A New Classification for Facial Pain

PURPOSE: A patient-oriented classification scheme for facial pains commonly encountered in neurosurgical practice is proposed. CONCEPT: This classification is driven principally by the patient's history. RATIONALE: The scheme incorporates descriptions for so-called "atypical" trigeminal neuralgias and facial pains but minimizes the pejorative, accepting that the physiology of neuropathic pains could reasonably encompass a variety of pain sensations, both episodic and constant. Seven diagnostic labels result: trigeminal neuralgia Types 1 and 2 refer to patients with the spontaneous onset of facial pain and either predominant episodic or constant pain, respectively. Trigeminal neuropathic pain results from unintentional injury to the trigeminal nerve from trauma or surgery, whereas trigeminal deafferentation pain results from injury to the nerve by peripheral nerve ablation, gangliolysis, or rhizotomy in an intentional attempt to treat either trigeminal neuralgia or other facial pain. Postherpetic neuralgia follows a cutaneous herpes zoster outbreak (shingles) in the trigeminal distribution, and symptomatic trigeminal neuralgia results from multiple sclerosis. The final category, atypical facial pain, is synonymous with facial pain secondary to a somatoform pain disorder. Atypical facial pain can be suspected but not diagnosed by history and can be diagnosed only with detailed and objective psychological testing. CONCLUSION: This diagnostic classification would allow more rigorous and objective natural history and outcome studies of facial pain in the future.