Bell's palsy is an acute paralysis of one side of the face of unknown aetiology. Bell's palsy should only be used as a diagnosis in the absence of all other pathology. As the proposed pathophysiology is swelling and entrapment of the nerve, some surgeons suggest surgical decompression of the nerve as a possible management option. This is an update of a review first published in 2011.
To assess the effects of surgery in the management of Bell's palsy.
On 29 October 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2012, Issue 10), MEDLINE (January 1966 to October 2012) and EMBASE (January 1980 to October 2012). We also handsearched selected conference abstracts for the original version of the review.
We included all randomised or quasi-randomised controlled trials involving any surgical intervention for Bell's palsy. We compared surgical interventions to no treatment, sham treatment, other surgical treatments or medical treatment.
Data collection and analysis
Two review authors independently assessed whether trials identified from the searches were eligible for inclusion. Two review authors independently assessed the risk of bias and extracted data.
Two trials with a total of 69 participants met the inclusion criteria. The first study considered the treatment of 403 people but only included 44 participants in the surgical trial, who were randomised into surgical and non-surgical groups. However, the report did not provide information on the method of randomisation. The second study randomly allocated 25 participants into surgical or control groups using statistical charts. There was no attempt in either study to conceal allocation. Neither participants nor outcome assessors were blind to the interventions, in either study. The first study lost seven participants to follow-up and there were no losses to follow-up in the second study.
Surgeons in both studies decompressed the nerves of all the surgical group participants using a retroauricular approach. The primary outcome was recovery of facial palsy at 12 months. The first study showed that the operated group and the non-operated group (who received oral prednisolone) had comparable facial nerve recovery at nine months. This study did not statistically compare the groups but the scores and size of the groups suggested that statistically significant differences are unlikely. The second study reported no statistically significant differences between the operated and control (no treatment) groups. One operated participant in the first study had 20 dB sensorineural hearing loss and persistent vertigo. We identified no new studies when we updated the searches in October 2012.
There is only very low quality evidence from randomised controlled trials and this is insufficient to decide whether surgical intervention is beneficial or harmful in the management of Bell's palsy.
Further research into the role of surgical intervention is unlikely to be performed because spontaneous recovery occurs in most cases.