Stereotactic radiosurgery for primary trigeminal neuralgia: state of the evidence and recommendations for future reports

Outcome Comparison of Drug-Resistant Trigeminal Neuralgia Surgical Treatments-An Umbrella Review of Meta-Analyses and Systematic Reviews

Medical treatment for trigeminal neuralgia (TN) is not always a feasible option due to a lack of full response or adverse effects. Open surgery or percutaneous procedures are advocated in these cases. Several articles have compared the results among different techniques. Nevertheless, the findings of these studies are heterogeneous. Umbrella reviews are studies sitting at the peak of the evidence pyramid. With this umbrella review, we provided a systematic review of the outcomes of the surgical procedures used for TN treatment. Only systematic reviews and meta-analyses were included following the PRISMA guidelines. Ten articles were enrolled for qualitative and quantitative assessment. Level of evidence was quantified using a specific tool (AMSTAR-2). Results were heterogenous in terms of outcome and measurements. Microvascular decompression (MVD) appeared to be the most effective procedure both in the short-term (pain relief in 85-96.6% of cases) and long-term follow-up (pain relief in 64-79% of cases), although showed the highest rate of complications. The results of percutaneous techniques were similar but radiosurgery showed the highest variation in term of pain relief and a higher rate of delayed responses. The use of the AMSTAR-2 tool to quantify the evidence level scored three studies as critically low and seven studies as low-level, revealing a lack of good quality studies on this topic. Our umbrella review evidenced the need of well-designed comparative studies and the utilization of validated scales in order to provide more homogenous data for pooled-analyses and meta-analyses in the field of TN surgical treatment.

High-Dose Frameless Stereotactic Radiosurgery for Trigeminal Neuralgia: A Single-Institution Experience and Systematic Review

OBJECTIVE

Stereotactic radiosurgery is an effective treatment option for trigeminal neuralgia (TN), with frameless stereotactic radiosurgery (fSRS) allowing for a less invasive experience. A single-institutional series and systematic review of the literature were performed for cases of TN treated with fSRS.

METHODS

Patients at our institution with TN that were treated with fSRS from the years 2012-2021 were included. Similarly, multiple databases were searched for studies regarding TN treated with fSRS where patient-level data was included from 2004-2020. Pain levels, via the Barrow Neurological Institute (BNI) scale, before and after treatment were analyzed. Pooled analysis was performed to compare treatment outcomes between studies using CyberKnife and LINAC modalities.

RESULTS

Twenty-three patients at our institution were treated with LINAC fSRS (median treatment dose: 85 Gy). Most patients had TN refractory to previous procedural treatments. Eight (35%) patients had an excellent posttreatment response (BNI I-II), while 11 (48%) patients had a good result (BNI IIIa/b). Eight patients had recurrence of pain. A total of 30 articles were included in the systematic review, encompassing 1705 patients. At last follow-up, 63.1% (774/1227) of patients endorsed an excellent response, while 16.1% (197/1227) had a good response, and 22.5% (215/957) of patients had recurrence. Pain response, facial numbness rates, and pain recurrence rates were not significantly different between CyberKnife and LINAC modalities.

CONCLUSIONS

Frameless SRS for TN appears to be an efficacious noninvasive option for patients with substantial comorbidities, who have failed other treatment methods, although it can be limited by higher recurrence rates.

TREATMENT OPTIONS FOR TRIGEMINAL NEURALGIA

Trigeminal neuralgia causes severe to excruciating pain that often cannot be successfully reduced with current forms of treatment. The International Association for the Study of Pain (IASP) defines trigeminal neuralgia as a sudden, usually unilateral, powerful, short, stabbing, recurrent episode of pain in the distribution of one or more branches of the trigeminal nerve. Trigeminal neuralgia can be caused by vascular compression of the trigeminal nerve or a tumor process. Pressure on the nerve itself causes nerve demyelination, which is the cause of abnormal depolarization, resulting in the development of ectopic impulses. Pain can be provoked by brushing teeth, shaving, eating, cold, heat, etc. After diagnosing trigeminal neuralgia, magnetic resonance imaging should be performed to rule out multiple sclerosis, a tumor process that can secondarily cause trigeminal neuralgia. The drug of choice for treating trigeminal neuralgia is still carbamazepine. If pharmacological treatment fails, invasive surgical microvascular decompression, stereotactic radiation therapy (gamma knife), percutaneous balloon micro compression, percutaneous glycerol rhizolysis, and percutaneous radiofrequency (RF) may be used.

HyperArcTM Dosimetric Validation for Multiple Targets Using Ionization Chamber and RT-100 Polymer Gel

Multiple brain metastases single-isocenter stereotactic radiosurgery (SRS) treatment is increasingly employed in radiotherapy department. Before its use in clinical routine, it is recommended to perform end-to-end tests. In this work, we report the results of five HyperArcTM treatment plans obtained by both ionization chamber (IC) and polymer gel. The end-to-end tests were performed using a water equivalent Mobius Verification PhantomTM (MVP) and a 3D-printed anthropomorphic head phantom PseudoPatient® (PP) (RTsafe P.C., Athens, Greece); 2D and 3D dose distributions were evaluated on the PP phantom using polymer gel (RTsafe). Gels were read by 1.5T magnetic resonance imaging (MRI). Comparison between calculated and measured distributions was performed using gamma index passing rate evaluation by different criteria (5% 2 mm, 3% 2 mm, 5% 1 mm). Mean point dose differences of 1.01% [min −0.77%−max 2.89%] and 0.23% [min 0.01%−max 2.81%] were found in MVP and PP phantoms, respectively. For each target volume, the obtained results in terms of gamma index passing rate show an agreement >95% with 5% 2 mm and 3% 2 mm criteria for both 2D and 3D distributions. The obtained results confirmed that the use of a single isocenter for multiple lesions reduces the treatment time without compromising accuracy, even in the case of target volumes that are quite distant from the isocenter.

Lee J. Gamma Knife radiosurgery for trigeminal neuralgia provides greater pain relief at higher dose rates

In Gamma Knife (GK) radiosurgery, dose rate decreases during the life cycle of its radiation source, extending treatment times. Prolonged treatments influence the amount of sublethal radiation injury that is repaired during exposure, and is associated with decreased biologically-equivalent dose (BED). We assessed the impact of treatment times on clinical outcomes following GK of the trigeminal nerve - a rare clinical model to isolate the effects of treatment times. This is a retrospective analysis of 192 patients with facial pain treated across three source exchanges. All patients were treated to 80 Gy with a single isocenter. Treatment time was analyzed in terms of patient anatomy-specific dose rate, as well as BED calculated from individual patient beam-on times. An outcome tool measuring pain in three distinct domains (pain intensity, interference with general and oro-facial activities of daily living), was administered before and after intervention. Multivariate linear regression was performed with dose rate/BED, brainstem dose, sex, age, diagnosis, and prior intervention as predictors. BED was an independent predictor of the degree of improvement in all three dimensions of pain severity. A decrease in dose rate by 1.5 Gy/min corresponded to 31.8% less improvement in the overall severity of pain. Post-radiosurgery incidence of facial numbness was increased for BEDs in the highest quartile. Treatment time is an independent predictor of pain outcomes, suggesting that prescription dose should be customized to ensure iso-effective treatments, while accounting for the possible increase in adverse effects at the highest BEDs.

Internal Neurolysis for the Treatment of Trigeminal Neuralgia: A Systematic Review

INTRODUCTION

Trigeminal neuralgia (TN) remains a challenging disease with debilitating symptoms and variable efficacy in terms of treatment options. Microvascular decompression (MVD) with internal neurolysis (IN) is an alternative treatment that might benefit patients but has limited understanding. We performed a systematic review of IN for the treatment of TN.

METHODS

Studies from 2000 to 2021 that had assessed IN for TN were aggregated and independently reviewed.

RESULTS

A total of 520 patients in 12 studies were identified, with 384 who had undergone IN (mean age, 53.8 years; range, 46-61.4 years; mean follow-up, 36.5 months). Preoperative symptoms had been present for ∼55.0 months before treatment, and pain was predominantly in V2 and V3 (26.8%), followed by other distributions. Of the patients, 83.7% (range, 72%-93.8%) had had an excellent to good outcome (Barrow Neurological Institute pain scale score [BNI-PS], I-II). The pain outcomes at 1 year were excellent for 58%-78.4%, good or better for 77%-93.75%, and fair or better for 80%-93.75% of the patients. On average, facial numbness after IN was experienced by 96% of the patients. However, at follow-up, facial numbness remained in only 1.75%-10%. Most of the remaining numbness was not significantly distressing to the patients. Subgroup comparisons of IN versus recurrent MVD, IN versus radiofrequency ablation, the effects of IN in the absence of vascular compression, and IN with and without MVD were also evaluated.

CONCLUSIONS

IN represents a promising surgical intervention for TN in the absence of vascular compression and for potential cases of recurrence. Complications were limited in general but require further study.

Stereotactic Radiosurgery for Atrioventricular Node Ablation in Swine: A Study on Efficacy and Dosimetric Evaluation of Organs at Risk

Introduction Stereotactic radiosurgery (SRS) delivered to arrhythmogenic foci within the heart is a promising treatment modality. We dosimetrically evaluated the radiation dose to the organs at risk of four swine that were successfully treated with linear-accelerator-based SRS for atrioventricular (AV) node ablation. Materials and methods Single-chamber pacemakers were implanted in four large white breed swine. Cardiac computed tomography simulation scans were performed to localize the AV node and organs at risk. SRS (35-40 Gy) was delivered to the AV node, and the pigs were followed up with pacemaker interrogations. One-sample t-tests were used to evaluate Dmax of great vessels, esophagus, and chest wall as compared to known normal tissue constraints as per RTOG 0631 and AAPM Task Group 101. Results All pigs had disturbances of AV conduction with progressive transition into complete heart block. Macroscopic and microscopic evaluation showed fibrosis in the AV node but did not reveal any changes in non-nodal cardiac tissue or vessels. The mean Dmax±SD (p-value) of the chest wall (14.7±3.3 (0.02)), esophagus (10.7±1.1 (<0.01)) superior vena cava (3.3±4.1 (<0.01)), right pulmonary artery (16.1±6.4 (<0.01)), right pulmonary vein (15.7± 5 (<0.01)), left pulmonary artery (11.1±1.7 (<0.01)) and left pulmonary vein (14.1±2.6 (<0.01)), and the inferior vena cava (33.68±1.6 (0.026)) were significantly below the normal tissue constraint cutoffs. Mean±SD (p-value) of the ascending aorta (19.4±16.1 (0.12)) was not significantly different than normal tissue constraint cutoffs. One swine model treated at 40 Gy had small area of hotspot in the ascending aorta (40.65 (0.4 cc)). Conclusion We have demonstrated in our swine models that SRS using 35-40 Gy can be done without exceeding known human normal tissue constraints to the chest wall, esophagus, and great vessels.

Percutaneous trigeminal tractotomy for trigeminal neuralgia: Postoperative MRI findings

BACKGROUND AND PURPOSE

Percutaneous trigeminal tractotomy is an ablative procedure that can be used to treat trigeminal neuralgia in patients who have failed prior pharmacologic and surgical treatments. Using perioperative computed tomography (CT) guidance, ablation of the descending spinal trigeminal nucleus and trigeminal tract can be performed precisely to mitigate damage to surrounding structures. These patients are subsequently followed with postoperative imaging and clinical visits to assess long-term pain relief.

METHODS

In this report, we present a series of four patients with trigeminal neuralgia who were had refractory disease after prior medical and surgical interventions. These patients underwent CT-guided percutaneous trigeminal tractotomy for pain relief. The patients underwent postoperative MRI and were followed for up to 6 months for long-term clinical outcomes.

RESULTS

For intraoperative CT, we find that preprocedure lumbar contrast injection enables better visualization of the cord during placement of the ablation probe. On postoperative imaging, we find that all four patients have hyperintense lesions on T2-weighted MRI that correspond with the location of the trigeminal nucleus and tract. Three patients had short-term pain relief, one of which continued to have long-term relief.

CONCLUSION

Intraoperative CT and postoperative MRI serve as useful modalities for confirming localization, evaluating complications, and can be used as a metric for quality control.

Gamma Knife Radiosurgery for Trigeminal Neuralgia: A Comparison of Dose Protocols

Purpose: A variety of treatment plans including an array of prescription doses have been used in radiosurgery treatment of trigeminal neuralgia (TN). However, despite a considerable experience in the radiosurgical treatment of TN, an ideal prescription dose that balances facial dysesthesia risk with pain relief durability has not been determined. Methods and Materials: This retrospective study of patients treated with radiosurgery for typical TN evaluates two treatment doses in relation to outcomes of pain freedom, bothersome facial numbness, and patient satisfaction with treatment. All patients were treated with radiosurgery for intractable and disabling TN. A treatment dose protocol change from 80 to 85 Gy provided an opportunity to compare two prescription doses. The variables evaluated were pain relief, treatment side-effect profile, and patient satisfaction. Results: Typical TN was treated with 80 Gy in 26 patients, and 85 Gy in 37 patients. A new face sensory disturbance was reported after 80 Gy in 16% and after 85 Gy in 27% (p = 0.4). Thirteen failed an 80 Gy dose whereas seven failed an 85 Gy dose. Kaplan–Meier analysis found that at 29 months 50% failed an 80 Gy treatment compared with 79% who had durable pain relief after 85 Gy treatment (p = 0.04). Conclusion: The 85 Gy dose for TN provided a more durable pain relief compared to the 80 Gy one without a significantly elevated occurrence of facial sensory disturbance.

Neuropathic Orofacial Pain

Neuropathic pain of the orofacial region can cause much distress in individuals presenting with this condition. It may be easily mistaken for dental pain, and hence many individuals may undergo unnecessary dental work. Knowledge of the types of neuropathic orofacial pain may assist in timely diagnosis and improvement of a patient's quality of life.

Practical considerations of linear accelerator-based frameless extracranial radiosurgery for treatment of occipital neuralgia for nonsurgical candidates

Occipital neuralgia generally responds to medical or invasive procedures. Repeated invasive procedures generate increasing complications and are often contraindicated. Stereotactic radiosurgery (SRS) has not been reported as a treatment option largely due to the extracranial nature of the target as opposed to the similar, more established trigeminal neuralgia. A dedicated phantom study was conducted to determine the optimum imaging studies, fusion matrices, and treatment planning parameters to target the C2 dorsal root ganglion which forms the occipital nerve. The conditions created from the phantom were applied to a patient with medically and surgically refractory occipital neuralgia. A dose of 80 Gy in one fraction was prescribed to the C2 occipital dorsal root ganglion. The phantom study resulted in a treatment achieved with an average translational magnitude of correction of 1.35 mm with an acceptable tolerance of 0.5 mm and an average rotational magnitude of correction of 0.4° with an acceptable tolerance of 1.0°. For the patient, the spinal cord was 12.0 mm at its closest distance to the isocenter and received a maximum dose of 3.36 Gy, a dose to 0.35 cc of 1.84 Gy, and a dose to 1.2 cc of 0.79 Gy. The brain maximum dose was 2.20 Gy. Treatment time was 59 min for 18, 323 MUs. Imaging was performed prior to each arc delivery resulting in 21 imaging sessions. The average deviation magnitude requiring a positional or rotational correction was 0.96 ± 0.25 mm, 0.8 ± 0.41°, whereas the average deviation magnitude deemed within tolerance was 0.41 ± 0.12 mm, 0.57 ± 0.28°. Dedicated quality assurance of the treatment planning and delivery is necessary for safe and accurate SRS to the cervical spine dorsal root ganglion. With additional prospective study, linear accelerator-based frameless radiosurgery can provide an accurate, noninvasive alternative for treating occipital neuralgia where an invasive procedure is contraindicated.

Delayed Development of Aneurysms Following Gamma Knife Surgery for Trigeminal Neuralgia: Report of 2 Cases

BACKGROUND

Delayed development of intracranial aneurysms is an extremely rare complication of gamma knife surgery (GKS), with only 6 cases been reported to date. There are no reported cases after GKS performed to treat trigeminal neuralgia (TN). Of the 6 aforementioned cases, none referred to the natural history or pathophysiology of GKS-related intracranial aneurysm formation.

CASE DESCRIPTION

We treated 2 patients with subarachnoid hemorrhage (SAH) resulting from rupture of an intracranial aneurysm that developed long after GKS. Case 1 involved a 77-year-old man who had undergone GKS to treat recurrent TN after microvascular decompression surgery. At 13 years after the GSK, he developed SAH from a ruptured left anterior inferior cerebellar artery in close vicinity to the left trigeminal nerve. He died from a premature rupture before intervention could be instituted. Case 2 involved a 72-year-old woman who developed SAH at 9 years after undergoing GKS for TN. A ruptured left superior cerebellar artery aneurysm was treated successfully with endovascular occlusion of the parent artery. She recovered well after the surgery, and was discharged to the rehabilitation hospital with a modified Rankin Scale score of 2.

CONCLUSION

Long-term observations are necessary after GKS performed for TN owing to the possibility of formation of intracranial aneurysms near the irradiated region.

Ultra-extended euthermic pulsed radiofrequency for the treatment of ophthalmic neuralgia: A case report with elaboration of a new technique

BACKGROUND

Pulsed radiofrequency although present for many years has been used little compared to ablative procedures for pain relief. Its use in trigeminal neuralgia is sparse and unreported in the ophthalmic division, where the possibility of sensory loss can lead to high morbidity. We wished to explore the potential of this reportedly safe modality for a prolonged duration in a highly sensitive anatomic neural location, however, in a very secure, structured, and staged manner.

CASE DESCRIPTION

A patient suffering from ophthalmic division (V1) medically uncontrolled neuralgia with a preoperative visual analog scale (VAS) score of 9/10 was subjected to a percutaneous pain relief procedure. The patient was treated with prolonged duration pulsed radiofrequency (PRF) for 40 min, with corneal sensation monitoring under conscious sedation keeping a low voltage (7 V) and tip temperature at 37°C. The patient obtained immediate relief, which was verified on the operation table itself. Postoperative VAS score of 0/10 was recorded. More than 6 months after the procedure, the patient is completely free from neuralgic pain and continues to have a VAS score of 0/10.

CONCLUSION

As opposed to conventional PRF where mostly a tip temperature of 42°C and high voltage have been used for 2 to a maximum of 8 min, PRF with a tip temperature of 37°C and a safe voltage of 7 V over an ultra-extended duration of 40 min can give a more distinct and effective but equally safe result. Although our case verified the safety and efficacy of prolonged duration PRF in sensitive anatomic locations, more studies are warranted for establishing this as a standard line of treatment. The specific use of PRF in ophthalmic division neuralgia in the manner described in our case report has hitherto not been reported in medical literature and will open a new vista in the minimally invasive treatment of this disease.

Utility of CT-cisternogram for radiosurgery in trigeminal neuralgia: A not-to-be forgotten technique

Radiosurgery (RS) is a well-established ablative therapy for trigeminal neuralgia (TGN). Successful RS requires the delivery of an extremely high dose of radiation to a small cisternal portion of the nerve, which lies amidst critical structures. This study describes the utility of CT-cisternogram in RS targeting for TGN. We report on patients with TGN who required CT-cisternogram for target identification for CyberKnife (CK) RS at our institution between September 2010 and April 2015. CT-cisternogram is a well-tolerated procedure that adds useful information to RS planning. Illustrative cases with complex anatomy and MRI artifacts related to postoperative changes and Teflon implant are described. CT-cisternogram is a complementary imaging modality that is useful in some patients, for RS target delineation.

Perineural tumour spread from colon cancer, an unusual cause of trigeminal neuropathy--a case report

Malignant trigeminal neuralgia due to perineural spread along the branches of the trigeminal nerve, is known to commonly occur secondary to squamous cell carcinomas, lymphomas and adenoid cystic carcinomas in the head and neck region. Rarely metastases to the trigeminal nerve have been reported in breast cancer, prostate cancer and colon cancer. To the best of our knowledge trigeminal neuropathy due to skull base metastases and perineural spread along the maxillary (V2) and mandibular (V3) branches of the trigeminal nerve, secondary to colon cancer, has not been previously reported. The diagnosis in our index case was made on magnetic resonance imaging, and patient was treated accordingly by fractionated stereotactic radiotherapy, with subsequent relief of her pain.

Higher dose rate Gamma Knife radiosurgery may provide earlier and longer-lasting pain relief for patients with trigeminal neuralgia

OBJECT

Gamma Knife radiosurgery (GKRS) utilizes cobalt-60 as its radiation source, and thus dose rate varies as the fixed source decays over its half-life of approximately 5.26 years. This natural decay results in increasing treatment times when delivering the same cumulative dose. It is also possible, however, that the biological effective dose may change based on this dose rate even if the total dose is kept constant. Because patients are generally treated in a uniform manner, radiosurgery for trigeminal neuralgia (TN) represents a clinical model whereby biological efficacy can be tested. The authors hypothesized that higher dose rates would result in earlier and more complete pain relief but only if measured with a sensitive pain assessment tool.

METHODS

One hundred thirty-three patients were treated with the Gamma Knife Model 4C unit at a single center by a single neurosurgeon during a single cobalt life cycle from January 2006 to May 2012. All patients were treated with 80 Gy with a single 4-mm isocenter without blocking. Using an output factor of 0.87, dose rates ranged from 1.28 to 2.95 Gy/min. The Brief Pain Inventory (BPI)-Facial was administered before the procedure and at the first follow-up office visit 1 month from the procedure (mean 1.3 months). Phone calls were made to evaluate patients after their procedures as part of a retrospective study. Univariate and multivariate linear regression was performed on several independent variables, including sex, age in deciles, diagnosis, follow-up duration, prior surgery, and dose rate.

RESULTS

In the short-term analysis (mean 1.3 months), patients’ self-reported pain intensity at its worst was significantly correlated with dose rate on multivariate analysis (p = 0.028). Similarly, patients’ self-reported interference with activities of daily living was closely correlated with dose rate on multivariate analysis (p = 0.067). A 1 Gy/min decrease in dose rate resulted in a 17% decrease in pain intensity at its worst and a 22% decrease in pain interference with activities of daily living. In longer-term follow-up (mean 1.9 years), GKRS with higher dose rates (> 2.0 Gy/min; p = 0.007) and older age in deciles (p = 0.012) were associated with a lower likelihood of recurrence of pain.

DISCUSSION

Prior studies investigating the role of dose rate in Gamma Knife radiosurgical ablation for TN have not used validated outcome tools to measure pain preoperatively. Consequently, differences in pain outcomes have been difficult to measure. By administering pain scales both preoperatively as well as postoperatively, the authors have identified statistically significant differences in pain intensity and pain interference with activities of daily living when comparing higher versus lower dose rates. Radiosurgery with a higher dose rate results in more pain relief at the early follow-up evaluation, and it may result in a lower recurrence rate at later follow-up.

Microsurgical Pontine Descending Tractotomy in Cases of Intractable Trigeminal Neuralgia

BACKGROUND

Current treatment strategies in patients with trigeminal neuralgia (TN) include trials of medical therapy and surgical intervention, when necessary. In some patients, pain is not adequately managed with these existing strategies.

OBJECTIVE

To present a novel technique, ventral pontine trigeminal tractotomy via retrosigmoid craniectomy, as an adjunct treatment in TN when there is no significant neurovascular compression.

METHODS

We present a nonrandomized retrospective comparison between 50 patients who lacked clear or impressive arterial neurovascular compression of the trigeminal nerve as judged by preoperative magnetic resonance imaging and intraoperative observations. These patients had intractable TN unresponsive to previous treatment. Trigeminal tractotomy was performed either alone or in conjunction with microvascular decompression. Stereotactic neuronavigation was used during surgery to localize the descending tract via a ventral pontine approach for descending tractotomy.

RESULTS

Follow-up was a mean of 44 months. At first follow-up, 80% of patients experienced complete relief of their pain, and 18% had partial relief. At the most recent follow-up, 74% of patients were considered a successful outcome. Only 1 (2%) patient had no relief after trigeminal tractotomy. Of those with multiple sclerosis-related TN, 87.5% experienced successful relief of pain at their latest follow-up.

CONCLUSION

While patient selection is a significant challenge, this procedure represents an option for patients with TN who have absent or equivocal neurovascular compression, multiple sclerosis-related TN, or recurrent TN.

Update on neuropathic pain treatment for trigeminal neuralgia. The pharmacological and surgical options

Trigeminal neuralgia is a syndrome of unilateral, paroxysmal, stabbing facial pain, originating from the trigeminal nerve. Careful history of typical symptoms is crucial for diagnosis. Most cases are caused by vascular compression of the trigeminal root adjacent to the pons leading to focal demyelination and ephaptic axonal transmission. Brain imaging is required to exclude secondary causes. Many medical and surgical treatments are available. Most patients respond well to pharmacotherapy; carbamazepine and oxcarbazepine are first line therapy, while lamotrigine and baclofen are considered second line treatments. Other drugs such as topiramate, levetiracetam, gabapentin, pregabalin, and botulinum toxin-A are alternative treatments. Surgical options are available if medications are no longer effective or tolerated. Microvascular decompression, gamma knife radiosurgery, and percutaneous rhizotomies are most promising surgical alternatives. This paper reviews the medical and surgical therapeutic options for the treatment of trigeminal neuralgia, based on available evidence and guidelines.

Advances in diagnosis and treatment of trigeminal neuralgia

Various drugs and surgical procedures have been utilized for the treatment of trigeminal neuralgia (TN). Despite numerous available approaches, the results are not completely satisfying. The need for more contemporaneous drugs to control the pain attacks is a common experience. Moreover, a number of patients become drug resistant, needing a surgical procedure to treat the neuralgia. Nonetheless, pain recurrence after one or more surgical operations is also frequently seen. These facts reflect the lack of the precise understanding of the TN pathogenesis. Classically, it has been related to a neurovascular compression at the trigeminal nerve root entry-zone in the prepontine cistern. However, it has been evidenced that in the pain onset and recurrence, various neurophysiological mechanisms other than the neurovascular conflict are involved. Recently, the introduction of new magnetic resonance techniques, such as voxel-based morphometry, diffusion tensor imaging, three-dimensional time-of-flight magnetic resonance angiography, and fluid attenuated inversion recovery sequences, has provided new insight about the TN pathogenesis. Some of these new sequences have also been used to better preoperatively evidence the neurovascular conflict in the surgical planning of microvascular decompression. Moreover, the endoscopy (during microvascular decompression) and the intraoperative computed tomography with integrated neuronavigation (during percutaneous procedures) have been recently introduced in the challenging cases. In the last few years, efforts have been made in order to better define the optimal target when performing the gamma knife radiosurgery. Moreover, some authors have also evidenced that neurostimulation might represent an opportunity in TN refractory to other surgical treatments. The aim of this work was to review the recent literature about the pathogenesis, diagnosis, and medical and surgical treatments, and discuss the significant advances in all these fields.

Long-term efficacy and safety of internal neurolysis for trigeminal neuralgia without neurovascular compression

OBJECT Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). While microvascular decompression (MVD) is the most effective treatment for TN, it is not possible when NVC is not present. Therefore, the authors sought to evaluate the safety, efficacy, and durability of internal neurolysis (IN), or "nerve combing," as a treatment for TN without NVC. METHODS This was a retrospective review of all cases of Type 1 TN involving all patients 18 years of age or older who underwent evaluation (and surgery when appropriate) at Oregon Health & Science University between July 2006 and February 2013. Chart reviews and telephone interviews were conducted to assess patient outcomes. Pain intensity was evaluated with the Barrow Neurological Institute (BNI) Pain Intensity scale, and the Brief Pain Inventory-Facial (BPI-Facial) was used to assess general and face-specific activity. Pain-free survival and durability of successful pain relief (BNI pain scores of 1 or 2) were statistically evaluated with Kaplan-Meier analysis. Prognostic factors were identified and analyzed using Cox proportional hazards regression. RESULTS A total of 177 patients with Type 1 TN were identified. A subgroup of 27 was found to have no NVC on high-resolution MRI/MR angiography or at surgery. These patients were significantly younger than patients with classic Type 1 TN. Long-term follow-up was available for 26 of 27 patients, and 23 responded to the telephone survey. The median follow-up duration was 43.4 months. Immediate postoperative results were comparable to MVD, with 85% of patients pain free and 96% of patients with successful pain relief. At 1 year and 5 years, the rate of pain-free survival was 58% and 47%, respectively. Successful pain relief at those intervals was maintained in 77% and 72% of patients. Almost all patients experienced some degree of numbness or hypesthesia (96%), but in patients with successful pain relief, this numbness did not significantly impact their quality of life. There was 1 patient with a CSF leak and 1 patient with anesthesia dolorosa. Previous treatment for TN was identified as a poor prognostic factor for successful outcome. CONCLUSIONS This is the first report of IN with meaningful outcomes data. This study demonstrated that IN is a safe, effective, and durable treatment for TN in the absence of NVC. Pain-free outcomes with IN appeared to be more durable than radiofrequency gangliolysis, and IN appears to be more effective than stereotactic radiosurgery, 2 alternatives to posterior fossa exploration in cases of TN without NVC. Given the younger age distribution of patients in this group, consideration should be given to performing IN as an initial treatment. Accrual of further outcomes data is warranted.

A review of percutaneous treatments for trigeminal neuralgia

BACKGROUND

Common treatments for trigeminal neuralgia include percutaneous techniques, microvascular decompression, and Gamma Knife radiosurgery. Although microvascular decompression is considered the gold standard for treatment, percutaneous techniques remain an effective option for select patients.

OBJECTIVE

To review the historical development, advantages, and limitations of the most common percutaneous procedures for trigeminal neuralgia: balloon compression (BC), glycerol rhizotomy (GR), and radiofrequency thermocoagulation (RF).

METHODS

Publications reporting clinical outcomes after BC, GR, and RF were reviewed and included. Operative technique was based on the experience of the primary surgeon and senior author.

RESULTS

All 3 percutaneous techniques (BC, GR, and RF) provide effective pain relief but differ in method and specificity of nerve injury. BC selectively injures larger pain fibers while sparing small fibers and does not require an awake, cooperative patient. Pain control rates up to 91% at 6 months and 66% at 3 years have been reported. RF allows somatotopic nerve mapping and selective division lesioning and provides pain relief in up to 97% of patients initially and 58% at 5 years. Multiple treatments improve outcomes but carry significant morbidity risk. GR offers similar pain-free outcomes of 90% at 6 months and 54% at 3 years but with higher complication rates (25% vs. 16%) compared with BC. Advantages of percutaneous techniques include shorter procedure duration, minimal anesthesia risk, and in the case of GR and RF, immediate patient feedback.

CONCLUSION

Percutaneous treatments for trigeminal neuralgia remain safe, simple, and effective for achieving good pain control while minimizing procedural risk.

Trigeminal neuralgia

INTRODUCTION

Trigeminal neuralgia is a sudden, unilateral, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve. Pain occurs in paroxysms, which can last from a few seconds to several minutes. The frequency of the paroxysms ranges from a few to hundreds of attacks a day. Periods of remission can last for months to years, but tend to shorten over time. The condition can impair activities of daily living and lead to depression.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of ongoing treatments in people with trigeminal neuralgia? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found seven studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review, we present information relating to the effectiveness and safety of the following interventions: baclofen; carbamazepine; gabapentin; lamotrigine; oxcarbazepine; microvascular decompression; and destructive neurosurgical techniques (radiofrequency thermocoagulation, glycerol rhizolysis, balloon compression, and stereotactic radiosurgery).

Interventional management of neuropathic pain: NeuPSIG recommendations

Neuropathic pain (NP) is often refractory to pharmacologic and noninterventional treatment. On behalf of the International Association for the Study of Pain Neuropathic Pain Special Interest Group, the authors evaluated systematic reviews, clinical trials, and existing guidelines for the interventional management of NP. Evidence is summarized and presented for neural blockade, spinal cord stimulation (SCS), intrathecal medication, and neurosurgical interventions in patients with the following peripheral and central NP conditions: herpes zoster and postherpetic neuralgia (PHN); painful diabetic and other peripheral neuropathies; spinal cord injury NP; central poststroke pain; radiculopathy and failed back surgery syndrome (FBSS); complex regional pain syndrome (CRPS); and trigeminal neuralgia and neuropathy. Due to the paucity of high-quality clinical trials, no strong recommendations can be made. Four weak recommendations based on the amount and consistency of evidence, including degree of efficacy and safety, are: 1) epidural injections for herpes zoster; 2) steroid injections for radiculopathy; 3) SCS for FBSS; and 4) SCS for CRPS type 1. Based on the available data, we recommend not to use sympathetic blocks for PHN nor radiofrequency lesions for radiculopathy. No other conclusive recommendations can be made due to the poor quality of available data. Whenever possible, these interventions should either be part of randomized clinical trials or documented in pain registries. Priorities for future research include randomized clinical trials, long-term studies, and head-to-head comparisons among different interventional and noninterventional treatments.

American College of Radiology (ACR) and American Society for Radiation Oncology (ASTRO) Practice Guideline for the Performance of Stereotactic Radiosurgery (SRS)

American College of Radiology and American Society for Radiation Oncology Practice Guideline for the Performance of Stereotactic Radiosurgery (SRS). SRS is a safe and efficacious treatment option of a variety of benign and malignant disorders involving intracranial structures and selected extracranial lesions. SRS involves a high dose of ionizing radiation with a high degree of precision and spatial accuracy. A quality SRS program requires a multidisciplinary team involved in the patient management. Organization, appropriate staffing, and careful adherence to detail and to established SRS standards is important to ensure operational efficiency and to improve the likelihood of procedural success. A collaborative effort of the American College of Radiology and American Society for Therapeutic Radiation Oncology has produced a practice guideline for SRS. The guideline defines the qualifications and responsibilities of all the involved personnel, including the radiation oncologist, neurosurgeon, and qualified medical physicist. Quality assurance is essential for safe and accurate delivery of treatment with SRS. Quality assurance issues for the treatment unit, stereotactic accessories, medical imaging, and treatment-planning system are presented and discussed. Adherence to these practice guidelines can be part of ensuring quality and patient safety in a successful SRS program.

Comparative evaluation of surgical procedures for trigeminal neuralgia

Trigeminal neuralgia (TN) is a debilitating ailment. Pharmacotherapy still remains the first line therapy for the management of TN. However, often the patients become refractory to the pharmacotherapy and need surgical interventions. There is a wide array of surgical treatment modalities available for TN and it is important to select the most appropriate surgery for a patient. This review evaluates the various surgical modalities by employing a comparative analysis with respect to patient selection, success rate, complications and cost effectiveness. For the evaluation, a critical review of literature was done with predefined search terms to obtain the details of individual procedures, which were then compared, under similar parameters. The results suggested that microvascular decompression seem to be the most effective treatment in terms of patient satisfaction and long term cost effectiveness. However, if patient factors do not permit, then the peripheral procedures may be employed as a substitute, though they have higher recurrence rate and complications and have relatively lower long term cost effectiveness. The newer modalities like stereotactic radiosurgery and botulinum injections have promising results and further refinement in these procedures will provide additional options for the patients suffering from TN.

Particle therapy for noncancer diseases

Radiation therapy using high-energy charged particles is generally acknowledged as a powerful new technique in cancer treatment. However, particle therapy in oncology is still controversial, specifically because it is unclear whether the putative clinical advantages justify the high additional costs. However, particle therapy can find important applications in the management of noncancer diseases, especially in radiosurgery. Extension to other diseases and targets (both cranial and extracranial) may widen the applications of the technique and decrease the cost/benefit ratio of the accelerator facilities. Future challenges in this field include the use of different particles and energies, motion management in particle body radiotherapy and extension to new targets currently treated by catheter ablation (atrial fibrillation and renal denervation) or stereotactic radiation therapy (trigeminal neuralgia, epilepsy, and macular degeneration). Particle body radiosurgery could be a future key application of accelerator-based particle therapy facilities in 10 years from today.

Long term outcomes of gamma knife radiosurgery for typical trigeminal neuralgia-minimum 5-year follow-up

Objective

Gamma knife radiosurgery (GKRS) is the least invasive surgical option for patients with trigeminal neuralgia (TN). However, the indications and long term outcomes of GKRS are still controversial. Additionally, a series with uniform long-term follow-up data for all patients has been lacking. In the present study, the authors analyzed long-term outcomes in a series of patients with TN who underwent a single GKRS treatment followed by a minimum follow-up of 60 months.

Methods

From 1994 to 2009, 40 consecutive patients with typical, intractable TN received GKRS. Among these, 22 patients were followed for >60 months. The mean maximum radiation dose was 77.1 Gy (65.2-83.6 Gy), and the 4 mm collimator was used to target the radiation to the root entry zone.

Results

The mean age was 61.5 years (25-84 years). The mean follow-up period was 92.2 months (60-144 months). According to the pain intensity scale in the last follow-up, 6 cases were grades I-II (pain-free with or without medication; 27.3%) and 7 cases were grade IV-V (<50% pain relief with medication or no pain relief; 31.8%). There was 1 case (facial dysesthesia) with post-operative complications (4.54%).

Conclusion

The long-term results of GKRS for TN are not as satisfactory as those of microvascular decompression and other conventional modalities, but GKRS is a safe, effective and minimally invasive technique which might be considered a first-line therapy for a limited group of patients for whom a more invasive kind of treatment is unsuitable.

Trigeminal Neuralgia - A Debilitating Facial Pain

Trigeminal neuralgia (TN) is characterised by sudden usually unilateral severe, brief, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve.Diagnosis is largely based on clinical history due to the current lack of objective investigations.MRI can identify those patients who have TN secondary to an underlying pathology such as multiple sclerosis.The first line medical management remains carbamazepine, with oxcarbazepine being the second choice medication.Both percutaneous techniques targeting the Gasserian ganglion and microvascular decompression can be considered effective in the management of TN. Microvascular decompression is considered to provide on average, the longest pain free period post surgery.There are a number of TN associations and support groups which provide a valued service to patients and clinicians.Due to a dearth of high quality studies in many aspects of the condition, TN requires further research to be conducted.

Gamma knife radiosurgery for idiopathic trigeminal neuralgia as primary vs. secondary treatment option

OBJECTIVE

To enable physicians to remain informed of secondary GKR after multiple surgical choices. This study compares gamma knife radiosurgery (GKR) as a first and a second treatment for the management of medically refractory idiopathic trigeminal neuralgia (TN).

METHODS

Between May 1998 and May 2008, a total of 86 patients with idiopathic TN underwent GKR, with 62 patients receiving the treatment as a first therapy (primary GKR group) and 24 patients receiving the treatment as a second procedure (secondary GKR group). The median follow-up time was 76.4 months (range 12-161 months). The mean prescription marginal dose delivered to the involved trigeminal nerve root entry zone was 82.4±6.25Gy for the primary GKR group, and 81.0±4.89Gy for the secondary GKR group. In the secondary group, eleven patients underwent percutaneous radiofrequency rhizotomy (PRFR), seven underwent microvascular decompression (MVD), three underwent percutaneous glycerol rhizotomy and another three underwent GKR as their first treatment. We excluded a typical, multiple sclerosis or secondary trigeminal neuralgia.

RESULTS

No significant differences in radiation dose, time to initial response, recurrence or pain relief were observed between the use of GKR as a primary and a secondary procedure for idiopathic TN. The occurrence of new onset after GKR were the same for the two groups, but overall facial sensory changes was higher in the secondary GKR group.

CONCLUSION

For pain control, GKR can be offered both as a primary and as a secondary procedure, but shows higher overall facial sensory changes in secondary GKR group. The results of our study enable physicians to remain informed of secondary GKR after multiple surgical choices. GKR would be an alternative treatment modality after other surgical treatments including GKR, MVD, PRFR and Glycerol.

Stereotactic radiosurgery using CT cisternography and non-isocentric planning for the treatment of trigeminal neuralgia

OBJECTIVE

Frame-based radiosurgical rhizotomy has been shown in clinical studies to be effective for managing trigeminal neuralgia (TN). To date, however, only a small pilot study has been published for the frameless, image-guided CyberKnife system. We present our preliminary experience with 29 trigeminal neuralgia patients treated with the frameless CyberKnife using X-ray image-guided targeting, a novel CT method for target definition, and non-isocentric planning.

MATERIALS AND METHODS

All 29 patients failed previous medical therapy and 14 had undergone prior surgical procedures. CT iohexal cisternography was used to identify the 6- to 8-mm segment of nerve to be lesioned. The marginal dose ranged from 60 to 70 Gy (median 66.4 Gy) as defined at an average 79th percentile. The corresponding Dmax varied from 71.4 to 86.4 Gy (median 77.91 Gy).

RESULTS

After a median 10-month follow-up, 26 of 29 (90%) patients rated their pain control as excellent and 3 (10%) reported no improvement. Median time to improvement was 6 days. No or only minor progression in numbness was reported by 22 of 29 (76%) patients, 4 of 29 (14%) patients reported worsening, and 3 of 29 (10%) reported the onset of severe ipsilateral facial numbness. Two patients whose target volume inadvertently included the semi-lunar ganglion developed painful dysethesias in the distribution of their numbness.

CONCLUSION

Although the optimal dose and length of nerve to be lesioned are still being refined, this preliminary experience suggests that image-guided robotic radiosurgery can effectively lesion the trigeminal nerve. Further follow-up is needed to determine whether our method has advantages over the more commonly used procedure for radiosurgical trigeminal rhizotomy.

Cranial neuralgias

After a description of the anatomical-functional organization of the human trigeminal system, this chapter discusses the diagnostic and therapeutic options for trigeminal neuralgia (TN). In about 15% of patients who present with the clinical picture of typical TN, this is secondary to a major neurological disease, i.e., benign tumors of the cerebellopontine angle or multiple sclerosis. Some clinical criteria that were used to distinguish between classic and symptomatic TN, such as age at onset, involvement of the ophthalmic division, and responsiveness to medical treatment, are no longer considered reliable. It is recommended that all patients undergo magnetic resonance imaging (MRI) or trigeminal reflex recording. Carbamazepine (CBZ) and oxcarbazepine (OXC) are the first-choice medical treatments. Although other drugs may be effective, these are indicated when the patient cannot reach the therapeutic dosage of CBZ/OXC because of adverse events. Patients unresponsive to CBZ/OXC should be made aware of the available surgical interventions. Surgical procedures (including percutaneous lesions to the ganglion/root, microvascular decompression (MVD) in the posterior fossa, and gamma knife radiosurgery) are extremely efficacious with relatively few complications: each procedure has some advantage and disadvantage with respect to the other. Only MVD is a non-destructive procedure. This chapter also describes management of glossopharyngeal neuralgia, which is often misdiagnosed, and some other chronic pain conditions mediated by the trigeminal system, such as ophthalmic postherpetic neuralgia (PHN).

1. Trigeminal neuralgia

Trigeminal neuralgia is a common cause of facial pain. It has a significant impact on the quality of life and the socioeconomic functioning of the patient. The aim of this review is to provide recommendations for medical management of trigeminal neuralgia based on current evidence. Based upon the analyses of the literature combined with experience in pain management, symptoms, assessment, differential diagnosis, and treatment possibilities of trigeminal neuralgia are described and discussed. Recommendations for pain management are given and are displayed in a clinical practice algorithm. Treatment should be multidisciplinary. Various treatment options and their risks should be discussed with the patient. The first treatment of choice is carbamazepine or oxcarbazepine. In younger patients, the first choice of invasive treatment is probably microvascular decompression. For elderly patients, radiofrequency treatment of Gasserian ganglion is recommended and the technique is described in detail.

Advances in technology for intracranial stereotactic radiosurgery

Stereotactic radiosurgery (SRS) refers to a single radiation treatment delivering a high dose to an intra-cranial target localized in three-dimensions by CT and/or MRI imaging. Traditionally, immobilization of the patient's head has been achieved using a rigid stereotactic head frame as the key step in allowing for accurate dose delivery. SRS has been delivered by both Cobalt-60 (Gamma Knife) and linear accelerator (linac) technologies for many decades. The focus of this review is to highlight recent advances and major innovations in SRS technologies relevant to clinical practice and developments allowing for non-invasive frame SRS.

Trigeminal neuralgia

INTRODUCTION

Trigeminal neuralgia is a sudden, unilateral, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve. Pain occurs in paroxysms which last from a few seconds to 2 minutes. The frequency of the paroxysms ranges from a few to hundreds of attacks a day. Periods of remission can last for months to years, but tend to shorten over time.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments in people with trigeminal neuralgia? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2007 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 14 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: ablative neurosurgical techniques to the Gasserian ganglion, baclofen, carbamazepine, clonazepam, cryotherapy of peripheral nerves, gabapentin, lamotrigine, microvascular decompression, nerve block, oxcarbazepine, peripheral acupuncture, phenytoin, proparacaine eye drops, sodium valproate, stereotactic radiosurgery, tizanidine, and topiramate.

CYBERKNIFE RADIOSURGERY AS A FIRST TREATMENT FOR IDIOPATHIC TRIGEMINAL NEURALGIA

OBJECTIVE

To report the level of effectiveness and safety, in our experience, of CyberKnife (Accuray, Inc., Sunnyvale, CA) robotic radiosurgery as a first-line treatment against pharmacologically refractory trigeminal neuralgia.

METHODS

We treated 33 patients with the frameless CyberKnife system as a monotherapy. The retrogasserian portion of the trigeminal nerve (a length of 4 mm, 2–3 mm anterior to the root entry zone) was targeted. Doses of 55 to 75 Gy were prescribed to the 100% isodose line, according to a dose escalation protocol. The patients were evaluated for the level of pain control, time to pain relief, hypesthesia, and time to pain recurrence.

RESULTS

The median age was 74 years. All but 2 patients (94%) achieved a successful treatment outcome. The follow-up period was 9 to 37 months (mean, 23 months). The Barrow Neurological Institute Pain Intensity Scale (BPS) score before radiosurgery was III in 2 patients (6%), IV in 8 patients (24%), and V in 23 patients (70%). The time to pain relief was 1 to 180 days (median, 30 days). No facial numbness was observed. Only 1 patient developed a transitory dysesthesia of the tongue. After treatment, the BPS score was I, II, or III in 31 patients (97%). Pain recurred in 33% (11 patients) at a mean of 9 months (range, 1–43 months). Three patients with recurrences had low pain control by medication (BPS score, IV), and 1 patient (BPS score, V) needed a radiofrequency lesioning (BPS score, I at 12 months).

CONCLUSION

CyberKnife radiosurgery for trigeminal neuralgia allows pain relief at safe doses and is suggested for pharmacologically refractory trigeminal neuralgia. Higher prescribed doses were not associated with improvement in pain relief or recurrence rate.

A prospective cohort study of microvascular decompression and Gamma Knife surgery in patients with trigeminal neuralgia

OBJECT

The aim of this study was to analyze 1 surgeon's 4-year experience with microvascular decompression ([MVD], 36 patients) and Gamma Knife surgery ([GKS], 44 patients) in 80 consecutive patients with trigeminal neuralgia (TN).

METHODS

The authors conducted a prospective cohort study from March 1999 to December 2003 with an independent clinical assessment of the results and serial patient satisfaction surveys. All patients completed a 2004 patient satisfaction survey (0.5-5 years postoperative), and 70% of surviving patients completed the same survey in 2007 (3.9-8.5 years postoperative). Follow-up was undertaken in 100% of the patients (mean 3.4 +/- 2.14 years, range 0.17-8.5 years).

RESULTS

Respective initial and latest follow-up raw pain-free rates were 100 and 80.6% for MVD and 77.3 and 45.5% for GKS. The median time to the maximal benefit after GKS was 4 weeks (range 1 week-6 months). Respective initial, 2-, and 5-year actuarial pain-free rates were 100, 88, and 80% for MVD and 78, 50, and 33% for GKS (p = 0.0002). The relative risk of losing a pain-free status by 5 years posttreatment was 3.35 for patients in the GKS group compared with the MVD group. Initial and 5-year actuarial rates for >or= 50% pain relief after GKS were 100 and 80%, respectively. The respective rates of permanent mild and severe sensory loss were 5.6 and 0% for patients in the MVD group, as opposed to 6.8 and 2.3% for patients in the GKS group. Anesthesia dolorosa did not occur during the study. Both procedures enjoyed a high degree of early patient satisfaction (95-100%). Microvascular decompression maintained the same rate of patient satisfaction, but satisfaction with GKS decreased to 75% as pain control waned. Twenty-three patients (29%) died of causes unrelated to the TN or the surgical intervention during the follow-up, and their pain status was known at the time of death. Statistically significant intergroup differences for the MVD versus GKS cohorts were age (median 54 years, range 36-70 years vs median 74 years, range 48-92 years, respectively), preoperative symptom duration (median 2.58 years, range 0.33-15 years vs median 7.5, range 0.6-40 years, respectively), and the presence of major comorbidities (2.8 vs 58.3%, respectively).

CONCLUSIONS

In this nonrandomized prospective cohort trial of selected patients with potentially relevant intergroup differences, MVD was significantly superior to GKS in achieving and maintaining a pain-free status in those with TN and provided similar early and superior longer-term patient satisfaction rates compared with those for GKS. The complications of wound cerebrospinal fluid leakage, hearing loss, and persistent diplopia (1 case each in the MVD group) were not seen after GKS.

AAN-EFNS guidelines on trigeminal neuralgia management

Several issues regarding diagnosis, pharmacological treatment, and surgical treatment of trigeminal neuralgia (TN) are still unsettled. The American Academy of Neurology and the European Federation of Neurological Societies launched a joint Task Force to prepare general guidelines for the management of this condition. After systematic review of the literature the Task Force came to a series of evidence-based recommendations. In patients with TN MRI may be considered to identify patients with structural causes. The presence of trigeminal sensory deficits, bilateral involvement, and abnormal trigeminal reflexes should be considered useful to disclose symptomatic TN, whereas younger age of onset, involvement of the first division, unresponsiveness to treatment and abnormal trigeminal evoked potentials are not useful in distinguishing symptomatic from classic TN. Carbamazepine (stronger evidence) or oxcarbazepine (better tolerability) should be offered as first-line treatment for pain control. For patients with TN refractory to medical therapy early surgical therapy may be considered. Gasserian ganglion percutaneous techniques, gamma knife and microvascular decompression may be considered. Microvascular decompression may be considered over other surgical techniques to provide the longest duration of pain freedom. The role of surgery versus pharmacotherapy in the management of TN in patients with multiple sclerosis remains uncertain.

Cyberknife radiosurgery for trigeminal neuralgia treatment: a preliminary multicenter experience

OBJECTIVE

Radiosurgery has gained acceptance as a treatment option for trigeminal neuralgia. We report our preliminary multicenter experience treating trigeminal neuralgia with the CyberKnife (Accuray, Inc., Sunnyvale, CA).

METHODS

A total of 95 patients were treated for idiopathic trigeminal neuralgia between May 2002 and October 2005. Radiosurgical dose and volume parameters were retrospectively analyzed in relation to pain response, complications, and recurrence of symptoms. Optimal treatment parameters were identified for patients who had excellent and sustained pain relief with no complications, including severe or moderate hypesthesia.

RESULTS

Excellent pain relief was initially experienced by 64 out of 95 patients (67%). The median time to pain relief was 14 days (range, 0.3-180 d). Posttreatment numbness occurred in 45 (47%) of the patients treated. Using higher radiation doses and treating longer segments of the nerve led to both better pain relief and a higher incidence of hypesthesia. The presence of posttreatment numbness was predictive of better pain relief. The overall rate of complications was 18%. At the mean follow-up time of 2 years, 47 of the 95 patients (50%) had sustained pain relief, all of whom were completely off pain medications.

CONCLUSION

The results of this study suggest the following optimal radiosurgical treatment parameters for treatment of idiopathic trigeminal neuralgia: a median maximal dose of 78 Gy (range, 70-85.4 Gy) and a median length of the nerve treated of 6 mm (range, 5-12 mm).

Gamma Knife stereotactic radiosurgical treatment of idiopathic trigeminal neuralgia: long-term outcome and complications

OBJECT

Stereotactic radiosurgery (SRS) with the Gamma Knife (GK) is a rapidly emerging surgical modality in the management of medically refractory idiopathic trigeminal neuralgia (TN). The current study examines the long-term outcome in patients with drug-resistant idiopathic TN who underwent GK surgery at the authors' institution.

METHODS

One hundred and six consecutive patients (38 men and 68 women) with proven medically refractory idiopathic TN were included in this retrospective study. Their ages were 41-82 years (mean 72.3 years). All patients underwent SRS with prescribed maximal radiation doses ranging from 70 to 85 Gy. Isocenters 1-3 were used and plugging was used selectively. The follow-up period was 12-72 months (mean 34.3 months). The patients were divided into 2 groups according to their history of previous surgery.

RESULTS

The initial response rate in patients with no history of previous surgery was 92.9%; in those who had undergone previous surgery, the initial response rate was 85.7%. At the end of the 1st posttreatment year, an excellent outcome was achieved in 82.5% of patients who had not had previous surgery, and in 69.4% of those who had. The respective outcome rates for the 2nd posttreatment year were 78 and 63.5%, respectively. The most common complication was the development of persistent paresthesia, which occurred in 15.8% of patients with no previous surgery and 16.3% of those with previous surgery.

CONCLUSIONS

Stereotactic radiosurgery with the GK is a safe and effective treatment option for patients with medically refractory idiopathic TN.