scholarly journals Microsurgical anatomy and approaches around the lateral recess with special reference to entry into the pons

2018 ◽  
Vol 129 (3) ◽  
pp. 740-751 ◽  
Author(s):  
Osamu Akiyama ◽  
Ken Matsushima ◽  
Maximiliano Nunez ◽  
Satoshi Matsuo ◽  
Akihide Kondo ◽  
...  
Keyword(s):  
Surgical Approaches ◽  
Morphometric Study ◽  
Microsurgical Anatomy ◽  
Entry Zone ◽  
Lateral Recess ◽  
Fiber Tracts ◽  
Adjacent Structures ◽  
Microsurgical Techniques ◽  
Safe Entry Zone ◽  
Wide Exposure

OBJECTIVEThe lateral recess is a unique structure communicating between the ventricle and cistern, which is exposed when treating lesions involving the fourth ventricle and the brainstem with surgical approaches such as the transcerebellomedullary fissure approach. In this study, the authors examined the microsurgical anatomy around the lateral recess, including the fiber tracts, and analyzed their findings with respect to surgical exposure of the lateral recess and entry into the lower pons.METHODSTen cadaveric heads were examined with microsurgical techniques, and 2 heads were examined with fiber dissection to clarify the anatomy between the lateral recess and adjacent structures. The lateral and medial routes directed to the lateral recess in the transcerebellomedullary fissure approach were demonstrated. A morphometric study was conducted in the 10 cadaveric heads (20 sides).RESULTSThe lateral recess was classified into medullary and cisternal segments. The medial and lateral routes in the transcerebellomedullary fissure approach provided access to approximately 140º–150º of the posteroinferior circumference of the lateral recess. The floccular peduncle ran rostral to the lateral recess, and this region was considered to be a potential safe entry zone to the lower pons. By appropriately selecting either route, medial-to-lateral or lateral-to-medial entry axis is possible, and combining both routes provided wide exposure of the lower pons around the lateral recess.CONCLUSIONSThe medial and lateral routes of the transcerebellomedullary fissure approach provided wide exposure of the lateral recess, and incision around the floccular peduncle is a potential new safe entry zone to the lower pons.

scholarly journals Microsurgical Anatomy and Approaches around the Lateral Recess with Novel Safe Entry Zone into the Pons

2018 ◽  
Vol 79 (S 01) ◽  
pp. S1-S188
Author(s):  
Osamu Akiyama ◽  
Ken Matsushima ◽  
Nunez Maximiliano ◽  
Satoshi Matsuo ◽  
Akihide Kondo ◽  
...  
Keyword(s):  
Microsurgical Anatomy ◽  
Entry Zone ◽  
Lateral Recess ◽  
Safe Entry Zone

scholarly journals Pterygopalatine Fossa: Microsurgical Anatomy and its Relevance for Skull Base Surgery

2020 ◽  
Author(s):  
Gustavo Rassier Isolan ◽  
Julio Mocellin Bernardi ◽  
João Paulo Mota Telles ◽  
Nícollas Nunes Rabelo ◽  
Eberval Gadelha Figueiredo
Keyword(s):  
Skull Base ◽  
The Body ◽  
Pterygopalatine Fossa ◽  
Surgical Approaches ◽  
Maxillary Artery ◽  
Microsurgical Anatomy ◽  
Extensive Resection ◽  
Maxillary Nerve ◽  
Adjacent Structures ◽  
Surgical Field

Abstract Introduction The purpose of this study was to define the anatomical relationships of the pterygopalatine fossa (PPF) and its operative implications in skull base surgical approaches. Methods Ten cadaveric heads were dissected at the Dianne and M Gazi Yasargil Educational Center MicrosurgicaLaboratory, in Little Rock, AK, USA. The PPF was exposed through an extended dissection with mandible and pterygoid plate removal. Results The PPF has the shape of an inverted cone. Its boundaries are the pterygomaxillary fissure; the maxilla, anteriorly; the medial plate of the pterygoid process, and greater wing of the sphenoid process, posteriorly; the palatine bone, medially; and the body of the sphenoid process, superiorly. Its contents are the maxillary division of the trigeminal nerve and its branches; the pterygopalatine ganglion; the pterygopalatine portion of the maxillary artery (MA) and its branches; and the venous network. Differential diagnosis of PPF masses includes perineural tumoral extension along the maxillary nerve, schwannomas, neurofibromas, angiofibromas, hemangiomas, and ectopic salivary gland tissue. Transmaxillary and transpalatal approaches require extensive resection of bony structures and are narrow in the deeper part of the approach, impairing the surgical vision and maneuverability. Endoscopic surgery solves this problem, bringing the light source to the center of the surgical field, allowing proper visualization of the surgical field, extreme close-ups, and different view angles. Conclusion We provide detailed information on the fossa's boundaries, intercommunications with adjacent structures, anatomy of the maxillary artery, and its variations. It is discussed in the context of clinical affections and surgical approaches of this specific region, including pterygomaxillary disjunction and skull base tumors.

Comprehensive anatomy of the foramen ovale critical to percutaneous stereotactic radiofrequency rhizotomy: cadaveric study of dry skulls

2020 ◽  
Vol 132 (5) ◽  
pp. 1414-1422
Author(s):  
Adel Elnashar ◽  
Smruti K. Patel ◽  
Almaz Kurbanov ◽  
Kseniya Zvereva ◽  
Jeffrey T. Keller ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Facial Pain ◽  
Preoperative Imaging ◽  
Morphometric Study ◽  
Microsurgical Anatomy ◽  
Foramen Ovale ◽  
Percutaneous Approach ◽  
Head Ct ◽  
Adjacent Structures ◽  
Shape And Size

OBJECTIVEPercutaneous stereotactic radiofrequency rhizotomy (PSR) is often used to treat trigeminal neuralgia, a serious condition that results in lancinating, episodic facial pain. Thorough understanding of the microsurgical anatomy of the foramen ovale (FO) and its surrounding structures is required for efficient, effective, and safe use of this technique. This morphometric study compares anatomical and surgical orientations to identify the variations of the FO and assess cannulation difficulty.METHODSBilateral foramina from 174 adult human dry skulls (348 foramina) were analyzed using anatomical and surgical orientations in photographs from standardized projections. Measurements were obtained for shape, size, adjacent structures, and morphometric variability effect on cannulation. The risk of potential injury to surrounding structures was also assessed.RESULTSThe authors identified 6 distinctive shapes of the FO and 5 anomalous variants from the anatomical view, and 6 shapes from the surgical view. In measurements of surface area of this foramen obtained using the surgical view, loss (average 18.5% ± 5.7%) was significant compared with the anatomical view. Morphometrically, foramen size varied significantly and obstruction from a calcified pterygoalar ligament occurred in 7.8% of specimens. Importantly, 8% of foramina were difficult to cannulate, thus posing a 12% risk of inadvertent cannulation of the foramen lacerum.CONCLUSIONSSignificant variability in the FO’s shape and size probably affected its safe and effective cannulation. Preoperative imaging by 3D head CT may be helpful in predicting ease of cannulation and in guiding treatment decisions, such as a percutaneous approach over microvascular decompression or radiosurgery.

The Dentate Nucleus and Its Projection System in the Human Cerebellum

Neurosurgery ◽  
2014 ◽  
Vol 74 (4) ◽  
pp. 401-425 ◽  
Author(s):  
Akin Akakin ◽  
Maria Peris-Celda ◽  
Turker Kilic ◽  
Askin Seker ◽  
Antonio Gutierrez-Martin ◽  
...  
Keyword(s):  
Fourth Ventricle ◽  
Dentate Nucleus ◽  
Diffusion Tensor ◽  
The Elderly ◽  
Surgical Approaches ◽  
Microsurgical Anatomy ◽  
Projection System ◽  
Anatomic Structure ◽  
Surgical Interventions ◽  
Fiber Tracts

ABSTRACT BACKGROUND: Neurosurgical management of cerebellar lesions remains challenging. Thus, it is important to have sound knowledge of the microsurgical anatomy of the cerebellum and dentate nucleus (DN) and to define different types of exposure in a variety of surgical interventions. OBJECTIVE: To examine the anatomy of the DN from a neurosurgical viewpoint using fiber tracking techniques. METHODS: Ten formalin-fixed human hemispheres were dissected with the Ludwig and Klingler fiber dissection technique under × 6 to × 40 magnification. Anatomic images were created with 3-dimensional diffusion tensor imaging. The relationships of the DN to tentorium and suboccipital and lateral surfaces of the cerebellum and its spatial positioning relative to different surgical approaches in the cerebellum and fourth ventricle were examined. The fiber tracts terminating at and surrounding the DN were defined. RESULTS: The DN is at greater risk of being injured in the transvermian and supratonsillar approaches to the cerebellum and fourth ventricle, with lesser risk in the telovelar and subtonsillar approaches. Superior approaches are safer compared with other approaches. CONCLUSION: The DN represents an important anatomic structure in surgical interventions involving the posterior fossa, particularly in the elderly because of the common occurrence of atrophy-related problems in this age group. Functionally and anatomically, the DN is closely related to the superior and middle cerebellar peduncles. The inferior cerebellar peduncle poses positional risks because it follows an anterior and superior course relative to the DN. The telovelar approach is a safer procedure for interventions involving the pathological lesions of the fourth ventricle floor.

Posterior petrosectomy for resection of pontine cavernous malformation

2019 ◽  
Vol 1 (2) ◽  
pp. V18
Author(s):  
Avital Perry ◽  
Thomas J. Sorenson ◽  
Christopher S. Graffeo ◽  
Colin L. Driscoll ◽  
Michael J. Link
Keyword(s):  
Real Time ◽  
Surgical Resection ◽  
Cavernous Malformation ◽  
Low Pressure ◽  
Vascular Lesions ◽  
Cavernous Malformations ◽  
Entry Zone ◽  
Microsurgical Techniques ◽  
Safe Entry Zone ◽  
Ultrasound Probes

Cavernous malformations (CMs) are low-pressure, focal, vascular lesions that may occur within the brainstem and require treatment, which can be a substantial challenge. Herein, we demonstrate the surgical resection of a hemorrhaged brainstem CM through a posterior petrosectomy approach. After dissection of the overlying vascular and meningeal structures, a safe entry zone into the brainstem is identified based on local anatomy and intraoperative neuronavigation. Small ultrasound probes can also be useful for obtaining real-time intraoperative feedback. The CM is internally debulked and resected in a piecemeal fashion through an opening smaller than the CM itself. As brainstem CMs are challenging lesions, knowledge of several surgical nuances and adoption of careful microsurgical techniques are requisite for success.The video can be found here: https://youtu.be/szB6YpzkuCo.

scholarly journals Microsurgical and endoscopic approaches to the pulvinar

2017 ◽  
Vol 127 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Osamu Akiyama ◽  
Ken Matsushima ◽  
Abuzer Gungor ◽  
Satoshi Matsuo ◽  
Dylan J. Goodrich ◽  
...  
Keyword(s):  
Anterior Wall ◽  
Surgical Approaches ◽  
Superior Parietal Lobule ◽  
Surgical Microscope ◽  
Adjacent Structures ◽  
Microsurgical Techniques ◽  
Supracerebellar Infratentorial Approach ◽  
Vascular Structures ◽  
Formalin Fixed ◽  
Different Parts

OBJECTIVEApproaches to the pulvinar remain challenging because of the depth of the target, surrounding critical neural structures, and complicated arterial and venous relationships. The purpose of this study was to compare the surgical approaches to different parts of the pulvinar and to examine the efficacy of the endoscope as an adjunct to the operating microscope in this area.METHODSThe pulvinar was examined in 6 formalin-fixed human cadaveric heads through 5 approaches: 4 above and 1 below the tentorium. Each approach was performed using both the surgical microscope and 0° or 45° rigid endoscopes.RESULTSThe pulvinar has a lateral ventricular and a medial cisternal surface that are separated by the fornix and the choroidal fissure, which wrap around the posterior surface of the pulvinar. The medial cisternal part of the pulvinar can be further divided into upper and lower parts. The superior parietal lobule approach is suitable for lesions in the upper ventricular and cisternal parts. Interhemispheric precuneus and posterior transcallosal approaches are suitable for lesions in the part of the pulvinar forming the anterior wall of the atrium and adjacent cisternal part. The posterior interhemispheric transtentorial approach is suitable for lesions in the lower cisternal part and the supracerebellar infratentorial approach is suitable for lesions in the inferior and medial cisternal parts.The microscope provided satisfactory views of the ventricular and cisternal surfaces of the pulvinar and adjacent neural and vascular structures. The endoscope provided multi-angled and wider views of the pulvinar and adjacent structures.CONCLUSIONSA combination of endoscopic and microsurgical techniques allows optimal exposure of the pulvinar.

Revising the Indications of Transtemporal Surgical Approaches in the Modern Endoscopic Era of Skull Base Surgery: A Dying Art

2020 ◽  
Author(s):  
Ravi Sankar Manogaran ◽  
Raj Kumar ◽  
Arulalan Mathialagan ◽  
Anant Mehrotra ◽  
Amit Keshri ◽  
...  
Keyword(s):  
Skull Base ◽  
Surgical Approach ◽  
Nerve Palsy ◽  
Tertiary Care ◽  
Surgical Approaches ◽  
Microsurgical Anatomy ◽  
Complete Excision ◽  
Lateral Skull Base ◽  
The Individual ◽  
Selection Of

Abstract Objectives The aim of the study is to emphasize and explore the possible transtemporal approaches for spectrum of complicated lateral skull base pathologies. Design Retrospective analysis of complicated lateral skull base pathologies was managed in our institute between January 2017 and December 2019. Setting The study was conducted in a tertiary care referral center. Main Outcome Measures The study focused on the selection of approach based on site and extent of the pathology, the surgical nuances for each approach, and the associated complications. Results A total of 10 different pathologies of the lateral skull base were managed by different transtemporal approaches. The most common complication encountered was facial nerve palsy (43%, n = 6). Other complications included cerebrospinal fluid (CSF) collection (15%, n = 2), cosmetic deformity (24%, n = 4), petrous internal carotid artery injury (7%, n = 1), and hypoglossal nerve palsy (7%, n = 1). The cosmetic deformity included flap necrosis (n = 2) and postoperative bony defects leading to contour defects of the scalp (n = 2). Conclusion Surgical approach should be tailored based on the individual basis, to obtain adequate exposure and complete excision. Selection of appropriate surgical approach should also be based on the training and preference of the operating surgeon. Whenever necessary, combined surgical approaches facilitating full tumor exposure are recommended so that complete tumor excision is feasible. This requires a multidisciplinary team comprising neurosurgeons, neuro-otologist, neuroanesthetist, and plastic surgeons. The surgeon must know precise microsurgical anatomy to preserve the adjacent nerves and vessels, which is necessary for better surgical outcomes.

scholarly journals Primary Malignant Orbital Tumors

2021 ◽  
Vol 82 (01) ◽  
pp. 081-090
Author(s):  
Jacquelyn Laplant ◽  
Kimberly Cockerham
Keyword(s):  
Multimodal Therapy ◽  
Surgical Techniques ◽  
Surgical Approaches ◽  
Imaging Features ◽  
Orbital Surgery ◽  
Diagnosis And Management ◽  
Microsurgical Techniques ◽  
Invasive Techniques ◽  
Traditional Approaches ◽  
Orbital Imaging

Abstract Objective Primary orbital malignancy is rare. Awareness of the characteristic clinical and imaging features is imperative for timely identification and management. Surgery remains an important diagnostic and treatment modality for primary orbital malignancy, but determining the optimal surgical approach can be challenging. The purpose of this article is to explore recent advances in the diagnosis, management, and surgical approaches for primary orbital malignancies. Design In this review, the clinical presentation, imaging features, and medical and surgical management of primary orbital malignancies with representative cases will be discussed. Setting Outpatient and inpatient hospital settings. Participants Patients with diagnosed primary orbital malignancies. Main Outcome Measures Descriptive outcomes. Results Advancements in orbital imaging, microsurgical techniques, and multimodal therapy have improved the diagnosis and management of primary orbital malignancies. Special considerations for biopsy or resection are made based on the tumor's location, characteristics, nearby orbital structures, and goals of surgery. Minimally invasive techniques are supplanting traditional approaches to orbital surgery with less morbidity. Conclusions Advances in imaging technologies and surgical techniques have facilitated the diagnosis and management of primary orbital malignancies. Evolution toward less invasive orbital surgery with focus on preservation and restoration of function is underway.

Surgery of Petroclival Meningiomas: Report of 24 Cases

Neurosurgery ◽  
1989 ◽  
Vol 24 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Madjid Samii ◽  
Mario Ammirati ◽  
Ahmed Mahran ◽  
Walter Bini ◽  
Abholgasse Sepehrnia
Keyword(s):  
Cranial Nerve ◽  
Transverse Sinus ◽  
Surgical Approaches ◽  
Common Symptom ◽  
City Hospital ◽  
Petroclival Meningiomas ◽  
Number Of Patients ◽  
Microsurgical Techniques ◽  
Total Tumor Removal ◽  
The City

Abstract Twenty-four patients with petroclival meningiomas were operated upon at the neurosurgical clinic of the City Hospital of Hannover between 1978 and 1987. Seventeen were women and seven men; the mean age was 45 years. Symptoms were usually present for more than 2 years before the diagnosis was made. The most common symptom was disturbance of gait; the most common preoperative sign was cranial nerve deficit, mainly of the 7th and 8th nerves. Preoperative neuroradiological evaluation included computed tomography and four-vessel cerebral angiography. Fifteen patients (62%) had a tumor larger than 2.5 cm in its major diameter. The surgical approaches used were the retromastoid, pterional, subtemporal, and combined retromastoid-subtemporal. We developed a modification of the retromastoid-subtemporal approach with preservation of the transverse sinus and used this in the last 2 patients. There was no postoperative death; 11 patients (46%) suffered postoperative complications, mainly in the form of cranial nerve deficits, often reversible. “Total” tumor removal was achieved in 17 patients (71%). Twenty patients (83%) were independent at the time of discharge from the hospital. With accurate neuroradiological evaluation, careful choice of the surgical approach, and sound application of microsurgical techniques, petroclival meningiomas may be “totally” and safely resected in a significant number of patients.

The Medial Wall of the Cavernous Sinus: Microsurgical Anatomy

Neurosurgery ◽  
2004 ◽  
Vol 55 (1) ◽  
pp. 179-190 ◽  
Author(s):  
Alexandre Yasuda ◽  
Alvaro Campero ◽  
Carolina Martins ◽  
Albert L. Rhoton ◽  
Guilherme C. Ribas
Keyword(s):  
Pituitary Gland ◽  
Cavernous Sinus ◽  
Thin Sheet ◽  
Single Layer ◽  
Lateral Wall ◽  
The Body ◽  
Medial Wall ◽  
Microsurgical Anatomy ◽  
Pituitary Fossa ◽  
Adjacent Structures

Abstract OBJECTIVE: This study was conducted to clarify the boundaries, relationships, and components of the medial wall of the cavernous sinus (CS). METHODS: Forty CSs, examined under ×3 to ×40 magnification, were dissected from lateral to medial in a stepwise fashion to expose the medial wall. Four CSs were dissected starting from the midline to lateral. RESULTS: The medial wall of the CS has two parts: sellar and sphenoidal. The sellar part is a thin sheet that separates the pituitary fossa from the venous spaces in the CS. This part, although thin, provided a barrier without perforations or defects in all cadaveric specimens studied. The sphenoidal part is formed by the dura lining the carotid sulcus on the body of the sphenoid bone. In all of the cadaveric specimens, the medial wall seemed to be formed by a single layer of dura that could not be separated easily into two layers as could the lateral wall. The intracavernous carotid was determined to be in direct contact with the pituitary gland, being separated from it by only the thin sellar part of the medial wall in 52.5% of cases. In 39 of 40 CSs, the venous plexus and spaces in the CS extended into the narrow space between the intracavernous carotid and the dura lining the carotid sulcus, which forms the sphenoidal part of the medial wall. The lateral surface of the pituitary gland was divided axially into superior, middle and inferior thirds. The intracavernous carotid coursed lateral to some part of all the superior, middle, and inferior thirds in 27.5% of the CSs, along the inferior and middle thirds in 32.5%, along only the inferior third in 35%, and below the level of the gland and sellar floor in 5%. In 18 of the 40 CSs, the pituitary gland displaced the sellar part of the medial wall laterally and rested against the intracavernous carotid, and in 6 there was a tongue-like lateral protrusion of the gland that extended around a portion of the wall of the intracavernous carotid. No defects were observed in the sellar part of the medial wall, even in the presence of these protrusions. CONCLUSION: The CS has an identifiable medial wall that separates the CS from the sella and capsule of the pituitary gland. The medial wall has two segments, sellar and sphenoidal, and is formed by just one layer of dura that cannot be separated into two layers as can the lateral wall of the CS. In this study, the relationships between the medial wall and adjacent structures demonstrated a marked variability.

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