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Objective: Before commonly used targets such as the Retrogasserian Zone (RGZ) and the Root Entry Zone (REZ) were adopted for the radiosurgical treatment of trigeminal neuralgia (TN), a more anterior target involving the Gasserian ganglion was used. Thanks to advancements in imaging technology, it is now possible to identify and target separate nerve divisions in Meckel's Cave as desired. Although this approach has been mentioned previously, no clinical study has investigated it until now. This study aims to fill this gap in the literature., Methods: Trigeminal neuralgia patients who received radiosurgical treatment between February 2019 and June 2022 in a single centre were included in the study. Pain relief, medication dependency and side effect profiles of the investigated anterior selective target (AST) were compared to those of the classical targets at 1 week, 1-3-6 months, and 1 year., Results: A total of 66 patients were included in the study. Effectiveness, safety and application convenience parameters were compared between; the REZ (n = 21), RGZ (n = 20) and AST (n = 25) groups. All groups showed significant improvement in pain with similar results to each other. AST treatments were performed in significantly shorter beam-on-times and with significantly lower brainstem doses., Conclusions: The investigated AST showed comparable results to the classical targets without any indication of superiority or inferiority in terms of efficacy and safety in this preliminary investigation. As no blocks were needed to protect the brainstem with this method, it can be used for select patients as needed and could even be investigated in larger studies as an alternative approach., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: Percutaneous rhizotomy of the Gasserian ganglion is a well-established intervention for patients suffering from refractory trigeminal pain, not amenable to pharmacological management or microvascular decompression. Traditionally conducted under fluoroscopic guidance using Hartel's technique, this study investigates a modified approach employing low-dose CT guidance to achieve maximal procedural precision and safety with the emphasis on minimizing radiation exposure., Methods: A retrospective analysis of patients undergoing percutaneous rhizotomy of the Gasserian ganglion at our institution was undertaken. Procedures were divided into fluoroscopy and CT-guided foramen ovale (FO) cannulation cohorts. Radiation doses were assessed, excluding cases with incomplete data. The study included 32 procedures in the fluoroscopy group and 30 in the CT group., Results: In the CT-guided group, the median effective dose was 0.21 mSv. The median number of CT scans per procedure was 4.5, and the median procedure time was 15 min. Successful FO cannulation was achieved in all 30 procedures (100%). In the fluoroscopy group, the median effective dose was 0.022 mSv, and the median procedure time was 15 min. Cannulation of FO was successful in 31 of 32 procedures (96.9%). The only complications in the CT-guided group were three minor cheek hematomas. Immediate pain relief in the CT-guided group was reported in 25 of 30 procedures (83.3%), 22 of 30 (73.3%) provided relief at one month, and 10 of 18 (55.6%) procedures resulting in pain relief at one month continued to provide relief after two years., Conclusion: Low-dose CT-guided percutaneous rhizotomy conducted in the radiology suite carries negligible radiation exposure for patients and eliminates it for personnel. This method is fast, simple, precise, and carries a very low risk of complications., Competing Interests: Declarations. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the University Hospital Pilsen and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: The degree of cervical extension required during percutaneous balloon compression (PBC) of the Gasserian ganglion for trigeminal neuralgia (TN) varies among patients, but the traditional operating tables often fail to fulfil each patient's individual requirements., Objective: This study aimed to compare the clinical efficacy of an extended operating table to that of a traditional operating table in C-arm-guided PBC of the Gasserian ganglion for TN., Study Design: This is a consecutively prospective comparative study., Setting: Fujian Provincial Hospital., Methods: This study consecutively enrolled patients with TN who were scheduled for PBC of the Gasserian ganglion between February 2020 and February 2023. Some patients who underwent the procedure were placed on an extended operating table, whereas others were placed on a traditional operating table. The primary outcome was the duration of the cervical extension. The secondary outcomes included the duration of patient positioning, operation duration, C-arm radiation exposure, and pressure pain threshold of the bilateral trapezius, levator scapulae, and upper trapezius muscles, as well as the occurrence rate of postoperative complications., Results: A total of 76 patients (mean age of 53.18 ± 2.74 years old, 44 men) were enrolled, with 38 patients using the extended operating table. The baseline characteristics between the extended and traditional operating table groups were comparable (P > 0.05). The duration of the cervical extension was significantly shorter in patients who used an extended operating table than in those who used a traditional operating table (58.77 ± 2.11 vs. 76.49 ± 2.16, P < 0.001). Patients who used an extended operating table exhibited significantly shorter positioning time (3.40 ± 0.45 vs. 10.32 ± 0.66, P < 0.001), operation duration (50.88 ± 2.95 vs. 76.49 ± 2.16, P = 0.020), and C-arm radiation exposure (8.71 ± 1.06 vs. 10.87 ± 1.26, P < 0.001) and significantly higher postoperative 24-hour pressure pain thresholds of the bilateral trapezius muscle (left: 274.39 ± 10.42 vs. 187.05 ± 6.19, P < 0.001; right: 272.89 ± 11.62 vs. 185.42 ± 6.88, P < 0.001), bilateral levator scapulae (left: 357.71 ± 11.37 vs. 245.34 ± 12.87, P < 0.001; right: 353.71 ± 14.14 vs. 245.05 ± 13.20, P < 0.001), and bilateral upper trapezius (left: 253.63 ± 10.91 vs. 163.95 ± 8.44, P < 0.001; right: 255.66 ± 11.99 vs. 165.32 ± 7.93, P < 0.001) compared to those who used a traditional operating table. The occurrence of postoperative adverse events, such as headache, neck pain, back pain, and limb numbness, was significantly lower in the extended operating table group (2.63% vs. 13.79%, P = 0.047) than in the traditional operating table group., Limitations: This is a single-center study with a small, homogeneous sample, limiting the generalizability of findings; the absence of randomization raises concerns about potential bias; long-term follow-up and recurrence rate measurements were lacking., Conclusion: This study found that the extended operating table may be an alternative equipment option for C-arm-guided PBC of the Gasserian ganglion for TN.

Background: Surgical treatment for trigeminal neuralgia includes percutaneous techniques, including balloon compression, first described in 1983 by Mullan and Lichtor (J Neurosurg 59(6):1007-1012, 6)., Method: Here we present a safe and simple navigation-assisted percutaneous technique for balloon compression, which can also be used for glycerol injection., Conclusion: The navigation-assisted percutaneous technique for balloon compression for trigeminal neuralgia is a quick and safe treatment for patients not candidates for microvascular decompression., (© 2024. The Author(s).)

Background: The classic percutaneous balloon compression (PBC) technique is used to complete an operation under the guidance of C-arm radiography under general anesthesia, making communication with patients during the operation impossible. It is not accurate or objective to predict the classic technique's curative effect solely by determining whether the projection of the x-ray lateral image of the filled balloon is pear-shaped., Objectives: This study aimed to upgrade classic PBC to awake computed tomography (CT)-guided PBC technology under conscious local anesthesia and analgesia monitoring., Study Design: Prospective clinical study., Setting: Department of Anesthesiology and Pain Medical Center, Jiaxing, People's Republic of China., Methods: Puncture was designed and guided by CT scanning, and the curative effect was assessed by asking the patients about what they are feeling during the operation., Results: CT can design the puncture path and accurately guide puncture, observe the position and shape of the balloon through 3-dimensional reconstruction during the operation, and judge the curative effect according to the patient's chief concern., Limitations: Local anesthetic analgesia is not perfect, resulting in some patients experiencing pain during surgery., Conclusions: PBC can be completed under conscious local anesthesia and analgesia. Its curative effect and operative end standard can be determined according to the patient's chief concern. Under CT guidance, the puncture path can be designed to complete an accurate puncture and to intuitively understand the position and shape of the balloon.

Based on a personal experience of 4200 surgeries, radiofrequency thermocoagulation is useful lesional treatment for those trigeminal neuralgias (TNs) not amenable to microvascular decompression (idiopathic or secondary TNs). Introduced through the foramen ovale, behind the trigemnial ganglion in the triangular plexus, the needle is navigated by radiology and neurophysiological testing to target the retrogasserian fibers corresponding to the trigger zone. Heating to 55-75 °C can achieve hypoesthesia without anaesthesia dolorosa if properly controlled. Depth of anaesthesia varies dynamically sedation for cannulation and lesioning, and awareness during neurophysiologic navigation. Proper technique ensures long-lasting results in more than 75% of patients., (© 2024. The Author(s).)

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., (© 2023. The Author(s) under exclusive licence to The Journal of NeuroVirology, Inc.)

Background: Trigeminal neuralgia (TN) is the most common excruciating cranial neuralgia in the elderly population. Radiofrequency thermocoagulation (RFT) of the trigeminal ganglion is an alternative treatment for medically intractable patients with TN. RFT cannula tip position is an important issue since it is related to treatment outcome and patient safety., Objectives: The purpose of this study was to evaluate the fluoroscopic position of a cannula tip when a maximal stimulation-induced paresthesia was obtained and the treatment outcome using a Barrow Neurological Institute (BNI) pain scale., Study Design: Retrospective analysis., Setting: An interventional pain management practice in South Korea., Methods: The final cannula tip position obtained under maximal electrical stimulation of the face was analyzed using previously saved fluoroscopic images., Results: The cannula tip was located exactly in the clival line in 10 patients (29.4%) with maxillary division (V2) TN. There were 24 patients of V2 TN (70.5% ) in whom the cannula tip was located below the clival line. Over 50% of cannula tips were located at -11 mm to -15 mm below the clival line in mandibular division (V3) TN. Forty-four patients (83%) who received RFT in the trigeminal ganglion demonstrated BNI I or II., Limitations: The number of patients with V3 TN was smaller than that of V2 TN. Only short-term efficacy was evaluated, but not long-term efficacy or recurrence rate of facial pain., Conclusions: Nearly 70% of patients in V2 TN and all patients in V3 TN, the cannula tip was positioned below the clival line. RFT of the trigeminal ganglion showed a successful treatment outcome with BNI I or II in 83% of patients.

Objective: To estimate long-term efficacy and safety for maxillary trigeminal neuralgia (TN) using radiofrequency thermocoagulation (RFT) targeted on Gasserian ganglion, and to identify the factors which may influence outcomes after procedure., Methods: From 2006 to 2019, 1070 patients underwent RFT for the treatment of medically refractory maxillary TN was included. All patients were followed up for at least 2 years. Outcomes and complications were recorded and analysed. Logistic regression analysis was employed to identify risk factors of long-term pain recurrence. Prognostic value was calculated from receiver-operating characteristic curve (ROC)., Results: Longitudinal analysis was taken place for 97 non-responders (9.1%) with ineffective pain relief, 253 responders (23.6%) with pain recurrence and 720 responders (67.3%) without pain recurrence. The median pain-free survival (PFS) was 112.0 months (95% CI: 107.5, 116.5). The pain-free rates were 89.9% (95% CI: 88.0-91.8%) at 1 year, 83.8% (95% CI: 81.5-86.1%) at 2 years, 75.4% (95% CI: 72.7-78.1%) at 5 years and 70.2% (95% CI: 67.4-73.0%) at 10 years. Atypical facial pain (HR = 5.373, 95% CI: 2.623-11.004, p  < .001), previous facial numbness (HR = 5.224, 95% CI: 3.107-8.784, p  < .001) and poor initial response to medication (HR = 3.185, 95% CI: 2.087-4.860, p  < .001) were independently associated with long-term pain recurrence. Patients with prognostic index (PI) > 0.25 were identified as high-risk for recurrent TN (HR = 5.575, 95% CI: 3.991-7.788, p  < .001). New and worsen facial hypoesthesia was recorded in 77.9% of patients corresponding with BNI score II-IV, and 18.7% reported improved sensation. Severe complication incidence including troublesome dysesthaesia, keratitis and masseter weakness was higher in 80 °C group., Conclusions: Favourable outcomes were achieved in terms of long-term pain relief and complications rate after RFT for maxillary TN. Patients with typical facial pain, normal facial sensation, and good initial response to medications may have favourable long-term outcomes.Key messagesThis is a retrospective analysis of radiofrequency thermocoagulation (RFT) targeted on Gasserian ganglion for the treatment of maxillary trigeminal neuralgia (TN) during long-term follow-up. Recurrence-free survival among a large sample was assessed and risk factors associated with long-term pain recurrence was identified. It has been verified that inadvertent damage of ophthalmic and mandibular division causes ophthalmic and masticatory complications. Therefore, a more precise needle tip position and thermocoagulation using a relatively low temperature was recommended.

Background: Surgical treatments for trigeminal neuralgia may include percutaneous techniques including the balloon compression technique. We present here a simple, effective, and safe adaptation of the historical technique described by Mullan in 1978., Method: Our procedure is performed in a bi-plane neuro-radiology room. During general anesthesia, 14-G needle is guided under radioscopy to foramen ovale. The 3-F embolectomy catheter is then inserted and inflated with contrast for a period of 2 min 15 s., Conclusion: Our technique, performed entirely under bi-plane fluoroscopy, allows a quicker and more precise surgery and avoids errors in guiding the catheter that can result serious injury., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Objectives: Radiofrequency thermocoagulation (RFT) is a type of Gasserian ganglion-level ablative intervention that is used for the treatment of trigeminal neuralgia. Guidance technologies are used to assist in the cannulation of the foramen ovale (FO) or foramen rotundum (FR) target. We conducted a systematic review to assess the value of different guidance technologies for RFT., Methods: We searched PubMed, Embase, the Cochrane database, Web of Science, and PROSPERO for studies published from January 2005 until December 2020. Randomized or nonrandomized comparative studies and nonrandomized studies without internal controls were included. The Cochrane Risk of Bias Tool and the nonrandomized studies of interventions-I tool were used to assess individual study characteristics and overall quality., Results: Our query identified 765 publications, and we were able to analyze 11 studies on patients suffering from trigeminal neuralgia. Only one study involved randomized controlled trials, whereas the others featured nonrandomized designs, predominantly before-and-after comparisons. Most of them were observational studies. A total of 222 participants were included, with a median number (range) of 20 (3-53) participants. The objective response rate (ORR) of the one-puncture success rate of RFT using puncture guidance for trigeminal neuralgia was 92% [95% CI (0.79-1), P < 0.001]. Statistically significant differences were observed in the cannulation and operation times between the guided and manual puncture groups (P < 0.001)., Conclusions: RFT with puncture guidance technology has an absolute advantage in puncturing the foramen ovale or foramen rotundum., (© 2022. The Author(s).)

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., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: Radiofrequency thermocoagulation trigeminal rhizotomy (RT-TR) through the foramen ovale is a minimally invasive treatment for trigeminal neuralgia. Navigation of magnetic resonance imaging (MRI) and CT fusion imaging is a well-established method for cannulation of the Gasserian ganglion. In this study, we use the inline measurements from fusion image to analyze the anatomical parameters between the actual and simulation trajectories and compare the short- and intermediate-term outcomes according to determinable factors., Methods: The study included thirty-six idiopathic neuralgia patients who had undergone RT-TR with MRI and CT fusion image as a primary modality or repeated procedures., Results: Among thirty-six treated patients, the inline length of the trigeminal cistern was longer for the simulated trajectory (8.4 ± 2.4 versus 6.5 ± 2.8 mm; p < 0.05), and the predominant structure at risk extrapolated from the inline trajectory was the brainstem, which signified a more medially directed route, in contrast with the equal weighting of temporal lobe and brainstem for the actual trajectory. The preoperative visual analogue scale (VAS) was 9.3 ± 1.0, which decreased to 2.5 ± 2.6 and 2.9 ± 3.1 at first (mean, 3 months) and second (mean, 14 months) postoperative follow-up, respectively. The postoperative VAS scores at the two follow-ups were not statistically significant without a covariate analysis. After adjustment for covariate risk factors, the second follow-up sustained therapeutic benefit was evident in patients with no prior history of related treatment, an ablation temperature greater than 70 °C, and needle location within or adjacent to the trigeminal cistern., Conclusions: This preliminary study demonstrated that the needle location between cistern and ganglion also plays a significant role in better intermediate-term results., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Objective: Radiofrequency thermocoagulation of Gasserian ganglion brings with it the difficult problem of how to provide adequate acesodyne therapy for patients in order to make the treatment more comfortable. In our study, we assess the safety and efficacy of lidocaine local anesthesia in the treatment of trigeminal neuralgia., Methods: From January, 2017 to December, 2020, 80 patients in our hospital who were suffering from trigeminal neuralgia were treated with radiofrequency thermocoagulation through oval foramen. They were all enrolled in our study and randomly divided into a study group and a placebo group. In the study group an appropriate concentration of lidocaine was given outside and inside of the oval foramen after puncturing in place, while in the placebo group the same dose of normal saline was given in the same way. We then recorded the mean arterial pressure (MAP), heart rate (HR) and visual analogue scale (VAS) at different treatment temperatures., Results: The values of MAP and HR in the study group were generally lower than those in the placebo group, and the difference was statistically significant. Additionally, the two groups showed a significant difference in MAP, HR, and VAS at different treatment temperatures. There were significant differences in MAP and VAS between the study group at the baseline as well as each time point thereafter, and the range of MAP and HR in the study group were lower than those in the placebo group., Conclusion: Reasonable lidocaine local anesthesia can provide analgesic effects and prevent hypertension and arrhythmia during Gasserian ganglion radiofrequency thermocoagulation for the treatment of trigeminal neuralgia., (© 2022. The Author(s).)

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.

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.

Background: Trigeminal neuralgia (TN) is a severe pain condition and the most common facial neuralgia. While microvascular decompression (MVD) presents an excellent treatment in neurovascular compression cases, percutaneous thermocoagulation (PT) of the ganglion Gasseri is an alternative option. This study aimed to evaluate post-operative complication rate and outcome of both treatment strategies related to the patient's age., Methods: The medical records of all patients with the diagnosis of trigeminal neuralgia undergoing an MVD or PT of the ganglion Gasseri (between January 2007 and September 2017) were reviewed to determine the efficacy and the complication rate of both methods in regard to the patient's age., Results: Seventy-nine patients underwent MVD surgery and 39 a PT. The mean age of patients in the MVD group was 61 years and 73 years in the PT group. There were 59 (50%) female patients. Nerve-vessel conflict could be identified in 78 (98.7%) MVD and 17 (43.6%) PT patients on preoperative MRI. Charlson comorbidity index was significantly higher in PT group (2.4 (1.8) versus 3.8 (1.8) p < 0.001). The Barrow pain score (BPS) at the last follow-up demonstrated higher scores after PT (p = 0.007). The complication rate was markedly higher in PT group, mostly due to the facial hypesthesia (84.6% versus 27.8%; p < 0.001). Mean symptom-free survival was significantly shorter in the PT group (9 vs. 26 months, p < 0.001). It remained statistically significant when stratified into age groups: (65 years and older: 9 vs. 18 months, p = 0.001). Duration of symptoms (OR 1.005, 95% CI 1.000-1.010), primary procedure (OR 6.198, 95% CI 2.650-14.496), patient age (OR 1.033, 95% CI 1.002-1.066), and postoperative complication rate (OR 2.777, 95% CI 1.309-5.890) were associated with treatment failure., Conclusion: In this patient series, the MVD is confirmed to be an excellent treatment option independent of patient's age. However, while PT is an effective procedure, time to pain recurrence is shorter, and the favorable outcome (BPS 1 and 2) rate is lower compared to MVD. Hence MVD should be the preferred treatment and PT should remain an alternative in very selected cases when latter is not possible but not in the elderly patient per se.

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.

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.

Objectives: Patients with trigeminal neuralgia who are refractory to medical therapy may choose to undergo Gasserian ganglion percutaneous radiofrequency thermocoagulation. However, in cases where the foramen ovale is difficult to access due to various anatomical anomalies, the typical estimation of the facial entry point is suboptimal., Methods: Three-dimensional computed tomography reconstruction imaging performed before surgery revealed anatomical variations in each of the four adult patient cases that made it more difficult to successfully access the foramen ovale (FO) for percutaneous radiofrequency thermocoagulation. Using measurements collected from preoperative imaging that showed each specific anatomical variation in the FO, researchers marked alternate facial entry points that would allow successful probe placement into the FO and recorded the arc angle data in the stereotactic instrument., Results: Patients were evaluated during follow-up visits ranging from seven to 26 months after surgery and asked to rate postoperative pain using a visual analog scale. These scores decreased from 10 to 3 in all four patients by the third day after the procedure. There were no permanent complications or morbidities from the surgery. One patient experienced mild facial numbness; however, this side effect subsided within three months after surgery. During the follow-up period, no patient reported pain recurrence., Conclusions: The expectation for clinicians approaching trigeminal nerve block using a peri-oral approach should be to expect a great degree of potential variability in terms of both distances from the corner of the mouth and needle angle taken to successfully navigate the anatomy and access the foramen ovale., (© 2018 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

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.

Background: Several techniques have been described for the percutaneous treatment of trigeminal neuralgia; however, each has significant drawbacks. We propose a new technique for percutaneous balloon compression of the trigeminal ganglion and distal trigeminal nerve using electromagnetic (EM) neuronavigation., Methods: The procedure was performed in 17 consecutive patients with trigeminal neuralgia. Patients were then followed up with telephone interview. We also performed a cadaveric validation study to further investigate the accuracy of the technique using dye., Results: Excellent clinical outcomes were achieved with a reduction in the median pain score from 10 out of 10 to 0 out of 10 following the procedure. The cadaveric study also demonstrated a high rate of foramen ovale cannulation., Conclusion: EM-based targeting of the foramen ovale and balloon inflation within Meckel's cave is a quick, reproducible and straightforward technique for the percutaneous treatment of trigeminal neuralgia.

In view of the characteristics of high risk and high accuracy in cranio-maxillofacial surgery, we present a novel surgical robot system that can be used in a variety of surgeries. The surgical robot system can assist surgeons in completing biopsy of skull base lesions, radiofrequency thermocoagulation of the trigeminal ganglion, and radioactive particle implantation of skull base malignant tumors. This paper focuses on modelling and experimental analyses of the robot system based on navigation technology. Firstly, the transformation relationship between the subsystems is realized based on the quaternion and the iterative closest point registration algorithm. The hand-eye coordination model based on optical navigation is established to control the end effector of the robot moving to the target position along the planning path. The closed-loop control method, "kinematics + optics" hybrid motion control method, is presented to improve the positioning accuracy of the system. Secondly, the accuracy of the system model was tested by model experiments. And the feasibility of the closed-loop control method was verified by comparing the positioning accuracy before and after the application of the method. Finally, the skull model experiments were performed to evaluate the function of the surgical robot system. The results validate its feasibility and are consistent with the preoperative surgical planning.

Object: This study describes an experimental rabbit model that allows the reproduction of percutaneous operations that are used in patients with trigeminal neuralgia (TN). Attention was given to an exact anatomical description of the rabbit's middle cranial fossa as well as the establishment of conditions for a successful procedure., Methods: Morphometric measurements were taken from 20 rabbit skulls and CT scans. The anatomy of the trigeminal nerve, as well as its surrounding structures, was assessed by bilateral dissection of 13 New Zealand white rabbits (NWR). An ideal approach of placing a needle through the foramen ovale to reach the TG was sought. Validation of correct placement was realized by fluoroscopy and confirmed by dissection., Results: Precise instructions for successful reproduction of percutaneous procedures in NWR were described. According to morphological measurements, for balloon compression of the trigeminal ganglion (TG) the maximal diameter of an introducing cannula is 1.85 mm. The diameter of an empty balloon catheter should not exceed 1.19 mm, and the length of the inflatable part of the balloon can range up to 4 mm. For thermocoagulation the needle electrodes must not exceed an external diameter of 1.39, mm and the length of the non-insolated tip can range up to 4 mm. Glycerol rhizolysis can be achieved because the trigeminal cistern in the NWR is a closed space that allows a long dwelling time (>10 min) of the contrast agent., Conclusions: An experimental NWR model intended for the reproduction of percutaneous procedures on the TG has been meticulously described. This provides a tool that enables further standardized animal research in the field of surgical treatment of TN.

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., Competing Interests: The authors have no conflicts of interest to disclose.

Background: Tumors of the middle fossa or cavernous sinus (CS), or intraorbital tumors, can penetrate each other through the superior orbital fissure (SOF) or neighboring tissue. These complicated pathologies are often treated with highly invasive surgical procedures. In this article, we demonstrate surgical anatomic dissections of the CS, SOF, orbital apex (OA), and dura mater extending to the periorbita from the middle fossa, by performing an epidural dissection via a lateral orbitotomy approach, and discuss findings that may provide guidance during surgery in these regions., Methods: Lateral orbitotomy was performed on latex-injected cadaver heads by making a 2-cm skin incision lateral to the lateral canthus, drilling the lesser and greater sphenoid wings that form the SOF borders, and removing the bone section between the middle fossa and orbit. Dura mater from the middle fossa to the periorbita was exposed to perform anterior clinoidectomy. Meningeal dura was dissected from the endosteal dura, which forms the lateral wall of the CS, to expose the CS, SOF, and OA for dissections., Results: Changing the orientation of the microscope from posterior to anterior enabled regional control for dissection from the Gasserian ganglion to the OA. Cranial nerves that pass through the CS, SOF, and OA were dissected and exposed. The annular tendon was opened, revealing the oculomotor nerves and its branches, as well as the abducens and nasociliary nerves, which pass through the oculomotor foramen and course within the OA and orbit., Conclusions: This approach causes less tissue damage; provides control of the surgical area in spheno-orbital tumors invading the fissure and foramen by changing the orientation of the microscope toward the orbit, OA, SOF, CS, and middle fossa; and expands the indication criteria for lateral orbitotomy surgery. This approach, therefore, represents an alternative surgical method for excising complicated tumors in these regions.

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., Competing Interests: The authors have no conflicts of interest to disclose.

Objectives: The authors describe a technique that includes a stereotactic approach in the preoperative plan in cases where the foramen ovale is difficult to access for radiofrequency thermocoagulation of the Gasserian ganglion., Methods: The study included 395 patients for whom three-dimensional computed tomographic reconstruction of the skull base, maxilla, and mandible was conducted before surgery. Accessibility of the foramen ovale was defined using numerical data from the three-dimensional computed tomographic reconstruction images. In those patients for whom accessibility of the foramen ovale was considered difficult, the authors used a stereotactic frame to design an individual operative plan. Adjustments of a single point of data,-that is, a change in X axis, Y axis, or an arc angle-were guided by radiographic fluoroscopy images. After verifying successful cannulation and electroneurophysiology, thermocoagulation targets-especially multiple targets recorded as data on the Z axis of the stereotactic approach-were identified and treated., Results: There were 24 patients who met the predetermined criteria for having a difficult-to-access foramen ovales-that is, they had at least two contributing factors and/or involvement of division V1 . Twenty-one of the 24 patients required a single satisfactory puncture; three patients required two to three punctures to successfully access the foramen ovale. There were no permanent complications from the procedure., Conclusions: The authors conclude that this stereotactic approach combined with three-dimensional computed tomographic reconstruction model can improve the accuracy, safety, and efficiency of percutaneous radiofrequency thermocoagulation in patients with trigeminal neuralgia for whom the foramen ovale is difficult to access., (© 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Facial pain is often debilitating and can be characterized by a sharp, stabbing, burning, aching, and dysesthetic sensation. Specifically, trigeminal neuropathic pain (TNP), anesthesia dolorosa, and persistent idiopathic facial pain (PIFP) are difficult diseases to treat, can be quite debilitating and an effective, enduring treatment remains elusive., Methods: We retrospectively reviewed our early experience with stimulation involving the trigeminal and sphenopalatine ganglion stimulation for TNP, anesthesia dolorosa, and PIFP between 2010-2014 to assess the feasibility of implanting at these ganglionic sites. Seven patients received either trigeminal and/or sphenopalatine ganglion stimulation with or without peripheral nerve stimulation, having failed multiple alternative modalities of treatment. The treatments were tailored on the physical location of pain to ensure regional coverage with the stimulation., Results: Fluoroscopy or frameless stereotaxy was utilized to place the sphenopalatine and/or trigeminal ganglion stimulator. All patients were initially trialed before implantation. Trial leads implanted in the pterygopalatine fossa near the sphenopalatine ganglion were implanted via transpterygoid (lateral-medial, infrazygomatic) approach. Trial leads were implanted in the trigeminal ganglion via percutaneous Hartel approach, all of which resulted in masseter contraction. Patients who developed clinically significant pain improvement underwent implantation. The trigeminal ganglion stimulation permanent implants involved placing a grid electrode over Meckel's cave via subtemporal craniotomy, which offered a greater ability to stimulate subdivisions of the trigeminal nerve, without muscular (V3) side effects. Two of the seven overall patients did not respond well to the trial and were not implanted. Five patients reported pain relief with up to 24-month follow-up. Several of the sphenopalatine ganglion stimulation patients had pain relief without any paresthesias. There were no electrode migrations or post-surgical complications., Conclusions: Refractory facial pain may respond positively to ganglionic forms of stimulation. It appears safe and durable to implant electrodes in the pterygopalatine fossa via a lateral transpterygoid approach. Also, implantation of an electrode grid overlying Meckel's cave appears to be a feasible alternative to the Hartel approach. Further investigation is needed to evaluate the usefulness of these approaches for various facial pain conditions.

Purpose: Percutaneous ganglion balloon compression (PBC) is a minimally invasive procedure for treatment of trigeminal neuralgia., Materials and Methods: Twenty-seven (19 female and 8 male) patients, who presented with classical symptoms of trigeminal neuralgia, were included. Age ranged from 34 to 91 years (median 62 years), 33 procedures were performed. Duration of the symptoms ranged from 1 year to 30 years (median 5 years)., Results: After the procedure, pain relief was reported in 25 (93%) patients. In two patients, the pain remained the same. The pain free period ranged from 2 to 74 months (median 15 months). A mean duration of analgesia was longer in patients with ideal pear shape of balloon at the time of the procedure compared to nonideal shape (P = 0.01). No major complications occurred in our group of patients., Conclusions: Percutaneous trigeminal ganglion balloon compression is a safe, simple, and effective method for temporary pain relief in a selective group of trigeminal neuralgia patients.

Aim: Surgical approaches to Meckel's cave (MC) are often technically difficult and sometimes associated with postoperative morbidity. The relationship of surgical landmarks to relevant anatomy is important. Therefore, we attempted to delineate quantitatively their anatomy and the relationships between MC and surrounding structures., Material and Methods: With the aid of a surgical microscope, MC and its contents were studied in 15 formalin-fixed cadaver head specimens. Measurements were made and their relationships were observed., Results: The distance from the zygomatic arch and the lateral end of the petrous ridge to MC was 26.5 and 34.4 mm, respectively. The distance from the arcuate eminence, the facial nerve hiatus, and the foramen spinosum to MC was 16.6, 12.8 and 7.46 mm respectively. The TG lay 5.81 mm posterior to the foramen ovale. The distance from the abducens, trochlear and oculomotor nerves to the trigeminal ganglion was 1.87, 5.53 and 6.57 mm respectively. The distance from the posterior and the anterior walls of the sigmoid sinus to the trigeminal porus was 43.6 and 33.1 mm respectively. The trigeminal porus was on average 7.19 mm from the anterior wall of the internal acoustic meatus., Conclusion: The anatomical landmarks as presented herein regarding MC may be used for a safer skull base approach to the region.

Purpose: To determine the effect of lamellar transection surgery on the nerve fiber density (NFD) and pattern of nerve regeneration in the cornea of thy1-YFP transgenic mice., Methods: Wide-field stereo fluorescence microscopy was used to obtain serial images of nerves in live thy1-YFP mice, which express a fluorescent protein in their axons. NFD (mm/mm(2)) was calculated from maximum intensity projection images as the total length of fibers within the area of the contour in which nerves were traced. Whole-mount confocal microscopy was performed to analyze the arrangement of nerves and the types of regenerating fibers., Results: NFD in normal corneas was 35.3 ± 1.8 mm/mm(2). Stereo fluorescence microscopy revealed the presence of a subbasal hairpin nerve layer and an intrastromal nerve trunk layer. After surgery, regenerative sprouting was observed from transected distal ends of intrastromal nerve trunks. NFD also increased, with this increase being maximal between 4 and 6 weeks after surgery. NFD approximated baseline values at 6 weeks and did not change any further at 8 weeks. Regenerated nerves did not readopt the normal corneal nerve arrangement. A dense interlacing network of regenerated nerves was present in the corneal bed. Branches from this network traversed the flap to innervate the epithelium. Immunofluorescence staining revealed that regenerating fronds contained peptidergic nociceptive fibers (positive for calcitonin gene-related peptide and substance P) and myelinated non-nociceptive fibers (positive for neurofilament 200)., Conclusions: Although corneal NFD recovers to normal levels by 8 weeks after nerve transection, the arrangement of regenerated nerves is abnormal.

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.

Purpose: Puncture of the ganglion Gasseri through the foramen ovale and subsequent thermocoagulation, balloon compression, or glycerin injection is a well-established technique to treat trigeminal neuralgia. However, direct puncture of the foramen is sometimes difficult. Here, the authors present a simple technique of improved biplane fluoroscopic control for insertion of the needle into the foramen ovale., Methods: The authors evaluated an alternative oblique X-ray trajectory for the correct placement of a needle into the foramen ovale on cadaveric skull models. After determination of the ideal X-ray trajectory, 13 subsequent patients suffering from trigeminal neuralgia were subjected to intraforaminal needle placement with application of the alternative X-ray trajectory., Results: An oblique projection with the X-ray tube (mean rotation 20.9° and angulations 28°) aligned coaxially to the inserted needle is proposed. On cadaver skull models, this oblique trajectory appeared to be ideal for visualization of the correct needle position. In the 13 patients, an immediate needle insertion into the foramen ovale was achieved under this direct oblique fluoroscopic control. No complications were observed., Conclusions: Experimentally and clinically, the new projection demonstrated three distinct advantages over the standard submental projection: Firstly, the foramen ovale can be better visualized independent of the patient's position. Secondly, needle correction or insertion can be performed much easier because of the direct fluoroscopic control. Thirdly, the correct needle position in the foramen ovale is more reliably determined than with the submental projection due to projection geometry. Further studies are needed to give evidence that the needle insertion into the foramen ovale is easier achieved with the coaxial projection than with the standard technique.

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.

Background: We performed a comparative study of the retrogasserian zone (RGZ) with the dorsal root entry zone (DREZ) target to determine effective gamma knife radiosurgery (GKRS) technique in patients with medically refractory trigeminal neuralgia (TN)., Methods: We retrospectively reviewed the records of 39 patients with refractory TN undergoing GKRS between April 2005 and October 2008. Until October 2007, DREZ was used as the primary target point. Since November 2007, RGZ has been targeted, located anterior to DREZ. The pain outcome of patient, pain recurrence, and treatment-related complications were evaluated., Findings: Using the Barrow Neurologic Index (BNI) pain score, 15 (93.8%) RGZ and 20 (87.0%) DREZ cases achieved treatment success (BNI pain score I-IIIb) (p = 0.631). Seven (43.8%) RGZ and four (17.4%) DREZ patients reported complete pain relief without medications (BNI pain score I). The time to a response after the GKRS was significantly shorter in the RGZ group (mean 4.1 weeks) than in the DREZ group (mean 6.4 weeks) (p = 0.044). The total complication rate (25.0%) in the RGZ group was similar to the DREZ group (26.1%); however, frequency of bothersome facial numbness and dry eye syndrome was lower in the RGZ group (0%, 0%) compared to the DREZ group (13.1%, 8.7%) (p = 0.255 and 0.503)., Conclusions: The RGZ targeting technique in the GKRS for TN had a better treatment success, with fewer bothersome complications compared to the DREZ target.

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.

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.

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.

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.

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.

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.

In a 25-year-old woman with episodic periorbital-temporal pain who eventually developed a sixth nerve palsy, magnetic resonance imaging revealed a lesion predominantly in the Meckel cave that was found to be a capillary hemangioma arising from the mandibular division of the trigeminal nerve. Hemangiomas of the Meckel cave must be considered in cases of facial pain with a sixth nerve palsy. even if there are no clinical findings of trigeminal neuropathy.

The petrolingual ligament is the posteroinferior attachment of the lateral wall of the cavernous sinus, where the internal carotid artery enters the cavernous sinus. The petrous segment of the internal carotid artery finishes and the cavernous segment begins at the superior margin of this ligament. The ligament is surgically important due to its identification as a landmark for dissection of the internal carotid artery during the approaches to posterolateral intracavernous and extracavernous lesions. It can be well exposed after mobilization of the gasserian ganglion, or after the trigeminal root and ganglion have been split along the junction of V2 and V3 (the transtrigeminal approach). The petrolingual ligament was studied in five cadaveric head specimens from ten sides. The size of the ligament was measured, and its anatomical, clinical and surgical importance is discussed.

The blink reflex was prospectively studied in 28 patients with trigeminal neuralgia, prior-to and following percutaneous glycerol rhizotomy to the Gasserian ganglion. Fifteen patients (54%) had varying degrees of sensory loss in the trigeminal nerve distribution already before glycerol injection. Three more patients developed sensory loss following glycerol injection. Thus following glycerol injection 18 patients had graded sensory loss. Pre-injection the blink reflex showed abnormal R1 wave in 57% patients, while direct and consensual R2 waves were abnormal in 43% and 48%, respectively. Post-injection R1 wave was abnormal in 64% patients. Direct R2 waves were abnormal in 33% patients. Thus clinical findings of sensory loss correlated well with pre-and post-injection blink reflex abnormality. Postoperatively R1 and ipsilateral R2 latencies from the side of the injection deteriorated and consensual R2 latency improved, thus, signifying better function on the contralateral side following relief of pain by glycerol rhizotomy.

A modified lateral subtemporal, transpetrous apex and sub-Gasserian ganglion approach was found to be most suitable for clival chordomas. The approach selection was based on the typical anatomical relationship of chordomas in terms of site of origin, pattern of growth and neural and vascular displacements. The approach was suitable to deal with tumour anterior and lateral to the brain stem, the clival part of the tumour and its sub-cavernous sinus extensions. The carotid artery was under control. The approach had the advantage of being simple and relatively quick and of its familiarity to general neurosurgeons. The tumour could be excised radically and extension of anterior, posterior and inferior exposure was possible.

From 1980 through 1993 a series of 44 patients with trigeminal neurinomas was treated. Five of them were operated on for the remainder of the tumour as they had undergone previous surgery elsewhere, 35 were operated on for the first time, and 4 were not operated on for various reasons. An epidural approach to the neurinomas originating in the branches of the Vth nerve peripherally to the Gasserian ganglion (GG) was used. In the neurinomas originating in the GG or in the root of the Vth nerve, either an epidural-transdural approach or an epidural-transdural-transpetrous approach was used. All tumours operated on using the approach described in this article were completely removed. In 10 patients, the Vth nerve sensory deficits increased in comparison with preoperative deficits; in 9 their state remained unaltered; and in 11 the sensory function of the Vth nerve improved. In those patients who had experienced pre-operative atypical trigeminal pain, the pain disappeared after surgery. There was no additional treatment: radiosurgery, irradiation or chemotherapy. Histopathological examination did not reveal any malignant changes in the tumours in any of the patients. Based on our own experience and on the published data it is believed that the best treatment for trigeminal neurinomas is complete microsurgical removal of the lesion.