Measurement of Trigeminal Neuralgia Pain

Factors associated with outcomes following microvascular decompression for the treatment of primary trigeminal neuralgia in adults: a systematic review and meta-analysis

This study aimed to evaluate pain assessment strategies and factors associated with outcomes after microvascular decompression for the treatment of primary trigeminal neuralgia in adults. We conducted a systematic review and meta-analysis of English, Spanish, and French literature. We searched three databases, PubMed, Ovid, and EBSCO, from 2010 to 2022 and selected studies including patients with primary trigeminal neuralgia, clear pain assessment, and pain outcomes. Population means and standard deviations were calculated. Studies that included factors associated with postoperative outcomes were included in the meta-analysis. A total of 995 studies involving 5673 patients with primary trigeminal neuralgia following microvascular decompression were included. Patients with arteries compressing the trigeminal nerve demonstrated optimal outcomes following microvascular decompression (odds ratio [OR]= 0.39; 95% confidence interval [CI] = 0.19-0.80; X2 = 46.31; Dof = 15; I2 = 68%; P = < 0.0001). Conversely, when comparing arterial vs venous compression of the trigeminal nerve (OR = 2.72; 95% CI = 1.16-6.38; X2 = 23.23; Dof = 10; I2 = 57%; P = 0.01), venous compression demonstrated poor outcomes after microvascular decompression. Additionally, when comparing single-vessel vs multiple-vessel compression (OR = 2.72; 95% CI = 1.18-6.25; X2 = 21.17; Dof = 9; I2 = 57%; P = 0.01), patients demonstrated unfavorable outcomes after microvascular decompression. This systematic review and meta-analysis evaluated factors associated with outcomes following microvascular decompression (MVD) for primary trigeminal neuralgia (PTN). Although MVD is an optimal treatment strategy for PTN, a gap exists in interpreting the results when considering the lack of evidence for most pain assessment strategies.

Pain Outcomes Following Endoscopic Microvascular Decompression for Trigeminal Neuralgia Based on Vascular Compression Type

Background  Arterial compression of the trigeminal nerve at the root entry zone has been the long-attributed cause of compressive trigeminal neuralgia despite numerous studies reporting distal and/or venous compression. The impact of compression type on patient outcomes has not been fully elucidated. Objective  We categorized vascular compression (VC) based on vessel and location of compression to correlate pain outcomes based on compression type. Methods  A retrospective video review of 217 patients undergoing endoscopic microvascular decompression for trigeminal neuralgia categorizing VC into five distinct types, proximal arterial compression (VC1), proximal venous compression (VC2), distal arterial compression (VC3), distal venous compression (VC4), and no VC (VC5). VC type was correlated with postoperative pain outcomes at 1 month ( n  = 179) and last follow-up (mean = 42.9 mo, n  = 134). Results  At 1 month and longest follow-up, respectively, pain was rated as "much improved" or "very much improved" in 89 69% of patients with VC1, 86.6 and 62.5% of patients with VC2, 100 and 87.5% of patients with VC3, 83 and 62.5% of patients with VC4, and 100 and 100% of patients with VC5. Multivariate analysis demonstrated VC4 as a significant negative of predictor pain outcomes at 1 month, but not longest follow-up, and advanced age as a significant positive predictor. Conclusion  The degree of clinical improvement in all types of VC was excellent, but at longest follow-up VC type was not a significant predictor out outcome. However distal venous compression was significantly associated with worse outcomes at 1 month.

Comparison of microvascular decompression, percutaneous radiofrequency rhizotomy, and stereotactic radiosurgery in the treatment of trigeminal neuralgia: A long term quasi-experimental study

BACKGROUND

Microvascular decompression (MVD), radiofrequency rhizotomy (RFR), and stereotactic radiosurgery (SRS) are surgical techniques frequently used in the treatment of idiopathic trigeminal neuralgia (TN), although the results reported for each of these are diverse.

OBJECTIVE

This study aimed to compare long-term pain control obtained by MVD, SRS, and RFR in patients with idiopathic TN.

METHODS

To compare the results obtained by MVD, SRS, and RFR we chose a quasi-experimental, ambispective design with control groups but no pretest. A total of 52 participants (MVD n = 33, RFR n = 10, SRS n = 9) were included. Using standardized outcome measures, pain intensity, pain relief, quality of life, and satisfaction with treatment were assessed by an independent investigator. The TREND statement for reporting non-randomized evaluations was applied. Clinical outcomes were evaluated at the initial postoperative period and at 6 months, 1, 2, 3, 4, and 5 years postoperatively.

RESULTS

MVD has shown better results in pain scales compared to ablative procedures. Significant differences between groups were found regarding pain intensity and pain relief at the initial postoperative period (p < 0.001) and 6 months (p = 0.022), 1 year (p < 0.001), 2 years (p = 0.002), and 3 years (p = 0.004) after the intervention. Those differences exceeded the thresholds of the minimal clinically important difference. A higher percentage of patients free of pain was observed in the group of patients treated by MVD, with significant differences at the initial postoperative period (p < 0.001) and 6 months (p = 0.02), 1 year (p = 0.001), and 2 years (p = 0.04) after the procedure. Also, a higher risk of pain recurrence was observed in the RFR and SRS groups (HR 3.15, 95% CI 1.33-7.46; p = 0.009; and HR 4.26, 95% CI 1.77-10.2; p = 0.001, respectively) compared to the MVD group. No significant differences were found in terms of quality of life and satisfaction with treatment. A higher incidence of complications was observed in the MVD group.

CONCLUSION

Concerning pain control and risk of pain recurrence, MVD is superior to RFR and SRS, but not in terms of quality of life, satisfaction with treatment, and safety profile.

The long-term outcome of CT-guided radiofrequency ablation of the peripheral branches of the trigeminal nerve in trigeminal neuralgia

Radiofrequency thermocoagulation (RFTC) of the peripheral branches of the trigeminal nerve has been used for trigeminal neuralgia. However, the long-term outcomes of radiofrequency thermocoagulation have not been established. To evaluate the long-term efficacy of RFTC of peripheral branches in patients with refractory trigeminal neuralgia. A retrospective cohort study was conducted in a comprehensive medical center in China. Patients who underwent radiofrequency thermocoagulation of peripheral branches for refractory trigeminal neuralgia from May 2014 to March 2021 were included for analysis. A total of 84 patients with refractory trigeminal neuralgia underwent 105 procedures. BNI I-II which represents treatment success was achieved in 76/84 (90%) patients and 93/105 (89%) procedures. During follow-up, BNI I and II were maintained in 64/76 (84%), 40/73 (55%), 20/67 (30%), 17/65 (26%), 12/61 (20%), and 8/58 (14%) of patients at 1, 2, 3, 4, 5, and 6 years, after the first procedure, respectively. For all the 105 procedures, BNI I and II were maintained in 68/93 (73%), 41/89(46%), 22/82(27%), 15/79 (19%), 8/74 (11%), and 3/72 (4%) at 1, 2, 3, 4, 5, and 6 years, respectively. There is no significant difference between the first and repeat thermocoagulation in terms of immediate (90% vs. 81%, P=0.140) and long-term efficacies (24 months vs.18 months, P=0.266). Radiofrequency thermocoagulation resulted in better long-term outcomes in patients with typical purely paroxysmal pain (24 months vs. 11 months, P=0.033). Radiofrequency ablation of the peripheral branches of the trigeminal nerve might be a safe and effective method in the treatment of refractory trigeminal neuralgia.

The Therapeutic Effect of Botulinum Toxin Type A on Trigeminal Neuralgia: Are There Any Differences between Type 1 versus Type 2 Trigeminal Neuralgia?

BACKGROUND

Botulinum toxin type A is an effective treatment for trigeminal neuralgia. Moreover, its efficacy in type 2 trigeminal neuralgia and comparative studies between type 1 and type 2 trigeminal neuralgia (TN) still need to be improved.

METHODS

We treated 40 TN patients with onabotulinumtoxinA; 18 had type 1 TN, and 22 had type 2 TN. We compared the baseline pain score with the Visual Analogue Scale (VAS) and paroxysm frequency (number per week) at the baseline with those obtained at 1-month and 3-month follow-ups. Nonetheless, we compared the baseline Penn Facial Pain Scale with the scores obtained at the 1-month follow-up.

RESULTS

BoNT/A effectively reduced pain intensity and frequency at the 1-month and 3-month follow-ups. Moreover, the type 1 TN and type 2 TN groups had baseline pain scores of 7.8 ± 1.65 and 8.4 ± 1.1, respectively. Pain significantly improved (p < 0.001) in both groups to 3.1 ± 2.3 (type 1 TN) and 3.5 ± 2.3 (type 2 TN) at the 1-month follow-up and to 3.2 ± 2.5 (type 1 TN) and 3.6 ± 2.5 (type 2 TN) at the 3-month follow-up. There was no difference between the two groups (p 0.345). The baseline paroxysm frequencies (number per week) were 86.7 ± 69.3 and 88.9 ± 62.2 for the type 1 and type 2 TN groups, respectively; they were significantly reduced in both groups at the 1-month and 3-month follow-ups without significant differences between the two groups (p 0.902). The Pain Facial Pain Scale improved at the 1-month follow-up, and no significant differences were found between the two groups. There was a strong correlation between background pain and paroxysm pain intensity (r 0.8, p < 0.001).

CONCLUSIONS

Botulinum toxin type A effectively reduced the pain, paroxysm frequency, and PFPS scores of type 1 and type 2 trigeminal neuralgia patients without statistically significant differences. Facial asymmetry was the only adverse event.

The Comparison of General Characteristics and Early and Late Post-intervention Results in Patients With Trigeminal Neuralgia Secondary to Multiple Sclerosis and Idiopathic Trigeminal Neuralgia Treated With Radiofrequency Thermocoagulation

Aim The aim of this study was to investigate possible differences (in terms of demographic structure, disease history, complaints, clinical findings, early and late treatment outcomes, and complications) between patients with idiopathic trigeminal neuralgia (ITN) and trigeminal neuralgia (TN) secondary to multiple sclerosis (MS) who were admitted to our clinic and underwent radiofrequency (RF) thermocoagulation procedure. Materials and methods Patients who underwent percutaneous radiofrequency thermocoagulation with a diagnosis of trigeminal neuralgia by a single neurosurgeon in a single neurosurgery clinic between January 2005 and January 2020 were included in this study. Patients were divided into two groups: idiopathic trigeminal neuralgia and trigeminal neuralgia secondary to multiple sclerosis (MSTN) according to their diagnosis. In our study, 215 TN patients who underwent 286 procedures were included. These patients were categorized according to age, sex, involved side, pain localization, and pain history. Postoperative complications were determined after each intervention. The early and late results of all interventions were evaluated, and the results were compared between both groups. All results were statistically analyzed. Results Considering the age of the patients, the mean age of the idiopathic group was higher than the multiple sclerosis group (58.18>49.46). In terms of the side of pain, bilateral involvement was significantly more common in the MS secondary group (1.48%<30.77%). There was no significant difference between the early results of both groups. In terms of remission periods, the pain-free period in the MS secondary group was significantly shorter than in the idiopathic group (mean value in months, 30.87>23.81). Conclusion The radiofrequency thermocoagulation of the trigeminal nerve is a highly effective, low-complication, reproducible procedure for trigeminal neuralgia, but the search for ways to improve the efficacy of treatment in MS patients should continue.

Online dynamic nomogram for predicting pain recurrence after microvascular decompression in trigeminal neuralgia

Trigeminal neuralgia (TN) is one of the most common causes of facial pain. Microvascular decompression (MVD) is the first-choice surgical treatment. The present study aimed to develop a novel practical assessment system based on preoperative clinical and imaging factors for clinicians to predict the likelihood of pain recurrence following MVD in TN. A total of 56 patients with primary unilateral TN who underwent MVD were retrospectively analyzed. Patients were followed up to observe pain recurrence 1 year after MVD. An online dynamic nomogram was constructed for predicting the probability of pain recurrence after MVD in patients with TN based on multivariate logistic model. The concordance index (C-index) and receiver operating characteristic (ROC) were used to measure model discrimination. Bootstrap resampling was used for internal validation of the model and calibration curve was constructed. Decision curve analysis (DCA) was used to assess clinical applicability. Factors such as numeric rating scale (to score pain degree of patients with TN), response to neuroanalgesic drugs and neurovascular contact on magnetic resonance imaging were independent risk factors affecting the pain recurrence rate (all P<0.05). C-index was 0.973 (95%CI, 0.938-1.000) and the area under the ROC was 0.973 (95%CI, 0.938-1.000). Calibration curve with a 1,000 bootstrap resampling showed a good fit between dynamic nomogram prediction and actual observations. The DCA showed that at a threshold probability between 0 and 100%, this model can achieve a greater net benefit than if all patients had surgery or none had surgery. In conclusion, this online dynamic nomogram reliably predicted risk of pain recurrence in patients with TN following MVD.

Botulinum Toxin Type A for the Treatment of Auriculotemporal Neuralgia-A Case Series

Auriculotemporal neuralgia is a rare pain disorder in which anesthetic nerve blockade is usually effective but not always resolutive. Botulinum toxin type A has proven to be effective in treating neuropathic pain, and patients with auriculotemporal neuralgia could also benefit from this treatment. We described nine patients with auriculotemporal neuralgia treated with botulinum toxin type A in the territory of auriculotemporal nerve innervation. We compared the basal NRS and Penn facial pain scale scores with those obtained 1 month after BoNT/A injections. Both Penn facial pain scale (96.67 ± 24.61 vs. 45.11 ± 36.70, p 0.004; mean reduction 52.57 ± 36.50) and NRS scores (8.11 ± 1.27 vs. 4.22 ± 2.95, p 0.009; mean reduction 3.89 ± 2.52) improved significantly at one month after treatment. The mean duration of the effect of BoNT/A on pain was 95.00 ± 53.03 days and no adverse effects were reported.

Differences between Maximum Tongue Force in Women Suffering from Chronic and Asymptomatic Temporomandibular Disorders-An Observational Study

Background: Temporomandibular disorders are craniofacial disorders characterized by the presence of chronic pain in masticatory muscles, with higher incidence in the women population. There is little research that has studied tongue force related to temporomandibular disorders, but there are a lot of studies that have demonstrated the impact of tongue force in vital functions, such as chewing, swallowing, phonation, or breathing. According to this, the aim of this study was to compare the maximum force of the tongue between females with chronic temporomandibular disorders and asymptomatic females. We also wanted to establish whether any relationship existed between the pain and fatigue versus the maximum force developed in females with chronic temporomandibular disorders. Material and methods: A cross-sectional study of 67 women between the ages of 18 and 65 years old was performed. The included women were assigned to one of two groups, according to whether they had chronic temporomandibular disorders or not. The procedure was the same for both groups. Outcome measures included the maximum tongue force, intensity of perceived orofacial pain, and intensity of perceived orofacial fatigue. Results: The results showed significant statistical differences for the maximum tongue force measurement between the chronic temporomandibular disorders group and the control group (p < 0.05) for all the movements, except the lip pressure measurement. Furthermore, the analysis revealed significant statistical differences between the intensity of perceived orofacial fatigue between the groups (p < 0.05). Moreover, the data showed no significant correlations between variables. Conclusion: The study found significant differences in maximum tongue force when comparing women with chronic temporomandibular disorders and asymptomatic women (being superior in these). Likewise, we found that the intensity of perceived orofacial fatigue after tongue exercises showed significant differences between groups. However, this study reveals no correlations between the intensity of perceived orofacial pain and fatigue and the maximum tongue force.

How should clinicians assess acute dental pain?: A review

Pain is the most common complaint in the dental field and may have a significant impact on the patients' quality of life. However, objective pain assessment is sometimes difficult, and medical and dental clinicians may encounter cases of pain in the head and neck region, making it difficult to establish differential diagnoses. This study aimed to review acute pain in clinical dentistry at each phase of dental procedures and discuss the current status and issues in the development of acute dental pain assessment methods in the future. Acute pain in clinical dentistry may differ in nature and modifying conditions of pain at each stage: before dental procedures, while visiting dentists, and during and after dental procedures. They are related to actual or potential tissue damage, and may be modified and aided by personal experiences, including psychological and social factors. With respect to the aging and multinational population and pandemic of infectious diseases, significant breakthroughs in the development of new pain scales without verbal descriptions are desirable. Furthermore, it is expected that a new pain scale that can be applied to acute pain in the head and neck regions, including the oral cavity, will be developed.

Delayed pain relief in patients with trigeminal neuralgia following microvascular decompression: A single-central retrospective study

Background

Compared to hemifacial spasm after microvascular decompression (MVD), delayed relief (DR) rarely occurs in patients with trigeminal neuralgia (TGN).

Objective

To analyze the characteristics of post-MVD DR in TGN patients to provide useful clues for the clinical differential diagnosis of postoperative DR.

Methods

The clinical data of all patients with TGN who underwent MVD in our center from January 1, 2016, to December 31, 2020, were reviewed retrospectively.

Results

In 272 TGN MVD patients, DR occurred in nine patients (3.3%) during the follow-up periods of 1–6 years. During surgery, all nine DR-TGN patients were identified as having neurovascular conflicts (NVCs), involving the offending artery (OA) in eight patients (two OAs in two patients) and both an artery and a vein in the other patient. The compression site was near the root entry zone (REZ) in most DR patients (7/9). Delayed relief was relieved in seven patients within 5 days after surgery and within 30 days in the other two patients. No recurrence or serious complications were observed within the mean 4 (1-6)-year follow-up duration.

Conclusion

Delayed relief rarely occurs in TGN patients after MVD. Neurovascular conflicts located at the REZ and NVC of grade III may be two important factors contributing to DR in TGN patients. Delayed relief may occur when the pain gradually improves after the operation and responds effectively to a small dose of carbamazepine. The recurrence rate of TGN seems even lower in such patients.

Fully Endoscopic Microvascular Decompression for Trigeminal Neuralgia: Technical Note Describing a Single-Center Experience

BACKGROUND

Microscopic microvascular decompression (MVD) of the trigeminal nerve is the gold standard surgical treatment for medically refractory classical trigeminal neuralgia. Endoscopy has significantly advanced surgery and provides enhanced visualization of the cerebellopontine angle and its critical neurovascular structures. We present our initial experience of fully endoscopic microvascular decompression (e-MVD).

METHODS

This retrospective case series investigated e-MVD performed from September 2016 to February 2020 at a single institution. Clinical data including presenting symptoms, medications, operative findings, postoperative complications, and outcomes were recorded. The 5-point Barrow Neurological Institute (BNI) pain intensity score was used to quantify patients' pain relief.

RESULTS

During the study period, 25 patients with trigeminal neuralgia (10 males, 15 females; mean [SD] age = 63 [10.4] years) underwent e-MVD. All patients had a preoperative BNI score of V. The left side was affected in 15 patients. Complications occurred in 2 patients: both experienced hearing loss, and one experienced transient facial weakness 7 days after surgery. The facial weakness had resolved by the last follow-up. All patients were completely pain-free (BNI score I) immediately postoperatively. On latest follow-up, 22 patients have remained pain-free, and 3 patients have recurrent pain that is being controlled with medication (BNI score III).

CONCLUSIONS

Our study demonstrated that e-MVD is a safe, possibly effective method of performing MVD with the added benefit of improved visualization of the operative field for the operating surgeon and the surgical team. Larger prospective studies are required to evaluate whether performing e-MVD confers any additional benefits in long-term clinical outcome of patients with trigeminal neuralgia.

Contemporary Analysis of Minimal Clinically Important Difference in the Neurosurgical Literature

BACKGROUND

Minimal clinically important difference (MCID) is determined when a patient or physician defines the minimal change that outweighs the costs and untoward effects of a treatment. These measurements are "anchored" to validated quality-of-life instruments or physician-rated, disease-activity indices. To capture the subjective clinical experience in a measurable way, there is an increasing use of MCID.

OBJECTIVE

To review the overall concept, method of calculation, strengths, and weaknesses of MCID and its application in the neurosurgical literature.

METHODS

Recent articles were reviewed based on PubMed query. To illustrate the strengths and limitations of MCID, studies regarding the measurement of pain are emphasized and their impact on subsequent publications queried.

RESULTS

MCID varies by population baseline characteristics and calculation method. In the context of pain, MCID varied based on the quality of pain, chronicity, and treatment options.

CONCLUSION

MCID evaluates outcomes relative to whether they provide a meaningful change to patients, incorporating the risks and benefits of a treatment. Using MCID in the process of evaluating outcomes helps to avoid the error of interpreting a small but statistically significant outcome difference as being clinically important.

Patient reported outcome measures in trigeminal neuralgia - A systematic review of psychometric performance

BACKGROUND

Trigeminal neuralgia (TN) is a rare condition for which there are multiple treatment options available. To date, there has been difficulty in comparing the outcomes of treatment due to the variety of patient-reported outcome measures (PROMs) and their inadequate psychometric testing. The aim of this review was to assess the psychometric properties of PROMs used to date in TN and make recommendations for their use in future studies.

METHODS

Five electronic databases (MEDLINE, EMBASE, CINAHL Plus, PsycINFO, Health and Psychosocial Instruments) were searched for studies assessing the development of PROMs or their psychometric properties in TN studies. The records obtained were assessed independently by two reviewers for their methodological quality, following guidance from the Consensus-based Standards for the selection of Health Measurement Instruments (COSMIN).

RESULTS

Six studies were identified and information on five PROMs (Brief Pain Inventory Facial (BPI-F), Visual Analogue Scale (VAS), Barrow Neurology Institute Pain Scale (BNI-PS), Penn Facial Pain Scale-Revised (Penn-FPS-R) and Trigeminal Neuralgia Quality of Life Score) were retrieved. The Penn-FPS-R demonstrated moderate quality evidence for sufficient content validity. The BPI-F showed moderate evidence for sufficient internal consistency and structural validity but low evidence for inconsistent content validity. The Trigeminal Neuralgia Quality of Life score showed very low-quality evidence for insufficient content validity, structure validity and responsiveness. No evidence was found on the assessment of any psychometric properties of the VAS and BNI-PS in TN.

CONCLUSION

There is limited evidence of the psychometric performance of patient-reported outcomes for TN and recommendations for their inclusion in future studies cannot be made. The validation of PROMs in TN studies should be a priority in this field of research.

SIGNIFICANCE

This review highlights the knowledge gap in the field of psychometrics of patient reported outcomes measures in the field of TN. Given the unavailability of an objective outcome measure for pain or health related quality of life, psychometrically sound PROMs are essential for assessing medical and surgical treatment outcomes in TN.

Blink reflex monitoring in microvascular decompression for trigeminal neuralgia

Aim: To determine the value of the blink reflex in evaluating trigeminal sensory function during microvascular decompression for trigeminal neuralgia.Methods: The blink reflex (BR) in 103 patients with primary typical trigeminal neuralgia treated by microvascular decompression (MVD) was tested pre- and intraoperatively. The changes in BR were recorded. All patients underwent general anesthesia with intravenous propofol and fentanyl. Surgical efficacy and complications were evaluated after surgery. The relationship between intraoperative changes in the BR and postoperative trigeminal sensory function was analyzed.Results: The BR was elicited in all patients before surgery, and no significant difference was found between the affected side and the contralateral side. In 93 of the 103 cases, the BR was successfully elicited during MVD surgery. Therefore, the recordability of the BR was 90.29%. R1 latency on the affected side and the contralateral side were 11.62 ± 4.96 ms and 11.66 ± 4.37 ms, respectively. During MVD surgery, R1 of the BR disappeared on the affected side in 7 cases and remained in 86 cases. After the operation, 98 of the 103 patients had immediate and complete remission of trigeminal neuralgia symptoms, and 5 cases had partial remission. The 7 patients whose R1 disappeared during the surgery all experienced facial numbness postoperatively. Of the 86 patients whose R1 remained, only 2 patients had postoperative facial numbness. Of the 10 patients whose R1 was not recordable during the operation, one complained of postoperative facial numbness. No patients had complications such as facial paralysis, cerebrospinal fluid leakage, and death.Conclusions: Conclusion: The blink reflex may allow monitoring of trigeminal sensory function during microvascular decompression under general anesthesia.

Virtual reality-based evaluation of neurovascular conflict for the surgical planning of microvascular decompression in trigeminal neuralgia patients

OBJECTIVE

Trigeminal neuralgia (TN) is a lightning bolt of violent, electrifying, and stinging pain, often secondary to the neurovascular conflict (NVC). The vessels involved in NVC are mostly arteries and rarely veins. Evaluation of NVC in the deep infratentorial region is inseparably connected with cranial imaging. We retrospectively analyzed the potential influence of three-dimensional (3D) virtual reality (VR) reconstructions compared to conventional magnetic resonance imaging (MRI) scans on the evaluation of NVC for the surgical planning of microvascular decompression in patients with TN.

METHODS

Medical files were retrospectively analyzed regarding patient- and disease-related data. Preoperative MRI scans were retrospectively visualized via VR software to detect the characteristics of NVC. A questionnaire of experienced neurosurgeons evaluated the influence of VR visualization technique on identification of anatomical structures involved in NVC and on surgical strategy.

RESULTS

Twenty-four patients were included and 480 answer sheets were evaluated. Compared to conventional MRI, image presentation using 3D-VR modality significantly influenced the identification of the affected trigeminal nerve (p = 0.004), the vascular structure involved in the NVC (p = 0.0002), and the affected side of the trigeminal nerve (p = 0.005).

CONCLUSIONS

In patients with TN caused by NVC, the reconstruction of conventional preoperative MRI scans and the spatial and anatomical presentation in 3D-VR models offers the possibility of increased understanding of the anatomy and even more the underlying pathology, and thus influences operation planning and strategy.

Analgesic effect of gum chewing in patients with burning mouth syndrome

The cause of burning mouth syndrome (BMS) is unknown. Although no effective treatment has been established, BMS patients frequently chew gum to alleviate pain. To identify the cause and new treatments for BMS, this study investigated the psychophysical and pharmacological properties of gum chewing to better understand its pain-relieving effects. In this prospective, blinded study, plasma catecholamine and serotonin levels and Profile of Mood States (POMS) scores were assessed after gum chewing or simulated chewing in 40 women (20 BMS patients and 20 age-matched controls). Visual analogue scale (VAS) scores for pain decreased significantly in BMS patients after gum chewing and simulated chewing. Moreover, resting VAS scores of BMS patients were significantly positively correlated with plasma adrenaline level. Furthermore, gum chewing was significantly correlated with lower plasma adrenaline level, VAS score, and tension-anxiety score. These results suggest that adrenaline is important in the pathogenesis of BMS pain and that the analgesic effect of gum chewing is induced through the potential effects of anxiety reduction, although this effect might not be specific to BMS. In addition, the analgesic effect of gum chewing was not induced solely by chewing motion.

No Association of Polymorphisms in Nav1.7 or Nerve Growth Factor Receptor Genes with Trigeminal Neuralgia

OBJECTIVE

Trigeminal neuralgia is defined as a sudden severe shock-like pain within the distribution of the trigeminal nerve. Pain is a subjective experience that is influenced by gender, culture, environment, psychological traits, and genes. Sodium channels and nerve growth factor play important roles in the transmission of nociceptive signals and pain. The aim of this study was to investigate the occurrence of Nav1.7 sodium channel and nerve growth factor receptor TrkA gene polymorphisms (SCN9A/rs6746030 and NTRK1/rs633, respectively) in trigeminal neuralgia patients.

METHODS

Ninety-six subjects from pain specialty centers in the southeastern region of Brazil were divided into 2 groups: 48 with classical trigeminal neuralgia diagnosis and 48 controls. Pain was evaluated using the visual analog scale and multidimensional McGill Pain Questionnaire. Genomic DNA was obtained from oral swabs in all individuals and was analyzed by real-time polymerase chain reaction.

RESULTS

No association was observed between evaluated polymorphisms and trigeminal neuralgia. For allele analyses, patients and controls had similar frequencies for both genes. Genotype distribution or allele frequencies of polymorphisms analyzed here did not correlate to pain scores.

CONCLUSIONS

Although no association of evaluated polymorphisms and trigeminal neuralgia diagnosis or pain severity was observed, our data do not exclude the possibility that other genotypes affecting the expression of Nav1.7 or TrkA are associated with the disease. Further studies should investigate distinct genetic polymorphisms and epigenetic factors that may be important in expression of these molecules.

Design of Phase 3 Studies Evaluating Vixotrigine for Treatment of Trigeminal Neuralgia

Purpose

Vixotrigine (BIIB074) is a voltage- and use-dependent sodium channel blocker. These studies will evaluate the efficacy and safety of vixotrigine in treating pain experienced by patients with trigeminal neuralgia (TN) using enriched enrollment randomized withdrawal trial designs.

Patients and Methods

Two double-blind randomized withdrawal studies are planned to evaluate the efficacy and safety of vixotrigine compared with placebo in participants with TN (NCT03070132 and NCT03637387). Participant criteria include ≥18 years old who have classical, purely paroxysmal TN diagnosed ≥3 months prior to study entry, who experience ≥3 paroxysms of pain/day. The two studies will include a screening period, 7-day run-in period, a 4- or 6-week single-dose-blind dose-optimization period (Study 1) or 4-week open-label period (Study 2), and 14-week double-blind period. Participants will receive vixotrigine 150 mg orally three times daily in the dose-optimization and open-label periods. The primary endpoint of both studies is the proportion of participants classified as responders at Week 12 of the double-blind period. Secondary endpoints include safety measures, quality of life, and evaluation of vixotrigine population pharmacokinetics.

Conclusion

There is a need for an effective, well-tolerated, noninvasive treatment for the neuropathic pain associated with TN. The proposed studies will evaluate the efficacy and safety of vixotrigine in treating pain experienced by patients with TN.

Complication Rates During Endoscopic Microvascular Decompression Surgery Are Low With or Without Petrosal Vein Sacrifice

OBJECTIVE

Endoscopic-microvascular decompression (E-MVD) is a well-described treatment for trigeminal neuralgia (TGN), but there has been debate on the safety of intraoperative sacrifice of the petrosal vein (PV) due to concern for subsequent venous insufficiency. Our objective was to investigate the risk of PV sacrifice during E-MVD in TGN and subsequent postoperative complications and pain outcomes.

METHODS

5 five-year review yielded 201 patients who underwent MVD for TGN. PV sacrifice, vascular compressive anatomy, and postoperative complications attributable to venous insufficiency were analyzed. Preoperative and postoperative pain outcomes were analyzed.

RESULTS

PV was sacrificed in 118 of 201 (59%) of patients, with 43 of 201 (21%) patients undergoing partial sacrifice versus 75 of 201 (37%) with complete sacrifice. No cases of venous infarction, cerebellar swelling, or fatal complications were noted in either cohort. Non-neurologic complications occurred in 1.69% (2 of 118) of patients with PV sacrifice and 0% (0 of 83) of patients with PV preservation. Neurologic deficits (facial palsy, conductive hearing loss, gait instability, memory deficit) occurred in equal proportions in PV preservation and sacrifice groups (2.41% vs. 1.69%) Overall, 87.3% (145 of 166) patients reported their pain as "very much improved" or "much improved" at 1 month, and no difference between groups was identified.

CONCLUSIONS

This study did not find higher complication rates in patients undergoing petrosal vein sacrifice during E-MVD for trigeminal neuralgia. In this series where petrosal vein was sacrificed only 59% of the time, it appears to be a safe technique, but larger studies will be needed to determine true incidence of complications after PV sacrifice.

Both ipsilateral and contralateral localized vibratory stimulations modulated pain-related sensory thresholds on the foot in mice and humans

Purpose

This study was aimed to investigate the effect of localized vibration on sensory thresholds in mice and humans using a novel quantitative method.

Participants and methods

The sensory thresholds of 7-week-old male C57BL/6J mice were measured with four sine-wave electrostimulation frequencies (5, 50, 250, and 2,000 Hz) before and after applying 2-minute vibration to the plantar side of the foot in mice. In human participants (16 males and 16 females; mean age, 21.0±0.8 years), the sensory threshold was measured at 50 Hz before and after applying 2-minute and 5-minute vibrations to the dorsal side of the foot.

Results

Application of a 2-minute vibration at either the ipsilateral or contralateral side modulated the sensory thresholds elicited by a 5- or 50-Hz right electrostimulation in mice. In human participants, application of a 5-minute vibration at either the ipsilateral or contralateral side modulated the sensory threshold elicited by 50-Hz right electrostimulation, but had no effect on local skin temperature. These results suggest that the right side of pain-related Aδ fibers (50 Hz) or C fibers (5 Hz) was modulated by the localized ipsilateral or contralateral side of vibratory stimuli, respectively, in mice and humans.

Conclusion

The ability of contralateral vibration to modify the right sensory thresholds suggests possible involvement of the central nervous system in vibratory modulation.

Measuring the impact of trigeminal neuralgia pain: the Penn Facial Pain Scale-Revised

BACKGROUND AND OBJECTIVE

The Penn Facial Pain Scale (Penn-FPS) was originally developed as a supplemental module to the Brief Pain Inventory Pain Interference Index (BPI-PII) in order to fully assess the impact of trigeminal neuralgia (TN) pain on patients' health-related quality of life (HRQoL). The current objective is to create and establish the content validity of a new stand-alone version of the measure, the Penn-FPS-Revised (Penn-FPS-R).

METHODS

Twenty participants (15 USA and 5 UK) with confirmed TN engaged in concept elicitation and cognitive debriefing interviews. These semi-structured interviews allowed participants to spontaneously describe the ways in which TN impacts on HRQoL and report on the extent to which the Penn-FPS and BPI-PII measure concepts are most relevant to them. Participants were also asked to report on the suitability of the instructions, recall period, and response options.

RESULTS

Concept elicitation revealed nine themes involving TN restrictions on daily activities and HRQoL, including: "talking," "self-care," "eating," "eating hard foods/chewing foods," "daily activities," "activities with temperature change," "touching," "mood," and "relationships." Cognitive debriefing confirmed that all of the Penn-FPS concepts and some of the BPI-PII concepts ("mood," "general activities," and "relations with others") were relevant, although some items required edits to better capture individuals' experiences. The impact of temperature and/or weather on activities was also identified as an important concept that is not captured by the Penn-FPS or BPI-PII. Participants confirmed the acceptability of recall period, instructions, and response options. Results from the interviews were applied to create the Penn-FPS-R, a new brief outcome measure that assesses the impacts of TN most important to patients.

CONCLUSION

The Penn-FPS-R is a new 12-item HRQoL outcome measure with content validity that can be used to assess and monitor the impact of TN treatment interventions in both clinical practice and research.

Evaluation of CyberKnife Radiosurgery for Recurrent Trigeminal Neuralgia

Stereotactic radiosurgery (SRS) has evolved as an accepted treatment for medication resistant trigeminal neuralgia. Initial results are very good but follow-up over three to five years shows a gradual return of pain in up to 50% of treated patients, often requiring further treatment. The results with repeat SRS using the isocentric Gamma Knife (GK) (Elekta, Stockholm, Sweden), especially in patients having initially good results, are very similar to the outcomes after the initial treatment although there is an increased risk of residual facial numbness secondary to the additional radiation dose to the trigeminal nerve. However, after 2000, non-isocentric SRS systems began to be used for treating trigeminal neuralgia including the CyberKnife (CK) (Accuray, Sunnyvale, California) as well as various linear accelerator (LINAC) based systems. This report specifically examines a series of recurrent trigeminal cases treated by the same group of physicians with the CK system. Similar doses and locations on the trigeminal nerve and/or the root entry zone were used for both initial and repeat SRS treatment regardless of system used. Although there are numerous series reporting the use of GK for recurrent treatment for recurrent trigeminal neuralgia, there are no series reviewing the results and long-term effectiveness using CK for repeat SRS for recurrent trigeminal pain. We reviewed 23 cases that had initial treatment for trigeminal neuralgia either surgically or with SRS with either the GK or CK and then a later second procedure only with CK. The follow-up after the second CK SRS ranged from three to 13 years found that the results are very similar to the multiple reports in the literature describing second or third SRS treatments with the GK. Results of repeat radiosurgery treatment of recurrent trigeminal neuralgia appear to be independent of the system used and are primarily based on proper target and dose to the trigeminal nerve.

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.

New tubeless video-assisted thoracoscopic surgery for small pulmonary nodules

Objectives

Problems associated with intubation, chest drainage and urinary catheterization can have a negative impact on patient's recovery after thoracic surgery. We therefore evaluated the feasibility of a new tubeless (spontaneous ventilation without tracheal intubation, urinary catheterization, and no post-operative chest drain placement) approach to perform video-assisted thoracoscopic surgery (VATS) for small pulmonary nodules (SPN) less than 2cm in diameter.

Methods

From 1 January 2012 to 31 December 2014, 34 patients with SPNs were treated using tubeless VATS in our centre. To be eligible for this approach, the patient must have a body mass index (BMI) of less than 25; ASA grade of II or less; no history of prostate or renal disease and no parenchymal air leak at the end of surgery. All operations were performed via an anterior uniportal VATS under spontaneous ventilation without tracheal intubation.

Results

All patients [29 male:5 females; average age: 58 ± 19 years old] completed their operation under spontaneous ventilation, without conversion to endotracheal intubation. There was good operative exposure and definite diagnosis was obtained in all patients. The anaesthesia and operating time were 23 ± 3 min and 43 ± 10 min, respectively. No major intra-operative or post-operative complications were seen. Patients recovered from their anaesthesia (fully awake) within a mean time of 18 ± 3 min after surgery, and were eating 42 normally on an average of 5 ± 1 h post-operatively. No patients had pain on deep breathing or coughing (Bruggemann Comfort Score < 2). Within 24 h after surgery, 26 patients were discharged, while the remaining 8 patients were discharged on the second day. None of the patients needed re-invention with chest drainage or urinary catheterization even after discharge. All patients remained well at a median [interquartile range] follow-up time of 3[2-5] weeks.

Conclusions

Tubeless VATS approach for SPNs is feasible in carefully selected patients. Intubation, chest drainage, and/or urinary catheterization may not be necessary in all patients.