Khrais / Sanna / Mancini The Facial Nerve in Temporal Bone and Lateral Skull Base Microsurgery

1. Auflage 2006
ISBN: 978-3-13-258138-8
Verlag: Thieme
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 312 Seiten, ePub

This lavishly illustrated atlas provides comprehensive coverage of the surgical management of facial nerve tumors and of the facial nerve in diseases affecting the temporal bone and lateral skull base. The surgical management and the different operative procedures involved are described step-by-step using full-color images of outstanding quality drawn from a collection of over 1700 cases of skull base surgery and 18000 case of middle ear surgery.

The expert authors discuss the management of the facial nerve in various pathologies, the facial nerve in petrous bone cholesteatoma, the management of the facial nerve in vestibular schwannomas and meningiomas, and facial nerve management in glomus tumors, middle ear carcinomas, and with cochlear implants.

Key features:

Opening chapters on facial nerve anatomy, radiology, operating room set-up, and intraoperative facial nerve monitoring, representing the knowledge needed before considering surgery
Chapters on facial nerve repair and reanimation, and comprehensive coverage of tumors of the facial nerve
Dr. Sanna is part of The Grupppo Otologico, a world-renowned specialist center for the diagnosis and medical and surgical treatment of diseases of the ear, skull base, facial nerve, head and neck, and paranasal sinuses. More information is available on the group's website, www.gruppootologico.it/eng.

Zielgruppe

Ärzte

Autoren/Hrsg.

Khrais, Tarek

Sanna, Mario

Mancini, Fernando

Taibah, Abdelkader

Russo, Alessandra

Fachgebiete

• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Chirurgie
• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Klinische und Innere Medizin HNO-Heilkunde, Phoniatrie, Audiologie

Inhaltsverzeichnis

1 Anatomy of the Facial Nerve
2 Facial Nerve Radiology
3 The Operating Room
4 Intraoperative Facial Nerve Monitoring
5 Facial Nerve Reanimation
6 Management of Facial Nerve Injuries
7 Tumors of the Facial Nerve
8 Facial Nerve Management in Vestibular Schwannoma Surgery
9 Facial Nerve Management in Meningioma Surgery
10 Facial Nerve Management in Tympanic and Tympanojugular Paragangliomas
11 Facial Nerve Management in Petrous Bone Cholesteatoma Surgery
12 Facial Nerve Management in Middle Ear and External Auditory Canal Carcinoma
13 Facial Nerve Management in Cochlear Implant Surgery

Leseproben

1 Anatomy of the Facial Nerve
Anatomy of the Intracranial Facial Nerve
The facial nerve (seventh cranial nerve, CN VII) is a mixed nerve containing motor, sensory, and parasympathetic fibers. The motor component forms the major part of the nerve and receives contributions from three sources. Fibers originating in the lower part of the precentral gyrus of the cortex pass down to reach the posterior portion of the internal capsule, where they are tightly packed together. From there, they pass in proximity to the pyramidal tract in the basal part of the pons, where the majority of fibers cross to the contralateral facial nucleus. Only a small proportion of the fibers innervating the occipitofrontalis and the orbicularis oculi muscles contribute to the ipsilateral facial nucleus. From the thalamus and globus pallidus, fibers concerned with emotional facial expressions reach the nerve via the reticular formation. The last group of neurons contributing to the motor component of the facial nerve are derived from the central brainstem nuclei. The neurons of this group are concerned with the complex facial nerve reflexes and reach the facial nerve nucleus through the connections with the corresponding nucleus. The most important are the corneal reflex through the trigeminal nuclei and the stapedius reflex through acoustic nuclei. The second group of efferent fibers carried by the facial nerve are the visceral efferents. These fibers are concerned with the secretomotor function of the facial nerve and supply the submandibular, sublingual, and lacrimal glands, and the secretory glands of the pharynx, palate, and nose. They originate in the superior salivatory nucleus near the facial nucleus and reach the facial nerve after passing through the nervus intermedius. In addition to efferent fibers, the facial nerve embraces two types of afferents. Visceral afferents carry taste sensation from the anterior two-thirds of the tongue and from the soft palate. Somatic afferents carry sensation from the concha, from a small part of the external auditory meatus, and from a small spot of skin posterior to the auricle. Both afferents enter the brainstem after passing through the nervus intermedius. Thereafter, visceral afferents pass to the nucleus of the tractus solitarius, while somatic afferents pass to the trigeminal nuclei. After leaving the facial motor nucleus, neurons pass posterolaterally and turn around the nucleus of the sixth cranial nerve (abducent nerve, CN VI) to reach their exit from the brainstem. The course of the facial nerve after emerging from the brainstem is traditionally divided into three parts: intracranial, intratemporal, and extracranial. Numerous studies have reported the measurements of each portion of the facial nerve. In our practice we do not depend much on these measurements because of the relatively wide differences between individuals, preventing any significant predictive value, especially in delicate surgery such as that of the skull base. The intracranial part includes both the cerebellopontine angle (CPA) and the intracanalicular segments of the facial nerve. The CPA segment starts after the facial nerve leaves the pons ventrolaterally near its posterior border above the olive (Fig. 1.1). The nervus intermedius (Fig. 1.2) emerges at the lower border of the pons between the pons and the cerebellar peduncle lying closer to the origin of the vestibulocochlear nerve (CN VIII). The three nerves travel together in the pontine cistern in a lateral direction to reach the porus of the internal auditory canal (IAC) with the nervus intermedius lying in the middle all the way to the fundus. Near the brainstem, the facial nerve lies anterior and inferior to CN VIII. As they move laterally, the facial nerve gently curves superiorly to form an anterosuperior relation to CN VIII at the level of the porus. This relation is also maintained in the IAC (Fig. 1.3). A sleeve of meninges invests and is slightly adherent to the inner surface of the IAC. Near the fundus of the IAC the dura merges with the facial nerve and nervus intermedius, forming a single trunk. Fig. 1.1 The relationship between the intracranial segment of the facial nerve (FN) and the cochlear nerve (CN) after a translabyrinthine approach. Note the anterior inferior cerebellar artery (AICA) passing between the two nerves. Fig. 1.2 The relationship between the nervus intermedius (NI) and the facial nerve (FN) after the cochlear nerve has been cut. V, trigeminal nerve. Fig. 1.3 The contents of the opened internal auditory canal can be seen. F, facial nerve; SV, superior vestibular nerve. C, cochlear nerve; IV, inferior vestibular nerve; D, dura of the canal; HC, horizontal crest. Fig. 1.4 A hook is used to detach the superior ampullary nerve (SA) from its canal; the Bill’s bar (^) can be seen lying anterior to the hook protecting the labyrinthine segment of the facial nerve. HC, horizontal crest. Fig. 1.5 The view of the fundus after removal of the vestibular nerve. BB, Bill’s bar; FN, facial nerve in the internal auditory canal; >, the beginning of the labyrinthine segment of the facial nerve; HC, horizontal crest; CN, cochlear nerve; V, vestibule. Fig. 1.6 An endoscopic view of the fundus of a right internal auditory canal. Lying anterior to the Bill’s bar (B) the opening of the fallopian canal for the passage of the labyrinthine segment of the facial nerve (FN) can be seen. HC, horizontal crest; SVN, superior vestibular nerve; CN, cochlear nerve; IVN, inferior vestibular nerve; SN, singular nerve. At the lateral end of the internal auditory canal, the fundus forms the line of demarcation between the intradural and intratemporal parts of the nerve. The fundus is divided into three compartments by two bony bars (Figs. 1.4–1.6). The horizontal crest is a bar of bone that extends along the horizontal meridian of the fundus. From its center the vertical crest (Bill’s bar) extends to the superior border of the canal. The joint facial nerve passes through the anterosuperior compartment of the fundus to reach the intralabyrinthine canal. The superior vestibular nerve passes through the posterosuperior compartment to continue thereafter as the superior ampullary nerve. This nerve runs in a small canal that connects the posterosuperior compartment and the ampullae of the lateral and superior semicircular canals. Identification of the canal in translabyrinthine surgery acts as the best landmark to identify the facial nerve in the internal auditory canal. At this level, Bill’s bar protects the facial nerve lying anterior to it from being injured during dislodging of the ampullary nerve from its canal. Once the ampullary nerve is dislodged, it can be followed to its origin from the superior vestibular nerve. On dislocating the latter posteriorly from the internal auditory canal, the facial nerve can be seen lying anterior to it. Anatomy of the Intratemporal Facial Nerve
This part of the facial nerve is encased within a bony canal (fallopian canal). It is divided into three segments that are separated from each other by two genus (Figs. 1.7–1.10). Fig. 1.7 A view of the facial nerve from the middle cranial fossa. FN(t), tympanic segment of the facial nerve; M, head of the malleus; I, body of the incus; G, geniculate ganglion; L, labyrinthine segment of the facial nerve; BB, Bill’s bar; SVN, superior vestibular nerve; FN (iac), internal auditory canal segment of the facial nerve; GPN, greater superficial petrosal nerve; C, cochlea; AE, arcuate eminence; MFD, middle fossa dura. Fig. 1.8 The relationship of the facial nerve segments to the inner ear seen from a left middle cranial fossa. FN(g), facial nerve genu; FN(t), tympanic segment of the facial nerve; GG, geniculate ganglion; L, labyrinthine segment of the facial nerve; FN, internal auditory canal segment of the facial nerve; GPN, greater petrosal nerve; SV, superior vestibular nerve; *, Bill’s bar; C, cochlea; V, vestibule; SSC, superior semicircular canal; LSC, lateral semicircular canal; PSC, posterior semicircular canal; ET, eustachian tube; M, malleus; I, incus. Fig. 1.9 The relationship of the facial nerve to the inner ear seen from a left middle cranial fossa; in this case the labyrinth has been opened. T, tympanic segment of the facial nerve;...

Über Autor(innen)

Mario Sanna