Degree of distal trigeminal nerve atrophy predicts outcome after microvascular decompression for Type 1a trigeminal neuralgia

OBJECT Trigeminal neuralgia is often associated with nerve atrophy, in addition to vascular compression. The authors evaluated whether cross-sectional areas of different portions of the trigeminal nerve on preoperative imaging could be used to predict outcome after microvascular decompression (MVD). METHODS A total of 26 consecutive patients with unilateral Type 1a trigeminal neuralgia underwent high-resolution fast-field echo MRI of the cerebellopontine angle followed by MVD. Preoperative images were reconstructed and reviewed by 2 examiners blinded to the side of symptoms and clinical outcome. For each nerve, a computerized automatic segmentation algorithm was used to calculate the coronal cross-sectional area at the proximal nerve near the root entry zone and the distal nerve at the exit from the porus trigeminus. Findings were correlated with outcome at 12 months. RESULTS After MVD, 17 patients were pain free and not taking medications compared with 9 with residual pain. Across all cases, the coronal cross-sectional area of the symptomatic trigeminal nerve was significantly smaller than the asymptomatic side in the proximal part of the nerve, which was correlated with degree of compression at surgery. Atrophy of the distal trigeminal nerve was more pronounced in patients who had residual pain than in those with excellent outcome. Among the 7 patients who had greater than 20% loss of nerve volume in the distal nerve, only 2 were pain free and not taking medications at long-term follow-up. CONCLUSIONS Trigeminal neuralgia is associated with atrophy of the root entry zone of the affected nerve compared with the asymptomatic side, but volume loss in different segments of the nerve has very different prognostic implications. Proximal atrophy is associated with vascular compression and correlates with improved outcome following MVD. However, distal atrophy is associated with a significantly worse outcome after MVD.

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Microanatomy of the Central Myelin-Peripheral Myelin Transition Zone of the Trigeminal Nerve

Neurosurgery ◽

10.1227/01.neu.0000223501.27220.69 ◽

2006 ◽

Vol 59 (2) ◽

pp. 354-359 ◽

Cited By ~ 66

Author(s):

Selçuk Peker ◽

Özlem Kurtkaya ◽

İbrahim Üzün ◽

M Necmettin Pamir

Keyword(s):

Trigeminal Neuralgia ◽

Trigeminal Nerve ◽

Transitional Zone ◽

Vascular Compression ◽

Lateral Aspect ◽

Entry Zone ◽

Root Entry Zone ◽

Central Myelin ◽

Trigeminal Nerves ◽

Vascular Decompression

Abstract OBJECTIVE: The aim of this study was to evaluate the microanatomy of the central myelin-peripheral myelin transitional zone (TZ) in trigeminal nerves from cadavers. METHODS: One hundred trigeminal nerves from 50 cadaver heads were examined. The cisternal portion of the nerve (from the pons to Meckel's cave) was measured. Horizontal sections were stained and photographed. The photomicrographs were used to measure the extent of central myelin on the medial and lateral aspects of the nerve and to classify TZ shapes. RESULTS: The cisternal portions of the specimens ranged from 8 to 15 mm long (mean, 12.3 mm; median, 11.9 mm). The data from the photomicrographs revealed that the extent of central myelin (distance from pons to TZ) on the medial aspect of the nerve (range, 0.1–2.5 mm; mean, 1.13 mm; median, 1 mm) was shorter than that on the lateral aspect (range, 0.17–6.75 mm; mean, 2.47 mm; median, 2.12 mm). CONCLUSION: The data definitively prove that the root entry zone (REZ, nerve-pons junction) and TZ of the trigeminal nerve are distinct sites and that these terms should never be used interchangeably. The measurements showed that the central myelin occupies only the initial one-fourth of the trigeminal nerve length. If trigeminal neuralgia is caused exclusively by vascular compression of the central myelin, the problem vessel would always have to be located in this region. However, it is well known that pain from trigeminal neuralgia can resolve after vascular decompression at more distal sites. This suggests that the effects of surgical decompression are caused by another mechanism.

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Nerve atrophy and a small cerebellopontine angle cistern in patients with trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/2008.8.jns08522 ◽

2009 ◽

Vol 110 (4) ◽

pp. 633-637 ◽

Cited By ~ 28

Author(s):

Seong-Hyun Park ◽

Sung-Kyoo Hwang ◽

Sun-Ho Lee ◽

Jaechan Park ◽

Jeong-Hyun Hwang ◽

...

Keyword(s):

Mr Imaging ◽

Trigeminal Neuralgia ◽

Trigeminal Nerve ◽

Cerebellopontine Angle ◽

Cross Sectional Area ◽

Sectional Area ◽

Unaffected Side ◽

Cross Sectional ◽

Affected Side ◽

The Mean

Object The aim of this study was to provide information to help confirm the diagnosis of trigeminal neuralgia (TN) using MR imaging. Methods The authors evaluated atrophy of the trigeminal nerve, the cross-sectional area of the cerebellopontine angle (CPA) cistern, and the length of the cisternal segment of the trigeminal nerve on the affected side in 26 consecutive patients with TN who were treated using Gamma Knife surgery. Results The mean volume of the trigeminal nerve on the affected side was significantly smaller than the mean volume of the trigeminal nerve on the unaffected side (p < 0.001). Nerve atrophy was present in 25 patients (96.2%) on the affected side and in 1 patient on the unaffected side. The mean cross-sectional area of the CPA cistern on the affected side (188.5 mm2) was significantly smaller than the mean volume on the unaffected side (232.8 mm2) in 25 of the 26 patients (p = 0.001). The mean length of the cisternal segment of the trigeminal nerve on the affected side (7.9 mm) was significantly shorter than the mean length on the unaffected side (9.6 mm) in 25 of the 26 patients (p = 0.001). Conclusions Among the patients with TN, there was a statistically significant difference in the MR imaging findings of the affected side compared with the unaffected side of the trigeminal nerve. Atrophy of the trigeminal nerve and a small CPA cistern in patients with TN provides additional markers for the diagnosis of TN and helps confirm the diagnosis based on clinical examination.

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Microstructural changes in the trigeminal nerve of patients with episodic migraine assessed using magnetic resonance imaging

10.21203/rs.3.rs-16841/v2 ◽

2020 ◽

Author(s):

Tiffani J. Mungoven ◽

Noemi Meylakh ◽

Kasia Marciszewski ◽

Vaughan G. Macefield ◽

Paul M. Macey ◽

...

Keyword(s):

Trigeminal Nerve ◽

Episodic Migraine ◽

Radial Diffusion ◽

Sectional Area ◽

Resonance Imaging ◽

Cross Sectional ◽

Entry Zone ◽

Histological Evidence ◽

Root Entry Zone ◽

Migraine Pathophysiology

Abstract Background: There is histological evidence of microstructural changes in the zygomaticotemporal branch of the trigeminal nerve in migraineurs. This raises the possibility that altered trigeminal nerve properties contribute to migraine pathophysiology. Whilst it is not possible to explore the anatomy of small trigeminal nerve branches it is possible to explore the anatomy of the trigeminal root entry zone using magnetic resonance imaging in humans. The aim of this investigation is to assess the microstructure of the trigeminal nerve in vivo to determine if nerve alterations occur in individuals with episodic migraine. Methods: In 39 migraineurs and 39 matched controls, T1-weighted anatomical images were used to calculate the volume (mm3) and maximal cross-sectional area of the trigeminal nerve root entry zone; diffusion tensor images were used to calculate fractional anisotropy, mean diffusion, axial diffusion and radial diffusion. Results: There were significant differences between the left and right nerve of controls and migraineurs with respect to volume and not cross-sectional area. Migraineurs displayed reduced axial diffusion in the right nerve compared to the left nerve and reduced fractional anisotropy in the left nerve compared to left controls. Furthermore, although there were no differences in mean diffusion or radial diffusion, regional analysis of the nerve revealed significantly greater radial diffusion in the rostral portion of the left trigeminal nerve in migraineurs compared with controls. Conclusions: Migraine pathophysiology is associated with microstructural abnormalities within the trigeminal nerve that are consistent with histological evidence of altered myelin and/or organization. These peripheral nerve changes may provide further insight into migraine pathophysiology and enable a greater understanding for targeted treatments of pain alleviation.

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Microstructural changes in the trigeminal nerve of patients with episodic migraine assessed using magnetic resonance imaging

10.21203/rs.3.rs-16841/v1 ◽

2020 ◽

Author(s):

Tiffani J. Mungoven ◽

Noemi Meylakh ◽

Kasia Marcizewski ◽

Vaughan G. Macefield ◽

Paul M. Macey ◽

...

Keyword(s):

Trigeminal Nerve ◽

Episodic Migraine ◽

Radial Diffusion ◽

Sectional Area ◽

Resonance Imaging ◽

Cross Sectional ◽

Entry Zone ◽

Histological Evidence ◽

Root Entry Zone ◽

Migraine Pathophysiology

Abstract Background There is histological evidence of microstructural changes in the zygomaticotemporal branch of the trigeminal nerve in migraineurs. This raises the possibility that altered trigeminal nerve properties contribute to migraine pathophysiology. Whilst it is not possible to explore the anatomy of small trigeminal nerve branches it is possible to explore the anatomy of the trigeminal root entry zone using magnetic resonance imaging in humans. The aim of this investigation is to assess the microstructure of the trigeminal nerve in vivo to determine if nerve alterations occur in individuals with episodic migraine. Methods In 39 migraineurs and 39 matched controls, T1-weighted anatomical images were used to calculate the volume (mm 3 ) and maximal cross-sectional area of the trigeminal nerve root entry zone; diffusion tensor images were used to calculate fractional anisotropy, mean diffusion, axial diffusion and radial diffusion. Results Whilst there were no significant differences between controls and migraineurs with respect to volume or cross-sectional area, migraineurs displayed reduced fractional anisotropy. Furthermore, although there were no differences in average mean diffusion, axial diffusion or radial diffusion, regional analysis of the nerve revealed significantly greater mean diffusion and radial diffusion in the rostral portion of the trigeminal nerve in migraineurs compared with controls. Conclusions Migraine pathophysiology is associated with microstructural abnormalities within the trigeminal nerve that are consistent with histological evidence of altered myelin and/or organization. These peripheral nerve changes may provide further insight into migraine pathophysiology and enable a greater understanding for targeted treatments of pain alleviation.

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Trigeminal Neuralgia associated with Wallenberg Syndrome, a case report

10.5327/1516-3180.580 ◽

2021 ◽

Author(s):

Matheus Goncalves Maia ◽

Vivian Dias Baptista Gagliardi ◽

Francisco Tomaz Meneses Oliveira ◽

Eduardo dos Santos Sousa ◽

Marina Trombin Marques ◽

...

Keyword(s):

Case Report ◽

Trigeminal Neuralgia ◽

Trigeminal Nerve ◽

Vascular Compression ◽

Gasserian Ganglion ◽

Entry Zone ◽

Root Entry Zone ◽

Initial Event ◽

The Right ◽

The Brain

Context: Trigeminal neuralgia is typically associated with structural lesions that affect the brainstem, pre-ganglionic roots, gasserian ganglion and the trigeminal nerve. The association of trigeminal neuralgia with infarction of the dorsolateral medulla is rare, being more associated with pontine lesions, in the context of brainstem infarction. Methods: Report the case of a 55-year-old male patient, who presented with a left dorsolateral bulbar infarction, and developed a ipsilateral trigeminal neuralgia afterwards. Case report: A 55-year-old man attended to the emergency room referring sudden incoordination of the left limbs, associated with numbness of the contralateral limbs. The neurological examination showed nystagmus, numbness of the left face, ataxia of the left limbs and numbness of the right limbs. The Magnetic Resonance of the Brain revealed an area of recent infarction in the left posterolateral aspect of the medulla. He underwent thrombolysis, evolving with complete resolution of symptoms. In the week after the initial event, he returned to the outpatient clinic, reporting paroxysms of excruciating pain in the upper lip, nose and left zygomatic region, being diagnosed with neuralgia of the maxillary segment of the trigeminal nerve, improving with introduction of Gabapentin. Conclusion: Although most cases of trigeminal neuralgia are determined by vascular compression of the trigeminal nerve root entry zone, other causes must be considered. The association of this condition with dorsolateral medulla infarction is rare, with only 4 cases reported in the last 10 years.

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Significance of the cerebellopontine cistern cross-sectional area and trigeminal nerve anatomy in trigeminal neuralgia: an anatomical study using magnetic resonance imaging

Turkish Neurosurgery ◽

10.5137/1019-5149.jtn.27735-19.2 ◽

2019 ◽

Author(s):

Aylin Gunesli ◽

Kadir Tufan

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Trigeminal Neuralgia ◽

Trigeminal Nerve ◽

Anatomical Study ◽

Cross Sectional Area ◽

Sectional Area ◽

Resonance Imaging ◽

Cross Sectional

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Endoscope-Assisted Microvascular Decompression for Trigeminal Neuralgia:Technical Case Report

Operative Neurosurgery ◽

10.1227/01.neu.0000232768.47615.82 ◽

2006 ◽

Vol 59 (suppl_4) ◽

pp. ONS-E489-ONS-E490 ◽

Cited By ~ 11

Author(s):

Charles Teo ◽

Peter Nakaji ◽

Ralph J. Mobbs

Keyword(s):

Hearing Loss ◽

Case Report ◽

Trigeminal Neuralgia ◽

Wound Infection ◽

Trigeminal Nerve ◽

Microvascular Decompression ◽

Complication Rate ◽

Entry Zone ◽

Root Entry Zone

Abstract OBJECTIVE: Microvascular decompression may fail to relieve trigeminal neuralgia because a compressing vessel at the root entry zone may be overlooked during surgery. Alternatively, effective decompression may not always be achieved with the visualization provided by the microscope alone. We theorized that the addition of an endoscope would improve the efficacy of microvascular decompression. METHODS: We retrospectively reviewed microvascular decompression of the trigeminal nerve in 114 patients. Before closure, the endoscope was used to inspect the root entry zone. When visualization with the microscope was poor, the endoscope was used to identify an aberrant vessel and to perform or improve the subsequent decompression. RESULTS: Of 114 patients who underwent microvascular decompression, 113 successfully underwent endoscopy. In 38 patients (33%), endoscopy revealed arteries that were poorly seen (25%) or not seen at all (8%) with the microscope. At a mean follow-up period of 29 months, the pain was completely relieved in 112 patients (99.1%), all of whom were off medication. Complications included trigeminal dyses-thesias in nine patients and a wound infection, partial hearing loss, and complete hearing loss in one patient each. The overall complication rate was 9%. CONCLUSION: Endoscopy is a simple and safe adjunct to microscopic exploration of the trigeminal nerve. The markedly improved visualization increases the likelihood of identifying the offending vessel and consequently of achieving satisfactory decompression of the nerve. Thus far, the success rate has been high, and the complication profile is comparable to that of other large series.

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PREOPERATIVE SIMULATION FOR MICROVASCULAR DECOMPRESSION IN PATIENTS WITH IDIOPATHIC TRIGEMINAL NEURALGIA

Neurosurgery ◽

10.1227/01.neu.0000249213.34838.c9 ◽

2007 ◽

Vol 60 (1) ◽

pp. 104-114 ◽

Cited By ~ 37

Author(s):

Toru Satoh ◽

Keisuke Onoda ◽

Isao Date

Keyword(s):

Magnetic Resonance ◽

Trigeminal Neuralgia ◽

Trigeminal Nerve ◽

Microvascular Decompression ◽

Fusion Imaging ◽

Entry Zone ◽

Root Entry Zone ◽

Idiopathic Trigeminal Neuralgia ◽

Preoperative Simulation ◽

Magnetic Resonance Cisternography

Abstract OBJECTIVE Precise assessment of the complex nerve-vessel relationship at the root entry zone of the trigeminal nerve is useful for planning microvascular decompression in patients with idiopathic trigeminal neuralgia. We have applied a fusion imaging technique of three-dimensional (3-D) magnetic resonance cisternography and co-registered 3-D magnetic resonance angiography (MRA) that allows virtual reality for the preoperative simulation of the neurovascular conflict at the trigeminal nerve root entry zone. METHODS Fusion images of 3-D magnetic resonance cisternograms and angiograms were reconstructed by a perspective volume-rendering algorithm from the volumetric data sets of magnetic resonance cisternography, obtained by a T2-weighted 3-D fast spin echo sequence, and co-registered MRA, by a 3-D time-of-flight sequence. Consecutive series of 12 patients with idiopathic trigeminal neuralgia were studied with fusion 3-D magnetic resonance cisternogram and MRA in the preoperative assessment for the microvascular decompression of the affected trigeminal nerve. RESULTS The complex anatomical relationship of the offending vessels to the trigeminal nerve root entry zone was depicted on the fusion 3-D magnetic resonance cisternogram and MRA. The presence of offending vessels and compressive site of neurovascular conflict was assessed from the various viewpoints within the cistern and was presumed by the preoperative simulation through the surgical access (surgeon's-eye view). The blinded surgical trajectory was discerned by the virtual image through the opposite direction projected from above (bird's-eye view). The 3-D visualization of the nerve-vessel relationship with fusion images was consistent with the intraoperative trajectory and findings. CONCLUSION Fusion imaging of 3-D magnetic resonance cisternogram and MRA may prove a useful adjunct for the diagnosis and decision-making process to execute the microvascular decompression in patients with idiopathic trigeminal neuralgia.

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Pathophysiology of trigeminal neuralgia: new evidence from a trigeminal ganglion intraoperative microneurographic recording

Journal of Neurosurgery ◽

10.3171/jns.2004.101.5.0872 ◽

2004 ◽

Vol 101 (5) ◽

pp. 872-873 ◽

Cited By ~ 23

Author(s):

Kim J. Burchiel ◽

Thomas K. Baumann

Keyword(s):

Trigeminal Neuralgia ◽

Trigeminal Ganglion ◽

Physiological Mechanism ◽

Vascular Compression ◽

Entry Zone ◽

Content Type ◽

Root Entry Zone ◽

Trigeminal Ganglion Neurons ◽

Ganglion Neurons ◽

New Evidence

✓ The origin of trigeminal neuralgia (TN) appears to be vascular compression of the trigeminal nerve at the root entry zone; however, the physiological mechanism of this disorder remains uncertain. The authors obtained intraoperative microneurographic recordings from trigeminal ganglion neurons in a patient with TN immediately before percutaneous radiofrequency-induced gangliolysis. Their findings are consistent with the idea that the pain of TN is generated, at least in part, by an abnormal discharge within the peripheral nervous system.

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