Cannabinoid Therapy for Refractory Trigeminal Neuropathic Pain: Quantification of Somatosensory Alterations (QualST)...

Trigeminal neuropathic pain (TNP) is a chronic and debilitating condition frequently resistant to conventional pharmacological therapies. Although cannabinoids have emerged as a potential adjunctive treatment, objective clinical documentation of their effects in orofacial neuropathic pain remains limited.

We report two female patients with refractory TNP-one post-traumatic and one idiopathic-who experienced insufficient relief despite trials of anticonvulsants, antidepressants, topical agents, and local interventions. Both patients received a balanced tetrahydrocannabinol (THC):cannabidiol (CBD) sublingual formulation (20 mg/mL each) following a structured titration protocol and were monitored over 8 weeks. Outcomes were assessed using the Douleur Neuropathique 4 Questions (DN4), the visual analog scale (VAS), the World Health Organization Quality of Life-BREF (WHOQOL-Bref), and qualitative sensory testing (QualST). Additionally, three-dimensional facial stereophotogrammetry was employed to objectively quantify areas of hyperfunction and allodynia. Treatment resulted in a marked analgesic response (VAS reduction from 9 to 4 and from 10 to 2), qualitative changes in pain phenotype-from shock-like to predominantly burning-and functional improvement in mastication and oral hygiene. Stereophotogrammetry demonstrated a substantial reduction in sensitized regions, with extraoral hyperfunctional area decreasing from 113.72 to 27.54 cm² and complete resolution of allodynia by week 8. WHOQOL-Bref scores improved in both patients, with physical domain scores increasing from 50.0 to 60.7 and from 25.0 to 39.3, accompanied by gains in psychological well-being. No serious adverse events were recorded.

These cases illustrate the potential clinical relevance of cannabinoids as an adjunctive approach for refractory TNP and highlight the importance of multidimensional assessment strategies. The findings should be interpreted cautiously given the descriptive nature of case reports; however, they underscore the need for controlled studies to further investigate the efficacy and safety of cannabinoid-based therapies in orofacial neuropathic pain.