Radiofrequency Trigeminal Rhizotomy Research Articles

Angle and Distance Analysis on Percutaneous Trigeminal Radiofrequency Rhizotomy for Trigeminal Neuralgia

Angle and Distance Analysis on Percutaneous Trigeminal Radiofrequency Rhizotomy for Trigeminal Neuralgia

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.

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

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. 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. 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. 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. 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.

Surgical Treatment of Trigeminal Neuralgia Combined with Tumors of the Cerebellopontine Angle

Introduction . Trigeminal neuralgia (TN) develops because of demyelination in the entry zone of the trigeminal nerve root (TNR) into the brainstem, which is accompanied by ectopic and cross-excitation of the nerve impulses with paroxysms of facial pain. One of the causes of TN are tumors of the cerebellopontine angle (CPA), which have a direct or indirect effect on the TNR. The optimal surgical approach in such cases depends on the anatomical relationship between the TNR and the tumor and vascular structures. The aim of the study was to evaluate the relationship between the anatomical variants of the TNR and the outcomes of using various surgical methods to treat TN in CPA tumors. Materials and methods. We performed a retrospective analysis of 52 patients (38 women and 14 men aged 22–82 years) with TN and ipsilateral tumors of the CPA: 29 with apical petrous meningiomas, 11 with epidermoid tumors, 10 with vestibular schwannomas, 1 with haemangioma, and 1 with cavernoma. Results. Six variants of the anatomical relationships of the TNR to CPA tumors and the adjacent vascular structures were identified: where the TNR is completely surrounded by the tumor; where the tumor compresses and displaces the TNR; where the tumor is located inside the TNR; where the tumor, together with the blood vessel, compresses the TNR; where the tumor displaces the TNR towards the vessel; and where the tumor is not in contact with the TNR, but the TNR is compressed by the blood vessel. Displacement and deformation of the TNR by CPA tumors was found in 50 patients, and no direct contact between the TNR nerve fibers and the neoplasm was observed in 2 cases. The neurovascular conflict caused by arterial and venous vessels was identified in 16 subjects. The type of a vascular decompression technique depended on the degree of stretching and deformation of the TNR. Postoperative MRI confirmed the complete removal of CPA tumors in 51 patients, while minor epidermoid residue in the contralateral cerebellopontine angle cistern was found in only one subject. There were no fatalities after surgical interventions, and the postsurgical cranial nerve neuropathies were transient and regressed within 2–3 months. In 15 cases, hypoesthesia developed or worsened in the trigeminal nerve innervation zone, then disappeared within several weeks, and was not accompanied by a recurrence of TN. Facial sensitivity improved in 6 cases, who had not previously undergone any surgical manipulations of the TNR and its peripheral branches. Complete regression of TN in the immediate postoperative period was observed in 51 patients. A percutaneous radiofrequency trigeminal rhizotomy was performed in 1 subject with an epidermoid tumor, to eliminate the intense pain paroxysms that persisted for a week. No recurrent growth of CPA tumors or relapses of TN were observed during the subsequent follow-up period of 2–10 years. Conclusion. TN can be caused by direct compression and deformation of the TNR and brainstem by CPA tumors and vascular structures. A detailed examination of the entire length of the TNR after tumor removal is necessary to evaluate the neurovascular relationships. In cases of vascular compression of the TNR, various methods of microvascular decompression can be used to treat TN.

Foramen ovale cannulation guided by intraoperative computed tomography with magnetic resonance image fusion plays a role in improving the long-term outcome of percutaneous radiofrequency trigeminal rhizotomy

BackgroundPercutaneous radiofrequency trigeminal rhizotomy (RF-TR) is a well-established treatment for patients suffering from trigeminal neuralgia (TN) as a primary modality or for those refractory to medical treatment. However, few existing studies have identified intraoperative parameter or navigation technique that can be used to predict the rates of short-term or long-term pain relief. In this study, we analyzed patient characteristics, intraoperative parameters and technical factors, and postoperative changes in relation to immediate and long-term pain relief.MethodThis study included a total 252 patients in which 340 RF-TR were performed under the guidance of intraoperative computed tomography (iCT) alone or with magnetic resonance image (MRI) and iCT fusion imaging.ResultThe immediate pain relief of RF-TR with iCT alone and iCT with MR image guidance with or without cerebrospinal fluid (CSF) outflow were all above 90.4%. The 2-year pain relief rate of RF-TR using iCT alone and iCT with MR images guidance with or without CSF outflow were 47.8%, 39.8%, 71.7%, and 53.9% respectively. Significant factors for 2-year pain relief were CSF outflow, iCT with MR image fusion, non-recurrent TN, and presence of postoperative facial numbness.ConclusionThis preliminary study demonstrated foramen ovale cannulation under the aid of iCT with MR image guidance could improve 2-year pain relief.

Percutaneous radiofrequency trigeminal rhizotomy for the treatment of idiopathic trigeminal neuralgia: Experience in 106 patients

Percutaneous radiofrequency trigeminal rhizotomy for the treatment of idiopathic trigeminal neuralgia: Experience in 106 patients

Application of MRI and intraoperative CT fusion images with integrated neuronavigation in percutaneous radiofrequency trigeminal rhizotomy.

Percutaneous radiofrequency trigeminal rhizotomy (RF-TR) has been an effective treatment modality for medically refractory trigeminal neuralgia. Our group has established a protocol for this procedure that includes intraoperative computed tomography (iCT) navigation. The depth of the puncture needle in our protocol was based on cadaveric studies, and anatomical localization was mainly by electric stimulation test. The limitation of the invisibility of the trigeminal cistern on CT imaging and bias from the patient's subjective expression during neurophysiologic stimulation might affect the accuracy of the needle tip and the treatment effect.This study aimed to evaluate the feasibility and preliminary results of the application of magnetic resonance imaging (MRI) and iCT fusion imaging in RF-TR. The study included 13 patients who received RF-TR with iCT navigation and with recurrence within 3 years. Repeated RF-TR was performed with real-time guidance by MRI and iCT fusion imaging. A pain-free or partial satisfactory response was reported with 12 patients (92 %). There was a statistically significant difference in the depth of the needle tip before and after application of MRI and iCT fusion imaging. This preliminary study demonstrated that the application of MRI and iCT fusion could help with anatomical localization of the trigeminal cistern intraoperatively. The improvement in neuronavigation provides a choice in the treatment of recurrent or persistent trigeminal neuralgia after previous intervention. Long-term follow-up of the result is necessary to evaluate the benefit in terms of durability of therapeutic efficacy.

MRI-based radiation-free method for navigated percutaneous radiofrequency trigeminal rhizotomy.

BACKGROUND/STUDY AIMS: Percutaneous radiofrequency trigeminal rhizotomy (RTR) is a standardized treatment for trigeminal neuralgia, yet it has been associated with serious complications related to the cannulation of the foramen ovale. Some of these complications, such as carotid injury, are potentially lethal. Neuronavigation was recently proposed as a method to increase the procedure's safety. All of the techniques described so far rely on pre- or intraoperative computed tomography scanning. Here we present a simple method based on magnetic resonance imaging (MRI) (radiation free) used to target the foramen ovale under navigation guidance. We retrospectively analyzed nine patients who had undergone navigated percutaneous RTR based solely on preoperative MRI and compared them with 35 patients who underwent conventional RTR guided by fluoroscopy. We analyzed immediate and late outcome and categorized the results into pain free, > 70% pain reduction, and persistent pain. We also compared groups in terms of the duration of the procedure and the complication rates. Here we describe the navigation method in detail and review the anatomical landmarks for target definition. The duration of the surgical procedure was similar in both groups (32.1 in the standard technique versus 34.5 minutes with navigation; p = 0.5157). There was no significant difference between groups regarding pain reduction at the immediate (p = 1.0) or late follow-up (p = 0.6284) time points. Furthermore, no serious complications were observed in the navigated group. We present a simple radiation-free method for neuronavigation-assisted percutaneous RTR. This method proved to be safe and effective, and it is especially recommended for young, inexperienced neurosurgeons.

Percutaneous Trigeminal Rhizotomy for Facial Pain Secondary to Head and Neck Malignancy

Nearly 80% of patients with head and neck cancers experience facial pain related to their tumor or treatment. The majority obtain pain relief with appropriate medical treatment. Occasionally some remain refractory to all analgesics or cannot tolerate the accompanying side effects. They may benefit from surgical intervention. We report a case of medically intractable facial pain secondary to squamous cell carcinoma of the tongue that was successfully treated with percutaneous trigeminal rhizotomy. Percutaneous trigeminal radiofrequency rhizotomy involves thermoablation of the trigeminal nerve within Meckel's cave by an electrode inserted through the cheek and foramen ovale. Facial pain was successfully controlled postoperatively. Percutaneous trigeminal rhizotomy is a surgical option for managing nociceptive pain secondary to a head and neck malignancy. This technique, last reported in the literature almost 30 years ago, must not be forgotten by the next generation of oncologists, pain specialists, and neurosurgeons.

SU‐E‐J‐58: Lens Exposure During Percutaneous Trigeminal Nerve Radiofrequency Rhizotomy Guided by Computed Tomography with Three‐Dimensional Image Reconstruction

Purpose: The eye lens is one of the most radiosensitive tissues; it is an issue to estimate the lens dose during the percutaneous trigeminal nerve radiofrequency rhizotomy guided by computed tomography. The purpose of this abstract was to prove the CTDI(computed tomography dose index) peripheral (CTDIp) could be provided a reference value for the eye lens dose. Methods: There are two methods for estimate the eye lens dose in this study. The first is CTDIp calculated and second is ImPACT software which is common used in CT dose calculation. We Collected the CTDIv in dose report which create from CT scanner automatically. Ten patients who performed the trigeminal neuralgia underwent computed tomography (CT)‐guided percutaneous radiofrequency trigeminal rhizotomy was included. In order to find out the factor of CTDIv and CTDIp, we measured the CTDIv and CTDIp using ion‐chamber and 16‐cm diameter CTDI dose phantom. On the other hand, we also apply the ImPACT software to estimate the eye lens dose, and compare the two values, CTDIp and the eye lens dose from ImPACT. Results: The factor of CTDIv to CTDIp is 1.02. The average CTDIp in 10 patients is 116.65 mGy, and the average lens dose from ImPACT is 124 mGy. It is only 6% error. Conclusion: CTDIp can be provided a reference value for the eye lens dose. And the CTDIv can display in modern CT scanner in time, the radiologist can monitor the radiation dose during the exam. However,how to reduce the lens dose in this process would be next important issue foe us.

Management of bilateral trigeminal neuralgia with trigeminal radiofrequency rhizotomy: a treatment strategy for the life-long disease

The objective of this study was to evaluate the effectiveness of percutaneous controlled radiofrequency trigeminal rhizotomy (RF-TR) in patients with bilateral trigeminal neuralgia (BTN). Patients were analyzed after RF-TR in terms of outcome, safety and complications. Eighty-nine BTN patients underwent 186 RF-TR procedures. Eighty-seven patients had idiopathic trigeminal neuralgia (ITN) and two patients had multiple sclerosis (2.2%). Fifty-six (62.9%) were women and 33 (37.1%) were men. Ages ranged from 29 to 85 years. Anesthesia was administered at a determined optimal level, allowing patient cooperation for controlled and selective lesioning. The mean follow-up period was 101.71 ± 77.7 months. Familial occurrence was seen in two (2.2%) patients. Synchronized pain was observed in 25 (28.2%) patients. Pain occurrence on the contralateral side was observed with an average duration of 124.7 ± 87.13 months. Fifty-four of the 89 patients underwent 146 RF-TR procedures for both sides and 35 underwent 40 RF-TR procedures for one side. Complete pain relief or partial satisfactory pain relief was achieved on the medically treated side in 35 patients. During follow-up, 36 patients required the second procedure and 7 required the third procedure. Acute pain relief was reported in 86 (96.6%) patients. Early (<6 months) pain recurrence was observed in 11 (12.3%) and late (>6 months) recurrence in 25 (28.0%) patients. Complications included diminished corneal reflex in four (2.1%) patients, keratitis in two (1.1%), masseter dysfunction in four (2.1%), dysesthesia in two (1.1%), and anesthesia dolorosa in one (0.5%). RF-TR is an effective, selective, well-controlled, and effortlessly repeatable procedure for treating BTN, especially in the elderly, in terms of low morbidity and mortality rates and high rate of satisfactory pain relief.

Foramen ovale cannulation guided by intra-operative computed tomography with integrated neuronavigation for the treatment of trigeminal neuralgia

Radiofrequency rhizotomy of the Gasserian ganglion for the treatment of trigeminal neuralgia via percutaneous cannulation of the foramen ovale is facilitated by various localization modalities. In our preliminary study, we described the feasibility of computed tomography (CT) using an integrated neuronavigation system to cannulate the foramen ovale. Analysis was performed on 42 consecutive patients who underwent cannulation of the foramen ovale for radiofrequency trigeminal rhizotomy guided by CT using an integrated neuronavigation system. The reproducibility and safety of the neuronavigation-guided procedure were evaluated. Overall, the average dimension of the foramen ovale was 7.1 (1.5) × 4.7 (1.1) mm, and it was successfully cannulated by neuronavigation guidance in 31 (73.8%) patients with a mean cannulation time of 3.1 (0.7) min and an overall procedure time of 68.2 (16.4) min. The remaining 11 (26.2%) patients required subsequent CT guidance for successful puncture of the foramen ovale. These data demonstrate that neuronavigation-guided cannulation of the foramen ovale can be executed both quickly and safely on an outpatient basis. Additionally, the use of CT with integrated neuronavigation technology provides superior visual-spatial information compared to conventional fluoroscopy, the process of CT scanning, object planning, and neuronavigation-guided intervention can be completed in the same locale, and its application is easy to master and has the potential to enhance procedure tolerability of awake patients.

Incidence, morphology and morphometry of the foramen of Vesalius: complementary study for a safer planning and execution of the trigeminal rhizotomy technique

The foramen of Vesalius (FV) is located in the greater wing of the sphenoid bone between the foramen ovale (FO) and the foramen rotundum in an intracranial view. The FO allows the passage of the mandibular branch of trigeminal nerve, which is the target of the trigeminal radiofrequency rhizotomy. We analyzed its location, morphology, morphometry and interrelation among other foramina. 400 macerated adult human skulls were examined. A digital microscope (Dino-Lite plus) was used to capture images from the FV. A digital caliper was used to perform the measurements of the distance between the FV and other foramina (FO, foramen spinosum and the carotid canal) in an extracranial view of the skull base. In the 400 analyzed skulls, the FV was identified in 135 skulls (33.75%) and absent on both sides in 265 skulls (66.25%). The FV was observed present bilaterally in 15.5% of the skulls. The incidence of unilateral foramen was 18.25% of the skulls of which 7.75% on right side and 10.5% on left side. The diameter of the FV was measured and we found an average value of 0.65 mm, on right side 0.63 mm and on the left side 0.67 mm. We verified that positive correlations were statistically significant among the three analyzed distances. This study intends to offer specific anatomical data with morphological patterns (macroscopic and mesoscopic) to increase the understanding of the FV features as frequency, incidence and important distances among adjacent foramina.

Subarachnoid bleeding into the superior cerebellopontine cistern after radiofrequency trigeminal rhizotomy: case report

Sir, We would like to report an unusual case of a patient suffering from trigeminal neuralgia, who underwent percutaneous radiofrequency trigeminal rhizotomy (RF-TR), and complicated with subarachnoidal bleeding in the superior cerebellopontine cistern. A 68-year-old woman had been suffering from medically intractable trigeminal neuralgia. She had a 6-year history of trigeminal neuralgia at the ophthalmic and maxillary branches of the left trigeminal nerve. Cranial magnetic resonance imaging scans revealed no structural or vascular abnormality. Routine preoperative analyses, including coagulation studies, were normal. The patient underwent RF-TR under intravenously administered sedation and analgesia. The localization was confirmed within the nerve by electrical stimulation at 0.5 V (100 Hz, 0.2 m); and a lesion was made at a temperature of 70°C for 60 s. After the procedure, the patient’s pain resolved completely. However, 12 h after the procedure, sudden onset of severe headache, vomiting and neck stiffness occurred. The initial cranial computed tomography (CT) scan was normal. Lumbar puncture examination revealed bloody cerebrospinal fluid (CSF); the lymphocyte and monocyte proportions were normal. The control cranial CT scan showed subarachnoidal bleeding in the left superior cerebellopontine cistern (Fig. 1). The patient underwent conservative treatment, and neck stiffness and headache improved. She was discharged 7 days after the procedure. Trigeminal RF-TR is an effective and commonly performed procedure for control of medically refractory pain. Surgical procedures, such RF-TR, microvascular decompression, etc, may lead to serious complications. Anesthesia dolorosa, painful dysesthesia, absence of corneal reflex, corneal keratitis, masseter paralysis, septic-aseptic meningitis, cranial nerve palsy (cranial nerves III, IV, VI, VII, and VIII), blindness, carotid puncture, and carotidcavernous fistulae are all potential complications of the RFTR procedure [2]. Thus, all surgeons should be aware of these risks and not consider any of these methods as easy and safe. Meckel’s cave and root entry zone, which are the focus of these intervention methods, are at the same time the areas where multiple anatomic variations and vital structures are located [3]. Meckel’s cave opens through a porus into the cerebellopontine cistern. Meckel’s segment of the trigeminal nerve, which begins at the porus and extends to the trigeminal ganglion, is differentiated from the cavernous segment in the wall of the cavernous sinus. Meckel’s segment is narrower adjacent to the porus and fans out as it approaches the posterior edge of the gasserian ganglion, which is embedded in the dura just anterior to the anterior edge of Meckel’s cave. The superior petrosal sinus extends medially through the upper edge of the porus of Meckel’s cave and above the trigeminal nerve to join the cavernous sinus [1]. Some superior petrosal veins may join the sinus on the medial side of the trigeminal nerve. The SCA A. Savas Department of Neurosurgery, School of Medicine, Ankara University, Ankara, Turkey

Virtual reality imaging technique in percutaneous radiofrequency rhizotomy for intractable trigeminal neuralgia

Trigeminal neuralgia (TN) is the most common facial neuralgia, and is extremely painful. We evaluate the effectiveness of percutaneous controlled radiofrequency trigeminal rhizotomy (RFTR) assisted by a virtual reality (VR) imaging technique for idiopathic TN. A total of 2769 patients with TN underwent RFTR procedures between June 1986 and March 2007, with VR assisted guiding and electrode positioning in 26 patients from January 2006 to March 2007. A laminal basicranial CT scan (2 mm slice, 16 slices/s) was used during RFTR. The three-dimensional (3D) position of the electrode needle tip and the oval foramen can be seen clearly using this VR technique. The position and depth of the needle was adjusted according to the virtual 3D-CT scan. CT scanning was performed repeatedly until the needle tip was situated in the oval foramen. Usually, the tip of the electrode was adjusted once or twice. Acute pain relief was accomplished in the 26 patients who underwent a single RFTR procedure assisted with VR. No recurrence of pain was noted except in one patient after 16 months. There were no permanent complications or mortality. VR-assisted RFTR represents a minimally invasive, low-risk technique with a higher efficacy compared with traditional RFTR.

Intracranial Hemorrhage After Percutaneous Radiofrequency Trigeminal Rhizotomy

Radiofrequency thermocoagulation (RFT) of trigeminal ganglion is a commonly performed percutaneous procedure for the management of trigeminal neuralgia. However, it is not free from potentially life-threatening complications. A case of intracranial hemorrhage following RFT, which was managed conservatively, is reported. The authors suggest that coagulation parameters be normalized and intra-procedural blood pressure controlled while performing this technique. As RFT is carried out as an ambulatory procedure, absence of any intracranial complication must be ascertained clinically before the patient is discharged.

Oculo-motility defects and treated trigeminal neuralgia

Purpose: To report the ocular motility defects associated with the surgical treatment of trigeminal neuralgia. Methods: There were five patients who presented with ocular motility defects after surgical treatment of trigeminal neuralgia. In three patients the method of treatment was microvascular decompression (MVD) of the trigeminal ganglion. Two patients were treated with percutaneous controlled radiofrequency trigeminal rhizotomy (RF-TR). Results: There were four male patients. The mean age was 67.8 ± 9.1 years (median, 73years). In the three patients treated with MVD, two presented with fourth nerve palsy and one presented with sixth nerve palsy. All these patients made a complete recovery between 5 and 8 months. In the two patients treated with RF-TR one patient presented with a third nerve palsy that recovered completely over a 6 month period. The other patient presented with a complete third, fourth, and sixth nerve palsy. At the 7-month follow-up he continues to have a partially recovered third nerve palsy. Conclusions: The surgical treatment for trigeminal neuralgia may result in potentially serious ophthalmic side effects or complications. Ophthalmologists should be aware that ocular motor cranial neuropathies can occur after these procedures and that, although complete recovery is seen in the majority of cases, persisting palsies may also be encountered.

The Clinical Effectiveness and Selectivity of Radiofrequency Trigeminal Rhizotomy Using a 2 mm Active Tip Electrode for the Treatment of Trigeminal Neuralgia

Background: To minimize the side effects of radiofrequency trigeminal rhizotomy by making a more selective minimal lesion for the target division of a trigeminal rootlet, we performed this study to evaluate the effectiveness and the selectivity of radiofrequency trigeminal rhizotomy using a 2 mm active tip electrode as compared to a 5 mm active tip electrode. Methods: The authors evaluated 36 cases, in which radiofrequency thermocoagulation of a trigeminal rootlet was performed using a 2 mm active tip electrode or a 5 mm active tip electrode at for 60 seconds in patients suffering from trigeminal neuralgia. One month after each operation, we assessed the clinical effects, selectivity, and the side effects of these operations. Results: Of the 36 patients, 34 patients experienced loss of tic pain. In terms of effectiveness, no difference was found between the two groups. In terms of selectivity, some superiority was shown by the 2 mm active tip electrode, but this was not statistically significant. Masseter weakness or dysesthesia occurred in six patients who suffered from tic pain in the V3 region, and who were operated upon with a 5 mm active tip electrode. Major complications like anesthesia dolorosa, and corneal anesthesia were absent in any patients. Conclusions: For target specific lesion generation of trigeminal rootlets, single lesion generation using a 2 mm active tip electrode may be as clinically effective as a 5 mm tip and is more selective in use.

Percutaneous Radiofrequency Trigeminal Rhizotomy in a Patient with an Implanted Cardiac Pacemaker

Percutaneous radiofrequency ablation is a frequently used treatment for trigeminal neuralgia. Radiofrequency is another potential source of electromagnetic interference to implanted cardiac pacemakers. Our patient had a permanent pacemaker and underwent the procedure without incident.

Treatment of trigeminal neuralgia associated with multiple sclerosis

The incidence of trigeminal neuralgia (TN) in patients with multiple sclerosis is higher than in the general population. If pharmacologic therapy fails, invasive procedures in the gasserian ganglion are usually offered. Microvascular decompression is not routinely performed. The authors report a patient with persistent TN after repetitive trigeminal radiofrequency rhizotomy and finally successful microvascular decompression after demonstration of neurovascular compression with high-resolution MRI.