eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > Reconstructive Surgery

Orbital Decompression for Graves Disease: Treatment

Author: Michael Mercandetti, MD, MBA, FACS, Consulting Staff, Department of Surgery, Doctors Hospital of Sarasota
Coauthor(s): Adam J Cohen, MD, Consulting Surgeon, Myers Wyse Center for the Eye; Director, Center for Facial Rejuvenation; Andrew Marc Marlowe, MD, Private Practice, Sarasota, Florida; David J Terris, MD, FACS, Porubsky Professor and Chairman, Department of Otolaryngology, Medical College of Georgia; Peter Levin, MD, Associate Clinical Professor, Department of Ophthalmology, Stanford University Medical Center
Contributor Information and Disclosures

Updated: Nov 10, 2008

Treatment

Medical Therapy

Nonsurgical management of Graves ophthalmopathy involves systemic or retrobulbar corticosteroids and external beam irradiation. In patients for whom these modalities are unsuccessful or those who are not considered candidates, surgical decompression may be considered. Medical treatment can also be used in conjunction with surgical decompression.

Surgical Therapy

The technique for endoscopic medial wall decompression, originally described by Kennedy et al and then Metson et al, is summarized below.^7,8 A brief description of the lateral orbital wall decompression, as described by Goldberg et al and other groups, is also included.⁹

Preoperative Details

All patients undergo a complete head and neck examination and ophthalmologic evaluation followed by coronal and axial CT scanning of the orbits and paranasal sinuses. Visual acuity, visual fields, conjunctival and corneal appearance, Hertel measurements, extraocular motility, and symptoms of diplopia are recorded. Obtain preoperative and postoperative photography.

Prepare the patient for endoscopic sinus surgery under monitored anesthesia care or general anesthesia (the authors' preferred approach). After the administration of parenteral antibiotics and intravenous steroids (eg, dexamethasone, 8-12 mg) and topical (oxymetazoline 0.05%) and local (1% lidocaine, 1:100,000 epinephrine) anesthesia, vasoconstriction is achieved, with particular attention to the middle turbinate and the lateral nasal wall.

Intraoperative Details

Medial Wall Decompression

Endoscopic

Perform a septoplasty first if it is needed for exposure. Following this, perform a total anterior and posterior endoscopic ethmoidectomy with sphenoidotomy (to ensure the most posterior segment of the accessible medial orbital wall has been identified) and extended maxillary antrostomy (to provide inferomedial decompression and as prophylaxis against maxillary sinusitis secondary to ostial narrowing as a result of postoperative edema or scarring). Use a Freer elevator or a similar instrument to fracture the medial orbital wall (lamina papyracea). Then gently remove the lamina, taking care not to violate the periorbita because early release of orbital fat has a tendency to obscure the view. This task may be tedious and requires careful use of several instruments, including a Freer elevator, a nerve hook for anterior bone removal, curettes, and Wilde-Blakesley or similar forceps.

In cosmetic cases, try to preserve a strut of bone between the medial and inferior wall decompression to minimize the risk of diplopia. If inferior decompression is to be performed, use a transconjunctival approach.

When the bone of the medial wall has been completely removed (and usually before the lateral wall is addressed), incise the periorbita to liberate the orbital fat and allow decompression. Limiting the depth of the incision is critical to prevent injury to the rectus muscles (especially the medial rectus) and to minimize bleeding. This is accomplished by using a #12 blade on a #7 Bard-Parker handle. The blade is protected with a Steri-Strip, except for the distal 2-3 mm. This technique ensures a sharp cutting instrument each time. Make 2-4 horizontal periorbital incisions, starting from posterior and extending anteriorly.

Beginning with the inferior incision and sequentially moving to the most superior incision is best. This sequence minimizes the propensity of the orbital fat to obscure the subsequent incisions. For ease of incision and to assist with decompression of the orbital contents into the ethmoid vault, which may require additional effort in an irradiated orbit, apply gentle pressure to the globe during this maneuver. Finally, thin strands of periorbita may persist as bands between the horizontal incisions and should be carefully teased free with a nerve hook or similar instrument.

Transcutaneous

Alternative approaches to the medial wall include a transcutaneous incision (such as those used in an external ethmoidectomy approach and a Lynch-type incision). This incision can be enlarged inferiorly with removal of the medial canthal tendon. The floor of the orbit can also be accessed with this approach. The trochlea, through which the superior oblique tendon passes, should be avoided.

Transcaruncular

Still another approach is the transcaruncular approach.^4,10 This approach does not require a cutaneous incision, nor does it require detachment of the medical canthal tendon. In this technique, the entry incision is made medially and posteriorly to the caruncle. This plane allows for access to the posterior lacrimal crest and the more posterior ethmoids.

The medial wall can also be approached with a transcutaneous or transconjunctival approach by continuing the dissection superomedially. Take care to avoid the lacrimal system and the origin of the inferior oblique muscle.

Lateral Wall Decompression

The lateral wall of the orbit may be approached through an upper eyelid incision, lateral incision, lateral canthotomy incision, or vertical incision through the conjunctiva; it may also be approached beneath a coronal flap. The eyelid crease incision may be preferred because it heals well, does not violate the conjunctiva or lateral canthal angle, and allows excellent and rapid access to the orbit.

Carry the eyelid crease incision along a laugh line over the orbital rim, never behind the eyebrow. Use cutting cautery or a laser incisional device to cut through the orbicularis muscle. Leave the orbital septum intact. Laterally, proceed with dissection onto the periosteum of the lateral orbital wall. Using retractors or traction sutures, expose the entire orbital rim. Score the periosteum at the orbital rim and proceed with dissection in the subperiosteal space. Control bleeding from the zygomatico-temporal, zygomatico-facial, or lacrimal foramina with bone wax or cautery. The dissection proceeds to the inferior orbital fissure inferiorly, the frontosphenoidal and frontozygomatic sutures superiorly, and past the zygomaticosphenoidal suture. Use a high-speed drill to break through the thin anterior wall of the lateral orbit and remove the anterior bone with a drill or rongeurs, exposing the temporalis muscle. Remove the bone anteriorly, leaving only a thin bony rim.

Posteriorly, the dissection proceeds into the sphenoid bone, stopping at diploic bleeding or when the dura overlying the temporal lobe is exposed. Use a guarded sickle blade to score the periorbita with 2 vertical strips above and below the level of the lateral rectus muscle. A Freer elevator or forceps may be used to tease out orbital fat.

Orbital Floor Decompression

The orbital floor can be approached in various ways. A direct inferior approach can be via a Caldwell-Luc incision, which is performed transorally in the Ogura approach.⁴ Alternatively, the maxillary sinus can be entered endoscopically and the bone of the orbital floor removed. Avoid damaging the infraorbital nerve. Nonendoscopic alternatives would consist of a transconjunctival lower eyelid approach or a transcutaneous lower eyelid approach, with or without release of the lateral canthal tendon.

Orbital Roof Decompression

This approach is reserved for when other approaches have been tried or an extensive amount of decompression is required. The roof can often be thinned out while avoiding the lacrimal gland. The roof is often accessed via a coronal approach.

Other Techniques

Fat decompression

A standard transcutaneous or transconjunctival approach is used. The extraconal orbital fat is removed with meticulous hemostasis. Accessing intraconal fat involves a deeper dissection.¹¹

Advancements

The lateral orbital wall can be advanced to provide additional decompression. The anterior lateral wall can be resected, advanced, and plated into its new forward position. Valgus rotations, in which the anterior lateral wall is left intact and the posterior part is removed, can be performed.

Postoperative Details

Nasal packing is not used, and the patient is instructed to avoid nose blowing for at least 2 weeks after surgery.

Follow-up

Carefully evaluate the patients in the early postoperative period to ensure maintenance of presurgical level of vision. Examine patients every 1-2 weeks following surgery to ensure proper wound healing. Then, examine them approximately 3-6 months after surgery, when the final result should be attained; postoperative photography may be done if desired.

Complications

Complications of traditional methods of orbital decompression vary with the approach. Complications include diplopia, blindness, epiphora, brain injury, cerebral spinal fluid (CSF) leak, oral-antral fistula, nasolacrimal duct obstruction, and scarring. The endoscopic approach includes all of those risks except for oral-antral fistula. Optic nerve injury has been reported during orbital decompression for Graves disease, but it is rare and may be less likely with endoscopic control because of improved visualization. Complications can include the new onset of postoperative diplopia among patients who undergo decompression for visual loss.

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