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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4368_Библиотеки_им_академика_М_И_Перельмана
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Endonasal Endoscopic–Assisted Intraorbital Approach
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the risk of disorientation (Fig. 14.3). Furthermore, the position of the lesion with respect to the vertical line of the
optic nerve (ON) is another critical element to be evaluated.
In all intraorbital procedures, neuronavigation is advisable.
FS
LP
MS
MRM
IRM
EB
IRM
ION
SRM
ON
LRM
MRM
MT
NS
IT
a
NF
LP
EC
To expose the ethmoidal box, which will be finally completely removed, the middle turbinate has to be
resected (Fig. 14.4). Natural ostium of the maxillary sinus
is exposed after a partial uncinectomy.
SOM
LP
MT
IT
b
MRM
SRM
IRM
noMS
OA
ON
LRM
MT
aoMS
IT
c
Fig. 14.3 (a–d) Coronal CT scan evaluation of the sino-orbito-cranial interface. aoMS, accessory ostium of the maxillary sinus; EB,
eyeball; EC, ethmoidal complex; FS, frontal sinus; ION, infraorbital nerve; IRM, inferior rectus muscle; IT, inferior turbinate; LP, lamina
papyracea; LRM, lateral rectus muscle; MRM, medial rectus muscle; MS, maxillary sinus; MT, middle turbinate; NF, nasal fl oor; noMS,
natural ostium of the maxillary sinus; NS, nasal septum; OA, orbital apex; ON, optic nerve; SOM, superior oblique muscle; SRM,
superior rectus muscle.
rMT
UP
noMS
NS
a
EB
C
d
OC
SS
EB
tMT
IT
b
MS
IT
FS
UP
Fig. 14.4 (a, b) Removal of the middle turbinate. C, choana; EB, ethmoidal bulla; FS, frontal sinus; IT, inferior turbinate; noMS,
natural ostium of the maxillary sinus; NS, nasal septum; OC, optic canal; rMT, resected middle turbinate; SS: sphenoid sinus; tMT, tail
of the middle turbinate; UP, uncinate process.
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A standard sphenoethmoidectomy (Fig. 14.5) and a
medial maxillectomy are performed to expose the medial
orbital wall (mainly given by the lamina papyracea). The
choice to spare or not the nasolacrimal duct depends
on the position of the lesion and the use of an anterior
septal window. Usually, ethmoidal foramina can be seen
at the level of the frontoethmoidal suture. The anterior
ethmoidal artery (AEA) passes through the ethmoidal
complex at the level of the roof or even 5 mm below
this level to enter the anterior cranial fossa. The artery
runs in a membrane mesentery (rare) or a thin bony
lamella. The AEA presents nasal branches and an anterior
meningeal branch. The posterior ethmoidal artery
(PEA) usually runs within the skull base/ethmoidal roof.
FS
AEA
LP
PEA
NS
Usually two in numbers, sometimes ethmoidal arteries
can be three or even more (in up to 45%, ethmoidal
arteries may be multiple). In a variable percentage of
cases, PEA is absent, even bilaterally (for more details,
please check Chapter 7).
Once the lamina papyracea is removed, the medial and
inferomedial aspects of the periorbita remain exposed
(Fig. 14.6). Usually, the shape of the medial rectus muscle (MRM) shape is evident in the posterior aspect of the
orbit where there is less extraconal fat.
After removal of the periorbita, the extraconal fat is
exposed (Fig. 14.7). Posteriorly, the extraconal fat is less
evident, so, sometimes, MRM can be found immediately below the periorbit. At the level of the orbital apex,
FS
ON
MS
IOB
LP
NLD
SS
pwMS
SS
a
Fig. 14.5 (a, b) Complete sphenoethmoidectomy and lamina papyracea exposure. AEA, anterior ethmoidal artery; FS, frontal sinus;
IOB, infraorbital bundle; LP, lamina papyracea; MS, maxillary sinus; NLD, nasolacrimal duct; NS, nasal septum; ON, optic nerve; PEA,
posterior ethmoidal artery; pwMS, posterior wall of the maxillary sinus; SS, sphenoid sinus.
AEA
PO
PEA
NS
pwMS
SS
b
AEA
SB
ON
ICA
OF
pwMS
Fig. 14.6 Lamina papyracea removal and periorbita exposure.
AEA, anterior ethmoidal artery; NS, nasal septum; PEA,
posterior ethmoidal artery; PO, periorbita; pwMS, posterior
wall of the maxillary sinus; SS, sphenoid sinus.
146
Fig. 14.7 Extraconal fat exposure. AEA, anterior ethmoidal
artery; ICA, internal carotid artery; OF, orbital fat; ON,
optic nerve; pwMS, posterior wall of the maxillary sinus; SB,
skull base. Black asterisks indicate the anterior edge of the
periorbita.
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the annulus of Zinn is rapidly exposed below the periorbit and not infrequently an extraconal venous channel is evident connecting the orbital system with the
cavernous sinus.
The removal of the extraconal fat exposes the “medial
muscular wall” (Fig. 14.8). It is given mainly by the medial
and inferior rectus muscles and, to a lesser extent, by the
superior oblique muscle. Between the medial and inferior
rectus muscle, it is possible to identify intraconal fat and
the access to intraconal space. The AEA passes between
the MRM and the superior oblique muscle, while the PEA
usually passes above the superior oblique muscle.
Based on the anatomic relationship between the sinonasal complex and the orbit, endoscopic transnasal procedures are thought to offer a good approach to the medial
AEA
MRM
ON
ICA
pwMS
Fig. 14.8 Extraconal fat removal and medial muscular wall
exposure. AEA, anterior ethmoidal artery; ICA, internal carotid
artery; MRM, medial rectus muscle; ON, optic nerve; pwMS,
posterior wall of the maxillary sinus.
and inferomedial orbital spaces (Fig. 14.9). To manage the
medial (mostly inferomedial) intraconal spaces, the best
corridor is located between the medial and inferior rectus
muscles. Sometimes, to increase the size of this window,
the medial aspect of the orbital floor can be removed,
paying attention to the infraorbital nerve. This allows an
increase mobility of the structures (Fig. 14.9).
In the superior aspect, above the MRM, within the
intraconal space the most distal part of the ophthalmic
artery (OA) can be seen, with its terminal branches (usually the AEA and dorsal nasal arteries) (Fig. 14.10). In close
proximity to the OA, the nasociliary nerve (NCN) runs
branching off the anterior ethmoidal nerve and the infratrochlear nerve. The origin of the anterior and posterior
ethmoidal nerves from the NCN can be identified transnasally. At the level of the trochlea, the NCN becomes the
infratrochlear nerve. Close to the NCN and the OA, in the
anterior part of the orbit, the superior ophthalmic vein
(SOV) runs usually lateral to them and on the medial side
of the superior rectus muscle.
Usually, a connecting vein is seen in the anterior part
of the operative window. Within the orbit, a complex
reticular system of fibrous septa divides the fat into
distinct lobules. These septa are well evident in the
anterior orbit and bridges together with the extraocular
muscles, thus “creating” an intraconal and extraconal
space. Posteriorly, this division is less evident. The lateral limit of dissection is given by the ON (Fig. 14.11).
In the upper part, above an axial plane passing through
the ON, the OA, the NCN, and the SOV can be seen. SOV
is usually close to the OA (Fig. 14.11). SOV is the largest
and most important vein of the orbit. In the retrobulbar
fat, the SOV is embedded in and supported by a highly organized connective tissue. It usually originates from the
fusion between the continuation of the supraorbital vein
and the angular vein. On the medial aspect of the MRM,
it is possible to identify the branch of the oculomotor
nerve and the muscular arterial branches usually coming
from the OA. As a general rule, the muscular branches are
nearly all situated in the intraconal side of the muscles,
principally at their posterior part.
a
Fig. 14.9 Transnasal approach to the medial and inferomedial intraconal spaces in a schematic drawing (a) and in a cadaveric
section (b). IRM, inferior rectus muscle; MRM, medial rectus muscle; ON, optic nerve; SOM, superior oblique muscle; SRM, superior
rectus muscle. White asterisk indicates infraorbital nerve; yellow line indicates the medial aspect of the orbital fl oor that can be
removed to increase the size of the surgical window.
SOM
MRM
SRM
IRM
SRM
SOM
ON
MRM
IRM
b
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SB
PEA
a
Fig. 14.10 (a, b) Exposure of superior aspect of medial wall. AEA, anterior ethmoidal artery; AEN, anterior ethmoidal nerve; DNA,
dorsal nasal artery; ITN, infratrochlear nerve; MRM, medial rectus muscle; NCN, nasociliary nerve; OA, ophthalmic artery; PEA,
posterior ethmoidal artery; SB, skull base; SOM, superior oblique muscle. Black circles indicate periorbita.
CV
AEA
MRM
OA
AEN
NCN
SOM
SB
PEA
DNA
b
SOV
EB
ON
IRM
AEA
SOV
OA
AEN
SOM
MRM
MRM
CV
NCN
NCN
OA
AEN
OA
DNA
ITN
a
Fig. 14.11 (a, b) Medial intraconal space dissection. CV, collateral vein; EB, eyeball; IOB, infraorbital bundle; IRM, inferior rectus
muscle; MRM, medial rectus muscle; MS, maxillary sinus; NCN, nasociliary nerve; OA, ophthalmic artery; ON, optic nerve; SOV,
superior ophthalmic vein. White arrow indicates the branch of the oculomotor nerve for the medial rectus muscle.
Once the medial intraconal fat is removed, the
intraorbital portion of the ON, with its tortuous course,
becomes evident (Fig. 14.12). Anteriorly, the ON is closely
associated with a vascular network, mainly given by
the ciliary arteries (branches of the OA). Close to these
vessels, long ciliary nerves are usually well identifiable
(they are branches of the NCNs that arose in the posterior
part of the nerve). In the posterior aspect of the orbit, posterior ciliary arteries (PCAs) can be seen. They
arose independently from the proximal part of the OA:
the superior PCA is always located superior to the ON.
148
IRM
IOB
b
MS
The PCAs run forward and divide into numerous small,
short ciliary arteries that are usually highly convoluted
especially near the globe. The medial PCA and the central retinal artery (CRA) are usually the first branches of
the OA. From an endoscopic transnasal perspective, it is
usually possible to identify the CRA, which usually enters the ON from its inferior surface. Sometimes, it can
also reach the nerve from its medial aspect. It should
be noted that CRA is one of the smallest branches of
the OA and its position is unpredictable preoperatively
(Fig. 14.12).
N
MRM
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ON
CAs
EB
Endonasal Endoscopic–Assisted Intraorbital Approach
EB
ON
LCN
a
Fig. 14.12 (a, b) Optic nerve exposure. CAs, ciliary arteries; CRA, central retinal artery; EB, eyeball; IRM, inferior rectus muscle; LCN,
long ciliary nerve; MRM, medial rectus muscle; ON, optic nerve.
In the orbital apex region, by splitting the annulus of
Zinn between the medial and inferior rectus muscles, the
inferior division of the oculomotor nerve with its braches
becomes evident. Between them, the proximal part of the
orbital OA can be seen (Fig. 14.13).
CRA
IRM
b
ON
14.3 Case Examples
After an episode of an acute rhinosinusitis, a young man
complained about the presence of ocular pain in the
right eye associated with mild ocular movement impairment. MRI evaluation showed the presence of an extra/
intraconal abscess located in close relationship to the
MRM (Fig. 14.14). Given the medial location, the patient
was submitted to a transethmoidal approach to orbital
spaces. No pus was observed in the subperiosteal region,
so the periorbital was opened and a careful dissection
within the fat was performed. The abscess was finally
identified and drained (Fig. 14.14). Culture was positive
for penicillin-resistant Staphylococcus epidermidis. The
postoperative period was uneventful and the patient’s
complains disappeared.
A young woman presented a moderate-sized lesion
located in the right inferomedial extraconal compartment. Given the favorable position, the lesion was
addressed via transnasal route. After a standard sphenoethmoidectomy, lamina papyracea was removed and
periorbital incised. The lesion was easily identified and
removed (Fig. 14.15). The postoperative period was
uneventful. (Case is provided courtesy of Prof. Paolo
Castelnuovo.)
14.4 Complications
14.4.1 Vascular Damages
• Muscular branches, mainly of the MRM: this vessel
can be injured especially in the posterior aspect of the
orbit. This complication is infrequent especially if a
careful perilesional dissection is performed.
ICAc
Fig. 14.13 Orbital apex exposure. CAs, ciliary arteries; CV,
collateral vein; EB, eyeball; ICAc, cavernous portion of the
internal carotid artery; ION, infraorbital nerve; IRM, inferior
rectus muscle; MRM, medial rectus muscle; OA, ophthalmic
artery; ON, optic nerve; pwMS, posterior wall of the maxillary
sinus. Yellow arrows indicate the branches of the inferior
division of the oculomotor nerve.
• CRA: the damage of this artery leads to sudden blindness.
Unfortunately, the position of the CRA is unpredictable.
Most of the time, the artery enters the nerve on its inferior surface, but sometimes it can have a medial entrance.
• Ciliary arteries: this network surrounds the ON and can
be seen from a transnasal view. Their damage can be
very serious and lead to severe visual impairment.
• OA: given the position of the artery, a direct damage
of the vessel is very rare during transnasal intraorbital
procedures.
ON
OA
CRA
CAs
ION
MRM
IRM
pwMS
ON
EB
CV
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LP
LP
ab
PO
d
Fig. 14.14 (a–f) Right extra-intraconal orbital abscess. LP, lamina papyracea; OF, orbital fat; P, pus; PO, periorbita. Red arrow
indicates the abscess.
b
PO
OF
e
c
f
PO
OF
P
LP
PO
a b
H
OF
def
Fig. 14.15 (a–f) Right inferomedial orbital cavernous hemangioma (extraconal). H, hemangioma; LP, lamina papyracea; NS, nasal
septum; OF, orbital fat; PO, periorbita. Red arrow indicates the lesion.
OF
H
NS
c
PO
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14.4.2 Neural Damages
• Motor nerves (branches of the inferior division of ocu-
lomotor nerve): this lesion can lead to a dysfunction of
the muscles (medial and inferior rectus muscles). These
branches usually enter the muscles on their inner surface, in the posterior orbit. Thus, their damage during
transnasal intraorbital procedures is not common.
Notwithstanding, a careful and smooth dissection is
strongly advisable because it greatly reduces the risk of
damage to these branches.
• Long ciliary nerves: these nerves are mainly sensory
but can also contain sympathetic fibers for muscles
(medial and inferior rectus muscles). These branches
usually enter the muscles on their inner surface, in the
posterior orbit. Thus, their damage during transnasal
intraorbital procedures is not common. Notwithstanding, a careful and smooth dissection is strongly advisable because it greatly reduces the risk of damage to
these branches.
• ON: a direct damage to the ON branches is infrequent if
a careful dissection is performed.
• Long ciliary nerves: these nerves are mainly pupillary
dilatation. They can be found on the medial aspect of
the ON and their damage can lead to some disturbances
in sclera’s sensation.
14.4.3 Muscular Damage
• Mainly to MRM: direct trauma or even surgical maneu-
vers by themselves can lead to a post-op impairment
with consequent diplopia. Usually, the dysfunction
disappears within months.
• To avoid an increase of intraorbital pressure, a careful
• Transient diplopia (especially if related to MRM impair-
tasis should be achieved at the end of the proce-
hemos
dure. Notwithstanding, given the periorbital window, a
severe intraorbital hematoma rarely develops after this
type of procedure.
ment) should not be considered as a complication itself
but rather a possible temporary consequence.
14.5 Tips and Tricks
Creation of an anterior septal window allows a two-nostril technique with a 3- to 4-hand technique and a more
favorable “angle of attack” (Fig. 14.16). This reduces the
potential conflict between instruments.
To increase the working window between the medial
and inferior rectus muscles, the MRM can be medialized
and “attached” temporarily to the nasal septum
(Fig. 14.17). Usually, this is done using a vessel loop or
a stitch. This maneuver improves the ability to dissect
and work within medial intraconal space, reducing at the
same time the conflicts between instruments. At the end
of the surgery, the MRM is repositioned.
Anterior stiffening of the medial and inferior rectus
muscles by means of a transconjunctival looping represents another great help for transnasal orbital dissection, especially for extraconal lesions (Fig. 14.18). By
pulling anteriorly the stitches, the muscles become rigid,
thus making dissection easier and safer.
The dissection should be performed with smooth (and
more rarely sharp) instruments. A careful and wise use of
bipolar coagulation on the surface of the lesion is very useful to shrink the lesion and thus to facilitate its removal.
NS
IT
b
b
PO
NS
pwMS
a
Fig. 14.16 Anterior septal window. (a) Schematic view of the septal window. (b, c) Endoscopic view (right nasal cavity) of the septal
window. (d) Contralateral view of the left nasal fossa and surgical fi eld (inferomedial aspect of the orbit). (e) Working possibilities
(endoscope in the left nasal fossa and instruments coming from the right nostril). IT, inferior turbinate; NS, nasal septum; OF, orbital
fat; PO, periorbita; pwMS, posterior wall of the maxillary sinus. Light blue circles indicate the orbital window.
d
c
c
NS
e
NS
OF
IT
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MRM
EB
NS
a
b
MRM
MRM
MRM
c
Fig. 14.17 (a–d) Medial attachment of medial rectus muscle. EB, eyeball; MRM, medial rectus muscle; NS, nasal septum.
MRM
a b
Fig. 14.18 (a–c) Extraocular muscles anterior stiff ening. IRM, inferior rectus muscle; MRM, medial rectus muscle. Black arrows
indicate inferior rectus muscle insertion; blue arrows indicate medial rectus muscle insertion.
d
IRM
c
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14.6 Dedicated
Instrumentations
The transnasal approaches to the orbital spaces require
adequate instrumentation for a correct procedure. The
surgical set should include several dissectors of different
sizes, plus delicate scissors of different angles (like those for
cranial base surgery). Delicate bipolar forceps with straight
and angled tips can be very useful. Navigation is advisable.
Suggested Readings
Castelnuovo P, Dallan I, Locatelli D, et al. Endoscopic transnasal intraor-
bital surgery: our experience with 16 cases. Eur Arch Otorhinolaryngol
2012;269(8):1929–1935
Dallan I, Castelnuovo P, de Notaris M, et al. Endoscopic endonasal
anatomy of superior orbital fissure and orbital apex regions: critical
considerations for clinical applications. Eur Arch Otorhinolaryngol
2013;270(5):1643–1649
Dallan I, Seccia V, Lenzi R, et al. Transnasal approach to the medial in-
traconal space: anatomic study and clinical considerations. Minim Invasive Neurosurg 2010;53(4):164–168
McKinney KA, Snyderman CH, Carrau RL, et al. Seeing the light:
endoscopic endonasal intraconal orbital tumor surgery. Otolaryngol
Head Neck Surg 2010;143(5):699–701
Rootman J. Orbital Surgery. A Conceptual Approach. 2nd ed. Philadelphia,
PA: Wolter Kluwer, Lippincott Williams & Wilkins; 2014
Tomazic PV, Stammberger H, Habermann W, et al. Intraoperative medial-
ization of medial rectus muscle as a new endoscopic technique for approaching intraconal lesions. Am J Rhinol Allergy 2011;25(5):363–367
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