Hemifacial spasm: conservative and surgical treatment options

Abstract

Background: Hemifacial spasm is a neuromuscular movement disorder characterized by brief or persistent involuntary contractions of the muscles innervated by the facial nerve. Its prevalence has been estimated at 11 cases per 100 000 individuals. Among the patients who were operated on by our team, the mean interval from diagnosis to surgery was 8.2 years, and more than half of them learned of the possibility of surgical treatment only through a personal search for information on the condition. These facts motivated us to write this article to raise the awareness of hemifacial spasm and its neurosurgical treatment among physicians who will encounter it.

Methods: This review article is based on a selective literature search and on our own clinical experience.

Results: Hemifacial spasm is usually caused by an artery compressing the facial nerve at the root exit zone of the brainstem. 85-95% of patients obtain moderate or marked relief from local injections of botulinum toxin (BTX), which must be repeated every 3 to 4 months. Alternatively, microvascular decompression has a success rate of about 85%.

Conclusion: Local botulinum-toxin injection is a safe and well-tolerated symptomatic treatment for hemifacial spasm. In the long term, however, lasting relief can only be achieved by microvascular decompression, a microsurgical intervention with a relatively low risk and a high success rate.

Figure 1

Patient with pronounced right-sided hemifacial spasm. Involvement of the platysma muscle is clearly visible

Figure 2

The axial-plane CISS sequence shows a loop of the posterior inferior cerebellar artery (Arrow A) which compresses the facial nerve (Arrow B), where it exists the brainstem

Figure 3

The figure shows the location of the lower retrosigmoidal craniotomy (Arrow)

Figure 4

Endoscopic image—taken using a 30°endoscope—shows the proximal part of the cochlear nerve (VIII) and the facial nerve with its root-exit zone (VII), which is compressed by a loop of the posterior inferior cerebellar artery (PICA) (same patient as in Figure 2)

Figure 5

The figure shows schematically the anatomical conditions in the cerebellopontine angle: V = trigeminal nerve, VIII = cochlear nerve, VII = facial nerve, IX = glossopharyngeal nerve, X = vagus nerve, XI = spinal accessory nerve

Figure 6

Different forms of vascular compression

Figure 7

After microsurgical dissection of the vessel from the facial nerve, a teflon sponge is placed between brainstem and vessel, in order to permanently prevent vascular compression (VII = facial nerve, PICA = posterior inferior cerebellar artery)