TEACHING ANATOMY

Endoscopic anatomy and approaches of the cavernous sinus:cadaver study

Bashar Abuzayed • Necmettin Tanriover • Nurperi Gazioglu •

Fatma Ozlen • Gursel Cetin • Ziya Akar

Received: 2 May 2009 / Accepted: 15 October 2009 / Published online: 29 April 2010

� Springer-Verlag 2010

Abstract

Objective The objectives of this study were to recognize

the endoscopic anatomy of the cavernous sinus and to

understand the standard, purely endoscopic endonasal

approaches to this anatomic structure. This basic infor-

mation will facilitate our surgical procedures and decrease

the rate of surgical complications.

Materials and methods Seven fresh adult cadavers were

studied bilaterally (n = 14). We used Karl Storz 0 and 30�,

4 mm, 18 cm and 30 cm rod lens rigid endoscope in our

dissections. After cadaver preparation, extended endo-

scopic endonasal approaches were performed to access the

cavernous sinus.

Results In the seven cadavers, the cavernous sinus and

superior orbital fissure, on both sides, were widely exposed

with extended endoscopic endonasal approach. The antero-

inferior portion of the cavernous sinus was exposed by

removing the superior and the middle turbinates and the

posterior ethmoidal cells (extended endoscopic endonasal

transsphenoidal approach); the whole lateral wall of the

cavernous sinus was exposed by removing the anterior and

the posterior ethmoidal cells (endonasal ethmoido-pterygo-

sphenoidal approach: far lateral); and the medial wall of the

cavernous sinus was exposed by introducing the 30� endo-

scope from the contralateral nostril (contralateral endoscopic

endonasal transsphenoidal approach). According to the

neurovascular architecture, the lateral wall of the cavernous

sinus is divided into the superior triangular area, the superior

quadrangular area and the inferior quadrangular area. This

division can facilitate understanding of the anatomic rela-

tions of the cavernous sinus from the endoscopic view.

Conclusion Knowledge of the anatomy of the cavernous

sinus obtained with an endoscopic view of cadaver dis-

sections is an essential step in the learning curve of

endoscopic skull base surgery, and is important for endo-

scopic treatment of various pathologies in this region. In

this anatomic study, we reviewed the approaches to the

cavernous sinus with an endoscopic view and identified the

neurovascular relations. This approach will help in per-

forming safer and minimally invasive surgery.

Keywords Endoscopic endonasal approach �Cavernous sinus � Surgical anatomy

Introduction

The cavernous sinus has a complex anatomy, with impor-

tant related neurovascular structures. Knowledge of this

architecture is essential to perform effective and safe sur-

gery in this region. For this reason, many anatomic studies

were performed to define the surgical anatomy and

approaches to the cavernous sinus [16, 17, 32, 36–38]. With

the introduction of the endoscopic endonasal transsphe-

noidal surgery of the pituitary gland [5, 8, 12–14, 25], many

modifications and approaches were developed to provide a

wider surgical view, including exposure of the cavernous

sinus [6, 7, 9, 11, 20] and, more recently, to remove tumors

located within the cavernous sinus [19, 21, 26].

In the extended endoscopic endonasal transsphenoidal

surgery, the endoscope allows wide exposure of the sellar

B. Abuzayed (&) � N. Tanriover � N. Gazioglu � F. Ozlen �Z. Akar

Department of Neurosurgery, Cerrahpasa Medical Faculty,

Istanbul University, Istanbul, Turkey

e-mail: sylvius@live.com

G. Cetin

Morgue Specialization Department, Forensic Medicine Institute,

Ministry of Justice, Istanbul, Turkey

123

Surg Radiol Anat (2010) 32:499–508

DOI 10.1007/s00276-010-0651-3

and the parasellar areas, such as the sphenoidal planum, the

clivus, and the optic and carotid protuberances [1–5]. The

aim of this study was to recognize the endoscopic anatomy

of the cavernous sinus and to understand the standard,

purely endoscopic endonasal approaches to this anatomic

structure. This will help us to understand the neurovascular

relations and perform safe and controlled surgery, thus

decreasing the rate of surgical complications.

Materials and methods

Seven fresh adult cadavers were studied and bilateral endo-

scopic endonasal approach to the cavernous sinus was per-

formed (n = 14). Endoscopic dissections were performed at

the Turkish Republic, Ministry of Justice, Forensic Medicine

Institute, Morgue Specialization Department. The selection

criteria were: (1) age of 18 years or older, (2) no history of

head trauma or craniofacial surgery and (3) dissection of

corpses that had already been autopsied or during autopsy

(dissection was not done before the evaluation and permission

of the forensic medicine doctors). Dissection was performed

using Karl Storz 0� and 30�, 4 mm, 18 cm and 30 cm rod lens

rigid endoscope (Karl Storz and Co., Tuttlingen, Germany).

The endoscope was connected to a light source via a fiberoptic

cable and to a camera fitted with three-charge-coupled devices

sensors. The video camera was connected to a 21-inch mon-

itor. As surgical instrumentation, we used the Karl Storz

Kassam-Snydermann endoscopic surgical set. The cadaveric

specimen was placed in a supine position with the head in a

neutral position and 10–15� adducted toward the left shoulder.

Dissection technique

The endoscope is introduced into the right nostril. The

choana is identified in the postero-inferior end of the nasal

cavity, at the end of the tail of the inferior turbinte and

medially to the vomer. The endoscope is directed rostrally

along the sphenoethmoidal recess, and the sphenoid ostium

is exposed nearly 15 mm superior to the choana, between

the superior turbinate and the nasal septum [5]. The middle

turbinate is resected to gain wider exposure and a more

comfortable surgical corridor. The mucosa is dissected

laterally and medially by the endoscopic dissector to

expose the sphenoid sinus floor and anterior wall and

medially the rostrum. The posterior part of the nasal sep-

tum is resected from the rostrum, and the septal mucosa of

the left nasal cavity is visualized. The dissector is passed

between the rostrum and the fractured nasal septum to

reach the left nasal mucosa, which is dissected from the left

side of the rostrum and the left sphenoid floor. In this way,

the entire sphenoid sinus floor and the ostia are exposed

(Fig. 1a). A similar procedure is performed from the left

nostril, except that the left middle turbinate is lateralized.

In this way, dissection is continued by the binostril

approach. The rostrum is fractured and with a 2-mm high

speed drill or 2-mm Karrison ronguer, the right ostium is

widened and the inferior and anterior walls of the sphenoid

sinus are resected (anterior sphenoidectomy). During the

resection of the inferior and anterior sphenoid sinus walls

toward lateral direction, care must be taken not to injure the

vidian nerve (the sphenopalatine nerve) and the spheno-

palatine artery. The sphenopalatine artery is located in the

infero-lateral corner to the sphenoid sinus and 1 cm ante-

rior to the rear end of the tail of the middle turbinate in

90% of cases [31]. The septae in the sphenoid sinus and

sinus mucosa are removed by the endoscopic punch

exposing the sellar floor and its anatomic landmarks

(Fig. 1b and c).

At the center of the sellar floor, the sellar fossa is iden-

tified. Rostrally to the sellar fossa, the planum sphenoidale

is identified. Supero-laterally to the sellar fossa and laterally

to the planum sphenoidale, the optic protuberances are

identified on both sides. Laterally to the sellar fossa, the

carotid protuberance is identified with its two parts: supe-

riorly the sellar carotid protuberance and inferiorly the

clival carotid protuberance. Between the optic and carotid

protuberance, the opticocarotid recess, which represents the

base of the anterior clinoid processes, is identified. Lateral

septae generally point to the opticocarotid recess, which is

the reason why these are good anatomic landmarks during

dissection [4, 5] (Fig. 1b). The sellar fossa is fractured by a

sharp dissector and widened by a 2-mm Karrison ronguer to

expose the sellar dura (Fig. 1d).

The inferior portion of cavernous sinus is exposed by

removing the superior and the middle turbinates and the

posterior ethmoidal cells (extended endoscopic endonasal

transsphenoidal approach) (Fig. 2a). To expose the whole

lateral wall of the cavernous sinus, the uncinate process is

resected. After identifying the ethmoid bulla, it is opened

and the anterior and then the posterior ethmoidal cells are

exposed and removed (endonasal ethmoido-pterygo-sphe-

noidal approach) (Fig. 2b). The medial wall of the cav-

ernous sinus is exposed by a 30� endoscope introduced

through the contralateral nostril (contralateral endoscopic

endonasal transsphenoidal approach) (Fig. 2c) [9, 21].

Results

Cadaveric specimens were placed in a supine position with

the head in the neutral position and 10–15� adducted

toward the left shoulder. We found this position to be more

suitable for the surgeon, as it does not disturb the surgical

orientation and avoids lateral bending of the surgeon’s

500 Surg Radiol Anat (2010) 32:499–508

123

Fig. 2 Axial paranasal CT

scans demonstrating the

approaches and related areas of

exposure of the cavernous sinus.

a Extended endoscopic

endonasal transsphenoidal

approach; b endonasal

ethmoido-pterygo-sphenoidal

approach (far lateral).c Contralateral endoscopic

endonasal transsphenoidal

approach

Fig. 1 a Endoscopic view of

the exposed anterior sphenoid

sinus and ostia. b Endoscopic

view after anterior

sphenoidectomy, exposing

the landmarks of the roof of

the sphenoid sinus. Note that the

lateral septae of the cavernous

sinus are located under the

carotid protuberances, and thus

considered as a good landmark.

c A schematic representation of

the anatomical landmarks in the

roof of the sphenoid sinus.

d Endoscopic view of the

pituitary gland exposure after

sellar floor resection. C clivus,

CPc clival part of the carotid

protuberance, CPs sellar part of

the carotid protuberance, ICA-Aanterior bend of the internal

carotid artery, NS nasal septum,

OP optic protuberance,

PG pituitary gland, PS planum

sphenoidale, R rostrum,

SF sellar floor, SICS superior

intercavernous sinus,

SO sphenoid ostium

Surg Radiol Anat (2010) 32:499–508 501

123

trunk toward the patient, thus causing less fatigue during

the surgical procedures [1–5].

The antero-inferior part of the cavernous sinus

The sellar floor is resected laterally toward the carotid

protuberance to expose the parasellar portion of the internal

carotid artery (ICA). This resection is continued laterally

until the lateral border of ICA, thus exposing the inferior

part of the cavernous sinus (Fig. 3). Both the anterior and

the posterior bends of the parasellar portion of ICA are

widely exposed.

The lateral part of the cavernous sinus

After exposure of the bone of the inferior part of the cav-

ernous sinus and the middle cranial fossa (Fig. 4a), bone

resection is continued laterally from the lateral border of

the parasellar ICA until the level of the pterygoid apex. In

this way, the whole lateral part of the cavernous sinus,

including the oculomotor nerve (CNIII), ophthalmic nerve

(CNV1), maxillary nerve (CNV2) and mandibular nerve

(CNV3), with the course of the abducens nerve (CNVI), are

exposed (Fig. 4b). The vidian nerve (the sphenopalatine

nerve) exits from the vidian canal, which is located in the

pterygoid base, inferior to the ICA segment between the

vertical paraclival segment and horizontal petrous segment

(lacerum segment) [27]. Thus, the vidian nerve is a good

landmark locating the lacerum segment of ICA at the

turning point between the paraclival and the petrous por-

tions [19–21, 27]. When the opening of the vidian canal is

required to expose the vidian nerve and/or approaching

pathologies in the pterygopalatine fossa, drilling of the

canal is recommended to be started from the inferior and

medial aspect of the canal, as ICA is located along the

superior margin [27]. This will decrease the risk of intra-

operative injury of ICA during drilling of the vidian canal.

After identifying the vidian nerve, a triangular area lateral

to ICA can be identified. The base of this triangle is formed

Fig. 3 Endoscopic view after extended endonasal transsphenoidal

approach to expose the inferior part of the both cavernous sinuses.

C clivus, ICA-A anterior bend of the internal carotid artery, ICA-Pposterior bend of the internal carotid artery, ICA-c paraclival part of

the internal carotid artery, ON optic nerve, PE planum ethmoidale,

PG pituitary gland

Fig. 4 a Endoscopic view of the bone of the inferior part of the right

cavernous sinus and right middle cranial base after the endonasal

ethmoido-pterygo-sphenoidal approach. b The right cavernous sinus

and its neurovascular relations are exposed after bone resection. IIIoculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend

of the internal carotid artery–parasellar segment, ICA-Sp posterior

bend of the internal carotid artery–parasellar segment, ICA-Cparaclival segment of the internal carotid artery, ICA-L lacerum

segment of the internal carotid artery, ICA-P petrous segment of the

internal carotid artery, P pterygoid base, PG pituitary gland, VCvidian canal, VN vidian nerve

502 Surg Radiol Anat (2010) 32:499–508

123

by the vidian nerve inferiorly with the apex pointing

superiorly. The lateral arm of the triangle is formed by the

medial pterygoid process, and the medial arm is formed by

the parasellar ICA (Fig. 5). After dissecting the dura cov-

ering the triangular area, the oculomotor (CNIII), abducens

(CNVI) and maxillary (CNV2) nerves are visualized and

together they form an ‘S’ shape (Fig. 6). This is another

useful landmark configuration, which helps to identify the

cranial nerves in the cavernous sinus [9]. The trochlear

nerve (CNIV) is located behind this complex and could be

exposed by retracting the oculomotor nerve (Fig. 7).

The lateral cavernous sinus areas [9] are identified. This

can be facilitated by retracting ICA medially (Fig. 8):

1. Superior triangular area (STA): the base of this area is

formed by the lateral loop of ICA. The superior border

is formed by CNIII and the inferior border by CN VI.

This area contains CNIV.

2. Superior quadrangular area (SQA): this area is bor-

dered superiorly by CNVI, inferiorly by CNV2, medi-

ally by ICA and laterally by the bone of the lateral wall

of the sphenoid sinus, which extends from SOF to the

foramen rotundum. This area contains CNV1.

3. Inferior quadrangular area (IQA): this area is bordered

by CNV2 superiorly, the vidian nerve inferiorly,

interpetrous segment of ICA medially and the

sphenoid bone extending from the foramen rotundum

and pterygoid canal laterally. This area is extensively

external to the cavernous sinus.

By retracting the ICA and CNIV medially away from the

lateral wall of the cavernous sinus, a quadrangular area,

bordered superiorly by the CNVI, inferiorly by the petrous

segment of ICA, medially by the paraclival segment of ICA

and laterally by CNV2, is exposed. This area represents the

anterior part (door) of the Meckel’s cave [27] (Fig. 9).

The medial part of the cavernous sinus

After the exposure of the area between the parasellar ICA

and the pituitary gland, an arachnoid band connecting the

anterolateral surface of the pituitary gland and the anterior

bend of the parasellar ICA is visualized and resected

(Fig. 10). From the contralateral nostril, the 30� endoscope

is introduced. The pituitary gland is retracted medially and

the medial wall of the cavernous sinus and the inferior

Fig. 5 Endoscopic view of the right cavernous sinus and its

neurovascular relations, demonstrating the triangular area formed

by the medial pterygoid process laterally, the parasellar ICA medially

and the vidian nerve inferiorly at the base. III oculomotor nerve, V1ophthalmic nerve, V2 maxillary nerve, V3 mandibular nerve, VIabducens nerve, C clivus, ICA-Sa anterior bend of the internal carotid

artery–parasellar segment, ICA-Sp posterior bend of the internal

carotid artery–parasellar segment, ICA-C paraclival segment of the

internal carotid artery, ICA-L lacerum segment of the internal carotid

artery, ICA-P petrous segment of the internal carotid artery, PGpituitary gland, VC vidian canal, VN vidian nerve

Fig. 6 Endoscopic view of the right cavernous sinus and neurovas-

cular relations, demonstrating the ‘S’ shaped configuration formed by

the oculomotor, the abducens and the vidian nerves. III oculomotor

nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular

nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the

internal carotid artery–parasellar segment, ICA-Sp posterior bend of

the internal carotid artery–parasellar segment, ICA-C paraclival

segment of the internal carotid artery, ICA-L lacerum segment of

the internal carotid artery, ICA-P petrous segment of the internal

carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve

Surg Radiol Anat (2010) 32:499–508 503

123

hypophyseal artery (IHA) are exposed (Fig. 11a). The

endoscope is advanced inferior to the pituitary gland and

the inferior hypophyseal artery, and the posterior aspect of

the sellar fossa and the posterior clinoid process are

exposed (Fig. 11b).

Discussion

The cavernous sinus is a complicated structure with a

unique architecture. Thus, detailed anatomic knowledge

is necessary for surgical intervention in this region.

Transcranial and/or transfacial approaches are considered

invasive, with unwanted brain retraction and difficulty in

exposing the medial part of the cavernous sinus. To

overcome this problem, different transsphenoidal

[22–24], transmaxillary [10], transmaxillosphenoidal

[35], transethmoidal [11] and transsphenoethmoid [30]

approaches have been described for removal of lesions

located in the anterior portion of the cavernous sinus.

However, these approaches still have their limitations and

drawbacks, such as the narrow straight surgical corridor,

with limited exposure. With the introduction of the

endoscopic endonasal transsphenoidal surgery to the

pituitary gland [5, 8, 12–14, 25], wide endoscopic expo-

sure offered the ability to reach the cavernous sinus by

this route. Recently, anatomic reports have studied the

endoscopic anatomy and approaches of the cavernous

Fig. 7 Endoscopic view (a),

and a drawing (b) of the right

cavernous sinus demonstrating

its neurovascular relations.

c A drawing of the right

cavernous sinus demonstrating

the exposure of the trochlear

nerve after retracting the

oculomotor nerve. IIIoculomotor nerve, IV trochlear

nerve, V1 ophthalmic nerve,

VI abducens nerve, ICA internal

carotid artery, OA ophthalmic

artery, OCh optic chiasm, ONoptic nerve, PG pituitary gland

Fig. 8 Endoscopic view of the right cavernous sinus showing its

neurovascular relations and the main anatomic areas. III oculomotor

nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular

nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the

internal carotid artery–parasellar segment, ICA-Sp posterior bend of

the internal carotid artery–parasellar segment, ICA-C paraclival

segment of the internal carotid artery, ICA-L lacerum segment of

the internal carotid artery, ICA-P petrous segment of the internal

carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve,

STA superior triangular area, SQA superior quadrangular area, IQAinferior quadrangular area

504 Surg Radiol Anat (2010) 32:499–508

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sinus [6, 7, 9, 10, 20]. These reports defined surgical

corridors to reach different areas of the cavernous sinus.

The anatomic landmarks of the roof of the sphenoid sinus

and their relations to the cavernous sinus have been

highlighted. The intercavernous segment of ICA has been

classified in relation to the pituitary gland (parasellar

Fig. 9 a Endoscopic view of the right cavernous sinus showing its

neurovascular relations after retracting the internal carotid artery

medially. b Internal carotid artery and the abducens nerve are both

retracted medially to expose the lateral wall of the cavernous sinus

and the anterior part of Meckel’s cave (dotted area). III oculomotor

nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular

nerve, VI abducens nerve, C clivus, ICA internal carotid artery,

SF sympathetic fibers, VC vidian canal

Fig. 10 a Endoscopic view of

the left arachnoid band

connecting the anterolateral

surface of the pituitary gland

and the anterior bend of the left

parasellar IC. b Medial wall of

the left cavernous sinus is

exposed after the resection of

the band. B band, C clivus, CSmmedial wall of the cavernous

sinus, ICA-A anterior bend

of the internal carotid artery,

ICA-P posterior bend of the

internal carotid artery,

PG pituitary gland

Fig. 11 a Endoscopic view of

the medial wall of the left

cavernous sinus after retracting

the pituitary gland to the right

side. The left inferior

hypophyseal artery is exposed.

b The endoscope is advanced

inferior to the left inferior

hypophyseal artery and the left

side of the pituitary gland to

expose the anterior surface of

the left posterior clinoid

process. ICA internal carotid

artery, IHA inferior hypophyseal

artery, PC posterior clinoid

process, PG pituitary gland

Surg Radiol Anat (2010) 32:499–508 505

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ICA) and clivus (paraclival ICA), which is found to be

more appropriate for endoscopic approaches [7].

In our study, we highlighted the important structures and

landmarks, from the endoscopic view, which will help us to

understand the neurovascular relations of the cavernous sinus.

Based on the anatomical information provided, appropriate

surgical approach with defined surgical corridors can be

selected for different areas of the cavernous sinus.

To expose the inferior portion of the cavernous sinus,

the superior and the middle turbinates and the posterior

ethmoidal cells are removed (extended endoscopic endo-

nasal transsphenoidal approach). The anatomic landmarks

in the roof of the sphenoid sinus are valuable to determine

the anatomic location of the cavernous sinus. ICA, with its

parasellar and paraclival parts, is delineated by the carotid

protuberance, with the sellar fossa located medially. Also,

when the lateral septae of the sphenoid sinus exist, these

are generally attached to the carotid protuberance and point

to the location of ICA [5]. These important landmarks can

help locate the intercavernous ICA and the cavernous sinus

before bone resection and opening of the dura, which offers

a safer approach [7]. Including the sellar fossa in the bone

resection is preferred, as wide exposure of the related

structures avoid blind manipulation and create a space for

ICA retraction when needed.

The lateral wall of the cavernous sinus is exposed by the

endonasal ethmoido-pterygo-sphenoidal approach [21]. In

this approach, the uncinate process is resected and, after

identifying the ethmoid bulla, the bulla is opened, and the

anterior and then the posterior ethmoidal cells are exposed

and removed. Inside this area, another three areas are

delineated: the superior triangular area, the superior qua-

drangular area, the quadrangular inferior area and a narrow

C-shaped area located medial to ICA [9]. This approach is

suitable especially for lesions involving the area between

ICA and the cranial nerves of the cavernous sinus, as these

lesions are reached directly without the need to pass

through the cranial nerves, in contrast to transcranial

microsurgical approaches.

To expose the medial wall of the cavernous sinus, an

arachnoid band connecting the anterolateral surface of the

pituitary gland and the anterior bend of the parasellar ICA

is resected. From our dissections, we believe that this

band can be a medial extension of the proximal carotid

ring. The medial part of the cavernous sinus is exposed by

the 30� endoscope, introduced through the contralateral

nostril (contralateral endoscopic endonasal transsphenoi-

dal approach). In contrast to microsurgical transcranial

approaches, endoscopic endonasal approaches offer direct

exposure of the medial part of the cavernous sinus,

without the need to pass through the cranial nerves and

ICA. This avoids possible injury to these structures due to

surgical manipulation.

The logic of the infero-medial approaches to the cav-

ernous sinus is based on the following anatomic and sur-

gical observations mentioned by Cavallo et al. [9]:

1. The meningeal wall of the cavernous sinus has three

weak points, through which tumor invasion and

extension is favorable: the venous plexus around the

SOF, the loose texture of the medial wall around the

pituitary body and the dural pockets of the cranial

nerves. The dural wall is extremely thin or absent at

those points [28].

2. The medial wall of the cavernous sinus is formed only

by one continuous thin layer of dura, in contrast to the

lateral and the superior walls, which are formed by two

(meningeal and endosteal) layers [39]. The thin dura in

the medial wall may be incomplete [18] or absent

[15, 29].

3. Venous compartments around the intercavernous

carotid can be differentiated into various sizes and

shapes. From the superior view, the venous space

medial to the ICA is dominant in 48 versus 22% in

which the venous space lateral to the ICA is dominant

[33, 34]. From the lateral view, the venous space

antero-inferior to the ICA is dominant in 60% of cases,

whereas the venous space posterosuperior to the ICA is

dominant in only 16% of the cases [24].

4. The pituitary gland can overlap the intracavernous

carotid artery with a tongue-like projection [34].

These anatomic observations can explain, as recently

reported, the reason why most nonfunctioning pituitary

adenomas extending into the cavernous sinus are neither

aggressive nor invasive [40], but are only growing lesions

through the weak points of the wall of the cavernous sinus.

This growth pattern of the tumors results in enlarging and

widening of the anatomic planes between the cavernous

sinus and the neighboring structures, or between the

intercavernous structures themselves, thus creating a wide

surgical corridor and easier exposure of the pathology.

Recently, Kassam et al. [27] have described the exposure

of the anterior part, door of the Meckel’s cave, by

retracting the ICA and CNIV medially away from the lat-

eral wall of the cavernous sinus. This entrance area to the

Meckel’s cave is bordered superiorly by the CNVI, infe-

riorly by the petrous segment of ICA, medially by the

paraclival segment of ICA and laterally by CNV2. This

approach provides a good access to tumors located or

invading the Meckel’s cave [27].

The main problem in the endoscopic approach is con-

trolling bleeding after incidental injury of ICA. Also,

bleeding from the cavernous sinus, especially after

removing the tumor and decompressing the sinus, can be

problematic. However, sinus bleeding can be controlled

with proper materials for hemostasis. Another potential

506 Surg Radiol Anat (2010) 32:499–508

123

complication is the injury to the cranial nerves. However,

the endoscopic approach is more superior in protecting the

cranial nerves, as with the infero-medial the medial part of

the cavernous sinus can be reached directly, without the

need to dissect and pass through the cranial nerves.

Conclusions

Knowledge of the anatomy of the cavernous sinus obtained

with an endoscopic view of cadaver dissections is impor-

tant for endoscopic treatment of various the pathologies of

this region. In this study, we reviewed the endoscopic

anatomy of the cavernous sinus and the related neurovas-

cular structures. Based on these anatomic findings, we

described the appropriate endoscopic surgical approaches

to the different parts of the cavernous sinus. This anatomic

knowledge is important to perform a safer and minimally

invasive surgery.

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