Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4368_Библиотеки_им_академика_М_И_Перельмана
.pdf
AN
https://t.me/med1917
Frontal Sinus and Draf Approaches
NS
SS
a
O
d
MS
LP
LP
b
O
AN
e
MT
NS
c
f
AN
MT
AN
MT
g
Fig. 4.8 (a) Endoscopic view of a cadaveric dissection on the left side. The ascending process of the maxilla is denuded up to the
agger nasi. The dissector points at the level of the olfactory cleft where the mucosal incision has to be made to identify the fi rst
olfactory fi ber. Arrow, middle turbinate; *lacrimal sac (partially exposed); rectangle, olfactory cleft; AN, agger nasi; MS, maxillary sinus
opening; short arrow, posterior ethmoidal artery; SS, sphenoid sinus. (b) Endoscopic view of the dissection of the fi rst olfactory fi ber in
the olfactory cleft. NS, nasal septum; arrow pointing at the bony cleft of the fi rst olfactory fi ber. O, showing the incision of the mucosa
and subperiosteal dissection to create a mucosal fl ap that can be used at the end to cover denuded bone of the posterior wall of the
frontal sinus after the drilling. The same steps can be performed on the contralateral side to provide two fl aps. (c) Endoscopic view
with a 45-degree lens. Arrow points at the fi rst olfactory fi ber as the most posterior limit of dissection. The nasal septum anteriorly to
that point is resected (o, resection borders). A backbiting forceps can be used to create this nasal window. Inferiorly, the anterior edge
of the middle turbinate represents the posterior limit of the partial septectomy. This maneuver also allows us to work with the fourhand technique. The head of the middle turbinate can be removed to obtain a better exposure, but it is not always necessary. Drilling
of the remnant perpendicular plate of the ethmoid and the fl oor of the frontal sinus can be started anteriorly to the fi rst olfactory
fi bers on both sides, as delineated by the quadrangle. Curved drills are helpful. They allow a more superior reach into the frontal sinus
as well as a more comfortable drilling of the nasofrontal beak.
(d) The curved drill has partially removed the fl oor of the frontal sinus, revealing both frontal sinuses and the interfrontal septum
(O). Arrows point at both fi rst olfactory fi bers as the posterior limit of the drilling. (e) Both frontal sinuses have been opened; the
interfrontal sinus wall (O) still needs some drilling. Arrows point at the fi rst olfactory fi bers on both sides. AN, left agger nasi; MT, left
middle turbinate. (f) Now, the agger nasi (AN) can be drilled in order to communicate the frontal recess with the frontal recess. MT,
middle turbinate; arrows point at the fi rst olfactory fi bers. O, depicts area to be drilled (bilaterally) to achieve a large “T”-like opening.
(g) Drilling of the agger nasi has progressed, the frontal recess (*) widely open. The lateral limits are the lacrimal sac (inferiorly) and
the lamina papyracea superiorly. Anteriorly, after drilling the nasofrontal beak, its external mucoperiosteum can be exposed. Arrows,
fi rst olfactory fi bers; LP, lamina papyracea; MT, middle turbinate; o, area to be resected. (h) Situation after bilateral drilling of the
frontal sinuses as seen with a 45-degree lens. The interfrontal sinus wall has been removed subtotally; both sinuses are interconnected
as a single cavity and open toward the nose in a large “T”-shaped fashion.
MT
h
10
AN, (denuded) agger nasi; MT, middle turbinate; NS, nasal septum.
45
Frontal Sinus and Draf Approaches
https://t.me/med1917
a b
46
c
Fig. 4.9 (a) Preoperative sagittal MRI T1-weighted gadolinium-enhanced studies revealed an extra-axial enhancing benign lesion
located in the nasal cavity and protruding into the anterior cranial fossa. Note the extension of the lesion along the anterior cranial
base reaching the planum sphenoidale. (b) Same preoperative MRI T1-weighted gadolinium-enhanced imaging in an axial plane.
Please note the lateral expansion and displacement of the left medial rectus muscle without infi ltration of the orbital content and a
secondary right sphenoidal sinusitis.
(c) Intraoperative picture of a Draf type III procedure that allows a better exposure of the anterior skull base and proper delimitation of
landmarks to perform a transcribriform approach (not depicted here). It also ensures a proper frontal sinus drainage and aeration.
Frontal Sinus and Draf Approaches
https://t.me/med1917
NFB
PWFS
NS
OC
LP
LP
a
b
NFB
NS
CP
c
d
Fig. 4.10 (a) Preoperative MRI T1-weighted gadolinium-enhanced coronal imaging revealing a heterogeneous and hyperenhanced
lesion located in the nasal cavity. (b) Intraoperative image of the anterior endonasal cranial base resection after a Draf type IIb.
LP, lamina papyracea; NFB, nasofrontal beak; NS, nasal septum; OC, olfactory cleft; PWFS, posterior wall of the frontal sinus.
(c) Intraoperative image showing the olfactory cleft fully exposed. CP, cribriform plate; NFB, nasofrontal beak; NS, nasal septum.
(d) Immediate postoperative coronal and sagittal T1-weighted gadolinium-enhanced MRI showing total tumor removal and wide
frontal sinus communication with the nasal cavity. In the coronal image, please note the intact lamina papyracea.
References
1. Park SS, Yoon BN, Cho KS, Roh HJ. Pneumatization pattern of the
frontal recess: relationship of the anterior-to-posterior length of
frontal isthmus and/or frontal recess with the volume of agger
nasi cell. Clin Exp Otorhinolaryngol 2010;3(2):76–83
2. Kew J, Rees G, Close D, Sdralis T, Sebben R, Wormald PJ. Multiplanar reconstructed computed tomography images improves depiction and understanding of the anatomy of the frontal sinus and
recess. Am J Rhinol 2002;16(2):119–123
3. Stammberger H, Hasler G. Functional Endoscopic Sinus Surgery:
The Messerklinger Technique. Philadelphia, PA: Decker; 1991
4. Wormald PJ, Hoseman W, Callejas C, et al. The International
Frontal Sinus Anatomy Classification (IFAC) and classification of
the extent of Endoscopic Frontal Sinus Surgery (EFSS). Int Forum
Allergy Rhinol 2016;6(7):677–696
5. Wormald PJ. Surgery of the frontal recess and frontal sinus.
Rhinology 2005;43(2):82–85
6. Minni A, Messineo D, Attanasio G, Pianura E, D’Ambrosio F.
3D cone beam (CBCT) in evaluation of frontal recess: findings
in youth population. Eur Rev Med Pharmacol Sci 2012;16(7):
912–918
7. Mahmutoğlu AS, Çelebi I, Akdana B, et al. Computed tomographic
analysis of frontal sinus drainage pathway variations and frontal
rhinosinusitis. J Craniofac Surg 2015;26(1):87–90
8. Huang BY, Lloyd KM, DelGaudio JM, Jablonowski E, Hudgins PA.
Failed endoscopic sinus surgery: spectrum of CT findings in the
frontal recess. Radiographics 2009;29:177–195
9. Kountakis SE, Senior BA, Draf W. Endonasal frontal sinus drainage type I–III according to Draf. In: Kountakis SE, Senior BA,
Draf W, eds. The Frontal Sinus. New York, NY: Springer; 2005;
219–232
10. Al Komser MK, Goldberg AN. Unilateral transnasal endoscopic
approach to frontal sinuses: Draf IIc. Allergy Rhinol (Providence)
2013;4:e82–e87
47
https://t.me/med1917
Chapter 5
https://t.me/med1917
5.1 Anatomy of the Sphenoid Sinus 50
Sphenoid Sinus
5.2 Preoperative Evaluation 52
5.3 Indications 53
5.4 Surgical Steps 53
5.5 Case Examples 55
5.6 Complications 55
5.7 Tips and Tricks 55
Sphenoid Sinus
https://t.me/med1917
5 Sphenoid Sinus
Eduardo Lehrer, Isam Alobid, Arturo Cordero Castillo, Manuel Bernal-Sprekelsen
Introduction
The sphenoid sinus is the deepest cell of all paranasal
sinuses. Its correct opening becomes essential when
there is sphenoid disease or when exposing the middle or posterior skull base. Care must be taken not to
damage the optic nerves, the carotid arteries, or the
pituitary gland, among other noble structures, to avoid
major complications. This chapter concentrates on the
surgical anatomy of the sphenoid sinus, preoperative
imaging evaluation, surgical approaches detailed step by
step, and potential complications and how to avoid them
during surgery.
The intricacy of the anatomy of the paranasal sinuses
lies in its great variability between subjects. In this sense,
the sphenoid sinus is not an exception.
The sphenoid sinus (from modern Latin sphenoides,
referring to “wedge”) is located in the middle of the
skull. Every single sphenoid sinus wall is in touch with
important structures: the lateral walls cover the internal
carotid arteries, above these the optic nerves, the cavernous sinus, and all its relations with the third, fourth, fifth,
and sixth cranial nerves.
5.1 Anatomy of the Sphenoid
Sinus
The sphenoid sinus appears during the second to third
years of life when the cartilage corresponding to the
ossiculum Bertini attaches to the sphenoid bone and
starts pneumatization. Progressively, the sphenoid sinus
continues its aeration during the age of 9 to 12 years (and
above) and expands laterally, posteriorly, and inferiorly
until obtaining the ratio observed in the adult
The sphenoid sinus is sculpted into the clivus and is enclosed superiorly and posteriorly by the sella turcica. Together with posterior ethmoid cells, the sphenoid ostium
drains into the sphenoethmoidal recess located beneath
the superior turbinate from which mucus passes to the
nasopharynx.
A bony vertical septum divides the sinus into two, mostly asymmetric sinuses. This septum is highly variable and
can be oriented not only on a vertical plane. When the septum extends more laterally, it usually ends up attached to
the internal carotid arteries. This is the reason it is recommended to drill those septa and not fracture them.
1
(Fig. 5.1).
ON
OE
e
Fig. 5.1 Sagittal view of pneumatized sphenoid sinus in a fresh cadaver. Please note the close relation between each structure and
the thin bone layer between them. CA, internal carotid artery; e, posterior ethmoidal cell; H, pituitary gland; OE, ostium sphenoidale
or sphenoethmoidal recess; ON, optic nerve; s, sphenoid sinus.
H
CA
S
50
Sphenoid Sinus
https://t.me/med1917
It is not rare to discover extra or incomplete septations.
Minor transversal septations are actually bony partitions between the posterior ethmoid and the sphenoid
sinus and do not represent true sphenoid septations
(Fig. 5.2).
The current classification proposed by Lang in 1988
about the patterns of sphenoid pneumatization distinguishes the sphenoid aeration and the sphenoid wall
contours in relation to the sella turcica.
2
It is often used
in the evaluation of sphenoid approaches. The four categories that this classification comprises are conchal type
(5%), presellar type (5%), sellar type (25%), and postsellar
type (65%) (Fig. 5.3). The sphenoid sinuses may also have
2
1
pneumatized extensions into the clinoid processes or the
pterygoid plates. Aplasia can be seen in 1% and hypoplasia
in approximately 13% of subjects.
3
The sphenoid ostium is often located at the middle
height of the sphenoid sinus. It has an average diameter of
3 mm and is located 7 mm (2–15 mm) above the choana
and 4 mm from the midline, placing it in the upper half of
the anterior wall of the sphenoid sinus.
4
Adjacent to the
superior turbinate, it is 7 cm from the nasolabial angle
of the columella. The posterior sphenoid wall is approximately 9 cm from the base of the columella.
Sphenoid sinus dissection has been linked with unin-
tentional carotid and optic nerve damage (not exceeding
5,6
Damage of the internal carotid arteries or the op-
0.3%).
tic nerves that adhere and lie behind thin bone structures
may happen. In almost 90% of cases, the bone thickness is
less than 0.5 mm
7
or can even be dehiscent (Fig. 5.4a,b).
Postmortem studies have demonstrated that the carotid
artery is found dehiscent in up to 22%.
Planum sphenoidale
C
o
n
c
Pre-
h
sellar
a
l
Sellar
Postsellar
Fig. 5.2 Coronal CT reconstruction of the sphenoid. Note the
major, asymmetric intersphenoidal septum. Arrow 1 points
to an incomplete lower septation of the right sphenoid; arrow
2 indicates a minor septation oriented to the left infraoptic
recess, almost touching the internal carotid artery. Also note
the bilateral presence of Onodi cells. Green arrow points at
the foramen rotundum (V2) and blue circle indicates a small
meningoencephalocele lateral to V2.
Optic nerve
a
Fig. 5.4 Coronal (a) and axial (b) views of ethmoid and sphenoid sinuses. Arrows point the right optic canal dehiscent and left optic
canal. Both optic canals are embedded into the right and left sphenoid sinuses.
Fig. 5.3 Four types of extensions of the pneumatization in
relation with the sella turcica: conchal type, presellar type,
sellar type, or postsellar type.
Right optic nerve Left optic nerve
b
51
Sphenoid Sinus
https://t.me/med1917
The pit of the posterior sphenoid wall caused by the respective protrusions of the optic canal superiorly and the
internal carotid artery laterally and inferiorly is known
as the lateral opticocarotid recess, and it is the projection of the anterior clinoid process of the sphenoid bone
(Fig. 5.5). Other recesses, such as the pterygoid recess,
also vary depending on whether the sphenoid sinus is
well pneumatized or not and constitute anatomic points
of interest in the management of the lateral sphenoid
wall (e.g., approaching encephaloceles comprising Sternberg’s canal, located laterally to V2).
The posterior sphenoethmoidal cell (or so-called Onodi
cell) corresponds to the pneumatization of the most posterior ethmoid air cell that lies laterally and superiorly
to the sphenoid sinus reaching the optic nerve. The incidence of sphenoethmoidal cells demonstrated by computed tomography (CT) scan ranges from 5 to 30% depending
on the study population.
Onodi cells even in 30 to 60% of the subjects. Awareness
of this fact may help reduce the risk of optic nerve trauma
during surgery.
The vidian nerve passes through the pterygoid canal
from the cranium between the pterygopalatine fossa anteriorly (laterally in the fusion line of the pterygoid process with the greater wing of the sphenoid bone) and the
lacerum segment of the internal carotid posteriorly. The
position of the canal may vary from being totally or partially embedded into the sphenoid bone to protruding at
the lateral aspect of the sphenoid sinus (when well pneumatized). The relation between left and right vidian canal
sites is often asymmetric (Fig. 5.6a).
The foramen rotundum is embedded in the sphenoid
bone laterally, containing the maxillary or second branch
of the trigeminal nerve. It also brings sensitive innervation to the sphenoid.
9,10
8
Cadaveric dissections identified
5.2 Preoperative Evaluation
5.2.1 Nasal Endoscopy
Nasal endoscopy is mandatory when there are sinonasal
diseases that require surgery. It can be performed with or
without decongestion, and it leads to visualization of the
middle and superior meati as well as the nasopharynx
and mucociliary drainage pathways.
In operated patients, nasal endoscopy does not necessarily correlate with symptoms.
5.2.2 Computed Tomography
CT scans are helpful to assess the extension of chronic
rhinosinusitis (CRS) and thus help in the classification of
severity of CRS.
marks of all paranasal sinuses and their pneumatization
or changes in previously operated patients.
12
Moreover, CT scans show the bony land-
11
OR
LR
Fig. 5.5 Frontal view of the whole sphenoid sinus in a
fresh specimen. Please note the large pneumatization of the
sphenoid sinus that allows visualization of the opticocarotid
recesses (OR), wide open lateral recesses (LR), and also the
contour of one pterygoid recess (PR). Note both septi end up
on both carotids.
When approaching the posterior ethmoid and the sphe-
noid sinus, the following issues need to be considered:
• Check the degree of sphenoid sinus pneumatization.
• Verify the height of the posterior ethmoid sinus, its re-
tion with the sphenoid sinus, and the degree of su-
la
perior/medial pneumatization of the maxillary sinus.
• Identify the superior meatus and superior turbinate,
which are basic to keep proper orientation within the
posterior ethmoid and to find safely the sphenoidotomy site.
• Review the relationship of the internal carotid arteries
to the sphenoid, intersinus walls, or minimal septations (best identified in the axial view).
• Look for anatomic variations of the sphenoid sinus,
such as the sphenoethmoidal cells, and potential dehiscence of the carotid or optic canal (specially with a
sagittal reconstruction).
The sphenoid ostium is well displayed in paramedian sagittal CT reconstructions but is best seen in the axial plane
(horizontally oriented). Bony structures in the sphenoid
sinus demonstrated on a coronal CT scan indicate extension of the posterior ethmoid sinus above the pneumatized sphenoid sinus.
The length from the sphenoid sinus ostium to each
nostril should be approximately 7 cm when performing
a standard 3-mm sequential coronal CT scans (most standard studies display around 25 scan images).
OR
LR
PR
52
ON
https://t.me/med1917
Sphenoid Sinus
LSS
LCA
b
• Middle and posterior skull base approach.
• Surgery around the internal carotid artery and trigem-
inal g
anglion.
5.4 Surgical Steps
The sphenoidotomy may be performed through a transnasal, a transethmoidal, and a transseptal approach.
5.4.1 Transnasal Sphenoidotomy
This approach is ideal to drain retained secretions through
the sphenoid ostium, and it does not require performing
middle meatal antrostomy or ethmoidectomy.
An advantage of this approach is that it keeps instruments in the midline, avoiding the more risky lateral aspect of the sphenoid sinus.
It is not thought to take biopsies or remove sphenoid
masses. Blind removal of any tissue has to be avoided to
reduce the possibility of unintentional damage to delicate
structures.
• Expose the tail of the superior turbinate to show
the sphenoid ostium with a 0-degree endoscope
(Fig. 5.7a). The middle turbinate can be gently lateral-
ized to gain access.
• Initially, the sphenoid is opened inferiorly and medi-
ally with a mushroom punch. Entering the sphenoid
medially allows enlargement of the natural sphenoid
ostium, thus returning the normal mucociliary flow of
the sphenoid sinus/posterior ethmoid sinus (Fig. 5.7b).
15
RCA
RSS
V2
V
a
Fig. 5.6 (a) Coronal CT scan shows the relationship between optic nerve (ON), V2, vidian (V), and carotid artery (CA).
*Meningoencephalocele. (b) MRI T2 sequence of right sphenoid sinusitis in a patient with pneumococcal meningitis. Intersphenoid
septum pushed to the contralateral side. LCA, left carotid artery; LSS, left sphenoid sinus; RCA, right carotid artery; RSS, right
sphenoid sinus.
Cavum
5.2.3 Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) allows for a better
soft tissue definition (Fig. 5.6b).
It is an ideal supplementary test to CT. Comparison of
staging accuracy of sinonasal disease between CT scan
and MRI demonstrates close correlation between the
two modalities.13 MRI allows differentiating tissue masses from retained secretions. This is particularly helpful
in cases in which the tumor has obstructed the sinus,
leading to a secondary sinusitis, for example, in juvenile
angiofibromas or where the soft tissue is more than an
inflammatory one, such as in a carotid aneurism. Diseases in the sphenoid sinus, from inflammatory disease to
mucoceles, sinonasal, and skull base neoplasms or encephaloceles, need to have an MRI.
14
5.3 Indications
Surgical indications to perform sphenoidotomy/sphenoidectomy mainly include:
• CRS with or without nasal polyposis refractory to med-
ical treatment.
• Sphenoid mucocele.
• (Isolated) fungal sphenoiditis.
• Cerebrospinal fluid (CSF) leaks/meningo(encephalo)
celes of the lateral sphenoid recess.
• Access to the pituitary.
• Malignant sinonasal neoplasm adjacent to the sphe-
noid or involving it.
53
Sphenoid Sinus
https://t.me/med1917
ST
Septum
MT
Right nasal cavity
a
Fig. 5.7 Transnasal sphenoidotomy. (a) Exposure of the right sphenoid ostium with a 0-degree endoscope after out-fracturing the middle
turbinate. (b) Anterior wall of the right sphenoid sinus is exposed and opened medially. MT, middle turbinate; ST, superior turbinate.
Cavum
b
*
a
Fig. 5.8 Transethmoidal right sphenoidotomy. (a) The asterisk, medially, corresponds to the projection of the removed vertical
aspect of basal lamella. The blue line corresponds to the upper limit, the skull base. The yellow line corresponds to the projection of
lamina papyracea. (b) Entering into the sphenoid sinus inferomedially. PE, posterior ethmoid; SS, sphenoid sinus; M, midline. (c) Safe
resection of anterior sphenoid wall using the circular mushroom punch.
The posterior septal artery, a septal branch of the sphenopalatine artery, may become a source of troublesome
bleeding during the sphenoidotomy. It has been suggested to perform the opening approximately 10 mm
above the choana to avoid the artery after detaching
its mucoperiosteum inferiorly. Having a bipolar forceps
at hand in case of inadvertent sphenopalatine bleeding
may be useful.
b
5.4.2 Transethmoidal Sphenoidotomy
This phase starts once the vertical aspect of the (third)
basal lamella of the middle turbinate has been removed
(please check Chapter 3 for more details). Entering
the posterior ethmoid (Fig. 5.8a), an imaginary circle
is drawn taking as landmarks the posterior lamina
papyracea laterally and the skull base superiorly. The
sphenoid sinus has to be opened at the inferomedial
aspect (3–6 hours on the right side and 6–9 hours on
the left side), thus avoiding the lateral and superior
aspects of the sinus, where the optic nerve and carotid artery are located (Fig. 5.8b,c). There is no need to
PE
M
SS
c
exenterate the middle or superior turbinates to open
the sphenoid sinus.
5.4.3 Transseptal Approach to the
Sphenoid Sinus
This approach is the choice when the goal is to remove
extensive sphenoid disease bilaterally or for extended
transsphenoidal procedures, such as pituitary surgery for
macroadenomas, transclival approaches, etc. (Fig. 5.9a,b).
In a well-pneumatized sinus, the pituitary fossa often
displays a convexity at the roof of sphenoid cavity.
Laterally, the bulging of the carotid and optic nerves and
the lateral opticocarotid recess between both serve as
landmarks in transsphenoidal procedures.
Intraoperative complications may include septal
perforations, when the primary intention was to preserve
the vomer. The more bone denuded during surgery, the
more crusting in the postoperation period. In extended,
for example, transclival approaches, the complete floor of
the sinus needs to be drilled to allow an adaptation of the
54
Соседние файлы в папке Библиотека им академика М.И. Перельмана