Surgical interventions for the early management of Bell's palsy

  • Review
  • Intervention

Authors


Abstract

Background

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.

Objectives

To assess the effects of surgery in the management of Bell's palsy.

Search methods

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.

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.

Plain language summary

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.

எளியமொழிச் சுருக்கம்

பெல்லஸ் பல்சிக்காக (நோய் மூலம் அறியா முகாவாதம்) அறுவை சிகிச்சை

பெல்ஸ் பால்சி என்பது முகத்தசைகளை, வழக்கமாக ஒரு பக்கத்தை மட்டும், செயலிழக்கச் செய்யும் நோயாகும். இது ஒரு மூலக் காரணம் அறியப்படாத நோயாகும். முகத்தில் உள்ள ஒரு நரம்பு இடுக்கத்தில் சிக்கிக் கொள்வது அல்லது வீக்கமடைவது போன்ற காரணங்களினால் ஏற்படலாம். பொதுவாக பெல்ஸ் பால்சியால் பாதித்த பெரும்பான்மையானவர்கள் குணமடைந்துவிடுவார்கள், இருப்பினும் சிலர் குணமடைவதில்லை. சில அறுவை சிகிச்சை மருத்துவர்கள் நரம்பை அறுவை சிகிச்சை மூலமாக இடுக்கத்திலிருந்து விடுவிப்பதன் மூலம் நோயை குணமடையச் செய்யலாம் என்று கருதினார்கள். எங்களுடைய இந்த பகுப்பாய்வு, பெல்ஸ் பால்சிக்கான அறுவை சிகிச்சையின் பயன்களை, சிகிச்சை எடுத்துக்கொள்ளாமல் இருப்பது, வேறு வகையான அறுவை சிகிச்சை முறை, போலி சிகிச்சை அல்லது பிற மருந்துகளை கொண்டு சிகிச்சை,ஆகியவற்றுடன் ஒப்பிட்டு மதிப்பிடுவதற்காக இந்த பகுப்பாய்வை மேற்கொண்டோம்.

இந்த பகுப்பாய்வுக்காக மேற்கொண்ட பரந்த தேடுதலின் விளைவாக இரண்டு பெல்ஸ் பால்சி உடையவர்களை சோதிக்கும் சமவாய்ப்பு கட்டுப்பாட்டு சோதனைகளை (RCT) கண்டறிந்தோம். இந்த இரண்டு சோதனைகளும் சேர்ந்து மொத்தம் 69 பெல்ஸ் பால்சி உடையவர்களை சோதனைக்கு உட்படுத்திருந்தது. 12 மாதத்தில் அறுவைசிகிச்சையின் விளைவாக எவ்வளவு குணமடைந்துள்ளனர் என்பதை முக்கிய அளவீடாக கருதி இந்த பகுப்பாய்வை மேற்கொண்டோம் முதலாவது ஆய்வு அறுவைசிகிச்சையை ஸ்டீராய்டு மருந்துடனும், மற்றும் இரண்டாவது சோதனை அறுவைசிகிச்சையை சிகிச்சையை எடுத்துக் கொள்ளாமல் இருப்பதுடன் ஒப்பீடு செய்திருந்தது. முதல் ஆய்வில், அறுவை சிகிச்சை மற்றும் அறுவை சிகிச்சை இல்லாத இரண்டு குழுக்களில், 9 மாதத்தில் நோய்குணமடைதல் ஒரேமாதிரியாகவே இருந்தது. இரண்டாவது ஆய்வில், அறுவைசிகிச்சை செய்துகொண்ட மற்றும் எந்த சிகிச்சையும் எடுத்துக் கொள்ளதவர்களுக்கும் இடையில், ஒரு வருடத்திற்குப் பின் நோய்குணமடைதலில் எந்தவிதவித்தியாசமும் கண்டறியப்படவில்லை. முதல் ஆய்வில் அறுவைசிகிச்சை செய்து கொண்ட ஒரு பங்கேற்பாளர்க்கு, சிகிச்சைக்குப் பிறகு மிதமான கேள்திறன் இழப்பு மற்றும் தலைசுற்றல் ஏற்பட்டது. இரண்டு ஆராய்ச்சிகளும், அதன் சோதனைமுடிவுகளை பாதித்திருக்ககூடிய குறைகளைக் கொண்டிருந்தன.

இந்த ஆய்வு முதலில் 2011 இல் வெளியிடப்பட்டது. நாங்கள் 2012 ம் ஆண்டு அக்டோபர் மாதம் தேடல்களை புதுப்பித்தோம், ஆனால் பொருத்தமான புதிய ஆராய்ச்சிகள் ஏதும் கிட்டவில்லை.

இந்த பகுப்பாய்வு மிகவும் தரம் குறைந்த ஆய்வுகளே உள்ளதாக கண்டறிந்துள்ளது மேலும் இந்தசான்றுகள், பெல்ஸ் பால்சி உடையவர்களுக்கு அறுவை சிகிச்சை பயனுள்ளதாக இருக்குமா அல்லது தீங்கானதாக இருக்குமா என்று முடிவெடுக்க போதுமானதாக இல்லை. பெல்ஸ் பால்சி பொதுவாக சிகிச்சை இல்லாமலேயே குணமடையக்கூடிய தன்மை கொண்டதால், இதில் அறுவை சிகிச்சையின் பங்களிப்புகுறித்து மேல் ஆராய்ச்சிகள் மேற்கொள்வதற்கான சாத்தியங்கள் குறைவு.

மொழிபெயர்ப்பு குறிப்புகள்

மொழி பெயர்ப்பு: இர.செந்தில் குமார், வை. பிரகாஷ் மற்றும் சி.இ.பி.என்.அர் குழு

Summary of findings(Explanation)

Summary of findings for the main comparison. Surgery for Bell's palsy versus medical treatment (oral prednisolone) or no treatment
  1. 1 Limitations in study design: in one study the method of randomisation was not described. There were small numbers in both studies and large numbers were not followed up in one study. One study followed participants up to 9 months not 12 months. In both studies there was unclear allocation concealment and outcome assessors were not blinded.
    2 No evidence of publication bias for this outcome.

Surgery for Bell's palsy
Patient or population: Bell's palsy
Settings: hospital attendance with idiopathic facial paralysis
Intervention: surgery
OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of Participants
(studies)
Quality of the evidence
(GRADE)
Comments
Assumed riskCorresponding risk
Control Surgery
Recovery of facial nerve function at 12 months
Follow-up: 12 months
See commentSee commentNot estimable69
(2 studies)
⊕⊝⊝⊝
very low 1,2
One study did not perform statistical analysis, one did not state the method used. Different outcome measures in each study made combining results impractical.
Side effects and complications of treatment
clinical assessment
Follow-up: 12 months
See commentSee commentNot estimable69
(2 studies)
⊕⊝⊝⊝
very low 1
The numbers involved in the included studies were small and statistical analysis was not possible.
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: confidence interval
GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

Background

Bell's palsy is an acute paralysis of one side of the face due to a lesion of the facial nerve. The condition is named after Sir Charles Bell, a Scottish surgeon (1774 to 1842). The cause is not known and Bell's palsy should only be used as a diagnosis in the absence of any other pathology. It was proposed in 1919 (Antoni 1919) that the underlying pathology was that of a viral neuropathy. Herpes simplex virus has been suggested as the likely pathogen (McCormick 1972) and animal studies have suggested that reactivation of the virus may lead to demyelination of the nerve leading to reduced function (Adour 1975; Stjernquist 2006).

The condition affects 25 to 35 people per 100,000 of the population per year and is most common in the 30 to 45 year age group. It is also more common in pregnant women, people with diabetes or people with a respiratory tract infection (Theil 2001). Recovery in most people can be expected to be good. It has been shown in a large review (Peitersen 2002) that over 70% of people with Bell's palsy will have normal function restored and of the remainder 25% will have slight or mild sequelae and only 4% will have severe sequelae. Contractures, facial disfigurement, with associated psychological difficulties, and facial pain (Morgenlander 1990) remain the most common long-term problems.

A number of studies have looked into identifying which population might benefit most from surgery. In addition to simple clinical assessment of disease using the House-Brackmann scale or similar, many studies have tried to assess the electrical function of the facial nerve. Electroneurography (ENOG) has been the most popular technique employed (Esslen 1977; Fisch 1984). In this the degree of muscle response to an electrically evoked stimulus is assessed. It was shown (Esslen 1977; Fisch 1984) that when 95% of the nerve had degenerated the patient had a 50% chance of a poor outcome (less than 50% chance of recovery to House-Brackmann grade 1 or 2) and would potentially benefit from surgical intervention (Sillman 1992).

Although Bell's palsy is a common condition, in the absence of an established aetiology, treatment continues to be based upon the presumed pathophysiology of swelling and entrapment of the nerve. Recent double-blind randomised controlled studies have shown that early treatment with prednisolone but not aciclovir significantly improves the chances of complete recovery, to 94% at nine months (Sullivan 2007; Engstrom 2008). Recent Cochrane reviews on the use of corticosteroids (Salinas 2010) and antivirals (Lockhart 2009) in Bell's palsy are consistent with these findings.

As the proposed pathophysiology involves entrapment of the nerve, this has led some surgeons to suggest that surgical decompression of the nerve is a suitable management option. The first recorded attempt at surgical decompression of the facial nerve for Bell's palsy was in 1932 (Ballance 1932). Ballance 1932 recommended slitting the sheath in the distal descending segment of the nerve. This was consistent with theories of the site of the lesion at that time. Over the next few decades, the proposed site for operation migrated from the distal 1 cm at the stylomastoid foramen (Ballance 1932) to the entrance of the Fallopian canal medially (Fisch 1972). The timing of surgery also varied from three months to immediately on onset (May 1972). In the early 1970s it was proposed that the most likely site of compression was at the entrance to the Fallopian canal (Fisch 1972). Intraoperative evoked electromyography (EMG) and an oedematous swelling at this point proximal to the geniculate ganglion was noted in up to 94% of their participants. In this study transmastoid/middle cranial fossa approaches were used to allow decompression of the nerve and geniculate ganglion. Other studies (May 1984) suggested that a transmastoid approach to decompression of the labyrinthine segment was of benefit. Two further studies published around the same time gave evidence both for (Giancarlo 1970) and against (McNeill 1974) operation. Because of the good outcome of the condition without treatment and with medical management and also the potential for damage to the facial nerve and other ear structures during surgery, there has been a continued debate as to whether surgery has a role in the management of Bell's palsy (Adour 2002; Friedman 2000).

Despite the debate on different surgical approaches there is a paucity of high quality evidence regarding facial nerve decompression surgery for acute Bell's palsy. Few large studies have been carried out. Of these one study (May 1985) convinced many surgeons that surgery did not have a place in the management of Bell's palsy. More recently, (Gantz 1999) found that when selected using ENOG, those patients who would have had a bad outcome as predicted by ENOG had a better outcome if surgically managed compared with those who were not. Currently most patients are managed medically with corticosteroids with or without aciclovir as discussed above. Surgery, certainly in the UK, is rarely undertaken (Sullivan 2007).

This is an update of a review first published in 2011.

Objectives

To assess the effects of surgery in the management of Bell's palsy.

Methods

Criteria for considering studies for this review

Types of studies

We assessed randomised controlled trials (RCTs) and quasi-RCTs in the main review. Quasi-RCTs are trials in which allocation of participants is partly systematic (for example by medical record number or by alternation). Other studies, including observational studies are included in the Discussion.

Types of participants

We included any participant (adult or child) who presented with an idiopathic facial palsy which was diagnosed as Bell's palsy. Those who were diagnosed as having herpes zoster, who had a traumatic aetiology or other identified aetiology were excluded from the review. This included any cases of recurrent and familial Bell's palsy or Melkerson-Rosenthal syndrome.

Types of interventions

We included any surgical intervention carried out for Bell's palsy. We compared these interventions to no treatment, sham treatment, other surgical treatments or medical treatment. Where concomitant treatment was given this was the same in both treatment and comparator groups.

Types of outcome measures

Primary outcomes

The primary outcome measure was the degree of recovery of facial nerve function and resolution of symptoms at 12 months as measured using the House-Brackmann scale, the Sunnybrook scale, the Yanigahara scale or other similar scale.

Secondary outcomes

1. Complete recovery at three and six months.
2. Synkinesis and contracture at 12 months.
3. Psychosocial outcomes at 12 months.
4. Side effects and complications of treatment.

We selected recovery of facial nerve function at 12 months, and side effects and complications of treatment for inclusion in a 'Summary of findings' table.

Search methods for identification of studies

Electronic searches

On 29 October 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register (29 October 2012), CENTRAL (2012, Issue 10 in The Cochrane Library), MEDLINE (January 1966 to October 2012) and EMBASE (January 1980 to October 2012).

We used the following phrases, adapted to each database as appropriate:
#1 (Bell's palsy) OR (Bell palsy) OR (idiopathic facial paralysis) OR (facial paralysis) OR (facial palsy) OR (facial nerve)
AND
#2 (surgery) OR (surg*) OR (operative) OR (operat*) OR (decompression) OR (decompres*).

For this update we also searched clinical trials registries for ongoing studies:

The detailed search strategies are in the appendices: Appendix 1 (CENTRAL), Appendix 2 (MEDLINE), Appendix 3 (EMBASE), Appendix 4 (ClinicalTrials.gov) and Appendix 5 (ICTRP).

Searching other resources

  1. We reviewed the bibliographies of all trials identified.

  2. We performed a handsearch of the following conference abstracts:

  • American Academy of Otolaryngology - Head and Neck Surgery Annual Meeting 2006 and 2007; and

  • British Academic Conference in Otolaryngology and ENT Expo Birmingham, UK, both 2006.

Data collection and analysis

Selection of studies

Two review authors (DW, KA) reviewed titles and abstracts identified by the search strategy. The review authors obtained the full text of all relevant studies and assessed them independently. Two review authors (DW, KA) assessed whether each trial met the inclusion criteria. They resolved any disagreement by discussion with the lead author (IS) where required.

Data extraction and management

The extracted data included study participants, methods, interventions used and outcomes, along with results and 95% confidence intervals (CIs). Two review authors extracted the data independently and entered them onto a specifically designed form.

Risk of bias

Two review authors independently assessed the risk of bias in the included studies using the Cochrane Collaboration's 'Risk of bias' tool described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2008, current version Higgins 2011). We addressed six 'Risk of bias' domains: sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and 'other sources of bias'. We judged each study in relation to each domain, as at a high, low or unclear risk of bias. We resolved any disagreement by discussion with the lead author (IS) where required.

Measures of treatment effect

There were insufficient studies to enable any statistical analysis. If in future updates, statistical analysis is possible we will enter data into the Review Manager (RevMan 2011) software and analyse the data using the standard statistical methods. For continuously measured outcomes we will use means to obtain mean differences (MDs) with 95% CI. For dichotomous outcome data we will estimate the pooled risk ratio (RR) with 95 % CI within the RevMan statistical package. We will calculate the number needed to treat for an additional beneficial effect (NNTB) or for an additional harmful effect (NNTH) if possible. We will combine observational RR if little trial evidence is found.

Assessment of heterogeneity

There were insufficient studies to enable any statistical analysis. Had there been sufficient studies, we would have performed a Chi2 test for homogeneity. If significant heterogeneity had been found, we would have tried to find the cause based on the characteristics of the studies included.

Assessment of reporting biases

There were insufficient studies to enable any statistical analysis. Had trials been available we would have assessed publication bias using a funnel plot.

Data synthesis

There were insufficient studies to enable any statistical analysis. If studies become available, initially, we will use a fixed-effect model and carry out the test for heterogeneity. Random-effects models such as DerSimonian and Laird account for more uncertainty and we will also utilise these, especially if there is unexplained heterogeneity (DerSimonian 1986).

Subgroup analysis and investigation of heterogeneity

There were insufficient studies and data sets were too small to enable statistical analysis. If statistical analysis becomes possible in the future, we will perform a sensitivity analysis omitting studies of high risk of bias. In addition, quality could be incorporated into mixed models simultaneously allowing for differences in quality using Bayesian methods, utilised in WinBUGS (Spiegelhalter 2000).

Economic issues

There was insufficient information in the included studies to discuss economic issues in the Discussion.

This review has a published protocol (McAllister 2008). We have documented changes from the protocol in Differences between protocol and review.

Results

Description of studies

The numbers of papers found by the current strategies were MEDLINE 469 (59 new), EMBASE 271 (33 new), Cochrane Neuromuscular Disease Group Specialized Register 12 (0 new) , CENTRAL 56. We found no relevant trials on searching trials registries (ClinicalTrials.gov and ICTRP).

After two authors had screened the results, we declared 67 papers potentially eligible. We then shortlisted 11 papers but subsequently excluded nine. Two trials met the inclusion criteria (Adour 1971; Mechelse 1971).

Adour 1971 considered the treatment of 403 patients but only included 44 participants in their surgical study. These participants were randomised into a surgical and non-surgical group. However, the non-surgical control group also contained those who refused surgery. Adour 1971 based inclusion in the study upon an extensive clinical examination, which the trial authors report took around two hours for the initial assessment. Clinically this involved a neurological examination, an ear, nose and throat (ENT) examination, X-rays of the mastoid and chest, audiogram and a group of blood tests including full blood count, erythrocyte sedimentation rate (ESR) and glucose. More specifically for the facial nerve function, they carried out serial four-point nerve excitability tests, electromyography and nerve conduction studies. The investigators included participants in the study if they met all of the following criteria: a clinically complete facial nerve palsy, no contraindication to general anaesthesia and an increasing nerve excitability shown by a difference between the affected and unaffected sides. The investigators excluded any participant that did not fit all three inclusion criteria. In addition, the study excluded participants with facial paralysis thought to be of any cause other than Bell's palsy. The report did not state the mechanism of randomisation. Three groups were selected: no surgery, surgery within 48 hours of onset of denervation, surgery 8 to 12 weeks after onset of denervation.  Some participants declined surgery and were added to the non-surgical group. Other than the numbers, the study stated no differences between the groups.

Mechelse 1971, randomly allocated 25 participants into surgical or control groups. Mechelse 1971 used similar initial assessments when compared to Adour 1971. Investigators selected participants on the basis of a complete facial palsy and electromyography showing no voluntary control of motor unit or a minimal applied current to evoke a motor response on the affected side 2.5 times that required on the unaffected side. These responses needed to be confirmed on two occasions a few days apart. The trial authors excluded participants with signs or symptoms suggestive of a cause for their facial paralysis other than Bell's palsy, those with incomplete facial paralysis, and those with an abnormality on ENT examination, skull X-ray or in blood and urine tests. One participant declined surgery and was removed from the study. This study reports the age and sex of the participants, and the side of the face affected but did not report if there were statistically significant differences between the two groups at baseline (see Characteristics of included studies).

Outcome criteria

Adour 1971 used the Facial Paralysis Recovery Profile (FPRP) and the Facial Paralysis Recovery Index (FPRI) to measure outcomes. The trial authors developed these measures for this study and used them for subsequent studies. The FPRP score ranges from +2 for no recovery +10 for complete recovery. The FPRI score ranges from -12 to +10 (FPRI is the FPRP score minus points for complications, +10 represents complete recovery without any complications). This study did not stipulate what score on the clinical scale constituted a satisfactory recovery.

Mechelse 1971 used a scale of 0 to 5 to assess outcome (0 = no function, 5 = complete function). The authors did not stipulate what value on the clinical scale represented a satisfactory recovery.

Both studies predate the development of the House-Brackmann scale.

Operative procedure

The participants in the surgical groups of both studies underwent facial nerve decompression using a retroauricular approach.

Excluded studies

Several studies were excluded on the basis of non-random selection of the control groups. Giancarlo 1970; Fisch 1981; Brown 1982; May 1984; Aoyagi 1988; Gantz 1999; McNeill 1974 and Yanagihara 2001 all had control groups that were self selected, in that participants who refused surgery became the control group. We did not feel therefore that comparisons made between the operated groups of participants and the control groups were valid, as the reasons the participants refused surgery may have been relevant to their outcomes. For example, in Yanagihara 2001, younger participants opted for surgery whereas older participants declined (see Characteristics of excluded studies).

Risk of bias in included studies

Allocation

Adour 1971 does not describe the method of randomisation that was used. Some participants who declined surgery were added to the non-surgical group. The report states, "the attempt at randomisation into equal groups was made. Completely random distribution could not be effected because some patients and some patients' physicians, refused surgical intervention."

Mechelse 1971 randomly allocated 25 participants into surgical or control groups. The report states that "in both hospitals these patients were entered on a list, previously prepared by the statistical department, University of Leiden (head, Mr H. De Jonge), which randomly allocated them to surgical treatment or to a control group". One participant declined surgery and was removed from the study.

Allocation concealment

Neither report mentioned any attempted method of allocation concealment.

Blinding

It was not possible in either study to blind participants to the surgical or non-surgical intervention. Also, neither study report commented on blinding of the investigator or outcome assessor and this would have been difficult to perform because of the surgical intervention involved.

Incomplete outcome data

In Adour 1971, 6/21 control participants and 1/23 participants in the operated group were lost to follow-up before the end of the nine-month study. The trial authors made no comment on reasons for loss to follow-up.

Mechelse 1971 claim to have followed all their participants for one year with no losses ("All patients were followed clinically and electromyographically for a least a year").

Selective reporting

Adour 1971 reported no statistical analysis of their data but reported on all pre-specified outcomes.

Mechelse 1971 did report statistical comparison between the groups but did not report the statistical methods used. All prespecified outcomes were reported in this study.

Other potential sources of bias

Both studies appear to be free of other sources of bias.

Review authors' judgements about each 'Risk of bias' item for each included study are summarised in Figure 1.

Figure 1.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study. Red = high risk of bias, yellow = unclear risk of bias, green = low risk of bias.

Effects of interventions

See: Summary of findings for the main comparison Surgery for Bell's palsy versus medical treatment (oral prednisolone) or no treatment

Primary outcome measure

Adour 1971 concluded that early or late surgical decompression of the facial nerve was not of benefit to people with Bell's palsy who have evidence of impending or actual denervation. Adour 1971 used the FPRP and FPRI scores to assess the degree of recovery of facial nerve function and resolution of symptoms at nine months. The study authors reported that the 21 participants who did not undergo surgery (who received oral prednisolone) had average outcome scores of +6 FPRP and +4 FPRI at nine months. The 10 participants who underwent surgery within 48 hours had average scores of +5 FPRP and +3 FPRI and the 13 participants who underwent surgery more than eight weeks post onset of denervation had average scores of +5 FPRP and +2 FPRI. The study authors do not statistically compare the groups but the scores given and size of the groups suggest that statistically significant differences are unlikely. 

Mechelse 1971 concluded that facial nerve decompression in the second or third week after the onset of paralysis did not increase the degree of recovery in participants with Bell's palsy. They reported that 11 participants were randomised to the operated group and 13 to the control group. They used a scale of 0 to 5 to assess outcome (0 = no function, 5 = complete function). Participants ranged in recovery from 2 to 5 on their scale and they reported no statistically significant differences between the surgical and non-surgical groups (P = 0.9).

Secondary outcome measures

Complete recovery at three and six months

Adour 1971 documents levels of recovery at three and six months but no statistical comparison was made.

In the Mechelse 1971 study, EMG follow-up showed that onset of recovery did not occur before the third month in both the surgical and non-surgical group. Facial nerve outcome scores were not documented for three and six months.

Synkinesis and contracture at 12 months

Adour 1971 listed individually synkinesis and other clinical features but did not compare the different study groups. The investigators found that almost all participants with evidence of denervation on nerve excitability testing had contracture and synkinesis by nine months.

In the Mechelse 1971 study, synkinesis and contractures were seen equally in the control and operated groups.

Psychosocial outcomes at 12 months

There was no mention of psychosocial outcomes in either study.

Side effects and complications of treatment

One participant in the Adour 1971 study had 20 dB sensorineural hearing loss and persistent vertigo. Tympanotomy showed injury to footplate and fibrous overgrowth. Removal of the overgrowth resulted in normal hearing and no further vertigo.

In the Mechelse 1971 study, no complications of surgery, such as wound dehiscence, infection, bleeding and numbness were reported.

Discussion

The evidence from the RCTs included in our study does not support surgical intervention for Bell’s palsy. The two trials included had relatively small numbers: 44 in the Adour 1971 and 25 in the Mechelse 1971 trial. Considered individually, the trials have too few participants for sufficient statistical power to detect the magnitude of effect that might plausibly be expected. Both trials stated that the participants were randomised into surgical and non-surgical (control) groups. However, the methods of randomisation were not clearly stated in either. Therefore, we cannot exclude the possibility of bias. In both studies there was unclear allocation concealment and outcome assessors were not blinded. Each study had similar inclusion criteria and only included patients with complete facial paralysis. The systems used in both studies to assess facial nerve function are less widely used in the assessment of Bell’s palsy than the House-Brackmann facial nerve grading system. There were different assessment systems used in each trial with no stipulated score that constituted recovery. These factors made combining the results for statistical analysis impractical (see Summary of findings for the main comparison).

The results from Mechelse 1971 did not show any statistically significant difference between the surgical intervention and control groups. No statistical analysis was conducted in Adour 1971 but the scores given and size of the groups suggest statistically significant differences were unlikely. Observational studies have shown contrasting results after surgical decompression of the facial nerve for Bell's palsy. Some studies showed statistically significant improvement in facial nerve function in the surgical groups compared to control groups (Giancarlo 1970; Fisch 1981; Gantz 1999). The studies mentioned all involved surgery on patients with complete facial paralysis and indicators of poor prognostic outcome but the numbers involved in each study were low. In contrast, other studies were unable to show any statistically significant differences between surgical and control groups (McNeill 1974; May 1984; Aoyagi 1988).

With regard to complications of surgery, one of the included studies reported that one participant developed 20 dB sensorineural hearing loss and persistent vertigo. The included studies did not report any other complications of surgery. Only a few observational studies have commented on postoperative complications after decompression of the facial nerve. In one study, one of 13 people who underwent surgery developed a 40 dB hearing loss at 8 KHz (Fisch 1981). In another, six out of 19 participants who had surgical decompression had significant hearing losses postoperatively (McNeill 1974).

The natural history of Bell’s palsy is spontaneous recovery in the majority of people and this review did not find any evidence to support surgical intervention in this condition.

Authors' conclusions

Implications for practice

There is only very low quality evidence from RCTs and this is insufficient to decide whether surgical intervention is beneficial or harmful in the management of Bell's palsy.

Implications for research

Further research into the role of surgical intervention is unlikely to be performed because spontaneous recovery occurs in most cases.

Acknowledgements

Angela Gunn, the Trials Search Co-ordinator of the Cochrane Neuromuscular Disease Group performed the searches.

The editorial base of the Cochrane Neuromuscular Disease Group is supported by the MRC Centre for Neuromuscular Diseases.

Data and analyses

Download statistical data

This review has no analyses.

Appendices

Appendix 1. CENTRAL search strategy

#1 MeSH descriptor Bell Palsy, this term only with qualifier: SU
#2 MeSH descriptor Facial Paralysis, this term only with qualifier: SU
#3 MeSH descriptor Hemifacial Spasm, this term only with qualifier: SU
#4 (bell NEAR/2 palsy or facial NEAR/2 palsy or facial NEAR/2 paralysis or facial NEAR/2 paresis)
#5 hemifacial NEAR/2 palsy OR hemifacial NEAR/2 paralysis OR hemifacial NEAR/2 paresis
#6 facial NEAR/2 palsy or facial NEAR/2 paralysis or facial NEAR/2 paresis
#7 (#4 OR #5 OR #6)
#8 surg* or operati* or decompressi*
#9 (#7 AND #8)
#10 (#1 OR #2 OR #3 OR #9)

Appendix 2. MEDLINE (OvidSP) search strategy

Database: Ovid MEDLINE(R) <1946 to October Week 3 2012>
Search Strategy:
--------------------------------------------------------------------------------
1 randomized controlled trial.pt. (339605)
2 controlled clinical trial.pt. (85425)
3 randomized.ab. (242346)
4 placebo.ab. (135629)
5 drug therapy.fs. (1578525)
6 randomly.ab. (173863)
7 trial.ab. (251056)
8 groups.ab. (1136962)
9 or/1-8 (2939707)
10 exp animals/ not humans.sh. (3797751)
11 9 not 10 (2497281)
12 bell palsy/ or facial paralysis/ or hemifacial spasm/ (11053)
13 ((bell$ or facial or hemifacial$) adj3 (pals$ or paralys$ or paresi$ or spasm$)).mp. (14834)
14 12 or 13 (14834)
15 surgery/ or (surg$ or operat$ or decompres$).mp. (1755416)
16 14 and 15 (4721)
17 bell palsy/su or facial paralysis/su or hemifacial spasm/su (2137)
18 16 or 17 (5313)
19 11 and 18 (473)
20 remove duplicates from 19 (469)
21 20 and 20101101:20121029.(ed). (59)

Appendix 3. EMBASE (OvidSP) search strategy

Database: Embase <1980 to 2012 Week 43>
Search Strategy:
--------------------------------------------------------------------------------
1 crossover-procedure.sh. (35377)
2 double-blind procedure.sh. (111601)
3 single-blind procedure.sh. (16569)
4 randomized controlled trial.sh. (331618)
5 (random$ or crossover$ or cross over$ or placebo$ or (doubl$ adj blind$) or allocat$).tw,ot. (908624)
6 trial.ti. (136873)
7 clinical trial/ (873297)
8 or/1-7 (1509541)
9 (animal/ or nonhuman/ or animal experiment/) and human/ (1217670)
10 animal/ or nonanimal/ or animal experiment/ (3327400)
11 10 not 9 (2754501)
12 8 not 11 (1420397)
13 limit 12 to embase (1101523)
14 Bell Palsy/ (2044)
15 Facial Nerve Paralysis/ (14433)
16 HEMIFACIAL SPASM/ (1760)
17 ((bell$ or facial or hemifacial$) adj3 (pals$ or paralys$ or paresi$ or spasm$)).mp. (20209)
18 or/14-17 (20209)
19 surgery/ or (surg$ or operat$ or decompres$).mp. (2485479)
20 18 and 19 (6726)
21 Bell Palsy/su or Facial Nerve Paralysis/su or HEMIFACIAL SPASM/su (2180)
22 20 or 21 (7173)
23 13 and 22 (271)

Appendix 4. ClinicalTrials.gov

In conditions section: "Bell's palsy" OR "Bell palsy" OR "idiopathic facial paralysis" OR "facial paralysis" OR "facial palsy" OR "facial nerve"

AND

In interventions section: "surgery" OR "surg*" OR "operative" OR "operat*" OR "decompression" OR "decompres"

Appendix 5. World Health Organization International Clinical Trials Registry Platform (ICTRP)

In title section: Bell's palsy OR Bell palsy OR idiopathic facial paralysis OR facial paralysis OR facial palsy OR facial nerve

What's new

DateEventDescription
9 October 2014AmendedCorrection to Background: removed statement that the condition was first described by Sir Charles Bell.

History

Protocol first published: Issue 4, 2008
Review first published: Issue 2, 2011

DateEventDescription
17 October 2013AmendedCorrected date of search in abstract
13 February 2013New citation required but conclusions have not changedNew search to 29 October 2012. Published notes included
29 October 2012New search has been performedThis review has been updated with a new search but no new relevant studies were identified. The text has been edited.

Contributions of authors

Miss K McAllister devised the search strategy, designed the protocol, assessed study quality, undertook data collection and analysis and wrote the review.

Mr D Walker devised the search strategy, designed the protocol, assessed study quality, undertook data collection and analysis and wrote the review.

Mr P Donnan provided statistical knowledge and expertise required for the protocol and review.

Mr I Swan suggested the review and supervised the writing of the protocol and the review.

Declarations of interest

None known.

Sources of support

Internal sources

  • No sources of support supplied

External sources

  • None, Other.

Differences between protocol and review

We have updated the 'Risk of bias' methodology since the protocol was published, in order to conform to the 2008 Cochrane methodology. We also added a 'Summary of findings' table and specified outcomes for inclusion in the table, in the methods section. We have stated the comparisons that we would consider for inclusion and clarified this in the methods section.

We included searches of trials registries.

Notes

As new evidence on this topic is slow to emerge, the next update of this review will take place four years from the date of search rather than at the usual two years. If trials are conducted, the review authors will schedule an earlier update.

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Adour 1971

MethodsRandomised controlled study conducted through a Facial Paralysis Research Clinic which received referrals from 14 various clinics (Permanente Medical group, Kaiser Foundation Hospital, Oakland, California). The study participants were followed up for 9 months. A parallel group of 264 participants with Bell's palsy not included in the study were followed up for 1 month
Participants

44 participants were included in the surgical study (considered the treatment of 403 patients)

Inclusion was based upon an extensive clinical examination.

Participants had to fit three criteria: a clinically complete nerve palsy, no contraindication to general anaesthesia and an increased nerve excitability shown by a difference between the affected and unaffected sides

Surgery group: 23 participants, mean age 36.8 years, male:female ratio 10:13

Control group: 21 participants, mean age 48.2 years, male:female ratio 8:13

Participants were members of Kaiser Foundation Health plan (paid health care programme of 900,000 subscribers) in San Francisco Bay area. General health of members, including age distribution were thought to be representative of the general population

Interventions

Participants were randomised into a surgical and non-surgical group. Interventions were: no surgery, surgery within 48 hours of onset of denervation, surgery 8 to 12 weeks after onset of denervation. Some participants declined surgery and were added to the non-surgical group.

All the participants in the operative group were decompressed using a retro-auricular approach. The non-surgical group were treated with prednisolone beginning with a dose of 40 mg and tapering to 5 mg at the end of eight days

Outcomes

Facial Paralysis Recovery Profile (FPRP) and the Facial Paralysis Recovery Index (FPRI) were used to measure outcomes. The scales were developed by the authors for this study and used for their subsequent studies. The FPRP score ranges from +2 for no recovery to +10 for complete recovery. The FPRI score ranges from -12 to +10 (the FPRP score minus points for complications)

Synkinesis and other clinical features listed individually but not compared between the different study groups

The outcomes were measured at 1, 2, 3, 6 and 9 months

NotesThe study was supported by a Public Health Service general research support grant from the National Institutes of Health. There was no declared conflicts of interest among the main researchers in the study
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)High risk

Quote: "the attempt at randomisation into equal groups was made. Completely random distribution could not be effected because some patients and some patients' physicians, refused surgical intervention."

Comment: The method of randomisation used was not described. Some participants who declined surgery were added to the non-surgical group

Allocation concealment (selection bias)Unclear riskThere was no mention of any attempted method of allocation concealment
Blinding (performance bias and detection bias)
All outcomes
High riskBlinding of the participant to either a surgical and non-surgical intervention was not possible. Blinding of the investigator/outcome assessor was not commented on and would have been difficult to perform in this study because of the surgical intervention involved
Incomplete outcome data (attrition bias)
All outcomes
High risk

Quote: "one patient was lost to follow-up"

Comment: 1/23 participants in the operated group was lost to follow-up and was commented on. However, 6/21 participants from the control group were lost to follow-up at the 9 month assessment (reasons not given) and other omissions in data are not mentioned in the text.

Selective reporting (reporting bias)Low riskAll pre-specified outcomes were reported on
Other biasLow riskAppears to be free of other sources of bias

Mechelse 1971

MethodsA randomised controlled study conducted simultaneously at 2 centres. Participants not included in the study because of good prognosis were also followed up. Both participants and the parallel study group were followed up for 1 year
Participants

25 participants were selected on the basis of a complete facial palsy and electromyography showing no voluntary control of motor unit or a minimal applied current evoking a motor response on the affected side 2.5 times that of the unaffected side. These responses needed to be confirmed on two occasions a few days apart. 1 participant refused surgery and was excluded from the study

Surgery group: 11 participants, mean age 45.3 years, male to female ratio 1:10, side of idiopathic facial palsy left:right = 7:4

Control group: 13 participants, mean age 45 years, male to female ratio 8:5, side of idiopathic facial palsy left:right = 6:7

This study did not report if there were statistically significant differences between the two groups

InterventionsAll the participants in the surgical group were decompressed using a retro-auricular approach. The control group had no treatment
OutcomesOutcome assessed using a scale of 0 to 5 (0 no function, 5 complete function). Study report does not state statistical methods used
Notes2 Centres participating in study: University Hospital, Leiden and Municipal Hospital, The Hague, Netherlands. There was no sponsorship noted. There was no declared conflicts of interest among the main researchers in the study
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk

Quote: "in both hospitals these patients were entered on a list, previously prepared by the statistical department, University of Leiden (head, Mr H. De Jonge), which randomly allocated them to surgical treatment or to a control group"

Comment: 25 participants were randomly allocated into surgical or control groups as stated above. It is stated that one participant declined surgery and was removed from the study

Allocation concealment (selection bias)Unclear riskThere is no comment on any attempted method of allocation concealment
Blinding (performance bias and detection bias)
All outcomes
High riskBlinding of the participant to either a surgical and non-surgical intervention was not possible. Report does not comment on blinding of the investigator/outcome assessor, which would have been difficult to perform in this study because of the surgical intervention involved
Incomplete outcome data (attrition bias)
All outcomes
Low risk

Quote: "All patients were followed clinically and electromyographically for a least a year"

Comment: complete follow-up with no losses

Selective reporting (reporting bias)Low riskAll pre-specified outcomes were reported
Other biasLow riskAppears to be free of other sources of bias

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Aoyagi 1988Included participants were not randomised into surgical or non-surgical groups
Brown 1982Retrospective audit. Study does not compare outcomes between the groups and does not describe how surgery and no-surgery groups were selected
Fisch 1981Retrospective study. No description is given as to how participants were allocated to the surgically treated or not surgically treated groups. No discussion about the non-surgical group. Only 14 participants underwent surgery
Gantz 1999No randomisation. Participants self selected whether or not to have surgery. 11 out of 30 participants offered surgery declined, therefore only 19 out of 169 evaluated had surgery
Giancarlo 1970No randomisation. Participants self selected whether or not to have surgery. Also, report does not describe the degree of baseline clinical palsy, merely that the nerve was degenerating
May 1984Prospective audit. No attempt at randomisation. Control group either self selected, considered poor surgical risk or had already received corticosteroids. 50 participants underwent surgery with a control group of 35. However, statistical comparison was performed on only the poorest prognostic groups of 25 surgical and 13 non-surgical participants which showed no statistically significant difference
McNeill 1974Retrospective audit. Participants self selected whether or not to have surgery. Control group either declined surgery or were considered poor surgical risk
Yanagihara 2001Participants had trial of corticosteroids initially before being considered for surgery. There was no randomisation. Participants self selected whether or not to have surgery. Report notes that younger participants opted for surgery and older participants refused surgery