Classical Trigeminal Neuralgia Research Articles

Prevalence of classical trigeminal neuralgia: current state of the problem in the Rostov region

<h3>ЦЕЛЬ ИССЛЕДОВАНИЯ</h3> Популяционные исследования распространенности невралгии тройничного нерва (НТН) во всем мире редки, а в масштабах Ростовской области (РО) неизвестны. Целью данного исследования является определение распространенности НТН в РО. <h3>МАТЕРИАЛ И МЕТОДЫ</h3> Изучено 368 историй болезни пациентов с установленным диагнозом НТН, проходивших обследование и лечение в клинике РостГМУ за период с 1994 по 2020 г. Необходимый для расчетов материал взят с сайтов Единой межведомственной информационно-статистической системы (ЕМИСС), Росстата и из ряда статистических сборников. <h3>РЕЗУЛЬТАТЫ</h3> Среднегодовой показатель распространенности классической НТН у населения РО за изучаемый период составил 8,5 (95% ДИ 7,64—9,49) случая на 100 тыс. населения. Возраст дебюта заболевания по медиане составил 55 лет (95% ДИ 53,5—56,5 года). В гендерном отношении — 262 (71%) женщины и 106 (29%) мужчин. При этом соотношение мужчин и женщин среди как городского, так и сельского населения составило 1:2. Общая заболеваемость НТН выше среди городского населения, она составила 9,5 (95% ДИ 8,5—10,9) на 100 тыс. населения РО, сельского населения — 6,5 (95% ДИ 5,1—7,98) на 100 тыс. населения РО при уровне значимости &lt;0,00001. Распространенность классической НТН среди женщин статистически значимо выше, она составила 11,0 (95% ДИ 9,68—12,21) против 5,5 (95% ДИ 4,66—6,74) среди мужчин. Среди городского населения наибольший показатель распространенности НТН (13,8 на 100 тыс. населения) в городах, имеющих максимально высокий уровень загрязнения (концентрации отдельных вредных веществ в 5 раз превышают допустимые нормы!). Со средним значением экологической ситуации частота случаев НТН составляла 4,2% (95% ДИ 1,5—9,7%). Заболеваемость классической НТН у городского населения РО статистически значимо выше, чем у сельского, что также коррелирует со степенью напряженности экологической обстановки в регионах.

Familial occurrence of classical and idiopathic trigeminal neuralgia

Trigeminal neuralgia (TN) is a severe facial pain disease with unknown pathogenesis. It has been thought that the familial form of TN is rare with a prevalence of about 1–2% among affected individuals, but emerging evidence suggests a role of genetic factors. This study examined the occurrence of familial TN among patients with classical or idiopathic TN. Patients with TN recruited from a hospital registry received an informed consent form with a questionnaire, and individuals reporting other family members with TN underwent a structured phone-interview. For affected family members, type of TN, available clinical, imaging, management results and available hospital patient records were studied. Pedigrees for all affected families were established. This study included 268 patients with either classical or idiopathic TN. The familial form of TN was present in 41/268 (15.3%) patients, that is, 37/244 (15.2%) patients with classical TN and in 4/24 (16.7%) with idiopathic TN. Total 38 families were identified, with two affected members in 32/38 families (84.2%), three affected family members in 5/38 (13.2%) and four family members in 1/38 (2.6%) families. Comparing the 41 familial TN cases with the 227 sporadic TN patients showed significantly earlier onset of TN and a significantly higher occurrence of right-sided pain in familial cases, while there was no difference in gender distribution, occurrence of arterial hypertension or trigeminal branch involved. Among patients with classical or idiopathic TN, the occurrence of the familial form of the disease is more frequent than traditionally assumed.

Altered brain functional network dynamics in classic trigeminal neuralgia: a resting-state functional magnetic resonance imaging study

BackgroundAccumulating studies have indicated a wide range of brain alterations with respect to the structure and function of classic trigeminal neuralgia (CTN). Given the dynamic nature of pain experience, the exploration of temporal fluctuations in interregional activity covariance may enhance the understanding of pain processes in the brain. The present study aimed to characterize the temporal features of functional connectivity (FC) states as well as topological alteration in CTN.MethodsResting-state functional magnetic resonance imaging and three-dimensional T1-weighted images were obtained from 41 CTN patients and 43 matched healthy controls (HCs). After group independent component analysis, sliding window based dynamic functional network connectivity (dFNC) analysis was applied to investigate specific FC states and related temporal properties. Then, the dynamics of the whole brain topological organization were estimated by calculating the coefficient of variation of graph-theoretical properties. Further correlation analyses were performed between all these measurements and clinical data.ResultsTwo distinct states were identified. Of these, the state 2, characterized by complicated coupling between default mode network (DMN) and cognitive control network (CC) and tight connections within DMN, was expressed more in CTN patients and presented as increased fractional windows and dwell time. Moreover, patients switched less frequently between states than HCs. Regarding the dynamic topological analysis, disruptions in global graph-theoretical properties (including network efficiency and small-worldness) were observed in patients, coupled with decreased variability in nodal efficiency of anterior cingulate cortex (ACC) in the salience network (SN) and the thalamus and caudate nucleus in the subcortical network (SC). The variation of topological properties showed negative correlation with disease duration and attack frequency.ConclusionsThe present study indicated disrupted flexibility of brain topological organization under persistent noxious stimulation and further highlighted the important role of “dynamic pain connectome” regions (including DMN/CC/SN) in the pathophysiology of CTN from the temporal fluctuation aspect. Additionally, the findings provided supplementary evidence for current knowledge about the aberrant cortical-subcortical interaction in pain development.

A.2 Clinical application of T1-w/T2-w ratio images for in vivo comparisons of myelin content in patients with trigeminal neuralgia

Background: Novel magnetic resonance (MR) imaging techniques prompted the emergence of T1-w/T2-w images or “myelin-sensitive maps (MMs)” to measure myelin in vivo. However, acquisition-related variations in MR intensities prevent meaningful quantitative comparisons between MMs. We propose an improved pipeline to standardize MMs that is applied to patients with classic trigeminal neuralgia (CTN) and trigeminal neuralgia secondary to multiple sclerosis (MSTN). Methods: 3T scanner was used to obtain T1-w and T2-w images for 17 CTN and 17 MSTN patients. Template images were obtained from ICBM152 database. MS plaques and normal-appearing white matter (NAWM) were labelled. A Gaussian curve-fit was applied to the histogram of the intensity distribution of each patient image, and transformed to match the Gaussian curve-fit of the template image. Results: MM intensities were decreased within MS plaques, compared to NAWM in MSTN patients (p&lt;0.001) and its corresponding regions in CTN patients (p&lt;0.001). Qualitatively, the standardized patient image and its histogram better resembled the ICBM152 template. Conclusions: MM analysis revealed reduced myelin content in MS plaques compared to corresponding regions in CTN patients and surrounding NAWM in MSTN patients. The standardized MM serves as a non-invasive, clinical tool for quantitative analyses of myelin content between different brain regions and different patients in vivo.

Radiofrequency thermocoagulation for the treatment of trigeminal neuralgia.

Although microvascular decompression (MVD) should be considered as the first-line treatment for classic trigeminal neuralgia (TN) owing to neurovascular compression of the trigeminal nerve, an increasing number of surgeons prefer radiofrequency thermocoagulation (RFT). RFT is a Gasserian ganglion-level ablative intervention that may achieve immediate pain relief for TN. It is used for emergency management when MVD is not suitable for the patient. As the gold surgical standard of classic trigeminal neuralgia, MVD has the advantage of longer efficacy. However, there are currently no high-quality controlled trials to evaluate the efficacy of MVD and RFT. For the present systematic review, the PubMed, Embase and Cochrane databases (all entries up until July 31, 2020) were searched to identify studies related to RFT in order to provide valuable information for clinical decision-making. The efficacy of the RFT method was evaluated in terms of the initial pain relief percentage, recurrence rate and follow-up time. Furthermore, the incidence rate of various postoperative complications was retrieved. RFT was used for a wider range of applications than MVD, including use for primary (owing to neurovascular compression of the trigeminal nerve), idiopathic and secondary (due to primary neurological diseases) TN, and provided a high rate of initial pain relief and long-term pain control. Although this method has several side effects, the incidence of complications could be reduced by precise cannulation. Furthermore, the complications that occurred were not permanent. Thus, RFT is a safe and effective minimally invasive method of pain relief for patients with TN.

Microvascular decompression in trigeminal neuralgia: predictors of pain relief, complication avoidance, and lessons learned

ObjectiveTo analyze characteristics associated with long-term pain relief after microvascular decompression (MVD) for trigeminal neuralgia (TGN). Description of associated morbidity and complication avoidance.MethodsOne hundred sixty-five patients with TGN underwent 171 MVD surgeries at the authors’ institution. Patient characteristics and magnetic resonance imaging (MRI) datasets were obtained through the hospital’s archiving system. Patients provided information about pre- and post-operative pain characteristics and neurologic outcome. Favorable outcome was defined as a Barrow Neurological Institute (BNI) pain intensity score of I to III with post-operative improvement of I grade.ResultsType of TGN pain with purely paroxysmal pain (p = 0.0202*) and TGN classification with classical TGN (p = 0.0372*) were the only significant predictors for long-term pain relief. Immediate pain relief occurred in 90.6% of patients with a recurrence rate of 39.4% after 3.5 ± 4.6 years. MRI reporting of a neurovascular conflict had a low negative predictive value of 39.6%. Mortality was 0% with major complications observed in 8.2% of patients. Older age was associated with lower complication rates (p = 0.0009***). Re-MVD surgeries showed improved long-term pain relief in four out of five cases.ConclusionsMVD is a safe and effective procedure even in the elderly. It has the unique potential to cure TGN if performed on a regular basis, and if key surgical steps are respected. Early MVD should be offered in case of medical treatment failure and paroxysmal pain symptoms. The presence of a neurovascular conflict on MRI is not mandatory. In case of recurrence, re-MVD is a good treatment option that should be discussed with patients.Highlights• Long-term analysis of pain relief after MVD.• Positive predictors for outcome: classical TGN and purely paroxysmal pain.• Presence of neurovascular conflict in MRI is not mandatory for MVD surgery.• Analysis of complications and surgical nuances for avoidance.• MVD is a safe procedure also in the elderly.

Historical aspects of the problem of treatment of trigeminal neuralgia and the role of neurosurgical methods in its solution (literature review)

The trigeminal nerve is a mixed fifth cranial nerve, consisting of motor and sensory components. The sensitive component receives somesthetic information from the skin and mucous membranes of the face into the central nervous system, and the motor component is responsible for the innervation of chewing muscles. One of the manifestations of the pathology of the trigeminal nerve is pain syndrome. Trigeminal neuralgia occupies the main place among neurogenic pain syndrome in the face, is characterized by а severe course and the absence of sufficiently effective methods of treatment. According to the World Health Organization (WHO), the prevalence of trigeminal neuralgia in different countries is 2–5 cases per 100 thousand people per year. Trigeminal neuralgia is classified into 3 etiologic categories. Idiopathic trigeminal neuralgia occurs without apparent cause. Classical trigeminal neuralgia is caused by vascular compression of the trigeminal nerve root. Secondary trigeminal neuralgia is the consequence of a major neurologic disease, e. g., a tumor of the cеrеbеllоpоntine angle or multiple sclerosis. Today, there are many different options for the surgical treatment of trigeminal neuralgia. microvascular decompression of the root, radiosurgical destruction of the Gasser’s node, radiofrequency destruction, glycerol rhizotomy, balloon microcompression are considered the main effective and proven surgical methods for treating trigeminal neuralgia. But the questions of diagnosing the cause of the disease and choosing an adequate surgical method for treating therapeutically resistant trigeminal neuralgia for a particular patient remain open. The development of surgical methods begins from ancient times to the present day. The main stages in the development of neurosurgical treatment methods are presented. The following surgical techniques are described: open method – microvascular decompression, and closed percutaneous destructive methods – radiofrequency destruction, glycerol rhizotomy, balloon compression, radiosurgery, cryodestruction, laser destruction, botulinum toxin injections.

Pre-operative Limbic System Functional Connectivity Distinguishes Responders From Non-responders to Surgical Treatment for Trigeminal Neuralgia.

Background: Trigeminal neuralgia (TN) is a severe facial pain condition often requiring surgical treatment. Unfortunately, even technically successful surgery fails to achieve durable pain relief in many patients. The purpose of this study was to use resting-state functional magnetic resonance imaging (fMRI) to: (1) compare functional connectivity between limbic and accessory sensory networks in TN patients vs. healthy controls; and (2) determine if pre-operative variability in these networks can distinguish responders and non-responders to surgery for TN.Methods: We prospectively recruited 22 medically refractory classic or idiopathic TN patients undergoing surgical treatment over a 3-year period, and 19 age- and sex-matched healthy control subjects. fMRI was acquired within the month prior to surgery for all TN patients and at any time during the study period for controls. Functional connectivity analysis was restricted to six pain-relevant brain regions selected a priori: anterior cingulate cortex (ACC), posterior cingulate cortex, hippocampus, amygdala, thalamus, and insula. Two comparisons were performed: (1) TN vs. controls; and (2) responders vs. non-responders to surgical treatment for TN. Functional connectivity was assessed with a two-sample t-test, using a statistical significance threshold of p < 0.050 with false discovery rate (FDR) correction for multiple comparisons.Results: Pre-operative functional connectivity was increased in TN patients compared to controls between the right insular cortex and both the left thalamus [t(39) = 3.67, p = 0.0007] and right thalamus [t(39) = 3.22, p = 0.0026]. TN patients who were non-responders to surgery displayed increased functional connectivity between limbic structures, including between the left and right hippocampus [t(18) = 2.85, p = 0.0106], and decreased functional connectivity between the ACC and both the left amygdala [t(18) = 2.94, p = 0.0087] and right hippocampus [t(18) = 3.20, p = 0.0049]. Across all TN patients, duration of illness was negatively correlated with connectivity between the ACC and left amygdala (r2 = 0.34, p = 0.00437) as well as the ACC and right hippocampus (r2 = 0.21, p = 0.0318).Conclusions: TN patients show significant functional connectivity abnormalities in sensory-salience regions. However, variations in the strength of functional connectivity in limbic networks may explain why some TN patients fail to respond adequately to surgery.

The Central Response of Electroacupuncture on Trigeminal Neuralgia Based on Resting-State Functional Magnetic Resonance Imaging: A Protocol for a Pre-Experimental, Single-Centre, Randomized, Controlled Trial.

ObjectiveTo verify the efficacy of electroacupuncture (EA) on classical trigeminal neuralgia (CTN), and to observe the brain functional status of patients with CTN and the intervention effects of EA on brain function by resting-state functional magnetic resonance imaging (rs-fMRI).Methods and AnalysisThirty CTN patients will be randomly divided into EA combined with carbamazepine group and carbamazepine group in 2:1 ratio by using a random number table. Patients in EA combined with carbamazepine will receive EA treatment and carbamazepine for four weeks. The carbamazepine group will only receive carbamazepine treatment. VAS (visual analogue scale), HAMA (Hamilton Anxiety Scale), HAMD (Hamilton Depression Scale) and SF-36 (short form 36 health survey) will be performed before, after four-week treatments and at three-month follow-up in CTN patients. Six CTN patients will be randomly selected from EA combined with carbamazepine group and carbamazepine group, respectively, before treatment, and twelve paired healthy participants will be recruited at the same time. The twelve CTN patients will be scanned by rs-fMRI before and after treatment, and the healthy participants will be scanned by rs-fMRI only at baseline. Regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) analysis will be carried out to compare the dysfunctional brain regions between CTN patients and healthy participants, as well as the differences between two groups of patients with CTN after treatment.Trial RegistrationChiCTR-1900027873.

White matter integrity in patients with classic trigeminal neuralgia: a multi-node automated fiber tract quantification study.

ObjectiveTo study the characteristics of point-by-point destruction of white matter tracts in patients using automated fiber tract quantification (AFQ).MethodsThirty-four classic trigeminal neuralgia (CTN) patients and 34 healthy control (HC) subjects underwent 3.0 T diffusion tensor magnetic resonance imaging and T1-weighted imaging. The fractional anisotropy (FA) and mean diffusivity (MD) of 100 nodes of 20 fiber tracts were analyzed by AFQ, and the correlations of the FA and MD with the visual analogue scale (VAS) pain score were assessed.ResultsThe FA values of the left thalamic radiation (middle segment), left corticospinal tract, callosum forceps minor, and right uncinate fasciculus were significantly lower in CTN patients than in the HC group. The MD of the left thalamic tract (middle segment), left corticospinal tract, right superior longitudinal fasciculus, and left superior longitudinal fasciculus (anterior segment) were significantly higher in the CTN group. Additionally, the VAS pain score in CTN patients was positively correlated with FA and negatively correlated with MD.ConclusionSpecific fiber tract nodes were damaged in CTN patients, which was related to the VAS pain score. Multi-node quantitative studies of fiber tract damage are valuable for understanding the white matter tract damage pattern in CTN patients.

Vascular compression in trigeminal neuralgia discloses trigeminal root somatotopic organization

In Trigeminal Neuralgia (TN) pain is localized in the distribution of one or more branches of the trigeminal nerve. A hallmark of TN is the presence of discrete skin areas able to trigger pain attacks when touched. In classical TN trigeminal reflexes are normal but dedicated MRI studies can recognize a vascular compression with morphological changes of trigeminal root. In this combined clinical, neuroimaging and neurophysiological study we aim to disclose trigeminal root somatotopic organization.

Alterations of brain structural MRI are associated with outcome of surgical treatment in trigeminal neuralgia.

To assess magnetic resonance imaging (MRI) alterations occurring in patients with trigeminal neuralgia (TN) and to explore the predictive ability of MRI for initial surgical outcome and long-term pain relief/recurrence after Gamma Knife radiosurgery (GKS). Thirty patients with idiopathic or classic TN, who underwent GKS and were followed for at least 24months, were retrospectively included. Pre-treatment structural MRI and pre- and serial, postoperative clinical features were investigated. Fifteen age- and sex-matched healthy controls were also enrolled. Cortical thickness and gray matter (GM) volumes were assessed in TN patients relative to controls, as well as between patient subgroups according to treatment outcomes (initial responders/non-responders, patients with pain recurrence/long-lasting pain relief at the last follow-up). Clinical and MRI predictors of treatment outcomes were explored. Cortical thinning of temporal, prefrontal, cingulate, somatosensory and occipital areas bilaterally was found in TN patients relative to controls. No cortical thickness and GM volume differences were observed when TN initial responders and non-responders were compared. Patients who experienced TN recurrence after initial pain relief were characterized by thicker parahippocampal and temporal cortices bilaterally and greater volume of right amygdala and hippocampus compared to patients with long-lasting pain relief. In TN patients, disease duration and baseline cortical thinning of right parahippocampal, left fusiform and middle temporal cortices were associated with poor outcome after GKS at the last follow-up (R2 =0.57, p<0.001). The study provides novel insights into structural brain alterations of TN patients, which might contribute to disease development and pain maintenance.

Effects and safety of high-frequency repetitive transcranial magnetic stimulation in trigeminal neuralgia

Background. Trigeminal neuralgia is the most common cause of facial pain. Insufficient effectiveness and frequent side effects of pharmacological therapy, as well as the risk of complications of invasive neurosurgical manipulations, determine the relevance of the development of new treatment approaches, one of which is repetitive transcranial magnetic stimulation (rTMS).The aim of the study is to determine the effectiveness of high‑frequency rTMS of the primary motor cortex in terms of pain intensity and quality of life in patients with trigeminal neuralgia, as well as to assess the safety of the stimulation course.Materials and methods. This open‑label non‑randomized single arm study included 20 patients with classic trigeminal neuralgia according to the ICHD‑3 classification. All patients received 10 sessions of navigated high‑frequency rTMS of the primary motor cortex (hand area) of the hemisphere, contralateral to pain syndrome localization. The maximum and average pain intensity was assessed before and after 10 rTMS sessions according to a Numeric Pain Rating Scale (NPRS), as well as quality of life was measured according to the SF‑36 questionnaire, and the severity of affective disorders according was measured to the Beck Depression Inventory (BDI). Safety and tolerability of rTMS were assessed using self‑developed questionnaires for adverse events that occurred during stimulation and within 24 hours after the previous session.Results. A significant decrease in the maximum (p = 0.01) and average (p &lt;0.01) pain intensity was shown after 10 sessions of rTMS. In 50 % of patients, the maximum pain intensity decreased by more than 30 % vs baseline. Significant changes were detected in the physical health measure of SF‑36 quality of life questionnaire, particularly, in the “bodily pain” domain, as well as in such aspects of the mental health measure as “vitality” and “social functioning”. The severity of affective disorders did not change significantly. A favorable profile of rTMS tolerability has been demonstrated.Conclusion. An open‑label study showed the possible effectiveness of 10 sessions of high‑frequency rTMS to reduceт the pain intensity in patients with trigeminal neuralgia. For the first time, the spectrum of adverse events both during stimulation and within a day after its completion was systematically analyzed.

A Prospective Study to Examine the Association of the Foramen Ovale Size with Intraluminal Pressure of Pear-Shaped Balloon in Percutaneous Balloon Compression for Trigeminal Neuralgia.

IntroductionPercutaneous balloon compression (PBC) is an effective and safe option for patients with trigeminal neuralgia. A pear-shaped balloon can be used to identify the proper compression of the Gasserian ganglion during the PBC procedure. The aim of this study was to evaluate the relationship between the foramen ovale (FO) size and intraluminal pressure of the pear-shaped balloon.MethodsThirteen patients that presented with classical trigeminal neuralgia were scheduled to undertake PBC surgery at the Pain Department of the Third Xiangya Hospital, Central South University, from November 2020 to April 2021. Three-dimensional computed tomography reconstruction of the skull base was performed to capture the feature of FO preoperatively. The intraluminal pressure was continuously recorded when a pear-shaped balloon was obtained during the procedure. Correlation analysis was calculated to determine the association of the intraluminal balloon pressure with FO parameter.ResultsAll participants reported complete relief of pain at discharge. The enduring analgesic effect of PBC was maintained in all patients with a median follow-up up to 5.5 months (range, 3–8 months). The average intraluminal balloon pressure was 161.5 ± 29.4 kPa at the initial compression (P1), and 134.8 ± 21.5 kPa at the ending of compression (P2), respectively. P1 was significantly correlated with the length (r = 0.61, P = 0.024) of FO. Similarly, a significant and positive correlation was observed between P2 and the length (r = 0.63, P = 0.022) of FO.ConclusionsPreoperative assessment of FO may be a potential predictor of intraluminal pressure to reach a pear-shaped balloon during PBC treatment. Narrow FO is associated lower intraluminal balloon pressure.

Radiofrequency thermocoagulation of trigeminal nerve assisted by nerve bundle extraction and image fusion based on hamilton-jacobi equation

Background and Objective: Radiofrequency thermocoagulation is an effective method for treating classic trigeminal neuralgia. However, the accurate positioning of thermocoagulation is difficult. The purpose of this study was to design an optimal strategy for performing adjuvant surgery.Methods: A total of 60 patients with trigeminal neuralgia were divided into two groups. One group received conventional computed tomography (CT) guided treatment (CT group). In the other group, neural fiber bundles were firstly extracted based on the Hamilton-Jacobi equation. Then, the MRI, CT, and fiber bundle images were fused to visualize the relationship among semilunar ganglion, trigeminal nerve, and puncture needle (fusion group).Results: Trigeminal fiber bundles were extracted quickly by the contour tracking method, and different types of image fusion were realized for radiofrequency surgery navigation. In the fusion group, 13.3% of patients could not reach semilunar ganglion, and 76.9% of the remaining cases reached the ideal damage area. In the CT group, the preoperative design shows that 26.7% of patients may have puncture difficulty, and 54.5% of remaining cases reached the ideal damage area.Conclusion: The technique of neural bundle extraction and image fusion based on the Hamilton-Jacobi equation can be used to plan the personalized puncture path targeting the semilunar ganglion.

Programming Parameters and Techniques in Trigeminal Ganglion Stimulation for Intractable Facial Pain

Atypical facial pain syndromes are challenging disorders to manage and often incur limited benefit with surgery for classical trigeminal neuralgia presentations, such as microvascular decompression or ablative procedures. Neurostimulation of the trigeminal ganglion and peripheral nerves can be effective at treating atypical presentations of trigeminal facial pain affecting the V1-3 dermatomes, and the surgical techniques are well described. The stimulation parameters, however, have thus far received limited description; we therefore sought to describe programming strategies. We performed a retrospective chart review, examining patients that underwent trigeminal ganglion stimulation (TGS) and nerve branch stimulation for atypical facial pain and trigeminal neuropathic pain, and describe the programming strategies in detail. We describe the use of high-frequency stimulation (1000Hz), with alteration in pulse width (60-220 msec) and amplitude (0.5-3 V) to achieve effective treatment of refractory trigeminal facial pain. These parameters differ from existing published parameters for trigeminal nerve branch stimulation. We also describe the programming of specific contacts on each lead to target specific aspects of the individual patients' facial pain. The use of effective programming strategies is critical to the success of neurostimulation surgical treatments; however, the critical details in programming strategies typically receive limited description. We report on the use of several successful programming strategies for TGS, to assist pain providers in successfully applying these surgical techniques in these difficult to manage atypical facial pain syndromes.

Peripheral Neurectomy for Trigeminal Neuralgia: A Report of Seventeen Cases and Review of the Literature.

Background:Surgical intervention for trigeminal neuralgia (TN) is indicated if there is a failure of the medical treatment. Peripheral neurectomy is one of the oldest surgical procedures for TN.Objective:The aim is to evaluate the clinical outcome and the recurrence rate following peripheral neurectomy for the management of TN.Patients and Methods:This was a retrospective cohort study of 17 patients with classical TN treated by peripheral neurectomy. The visual analogue scale (VAS) was used for pain assessment preoperatively and during the follow-up period. The outcome of surgery was graded as a marked, moderate, or mild improvement. Kaplan–Meier analysis was used for the time to recurrence to predict the probability of recurrence at any given time following the procedure.Results:The mean pain-free interval was 29.3 ± 16.3 months. At 2 and 5 years of the follow-up period, the mean VAS improved significantly (P < 0.001 and P = 0.042 respectively). Thirteen patients had marked improvement of pain. There was recurrence of pain in 4 patients (23.5%). By Kaplan–Meier analysis, the survival rate without recurrence at 2, 3, 4, and 5 years following the procedure were 92.9%, 79.6%, 59.7%, and 29.8%, respectively. The mean preoperative Hospital Anxiety and Depression Scale-Anxiety and Depression scores significantly improved on the last follow-up visit following the procedure (P < 0.001 for both).Conclusion:Peripheral neurectomy provides short to medium-term good pain control for patients with TN. The preoperative severity of pain, anxiety, and depression levels improved markedly after the procedure.

Microvascular decompression for trigeminal neuralgia: A retrospective analysis of long-term outcomes and prognostic factors

IntroductionMicrovascular decompression is considered to be the most effective and only etiological surgical treatment for classical trigeminal neuralgia, relieving the neurovascular compression found in up to 95% of cases. This study aims to report the long-term outcomes and to identify prognostic factors in a series of patients with trigeminal neuralgia treated by microvascular decompression. MethodsA retrospective observational study of 152 consecutive patients operated by microvascular decompression with at least six months of follow-up. The surgical results, including pain relief according to the Barrow Neurological Institute pain scale, complications and the medical treatment during the follow-up period were reviewed. Binary regression analysis was performed to identify factors associated with a good long-term outcome. ResultsA total of 152 patients with a mean age of 60 years and a mean follow-up of 43 months were included. At the final follow-up visit, 83% of the patients had achieved significant relief of the pain and 63% could reduce the absolute drug doses by 50% or more. The most frequent complications were wound infection (4.5%) and CSF fistula (7%). Being over 70 years of age and having paroxysmal pain were associated with a long-term pain relief. ConclusionsOur results support the notion that microvascular decompression is an effective and safe therapy in patients with trigeminal neuralgia. A multidisciplinary approach with an early referral to a neurosurgical unit many be beneficial in patients who are refractory to pharmacological treatment.

Prognostic nomogram for percutaneous balloon compression in the treatment of trigeminal neuralgia.

Because of its convenience and safety, percutaneous balloon compression (PBC) has become a more popular remedy for trigeminal neuralgia (TN) recently. The objective of this study was to establish a nomogram that can be used to preoperatively prognosticate the likelihood of pain-free based on preoperative disease characteristics. Clinical data were collected from those TN cases who had undergone PBC during the period of 2015 and 2020 in Qingdao Municipal Hospital. We excluded the cases caused by space-occupying lesion or had undergone MVD, percutaneous glycerol rhizotomy (PGR), and glycerol rhizotomy (GR). A nomogram was established based on the results of multivariable logistic analysis. A receiver operating characteristic curve (ROC) analysis was applied to evaluate the reliability of models. The plotted decision curves were also used to assess the net benefit of nomogram-assisted decisions. Internal validation was performed using the ROC by bootstrap sampling. Finally, 16 cases and 69 cases were included into the ineffective and effective groups respectively. In the crude, adjust I and adjust II models, response to carbamazepine positively, the grade II or III compression severity score, and classical TN type were all considered to be significant predictors of pain relief (BNI grades I-III) at 3 months' follow-up. The AUC, accuracy, specificity, and sensitivity of the nomogram system were 0.83, 0.85, 0.75, and 0.87 respectively for predicting patient outcomes. The decision curves showed good performance for the nomogram system in terms of clinical application, while more research with validation in multiple, external independent patient populations is needed.

A differential participation of voltage gated sodium channels is related to the selective efficacy of carbamazepine in trigeminal neuralgia

This study is based on the clinical observations that a subpopulation of patients suffering from classical trigeminal neuralgia are responsive to the anti-seizure, voltage-gated Na+ channel (VGSC)-blocking drugs carbamazepine (CBZ) and oxcarbamazepine while these drugs have failed to demonstrate efficacy in clinical trials with other neuropathic pain conditions, even those associated with nerve compression injuries. Furthermore, with preclinical evidence of afferent subpopulation specific responses to injury, we hypothesized that the therapeutic selectivity of carbamazepine for TN reflects the unique combination of injury-induced changes in VGSCs in the trigeminal nerve. We found that potency and efficacy of CBZ-induced inhibition of the compound action potential (CAP) was increased following chronic constriction injury (CCI) of the infraorbital nerve (ION), but not of the sciatic nerve (SN).. The potency of CBZ-induced block of the CAP evoked in human spinal nerves was comparable to the SN from rats, but was more potent in the block of the CAP evoked in human trigeminal nerves. Among different VGSCs blockers evaluated, the efficacy of ICA121431 (Nav 1.1 and 1.3 blocker) was significantly greater in the inhibition of the Ab and C components of the ION CAP compared to the SN CAP from the sham group, and CCI of the ION but not SN was associated with an increase in efficacy and potency of ICA121431 on the inhibition of the Ab and C components of the CAP. A CCI-induced increase in Nav 1.1-like immunoreactivity was detected with western blot of protein extracted from the ION, while a CCI-induced increase in Nav 1.3-like immunoreactivity was detected in the SN. Finally, local administration of ICA121431 on the ION alleviated mechanical hypersensitivity in rats with ION-CCI. Our results are consistent with our initial hypothesis and suggest that the therapeutic selectivity of CBZ is related to a differential regulation of the VGSC. This work was supported by generous donations from TN patients and family members as well as NIH grant R01NS064988.