Keywords

Introduction

In 1888, Kronlein introduced the concept of lateral orbital rim removal to access deep orbital lesions. While this approach is still employed to this day, today’s aesthetically oriented orbital surgeon has a myriad of new minimally invasive techniques in their armamentarium. Orbital imaging continues to improve with more sensitive and higher-resolution computed tomography (CT) and magnetic resonance imaging (MRI) scanning technologies. Multidisciplinary collaborations have facilitated newer surgical approaches through the sinuses and transcranial routes. Technological advancements in the instrumentation of today’s orbital surgeon have also improved in the 15 years since the last edition of this chapter. Finally, advances in anesthesia techniques have allowed more cases to be performed in an outpatient setting with less sedation.

Preoperative Assessment

Age and Race

Patient age is an important factor in the surgeon’s decision-making. An infant’s orbital structure is softer than the adult one, allowing the use of different instrumentation if the bone needs to be cut. The infant orbit is also shallow and allows easier access to deep lesions, if necessary, through skin or conjunctival incisions. Particular caution should be exercised to maximize aesthetic outcomes to minimize social factors in a child’s development. Surgical wounds should be meticulously reapproximated to reduce scarring of the skin and conjunctival symblepharon formation, which form more exuberantly in younger patients.

Older patients present different considerations. With increasing age, tissues become more lax and fragile. While this increased laxity allows for creation of smaller incisions and greater surgical access, there is a higher tendency for bleeding and postoperative eyelid malpositions. Attention should be paid toward deficiency of the anterior lamella and addressing any eyelid laxity at the time of surgery. Past medical history should be reviewed to understand the immune status of the patient, tendency to bleed, and risks in general anesthesia. Diseases affecting wound healing, such as diabetes, should be taken into consideration when deciding on wound closure and to avoid dehiscence. The shape of the cranium, contour, and bone thickness are influenced by racial characteristics. These differences are well demonstrated in different imaging techniques and may influence decision-making in terms of approach and bone removal.

Patients of Asian descent and those with darker skin are more prone to develop hyperpigmentation, hypertrophic scars, and keloid. If possible, a conjunctival approach should be considered. The use of perioperative antibiotics should be considered in cases with infected sinuses and patients at risk for valvular heart disease.

Use of Anticoagulants

The patient’s coagulation status, bleeding history, clotting parameters, and use of any anticoagulants need to be assessed and adjusted to minimize the risk of intraoperative or postoperative bleeding. Dietary supplements and certain ethnic foods contain endogenous anticoagulants, and these should be ascertained prior to surgery. The more widespread and prolonged use of newer antiplatelet medications, such as clopidogrel, should also be inquired during the preoperative assessment. Up-to-date bleeding profiles should be performed in any patient taking warfarin. Cessation of any anticoagulant must be performed with consent of the primary care physician or cardiologist. The renewal of these medications should likewise be done under supervision of the primary care physician. Consideration of preoperative type and cross-matching of blood should be performed in patients with extreme tendency to bleed.

Imaging

Orbital surgery of any kind requires preoperative planning. Orbital imaging has become a cornerstone in the preoperative assessment. CT and MRI have replaced plain film X-rays as the standard of care. The advantages of CT imaging include visualizing bony structures, including fractures, erosion of bone due to malignant tumors, and calcifications and rapid identification of hemorrhage. CT is contraindicated in pregnant patients. If there is suspicion of ferromagnetic implants or foreign bodies, CT is the modality of choice. At the time of this chapter’s composition, the use of CT imaging in children is controversial secondary to the radiation risk.

MRI is the favored modality for assessing apical tumors and identifying soft tissue structures. The surface characteristics and imaging contour of a lesion can determine the surgical approach. Many studies have described the different imaging characteristics between malignant and benign tumors. A malignant process can be suspected when a lesion has an irregular shape or is diffuse in nature, molding around normal orbital structures, has perineural involvement, and shows evidence of bony erosion. Features such as oval shape, hyperostosis, hyperintensity on T2, and hyperdensity or hypodensity on CT are likely to characterize benign tumors.

Ultrasound imaging can be used as an adjunctive modality to CT and MRI. It is especially useful with children since it is easily performed, requires a simple setup, and does not typically require sedation. Ultrasound can add to other imaging modalities in specific cases such as assessing flow in capillary hemangiomas.

Anesthesia and Positioning

Orbital surgery may be performed under local or general anesthesia. Biopsy of anteriorly palpable orbital lesions can generally be performed under local anesthesia. All deep orbital lesions and any bone manipulations should be done under general anesthesia.

Local anesthesia is obtained by infiltration with 2% lidocaine and 1:200,000 epinephrine mixed with an equal part of 0.75% bupivacaine. In cases of local anesthesia with monitored care, the prior instillation of opioid minimizes the sneeze reflex commonly seen after propofol sedation and periocular injection. The local anesthetic is given at least 10 min before preparing for surgery to allow time for maximal vasoconstriction. Additional blocks of the supratrochlear, supraorbital, lacrimal, and infraorbital nerves may be needed for extensive dissection or when the periosteum is involved. IV sedation is used throughout the procedure. The agents employed will depend on the patient’s medical status and the preference of the anesthesiologist. Inhalation of a NO/O2 mixture for 2 min before injection will minimize the sting of local anesthetic agents. If the procedure involves entry into the nasal cavity or sinus, packing of the nose should be done with cocaine or lidocaine and a nasal decongestant. General anesthesia with controlled hypotension is indicated in most patients. Lowering of blood pressure, combined with slight elevation of the head, will decrease operative bleeding and improve operative exposure in the orbital apex.

Instrumentation

Orbital surgery instruments are culled from the ophthalmic, otolaryngologic, and neurosurgical world. The instruments need to be delicate and lengthy to reach deep orbital tissues. The instruments that provide specific needs in orbital surgery are discussed below.

Retractors

Visualization within the tight confines of the orbit is essential for optimal outcomes. A variety of retractors are utilized in orbital surgery. Senn and Desmarres retractors are used for skin and eyelid margin retraction (Fig. 46.1a). The Senn retractor has an extended reach compared to the Desmarres and provides deeper retraction. The curved face of the Desmarres retractor minimizes trauma to the eyelid and is useful for retraction of the lower eyelid for inferior orbitotomy approaches. Silk traction sutures can be placed as needed for further exposure. Malleable retractors of various widths can be bent to shape and used for retraction in the orbit (Fig. 46.1b). Often, prolapse of orbital fat obscures visualization in the orbit. Neurosurgical cottonoids can be placed against the malleable retractor to provide additional retraction of orbital fat (Fig. 46.1c, d).

Fig. 46.1
figure 1

(a) Various sizes of Senn (top) and Desmarres (bottom) retractors useful for orbital exposure. (b) Various sizes of malleable retractors used for retraction in the orbit. (c, d) Neurosurgical cottonoids useful for retraction of orbital fat. (e) Freer periosteal elevator with sharp and blunt ends. (f) Peanut sponge attached to hemostat clamp (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Periosteal Elevator

A variety of sizes of periosteal elevators can be utilized during orbital surgery. Figure 46.1e shows a Freer periosteal elevator which has a blunt and sharp dissecting edge. This instrument provides delicate separation of bone from the periosteum and can also be used to dissect normal orbital structures from pathologic lesions. Two Freer elevators can be simultaneously used to perform dissection through orbital tissues with one elevator providing countertraction, while the other elevator is used for blunt dissection.

Other Dissectors

The dissection in orbital surgery is typically blunt with the goal of keeping a bloodless field. The main goal in keeping a bloodless field is to improve exposure and visualization. A good dissection can help the surgeon identify the anatomical and pathological structures, and that can also shorten the operating time and the length of general anesthesia. The surgeon can use microdissecting instruments, cotton applicators, or peanut sponges for blunt dissection (Fig. 46.1f).

Drills

Bone cutting instruments are used to facilitate bone dissection, reconstruction, and decompression. High-speed bone cutting instruments are used frequently in orbital surgery. Drills are used to sculpt bones or to create tunnels to stabilize the bone with screws, sutures, or implants. The diamond-tipped burr is well suited to sculpt bone. The 4-mm diamond tip is useful during bony decompression as the high speeds (>40,000 rpm) cause thermal coagulation of marrow bleeding, particularly in the deep lateral orbit. When performing any drilling during orbital surgery, caution should be exerted to avoid collateral damage to the surrounding skin, globe, and orbital tissues. Placement of a corneal protector is an absolute requirement in all cases. Malleable retractors should be used to isolate the globe, and frequent saline irrigation is used to dissipate heat generated during drilling.

Endoscope

The use of rigid endoscopes has become an integral part of orbital surgery, especially when approaching through or to the nasal cavity. The endoscope allows a smaller dissection, with better viewing in the deep orbit. The endoscopes are available in different width and several angulations, from 0° to 90°. High-definition video attachment allows good-quality filming for documentation and teaching purposes.

Cryoprobe

The cryoprobe is a useful tool during orbital surgery. It allows stabilization of a mass in the deep orbit, while other dissectors are used to separate the lesion from the surrounding structures. Both the straight- and side-tip probes can be used depending on the location within the orbit. The surgeon freezes the cryoprobe to the mass and dissects it in a “rolling” technique by manipulating it slowly from its surrounding. The use of cryoprobes has been described for benign, encapsulated, or pseudo-encapsulated tumors such as cavernous hemangioma or neuroma.

Image Guidance Procedures

Intraoperative use of image-guided navigation and interactive application of 3D images has been recently acknowledged by orbital surgeons. In orbital fractures, by matching the contours of the mobile segment with the preoperative plan, computer-assisted navigation can be used to guide fracture reduction. In past years, case reports have been published regarding image guidance orbital procedures for removal of deep orbital foreign bodies, mucoceles, and other masses. Future technical developments will likely improve the application of this modality during orbital surgery.

Biopsy Techniques

Orbital biopsy is performed for suspicious lesions, with the goal of obtaining adequate tissue for histologic identification. Specimens obtained during orbital biopsy can be scant and must be treated with exquisite care. Most specimens from excisional and incisional biopsies can be evaluated with conventional stains such as hematoxylin and eosin (H&E) after formalin fixation, but certain specimens should be submitted “fresh” for preservation of cellular epitopes when antibody-based assays are to be used. Hence, these samples should be placed in normal saline instead of fixatives. Communication with the pathologist prior to the biopsy should be performed when there are any concerns about histologic studies.

Fine-Needle Aspiration Biopsy

The use of fine-needle aspiration biopsy in the diagnosis of orbital tumors was introduced in Sweden in 1975. Eligible patients include those with deep orbital lesions not amenable to resection or poor candidates for general anesthesia and wide incision for biopsy. The greatest value of fine-needle aspiration biopsy appears to be in patients with known metastatic disease and a deep orbital lesion suspected of being metastatic. Fine-needle aspiration biopsy can confirm the diagnosis with minimal morbidity and, in some cases, can help the oncologist plan for radiation therapy, chemotherapy, or ablative endocrine therapy. Its use has also been advocated to differentiate meningiomas from low-grade and malignant astrocytomas in patients with optic nerve tumors and blind eyes. In many cases, however, these lesions can be diagnosed by clinical history and CT imaging. Fine-needle aspiration can also be used for muscle biopsies in the orbit. The diagnostic accuracy of fine-needle aspiration biopsy is dependent on the cytopathologist interpreting the material. In skilled hands, there is a diagnostic accuracy of up to 92%.

The technique involves the use of a 22–23-gauge disposable needle on a 20-mL syringe. A needle is introduced into the mass and aspiration is applied. The needle is moved back and forth, producing a cutting action under pressure. Biopsies of intraconal lesions can be performed under simultaneous CT or ultrasonic image guidance. The procedure can be performed under either general or local anesthesia. The needle aspirate is placed on a frosted slide, quickly fixed in 95% alcohol, and stained according to Papanicolaou’s technique. The main complications of fine-needle aspiration biopsy are globe perforation, orbital hematoma, and optic nerve injury.

Excisional Biopsy

Excisional biopsy refers to total surgical removal of a mass lesion. This technique typically offers a large tissue sample, with the possibility of defining surgical margins, determining whether the lesion was fully excised, and verifying the presence of a capsule or pseudo-capsule surrounding the lesion. In orbital surgery, excisional biopsies are typically performed for lesions which appear well circumscribed on orbital imaging, such as cavernous hemangioma, hemangiopericytoma, fibrous histiocytoma, or schwannoma.

Incisional Biopsy

An incisional biopsy is partial tissue excision of a mass lesion for histopathologic study without complete removal of the mass. The surgeon should be confident that the amount and quality of the biopsy represent the clinically abnormal tissue. The surgeon must also take care to maintain the gross architecture of the tissue without crushing it or using excess cautery. Fragile tumors such as lymphomas and mesenchymal tumors should be handled delicately, especially when using forceps. Incisional biopsy can be used for muscle biopsies, any diffuse orbital mass, and lesions suspicious for lymphoma. For encapsulated lesions of the lacrimal gland, complete excisional removal with capsular integrity is advocated.

Anterior Orbitotomy

Anterior orbital lesions may be accessed through a transconjunctival or transcutaneous approach. The optimal approach depends on multiple factors including the location of the lesion, history of prior surgery, and status of the anterior lamella and conjunctiva. The incision and approach to the orbit should provide adequate exposure for best visualization and safe manipulation of orbital tissues. The approach should be chosen to minimize collateral damage and to maximize cosmesis.

Superior Orbital Lesions: Transcutaneous Approach

The transcutaneous route is the preferred approach for lesions situated in the anterior and superior orbit (Fig. 46.2a). For lesions located in the subperiosteal space, the dissection plane can be performed along the orbital septum and superiorly to the arcus marginalis while keeping the orbital septum intact. Meticulous care should be taken to avoid damage to the levator, superior oblique muscle, trochlea, lacrimal gland, and sensory nerves and vasculature along the superior orbital rim. Alternatively, the orbital septum can be opened superior to its insertion onto the levator aponeurosis. In this manner, the orbital fat and the lacrimal gland may be exposed. Figure 46.3a, b shows an upper eyelid crease approach for removal of an epibulbar dermoid cyst.

Fig. 46.2
figure 2

Sites of surgical entry into the orbit. (a) Upper eyelid crease. (b) Transcaruncular. (c) Inferior transconjunctival. (d) Lateral canthotomy. (e) Frontoethmoidal (Lynch) (remark – not for print) ((c) is the broken line in the lower lid; (d) is the small canthotomy; (e) is Lynch drawn vertically between the medial canthus and the bridge of the nose) (Courtesy of Dr. Arkadi Yakirevitch)

Full size image
Fig. 46.3
figure 3

(a, b) Upper eyelid crease approach for removal of an epibulbar dermoid cyst (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Superior Orbital Lesions: Transconjunctival Approach

The superior transconjunctival approach is less common. Lesions in the superior orbit could be approached usually through a lid crease incision; however, subconjunctival lesions in the superior orbit can be accessed through a superior perilimbal approach (Fig. 46.4). This patient presented for ptosis evaluation, and upon elevation of the eyelid, a salmon-colored lesion was noted in the superior fornix (Fig. 46.5a). An adequate biopsy was obtained for diagnosis through the superior limbal approach (Fig. 46.5b). Of note, the proximity to the lacrimal gland and lacrimal duct openings makes this approach more complicated compared to the eyelid crease incision.

Fig. 46.4
figure 4

Superior perilimbal approach used to approach subconjunctival lesions in the superior orbit (Courtesy of Dr. Arkadi Yakirevitch)

Full size image
Fig. 46.5
figure 5

(a, b) Superior perilimbal approach used during incisional biopsy for a superior salmon patch lesion (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Inferior Orbital Lesions: Transcutaneous Approach

The lower eyelid subciliary incision provides access to the inferior orbit. Although this approach also allows for wide exposure of the orbital floor, it may be complicated by postoperative eyelid malposition such as ectropion and retraction. In select cases of anophthalmic sockets or cicatrizing conjunctival diseases, the transcutaneous approach is utilized. However, in our experience, the more optimal route for access to the inferior orbit is through the inferior transconjunctival incision.

Inferior Orbital Lesions: Transconjunctival Approach

The conjunctival fornix approach is the preferred approach for inferior orbital lesions (Fig. 46.2c). The transconjunctival incision is typically combined with a lateral canthotomy and cantholysis for added exposure (Fig. 46.6a, b). The subconjunctival tissue is dissected down to the inferior orbital rim by sharp and blunt dissection (Fig. 46.6c). A malleable retractor deep to the orbital rim protects the globe while the dissection is performed. At this point, orbital fat may prolapse anteriorly. An anterior orbital lesion might be visualized at this point. A posterior or extensive orbital lesion will require deeper dissection. For lesions in the inferomedial orbit or when further dissection along the medial wall is desired, the inferior oblique can be imbricated with 6–0 vicryl suture and disinserted (Fig. 46.6d, e). Following the completion of surgery, the muscle is reinserted to its site of origin along the maxillary bone. Figure 46.7a, b shows an orbital MRI of an intraconal, circumscribed lesion in the inferolateral orbit. An inferior transconjunctival approach was used to access the lesion, while a cryoprobe was used to facilitate removal of this cavernous hemangioma. The periosteum is not typically closed to facilitate drainage. The inferior conjunctival incision can be closed with fast-absorbing gut suture. The lateral tarsus should be sutured to the periosteum posterior to the lateral orbital rim or to the superior crus of the lateral canthal ligament. The upper and lower lid margins are reapproximated with 7–0 absorbable sutures at the lateral canthal angle.

Fig. 46.6
figure 6

The transconjunctival incision (a) is typically combined with a lateral canthotomy and cantholysis (b). (c) Inferior transconjunctival incision for access to the inferior orbit. (d, e) Disinsertion of the inferior oblique provides excellent access to the medial and inferomedial orbit (Courtesy of Dr. Arkadi Yakirevitch)

Full size image
Fig. 46.7
figure 7

(a, b) Orbital MRI showing a well-circumscribed intraconal mass in the inferolateral orbit (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Medial Orbital Lesions: Transcutaneous Approach

The Lynch incision can be used to approach lesions near the lacrimal sac, ethmoid sinus, or medial rectus. The incision is made approximately 10 mm medial to the medial canthal angle (Fig. 46.2e). A subperiosteal dissection plane is created while the medial canthal tendon is reflected. The Lynch incision has largely been replaced by the transcaruncular approach or endoscopic approach for drainage of ethmoidal abscesses.

Medial Orbital Lesions: Transconjunctival Approach

Access to the muscle cone can be obtained through a transconjunctival medial orbitotomy. The medial orbitotomy involves a circumlimbal conjunctival incision and disinsertion of the medial rectus muscle (Fig. 46.4). The medial rectus muscle can be tied with a double-armed 6–0 vicryl suture for later reattachment (Fig. 46.8). Sutures (4–0 silk) can be placed at the muscle insertion for traction. Extraconal muscle lesions may not require disinsertion of the rectus muscle. Traction sutures can also be used to retract the eyelids. After exposure of the area to be dissected, blunt-tipped scissors are used to spread the orbital septum and separate vital structures and blood vessels. Retractors should help the dissection by pushing away orbital fat, optimizing visualization creating a bloodless surgical field. Lesions may be removed or biopsy specimens obtained using a cryoprobe or bayonet forceps. The surgeon should avoid crushing the biopsy material since that could cause errors in pathologic diagnosis. The final step in the medial conjunctival approach is to attach all transected muscles back to their insertions. The conjunctiva is closed with 8–0 interrupted absorbable sutures. No pressure dressing should be applied. In cases of large nasal intraconal lesions, it is often mandatory to perform a combined medial and lateral orbitotomy with removal of the lateral orbital wall. That allows displacement of the globe temporally, which improves exposure to the nasal portion of the orbit.

Fig. 46.8
figure 8

Disinsertion of the medial rectus for access to the medial orbit (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Medial Orbital Lesions: Transcaruncular Approach

The transcaruncular approach to the medial orbit begins with a dissection through the caruncle (Fig. 46.2b). Dissection is performed posterior to the lacrimal sac and can be used to gain access to the medial orbital wall for fracture repair, orbital decompression, or abscess drainage (Fig. 46.9a, b). This approach provides excellent cosmesis and surgical exposure. Care should be taken to avoid the lacrimal sac and canalicular system.

Fig. 46.9
figure 9

(a, b) Transcaruncular approach to the medial orbit (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Lateral Orbitotomy

Lateral orbitotomy with bone window through a transcutaneous approach provides the best access to the deep orbit (Fig. 46.10). It is ideal for removal of deep masses within the intraconal space, and it aids in reaching small, deep orbital tumors for biopsy. The skin access for a bony orbitotomy can vary depending on the location of the lesion. Berke’s modification of the Kronlein operation involves a lateral canthotomy, with dissection of the upper and lower limbs of the lateral canthal tendon from the orbital rim (Fig. 46.2d). The skin is undermined from the temporalis fascia and retracted with silk sutures. The Stallard-Wright incision is curvilinear, extending from the eyebrow cilia to the zygomatic arch through the lateral bony orbital rim. This approach has largely been replaced by the more cosmetically pleasing upper eyelid crease incision (Fig. 46.2a). The superior and inferior skin flaps are undermined to simplify the closure. After the skin incision has been performed, the periosteum is incised with a scalpel or cutting cautery. The periosteal incision should make full use of the exposure gained by the skin incision. The periosteum is then gently dissected from the lateral orbital wall. Stripping the temporalis muscle from its bony fossa requires a blunt dissection. Cutting cautery can be used in the beginning of the dissection with the advantage being minimal hemorrhage in the operative field. Venous bleeding from the temporal bone can be controlled with pressure or bone wax. The periorbita is then elevated from the inner orbital wall using a Freer elevator. This maneuver should be done gently in order to keep the integrity of the periorbita, especially in cases of benign, mixed lacrimal gland tumor. After the lateral orbital rim is fully exposed, malleable retractors are positioned on both sides to protect the surrounding tissues. Drill holes are made on either side of the intended superior and inferior bone cuts. The upper cut is placed above the frontozygomatic suture (Fig. 46.11). The cut is angled 15° caudally to prevent intracranial entry. The lower cut is placed along the upper margin of the zygomatic arch. Slow irrigation prevents heat necrosis of the bone. The lateral rim fragment is gently rocked and removed. Then it is put in sterile saline for later replacement. The bony opening can be enlarged posteriorly by using rongeurs or drilling with a diamond-tipped burr. The intact periorbita is then incised at the intended location. Orbital dissection should proceed gently with blunt dissection using a combination of malleable retractors and blunt scissors. The lateral rectus muscle should be identified and retracted for an intraconal mass. Excessive traction should be avoided on the lateral rectus muscle, as it may result in a hematoma or an abduction deficit. Orbital dissection should be performed under direct visualization, and any bleeding should be identified and controlled. It is imperative to maintain a dry surgical field. If an incisional biopsy is performed, only partial exposure may be needed. For an excisional biopsy, complete isolation of the mass from the native structures is needed.

Fig. 46.10
figure 10

Schematic showing rim removal marked in lateral orbitotomy (Courtesy of Dr. Arkadi Yakirevitch)

Full size image
Fig. 46.11
figure 11

Superior osteotomy is made above the frontozygomatic suture angling inferiorly. (Reproduced with permission from Javier Servat MD)

Full size image

After the tumor has been removed, the surgeon should assess the field and make sure there is no bleeding. The bony fragment of the lateral wall is placed back in position with a stainless steel or silk suture, passed through the previously drilled holes (Fig. 46.12). In specific situations, the surgeon may elect not to place the bone back, and the absent area of the lateral orbital rim will eventually be replaced by fibrous tissue. A suction drainage system can be placed in the fossa of the temporalis muscle in cases of anticipated high wound secretions. The orbicularis is closed with 5–0 vicryl sutures. The skin is closed with a running suture. A light dressing can be applied over the eye and the skin incision, but they can also be left uncovered. Skin sutures should be removed after 7–10 days.

Fig. 46.12
figure 12

For replacement of the orbital rim, drill holes are placed on both sides of intended bony incision for suture fixation (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Medial Lid Crease Approach to the Orbit and Optic Nerve

This approach deserves special mention. The superior transcutaneous approach also provides excellent access to the superomedial orbit and optic nerve. The medial one-third of the upper eyelid crease can be incised to gain access through this approach. Following dissection through the orbital septum, the dissection is performed between the nasal and central fat pads in a posterior direction. The medial horn of the levator aponeurosis is pushed laterally, and blunt dissection proceeds under the superior oblique muscle tendon, laterally and inferiorly along the medial sclera, to identify the optic nerve. The vortex veins should be identified and avoided, and the ciliary vessels can be helpful landmarks. Figure 46.13a shows the optic nerve exposed through the superomedial lid crease approach. In this case, the optic nerve sheath is fenestrated in a case of progressive optic neuropathy from idiopathic intracranial hypertension (Fig. 46.13b).

Fig. 46.13
figure 13

(a, b) Exposure of the optic nerve through the superomedial lid crease approach. (b) Arrow pointing to the fenestration created in the optic nerve sheath (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

Endoscopic Orbital Surgery

The use of endoscopes in orbital surgery was first described by Norris and Cleasby in 1981. The initial reports described biopsies of orbital tumors and removal of foreign bodies. The advent of endoscopic surgery and intraoperative image guidance has offered a less invasive and more precise approach to the medial and inferior orbit, without crossing the optic nerve. During the past few years, transnasal endoscopic approach have become well established for orbital decompression, orbital medial wall fracture repair, optic canal decompression, and removal of orbital roof lesions. Bleeding from the nasal mucosa, a main concern of the oculoplastic surgeon, is minimal if the nose is prepped with vasoconstrictors. Recent publications show that this approach allows the drainage of a subperiosteal orbital abscess without an external incision. It is also is a preferable one for infero-medial apical lesions due to the lack of neurovascular retraction. Transnasal approach to the orbital apex incudes middle antrostomy followed by a complete ethmoidectomy and optional sphenoidotomy. Lamina papyracea is removed posteriorly to the level of anterior ethmoidal artery and medially to the infraorbital nerve. Next, periorbit is opened. Cautery and trimming of orbital fat is done, and inferior and medial rectus muscles are were dissected and retracted apart. Additional tool can be introduced through the contralateral nostril using temporary cut in the nasal septum. (Fig. 46.14

Fig. 46.14
figure 14

Endoscopic view of transnasal approach for removal of medial orbital apex cavernous hemangioma. P – incised and retracted periorbit; OF – orbital fat; MRM – medial rectus muscle; IRM – inferior rectus muscle; asterix – hemangioma (Courtesy of Dr. Arkadi Yakirevitch)

Full size image

) It allows for bimanual intra orbital manipulation.

The use of a transmaxillary endoscopic approach has also been described for repair of orbital floor fractures.

The primary advantages of the use of the endoscope in the context of orbital surgery are safe visualization in the narrow orbit which may otherwise require bone removal for adequate exposure, excellent depth illumination, magnification, the potential for supervision of trainees, and the ability to engage observers into the operating field.

Complications of endoscopic surgery include uncontrolled bleeding, vision worsening, enophthalmos, hypoglobus and diplopia. Injury to orbital structures and dura with the instrumentation can be avoided by ensuring good visualization at all times and resting the instrument against a firm surface for stabilization.

Neurosurgical Approach

Neurosurgical approaches to the orbit are utilized during combined surgery with the neurosurgeon and the orbital surgeon. The approach is useful for intracranial lesions that invade into orbit or the optic canal or for deep-infiltrating posterior orbital lesions for which wide exposure is desired. The transcranial neurosurgical approach to the orbit as well as orbital rim reconstruction is discussed in a chapter dedicated to this topic.

Intraoperative Complications

Achieving meticulous hemostasis is vital for successful orbital surgery. Intraoperative bleeding impairs visualization and prolongs operative time. The risk of postoperative hemorrhage with visual loss dictates complete hemostasis before closing the orbital cavity. Pressure packing with gradual removal and hemostasis of oozing vessels can usually be sufficient for soft tissue hemorrhage. Cautery, bone wax, and chemical coagulators are usually sufficient to stop all significant bone bleeding. The anesthesiologist should slowly raise the blood pressure to baseline levels after tumor removal to ensure that no bleeders are missed. Deep extubation should be performed to avoid excessive Valsalva pressure. Nerve laceration or contusion can occur during surgery. It can take as long as 4 weeks for new axons to regenerate across an anastomosis. The patient and the surgeon should wait patiently for recovery of nerve function. Dural penetration with cerebral spinal fluid (CSF) leak should be visualized and managed intraoperatively. Dura mater can be exposed without a tear, and the surgeon needs to carefully observe that it is not lacerated. With good visualization, the surgeon can suture the dura with a silk suture on an atraumatic vascular tapered needle. If overlooked or poorly controlled, a CSF leak can cause postoperative rhinorrhea. Nasolacrimal sac or duct injuries can occur when operating in the area of the medial canthus. The sac is less vulnerable than the canalicular system. If there is any doubt of canalicular laceration, the surgeon should intubate the canaliculi to ensure patency.

Postoperative Complications

Emergent Complications

The most feared complication of orbital surgery is vision loss. Visual loss may result from intraoperative manipulation or postoperative hemorrhage. Perioperative visual loss can occur from direct manipulation of the optic nerve such as seen with surgery on optic nerve sheath meningiomas. Overzealous traction or “blind” dissection of tumors attached to the optic nerve can also produce irreversible posterior optic nerve ischemia. Even moderate traction on an optic nerve for longer than 2 min should be avoided, especially when hypotensive anesthesia is being used. The posterior ciliary arteries also can be damaged when peeling intraconal tumors off the posterior globe. The key to avoiding these complications is meticulous dissection, strict adherence to the knowledge of anatomic landmarks, and good visualization. The use of cautery near the optic nerve should be avoided as much as possible. In the postoperative stage, caution should be made to avoid bleeding or excessive edema that can cause a rise in intraorbital pressure, leading to a posterior ischemic optic neuropathy. This occurs most frequently in elderly patients, who are more susceptible to ischemic optic neuropathy. Since the ischemic event occurs posterior to the cribriform lamina, the optic nerve and retina usually will appear normal despite the visual loss. Retinal artery occlusion and anterior ischemic optic neuropathy can also occur from direct manipulation of the retinal artery or the posterior ciliary arteries.

Tight pressure dressings over the eye are to be avoided due to the threat of causing a “compartment syndrome” of the orbit. A sealed dressing can also delay the finding of acute visual loss in the postoperative state. Infections are not common after orbital surgery. The orbit is well vascularized, and even if the surgery involves the nasal sinuses, infection is rare. During the operation, the anesthesiologist usually infuses a single antibiotic dose, and during the postoperative state, the patient is given a course of oral antibiotics. Infection should be promptly controlled, and signs of possible meningitis should be assessed and addressed urgently.

Non-emergent Complications

Excessive hemorrhage and edema during surgery or in the postoperative state can lead to conjunctival prolapse with conjunctival desiccation. Ophthalmic ointment is applied liberally until the swelling subsides.

Diplopia can be caused by excessive traction on any extraocular muscle (myogenic), damage to a cranial nerve (paresis), or iatrogenic injury to extraocular muscles, leading to scarring (restriction). In most cases, symptomatic diplopia resolves without sequelae.

Ptosis can be seen after orbital surgery, but it generally resolves. Biopsy of superior lesions can cause bleeding into the levator muscle or aponeurosis, resulting in ptosis. Damage to the superior division of the cranial nerve III and hemorrhage in the orbital apex can also cause ptosis. These patients can be observed for up to a year since this condition tends to resolve with time.

Wound dehiscence without any tension can be carefully observed, but resuturing will give the best outcome to any dehisced tissue. Patients with vascular pathology, diabetics, and smokers should be watched carefully to ensure wound closure.

Disturbance of the ciliary ganglion after dissection lateral to the optic nerve, or posterior to the inferior oblique muscle, can result in damage to the pupillary fibers and subsequent irregularity of the pupil.

Total removal of the lacrimal gland for benign, pleomorphic lacrimal gland tumors can cause xerophthalmia in many patients.