The foramen lacerum: surgical anatomy and relevance for endoscopic endonasal approaches

OBJECTIVEThe foramen lacerum is a relevant skull base structure that has been neglected for many years. From the endoscopic endonasal perspective, the foramen lacerum is a key structure due to its location at the crossroad between the sagittal and coronal planes. The objective of this study was to provide a detailed investigation of the surgical anatomy of the foramen lacerum and its adjacent structures based on anatomical dissections and imaging studies, propose several relevant key surgical landmarks, and demonstrate the surgical technique for its full exposure with several illustrative cases.METHODSTen colored silicone-injected anatomical specimens were dissected using a transpterygoid approach to the foramen lacerum region in a stepwise manner. Five similar specimens were used for a comparative transcranial approach. The osseous anatomy was examined in 32 high-resolution multislice CT studies and 1 disarticulated skull. Representative cases were selected to illustrate the application of the findings.RESULTSThe pterygosphenoidal fissure is the synchondrosis between the lacerum process of the pterygoid bone and the floor of the sphenoid bone. It constantly converges with the posterior end of the vidian canal at a 45° angle, and its posterolateral end points directly to the lacerum foramen. The pterygoid tubercle separates the vidian canal from the pterygosphenoidal fissure, and forms the anterior wall of the lower part of the foramen lacerum. The lingual process, which forms the lateral wall of the foramen lacerum, was identified in 53 of 64 sides and featured an average height of 5 mm. The mandibular strut separates the foramen lacerum from the foramen ovale and had an average width of 5 mm.CONCLUSIONSThis study provides relevant surgical landmarks and a systematic approach to the foramen lacerum by defining anterior, medial, lateral, and inferior walls that may facilitate its safe exposure for effective removal of lesions while minimizing the risk of injury to the internal carotid artery.

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The medial wall of the cavernous sinus. Part 1: Surgical anatomy, ligaments, and surgical technique for its mobilization and/or resection

Journal of Neurosurgery ◽

10.3171/2018.3.jns18596 ◽

2019 ◽

Vol 131 (1) ◽

pp. 122-130 ◽

Cited By ~ 6

Author(s):

Huy Q. Truong ◽

Stefan Lieber ◽

Edinson Najera ◽

Joao T. Alves-Belo ◽

Paul A. Gardner ◽

...

Keyword(s):

Cavernous Sinus ◽

Single Layer ◽

Lateral Wall ◽

Anterior Wall ◽

Surgical Anatomy ◽

Medial Wall ◽

Vertical Segment ◽

Anterior Clinoid Process ◽

Endoscopic Endonasal

OBJECTIVEThe medial wall of the cavernous sinus (CS) is often invaded by pituitary adenomas. Surgical mobilization and/or removal of the medial wall remains a challenge.METHODSEndoscopic endonasal dissection was performed in 20 human cadaver heads. The configuration of the medial wall, its relationship to the internal carotid artery (ICA), and the ligamentous connections in between them were investigated in 40 CSs.RESULTSThe medial wall of the CS was confirmed to be an intact single layer of dura that is distinct from the capsule of the pituitary gland and the periosteal layer that forms the anterior wall of the CS. In 32.5% of hemispheres, the medial wall was indented by and/or well adhered to the cavernous ICA. The authors identified multiple ligamentous fibers that anchored the medial wall to other walls of the CS and/or to specific ICA segments. These parasellar ligaments were classified into 4 groups: 1) caroticoclinoid ligament, spanning from the medial wall and the middle clinoid toward the clinoid ICA segment and anterior clinoid process; 2) superior parasellar ligament, connecting the medial wall to the horizontal cavernous ICA and/or lateral wall of the CS; 3) inferior parasellar ligament, bridging the medial wall to the anterior wall of the CS or anterior surface of the short vertical segment of the cavernous ICA; and 4) posterior parasellar ligament, which anchors the medial wall to the short vertical segment of the cavernous ICA and/or the posterior carotid sulcus. The caroticoclinoid ligament and inferior parasellar ligament were present in most CSs (97.7% and 95%, respectively), while the superior and posterior parasellar ligaments were identified in approximately half of the CSs (57.5% and 45%, respectively). The caroticoclinoid ligament was the strongest and largest ligament, and it was typically assembled as a group of ligaments with a fan-like arrangement. The inferior parasellar ligament was the first to be encountered after opening the anterior wall of the CS during an interdural transcavernous approach.CONCLUSIONSThe authors introduce a classification of the parasellar ligaments and their role in anchoring the medial wall of the CS. These ligaments should be identified and transected to safely mobilize the medial wall away from the cavernous ICA during a transcavernous approach and for safe and complete resection of adenomas that selectively invade the medial wall.

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Utility of 3D CT Rib Study in Presurgical Planning of Autologous Ear Graft for Pinna Reconstruction in Microtia

Indian Journal of Radiology and Imaging ◽

10.1055/s-0041-1735866 ◽

2021 ◽

Author(s):

Sneha S. Zanje ◽

Nikhil V. Kamat ◽

Kunal K. Taware ◽

M L. Rokade ◽

Ashesh C. Bhumkar

Keyword(s):

Computed Tomography ◽

Average Length ◽

Costal Cartilage ◽

Multislice Ct ◽

Average Height ◽

3D Ct ◽

High Resolution Computed Tomography ◽

Average Width ◽

Presurgical Planning ◽

The Right

Abstract Purpose The aim of this study was to demonstrate the utility of three-dimensional computed tomography (3D) CT rib study in presurgical planning to select the autologous rib cartilage graft for pinna reconstruction. Materials and Methods Total of 35 patients of microtia for autologous rib graft from April 2017 to February 2020 were evaluated in this study. All patients had a plain low-dose multislice CT chest. The length of costal cartilages of sixth to ninth ribs bilaterally and width and height of sixth and seventh rib costal cartilage synchondrosis were measured in 3D reconstructed true size coronal images with best possible length displayed. All patients had high-resolution computed tomography (HRCT) temporal studies done to evaluate for associated anomalies in external canal, middle ear cavities, and inner ear structures. Eleven patients had simultaneous HRCT temporal bone done after plain CT chest and rest who had done recent prior study were reviewed without repetition of study. Results There were 19 males and 16 females for 3D CT rib study. Average age of the participants was 16.5 years. The average width of synchondrosis of sixth and seventh rib was 15.4 mm on right side and 14.7 mm on left side, average height of synchondrosis was 28.5 mm on right side and 30.7 mm on left side. Average length of the eighth rib costal cartilage was 88.6 mm on the right side and 90.5 mm on the left side. Average length of the ninth rib was 63.2 mm on the right side and 58.2 mm on the left side. Costal cartilage calcifications were present in 9 patients. Conclusion Preoperative 3D CT rib study provides accurate measurements of rib stock for sculpting autologous ear graft.

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Anatomic Study of Endoscopic Transnasal Approach to Petrous Apex

E3S Web of Conferences ◽

10.1051/e3sconf/202021803016 ◽

2020 ◽

Vol 218 ◽

pp. 03016

Author(s):

Wenyuan He ◽

Qingying Qin ◽

Guxian Wang

Keyword(s):

Skull Base ◽

Sphenoid Sinus ◽

Lateral Wall ◽

Anterior Wall ◽

Surgical Anatomy ◽

Petrous Apex ◽

Transnasal Approach ◽

Long Time ◽

Endoscopic Transnasal Approach ◽

Micro Drill

With the development of Neurosurgery technology, there has been a qualitative leap forward with the appearance of microanatomy, which makes the deep brain tumors which were hard to be achieved in the past, and effectively reduces the mortality of patients. Petrous apex is a cone-shaped part of the anteromedial part of the temporal bone, which is deep. It has been a challenging area for surgical anatomy for a long time. In this paper, fresh adult perfused cadaveric head specimens and dry adult cadaveric head specimens were taken as the experimental objects. The anterior wall of sphenoid sinus and the internal septum of sphenoid sinus were excised under neuroendoscope. The structures of the lateral wall of sphenoid sinus were identified and dissected. The lateral wall of sphenoid sinus and the bone of skull base were opened with micro drill, The meninges were exposed and cut open, and the related structures were dissected, observed and photographed. The experimental results show that it is relatively safe to operate in the range of less than 8mm, and the rock tip can be found accurately. The measurement of the bony structure of the skull base is helpful for the surgeon to judge the course of the internal carotid artery and its adjacent structure.

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The Medial Wall of the Cavernous Sinus: Microsurgical Anatomy

Neurosurgery ◽

10.1227/01.neu.0000126953.59406.77 ◽

2004 ◽

Vol 55 (1) ◽

pp. 179-190 ◽

Cited By ~ 75

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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Abstract 15632: Phenotypic Overlap Between Left Ventricular Noncompaction and Hypertrophic Cardiomyopathy: A Case Report

Circulation ◽

10.1161/circ.142.suppl_3.15632 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Ethan Senser ◽

Madison Hawkins ◽

Eric M Williams ◽

Lauren Gilstrap

Keyword(s):

Hypertrophic Cardiomyopathy ◽

Cardiac Mri ◽

Genetic Diagnosis ◽

Lateral Wall ◽

Anterior Wall ◽

Left Ventricular ◽

Ventricular Noncompaction ◽

History Of ◽

Clinically Significant

Introduction: Left ventricular non-compaction (LVNC) is characterized by extensively trabeculaed myocardium adjacent to normal compacted myocardium of the left ventricle (LV). Hypertrophic cardiomyopathy (HCM) typically appears as diffuse or segmental LV hypertrophy, with or without outflow tract obstruction. Cardiac sarcomere mutations are present in most HCM cases and have also been identified in LVNC. Whether or not there is clinically significant phenotypic overlap between the two diseases is less well understood. We present a case of known HCM that met criteria for both LVNC and HCM by cardiac MRI. Case: A 49-year old man with HCM due to a c.3742_3759dup variant in MYBPC3 presented to clinic after an episode of syncope and ICD firing. In clinic, the device was interrogated and he was found to have had ventricular flutter which was successfully treated with one shock and a new, high (>20%) burden of premature ventricular beats. An echocardiogram showed a stable ejection fraction at 42%, mild concentric LV hypertrophy without obstruction and a newly dilated LV with an end diastolic diameter of 7.1cm (previously 6.2cm). A cardiac MRI was performed ( Figure ) and showed LV noncompaction and diffuse transmural and mid myocardial hyperenhancement/fibrosis of the septum, basilar lateral wall, anterior wall, and distal right ventricle consistent with patient's long-standing history of hypertrophic cardiomyopathy. Discussion: This case highlights the phenotypic overlap between HCM and LVNC by cardiac MRI. Had this patient not already carried a genetic diagnosis of HCM, he would likely have been diagnosed with LVNC based on this cardiac MRI. The phenotypic overlap in these diseases raises questions about ICD guidelines, the role of anticoagulation and prognosis.

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Age Related Histomorphometrical Studies on the Major Lymphoid Organs of Chicken

Indian Journal of Animal Research ◽

10.18805/ijar.b-4318 ◽

2021 ◽

Author(s):

N. Dahariya ◽

S. Sathapathy ◽

U.K. Mishra ◽

R. Patra ◽

S. Dehury ◽

...

Keyword(s):

Average Length ◽

Bursa Of Fabricius ◽

Maximum Diameter ◽

White Pulp ◽

Average Height ◽

Average Thickness ◽

Average Width ◽

Age Related ◽

Group I ◽

Average Maximum

Background: Hansli chicken is reared in Mayurbhanj and Keonjhar districts of Odisha. They play a vital role in the economic upliftment of poor, landless and marginalised people in the rural areas besides providing them with nutritious egg and meat for consumption.Methods: Hansli chicks and Vencobb broiler chicks were divided into three age groups viz. group I (up to 1 month), group II (1-3 months) and group III (3-6 months) with six birds in each age group. On 4th week, 12th week and 24th week, six birds from each breed were used for the study of histomorphometrical features of the thymus, spleen and bursa of Fabricius. Result: The average thickness of the capsule, cortex and medulla of thymus, average width of thymic lobule and average maximum diameter of Hassall’s corpuscles differed significantly (p≤0.05) between the birds at specific ages. Similarly, the average thickness of the splenic capsule, average width of white pulp, average external transverse and internal longitudinal diameters of trabecular artery, average external longitudinal, internal longitudinal, external transverse and internal transverse diameters of central artery, average longitudinal diameter of capillary, average longitudinal and transverse diameters of splenic nodule, average thickness of PALS and PELS differed significantly (p≤0.05) between the birds at specific ages. The average number of bursal follicles in larger and smaller plicae, average height and width of larger and smaller plicae, average length and width of bursal follicle, average height of columnar cell of pseudostratified FAE and IFE, average nuclear height of FAE and IFE columnar cells differed significantly (p≤0.05) between the birds at specific ages.

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Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Approach to the Orbit

10.1055/s-0041-1725555 ◽

2021 ◽

Author(s):

Laura Salgado-Lopez ◽

Luciano C. Leonel ◽

Michael Obrien ◽

Adedamola Adepoju ◽

Michael J. Link ◽

...

Keyword(s):

Skull Base ◽

Surgical Anatomy ◽

Endoscopic Endonasal Approach ◽

Endonasal Approach ◽

Endoscopic Endonasal

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Surgical nuances for the endoscopic endonasal transpterygoid approach to lateral sphenoid sinus encephaloceles

Neurosurgical FOCUS ◽

10.3171/2012.3.focus1267 ◽

2012 ◽

Vol 32 (6) ◽

pp. E5 ◽

Cited By ~ 30

Author(s):

Richard F. Schmidt ◽

Osamah J. Choudhry ◽

Joseph Raviv ◽

Soly Baredes ◽

Roy R. Casiano ◽

...

Keyword(s):

Skull Base ◽

Sphenoid Sinus ◽

Skull Base Surgery ◽

Surgical Anatomy ◽

Endoscopic Endonasal ◽

Csf Rhinorrhea ◽

Lateral Recess ◽

Sternberg Canal ◽

Deep Location ◽

Repair Techniques

Lateral sphenoid encephaloceles of the Sternberg canal are rare entities and usually present with spontaneous CSF rhinorrhea. Traditionally, these were treated via transcranial approaches, which can be challenging given the deep location of these lesions. However, with advancements in endoscopic skull base surgery, including improved surgical exposures, angled endoscopes and instruments, and novel repair techniques, these encephaloceles can be resected and successfully repaired with purely endoscopic endonasal approaches. In this report, the authors review the endoscopic endonasal transpterygoid approach to the lateral recess of the sphenoid sinus for repair of temporal lobe encephaloceles, including an overview of the surgical anatomy from an endoscopic perspective, and describe the technical operative nuances and surgical pearls for these cases. The authors also present 4 new cases of lateral sphenoid recess encephaloceles that were successfully treated using this approach.

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Endoscopic Endonasal Approaches to the Cavernous Sinus: Surgical Approaches

Neurosurgery ◽

10.1097/00006123-200108000-00017 ◽

2001 ◽

Vol 49 (2) ◽

pp. 354-362 ◽

Cited By ~ 11

Author(s):

Alessandra Alfieri ◽

Hae-Dong Jho

Keyword(s):

Cavernous Sinus ◽

Middle Turbinate ◽

Lateral Wall ◽

Surgical Instruments ◽

Surgical Approaches ◽

Lateral Nasal Wall ◽

Orbital Apex ◽

Superior Orbital Fissure ◽

Endoscopic Endonasal ◽

Surgical Access

Abstract OBJECTIVE After completion of an earlier endoscopic transsphenoidal anatomic study, we studied various endoscopic transsphenoidal approaches using cadaveric specimens to develop endoscopic endonasal surgical approaches to the cavernous sinus. METHODS Ten cavernous sinuses in five artery-injected adult cadaveric heads were studied with 0-, 30-, and 70-degree angled 4-mm rod-lens endoscopes. The extent of the surgical exposure, the skewed endoscopic anatomic view, and the maneuverability of surgical instruments through their relative operating spaces were studied after various endoscopic endonasal approaches via one nostril. RESULTS The paraseptal approach was used between the nasal septum and the middle turbinate and provided exposure at the anteromedial portion of the cavernous sinus. The contralateral paraseptal approach rendered a slightly more medial view at the cavernous sinus than did the ipsilateral approach. This approach offered limited surgical access to the lateral vertical compartment. The middle turbinectomy approach allowed surgical access to the lateral wall of the cavernous sinus, except for the superior orbital fissure and the orbital apex. The middle meatal approach, which was made between the middle turbinate and the lateral nasal wall, revealed the entire lateral vertical compartment of the cavernous sinus, including the orbital apex and the superior orbital fissure. However, its lateral tangential surgical trajectory and the absence of dedicated surgical tools limited the surgeon's surgical maneuverability. A combination of the middle turbinectomy and middle meatal approaches increased the operating space. CONCLUSION Various endoscopic endonasal surgical approaches to the cavernous sinus were studied using adult cadaveric head specimens.

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Endoscopic endonasal transoculomotor triangle approach for adenomas invading the parapeduncular space: surgical anatomy, technical nuances, and case series

Journal of Neurosurgery ◽

10.3171/2017.10.jns17779 ◽

2019 ◽

Vol 130 (4) ◽

pp. 1304-1314 ◽

Cited By ~ 7

Author(s):

Cristian Ferrareze Nunes ◽

Stefan Lieber ◽

Huy Q. Truong ◽

Georgios Zenonos ◽

Eric W. Wang ◽

...

Keyword(s):

Cavernous Sinus ◽

Case Series ◽

Surgical Anatomy ◽

Oculomotor Nerve ◽

Oculomotor Nerve Palsy ◽

Tumor Extension ◽

Endoscopic Endonasal ◽

Transcranial Approach ◽

Surgical Corridor ◽

Dural Opening

OBJECTIVEPituitary adenomas may extend into the parapeduncular space by invading through the roof of the cavernous sinus. Currently, a transcranial approach is the preferred choice, with or without the combination of an endonasal approach. In this paper the authors present a novel surgical approach that takes advantage of the natural corridor provided by the tumor to further open the oculomotor triangle and resect tumor extension into the parapeduncular space.METHODSSix injected specimens were used to demonstrate in detail the surgical anatomy related to the approach. Four cases in which the proposed approach was used were retrospectively reviewed.RESULTSFrom a technical perspective, the first step involves accessing the superior compartment of the cavernous sinus. The interclinoid ligament should be identified and the dura forming the oculomotor triangle exposed. The oculomotor dural opening may be then extended posteriorly toward the posterior petroclinoidal ligament and inferolaterally toward the anterior petroclinoidal ligament. The oculomotor nerve should then be identified; in this series it was displaced superomedially in all 4 cases. The posterior communicating artery should also be identified to avoid its injury. In all 4 cases, the tumor invading the parapeduncular space was completely removed. There were no vascular injuries and only 1 patient had a partial oculomotor nerve palsy that completely resolved in 2 weeks.CONCLUSIONSThe endoscopic endonasal transoculomotor approach is an original alternative for removal of tumor extension into the parapeduncular space in a single procedure. The surgical corridor is increased by opening the dura of the oculomotor triangle and by working below and lateral to the cisternal segment of the oculomotor nerve.

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