Hemifacial Spasm Associated with Chiari Type I Malformation: Surgical Considerations and Case Report

Hemifacial spasm (HS) is a movement disorder characterized by paroxysmal and irregular contractions of the muscles innervated by the facial nerve. Chiari malformation type I (CM I) is a congenital disease characterized by caudal migration of the cerebellar tonsils, and surgical decompression of foramen magnum structures has been used for treatment. The association of HS with CM I is rare, and its pathophysiology and therapeutics are speculative. There are only a few cases reported in the literature concerning this association. The decompression of the posterior fossa for the treatment of CM I has been reported to relieve the symptoms of HS, suggesting a relation between these diseases. However, the possible complications of posterior fossa surgery cannot be underrated. We report the case of a 66-year-old patient, in ambulatory follow-up due to right HS, no longer responding to botulinum toxin treatment. Magnetic resonance imaging (MRI) of the skull revealed compression of the facial nerve and CM I. The patient underwent surgery for HS by neurovascular microdecompression of the facial nerve via right lateral suboccipital craniectomy, but presented significant clinical worsening in the postoperative period even though the cerebellum edema related to surgical manipulation was mild. Due to the clinical worsening, the patient underwent a median suboccipital craniectomy with decompression of the foramenmagnum structures. After this second surgery, the patient had progressive improvement and was discharged from the hospital for ambulatory care.

Microvascular Compressicaude by Slinging a Tortuous Vertebrobasilar Artery to the Petrous Dura in Hemifacial Spasm: Technical Note

Objective In cases of hemifacial spasm caused by a tortuous vertebrobasilar artery (TVBA), the traditional treatment technique involves Teflon (polytetrafluoroethylene), which can be ineffective and fraught with recurrence and neurological complications. In such cases, there are various techniques of arteriopexy using adhesive compositions, 'suspending loops' made of synthetic materials, dural or fascial flaps, surgical sutures passed around or through the vascular adventitia, as well as fenestrated aneurysmal clips. In the present paper, we describe a new technique of slinging the vertebral artery (VA) to the petrous dura for microvascular decompression (MVD) in a patient with hemifacial spasm caused by a TVBA. Method A 50-year-old taxi driver presented with a left-sided severe hemifacial spasm. A magnetic resonance imaging (MRI) scan of the brain showed a large tortuous left-sided vertebral artery impinging and compressing the exit/entry zone of the 7th and 8th nerve complex. After a craniotomy, a TVBAwas found impinging and compressing the entry zone of the 7th and 8th nerve complex. Arachnoid bands attaching the artery to the nerve complex and the pons were released by sharp microdissection. Through the upper part of the incision, a 2.5 1 cmtemporal fascia free flap was harvested. After the fixation of the free flap, a 6­0 prolene suture was passed through its length several times using the traditional Bengali sewing and stitching techniques to make embroidered quilts called Nakshi katha. The'prolenated' fascia was passed around the compressing portion of the VA. Both ends of the fascia were brought together and stitched to the posterior petrous dura to keep the TVBA away from the 7th and 8th nerves and the pons. Result The patient had no hemifacial spasm immediately after the recovery from the anesthesia. A postoperative MRI of the brain showed that the VA was away from the entry zone of the 7th and 8th nerves.

Clinical Usefulness of Magnetic Resonance Cisternography in Patients Having Hemifacial Spasm

To evaluate the usefulness of MR cisternography fourteen patients that had hemifacial spasm and 20 control patients underwent MR cisternography. All the patients with hemifacial spasm had a confirmed vascular compression after surgery. MR cisternography was performed using a 1.5-tesla superconducting MR magnet in which a 3D (dimensional) heavily T2-weighted turbo spin-echo sequence was used. In 34 randomly selected individuals, we retrospectively determined whether MR cisternography images could be used to evaluat symptoms, and what the benefits of obtaining this image was. The results were correlated with the surgical findings. The sensitivity was 100% and the specificity was 94% in all patients having a hemifacial spasm. The offending vessels were the anterior inferior cerebellar artery (AICA) in six patients cases, the posterior inferior cerebellar artery (PICA) in six, both the vertebral artery and PICA in one, and the vertebral artery in one. All the images showed good resolution and contrast, and also showed the exact correlation between the facial nerve and intracranial vessels in the multiplaner image. The findings of neurovascular compression were well correlated with the surgical findings. We believe that high-resolution 3D MR cisternography is a very useful method for evaluating the neurovascular compression in patients that have hemifacial spasm.