Risk of psychiatric disorders following trigeminal neuralgia: a nationwide population-based retrospective cohort study

Foxg1 Modulation of the Prkcd Gene in the Lateral Habenula Mediates Trigeminal Neuralgia-Associated Anxiety-Like Behaviors in Mice

Trigeminal Neuralgia (TN) is a debilitating disorder frequently accompanied by mood complications such as depression and anxiety. The current study sought to elucidate the molecular underpinnings that contribute to the pathogenesis of TN and its associated anxiety. Employing a partial transection of the infraorbital nerve (pT-ION) in a murine model, we successfully induced sustained primary and secondary orofacial allodynia alongside anxiety-like behavioral manifestations. Transcriptome-wide gene microarray analyses revealed a marked upregulation of Foxg1 subsequent to pT-ION. Targeted knockdown of Foxg1, achieved through bilateral microinjection of adeno-associated virus harboring Foxg1-specific shRNA into the lateral habenula (LHb), resulted in a significant attenuation of both orofacial pain and anxiety-like behaviors. Subsequent RNA sequencing implicated Prkcd as a downstream effector gene modulated by Foxg1. Pharmacological inhibition of protein kinase C delta, encoded by Prkcd, within the LHb markedly ameliorated pT-ION-induced symptomatology. The dual luciferase assay revealed that Foxg1 substantially enhances the transcriptional activity of the Prkcd gene. Collectively, these findings indicate that trigeminal nerve injury leads to Foxg1 upregulation in the LHb, which in turn elevates the expression of Prkcd, culminating in the manifestation of orofacial pain and anxiety-like behaviors. This work offers promising therapeutic targets and a conceptual framework for the clinical management of TN and its psychological comorbidities.

Trigeminal neuralgia

Trigeminal neuralgia (TN) is a facial pain disorder characterized by intense and paroxysmal pain that profoundly affects quality of life and presents complex challenges in diagnosis and treatment. TN can be categorized as classical, secondary and idiopathic. Epidemiological studies show variable incidence rates and an increased prevalence in women and in the elderly, with familial cases suggesting genetic factors. The pathophysiology of TN is multifactorial and involves genetic predisposition, anatomical changes, and neurophysiological factors, leading to hyperexcitable neuronal states, central sensitization and widespread neural plasticity changes. Neurovascular compression of the trigeminal root, which undergoes major morphological changes, and focal demyelination of primary trigeminal afferents are key aetiological factors in TN. Structural and functional brain imaging studies in patients with TN demonstrated abnormalities in brain regions responsible for pain modulation and emotional processing of pain. Treatment of TN involves a multifaceted approach that considers patient-specific factors, including the type of TN, with initial pharmacotherapy followed by surgical options if necessary. First-line pharmacological treatments include carbamazepine and oxcarbazepine. Surgical interventions, including microvascular decompression and percutaneous neuroablative procedures, can be considered at an early stage if pharmacotherapy is not sufficient for pain control or has intolerable adverse effects or contraindications.

Clinical observation of perioperative negative emotional changes in patients with percutaneous balloon compression for primary trigeminal neuralgia: A prospective cohort study

OBJECTIVE

To investigate the prevalence of negative emotions in trigeminal neuralgia (TN) patients, to identify risk factors associated with anxiety and depression, and further to explore the impact of percutaneous balloon compression (PBC) on anxiety and depression in TN patients during the perioperative period.

METHODS

400 patients with primary TN treated with PBC at our institution from November 2021 to April 2023 were included. We analyzed visual analogue scale (VAS) and the Hospital Anxiety and Depression Scale (HADS) scores. The patients' clinical data and short-term clinical outcomes were gathered and subjected to statistical analysis.

RESULTS

This study included a total of 400 patients diagnosed with primary TN. Patients who had high pain intensity (OR 1.20, 95 % CI 1.02-1.41; p = 0.025) or a history of multiple previous TN procedures (OR 1.49, 95 % CI 1.03-2.16; p = 0.036), were more prone to anxiety. Patients who were female (OR 1.59, 95 % CI 1.03-2.44; p = 0.036), had high pain intensity (OR 1.28, 95 % CI 1.08-1.52; p = 0.004) or had a history of multiple previous TN procedures (OR 1.48, 95 % CI 1.11-1.98; p = 0.008), were more likely to have depression. Significant improvements in anxiety and depressive symptoms were observed in patients who experienced pain relief after PBC (p < 0.001).

CONCLUSIONS

Female gender, high pain intensity, and a history of multiple prior TN procedures are associated risk factors for anxiety and depression in TN patients. PBC can provide patients with a high pain relief rate and significantly improve their anxiety and depression symptoms during the perioperative period.

Trigeminal Neuralgia as a Primary Demyelinating Disease: Potential Multimodal Evidence and Remaining Controversies

Trigeminal neuralgia is a heterogeneous disorder with likely multifactorial and complex etiology; however, trigeminal nerve demyelination and injury are observed in almost all patients with trigeminal neuralgia. The current management strategies for trigeminal neuralgia primarily involve anticonvulsants and surgical interventions, neither of which directly address demyelination, the pathological hallmark of trigeminal neuralgia, and treatments targeting demyelination are not available. Demyelination of the trigeminal nerve has been historically considered a secondary effect of vascular compression, and as a result, trigeminal neuralgia is not recognized nor treated as a primary demyelinating disorder. In this article, we review the evolution of our understanding of trigeminal neuralgia and provide evidence to propose its potential categorization, at least in some cases, as a primary demyelinating disease by discussing its course and similarities to multiple sclerosis, the most prevalent central nervous system demyelinating disorder. This proposed categorization may provide a basis in investigating novel treatment modalities beyond the current medical and surgical interventions, emphasizing the need for further research into demyelination of the trigeminal sensory pathway in trigeminal neuralgia. PERSPECTIVE: This article proposes trigeminal neuralgia as a demyelinating disease, supported by histological, clinical, and radiological evidence. Such categorization offers a plausible explanation for controversies surrounding trigeminal neuralgia. This perspective holds potential for future research and developing therapeutics targeting demyelination in the condition.

Corticotropin-releasing hormone neurons control trigeminal neuralgia-induced anxiodepression via a hippocampus-to-prefrontal circuit

Anxiety and depression are frequently observed in patients suffering from trigeminal neuralgia (TN), but neural circuits and mechanisms underlying this association are poorly understood. Here, we identified a dedicated neural circuit from the ventral hippocampus (vHPC) to the medial prefrontal cortex (mPFC) that mediates TN-related anxiodepression. We found that TN caused an increase in excitatory synaptic transmission from vHPCCaMK2A neurons to mPFC inhibitory neurons marked by the expression of corticotropin-releasing hormone (CRH). Activation of CRH+ neurons subsequently led to feed-forward inhibition of layer V pyramidal neurons in the mPFC via activation of the CRH receptor 1 (CRHR1). Inhibition of the vHPCCaMK2A-mPFCCRH circuit ameliorated TN-induced anxiodepression, whereas activating this pathway sufficiently produced anxiodepressive-like behaviors. Thus, our studies identified a neural pathway driving pain-related anxiodepression and a molecular target for treating pain-related psychiatric disorders.

Management of trigeminal neuralgia: A multi-centre case study in general practice

Background and aims

Patients often first present with symptoms of trigeminal neuralgia (TN) to primary care. However, there has been little research to determine whether the diagnosis and management of this condition is carried out according to current guidelines. Furthermore, there is little up-to-date information regarding the prevalence of TN in the UK. The aim is to estimate the prevalence of TN and to audit the diagnosis and management process of TN in primary care.

Methods

Between 2019 and 2020 a search was made at five UK GP practices with a total patient population of 55,842 using EMIS and SystmOne patient record systems to review patient consultations to identify patients coded with TN or facial pain (FP). These records were reviewed to ascertain the basis for diagnosis, management in primary care and referral to secondary care.

Results

157 patients were identified; 54 coded with FP and 103 with TN. These results indicate a prevalence of 22.3 in 10,000. There was no difference in documented symptoms between the two groups. Seven patients had all ICDH3 criteria recorded, with two meeting the requirements for TN diagnosis. 58.8% of patients with TN were started on carbamazepine, the current gold standard treatment, compared with 16.7% in the FP group. 38.2% of TN patients were referred to a range of different specialities.

Conclusion

The prevalence of TN may be higher than previously thought. Key diagnostic criteria are often omitted, leading to potential misdiagnosis or delays in diagnosis. Relatively few referrals are made, though all patients should be considered for imaging.

Percutaneous glycerol rhizolysis of the trigeminal ganglion for the treatment of idiopathic and classic trigeminal neuralgia: Outcomes and complications

BACKGROUND AND PURPOSE

Patients with idiopathic trigeminal neuralgia (TN) with absent arterial contact or venous contact only and classic TN with morphological changes of the trigeminal nerve secondary to venous compression are not routinely recommended microvascular decompression at our institution. In patients with these anatomical subtypes of TN, limited data exists describing the outcomes of percutaneous glycerol rhizolysis (PGR) of the trigeminal ganglion (TG).

METHODS

We performed a retrospective single-center cohort study and analyzed outcomes and complications after PGR of the TG. Clinical outcome after PGR of the TG was assessed via the Barrow Neurological Institute (BNI) Pain Scale.

RESULTS

Forty-five patients underwent a total of 66 PGRs of the TG. At short-term follow-up, 58 procedures (87.9%) resulted in a BNI score of I (i.e., freedom from pain without medication). At a median follow-up of 3.07 years, 18 procedures (27.3%) resulted in a BNI score of I, 12 procedures (18.1%) resulted in BNI score of IIIa, and 36 procedures (54.5%) resulted in a BNI score of IIIb-V. The median length of freedom from pain without medication was 1.5 years. Eighteen procedures (27.3%) caused hypesthesia and two (3.0%) caused paresthesias. There were no serious complications.

CONCLUSION

In patients with these anatomical subtypes of TN there was a high rate of short-term pain relief for the first 1-2 years and thereafter a large proportion of patients experienced pain relapse. In this patient group, PGR of the TG represents a safe procedure that is efficacious in the short term.

A multimodal meta-analysis of gray matter alterations in trigeminal neuralgia

Background

Brain gray matter alterations in patients with trigeminal neuralgia (TN) have been detected in prior neuroimaging studies, but the results are heterogeneous. The current study conducted coordinate-based meta-analyses across neuroimaging studies, aiming to find the pattern of brain anatomic and functional alterations in patients with TN.

Methods

We performed a systematic literature search of PubMed, Embase, and Web of Science to identify relevant publications. A multimodal meta-analysis for whole-brain voxel-based morphometry (VBM) studies and functional imaging studies in TN was performed using anisotropic effect size-based signed differential mapping.

Results

The meta-analysis comprised 10 VBM studies with 398 TN patients and 275 healthy controls, and 13 functional magnetic resonance imaging studies with 307 TN patients and 264 healthy controls. The multimodal meta-analysis showed conjoint structural and functional brain alterations in the right fusiform gyrus and inferior temporal gyrus, bilateral thalamus, left superior temporal gyrus, left insula, and inferior frontal gyrus. The unimodal meta-analysis showed decreased gray matter volume alone in the left putamen, left postcentral gyrus, and right amygdala as well as only functional abnormalities in the left cerebellum, bilateral precuneus, and left middle temporal gyrus.

Conclusion

This meta-analysis revealed overlapping anatomic and functional gray matter abnormalities in patients with TN, which may help provide new insights into the neuropathology and potential treatment biomarkers of TN.

Parabrachial Nucleus Activity in Nociception and Pain in Awake Mice

The parabrachial nuclear complex (PBN) is a nexus for aversion and for the sensory and affective components of pain perception. We have previously shown that during chronic pain PBN neurons in anesthetized rodents have amplified activity. We report a method to record from PBN neurons of behaving, head-restrained mice while applying reproducible noxious stimuli. We find that both spontaneous and evoked activity are higher in awake animals compared with urethane anesthetized mice. Fiber photometry of calcium responses from calcitonin-gene-related peptide-expressing PBN neurons demonstrates that these neurons respond to noxious stimuli. In both males and females with neuropathic or inflammatory pain, responses of PBN neurons remain amplified for at least 5 weeks, in parallel with increased pain metrics. We also show that PBN neurons can be rapidly conditioned to respond to innocuous stimuli after pairing with noxious stimuli. Finally, we demonstrate that changes in PBN neuronal activity are correlated with changes in arousal, measured as changes in pupil area.SIGNIFICANCE STATEMENT The parabrachial complex is a nexus of aversion, including pain. We report a method to record from parabrachial nucleus neurons of behaving mice while applying reproducible noxious stimuli. This allowed us to track parabrachial activity over time in animals with neuropathic or inflammatory pain. It also allowed us to show that the activity of these neurons correlates with arousal states and that these neurons can be conditioned to respond to innocuous stimuli.

Evaluation of anxiety disorder in patients with trigeminal neuralgia

BACKGROUND

The aim of this cross-sectional study was to evaluate the relationship between anxiety levels and severity of trigeminal neuralgia (TN) disorder's chronic orofacial pain during 2019-2020 in Shiraz Dental Faculty.

METHODS

In this study, patients with TN disorder who were referred to the Oral Medicine Department of Shiraz Dental Faculty were evaluated. Individuals were selected based on convenience sampling. Finally, 47 patients with TN were recruited in this study. Satisfaction with treatment was recorded based on controlling the patient's pain, age, sex, and frequency of recurrence, and data were analyzed using SPSS18. The Chi-square test was used to compare the final results. A reliability of more than 95% was considered significant (P < 0.05).

RESULTS

According to the results, the mean ages of participants with TN and control groups were 56.89 ± 10.93 and 37.12 ± 9.55, respectively. The mean value of participants' age was significantly different between the two evaluated groups (P < 0.0001). The anxiety of patients with TN was significantly higher than the healthy control group (P < 0.0001). The mean level of anxiety in patients with TN and also in healthy controls was not significantly different among men and women (P > 0.05). The mean level of anxiety of men and women in TN group was significantly higher than the healthy control women (P = 0.001). The mean levels of anxiety between different age ranges in patients with TN and healthy controls were not different in both evaluated groups (P > 0.05). Patients with TN in different age ranges had higher level of anxiety than healthy controls (P < 0.05).

CONCLUSION

Patients with TN had significantly higher level of anxiety than healthy participants.

The Superior Cerebellar Artery: Variability and Clinical Significance

The superior cerebellar artery (SCA) arises from the distal part of the basilar artery and passes by the oculomotor, trochlear, and trigeminal nerves. SCA is known to play a crucial role in the development of trigeminal neuralgia. However, due to its anatomical variability, it may also trigger other neurovascular compression (NVC), including hemifacial spasm, oculomotor nerve palsy, and ocular neuromyotonia. Additionally, it may be associated with ischemic syndromes and aneurysm development, highlighting its clinical significance. The most common anatomical variations of the SCA include duplication, a single vessel origin from the posterior cerebral artery (PCA), and a common trunk with PCA. Rarely observed variants include bifurcation and origin from the internal carotid artery. Certain anatomical variants such as early bifurcation and caudal course of duplicated SCA trunk may increase the risk of NVC. In this narrative review, we aimed to examine the impact of the anatomical variations of SCA on the NVCs based on papers published in Pubmed, Scopus, and Web of Science databases with a snowballing approach. Our review emphasizes the importance of a thorough understanding of the anatomical variability of SCA to optimize the management of patients with NVCs associated with this artery.

Effects of Ayurveda interventions on acute pain and quality of life of a trigeminal neuralgia patient - A case report

Classical trigeminal neuralgia (CTN) is a disease characterized by severe pain in the facial area related to the trigeminal nerve. CTN occurs due to neurovascular compression of the Trigeminal nerve presenting with recurrent pain episodes. This case reports the effect of Ayurveda interventions on CTN. Thirty-nine-year-old male patient with pain on the right side of the face for two years presented to the National Institute of Ayurveda, Hospital, Jaipur, Rajasthan, India. The pain was distributed on the right side of the upper lip, cheek, and chin. Paroxysms of pain appeared at the interval of 1-2 h and were lasting of 1-2 min. The case was diagnosed with the help of magnetic resonance imaging (MRI) as right-side classical trigeminal neuralgia due to indentation of the vascular loop of the right superior cerebellar artery. The patient had a treatment history of two years with allopathic medicine, and he sought Ayurveda treatment due to recurrence and excessive pain. The patient was given Ayurvedic interventions (oral medication, Nasya, Kavalagraha, and Gandusha) for three months. The improvement were observed on the visual analogue scale (VAS) for pain, hospital anxiety and depression scale (HADS), and Short Form -36 questionnaire (SF-36) for quality of life. After three months of the treatment, the VAS scale for pain and the HADS scale for anxiety and depression showed marked improvement. Improvement in all the domains of SF-36 was observed, with a total percentage improvement from 10.7% to 83.2%. Observations of this case highlight the usefulness of Ayurveda interventions, i.e., Oral medication, Nasya, Kavalagraha, and Gandusha, in reducing the acute paroxysms of pain in Classical TN and improving the quality of life of CTN patients.

Preclinical orofacial pain assays and measures and chronic primary orofacial pain research: where we are and where we need to go

Chronic primary orofacial pain (OFP) conditions such as painful temporomandibular disorders (pTMDs; i.e., myofascial pain and arthralgia), idiopathic trigeminal neuralgia (TN), and burning mouth syndrome (BMS) are seemingly idiopathic, but evidence support complex and multifactorial etiology and pathophysiology. Important fragments of this complex array of factors have been identified over the years largely with the help of preclinical studies. However, findings have yet to translate into better pain care for chronic OFP patients. The need to develop preclinical assays that better simulate the etiology, pathophysiology, and clinical symptoms of OFP patients and to assess OFP measures consistent with their clinical symptoms is a challenge that needs to be overcome to support this translation process. In this review, we describe rodent assays and OFP pain measures that can be used in support of chronic primary OFP research, in specific pTMDs, TN, and BMS. We discuss their suitability and limitations considering the current knowledge of the etiology and pathophysiology of these conditions and suggest possible future directions. Our goal is to foster the development of innovative animal models with greater translatability and potential to lead to better care for patients living with chronic primary OFP.

Sex differences in the role of parabrachial in nociception and pain in awake mice.. [PMID: 36993729 PMCID: PMC10055376 DOI: 10.1101/2023.03.22.533230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The parabrachial nucleus is a nexus for aversion, and for the sensory and affective components of pain. In anesthetized rodents with chronic pain, parabrachial neurons have amplified activity. Both spontaneous and evoked activity are considerably higher in awake, compared to anesthetized animals. Parabrachial neurons are rapidly conditioned to respond to innocuous stimuli, after pairing with nociceptive stimuli. In neuropathic or inflammatory pain, parabrachial responses remain amplified for at least 6 weeks, in parallel with increased pain metrics. Calcium responses from CGRP- expressing parabrachial neurons in males demonstrate responses to nociceptive stimuli, and amplified activity in inflammatory pain. In females these neurons evoke smaller responses at baseline, and only small increases in neuropathic pain. This sex difference may relate to our finding that, in females, a small percentage of neurons expresses CGRP RNA. Finally, we show that changes in parabrachial activity are correlated with in arousal, measured as changes in pupil size.

Locus coeruleus-noradrenergic modulation of trigeminal pain: Implications for trigeminal neuralgia and psychiatric comorbidities

Trigeminal neuralgia is the most common neuropathic pain involving the craniofacial region. Due to the complex pathophysiology, it is therapeutically difficult to manage. Noradrenaline plays an essential role in the modulation of arousal, attention, cognitive function, stress, and pain. The locus coeruleus, the largest source of noradrenaline in the brain, is involved in the sensory and emotional processing of pain. This review summarizes the knowledge about the involvement of noradrenaline in acute and chronic trigeminal pain conditions and how the activity of the locus coeruleus noradrenergic neurons changes in response to acute and chronic pain conditions and how these changes might be involved in pain-related comorbidities including anxiety, depression, and sleep disturbance.

CyberKnife radiosurgery for trigeminal neuralgia: a retrospective review of 168 cases

OBJECTIVE

Gamma Knife radiosurgery is recognized as an efficient intervention for the treatment of refractory trigeminal neuralgia (TN). The CyberKnife, a more recent frameless and nonisocentric radiosurgery alternative, has not been studied as extensively for this condition. This study aims to evaluate the clinical outcomes of a first CyberKnife radiosurgery (CKRS) treatment in patients with medically refractory TN.

METHODS

A retrospective cohort study of 166 patients (168 procedures) with refractory TN treated from 2009 to 2021 at the Centre Hospitalier de l’Université de Montréal was conducted. The treatment was performed using a CyberKnife (model G4, VSI, or M6). The treatment median maximum dose was 80 (range 70.0–88.9) Gy.

RESULTS

Adequate pain relief, evaluated using Barrow Neurological Institute pain scale scores (I–IIIb), was achieved in 146 cases (86.9%). The median latency period before adequate pain relief was 35 (range 0–202) days. The median duration of pain relief for cases with a recurrence of pain was 8.3 (range 0.6–85.0) months. The actuarial rates of maintaining adequate pain relief at 12, 36, and 60 months from the treatment date were 77.0%, 62.5%, and 50.2%, respectively. There was new onset or aggravation of facial numbness in 44 cases (26.2%). This facial numbness was predictive of better maintenance of pain relief (p < 0.001). The maintenance of adequate pain relief was sustained longer in idiopathic cases compared with cases associated with multiple sclerosis (MS; p < 0.001).

CONCLUSIONS

In the authors’ experience, CKRS for refractory TN is efficient and safe. The onset or aggravation of facial hypoesthesia after treatment was predictive of a more sustained pain relief, and idiopathic cases had more sustained pain relief in comparison with MS-related cases.

A novel implantable device for sensory and affective assessment of orofacial pain in rats

Background and objective

Orofacial pain, in particular, chronic orofacial pain remains a great challenge in clinical practice. To better understand the underlying mechanism of disease, it is essential to apply a feasible and stable preclinical measurement of facial pain. Here, we introduced a novel electrical noxious stimulator in freely behavioral rodents and examined its validation in both naïve and chronic orofacial pain animals.

Methods

One subcutaneous device of electrical stimulator was implanted in the facial region for delivery of the nociceptive input. The sensory component of orofacial pain was assessed by response scoring tool, and conditioned place aversion (CPA) paradigm for pain affect respectively. To confirm its usage in chronic pain state, the chronic constriction injury of the infraorbital nerve (ION-CCI) model was then applied.

Results

We found that responsive scores increased with stimulation intensity, and acted in a dosage-dependent manner, which can be attenuated by the administration of morphine intraperitoneally. Naïve rats displayed significant aversive reaction to the noxious electrical stimulation (25V) in the CPA testing. In addition, an obvious sensory hypersensitivity to electrical stimulation was confirmed by the increased response scores in ION-CCI rats. Furthermore, ION-CCI animal showed significant avoidance to electrical stimulation at relatively low intensity (10V), which was innoxious to naïve rats.

Conclusion

Our findings may provide an alternative pre-clinical measurement of orofacial pain, to quantitively assess both sensory and affective component of orofacial pain.

Psychologic Impact of Chronic Orofacial Pain: A Critical Review

AIMS

To explore the prevalence of clinically significant anxiety and depression in adult patients with chronic orofacial pain (COFP) conditions.

METHODS

A systematic online search of the Medline (PubMed) and Ovid databases was performed for articles published from 2006 to 2019. Observational studies- including cross-sectional, case-control, and case series-and longitudinal prospective studies were included. A total of 118 articles were selected for inclusion, and the prevalence rates of clinically significant anxiety and depression were summarized.

RESULTS

Most studies focused on temporomandibular disorder (TMD) pain and less often on neuropathic COFP conditions. Prevalence rates varied widely across studies according to OFP condition and assessment measure; most questionnaire-based assessments yielded rates of clinically significant depression and anxiety in, respectively, 40% to 60% and 40% to 65% of individuals with TMD and in 20% to 50% and 25% to 55% of patients with neuropathic, mixed, or idiopathic/atypical COFP conditions. Rates of anxiety and depression were lower in studies using diagnostic instruments and in TMD studies with nonpatient samples. Most controlled studies showed a higher prevalence of anxiety and depression in individuals with COFP than in those without. Higher COFP pain levels and the presence of comorbid conditions such as migraines or widespread pain increased the likelihood of anxiety and/or depressive symptoms in individuals.

CONCLUSION

Clinically significant anxiety and depression were commonly observed in patients with COFP, were present at higher rates than in pain-free participants in controlled studies, and were closely linked to pain severity. More research is needed to evaluate the psychologic impact of multiple COFP conditions in an individual and the prevalence of precondition psychologic morbidity.

Structural and Functional Brain Changes in Patients With Classic Trigeminal Neuralgia: A Combination of Voxel-Based Morphometry and Resting-State Functional MRI Study

Objectives

Brain structural and functional abnormalities have been separately reported in patients with classic trigeminal neuralgia (CTN). However, whether and how the functional deficits are related to the structural alterations remains unclear. This study aims to investigate the anatomical and functional deficits in patients with CTN and explore their association.

Methods

A total of 34 patients with CTN and 29 healthy controls (HCs) with age- and gender-matched were recruited. All subjects underwent structural and resting-state functional magnetic resonance imaging (fMRI) scanning and neuropsychological assessments. Voxel-based morphometry (VBM) was applied to characterize the alterations of gray matter volume (GMV). The amplitude of low-frequency fluctuation (ALFF) method was used to evaluate regional intrinsic spontaneous neural activity. Further correlation analyses were performed between the structural and functional changes and neuropsychological assessments.

Results

Compared to the HCs, significantly reduced GMV was revealed in the right hippocampus, right fusiform gyrus (FFG), and temporal-parietal regions (the left superior/middle temporal gyrus, left operculo-insular gyrus, left inferior parietal lobule, and right inferior temporal gyrus) in patients with CTN. Increased functional activity measured by zALFF was observed mainly in the limbic system (the bilateral hippocampus and bilateral parahippocampal gyrus), bilateral FFG, basal ganglia system (the bilateral putamen, bilateral caudate, and right pallidum), left thalamus, left cerebellum, midbrain, and pons. Moreover, the right hippocampus and FFG were the overlapped regions with both functional and anatomical deficits. Furthermore, GMV in the right hippocampus was negatively correlated with pain intensity, anxiety, and depression. GMV in the right FFG was negatively correlated with illness duration. The zALFF value in the right FFG was positively correlated with anxiety.

Conclusion

Our results revealed concurrent structural and functional changes in patients with CTN, indicating that the CTN is a brain disorder with structural and functional abnormalities. Moreover, the overlapping structural and functional changes in the right hippocampus and FFG suggested that anatomical and functional changes might alter dependently in patients with CTN. These findings highlight the vital role of hippocampus and FFG in the pathophysiology of CTN.

Trigeminal Neuralgia Is a Dementia Risk Factor: A Retrospective Cohort Study

Background: Dementia, a worldwide public-health issue, is regarded as a disorder rather than a normal aging process. Trigeminal neuralgia (TN) is a chronic debilitating pain disorder that impairs daily activities. Both are most prevalent in females and in patients older than 50 years. Recent studies reveal that pain and dementia may have a reciprocal interaction with each other. Objective: In response, we estimated whether adults with TN have an increased dementia risk. Methodology: By means of Taiwan's National Health Insurance Research Database, between 1996 and 2010, 762 patients aged over 50 years in the TN group were matched with 3048 patients in the non-TN group at a ratio of 1:4. Kaplan-Meier method and Cox proportional hazard regression models were also used to determine the cumulative incidence and compare the hazard ratios of dementia in each group. Results: The incidence of dementia was higher in the TN group compared to the non-TN group. After adjusting for covariates, the TN group had a 4.47-fold higher risk of dementia compared to the non-TN group. Additionally, the impact of TN on dementia risk was larger in young-aged patients than in old-aged patients. As well, the age at the time of dementia diagnosis was younger in the TN group compared to the non-TN group. Conclusions: TN is a dementia risk factor. Given the lack of a curative therapy for dementia, early identification of TN patients may help to prevent dementia sequelae.

Autologous conditioned serum (Orthokine) injection for treatment of classical trigeminal neuralgia: results of a single-center case series

BACKGROUND

Despite some advances, treatment of trigeminal neuralgia remains a significant challenge. This study determines the efficacy and safety of autologous conditioned serum (Orthokine) injection into the foramen oval to treat refractory trigeminal neuralgia.

CASE PRESENTATION

This is a consecutive case series from the Pain and Palliative Care Department of Imam Reza University Hospital, Tabriz, Iran. Eleven Iranian patients, eligible according to the inclusion and exclusion criteria, aged 45.64 ± 11.58 years (Four male and seven female, all Iranian) with established classical trigeminal neuralgia were injected with Orthokine (2 mL per injection) once a week for three consecutive weeks (total of four injections). Numeric rating scale scores for facial pain intensity and also carbamazepine daily dose were confirmed at pretreatment (T0) and at week 1 (T1), week 2 (T2), week 3 (T3), week 4 (T4), and month 2 (T5) posttreatment. Pain intensity was significantly reduced in the first 3 weeks of follow-up in comparison with baseline (T0 to T3) (8.18 ± 1.99 to 2.82 ± 2.13, p < 0.001), an effect that was retained at week 4 (T4) and month 2 (T5) follow-ups (2.82 ± 2.13 to 3.36 ± 2.69, p = 0.886). Carbamazepine consumption was significantly reduced in the first 3 weeks of follow-up in comparison with baseline (T0 to T3) (636.36 ± 307.48 to 200.00 ± 296.64, p = 0.003), an effect that was retained at week 4 and month 2 follow-ups (200.00 ± 296.64 to 200.00 ± 282.84, p = 0.802). There were no serious adverse events in participants.

CONCLUSION

Orthokine injection led to consistent pain relief and reduced carbamazepine dosage in patients with trigeminal neuralgia, with acceptable safety.

The Risk of Trigeminal Neuralgia Following Osteoporosis

Background and objectives: Managing people with trigeminal neuralgia (TN) and osteoporosis is challenging due to their debilitating conditions. Currently, the exact association between TN and osteoporosis in patients remains unknown, although there is potential overlapping of pathophysiological mechanisms. In response, we calculated TN risk in patients who have osteoporosis. Materials and Methods: 45,393 patients aged over 50 years diagnosed with osteoporosis were matched with 45,393 non-osteoporosis patients aged over 50 years (1:1 ratio) who were used as the control group, using data from 1996 to 2010 from Taiwan’s National Health Insurance Research Database. The cumulative incidences of subsequent TN and the hazard ratio were estimated using Cox proportional hazards modeling and the Kaplan–Meier method, respectively. Results: Among the total sample, 333 patients were diagnosed with TN during the follow-up period: 205 in the osteoporosis cohort and 128 in the control cohort. Through covariate adjustment, the overall TN incidence showed a 1.80-fold increase in the osteoporosis cohort in comparison with the control cohort (0.60 vs. 0.18 per 1000 person-years, respectively). The High Charlson Comorbidity Index, hypertension, and migraines were risk factors of TN. Conclusions: Osteoporosis patients had a higher TN risk than that of the control cohort. Therefore, early recognition of pain and symptoms in osteoporotic people may help to identify possible TN patients who need prompt therapy.

When intra-operative exploration is the only option, severe medically refractory trigeminal neuralgia

Introduction: Patients with trigeminal neuralgia (TN) are usually treated on an outpatient basis, and symptoms can be controlled using various medical therapeutic options. We present a case of severe TN with an acute on chronic flare, which was now refractory to a wide variety of medical options, had a prolonged inpatient hospitalization, and ultimately required surgery with excellent results.Case: A 54-year-old Hispanic male was admitted with severe left-sided TN. His symptoms gradually became more pronounced and frequent to a point where he was unable to have a meaningful quality of life. A trial of gabapentin, phenytoin, opioids, and NSAIDs had also been unsuccessful before this hospitalization. He had three ER visits before he was finally hospitalized with intractable pain and unfortunately had begun to have suicidal thoughts. Various therapeutic interventions were tried, including escalating doses of opioids and local nerve blocks, but all non-surgical options failed to provide relief. Neurosurgical route was eventually approached, and patient underwent left retro mastoid suboccipital craniectomy. Intraoperatively, the left superior cerebellar artery was found to adhere to the inferior ventral aspect of the left trigeminal nerve root entry zone. Upon decompression patient's symptoms resolved dramatically. Interestingly this vascular compression was not seen on multiple prior brain imaging.Conclusion: TN can severely affect someone's quality of life. It often leads to severe anxiety and depression. Our case represents the importance of proceeding towards surgical options sooner rather than later. An early multi-disciplinary approach is warranted.

The journeys of patients with trigeminal neuralgia on a background of multiple sclerosis

Aim: Multiple sclerosis (MS) is well recognized as a secondary cause for trigeminal neuralgia (TN). In this case series, we detail the management of all the patients with TN and MS (pwTNMS) presenting to a specialist unit. Materials & methods: A prospective patient database was used to extract key clinical data on pharmacological, psychometric and surgical management of 20 pwTNMS. Results: 65% of pwTNMS underwent surgical interventions for management of their pain.12/20 achieved remission periods, through surgery and/or medication. Significant improvement was noted on the global impression of change illustrated by a p < 0.001. Conclusion: pwTNMS require a multifaceted approach combining polypharmacy, surgical interventions and psychological support. Developing self-management skills is crucial if patients are to live well with pain.

Recent Advances in Trigeminal Neuralgia and Its Management: A Narrative Review

Trigeminal neuralgia (TN) is a chronic facial pain condition that affects one or more divisions of the trigeminal nerve (5th cranial nerve). It can be idiopathic, primary, or secondary. The cornerstone of the therapy has been antiepileptic medications, peripheral nerve blocks with various neurolytic agents, and surgical procedures. With the advent of newer technologies, minimally invasive neurolytic techniques like low-level laser therapy and ozone injection have revolutionized the management of TN. Novel drugs like vixotrigine and eslicarbazepine have been promising in reducing the frequency and severity of attacks. Inhaled carbon dioxide too has shown promising results in initial trials. Neuromodulation has given robust data in controlling neuralgic pain especially refractory to medical management. Pulsed radiofrequency has been used with increasing success and the side effects like dysesthesia and paresthesia are less. Cryotherapy, neural prolotherapy, and fiber knife techniques have helped us believe that TN can be controlled and cured. The need of the hour is to develop and explore newer modalities for trigeminal neuralgia treatment with minimum side effects. In this narrative review, we have tried to shed light into the newer modalities of treatment of TN along with new clinical classification for better disease recognition and management.

Psychological status before and after surgery in patients with trigeminal neuralgia

OBJECTIVE

To analyze the psychological status in patients with trigeminal neuralgia before surgery and in the early postoperative period after microvascular decompression of the trigeminal nerve.

METHODS

Psychological features of personality were studied in 56 patients aged from 28 to 80 years with trigeminal neuralgia. To study the psychological status, such scales as Hospital Anxiety and Depression Scale, Pain Catastrophizing Scale and Patient's Subjective Assessment of Treatment Effectiveness Scale (PSATES) were used with special attention paid to presence of suicidal thoughts.

RESULTS

The signs of anxiety were clinically significant in 7%, absent - in 66 % of the patients. There were no signs of depression in 63 % of cases, while 7% of the patients suffered from clinically significant depression. Pain catastrophizing was observed in 76.8 % of patients. None of the patients rated the intervention as "excellent" on PSATES despite the complete pain relief in the majority of patients (78.6 %), and only 16.1 % of the patients rated it as "good". The aggravation factor had a significant influence on this evaluation (p = 0.01).

CONCLUSIONS

General psychological status assessment can be used to objectify the indicators of the questionnaires and pain scales, as well as to determine the treatment tactics in this group, especially when it is necessary to clarify indications for an intervention and to decide on its proper time. Regardless of the outcome, the patients need time and psychological help for social adaptation due to changes in their social status.

Burden of illness of trigeminal neuralgia among patients managed in a specialist center in England

Background

Trigeminal neuralgia (TN) causes severe episodic, unilateral facial pain and is initially treated with antiepileptic medications. For patients not responding or intolerant to medications, surgery is an option.

Methods

In order to expand understanding of the pain-related burden of illness associated with TN, a cross-sectional survey was conducted of patients at a specialist center that utilizes a multidisciplinary care pathway. Participants provided information regarding their pain experience and treatment history, and completed several patient-reported outcome (PRO) measures.

Results

Of 129 respondents, 69/128 (54%; 1 missing) reported no pain in the past 4 weeks. However, 84 (65%) respondents were on medications, including 49 (38%) on monotherapy and 35 (27%) on polytherapy. A proportion of patients had discontinued at least one medication in the past, mostly due to lack of efficacy (n = 62, 48%) and side effects (n = 51, 40%). A total of 52 (40%) patients had undergone surgery, of whom 30 had microvascular decompression (MVD). Although surgery, especially MVD, provided satisfactory pain control in many patients, 29% of post-surgical patients reported complications, 19% had pain worsen or stay the same, 48% were still taking pain medications for TN, and 33% reported new and different facial pain.

Conclusions

In most PRO measures, respondents with current pain interference had poorer scores than those without pain interference. In the Patient Global Impression of Change, 79% expressed improvement since beginning of treatment at this clinic. These results indicate that while the multidisciplinary approach can substantially alleviate the impact of TN, there remains an unmet medical need for additional treatment options.

Frequency-specific alterations in cortical rhythms and functional connectivity in trigeminal neuralgia

Neuroimaging studies have shown that chronic pain is maladaptive and influences brain function and behavior by altering the flexible cerebral information flow. We utilized power spectral analysis to investigate the impact of classic trigeminal neuralgia (TN) on the oscillation dynamics of intrinsic brain activity in humans. The amplitude of low-frequency fluctuations (ALFF) and fractional ALFF (fALFF) were measured in 29 TN patients and 34 age- and sex-matched healthy controls (HCs) via resting-state functional MRI (R-fMRI). Two different frequency bands (slow-5: 0.01-0.027 Hz; slow-4: 0.027-0.073 Hz) were analyzed. Differences in blood oxygen level-dependent (BOLD) signal fluctuations and related resting-state functional connectivity (rsFC) between the TN patients and HCs were identified. The TN patients had reduced ALFF/fALFF in the posterior cingulate cortex (PCC), left insula, left dorsolateral prefrontal cortex (DLPFC), left putamen and bilateral temporal lobe, exclusively in the frequency of the slow-5 band. Whole brain rsFC analyses with these six different regions as seeds revealed two weaker circuits including the PCC-medial prefrontal cortex (mPFC) and DLPFC-hippocampus circuits, indicating abnormal interactions with the default mode network (DMN) in TN patients. The functional connectivity between the default-mode regions (mPFC and PCC) in the slow-5 band tracked pain intensity. Together, our results provide novel insights into how TN disturbs the cortical rhythms and functional interactions of the brain. These insights may have implications for the understanding and treatment of brain dysfunction in chronic pain patients, including TN patients.

Pain and Psychological Distress: Effect of Microvascular Decompression on Sleep Disorders and Obsessions in Trigeminal Neuralgia

Objective  This study was aimed to investigate the effects of microvascular decompression (MVD) on sleep disorders and obsessions in trigeminal neuralgia. Methods  Clinical data from 115 patients with trigeminal neuralgia treated with MVD from August 1, 2017 to May 31, 2018 at Jining First People's Hospital were analyzed retrospectively. The preoperative and postoperative risk factors for sleep disorders and obsessions, as well as the effects of MVD on sleep disorders and obsessions, were examined. Results  In 115 patients, there were significant differences in preoperative sleep disorders associated with sex, monthly household income, pain in multiple branches, visual analog scale (VAS) score, and Self-Rating Depression Scale (SDS) score ( p  < 0.05). Preoperative obsessions were significantly different according to age, gender, pain in multiple branches, monthly household income, VAS score, and Self-Rating Anxiety Scale (SAS) score groups ( p  < 0.05). A 1-year recurrence was positively correlated with sleep disturbance (odds ratio = 3.829) and obsessions (odds ratio = 4.507). In addition, the results revealed a negative correlation between the manipulation of trigeminal neuralgia and postoperative sleep disorders ( B  ≥ 1.043). Moreover, there was a significant difference in sleep disorders and obsessions before and 1 year after MVD ( p  < 0.05). Conclusion  For patients with trigeminal neuralgia, pain caused by sleep and obsession disorders should be examined early to identify an effective solution. Moreover, MVD, as a first treatment, is valuable for improving the physiological and psychological prognosis of patients.

Trigeminal Neuralgia: Basic and Clinical Aspects

The trigeminal nerve is the largest of all cranial nerves. It has three branches that provide the main sensory innervation of the anterior two-thirds of the head and face. Trigeminal neuralgia (TN) is characterized by sudden, severe, brief, and stabbing recurrent episodes of facial pain in one or more branches of the trigeminal nerve. Pain attacks can occur spontaneously or can be triggered by non-noxious stimuli, such as talking, eating, washing the face, brushing teeth, shaving, a light touch or even a cool breeze. In addition to pain attacks, a proportion of the patients also experience persistent background pain, which along with autonomic signs and prolonged disease duration, represent predictors of worse treatment outcomes. It is now widely accepted that the presence of a neurovascular compression at the trigeminal root entry zone is an anatomic abnormality with a high correlation with classical TN. However, TN may be related to other etiologies, thus presenting different and/or additional features. Since the 1960s, the anticonvulsant carbamazepine is the drug of choice for TN treatment. Although anti-epileptic drugs are commonly used to treat neuropathic pain in general, the efficacy of carbamazepine has been largely limited to TN. Carbamazepine, however, is associated with dose-limiting side-effects, particularly with prolonged usage. Thus, a better understanding and new treatment options are urgently warranted for this rare, but excruciating disease.

Long-Term Beneficial Effects of Acupuncture with Reduced Risk of Depression Development Following Trigeminal Neuralgia: A Nationwide Population-Based Cohort Study

BACKGROUND

Existing evidence has shown that patients with trigeminal neuralgia (TN) have a higher risk of developing depression than the normal population. Clinically, acupuncture has been widely used to alleviate pain in TN. However, few studies have explored the use of acupuncture to prevent depression in TN. Therefore, this study aimed to apply national real-world data to investigate the long-term effect of acupuncture on the risk of depression in patients with TN.

METHODS

We recruited participants with newly diagnosed TN from the Taiwanese National Health Insurance Research Database between January 1, 2000 and December 31, 2010, and categorized them into either the acupuncture cohort or non-acupuncture cohort using the 1:1 propensity score-matched method. All patients in the two cohorts were followed up until the end of 2013. Cox proportional hazards regression analysis was used to compare the incidence of depression between the two cohorts.

RESULTS

In total, 776 patients with newly diagnosed TN in each cohort with similar baseline characteristics were enrolled in the study. The acupuncture cohort had a reduced risk of depression compared to the non-acupuncture cohort (adjusted hazard ratio, 0.47; 95% confidence interval, 0.31-0.70). Kaplan-Meier analysis also revealed that the cumulative incidence of depression was significantly lower in the acupuncture cohort during the 13-year follow-up period (Log rank test, p < 0.001). In particular, the beneficial effect of acupuncture was a decrease in the risk of depression among TN patients aged 50-69 years who had also used carbamazepine.

CONCLUSION

This study demonstrated that acupuncture is associated with a reduction in the risk of depression during long-term follow-up in patients with TN. The results provide new insights for clinical practitioners as well as for health resource allocation.

The role of a clinical nurse specialist in managing patients with trigeminal neuralgia

Background and Aims

Patients with trigeminal neuralgia (TN) can be overwhelmed with information they are given when first seen in a specialist secondary care clinic. The purpose of this study is to evaluate the extent to which a telephone service provided by the clinical nurse specialist (CNS) with independent prescribing rights improves patient management and satisfaction and reduces costs.

Methods

All patients with a diagnosis of TN who used the CNS telephone service in 2015 were contacted by two medical students (independent observers) using a semi-structured questionnaire. Patients who could not be contacted were sent the same questionnaire and asked to return it by post.

Results

Fifty-two patients were identified and 34 replied to a telephone call and 10 to a questionnaire, response rate 85%. Overall, 61% of patients rated their care outstanding or excellent. Four patients could not remember their consultation, others had used it on multiple occasions. Reasons for the consultation were pain management 50%, changeover of drugs 25%, advice about drug schedules 17%, and dealing with side effects 8%. The number of general practitioner (GP) consultations decreased as a result of this service. Patients suggested that the service should be available more than once a week.

Conclusion

The CNS telephone service cut down on the number of outpatient appointments needed and reduced travel costs. Patients were appreciative that the CNS was in contact with GPs and this ensured prescriptions were filled in a timely manner and strengthen links with practices.

Trigeminal Neuralgia

Trigeminal neuralgia is one of the most severe facial pains that patients can experience. This unpredictable, episodic pain, mostly unilateral in the distribution of the trigeminal nerve, results in recurrent shooting pain lasting for seconds to minutes. It is light touch provoked and therefore prevents patients from eating and touching their face, and so has a significant impact on quality of life. Patients often consult a dentist because it usually presents like dental pain. Dentists need to avoid irreversible dental treatment. Response to carbamazepine is good but tolerability is poor. Surgical options are available and are generally successful. Patients can gain further information from a patient support group, such as Trigeminal Neuralgia Association UK.

CPD/Clinical Relevance: Although rare, trigeminal neuralgia patients often present to dentists who therefore need to recognize it as a non-dental cause of pain in order to avoid irreversible dental treatment.

Trigeminal neuralgia: Comparison of characteristics and impact in patients with or without multiple sclerosis

OBJECTIVES

The commonest secondary cause for trigeminal neuralgia (TN) is multiple sclerosis (MS) and little is known about this group of patients in terms of their presentation and treatments. We compared patients with TN and MS (pwTNMS) with a cohort of patients with primary TN, who had been referred to the same specialist unit, both in terms of characteristics and impact on quality of life at the time of their first assessment.

METHODS

Using a prospective patient database we extracted key clinical data and results from psychometrically tested questionnaires of 26 pwTNMS and compared them to an age and gender-matched set of 68 patients with primary TN.

RESULTS

Our findings suggest that pwTNMS exhibit a more severe clinical phenotype than primary TN. Prior to referral, pwTNMS are more likely to have used more healthcare services and undergone more neurosurgical interventions. Strikingly, pwTNMS exhibit reduced lengths and duration of remission periods and fewer identifiable triggers. Furthermore, pwTNMS report significant impact on quality of life comparable to those in primary TN, scoring highly in measures of anxiety, depression, and catastrophizing, but also report greater sleep disturbance, and overall interference in activities of daily living.

CONCLUSIONS

pwTNMS have a more intractable TN, one which may necessitate a more complex approach to treatment, earlier referral to secondary care and an extensive assessment of mental health. Quality of life in pwTNMS is severely affected by both their MS and their TN, suggesting management should occur in specialist centres with access to a multidisciplinary team.

Canadian neurosurgeons' views on medical assistance in dying (MAID): a cross-sectional survey of Canadian Neurosurgical Society (CNSS) members

BACKGROUND

The Supreme Court of Canada removed the prohibition on physicians assisting in patients dying on 6 February 2015. Bill C-14, legalising medical assistance in dying (MAID) in Canada, was subsequently passed by the House of Commons and the Senate on 17 June 2016. As this remains a divisive issue for physicians, the Canadian Neurosurgical Society (CNSS) has recently published a position statement on MAID.

METHODS

We conducted a cross-sectional survey to understand the views and perceptions among CNSS members regarding MAID to inform its position statement on the issue. Data was collected from May to June 2016.

RESULTS

Of the 300 active membes of the CNSS who recevied the survey, 89 respondents completed the survey, 71% of whom were attending neurosurgeons and 29% were neurosurgery residents. Most respondents,74.2%, supported the right of physicians to participate in MAID with 7.8% opposing. 37% had current patients in their practice fitting the criteria for MAID. 23.6% had been asked by patients to assist with MAID, but only 11% would consider personally providing it. 84% of neurosurgeons surveyed supported the physicians' right to conscientious objection to MAID while 21% thought attending surgeons should be removed from the inquiry and decision-making process. 43.8% agreed that the requirment to refer a patient to a MAID service should be mandatory. Glioblastoma multiforme (65%), quadriplegia/quadriparesis secondary to spinal tumour/trauma (54%) and Parkinson's disease (24%) were the most common suggested potential indications for MAID among the neurosurgical population.

CONCLUSIONS

Our results demonstrate that most neurosurgeons in Canada are generally supportive of MAID in select patients. However, they also strongly support the physicians' right to conscientious objection.

Awake microvascular decompression with fat-teflon sandwich technique: Clinical implications of a novel approach for cranial nerve neuralgias

Re-appearance of trigeminal neuralgia (TN) pain following microvascular decompression (MVD) is a challenging issue. A selective ablation with MVD provides the best response in such recurrences. The absence of intra-operative indicator for immediate correction of sub-optimal decompression is the primary factor for failure. We analysed the effectiveness and safety of awake MVD in minimizing failure, by tailoring the procedure according to intra-operative response with re-exploration or additional procedure like internal neurolysis in the same setting, especially in patients without vascular compression and those unfit for General Anesthesia (GA). The prospective study from June 2016 to June 2017 includes one glossopharyngeal neuralgia (GPN) and 6 trigeminal neuralgia (TN). Five cases responded with immediate complete pain relief but in 2 cases, incomplete pain relief resulted in alteration of intraoperative decision. In one case, a partial pain relief, mandated an additional internal neurolysis in the same setting, resulting in complete pain relief while in the other, re-exploration revealed a hidden venous conflict, not identified on MRI following which an additional IN was performed. All cases were followed up with BNI PIS for a minimum of one year without recurrence. Awake MVD is safe and reliable intraoperative neurophysiological prognostic marker of immediate pain relief and provides a window for an immediate correction of sub-optimal decompression with Internal Neurolysis when needed, in the same setting, especially in neuroimaging negative and elderly cases unfit for GA. It has the potential to reduce the rate of re-intervention and increase the overall effectiveness of MVD by specifically ameliorating the pain burden and quality of life.

Correlation between nerve atrophy, brain grey matter volume and pain severity in patients with primary trigeminal neuralgia

BACKGROUND

Recent neuroimaging studies have reported grey matter alterations in primary trigeminal neuralgia patients. However, few studies have focused on quantitative measurements of trigeminal nerves and the interaction between trigeminal nerve volume and brain morphology, particularly grey matter volume. In this study, we investigated the link between trigeminal nerves and grey matter volume changes in primary trigeminal neuralgia patients compared to healthy controls. Moreover, we explored the association of structure of trigeminal nerves and grey matter to collected pain clinical variables.

METHODS

Eighty participants (40 patients and 40 controls) were recruited for the study. All participants underwent MRI sessions and clinical pain assessment. Trigeminal nerve volume and whole brain grey matter volume were evaluated using quantitative imaging techniques. Sensory and affective pain rating indices were assessed using the visual analog scale and short-form McGill Pain Questionnaire. Mediation analysis was conducted to investigate the relationship between clinical pain variables and volumetric changes in trigeminal nerves and grey matter.

RESULTS

Decreased trigeminal nerve volume was detected in primary trigeminal neuralgia patients compared to controls. Additionally, reduced grey matter volume was found in several regions associated with pain in primary trigeminal neuralgia subjects, including the insula, secondary somatosensory cortex, hippocampus, dorsal anterior cingulate cortex, precuneus, and several areas of the temporal lobe. Mediation analysis revealed that decreased trigeminal nerve volume drove grey matter volume abnormality of the left insula, and further led to increased pain ratings.

CONCLUSION

This study showed a predominantly direct effect of trigeminal nerve atrophy on clinical pain variables in primary trigeminal neuralgia patients, providing new insight into the pathophysiology of the disease.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02713646.

Dysregulation of Pain- and Emotion-Related Networks in Trigeminal Neuralgia

Classical trigeminal neuralgia (TN) is a severe neuropathic facial pain disorder associated with increased risks of anxiety and depression. Converging evidence suggests that chronic pain pathophysiology involves dysfunctional pain-related and emotion-related networks. However, whether these systems are also among the culprit networks for TN remains unclear. Here, we aimed to assess TN-related anatomical and functional brain anomalies in pain-related and emotion-related networks. We investigated differences in gray matter (GM) volume and the related resting-state functional connectivity (rsFC) between 29 classical TN patients and 34 matched healthy controls. Relationships between brain measurement alterations, clinical pain and emotional states were identified. A longitudinal observation was further conducted to determine whether alterations in the brain could renormalize following pain relief. Reduced GM volumes in the bilateral amygdala, periaqueductal gray (PAG) and right insula were found in TN patients compared with healthy control subjects. Whole-brain rsFC analyses with the four above-mentioned anatomical regions as seeds identified three significantly altered functional circuits, including amygdala-DLPFC, amygdala-mPFC and amygdala-thalamus/putamen circuitry. The amygdala-DLPFC and amygdala-mPFC circuits were associated with clinical pain duration and emotional state ratings, respectively. Further longitudinal analysis found that rsFC strength abnormalities in two fronto-limbic circuits (left amygdala/left DLPFC and right amygdala/right PFC) were resolved after pain relief. Together, structural and functional deficits in pain-related and emotion-related networks were associated with TN patients, as demonstrated by our multimodal results. Pain relief had protective effects on brain functional connectivity within fronto-limbic circuits. Our study provides novel insights into the pathophysiology of TN, which may ultimately facilitate advances in TN intervention.

The psychosocial impact of orofacial pain in trigeminal neuralgia patients: a systematic review

Trigeminal neuralgia (TN) is characterized by sharp, electric shock-like pain, which can be triggered by trivial stimuli. Although medical and surgical treatments are available for TN, some patients experience refractory pain, which has a significant impact on their quality of life. The aim of this systematic review was to determine the psychosocial impact of orofacial pain in patients with diagnosed TN. A search was initiated in three electronic databases (Embase, MEDLINE, PubMed) to identify potential studies for inclusion in the review. All types of study published in English that reported psychosocial measures using validated psychometric questionnaires were included. A total of 585 articles were retrieved from the search. These were screened thoroughly, leading to the selection of 13 articles for data extraction and final analysis. The results show the chronic overwhelming nature of TN, with pain levels varying from mild to severe. Psychometric scores indicated mild to moderate depression, moderate to severe anxiety, and moderate to severe functional limitation of daily life activities in TN patients. Therefore, psychological support within a multidisciplinary team is recommended for TN patients to help them cope better with their chronic disorder and to improve the efficacy of treatment.

Evaluating the impact of trigeminal neuralgia

Patients with idiopathic trigeminal neuralgia (TN) were categorised into 3 subtypes (n = 225). Group 1 (n = 155, 68.9%) had TN without concomitant pain, group 2 (n = 32, 14.2%) had TN with intermittent concomitant pain, and group 3 (n = 39, 16.9%) had TN with autonomic symptoms. We tested 2 hypotheses: (1) that different pain profiles would be associated with the different groups; (2) that the severe pain associated with TN would impact negatively on activities of daily living and thereby result in disability as defined by the World Health Organisation. A different pain profile was found across the groups. We obtained unequivocal evidence that TN causes disability with up to 45% of patients being absent from usual daily activities 15 days or more in the past 6 months. On the Hospital Anxiety and Depression Scale, 35.7% patients had mild-to-severe depression and over 50% were anxious. The Pain Catastrophizing Scale showed that 78% of patients had considerable negative thoughts with scores >20 and a mean score of 36.4. Prior to referral, only 54% had been prescribed carbamazepine while opioids had been prescribed in 14.6% of the patients. Prior to referral, over 80% had already been to 1 specialist centre which had not provided appropriate management. Patients with TN report varied characteristics but all result in some degree of psychosocial disability especially before adequate therapy is attained.

Amplified parabrachial nucleus activity in a rat model of trigeminal neuropathic pain

The parabrachial (PB) complex mediates both ascending nociceptive signaling and descending pain modulatory information in the affective/emotional pain pathway. We hypothesized that PB hyperactivity influences chronic pain behavior after trigeminal nerve injury in rats. Following induction of neuropathic pain using the chronic constriction injury of the infraorbital nerve (CCI-ION) model, rats displayed spontaneous markers of pain and mechanical hyperalgesia extending beyond the receptive field of the injured nerve. PB neurons recorded from rats with CCI-ION displayed amplified activity, manifesting as significantly longer responses to sensory stimuli, compared to shams. These findings suggest that chronic neuropathic pain involves PB hyperactivity.

Impact of pain and postoperative complications on patient-reported outcome measures 5 years after microvascular decompression or partial sensory rhizotomy for trigeminal neuralgia

Background

Microvascular decompression (MVD) and partial sensory rhizotomy (PSR) provide longstanding pain relief in trigeminal neuralgia (TN). Given their invasiveness, complications can result from such posterior fossa procedures, but the impact of these procedures and their complications on patient-reported outcome measures (PROM), such as quality of life and distress, are not well established.

Method

Five years after surgery, patients who underwent first MVD or PSR for TN at one institution, between 1982 and 2002, were sent a self-completion assessment set containing a range of PROMs: the Short Form-12 (SF-12) questionnaire to assess quality of life, the Hospital Anxiety and Depression Scale (HADS) to assess distress, and a questionnaire containing questions about postoperative complications, their severity and impact on quality of life. These findings and demographic data were compared between MVD and PSR.

Results

One hundred and eighty-one of 245 (73.9%) patients after first MVD and 49 of 60 (81.7%) after PSR responded, and were included in analyses. The mean SF-12 scores of patients after MVD and PSR at five-year follow-up were significantly lower than English age-matched norms. Though there were no differences in SF-12 physical or mental component scores between the two procedures, patients after PSR were more likely to have case-level anxiety (RR = 3.3; 95% CI, 1.1–10.5; p = 0.03), had more postoperative complications, and of greater severity, including pain (RR = 2.52; 95% CI, 1.5–4.1; p < 0.001), numbness (RR = 5.9; 95% CI, 3.8–9.2; p < 0.001), burning sensations (RR = 3.0; 95% CI, 1.5–5.8; p = 0.001) and difficulty in eating (RR = 17.1; 95% CI, 5.6–53.1; p < 0.001), and these had a larger impact on quality of life for PSR compared to MVD.

Conclusions

The quality of life 5 years after MVD or PSR is poorer than in the general population and associated with postoperative complications such as pain, numbness, burning sensation and difficulty in eating. These complications are commoner after PSR than MVD, and this is associated with anxiety in PSR patients at five-year follow-up. However, these differences are not reflected by quality of life scores. Outcome measures need to incorporate patient experience after treatment for TN, and represent patient priorities for quality of life.

Electronic supplementary material

The online version of this article (10.1007/s00701-017-3350-6) contains supplementary material, which is available to authorized users.