This current case is the first report of severe unilateral (left-sided) post-traumatic trigeminal neuropathic pain involving all branches of the trigeminal nerve after custom-made total temporomandibular joint replacement (TMJR). After a bilateral TMJR procedure a, 43-year old female patient complained of left-sided lingual and mental nerve hypoesthesia. In the following months, the patient developed unsustainable neuropathic pain at the area of cutaneous distribution of the mental (V 3 ) and infraorbital (V 2 ) nerves combined with hypoesthesia in all trigeminal divisions. Neurosensory deficits in V 1-3 were confirmed by quantitative sensory testing and electrophysiological studies. Treatments consisted of anti-depressants, anti-epileptics, opioids and eventually radiofrequent ablation of the peripheral branches without notable improvement in pain complaints or sensory deficits. The current case warrants temporomandibular joint surgeons for the possible risk of post-traumatic trigeminal neuropathic pain.
Trigeminal neuropathic pain may follow temporomandibular joint replacement.
Symptoms may spread far beyond the affected dermatome on the basis of an inflammatory and/or excitotoxic response.
Quality of life deteriorates with persistent neuropathic pain.
Conservative treatment is disappointing.
A multidisciplinary approach with thorough investigation is advised.
In the current article, a case of progressive severe post-traumatic trigeminal neuropathic pain after a custom-made total temporomandibular joint replacement (TMJR) is reported. Current literature on TMJR shows variable postoperative neurosensory deficits, which are almost all temporary in nature and none reporting neuropathic pain. Therefore, the present case presentation is of major importance to oral and maxillofacial surgeons involved in TMJR. Awareness should be raised on the possible TMJR complications.
Presentation of case
A 43-year old female with an unremarkable medical history was referred in February 2019 to the Department of Oral & Maxillofacial Surgery, University Hospitals Leuven, to evaluate trigeminal nerve sensory function after undergoing a custom-made TMJR of both joints in November 2018. The initial indication for TMJR was the bilateral internal TMJ derangement of the TMJ (Wilkes classification V) with pain and limited mouth opening of 18 mm, unresponsive to conservative treatment (education, physiotherapy and splint therapy). Immediately after TMJR surgery the patient reported left-sided hypoesthesia in the area of distribution of the lingual and mental nerves. Interincisal maximal mouth opening improved to 25 mm postoperative. A couple of days later, the patient developed shooting electric-like sensations in both the chin and tongue area for which she received pregabalin 75 mg 3 times daily. On a follow-up, four months after the TMJR procedure, she complained of mild shooting pains in the left mental region. Psychological and pain questionnaires showed moderate pain scores of 5 out of 10 on a visual analog scale (VAS), without severe psychological impact ( Table 1 ). Quantitative sensory testing (QST) confirmed hypoesthesia of both lingual and mental area with thermal allodynia ( Table 2 ). In the next two months during follow-up consultations, the patient reported progressive hypoesthesia with mechanical and thermal allodynia of V 2 (area of distribution of the infraorbital nerve) and after V 1 (area of distribution of the supraorbital nerve) trigeminal division which was again confirmed on QST ( Table 2 ). Corneal reflex was absent on the left side. Additionally, the patient developed left hemifacial untenable neuropathic pain, scoring 10 out of 10 on a VAS scale, in V 3 and V 2 . Due to the severity of her complaints and progressiveness further investigations were performed. Electromyography revealed severe motor axonal loss of the left masseter muscle. Conduction studies between the mental and oval foramina [ ] showed no response, arguing for a severe traumatic injury at the level or just below the foramen ovale. Infra-orbital (V2) and supra-orbital (V1) stem reflexes were unremarkable, indicating intact V1-V2 branches. Cone beam computed tomography (CBCT) and panoramic radiograph showed well positioned bilateral TMJ prostheses ( Fig. 1 ). Magnetic resonance neurography revealed hypertrophy of the left masseteric nerve and increased signal intensities of the inferior alveolar and lingual nerve ( Fig. 1 ). Due to metallic artifacts nerve continuity could not be assessed on magnetic resonance neurography. No intracranial abnormalities were noted. The diagnosis was made of progressive post-traumatic trigeminal neuropathic pain. After multidisciplinary discussion and due to the risk of prosthesis surinfection, a conservative approach was advised, and the patient was referred back to her treating physician. Medications included amitriptyline, pregabalin and tramadol with limited pain control. In the following year, she was treated with radiofrequent ablation of V 2 , V 3 , C 3 and the Gasserian ganglion during multiple sessions with neuropathic pain improvement in V 2 but not in V 3 . Twenty sessions of repetitive transcranial magnetic stimulation had no impact on the pain complaints. The patient is currently scheduled for a consultation to evaluate if she qualifies for thalamic deep brain stimulation. Follow-up questionnaires a year after initial TMJR surgery showed a major impact on quality of life and psychosocial measures ( Table 1 ).
|EuroQoL-5||Lower value indicates better QoL for subdomain|
|EQ5D Usual activities||0–4||0||3|
|EQ5D Pain – Discomfort||0–4||3||3|
|EQ5D Anxiety – Depression||0–4||0||1|
|EQ5D VAS score on overall health condition||Higher value indicates better QoL||0–100||72||40|
|Central sensitization inventory||<40 means unlikely for centralization phenomenon||0–100||39||39|
|Brief Pain Inventory||Lower values indicate better QoL and lower pain|
|Maximum pain score||0–10||6||8|
|Minimum pain score||0–10||2||1|
|Mean pain score||0–10||4||5|
|Pain score now||0–10||5||6|
|Pain catastrophizing scale||<20||0–52||15||26|
|Pain vigilance and awareness questionnaire||<40||0–80||23||39|