Neurovascular relationships of the root entry zone of lower cranial nerves: A microsurgical anatomic study in fresh cadavers

A patient with trigeminal neuralgia secondary to a vestibular schwannoma underwent fractionated radiotherapy without relief of her pain. She was then effectively treated with microsurgical resection of her tumor. Early identification of the lower cranial nerves and the origin of the facial and vestibulocochlear nerves is key to determining the operative corridors for vestibular schwannoma resection. To effectively treat trigeminal neuralgia, the trigeminal nerve root entry zone and motor branch are clearly identified and decompressed. Fractioned radiotherapy does not effectively treat trigeminal neuralgia secondary to vestibular schwannoma compression. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID21112

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Ophthalmoplegic migraine: From questions to answers

Cephalalgia ◽

10.1177/0333102414523843 ◽

2014 ◽

Vol 34 (11) ◽

pp. 914-919 ◽

Cited By ~ 16

Author(s):

Paolo Ambrosetto ◽

Francesca Nicolini ◽

Matteo Zoli ◽

Luigi Cirillo ◽

Paola Feraco ◽

...

Keyword(s):

Magnetic Resonance ◽

Facial Pain ◽

Cranial Nerves ◽

Imaging Findings ◽

Headache Disorders ◽

Entry Zone ◽

Root Entry Zone ◽

Ophthalmoplegic Migraine ◽

Cranial Neuralgias

Introduction The International Classification of Headache Disorders classifies ophthalmoplegic migraine (OM) under “cranial neuralgias and central causes of facial pain.” OM is diagnosed when all the following criteria are satisfied: At least two attacks fulfilling criterion B. Migraine-like headache accompanied or followed within four days of its onset by paresis of one or more of the III, IV and/or VI cranial nerves. Parasellar orbital fissure and posterior fossa lesions ruled out by appropriate investigations. In children the syndrome is rare and magnetic resonance (MR) shows strongly enhancing thickened nerve at the root entry zone (REZ). Method The authors review the literature focusing on pathogenesis theories. Results The authors suggest that ischemic reversible breakdown of the blood-nerve barrier is the most probable cause of OM and to include MR findings in the hallmarks of the disease. Conclusion OM is the same disease in adulthood and childhood, even if in adults the MR imaging findings are negative. In the authors’ opinion, OM should be classified as migraine.

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Glossopharyngeal neuralgia

Journal of Neurosurgery ◽

10.3171/jns.1977.47.3.0316 ◽

1977 ◽

Vol 47 (3) ◽

pp. 316-320 ◽

Cited By ~ 143

Author(s):

Ranjit K. Laha ◽

Peter J. Jannetta

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Cranial Nerves ◽

Glossopharyngeal Neuralgia ◽

Vascular Compression ◽

Entry Zone ◽

Content Type ◽

Root Entry Zone ◽

Cerebellar Artery ◽

Sporadic Cases ◽

Fine Print

✓ Various factors have been considered in the etiology and pathogenesis of glossopharyngeal neuralgia. Vascular compression of the involved cranial nerves has been demonstrated in sporadic cases. In this series of six patients, it was noted with the aid of the operating microscope that the ninth and tenth cranial nerves were compressed by a tortuous vertebral artery or posterior inferior cerebellar artery at the nerve root entry zone in five cases. In selected patients, microvascular decompression without section of the nerves may result in a cure.

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Postherpetic Neuralgia of the Trigeminal Nerve (Trigeminal Tractotomy-Nucleotomy)

Pain Neurosurgery ◽

10.1093/med/9780190887674.003.0017 ◽

2019 ◽

pp. 131-140

Author(s):

Zoe Teton ◽

Ahmed M. Raslan

Keyword(s):

Pain Relief ◽

Adverse Effects ◽

Dorsal Root ◽

Cranial Nerves ◽

Spinal Trigeminal Nucleus ◽

Trigeminal Nucleus ◽

Entry Zone ◽

Dorsal Root Entry Zone ◽

Root Entry Zone ◽

Hospital Stays

Trigeminal tractotomy-nucleotomy (TR-NC) is an effective operation in conditions where peripheral ablation would not be effective or when pain is due to involvement of multiple cranial nerves. Lesioning of the entire nucleus caudalis at the dorsal root entry zone (DREZ) represents a more extensive version of TR-NC. Here the focus is on the less invasive, percutaneous TR-NC or “mini-caudalis DREZ”. The target of TR-NC is the lateral descending trigeminal tract and nucleus caudalis of the spinal trigeminal nucleus. In select patient populations, careful lesion creation can be highly effective in providing immediate and long-lasting pain relief, with minimal adverse effects, lower cost and shorter hospital stays.

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Lower Skull Base: Anatomic Study with Surgical Implications

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348949510400109 ◽

1995 ◽

Vol 104 (1) ◽

pp. 57-61 ◽

Cited By ~ 30

Author(s):

Essam Saleh ◽

Maged Naguib ◽

Yasar Cokkeser ◽

Miguel Aristegui ◽

Mario Sanna

Keyword(s):

Connective Tissue ◽

Skull Base ◽

Fibrous Tissue ◽

Cranial Nerves ◽

Jugular Foramen ◽

Jugular Bulb ◽

Microsurgical Anatomy ◽

Anatomic Study ◽

Hypoglossal Canal ◽

Lower Cranial Nerves

With advances in the lateral approaches to the skull base and the increasing success of the management of jugular foramen lesions, a thorough knowledge of the anatomy of this region is needed. The purpose of the present work is to study the detailed microsurgical anatomy of the lower skull base and the jugular foramen area as seen through the lateral approaches. Forty preserved skull base specimens and 5 fresh cadavers were dissected. The shape of the jugular bulb and its relationship to nearby structures were recorded. The different venous connections of the bulb were noted. The hypoglossal canal was identified and its contents were observed. The lower cranial nerves were studied at the level of the upper neck, at their exit from the inferior skull base, and in the jugular foramen. The results of the present study showed the complex and variable anatomy of this area. The classic compartments of the jugular foramen were not always present. Cranial nerves IX through XI followed different patterns while passing through the jugular foramen, being separated from the jugular bulb by bone, thick fibrous tissue, or thin connective tissue.

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Endoscope Assisted Microvascular Decompression: Are the Advantages Still Worthy Towards More?

Egyptian Journal of Neurosurgery ◽

10.1186/s41984-019-0072-5 ◽

2020 ◽

Vol 35 (1) ◽

Author(s):

Ashraf Mohamed Farid ◽

Sherif Elsayed ElKheshin

Keyword(s):

Microvascular Decompression ◽

Cranial Nerves ◽

Case Series ◽

Definitive Treatment ◽

Vascular Structure ◽

Panoramic View ◽

Entry Zone ◽

Root Entry Zone ◽

Cerebellar Retraction ◽

Vascular Structures

Abstract Background Microvascular decompression is the definitive treatment of various neuralgias affecting cranial nerves. The compression on a cranial nerve could be at the root entry zone, especially the trigeminal nerve. Endoscope-assisted microsurgery may help avoid missing a hidden vascular structure. Study design Retrospective clinical case series. Patient and methods Twenty-five patients with facial pain and five patients with hemifacial spasm constituted this study. FIESTA MRI was the pre-operative neuroimaging modality. Retrosegmoid craniectomy was done for all patients. Microscope was initially used for exploration and arachnoid dissection around the nerve. The endoscope was applied thereafter for exploration and confirmation of the proper insertion of the Teflon. Results Using the endoscope, cerebellar retraction was reduced by 0.5 to 0.8 cm in 90% of patients. Root entry zone and entry of the nerve through the corresponding skull base foramen was clearly visualized by the endoscope. Endoscope enabled a wider area of exploration and panoramic view, which could not be obtained by the microscope. Patients with trigeminal neuralgia had a median pre-operative VAS of 9, while it was only 1 in early post-operative and 0 in 6-month post-operatively. Patients with HFS were completely recovered. Conclusion The advantages of microvascular decompression are still worthy. Complications are minimal, and the view is much more panoramic. The different viewing angles and ability to directly reach corners is an absolute endoscopic advantage. Therefore, avoidance of missing vascular structures and incomplete recovery can be assured.

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Retrosigmoid Suprafloccular Transhorizontal Fissure Approach for Resection of Brainstem Cavernous Malformation

Operative Neurosurgery ◽

10.1227/01.neu.0000369703.67562.bb ◽

2010 ◽

Vol 66 (suppl_2) ◽

pp. ons306-ons313 ◽

Cited By ~ 4

Author(s):

Shiro Ohue ◽

Takanori Fukushima ◽

Allan H. Friedman ◽

Yoshiaki Kumon ◽

Takanori Ohnishi

Keyword(s):

Neurological Status ◽

Early Postoperative Period ◽

Neurological Deficits ◽

Anatomic Study ◽

Cavernous Malformations ◽

Entry Zone ◽

Root Entry Zone ◽

Microsurgical Resection ◽

Cerebellar Peduncle

Abstract OBJECTIVE This study examined the usefulness of a surgical approach (retrosigmoid suprafloccular transhorizontal fissure approach) for resection of brainstem cavernous malformations (CMs). METHODS An anatomic study concerning the retrosigmoid suprafloccular transhorizontal fissure approach was performed with 3 cadaveric heads. Clinical course was retrospectively reviewed for 10 patients who underwent microsurgical resection of brainstem CMs with this approach. Medical, surgical, and neuroimaging records of these patients were evaluated. RESULTS In the anatomic study, after standard suboccipital retrosigmoid craniotomy, the horizontal fissure on the petrosal surface of the cerebellum was dissected between the superior semilunar lobule and flocculus. With this approach, the root entry zone of the trigeminal nerve and the middle cerebellar peduncle could be exposed by superior retraction of the superior semilunar lobule. The lateral surface of the pons was then easily visible around the root entry zone. When this approach was used for 10 brainstem CMs, complete resection was achieved in 9 patients (90%). No mortality was encountered in this study. New neurological deficits occurred in the early postoperative period for 4 patients but were transient in 3 patients. Neurological status at final follow-up was improved in 4 patients (40%), unchanged in 5 patients (50%), and worse in 1 patient (10%) compared with preoperative conditions. CONCLUSION The retrosigmoid suprafloccular transhorizontal fissure approach is useful for the resection of lateral pontine CMs.

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Tic convulsif: results in 11 cases treated with microvascular decompression of the fifth and seventh cranial nerves

Journal of Neurosurgery ◽

10.3171/jns.1984.61.5.0949 ◽

1984 ◽

Vol 61 (5) ◽

pp. 949-951 ◽

Cited By ~ 44

Author(s):

Bruce R. Cook ◽

Peter J. Jannetta

Keyword(s):

Microvascular Decompression ◽

World Literature ◽

Cranial Nerves ◽

Anterior Inferior Cerebellar Artery ◽

Vascular Compression ◽

Entry Zone ◽

Content Type ◽

Vascular Abnormalities ◽

Root Entry Zone ◽

The Individual

✓ The syndrome of tic convulsif consists of ipsilateral concurrent trigeminal neuralgia and hemifacial spasm. Since Cushing's 1920 description of this syndrome in three patients, 37 additional cases have been reported in the world literature. Of the 15 with adequate operative descriptions, 10 had vascular abnormalities and five had tumors. The authors report 11 cases of tic convulsif treated by microvascular decompression of both the fifth and seventh cranial nerves. At operation, 21 of 22 nerves were found to have root entry zone vascular compression. One trigeminal nerve was considered normal. One seventh nerve had a tumor displacing the anterior inferior cerebellar artery into its root entry zone. The average follow-up period in this series was 6 years 2 months (range 1 to 8½ years). Eight patients (73%) were pain-free, two (18%) had frank recurrences, and one (9%) had mild discomfort. Eight patients (73%) were totally free of facial spasm, and two others (18%) had only a trace of residual spasm. These results are comparable to those achieved by treating the individual syndromes with microvascular decompression. Therefore, microvascular decompression of both the fifth and seventh cranial nerves is recommended as the treatment of choice in tic convulsif.

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