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Lynn S Ashby - One of the best experts on this subject based on the ideXlab platform.
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Gamma Knife surgery targeting the Centromedian Nucleus of the thalamus for the palliative management of thalamic pain: durable response in stroke-induced thalamic pain syndrome.
Journal of Neurosurgery, 2006Co-Authors: Marcus F Keep, Lois Mastrofrancesco, Arthur D. Craig, Lynn S AshbyAbstract:The authors report the neuroimaging features, treatment planning, and outcome in a case of radiosurgical thalamotomy targeting the Centromedian Nucleus (CMN) for stroke-induced thalamic pain. A 79-year-old man, with embolic occlusion of the left middle cerebral artery and large hemispheric infarction involving the thalamus, suffered a right hemiplegia and expressive aphasia. One year poststroke, severe right-sided facial, scalp, arm, and trunk pain developed and was exacerbated by any tactile contact. Medical treatment had failed. Medical illness, including mandatory anticoagulation therapy for atrial fibrillation, precluded surgical procedures. Minimally invasive radiosurgery was offered as an alternative. Magnetic resonance imaging and computed tomography were used to localize the left CMN. A single shot of 140 Gy was delivered to the 100% isodose line by using the 4-mm collimator helmet. The patient was evaluated at regular intervals. By 12 weeks posttreatment, he had significant improvements in pain control and his ability to tolerate physical contact during activities of daily living. Magnetic resonance imaging demonstrated baseline encephalomalacia from his prior stroke, and signal changes in the left CMN consistent with gamma irradiation-based thalamotomy. Currently, nearly 7 years after radiosurgery, he continues to enjoy a marked reduction in pain without the need of analgesic medications. Thalamic pain syndrome is generally refractory to conventional treatment. Neurosurgical interventions provide modest benefit and carry associated risks of invasive surgery and anesthesia. The CMN is readily localized with neuroimaging and is an approximate target to reduce the suffering aspect of pain. In this case, radiosurgery was a safe and effective treatment, providing durable symptom control and improved quality of life.
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Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the Centromedian Nucleus of the thalamus.
Journal of neurosurgery, 2005Co-Authors: Marcus F Keep, Paul A Demare, Lynn S AshbyAbstract:The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and Centromedian Nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the Centromedian Nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75-100%), good (50-75%), poor (25-50%); or none (0-25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Combined GKS of the Centromedian Nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
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Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the Centromedian Nucleus of the thalamus
Journal of Neurosurgery, 2005Co-Authors: Marcus F Keep, Paul A Demare, Lynn S AshbyAbstract:Object. The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Methods. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and Centromedian Nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the Centromedian Nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75–100%), good (50–75%), poor (25–50%), or none (0–25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Conclusions. Combined GKS of the Centromedian Nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
Marcus F Keep - One of the best experts on this subject based on the ideXlab platform.
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Gamma Knife surgery targeting the Centromedian Nucleus of the thalamus for the palliative management of thalamic pain: durable response in stroke-induced thalamic pain syndrome.
Journal of Neurosurgery, 2006Co-Authors: Marcus F Keep, Lois Mastrofrancesco, Arthur D. Craig, Lynn S AshbyAbstract:The authors report the neuroimaging features, treatment planning, and outcome in a case of radiosurgical thalamotomy targeting the Centromedian Nucleus (CMN) for stroke-induced thalamic pain. A 79-year-old man, with embolic occlusion of the left middle cerebral artery and large hemispheric infarction involving the thalamus, suffered a right hemiplegia and expressive aphasia. One year poststroke, severe right-sided facial, scalp, arm, and trunk pain developed and was exacerbated by any tactile contact. Medical treatment had failed. Medical illness, including mandatory anticoagulation therapy for atrial fibrillation, precluded surgical procedures. Minimally invasive radiosurgery was offered as an alternative. Magnetic resonance imaging and computed tomography were used to localize the left CMN. A single shot of 140 Gy was delivered to the 100% isodose line by using the 4-mm collimator helmet. The patient was evaluated at regular intervals. By 12 weeks posttreatment, he had significant improvements in pain control and his ability to tolerate physical contact during activities of daily living. Magnetic resonance imaging demonstrated baseline encephalomalacia from his prior stroke, and signal changes in the left CMN consistent with gamma irradiation-based thalamotomy. Currently, nearly 7 years after radiosurgery, he continues to enjoy a marked reduction in pain without the need of analgesic medications. Thalamic pain syndrome is generally refractory to conventional treatment. Neurosurgical interventions provide modest benefit and carry associated risks of invasive surgery and anesthesia. The CMN is readily localized with neuroimaging and is an approximate target to reduce the suffering aspect of pain. In this case, radiosurgery was a safe and effective treatment, providing durable symptom control and improved quality of life.
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Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the Centromedian Nucleus of the thalamus.
Journal of neurosurgery, 2005Co-Authors: Marcus F Keep, Paul A Demare, Lynn S AshbyAbstract:The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and Centromedian Nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the Centromedian Nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75-100%), good (50-75%), poor (25-50%); or none (0-25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Combined GKS of the Centromedian Nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
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Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the Centromedian Nucleus of the thalamus
Journal of Neurosurgery, 2005Co-Authors: Marcus F Keep, Paul A Demare, Lynn S AshbyAbstract:Object. The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Methods. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and Centromedian Nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the Centromedian Nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75–100%), good (50–75%), poor (25–50%), or none (0–25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Conclusions. Combined GKS of the Centromedian Nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
Yoland Smith - One of the best experts on this subject based on the ideXlab platform.
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Structural plasticity of GABAergic and glutamatergic networks in the motor thalamus of parkinsonian monkeys.
The Journal of comparative neurology, 2019Co-Authors: Ashley J. Swain, Adriana Galván, Thomas Wichmann, Yoland SmithAbstract:In the primate thalamus, the parvocellular ventral anterior Nucleus (VApc) and the Centromedian Nucleus (CM) receive GABAergic projections from the internal globus pallidus (GPi) and glutamatergic inputs from motor cortices. In this study, we used electron microscopy to assess potential structural changes in GABAergic and glutamatergic microcircuits in the VApc and CM of MPTP-treated parkinsonian monkeys. The intensity of immunostaining for GABAergic markers in VApc and CM did not differ between control and parkinsonian monkeys. In the electron microscope, three major types of terminals were identified in both nuclei: (a) vesicular glutamate transporter 1 (vGluT1)-positive terminals forming asymmetric synapses (type As), which originate from the cerebral cortex, (b) GABAergic terminals forming single symmetric synapses (type S1), which likely arise from the reticular Nucleus and GABAergic interneurons, and (c) GABAergic terminals forming multiple symmetric synapses (type S2), which originate from GPi. The density of As terminals outnumbered that of S1 and S2 terminals in VApc and CM of control and parkinsonian animals. No significant change was found in the abundance and synaptic connectivity of S1 and S2 terminals in VApc or CM of MPTP-treated monkeys, while the prevalence of "As" terminals in VApc of parkinsonian monkeys was 51.4% lower than in controls. The cross-sectional area of vGluT1-positive boutons in both VApc and CM of parkinsonian monkeys was significantly larger than in controls, but their pattern of innervation of thalamic cells was not altered. Our findings suggest that the corticothalamic system undergoes significant synaptic remodeling in the parkinsonian state.
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Lrrk2 localization in the primate basal ganglia and thalamus: a light and electron microscopic analysis in monkeys.
Experimental neurology, 2010Co-Authors: Heyne Lee, Heather L. Melrose, Mei Yue, Jean Francois Pare, Matthew J. Farrer, Yoland SmithAbstract:The Leucine Rich Repeat Kinase-2 (LRRK2) gene is a common mutation target in Parkinson's disease (PD), but the cellular mechanisms by which such mutations underlie the pathophysiology of PD remain poorly understood. Thus, to better characterize the neuronal target sites of LRRK2 mutations in the primate brain, we studied the cellular and ultrastructural localization of Lrrk2 immunoreactivity in the monkey basal ganglia. As previously described, the monkey striatum was the most enriched basal ganglia structure in Lrrk2 labeling. Both projection neurons and parvalbumin-containing GABAergic interneurons displayed Lrrk2 immunoreactivity. At the electron microscopic level, striatal Lrrk2 labeling was associated predominantly with dendritic shafts and subsets of putative glutamatergic axon terminals. At the pallidal level, moderate cellular Lrrk2 immunostaining was found in the external globus pallidus (GPe), while neurons in the internal globus pallidus (GPi) were devoid of Lrrk2 immunoreactivity. Strong labeling was associated with cholinergic neurons in the Nucleus basalis of Meynert. Midbrain dopaminergic neurons in the primate substantia nigra pars compacta (SNc) and ventral tegmental area harbored a significant level of Lrrk2 labeling, while neurons in the subthalamic Nucleus were lightly immunostained. Most thalamic nuclei were enriched in Lrrk2 immunoreactivity, except for the Centromedian Nucleus that was completely devoid of labeling. Thus, Lrrk2 protein is widely distributed in the monkey basal ganglia, suggesting that gene mutations in PD may result in multifarious pathophysiological effects that could impact various target sites in the functional circuitry of the primate basal ganglia.
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Effects of stimulation of the Centromedian Nucleus of the thalamus on the activity of striatal cells in awake rhesus monkeys.
The European journal of neuroscience, 2009Co-Authors: Bijli Nanda, Yoland Smith, Adriana Galván, Thomas WichmannAbstract:Although the existence of a massive projection from the caudal intralaminar nuclei of the thalamus (i.e., the Centromedian and parafascicular nuclei, CM/PF) to the striatum is well documented, the effects of CM activation upon striatal cells remain poorly understood. Therefore, we studied the effects of electrical stimulation of CM on the electrophysiological activity of striatal neurons, and on striatal levels of gamma-aminobutyric acid (GABA) and acetylcholine in rhesus monkeys. Striatal cells did not respond to single pulse stimulation (bipolar biphasic stimulation, 175–500 µA), but the large majority of recorded neurons responded to burst stimulation (100 Hz, 1 sec, 150–175 µA) of CM, often with a delay of tens of milliseconds. Striatal phasically active neurons, which likely correspond to projection neurons, responded mainly with increases in firing (13/28 cells), while tonically active neurons (likely cholinergic interneurons), often showed combinations of increases and decreases in firing (24/46 cells). In microdialysis studies, CM stimulation lead to a reduction of striatal acetylcholine levels. This effect was prevented by addition of the GABA-A receptor antagonist gabazine to the microdialysis fluid. We conclude that CM stimulation frequently results in striatal response patterns with excitatory and inhibitory components. Under the conditions chosen here, the specific patterns of striatal responses to CM stimulation are likely the result of striatal processing of thalamic inputs. Through these indirect effects, local CM stimulation may engage large portions of the striatum. These effects may be relevant in the interpretation of the therapeutic effects of CM-stimulation for the treatment of neurologic disorders.
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Thalamic inputs to striatal interneurons in monkeys: synaptic organization and co-localization of calcium binding proteins.
Neuroscience, 1999Co-Authors: M Sidibé, Yoland SmithAbstract:Abstract Recent studies indicate that extrinsic inputs from sensorimotor regions of the cerebral cortex and the Centromedian intralaminar thalamic Nucleus terminate preferentially upon specific subpopulations of striatal output neurons in monkeys. The objective of the present study was to verify whether this specificity of innervation also characterizes the synaptic interactions between thalamic inputs from the Centromedian Nucleus and the four major populations of striatal interneurons. This was achieved by double labelling techniques at the electron microscope level, combining the anterograde transport of biotinylated-dextran amine with the immunostaining for specific markers of striatal interneurons (somatostatin, parvalbumin, choline acetyltransferase and calretinin). Injections of biotinylated-dextran amine in the Centromedian Nucleus led to dense bands of anterograde labelling which, in double immunostained sections, largely overlapped with the four populations of interneurons in the post-commissural region of the putamen. In the electron microscope, biotinylated-dextran amine-containing terminals formed asymmetric axo-dendritic synapses with somatostatin-, parvalbumin-, and choline acetyltransferase-containing elements. However, synapses between anterogradely labelled terminals and calretinin-positive neurons were not found. In sections processed to localize biotinylated-dextran amine and parvalbumin or calretinin, double-labelled terminals (biotinylated-dextran amine/parvalbumin and biotinylated-dextran amine/calretinin), morphologically similar to thalamostriatal boutons, were found in the striatum indicating that calcium binding proteins may be expressed by thalamostriatal neurons. To test this possibility, we combined the retrograde transport of lectin-conjugated horseradish peroxidase from the putamen with parvalbumin and calretinin immunostaining and found that, indeed, most of the retrogradely labelled cells in the Centromedian Nucleus displayed parvalbumin and calretinin immunoreactivity. Moreover, co-localization studies revealed that calretinin and parvalbumin co-exist in single neurons of the Centromedian Nucleus. In conclusion, striatal interneurons immunoreactive for somatostatin, parvalbumin and choline acetyltransferase, but not those containing calretinin, receive strong inputs from the Centromedian Nucleus in monkeys. Moreover, our findings indicate that parvalbumin and calretinin co-exist in individual thalamostriatal neurons. In combination with our previous data, these results suggest that thalamic information may be conveyed to striatal projection neurons both, directly via excitatory synaptic inputs, or indirectly via striatal interneurons. The relative importance of those direct and indirect thalamic influences upon the activity of striatal output neurons remains to be established.
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Differential synaptic innervation of striatofugal neurones projecting to the internal or external segments of the globus pallidus by thalamic afferents in the squirrel monkey
The Journal of comparative neurology, 1996Co-Authors: Mamadou Sidibé, Yoland SmithAbstract:It is well established that the Centromedian Nucleus (CM) is the major source of thalamic afferents to the sensorimotor territory of the striatum in monkeys. However, the projection sites of striatal neurones contacted by thalamic afferents still remain to be determined. We therefore carried out an anatomical study aimed at elucidating the hodology of striatal neurones that receive input from the CM in squirrel monkeys. Our approach was to combine the anterograde transport of Phaseolus vulgaris-leucoagglutinin (PHA-L) or biocytin from the CM with the retrograde transport of biotinylated dextran-amine (bio-dex) or PHA-L from the internal (GPi) or external (GPe) segments of the globus pallidus. Following CM injections, rich plexuses of anterogradely labelled, thin varicose fibres aggregated in the form of bands that were confined to the postcommissural region of the putamen. On the other hand, injections into the GPe or GPi led to profuse retrograde labelling of a multitude of medium-sized spiny neurones. In cases where the injections involved the caudoventral two-thirds of the GPe or GPi, the retrogradely labelled striatopallidal cells and the anterogradely labelled thalamostriatal fibres occurred in the sensorimotor territory of the putamen. After injections into either pallidal segments, clusters of retrogradely labelled cells were in register with bands of anterogradely labelled thalamic fibres. However, electron microscopic analysis of striatal regions containing both anterogradely labelled thalamic afferents and retrogradely labelled cells revealed that terminals from the CM frequently form asymmetric synapses with dendritic shafts and spines of striato-GPi cells but rarely with those of striato-GPe cells. In conclusion, our findings demonstrate that thalamic afferents from the CM innervate preferentially striatopallidal neurones projecting to the GPi in monkeys. These results indicate that the striatopallidal neurones contributing to the “direct” and “indirect” output pathways are differentially innervated by thalamic afferents in primates. © 1996 Wiley-Liss, Inc.
Katsuma Nakano - One of the best experts on this subject based on the ideXlab platform.
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projections of the vestibular nuclei to the thalamus in the rat a phaseolus vulgaris leucoagglutinin study
The Journal of Comparative Neurology, 1999Co-Authors: Takashi Shiroyama, Tetsuro Kayahara, Yukihiko Yasui, Junichi Nomura, Katsuma NakanoAbstract:Injections of the anterograde axonal tracer Phaseolus vulgaris leucoagglutinin were made into individual nuclei of the vestibular nuclear complex of the rat to identify specific projections to the thalamus. The results showed that the superior vestibular Nucleus and the medial vestibular Nucleus, especially its rostral-to-middle parts, project to the lateral part of the parafascicular thalamic Nucleus (corresponding to the Centromedian Nucleus in primates), the transitional zone between the ventrolateral thalamic Nucleus (VL) and the ventral posterolateral thalamic Nucleus (VPL) (the region considered to be the Nucleus ventralis intermedius of Vogt [Vogt C. 1909. La myeloarchitecture du thalamus du cercopitheque. J Psychol Neurol 12:285-324.]), the lateral part of the centrolateral thalamic Nucleus and the dorsal part of the caudal VL; the spinal vestibular Nucleus projects to the lateral part of the parafascicular thalamic Nucleus, the transitional zone between the VL and the VPL, the caudal part of the ventrobasal complex, and the suprageniculate thalamic Nucleus. These results suggest that vestibular information is transmitted not only to the cerebral cortex (mainly area 2V and area 3a) but also to the striatum. They also suggest that vestibular activity may affect gaze control by means of vestibulothalamocortical pathway in addition to vestibulo-ocular and vestibulopremotoneuronal routes.
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the vestibular nuclei of the rat project to the lateral part of the thalamic parafascicular Nucleus Centromedian Nucleus in primates
Brain Research, 1995Co-Authors: Takashi Shiroyama, Tetsuro Kayahara, Yukihiko Yasui, Junichi Nomura, Katsuma NakanoAbstract:To clarify the vestibular projections to the Centromedian-parafascicular nuclear complex, the Phaseolus vulgaris leucoagglutinin (PHA-L) and horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP), tracing studies have been done in rats. The data demonstrated that the lateral parafasicular Nucleus received vestibular afferents mainly from the ventral part of medial vestibular Nucleus, and the superior and inferior vestibular nuclei, with an ipsilateral predominance. These findings suggest the vestibular influence to the motor loop of the basal ganglia thalamocortical projections.
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Pallidal Afferents to the Neurons in the Anterior Thalamic Reticular Nucleus Projecting to the Centromedian Nucleus
Advances in Behavioral Biology, 1994Co-Authors: Tetsuro Kayahara, Yukihiko Yasui, Katsuma NakanoAbstract:The thalamic reticular Nucleus is a thin layer of neurons interposed between the internal capsule laterally and the external medullary lamina medially, and covers the rostral and lateral aspects of the thalamus. This Nucleus receives inputs from collaterals of both corticothalamic and thalamocortical axons (Jones, 1985). Cells of this Nucleus in turn send their axons back into the thalamus, and innervate both relay cells and local GABAergic interneurons (for review see Steriade and Deschenes, 1984).
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Topographical Organization of the Thalamostriatal Projection in the Japanese Monkey, Macaca Fuscata , with Special Reference to the Centromedian-Parafascicular and Motor Thalamic Nuclei
Advances in Behavioral Biology, 1991Co-Authors: Katsuma Nakano, Tetsuro Kayahara, Yasuo Hasegawa, Yoshihiro KugaAbstract:Thalamostriatal projection was studied in monkeys (Macaca fuscata) using the axonal transport techniques of WGA-HRP and autoradiography to clarify the topographical organization. Major findings were as follows: The dorsomedial part of the Centromedian Nucleus (CM) projects to the dorsolateral strip in the leg territory of the putamen (Put); the ventromedial CM projects to the ventromedial strip in the face area; and the lateral CM projects to the intermediate strip in the arm region of the Put. The lateral part of the parafascicular Nucleus (Pf) and Nucleus ventralis anterior pars parvicellularis project to the lateral part of the head of the caudate Nucleus (CN) and to the dorsolateral part of the rostral Put. Whereas the medial Pf and Nucleus ventralis anterior pars magnocellularis project to the medial and ventral parts of the CN and to the ventromedial part of the rostral Put. The Nucleus ventralis lateralis pars oralis projects to the Put. The medial part of the Nucleus subthalamicus (STN) projects to the head of CN and rostral Put, while the lateral STN projects to the remaining whole part of the Put.
Paul A Demare - One of the best experts on this subject based on the ideXlab platform.
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Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the Centromedian Nucleus of the thalamus.
Journal of neurosurgery, 2005Co-Authors: Marcus F Keep, Paul A Demare, Lynn S AshbyAbstract:The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and Centromedian Nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the Centromedian Nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75-100%), good (50-75%), poor (25-50%); or none (0-25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Combined GKS of the Centromedian Nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
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Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the Centromedian Nucleus of the thalamus
Journal of Neurosurgery, 2005Co-Authors: Marcus F Keep, Paul A Demare, Lynn S AshbyAbstract:Object. The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Methods. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and Centromedian Nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the Centromedian Nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75–100%), good (50–75%), poor (25–50%), or none (0–25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Conclusions. Combined GKS of the Centromedian Nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.