Surgical operation for Bell's palsy (idiopathic facial paralysis)

Bell’s palsy is a paralysis of the muscles of the face, usually on one side, that has no known underlying cause. The symptoms probably occur when a nerve in the face is trapped and swollen. People with Bell's palsy generally recover but there is a small group who do not. Some surgeons have thought that an operation to free the nerve could improve recovery. We did this review to assess the effects of surgery for Bell's palsy compared with no treatment, other types of surgery, sham (fake) treatment or treatment with medicines.

After a wide search for randomised controlled trials, we found two studies to include in our review, which together involved 69 people with Bell's palsy. Our main measure of the effects of surgery was to be the recovery of paralysis at 12 months. The first study compared surgery with a steroid medicine and the second study compared surgery with no treatment. In the first study the surgery and no surgery groups appeared to have similar facial nerve recovery at nine months. The second study found no differences in recovery of the facial paralysis after one year, between the participants who had an operation and those who had no treatment. One participant who had surgery in the first study had mild hearing loss and vertigo (dizziness) afterwards. Both studies had limitations that could have affected the results.

This review was first published in 2011. We updated the searches in October 2012 and found no new relevant studies.

The review found that there was only very low quality evidence and that this was insufficient to decide whether an operation would be helpful or harmful for people with Bell's palsy. There is unlikely to be further research into the role of an operation because Bell's palsy usually recovers without treatment.

Authors' conclusions: 

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.

Read the full abstract...

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.

Search strategy: 

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.

Selection criteria: 

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.

Main results: 

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.