Recommandations pour le diagnostic et la prise en charge de la névralgie trigéminale classique

The correlation study between posterior fossa crowding and classical trigeminal neuralgia

OBJECTIVE

To explore the correlation between posterior fossa crowding and the occurrence of classical trigeminal neuralgia (TN).

METHODS

A total of 60 patients diagnosed with classical TN and 60 age- and sex-matched healthy volunteers were included as a control group for a case-control study. All subjects underwent high-resolution 3D magnetic resonance imaging (MRI) examinations (including 3D-FIESTA and 3D-TOF MRA sequences). The original data were subjected to 3D reconstruction and measurement of posterior fossa volume (PFV) and hindbrain volume (HBV) using 3D-slicer software. The posterior fossa crowding index (PFCI) was calculated as HBV/PFV × 100%. Finally, data were analyzed using SPSS 22.0 statistical software.

RESULTS

The average PFCI in patients with TN was 85.0% ± 3.9%, compared to 82.7% ± 3.9% in the control group, with a significant statistical difference (P = 0.025). Female patients with TN had a more crowded posterior fossa than male patients (86.4% ± 3.8% vs. 83.4% ± 3.4%, P = 0.033). Multiple linear regression analysis showed that a higher PFCI was associated with being female (P = 0.022), younger age (P = - 0.003), and being a patient with TN (P = - 0.023).

CONCLUSION

Patients with PTN have a more crowded posterior fossa compared to the healthy control group. A higher PFCI is associated with being female, younger age, and being a patient with TN. Posterior fossa crowding may be a risk factor for neurovascular conflict (NVC), making it more likely to lead to the occurrence of TN.

"Status trigeminal neuralgia": Analysis of 39 cases and proposal for diagnostic criteria

OBJECTIVE

The aim of this descriptive study was to propose diagnostic criteria for acute exacerbation of trigeminal neuralgia (TN) based on the analysis of retrospective cases.

BACKGROUND

TN is a rare and extremely painful condition whose evolution can be punctuated by major exacerbations, leading to significant functional impairment. Several denominations are used for these exacerbations: "acute exacerbation", "status of trigeminal neuralgia", and "status trigeminus". There is currently no clinical definition of this state. In this manuscript, we used the term "status trigeminal neuralgia" (STN).

METHODS

We conducted a retrospective study, in a tertiary care specialist headache center, in France. Patients were selected from January 2015 to October 2022, with the French translation of the keyword "STN", in the medical records (outpatients) or the codage for trigeminal neuralgia (inpatients). Additional cases of STN were prospectively recruited from October 2022 to February 2023. We analyzed the clinical and paraclinical data of these patients.

RESULTS

Thirty-nine patients presenting with STN were included. There was a preponderance of women (64%) with 24 cases of classic TN (62%) and 15 cases of secondary TN (38%). Concerning STN, 39 episodes were described. Pain was very severe in all patients. Cranial autonomic signs were present in 23% of cases. Pain extended beyond the usual territory in 44% of cases. A continuous pain background was present in 35% of cases. With regard to triggering factors, paroxysms of facial pain were triggered by eating (97% of patients), speaking (90%) or drinking (62% of patients). Repercussions on weight, hydration, or mood disorders were observed in 67%, 56% and 59% of the cases, respectively.

CONCLUSION

STN is a rare clinical presentation of TN. We proposed criteria and a new denomination for this condition.

[Frameless trigeminal neuralgia radiosurgery with a dedicated linear accelerator: From equipment commissioning to initial clinical results]

PURPOSE

Radiosurgery for the treatment of trigeminal neuralgia delivers a very high dose in a single fraction, over a few millimeters, at a single isocenter placed along the nerve. We present here the different steps that have been performed to validate small beams by conical collimators, and report the clinical results of the first patients treated on Novalis Tx®, frameless.

MATERIAL AND METHODS

First, the geometric accuracy of 4 and 6mm conical collimators was evaluated using Winston-Lutz tests; then dosimetric data acquisition was performed using high spatial resolution detectors (PTW 60019 microdiamond and a PTW 60017 E-diode). The corrective factors of the TRS 483 report were applied to calculate the collimator aperture factors. These dosimetric data were then compared with the data implemented in the iPlan® treatment planning system. Then end-to-end tests were performed to control the entire treatment process using an anthropomorphic phantom "STEEV". Between 2020 and 2022, 18 patients were treated for refractory trigeminal neuralgia on Novalis Tx®, frameless, with Exactrac® repositioning. A total of 17 patients were evaluated (one was lost to follow-up) using the BNI score for pain assessment and MRI with a median follow-up of 12 months.

RESULTS

The quality criteria of geometric and dosimetric accuracy were met for the 6-mm cone but not for the 4-mm cone. All patients were treated with a 6-mm cone with a dose of 90Gy prescribed at the isocenter at the root entry zone. Initial pain control was obtained in 70.5% of our patients, and 53% maintained pain control with a median follow-up of 12 months. All recurrences occurred within 3 to 6 months after radiosurgery. No brainstem toxicity was observed. Six patients had non-disabling facial hypoesthesia, half of whom already had pretreatment hypoesthesia.

CONCLUSION

The treatment of trigeminal neuralgia on a dedicated linear accelerator is a highly technical treatment whose accuracy and safety are paramount. The physical measurements allowed the commissioning of the technique with a 6mm cone. Our first clinical results are in accordance with the literature.

Multivariate models to predict pain recurrence and sensitive complications after percutaneous balloon compression in trigeminal neuralgia

OBJECTIVE

Percutaneous balloon compression (PBC) is a popular treatment option for trigeminal neuralgia. However, the efficacy of PBC is widely considered to be associated with the occurrence of sensitive complications, although neither this correlation nor the underlying mechanisms have been established. The objectives of the present study were to identify factors predicting time to pain recurrence after PBC and identify factors predicting a severe sensitive complication.

METHODS

The authors conducted a retrospective study on patients who underwent PBC for the first time between 1985 and 2019 in two French hospitals. Data were retrieved from patients' medical records. Potential clinical and radiological predictors for time to pain recurrence and severe sensitive complication were evaluated using a Cox model and a logistic regression, respectively.

RESULTS

A total of 131 patients were included in the study, with a median follow-up of 3.0 years. Pain recurrence occurred in 77 patients, and the median time to pain recurrence was 2.0 years. In the multivariate analysis, six independent factors predicting pain recurrence were identified: 1) longer duration of presurgical symptoms; 2) localization of the pain along the mandibular branch of the trigeminal nerve (V3); 3) atypical pain; 4) diagnosis of multiple sclerosis; 5) use of a medical device not specifically adapted for trigeminal neuralgia surgery; and 6) duration of balloon compression > 60 seconds. Regarding the secondary objective, 26 patients presented a severe sensitive complication after PBC, which the authors defined as the development of a new sensitivity disorder of the cornea, deafferentation pain known as anesthesia dolorosa, and/or long-lasting hypoesthesia augmentation characterized by the new appearance or increase in size or intensity of an area of hypoesthesia in the face for at least 3 months. The only predictor associated with a severe sensitive complication in the multivariate analysis was compression duration > 60 seconds.

CONCLUSIONS

These results show that the risk of postoperative complications can be assessed at the patient level, the most important modifiable parameter being the time of compression by the balloon. Although this study shows the relevance of a personalized medicine approach, its clinical application remains to be validated.

[Stereotactic radiotherapy of non-tumoral brain pathologies: Arteriovenous malformations and trigeminal neuralgias]

Stereotactic radiotherapy and radiosurgery allow delivery of high irradiation doses in a limited volume. These techniques are specially adapted to brain and nervous pathologies. Indication are not only cancers and tumors but also non tumor tissues such as arteriovenous malformations. In some case purpose of stereotactic radiotherapy is solely functional, for example for trigeminal neuralgia. We detail the questions that raise treatment of these non-tumor pathologies. These pathologies imply a multidisciplinary approach that associate radiation oncologists, neuro-radiologist and neurosurgeons.

Is this really trigeminal neuralgia? Diagnostic re-evaluation of patients referred for neurosurgery

OBJECTIVES

Patients with facial pain are sometimes referred for neurosurgical treatment with a poorly documented diagnosis of trigeminal neuralgia. In such cases, neurosurgery will usually not be helpful. We conducted a re-evaluation of the diagnosis in patients referred for neurosurgical treatment of presumed trigeminal neuralgia. Our objective was to find out why and how often misdiagnosis occurred.

METHODS

A retrospective study was done in consecutive first-time patients referred for trigeminal neuralgia to our outpatient clinic in 2019. We used five ICHD-3-based clinical criteria to verify or exclude the diagnosis. In patients where trigeminal neuralgia was excluded, we established a diagnosis for their facial pain based upon medical history and a physical examination by a neurosurgeon - often supplemented with examination by an oral surgeon.

RESULTS

Thirty-eight patients were referred for presumed trigeminal neuralgia. Only 17 of them fulfilled the five criteria and were diagnosed with trigeminal neuralgia. In 20 of the remaining 21 patients trigeminal neuralgia could be clearly excluded, while one of the patients had a periodontitis closely mimicking trigeminal neuralgia. In 14 of the 21 patients we diagnosed temporomandibular dysfunction or dental conditions. MRI scans had detected low-grade neurovascular contacts in 13 of the 21 patients, a finding that was clearly overestimated by the referring neurologists in seven patients.

CONCLUSIONS

Overdiagnosis of trigeminal neuralgia was common in patients referred for neurosurgery, mostly due to insufficient clinical evaluation combined with an overestimation of MRI-detected NVCs. The clinical diagnosis should be critically re-evaluated before recommending neurosurgery to patients referred for presumed trigeminal neuralgia.