Page 28 - Delaware Medical Journal - January/February 2020

The Role of CyberKnife Radiosurgery in the Management of Trigeminal Neuralgia
Sohan Shah; Serguei Castaneda, MD; Matthew Dzeda; Sunjay Shah, MD INTRODUCTION
Trigeminal neuralgia (TN) is a debilitating condition characterized
by recurrent episodes of severe lancinating facial pain due to trigeminal nerve dysfunction. As the pain can become unbearable, TN is colloquially known as “the suicide disease.”1 Although currently TN is
not felt to be curable, newer treatments can help to ameliorate pain with a lower risk of late complications such
as permanent facial numbness. Most
of TN cases occur between 60 and 70 years of age.2 The incidence of TN is approximately four per 100,000 people. Women are affected more than men, with a ratio of 1.7 to 1.3
PATHOPHYSIOLOGY
There are two types of TN, classical and secondary. Classical TN is caused by compression of the trigeminal nerve by small blood vessels, which causes damage to the myelin sheath surrounding the neuronal axons.4 It
is characterized by cycles of intense pain followed by pain-free intervals. The other type of TN, secondary
TN, is caused by another process,
such as multiple sclerosis or tumor compression, with the pain of TN being only a secondary symptom. It is more characterized by constant pain. The treatment for secondary TN involves treating the underlying disease rather than the pain.3
Figure 1. CyberKnife plan of a patient with trigeminal neuralgia treated with 99Gy in three fractions using a CISS MRI image
DIAGNOSIS
From a clinical perspective, the typical presentation of TN is a complaint of unilateral facial pain (involving one or two branches of the trigeminal nerve), which can be described as sharp or stabbing. Typical triggers for the pain include chewing, talking, brushing, touching one’s face, or feeling a light breeze. In addition, some patients have trigger zones, which are small areas near the nose or mouth at which even a small amount of stimulation can trigger a painful attack.3 The patient will know exactly where their trigger zones are and will avoid them at all costs. While trigger zones aren’t present in all TN patients, the presence of trigger zones should point to a diagnosis of TN. Deviations from these typical symptoms are called atypical symptoms and increase the likelihood of secondary
TN or even another entity such as depression. Examples of atypical symptoms include a chronic dull ache or sensations of facial numbness and tingling. Other atypical symptoms include hypersensitivity to light touch or facial spasms.4 Atypical TN is more refractory to conventional treatment modalities.
MANAGEMENT
There are many treatments for TN. The most common ones are medications, such as carbamazepine (Tegretol)
and oxcarbazepine; surgery, such as microvascular decompression, glycerol rhizotomy, and balloon compression; and stereotactic radiosurgery (SRS), such as Gamma Knife and CyberKnife. Each method varies in its success and complication rates.
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Del Med J | January/February 2020 | Vol. 92 | No. 1