Anatomical study of the superior orbital fissure as seen during a pterional approach

2007 ◽  
Vol 106 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Mario Ammirati ◽  
Antonio Bernardo
Keyword(s):  
Anatomical Study ◽  
Pterional Approach ◽  
Superior Orbital Fissure ◽  
Specific Sequence ◽  
Anterior Portion ◽  
Important Landmark ◽  
Controlled Exposure ◽  
Surrounding Areas ◽  
Brain Retraction ◽  
Good Exposure

Object The superior orbital fissure (SOF) is an important landmark in the neurosurgical pterional approach, but the anatomical features of the SOF and the procedures necessary to fully expose it and its contents have not been detailed. Although the pterional approach is commonly used during skull base or vascular surgery by neurosurgeons who may already be familiar with its nuances and anatomical relationships to the SOF, this knowledge may also be useful to the wider neurosurgical community. The authors describe the spatial relationships of the contents of the SOF and suggest a specific sequence of steps for exposing the SOF region in a pterional approach. Methods Using standard microsurgical equipment and instruments, the authors performed 20 pterional approaches in 10 embalmed cadaver heads in which the vascular systems had been injected with colored material. Five sequential steps were delineated for approaching and dissecting the SOF and its contents: 1) drilling the sphenoidal ridge, anterior clinoidal process, and part of the greater and lesser wings of the sphenoid; 2) resecting the dural bridge; 3) detaching the hemispheric dura mater, thereby exposing the anterior portion of the cavernous sinus and the neural component entering the SOF; 4) identifying and dissecting the extraanular structures; and 5) opening the anulus of Zinn and identifying its neural constituents. Conclusions Knowing the 3D relationships of the contents of the SOF encountered in the pterional approach enables safe neurosurgical access to the area. The proposed sequence of steps allows a controlled exposure of the SOF and surrounding areas. Untethering the frontotemporal lobe by transecting the dural bridge connecting the dura to the perior-bita allows good exposure of the basal frontotemporal lobes, both intra- and extradurally, and reduces brain retraction.

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.

scholarly journals Morphometric Comparison of the Pterional Trans-sylvian and the Pretemporal Transclinoidal Approaches to Posterior Communicating Artery Aneurysms: Anatomical Study

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Jaafar Basma ◽  
Kenneth Moore ◽  
Tarek Abuelem ◽  
Khaled Krisht ◽  
L Madison Michael ◽  
...  
Keyword(s):  
Clinical Case ◽  
Internal Carotid ◽  
Focal Point ◽  
Anatomical Study ◽  
Pterional Approach ◽  
Case Examples ◽  
Pterional Craniotomy ◽  
Working Space ◽  
Area 5 ◽  
Ischemic Complications

Abstract INTRODUCTION Due to the advent of endovascular techniques, modern series of surgically treated posterior communicating (Pcom) aneurysms have shown a tendency towards higher complexity and more technical difficulties. The pretemporal approach was described as a valuable extension to the pterional approach in treating basilar apex aneurysms. Its use for clipping of ruptured Pcom aneurysms was associated with decreased ischemic complications. However, its anatomical advantages for Pcom aneurysm surgery have not been previously analyzed. METHODS Six cadaveric heads (12 sides) underwent a sequential dissection, starting with a pterional craniotomy, and then extended to a pretemporal transclinoidal approach. In each step, the following variables were measured, taking the origin of Pcom as a focal point: (1) exposed length of the internal carotid artery (ICA) proximal to the Pcom artery, (2) exposed angular circumference of ICA at the origin of Pcom, (3) deep working area between the optic nerve and tentorium/oculomotor nerve, (4) superficial working area, (5) depth of the exposure and the (6) fronto-temporal (superior posterolateral), and (7) orbito-sphenoidal (inferior anterolateral) angles of exposure. Clinical case examples are used to illustrate the advantages of the pretemporal approach. RESULTS Compared to the pterional craniotomy, the pretemporal transclinoidal approach increased the exposed length of the proximal ICA from 3.3 to 11.7 mm (P = .0001), and its circumference from 5.1 to 7.8 mm (P = .0003), allowing a 210-degree view of the ICA (vs 137.9). The deep and superficial working areas also significantly widened from 53.7 to 92.4 mm2 (P = .0048) and 252.8 to 418.2 mm2 (P = .0001), respectively; while the depth of the exposure was equivalent. The frontotemporal and the sphenosylvian angles increased on average by 17 (P = .0006) and 10 (P = .0037) degrees, respectively. The clinical case examples demonstrate the visual, technical and strategic advantages of the pretemporal approach as a consequence of its anatomical exposure. CONCLUSION The pretemporal approach can be useful for complex Pcom aneurysms by providing easier proximal control, wider working space, aneurysm visualization, and more versatile clipping angles. The enhanced exposure potentially results in a higher rate of complete aneurysm obliteration and complication avoidance.

Microsurgical Approaches to the Medial Temporal Region: An Anatomical Study

2006 ◽  
Vol 59 (suppl_4) ◽  
pp. ONS-279-ONS-308 ◽  
Author(s):  
Alvaro Campero ◽  
Gustavo Tro´ccoli ◽  
Carolina Martins ◽  
Juan C. Fernandez-Miranda ◽  
Alexandre Yasuda ◽  
...  
Keyword(s):  
Anatomical Study ◽  
Middle Part ◽  
Surgical Anatomy ◽  
Surgical Approaches ◽  
Temporal Region ◽  
Anterior Portion ◽  
Posterior Portion ◽  
Medial Surface ◽  
Posterior Group ◽  
Quadrigeminal Plate

Abstract OBJECTIVE: To describe the surgical anatomy of the anterior, middle, and posterior portions of the medial temporal region and to present an anatomic-based classification of the approaches to this area. METHODS: Twenty formalin-fixed, adult cadaveric specimens were studied. Ten brains provided measurements to compare different surgical strategies. Approaches were demonstrated using 10 silicon-injected cadaveric heads. Surgical cases were used to illustrate the results by the different approaches. Transverse lines at the level of the inferior choroidal point and quadrigeminal plate were used to divide the medial temporal region into anterior, middle, and posterior portions. Surgical approaches to the medial temporal region were classified into four groups: superior, lateral, basal, and medial, based on the surface of the lobe through which the approach was directed. The approaches through the medial group were subdivided further into an anterior approach, the transsylvian transcisternal approach, and two posterior approaches, the occipital interhemispheric and supracerebellar transtentorial approaches. @@RESULTS:@@ The anterior portion of the medial temporal region can be reached through the superior, lateral, and basal surfaces of the lobe and the anterior variant of the approach through the medial surface. The posterior group of approaches directed through the medial surface are useful for lesions located in the posterior portion. The middle part of the medial temporal region is the most challenging area to expose, where the approach must be tailored according to the nature of the lesion and its extension to other medial temporal areas. CONCLUSION: Each approach to medial temporal lesions has technical or functional drawbacks that should be considered when selecting a surgical treatment for a given patient. Dividing the medial temporal region into smaller areas allows for a more precise analysis, not only of the expected anatomic relationships, but also of the possible choices for the safe resection of the lesion. The systematization used here also provides the basis for selection of a combination of approaches.

Supraorbital-Pterional Approach to Skull Base Lesions

Neurosurgery ◽  
1987 ◽  
Vol 21 (4) ◽  
pp. 474-477 ◽  
Author(s):  
Ossama Al-Mefty
Keyword(s):  
Skull Base ◽  
Cavernous Sinus ◽  
Surgical Approach ◽  
Cranial Base ◽  
Bone Flap ◽  
Pterional Approach ◽  
Skull Base Lesions ◽  
Single Bone ◽  
Brain Retraction ◽  
Tentorial Notch

Abstract A surgical approach to the skull base is described. It allows excellent exposure of the cranial base with minimal brain retraction. Deep lesions can be handled via subfrontal, transsylvian, or subtemporal routes during the same operation. This approach is most suitable for large lesions in the suprasellar, parasellar, and retrosellar areas and for those that extend into the cavernous sinus, along the tentorial notch, or into the orbit. After the single bone flap is replaced, there is little or no functional, anatomical, or cosmetic deficit. Our experience in 16 cases and suggestion for the use of this approach are presented.

scholarly journals Transtentorial transcollateral sulcus approach to the ventricular atrium: an endoscope-assisted anatomical study

2017 ◽  
Vol 126 (4) ◽  
pp. 1246-1252 ◽  
Author(s):  
Yasser Jeelani ◽  
Abdulkerim Gokoglu ◽  
Tomer Anor ◽  
Ossama Al-Mefty ◽  
Alan R. Cohen
Keyword(s):  
Cortical Thickness ◽  
Lateral Ventricle ◽  
Tracking System ◽  
Anatomical Study ◽  
Parahippocampal Gyrus ◽  
Lingual Gyrus ◽  
Novel Approach ◽  
Collateral Sulcus ◽  
Brain Retraction ◽  
Formalin Fixed

OBJECTIVE Conventional approaches to the atrium of the lateral ventricle may be associated with complications related to direct cortical injury or brain retraction. The authors describe a novel approach to the atrium through a retrosigmoid transtentorial transcollateral sulcus corridor. METHODS Bilateral retrosigmoid craniotomies were performed on 4 formalin-fixed, colored latex–injected human cadaver heads (a total of 8 approaches). Microsurgical dissections were performed under 3× to 24× magnification, and endoscopic visualization was provided by 0° and 30° rigid endoscope lens systems. Image guidance was provided by coupling an electromagnetic tracking system with an open source software platform. Objective measurements on cortical thickness traversed and total depth of exposure were recorded. Additionally, the basal occipitotemporal surfaces of 10 separate cerebral hemisphere specimens were examined to define the surface topography of sulci and gyri, with attention to the appearance and anatomical patterns and variations of the collateral sulcus and the surrounding gyri. RESULTS The retrosigmoid approach allowed for clear visualization of the basal occipitotemporal surface. The collateral sulcus was identified and permitted easy endoscopic access to the ventricular atrium. The conical corridor thus obtained provided an average base working area of 3.9 cm2 at an average depth of 4.5 cm. The mean cortical thickness traversed to enter the ventricle was 1.4 cm. The intraventricular anatomy of the ipsilateral ventricle was defined clearly in all 8 exposures in this manner. The anatomy of the basal occipitotemporal surface, observed in a total of 18 hemispheres, showed a consistent pattern, with the collateral sulcus abutted by the parahippocampal gyrus medially, and the fusiform and lingual gyrus laterally. The collateral sulcus was found to be caudally bifurcated in 14 of the 18 specimens. CONCLUSIONS The retrosigmoid supracerebellar transtentorial transcollateral sulcus approach is technically feasible. This approach has the potential advantage of providing a short and direct path to the atrium, hence avoiding violation of deep neurovascular structures and preserving eloquent areas. Although this approach appears unconventional, it may provide a minimally invasive option for the surgical management of selected lesions within the atrium of the lateral ventricle.

scholarly journals Drilling of the marginal tubercle to enhance exposure via mini pterional approach: An anatomical study and clinical series of 25 sphenoid wing meningiomas

2016 ◽  
Vol 7 (41) ◽  
pp. 989
Author(s):  
KhaledM Aziz ◽  
Nouman Aldahak ◽  
Mohamed El Tantowy ◽  
Derrick Dupre ◽  
Alexander Yu ◽  
...  
Keyword(s):  
Anatomical Study ◽  
Pterional Approach ◽  
Clinical Series

scholarly journals Marginal mandibular branch of the facial nerve: An anatomical study

2010 ◽  
Vol 43 (01) ◽  
pp. 060-064
Author(s):  
Arvinder Pal Singh Batra ◽  
Anupama Mahajan ◽  
Karunesh Gupta
Keyword(s):  
Facial Nerve ◽  
Surgical Procedures ◽  
Anatomical Study ◽  
Facial Artery ◽  
Submandibular Region ◽  
Marginal Mandibular Nerve ◽  
Marginal Mandibular Branch ◽  
Important Landmark ◽  
Mandibular Branch ◽  
Main Factor

ABSTRACTSmile is one of the most natural and important expressions of human emotion. Man uses his lips mainly to register his emotions. Thus, the slightest asymmetry or weakness around the lips and mouth may transform this pleasant expression into embarrassment and distortion. The circumoral musculature, the major part of which is supplied by the marginal mandibular branch of the facial nerve, is the main factor in this expression. Therefore, an injury to this nerve during a surgical procedure can distort the expression of the smile as well as other facial expressions. This nerve often gets injured by surgeons in operative procedures in the submandibular region, like excision of the submandibular gland due to lack of accurate knowledge of variations in the course, branches and relations. In the present study, 50 facial halves were dissected to study the origin, entire course, termination, branches, muscles supplied by it, its anastomoses with other branches of facial nerve on the same as well as on the opposite side and its relations with the surrounding structures. The marginal mandibular branch of the facial nerve was found superficial to the facial artery and (anterior) facial vein in all the cases (100%). Thus the facial artery can be used as an important landmark in locating the marginal mandibular nerve during surgical procedures. Such a study can help in planning precise and accurate incisions and in preventing the unrecognized severance of this nerve during surgical procedures.

The Frontotemporal (Pterional) Approach

Neurosurgery ◽  
2012 ◽  
Vol 71 (2) ◽  
pp. 481-492 ◽  
Author(s):  
Tamer Altay ◽  
William T. Couldwell
Keyword(s):  
Vascular Lesions ◽  
Past Century ◽  
Temporal Region ◽  
Pterional Approach ◽  
Superior Orbital Fissure ◽  
Current Form ◽  
Orbital Roof ◽  
Transcranial Approach ◽  
Related Derivative ◽  
Cranial Fossa

Abstract The frontotemporal, so-called pterional, approach has evolved with the contribution of many neurosurgeons over the past century. It has stood the test of time and has been the most commonly used transcranial approach in neurosurgery. In its current form, drilling the sphenoid wing as far down as the superior orbital fissure with or without the removal of the anterior clinoid, thinning the orbital roof, and opening the Sylvian fissure and basal cisterns are the hallmarks of this approach. Tumoral and vascular lesions involving the sellar/parasellar area, anterior and anterolateral circle of Willis, middle cerebral artery, anterior brainstem, upper basilar artery, insula, basal ganglia, mesial temporal region, anterior cranial fossa, orbit, and optic nerve are within the reach of the frontotemporal approach. In this article, we review the origins, evolution, and modifications of the frontotemporal approach and update the discussion of some of the related derivative procedures.

Anatomical analysis of transoral surgical approaches to the clivus

2006 ◽  
Vol 105 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Vijayabalan Balasingam ◽  
Gregory J. Anderson ◽  
Neil D. Gross ◽  
Cheng-Mao Cheng ◽  
Akio Noguchi ◽  
...  
Keyword(s):  
Mouth Opening ◽  
Anatomical Study ◽  
Craniocervical Junction ◽  
Surgical Approaches ◽  
Le Fort I Osteotomy ◽  
Le Fort ◽  
Anatomical Analysis ◽  
Stereotactic Localization ◽  
Good Exposure ◽  
Le Fort I

Object The authors conducted a cadaveric anatomical study to quantify and compare the area of surgical exposure and the freedom available for instrument manipulation provided by the following four surgical approaches to the extracranial periclival region: simple transoral (STO), transoral with a palate split (TOPS), Le Fort I osteotomy (LFO), and median labioglossomandibulotomy (MLM). Methods Twelve unembalmed cadaveric heads with normal mouth opening capacity were serially dissected. For each approach, quantitation of extracranial periclival exposure and freedom for instrument manipulation (known here as surgical freedom) was accomplished by stereotactic localization. To quantify the extent of extracranial clival exposure obtained, anatomical measurements of the extracranial clivus were performed on 17 dry skull bases. The values (means ± standard deviations in mm2) for periclival exposure and surgical freedom, respectively, for the surgical approaches studied were as follows: STO = 492 ± 229 and 3164 ± 1900; TOPS = 743 ± 319 and 3478 ± 2363; LFO = 689 ± 248 and 2760 ± 1922; and MLM 1312 ± 384 and 8074 ± 6451. The extent of linear midline clival exposure and the percentage of linear midline clival exposure relative to the total linear midline exposure were as follows, respectively: STO = 0.6 ± 4.9 mm and 7.8 ± 11%; TOPS = 8.9 ± 5.5 mm and 24.2 ± 16.7%; LFO = 32.9 ± 10.2 mm and 85.0 ± 18.7%; and MLM = 2.1 ± 4.4 mm and 6.7 ± 11.1%. Conclusions The choice of approach and the resulting degree of complexity and associated morbidity depends on the location of the pathological entity. The authors found that the MLM approach, like the STO approach, provided good exposure of the craniocervical junction but limited exposure of the clivus. The TOPS approach, an approach attended by a lesser risk of morbidity, provided adequate exposure of the extracranial inferior clivus. Maximal exposure of the extracranial clivus proper was provided by the LFO approach.

Drilling the posterior wall of the petrous pyramid: a microneurosurgical anatomical study

1993 ◽  
Vol 78 (3) ◽  
pp. 452-455 ◽  
Author(s):  
Mario Ammirati ◽  
Jianya Ma ◽  
Melvin L. Cheatham ◽  
David Maxwell ◽  
Joseph Bloch ◽  
...  
Keyword(s):  
Inner Ear ◽  
Internal Auditory Canal ◽  
Anatomical Study ◽  
Posterior Wall ◽  
Anterior Portion ◽  
Content Type ◽  
Vestibular Aqueduct ◽  
Drilling Technique ◽  
Minimum Depth ◽  
Horizontal Portion

✓ Posterior approaches to the petroclival area requiring extensive drilling of the posterior pyramidal wall have been described in the last 10 years. If hearing is to be preserved, damage to the inner-ear structures must be avoided; however, the fine points of this pyramidal drilling technique have never been reported in detail. A microneurosurgical anatomical study was undertaken in 15 cadavers to determine the relationships between bone landmarks and labyrinthine structures that could be used to give some practical drilling guidelines. Drilling of the posterior pyramidal wall is facilitated on identification of the intersection of the petrous ridge with the most anterior portion of the bone ledge covering the sigmoid sinus (petrosigmoid intersection), the bony operculum of the endolymphatic sac, and the petrous ridge. Drilling may proceed rather safely at a minimum depth of 2.5 mm in an area 0.9 cm anterior and 1 cm inferior to the petrosigmoid intersection and petrous ridge, respectively. From there, identification of the vestibular aqueduct, genu, and horizontal portion is necessary to safely open the posterior wall of the internal auditory canal. The vestibular aqueduct represents the lateral and superior limits of drilling. The bone between these areas may then be safely drilled to a depth of at least 2.5 mm. A microneurosurgical dissection of the posterior pyramidal wall conducted in cadaveric material according to these guidelines did not violate any inner-ear structures.

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