Microvascular decompression (MVD), also known as the Jannetta procedure,[1] is a neurosurgical procedure used to treat trigeminal neuralgia (along with other cranial nerve neuralgias), a pain syndrome characterized by severe episodes of intense facial pain, and hemifacial spasm.
The procedure is also used experimentally to treat tinnitus and vertigo caused by vascular compression on the vestibulocochlear nerve.
In 1891 Sir Victor Horsley proposed the first open surgical procedure for the disorder involving the sectioning of preganglionic rootlets of the trigeminal nerve.
Walter Dandy in 1925 was an advocate of partial sectioning of the nerve in the posterior cranial fossa.
A portion of the skull around 30 mm (1.2 inches) in diameter is removed exposing the underlying brain covering known as the dura.
Using a microscope or endoscope and micro-instruments, the arachnoid membrane is dissected allowing visualization of the 8th, 7th and finally the trigeminal nerve.
Dr. Jannetta has called facial paralysis (as opposed to weakness) a "major and common complication of the MVD."
(2 separate depositions under oath: Levy v Jannetta, CCP Allegheny County, GD 81–7689.
Most patients will have transient neck pain and stiffness from the surgical incision and from seeding of the spinal fluid with small amounts of blood.