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Chapter 96 – Orbital Surgery

Chapter 96 – Orbital Surgery

 

JONATHAN J. DUTTON

 

 

 

 

 

DEFINITION

• Orbital surgery involves tissues bounded by the bony orbital walls posteriorly and by the orbital septum anteriorly.

 

KEY FEATURES

• Surgical approaches to the orbit may be anterior, lateral, medial, or superior, depending on the location of the lesion and the exposure needed.

• Meticulous attention to anatomical detail, hemostasis, and gentle manipulation of tissues is mandatory to avoid devastating complications.

• The most important complications are loss of vision, injury to extraocular muscles with diplopia, hemorrhage, and cerebrospinal fluid leak and possible meningitis.

 

 

 

INTRODUCTION

Orbital and lacrimal gland surgery is indicated for the evaluation or treatment of orbital disease, restoration of anatomical relationships following trauma, or cosmetic improvement of congenital or acquired deformities. Biopsy of mass lesions is an important technique. Although some authors advocate fine-needle aspiration biopsy of orbital mass lesions under computed tomographic or echographic guidance, [1] [2] [3] cytological evaluation on such specimens may be inaccurate.[4] For most orbital lesions, an open biopsy is preferred.

The removal of orbital masses may be indicated when these are well defined and cause either functional compromise or cosmetic deformity. Benign tumors, such as hemangiomas, schwannomas, dermoid cysts, and mixed lacrimal gland tumors, and some malignant lesions usually can be dissected away from adjacent structures. More infiltrative lesions, such as lymphangiomas, usually are impossible to extirpate completely. When not amenable to medical therapy and when it is necessary to restore function, these tumors may be carefully debulked.

Orbital abscesses, either following surgical or nonsurgical trauma or associated with sinusitis, may require direct drainage and antibiotic therapy. When they are loculated within the orbit, drainage to the surface is appropriate.

Nonsurgical traumatic injury to the orbit frequently involves bony fracture or hemorrhage. Orbital rim fractures are easily accessible through anterior approaches; they may be repaired with miniplate fixation of the displaced fragments. Orbital wall fractures, often associated with soft tissue injury or incarceration, must be carefully explored and realigned when it is necessary to restore function or orbital volume. The exact surgical approach depends on the nature and location of the fractures.

Diffuse orbital hemorrhage following trauma may produce massive proptosis and, occasionally, increased intraocular pressure or optic nerve compression. Orbital decompression with a lateral canthotomy is usually sufficient to manage the potential visual loss. If this fails, drainage of loculated pockets or bony decompression may be necessary. Progressive loss of vision associated with proptosis and downward displacement of the globe suggests a subperiosteal hematoma. The diagnosis is confirmed using orbital echography or computed tomography (CT), and immediate drainage via an anteromedial orbitotomy usually reverses the visual loss.

Massive proptosis associated with Graves’ orbitopathy may require orbital decompression for the treatment of threatened visual function or cosmetic disfigurement. This is achieved by removal of the inferior or medial orbital walls or, more commonly, both. Decompression also may be indicated for other expanding lesions of the orbit that cannot be surgically extirpated.

Removal of the globe and part or all of the normal orbital contents may be necessary to manage neoplastic processes or to control chronic pain. It is also useful for the cosmetic improvement of congenital or traumatic ocular or orbital deformities. When only the globe is involved, enucleation or evisceration is indicated (see Chapter 97 ). Cure of neoplasms that extend into the orbit from the globe or eyelids may require more radical exenteration of all the orbital soft tissues.

HISTORICAL REVIEW

The history of orbital and lacrimal gland surgery predates the Christian era—references can be found in writings from antiquity. In 1583, Bartish provided one of the earliest complete descriptions of an orbital procedure (exenteration) for the eradication of orbital disease.[5] The evolution of more modern surgical techniques has paralleled both the accumulation of anatomical knowledge since the middle of the nineteenth century and the development of more sophisticated surgical instruments. Surgical loupes and the operating microscope, fiberoptic illumination, and better methods of hemostatic control have each contributed to safer and more effective procedures. Of particular importance has been the introduction of modern imaging techniques, including CT, magnetic resonance imaging, and orbital echography, which have permitted more precise diagnosis and better surgical planning.

PREOPERATIVE EVALUATION AND DIAGNOSTIC APPROACH

Before a decision is made about the need for orbital or lacrimal gland surgery, a complete evaluation of the patient is mandatory.[6] A careful medical and ophthalmic history uncovers any possible local and systemic diseases that may contribute to the presenting orbital symptoms.

Measurement of visual acuity and current refraction is mandatory. A visual field test is required on all patients who have suspected orbital disease, especially if visual loss occurs.

 

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The presence of periorbital edema or erythema, chemosis, ptosis, and decreased corneal or facial sensation is noted. The degree of proptosis, if any, and the direction of globe displacement are important to help localize orbital pathology. Ocular motility should be carefully measured and, if abnormal, a forced traction test performed to distinguish between paralytic and restrictive causes. The anterior orbit should be palpated for any abnormal masses behind the bony rim.

Modern orbital imaging techniques provide critical information on the specific location of lesions, as well as their relationship to adjacent structures (see Chapter 84 ). Echography allows the determination not only of topographical contours and surface characteristics but also of the consistency, gross internal structure, and vascularity, which may be difficult to detect with other techniques.[7] [8] High-resolution orbital CT with contrast provides superb topographical data and structural details that often can pinpoint the diagnosis without further work-up; it is essential if there is any suggestion of bony involvement.[9] Orbital CT should be obtained in both axial and coronal orientations, with contrast enhancement and bone windows when indicated. Key information, not available with CT alone, may be provided by magnetic resonance imaging, particularly with surface coil technology and fat suppression techniques.

GENERAL TECHNIQUES

General techniques in orbital and lacrimal gland surgery require a thorough understanding of orbital anatomy and the relationships with paraorbital structures. More than for other ophthalmic procedures, orbital and lacrimal gland surgery demands strict respect for fascial planes, adequate exposure and visualization, a planned approach appropriate to the expected pathology, and concern for postoperative cosmesis. The surgeon must be well versed in both gross and microsurgical techniques and must not hesitate to involve other surgical subspecialists when appropriate. Gentle dissection is essential to avoid injury to delicate neurovascular structures; meticulous hemostasis is critical to prevent complications and even potential blindness.

The orbit may be approached through several surgical routes, all generally grouped under the term orbitotomy—literally, to cut into the orbit ( Box 96-1 ). Since this term has no particular reference to bone, it may be applied to anterior incisions through the eyelid and lateral or other approaches through the orbital walls. Since the orbital septum represents the anatomically anteriormost layer of the orbital fascial system, any transeyelid surgery that is carried through the septum represents orbital surgery. The major approaches to the orbit are:

• Anterior transcutaneous orbitotomy;

• Lateral orbitotomy; and

• Superior orbitotomy.

The specific approach taken for each orbital procedure is determined primarily by:

• The nature of the pathology;

• The ultimate goals of surgery—whether diagnostic biopsy, palliative debulking, or complete excision;

• The location and size of the lesion; and

• The age or general medical condition of the patient.

For biopsy alone, a palpable anterior lesion usually can be reached through a small transcutaneous or transconjunctival incision. Removal of such a lesion, however, may require a much broader exposure, which may necessitate removal of the lateral orbital wall. Posterior or apical lesions, even when small, usually can be safely reached only via a craniotomy approach. Medial lesions are best approached from the medial side so as not to risk injury to the optic nerve and muscle cone by instruments passed through a lateral orbitotomy incision. The approach to malignant tumors must be carefully planned to avoid contaminating adjacent tissue fields. The biopsy site must be placed so as not to transcend uninvolved closed compartments and must be located within the zone of subsequent excision. When complete excision

 

 

Orbital Surgery: General Techniques

 

ANTERIOR ORBIT

Anterior orbitotomy

 

Inferior orbitotomy

 

 

MID-ORBIT

Lateral orbitotomy

 

Medial orbitotomy

 

 

ORBITAL APEX

Superior orbitotomy-craniotomy

 

 

 

 

is required, the surgeon must be prepared to remove a wide section of normal tissue, including adjacent bone.

SPECIFIC TECHNIQUES

The orbitotomy procedures include a number of operations for access into the various orbital soft tissue compartments. The specific approach selected depends on the following[10] [11] :

• The working diagnosis;

• The location of the pathology;

• Involvement of adjacent bone or paraorbital areas;

• The need for wide surgical margins; and

• The requirements for adequate exposure.

Three surgical spaces are of interest to the orbital surgeon, each of which requires specific consideration for appropriate visualization.[12] The subperiosteal compartment lies between the orbital bony walls and periorbita. Access to this space is necessary to repair orbital wall fractures or to decompress expanding orbital volume, as in Graves’ orbitopathy. This is the location where subperiosteal hematomas, expanding mucoceles, and some intracranial lesions, such as sphenoid wing meningiomas, occur. Also, bone lesions, such as aneurysmal bone cysts, cholesteatomas, and eosinophilic granulomas, frequently are confined to the subperiosteal space.

The extraconal or peripheral orbital space lies between the periorbita and the fascial septa that interconnect the extraocular muscles. This septal system is far more complex than once believed[13] [14] ; it is unusual for lesions to be confined precisely to the extraconal space alone. Access to the peripheral space may be through a transcutaneous trans-septal orbitotomy, if in the anterior orbit, or through a lateral or transconjunctival medial orbitotomy, if deeper.

The intraconal or central orbital space is delimited by the extraocular muscle cone from the annulus of Zinn to the posterior Tenon’s capsule. It is not a clearly defined compartment, however, since the intermuscular septum is largely incomplete posteriorly and poorly defined anteriorly. Lesions frequently extend between the extraconal and intraconal compartments without regard to these artificial boundaries. [6] Optic nerve gliomas and sheath meningiomas are located primarily within the muscle cone. The surgical approach is via a lateral orbitotomy for deep lesions and via a transconjunctival medial or lateral orbitotomy for lesions immediately behind the globe. Other types of approaches have been introduced for access to the orbital apex and posterior orbit.[15] [16]

The specific surgical procedures described here are designed to give direct access to certain structures and to minimize trauma to adjacent tissues. The anterior orbitotomies are used to reach lesions in the anterior orbit to the level of the posterior globe. The transconjunctival route allows entrance directly into the extraconal space anywhere around the perimeter of the eye. With removal of an extraocular muscle and opening of Tenon’s capsule, the intraconal compartment immediately behind the globe also becomes available.

Lateral orbitotomy involves removal of the lateral orbital rim and various amounts of the greater sphenoid wing. It allows

 

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Figure 96-1 Anterior orbitotomy approach, upper eyelid. A lid crease incision is cut, and the orbital septum is opened. Fat is then retracted, and the lesion is identified for biopsy or removal. The anterior view is the inverted image as seen by the surgeon. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

wide access to the deep orbital contents and optic nerve; it is preferred for most retrobulbar lesions. Extension of the superior bony cut gives better exposure to the lacrimal gland for en bloc excision within its fossa. The lateral orbitotomy may be combined with other approaches, for example, the medial orbitotomy, for better visualization of the deep medial wall.

Meticulous attention to hemostasis must be ensured throughout for visualization. After adequate exposure has been achieved, the dissection must proceed slowly and with great deliberation. Magnification and microdissection instruments are used to gently separate the lesion from adjacent normal structures. Light traction on the lesion usually is necessary to allow posterior dissection. This may be achieved with forceps, but for more vascular lesions, a cryoprobe allows traction without surface bleeding. Dissection around the optic nerve is particularly hazardous because of the delicate pial vessels that penetrate its surface and the close approximation of the posterior ciliary nerves.

Transcutaneous Anterior Orbitotomy

Transcutaneous anterior orbitotomy is used to access the anterior extraconal orbital space (see Chapter 83 ) to biopsy or excise small lesions located beneath the orbital rims. [17] With care and the use of retractors, deeper lesions to the level of the posterior globe are accessible.

An incision line is marked in the upper eyelid crease to access the superior orbit, or 2?mm below the lower eyelid lash line to access the inferior orbit. The skin and orbicularis muscle are opened with scissors to enter the postorbicular fascial plane. A horizontal cut is made with a scalpel or scissors through the orbital septum to enter the extraconal orbital space. If the lesion is not visible immediately, careful palpation through the wound usually locates the structure.

The fat lobules are gently separated with narrow malleable retractors and a Freer periosteal elevator, taking care not to injure vascular structures ( Fig. 96-1 ). In the upper eyelid, the levator muscle lies toward the superior side of the wound. In the lower eyelid, the inferior oblique and rectus muscles lie on the inferior side of the wound.

The lesion then may be biopsied or dissected carefully away from adherent tissues. All bleeding points are cauterized meticulously with bipolar electrode forceps; care is taken to avoid excessive traction on the orbital fat. The cutaneous wound is closed with a running suture of 6–0 nylon or silk or with interrupted stitches of 7–0 Vicryl or chromic gut.

 

 

Figure 96-2 Transconjunctival medial orbitotomy approach. The conjunctiva is opened just anterior to the muscle insertion, and Tenon’s capsule is separated from the sclera. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

Transconjunctival Anterior Orbitotomy

The transconjunctival approach to the anterior orbit is useful for lesions close to the globe, for that portion of the optic nerve immediately posterior to the globe, and for most anteriorly situated intraconal lesions. It also avoids skin incisions that may be cosmetically objectionable in some patients.

An incision is made through conjunctiva and anterior Tenon’s capsule, and the dissection is carried in the episcleral space to the posterior globe ( Fig. 96-2 ). Disinsertion of one rectus muscle will facilitate deeper dissection ( Fig. 96-3 ). The location of the incision depends on the location of the orbital lesion. Posterior Tenon’s is opened to access the retrobulbar compartment. Malleable retractors and rotation of the globe will provide adequate visualization. In small orbits, however, working room and visualization may be very limited.

 

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Figure 96-3 Transconjunctival medial orbitotomy approach. The globe is rotated, and malleable retractors are used to visualize the posterior Tenon’s capsule. Opening of this layer gives access to the retrobulbar space. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

Lateral Orbitotomy

The lateral approach is used for deeper orbital lesions that cannot be reached through an anterior incision or that require wider exposure for excision. This gives excellent access to the midintraconal compartment, except for the extreme medial side.

A variety of skin incisions can be used, including an S-shaped rim incision, a horizontal canthal crease incision, or an eyelid crease incision. [18] The skin is cut with a scalpel blade, and the dissection is extended through orbicularis muscle and deep fascia to the periosteum of the orbital rim. Periosteum along the lateral orbital rim is cut and elevated from the lateral orbital wall for a distance of 3–4?cm ( Fig. 96-4 ). Similarly, periosteum is elevated from the temporal fossa to expose the zygomatic bone and greater wing of the sphenoid (see Chapter 83 ). Wide, malleable retractors are inserted on either side of the bony orbital rim at the level of the frontozygomatic suture line to protect the soft tissues. The bone is cut with an oscillating saw, angling the cut slightly inferiorly and parallel to the orbital roof. The cut is made about 1?cm deep, into the thin bone along the sphenozygomatic suture line. A second cut is made through the orbital rim just above the zygomatic arch ( Fig. 96-5 ). Small holes can be drilled on either side of each cut near the rim to facilitate later replacement of the bone. The bony rim is grasped with a sturdy rongeur between the cuts and fractured outward. The thin bone of the greater sphenoid wing is removed with rongeurs to provide adequate retrobulbar exposure ( Fig. 96-6 ). The lateral rectus muscle is identified by grasping its insertion at the globe and rotating the eye medially. The periorbita is then opened with scissors by making a vertical cut just inferior or superior to the muscle.

The orbital fat is dissected gently by blunt separation of the interlobular capsules with a Freer elevator or dissectors. Once the lesion has been identified, it is dissected carefully from adjacent structures, with meticulous hemostasis maintained with gentle cautery or application of neuropathies moistened with epinephrine or thrombin. Traction on the lesion may be achieved with the use of a cryoprobe ( Fig. 96-7 ). After biopsy or removal of the lesion, the periorbita is closed with interrupted sutures of 6–0 Vicryl, with several gaps left in the closure for drainage. The lateral orbital rim is replaced and secured with

 

 

Figure 96-4 Lateral orbitotomy approach. The lateral orbital rim is exposed, and the periorbita is elevated from the lateral orbital wall. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

 

 

Figure 96-5 Lateral orbitotomy approach. After periosteum has been elevated from the temporal fossa, the lateral rim is cut. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

microplate fixation or with 4–0 Prolene or nylon sutures passed through the predrilled holes. Periosteum is closed over the orbital rim with interrupted stitches of 4–0 Vicryl. The orbicularis muscle is approximated with 6–0 chromic gut and the skin with 6–0 nylon or silk vertical mattress sutures.

A firm, but not tight, dressing is placed over the orbit for 24 hours. Systemic corticosteroids may be administered for several days, especially if any manipulation around the optic nerve was carried out. Antibiotic ointment is applied to the suture line four times daily for 1 week. The skin sutures are removed after 5–7 days.

 

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Figure 96-6 Lateral orbitotomy approach. The greater sphenoid wing is removed to provide adequate exposure of the deep orbit. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

Orbital Decompression: Inferior and Medial Walls

Orbital decompression is indicated to expand the bony walls when increased orbital soft tissue volume is present. The procedure is used most frequently for Graves’ orbitopathy associated with optic nerve compression or severe exophthalmos and lagophthalmos. [19] [20] [21] [22] The operation involves intentional outfracturing of selected orbital walls, usually into adjacent paranasal sinuses ( Fig. 96-8 ). Although some surgeons use the transantral approach,[23] either alone or in combination with an orbital incision, most prefer the transorbital route via an anterior transperiosteal inferior orbitotomy incision with removal of the orbital floor and ethmoid labyrinth.[20]

In all operations for decompression, the periorbita must be opened widely to allow fat lobules to prolapse into the bony defects ( Fig. 96-8 ). Without this step, surgery is ineffective. In Graves’ orbitopathy, fibrosis of the interlobular fascial septa may prevent prolapse. Careful blunt dissection to separate these is needed, but in some cases, the effect of decompression is still disappointing.

The operation may be performed through a subciliary incision cut 2?mm below the lower eyelid lash line or through a transconjunctival fornix incision. Periosteum is incised 2?mm outside the orbital rim and dissected over the latter with a Freer elevator. Elevation of periorbita is continued along the orbital floor for a distance of 3.5–4?cm posterior to the rim ( Fig. 96-9 ). The thinnest part of the floor is located medial to the infraorbital canal; a small hole is punched through this area with a hemostat. The orbital floor medial to the infraorbital canal is removed with rongeurs ( Fig. 96-10 ). Additional bone is removed back to the posterior wall of the maxillary sinus, medially to the maxillary-ethmoid suture, and laterally to the edge of the infraorbital tissue. The author prefers to leave a narrow bridge of bone over the infraorbital nerve to prevent postoperative injury from displaced orbital contents.

The periorbita is sutured to periosteum over the inferior orbital rim with interrupted sutures of 4–0 Vicryl. Skin and conjunctiva are closed with a running suture.

A firm dressing is applied for 24 hours. Antibiotic ointment is placed on the suture line four times daily for 7 days. Systemic antibiotics and nasal decongestants are prescribed for 1 week. The skin sutures are removed after 5–7 days.

 

 

Figure 96-7 Lateral orbitotomy approach. The periorbita is opened, and the lesion is located using gentle dissection. A cryoprobe facilitates removal without surface bleeding. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

Repair of Orbital Floor Fractures

Blowout fractures of the orbital floor result from hydraulic compression of orbital contents[24] and perhaps from deformation forces transmitted directly from the orbital rims. These occur most frequently just medial to the infraorbital canal, where the bone is thinnest. [25] [26] Paresthesias of the cheek and upper gum suggest a more central fracture with injury to the infraorbital nerve. Spontaneous recovery of sensation usually occurs after several months. Vertical diplopia and a positive forced traction test suggest mechanical restriction, with entrapment of the inferior rectus muscle or, more likely, of its fascial attachments in the inferior orbit.[27] However, vertical diplopia and a positive forced traction test also may be seen with contusion injuries to the muscle,[28] in which case motility function typically improves over several weeks as the hematoma resolves.[29] [30] Failure to improve over several weeks suggests mechanical restriction that requires surgical exploration.

Early enophthalmos is caused by outward displacement of the orbital contour with an increase in volume of the orbital cavity. It may be associated with downward displacement of the globe when the fracture site involves primarily the orbital floor. Enophthalmos or hypo-ophthalmos alone usually does not cause diplopia, but it may be of cosmetic consequence. When significant, this is an indication for early surgical intervention.[31] [32] Associated orbital hemorrhage initially can mask enophthalmos, which may become manifest only after several weeks, when the hematoma resolves. Late enophthalmos, which may occur over several years or even over several decades, results from progressive fat atrophy. This is repaired using volume augmentation of the orbital contents.

Medial wall fractures are often associated with those of the orbital floor and most often result in orbital emphysema. Medial rectus muscle entrapment is uncommon, but it may produce a horizontal diplopia. Enophthalmos may be significant even with pure ethmoid fractures. Injury to the lacrimal drainage system may be seen with more anterior medial rim or nasomaxillary fractures.

Before contemplating any surgical intervention, radiographic imaging is essential. In most cases, CT in both the axial and coronal planes and with bone window settings helps determine which

 

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Figure 96-8 Orbital decompression. The orbital floor and medial wall are removed. The periorbita is then opened to allow fat to prolapse into the adjacent sinuses. The anterior view is the inverted image as seen by the surgeon. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

 

 

Figure 96-9 Orbital decompression. A skin or conjunctival incision is used to expose the inferior orbital rim. The periorbita is elevated to expose the orbital floor. The anterior view is the inverted image as seen by the surgeon. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

 

 

Figure 96-10 Orbital decompression. The floor is removed using rongeurs. The maxillary sinus is then exposed. The anterior view is the inverted image as seen by the surgeon. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

 

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Figure 96-11 Orbital floor fracture repair. The floor is exposed as for orbital decompression. The fracture site is identified, and any soft tissue incarceration is freed. The anterior view is the inverted image as seen by the surgeon. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

 

 

Figure 96-12 Orbital floor fracture repair. A suitable floor implant is placed over the defect and fixed in position. The anterior view is the inverted image as seen by the surgeon. (Adapted with permission from Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.)

cases require immediate repair and which are likely to improve using medical management alone.[33] [34] In many cases, orbital surgery can be avoided, with no compromise of long-term results. [35] [36]

For the repair of orbital floor fractures, the operation is similar to that for orbital decompression described earlier, up to the stage of exposure of the floor (see Fig. 96-9 ). The anterior edge of the fracture site is then exposed, and the extent of incarceration of the periorbita and fascial tissues is evaluated ( Fig. 96-11 ). Bony fragments are gently depressed or elevated while periorbita and fat lobules are teased free with a periosteal elevator or microdissector. Orbital tissues are carefully separated from the infraorbital nerve and vessels. The entire fracture site must be exposed to its posterior limit.

A piece of Supramyd, Teflon, or other implant material is cut to a size large enough to overlap the defect by at least 5?mm on all sides. It is best to fix the implant into position to prevent later migration.[37] If a full floor implant is used, one or two small holes are drilled through the orbital rim and through the front of the implant, and the latter is secured into position with 4–0 Prolene sutures to prevent forward displacement ( Fig. 96-12 ). If a smaller implant is used, a small tongue flap can be cut and pushed beneath the anterior defect edge to prevent migration. Periosteum is closed over the orbital rim with interrupted sutures of 4–0 Vicryl. The skin or conjunctival wound is repaired with a running stitch.

COMPLICATIONS

Orbital and lacrimal gland surgery is fraught with potential complications, even for experienced surgeons. The close approximation of numerous neurovascular structures means that complications may lead to disastrous consequences for visual function. With a comprehensive knowledge of anatomy, intense attention to surgical detail, and strict respect for tissue handling, these risks can be kept to a minimum.

Visual loss is the most serious complication of orbital surgery. It may result from the following:

• Optic nerve injury by retractors;

• Excessive pressure on the globe;

• Cautery adjacent to the optic nerve; or

• Vascular compromise.

The surgeon must keep in mind the anatomical relationships in the orbital apex and the position of key landmarks. Constant monitoring of pupillary reactions during surgery is important.

 

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Postoperative orbital hemorrhage is a rare complication that largely can be avoided by meticulous attention to hemostasis during surgery. Excessive traction on orbital fat should be avoided, and bone wax must be applied to any vessels retracted into bony canals. An expanding postoperative hematoma is heralded by progressive proptosis, deep orbital pain, and decreasing vision. The combination of CT and echography helps localize the blood pocket. Treatment may require immediate surgical decompression, either through the original surgical wound or through an alternative, more direct route to the hematoma.

A cerebrospinal fluid (CSF) leak may occur with any surgery on the anterior medial orbital wall carried above the level of the frontoethmoid suture line and causing injury to the cribriform plate. If minimal, it may be treated conservatively, as for CSF rhinorrhea. Alternatively, the leakage site may be packed with fat or sealed with cyanoacrylate glue, and a lumbar drain may be placed. The patient should be provided with appropriate antibiotics.

Diplopia is a constant risk with any surgery adjacent to extraocular muscles or their motor nerves. Muscle sheaths should be left intact whenever possible, and traction sutures across the muscle bellies must be avoided. The inferior oblique muscle is particularly vulnerable where it lies immediately behind the orbital septum, just inside the inferior orbital rim. It may not be recognized by an inattentive orbital surgeon. In the superior medial orbit, the superior oblique trochlea is injured easily by overly aggressive periorbital dissection. When extraocular muscle dysfunction fails to resolve over 3–4 months, strabismus surgery may be required.

Upper eyelid ptosis occurs almost universally following most surgery on the orbit. In most cases, this is transient and usually resolves over days to weeks. Permanent ptosis may result from injury to the aponeurosis, Whitnall’s ligament, or the superior division of the oculomotor nerve. If the ptosis does not resolve within 3–4 months, surgical repair may be necessary.

Lower eyelid ectropion, epiblepharon, and other eyelid malpositions may result from injury to the capsulopalpebral fascia or scarring of the orbital septum. These disorders are rarely seen in younger individuals but are more common in older patients who have preexisting eyelid laxity. The appropriate dissection planes should be maintained in all dissections carried through these structures, similar to the techniques applied in eyelid surgery.

OUTCOME

With appropriate planning and surgical technique, orbital surgery yields a high degree of success and few permanent complications. Visual function usually is improved, cosmetic appearance is enhanced, and life-threatening conditions can be eliminated. In some cases, however, vision or cosmesis must be compromised in favor of preservation of life. Such decisions should always be made with the complete understanding and participation of the patient. Occasionally, less radical surgery may be undertaken, even in the face of serious pathology, as dictated by the patient’s age, physical condition, and visual status of the contralateral eye.

 

 

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2. Dresner SC, Kennerdell JS, Dekker A. Fine needle aspiration biopsy of metastatic tumors. Surv Ophthalmol. 1983;27:397–8.

 

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7. Byrne SF. Standardized echography in the differentiation of orbital lesions. Surv Ophthalmol. 1984;29:226–8.

 

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12. Dutton JJ. Atlas of clinical and surgical anatomy. Philadelphia: WB Saunders; 1994.

 

13. Koornneef L. Details of the orbital connective tissue system in the adult. Acta Morphol Neerl Scand. 1977;15:1–34.

 

14. Koornneef L. Orbital septa: anatomy and function. Ophthalmology. 1979; 86:876–80.

 

15. Goldberg RA, Shorr N, Arnold AC, Garcia GH. Deep transorbital approach to the apex and cavernous sinus. Ophthal Plast Reconstr Surg. 1998;14:336–41.

 

16. Kennerdell JS, Maroon JC, Celin SF. The posterior inferior orbitotomy. Ophthal Plast Reconstr Surg. 1998;14:277–80.

 

17. Dutton JJ. Atlas of ophthalmic surgery, vol II. Oculoplastic, lacrimal, and orbital surgery. St Louis: Mosby–Year Book; 1991.

 

18. Harris GJ, Logani SC. Eyelid crease incision for lateral orbitotomy. Ophthal Plast Reconstr Surg. 1999;15:9–16.

 

19. Linberg JV, Anderson RL. Transorbital decompression: indications and results. Arch Ophthalmol. 1981;99:113–9.

 

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