J Neurol Surg B Skull Base 2020; 81(04): 385-408
DOI: 10.1055/s-0040-1713941
Surgical Approaches to the Orbit
Review Article

Surgical Approaches to the Orbit: A Neurosurgical Perspective

Zeid Abussuud
1  Department of Neurosurgery (Honorary), Queen Elizabeth Hospital, Birmingham, United Kingdom
,
Shahzada Ahmed
2  Department of ENT, Queen Elizabeth Hospital Birmingham, United Kingdom
,
Alessandro Paluzzi
3  Department of Neurosurgery, Queen Elizabeth Hospital Birmingham, United Kingdom
› Author Affiliations
 

Abstract

Orbital pathologies can be complex to manage surgically. In this article, we describe some of the most common and relevant approaches to orbital tumours. For each approach we describe the appropriate indications, surgical technique, potential complications, and illustrate a case example.


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Introduction

Pearls and Tips
  • While the orbit is a small anatomical space, several structures exist within it necessitating careful pre-operative planning and a multi-disciplinary approach if needed.

  • Adequate pre-operative imaging in the form of computed tomography (CT) and/or magnetic resonance imaging (MRI) is essential for pre-operative planning.

  • Compartment and/or organization of clock-face approaches are useful in the diagnostic process of orbital tumors and with approach selection.

  • The type of approach depends principally on the location of the pathology and the associated anatomical barriers, the histology of the lesion and the surgeon's expertise:

    • Tumors lateral to the optic nerve: can be accessed via external approaches such as lateral orbitotomy and frontotemporal craniotomy.

    • Tumors medial to the optic nerve: can be accessed via medial orbitotomy including the anterior medial micro-orbitotomy.

    • Tumors in the inferior and medial compartments: can be accessed through endoscopic endonasal approaches.

  • Novel endoscopic and combined approaches can help overcome the limitations of traditional approaches to orbital tumors.

The orbit is an anatomically complex region that is affected by heterogeneous pathologies. Treatment can be challenging, necessitating the collective knowledge and skills of neurosurgeons, ENT (ear, nose, and tongue) surgeons, and ophthalmologists. In view of the potential morbidity associated with surgery in this region, careful preoperative planning is critical. The type of approach depends principally on the location of the pathology and the associated anatomical obstacles, the histology of the lesion, and the surgeon's expertise.[1] The overriding principle in orbital surgery is to preserve vision. This is achieved by choosing the most anatomically appropriate surgical approach to avoid manipulation of the optic nerve and its vascular supply.

Pathologies involving the lateral aspect of the orbit, lateral to the optic nerve, are typically accessed via external approaches including lateral orbitotomy and frontotemporal craniotomy (with or without zygomatic osteotomy).[2] [3] Those pathologies involving the medial aspect of the orbit, medial to the optic nerve, are accessed via a medial orbitotomy including the anterior medial microorbitotomy.[3] Surgical access to the inferior and medial compartments, particularly for lesions close to the orbital apex, can be achieved through the endoscopic endonasal approach (EEA).

Combined, these approaches provide 360-degree access to resect, debulk, or biopsy primary intraorbital or paraorbital lesions.[4] [5]

This article will describe some of the most relevant surgical approaches to the orbit including their limitations and potential complications. We will also refer to an algorithm ([Fig. 1]) that was developed to help guide surgeons in choosing the most appropriate approach to orbital pathology after careful consideration of the individual lesion. A summary of approaches to the orbit with their major pros and cons is illustrated at the end of the text in [Table 1]. [Fig. 2] illustrates the key surgical incisions used in approaching orbital pathology.

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Fig. 1 Drawing shows the algorithm developed and published in 2015. The right orbit is used for demonstration of the clock model. A medial transconjunctival approach gives access to the anterior orbit from 1 to 6 o'clock. An endoscopic endonasal approach enables access to the apical compartments, middle and posterior aspects of the orbit between 1 and 7 o'clock. Lateral microorbitotomy enables access to the orbit from 8 to 10 o'clock. A frontotemporal craniotomy with orbital osteotomy gives orbital access from 9 to 1 o'clock and a zygomatic osteotomy extends this access from 6 to 8 o'clock. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 2 An illustration of surgical entry sites into the orbit.
Table 1

Summary of approaches to orbital lesions including the indications for each approach and the associated advantages and disadvantages[2] [19]

Approach

Indication

Advantages

Disadvantages

Superior approaches

 Transfrontal

• Tumors of the optic canal

• Pathologies extending into the cranial cavity

• Optic nerve glioma

• Pathologies lateral to the optic nerve

• Excellent exposure

• Ideal for intraconal pathologies

• Typical complications of intracranial surgery

• Large scar

• Requires brain retraction

 Supraorbital

• Intraconal and extraconal lesions superior to the optic nerve

• Minimally invasive

• Good cosmetic results

• Minimal manipulation of brain and orbital content

• Not limited by tumor size

• Hypothesia if supraorbital nerve is damaged

• Limited exposure

• Frontal sinus contamination

• Not ideal for posterior lesions

 Transfrontal sinus approach

• Trauma

• Frontal sinus tumor

• Extraconal pathology

• Retention cysts

• Minimally invasive

• Risk of infection

• Visible scar

Lateral approaches

 Frontoorbitozygomatic

• Orbital apex tumors

• Lesions of the optic canal

• Lesions near the superior orbital fissure

• Lesions dorsal to the optic nerve

• Lateral intraconal and extraconal lesions

• Excellent and broad exposure

• Typical complications of intracranial surgery

• Large scar

• Requires brain retraction

• Cosmetic: scar is visible in patients with receding hairline (bicoronal flap)

 Pterional

• Orbital decompression

• Lesions near the superior fissure

• Lesions near the inferior fissure

• Cavernous sinus pathology

• If extradural approach, minimal brain retraction

• Typical complications of intracranial surgery

 Lateral orbitotomy

• Laterally placed extraconal tumors

• Orbital apex tumors

• Intraconal tumors lateral or inferior to optic nerve

• Retrobulbar lesions such as cavernomas

• Lacrimal gland tumors

• Middle fossa and cavernous sinus

• Good and wide exposure of the orbit and orbital apex

• Well tolerated

• Visible but minimal scar

• Enophthalmos

Medial approaches

 Medial orbitotomy

• Extraconal tumors medial to the optic nerve

• Traumatic compression of intracanalicular portion of the optic nerve

• No brain retraction

• Access to medial orbital lesions through three corridors (medial inferior, medial central and medial superior)

• Sinus contamination

• Limited exposure

Inferior approach (inferior orbitotomy)

• Subperiosteal lesions

• Extraconal tumors in the inferior orbit

• Direct approach

• Minimally invasive

• Protective of intra-orbital content

• Limited exposure

 Transmaxillary

• Extraconal lesions in the orbital floor

• Tumors invading the maxillary sinus

• No intracranial invasion

• Tolerated well

• Limited exposure

• Unsterile approach

 Transconjunctival

• Inferior and medial lesions

• Tenon's capsule pathology

• Intraconal biopsy

• Cavernomas

• Good cosmetic results

• Not very invasive

• Difficult anatomical orientation

Endoscopic endonasal approaches

 Medial-inferior extraconal approach

• Extraconal medial/inferior lesions

• Sinonasal carcinomas involving the orbit

• Meningiomas (intra/extradural)

• Juvenile nasal angiofibromas

• Good cosmetic results

• Not very invasive

• Fast recovery

• Requires familiarity with endoscopy

 Transmaxillary extraconal approach

• Middle cranial fossa tumors

• Meckel's cave tumors

• Tumors extending to compress the cone; meningiomas and juvenile nasal angiofibromas

• Schwannoma extending to: infratemporal fossa, pterygopalatine fossa or maxillary sinus

• Good cosmetic results

• Not very invasive

• Fast recovery

• Advanced- requires experienced surgical team

 Medial intraconal approach

• Medial inferior and posterior intraconal lesions:

  ▪ Nerve sheath meningiomas

  ▪ Extra ocular schwannomas

  ▪ Hemangiomas

• Metastases

• Overcomes limitations of posterior intraconal access associated with medial orbitotomy

• Good cosmetic results

• Not very invasive

• Fast recovery

• Difficult to keep dissection corridor open

• Requires familiarity with endoscopy

Transorbital neuroendoscopic surgery (TONES)

 Precaruncular approach

• Cavernous sinus pathology

• Optic nerve pathology

• Other structures of the central corridor

• Other: pathology affecting the clivus, suprasellar region, sellar and parasellar regions

• Direct and avascular approach

• Rapid healing with no scarring

• No major complications

• Requires familiarity with endoscopy

• Narrow window for instrumentation

 Preseptal lower eyelid approach

• Access to inferior orbit

• Can be combined with lateral retrocanthal approach or precaruncular approach to access the lateral or medial orbit

• Orbital floor tumors or fractures

• Maxillary sinus pathology

• Foramen rotundum pathology

• Minimal risk of orbital fat herniation into surgical field

• No major complications

• Requires familiarity with endoscopy

• Narrow window for instrumentation

 Superior eyelid crease approach

• Anterior fossa pathology

• Frontal sinus pathology

• Orbital roof fractures

• Minimally invasive

• Hidden incision when patient's eyes are open

• Provides dissection in natural anatomical planes

• Enophthalmos (uncommon)

• Requires familiarity with endoscopy

• Narrow window for instrumentation

 Lateral retrocanthal approach

• Access to deep orbit

• Cavernous sinus pathology

• Middle fossa pathology

• Infratemporal fossa pathology

• Allows accessing further centrally located areas such as the lateral cavernous sinus and the middle cranial fossa

• Minimally invasive

• No major complications

• Requires familiarity with endoscopy

• Narrow window for instrumentation


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Surgery in the Orbit—Orbital Approach Overview and Selection

Medial Orbitotomy Approach (Transconjunctival/Transcaruncular)

Dealing with medial orbital tumors can be problematic with standard neurosurgical (transcranial) approaches. The need for a more direct and shorter route approach led to the development of the anterior medial approach. Lynch was the first to describe the transcutaneous approach to the medial orbit and frontal sinus in 1921.[6] The classical Lynch approach with a medial transcutaneous incision is still considered as a main approach to the medial orbit and several variations have been described. More recent approaches include the transconjunctival medial orbitotomy and the transcaruncular approach.

A transconjunctival anteromedial microorbitotomy ([Figs. 3] and [4]) permits access to lesions in the anterior and medial orbit.[3] The approach is suitable for tumors located adjacent to the globe surface. It leaves no visible scars. The approach, however, is not appropriate for deep, superior intraconal, and extraconal lesions.[7] [8] [9] Medial orbitotomies are excellent for evacuation and drainage of mucoceles associated with orbital invasion of benign or malignant processes involving the paranasal sinuses.[7] Additionally, the approach is excellent for optic nerve sheath fenestration, optic nerve incisional biopsies, medial intraconal biopsies, and inferomedial orbital decompression.[3] [7]

Zoom Image
Fig. 3 Images demonstrating a medial microorbitotomy. (A) This approach gives access to lesions located anterior and medial in the orbit. (B) An eyelid retractor is placed, and local anesthetic injected where the peritomy will be performed. (C) After the conjunctiva is incised around the cornea and relaxing conjunctival incisions are made, the medial rectus muscle is detached and (D) retracted medially with a suture. (E) The globe is retracted laterally and the intraconal fat exposed. (F) After the lesion has been excised, the medial rectus muscle is reattached at its insertion site on the globe with a 6–0 absorbable suture, and the conjunctiva is closed with interrupted sutures. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
Zoom Image
Fig. 4 (A) Transconjunctival incision - horizontal incision at 3– to 4 mm inferior to lower eyelid margin, approximately 2.5 cm. (B) Demonstration of some of Horner's muscle.

The need for safe and direct access to the medial orbit with minimal morbidity lead to the development of the transcaruncular approach ([Fig. 5]). The approach was first described by Shorr et al in 2000. In recent years, however, the approach has become more popular. It is regarded as an extension of the transconjunctival approach.[10] The transcaruncular approach offers good exposure to the medial wall, as does the Lynch approach. This approach, however, provides an alternative path to the posterior lacrimal crest. Compared with the classical Lynch approach, the transcaruncular approach is associated with less scarring and less webbing. As a result, it has largely replaced Lynch's approach. Combining this approach with a transconjunctival or transnasal approach enables insertion and manipulation of implants through a small incision, particularly in the setting of medial wall orbital fractures.[6]

Zoom Image
Fig. 5 Schematic representation of approaching the medial orbit through a transcaruncular approach. (A) Dissection begins between the caruncle (globular nodule in the medial canthus of the eye) and plica semilunaris (fold in the bulbar conjunctiva of the medial cantus of the eye). (B) Dissection extends into the subperiosteal space. (Adapted from Graham et al.)[5]
Zoom Image
Fig. 6 The illustration demonstrates the close proximity of the central retinal artery to the optic nerve and the globe. The ophthalmic artery forms the first branch of the internal carotid artery (ICA). The ophthalmic artery splits into the posterior ciliary and central retinal arteries that supply the eye.

In the clock face model ([Fig. 1]) medial orbitotomies provide access to the area between 1 and 6 o'clock.

Approach Limitations and Complications

A transconjunctival medial orbitotomy (without ethmoidectomy) is not suitable for deeply situated intraconal lesions and extraconal superior lesions. Lateral traction of the globe, if extreme, can impact on ocular perfusion pressure leading to visual loss. A lateral orbitotomy, if the lesion is located medially in the center of the surgical space, can permit the globe to be retracted further laterally, and provide adequate exposure.[7] Uncommonly, the optic nerve can be impacted due to the close proximity of the central retinal artery that enters the optic nerve medially, approximately 10 mm posterior to the globe ([Fig. 6]).[7] The transconjunctival approach, however, does not deliver a satisfactory view of the entire medial orbit which can be overcome by using the transcaruncular approach alone (to expose the medial wall only) or a combination of the two approaches to expose the medial and inferior orbit.[10] [11]

The transcaruncular approach allows excellent exposure of the orbital apex and medial orbit. Functional deficit secondary to an injury to the inferior oblique muscle is possible if the bony attachment is not identified appropriately during the muscle release process.[6] Additionally, it is essential that the surgeon follows the proper dissection plane to the posterior lacrimal crest to minimize the risk of injury to the lacrimal apparatus. Insertion and manipulation of a surgical implant using this approach can be challenging due to the small incision. Combining the approach with a transnasal or transconjunctival approach can help overcome this problem.[6]


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Case Example

A 17-year-old male was accidently shot in the orbit with a BB gun ([Fig. 7]). His presenting complaint was pain at gaze extremities associated with photophobia. He had normal visual acuity and visual fields. The anterior location of the foreign body made it accessible via a medial microorbitotomy. His pain improved postoperatively, but he still complained of residual photophobia when he was last followed-up.

Zoom Image
Fig. 7 A coronal computed tomography (CT) image demonstrates the position of a foreign body located between the 2 and 3 o'clock positions in the anterior orbit.[3]

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Transpalpebral Approach

The transpalpebral approach offers a minimally invasive alternative to a frontotemporal craniotomy, providing similar access to the orbital roof and the lateral aspect of the orbit.

The main advantages of this approach are as follows: (1) avoidance of coronal skin flaps, (2) good access to the orbital roof, and (3) minimal cosmetic scarring.[12]

It also provides a pathway to expose the anterior cranial fossa, parasellar space, and frontal sinus.[13] The transpalpebral incision, adopted from oculoplastics, has been paired with many keyhole or minimally invasive approaches, namely, the supraorbital craniotomy to reduce morbidity and improve surgical exposure.[14] Schmidt et al identified a relative safe zone in their paper that is free of nerve (frontalis) branches. The zone exists up to 2.5-cm lateral to the lateral canthus ([Fig. 8]).[15]

Zoom Image
Fig. 8 The figure demonstrates the safe zone for lateral orbital incision described by Schmidt et al.[15] This can be defined by using the predicted paths of the zygomatic and temporal branch of facial. The temporal nerve in their study had a mean distance of 2.8 cm superior to the lateral canthus and the zygomatic nerve had a mean distance 1.7 cm inferior to the temporal nerve at the point of insertion into orbicularis oculi muscle. (Adapted from Schmidt et al.[15])

Approach Limitations and Complications

A transpalpebral approach might limit the use of microsurgical instruments due to space constraints. Additionally, the approach confines trajectory options and may have inadequate illumination.[13] Several potential complications have been reported including periorbital edema, cerebrospinal fluid (CSF) leak, and eyelid hematomas.[12] [16] Careful preoperative planning is important in reducing morbidity and complications. Precise localization of the supraorbital notch minimizes the risk of injury to the supraorbital artery and nerve and the associated complications with their injury. Planning is also required to minimize the risk of frontal sinus penetration in association with dural penetration, should this occur, repair may be more difficult with this approach than with the larger pterional or bicoronal skin flap.[13]


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Endoscopic Endonasal approach (EEA)

In the clock-face model ([Fig. 1]), the EEA accesses the area between 1 and 7 o'clock. The use of the endoscope enables safe and unparalleled visualization of the orbit (especially in areas of difficult access that otherwise require bone removal for a satisfactory view). Endonasal approaches to the orbit have been implemented in collaboration with otolaryngologists and ophthalmologists to facilitate dealing with orbital fractures and lesions behind the globe in the inferomedial orbit, especially toward the orbital apex.[17] It is also an excellent approach for orbital decompression (e.g., in thyroid eye disease) or for optic nerve decompression at the bony canal.[18] [19] [20] [21] [22] [23]


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Surgical Technique

Medial-Inferior Extraconal Approach

This is the most established EEA, particularly with intradural and extradural meningiomas, juvenile nasal angiofibromas, and sinonasal carcinomas involving the orbit.[19]

In the case of small medial extraconal tumors, a uninarial approach can be adopted with preservation of the middle turbinate. Anterior pathologies are best accessed via the ipsilateral nostril to minimize resection of the septum. If extensive instrument manipulation is needed, or if intraconal involvement is present, a binarial approach is useful.[19]


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Transmaxillary Extraconal Approach

This approach is added for treatment of inferior extraconal lesions located between 4 and 7 o'clock ([Fig. 1]). A medial maxillectomy is added to increase access to the orbital floor and associated orbital contents.


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Medial Intraconal Approach

This approach is suitable for intraconal lesions located inferomedially or posteriorly including metastases, extraocular nerve schwannomas, hemangiomas, and nerve sheath meningiomas. The approach overcomes the limitations of the anterior medial orbitotomy for posterior intraconal pathologies.


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Transnasal Optic Nerve Decompression

Several nontraumatic pathologies can affect the optic nerve including: tumors, pseudotumor cerebri (idiopathic intracranial hypertension), infection, bone dysplasia, and endocrine orbitopathies.[24] Transnasal optic decompression can be an initial step prior to treating the underlying cause through an open craniotomy or can be part of the definitive treatment of the primary compressive pathology.[24] Potential complications related to the procedure include hemorrhage, carotid injury, diplopia, vision loss, CSF leak, and rarely, meningitis.[25]

Approach Limitations and Complications

The limitations of EEA to inferomedial orbit becomes more obvious if compared with the transcranial approach. The EEA only allows exposure of the inferior and medial aspects of the orbit as opposed to the extensive exposure that the transcranial approach provides (superior, superomedial, and lateral orbital aspects). These approaches are very complementary as, conversely, the transcranial approaches fail to expose the inferomedial aspect of the orbit and the orbital apex. Additionally, endonasal exposure may offer a more limited range of motion in the surgical field compared with standard microsurgical approaches and have their own learning curve.[26]

Safe tumor resection through the EEA requires good understanding of the relevant anatomical landmarks. It is imperative in orbital surgery to avoid crossing the optic nerve and, therefore, tumors localized to the lateral and superior orbit are contraindicated in EEA. There is a risk of retrobulbar hemorrhage and visual disturbance associated with the approach. Nevertheless, the risk can be minimized by accessing the lamina papyracea below the level of the ethmoidal foramina to spare the ethmoidal arteries or taking care to fully ligate or coagulate them. Also, individual muscle function can be preserved by dissecting between the muscle groups rather than through them.[18]

The surgical field is limited in EEA and so hemostasis can be more difficult to achieve. The approach, hence, should be avoided in highly vascular tumors if the surgeon does not have significant experience.[18] One of the major limitations is the lack of atraumatic endonasal muscle retractors.[3] One way to obviate this problem is to adopt a form of “external retraction” by pulling on the rectus muscles with vessel loops around the muscle insertions onto the globe ([Fig. 9B]).

Zoom Image
Fig. 9 Endoscopic endonasal approach. (A) Skull showing the clock model showing the extent of the orbit that can be exposed through this approach. (B) The insertions of the rectus muscles to the globe are identified and controlled with vessel loops. (C) Endoscopic view of the medial aspect of the orbital apex after a portion of the periorbita has been excised. The internal carotid artery (ICA) is visible medially. The window between medial and inferior rectus muscles is “closed.” (D) After external retraction on the medial and inferior rectus muscles by pulling the respective vessel loops, the surgical window in now “open” and the tumor is identified and (E) excised. (F) The periorbital defect is covered with a free mucosal graft harvested from the removed ipsilateral middle turbinate. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

In conclusion, EEA is a generally useful and safe approach. Some of its limitations can be overcome by combining it with other approaches and the use of multidisciplinary surgery.


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Case Study

[Fig. 10A] shows a coronal image of an orbital osteoma located in the 3 to 5 o'clock position. The 25-year-old patient presented with progressive proptosis secondary to a medial orbital osteoma. The osteoma was completely excised through an EEA. The patient's proptosis resolved postoperatively.[3]

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Fig. 10 (A) Coronal computed tomography images (bone window) demonstrating a medial orbital osteoma that was completely excised. (B) Coronal magnetic resonance imaging illustrating an orbital apex angioleiomyoma. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

[Fig. 10B] demonstrates a coronal image of an orbital apex angioleiomyoma located in the 3 to 4 o'clock position. The 26-year-old patient presented with progressive visual loss secondary to optic nerve compression by a lesion located on the medial aspect of the orbital apex. The lesion was posterior and was approached through an EEA. The patient's vision improved postoperatively.[3]


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Lateral Orbitotomy (Eyelid Crease and Lateral Canthotomy)

The lateral orbitotomy was first described in 1889 by Kronlein and was modified by Bereke (Chabot et al).[27] The approach delivers good exposure to the lateral, superior, and inferior intraconal compartments.[28] It is ideal for purely lateral lesions located in the 8 to 10 o'clock position ([Fig. 1]).[3] It is a practical approach for dealing with retrobulbar tumors (e.g., hemangiomas), lesions lateral to the optic nerve, and tumors of the lacrimal gland. The approach is, nevertheless, more challenging for tumors with intracranial extension.[2] [29] The approach has also been described in treatment of maxillary nerve schwannomas or associated tumors with intracranial extensions.[27] [30] It can also be used for inflammatory processes requiring orbital decompression such as Graves' disease.[27] The approach has been established as an effective method of accessing large deep lesions providing excellent postoperative cosmetic results. It is less invasive than the transcranial approach and offers the option of adding an osteotomy, if clinically indicated.[2] The approach is illustrated in ([Fig. 11]).

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Fig. 11 Lateral orbitotomy. (A) The approach is ideal for lesions located in the 8 to 10 o'clock position lateral to the optic nerve. (B) Small cantholysis incision is made with Steven's scissors along the skin crease. (C) Temporalis muscle is detached and retracted laterally; the lateral wall of the orbit can be appropriately exposed if adequate retraction is present. Reciprocating saw is used to perform the osteotomies. (D) The orbitotomy has been completed and a monopolar was used to cut the last fibers of the temporalis muscle. (E) Periorbita is opened and the tumor is resected. (F) Penrose drain secured in place. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

Approach Limitations and Complications

This approach is contraindicated for pathologies within the optic canal due to the potential for lateral rectus paresis, ptosis, and/or orbital hemorrhage. The incision, for some, may be visible, particularly in younger individuals who do not wear glasses. There is a theoretical risk of causing an injury to the frontal branch of the facial nerve if the incision is not within the recommended anatomical landmarks.[19] During this approach, the surgeon must be cautious when going superiorly to avoid an injury to the lacrimal nerve and/or artery. The surgeon may also encounter the short ciliary nerves, the superior branch of the oculomotor nerve, and the posterolateral ciliary artery, in addition to the branches to the levator palpebrae superioris muscle and the lateral rectus muscle. Finally, when traversing below the lateral rectus, there is an additional risk of injuring the ciliary artery and nerves and the inferior division of the oculomotor nerve.[29]


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Case Examples

[Fig. 12] demonstrates the case of a 68-year-old man that was initially treated for a growth hormone (GH) secreting tumor, resected via an EEA. The patient was then noted to have a mild unilateral optic neuropathy with decreased light saturation, increased lacrimation, mild ptosis, and strabismus. A subsequent MRI demonstrated a well-circumscribed lesion in the lateral aspect of the orbit, superficial to the window between the superior and lateral rectus muscle with a degree of calcification, suggestive of a benign process. The superficial and lateral location of the tumor made it amenable to resection via a lateral orbitotomy. The pathology was confirmed to be an extraconal pleomorphic adenoma of the lacrimal gland and all of the patient's symptoms improved.[3]

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Fig. 12 Coronal computed tomography image demonstrating an extraconal pleomorphic adenoma of the lacrimal gland in the 8 to 10 o'clock position amenable to a lateral orbitotomy. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

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Transcranial Approaches

Tumors involving the lateral orbit are typically approached by external open techniques. The approaches include the frontotemporal orbitozygomatic craniotomy (FTOZ); it is indicated in infiltrative processes or large posterior tumors and in cases where tumors cross between the orbital and cranial compartments.[29] [31] [32] The frontotemporal craniotomy can be with or without an orbitotomy and with or without a zygomatic osteotomy and a lateral orbitotomy, depending on tumor extension. The addition of a zygomatic osteotomy and lateral orbitotomy allows greater access to inferiorly located structures.[29] The full FTOZ approach is favored in lesions extending into the lateral and superior corridors to facilitate adequate exposure of any intracranial extension and exposure of the lateral limits.[29] The objective of the procedure(s) is to safely remove/debulk the lesion with preservation of normal tissues and to restore normal anatomy and functionality. Additionally, the approach can be adopted to debulk tumors and perform orbital decompression for palliative procedures of nonresectable orbitocranial tumors resulting in optic nerve compression and/or severe proptosis.[30]

The FTOZ is a versatile approach and is useful in skull base surgery providing excellent access to the orbital apex, parasellar region, paraclinoid areas, and the brainstem.[29] A summary of all approaches to the orbit is demonstrated in ([Table 1]).


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Surgical Technique

Frontotemporal Orbitozygomatic Craniotomy

This approach has multiple variations including a frontal FTOZ, orbitopterional, temporal, and full FTOZ depending on the degree of exposure required. Compared with the pterional and subtemporal approaches, the extent of osseous resection results in a greater exposure. Additionally, the need for brain retraction is minimized in this approach,[29] illustrated in [Fig. 13].

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Fig. 13 Frontotemporal craniotomy with orbitozygomatic osteotomy. (A) Clock model showing the extent of the orbit that can be exposed through this approach. (B) The frontotemporal craniotomy (first piece) has been cut, the temporalis muscle dissected off its anterior attachment and retracted posteriorly, and a malleable retractor inserted between the orbital roof and the periorbita. (C) While protecting the orbit content on one side of the orbital roof and the frontal lobe on the other side with malleable retractors, the final cut over the orbital roof is made with a high-speed drill going laterally toward the inferior orbital fissure. (D) The “second piece” of the orbitozygomatic craniotomy is removed exposing (E) periorbita and periorbital fat. (F) After retraction of muscles and periorbital fat with cotton-tipped applicators, the tumor comes into view (photo taken with operative microscope). (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

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Supraorbital Approach

The supraorbital keyhole (“eyebrow”) craniotomy is a common approach used by neurosurgeons. This minimally invasive approach was first described in 1982 by Jane et al followed by Goldman and Maus.[33] It is ideal for approaching well circumscribed intraconal or extraconal lesions of the superior orbit such as schwannomas and cavernous angiomas.[2] The approach is a minimally invasive extradural approach that achieves excellent cosmetic results and allows adequate brain and orbital manipulation with no limitations caused by the size of the tumor ([Fig. 14]).[19]

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Fig. 14 (A) Incision for supraorbital craniotomy marked on the right eyebrow. (B) Supraorbital craniotomy has been performed preserving the orbital rim and, medially, the supraorbital nerve (arrow). (C) Gentle retraction is applied to the frontal lobe after removal of cerebrospinal fluid from the opticocarotid recess. (D) View after fenestration of a suprasellar arachnoid cyst. (E) Closure with 5.0 ethylon.

Approach Limitations and Complications

In the FTOZ approach, caution must be used when retracting the levator and superior rectus muscles because the innervation to them ramifies and penetrates the muscles on their inner (intraconal) surfaces at approximately the junction of the posterior one-third and anterior two-thirds. It can be difficult to preserve the trochlear nerve with this approach, but this should be attempted. For these reasons, lateral to medial access is recommended to be limited to approximately at the 1 o'clock position.[3]

The bicoronal incision and the subsequent scar exposure can be problematic in patients with a receding hairline.[19]

The supraorbital approach can be associated with a supraorbital nerve injury resulting in hypoesthesia.[19] Uncommonly, it can be associated with frontal sinus contamination. It is limited in exposing posteriorly placed lesions.[2] [19]


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Case Studies

A 78-year-old gentleman presented with progressive visual loss and a visual field defect due to optic chasm compression from a supraseller arachnoid cyst ([Fig. 14] and [15]). Due to the higher risk of a postoperative CSF leak from an EEA and greater access to parasellar cisterns, a minimally invasive supraorbital approach was instead offered. Through this corridor, the arachnoid cyst was fenestrated into the third ventricle. The patient's vision improved postoperatively, and it remains stable for 2 years after the operation.

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Fig. 15 (A) Preoperative coronal, postcontrast T1 magnetic resonance imaging (MRI) scan demonstrating a suprasellar arachnoid cyst (arrow) compressing and displacing the optic chiasm. (B) Postoperative MRI scan 2 years after fenestration of the arachnoid cyst via a supraorbital eyebrow craniotomy

[Fig. 16] illustrates the case of a 48-year-old man that presented with progressive visual disturbance from a cavernous hemangioma located between the superior rectus and superior oblique muscles. The lesion was superior to the optic nerve and was in close proximity to the orbital roof. The lesion was resected through an orbitofrontal craniotomy and the symptoms in the affected eye improved.[3]

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Fig. 16 Coronal T2 magnetic resonance imaging demonstrating an intraconal cavernous hemangioma located in the 12 to 1 o'clock position resected through a frontotemporal craniotomy and orbitotomy. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

[Fig. 17] demonstrates a case of a 64-year-old female presenting with rapid unilateral visual loss on a background of congenital blindness in the contralateral eye secondary to a cataract. Imaging demonstrated a lesion consistent with a cavernous hemangioma located inferolateral to the optic nerve and the ophthalmic artery at the orbital apex. Initially, she underwent an endoscopic medial orbital apex bony decompression to decompress the optic nerve. She had complete improvement of her visual fields initially but on weaning her dexamethasone dosing, her symptoms deteriorated again. She underwent a frontotemporal obitozygomatic craniotomy where the exposure extended from inferior orbital fissure (IOF) to superior orbital fissure (SOF). The path to the lesion was between the lateral and inferior rectus muscles. Periorbita was opened superior to the inferior rectus. The short ciliary nerves were attached to the lesion. They had to be dissected leading to postoperative transient mydriasis. The cavernous angioma was completely excised, and the patient's symptoms resolved.[3]

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Fig. 17 Cavernous angioma located in the 6 to 8 o'clock position managed initially with endoscopic orbital decompression followed by a frontotemporal craniotomy with orbitozygomatic osteotomy. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)

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Transorbital Neuroendoscopic Surgery (TONES)

The orbit provides excellent endoscopic access to the skull base and the craniofacial region. Transorbital endoscopic approaches, described by Moe et al can overcome some of the limitations associated with EEA.[34] The approach offers widely spaced bilateral access ports that enable range of motion and instrument manipulation. Additionally, a coplanar approach to the lesion reduces the need for angled endoscopes and instrumentation. Transorbital neuroendoscopic surgery (TONES) also provides excellent access to the orbit in addition to intracranial access including the lateral cavernous sinus and the anterior and middle cranial fossae.[35]

TONES is comprised of a group of minimally invasive procedures that enable access to the orbit and skull base without compromising the eyelid. TONES approaches include the following: (1) preseptal (PS) lower eye lid, (2) precaruncular (PC), (3) superior eyelid crease (SLC), and (4) lateral retrocanthal (LRC) approaches.[36] The SLC access is regarded as the most versatile. Practicing these approaches necessitates proficient knowledge of the relevant anatomical structures, particularly the superficial structures including the levator palpebrae muscle, the orbital septum, and the orbicularis muscle. These structures function in elevation, shape, structure, and contraction of the palpebrae. Additionally, the more cranially located orbicularis muscle blends laterally with the frontalis muscle and medially with the corrugator superficialis. The supraorbital nerve exits the supraorbital foramen medially and the periorbita and its underlying vital structures (intraorbital muscles, optic nerve, ocular bulb, blood vessels, and intra- and extraconal tissue) are encountered on deep dissection.[37] The wide surgical ports that can be established allow adequate exposure of the target area using a standard 4-mm endoscope or microscope.[35]

Surgical Technique

Three of the above-mentioned approaches (LRC, PS, and PC) are performed behind the structures of the eyelid. SLC, however, is approached through the skin of the superior eyelid.[34] The SLC approach permits access to the anterior cranial fossa and the orbital roof. The PC approach offers access to the anterior cranial fossa, lateral nasal cavity, cavernous sinus, and the optic nerve. The LRC provides access to the deep orbit, cavernous sinus, middle cranial fossa, and infratemporal fossa. The PS approach provides access to the middle fossa floor (including the foramen rotundum), the orbital floor, the IOF, and the infraorbital nerve ([Fig. 18]).[36]

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Fig. 18 The diagram illustrates the four access quadrants of the orbit. (A) Superior eyelid crease (SLC), (B) precaruncular (PC), (C) preseptal lower eye lid (PS), (D) lateral retrocanthal (LRC) approaches. (Adapted from Ramakrishna et al.[36])

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Superior Eyelid Crease Approach

The approach is useful for management of pathologies of the frontal sinus (including posterior wall fractures with CSF leaks), anterior fossa pathologies, and management of orbital roof fractures ([Fig. 19]).

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Fig. 19 The images demonstrate the superior eyelid crease (SLC) approach. (A) The shaded area shows the area of the orbit targeted in the SLC approach. (B) Exposure of the orbital rim followed by incision of the periosteum at the inferior aspect of the rim. Between the periosteum and orbital roof, a cotton-tipped applicator can be used to aid with retraction. An endoscope is used to proceed with dissection. (Adapted from Moe et al.[34])

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Precaruncular Approach

This approach permits for an increased range of motion allowing for improved instrument manipulation. The approach is indicated in cases involving the cavernous carotid artery, the medial aspect of the cavernous sinus, optic nerves, and structures involving the central corridor. It provides direct medial avascular access with minimal risk of scarring[34] ([Fig. 20]).

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Fig. 20 Precaruncular (PC) approach is demonstrated. (A) Targeted area is demonstrated. (B) Demonstrates a conjunctival incision and use of lacrimal probes to retract the eyelids. (C) After exposing the medial orbital wall, the endoscope can aid in the dissection process. (Adapted from Moe et al.[34])

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Lateral Retrocanthal Approach

The shortcomings of the classical lateral orbitotomy can be overcome by using the LRC approach ([Fig. 21]).The approach is a transconjunctival approach that spares the canthus. In this approach, the canthus is retracted laterally. The approach is posterior to the lateral canthal tendon and can be extended from the orbital floor to the orbital roof. In this approach, the lateral margins of the lower and upper eyelids are retracted laterally and the lateral canthal tendon is palpated at the attachment to Whitnall's tubercle. Posterior to this point, an incision through the conjunctiva is made and continued laterally through the periorbita to the orbital wall. The incision continues superiorly and anteriorly parallel to the orbital rim. The dissection is then extended superiorly and inferiorly into the lacrimal gland and orbital content. The procedure provides excellent cosmetic results with no visible scars.[34]

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Fig. 21 Lateral retrocanthal (LRC) approach. (A) Target area is demonstrated. (B) Dashed line demonstrates a conjunctival incision extending posterior to the insertion of the lateral canthal tendon, the tendon is preserved. (C) Endoscopic dissection after exposing the lateral wall. (Adapted from Moe et al.[34])

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Preseptal Approach

The lateral orbit can also be accessed through this approach ([Fig. 22]). Furthermore, for extended access to the medial or lateral orbit, the PS approach can be used in combination with the PC or LRC. The approach is useful in management of pathologies of the orbital floor, maxillary sinus, and foramen rotundum. The PS approach also minimizes the risk of fat herniation into the surgical field.[34]

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Fig. 22 .Preseptal lower eye lid (PS) approach (A) Demonstrates the target area for a PS approach. (B) The lower eyelid retraction indicating conjunctival incisions. (C) After the inferior aspect of the orbital rim is exposed, the periorbita is incised and endoscopic dissection takes place between the orbital floor and periorbita. (Adapted from Moe et al.[34])

Approach Limitations and Complications

Transorbital neuroendoscopic approaches, in general, are contraindicated in the following scenarios: intraocular surgery within 6 weeks, active adnexal infection, scleromalacia, severe corneal ectasia, and ocular ischemic syndromes. The approaches are also relatively contraindicated in other scenarios including shallow orbital anatomy, monocular patients, previous retinal or optic vascular events, corneal ectasia, and glaucoma.[35]

Multiple case series studies demonstrated no major complications after TONES procedures.[34] [36] In the immediate postoperative phase, ocular dysfunction symptoms, without visual dysfunction, are common.[36] The literature does not report any cases of postoperative CSF leak, blindness or permanent visual deficits. Additionally, significant postoperative bleeding and surgical site infections have not been reported. Single cases of ptosis, enophthalmos, and epiphora have been reported.[35]


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Case Examples

[Fig. 23] demonstrates intraoperative images during a TONES procedure (superior lid approach) to resect an intracanal schwannoma.

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Fig. 23 Transorbital neuroendoscopic surgery procedure (superior lid approach) during a resection of an intracanal schwannoma. (A) Skin incision (dashed line); (B/C) sharp dissection to avoid injury to orbicularis oculi; (D) blunt separation of periorbita from orbital roof; (E) after opening the periorbita the tumor (red arrow) is identified and gently dissected off the surrounding orbital fat with the help of a Q-tip; (F) minimal venous bleeding in the surgical bed after removal of the tumor.

A 19-year-old woman who presented with a 2-year history of progressive proptosis and diplopia. Her imaging demonstrated a multilobular osteoma, in the maxillary antrum and encroaching on the medial wall and the orbital floor, displacing the globe, and narrowing the SOF ([Fig. 24A–C]). The lesion was resected endoscopically using navigation guidance and reconstruction was performed through a lateral canthotomy and combined transconjunctival/transcaruncular (retrocaruncular) approach. Postoperative images confirmed accurate plate placement ([Fig. 24C]).

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Fig. 24 . (A) Coronal preoperative computed tomography (CT) image demonstrates an osteoma in in the maxillary antrum and encroaching on the medial wall and the orbital floor. (B) Three-dimensional reconstruction demonstrating satisfactory position of the bespoke plate post-operatively. (C) Postoperative coronal CT image demonstrating complete excision of the osteoma.

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Combined Approaches

Combined approaches to orbital pathology using external and internal or transorbital approaches have been described throughout this text and, therefore, will not be discussed again. However, a brief description of a novel and modern approach, endoscopic orbital transposition, follows.


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Surgical Technique

Endoscopic Orbital Transposition

Endoscopic orbital transposition is a novel and modern approach that has been described to expand EEA access to the supraorbital recess of the frontal sinus and lateral recess lesions. The approach is largely based on a superomedial orbital wall decompression while preserving periorbita. This enables the surgeon to reach further into the lateral recess of the frontal sinus by facilitating lateral displacement of the contents of the orbit.[38] [39] The approach minimizes the risk of infection, minimizes the risk of scarring, and reduces postoperative morbidity and length of hospitalization. However, this approach requires knowledge of frontal sinusotomy techniques (usually Draf IIb or III), often performed by the otorhinolaryngology surgeon.[38] A Draf III approach is the most common; the frontal sinus floor is removed from the lamina papyracea from one side to the other side together with the interfrontal sinus septum to form a wide median drainage of the frontal sinus. A Draf III enables access to lesions localized in the far lateral region of the frontal sinus and permits a “two nostrils, four hands approach.” After a Draf IIb/III is performed, the anterior ethmoidal artery is identified and transected. The upper portion of the lamina papyracea is then exposed, fractured, and removed taking care to preserve the periorbital layer.[38] [39] A flexible retractor is introduced endonasally to lateralize the orbit and the bony aspect of the supraorbital recess is exposed. A diamond burr is used to drill out the superomedial bony orbital wall. To protect the periorbita while drilling the bony aspect of the supraorbital recess, a malleable retractor is introduced transorbitally.[39] To avoid exposing the dura and a subsequent CSF leak, the orbital roof can be removed in the coronal axis passing through the posterior table of the frontal sinus. During detachment of the periorbita and removal of the superomedial bony angle of the orbit, the integrity of the trochlear periorbita should be maintained to preserve extraocular muscle motility. This technique enables surgical access to the far lateral aspect of the frontal sinus by going over the orbit with double-bended surgical instruments and curved shavers or drills. After the procedure is completed, the retractors are removed to enable natural unfolding of the orbit. In cases with a narrow supraorbital recess, a temporary silastic sheath can be used to cover the entire periorbita while drilling the bone.[39]

Approach Limitations and Complications

The approach is contraindicated in the following cases: previous surgery or trauma resulting in distorted anatomy, a small anteroposterior diameter of the frontal sinus and a narrow interorbital distance. The latter reduces maneuverability of surgical instruments. The approach is also contraindicated with the following pathologies: high density of an osteoma (ivory type), malignancy, and inverted papilloma.


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Case Example

A 48-year-old female that presented with recurrent left periorbital abscesses ([Figs. 25] and [26]). She had been treated with three previous surgical drainages and developed diplopia after her second procedure. She underwent a combined procedure including endoscopic orbital transposition.

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Fig. 25 (A) Axial bone window computed tomography scan demonstrating a left frontal sinus mucocele (arrow). (B) Coronal view of the same.
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Fig. 26 Intraoperative endoscopic endonasal view of the most lateral portion of the left frontal sinus after orbit “transposition.”

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The Role of Intraoperative Monitoring of Visual-Evoked Potential (VEP)

Post-operative visual deficits are always a feared complication of surgery involving pathologies of the visual pathways. The risk is present in some intraorbital surgeries but is also present with surgeries dealing with parasellar tumors and aneurysms in addition to temporal and occipital lobe lesions.[40] The literature reports mixed results regarding use of intraoperative VEP. Initial studies demonstrated that monitoring specific VEP properties improved visual outcomes. Other studies, however, considered intraoperative VEP to be unstable and unreliable.[41] A study by Luo et al that analyzed 46 surgeries by monitoring VEP features and checking pre- and postoperative visual function demonstrated that VEP recordings were feasible in 73% of their cohort. The remainder had impaired vision preoperatively. Their final results demonstrated that VEP results were feasible in all patients except patients with severe visual impairment. They also showed that preserved intraoperative VEPs were predictive of preserved postoperative visual outcome.[41] At present, due to the conflicting data and VEP limitations, routine use of intraoperative VEP is yet to be established. VEP recordings are influenced by multiple hemodynamic and physiological parameters including heart rate, blood pressure and pressure. The readings are also influenced by the type of anesthesia delivered. Additionally, constructive use of VEP requires a clear definition of significant parameter changes (latency, morphology, and amplitude) that can influence visual outcomes to be established.[42] At present, we, therefore, do not recommend routine use of intraoperative VEP in intraorbital surgery until further evidence is established.


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Conclusion

Orbital tumors can be challenging to deal with. However, careful preoperative planning and a multidisciplinary team approach can facilitate the safe removal of orbital tumors with minimal complications and good cosmetic and functional results. This can be attained by choosing the most anatomically appropriate surgical approach for the target tumor to minimize or avoid manipulation of the orbital vascular supply and the optic nerve. By using the entire variety of surgical approaches, every aspect of the orbit can be safely accessed obeying these key principles.


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Conflict of Interest

None declared.

Acknowledgments

We would like to acknowledge everyone who contributed to this publication, including the authors of our references. Also, we would like to thank Mileidy Katerine Fernandez Mejia for drawing our illustrations.

Patient Permission

Verbal consent was obtained for publication, but written consent has not been sought as all images are nonidentifiable.



Address for correspondence

Zeid Abussuud, MBChB
University of Otago, New Zealand; MSc trauma sciences (present) University of Birmingham, United Kingdom; Department of Neurosurgery (Honorary Contract), Queen Elizabeth Hospital Birmingham B15 2GW
United Kingdom   

Publication History

Publication Date:
09 September 2020 (online)

© 2020. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany


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Fig. 1 Drawing shows the algorithm developed and published in 2015. The right orbit is used for demonstration of the clock model. A medial transconjunctival approach gives access to the anterior orbit from 1 to 6 o'clock. An endoscopic endonasal approach enables access to the apical compartments, middle and posterior aspects of the orbit between 1 and 7 o'clock. Lateral microorbitotomy enables access to the orbit from 8 to 10 o'clock. A frontotemporal craniotomy with orbital osteotomy gives orbital access from 9 to 1 o'clock and a zygomatic osteotomy extends this access from 6 to 8 o'clock. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 2 An illustration of surgical entry sites into the orbit.
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Fig. 3 Images demonstrating a medial microorbitotomy. (A) This approach gives access to lesions located anterior and medial in the orbit. (B) An eyelid retractor is placed, and local anesthetic injected where the peritomy will be performed. (C) After the conjunctiva is incised around the cornea and relaxing conjunctival incisions are made, the medial rectus muscle is detached and (D) retracted medially with a suture. (E) The globe is retracted laterally and the intraconal fat exposed. (F) After the lesion has been excised, the medial rectus muscle is reattached at its insertion site on the globe with a 6–0 absorbable suture, and the conjunctiva is closed with interrupted sutures. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 4 (A) Transconjunctival incision - horizontal incision at 3– to 4 mm inferior to lower eyelid margin, approximately 2.5 cm. (B) Demonstration of some of Horner's muscle.
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Fig. 5 Schematic representation of approaching the medial orbit through a transcaruncular approach. (A) Dissection begins between the caruncle (globular nodule in the medial canthus of the eye) and plica semilunaris (fold in the bulbar conjunctiva of the medial cantus of the eye). (B) Dissection extends into the subperiosteal space. (Adapted from Graham et al.)[5]
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Fig. 6 The illustration demonstrates the close proximity of the central retinal artery to the optic nerve and the globe. The ophthalmic artery forms the first branch of the internal carotid artery (ICA). The ophthalmic artery splits into the posterior ciliary and central retinal arteries that supply the eye.
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Fig. 7 A coronal computed tomography (CT) image demonstrates the position of a foreign body located between the 2 and 3 o'clock positions in the anterior orbit.[3]
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Fig. 8 The figure demonstrates the safe zone for lateral orbital incision described by Schmidt et al.[15] This can be defined by using the predicted paths of the zygomatic and temporal branch of facial. The temporal nerve in their study had a mean distance of 2.8 cm superior to the lateral canthus and the zygomatic nerve had a mean distance 1.7 cm inferior to the temporal nerve at the point of insertion into orbicularis oculi muscle. (Adapted from Schmidt et al.[15])
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Fig. 9 Endoscopic endonasal approach. (A) Skull showing the clock model showing the extent of the orbit that can be exposed through this approach. (B) The insertions of the rectus muscles to the globe are identified and controlled with vessel loops. (C) Endoscopic view of the medial aspect of the orbital apex after a portion of the periorbita has been excised. The internal carotid artery (ICA) is visible medially. The window between medial and inferior rectus muscles is “closed.” (D) After external retraction on the medial and inferior rectus muscles by pulling the respective vessel loops, the surgical window in now “open” and the tumor is identified and (E) excised. (F) The periorbital defect is covered with a free mucosal graft harvested from the removed ipsilateral middle turbinate. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 10 (A) Coronal computed tomography images (bone window) demonstrating a medial orbital osteoma that was completely excised. (B) Coronal magnetic resonance imaging illustrating an orbital apex angioleiomyoma. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 11 Lateral orbitotomy. (A) The approach is ideal for lesions located in the 8 to 10 o'clock position lateral to the optic nerve. (B) Small cantholysis incision is made with Steven's scissors along the skin crease. (C) Temporalis muscle is detached and retracted laterally; the lateral wall of the orbit can be appropriately exposed if adequate retraction is present. Reciprocating saw is used to perform the osteotomies. (D) The orbitotomy has been completed and a monopolar was used to cut the last fibers of the temporalis muscle. (E) Periorbita is opened and the tumor is resected. (F) Penrose drain secured in place. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 12 Coronal computed tomography image demonstrating an extraconal pleomorphic adenoma of the lacrimal gland in the 8 to 10 o'clock position amenable to a lateral orbitotomy. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 13 Frontotemporal craniotomy with orbitozygomatic osteotomy. (A) Clock model showing the extent of the orbit that can be exposed through this approach. (B) The frontotemporal craniotomy (first piece) has been cut, the temporalis muscle dissected off its anterior attachment and retracted posteriorly, and a malleable retractor inserted between the orbital roof and the periorbita. (C) While protecting the orbit content on one side of the orbital roof and the frontal lobe on the other side with malleable retractors, the final cut over the orbital roof is made with a high-speed drill going laterally toward the inferior orbital fissure. (D) The “second piece” of the orbitozygomatic craniotomy is removed exposing (E) periorbita and periorbital fat. (F) After retraction of muscles and periorbital fat with cotton-tipped applicators, the tumor comes into view (photo taken with operative microscope). (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 14 (A) Incision for supraorbital craniotomy marked on the right eyebrow. (B) Supraorbital craniotomy has been performed preserving the orbital rim and, medially, the supraorbital nerve (arrow). (C) Gentle retraction is applied to the frontal lobe after removal of cerebrospinal fluid from the opticocarotid recess. (D) View after fenestration of a suprasellar arachnoid cyst. (E) Closure with 5.0 ethylon.
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Fig. 15 (A) Preoperative coronal, postcontrast T1 magnetic resonance imaging (MRI) scan demonstrating a suprasellar arachnoid cyst (arrow) compressing and displacing the optic chiasm. (B) Postoperative MRI scan 2 years after fenestration of the arachnoid cyst via a supraorbital eyebrow craniotomy
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Fig. 16 Coronal T2 magnetic resonance imaging demonstrating an intraconal cavernous hemangioma located in the 12 to 1 o'clock position resected through a frontotemporal craniotomy and orbitotomy. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 17 Cavernous angioma located in the 6 to 8 o'clock position managed initially with endoscopic orbital decompression followed by a frontotemporal craniotomy with orbitozygomatic osteotomy. (Reprinted with permission from Paluzzi A, Koutourousiou M, Tormenti M, et al. “Round-the-Clock” Surgical Access to the Orbit. Journal of Neurological Surgery Part B: Skull Base. 2014;73(S 02):12–24. doi:10.1055/s-0032-1314033)
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Fig. 18 The diagram illustrates the four access quadrants of the orbit. (A) Superior eyelid crease (SLC), (B) precaruncular (PC), (C) preseptal lower eye lid (PS), (D) lateral retrocanthal (LRC) approaches. (Adapted from Ramakrishna et al.[36])
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Fig. 19 The images demonstrate the superior eyelid crease (SLC) approach. (A) The shaded area shows the area of the orbit targeted in the SLC approach. (B) Exposure of the orbital rim followed by incision of the periosteum at the inferior aspect of the rim. Between the periosteum and orbital roof, a cotton-tipped applicator can be used to aid with retraction. An endoscope is used to proceed with dissection. (Adapted from Moe et al.[34])
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Fig. 20 Precaruncular (PC) approach is demonstrated. (A) Targeted area is demonstrated. (B) Demonstrates a conjunctival incision and use of lacrimal probes to retract the eyelids. (C) After exposing the medial orbital wall, the endoscope can aid in the dissection process. (Adapted from Moe et al.[34])
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Fig. 21 Lateral retrocanthal (LRC) approach. (A) Target area is demonstrated. (B) Dashed line demonstrates a conjunctival incision extending posterior to the insertion of the lateral canthal tendon, the tendon is preserved. (C) Endoscopic dissection after exposing the lateral wall. (Adapted from Moe et al.[34])
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Fig. 22 .Preseptal lower eye lid (PS) approach (A) Demonstrates the target area for a PS approach. (B) The lower eyelid retraction indicating conjunctival incisions. (C) After the inferior aspect of the orbital rim is exposed, the periorbita is incised and endoscopic dissection takes place between the orbital floor and periorbita. (Adapted from Moe et al.[34])
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Fig. 23 Transorbital neuroendoscopic surgery procedure (superior lid approach) during a resection of an intracanal schwannoma. (A) Skin incision (dashed line); (B/C) sharp dissection to avoid injury to orbicularis oculi; (D) blunt separation of periorbita from orbital roof; (E) after opening the periorbita the tumor (red arrow) is identified and gently dissected off the surrounding orbital fat with the help of a Q-tip; (F) minimal venous bleeding in the surgical bed after removal of the tumor.
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Fig. 24 . (A) Coronal preoperative computed tomography (CT) image demonstrates an osteoma in in the maxillary antrum and encroaching on the medial wall and the orbital floor. (B) Three-dimensional reconstruction demonstrating satisfactory position of the bespoke plate post-operatively. (C) Postoperative coronal CT image demonstrating complete excision of the osteoma.
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Fig. 25 (A) Axial bone window computed tomography scan demonstrating a left frontal sinus mucocele (arrow). (B) Coronal view of the same.
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Fig. 26 Intraoperative endoscopic endonasal view of the most lateral portion of the left frontal sinus after orbit “transposition.”