretch (4 stages), the tumor adhesion to the nerve (4 stages) and the
stimulation thresholds of the facial nerve with an electromyographic monitoring device (NIM
Response 2, XOMED MEDTRONICS, Jacksonville, FL) will be recorded. All cases of facial nerve
interruption during surgery will be excluded. In the treated group, one IV injection of
methyl prednisolone at 1 mg/kg/day will be administered intra operatively and on
postoperative days 1 and 2. The treatment will be continued on days 3 to 7 with the same
dosage orally. Subsequently, 0.5 mg/kg/day at days 8 and 8, and 0.25 mg/kg/day at days 10
and 11. The facial function will be assessed on postoperative days 1, 8 and 30 clinically.

Expected results: Considering the effect of corticosteroids in the idiopathic facial palsy
and the effect of these agents on edema and inflammation, we expect and decrease in the
incidence of immediate and delayed postoperative facial palsies. The intra operative
stimulation thresholds may indicate a subgroup of patients for which the efficiency of the
corticosteroids is higher than in the whole series.

Conclusion : The facial palsy after surgery of cerebellopontine angle tumors is the most
frequent and the most significant morbidity. Corticosteroids may decrease the incidence of
this complication.