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Visit Expert Consult ( expertconsult.inkling.com ) for videos on topics discussed throughout the text.
Introduction
Orbital tumors are rare. Biopsy for removal or diagnosis is often necessary. From our discussion in the last chapter, you have a good idea about which tumors should be removed (excisional biopsy) and which tumors should be sampled (incisional biopsy). This chapter describes the logic for choosing the most appropriate surgical approach for anterior and deep orbital masses. Understanding the surgical spaces of the orbit helps you with an anatomic approach that can guide your choice of procedure as well as help you navigate in the orbit itself. Many tumors can be approached from the front of the orbit through an anterior orbitotomy. Tumors deeper in the orbit require more advanced procedures.
Before orbitotomy, you must prepare the patient, operating team, and operating room. A preoperative medical workup and review of medications, especially those with anticoagulative effects, are necessary. The surgical plan should be coordinated with any additional surgical teams and the pathologist. Once in the operating room, the procedure should be reviewed with the scrub team, and the equipment and instruments need to be organized. Some of the specialized equipment, instruments, and surgical techniques used in orbital surgery are reviewed. Proper illumination, magnification, exposure, orbital dissection, and hemostasis are necessary for a successful outcome to the orbitotomy.
Because many of the orbital processes that you see occur in the anterior orbit, you should be most familiar with the anterior orbitotomy approaches. Learn to do the following three of these:
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The upper lid skin crease approach
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The lower lid transcutaneous approach
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The lower lid transconjunctival approach
Because you are likely to be doing these procedures, I describe them in detail.
Deep tumors in the orbit are more difficult to expose. Deeper tumors in the medial aspect of the orbit are especially difficult to reach. Specialized anterior orbitotomy techniques can be used to approach deeper tumors; however, you may not want to perform them until you master the more basic procedures. Because these procedures are used less often, I have included less detail for you. Nevertheless, you should know that they exist.
Deep lateral and apical orbital tumors may require removal of one or more walls of the orbit. These procedures include
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The lateral orbitotomy
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The transcranial orbitotomy
Deep tumors lateral to the optic nerve are usually approached using the lateral orbitotomy with bone removal. This is the classic orbitotomy, or workhorse, for deeper orbital tumors, so I describe this technique in detail, as well.
Tumors in the orbital apex must be approached using the transcranial orbitotomy. This approach requires elevation of the brain and removal of the orbital roof. The transcranial orbitotomy can be combined with other intracranial approaches to the optic canal, chiasm, and sphenoid wing. The procedure requires coordination between the ophthalmology and neurosurgery teams. You should understand the indications for this procedure. If you have the opportunity to assist with a transcranial orbitotomy, you will see some incredible orbital anatomy.
Approach to the Patient with Proptosis
In the last chapter, we discussed the evaluation of the patient with proptosis. The diagnosis begins with a history and physical examination utilizing the P’ s of the orbital examination. Most patients with proptosis undergo a computed tomography (CT) scan as the primary diagnostic imaging test. A magnetic resonance imaging (MRI) scan is used as a secondary test and is especially useful for evaluating the orbitocranial junction. Some cases require both CT and MRI. Using the information obtained from the history, physical examination, and imaging tests, you can arrive at a differential diagnosis. In a few patients, the exact cause of the proptosis is evident (e.g., thyroid orbitopathy). In other patients, the differential diagnosis is based on the tissue involved (e.g., optic nerve tumor). In the remaining patients, one can only arrive at a pathogenic diagnosis (e.g., inflammation or neoplasm). In a small number of patients, you can initiate medical treatment without further testing (e.g., antibiotic treatment for orbital cellulitis). Most patients require a biopsy.
The orbital biopsy is either incisional or excisional. As a general rule, infiltrative processes suggest malignancy and require an incisional biopsy. The exact nature of a malignancy or benign infiltrative disorder is identified based on the incisional biopsy. Usually, additional medical or surgical therapy is required. Well-circumscribed or cystic masses tend to be benign and amenable to complete removal or excisional biopsy. The ovoid mass of a benign mixed tumor of the lacrimal gland is an example of a well-circumscribed benign tumor for which an excisional biopsy is indicated (a tumor rarely seen clinically, but commonly seen in questions on board examinations). Incomplete removal may allow eventual recurrence of a malignant form of lacrimal tumor. There are exceptions to these rules, the most common being the well-circumscribed mass that is diagnosed histopathologically as a malignant lymphoid process. Incisional rather than excisional biopsy should be used for lymphoid tumors, even though they are well circumscribed. The malignant and benign forms of lymphoid infiltrate cannot be distinguished clinically. Neither form is treated with excision; both are treated with either radiation therapy or medication.
Choosing the Surgical Approach
There are several factors to consider in choosing the surgical approach:
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Anterior or deep location
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Position relative to the optic nerve
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Surgical space occupied
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Goal of biopsy
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Incisional
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Excisional
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Based on these factors, the safest and most practical approach to reaching the orbital tumor is chosen ( Figures 15.1 and 15.2 ). In most patients, the skin incision is chosen to provide optimal scar camouflage by placing it in a skin crease, hiding it on a posterior surface of the eyelid (transconjunctival incision), or placing it adjacent to prominent anatomic landmarks such as the eyebrow or eyelashes ( Figure 15.3 ).
Anterior Versus Deep Tumors
The anterior-posterior position of a mass within the orbit is the most important factor to consider in choosing a surgical approach. Tumors anterior to the equator of the eye are most commonly approached from the front of the orbit using a type of anterior orbitotomy. Tumors posterior to the equator of the eye require more advanced deep surgical approaches. The choice of orbitotomy for deep tumors depends on the relationship of the tumor to the optic nerve.
Relationship To the Optic Nerve
A fundamental principle of orbital surgery is
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Choose an orbitotomy approach that avoids crossing the optic nerve
Following this guideline, deep orbital tumors lateral to the optic nerve are approached with a lateral orbitotomy approach. Removal of the lateral orbital wall provides excellent access to these tumors.
Deep tumors medial to the optic nerve are more difficult to reach because there is no bone that can be easily removed to provide good exposure and access. The surgical spaces of the medial orbit can be reached through deep medial orbitotomy approaches, through either the eyelid or the conjunctiva. Access to the apical medial orbit from these anterior orbitotomy approaches is limited. In unusual situations, the medial orbital wall may be removed and limited access to the deep medial orbit can be obtained ( Figure 15.4 ).
Type of Biopsy
The surgical approach may be influenced by the goal of the operation. It is easier to perform an incisional biopsy through a small incision than it is to perform an excisional biopsy. For example, an incisional biopsy of the optic nerve can be performed through either a transconjunctival anterior orbitotomy or a lateral orbitotomy approach. Excision of the entire optic nerve, however, requires a much wider area of exposure, usually provided only by a transcranial orbitotomy approach. You can see that the intent of the operation is a factor in your choice of orbitotomy approach ( Table 15.1 ).
| Location | Surgical procedure |
|---|---|
| Anterior to the equator of the eye | Anterior orbitotomy |
| Posterior to the globe and lateral to the nerve | Lateral orbitotomy |
| Posterior to the globe and medial to the nerve | Deep medial anterior orbitotomy |
| Posterior one third of orbit, optic canal, chiasm | Transcranial and transnasal orbitotomy |
Surgical Spaces of the Orbit
The surgical spaces of the orbit, already discussed in Chapter 2, Chapter 13 , are
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Intraconal space
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Extraocular muscles
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Extraconal space
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Subperiosteal space
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Tenon’s space
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Extraorbital space
You should already know these spaces ( Figure 15.5 ). This section is intended as an illustration of how you can begin to think of the spaces of the orbit and their relationship to the orbitotomy approach. Don’t memorize the specific pathologic processes and approaches mentioned here. We talk about them again later in this chapter. Just start to get an idea of how you are going to choose the orbitotomy approach, based on the position of the pathologic process and what you have already learned in this chapter.
The extraconal space contains the lacrimal gland, superior oblique muscle and trochlea, and nerves and vessels in the extraconal orbital fat. An enlarged lacrimal gland is often palpable in the upper lid and then is readily accessible through an anterior orbitotomy using the upper lid skin crease approach. Lymphoid tumors are among the most common orbital masses. Because lymphomas tend to occur in the lacrimal gland or elsewhere anteriorly in the extraconal fat, anterior orbitotomy approaches to the extraconal space are commonly used. When a lacrimal gland mass is not palpable (mostly posterior to the globe), a lateral orbitotomy, usually with bone removal, is required. The superior oblique muscle and trochlea are in the medial portion of the extraconal space, but rarely require biopsy. Schwannoma of the frontal nerve may be seen in the superonasal quadrant and can be approached anteriorly, but if the mass extends into the apex, a transcranial approach may be necessary for removal. The anterior portion of the superior ophthalmic vein lies in the extraconal space, but it almost never requires surgical intervention.
The intermuscular septum lies between the anterior portion of the extraocular muscles, separating the intraconal and extraconal spaces. The muscles may become involved in neoplastic or inflammatory processes. The most common condition is thyroid orbitopathy. Painful inflammation of the muscles, myositis, may also occur. Primary neoplasms of the muscles are very rare, but metastatic lesions do occur. Although biopsies are not often performed on the extraocular muscles, the muscles can be approached surgically through anterior orbitotomy incisions if the pathologic lesion is anterior. If the enlargement of the muscle is posterior, you can decide on the best approach for incisional biopsy following the principles described in the previous section. The extraocular muscles are important surgical landmarks to guide your surgical dissection. During lateral orbitotomy approaches, the intraconal space is usually entered between the lacrimal gland and the lateral rectus muscle. We discuss this dissection technique further in the section Approach to Deep Lateral Lesions: The Lateral Orbitotomy.
The subperiosteal space is the potential space between the orbital bones and the periorbita. A hematoma may collect in this space from an adjacent fracture. A collection of pus, a subperiosteal abscess, may collect medially from an adjacent ethmoid sinus infection. For drainage of a subperiosteal abscess, you usually approach the medial subperiosteal space anteriorly through the skin and conjunctiva with elevation of the periorbita from the orbital rim and dissection posteriorly along the medial orbital wall (frontoethmoidal and transcaruncular anterior orbitotomy). Repair of orbital floor fractures begins with surgical approaches to the subperiosteal space using transconjunctival or transcutaneous lower eyelid anterior orbitotomy techniques. Similarly, you can approach medial wall fractures using the transcaruncular anterior orbitotomy technique.
The Tenon’s space lies between the eye and the fibrous capsule, or Tenon’s capsule, which surrounds all but the anterior portion of the eye. You may have already operated in this space when performing an enucleation or scleral buckle procedure. Although we usually don’t think of it, these operations start with a transconjunctival anterior orbitotomy. Tenon’s space is rarely involved in pathologic processes; one example is the extraocular extension of a choroidal melanoma.
The extraorbital space includes all the tissues surrounding the orbit: bone, brain, sinus, nasal tissues, skin, and conjunctiva. You are already familiar with some of the many problems that originate in these tissues and involve the orbit secondarily. For many of these tissues, the surgical approach is obvious, whereas for others, decisions require input from other surgical specialties for which interdisciplinary cooperation is essential to the success of the operation.
We talk about the orbital spaces in the context of the orbitotomy procedures again and again throughout this chapter; so start thinking of these spaces in the context of orbitotomy approaches.
Names of Orbitotomy Approaches
There is no consistent nomenclature or classification of orbitotomy approaches. Most of the names used in this text and by other surgeons are descriptive. You shouldn’t memorize these terms because they can mean different things to different people. Some commonly used descriptive terms and my interpretation of them are
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Anterior orbitotomy means that the approach is from the front of the orbit, usually through the eyelid or conjunctiva. In general, an anterior orbitotomy approach does not involve bone resection.
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Lateral orbitotomy means that the approach is from the lateral side of the orbit. In general, the term lateral orbitotomy implies that the lateral rim will be removed. A lateral orbitotomy can be performed through a small skin incision at the lateral canthus without any bone removal.
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The terms anterior and deep are opposite. The term superficial orbital tumor is not used. Anterior tumors are palpable and accessible by the anterior approaches. Deep is usually used to describe posterior tumors in the orbit.
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Anatomy accessible only via transcranial orbitotomy includes the posterior one third of the orbit, superior orbital fissure, sphenoid wing, and chiasm.
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Deep tumors are posterior to the globe. I use the term deep medial anterior orbitotomy for approaches to intraconal tumors medial to the nerve. As we discussed above, the lateral orbitotomy is used for approaches to deep tumors lateral to the nerve.
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Apical implies the posterior one third of the orbit. I use the term orbitocranial to describe tumors involving the orbital apex and optic canal, chiasm, superior orbital fissure, or other intracranial structures. The transcranial orbitotomy is used to approach apical or orbitocranial tumors. The terms superotemporal orbitotomy and panoramic orbitotomy are types of transcranial orbitotomy approaches.
Review the P ’s of the orbital examination and the approach to the patient with proptosis. You should know the P ’s by memory. You should also understand the flow from history and physical examination to imaging to differential diagnosis and, finally, to biopsy or treatment.
State in your own words how each of these factors influences the choice of orbitotomy:
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Anterior or deep location
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Position relative to the optic nerve
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Surgical space occupied
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Goal of biopsy, incisional or excisional
Preoperative Considerations
Before orbitotomy, the patient should have a general medical examination with an emphasis on the cardiopulmonary system to receive clearance for surgery. The blood pressure should be optimally controlled before orbitotomy. All anticoagulants including warfarin, aspirin products, and nonsteroidal antiinflammatory agents should be discontinued before surgery, if possible.
Preoperative informed consent should be obtained. Damage to important neurovascular structures is possible but rarely occurs. Postoperative swelling, diplopia, and upper eyelid ptosis are common but usually resolve. In rare patients, blindness may occur because of intraoperative injuries to the optic nerve or postoperative hemorrhage. Patients undergoing deep orbitotomy procedures are usually hospitalized overnight. The visual acuity is checked every 2 hours for the first 12 to 24 postoperative hours. Death is an extremely unlikely occurrence during an orbitotomy procedure.
If the orbitotomy is part of a multidisciplinary procedure, the division of responsibilities among the various surgical subspecialists should be clearly outlined. If you anticipate an unusual diagnosis, preoperative discussion with the pathology team is appropriate.
Intraoperative Considerations
Room Setup
You should have a plan for the setup of the room and any specialized equipment required. If you anticipate using an operating microscope, it should be positioned and adjusted while the patient is being prepared. Any pathology requisitions should be filled out before you start the surgery. You should discuss the plan for operation with the nursing staff before beginning the procedure.
Orbital Instruments
Specialized orbital instruments are used ( Box 15.1 ). Retraction of skin is necessary, using small (Storz double-fixation forceps) or large (Joseph) skin hooks and suture retractors (4-0 silk). Retraction of the orbital fat is facilitated with Sewall and malleable ribbon retractors of various lengths. Neurosurgical cottonoids placed under the retractors prevent fat prolapse into the surgical wound. A variety of periosteal elevators should be available, including Freer, Joseph, and Dean elevators. Bone removal equipment, including a power saw, drill, and bone rongeurs, is necessary if deep orbitotomy procedures with bone removal are anticipated. A microplating system is useful to repair complex orbital bone cuts. A Freer elevator or a long cotton-tipped applicator is a useful orbital dissection tool. Small neurosurgical dissectors can be helpful.
* Note: Bausch+Lomb owns Storz instrument company. Part numbers are also listed under bauschinstruments.com . Ophthalmic instruments begin with the letter E. ENT instruments begin with the letter N. The company Storz Ophthalmic Instruments should not be confused with the company Karl Storz, which makes endoscopes. Codman instruments are now found at Symmetry Surgical, Inc.
Retractors
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Skin retractors
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4-0 silk traction suture, reverse cutting (Ethicon 783G G-3 single-armed cutting needle)
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4-0 silk, taper needle for bridle sutures under extraocular muscles (Ethicon K-871 RB-1 needle)
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Joseph skin hooks: large double-pronged skin hooks (Storz N4730)
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Storz double-fixation hooks: small double-pronged skin hooks (Storz E0533)
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Orbital retractors
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Sewall retractors
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7 x 52 mm blade (Storz N3321)
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9 x 44 mm blade (Storz N3322)
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11 x 56 mm blade (Storz N3323)
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13 x 70 mm blade (Storz N3324)
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Malleable ribbon retractors (brain spatula)
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Symmetry (Codman) ribbon retractor
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5/8 × 8 in (50–5638)
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3/4 × 8 in (50–5639)
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1/4 in special order (22-0006)
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Neurosurgical cottonoids (Johnson and Johnson Codman surgical patties J-J801407)
Periosteal elevators
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Freer septal elevator: light elevator (4.5 mm Storz N2348, 6.5 mm Storz N2349)
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Joseph periosteal elevator: heavy, but narrow elevator 4 mm (Storz N4610)
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Dean periosteotome: heavy elevator 8 mm (Ambler surgical)
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Cottel septum elevator: rounded elevator (Storz N4660)
Bone instruments
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Kerrison rongeur (upbiting 90 degree)
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No. 0 Extra Small (Storz N1950)
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No. 1 Small (Storz N1951)
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No. 2 Medium (Storz N1952)
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Leksell laminectomy rongeur: large bone rongeur (Codman 53–1125)
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Spurling Kerrison rongeur
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Angled 40-degree upbiting, 3 mm (Codman 53–1515)
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Angled 90-degree upbiting, 3 mm (Codman 53–1516)
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Angled 90-degree downbiting, 3 mm (Codman 53–1517)
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Hall microsagittal saw
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Hall Surgairtome (air drill)
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Bien drill (electric drill)
Dissectors
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Freer elevator (Storz N2348)
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Cotton-tipped applicator, 6 inch
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Neurosurgical dissectors (Rhoton)
Scissors
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Westcott tenotomy scissors, curved right, blunt tips (Storz E3320 R)
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Yasargil micro bayonet scissors, curved, sharp tip (Symmetry Surgical 58–1621 and 58–1921)
Forceps
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Gruenwald nasal dressing forceps, delicate bayonet (Bausch N2862)
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Storz ear forceps (alligator type) (Bausch X0240)
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Storz sinus cup forceps: small cup biopsy forceps, useful for biopsies and retraction of friable tumor tissue (Bausch N2898)
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Takahashi nasal forceps: ethmoidectomy forceps (Bausch N2997)
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Hartman–Herzfeld 3-mm cup forceps: small upbiting angled forceps (Bausch N0965)
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Wilde nasal forceps for ethmoidectomy procedures
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Straight (Bausch N2980)
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Upturned (Bausch N2982)
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Blakesley nasal forceps: smaller forceps for ethmoidectomy procedures (Symmetry Surgical straight 63–2012)
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Cautery
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Colorado microdissector needle
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Bipolar cautery (Sutter 0.7- and 0.4-mm tips)
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Bipolar cautery (long bayonet tips for deep dissection)
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Microbipolar cautery, long bayonet tips (Yasargil) (Storz S2050 38D)
Hemostatic agents
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Bone wax
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For improving platelet aggregation
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Gelfoam (absorbable gelatin sponge)
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Surgicel (oxidized regenerated cellulose)
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Avitene (microfibrillar collagen)
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For improving clotting
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Thrombogen (thrombin)
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Thrombin and Gelfoam
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FloSeal (thrombin and gelatin granules)
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TISSEEL (fibrin glue)
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Stammberger SINU-FOAM (carboxymethylcellulose)
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Suction
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Baron suction tube, 5 French (Storz N0610)
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Frazier suction tube, 9 French (Storz N2421)
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Yankauer tonsil suction tube (Storz N7550)
Headlight
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Integra LED headlight REF 90500
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HEINE ML4 LED headlight
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Several loupe-mounted headlights are available
Head-mounted camera
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Designs for vision NanoCam (used for many of the videos included)
Instrument websites of interest
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Symmetry Surgical: symmetrysurgical.com/en/content/catalog
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Bausch+Lomb Instruments: bauschinstruments.com
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FCI: fci-ophthalmics.com/products/lacrimal-1258/monocanilicular-intubation
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Ethicon US (wound closure): ethicon.com/na/epc/search/keyword/1698?lang=en-default
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McKesson: mms.mckesson.com/catalog/category?node=8962
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JEDMED: jedmed.com/pages/ophthalmology-equipment
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Storz: storzeye.com
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Zimmer Biomet: zimmerbiomet.com/
As discussed in Chapter 1 , scissors and forceps for deeper orbital procedures are usually longer than eye instruments for routine procedures. Bayonet-type handles allow comfortable hand positioning without blocking visualization in deep surgical wounds, especially when an operating microscope is used. The Yasargil neurosurgical scissors (which looks like a long-handled Westcott scissors) with curved or straight blades is good for deep dissections. The Westcott scissors is used in anterior orbitotomy procedures. Most eyelid forceps (Paufique forceps) work well for anterior orbital approaches. Myringotomy forceps or any of a variety of small cup biopsy forceps are useful for grasping tissue in deep or tight spaces. The cup forceps or a small nasal bead forceps (Hartman–Herzfeld 3-mm cup forceps) is useful for small biopsies of friable tumor tissue. A variety of cautery forceps are helpful, especially the micro bayonet bipolar forceps (Fischer or Yasargil bipolar forceps) for deep procedures.
Illumination and Magnification
Excellent illumination is needed to visualize the orbital structures. You can perform anterior orbitotomy procedures with standard operating room lights. A fiberoptic headlight is helpful for any deeper orbitotomy procedures. The coaxial lighting and view provided by the operating microscope is the only way that both the surgeon and the assistant can see deeper orbital structures at the same time.
Magnification using surgical loupes is standard for anterior orbitotomy procedures. Loupes (2.5 or 3.5 power wide field) from Designs for Vision (Bohemia, NY, designsforvision.com ) are expensive but great. Headlights are great for extra illumination with anterior orbitotomies. There are several brands of battery-powered headlights that don’t require you to be tethered to a light box. These are worth the investment (Integra LED headlight REF 90500, integralife.com ). Loupe-mounted lights are also available. Ideally these lights should be lightweight and bright and have a long battery life. I do not use these, but many colleagues do. I want a light that provides an aperture that can be varied so that the bright light surrounding a deep dissection does not bleach out your view of the dark hole in which you are working. I have not found a loupe-mounted light that does this, but there may be one. For deep orbitotomy procedures, I start with loupes and a headlight. As I get into the orbit I use the operating microscope for magnification and illumination. I have to stress this. If you are not using a microscope you are not doing the best job possible. You and your assistant will see so much better when using one that you will never go back to loupes alone. The optimal microscope for orbital surgery is mounted on a counter-weighted stand that allows the microscope to be positioned in any direction in three-dimensional space. These stands are commonly used by your neurosurgical colleagues. The gold standard is operating microscopes made by Zeiss ( zeiss.com ). A variety of configurations are available, but opposing microscope heads are ideal for lateral orbitotomy procedures. A 300-mm objective lens provides an adequate distance between the patient and the microscope so that the longer orbital instruments can be moved in and out of the operating field without hitting the microscope.
For these cases, and really all your cases, it is important to keep the staff involved. We project the operative view onto a wide-screen monitor whenever possible. For recordings I often use the loupe-mounted Designs for Vision DayLite NanoCam, which takes great high-definition videos in the surgeon’s view (many of the videos in this edition have been made using this camera). A downside of any headlight-mounted camera is that your head movements are recorded, so you have to hold your head still to get a good video. We also use a Sony high-definition video camera custom-mounted in the ceiling of the operating room. This has tremendous imaging and great zoom power. In my case, the images from this camera are not viewed or recorded in the surgeon’s view (some of these images are seen in the surgical videos for this chapter).
Body Mechanics and Posture
This is a good place to remind you to pay attention to your posture and body mechanics as a surgeon. If you are lucky, you will spend many hours a week for many years in the operating room (so far for me, over 30,000 hours!). In your early years as a surgeon, it is easy to abuse your body, often operating in awkward positions and craning your neck to see the field or pass a suture. Over time, operating with the microscope presents its own set of problems, especially for your neck. If you are not careful, this neglect, combined with the poor posture you may have assumed during many hours of studying, can lead to a slumped posture and a feeling that your neck is growing from your chest, not your shoulders. It is easy to ignore this in your early career, but all you have to do is look at the posture of your senior staff to recognize that the hanging head position with rounded shoulders is an occupational risk. Long procedures start to take a toll on your aging body. So make it a habit to adjust the table and seat height for each case. Make your shorter assistant use a step stool so you don’t have to hunch over the operating table. Set the microscope so it can be used with your arms and head in a comfortable, natural position. Order the slight downward tilt on your loupes, known as the dental angle. This small change helps you keep your head a bit more upright while operating. Consider stretching breaks during the day. We spend most of our day hunched over in flexion. Between cases, get up and extend your back, neck, and shoulders. Yoga is an especially good way to practice body extension and maintain flexibility. Keep fit. It pays off over time.
Most of us enjoy the adrenaline rush of a tough case and a full schedule. I am a perfect example. We are often unaware of the stress that this exerts on our body. Everyone is different, but none of us is immune to these effects over time. Keep that in mind. Currently, meditation is in fashion; it’s a good practice. It takes only a few minutes a day, keeps you grounded, and helps you to enjoy the journey, not just the destination. Along the same line, consider the effect of your daily stresses and long work schedule on your family. We all think we are more important than we really are; maintaining your family life is the most important role that you have.
Exposure and Intraorbital Dissection
Adequate surgical exposure begins with well-chosen surgical incisions. You should choose a hidden, or camouflaged, incision as close to the orbital mass as possible. If you choose an incision that produces a minimal scar, your resistance to making an incision that is long enough to give adequate exposure is decreased. When the skin and muscle layers of a transcutaneous approach are opened, use 4-0 silk suture retractors to hold the wound edges apart.
Remember that as you dissect deeper into the orbit, you should make the deep portions of the surgical wound at least as wide, or wider, than the initial skin incision ( make the wound A shaped rather than V shaped ). Use a hand-over-hand dissection technique with the orbital retractors to move into deeper orbital tissues ( Figure 15.6 ). As with dissections elsewhere, the key to an effective dissection is to gently spread or pull the involved tissues apart. When you get to a point where you cannot pull the layers apart with the Sewall or malleable retractors, ask your assistant to hold the retractors, keeping the tissue on stretch. You can then use additional blunt dissection with the Freer elevator or cotton-tipped applicator. You can use cautious sharp dissection with a Westcott or Yasargil scissors to open the connective tissue planes of the orbit if blunt dissection through a plane of tissue is too difficult. When the plane is open, use the hand-over-hand technique with the retractors until you reach the structure for which you are looking. If you get lost, put your finger in the wound and reorient yourself (this is a very important step). It is easy to pass by a lesion or anatomic landmark.
Look at Figure 15.7 showing an optic nerve sheath fenestration as an example of how we get the best exposure. Don’t worry about doing this operation; it’s a bit advanced. Just understand the exposure process. You will use it on every case! First, position the eye inferiorly and laterally with sutures. You then stabilize the eyelid with a lid margin traction suture. You want the tissues to remain still while you move the cutting tool across the stationary tissue. Next, open the skin and muscle with the microdissection needle and begin the blunt dissection posteriorly with Sewall orbital retractors. Using the hand-over-hand technique, pull the tissues apart. For this procedure, you want to stay within Tenon’s capsule, aiming for the optic nerve. It is quite easy to miss the nerve if the eye is rotating, so make sure the globe is fixed. The best landmark for the optic nerve is the ciliary vessels. Once you see the color of the vessels you know you are there. At times, you are very close, but you cannot see the landmark for which you are looking. Palpation can be very helpful for showing you where you are in relation to where you want to be (your little finger is best here). If you cannot get a finger in the wound, use the Sewall retractors to “strum” the nerve. Once you have identified the nerve, place the retractors in the very same orientation to isolate the nerve from the surrounding fat. Try not to disturb the fat; be gentle. It is easy to dissect beyond the nerve if you are not careful. Once you see the nerve, place dampened neurosurgical cottonoids (1/2-inch wide by 3 inches long) into the wound using a bayonet forceps. Reposition the retractor over the cottonoid to push the fat behind the retractor and prevent the orbital fat from prolapsing around the retractor. You may remember the analogous general surgical technique of packing the bowel off with a lap sponge to allow exposure of the abdominal surgical wound. Repeat this using three or four cottonoids to expose the wound (see Figure 15.7 ). With the cottonoids in place, you can remove or reposition the retractors without the surgical wound collapsing on itself. That is really the difficult part of this operation. It is a bit scary and awkward to achieve the proper hand positioning to cut the dura in that hole, but you get used to that. Once the nerve is isolated, grasp the dura a few millimeters behind the globe with a forceps and cut through the dura. You see a gush of fluid. Then complete the fenestration (window) so that it is about 3 mm x 5 mm. Again, the process is important. You need good lighting (microscope) and good exposure (technique) to do any procedure.
During your entire dissection you should learn to use both visible and palpable landmarks to navigate through the orbital tissues.
If you find that exposure is poor, inspect the wound. There may be a band of periorbita or other tough tissue resisting your retraction. Don’t be afraid to lengthen your incision if visualization is poor or you are struggling with a lack of room to move within the orbit. Consider an alternative or additional orbitotomy approach if you cannot safely reach the goal of the orbitotomy with the original plan (see Combined Orbitotomies below).
Learn to use orbital retractors safely. It is easy to lose track of time when you are concentrating on the dissection. Remember to have your assistant release the pressure on orbital tissues intermittently to maintain blood flow to the orbital tissues. With cottonoids in the wound, you can relax the retractors without losing your place. Avoid toeing in on the orbital retractors to prevent damage to the orbital tissues. Suture retractors or self-retaining retractors, such as the Jaffe lid speculum, are safe for retraction of the tissues during an anterior orbitotomy, but self-retaining retractors should not be used deep in the orbit.
As we discussed in Chapter 1 , you cannot underestimate the help that an experienced assistant can give you, especially in a deep orbitotomy. The anticipation and facilitation of the assistant provide you with a third and fourth hand. This is necessary because it is not possible for the surgeon alone to retract the deep wound open and perform a dissection or biopsy. If you are dissecting out an orbital mass:
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The assistant should use a retractor to pull the fat away from the mass as you pull the mass away from the fat with your nondominant hand. You can use a forceps, a cotton-tipped applicator, a suction tube, or a retractor
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You can then use your dominant hand to bluntly or sharply separate any bands of tissue on stretch between the fat and the tumor. You can use a pair of scissors or a Freer elevator. Read this again!
This is a basic and important technique for you to know and use for all surgical dissections. If you don’t understand this, ask an experienced surgical colleague to explain and demonstrate this principle to you. You must understand this technique to function effectively as a surgeon ( Figure 15.8 ). When I am having trouble with an orbital dissection, I remind myself of this basic concept. Probably the tissues are not being pulled apart by either my assistant or me.
I am a strong advocate of using the microscope for deep orbital dissections. The light provided by the scope is invaluable for visualization of the delicate structures with which you work. Using the microscope is the only way that both you and your assistant can see in the hole. Whenever possible, display the operative image in the operating room so the staff can stay engaged. Remember, the staff should anticipate and facilitate, but they cannot do so if they can’t see what is going on.
Hemostasis
Intraoperative hemostasis begins with preoperative preparation. Have the patient discontinue any medications with an anticoagulant effect. Aspirin and other platelet-inhibiting medications are very common and should be stopped prior to most orbital cases, if possible. Some herbal remedies have an anticoagulant effect (the 3 G ’s—garlic, ginkgo, and ginseng—and high doses of vitamin E). Make sure that blood pressure is controlled. Intraoperatively, place the patient in the reverse Trendelenburg position. Inject local anesthetic containing epinephrine into the location of the proposed skin incision before prepping and draping the patient. Intraoperatively, control of the blood pressure is important.
You must learn how to cauterize tissues if you are planning to do any orbital surgery. Short and long nonstick bipolar cautery works well in the orbit (Stryker bipolar silver guide). Long microbipolar forceps with fine tips are best. Turn the power down on the cautery control unit when cauterizing in the orbit. Minimize the amount of cautery that you use. In the past, surgeons were taught not to use monopolar cautery in the orbit. I, and many other surgeons, have used the microdissection needle on low settings without any problems, especially for excision of fat during orbital decompression. I am not aware of any study that testifies to its danger or safety, however.
Small amounts of blood in the surgical wound can be evacuated with cotton-tipped applicators. Larger amounts of blood require the use of a small suction tube such as a Baron suction tube (several sizes available). Hold the suction tube in your nondominant hand. Avoid closing the hole in the suction tube near your finger to prevent orbital fat from being sucked into the tubing. Suctioning over a neurosurgical cottonoid, or against a cotton-tipped applicator, also prevents fat from being sucked into the tubing.
Bleeding from bone or diffuse orbital oozing is not easily treated with bipolar cautery. Bone wax should be used to stop bleeding from the orbital bones. Several materials are available to promote coagulation when oozing occurs in orbital tissues. Products that promote platelet aggregation include Gelfoam (absorbable gelatin sponge), Surgicel (oxidized regenerated cellulose), and Avitene (microfibrillar collagen). The coagulation effect occurs early in the clotting cascade, so the latter parts of the cascade must be functional. Topical Thrombogen (thrombin) works a step later in the cascade stimulating the conversion of fibrinogen to fibrin. A favorite technique of mine is to use pieces of Gelfoam soaked with thrombin. This combination stimulates two parts of the clotting sequence. These products are useful to stop lesser degrees of bleeding in the orbit when no point source responsible for the bleeding can be identified. All are absorbable over days and weeks. All swell, so they should be used with caution in the orbital apex. For troublesome bleeding, especially around the dura, FloSeal ( floseal.com ) and TISSEEL ( tisseel.com ) are especially helpful. FloSeal contains bovine thrombin suspended in gelatin granules, so the mechanism is similar to the Gelfoam/thrombin combination. The mix sticks to wet tissue and does not swell to the degree that Gelfoam does. TISSEEL (a fibrin glue) contains human fibrinogen, bovine thrombin, and an antifibrinolytic agent (to stabilize the clot). FloSeal tends to be more useful for cranioorbital applications, but you should know about both. Your neurosurgical and ear–nose–throat (ENT) colleagues can give you tips on how to use these materials.
A variety of resorbable hemostatic agents are available for intranasal and sinus bleeding. These include Stammberger SINU-FOAM (carboxymethylcellulose [CMC] foam, smith-nephew.com ), NASASTENT (CMC in pledget form), and Nasopore (a proprietary polymer in pledget form, stryker.com ). All work well to control bleeding and help to prevent nasal adhesions. The pledgets provide some compression on the bleeding source. The Rhino Rocket is a nasal packing (with a tampon type applicator) made of an expandable sponge-like material (PVA Expandable foam, mooremedical.com ). Rapid Rhino (CMC-coated fabric, rapidrhino.com ) is another type of removable packing. Most of my experience is with SINU-FOAM, Nasopore, and Rhino Rocket. They all work well and can save you and your patient a lot of trouble.
Intraoperative Flexibility
The ability to modify your surgical plan intraoperatively is a sign of an experienced and mature surgeon. You may determine that the lesion is not what you expected it to be. You may need to change the goal of the operation from an excisional to an incisional biopsy or vice versa. You may need to increase the surgical exposure by lengthening the initial incision. You may choose an additional or alternative surgical approach if necessary. You must learn to think on your feet while operating. In your early experience, consider alternative plans A, B, and C before you start the operation. Having well-thought-out options makes the case go more easily and makes the time in the operating room less stressful for you and others around you.
Handling Biopsy Specimens
The goal of many orbitotomies is incisional biopsy of an unknown orbital mass. To obtain an accurate diagnosis, you must learn how to provide the best tissue sample possible. Choose a biopsy site that appears to be representative of the entire tumor. If the tumor varies in appearance, consider more than one biopsy site. Avoid damaging the specimen with forceps or cautery.
Provide as large a tissue sample as practical. If you are unsure whether the sample is representative of tumor or large enough for analysis, you may want to send a portion of the sample for frozen-section analysis. It is not reasonable to expect the pathologist to give you the final diagnosis based on a frozen section, but the pathologist can assure you that the tissue is adequate in size and quality. You may want to leave the operating room and look at the frozen section with the pathologist.
Prevent desiccation of the specimen by placing the tissue in the proper fixative as soon as possible. For routine permanent tissue analysis, place the tissue in formalin. If you suspect a lymphoid tumor or an unusual diagnosis, you should submit fresh tissue in dampened gauze to be frozen for flow cytometry and immunohistochemical staining. Immunohistochemistry can usually be done on paraffin-embedded tissue, however. In all but the rarest of situations, immunopathologic examination has replaced electron microscopic examination. Genetic testing can be done on some primitive tumors, such as rhabdomyosarcomas. If you think you are dealing with an unusual tumor, it is worthwhile to let your pathologist know ahead of time, to make sure that no additional testing or unusual handling of the specimen might be helpful.
