KEYWORDS

Orbital exenteration; Orbital surgery; Sinonasal neoplasms; Sinus tumors; Advanced endoscopic techniques

Orbital exenteration has traditionally been performed via an open approach for orbital malignancies. The open technique results in significant cosmetic deformity, provides limited exposure to the orbital apex, and leaves an exposed cavity requiring spontaneous granulation or flaps for coverage. The advent of minimally invasive techniques has allowed for consideration of orbital exenteration by using the endoscope as the primary surgical modality. This article describes the author’s technique for endoscopic power-assisted orbital exenteration (EPOE).

© 2008 Elsevier Inc. All rights reserved.

Background

Orbital exenteration is a radical procedure that typically involves the complete removal of all orbital contents, including the globe, eyelids, conjunctiva, and periorbital structures.1 On the basis of the extent and location of the tumor, the exenteration may be subtotal (eyelids left intact) or extended (removal of adjacent bony structures).2 The procedure is most commonly performed for eyelid and conjunctival malignancies with secondary orbital spread or primary orbital malignancies.1,3 Orbital exenteration also may be required for sinonasal malignant neoplasms or fulminant invasive fungal rhinosinusitis with orbital invasion.4 The procedure can result in significant cosmetic deformity with an exposed orbital cavity necessitating spontaneous granulation, split-thickness skin graft, or locoregional or free flaps. Despite adequate reconstruction, chronic complications may arise, including sino-orbital fistula and infection, resulting in delayed healing and chronic crusting.5

The advances in endoscopic techniques have facilitated the management of complex sinonasal and orbital pathology. The endoscopic approaches have been successfully used for the management of nasolacrimal duct obstruction, dysthyroid orbitopathy, and optic neuropathy. This cumulative experience has allowed for the consideration of en-

Address reprint requests and correspondence: Pete S. Batra, MD, Head and Neck Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, A71, Cleveland, Ohio 44195.

E-mail address: batrap@ccf.org.

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doscopic power-assisted orbital exenteration (EPOE). This report describes this novel procedure and outlines its frank advantages and disadvantages over the traditional open approaches for orbital exenteration.

Indications

EPOE typically is indicated for sinonasal malignant neoplasms with secondary invasion of the periorbital soft tissues. It may also be required for fulminant invasive fungal rhinosinusitis with orbital spread.6 EPOE may be considered in both scenarios when the endoscope is used as the primary surgical modality for the management of the respective pathology. This facilitates more natural transition from the sinonasal to the orbital portion of the procedure and allows for better assessment of the sinonaso-orbital interface when making the decision to exenterate. In rare instances, the procedure may be indicated for inflammatory orbital disorders, such as sclerosing inflammatory pseudotumor.

Preoperative assessment

Preoperative surgical planning requires careful review of computed tomography (CT) and magnetic resonance imaging (MRI) to assess the extent of sinonasal and orbital pathology. All patients undergo preoperative ophthalmo-

logic evaluation for baseline ocular assessment. Maxillofacial prosthetic consultation is obtained for postoperative orbital prosthesis. Informed consent for orbital exenteration is obtained after frank discussion of risks and benefits and consideration of pros and cons of the open and endoscopic approaches.

Surgical technique

The surgical procedure is performed under general anesthesia. The operative suite and the patient are set up for standard endoscopic sinus surgery. Nasal decongestion is obtained with the use of 0.05% oxymetazoline hydrochloride on cotton pledgets. Transnasal sphenopalatine and lateral nasal wall injections are performed with 1% lidocaine with 1:100,000 of epinephrine. Large sinonasal neoplasms may preclude intranasal injections; transoral greater palatine foramen block may be used in these circumstances.

The sinonasal portion of the proposed procedure is completed. Important landmarks should be delineated before commencing EPOE. A wide sphenoidotomy is performed and the optic nerve is identified superior to the opticocarotid recess. Maxillary antrostomy is used to define the floor of the orbit. The medial orbital wall is skeletonized from the lacrimal region to the orbital apex. Any residual lamina papyracea is removed with a curette or Cottle elevator. In cases of malignant pathology, the periorbita will have already been eroded. If the bone of the lamina papyracea is thickened by the longstanding disease process, a diamond burr with concurrent irrigation can be used to drill away the medial orbital wall.

Soft-tissue shavers facilitate expeditious removal of the periorbital contents while the suction constantly clears blood from the surgical field. Extraocular muscles, orbital fat, and pathology are debulked with 0-, 40-, and 60-degree

Figure 2 The optic nerve is skeletonized, and the lateral rectus muscle is debulked with the shaver.

and radenoid shaver tips (Medtronic Xomed, Jacksonville, FL) (Figure 1). The optic nerve is skeletonized as the debulking proceeds from medial to lateral and inferior to superior (Figure 2). Typically, the lateral and superior orbital periosteum is not involved by the disease processes originating within the sinuses and therefore can be preserved using this technique. Once the orbital contents are removed, the optic tubercle is drilled to expose the annulus of Zinn and to identify the proximal optic nerve as it emerges from the optic foramen. The optic nerve is clamped at the orbital apex using a long right-angle hemostat.

The globe is subsequently released by making relaxing incisions in the conjunctiva with overhead lighting and

Figure 1 Endoscopic view of left orbital cavity illustrates removal of orbital fat with an angled soft-tissue shaver and delineation of extraocular muscles.

Figure 3 The optic nerve is clamped at the orbital apex to control the ophthalmic artery, and the nerve is transected with an ophthalmic crescent knife.

Figure 4 The orbital apex and the optic nerve stump have been cauterized with suction bipolar cautery.

direct visualization. This is elevated back toward the conjunctival fornix. The globe is mobilized medially and laterally by sharp release of the canthal tendons. Next, the optic nerve is transected sharply proximal to the clamp with an ophthalmic crescent knife (Alcon Laboratories Inc., Forth Worth, TX) (Figure 3). The globe and optic nerve trunk are sent en bloc for permanent pathology. The optic nerve stump is cauterized with bipolar cautery (Figure 4). Frozen sections should be obtained from the orbital apex and optic nerve to ensure adequate frozen section control. Microfibrillar collagen (Avitene, Traatek, Inc., Ft. Lauderdale, FL) mixed with saline is applied to the optic nerve stump and exposed bony surfaces of the orbital cavity. The orbital cavity is packed with petrolatum gauze or 4-cm Merocel sponges (Medtronic Xomed, Jacksonville, FL) and supported by 8-cm Merocel nasal sponges in the nasal cavity. The posterior aspects of the conjunctiva of the upper and lower lids are approximated to one another with 4-0 Vicryl sutures on an atraumatic needle. Gentamicin ophthalmic ointment is applied to the conjunctiva. Through forces of contracture, the lids will eventually retract into the orbital cavity; the orbital prosthesis is fitted directly over the lids.

Discussion

Orbital exenteration has been traditionally been performed by the anterior open approach for primary orbital and sinonasal, eyelid, and conjunctival neoplasms with secondary orbital invasion. The procedure results in an exposed bony cavity that may require spontaneous granulation with average healing time of 5 months.1 Split-thickness skin grafts, regional muscle flaps or free-tissue transfer may also be

performed with its associated donor site morbidity. In addition, the anterior approach provides limited exposure to the orbital apex hindering optimal tumor management in this critical region.

The advent of minimally invasive endoscopic techniques have allowed for consideration of EPOE an as alternate to the open exenteration.4 In a preliminary report, the technique was used successfully in 3 patients with pathology consisting of squamous cell carcinoma, malignant peripheral nerve sheath tumor, and fulminant invasive mucormycosis. All 3 patients had preoperative radiographic involvement of the orbit; intraoperative intraconal invasion was confirmed before making the decision to exenterate. The orbit was exenterated successfully using powered instrumentation in 30 to 45 minutes. The estimated blood loss was100 mL in each case.

EPOE offers several key advantages. The technique provides superb view and exposure to the orbital contents, especially the orbital apex, which is generally limited by the open approaches. It facilitates direct control of the optic nerve and the ophthalmic artery by cross-clamping and bipolar cautery endonasally. The potential preservation of the superior and lateral periosteum minimizes crusting and allows for “mucosalization” generally within 8 weeks. The sparing of the eyelids provides a base for better fitting of the orbital prosthesis. From an oncologic standpoint, the endoscopic approach provides broad exposure to the lateral anterior cranial fossa and middle cranial fossa for tumor resection.

The limitations of EPOE must be carefully considered as well. Primary tumors of the eyelids, globe, conjunctiva, and lacrimal system are better managed by open exenteration; these pathologies should serve as a relative contraindication to the endoscopic approach. Great care and caution must be exercised in managing bulky tumors or highly vascular neoplasms as extensive bleeding may be more difficult to control endoscopically. Finally, the use of EPOE requires endoscopic expertise and specialized equipment and, thus, should only be used by surgeons with considerable experience with advanced endoscopic techniques.

References

1.Nemet AY, Martin P, Benger R, et al: Orbital exenteration: A 15-year study of 38 cases. Ophthal Plast Reconstr Surg 6:468-472, 2007

2.Rubin PAD, Remulla HD: Surgical methods and approaches in the treatment of orbital disease. Neuroimaging Clin N Am 6:239-255, 1996

3.Ben Simon GJ, Schwarcz RM, Douglas R, Fiashetti D, McCann JD, Glodberg RA: Orbital exenteration: one size does not fit all. Am J Ophthalmol 139:11-17, 2005

4.Batra PS, Lanza DC: Endoscopic power-assisted orbital exenteration. Am J Rhinol 19:297-301, 2005

5.Taylor A, Roberts F, Kemp EG: Orbital exenteration—a retrospective study over an 11 year period analyzing all cases from a single unit. Orbit 25:185-193, 2006

6.Eliashar R, Resnicl IB, Goldfarb A, Wohlgelernter J, Gross M: Endoscopic surgery for sinonasal invasive aspergillosis in bone marrow transplant patients. Laryngoscope 117:78-81, 2007

KEYWORDS

Ocular muscle surgery; Endoscopic sinus surgery; Strabismus surgery;

Medial rectus muscle; Thyroid orbitopathy

Ocular muscle surgery is traditionally performed via an anterior, open approach. Excessive dissection within the orbit can lead to fat adherence syndrome. In cases of restrictive strabismus with severe esotropia, the medial rectus rotates to the posterior orbit, making surgery increasingly challenging. Endoscopic sinus surgery has progressed to include procedures in areas adjacent to the sinuses. The orbit, in particular the medial rectus muscle, is particularly suitable for transnasal endoscopic surgery. Situations that could benefit from this technique include strabismus surgery and posttraumatic exploration of the medial rectus. This article describes the authors’ approach to endoscopic ocular muscle surgery.

© 2008 Elsevier Inc. All rights reserved.

The management of sinus disease underwent a major evolution with the development of endoscopic sinus surgery (ESS) techniques.1 Although the initial focus of ESS was on clearance of the obstructed sinuses and ostiomeatal complex in chronic sinus disease, the indications for ESS have since grown to include sinonasal tumors as well as access to the adjacent regions of the orbit and the cranium.2,3 Orbital and optic nerve decompression has been well described in the literature,4 but endoscopic approaches to the ocular muscles as assistance to strabismus procedures is a novel area of involvement for the ESS surgeon.

Within the orbit, the medial rectus (MR) muscle is conveniently located just lateral to the lamina papyracea and can be easily accessed as an extension of orbital decompression. This accessibility would be particularly useful in situations in which there is poor access to the MR or when identification is difficult via the conventional open approach.

In cases of restrictive strabismus with severe esotropia, the insertion of the MR rotates posteriorly, which may

Conflicst of interest: Dr Desrosiers is a consultant to MedtronicXomed on bacterial biofilms in CRS and powered endoscopic sinus surgery.

Address reprint requests and correspondence: Martin Desrosiers, MD, FRCSC, Hotel-Dieu de Montreal, 3840 St Urbain Street, Montreal, QC H2W 1T8, Canada.

E-mail address: desrosiers_martin@hotmail.com.

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happen in cases of Grave’s orbitopathy. With severe contracture, the MR is impossible to access through an open approach. Standard strabismus surgery techniques of suture placement near the muscle insertion and subsequent disinsertion cannot be accomplished safely.

Endoscopic identification and retrieval of the MR is useful in the scenario of the lost or displaced MR. The lost MR is particularly challenging to identify and retrieve because of its lack of attachments to the oblique muscles, unlike the other rectus muscles. Open exploration of a lost MR during strabismus surgery or after trauma is often unsuccessful, and excessive manipulation results in scarring and fat adherence syndrome.5

In a cadaver study, McKeown and coworkers6 has shown that the transnasal endoscopic approach to the MR is feasible, giving sufficient access for endoscopic exposure and suture placement in the stump of a lost MR muscle. There have also been reports of successful retrieval of lost MR, with7 and without8 the use of image guidance systems. This article describes the endoscopic approach to the MR and its application in elective strabismus surgery. It also serves as the basic foundation for future novel endoscopic ocular muscle procedures in the orbit. We have extended these reports by the first description of a successful bilateral endoscopic transection of the MR muscle for severe esotropia in a patient with Graves’s opthalmopathy.9