10.14639/0392-100X-suppl.1-41-2021-06
The transorbital approaches are a group of surgical procedures performed passing through the orbital spaces and aimed to reach deeper areas. This kind of surgery has been proved to be safe and effective in the management of selected lesions of the anterior, middle and infratemporal fossa. The aim of the present study is to perform a review of the literature, in order to draw the reader’s attention on the main features of this kind of surgery, focusing on the anatomical background and the surgical setting; we will also summary the current indications and contraindications to this approach and find out the related complications and the possible alternatives. Even if we consider the transorbital approach as a promising route to the skull base, we underline that there is no better approach over another and the choice must always consider several elements. Furthermore, as for every skull base procedure, a multidisciplinary management is strongly advisable.
application/xml
1827-675X
1687
en
Stefano Berrettini
https://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
endoscopy
When multidisciplinary surgical trans-orbital approaches should be considered to reach the skull base
Text.Serial.Journal
https://www.actaitalica.it/
41
Annual congress report
2021-05-14
2021-05-10
2021-05-14
2021-05-14
59-66
1
Stefano Berrettini
2021/05/14
10.14639/0392-100X-suppl.1-41-2021-06
59
Otolaryngology Unit, Department of Surgical, Medical, Molecular Pathology and Emergency Medicine, University Hospital of Pisa, Italy;
1827-675X
endoscopy
66
When multidisciplinary surgical trans-orbital approaches should be considered to reach the skull base
https://www.actaitalica.it/article/download/1687/560
41
ACTA OTORHINOLARYNGOLOGICA ITALICA 2021;41(SUPPL.1):S59-S66; doi: 10.14639/0392-100X-suppl.1-41-2021-06




When multidisciplinary surgical trans-orbital
approaches should be considered to reach the skull
base
Ruolo degli approcci chirurgici multidisciplinari trans-orbitari nella gestione
della patologia del basicranio
Iacopo Dallan1, Lodovica Cristofani-Mencacci1, Giacomo Fiacchini1, Michele Caniglia2, Stefano Sellari-Franceschini1,
Stefano Berrettini1
1
  Otolaryngology Unit, Department of Surgical, Medical, Molecular Pathology and Emergency Medicine, University Hospital of Pisa,
Italy; 2 Department of Neurosurgery, University Hospital of Pisa, Italy


SUMMARY
The transorbital approaches are a group of surgical procedures performed passing through
the orbital spaces and aimed to reach deeper areas. This kind of surgery has been proved
to be safe and effective in the management of selected lesions of the anterior, middle and
infratemporal fossa. The aim of the present study is to perform a review of the literature, in
order to draw the reader’s attention on the main features of this kind of surgery, focusing on
the anatomical background and the surgical setting; we will also summary the current in-
dications and contraindications to this approach and find out the related complications and      Received: October 24, 2020
the possible alternatives. Even if we consider the transorbital approach as a promising route    Accepted: January 16, 2021
to the skull base, we underline that there is no better approach over another and the choice
must always consider several elements. Furthermore, as for every skull base procedure, a         Correspondence
multidisciplinary management is strongly advisable.                                              Lodovica Cristofani-Mencacci
                                                                                                 Otolaryngology Unit, Azienda Ospedaliero-Univer-
KEY WORDS: skull base, surgical procedures, orbit, endoscopy                                     sitaria Pisana,
                                                                                                 via Paradisa 2, 56124 Pisa, Italy
                                                                                                 Tel. +39 050 997502
RIASSUNTO                                                                                        E-mail: lodovicacristofani@yahoo.it
Sotto il termine “chirurgia trans-orbitaria” viene attualmente indicato un gruppo di pro-
cedure chirurgiche volte a raggiungere la base cranica, sfruttando la finestra orbitaria.        Funding
Questo tipo di chirurgia si è dimostrata sicura ed efficace per la gestione di patologie         None.
selezionate della fossa cranica anteriore, della media e della fossa infratemporale. L’obiet-
tivo di questo lavoro è quello di effettuare una revisione della letteratura, con lo scopo di    Conflict of interest
veicolare l’attenzione del lettore su quelle che sono le principali caratteristiche di questo    The Authors declare no conflict of interest.
tipo di chirurgia, concentrandosi in particolare sul necessario background anatomico e
sul setting operatorio richiesto; riassumeremo le attuali indicazioni e controindicazioni ed
                                                                                                   How to cite this article: Dallan I, Cristofani-
evidenzieremo le possibili complicanze associate a tale chirurgia e le eventuali alternative       Mencacci L, Fiacchini G, et al. When multidisci-
da intraprendere. Pur reputando che questa chirurgia sia molto promettente nella gestione          plinary surgical trans-orbital approaches should
di alcune patologie del basicranio, vogliamo tuttavia sottolineare come non esista mai un          be considered to reach the skull base. Acta Otorhi-
approccio chirurgico migliore di un altro in termini assoluti, e che la scelta finale debba        nolaryngol Ital 2021;41(SUPPL.1):S59-S66.
essere sempre il frutto di considerazioni che valutano molteplici elementi. In ultimo, si vuo-     https://doi.org/10.14639/0392-100X-sup-
le sottolineare che, come in altre procedure sul basicranio, i migliori risultati si ottengono     pl.1-41-2021-06
con una gestione multidisciplinare.
                                                                                                 © Società Italiana di Otorinolaringoiatria
PAROLE CHIAVE: base cranica, procedure chirurgiche, orbita, endoscopia                           e Chirurgia Cervico-Facciale


                                                                                                                OPEN ACCESS

                                                                                                 This is an open access article distributed in accordance with
Introduction                                                                                     the CC-BY-NC-ND (Creative Commons Attribution-Non-
                                                                                                 Commercial-NoDerivatives 4.0 International) license. The
Generally speaking, with the term “transorbital approaches” we consider a                        article can be used by giving appropriate credit and mentio-
                                                                                                 ning the license, but only for non-commercial purposes and
group of surgical procedures performed passing through the orbital spaces                        only in the original version. For further information: https://
aimed to reach deeper areas. As a matter of fact, transorbital endoscopic-                       creativecommons.org/licenses/by-nc-nd/4.0/deed.en




                                                                                                                                                         S59
I. Dallan et al.




assisted surgery is one of the most recent, fascinating and       Anatomical background and surgical
promising areas in skull base surgery. Its development            considerations
should be considered as a natural step of the progression
of the minimally invasive surgical approaches to the skull        The superior eyelid, viewed from an anterior to posterior
base. Transnasal endoscopic-assisted approaches, although         direction, is formed by two lamellae: an anterior lamella,
incredibly evolved, have their own limits. Probably the two       consisting of skin and the orbicularis oculi muscle, a pos-
most important are: 1) the frequent need of angled endo-          terior lamella, consisting of Muller’s palpebral muscle and
scope and cross-planar technique and instruments to visu-         levator aponeurosis. The orbital septum, in the upper part
alize and manage the surgical target; 2) the nasal corridor       of the eyelid, is located between these two lamellae. The
to the skull base becomes progressively constricted as the        orbital septum is in continuity with the periorbita and the
target is reached, especially in its lateral aspect. Further-     periosteum of the external cranial surface and it is a mem-
more, transnasal endoscopic approaches necessitate place-         branous sheet. The superior septum originates from the
ment of the endoscope and instruments in a similar vec-           orbital rim at the arcus marginalis. Supero-medially, it is
tor with minimal offset angle 1. Based on these grounds,          pierced by vessels and nerves. It is located medially behind
it came naturally to think of the orbit not only as a possi-      the medial palpebral ligament and laterally it is located an-
ble site of pathology but also as a corridor to deeper areas.     teriorly to the lateral palpebral ligament. It attaches itself to
Thanks to the innovative work of Kris Moe, this idea turned       Muller’s muscle and the superior tarsus inferiorly, ending
into reality 2. This kind of surgery, named TONES (Trans-         in the pre-tarsal skin. The upper eyelid is supported by the
Orbital Neuro-Endoscopic Surgery) has been proved to be           upper tarsal plate, which forms with its lateral and medial
safe, and from the very initial experience several groups         canthal tendons the tarso-ligamentous sling. The levator
around the world have started to add their own data to this       palpebrae and its aponeurosis form the superior eyelid re-
topic. Among the main advantages of TONES we include a            tractor system, which passes inferiorly from the Whitnall’s
shorter period of hospitalization, rapid recovery, very good      ligament to reach the tarsal plate and the pretarsal palpe-
cosmetic outcomes and reduced, if not absent, morbidity           bral skin. Anatomically speaking Whitnall’s ligament is a
related to brain retraction 2. More interestingly, this kind of   condensation of fascial covers around the levator palpebrae
approach has been successfully combined with other surgi-         superioris muscle. As for the aponeurosis of the levator,
cal procedures in order to offer multiple entry windows,          its lateral horn is inserted on the Whitnall tubercle, while
overcoming the own limits of each of them, giving rise            the medial horn is inserted on the posterior lacrimal crest.
to a “multiportal” procedure. The golden rule of “not be-         Muller’s sympathetic muscle should be considered as an
ing dogmatic” is leading worldwide surgeons to introduce          accessory tendon of the levator palpebrae, in the context
variations to the actually known solutions, always with the       of the upper eyelid. Along the anterior surface of the upper
intent to improve results and minimize complications and          tarsus runs the marginal arterial arcade, mainly from the
sequelae. The aim of this manuscript is to perform a re-          medial palpebral and lacrimal arteries. This means that the
view of the literature, in order to investigate how this new      blood supply for the superior eyelid comes mainly from the
transorbital approach could improve the skull base surgery.       ophthalmic artery. Lesser contribution comes from the in-
We will, therefore, highlight the characteristics that may        fraorbital, temporal, transverse facial and angular arteries.
be useful to clinician in the choice of the best approach for     At the level of the superolateral aspect of the orbital rim,
the patient, in a personalized view of the surgical practice.     the upper lobe of the lacrimal gland can be appreciated just
In this respect, although several incisions and approaches        behind the orbital septum. It lies above the lateral extension
have been described and proposed 1,3, in this chapter we          of the levator palpebrae fascial system. The lacrimal gland
will focus mainly on the superior eyelid endoscopic-assist-       is divided into two portions: an orbital (or upper) portion
ed approach exploring the following items:                        that is lodged in the lacrimal fossa (frontal bone) and a pal-
• anatomical background and surgical considerations;              pebral portion that extends through the lateral horn of the
• surgical instrumentation and setting (multidisciplinary         levator aponeurosis into the supero-lateral fornix (it can be
   management);                                                   seen shining through the conjunctival layer). The upper and
• current indications and contraindications;                      lower lateral tarsal tendons form the lateral canthal tendon.
• possible alternatives;                                          It inserts into the periorbita overlying the Whitnall’s lateral
• complications;                                                  tubercle. In the medial canthal tendon we can identify two
• case examples.                                                  heads, superficial and deep. The superficial head attaches
Other transorbital approaches will not be discussed in this       anteriorly to the lacrimal fossa and the frontal process of
paper and we advice to refer to dedicated literature.             the maxillary bone and it’s thicker. The deep head attaches



S60
                                                                                                                 The trans-orbital route to the skull base




to the posterior lacrimal crest and it’s thinner. The posterior                    greater wing of the sphenoid has to be completely removed
limb of the medial canthal tendon gives the medial compo-                          to reach the dura mater of the anterior part of the temporal
nent of the orbital septum.                                                        lobe. According to the target of surgery, the approach can
From an anatomo-surgical point of view, once the orbital                           be partially extended to the lesser wing of the sphenoid and
rim is reached and skeletonized as needed, we then proceed                         toward the anterior clinoid process. If necessary, the frontal
with a careful sub-periosteal dissection until the lateral                         bone can be partially resected, and if an intradural work has
aspects of the superior (SOF) and inferior orbital fissures                        been planned, the spheno-parietal sinus is advisable to be
(IOF) are identified and adequately exposed. We strongly                           identified and managed. In case of intracranial approaches,
advice to perform a careful dissection, sparing the integrity                      the dura is opened and the anterior part of the temporal
of the periorbita (in order to avoid fat prolapse into the sur-                    lobe of the brain is reached, as well as the lateral wall of
gical field). During this dissection several bridging vessels                      the cavernous sinus. In more extended approach, once the
can be identified; they must be coagulated and cut to avoid                        lesser wing of the sphenoid and partially the frontal bone
annoying bleeding during the procedure. In 50-60% of sub-                          have been removed, the most medial part of the sylvian fis-
jects the cranio-orbital foramen (Hyrthl’s foramen) can be                         sure and its content can be visualized.
found; it is close to the superior orbital fissure and transmits                   If the meningo-orbital band is split, an interdural way to
usually the recurrent meningeal artery (also named menin-                          the lateral wall of the cavernous sinus and Meckel’s cave is
golacrimal branch). As anatomical variation, this vessel can                       reached. This is not a proper intradural approach because it
pass through the SOF. In transorbital “corridor” surgery,                          spares the integrity of the dura propria and avoids to expose
like the one discussed in this paper, when the periorbita is                       the brain parenchima; anyway it allows a direct and efficent
exposed it should be spared in order to create the “pocket                         way to reach the Meckel’s cave and the anterior petrosal area.
room” for the instrumentations. As possible targets, in such                       If the lesion is located below the middle cranial fossa or
an approach, we can identify the anterior and middle crani-                        in the upper infratemporal fossa area, an inferior extension
al fossa and even the infratemporal fossa (Fig. 1). Regard-                        of the “middle cranial fossa approach” can be performed
less the target, the first surgical step is to expose completely                   removing the floor of the MCF thus exposing the upper as-
the inner surface of the temporalis muscle. By doing this,                         pect of the infra-temporal fossa content.
the room for work is enlarged and an increased surgical                            In an “anterior cranial fossa approach”, the orbital part of
freedom for the intruments is gained. When dealing with                            the frontal bone is removed, along with a part of the lesser
a “middle cranial fossa approach” the orbital part of the                          sphenoid wing, to perform a craniectomy. The greater wing
                                                                                   of the sphenoid is normally only partially resected. Then
                                                                                   the dura is exposed and opened if the procedure requires it.
                                                                                   Intracranial work follows as necessary.

                                                                                   Surgical instrumentations and setting
                                                                                   Patient position is the same as for any standard endoscop-
                                                                                   ic-assisted skull-base procedure. For extradural approaches
                                                                                   we generally do not fix the head of the patient, while the
                                                                                   head is normally fixed if intracranial dissection is antici-
                                                                                   pated. Anyway, the head position may be changed during
                                                                                   surgery, thus allowing different angles of attack to the sur-
                                                                                   gical target. It is strongly advisable that the operating room
                                                                                   be set to allow a double screen vision and neuronavigation.
                                                                                   We would like to emphatize the concept that this kind of
                                                                                   surgery can be performed endoscopically and/or micro-
                                                                                   scopically, or better yet in a combined blended solution.
Figure 1. Multipanel figure showing the transorbital endoscopic-assisted           In our experience, we never fix the endoscope in a holder,
approach to the skull base. The orange circle shows the position of the anterior   but it could be probably useful in some instances, as demon-
cranial fossa (ACF); the orange narrow its content, the frontal lobe. The yellow   strated by other groups. These procedures are usually per-
circle shows the position of the middle cranial fossa (MCF); the yellow narrow
                                                                                   formed via a 3-4 hands technique (Fig. 2). In transpalpebral
the temporal lobe, which is behind the dura of the MCF. The light blue circle
shows the position of the infratemporal fossa (ITF); the light blue narrows the    procedures, the role of a third surgeon helping in creating
content of the upper part of the ITF.                                              adequate space for working is of paramount importance. In



                                                                                                                                                    S61
I. Dallan et al.




 A                                           B                                  The choice of a transorbital endoscopic approach over
                                                                                transnasal or open transcranial pathways implies different
                                                                                considerations:
                                                                                • the surgical team’s preference and expertise;
                                                                                • a good interdisciplinary cooperation among otolaryn-
                                                                                   gologist, orbital surgeon and neurosurgeon;
                                                                                • the biological behaviour of the lesion and the possibility
                                                                                   to gain direct access to it with adequate surgical free-
                                                                                   dom;
C                                            D
                                                                                • the chance to completely control the surgical field and
                                                                                   any possible intraoperative complications 5.
                                                                                Among the current indications of a superior eyelid ap-
                                                                                proach we can describe selected:
                                                                                • spheno-orbital meningiomas;
                                                                                • Meckel’s cave schwannoma;
                                                                                • laterally-located anterior cranial fossa meningioma;
                                                                                • lesions within the lateral recess of the frontal sinus;
                                                                                • laterally-located epidural abscesses;
                                                                                • vascular and lymphatic malformations;
Figure 2. External intraoperative views of the surgical area in endoscopic-
assisted superior eyelid approaches. In A and B the surgical team is composed   • skull base defects (mainly located in the lateral recess of
of 3 surgeons: the second surgeon holds the endoscope, the first surgeon is        the sphenoid sinus);
free to use both hands; the third surgeon create a wide surgical window. In D   • other lesions of the Meckel’s cave of the anterior petrous
a combined endoscopic and microscopic-assisted procedure.
                                                                                   apex region;
                                                                                • huge mucoceles of the orbit and cranial cavity (in com-
                                                                                   bination with transnasal approach).
combined multiportal approaches, a good versatility of the
surgical team is required. In this respect we would like to                     The transorbital endoscopic surgery, by means the superior,
strongly underline the extreme importance of a multidisci-                      lateral and supero-lateral approaches (mainly performed
plinary evaluation and management. The close collabora-                         via a superior eyelid approach), may be used in case of dis-
tion with the neurosurgeon, opthalmoplastic surgeon, but                        eases involving the anterior cranial fossa, providing good
also maxillofacial and interventional radiologist and radio-                    access and visualization. Furthermore, the opening of the
therapist is the key for the success. In other words we want                    orbital roof in the floor of the frontal sinus allows reaching
to stress the concept that this kind of surgery should not                      lateral lesions of the frontal sinus, difficult to access with
be considered a “one-man show” but rather the field where                       transnasal surgery such as inverted papilloma and mucoce-
different competences share their own experience and skill                      les 6. At the same time, this kind of surgery allows work-
in a dynamic and harmonic fashion.                                              ing angles more favorable to expose the anterior skull base,
Regarding instrumentations, we can advice the use of typi-                      preserving the paranasal system and physiology when pos-
cal neuroendoscopic instrumentation. A high-speed drill or                      sible. Literature on the topic mainly describes case reports
eventually piezo-electric tool can be used for bony work.                       and small case series, and one of the largest experiences
Also ultrasonic bone aspirators have been used for this pur-                    of pure TONES is described by Ramakrishna and Moe
pose and showed their potential in selected cases.                              in 2016, with 45 TONES procedures directed to the skull
                                                                                base 4.
                                                                                Among clinical indications to perform transorbital surgery
Current indications and contraindications                                       for ACF, Authors report CSF leaks; repairs of cranial base
Endoscopic transorbital approaches, although at their dawn,                     fractures; selected tumours and optic nerve decompres-
showed to be feasible and safe as a minimally invasive and                      sions; meningoencephaloceles; inflammatory conditions
minimally disruptive surgery 4, able to provide direct ac-                      and sinogenic infectious complications involving the ante-
cess to deeper lateral areas of the facial skeleton and skull                   rior cranial fossa 2,4,7. In all such cases the transorbital en-
base. Transorbital procedures may be performed in case of                       doscopic surgery represented a viable technique for lesions
disease involving the orbit itself or structures adjacent to                    difficult-to-reach with other pathways or an additional tool
the orbit, such as the paranasal sinuses, the infratemporal                     to gain the greater access to such challenging diseases 8.
fossa, and the anterior and middle cranial base.                                One of the current main fields of interest using TONES is



S62
                                                                                                  The trans-orbital route to the skull base




related to the management of disease within the middle cra-        that most of these cases, anyway, needs to be managed via
nial fossa. Skull base lesions of this area are traditionally      a combined multiportal procedure.
challenging to be approached, because of the anatomical            Thus said, assuming that a single surgical approach might
complexity of this region and the presence of noble neu-           not be able to complete manage deep, multicompartimental
rovascular structures, such as the Internal Carotid Artery         and difficult-to-access skull base lesions, a multiportal ap-
(ICA), several cranial nerves, and venous plexus 9,10. All         proach, providing simultaneous entry windows, should be
classic transcranial approaches used to manage lesions of          seriously considered 21. In such cases, the superior eyelid
the MCF have their main limits in requiring an extensive           approach may be associated with other transorbital, trans-
bone removal, the disruption and possible post-operative           nasal or even transcranial accesses, ensuring a better visu-
atrophy of the temporalis muscle and a moderate-to-severe          alization and manipulation of the lesion from synchronous
brain retraction 10. In this scenario, a purely endoscopic ap-     different perspectives, as well as a reduced risk of collateral
proach such as the transorbital superior-eyelid route, may         damage 18. If a single approach, in fact, may be insufficient
allow to expose the lateral middle cranial fossa by extra-         to address lesions that cross neurovascular structures or are
dural removal of the greater and lesser sphenoid wings, fol-       deeply located, the use of multiple accesses may allow an
lowed by the dissection of the so called meningo-orbital           augmented visualization, avoiding potentially devastating
band, with minimal disruption of normal tissue 11,12. In           complications 21.
endoscopic-assisted surgery to Meckel’s cave and petrous           Technically speaking, the multiportal approach has its
apex, among the advantages of the transorbital approach            strength in the capability to perform a 360° approach, for
over the endonasal patways, Lee reports the shorter access         instance to the optic canal and the cavernous sinus, as well
route and the possibility to perform an “interdural” dissec-       as the infratemporal fossa and selected complex cases in-
tion within the lateral wall of the cavernous sinus with a         volving the anterior and middle cranial fossa 22. And more
easier manipulation of tumors at their lateral and posterior       than in a single window approach, the multiportal surgery
borders, sparing the vidian nerve 13. Literature on the topic      provides a multihands technique, similarly to the open ap-
is in steady growth with several anatomical comparative            proaches, taking advantages of the role of the second and
studies performed to value the feasibility of the transorbital     third surgeons to gain an adequate exposure and visualiza-
approaches over endonasal and open patways 14,15. Among            tion 18.
published clinical series, the superior eyelid approaches to       Among surgical target, Meckel’s cave and cavernous si-
the middle skull base have been successfully used to man-          nus pathologies seem to benefit from this kind of solu-
age spheno-orbital meningiomas (even if the en-plaque              tion, as an alternative technique that may reduce the high
types remain a challenge) 16 and neoplastic diseases such as       morbidity traditionally associated with the other surgical
trigeminal schwannomas 17 and metastatic lesions 10. Any-          accesses.
way, different Authors remark the limits of such approach,         Different Authors report case report and series with the mult-
underlying the possibility that the unfamiliarity with the         iportal approach, represented by a combination of transorbi-
orbital anatomy may lead to orbital and globe injuries 13,18.      tal and transnasal routes applied in clinical settings 21-24. In
So, it must be stressed that a dogmatic approach to such           all cases this combination appeared safe, effective and able
complex lesions is not appropriate and the surgical exper-         to take advantages of each single approach.
tise and confidence with the transorbital route should be          As a general rule regarding possible contraindications,
properly considered before choosing the surgical access.           we do feel that, whenever major vessels are totally en-
Last but not least, the age of the patient, the possible co-       cased by the lesion (regardless the lesion), traditional
morbidities and the biological behaviour of the lesion must        transcranial routes should be considered as first option. In
be carefully evaluated 5,13,18.                                    such cases performing different “alternative” approach-
The infratemporal fossa is another possible target area            es, like multiportal endoscopic-assisted ones, should be
reachable through a superior eyelid approach, since it lies        well evaluated and balanced. Obviously, a case-by-case
inferiorly to the middle cranial fossa floor. Its management       evaluation is mandatory by an experienced and wise mul-
may require the use of complex approaches, even if deci-           tidisciplinary team.
sive steps forward have been made with the advent of the
endonasal endoscopic tecniques 19. In this respect, the orbit
may represent a new potential option to reach the upper as-
                                                                   Possible alternatives
pects of the infratemporal fossa, through both a superior or,      In Table I, we schematically report the main advantages
probably better, an inferior orbital access (using the inferior    and limitations of the transorbital endoscopic approach
orbital fissure as a natural corridor) 20. It must be underlined   compared to the classical open surgical approaches.



                                                                                                                                     S63
I. Dallan et al.




Table I. Advantages and limitations of the superior eyelid endoscopic-assisted approach compared to the more traditional open ones.
                                                                  Advantages                                              Limitations
 Superior eyelid endoscopic-assisted                         Short distance to the target                        Difficult control of the lateral aspect of the temporal
 approach                                                No nerve or major vessels crossing                                                fossa
                                                 Good control of the anterior pole of the temporal lobe           Major vessels encasement or highly vascularized
                                                    and of the medial aspect of the Sylvian fissure                                       lesions
                                                Good access to lateral wall of the CS and Meckel’s cave              Lesions extending too posteriorly or inferiorly
                                                                  (and petrous apex)
                                                             No need for brain retraction
 Supraorbital approach                                               Small incision                                                No control of ITF
                                                  Good control of anterior and suprasellar/parasellar            No control of anterior temporal lobe region and of
                                                               regions (superior aspect)                       infero-lateral aspect of CS (inferior parasellar region)
 Fronto-temporal approach                         Good exposure of anterior and middle cranial base                   Need for bony work with large skin flap
                                                                                                                              Very difficult control of ITF
                                                                                                               Necessity for management of the anterior part of the
                                                                                                                     temporal lobe to get the lateral wall of CS
 Pterional approach                                Good exposure of anterior and middle cranial base                   Need for bony work and large skin flap
                                                           Good exposure of sylvian fissure                                Difficult control of PPS and ITF
                                                                                                                  Need for the management of anterior part of the
                                                                                                                     temporal lobe to get the lateral wall of CS
 Subtemporal approach                            Good exposure of lateral aspect of parasellar, anterior              Need for bony work with large skin flap
                                                 pole of the temporal lobe and anterolateral posterior                  Very difficult control of PPS and ITF
                                                                     cranial fossa                                       No control of anterior cranial base
                                                                                                                Need for management of anterior pole of temporal
                                                                                                                lobe to obtain space for access to lateral aspect of
                                                                                                                                   parasellar region
                                                                                                               Need for major retraction to obtain suprasellar access
 FTOZ (& variations) approach                      Wide exposure of anterior and middle cranial base                       Difficult control of PPS and ITF
                                                   Good exposure of supralateral aspect of the orbit             Need for extensive bony work and large skin flap
                                                  Access extending to interpeduncolar and prepontine
                                                                        cisterns
CS: Cavernous Sinus; ITF: Infratemporal Fossa; PPS: Parapharyngeal Space; FTOZ: Fronto-Temporal Orbito-Zygomatich approach.



Complications                                                                           vented with adequate tricks. Post-operative bleeding and
                                                                                        an eventually associated compartimental syndrome (with
Surgical complications can be mainly divided in two
                                                                                        sight-threathning condition) are rare but possible in tran-
groups: complications related to the surgical approach
                                                                                        sorbital “corridor” surgery, requiring promt management
and complications related to the target regions. Obvi-
                                                                                        and decompression. All these aspects should be discussed
ously, the latter are independent to the chosen approach
                                                                                        extensively with the patients, and all the possible alterna-
and may occur during any approaches. Another issue is
                                                                                        tives taken into considerations.
the case of complications related to the approach itself.
More in details, the palpebral phase can be associated to
the damage to the levator palpebrae muscle, thus leading                                Clinical examples
to post-operative ptosis. To avoid such complication, the                               In Figure 4 we show a right spheno-orbital meningioma
use of loupes or any other magnification system can be of                               treated with a multiportal transnasal-transorbital endoscop-
great help. Post-operative lid swelling may be significant.                             ic-assisted approach.
Chemosis can be present and significant. Severe injuries
of the extraocular muscles, mainly the lateral rectus mus-
cle, although really rare can be associated with post-op-
                                                                                        Conclusions
erative diplopia. This occurs especially during drilling of                             In conclusion, the superior eyelid endoscopic-assisted ap-
the bone. A piece of silastic sheet could be useful in order                            proach may be considered as a safe and promising approach
to protect orbital tissues. In case of extended superior ap-                            to selected disease of the infratemporal, anterior and mid-
proach, a possible damage to supraorbital and suprath-                                  dle cranial fossa. And the multiportal approach, moreover,
roclear bundles can lead to forehead numbness. Corneal                                  may overcome the limits of a single procedure, offering a
abrasion and damage is a possible risk and can be pre-                                  multiperspective view of the spaces and the possibility to



S64
                                                                                                                      The trans-orbital route to the skull base




A                       B                         C                             References
                                                                                1
                                                                                     Miller C, Bly R, Moe KS. Endoscopic orbital and periorbital ap-
                                                                                     proaches in minimally disruptive skull base surgery. J Neurol Surg B
                                                                                     Skull Base 2020;8:459-471. https://doi.org/10.1055/s-0040-1713900
                                                                                2
                                                                                     Moe KS, Bergeron CM, Ellenbogen RG. Transorbital neuroendoscop-
                                                                                     ic surgery. Neurosurgery 2010;67:ons16-28. https://doi.org/10.1227
                                                                                     /01.NEU.0000373431.08464.43
D                        E                        F                             3
                                                                                     Stefko ST. Combined Surgical approaches in and around the or-
                                                                                     bit. J Neurol Surg B Skull Base 2020;8:472-479. https://doi.
                                                                                     org/10.1055/s-0040-1713938
                                                                                4
                                                                                     Ramakrishna R, Kim LJ, Bly RA, et al. Transorbital neuroendo-
                                                                                     scopic surgery for the treatment of skull base lesions. J Clin Neurosci
                                                                                     2016;24:99-104. https://doi.org/10.1016/j.jocn.2015.07.021
                                                                                5
                                                                                     Gassner HG, Schwan F, Schebesch KM. Minimally invasive sur-
                                                                                     gery of the anterior skull base: transorbital approaches. GMS Curr
Figure 3. MRI-based evaluation of a right orbital and epidural abscess. In A,        Top Otorhinolaryngol Head Neck Surg 2016;14:Doc03. https://doi.
                                                                                     org/10.3205/cto000118
B and C the pre-operative findings. In D, E and F the post-operative imaging
after a superior eyelid approach to orbit and anterior cranial base.            6
                                                                                     Kopelovich JC, Baker MS, Potash A, et al. The hybrid lid crease
                                                                                     approach to address lateral frontal sinus disease with orbital exten-
                                                                                     sion. Ann Otol Rhinol Laryngol 2014;123:826-830. https://doi.
                                                                                     org/10.1177/0003489414538767
A                                  B                                            7
                                                                                     Lim JH, Sardesai MG, Ferreira M Jr, et al. Transorbital neuroendo-
                                                                                     scopic management of sinogenic complications involving the frontal
                                                                                     sinus, orbit, and anterior cranial fossa. J Neurol Surg B Skull Base
                                                                                     2012;73:394-400. https://doi.org/10.1055/s-0032-1329617
                                                                                8
                                                                                     Miller C, Berens A, Patel SA, et al. Transorbital approach for improved
                                                                                     access in the management of paranasal sinus mucoceles. J Neurol Surg
                                                                                     B Skull Base 2019;80:593-8. https://doi.org/10.1055/s-0038-1676982
                                                                                9
                                                                                     Rychen J, Croci D, Roethlisberger M, et al. Minimally invasive al-
C                  D                   E                  F                          ternative approaches to pterional craniotomy: a systematic review
                                                                                     of the literature. World Neurosurg 2018;113:163-179. https://doi.
                                                                                     org/10.1016/j.wneu.2018.02.016
                                                                                10
                                                                                     Jeon C, Hong CK, Woo KI, et al. Endoscopic transorbital surgery
                                                                                     for Meckel’s cave and middle cranial fossa tumors: surgical tech-
                                                                                     nique and early results. J Neurosurg 2018 Nov 1;1-10. https://doi.
G                                  H
                                                                                     org/10.3171/2018.6.JNS181099. Online ahead of print.
                                                                                11
                                                                                     Dallan I, Di Somma A, Prats-Galino A, et al. Endoscopic transorbi-
                                                                                     tal route to the cavernous sinus through the meningo-orbital band: a
                                                                                     descriptive anatomical study. J Neurosurg 2017;127:622-629. https://
                                                                                     doi.org/10.3171/2016.8.JNS16465
                                                                                12
                                                                                     Di Somma A, Andaluz N, Cavallo LM, et al. Supraorbital vs endo-
                                                                                     orbital routes to the lateral skull base: a quantitative and qualitative
                                                                                     anatomic study. Oper Neurosurg (Hagerstown) 2018;15:567-576.
                                                                                     https://doi.org/10.1093/ons/opx256
Figure 4. Multipanel figure showing the radiological pre- and post-operative
imaging (A-B; G-H) and the intra-operative endoscopic view (C-F) of a right
                                                                                13
                                                                                     Lee MH, Hong SD, Woo KI, et al. Endoscopic endonasal versus
spheno-orbital meningioma treated with a multiportal transnasal-transorbital         transorbital surgery for middle cranial fossa tumors: comparison
endoscopic-assisted approach.                                                        of clinical outcomes based on surgical corridors. World Neurosurg
                                                                                     2019;122:e1491-e1504. https://doi.org/10.1016/j.wneu.2018.11.090
                                                                                14
                                                                                     Lin BJ, Ju DT, Hsu TH, et al. Quantitative comparison of endo-
                                                                                     scopically-assisted endonasal, sublabial, and transorbital transmax-
perform a 360° approach to complex skull base lesions.                               illary approaches to the anterolateral skull base. Clin Otolaryngol
When approaching this kind of patient a multidisciplinary                            2021;46:123-130. https://doi.org/10.1111/coa.13559
evaluation and management is strongly advisable, since the
                                                                                15
                                                                                     Saraceno G, Agosti E, Qiu J, et al. Quantitative anatomical com-
                                                                                     parison of anterior, anterolateral and lateral, microsurgical and en-
merger of the different skills fits much better with the need                        doscopic approaches to the middle cranial fossa. World Neurosurg
of the patient.                                                                      2020;134:e682-e730. https://doi.org/10.1016/j.wneu.2019.10.178
Anyway, in our opinion, there is no better approach over                        16
                                                                                     Kong DS, Kim YH, Hong CK. Optimal indications and limita-
                                                                                     tions of endoscopic transorbital superior eyelid surgery for sphe-
another and the choice must always consider several ele-                             no-orbital meningiomas. J Neurosurg 2020 Jun 5;1-8. https://doi.
ments such as the surgeon’s confidence and preference, the                           org/10.3171/2020.3.JNS20297. Online ahead of print.
location of the disease, the purpose of surgery.                                17
                                                                                     Park HH, Hong SD, Kim YH, et al. Endoscopic transorbital and en-




                                                                                                                                                         S65
I. Dallan et al.




     donasal approach for trigeminal schwannomas: a retrospective mul-            transorbital transnasal endoscopic approach for the management of
     ticenter analysis (KOSEN-005). J Neurosurg 2020;133:467-476.                 selected skull base lesions: preliminary experience. World Neurosurg
     https://doi.org/10.3171/2019.3.JNS19492                                      2015;84:97-107. https://doi.org/10.1016/j.wneu.2015.02.034
18
     Locatelli D, Pozzi F, Turri-Zanoni M, et al. Transorbital endoscopic    22
                                                                                  Alqahtani A, Padoan G, Segnini G, et al. Transorbital transnasal en-
     approaches to the skull base: current concepts and future perspec-           doscopic combined approach to the anterior and middle skull base:
     tives. J Neurosurg Sci 2016;60:514-525.                                      a laboratory investigation. Acta Otorhinolaryngol Ital 2015;35:173-
19
     Battaglia P, Turri-Zanoni M, Dallan I, et al. Endoscopic endonasal           179.
     transpterygoid transmaxillary approach to the infratemporal and upper   23
                                                                                  Di Somma A, Langdon C, de Notaris M, et al. Combined and si-
     parapharyngeal tumors. Otolaryngol Head Neck Surg 2014;150:696-              multaneous endoscopic endonasal and transorbital surgery for a
     702. https://doi.org/10.1177/0194599813520290                                Meckel’s cave schwannoma: technical nuances of a mini-invasive,
20
     Gerges MM, Godil SS, Younus I, et al. Endoscopic transorbital                multiportal approach. J Neurosurg 2020;Jul 10;1-10. https://doi.
     approach to the infratemporal fossa and parapharyngeal space:                org/10.3171/2020.4.JNS20707. Online ahead of print.
     a cadaveric study. J Neurosurg 2019:Nov 1;1-12. https://doi.            24
                                                                                  Tham T, Costantino P, Bruni M, et al. Multiportal combined transorbital
     org/10.3171/2019.7.JNS191743. Online ahead of print.                         and transnasal endoscopic resection of fibrous dysplasia. J Neurol Surg
21
     Dallan I, Castelnuovo P, Locatelli D, et al. Multiportal combined            Rep 2015;76:e291-e296. https://doi.org/10.1055/s-0035-1566126




S66
