Microvascular decompression

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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]

History

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]

Patient selection

Patients most likely to benefit from a microvascular decompression have a classic form of trigeminal neuralgia.

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.

Surgical technique

Patients are put to sleep using

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 sewn closed. 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.

Results

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.[6] Other series report similar or better results.[7]

Complications

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.[8]

Other procedures

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][9]

References

  1. ^ "Trigeminal Neuralgia FAQ".
  2. PMID 27911239
    .
  3. ^ Dandy WE. Trigeminal neuralgia and trigeminal tic douloureux. In: Lewis D, ed. Practice of Surgery. Hagerstown, MD: WF Prior CO, 1932: 177-200.
  4. ^ Jannetta PJ. Arterial compression of the trigeminal nerve at the pons in patients with trigeminal neuralgia. Journal of Neurosurgery 1967: 26: 159-162.
  5. PMID 34674027
    .
  6. ^ Barker FG II, Jannetta PJ, Bissonette DJ, et al. The long-term outcome of microvascular decompression for trigeminal neuralgia. New England Journal of Medicine 1996; 334: 1077-1083.
  7. ^ Apfelbaum RI. Neurovascular decompression - the procedure of choice? In: Grady MS, ed. Clinical Neurosurgery, Vol 46. Baltimore: Williams & Wilkins, 2000.
  8. ^ Weigel G and Casey K. Striking Back! The trigeminal neuralgia handbook. Trigeminal Neuralgia Association Press. Gainesville, Florida 2000.
  9. ^ "The long-term clinical outcomes of microvascular decompression for treatment of trigeminal neuralgia compressed by the vertebra-basilar artery: a case series review".
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