Trigeminal Neuralgia

Trigeminal neuralgia results from irritability of the 5th cranial nerve, and is characterized by intense radiating pain involving the face over the distribution of one or several branches of the trigeminal nerve. The pain is frequently severe, can last from seconds to hours, and may be completely disabling. Although surgical treatment of this condition frequently is successful, medical management is usually initially employed. Commonly prescribed agents for trigeminal neuralgia include Dilantin, Tegretol and Lioresal. Many patients experience pain relief with medical therapy; however, side effects from these pharmaceuticals can be a problem. Tolerance to these medications can develop as well, reducing their effectiveness.

A variety of surgical procedures are employed in cases at the Illinois Neurological Institute where medical therapy has been unsuccessful, including microvascular decompression, mechanical balloon compression, glycerol rhizotomy, peripheral nerve section, and percutaneous radiofrequency rhizotomy. On average, surgery provides pain relief in approximately 75% of patients with trigeminal neuralgia. However, complications from surgery may occur, including loss of sensation of the face, hearing problems, as well as other surgical complications. Elderly patients may be at increased risk for many of these problems. Persistence or recurrence of pain despite surgery may also occur.

Radiosurgery was first used to treat trigeminal neuralgia in 1951 using a prototype orthovoltage radiosurgical device. More recently, the advent of magnetic resonance imaging (MRI) made precise localization of the trigeminal nerve feasible for radiosurgery treatment planning. The development of the Gamma Knife enabled small field radiosurgery using multiple 4mm radiation beams to be possible; the Gamma Knife's extraordinary accuracy is essential for radiosurgical treatment of trigeminal neuralgia.

Significant long-term pain relief is achieved in approximate three-fourths of patients who undergo radiosurgery; the median time to achieve pain relief is one month. Additionally, radiosurgery has an attractive safety profile compared with other surgical alternatives. Approximately 10% of patients develop new facial sensory symptoms such as numbness after radiosurgery, and the incidence of hearing loss reported in the literature is 0%. Significantly, other surgical risks of infection, hemorrhage, and cardiac and pulmonary complications are avoided. Radiosurgery is a safe and effective treatment alternative which should be considered when medical therapy of trigeminal neuralgia is unsuccessful or inadequate.

References
Kondziolka D. et al: Gamma Knife Radiosurgery for Trigeminal Neuralgia. in Gamma Knife Brain Surgery. Prog Neurol Surg. Basel, Karger, 1998, vol 14, pp 212-221

Young R. et al: Gamma Knife Radiosurgery for Treatment of Trigeminal Neuralgia: Idiopathic and Tumor Related. Neurology 1997;48(3):608-614

Kondziolka D. et al: Stereotactic Radiosurgery for Trigeminal Neuralgia: A Multiinstitutional Study Using the Gamma Unit. J. Neurosurg 84:940-945, 1996