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

Neurosurgery ◽  
2006 ◽  
Vol 59 (2) ◽  
pp. 354-359 ◽  
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.

Microvascular relations of the trigeminal nerve

1980 ◽  
Vol 52 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Stephen J. Haines ◽  
Peter J. Jannetta ◽  
David S. Zorub
Keyword(s):  
Trigeminal Neuralgia ◽  
Trigeminal Nerve ◽  
Facial Pain ◽  
Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Venous Compression ◽  
Trigeminal Nerve Root ◽  
Trigeminal Nerves ◽  
Fine Print

✓ The vascular relationships of the trigeminal nerve root entry zone were examined bilaterally in 20 cadavers of individuals known to be free of facial pain. Fourteen of 40 nerves made contact with an artery, but only four of these showed evidence of compression or distortion of the nerve. In addition, the vascular relationships of 40 trigeminal nerves exposed surgically for treatment of trigeminal neuralgia were studied, and 31 nerves showed compression by adjacent arteries. Venous compression was seen in four of the cadaver nerves and in eight nerves from patients with trigeminal neuralgia. These data support the hypothesis that arterial compression of the trigeminal nerve is associated with trigeminal neuralgia.

scholarly journals Trigeminal Neuralgia associated with Wallenberg Syndrome, a case report

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.

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

2015 ◽  
Vol 123 (6) ◽  
pp. 1512-1518 ◽  
Author(s):  
Yifei Duan ◽  
Jennifer Sweet ◽  
Charles Munyon ◽  
Jonathan Miller
Keyword(s):  
Trigeminal Neuralgia ◽  
Trigeminal Nerve ◽  
Microvascular Decompression ◽  
Cross Sectional Area ◽  
Vascular Compression ◽  
Sectional Area ◽  
Cross Sectional ◽  
Entry Zone ◽  
Root Entry Zone ◽  
Distal Nerve

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.

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

2004 ◽  
Vol 101 (5) ◽  
pp. 872-873 ◽  
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.

Analysis of morphological measurements of the trigeminal nerve in the linac stereotactic radiosurgery simulation targeting the root entry zone in trigeminal neuralgia

Neurocirugía ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 105-114
Author(s):  
Rafael Medélez-Borbonio ◽  
Alexander Perdomo-Pantoja ◽  
Alejandro Apolinar Serrano-Rubio ◽  
Colson Tomberlin ◽  
Rogelio Revuelta-Gutiérrez ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Stereotactic Radiosurgery ◽  
Trigeminal Nerve ◽  
Entry Zone ◽  
Root Entry Zone

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%.

VARIANT INTRANEURAL VEIN-TRIGEMINAL NERVE RELATIONSHIPS

Neurosurgery ◽  
2009 ◽  
Vol 65 (5) ◽  
pp. 958-961 ◽  
Author(s):  
Gregory M. Helbig ◽  
James D. Callahan ◽  
Aaron A. Cohen-Gadol
Keyword(s):  
Trigeminal Neuralgia ◽  
Trigeminal Nerve ◽  
Complication Rates ◽  
Entry Zone ◽  
Root Entry Zone ◽  
Detailed Classification ◽  
Trigeminal Nerve Root

Abstract OBJECTIVE Trigeminal neuralgia is often caused by compression, demyelination, and injury of the trigeminal nerve root entry zone by an adjacent artery and/or vein. Previously described variations of the nerve-vessel relationship note external nerve compression. We offer a detailed classification of intraneural vessels that travel through the trigeminal nerve and safe, effective surgical management. CLINICAL PRESENTATION We report 3 microvascular decompression operations for medically refractory trigeminal neuralgia during which the surgeon encountered a vein crossing through the trigeminal nerve. Two types of intraneural veins are described: type 1, in which the vein travels between the motor and sensory branches of the trigeminal nerve (1 patient), and type 2, in which the vein bisects the sensory branch (portio major) (2 patients). INTERVENTION We recommend sacrificing the intraneural vein between the motor and sensory branches if the vein is small (most likely type 1). If the intraneural vein is large and bisects the sensory branch (most likely type 2), vein mobilization can be achieved, but often requires extensive dissection through the nerve. Because this maneuver may lead to trigeminal nerve injury and result in uncomfortable neuropathy and numbness (including corneal hypoesthesia), we recommend against mobilization of the vein through the nerve, suggesting instead, consideration of a selective trigeminal nerve rhizotomy. CONCLUSION Because aggressive dissection of intraneural vessels can lead to higher than normal complication rates, preoperative knowledge of vein-trigeminal nerve variants is crucial for intraoperative success.

scholarly journals Automated Segmentation of Trigeminal Nerve and Cerebrovasculature in MR-Angiography Images by Deep Learning

2021 ◽  
Vol 15 ◽  
Author(s):  
Jinghui Lin ◽  
Lei Mou ◽  
Qifeng Yan ◽  
Shaodong Ma ◽  
Xingyu Yue ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Trigeminal Nerve ◽  
Three Dimensional ◽  
Dice Similarity Coefficient ◽  
Tissue Segmentation ◽  
Anatomical Structures ◽  
Entry Zone ◽  
Root Entry Zone ◽  
Automated Method ◽  
Neurosurgical Treatment

Trigeminal neuralgia caused by paroxysmal and severe pain in the distribution of the trigeminal nerve is a rare chronic pain disorder. It is generally accepted that compression of the trigeminal root entry zone by vascular structures is the major cause of primary trigeminal neuralgia, and vascular decompression is the prior choice in neurosurgical treatment. Therefore, accurate preoperative modeling/segmentation/visualization of trigeminal nerve and its surrounding cerebrovascular is important to surgical planning. In this paper, we propose an automated method to segment trigeminal nerve and its surrounding cerebrovascular in the root entry zone, and to further reconstruct and visual these anatomical structures in three-dimensional (3D) Magnetic Resonance Angiography (MRA). The proposed method contains a two-stage neural network. Firstly, a preliminary confidence map of different anatomical structures is produced by a coarse segmentation stage. Secondly, a refinement segmentation stage is proposed to refine and optimize the coarse segmentation map. To model the spatial and morphological relationship between trigeminal nerve and cerebrovascular structures, the proposed network detects the trigeminal nerve, cerebrovasculature, and brainstem simultaneously. The method has been evaluated on a dataset including 50 MRA volumes, and the experimental results show the state-of-the-art performance of the proposed method with an average Dice similarity coefficient, Hausdorff distance, and average surface distance error of 0.8645, 0.2414, and 0.4296 on multi-tissue segmentation, respectively.

Vascular Transposition of the Superior Cerebellar Artery Using a Fenestrated Clip and Fibrin Glue in Trigeminal Neuralgia: 2-Dimensional Operative Video

2019 ◽  
Vol 19 (1) ◽  
pp. E50-E51 ◽  
Author(s):  
Karl R Abi-Aad ◽  
Evelyn Turcotte ◽  
Devi P Patra ◽  
Matthew E Welz ◽  
Tanmoy Maiti ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Fibrin Glue ◽  
Trigeminal Nerve ◽  
Facial Pain ◽  
Superior Cerebellar Artery ◽  
Entry Zone ◽  
Root Entry Zone ◽  
Cerebellar Artery ◽  
Trigeminal Nerve Root ◽  
Made In

Abstract This is the case of an 86-yr-old gentleman who presented with left facial pain exacerbated by eating, drinking, chewing, and shaving (distribution: V2, V3). The patient was diagnosed with trigeminal neuralgia and was refractory to medications. Imaging showed a superior cerebellar artery (SCA) loop adjacent to the trigeminal nerve root entry zone and a decision to perform a microvascular decompression of the fifth nerve was presented to the patient. After patient informed consent was obtained, a standard 3 cm × 3 cm retrosigmoid craniotomy was performed with the patient in a supine head turned position and in reverse Trendelenburg. The arachnoid bands tethering the SCA to the trigeminal nerve were sharply divided. A slit was then made in the tentorium and a 3 mm fenestrated clip was then used to secure the transposed SCA away from the trigeminal nerve. The SCA proximal to this was slightly patulous in its course so a small amount of a fibrin glue was also used to secure the more proximal SCA to the tentorium. The patient was symptom-free postoperatively and no longer required medical therapy. Additionally, imaging was consistent with adequate separation of the nerve from adjacent vessels.1-5

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