The clinical application of plugging patterns for the Leksell gamma knife

2002 ◽  
Vol 97 ◽  
pp. 579-581 ◽  
Author(s):  
Paul Vaughan ◽  
Anna Hampshire ◽  
Tracy Soanes ◽  
Andras Kemeny ◽  
Matthias Radatz ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Trigeminal Neuralgia ◽  
Stereotactic Radiosurgery ◽  
Radiation Field ◽  
Gamma Knife ◽  
Clinical Application ◽  
Trigeminal Nerve ◽  
Conformity Index ◽  
Content Type ◽  
Fine Print

Object. In this report the authors explore the use of standardized plugging templates in formulating stereotactic radiosurgery dose plans for the Leksell gamma knife. Methods. Unplugged gamma knife dose plans previously used in the treatment of patients with trigeminal neuralgia (TN) and vestibular schwannoma (VS) were studied. Standardized plugging templates were then superimposed on these plans, and their effects on the conformity index of tumors and the transposition of the radiation field from the brainstem to the cerebrospinal fluid spaces for the trigeminal cases were examined. Conclusions. The standardized plugging templates significantly increased the conformity indices in cases of VS plans and for TN. Plugging significantly reduced the brainstem exposure to radiation while at the same time not altering the length of the trigeminal nerve being treated. Standardized plugging templates may therefore be a useful tool in optimizing dose plans.

Targeting the cranial nerve: microradiosurgery for trigeminal neuralgia with CISS and 3D-Flash MR imaging sequences

2005 ◽  
Vol 102 ◽  
pp. 107-110 ◽  
Author(s):  
Vasilios A. Zerris ◽  
Georg C. Noren ◽  
William A. Shucart ◽  
Jeff Rogg ◽  
Gerhard M. Friehs
Keyword(s):  
Mr Imaging ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Cranial Nerve ◽  
Fusion Imaging ◽  
Vascular Compression ◽  
Content Type ◽  
History Of ◽  
Fine Print

Object.The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.Methods.Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.Conclusions.The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.

Gamma knife radiosurgery for trigeminal neuralgia: the dry-eye complication

2002 ◽  
Vol 97 ◽  
pp. 525-528 ◽  
Author(s):  
Shinji Matsuda ◽  
Toru Serizawa ◽  
Makato Sato ◽  
Junichi Ono
Keyword(s):  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Dry Eye ◽  
Trigeminal Nerve ◽  
Gamma Knife Radiosurgery ◽  
Ophthalmological Examination ◽  
Related Factors ◽  
Content Type ◽  
Fine Print

Object. The purpose of this paper is to report a unique complication of gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). The nature of this complication and its related factors are discussed. Methods. Forty-one medically refractory patients with TN were treated with GKS. All patients received 80 Gy to the proximal trigeminal nerve root, using a 4-mm collimator and a single isocenter. Follow up consisted of three monthly outpatient sessions after GKS. Improvement, recurrence, complications, and changes in magnetic resonance imaging were recorded. To evaluate the factors behind the complications, a subgroup of 33 patients was assessed in whom the follow-up duration was more than 9 months. The follow-up duration was 3 to 36 months (mean 13 months). The results were excellent in 20 patients, good in 11, and fair in seven. No patient had a poor result. Three patients suffered recurrences. Seven patients suffered complications 9 to 24 months after GKS. All seven patients complained of facial numbness and hypesthesia was recorded. Three of them also complained of “dry eye” with diminution or absence of corneal reflex but no other abnormalities of the cornea and conjunctiva were found on ophthalmological examination. In these three patients, hypesthesia of the first division of the trigeminal nerve area had been found before their “dry eye” symptoms appeared. The irradiated volume on the brainstem was significantly related to this complication. Conclusions. The dry eye symptom seems to be a special form of sensory disturbance. An overdose of radiation to the brainstem may play an important role in the manifestation of this complication.

Gamma knife radiosurgery for trigeminal neuralgia: dose—volume histograms of the brainstem and trigeminal nerve

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 155-158 ◽  
Author(s):  
Ronald Brisman ◽  
R. Mooij
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Maximum Dose ◽  
Gamma Knife Radiosurgery ◽  
Content Type ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Fine Print

Object. The purpose of this study was to assess the relationship between the volume of brainstem that receives 20% or more of the maximum dose (VB20) and the volume of the trigeminal nerve that receives 50% or more of the maximum dose (VT50) on clinical outcome following gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). Methods. Patients with TN were treated with a single 4-mm isocenter with a maximum dose of 75 Gy directed at the trigeminal nerve close to where it leaves the brainstem. The VB20 and VT50, as determined on dose—volume histograms, were correlated with clinical outcomes at 6 and 12 months, laterality, presence of multiple sclerosis (MS), and each other. At 6 months excellent pain relief (no pain or required medicine) was achieved in 27 of 48 patients (p = 0.009) when VB20 was greater than or equal to 20 mm3 and in 25 of 78 when VB20 was less than 20 mm3, when all patients are considered. At 12 months excellent pain relief was achieved in 16 of 32 patients (p = 0.038) when VB20 was greater than or equal to 20 mm3 and in 14 of 52 when VB20 less than 20 mm3, when all patients are considered. When VB20 was less than 20 mm3 in MS patients, five of 21 had an excellent result at 6 months and two of 13 at 12 months. The VB20 was 20 mm3 or more in 38 of 64 on the right side and in eight of 41 on the left side (p < 0.001) in patients with TN and without MS. There is a difference between left and right dose—volume histograms even when the same isodose is placed on the surface of the brainstem. The VB20 was 20 mm3 or more in 45 of 105 patients with TN and without MS but in only three of 21 patients with TN and MS (p = 0.014). There was an inverse relationship between VB20 and VT50 (p = 0.01). Conclusions. Isocenter proximity to the brainstem, as reflected in a higher VB20, is associated with a greater chance of excellent outcome at 6 and 12 months. Worse results in patients with TN and MS may be partly explained by a lower VB20.

Targeting the cranial nerve: microradiosurgery for trigeminal neuralgia with CISS and 3D-Flash MR imaging sequences

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 107-110 ◽  
Author(s):  
Vasilios A. Zerris ◽  
Georg C. Noren ◽  
William A. Shucart ◽  
Jeff Rogg ◽  
Gerhard M. Friehs
Keyword(s):  
Mr Imaging ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Cranial Nerve ◽  
Fusion Imaging ◽  
Vascular Compression ◽  
Content Type ◽  
History Of ◽  
Fine Print

Object. The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression. Methods. Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients. In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy. Conclusions. The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.

Unusual causes of trigeminal neuralgia treated by gamma knife radiosurgery

2002 ◽  
Vol 97 ◽  
pp. 533-535 ◽  
Author(s):  
Jin Woo Chang ◽  
Jae Young Choi ◽  
Young Sul Yoon ◽  
Yong Gou Park ◽  
Sang Sup Chung
Keyword(s):  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Fourth Ventricle ◽  
Gamma Knife Radiosurgery ◽  
Brain Magnetic Resonance Imaging ◽  
Resonance Imaging ◽  
Segmental Demyelination ◽  
Content Type ◽  
Clinical Responses ◽  
Fine Print

✓ The purpose of this paper was to present two cases of secondary trigeminal neuralgia (TN) with an unusual origin and lesion location. In two cases TN was caused by lesions along the course of the trigeminal nerve within the pons and adjacent to the fourth ventricle. Both cases presented with typical TN. Brain magnetic resonance imaging revealed linear or wedge-shaped lesions adjacent to the fourth ventricle, extending anterolaterally and lying along the pathway of the intraaxial trigeminal fibers. The involvement of the nucleus of the spinal trigeminal tract and of the principal sensory trigeminal nucleus with segmental demyelination are suggested as possible causes for trigeminal pain in these cases. It is postulated that these lesions are the result of an old viral neuritis. The patients underwent gamma knife radiosurgery and their clinical responses have been encouraging to date.

Geometrical accuracy of the Novalis stereotactic radiosurgery system for trigeminal neuralgia

2004 ◽  
Vol 101 (Supplement3) ◽  
pp. 351-355 ◽  
Author(s):  
Javad Rahimian ◽  
Joseph C. Chen ◽  
Ajay A. Rao ◽  
Michael R. Girvigian ◽  
Michael J. Miller ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Trigeminal Neuralgia ◽  
Image Fusion ◽  
Stereotactic Radiosurgery ◽  
Ct Images ◽  
Radiochromic Film ◽  
Quality Assurance Program ◽  
Content Type ◽  
Geometrical Accuracy ◽  
Fine Print

Object. Stringent geometrical accuracy and precision are required in the stereotactic radiosurgical treatment of patients. Accurate targeting is especially important when treating a patient in a single fraction of a very high radiation dose (90 Gy) to a small target such as that used in the treatment of trigeminal neuralgia (3 to 4—mm diameter). The purpose of this study was to determine the inaccuracies in each step of the procedure including imaging, fusion, treatment planning, and finally the treatment. The authors implemented a detailed quality-assurance program. Methods. Overall geometrical accuracy of the Novalis stereotactic system was evaluated using a Radionics Geometric Phantom Chamber. The phantom has several magnetic resonance (MR) and computerized tomography (CT) imaging—friendly objects of various shapes and sizes. Axial 1-mm-thick MR and CT images of the phantom were acquired using a T1-weighted three-dimensional spoiled gradient recalled pulse sequence and the CT scanning protocols used clinically in patients. The absolute errors due to MR image distortion, CT scan resolution, and the image fusion inaccuracies were measured knowing the exact physical dimensions of the objects in the phantom. The isocentric accuracy of the Novalis gantry and the patient support system was measured using the Winston—Lutz test. Because inaccuracies are cumulative, to calculate the system's overall spatial accuracy, the root mean square (RMS) of all the errors was calculated. To validate the accuracy of the technique, a 1.5-mm-diameter spherical marker taped on top of a radiochromic film was fixed parallel to the x–z plane of the stereotactic coordinate system inside the phantom. The marker was defined as a target on the CT images, and seven noncoplanar circular arcs were used to treat the target on the film. The calculated system RMS value was then correlated with the position of the target and the highest density on the radiochromic film. The mean spatial errors due to image fusion and MR imaging were 0.41 ± 0.3 and 0.22 ± 0.1 mm, respectively. Gantry and couch isocentricities were 0.3 ± 0.1 and 0.6 ± 0.15 mm, respectively. The system overall RMS values were 0.9 and 0.6 mm with and without the couch errors included, respectively (isocenter variations due to couch rotation are microadjusted between couch positions). The positional verification of the marker was within 0.7 ± 0.1 mm of the highest optical density on the radiochromic film, correlating well with the system's overall RMS value. The overall mean system deviation was 0.32 ± 0.42 mm. Conclusions. The highest spatial errors were caused by image fusion and gantry rotation. A comprehensive quality-assurance program was developed for the authors' stereotactic radiosurgery program that includes medical imaging, linear accelerator mechanical isocentricity, and treatment delivery. For a successful treatment of trigeminal neuralgia with a 4-mm cone, the overall RMS value of equal to or less than 1 mm must be guaranteed.

Gamma knife surgery for trigeminal neuralgia: improved initial response with two isocenters and increasing dose

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 185-188 ◽  
Author(s):  
Tracy E. Alpert ◽  
Chung T. Chung ◽  
Lisa T. Mitchell ◽  
Charles J. Hodge ◽  
Craig T. Montgomery ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Linear Regression Analysis ◽  
Initial Response ◽  
Gamma Knife Surgery ◽  
Invasive Treatment ◽  
Content Type ◽  
Improvement Score ◽  
Fine Print

Object. The authors sought to evaluate the initial response of trigeminal neuralgia (TN) to gamma knife surgery (GKS) based on the number of shots delivered and radiation dose. Methods. Between September 1998 and September 2003, some 63 patients with TN refractory to medical or surgical management underwent GKS at Upstate Medical University. Ten patients had multiple sclerosis and 25 patients had undergone prior invasive treatment. Gamma knife surgery was delivered to the trigeminal nerve root entry zone in one shot in 27 patients or two shots in 36 patients. The radiation dose was escalated to less than or equal to 80 Gy in 20 patients, 85 Gy in 21 patients, and greater than or equal to 90 Gy in 22 patients. Pain before and after GKS was assessed using the Barrow Neurological Institute Pain Scale and the improvement score was analyzed as a function of dose grouping and number of shots. Sixty patients were available for evaluation, with an initial overall and complete response rate of 90% and 27%, respectively. There was a greater improvement score for patients who were treated with two shots compared with one shot, mean 2.83 compared with 1.72 (p < 0.001). There was an increased improvement in score at each dose escalation level: less than or equal to 80 Gy (p = 0.017), 85 Gy (p < 0.001), and greater than or equal to 90 Gy (p < 0.001). Linear regression analysis also indicated that there was a greater response with an increased dose (p = 0.021). Patients treated with two shots were more likely to receive a higher dose (p < 0.001). There were no severe complications. Five patients developed mild facial numbness. Conclusions. Gamma knife surgery is an effective therapy for TN. Initial response rates appear to correlate with the number of shots and dose.

Evaluation of endorphin content in the CSF of patients with trigeminal neuralgia before and after Gasserian ganglion thermocoagulation

1981 ◽  
Vol 55 (6) ◽  
pp. 935-937 ◽  
Author(s):  
Giuseppe Salar ◽  
Salvatore Mingrino ◽  
Marco Trabucchi ◽  
Angelo Bosio ◽  
Carlo Semenza
Keyword(s):  
Cerebrospinal Fluid ◽  
Trigeminal Neuralgia ◽  
Control Group ◽  
Gasserian Ganglion ◽  
Content Type ◽  
Group Of Seven ◽  
Idiopathic Trigeminal Neuralgia ◽  
Significant Difference ◽  
Before And After ◽  
Fine Print

✓ The β-endorphin content in cerebrospinal fluid (CSF) was evaluated in 10 patients with idiopathic trigeminal neuralgia during medical treatment (with or without carbamazepine) and after selective thermocoagulation of the Gasserian ganglion. These values were compared with those obtained in a control group of seven patients without pain problems. No statistically significant difference was found between patients suffering from trigeminal neuralgia and those without pain. Furthermore, neither pharmacological treatment nor surgery changed CSF endorphin values. It is concluded that there is no pathogenetic relationship between trigeminal neuralgia and endorphins.

Gamma knife surgery with a dose of 75 to 76.8 Gray for trigeminal neuralgia

2004 ◽  
Vol 100 (5) ◽  
pp. 848-854 ◽  
Author(s):  
Ronald Brisman
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Recurrent Pain ◽  
Content Type ◽  
Kaplan Meier ◽  
Uniform Manner ◽  
Second Procedure ◽  
Fine Print

Object. The author presents a large series of patients with idiopathic trigeminal neuralgia (TN) who were treated with gamma knife surgery (GKS), at a maximum dose of 75 to 76.8 Gy, and followed up in a nearly uniform manner for up to 4.6 years. Methods. Two hundred ninety-three patients were treated and followed up for at least 6 months (range 0.4–4.6 years, median 1.9 years). At the final follow-up review, there was complete (100%) pain relief without medicines in 64 patients (21.8%), 90% or greater relief with or without small doses of medicines in 86 (29.4%), between 75 and 89% relief in 31 (10.6%), between 50 and 74% relief in 19 (6.5%), and less than 50% relief in 23 patients (7.8%). Recurrent pain requiring a second procedure occurred in 70 patients (23.9%). Kaplan—Meier analysis showed that 100%, 90% or greater, and 50% or greater pain relief was obtained and maintained for 3.5 to 4.1 years in 5.6 , 23.7, and 50.4% patients, respectively. Of 31 patients who described pain relief ranging from 75 to 89%, 80% of patients described it as good and 10% as excellent; of 17 patients who reported between 50 and 74% pain relief, 53% described it as good and none as excellent (p = 0.014). Dysesthesia scores greater than 5 (scale of 0–10, in which a score of 10 represents excruciating pain) occurred in four (3.2%) of 126 patients who had not undergone prior surgery; all these patients obtained either good or excellent relief from TN pain. There were 36 patients in whom the TN had atypical features; these patients were less likely to attain at least 50% or at least 90% pain relief compared with those without atypical TN features (p = 0.001). Conclusions. Gamma knife surgery is a safe and effective way to relieve TN. Patients who attain between 75 and 89% pain relief are much more likely to describe this outcome as good or excellent than those who attain between 50 and 74% pain relief.

Long-term outcome after operation for trigeminal neuralgia in patients with posterior fossa tumors

1996 ◽  
Vol 84 (5) ◽  
pp. 818-825 ◽  
Author(s):  
Fred G. Barker ◽  
Peter J. Jannetta ◽  
Ramesh P. Babu ◽  
Spiros Pomonis ◽  
David J. Bissonette ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Posterior Fossa ◽  
Trigeminal Nerve ◽  
Posterior Fossa Tumors ◽  
Duration Of Symptoms ◽  
Long Term Outcome ◽  
Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Fine Print

✓ During a 20-year period, 26 patients with typical symptoms of trigeminal neuralgia were found to have posterior fossa tumors at operation. These cases included 14 meningiomas, eight acoustic neurinomas, two epidermoid tumors, one angiolipoma, and one ependymoma. The median patient age was 60 years and 69% of the patients were women. Sixty-five percent of the symptoms were left sided. The median preoperative duration of symptoms was 5 years. The distribution of pain among the three divisions of the trigeminal nerve was similar to that found in patients with trigeminal neuralgia who did not have tumors; however, more divisions tended to be involved in the tumor patients. The mean postoperative follow-up period was 9 years. At operation, the root entry zone of the trigeminal nerve was examined for vascular cross-compression in 21 patients. Vessels compressing the nerve at the root entry zone were observed in all patients examined. Postoperative pain relief was frequent and long lasting. Using Kaplan—Meier methods the authors estimated excellent relief in 81% of the patients 10 years postoperatively, with partial relief in an additional 4%.

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