The Brainstem & Cranial Nerves

Neuroanatomy ◽  
2017 ◽  
pp. 165-205
Author(s):  
Adam J Fisch
Keyword(s):  
Skull Base ◽  
Neurological Disorders ◽  
Cranial Nerves ◽  
Extraocular Muscles ◽  
Pharyngeal Arch

This chapter focuses on learning about the brainstem and cranial nerves—their components, function, and anatomy. The chapter provides instruction on how to draw the brainstem, the midbrain, the pons, the medulla, cranial nerves, the skull base, the somatomotor set, pharyngeal arch set, and solely sensory set. Also discussed are neurological disorders associated with the brainstem and cranial nerves and their mechanisms, and the mechanics of the extraocular muscles and their associated disorders.

Full tractography for detecting the position of cranial nerves in preoperative planning for skull base surgery: technical note

2020 ◽  
Vol 132 (5) ◽  
pp. 1642-1652 ◽  
Author(s):  
Timothee Jacquesson ◽  
Fang-Chang Yeh ◽  
Sandip Panesar ◽  
Jessica Barrios ◽  
Arnaud Attyé ◽  
...  
Keyword(s):  
Skull Base ◽  
Preoperative Planning ◽  
Skull Base Surgery ◽  
Cranial Nerves ◽  
Patient Specific ◽  
Small Scale ◽  
Skull Base Tumor ◽  
Skull Base Tumors ◽  
Brain White Matter ◽  
Human Connectome Project

OBJECTIVEDiffusion imaging tractography has allowed the in vivo description of brain white matter. One of its applications is preoperative planning for brain tumor resection. Due to a limited spatial and angular resolution, it is difficult for fiber tracking to delineate fiber crossing areas and small-scale structures, in particular brainstem tracts and cranial nerves. New methods are being developed but these involve extensive multistep tractography pipelines including the patient-specific design of multiple regions of interest (ROIs). The authors propose a new practical full tractography method that could be implemented in routine presurgical planning for skull base surgery.METHODSA Philips MRI machine provided diffusion-weighted and anatomical sequences for 2 healthy volunteers and 2 skull base tumor patients. Tractography of the full brainstem, the cerebellum, and cranial nerves was performed using the software DSI Studio, generalized-q-sampling reconstruction, orientation distribution function (ODF) of fibers, and a quantitative anisotropy–based generalized deterministic algorithm. No ROI or extensive manual filtering of spurious fibers was used. Tractography rendering was displayed in a tridimensional space with directional color code. This approach was also tested on diffusion data from the Human Connectome Project (HCP) database.RESULTSThe brainstem, the cerebellum, and the cisternal segments of most cranial nerves were depicted in all participants. In cases of skull base tumors, the tridimensional rendering permitted the visualization of the whole anatomical environment and cranial nerve displacement, thus helping the surgical strategy.CONCLUSIONSAs opposed to classical ROI-based methods, this novel full tractography approach could enable routine enhanced surgical planning or brain imaging for skull base tumors.

scholarly journals RARE-32. PEDIATRIC METASTATIC SKULL BASE CHORDOMA WITH TP53 MUTATION – A CASE REPORT AND REVIEW OF THE LITERATURE

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii449-iii449
Author(s):  
Akira Shimada ◽  
Kazuhiko Kurozumi ◽  
Kiichiro Kanamitsu ◽  
Hisashi Ishida Ishida ◽  
Kaori Fujiwara ◽  
...  
Keyword(s):  
Skull Base ◽  
Tp53 Mutation ◽  
Cranial Nerves ◽  
Gamma Knife Radiosurgery ◽  
Biological Behavior ◽  
Maximum Diameter ◽  
Cervical Lymph Nodes ◽  
First Choice ◽  
Systemic Metastasis ◽  
Skull Base Chordoma

Abstract Chordoma is an uncommon bone tumor arising from notochordal remnant, which accounts for 1–4% of all bone malignancies. It commonly occurs along the cranial-spinal axis, and skull base is one of most frequent sites, representing 35–49% of all chordoma cases. Surgical resection is widely accepted as the first choice of treatment. There are only limited number of reports about pediatric chordoma cases, and its biological behavior including genetic backgrounds were largely unknown. Here, we present a 5 year-old girl with a large aggressive skull base chordoma of 6 cm in maximum diameter, which eventually had multiple systemic metastasis. We initially tried chemotherapy based on the protocol for the osteosarcoma, but in vain. Because the tumor was highly vascularized on angiography, after embolization of the feeding arteries and bilateral internal maxillary arteries, endoscopic endonasal surgery was performed. The tumor was sufficiently removed, achieving effective mass reduction, and the residual tumors involving the lower cranial nerves and craniocervial junction were additionally treated with Gamma Knife radiosurgery. However, one month later, it showed systemic metastasis to bilateral cervical lymph nodes and lung. We tried chemotherapy with nivolmab and imatinib for this patient, whereas they showed the partial effect. The genetic analysis revealed somatic TP53 c.569C>T, (p.P190L) mutation in chordoma specimen. In the past literature, we found only one study of the adult chordoma cases, in which majority of the patients had somatic TP53 mutation (p.P72R). Further investigation with large number of the cases is essential to clarify the molecular biology of pediatric chordomas.

scholarly journals Image-Guided Multisession Radiosurgery of Skull Base Meningiomas

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3569
Author(s):  
Alfredo Conti ◽  
Antonio Pontoriero ◽  
Giuseppe Iatì ◽  
Salvatore M. Cardali ◽  
Anna Brogna ◽  
...  
Keyword(s):  
Skull Base ◽  
Stereotactic Radiosurgery ◽  
Cranial Nerves ◽  
Progression Free Survival ◽  
Motor Deficits ◽  
Intracranial Meningioma ◽  
Treatment Schedule ◽  
Fractionated Radiotherapy ◽  
Patient Reported ◽  
Skull Base Meningiomas

Background: The efficacy of single-session stereotactic radiosurgery (sSRS) for the treatment of intracranial meningioma is widely recognized. However, sSRS is not always feasible in cases of large tumors and those lying close to critically radiation-sensitive structures. When surgery is not recommended, multi-session stereotactic radiosurgery (mSRS) can be applied. Even so, the efficacy and best treatment schedule of mSRS are not yet established. The aim of this study is to validate the role of mSRS in the treatment of skull base meningiomas. Methods: A retrospective analysis of patients with skull base meningiomas treated with mSRS (two to five fractions) at the University of Messina, Italy, from 2008 to 2018, was conducted. Results: 156 patients met the inclusion criteria. The median follow-up period was 36.2 ± 29.3 months. Progression-free survival at 2-, 5-, and 10- years was 95%, 90%, and 80.8%, respectively. There were no new visual or motor deficits, nor cranial nerves impairments, excluding trigeminal neuralgia, which was reported by 5.7% of patients. One patient reported carotid occlusion and one developed brain edema. Conclusion: Multisession radiosurgery is an effective approach for skull base meningiomas. The long-term control is comparable to that obtained with conventionally-fractionated radiotherapy, while the toxicity rate is very limited.

The Extraocular Muscles and Diplopia

2014 ◽  
pp. 124-161
Author(s):  
Shirley H. Wray ◽  
Shirley H. Wray
Keyword(s):  
Eye Movements ◽  
Nerve Palsy ◽  
Neuromuscular Junctions ◽  
Cranial Nerves ◽  
Abducens Nerve ◽  
Extraocular Muscles ◽  
Oblique Muscle ◽  
Oculomotor Nerve Palsy ◽  
Subjective Complaint ◽  
Oculomotor Nuclei

deals with action and innervation of the extraocular muscles. In their intact state, the extraocular muscles and the cranial nerves that innervate them are responsible for every movement of the eyes signaled by the cortex. Diplopia, or double vision, is the commonest subjective complaint associated with a lesion affecting the extraocular muscles, their neuromuscular junctions, the oculomotor nuclei or nerve, or pathways in the brainstem that maintain alignment of the eyes. The diplopia history focuses on distinguishing monocular from binocular diplopia and the diplopia examination pays attention to head position, ocular alignment, and the range of eye movements during monocular and binocular viewing as keys to diagnosis. Diplopia with full eye movements is fully discussed. Four illustrative cases are presented: episodic diplopia due to ocular myasthenia gravis; a case of esotropia (paresis of the lateral rectus with inward deviation of the eye) due to an abducens nerve palsy; a case of exotropia (paresis of the medial rectus with outward deviation of the eye) due to a fascicular oculomotor nerve palsy; and a case of hypertropia (vertical misalignment of the eyes due to paresis of the superior oblique muscle vs. skew deviation) caused by a post-traumatic trochlear nerve palsy.

A Side Door to Meckel's Cave: Anatomic Feasibility Study for the Lateral Transorbital Approach

2017 ◽  
Vol 13 (5) ◽  
pp. 614-621 ◽  
Author(s):  
Blake Harrison Priddy ◽  
Cristian Ferrareze Nunes ◽  
Andre Beer-Furlan ◽  
Ricardo Carrau ◽  
Iacopo Dallan ◽  
...  
Keyword(s):  
Skull Base ◽  
Surgical Navigation ◽  
Cranial Nerves ◽  
Anatomical Study ◽  
Middle Cranial Fossa ◽  
Middle Fossa ◽  
Meckel’S Cave ◽  
Side Door ◽  
Meckel's Cave ◽  
Brain Retraction

Abstract BACKGROUND: In the last decade, endoscopic skull base surgery has significantly developed and generated a plethora of techniques and approaches for access to the cranial ventral floor. However, the exploration for the least-aggressive, maximally efficient approach continues. OBJECTIVE: To describe in detail an anatomical study, along with the technical nuances of a novel endoscopic approach to Meckel's Cave (MC) using a lateral transorbital (LTO) route. METHODS: Eighteen orbits of injected cadaveric specimens were operated on, using an endoscopic LTO approach to MC, middle cranial fossa, and paramedian skull base preserving the orbital rim. Surgical navigation and an after-the-fact infratemporal craniectomy were utilized to identify the limits of the approach. RESULTS: Following a transorbital approach opening a trapezoid window at the superolateral aspect (average 166.7 mm2), a middle fossa “peeling” and full visualization of MC was accomplished with no difficulties in all specimens. The entire approach was performed extradurally without the need to expose the temporal lobe. CONCLUSION: In a cadaveric model, the endoscopic LTO approach affords a direct route to access MC. Its main advantage is that it is minimally disruptive in nature, less brain retraction is required, and it reaches the middle fossa in an anterolateral perspective. It also requires no manipulation of the temporalis muscle, limited cosmetic incision, and rapid recovery. It seems a viable alternative to traditional approaches for lesions lateral to the cranial nerves at the cavernous sinus and MC, that is, schwannomas. Clinical utilization of this approach will challenge its efficacy and identify limitations.

Transtemporal Approach to the Skull Base: An Anatomical Study

Neurosurgery ◽  
1986 ◽  
Vol 19 (5) ◽  
pp. 799-808 ◽  
Author(s):  
N. Sekhar Laligam ◽  
Estonillo Rodrigo
Keyword(s):  
Facial Nerve ◽  
Vertebral Artery ◽  
Skull Base ◽  
Medial Temporal Lobe ◽  
Case Reports ◽  
Cranial Nerves ◽  
Sigmoid Sinus ◽  
Anterior Surface ◽  
Advantages And Disadvantages ◽  
Dural Opening

Abstract The surgical anatomy of a transtemporal approach to the structures of the clivus was defined with the aid of dissections in 10 cadaver heads. The steps in the dissection consisted of first exposing the cervical internal carotid artery (ICA), the internal jugular vein, and the caudal cranial nerves, each at the skull base; then performing small retromastoid and temporal craniotomies; and, finally, drilling away the petrous and tympanic bone to expose the intratemporal parts of the facial nerve, the petrous ICA, the sigmoid sinus, and the jugular bulb. To expose the structures of the lower clivus, the sigmoid sinus was ligated and divided, the facial nerve was displaced anterosuperiorly, and the inner ear structures were preserved. Dural opening exposed the anterolateral and anterior surfaces of the medulla, the pontomedullary junction, and the spinomedullary junction. The ipsilateral vertebral artery and often the contralateral vertebral artery and the vertebrobasilar junction, the caudal cranial nerves, and the origin of the 6th, 7th, and 8th cranial nerves were well exposed. To expose the structures of the middle clivus, we drilled away the labyrinth, the cochlea, and a portion of the clival bone. The facial nerve was displaced posteroinferiorly. Dural opening exposed the ipsilateral anterior surface of the pons, the midbasilar artery, and the ipsilateral 5th, 6th, 7th, and 8th cranial nerves. A portion of the contralateral anterior surface of the pons was also exposed at times. The superior limit of this exposure was just above the origin of the trigeminal nerve. The exposure of the upper clival structures was limited with this approach, and required medial temporal lobe retraction. Two case reports are included to illustrate the application of the transtemporal approach to the exposure and clipping of aneurysms of the vertebrobasilar system. The advantages and disadvantages of this approach are discussed.

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