Riveting technique in percutaneous balloon compression for trigeminal neuralgia remedy

BACKGROUND

The percutaneous balloon compression (PBC) is a safe and simple treatment for trigeminal neuralgia. It works by compressing the Gasserian ganglion to block pain signals from the trigeminal nerve. To ensure effectiveness, it is important to focus the compression on the lower part of the balloon.

OBJECTIVE

To validate the efficacy of a riveting technique, specifically pulling an inflated balloon, in order to apply enhanced compression on the ganglion.

METHODS

To compare this novel technique with the conventional approach, a retrospective investigation was conducted on consecutive PBCs performed in our department between 2019 and 2022. For postoperative outcome assessment, efficacy was defined as achieving a VAS score of 0 or an improvement exceeding 5 points. Postoperative numbness was graded as none, mild, or severe based on its impact on daily life and tolerance level.

RESULTS

Excluding cases with missed follow-up, a total of 179 participants were included in the study, and their follow-up period ranged up to 40 months. Postoperatively, symptomatic remission was achieved by 98.1% (52/53) of patients in the riveting technique group compared to 87.3% (110/126) in the conventional group (P<0.05). At the last follow-up period, with recurrence observed over time, the long-term efficacy of riveting and conventional groups were 94.3% and 74.6%, respectively (P<0.05). The majority of cases in both groups experienced ipsilateral facial numbness immediately following PBC, which appeared to diminish after 3 months in both groups without significant difference between them (P>0.05).

Reactivation of varicella zoster virus following trigeminal schwannoma resection

Varicella zoster is found exclusively in humans. Infected people with this virus result in chickenpox followed by dormant virus within neural ganglia. This dormant virus, once activated, may affect any ganglia or nerves of the body but most commonly involves the thoracic, cervical and trigeminal nerves in decreasing order of frequency. We review three such cases in which manipulation of the trigeminal ganglion resulted in reactivation of varicella at homologous operative sites. Each patient underwent surgeries in which the trigeminal ganglion was manipulated for the resection of trigeminal schwannoma under a microscope through various approaches. All three patients developed reactivation of varicella at homologous operative sites. A thorough history of chickenpox infection should be taken in patients who are undergoing surgeries for trigeminal pathology. Early diagnosis should be made once any vesicular lesions are seen with prompt treatment. Reassurance and counselling are necessary in these patients. If possible, prophylaxis may be started in all such patients. Further studies are warranted to determine the exact cause of reactivation.

Anatomical measurements of trigeminal ganglion: a cadaver study

It is difficult to obtain specific information regarding the trigeminal ganglion (TG), especially pediatric TG. The aim of present study was to determine the parameters of the TG and assist in the neuroablative treatment of trigeminal neuralgia (TN). Thirty-seven sides of cadaver heads that had undergone gross anatomical examination were included, with 29 sides of adults and 8 sides of infants. The distance and angles were measured among 12 points, with nine points adjacent to the TG and three points on the foramen ovale (FO). The three points on FO were represented as three different surgical approaches for TN: posterior FO approach (PFO), lateral FO approach (LFO), and anterior FO approach (AFO). A high similarity was found in pediatric TG. No statistical difference was detected in either the distance or the angles between the 12 points. Statistical difference was found in adult heads in some of the distances, which included PFO to point 5 (17.97 ± 3.35 mm in the left and 15.52 ± 2.28 mm in the right; p = 0.03) and LFO to point 5 and point 8. Moreover, the angle for PFO to point 5 showed a statistically significant difference (60.10 ± 14.02 in the left and 46.63 ± 10.48 in the right; p = 0.01). These findings revealed that surgical neuroablation for patients with TN should be performed more carefully when the PFO or LFO approach is adopted, with a precise preoperative evaluation to avoid corneal complications. Two safety radiofrequency rhizotomy points are also presented to deal with two different kinds of TN.

Clinical study of puncture technique in single division of the trigeminal ganglion intumescentia

OBJECTIVE

We explored the feasibility of single-division puncture in the ophthalmic division, maxillary division, and mandibular division of the trigeminal ganglion intumescentia (TGI) and the feasibility of radiofrequency treatment of trigeminal neuralgia.

METHODS

According to the previous anatomical image studies, 3D Slicer software was used to analyze the CT images of the patients. The trigeminal ganglion fossa (TGF) was used as the imaging sign. TGI was identified in the sagittal plane along the fiber. The puncture path starts from the TGI center-foramen ovale line, extending outward to the epidermis as the needle insertion point, and extending inward to the division boundary. For lateral puncture, which is blocked by the mandible, the positions of closed mouth, open mouth, and over-open mouth were used. Multiple targets were generated using straight electrodes and curved electrodes to achieve full coverage of TGI. According to the preoperative design, general anesthesia surgery was performed. Xper CT was used for imaging, and the puncture was guided by Xper Guide. Radiofrequency treatment of TGI was conducted.

RESULTS

In total, 45 patients with trigeminal neuralgia underwent 50 single-division TGI punctures. The procedure was smooth and the compliance with the design was good. Continuous radiofrequency (CRF) was performed, the VAS scores were 25 times at 70°C, 19 times at 65°C, two times at 60°C, and two times at 50°C (both in the ophthalmic division). Pulsed radiofrequency (PRF) was conducted two times. Within 24 h after the procedure, the VAS scores were all 0. From 1 to 7 days after the procedure, pain recurrence was found in three cases, of whom two cases received pulsed radiofrequency treatment. Patients were followed up for 1-24 months and there were no recurrence. After continuous radiofrequency at 65-70°C, the moderate tactile loss was observed, and nearly half of the patients had food residues on the surgical side after 6 months. After continuous radiofrequency at 60°C, there was mild tactile loss and no food residue. The tactile sensation was slightly decreased after continuous radiofrequency at 50°C, and the tactile sensation was normal the next day.

CONCLUSION

Trigeminal ganglion intumescentia single-division radiofrequency is effective and feasible for the treatment of trigeminal neuralgia.

Variants of the Anterior Subtemporal Approach to the Gasserian Ganglion and Related Structures: An Anatomical Study With Relevant Implications for Keyhole Surgery

BACKGROUND

The advantages and limitations of different craniotomy positions and approach trajectories to the gasserian ganglion (GG) and related structures using an anterior subtemporal approach have not been studied systematically. Knowledge of these features is of importance when planning keyhole anterior subtemporal (kAST) approaches to the GG to optimize access and minimize risks.

METHODS

Eight formalin-fixed heads were used bilaterally to assess temporal lobe retraction (TLR), trigeminal exposure, and relevant anatomical aspects of extra- and transdural classic anterior subtemporal (CLAST) approaches compared with slightly dorsally and ventrally allocated corridors.

RESULTS

TLR to the GG and foramen ovale was found to be lower via the CLAST approach (P < 0.001). Using the ventral variant, TLR to access the foramen rotundum was minimized (P < 0.001). The overall TLR was maximal using the dorsal variant (P < 0.001) owing to interposition of the arcuate eminence. An extradural CLAST approach required wide exposure of the greater petrosal nerve (GPN) and middle meningeal artery (MMA) sacrifice. Both maneuvers were spared using a transdural approach. Using CLAST, medial dissection >39 mm can enter the Parkinson triangle, jeopardizing the intracavernous internal carotid artery. The ventral variant enabled access to the anterior portion of the GG and foramen ovale without the need for MMA sacrifice or GPN dissection.

CONCLUSIONS

The CLAST approach provides high versatility to approach the trigeminal plexus, minimizing TLR. However, an extradural approach jeopardizes the GPN and requires MMA sacrifice. The risk of cavernous sinus violation exists when progressing medially beyond 4 cm. The ventral variant has some advantages to access the ventral structures and avoid MMA and GPN manipulation. In contrast, the usefulness of the dorsal variant is rather limited owing to the greater TLR required.

Radiofrequency thermoablation of the peripheral branches of trigeminal nerve versus the Gasserian ganglion for treating idiopathic trigeminal neuralgia: A systematic review and meta-analysis

BACKGROUND

Trigeminal neuralgia is characterized by pain at the distribution of one or more of the trigeminal nerve branches and is usually treated with anti-epileptic medication. When first line treatment fails, patients receive other treatment modalities including radiofrequency thermoablation (RFT) of the Gasserian ganglion and peripheral branches of the trigeminal nerve. The aim of this study is to compare RFT of the Gasserian ganglion and peripheral branches of trigeminal nerve in terms of efficacy and rate of complications.

METHODS

This was a systematic review and meta-analysis that searched Medline, Cochrane Central Register of Controlled Trials, and Embase using Medical Subject Headings and the references of the enrolled studies with no restriction on date. We included only RCTs that compared the RFT of the Gasserian ganglion and peripheral branches of trigeminal nerve with one of the following outcomes: pain scales, immediate effective rate, recurrence rate, and complications.

RESULTS

Five articles were eligible for our review and showed that there was no difference between RFT of the peripheral nerves and the Gasserian ganglion in terms of pain scores. There was a non-significant trend for RFT of the peripheral nerve to have higher immediate effect rates and higher recurrence rates. RFT of the Gasserian ganglion group was associated with masticatory weakness, while the other group was associated with facial swelling and numbness of V2.

CONCLUSION

RFT of the peripheral branches is a safe and effective method to treat idiopathic trigeminal neuralgia but leads to a higher recurrence rate when compared with RFT of the Gasserian ganglion.

Morphology of the trigeminal ganglion: anatomical structures related to trigeminal radiofrequency rhizotomy

BACKGROUND

Trigeminal neuralgia is the most common example of craniofacial neuralgia. Its etiology is unknown and is characterized by severe episodes of paroxysmal pain. The trigeminal ganglion and its adjacent anatomical structures have a complex anatomy. The foramen ovale is of great importance during surgical procedures such as percutaneous trigeminal rhizotomy for trigeminal neuralgia.

OBJECTIVE

We aimed to identify the anatomical structures associated with the trigeminal ganglion and radiofrequency rhizotomy on cadavers and investigate their relationship with the electrodes used during rhizotomy to determine the contribution of the electrode diameter and length to the effectiveness of the lesion formation on the ganglion.

METHODS

Five fresh-frozen cadaver heads injected with red silicone/latex were used. A percutaneous puncture was made by inserting of a cannula through the foramen ovale to create a pathway for electrodes. The relationships between the electrodes, Meckel's cave, trigeminal ganglion, and neurovascular structures were observed and morphometric measurements were obtained using a digital caliper.

RESULTS

Trigeminal ganglion, therefore the electrode in its final position, shows proximity with important anatomical structures. The electrode was inserted posteriorly into the foramen ovale in all of the specimens and was located on the retrogasserian fibers. This study revealed that the electrodes targeting the ganglion and passing through the foramen ovale may cause a radiofrequency lesion due to the contact effect of the dura itself pressing on the electrode. Pushing the cannula beyond the petroclival angle may result in puncturing of the dura propria and moving further away from the target area.

CONCLUSION

The success of radiofrequency rhizotomy is directly related to the area affected by the lesion. Understanding the mechanism of action underlying this procedure will ensure the effectiveness, success, and sustainability of the treatment.

Extracranial Non-Gasserian Ganglion Application of Radiofrequency Thermocoagulation on the Mandibular Branch of the Trigeminal through the Foramen Ovale for Trigeminal Neuralgia

BACKGROUND

Percutaneous radiofrequency ablation (RFA) of the trigeminal Gasserian ganglion via the foramen ovale is still one of the classic treatments for primary trigeminal neuralgia. However, the Gasserian ganglion is deep in the middle cranial fossa. Although it is a structure outside the brain tissue, the puncture needle must enter the encephalic to reach the Gasserian ganglion and so it is difficult to completely avoid the risk of intracranial hemorrhage and infection caused by puncture damage to intracranial blood vessels. It is not clear whether if it is possible for RFA at the extracranial non-gasserian-ganglion site via the exit of the cranial channel (foramen ovale) for patients with V3 trigeminal neuralgia (TN).

STUDY DESIGN

Prospective, clinical research study.

SETTING

Department of Anesthesiology and Pain Medical Center, Jiaxing, China.

METHODS

One hundred and seven patients with isolated mandibular branch trigeminal neuralgia were included. Radiofrequency thermocoagulation was performed by CT-guided percutaneous puncture through the foramen ovale. The puncture target was the midpoint of the horizontal transverse diameter of the oval foramen. If the tingling sensation in the mandibular nerve innervation area could be detected, the radiofrequency thermocoagulation (90°C, 120 sec) under intravenous anesthesia would be performed. We investigated the inclination angle, puncture angle and depth, puncture operation time, intraoperative complications and short-term and long-term results after operation.

RESULTS

After radiofrequency thermocoagulation, the pain in the mandibular branch dominant area was completely diminished in 104 patients. Two patients were cured after the second radiofrequency treatment. No intracranial hemorrhage not infection complications occurred, except for facial hematoma during operation in 21 cases. After 12-24 months of follow-up, 9 patients had recurrence and were still effective after receiving additional extracranial radiofrequency treatment.

LIMITATIONS

A control group should be established and more clinical data should be collected in future work.

CONCLUSION

Extracranial non-Gasserian-ganglion RF can achieve satisfactory results and improve the safety of radiofrequency treatment for trigeminal neuralgia.

A Cadaver Study Confirming the Location of Dye after Trigeminal Ganglion Rhizotomy

BACKGROUND

Radiofrequency thermal rhizotomy demonstrates an excellent treatment outcome with a high success rate among patients of intractable trigeminal neuralgia. The triangular plexus which is an immediate retrogasserian portion of the trigeminal root is suggested as the best place of lesioning during radiofrequency thermal rhizotomy. However, the anatomy of the triangular plexus has been relatively unrecognized, while the anatomical study related to therapeutic procedure is scarce.

OBJECTIVE

The purpose of this study is to confirm with gross and microscopic finding of the trigeminal system whether, if an electrode tip is placed on the petroclival junction in lateral cranial view, it actually arrives at the triangular plexus or not. In relation to therapeutic procedure, we examined the triangular plexus with morphological and histological methods.

STUDY DESIGN

Human cadaveric study.

SETTING

An anatomical laboratory in South Korea.

METHODS

Percutaneous procedure of radiofrequency thermal rhizotomy under C-arm guidance was performed in 8 cadavers. Final target of the electrode tip was the petroclival junction under true lateral cranial view. The location of the electrode tip was determined under observation of the presence of an injected dye. Triangular plexus size was measured grossly and microscopically. Gross and microscopic evaluation of the triangular plexus was performed.

RESULTS

Among 15 trigeminal systems, 8 showed dye appearance in the triangular plexus, while 6 showed it in the trigeminal ganglion. Overall, 53% of radiofrequency thermal rhizotomy could reach the triangular plexus when an electrode tip was placed on the petroclival junction. The grossly measured average triangular plexus vertical and transverse diameters were 0.8 cm and 1.3 cm, respectively.

LIMITATION

Only radiologic landmark was used to confirm the location of the electrode tip. However, further study confirming the location of the electrode tip under the guidance of electrical stimulation is needed.

CONCLUSION

When an electrode tip was placed on the petroclival junction, 53% of radiofrequency thermal rhizotomy could reach the triangular plexus.

The Efficacy and Safety of the Application of Pulsed Radiofrequency, Combined With Low-Temperature Continuous Radiofrequency, to the Gasserian Ganglion for the Treatment of Primary Trigeminal Neuralgia: Study Protocol for a Prospective, Open-Label, Parall

BACKGROUND

Trigeminal neuralgia is a very painful condition, and radiofrequency therapy is reserved for patients who are resistant or intolerant to pharmacologic therapy. Continuous radiofrequency (CRF) and pulsed radiofrequency (PRF) both have advantages and disadvantages. Recently, studies have found that PRF combined with low-temperature (< 65°C) CRF increases the efficacy of treatment, without leading to a significant increase in complications caused by nerve lesions. However, these reports have some limitations.

OBJECTIVES

We plan to conduct a randomized, controlled study to compare the efficacy of applying high-voltage PRF, with and without low-temperature CRF, to the Gasserian ganglion for the treatment of trigeminal neuralgia.

STUDY DESIGN

A study protocol for a prospective, open-label, parallel, randomized controlled trial (clinicaltrials.gov; NCT04174443).

SETTING

The Department of Pain Management, Beijing Tiantan Hospital, Capital Medical University in Beijing, China.

METHODS

One hundred forty-six patients with primary trigeminal neuralgia will be randomly assigned to 1 of 2 groups using an allocation ratio of 1:1. In the high-voltage PRF combined with low-temperature CRF group, 2 Hz of PRF will be applied under the following conditions: a voltage of 70 V, temperature of 42°C, pulse width of 20 ms, and treatment time of 600 s. Low-temperature CRF will then be performed at 60°C, with a treatment time of 270 s. In the high-voltage PRF group, only high-voltage PRF will be performed, using the same treatment parameters. Follow-up process will last for a duration of 1 year.

RESULTS

The primary outcome will be the effectiveness of the treatment after 12 months, which is the percentage of patients with a modified Barrow Neurological Institute Pain Intensity Score (BNI) between I and III. The secondary outcome will include the following: BNI score, Numeric Rating Scale, dose of carbamazepine or oxcarbazepine, patient satisfaction score, quality of life, numbness, side effects, and adverse reactions. These will be recorded over a 1-year follow-up period.

LIMITATIONS

The open-label study design may influence the measurement of outcomes and introduce bias, for example, performance or ascertainment bias.

CONCLUSIONS

To our knowledge, this will be the first prospective, open-label, parallel, randomized controlled trial to compare the efficacy and safety of the application of high-voltage PRF, combined with and without low-temperature (60°C) CRF, for the patients who have failed to respond to pharmacologic treatments for primary trigeminal neuralgia. If proven effective, this will be an important, safe, minimally destructive alternative treatment modality for primary trigeminal neuralgia following an ineffective conservative treatment.

Repetitive percutaneous radiofrequency thermocoagulation for persistent idiopathic facial pain and central neuropathic pain attributed to multiple sclerosis-a retrospective monocentric analysis

BACKGROUND

Persistent idiopathic facial pain (PIFP) is a debilitating chronic pain condition with pain radiating to trigeminal dermatomes. Typically, there are no pathological findings that can be identified during workup and therapy is symptomatic. Facial pain is common in patients with multiple sclerosis (central neuropathic pain attributed to MS). Our aim was to evaluate the effectiveness of percutaneous radiofrequency thermocoagulation (PRTC) of the gasserian ganglion and the duration of pain relief, as well as the identification of factors associated with its outcome.

METHODS

Data on all the above-mentioned patients that have been treated with PRTC between 2009 and 2019 were included into the study. The outcome was assessed with a six-tiered score from 1 (complete remission) to 6 (no benefit). Univariate and multivariate analyses were performed in order to obtain factors associated with the outcome.

RESULTS

A total of 52 patients were included. The total number of procedures performed was 114. 61.5% of patients who experienced temporary pain relief that lasted for a median of 60 days (range 3-1490 days). In patients with recurrence, the fraction of successful interventions was higher, and also transient, with successful pain amelioration in over 80% of patients. Successful responses to PRTC were observed in 27.9% after 1 year, 19.4% after 2 years, and 8.3% after 3 years. The only independent variable predicting pain relief was a repeat intervention with a history of ≥ 2 interventions (OR: 4.36, 95%-CI: 1.34-14.34, p = 0.015). No severe complications occurred.

CONCLUSIONS

Our data showed good and immediate pain relief after PRTC in the majority of our patients. PRTC is a low-risk procedure that can be discussed as an option in case of failure of medical treatment even in critically ill patients and can be repeated with good results when necessary. Long-term pain amelioration, even with repeated procedures, was not possible and no patient was permanently cured.

Trigeminal neuralgia secondary to multiple sclerosis: from the clinical picture to the treatment options

BACKGROUND

Trigeminal neuralgia is one of the most characteristic and difficult to treat neuropathic pain conditions in patients with multiple sclerosis. The present narrative review addresses the current evidence on diagnostic tests and treatment of trigeminal neuralgia secondary to multiple sclerosis.

METHODS

We searched for relevant papers within PubMed, EMBASE and the Cochrane Database of Systematic Reviews, taking into account publications up to December 2018.

RESULTS

Trigeminal neuralgia secondary to multiple sclerosis manifests with facial paroxysmal pain triggered by typical manoeuvres; neurophysiological investigations and MRI support the diagnosis, providing the definite evidence of trigeminal pathway damage. A dedicated MRI is required to identify pontine demyelinating plaques. In many patients with multiple sclerosis, neuroimaging and surgical evidence suggests that neurovascular compression might act in concert with the pontine plaque through a double-crush mechanism. Although no placebo-controlled trials have been conducted in these patients, according to expert opinion the first-line therapy for trigeminal neuralgia secondary to multiple sclerosis relies on sodium-channel blockers, i.e. carbamazepine and oxcarbazepine. The sedative and motor side effects of these drugs frequently warrant an early consideration for neurosurgery. Surgical procedures include Gasserian ganglion percutaneous techniques, gamma knife radiosurgery and microvascular decompression in the posterior fossa.

CONCLUSIONS

The relatively poor tolerability of the centrally-acting drugs carbamazepine and oxcarbazepine highlights the need to develop new selective and better-tolerated sodium-channel blockers. Prospective studies based on more advanced neuroimaging techniques should focus on how trigeminal anatomical abnormalities may be able to predict the efficacy of microvascular decompression.

Percutaneous trigeminal ganglion radiofrequency thermocoagulation alleviates anxiety and depression disorders in patients with classic trigeminal neuralgia: A cohort study

Trigeminal neuralgia (TN) is a neurological condition that presents as excruciating facial pain. Depression and anxiety are commonly associated with TN; however, anxiety and depression disorders in patients with TN and the effects of the various therapeutic strategies for TN on these disorders are not well studied.To evaluate depression and anxiety in patients with trigeminal neuralgia (TN), identify factors that predict their occurrence and study the effect of the percutaneous trigeminal ganglion radiofrequency thermocoagulation (PRT) procedure for alleviating pain on depression and anxiety.Patients with classic TN, who received PRT treatment, were consecutively recruited between October 2014 and October 2015. Severity of pain was determined using the visual analogue scale (VAS) score. Beck Depression Inventory-II (BDI) and Beck anxiety Inventory (BAI) were used to evaluate depression and anxiety disorders pre- and post-PRT. Medical, demographic, and psychosocial backgrounds were also assessed as predictive factors. A BDI score of ≥14 represented depression and BAI score of ≥45 represented anxiety. VAS, BDI, and BAI scores were collected at the time of admission and on the day of discharge.Of the 167 patients who participated in the study, 121 (72.5%) had depression and 34 (20.4%) suffered anxiety. Pre-PRT procedure, female sex, age >50 years, ineffective treatment, and high pain intensity (VAS ≥7) predicted the development of depression and anxiety. Post-PRT procedure, all patients who experienced pain relief also reported amelioration of depression and anxiety.A considerable percentage of patients with TN developed depression and anxiety. Patients who were female, older than 50 years, or suffered from failure treatment and severe pain (VAS>7), were at higher risk of depression and anxiety development. Complete alleviation of pain by using surgical PRT could immediately attenuate depressive and anxiety disorders associated with TN.

Percutaneous radiofrequency thermocoagulation for trigeminal neuralgia using neuronavigation-guided puncture from a mandibular angle

Percutaneous radiofrequency thermocoagulation (RFT) of the Gasserian ganglion is an effective treatment for primary trigeminal neuralgia (pTN). Currently Hartel anterior approach is the most commonly used method to access the Gasserian ganglion. However, this approach is associated with high recurrence rate and technical difficulties in certain patients with foramen ovale (FO) anatomical variations. In the present study, we assessed the feasibility of accessing the Gasserian ganglion through the FO from a mandibular angle under computed tomography (CT) and neuronavigation guidance.A total of 108 patients with TN were randomly divided into 2 groups (Group G and Group H) using a random number table. In Group H, Hartel anterior approach was used to puncture the FO; whereas in Group G, a percutaneous puncture through a mandibular angle was used to reach the FO. In both groups, procedures were guided by CT imaging and neuronavigation. The success rates, therapeutic effects, complications, and recurrence rates of the 2 groups were compared.The puncture success rates in Group H and Group G were 52/54 (96.30%) and 49/54 (90.74%), respectively (P = 0.24). The 2 procedural failures in Group H were rescued by using submandibular trajectory, and the 5 failures in Group G were successfully reapproached by Hartel method. Therapeutic effects as measured by Barrow Neurological Institute (BNI) pain scale (P = 0.03) and quality of life (QOL) scores (P = 0.04) were significantly better in Group G than those in Group H at 36 months posttreatment. Hematoma developed in 1/54 (1.85%) cases in Group H, and no cases of hematoma were observed in Group G (P = 0.33). In Group H, RFT resulted in injury to the unintended trigeminal nerve branches and motor fibers in 27/52 (51.92%) cases; in Group G, it resulted in the same type of injury in 7/49 cases (14.29%) (P < 0.01). In Group H, the 24- and 36-month recurrence rates were 12/51 (23.53%) and 20/51 (39.22%), respectively; in Group G, these recurrence rates were 7/49 (12.24%) and 9/49 (16.33%, P = 0.03), respectively.CT- and neuronavigation-guided puncture from a mandibular angle through the FO into the Gasserian ganglion can be safely and effectively used to deliver RFT for the treatment of pTN. This method may represent a viable option to treat TN in addition to Hartel approach.

Laser speckle imaging to improve clinical outcomes for patients with trigeminal neuralgia undergoing radiofrequency thermocoagulation

OBJECTIVE

Percutaneous treatments for trigeminal neuralgia are safe, simple, and effective for achieving good pain control. Procedural risks could be minimized by using noninvasive imaging techniques to improve the placement of the radiofrequency thermocoagulation probe into the trigeminal ganglion. Positioning of a probe is crucial to maximize pain relief and to minimize unwanted side effects, such as denervation in unaffected areas. This investigation examined the use of laser speckle imaging during probe placement in an animal model.

METHODS

This preclinical safety study used nonhuman primates, Macaca nemestrina (pigtail monkeys), to examine whether real-time imaging of blood flow in the face during the positioning of a coagulation probe could monitor the location and guide the positioning of the probe within the trigeminal ganglion.

RESULTS

Data from 6 experiments in 3 pigtail monkeys support the hypothesis that laser imaging is safe and improves the accuracy of probe placement.

CONCLUSIONS

Noninvasive laser speckle imaging can be performed safely in nonhuman primates. Because improved probe placement may reduce morbidity associated with percutaneous rhizotomies, efficacy trials of laser speckle imaging should be conducted in humans.

[The evaluation of curative effect of radiofrequency thermocoagulation on semilunar ganglion of aged patients with recurrent trigeminal neuralgia]

OBJECTIVE

To investigate curative effect and importance of radiofrequency thermocoagulation onsemilunar ganglion of aged patients with recurrent trigeminal neuralgia.

METHOD

112 cases with recurrent trigeminal neuralgia were performed with radiofrequency thermocoagulation on semilunar ganglion by puncture through skin under local anesthesia.

RESULT

The maintaining effective duration in 112 cases was 7.3 ± 1.3 years after primary therapy. After the first thermocoagulation, 89.28% (100/112) patients got the relief from pain immediately, 8 (7.14%) cases also recieved the same effect after twice treatment. However two cases (2.6%) had no effects. The total effective rate was 98.21%. During five follow-up years, VAS scores, dose of carbamazepine and satisfaction were better than those before the treatment. The effective rate was still over 57.5% within three years after the treatment. The recurrent risk increased obviously from 40 months after the treatment by Kaplan-Meier method.

CONCLUSION

Semilunar ganglion of radiofrequency thermocoagulation was an ideal option for old-age patients with trigeminal neuralgia. It can be performed repeatedly.

Trigeminal Ganglion Stimulation

Facial pain in the distribution of the trigeminal nerve, commonly identified as trigeminal neuralgia, should not be confused with trigeminal neuropathic pain. The latter is caused by an accidental and nonintentional nerve lesion. When the first-line pharmacological treatment fails to provide satisfactory pain relief, surgical treatment, such as microvascular decompression and neurodestructive interventions (radiofrequency or cryotherapy), is not indicated. The logical choice of technique becomes neuromodulation, but it may be challenging to perform in the facial area. Although the initial results of trigeminal ganglion stimulation were promising, they often were of short duration because of lead migration and inadequate stimulation coverage in the trigeminal nerve distribution. To ensure accurate placement and proper anchoring, a custom-made electrode was developed and produced, and its stereotactic implantation is guided by electromagnetic navigation. This technique has been used at our center for several years; the published results show at least 30% of pain relief in 75% of the patients and considerable reduction in medication use.

[Treatment of trigeminal neuralgia: an update and future prospects of percutaneous techniques]

INTRODUCTION

Trigeminal neuralgia is one of the most severe facial pain syndromes. The annual incidence varies between 4-13% and has a significant effect on patients' quality of life. When the pain cannot be controlled by pharmacological treatment, several different surgical options can be considered. The choice of technique will be based on observational studies and its application depends on the experience of each centre.

AIMS

To assess the effectiveness and level of evidence of pharmacological and surgical treatment in trigeminal neuralgia, and to analyse the current role of percutaneous techniques in the treatment of this pathology.

DEVELOPMENT

The initial treatment of trigeminal neuralgia is pharmacological and carbamazepine is the only drug with a sufficiently high level of evidence. The percutaneous surgical techniques are effective and easy to apply, but the tendency for relapses to appear means there is a preference for vascular microdecompression. Yet, there are no reports of comparative studies that determine the superiority of a technique with a good level of evidence. The three most commonly used percutaneous techniques, balloon compression, glycerol rhizotomy and thermocoagulation by radiofrequency, were reviewed. This last technique is the one that has undergone the greatest development in recent years, with the emergence of neurophysiological techniques that make it possible to optimise results.

CONCLUSIONS

The selection of a surgical technique for use in trigeminal neuralgia does not have much backing from randomised clinical trials. The new procedures in the application of radiofrequency can improve the treatment prospects of this pathology.

PERCUTANEOUS BALLOON COMPRESSION OF GASSERIAN GANGLION FOR THE TREATMENT OF TRIGEMINAL NEURALGIA: AN EXPERIENCE FROM INDIA

Trigeminal neuralgia (TN) is characterized by unilateral, lancinating, paroxysmal pain in the dermatomal distribution area of trigeminal nerve. Percutaneous balloon compression (PBC) of Gasserian ganglion is an effective, comparatively cheaper and simple therapeutic modality for treatment of TN. Compression secondary to PBC selectively injures the large myelinated A-alfa (afferent) fibers that mediate light touch and does not affect A-delta and C-fibres, which carry pain sensation. Balloon compression reduces the sensory neuronal input, thus turning off the trigger to the neuropathic trigeminal pain. In this current case series, we are sharing our experience with PBC of Gasserian Ganglion for the treatment of idiopathic TN in our patients at an academic university-based medical institution in India. During the period of August 2012 to October 2013, a total of twelve PBCs of Gasserian Ganglion were performed in eleven patients suffering from idiopathic TN. There were nine female patients and two male patients with the age range of 35-70 years (median age: 54 years). In all patients cannulation of foramen ovale was done successfully in the first attempt. In eight out of eleven (72.7%) patients ideal 'Pear-shaped' balloon visualization could be achieved. In the remaining three patients (27.3%), inflated balloon was 'Bullet-shaped'. In one patient final placement of Fogarty balloon was not satisfactory and it ruptured during inflation. This case was deferred for one week when it was completed successfully with 'Pear-shaped' balloon inflation. During the follow up period of 1-13 months, there have been no recurrences of TN. Eight out of eleven patients (72.7%) are completely off medicines (carbamazepine and baclofen) and other two patients are stable on very low doses of carbamazepine. All patients have reported marked improvement in quality of life. This case series shows that percutaneous balloon compression is a useful minimally invasive intervention for the treatment of trigeminal neuralgia.

[Controlled clinical study of trigeminal ganglion puncture guided by CT/MRI image fusion interface navigation]

OBJECTIVE

To build the radio-frequency thermocoagulation (RFT) interface under navigation including foramen ovale and trigeminal ganglion based on CT/MRI image fusion technology, to visualize the relationship between the trigeminal ganglion and the puncture needle, and to observe clinical effects of this method.

METHODS

CT and MRI data of 20 trigeminal neuralgia patients which were input into BrainLAB-iPlan navigation planning system, were aligned and merged, so that the 3-dimentional image fusion interface of CT and MRI for puncture was built. According to the image fusion interface, the pathways targeting the trigeminal ganglion were planned to assist trigeminal ganglion puncture and RFT. The treatment consequences were observed and compared with 20 patients under the RFT only with the direction of pre- and intra-operative CT.

RESULTS

In the group of CT/MRI image fusion cases, 3 cases had been predicted to be difficult because of unreachable ganglion through the foramen ovale pathway. The postoperative clinical examination proved that the ganglions of these 3 cases were only insufficiently damaged or undamaged. The other 17 cases proved better results, except 2 cases whose treatment was changed in operation. The valid rates for both image fusion navigation group and CT group were all above 95%.

CONCLUSION

Navigation interface including both foramen ovale and trigeminal ganglion based on CT/MRI image fusion made visualization of the pathway targeting ganglion come true, which made the treatment more accurate and individual. Whether the pathway could reach the ganglion might distinguish the trouble cases from others.

[Differential diagnosis between melanotic schwannoma of gasserian ganglion and metastatic melanoma of middle cranial fossa]

We present a case of a rare tumor--melanotic schwannoma of trigeminal nerve root and gasserian ganglion. Differential diagnosis between metastatic melanoma and melanotic schwannoma (MS) is associated with serious difficulties and high responsibility. Metastatic melanoma is a high grade tumor while most MS are benign lesions with good outcome. By the date 105 cases of these tumors are described in the world literature, 3 of them originated from trigeminal nerve root and gasserian ganglion. MS predominantly occur in relatively young patients, they are characterized by presence of Carney's complex and psammomatous bodies and absence of primary focus. MS and metastatic melanoma have similar appearance on MRI due to presence of melanin granules. Indirect signs evident for MS include cystic structure and dumbbell-shaped growth. Metastatic melanoma of cranial nerves is more typical in people older than 40, primary focus in the face in the zone of innervation of affected nerve is common. In case of absence of the listed features differential diagnosis is based on immunohistochemical analysis and electron microscopy of tissue samples.

Neurosurgical interventions for the treatment of classical trigeminal neuralgia

BACKGROUND

Surgical interventions are used for trigeminal neuralgia when drug treatment fails. Surgical treatments divide into two main categories, ablative (destructive) or non-ablative. These treatments can be done at three different sites: peripherally, at the Gasserian ganglion level, and within the posterior fossa of the skull.

OBJECTIVES

To assess the efficacy of neurosurgical interventions for classical trigeminal neuralgia in terms of pain relief, quality of life and any harms. To determine if there are defined subgroups of patients more likely to benefit.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Specialized Register, (13 May 2010), CENTRAL (issue 2, 2010 part of the Cochrane Library), Health Technology Assessment (HTA) Database, NHS Economic Evaluation Database (NHSEED) and Database of Abstracts of Reviews of Effects (DARE) (issue 4, 2010 (HTA, NHSEED and DARE are part of the Cochrane Library)), MEDLINE (January 1966 to May 2010) and EMBASE (January 1980 to May 2010) with no language exclusion.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials of neurosurgical interventions used in the treatment of classical trigeminal neuralgia.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted authors for clarification and missing information whenever possible.

MAIN RESULTS

Eleven studies involving 496 participants met some of the inclusion criteria stated in the protocol. One hundred and eighty patients in five studies had peripheral interventions, 229 patients in five studies had percutaneous interventions applied to the Gasserian ganglion, and 87 patients in one study underwent two modalities of stereotactic radiosurgery (Gamma Knife) treatment. No studies addressing microvascular decompression (which is the only non-ablative procedure) met the inclusion criteria. All but two of the identified studies had a high to medium risk of bias because of either missing data or methodological inconsistency. It was not possible to undertake meta-analysis because of differences in the intervention modalities and variable outcome measures. Three studies had sufficient outcome data for analysis. One trial, which involved 40 participants, compared two techniques of radiofrequency thermocoagulation (RFT) of the Gasserian ganglion at six months. Pulsed RFT resulted in return of pain in all participants by three months. When this group were converted to conventional (continuous) treatment these participants achieved pain control comparable to the group that had received conventional treatment from the outset. Sensory changes were common in the continuous treatment group. In another trial, of 87 participants, investigators compared radiation treatment to the trigeminal nerve at one or two isocentres in the posterior fossa. There were insufficient data to determine if one technique was superior to another. Two isocentres increased the incidence of sensory loss. Increased age and prior surgery were predictors for poorer pain relief. Relapses were nonsignificantly reduced with two isocentres (risk ratio (RR) 0.72, 95% confidence intervaI (CI) 0.30 to 1.71). A third study compared two techniques for RFT in 54 participants for 10 to 54 months. Both techniques produced pain relief (not significantly in favour of neuronavigation (RR 0.70, 95% CI 0.46 to 1.04) but relief was more sustained and side effects fewer if a neuronavigation system was used. The remaining eight studies did not report outcomes as predetermined in our protocol.

AUTHORS' CONCLUSIONS

There is very low quality evidence for the efficacy of most neurosurgical procedures for trigeminal neuralgia because of the poor quality of the trials. All procedures produced variable pain relief, but many resulted in sensory side effects. There were no studies of microvascular decompression which observational data suggests gives the longest pain relief. There is little evidence to help comparative decision making about the best surgical procedure. Well designed studies are urgently needed.

Cardiovascular response during trigeminal ganglion compression for trigeminal neuralgia according to the use of local anesthetics

OBJECTIVES

There are controversies about the use of local anesthetics during balloon compression for trigeminal neuralgia (TN) as a protective factor for cardiovascular events. The objective of this study was to investigate cardiovascular parameters (blood pressure and heart rate [HR]) of patients that underwent trigeminal balloon compression with local anesthetics compared to a control group (placebo).

METHODS

This is a randomized controlled study; 55 patients were randomized into two groups: study (deep sedation and trigeminal block with 0.8-mL lidocaine 2%) and control group (deep sedation and trigeminal injection of 0.8-mL saline). Blood pressure and HR were measured in five distinct moments: preoperative, during puncture for local anesthesia/placebo, during puncture with the catheter, during balloon compression, and final evaluation. Statistical analysis was performed with Pearson's chi (2) and McNemar tests and the analysis of variance for repetitive measures.

RESULTS

The means of systolic and diastolic blood pressures (SBP and DBP, respectively) were higher in the control group when compared to the study group at the evaluation during puncture with the catheter (p < 0.001) and balloon compression (p < 0.001 and p = 0.018 for DBP and SBP, respectively). There was an increase in the HR in the control group during the procedure (p = 0.017).

CONCLUSION

The use of local anesthetics during the trigeminal balloon compression for TN can have a preventive role for the risk of cardiovascular events.

Anterior Segment Growth and Peripheral Neural Pathways in Chick

PURPOSE

To learn if peripheral nerve pathways are necessary for corneal expansion and anterior segment growth under a 12-hr light:dark cycle or for the inhibition of corneal expansion under constant light rearing.

METHODS

Recently hatched White Leghorn chicks under anesthesia received unilateral ciliary ganglionectomy (CGx), cranial cervical ganglionectomy (Sx), or section of the ophthalmic nerve (TGx), along with sham-operated and/or never-operated control cohorts. Chicks were reared postoperatively under either a 12-hr light:dark cycle or under constant light. After 2 weeks and with the chicks under anesthesia, corneal radii of curvature and diameters were obtained with a photokeratoscope, refractometry and A-scan ultrasonography were performed, and the axial and equatorial dimensions of enucleated eyes were measured with digital calipers. Corneal areas were calculated from corneal curvatures and diameters.

RESULTS

Despite the rich peripheral innervation to the eye, the selective denervations performed here exerted remarkably limited effects on corneal expansion and anterior segment development in chicks reared under either lighting condition. Ophthalmic nerve section did reverse in large part the inhibition of equatorial expansion of the vitreous chamber occurring under constant light rearing.

CONCLUSIONS

The ciliary, sympathetic, or ophthalmic peripheral nerve pathways to the eye are not required either for corneal expansion and anterior segment development under a 12-hr light:dark cycle or for the inhibition of corneal expansion under constant light rearing. The ocular sensory innervation may be a means for regulating vitreous cavity shape.

Meningitis after percutaneous radiofrequency trigeminal ganglion lesion. Case report and review of literature

CASE REPORT

A 79-year-old man with severe trigeminal neuralgia presented to the pain clinic, and was offered a radiofrequency trigeminal ganglion lesion. He had only partial response to the first procedure, so a second was undertaken. The following day he presented with signs of meningitis and the diagnosis was confirmed on lumbar puncture. He was treated with appropriate antibiotics, and recovered well.

LITERATURE REVIEW

The current literature on reports of meningitis after percutaneous trigeminal ganglion lesioning reveals an overall mean incidence of meningitis of 0.15% (confidence interval 0.10-0.21). The Scottish Intercollegiate Guidelines Network guide the decision on the routine use of antimicrobial prophylaxis, and although the risk of infection can be estimated from the literature and the severity of infection is high, the effectiveness and consequences of prophylaxis cannot be established.

CONCLUSION

If breach of the oral mucosa has occurred, then antibiotic prophylaxis should be administered.

Review of complications due to foramen ovale puncture

We aim to evaluate the mechanisms responsible for complications during trigeminal rhizotomy via foramen ovale puncture. Ten dry skulls and 10 skull-base specimens were investigated in the present study. In cadaveric skull-base specimens, the anatomical relationships between the foramen ovale, mandibular nerve and Gasserian ganglion and the surrounding neurovascular structures were investigated intradurally. The distance between the foramen ovale and Gasserian ganglion was measured as 6 mm. The abducent nerve, adjacent to the anterior tail of the petrolingual ligament, was observed passing along the lateral wall of the cavernous sinus. Advancement of the catheter more than 10 mm from the foramen ovale is likely to damage the internal carotid artery and the abducent nerve at the medial side of the petrolingual ligament. Thermocoagulation of the lateral wall of the cavernous sinus may damage the cranial nerves by heat, giving rise to pareses.

INTRACAVERNOUS TRIGEMINAL GANGLION AMYLOIDOMA

OBJECTIVE

Isolated amyloidomas rarely manifest in nervous system tissues. To the authors' knowledge, there have been 52 documented cases of primary amyloid tumors of the central nervous system and closely associated structures. The authors present a case of a woman with a history of presumptive trigeminal neuralgia who was found to have an amyloidoma of the trigeminal ganglion.

CLINICAL PRESENTATION

A 32-year-old Caucasian patient presented with a chief complaint of severe numbness and pain throughout the right side of her face. Her symptoms had been progressive over the previous 3 years. Medical management of her presumptive diseases with Zoloft (Pfizer Inc., New York, NY) and Neurontin (Pfizer Inc.) failed to improve or halt her right facial numbness and pain. Brain magnetic resonance imaging was acquired, demonstrating abnormal contrast enhancement and enlargement of the right trigeminal ganglion. The lesion abutted and indented the right internal carotid artery and extended from Meckel's cave into the inferior cavernous sinus and distally to the foramen ovale.

INTERVENTION

The patient underwent a right frontotemporal craniotomy for resection of the gasserian ganglion lesion. A delicate incision was made in the wall of the cavernous sinus, allowing confirmatory biopsy of the lesion. With the site of the tumor within the cavernous sinus verified by pathology, the remainder of the tumor was removed. A final pathological review of the resected tumor confirmed a diagnosis of amyloidoma of the trigeminal ganglion.

CONCLUSION

We present the case of a patient with a rare trigeminal ganglion amyloidoma that closely mimicked idiopathic trigeminal neuralgia. Even in the absence of systemic signs of amyloidosis, this benign protein deposition disease should be considered in the differential for atypical dysesthesias of the trigeminal dermatomes. Furthermore, central and peripheral nervous system amyloidomas respond well to surgical resection and rarely recur.

Masticatory problems after balloon compression for trigeminal neuralgia: a longitudinal study

Idiopathic trigeminal neuralgia (ITN) is a chronic neuropathic pain that affects the masticatory system. The objective of this study was to identify orofacial pain and temporomandibular characteristics, including temporomandibular disorder (TMD), in a sample of 105 ITN patients treated with compression of the trigeminal ganglion. The evaluations occurred before, 7, 30 (1 month), 120 (3 months) and 210 days (7 months) after surgery. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), the Clinical Questionnaire (EDOF-HC) and Helkimo Indexes were used. Findings before neurosurgery were used as control for parameters. McNemar test and variance analysis for repetitive measurements were used for statistical analysis; 45.3% of the edentulous patients presented severe dental occlusion index; numbness was an important masticatory complaint in 42.6%; mastication became bilateral, but its discomfort continued during all period; headache and body pain reduced after surgery; TMD, present in 43.8% before surgery, increased but normalized after 7 months; jaw mobility compromise was still present, but daily activities improved after 7 months. We concluded that: (i) ITN relief reduced headache, body pain, depression and unspecific symptoms; and (ii) TMD before surgery and at 7 months suggests that this may be a contributory factor to patients' pain complaints.

Impact of radiosurgery on the surgical treatment of trigeminal neuralgia

BACKGROUND

The history of the development of current available techniques to treat TN was reviewed.

METHODS

The largest peer-reviewed publications on the surgical treatment of refractory TN were analyzed, considering the pros and cons of each technique. Results of modern peer-reviewed radiosurgery series were presented, taking into consideration the approach of each research article. Radiation doses and targets for radiosurgery were discussed to maximize the understanding of this technique.

RESULTS

It is concluded that radiosurgery is the least invasive modality with the fewest side effects, although, to match the results of the competing techniques, a substantial number of patients still need some medication intake.

CONCLUSION

Further studies determining the ideal target and radiation dose may bring radiosurgery results to the level of the ones achieved with microvascular decompression, currently considered the gold-standard method.

Neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of intractable trigeminal neuralgia

BACKGROUND

Percutaneous radiofrequency thermocoagulation of the trigeminal ganglion (PRTTG) is regarded as the first choice for most patients with trigeminal neuralgia (TN) because of its safety and feasibility. However, neuronavigator-guided PRTTG has been seldom reported. The purpose of this study was to assess the safety and efficacy of neuronavigator-guided PRTTG for the treatment of intractable TN.

METHODS

Between January 2000 and December 2004, 54 patients with intractable TN were enrolled into this study and were randomly divided into two groups. The patients in navigation group (n = 26) underwent PRTTG with frameless neuronavigation, and those in control group (n = 28) received PRTTG without neuronavigation. Three months after the operation, the efficacy, side effects, and complications of the surgery were recorded. The patients in the control group were followed up for 10 to 54 months (mean, 34 +/- 5), and those in the navigation group were followed up for 13 to 58 months (mean, 36 +/- 7). Kaplan-Meier analyses of the pain-free survival curves were used for the censored survival data, and the log-rank test was used to compare survival curves of the two groups.

RESULTS

The immediate complete pain-relief rate of the navigation group was 100%, whereas it was 95% in the control. The proportion of sustained pain-relief rates at 12, 24 and 36 months after the procedure were 85%, 77%, and 62% in the navigation group, and 54%, 40%, and 35% in the control. Recurrences in the control group were more common than that in the navigation group. Annual recurrence rate in the first and second years were 15% and 23% in the navigation group, and 46%, 60% in the control group. No side-effect and complication was noted in the navigation group except minimal facial hypesthesia.

CONCLUSION

Neuronavigator-guided PRTTG is a safe and promising method for treatment of intractable TN with better short- and long-term outcomes and lower complication rate than PRTTG without neuronavigation.

A model for foramen ovale puncture training: Technical note

BACKGROUND

Trigeminal neuralgia is a common cause of facial pain, characterized by shock-like pain affecting one or more branches of the trigeminal nerve. When conservative treatment fails and microdecompression is not indicated, percutaneous procedures are helpful. This percutaneous approach is done by a puncture up to the Gasserian ganglion, through the foramen ovale. Although simple and safe, this puncture demands some expertise from neurosurgeons. For that, a partnership between neurosurgeons and bio-engineers has developed a model for foramen ovale puncture, allowing practice for residents and young neurosurgeons.

METHOD

A model for foramen ovale puncture has been created by interposition of synthetic materials over a skull, simulating the human face.

FINDINGS

This model has shown great similarity with that found in conventional surgeries, even upon repeated testing by experienced functional neurosurgeons and young residents.

CONCLUSION

This model for foramen ovale puncture training has demonstrated valuable help for initial practicing of this common neurosurgical procedure, particularly in centers where there are not many cadavers available for training.

Sensory denervation modulates eIF-2 alpha kinase expression in the rabbit lacrimal gland

PURPOSE

To investigate the hypothesis that sensory denervation of the rabbit lacrimal gland results in dysregulation of protein synthesis. We used differential display of mRNA to identify genes associated with protein synthesis and secretion that may be altered in this situation.

METHODS

New Zealand white rabbits underwent unilateral sensory denervation by the ablation of the trigeminal ganglion. After 7 days, the denervated and contralateral control lacrimal glands were removed. The effects of denervation on gene expression were carried out using differential mRNA display. Northern and Western blot analyses were used to verify differential gene expression.

RESULTS

Differential mRNA display identified the gene heme-regulated inhibitor eukaryotic initiation factor-2 alpha kinase (HRI eIF-2a kinase) in the lacrimal gland, the expression of which was reduced in the denervated lacrimal gland. The sequenced fragment from differential display showed 94% identity to rabbit HRI eIF-2a kinase. The decreased expression of HRI eIF-2a kinase was confirmed by Northern and Western blots, and measurement of HRI eIF-2a kinase phosphorylation activity in the lacrimal gland after ablation of sensory neurons showed that it was significantly decreased compared with that of normal and control lacrimal glands.

CONCLUSIONS

The results suggest that loss of sensory innervation has a role in the lacrimal gland, contributing to the expression of HRI eIF-2a kinase, a pivotal negative regulator of protein synthesis. A reduction in control of protein synthesis may lead to the translation of repressed messages associated with cell stress responses.

[Algological treatment of trigeminal neuralgia. Experience of 15 years]

BACKGROUND

We present the experience in the treatment of trigeminal neuralgia (TN) during 15 years in one institute, evaluating epidemiological variables and clinical presentation, and comparing the results obtained with different treatments available.

METHODS

A retrospective, descriptive study was carried out by reviewing cases diagnosed by the Neurology Service, such as TN, and treated by the Pain Medicine and Palliative Care Unit of the Insituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubíran," from January 1, 1998 to December 31, 2003. Age, sex, type of neuralgia, anatomical site affected and intensity of pain were evaluated by means of the Analogue Visual Scale (AVS). The following treatments were evaluated (pharmacologic, surgical, and blockade of Gasser ganglion). Descriptive statistics, linear regression and bivariate correlation were used (statistical package SPSS).

RESULTS

Fifty two cases were studied with a female predominance (2:1). Average age was 60 years. Clinical presentation most frequently was typical neuralgia (51.9%), right predominance (59.6%) and affected branch V2 (50%). In 88%, pharmacological treatment was used. The reduction of pain was 74% in all cases, with r-.765 for the pharmacological treatment, r-.715 in the blockade of the Gasser ganglion, and r-.901 for surgical treatment (p < 0.01).

CONCLUSIONS

In the experience of the INCMNSZ, treatment of choice in most cases of TN is pharmacological, with surgical treatment useful in cases where vascular alterations were identified.

[Idopathic tigeminal neuralgia--radiofrequency rhizotomy of ganglion Gasseri]

Idiopathic trigeminal neuralgia (ITN), (tic dou-loureux), may be defined as a chronic painfull disorder of the sensory divisions of the trigeminal nerve, with unexplained cause and pathogenesis. The clinical features are characterized by recurrent paroxysmal lancinating pain confined to distribution of one or more branches of the nerve. Radiofrequency rhizotomy (RFR) of ganglion Gasseri is a methode of choise in treatment of ITN. We present the series of 1600 patients suffering from ITN who underwent RFR between 1984 and 2001. Ages ranged from 29 to 88 years, with a mean age of 62 years. Total pain relief immediately after a single radiofrequency lesion was achieved in 1469 (92%) of patients. After one year a recurrence of pain was present in 145 (10%). Age, sex and duration of illness were unrelated to outcome. Patients previously treated by open surgery appeared to receive less benefit from subsequent RFR. Clinical outcome correlated with the degree of sensory deficit created by RFR. Patients acquiring dense deficit demonstrated a reduced risk of recurrence: 203/1129 (18%) of patients with dense sensory loss and 75/258 (29%) of those with a partial deficit developed a recurrence by three years, whereas almost all patients (78/82) without initial sensory loss suffered a recurrence by three years. Serious complications resulting from RFR were infrequent and the most common was the permanent dysesthesia in 9 (0.6%) of patients. Our results suggest that the RFR is an well bearable and effective longterm surgical treatment for ITN, especially for older and poor-risk patients.

Re-evaluation and quantification of the different sources of nerve fibres supplying the rat eye

The denervation and/or the removal of peripheral nerve ganglia are useful surgical techniques for studying the source and distribution of peripheral nerves in all organs, including the eye. The amount and distribution of the remaining nerve fibres supplying the eye (after sectioning of various types of nervous fibres and/or removal of nerve ganglia) were evaluated in the rat. Male Sprague-Dawley rats were anaesthetized and one or more of the following nervous tissues were removed: superior cervical ganglion, main ciliary ganglion, pterygopalatine ganglion, trigeminal ganglion and the ophthalmic-maxillary nerve. In some animals, chemical sympathectomy was performed by administration of 6-OH dopamine. The eyes were cut in serial sections, but only three regions (cornea, iris and choroid) were harvested and submitted for various nerve fibre staining techniques. The results were quantified and statistically analysed. Superior cervical ganglionectomy and/or chemical sympathectomy induced the destruction of almost all the catecholaminergic nerve fibres in the three examined regions of the rat eye. Removal of the ciliary ganglion (partial parasympathectomy) caused the destruction of about 60% of the cholinergic nerve fibres of the same regions of the rat eye, while subtotal parasympathectomy destroyed about 80% of the cholinergic nerve fibres. Surgical transsection of the ophthalmo-maxillary nerve or the removal of the trigeminal ganglion led to a degeneration of almost all sensitive nerve fibres of the three examined regions of the rat eye. The denervation experiments confirmed the presence of the different types of nerve fibres (sympathetic, parasympathetic and sensitive) in the three studied structures of the rat eye.

Acute subdural and intratemporal hematoma as a complication of percutaneous compression of the gasserian ganglion for trigeminal neuralgia

The case of a 68 year-old man who developed a fatal intracranial hemorrhagic complication following percutaneous compression of the gasserian ganglion for trigeminal neuralgia is reported. The complication was likely related to improper placement of the Fogarty catheter into the temporal fossa out of the Meckel's cave. The anatomical structures at risk of damage by misplaced needle or catheter and some relevant technical details aimed to prevent extratrigeminal complications related with this and other percutaneous trigeminal lesioning procedures are analyzed.

A rat model of radiofrequency ablation of trigeminal innervation via a ventral approach with stereotaxic surgery

Neurotrophic keratopathy (NK), a consequence of sensory denervation of the cornea, must be better understood in order to develop new approaches to therapy. The purpose of this study was to create a rat model for neurotrophic keratopathy by denervating the trigeminal nerve through a ventral approach with stereotaxic surgery. Stereotaxic coordinates were measured in 46 male Sprague Dawley rat cadavers for localization of V1. After further refining the coordinates in nine live animals, radiofrequency ablation was chosen as an effective method of disrupting the innervation to the cornea. Fifty-two live rats were treated with radiofrequency ablation to define the anatomical localization of the lesion by utilizing gross and histopathological studies. A gross lesion of the trigeminal nerve and/or ganglion was observed in 47 (90%) of the 52 animals. Histopathological studies revealed that all 52 animals had anatomical damage of the trigeminal innervation to the eye. Low mortality and little morbidity were observed in these animals. We have developed a rat model for neurotrophic keratopathy that is simple to produce, accurate in creating a lesion by utilizing stereotaxic techniques combined with radiofrequency ablation, and successful in decreasing morbidity and mortality.

Long-term relief of posttraumatic headache by sphenopalatine ganglion pulsed radiofrequency lesioning: a case report11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors(s) or upon any organization with which the author(s) is/are associated

Posttraumatic headache is a common and disabling pain syndrome in patients who sustain a head injury. Unfortunately, conventional treatments may fail or cause intolerable side effects. Because chronic headache may be mediated by central and peripheral neural processes, these structures may be therapeutic targets. One target, the sphenopalatine ganglion (SPG), is implicated in several headache disorders and has been lesioned for headache relief. Because of the risks of neurolytic procedures, nonablative procedures that provide pain relief would be useful. We present a case wherein a man in his late twenties with posttraumatic headache obtained more than 17 months of relief with SPG pulsed-mode radiofrequency lesioning. SPG pulsed-mode radiofrequency is a nonablative, neural lesioning method that may be useful in the treatment of posttraumatic headache.

Systematic Review of Ablative Neurosurgical Techniques for the Treatment of Trigeminal Neuralgia

OBJECTIVE

There are no randomized controlled trials comparing retrogasserian percutaneous radiofrequency thermocoagulation, glycerol rhizolysis, balloon compression of the gasserian ganglion, and stereotactic radiosurgery, nor are there systematic reviews using predefined quality criteria. The objective of this study was to systematically identify all of the studies reporting outcomes and complications of ablative techniques for treatment of trigeminal neuralgia, from the development of electronic databases, and to evaluate them with predefined quality criteria.

METHODS

Inclusion criteria for the outcome analysis included thorough demographic documentation, defined diagnostic and outcome criteria, a minimum of 30 patients treated and median/mean follow-up times of 12 months, not more than 20% of patients lost to follow-up monitoring, Kaplan-Meier actuarial analysis of individual procedures, less than 10% of patients retreated because of failure or early recurrence, and a minimal dose of 70 Gy for stereotactic radiosurgery. High-quality studies with no actuarial analysis were used for the evaluation of complications.

RESULTS

Of 175 studies identified, 9 could be used to evaluate rates of complete pain relief on a yearly basis and 22 could be used to evaluate complications. In mixed series, radiofrequency thermocoagulation offered higher rates of complete pain relief, compared with glycerol rhizolysis and stereotactic radiosurgery, although it demonstrated the greatest number of complications.

CONCLUSION

Radiofrequency thermocoagulation offers the highest rates of complete pain relief, although further data on balloon microcompression are required. It is essential that uniform outcome measures and actuarial methods be universally adopted for the reporting of surgical results. Randomized controlled trials are required to reliably evaluate new surgical techniques.

A rare case of cellular schwannoma involving the trigeminal ganglion

Cellular schwannomas rarely involve the cranial nerves, being more common in the spinal and peripheral nerves. A rare case of cellular schwannoma involving the gasserian ganglion, a hitherto unreported site, that extended infratentorially to present as a cerebellopontine angle tumor is reported. It is important to recognize that cellular schwannomas can histologically mimic malignant peripheral nerve sheath tumors because of their high cellularity and mitotic activity, but they are relatively benign tumors with a tendency to recur but not metastasize.

A method for intraoperative microneurographic recording of unitary activity in the trigeminal ganglion of patients with trigeminal neuralgia

The etiology of trigeminal neuralgia appears to be vascular compression of the nerve at the root entry zone. However, the physiologic mechanism of trigeminal neuralgia remains uncertain. To gain insight into the pathophysiology of the disorder, we developed a method for intraoperative microneurographic recordings from the trigeminal ganglion of patients with trigeminal neuralgia. The recordings are performed immediately prior to standard percutaneous trigeminal gangliolysis for pain relief. Spontaneous or evoked single- and multi-unit action potential activity can be recorded and the location of receptive fields determined. The method should facilitate the testing of hypotheses concerning the origin of this unique pain disorder.

Comparison of percutaneous trigeminal ganglion compression and microvascular decompression for the management of trigeminal neuralgia

This investigation evaluates the results of percutaneous trigeminal ganglion compression (PTGC) and compares them those for microvascular decompression (MVD) in treating trigeminal neuralgia. The authors report 127 cases of trigeminal neuralgia treated by PTGC and comparing the results with those of 114 patients whom underwent MVD from 1985 to 2000. The following parameters were compared: technical success, pain relief and recurrence, complications, perioperative morbidity, and perioperative mortality. PTGC and MVD initially had similar initial success rates. However, MVD had a higher rate of pain recurrence at the first 2 years follow-up, as well as higher rates of major complications and perioperative morbidity. Meanwhile, PTGC had higher rates of facial numbness, dysesthesia and minor complications.

Suppression of central taste transmission by oral capsaicin

Because intraoral capsaicin is reported to reduce the perceived intensity of certain taste qualities, we investigated whether it affects the central processing of gustatory information. The responses of gustatory neurons in the nucleus tractus solitarius (NTS) to tastant stimuli were recorded before and after lingual application of capsaicin in anesthetized rats. Thirty-four NTS units were characterized as responding best to sucrose (0.3 m), NaCl (0.1 m), citric acid (0.03 m), monosodium glutamate (0.2 m), or quinine (0.001 m). During lingual application of 330 microm capsaicin for 7 min, the firing rate increased for five units and decreased for four units; the remainder were unaffected. Immediately after capsaicin, responses to each tastant were in nearly all cases depressed (mean, 61.5% of control), followed by recovery in most cases. NTS tastant-evoked unit responses were unaffected by lingual application of vehicle (5% ethanol). Capsaicin elicited an equivalent reduction (to 64.5%) in tastant-evoked responses of nine additional NTS units recorded in rats with bilateral trigeminal ganglionectomy, arguing against a trigeminally mediated central effect. Furthermore, capsaicin elicited a puncate pattern of plasma extravasation in the tongue that matched the distribution of fungiform papillae. These results support a peripheral site of capsaicin suppression of taste possibly via direct or indirect effects on taste transduction or taste receptor cell excitability. The depressant effect of capsaicin on gustatory transmission might underlie its ability to reduce the perceived intensity of some taste qualities.

Evaluation of surgical procedures for trigeminal neuralgia

Trigeminal neuralgia is a type of facial pain that is difficult to treat. The pain can be excruciating and debilitating. The wide range of treatments currently used for trigeminal neuralgia is ample evidence that there is no simple answer to how it should be managed. This review will evaluate the current surgical procedures used for the treatment of trigeminal neuralgia. A critical analysis of the evidence-based studies to date was done to evaluate and compare the efficacy of the different surgical procedures. Arguments for and against the use of surgery for trigeminal neuralgia are presented. In addition, the surgical procedures were compared with other treatments for trigeminal neuralgia.

Chronic granulomatous neuritis in idiopathic trigeminal sensory neuropathy. Report of two cases

Idiopathic trigeminal sensory neuropathy is a clinically benign disorder in which the main feature is facial numbness limited to the territory of one or more divisions of the trigeminal nerve; the disorder persists for a few weeks to several years. and no underlying disease can be identified. Magnetic resonance (MR) imaging findings are occasionally consistent with a small trigeminal neuroma of the left gasserian ganglion associated with idiopathic trigeminal sensory neuropathy. The authors report on two patients who were treated using a skull base approach in which the gasserian ganglion was exposed and the lesion was removed. The pathological diagnosis was chronic granulomatous neuritis. The authors conclude that, in patients with MR findings suggestive of a small trigeminal neuroma, benign idiopathic trigeminal sensory neuropathy should also be considered in the differential diagnosis. A conservative approach featuring sequential MR imaging studies may avoid an unnecessary surgical exploration.

Percutaneous trigeminal ganglion compression for the treatment of trigeminal neuralgia: report of two cases

Percutaneous trigeminal ganglion compression for the relief of trigeminal neuralgia is a technically simple, non-painful procedure, carried out under brief general anesthesia. The patients could tolerate well during the treatment. The operation successful rate is high, and the procedure can be repeated at the next day if the symptom was not relieved. The procedure, in the present, is the first choice for those trigeminal neuralgia patients who are poor medical risks, those who are above the age of 65, those with demyelinating disease, and those who are unwilling to accept the increased risk of a posterior fossa craniectomy. We have successfully performed this procedure for two recurrent trigeminal neuralgia patients without any surgical complication. We propose this surgical treatment algorithm for trigeminal neuralgia patients who are not able to tolerate the medical treatment.