Frameless Image-Guided Radiosurgery for Initial Treatment of Typical Trigeminal Neuralgia

doi:10.1016/j.wneu.2010.07.001

World Neurosurgery

Volume 74, Issues 4–5, October–November 2010, Pages 538-543

https://doi.org/10.1016/j.wneu.2010.07.001 Get rights and content

Objective

To review retrospectively initial experience at a single institution using frameless image-guided radiosurgery (IGRS) for trigeminal neuralgia employing the Novalis linear accelerator (LINAC) with ExacTrac robotic patient positioning device.

Methods

Over an 18-month period, 44 patients (27 women and 17 men; median age 65 years) were treated with frameless IGRS for typical trigeminal neuralgia (14 cases involved left-sided pain and 30 cases involved right-sided pain), responsive to anticonvulsant medications, with Barrow Neurological Institute Pain Scale (BNI-PS) scores of 4 or 5. All cases were initial radiosurgery treatments with an isocenter dose of 90 Gy delivered via a 4-mm circular collimator forming a spheroid dose envelope. Intrafraction positioning data were collected for all patients. The median follow-up was 15 months.

Results

Overall intrafraction positioning error was 0.49 mm ± 0.44. After treatment, 40 patients achieved a BNI-PS score of IIIb or better; 19 patients achieved a BNI-PS score of I. The median time to pain relief was 4 weeks. Overall, new hypoesthesia was seen in five patients. No other complications were seen.

Conclusions

Use of frameless IGRS methods for treatment of trigeminal neuralgia showed results similar to the authors' prior experience with frame-based treatment methods. IGRS using frameless methods is a suitable treatment method for patients with trigeminal neuralgia and may be applicable to other functional indications.

Introduction

Leksell (11) introduced the concept of stereotactic radiosurgery treatment for trigeminal neuralgia in the early 1950s. Radiosurgery was not a frequently used treatment modality, however, until the late 1980s. At that time, advances in imaging and computer-aided dose planning made possible the use of this technique in regular clinical practice. Stereotactic radiosurgery has since become an important alternative for treatment of trigeminal neuralgia. The results of treatment using frame-based instrumentation including Gamma Knife and linear accelerator (LINAC) devices have been well described and have been similar between different reporting centers (3, 15, 20, 21, 27, 29). Radiosurgery can result in satisfactory relief of pain for most patients with minimal procedural risk.

Over the last decade, frameless radiosurgery methods have been an area of significant interest (2, 4, 25, 31, 33). Frameless techniques allow for a true noninvasive procedure without the need for anesthetics and sterile processing. Frameless methods allow for more flexible work flow because the imaging, planning, and treatment segments of the procedure can be performed in separate sessions. Frameless methods rely on intraprocedure imaging to track the site of treatment and correct for any positioning errors automatically. Phantom studies have shown that frameless image-guided positioning can potentially result in overall geometric precision similar to what can be obtained with frame-based methods (2, 31). Few studies have investigated clinical outcomes for frameless radiosurgery methods for functional targets, however (6, 24, 30).

We present retrospectively obtained clinical outcomes and patient positioning data regarding frameless image-guided radiosurgery (IGRS) for initial treatment of typical trigeminal neuralgia using the BrainLAB Novalis ExacTrac system (BrainLAB AG, Feldkirchen, Germany). Our dose planning method is identical to our previous reports with frame-based LINAC and similar to the dose method for most centers using gamma unit radiosurgery (3).

Section snippets

Patient Selection

Over an 18-month period, frameless IGRS was performed in 44 patients for initial treatment of typical trigeminal neuralgia. All patients had primarily paroxysmal electrical or shooting pain with past responsiveness to anticonvulsant-class pain medications (e.g. carbamazepine, phenytoin, gabapentin). Patients with multiple sclerosis were not included in this study. All patients were assessed before treatment using the Barrow Neurological Institute Pain Scale (BNI-PS) score and were self-assessed

Results

Over an 18-month period, 44 patients (27 women and 17 men) underwent frameless IGRS as the first treatment of trigeminal neuralgia. The median age was 65 years (range 35.2–90.5 years). Of patients, 14 were treated for left-sided trigeminal neuralgia, and 30 were treated for right-sided disease. The median time from initial diagnosis to treatment was 5.2 years (range 0.4–28 years). Of patients, 7 had pain in V2 only; 12, in V3 only; 9, in V1-V2; 6, in V1-V2-V3; and 10, in V2-V3.

Radiosurgery for Trigeminal Neuralgia

Typical trigeminal neuralgia can be treated by many effective interventions. These interventions can be categorized into destructive and nondestructive procedures. The sole nondestructive procedure is microvascular decompression (9), a procedure designed to remedy what is thought to be the most common cause of trigeminal neuralgia: contact between a blood vessel and the trigeminal nerve. Destructive procedures include various percutaneous rhizotomy procedures and stereotactic radiosurgery. In

Conclusions

Ultimately, regardless of the technology used, the critical issue is likelihood of pain improvement after treatment. Our data suggest that the outcomes are similar to past reports seen with frame-based radiosurgery using LINAC or Gamma Knife radiosurgery. Further study is needed, preferably in a prospective randomized fashion, to compare directly results using frame and frame-based techniques for trigeminal radiosurgery treatments.

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Cited by (25)

Frameless trigeminal neuralgia radiosurgery with a dedicated linear accelerator: From equipment commissioning to initial clinical results
2024, Cancer/Radiotherapie
La radiochirurgie pour le traitement de la névralgie du trijumeau délivre une très forte dose en une seule séance, sur quelques millimètres, au niveau d’un isocentre unique placé le long du nerf. Nous présentons ici les différentes étapes qui ont été réalisées pour valider des petits faisceaux par collimateurs coniques, et rapportons les résultats cliniques des premiers patients pris en charge sur Novalis Tx® sans cadre invasif.
Nous avons d’abord été évalué l’exactitude géométrique des collimateurs coniques de 4 et 6 mm à l’aide de tests de Winston-Lutz ; puis l’acquisition des données dosimétriques a été réalisée grâce à des détecteurs de haute résolution spatiale (microdiamant PTW 60019 et une diode E PTW 60017). Les facteurs correctifs du rapport TRS n^o 483 ont été appliqués pour le calcul des facteurs d’ouverture du collimateur. Ces données dosimétriques ont ensuite été comparées avec les données implémentées dans le système de planification de traitement iPlan®. Puis des tests end-to-end ont permis de contrôler l’ensemble du processus de traitement à l’aide d’un fantôme anthropomorphique stereotactic end-to-end verification. Entre 2020 et 2022, 18 patients ont été traités pour névralgie trigéminale réfractaire sur Novalis Tx® sans cadre invasif avec repositionnement par Exactrac®. Dix-sept patients ont été évalués (un a été perdu de vue) à l’aide du score du Barrow Neurological Institute pour l’évaluation de la douleur, et par IRM avec un suivi médian de 12 mois.
Les critères de qualité d’exactitude géométrique et dosimétriques ont été atteints pour le cône de 6 mm mais pas pour le cône de 4 mm. Tous les patients ont été traités avec un cône de 6 mm avec une dose de 90 Gy prescrite à l’isocentre ciblée au niveau de la root entry zone. Le contrôle initial de la douleur a été obtenu chez 70,5 % de nos patients, et 53 % ont conservé ce contrôle avec un suivi médian de 12 mois. Toutes les récidives sont survenues dans un délai de 3 à 6 mois après la radiochirurgie. Aucune toxicité n’a été observée sur le tronc cérébral. Trois patients ont eu une hypoesthésie faciale non invalidante.
Le traitement des névralgies trigéminales sur accélérateur linéaire dédié est un traitement de haute technicité dont l’exactitude et la sécurité est primordiale. Les mesures physiques ont permis la mise en service de la technique avec un cône de 6 mm. Nos premiers résultats cliniques sont conformes aux données de la littérature.
Radiosurgery for the treatment of trigeminal neuralgia delivers a very high dose in a single fraction, over a few millimeters, at a single isocenter placed along the nerve. We present here the different steps that have been performed to validate small beams by conical collimators, and report the clinical results of the first patients treated on Novalis Tx®, frameless.
First, the geometric accuracy of 4 and 6 mm conical collimators was evaluated using Winston-Lutz tests; then dosimetric data acquisition was performed using high spatial resolution detectors (PTW 60019 microdiamond and a PTW 60017 E-diode). The corrective factors of the TRS 483 report were applied to calculate the collimator aperture factors. These dosimetric data were then compared with the data implemented in the iPlan® treatment planning system. Then end-to-end tests were performed to control the entire treatment process using an anthropomorphic phantom “STEEV”. Between 2020 and 2022, 18 patients were treated for refractory trigeminal neuralgia on Novalis Tx®, frameless, with Exactrac® repositioning. A total of 17 patients were evaluated (one was lost to follow-up) using the BNI score for pain assessment and MRI with a median follow-up of 12 months.
The quality criteria of geometric and dosimetric accuracy were met for the 6-mm cone but not for the 4-mm cone. All patients were treated with a 6-mm cone with a dose of 90 Gy prescribed at the isocenter at the root entry zone. Initial pain control was obtained in 70.5% of our patients, and 53% maintained pain control with a median follow-up of 12 months. All recurrences occurred within 3 to 6 months after radiosurgery. No brainstem toxicity was observed. Six patients had non-disabling facial hypoesthesia, half of whom already had pretreatment hypoesthesia.
The treatment of trigeminal neuralgia on a dedicated linear accelerator is a highly technical treatment whose accuracy and safety are paramount. The physical measurements allowed the commissioning of the technique with a 6 mm cone. Our first clinical results are in accordance with the literature.
High-Dose Frameless Stereotactic Radiosurgery for Trigeminal Neuralgia: A Single-Institution Experience and Systematic Review
2022, World Neurosurgery
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.
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.
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.
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 Outcomes in Trigeminal Neuralgia–A Systematic Review of Domains, Dimensions and Measures
2020, World Neurosurgery: X
Citation Excerpt :
The IMMPACT Outcome Domains are as follows: 1) Pain; 2) Physical functioning; 3) Emotional functioning; 4) Participant ratings of global improvement/satisfaction; 5) Symptoms and adverse events; and 6) Participant disposition. With the exception of 8 papers, all studies used pain as an outcome domain (Figure 2 and Table 1).13-459 Symptoms and adverse events also were described in a high number of papers (n = 386); however, the impact of treatment on physical and emotional functioning was significantly less evaluated, in 46 and 17 studies, respectively (Tables 2 and 3).460-464
Trigeminal neuralgia (TN) is a painful disorder characterized by sudden electric shock–like pain. It is a rare condition for which multiple treatments are available, including medical and surgical. The best treatment option is yet to be defined, and this is related to the lack of definition in the treatment outcomes and outcome measures. The aim of this systematic review was to summarize all the outcomes and outcomes measures that have been published to date and highlight variability in their use.
We have conducted a literature search using a wide range of databases (1946–2019 for medical and 2008–2019 for surgical treatment), for all intervention studies in TN. Four hundred and sixty-seven studies were selected for data extraction on TN classification, data collection method, intervention, and treatment outcomes mapped to the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT guidelines).
Most studies collected data on pain (n = 459) and side effects (n = 386) domains; however, very few collected data on the impact of treatment on physical (n = 46) and emotional functioning (n = 17) and on patient satisfaction (n = 35). There was high variability on outcome measures used for pain relief (n = 10), pain intensity (n = 9), and frequency of pain episodes (n = 3).
A clear definition of what are the important outcomes for patients with TN is essential. The choice of standardized outcome measures allowing for consistent reporting in TN treatment will allow for comparison of studies and facilitate treatment choice for patients and clinicians thus, improving health outcomes and reducing health care cost.
Meta-Analysis on Safety and Efficacy of Microsurgical and Radiosurgical Treatment of Trigeminal Neuralgia
2017, World Neurosurgery
Classic trigeminal neuralgia is often treated pharmacologically first. However, microvascular decompression (MVD) or radiosurgical treatment (RS) can render medication unnecessary. Objective appraisals of the 2 treatment modalities are scarce.
To compare the evidence regarding safety and efficiency of MVD and RS.
We searched PubMed for studies describing pain control, complications, and recurrences after MVD or RS between 2005 and 2015. Because randomized studies are lacking, we focused the statistical analysis on cohort clinical trials. Differences in outcome after treatment with either MVD or RS were analyzed using t tests and weighted averages. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed.
Fifty-three studies (13,805 patients, in 11 prospective and 42 retrospective studies) were analyzed. Initial success rates were 71.1% for RS and 86.9% for MVD (P < 0.0001). At last follow-up (>5 years after intervention), success rates decreased to 63.8% for RS versus 84% for MVD (P = 0.036). Thirty-six months after the intervention, median percentage of recurrence was 11% for MVD and 25% for RS (P = 0.0015). The length of recurrence-free intervals was similar for MVD and RS (30.45 vs. 30.55 months; P = 0.987).
There was no significant difference between the incidence of hearing loss after MVD and RS (1.51% vs. 0.74%; P = 0.21). Facial dysesthesia was reported more frequently after radiosurgery (2.3% vs. 28.8%; P = 0.02).
MVD is a valid first-line treatment option for young patients free of comorbidities. First-line RS can be advised in patients with a higher surgical risk.
Radiosurgical target distance from the root entry zone in the treatment of trigeminal neuralgia
2017, Practical Radiation Oncology
Citation Excerpt :
Previous studies have established the effectiveness of gamma knife radiosurgery in the treatment of TN.8-12 Radiosurgery using the Novalis linear accelerator, which uses x-rays rather than gamma rays, has also been shown to be effective in the treatment of TN and is becoming increasingly popular.13 Targeting different sites along the path of the trigeminal nerve has been performed in attempts to maximize pain relief.
Stereotactic radiosurgery (SRS) provides a noninvasive treatment modality for patients with medically refractory trigeminal neuralgia. The root entry zone (REZ) has been proposed to be an ideal stereotactic target because it is partially composed of centrally produced myelin, conferring a theoretical increased sensitivity to irradiation as well as increased susceptibility to neurovascular conflict, making it the site in which nociceptive signals likely arise. The aim of this study is to determine if there is a statistically and clinically significant difference in pain relief or facial hypesthesia following SRS based on distance of the stereotactic isocenter from REZ.
Patients undergoing Novalis radiosurgery for the treatment of trigeminal neuralgia with at least 3 months’ follow-up were included in this study. Postoperative outcomes were stratified by Barrow Neurological Institute (BNI) score for pain relief and BNI facial numbness score for facial hypesthesia.
Sixty-seven patients met inclusion criteria and were included in this study. BNI score of I-IIIa was attained in 82% of patients at 3 months and 65% at 1 year following SRS. Distance from isocenter to REZ varied from 0 to 8.6 mm, with a mean of 1.94 ± 1.62 mm. Logistic regression of target-REZ distance against pain relief outcome (patients with score I-IIIa and IIIb-V) was insignificant at 3 months (P = .988), 6 months (P = .925), 9 months (P = .845), and 12 months (P = .547) postoperatively. Furthermore, no significant correlation was found with logistic regression of target-REZ distance with pain relief outcome (patients with score I and score II-IV) (P = .544).
The current analysis suggests that distance from REZ does not correlate with degree of postoperative pain relief or facial hypesthesia; thus, targeting specific regions within the trigeminal nerve in relation to these anatomical characteristics may not afford any advantage from this perspective.
Margin of error for a frameless image guided radiosurgery system: Direct confirmation based on posttreatment MRI scans
2017, Practical Radiation Oncology
Citation Excerpt :
For LINAC-based system there has been no report available in literature showing actual treatment delivery positioning accuracy based on direct measurement of posttreatment patient magnetic resonance imaging (MRI) scan analysis. In this study, the treatment radiation was delivered from a Varian TX LINAC (Varian Medical Systems, Palo Alto, CA) and Brainlab ExacTrac system (BrainLAB, Feldkirchen, Germany) was used for image guidance.16,17,27 We report the results of our radiation treatment delivery positioning accuracy based on direct confirmation from posttreatment MRI scan analyses and present the technical aspects of dosimetry and quality assurance (QA) in treating tremor with frameless radiosurgery.
To report on radiosurgery delivery positioning accuracy in the treatment of tremor patients with frameless image guided radiosurgery using the linear accelerator (LINAC) based ExacTrac system and to describe quality assurance (QA) procedures used.
Between 2010 and 2015, 20 patients underwent radiosurgical thalamotomy targeting the ventral intermediate nucleus for the treatment of severe tremor. The median prescription dose was 140 Gy (range, 120-145 Gy) in a single fraction. The median maximum dose was 156 Gy (range, 136-162 Gy). All treatment planning was performed with the iPlan system using a 4-mm circular cone with multiple arcs. Before each treatment, QA procedures were performed, including the imaging system. As a result of the extremely high dose delivered in a single fraction, a well-defined circular mark developed on the posttreatment magnetic resonance imaging (MRI). Eight of these 20 patients were selected to evaluate treatment localization errors because their circular marks were available in posttreatment MRI. In this study, the localization error is defined as the distance between the center of the intended target and the center of the posttreatment mark.
The mean error of distance was found to be 1.1 mm (range, 0.4-1.5 mm). The mean errors for the left-right, anteroposterior, and superoinferior directions are 0.5 mm, 0.6 mm, and 0.7 mm, respectively.
The result reported in this study includes all tremor patients treated at our institution when their posttreatment MRI data were available for study. It represents a direct confirmation of target positioning accuracy in radiosurgery with a LINAC-based frameless system and its limitations. This level of accuracy is only achievable with an appropriate QA program in place for a LINAC-based frameless radiosurgery system.

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: Conflict of interest statement: The authors and institution have no financial interest in, and have received no support, financial or otherwise, from BrainLAB AG, GE Medical Systems, or their subsidiaries.

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Peer-Review ReportFrameless Image-Guided Radiosurgery for Initial Treatment of Typical Trigeminal Neuralgia

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Patient Selection

Results

Radiosurgery for Trigeminal Neuralgia

Conclusions

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Gamma knife radiosurgery for primary management for trigeminal neuralgia

J Neurosurg

An analysis of the accuracy of the CyberKnife: a robotic frameless stereotactic radiosurgical system

Neurosurgery

Prognostic factors for radiosurgery treatment of trigeminal neuralgia

Neurosurgery

Contemporary methods of radiosurgery treatment with the Novalis linear accelerator system

Neurosurg Focus

Long-term outcomes of Gamma Knife radiosurgery for classic trigeminal neuralgia: implications of treatment and critical review of the literature

J Neurosurg

CyberKnife radiosurgery as a first treatment for idiopathic trigeminal neuralgia

Neurosurgery

Gamma Knife surgery used as primary and repeated treatment for idiopathic trigeminal neuralgia

J Neurosurg

Arterial compression of the trigeminal nerve at the pons in patients with trigeminal neuralgia

J Neurosurg

Gamma knife radiosurgery as the first surgery for trigeminal neuralgia

Stereotact Funct Neurosurg

Peer-Review Report
Frameless Image-Guided Radiosurgery for Initial Treatment of Typical Trigeminal Neuralgia