Is trigeminal neuralgia the only definitive diagnosis for pain in a tooth extraction site?

Knowing the International Classification of Orofacial Pain helps pain specialists to differentiate types of orofacial pain. It is important to select the best treatment or intervention for the patients based on the diagnosis. As part of our study, we reviewed the article published in BMC Oral Health, titled “Clinical characteristics and associated factors of trigeminal neuralgia: Experience from Addis Ababa, Ethiopia” by Ayele et al. (Ethiopia BMC Oral Health 20(1):7, 2020). For patients suffering from Classical Trigeminal Neuralgia taking a suitable dose of Carbamazepine or Gasser Ganglion radiofrequency could be helpful. Patients complaining Trigeminal neuralgia who had a history of a dental extraction in the painful region should be categorized in other group as Complex Regional Pain Syndrome type 1, who need larger dose of carbamazepine with anticonvulsant or tricyclic agent drugs (e.g. pregabalin or doxepin) or intervention (PPG radiofrequency).

Prevalence and severity of neurovascular compression in hemifacial spasm patients

Hemifacial spasm is typically caused by vascular compression of the proximal intracranial facial nerve. Although the prevalence of neurovascular compression has been investigated in a cohort of patients with classical trigeminal neuralgia, the prevalence and severity of neurovascular compression has not been well characterized in patients with hemifacial spasm. We aimed to investigate whether presence and severity of neurovascular compression are correlated to the symptomatic side in patients with hemifacial spasm. All patients in our study were evaluated by a physician who specializes in the management of cranial nerve disorders. Once hemifacial spasm was diagnosed on physical exam, the patient underwent a dedicated cranial nerve protocol magnetic resonance imaging study on a 3 T scanner. Exams were retrospectively reviewed by a neuroradiologist blinded to the symptomatic side. The presence, severity, vessel type, and location of neurovascular compression along the facial nerve was recorded. Neurovascular compression was graded as contact alone (vessel touching the facial nerve) versus deformity (indentation or deviation of the nerve by the culprit vessel). A total of 330 patients with hemifacial spasm were included. The majority (232) were female while the minority (98) were male. The average age was 55.7 years. Neurovascular compression (arterial) was identified on both the symptomatic (97.88%) and asymptomatic sides (38.79%) frequently. Neurovascular compression from an artery along the susceptible/proximal portion of the nerve was much more common on the symptomatic side (96.36%) than on the asymptomatic side (12.73%), odds ratio = 93.00, P < 0.0001. When we assessed severity of arterial compression, the more severe form of neurovascular compression, deformity, was noted on the symptomatic side (70.3%) much more frequently than on the asymptomatic side (1.82%) (odds ratio = 114.00 P < 0.0001). We conclude that neurovascular compression that results in deformity of the susceptible portion of the facial nerve is highly associated with the symptomatic side in hemifacial spasm.

The role of neurovascular conflict in the pathogenesis of classical trigeminal neuralgia and the dynamics of approaches to its visualization

The thematic review discusses various points of view on the topographic and atomic features of the location of the root of the trigeminal nerve and the superior cerebellar artery that serve as the foundation for the development of classical trigeminal neuralgia. The diagnostic capabilities of magnetic resonance imaging in the recognition of neurovascular conflict as the pathogenetic basis of the disease are considered. The search for diagnostic criteria that distinguish neurovascular conflict from neurovascular contact by improving both the performance of MRI and the new technical possibilities of its interpretation is highlighted in the chronological aspect. The possibilities of multispiral X-ray computed angiography in 3D mode as an alternative method for diagnosing neurovascular conflict are described.

Neurovascular contact plays no role in trigeminal neuralgia secondary to multiple sclerosis

Introduction A demyelinating plaque and neurovascular contact with morphological changes have both been suggested to contribute to the etiology of trigeminal neuralgia secondary to multiple sclerosis (TN-MS). The aim of this study was to confirm or refute whether neurovascular contact with morphological changes is involved in the etiology of TN-MS. Methods We prospectively enrolled consecutive TN-MS patients from the Danish Headache Center. Clinical characteristics were collected systematically. MRI scans were done using a 3.0 Tesla imager and were evaluated by the same experienced blinded neuroradiologist. Results Sixty-three patients were included. Fifty-four patients were included in the MRI analysis. There was a low prevalence of neurovascular contact with morphological changes on both the symptomatic side (6 (14%)) and the asymptomatic side (4 (9%)), p = 0.157. Demyelinating brainstem plaques along the trigeminal afferents were more prevalent on the symptomatic side compared to the asymptomatic side (31 (58%) vs. 12 (22%), p < 0.001). A demyelinating plaque was highly associated with the symptomatic side (odds ratio = 10.6, p = 0.002). Conclusion The primary cause of TN-MS is demyelination along the intrapontine trigeminal afferents. As opposed to classical trigeminal neuralgia, neurovascular contact does not play a role in the etiology of TN-MS. Microvascular decompression should generally not be offered to patients with TN-MS. The study was registered at ClinicalTrials.gov (number NCT04371575)

Application of diffusion tensor imaging in detecting microstructural alteration of the trigeminal nerve root in patients with classical trigeminal neuralgia without neurovascular compression

Background Diffusion tensor imaging (DTI) was used to detect microstructural alteration and influence of surgical intervention of the trigeminal nerve root (TR) in patients with classical trigeminal neuralgia (CTN) without neurovascular compression (woNVC) who had undergone internal neurolysis (IN). Methods Overall, 21 patients with CTN woNVC who underwent IN and 20 healthy controls were included prospectively. The differences in the means, kurtosis and skewness of each of the diffusivity metrics between the affected and unaffected nerves in patients and both nerves in controls, were then analyzed using the independent t test. Data from the affected side and the unaffected side before and 1 years after IN were compared. Results There were significantly different mean and kurtosis values for both FA and ADC of the affected side TR, compared to the unaffected side and control group respectively before IN. 1 year after surgery, most of these differences significantly reduced in comparison between the affected side and unaffected side, the affected side and control group, and these trends were also in accordance with the relief of pain. The Pearson correlation coefficient showed a strong negative correlation between decrease of ADC in the affected side compared to the surgical outcome in BNI total score. Conclusions The changes of diffusive property of TR could explain the efficiency of IN. The pretreatment DTI metrics could be an effective prognostic factor for providing potential noninvasive, brain-based biomarkers to support an optimal treatment selection for individual patients with CTN woNVC.