facial nerve paralysis

The currently accepted treatment for facial nerve paralysis is surgery. Researchers question whether surgery is the best option and report results from a study examining non-surgical treatments.

The facial nerve can become paralyzed following trauma to the side of the face, such as that sustained in a car accident. One function of nerves is to send messages from the brain to muscles to tell them how to move. Therefore a consequence of facial nerve paralysis is the loss of proper use of the muscles of the face. Other consequences can include the loss of taste sensation and the loss of production of saliva and tears. The severity of this loss of function can vary between patients depending on the degree of trauma. The nerve may have been completely transected by a shard of fractured bone for example or may be slightly compressed by surrounding swelling.

In patients with complete facial nerve paralysis, the generally accepted recommendation among surgeons is to perform a nerve decompression surgery, ideally as soon as possible, to optimize the chances of recovery of function of this nerve. The authors of a recently published study in JAMA Otolaryngology-Head and Neck Surgery describe the surgery as essentially an exploration of the path of the nerve to identify the cause of the loss of function and rectify it if possible.

Is Surgery the Best Option to Treat Facial Nerve Paralysis?

Although the above-described rationale for surgery appears intuitive and is currently accepted, the researchers argue that there is actually no evidence to support that it is the best treatment approach for patients with facial nerve paralysis. Furthermore, in recent times, the availability of superior diagnostic imaging, such as high resolution computed tomography (HRCT), actually allows the path of the nerve to be evaluated in a non-surgical fashion. The authors state that whilst a positive finding on an HRCT, such as a fracture fragment pressing on the nerve, may give an indication for surgery, a wait-and-see approach may be advantageous in patients without a clear indication for surgery following an HRCT.

Based on this rationale, the researchers designed a study to answer the question of whether non-surgical treatment in patients that have complete or almost complete facial nerve paralysis, with no evidence of fracture fragments compressing the nerve, is viable. Patients in India who met these criteria and who provided informed consent were enrolled in the study. A total of 28 patients who had facial nerve paralysis following a head injury were assessed with an HRCT, and had testing performed on the nerve and the muscles that the nerve works upon to ascertain the degree of function. The patients were then given a corticosteroid for five weeks. This is a powerful anti-inflammatory medication that works to decrease any swelling and inflammation associated with the trauma.

For the next four and a half months the patients were then assessed by a health professional every two weeks and assessment of muscle function was undertaken every four weeks. Additionally, testing of the functional unit of nerve and muscle together continued until the first signs of recovery. The results of the assessment of nerve and fibre function were evaluated using three different types of grading systems.

Corticosteroid Eliminated the Need for Surgery

The study was designed such that if any patient had signs of deterioration of nerve function rather than improvement, or zero signs of improvement, a surgical intervention was made. The researchers remained in communication with the patients until at least nine months after the last treatment.

Out of the 28 patients enrolled in the study, 26 had a fracture of the temporal bone, which lies next to the nerve. The HRCT revealed that the fracture did not interfere with the course of the nerve, and was termed non-displaced or minimally displaced. For the first four weeks following enrollment in the study, no improvement in facial nerve paralysis was seen in any patient. By the 12-week mark, an improvement was seen in 27 out of 28 patients. The remaining patient took until week 20 for an improvement to be seen and surgery, although scheduled was eventually not performed.

At the endpoint of the study, which was nine months following enrollment, 15 patients appeared completely normal, 12 patients had only a slight weakness, and one patient had moderate dysfunction from facial nerve paralysis which was obvious but not disfiguring.

Recovery Without Surgery

The researchers concluded that a good quality recovery from facial nerve paralysis, although delayed was almost universal. It is only valid, however, to generalize the results of this study to patients that have non-displaced fractures of the temporal bone, as those are the patients from which these results have been obtained.

This is the first study to provide evidence-based support to non-surgical treatment of patients with facial nerve paralysis. The researchers note that although the improvement is delayed until at least 6-12 weeks following injury, reports from patients who had surgical decompression in the first four weeks following injury, in fact, have improvement within a similar time frame. The researchers, therefore, discuss that it is difficult to discern whether such improvement in the surgically treated patients was from surgical decompression or was going to occur anyway, as shown in the group of patients upon which they report.

Avoiding unnecessary surgery is important to reduce complications that can occur following surgical decompression for facial nerve paralysis. A previous study of 156 patients revealed a 15% occurrence of significant adverse effects which were induced by the surgery itself and not the initial road traffic accident trauma. These included complications as serious as seizures, hearing loss, and meningitis, among others. The authors discuss that, in this day and age, when sophisticated imaging equipment such as HRCT is available, such surgical risks are not justifiable, particularly in light of the excellent prognosis reported with non-surgical treatment.

Written by Nicola Cribb, VetMB DVSc Dip.ACVS

References:

(1) Thakar A, Gupta M, Srivastava A, Agrawal D, Kumar A. Nonsurgical Treatment for Posttraumatic Complete Facial Nerve Paralysis. Jama Otolaryngology Head Neck Surg 2018.
(2) House JW, Brackmann DE. Facial nerve grading system. Otolaryngol Head Neck Surg 1985;93:146–7.

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