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. [2]
Nicholas Andre first described trigeminal neuralgia in 1756. 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. During this procedure he noted compression of the nerve by vascular loops, and in 1932 proposed the theory that trigeminal neuralgia was caused by compression of the nerve by blood vessels, typically the superior cerebellar artery. [3] With the advent of the operative microscope, Peter J. Jannetta was able to further confirm this theory in 1967 and advocated moving the offending vessel and placing a sponge to prevent the vessel from returning to its native position as a treatment for trigeminal neuralgia. [4]
Patients most likely to benefit from a microvascular decompression have a classic form of trigeminal neuralgia. [5] The diagnosis of this disorder is on the basis of the patients' symptoms and from a neurological examination. No blood test or genetic marker exists to diagnose the disease. An MRI scan can help eliminate other diagnoses. Newer MRI techniques may allow for the visualization of vascular compression of the nerve. Patients who improve with an MVD are likely to have pain which is episodic rather than constant. The pain typically has an electrical quality to it and is intense. The pain can usually be triggered. Common triggers include light touch, eating, talking or putting on make-up. Most patients whose face pain improved with an MVD also improved at least temporarily with medication.
In addition to having the proper type of pain, candidates for an MVD must also be healthy enough to undergo surgery. The risk of surgery may increase with increasing patient age.
Patients are put to sleep using general anaesthesia and are positioned on their back with their head turned or on their side with the symptomatic side facing up. Electrical monitoring of facial function and hearing is used. A straight incision is made two finger-breadths behind the ear about the length of the ear. A portion of the skull around 30 mm (1.2 inches) in diameter is removed exposing the underlying brain covering known as the dura. The dura is opened to expose the cerebellum. The cerebellum is allowed to fall out of the way exposing the side of the brainstem. Using a microscope or endoscope and micro-instruments, the arachnoid membrane is dissected allowing visualization of the 8th, 7th and finally the trigeminal nerve. The offending loop of blood vessel is then mobilized. Frequently a groove or indentation is seen in the nerve where the offending vessel was in contact with the nerve. Less often the nerve is thin and pale. Once the vessel is mobilized a sponge like material is placed between the nerve and the offending blood vessel to prevent the vessel from returning to its native position.
After the decompression is complete, the wound is flushed clean with saline solution. The dura is closed in a watertight fashion. The skull is reconstructed and the overlying tissues are closed in multiple layers. The patient is allowed to wake up and is taken to an intensive care unit or other close observation unit. [6]
The largest reported series of MVDs was reported by Jannetta and published in The New England Journal of Medicine in 1996. The initial success rate was 82% for complete relief with an additional 16% having partial relief for a combined initial success rate of 98%. At 10 year follow-up, 68% had excellent or good relief. 32% had recurrent symptoms. [7] Other series report similar or better results. [8]
Serious complications from an MVD include death (0.1%), stroke (1%), hearing loss (3%) and facial weakness (0.5%). 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.
Other complications include leakage of spinal fluid and wound infection (1%). 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. [9]
Several other surgical procedures exist for the treatment of trigeminal neuralgia, including percutaneous rhizotomy, percutaneous glycerol injection, percutaneous balloon compression, rhyzotomy and stereotactic radiosurgery (SRS). When compared to the other procedures, MVD carries the highest long-term success rate, but it also carries the highest risk.[ citation needed ] [10]
The foramen ovale is a hole in the posterior part of the sphenoid bone, posterolateral to the foramen rotundum. It is one of the larger of the several holes in the skull. It transmits the mandibular nerve, a branch of the trigeminal nerve.
Trigeminal neuralgia, also called Fothergill disease, tic douloureux, trifacial neuralgia, or suicide disease, is a long-term pain disorder that affects the trigeminal nerve, the nerve responsible for sensation in the face and motor functions such as biting and chewing. It is a form of neuropathic pain. There are two main types: typical and atypical trigeminal neuralgia.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
Neuralgia is pain in the distribution of a nerve or nerves, as in intercostal neuralgia, trigeminal neuralgia, and glossopharyngeal neuralgia.
Occipital neuralgia (ON) is a painful condition affecting the posterior head in the distributions of the greater occipital nerve (GON), lesser occipital nerve (LON), third occipital nerve (TON), or a combination of the three. It is paroxysmal, lasting from seconds to minutes, and often consists of lancinating pain that directly results from the pathology of one of these nerves. It is paramount that physicians understand the differential diagnosis for this condition and specific diagnostic criteria. There are multiple treatment modalities, several of which have well-established efficacy in treating this condition.
Hemifacial spasm (HFS) is a rare neuromuscular disease characterized by irregular, involuntary muscle contractions (spasms) on one side (hemi-) of the face (-facial). The facial muscles are controlled by the facial nerve, which originates at the brainstem and exits the skull below the ear where it separates into five main branches.
The superior cerebellar artery (SCA) is an artery of the head. It arises near the end of the basilar artery. It is a branch of the basilar artery. It supplies parts of the cerebellum, the midbrain, and other nearby structures. It is the cause of trigeminal neuralgia in some patients.
The superior ganglion of the vagus nerve is a sensory ganglion of the peripheral nervous system. It is located within the jugular foramen, where the vagus nerve exits the skull. It is smaller than and proximal to the inferior ganglion of the vagus nerve.
A neurectomy, or nerve resection is a neurosurgical procedure in which a peripheral nerve is cut or removed to alleviate neuropathic pain or permanently disable some function of a nerve. The nerve is not intended to grow back. For chronic pain it may be an alternative to a failed nerve decompression when the target nerve has no motor function and numbness is acceptable. Neurectomies have also been used to permanently block autonomic function, and special sensory function not related to pain.
Hypoesthesia or numbness is a common side effect of various medical conditions that manifests as a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is generally referred to as numbness.
Geniculate ganglionitis or geniculate neuralgia (GN), also called nervus intermedius neuralgia, Ramsay Hunt syndrome, or Hunt's neuralgia, is a rare disorder characterized by severe paroxysmal neuralgic pain deep in the ear, that may spread to the ear canal, outer ear, mastoid or eye regions. GN may also occur in combination with trigeminal or glossopharyngeal neuralgia.
A laminotomy is an orthopaedic neurosurgical procedure that removes part of the lamina of a vertebral arch in order to relieve pressure in the vertebral canal. A laminotomy is less invasive than conventional vertebral column surgery techniques, such as laminectomy because it leaves more ligaments and muscles attached to the spinous process intact and it requires removing less bone from the vertebra. As a result, laminotomies typically have a faster recovery time and result in fewer postoperative complications. Nevertheless, possible risks can occur during or after the procedure like infection, hematomas, and dural tears. Laminotomies are commonly performed as treatment for lumbar spinal stenosis and herniated disks. MRI and CT scans are often used pre- and post surgery to determine if the procedure was successful.
Laminoplasty is an orthopaedic/neurosurgical surgical procedure for treating spinal stenosis by relieving pressure on the spinal cord. The main purpose of this procedure is to provide relief to patients who may have symptoms of numbness, pain, or weakness in arm movement. The procedure involves cutting the lamina on both sides of the affected vertebrae and then "swinging" the freed flap of bone open thus relieving the pressure on the spinal cord. The spinous process may be removed to allow the lamina bone flap to be swung open. The bone flap is then propped open using small wedges or pieces of bone such that the enlarged spinal canal will remain in place.
Atypical trigeminal neuralgia (ATN), or type 2 trigeminal neuralgia, is a form of trigeminal neuralgia, a disorder of the fifth cranial nerve. This form of nerve pain is difficult to diagnose, as it is rare and the symptoms overlap with several other disorders. The symptoms can occur in addition to having migraine headache, or can be mistaken for migraine alone, or dental problems such as temporomandibular joint disorder or musculoskeletal issues. ATN can have a wide range of symptoms and the pain can fluctuate in intensity from mild aching to a crushing or burning sensation, and also to the extreme pain experienced with the more common trigeminal neuralgia.
Nerve compression syndrome, or compression neuropathy, or nerve entrapment syndrome, is a medical condition caused by chronic, direct pressure on a peripheral nerve. It is known colloquially as a trapped nerve, though this may also refer to nerve root compression. Its symptoms include pain, tingling, numbness and muscle weakness. The symptoms affect just one particular part of the body, depending on which nerve is affected. The diagnosis is largely clinical and can be confirmed with diagnostic nerve blocks. Occasionally imaging and electrophysiology studies aid in the diagnosis. Timely diagnosis is important as untreated chronic nerve compression may cause permanent damage. A surgical nerve decompression can relieve pressure on the nerve but cannot always reverse the physiological changes that occurred before treatment. Nerve injury by a single episode of physical trauma is in one sense an acute compression neuropathy but is not usually included under this heading, as chronic compression takes a unique pathophysiological course.
The Dextroscope is a medical equipment system that creates a virtual reality (VR) environment in which surgeons can plan neurosurgical and other surgical procedures.
The trigeminal artery is an artery that supplies the basilar artery with blood during human embryonic development. Normally, the trigeminal artery involutes after the formation of the posterior communicating artery. However, in some cases, the artery persists into adulthood and can cause medical complications, including intracranial aneurysms.
John Howard Sampson is an American neurosurgeon who was formerly chief of the department of neurosurgery at Duke University where he serves as a professor of surgery, biomedical engineering, immunology, and pathology.
Peter Joseph Jannetta was an American neurosurgeon known for devising microvascular decompression, a surgical procedure to treat trigeminal neuralgia. At the University of Pittsburgh School of Medicine, he was the first Walter Dandy Professor of Neurological Surgery.
A nerve decompression is a neurosurgical procedure to relieve chronic, direct pressure on a nerve to treat nerve entrapment, a pain syndrome characterized by severe chronic pain and muscle weakness. In this way a nerve decompression targets the underlying pathophysiology of the syndrome and is considered a first-line surgical treatment option for peripheral nerve pain. Despite treating the underlying cause of the disease, the symptoms may not be fully reversible as delays in diagnosis can allow permanent damage to occur to the nerve and surrounding microvasculature. Traditionally only nerves accessible with open surgery have been good candidates, however innovations in laparoscopy and nerve-sparing techniques made nearly all nerves in the body good candidates, as surgical access is no longer a barrier.