Neurosurgical Treatment of Trigeminal Neuralgia

Effect of Non-Ablative Non-Thermal CO2 Laser on Drug-Resistant Trigeminal Neuralgia: A Pilot Study

Background: Trigeminal neuralgia is one of the most severe pain conditions that humans experience. Drug resistance is a challenging event during treatment that results in using higher doses of drugs or referring for neurosurgical treatment. Laser therapy is also an effective method for pain control. Objective: The aim of this study was to evaluate the effect of non-ablative non-thermal CO₂ laser (NANTCL) on reducing pain in patients with drug-resistant trigeminal neuralgia (DRTN) for the very first time. Materials and methods: Twenty-four patients with DRTN were randomly divided into laser and placebo groups. Patients in the laser group received NANTCL (10,600 nm, 1.1 W, 100 HZ, 20 sec) on trigger points that were covered with lubricant gel 3 days in a week for 2 weeks. The placebo group received sham laser. The patients were requested to grade their pain on a visual analog scale (VAS) immediately, 1 week, 1 month, and 3 months after treatment. Results: In the laser group, the results revealed a significant decrease between the initial pain and the pain in all follow-up sessions. Only in three patients, 3 months after completion of laser therapy, pain returned to the initial level. In the control group, a significant difference was seen only between the pain of baseline and final session of laser irradiation. In laser group, the mean of pain (VAS) was lower than the placebo group in all follow-up sessions; however, it was only significant for 1 week after laser therapy. Conclusions: This study revealed that short-period application of NANTCL is effective for pain relief in patients with DRTN, especially those with extraoral trigger points. Clinical trial registration number: IRCT2013052113406N1.

Percutaneous radiofrequency trigeminal rhizotomy benefits in patients with refractory trigeminal neuralgia

A significant number of patients suffers from refractory trigeminal neuralgia (TN) after receiving microvascular decompression (MVD) or other neuro-destructive procedure such as gamma knife radiosurgery (GKRS). This study aims to demonstrate a remediable, reproducible approach to treating refractory pain effectively by percutaneous radiofrequency trigeminal rhizotomy (RF-TR).A total of 392 patients with TN were treated by RF-TR during the past 10 years. Among these patients, 48 cases who had received either MVD, GKRS alone, or a combination of both were assigned to group A. Those who had not received any form of treatment (125 patients) or failed to respond medically (130 patients) were assigned as the control group (group B). All the RF-TR were performed by a single surgeon with the aid of intraoperative computed tomography (iCT)-based neuronavigation with magnetic resonance (MR) image fusion. The outcome measure was the numerical rating scale (NRS) expressed subjectively by patients. The paired Student t test and the analysis of covariance (ANCOVA) were used for statistical analysis.In group A, 21 of 24 patients (88%) had significant improvement (NRS change ≥5) in facial pain after RF-TR. The average NRS score was 9.75 ± 0.53 before the procedure and 1.92 ± 3.35 post-treatment (significant NRS decrease [P = .000]). On the other hand, in group B, 226 of 255 patients (89%) also had dramatic amelioration of facial pain after RF-TR. The average NRS score was 9.46 ± 0.69 before the procedure and 1.62 ± 2.85 post-treatment (7.84 ± 2.82 in NRS decrease [P = .008]). By using a univariate ANCOVA, no statistical significance was found in NRS score improvement between the two groups.Repeated MVD and GKRS for refractory TN may be less desirable due to a greater risk of mortality (up to 0.8%) and morbidity (4% of serious complications). Conversely, RF-TR administration with the novel navigation technique by using iCT and MR image fusion is free from any remarkable and irreversible morbidities. In this study, RF-TR not only provided an alternative and effective strategy if TN recurred but also resulted in the same NRS score improvement regardless of the status of prior treatment.

Application of Augmented Reality in Percutaneous Procedures-Rhizotomy of the Gasserian Ganglion

BACKGROUND

Percutaneous rhizotomy of the Gasserian ganglion for trigeminal neuralgia is an effective therapeutic procedure. Yet, landmark-guided cannulation of the foramen ovale is manually challenging and difficult to learn.

OBJECTIVE

To overcome these limitations, we assessed the feasibility and accuracy of an augmented reality (AR)-guided puncture of the foramen ovale.

METHODS

A head phantom with soft tissue structures of the facial area was built. A three-dimensional (3D)-dataset of the phantom was generated using a stereotactic planning workstation. An optimal trajectory to the foramen ovale was created and then transferred to an AR headset. A total of 2 neurosurgeons and 2 neuroradiologists independently performed 8 AR-guided and 8 landmark-guided cannulations of the foramen ovale, respectively. For each AR-guided cannulation, the hologram was manually aligned with the phantom. Accuracy of the cannulation was evaluated using the Euclidean distance to the target point as well as the lateral deviation of the achieved trajectory from the planned trajectory at target point level.

RESULTS

With the help of AR guidance, a successful cannulation of the foramen ovale was achieved in 90.6% compared to the purely landmark-based method with 18.8%. Euclidean distance and lateral deviation were significantly lower with AR guidance than landmark guidance (P < .01).

CONCLUSION

AR greatly improved accuracy of simulated percutaneous rhizotomy of the Gasserian ganglion.

Prevalence of Chronic Orofacial Pain in Elderly Patients Referred to Shiraz Dental School From 2005 to 2017

Background

Orofacial pain is presented mainly as a pain in the front part of the head, including the oral cavity. Adult and elderly patients are important target groups affected by this chronic pain, which may cause several problems.

Methods

In this cross-sectional study, the characteristics of patients who suffered from orofacial pain were evaluated. The data such as patients' gender, age, pain diagnoses, treatments, responses to treatments, duration and severity of pain, and disability were collected from their records. The diagnoses were provided based on the characteristics of pain, X-ray findings, physiological findings, lab tests, nerve block injection, and a drug challenge test.

Results

Among all the 5,221 patients referred to Oral and Maxillofacial Medicine and Prosthodontics Department, 583 (11.16%) reported orofacial pain as the chief complaint. The frequency of orofacial pain was more prevalent among women than men. Burning mouth syndrome was the most prevalent cause of orofacial pain in the elderly, followed by temporomandibular disorder and trigeminal neuralgia.

Conclusions

Most cases of orofacial pain in elderly patients were burning mouth syndrome, temporomandibular disorder, and neuralgia. It was more observed in females than males with the mean age of 55.3 ± 10.7 years old.

Management of Arteriovenous Malformations Associated with Developmental Venous Anomalies: A Literature Review and Report of 2 Cases

BACKGROUND

Classification of cerebrovascular malformations has revealed intermediary lesions that warrant further review owing to their unusual presentation and management. We present 2 cases of arteriovenous malformation (AVM) associated with a developmental venous anomaly (DVA), and discuss the efficacy of previously published management strategies.

METHODS

Two cases of AVMs associated with DVA were identified, and a literature search for published cases between 1980 and 2016 was conducted. Patient demographic data and clinical features were documented.

RESULTS

In case 1, a 29-year-old female presenting with parenchymal hemorrhage and left homonymous hemianopia was found to have a right parieto-occipital AVM fed from the anterior cerebral, middle cerebral, and posterior cerebral arteries, with major venous drainage to the superior sagittal sinus. In case 2, imaging in a 34-year-old female evaluated for night tremors and incontinence revealed a left parietal AVM with venous drainage to the superior sagittal sinus. Including our 2 cases, 22 cases of coexisting AVMs and DVAs have been reported in the literature. At presentation, 68% had radiographic evidence of hemorrhage. Stereotactic radiosurgery was performed in 7 cases, embolization in 6 cases, surgical resection in 4 cases, and multimodal therapy in 5 cases. Radiography at follow-up demonstrated successful AVM obliteration in 67% of cases (12 of 18).

CONCLUSIONS

Patients with coexisting AVMs and DVAs tend to have a hemorrhagic presentation. Contrary to traditional AVM management, in these cases it is important to preserve the draining vein via the DVA to ensure a safe, sustained circulatory outflow of the associated brain parenchyma while achieving safe AVM obliteration.

Efficacy of primary microvascular decompression versus subsequent microvascular decompression for trigeminal neuralgia

OBJECTIVE Trigeminal neuralgia (TN) is characterized by intermittent, paroxysmal, and lancinating pain along the distribution of the trigeminal nerve. Microvascular decompression (MVD) directly addresses compression of the trigeminal nerve. The purpose of this study was to determine whether patients undergoing MVD as their first surgical intervention experience greater pain control than patients who undergo subsequent MVD. METHODS A retrospective review of patient records from 1998 to 2015 identified a total of 942 patients with TN and 500 patients who underwent MVD. After excluding several cases, 306 patients underwent MVD as their first surgical intervention and 175 patients underwent subsequent MVD. Demographics and clinicopathological data and outcomes were obtained for analysis. RESULTS In patients who underwent subsequent MVD, surgical intervention was performed at an older age (55.22 vs 49.98 years old, p < 0.0001) and the duration of symptoms was greater (7.22 vs 4.45 years, p < 0.0001) than for patients in whom MVD was their first surgical intervention. Patients who underwent initial MVD had improved pain relief and no improvement in pain rates compared with those who had subsequent MVD (95.8% and 4.2% vs 90.3% and 9.7%, respectively, p = 0.0041). Patients who underwent initial MVD had significantly lower rates of facial numbness in the pre- and postoperative periods compared with patients who underwent subsequent MVD (p < 0.0001). The number of complications in both groups was similar (p = 0.4572). CONCLUSIONS The results demonstrate that patients who underwent other procedures prior to MVD had less pain relief and a higher incidence of facial numbness despite rates of complications similar to patients who underwent MVD as their first surgical intervention.

Usefulness of a Virtual Reality Percutaneous Trigeminal Rhizotomy Simulator in Neurosurgical Training

BACKGROUND

Simulation-based training may be incorporated into neurosurgery in the future.

OBJECTIVE

To assess the usefulness of a novel haptics-based virtual reality percutaneous trigeminal rhizotomy simulator.

METHODS

A real-time augmented reality simulator for percutaneous trigeminal rhizotomy was developed using the ImmersiveTouch platform. Ninety-two neurosurgery residents tested the simulator at American Association of Neurological Surgeons Top Gun 2014. Postgraduate year (PGY), number of fluoroscopy shots, the distance from the ideal entry point, and the distance from the ideal target were recorded by the system during each simulation session. Final performance score was calculated considering the number of fluoroscopy shots and distances from entry and target points (a lower score is better). The impact of PGY level on residents' performance was analyzed.

RESULTS

Seventy-one residents provided their PGY-level and simulator performance data; 38% were senior residents and 62% were junior residents. The mean distance from the entry point (9.4 mm vs 12.6 mm, P = .01), the distance from the target (12.0 mm vs 15.2 mm, P = .16), and final score (31.1 vs 37.7, P = .02) were lower in senior than in junior residents. The mean number of fluoroscopy shots (9.8 vs 10.0, P = .88) was similar in these 2 groups. Linear regression analysis showed that increasing PGY level is significantly associated with a decreased distance from the ideal entry point (P = .001), a shorter distance from target (P = .05), a better final score (P = .007), but not number of fluoroscopy shots (P = .52).

CONCLUSION

Because technical performance of percutaneous rhizotomy increases with training, we proposed that the skills in performing the procedure in our virtual reality model would also increase with PGY level, if our simulator models the actual procedure. Our results confirm this hypothesis and demonstrate construct validity.

Sodium hydrosulfide relieves neuropathic pain in chronic constriction injured rats

Aberrant neuronal activity in injured peripheral nerves is believed to be an important factor in the development of neuropathic pain (NPP). Channel protein pCREB of that activity has been shown to mitigate the onset of associated molecular events in the nervous system, and sodium hydrosulfide (NaHS) could inhibit the expression of pCREB. However, whether NaHS could relieve the pain, it needs further experimental research. Furthermore, the clinical potential that NaHS was used to relieve pain was limited so it would be required. To address these issues, the rats of sciatic nerve chronic constriction injury (CCI) were given intraperitoneal injection of NaHS containing hydrogen sulfide (H₂S). The experimental results showed that NaHS inhibited the reduction of paw withdrawal thermal latency (PWTL), mechanical withdrawal threshold (MWT), and the level of pCREB in CCI rats in a dose-dependent manner and they were greatly decreased in NaHS_M group (P < 0.05). NaHS alleviates chronic neuropathic pain by inhibiting expression of pCREB in the spinal cord of Sprague-Dawley rats.

The serotonin transporter gene polymorphism is associated with the susceptibility and the pain severity in idiopathic trigeminal neuralgia patients

BACKGROUND

To investigate the possible association between the serotonin transporter gene (5-HTTLPR) and rs 25531 polymorphism and the susceptibility and the pain severity in Trigeminal Neuralgia patients.

METHODS

A total of 244 TN patients and 280 age and sex matched healthy volunteer were recruited. 5-HTTLPR and rs 25531 genotyping were performed. All patients received the carbamazepine treatment and the treatment response was evaluated at 6 months.

RESULTS

The genotype distribution of 5-HTTLPR between TN patients and controls were significantly different. The TN Patients had a higher prevalence of short-short genotype than controls. The short-short genotype carriers are also significantly associated with higher pain severity and poorer carbamazepine treatment response compared to the long-long genotype carriers. In contrast, the rs 25531 polymorphism was not associated with the susceptibility to TN, neither with the pain severity and the treat response to carbamazepine.

CONCLUSION

The 5-HTTLPR polymorphism is associated with the susceptibility to TN and pain severity of TN.

Cranial neuralgias

This article describes the clinical findings of cranial neuralgias, such as trigeminal neuralgia, glossopharyngeal neuralgia, nervus intermedius neuralgia, and others, and postherpetic neuralgia. Pathophysiology of these neuralgias, diagnostic methods, and treatment are also discussed. This information will enable the dentist to diagnose patients who have these rare conditions.