Clinical Features of Peripheral Painful Traumatic Trigeminal (Orofacial) Neuropathy

Objectives: Pain due to traumatic nerve injury in the trigeminal region has been poorly defined. Our aim was to describe the clinical presentation of painful traumatic trigeminal neuropathy (PTTN). Methods: Included were patients with a complaint of persistent (>3 months) orofacial pain with a traumatic neuropathic etiology, presenting at an Orofacial Pain Clinic. Results: Of the 91 PTTN cases, initiating event was macrotrauma in 26.4% (19 traffic accidents, 5 physical assaults) and invasive dentistry in 73.6% (21 extractions, 16 implantations, 15 endodontic/periodontal surgeries, 11 non-surgical endodontics). The areas affected were the mandible (31.9%), maxilla (29.6%), and exclusively intraoral (19.8%), and in 9.9% was bilateral. Pain intensity was 7.7±1.8 (0-to-10 scale), with no difference between dental and macrotrauma groups. Thirty-nine patients reported a predominantly continuous pain, 30 –paroxysmal (9±11.4 minutes of attack duration) and 22 –episodic (3.1±2.1 hours, 4 attacks/week). Trigger points were found in 5.5%; 11% reported accompanying autonomic signs; and 37.4% were woken from sleep because of pain. Hypoalgesia with/without allodynia occurred in 23.1%, and 30.8% respectively; hyperalgesia with/without allodynia in 9.9% and 7.7%, respectively; and allodynia alone in 24.2%. Electrical threshold ratios for affected-to-unaffected regions: Aß (2.3±1.7), A∂ (2.6±2.3) and C-Fibers (2.6±1.8) were higher than the expected 1 (p<0.05). Many patients were lost to follow-up (36.3%) or did not respond to therapy (24.2%). Total pain relief was obtained in 7.7%. Conclusions: PTTN has a unique clinical profile that differs from other neuropathies. The collected data will allow the further validation of the proposed criteria at a later stage.