Recommended
More Related Content
Similar to Neurovascular compression syndromes.pptx
Similar to Neurovascular compression syndromes.pptx (20)
Recently uploaded
Recently uploaded (20)
Neurovascular compression syndromes.pptx
- 1. Neurovascular Compression syndromes Presented by Dr.Leena(JRII) 12-10-2023
- 2. Contents • Introduction • Trigeminal nerve • Facial nerve • Glossopharyngeal nerve • Vestibulococlear nerve • Summary
- 3. Introduction • NVC - Direct contact with mechanical irritation of cranial nerves (CNs) by blood vessels. • Most common: trigeminal neuralgia (TN) hemifacial spasm (HFS) vestibulocochlear neuralgia glossopharyngeal neuralgia.
- 4. • REZ - cisternal part of nerve close to entrance into the pons • TZ - between central and peripheral myelinis - mechanical vulnerability. •CN V: 4 mm from root entry zone •CN VII: 2 mm from root entry zone •CN VIII: 10 mm from root entry zone •CN IX: 1.5 mm from root entry zone
- 6. Grading Vascular Compression • Grade I indicates simple contact between nerve and vessel • Grade II describes an artery displacing and/or distorting the nerve root • Grade III - thinning of the nerve root • Compressive vessels should - run at right angles to the nerve - contact at the root exit zone, and - deform it were useful for differentiation between substantial and nonsubstantial compression.
- 7. Brain stem Cistern Meckel cave and cavernous sinus Extracranial Trigeminal Nerve (CN V)
- 8. • 3 branches: ophthalmic (V1) maxillary (V2) mandibular (V3) • Distal to the Gasserian ganglion • transmits the sensory information to the brain stem via the cisternal portion (8 - 15 mm in length) • zone with central myelin (distance from brain stem to the TZ) is shorter on the medial side of the nerve (1.13 mm) than on its lateral side (2.47 mm).
- 9. • In the prepontine cistern, the sensory and motor divisions have a parallel but separate course, creating a characteristic fan-like appearance
- 10. ETIOLOGY: • most often caused by contact with the superior cerebellar artery (SCA) (88% ) • less frequently the anterior inferior cerebellar artery (AICA), or smaller branches of the basilar artery - superomedial portion (60%) • small cerebellopontine angle cistern appears to predispose to NVCS. • C/F : The pain is triggered by mild stimulation of a small area of the face (“trigger zone”) by everyday activities
- 14. Facial nerve • The facial and vestibulocochlear nerves have similar cisternal and canalicular courses • They both emerge from the lateral aspect of the lower border of the pons • traverse the cerebellopontine angle cistern at an oblique angle. (close proximity to the anterior inferior cerebellar artery) • cross the porus acusticus • traverse the length of the internal auditory canal.
- 15. Facial Nerve (CN VII) • Length of the cisternal segment (14.8–20.9 mm) • TZ was described at 1.9 mm from the nerve entry/exit - one-tenth of its cisternal length • The AICA (43%) is the most common vessel causing NVC/posterior inferior cerebellar artery (31%) and vertebral artery (23%). • Attrition of the neurovascular interface yields action potentials from the demyelinated facial nerves and causes HFS symptoms.
- 16. Hemifacial spasm • Symptom complex of hyperactive dysfunction of a unilateral facial nerve. • Caracterized by - onset of mild and intermittent spasms in the orbicularis oculi muscle that gradually progress in severity and frequency and spread downward to include all the muscles of facial ex- pression including the platysma . • Symptomatic ringing in the ears caused by stapedius muscle involvement. • Posterior inferior cerebellar artery/ anterior inferior cerebellar artery (PICA/AICA) - main causes of HFS.
- 19. Vestibulocochlear Nerve (CN VIII) • CN VIII is a sensory nerve carrying information from the spiral auditory organ (cochlear nerve) and the labyrinth (vestibular nerve) to the brain stem. • Composed of 3 parts: the cochlear nerve and the superior and inferior vestibular nerves. - 2 vestibular nerves join to become 1 nerve before their exit from the internal acoustic meatus. -The vestibular and cochlear nerves fuse to form the 8th CN closer to brain stem • It has a long cisternal segment - extends from the brain stem to the internal acoustic meatus (total distance = 14.2–19.2 mm) • The distance of the most distal part of the TZ from the brain stem - 9.28–13.84 mm
- 20. • In most cases (75%), the AICA is the compressing vessel. • vertigo - rostroventral nerve (vestibular nerve). • Tinnitus - compression of the caudal surface (cochlear nerve) of the nerve Vestibular Paroxysmia
- 21. • The types of neurovascular contact: (a) Type I - no neurovascular contact (b) Type II - neurovascular contact between AICA and cochleovestibular nerve without angulation/indentation of the nerve (c) Type III - Angulation/indentation of cochleovestibular nerve by AICA loop -
- 22. • AICA loop refers to an aberrant course of the anterior inferior cerebellar artery (AICA) that enters the internal auditory meatus and loops over the 7th and 8th cranial nerves. Chavda classification of AICA loops : • type I: lying only in the cerebellopontine angle (CPA), but not entering the internal auditory canal (IAC) • type II: entering, but not extending >50% of the length of the IAC • type III: entering and extending >50% of the length of the IAC Types of AICA loop
- 23. Glossopharyngeal nerve • The glossopharyngeal nerve emerges from the lateral medulla into the lateral cerebellomedullary cistern • Above the vagus nerve and at the level of the facial nerve. • In the lateral cerebellomedullary cistern, the glossopharyngeal nerve is closely associated with the flocculus of the cerebellum
- 24. Glossopharyngeal Nerve (CN IX) • Exits as 3–5 rootlets - later unite to form the cisternal CN IX. • The length of CN IX from the medulla oblongata to the jugular foramen varies between 14.2 and 19.9 mm. • TZ is located at 1.51 ± 0.39 mm - has a typical cone shape • Glossopharyngeal neuralgia : severe paroxysmal episodes of pain localized in the posterior tongue, tonsil, throat, or external ear canal • GN is caused by NVC, while in a minority of cases, trauma, neoplasms, infection, or an elongated styloid process (Eagle syndrome)
- 25. The posterior inferior cerebellar artery and, less frequently, the AICA are responsible for nerve compression
- 26. Summary
- 28. References ... • Parihar PH, Mishra GV, Shetty ND, Bora N, Bhagyasri N. Neurovascular compression syndromes: A pictorial essay. J Datta Meghe Inst Med Sci Univ 2023;18:286-90. • Donahue JH, Ornan DA, Mukherjee S. Imaging of Vascular Compression Syndromes. Radiol Clin North Am. 2017 Jan;55(1):123-138. doi: 10.1016/j.rcl.2016.08.001. PMID: 27890181. • Yoshino N, Akimoto H, Yamada I, Nagaoka T, Tetsumura A, Kurabayashi T, et al. Trigeminal neuralgia: evaluation of neuralgic manifestation and site of neurovascular compression with 3D CISS MR imaging and MR angiography. Radiology 2003;228(2):539—45 [Epub 2003 Jun 11]. • Serap Gültekin, H. Hamdi Çelik, Sergin Akpek, Y. Öner, Tülin Gümüş, Nil Tokgöz. Vascular Loops at the Cerebellopontine Angle: Is There a Correlation with Tinnitus? American Journal of Neuroradiology. 2008 Oct 1;29(9):1746–9.
- 29. Thank you...
Editor's Notes
- Redlich–Obersteiner's zone.CN VIII having a long and distal TZ in comparison with CNs V, VII, and IX. Oligodendrocytes form the myelin in the central nervous system, whereas Schwann cells form the myelin in the peripheral nervous system. REZ” is used to define the portion of the nerve that includes the TZ, the central myelin root portion, and the adjacent brain stem surface
- The criteria tha the
- m this area of the pons, the mesencepha_x0002_lic nucleus projects cephalad to the level of the inferior COlliCl.llLis, and the spinal nucleus cx_x0002_Nerve can be divided into four segments.ultiple sclerosis, infarct, and glioma are the most common abnormalities in the brain stem leading to trigeminal neuropathy. nds caudad to the level of the second cervical vertebra. ranial nerve V enters the Meckel cave through an opening in the dura mater, the pOnis trigeminus (entrance to the Meckel cave). The nerve carries its dural covering with it into the Meckel cave. The leptomeninges also follow the nerve, resulting in a cerehrospinal fluid-filled subarachnoid space-the trigeminal cistern-which surrounds the nerve within the Meckel cave
- The trigeminal nerve originates from two separate nuclei in the pons: the sensory division from the sensory nucleus and the motor division from the motor nucleus . This first part is called the brain stem segment.From these nuclei, the trigeminal nerve courses anteriorly, to the ventrolateral surface of the pons to continue with the cisternal segment in the prepontine cistern.The trigeminal nerve is the largest of all cranial nerves.The sensory division – which is the largest of the two – innervates sensibility in the whole face.The smaller motor division innervates: masticator muscle temporalis muscle pterygoid muscles mylohyoid muscle anterior belly of the digastric muscle, tensor veli palatine muscle tensor tympani muscle
- Axial steady-state free precession image shows trigeminal nerve anatomy. Porus trigeminus is visualized anteriorly (arrows) and root entry point is marked (arrowhead). Yellow line approximates most anterior location that transition between proximal centrally myelinated portion (posteriorly) and distal peripherally myelinated portion (anteriorly) occurs. however, other etiologies, such as neoplastic, inflammatory, and infectious conditions or trauma, may exist as well. Less often, CN V is compressed by the basilar and vertebral arteries,15,16 by a saccular aneurysm, a persistent trigeminal artery, an arteriovenous malformation or a petrous vein Root entry zone
- Schematic demonstrates the classification of the position of a blood vessel that compresses the trigeminal nerve on its cross section. When the blood vessel has compressed the trigeminal nerve at the position shown in this schematic, it is classified as a medial site. Schematic of the trigeminal nerve fiber array at the REZ. The nerve fibers of the second branch (V2) are widely distributed medially, those of the third branch (V3) are widely distributed laterally, and those of the first branch (V1) are distributed cranially. transverse 3D CISS MR images (12.25/5.9, 70° flip angle) show that the superior cerebellar artery (short arrow) has compressed the REZ of the right trigeminal nerve (long arrow) at the medial site. lateral - v3, medial v2, medial cranial and caudal v2, lateral caudal v3.. medial cranial V1 AND V2
- , Axial steady-state free precession (SSFP) image shows bifurcated right superior cerebellar artery (SCA; arrows) contacting and deforming right trigeminal nerve (arrowhead). Note resultant deformity along medial surface of nerve. B, Sagittal SSFP image shows SCA branches (arrows) contacting trigeminal nerve.
- Axial 0.8-mm-thick SSFP MR image shows the parallel courses of the facial (black arrowheads) and superior vestibular (white arrowheads) nerves as they cross the cerebellopontine angle to enter the internal auditory canal through the porus acusticus (double arrow).cross the porus acusticus (an opening between the cerebellopontine angle cistern and the internal auditory canal; also known as the internal acoustic meatus) Sagittal oblique 1.0-mm-thick SSFP images, obtained in planes perpendicular to the left (a) internal auditory canal:facial (white arrow), superior vestibular (white arrowhead), and inferior vestibular (black arrowhead) nerves are depicted;the cochlear nerve (black arrow in a)
- CN VII is a mixed nerve, which essentially controls the muscles of facial expression, transmits taste sensations from the anterior two-thirds of the tongue, and supplies parasympathetic fibers to the nasal mucosa, submandibular, sublingual, and lacrimal glands.
- vessels that cross the peripheral portion of the facial nerve /run parallel to the nerve also do not cause hemifacial spasms vessels that cross the peripheral portion of the facial nerve /run parallel to the nerve also do not cause hemifacial spasms ight vertebral artery extends into the right cerebellopontine angle (large arrow in b and c) and, together with the PICA (arrowhead in a and c), compresses the root exit zone of the facial nerve .Small arrow in b and c = facial nerve, open arrow in c = vestibuloco-
- Right HFS caused by an AICA loop in a 60-year-old man. Fusion of 3D T2 and TOF angiography sequences (0.6-mm thin sections; A, axial; B and C, coronal sections). Axial oblique reformatted T2-weighted image along the cisternal CN VII (D). Coronal oblique reformatted contrast-enhanced T1-weighted image (E). Note contact between an AICA loop and the presumed TZ of CN VII (white arrows), which is slightly indented. There is a second contact between the AICA and the more distal CN VII (arrowheads). Black arrows point to CN VII. NVCS due to the AICA loop impinging on the TZ was confirmed surgically. After the operation, symptoms disappeared
- HFS caused by a posterior inferior cerebellar artery (PICA) loop in a 54-year-old man. Axial oblique (A) and coronal oblique (B) reformatted images obtained by fusion of CISS (0.6 mm) and TOF angiography sequences show NVC of CN VII (arrows, A and B) by the PICA at the presumed TZ (arrowhead). 3D MIP reconstruction of the TOF sequence (C) shows a PICA loop on the right, responsible for HFS. Findings were confirmed surgically.
- Axial (a) 3D FIESTA
- Axial (a) 3D FIESTA
- The flocculus is a lobule of cerebellar tissue that is directly adjacent to the glossopharyngeal nerve, and it should not be mistaken for an abnormality.Coronal oblique 0.8-mm-thick SSFP MR image through the cerebellopontine angle shows the glossopharyngeal nerve (arrow) just beneath the flocculus (f) of the cerebellum. The two roots of the vagus nerve (arrowheads) are visible in the same plane, and the superior and inferior vestibular nerves can be seen above the flocculus.
- CN IX is a mixed sensory, motor, and parasympathetic nerve. Sensory information comes from the posterior tongue and oropharyngeal and ear region, while chemo- and baroreceptor input comes from the carotid body and carotid sinuses. The motor component supplies the stylopharyngeal muscle and the secretomotor fibers of the ipsilateral parotid gland. Tympanic nerve (AKA nerve of Jacobson) – carries parasympathetic fibers and eventually becomes the lesser petrosal nerve, exiting the skull via the foramen ovale and synapses in the otic ganglion Stylopharyngeal nerve – provides motor innervation to the stylopharyngeus muscle The nerve to carotid sinus – communicates with the vagus nerve to carry signals from the baroreceptors in the carotid sinus and chemoreceptors in the carotid body - this helps in regulating blood pressure (carotid sinus) and monitoring blood oxygen and CO2 levels (carotid body) Pharyngeal branches – join with the pharyngeal branches of the vagus nerve and sympathetic nerves to form the pharyngeal plexus, which innervates the muscles of the pharynx Tonsillar branches – provides sensory innervation to the palatine tonsil Lingual branches – supply the vallate papillae, mucous membrane, and follicular glands of the posterior tongue
- GN caused by a tortuous vertebral artery in a 64-year-old man. Axial T2-weighted (A), fused T2-weighted and TOF (B) images, and contrast-enhanced 3D T1 gradient recalled-echo image (C) show displacement and contact between CN IX (long arrows) and a tortuous vertebral artery (short arrows). Note that in B, 2 contact points are seen, 1 proximal and 1 more distal. Black arrows point to the contralateral IX–X nerve complex Left invalidating GN caused by a posterior inferior cerebellar artery (PICA) loop in an 80-year-old otherwise healthy female patient. Fusion of 3D T2 and TOF angiography sequences (A, axial; B, coronal oblique) reveals displacement of CN IX (white arrows) and contact between the TZ of CN IX and the left PICA (arrowheads). Right CN IX is indicated by a black arrowhead.
- Glossopharyngeal nerve palsy occurs as a part of the following stroke syndromes: Vernet syndrome (affecting IX, X, XI)[11] Collet-Sicard syndrome (affecting IX, X, XI, XII) Villaret syndrome (affecting IX, X, XI, XII, and sympathetic fibers) TZ length and location vary between cranial nerves (Fig 12). While the TZ is close to the brain stem and overlaps the REZ in CN V, VII, and IX, it is longer, located more distally, and does not overlap the REZ in CN VIII.9 Although symptomatic NVCS can occur outside the TZ, most NVCSs are seen at the TZ.
- MVD, microvascular decompression