Classification Systems for Trigeminal Neuralgia and Quantification of Facial Pain

Classification Systems For Trigeminal Neuralgia

The original clinical classification scheme for trigeminal neuralgia was the delineation of Typical (Classic) TN or Atypical TN (Giovanelli, Marini, & Marossero, 1963; Hughes, 1950). Typical TN is the TN presentation best-recognized by physicians, involving brief paroxysms of severe, shock-like pain along one or more unilateral divisions of the trigeminal nerve. The pain may be triggered by light touching of the face, or by other activities such as speaking, chewing, or swallowing (other classic ones are brushing teeth or even wind blowing against face). Furthermore, neurological deficits are almost always absent, and pain-free intervals between attacks are common. In contrast, Atypical TN is used as an umbrella term to classify TN that does not fit the presentation of Typical TN. The timing may be prolonged or constant rather than paroxysmal, and the characteristics of the pain may be aching, dull, sharp, throbbing, or burning in contrast to the classic lancinating pain. The presence of neurological deficits or bilateral pain, particularly in the absence of an identifiable anatomic etiology such as compression of the trigeminal nerve root, suggests a diagnosis of Atypical TN and further workup should be considered.

Etiologic classifications of trigeminal neuralgia have additionally been created. Essential, Classical, Primary, and Idiopathic TN are terms that have been used interchangeably to describe TN due to vascular compression or an unidentifiable cause (Apfelbaum, 1977; Guidetti, 1950; Kaess, 1951; Strandjord, 1973). In contrast, Secondary and Symptomatic TN have been used synonymously to label trigeminal neuralgia caused by tumors, multiple sclerosis, or other discernable anomalies (Elster, 1951; Obrador & Boixados, 1955).