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Keywords:

  • orbital decompression;
  • diplopia;
  • inferomedial orbital strut;
  • endoscopic orbital floor decompression

Abstract

  1. Top of page
  2. Abstract
  3. Technique
  4. Conclusion
  5. References

Background

Medial and inferior orbital decompression is most commonly performed in the setting of dysthyroid orbitopathy. Diplopia represents the most common complication and may be minimized through the preservation of a bony inferomedial strut (IMS). Historically, this has required a transconjunctival approach due to the technical demands of performing an isolated orbital floor decompression using endoscopic instrumentation. Here we describe a novel technique of a purely endoscopic orbital floor decompression with reliable preservation of the IMS.

Methods

Description of a novel surgical technique for endoscopic orbital floor decompression with IMS preservation using frontal sinus instrumentation visualized by a 70-degree endoscope.

Results

We have successfully used this technique in 12 orbits with 100% preservation of the bony inferomedial strut and no complications. The extent of decompression and width of the residual strut may be fine tuned as needed to optimize results.

Conclusion

Orbital floor decompression with IMS preservation may be reliably performed using purely endoscopic techniques. Successful completion of this procedure requires the adaptation of standard frontal sinus instrumentation to the maxillary sinus roof and thus may be readily mastered by any endoscopic surgeon comfortable with frontal sinus techniques.

Orbital decompression is most commonly performed in the setting of dysthyroid orbitopathy.[1] The goal of reducing intraorbital pressure has not changed since the first description of the lateral canthotomy by Dollinger in 1911[2]; however, the techniques have evolved considerably. The transantral approach to the medial wall and floor described by Walsh and Ogura[3] in 1957 has given way to modern endoscopic techniques first reported by Kennedy et al.[4] This may be coupled with a variety of minimally invasive incisions to enable access the lateral orbital wall.[5] Despite wide variations in technique across institutions, a systematic review suggests that outcomes as measured by proptosis, visual acuity, and intraocular pressures are similar regardless of method. A consequent shift in the emphasis of research toward prevention of morbidity suggests that new onset diplopia is the most common complication with a rate of up to 20%.[6] Efforts to reduce diplopia have included performing a balanced decompression[7] and preservation of a medial periorbital strip[8, 9]; however, perhaps the most effective technique has been preservation of the inferomedial bony strut between the medial wall and floor. This method was first described by Goldberg et al.[10] as a transconjunctival approach and was later converted to an endoscopic technique by Wright et al.[11] in 1999. In patients with preservation of the strut no diplopia was reported; however, due to the technical demands of the procedure, the strut could only be preserved in 71% of orbits. Here we describe a method of exclusively endoscopic orbital floor decompression using standard frontal sinus instrumentation (Fig. 1A) that may be coupled with medial wall decompression and allows for reliable preservation of the inferomedial strut in 100% of cases.

image

Figure 1. (A) Axial CT demonstrating the favorable angulation of frontal sinus instruments for manipulation of structures within the maxillary sinus. (B–F) A 70-degree endoscopic view of the left maxillary sinus roof demonstrating sequential stages of the endoscopic floor decompression with IMS preservation. CT &equals computed tomography; IMS = inferomedial strut.

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Technique

  1. Top of page
  2. Abstract
  3. Technique
  4. Conclusion
  5. References

Step 1

The procedure begins with a maxillary antrostomy with bony removal from the natural ostium to the posterior maxillary wall. Posteriorly, care is taken to create a wide vertical aperture from the orbital floor to the insertion of the inferior turbinate to enhance visualization and access. Complete access to the sinus may be limited in patients with a short vertical antrostomy although the superior aspect of the inferior turbinate may be focally removed as needed. The orbital floor is exposed by stripping the posterosuperior maxillary sinus mucosa and preserving it within the anterior sinus. The mucosa is left intact for the purpose of replacing it at the conclusion of the procedure.

Step 2

The orbital floor is typically thicker than the lamina papyracea and thus under direct visualization using a 70° endoscope, a 4-mm high-speed tapered 70° diamond burr (Medtronics, Jacksonville, FL) is used to thin the bone from the lateral edge of the inferomedial strut to the medial border of the infraorbital canal (Fig. 1B).

Step 3

Once the bone is eggshell thin, a double ball probe may be used to down fracture the bone away from the periorbita, taking care not to expose the orbital fat or inferior rectus muscle (Fig. 1C).

Step 4

The borders of the osteotomy may be further expanded using a frontal sinus “cobra” through-punch (Karl Storz, Tuttlingen, Germany), allowing for fine adjustments to the width of the remaining inferomedial strut (Fig. 1D). Medially, the lacrimal bone represents the anterior limit of the osteotomy, although laterally the angulation of the drill allows for bony removal several millimeters anterior to this.

Step 5

Once the osteotomy is complete the periorbita may be incised, allowing for decompression of the inferior periorbital fat into the maxillary sinus. Blunt dissection of the fine fascial fibers between fat compartments allows for enhanced prolapse of fat while protecting the inferior rectus muscle (Fig. 1E).

Step 6

Once the floor has been deemed adequately decompressed, the previously reflected mucosa is gently laid back into position to hasten remucosalization of the sinus and minimize postoperative crusting (Fig. 1F). The lamina papyracea may be removed either prior to or following this procedure using standard endoscopic techniques.

Conclusion

  1. Top of page
  2. Abstract
  3. Technique
  4. Conclusion
  5. References

We have successfully used this technique in 12 orbits with 100% preservation of the inferomedial strut and no surgical complications. Successful completion of this procedure requires the adaptation of standard frontal sinus instrumentation to the maxillary sinus roof and thus may be readily mastered by any endoscopic surgeon comfortable with frontal sinus techniques. As with all endoscopic orbital procedures, collaboration with an oculoplastic surgeon is essential to provide patients with comprehensive care and optimize surgical outcomes.

References

  1. Top of page
  2. Abstract
  3. Technique
  4. Conclusion
  5. References
  • 1
    Leong SC, White PS. Outcomes following surgical decompression for dysthyroid orbitopathy (Graves’ disease). Curr Opin Otolaryngol Head Neck Surg. 2010;18:3743.
  • 2
    Dollinger J. Die Druckentlastung der Augenhöhle durch Entfernung der äußeren Orbitalwand bei hochgradigem Exophtalmus (Morbus Basedowii) und konsekutiver Hornhauterkrankung. Dtsch Med Wochenschr. 1911;37:1888.
  • 3
    Walsh TE, Ogura JH. Transantral orbital decompression for malignant exophthalmos. Laryngoscope. 1957;67:544568.
  • 4
    Kennedy DW, Goodstein ML, Miller NR, et al. Endoscopic transnasal orbital decompression. Arch Otolaryngol Head Neck Surg. 1990;116:275282.
  • 5
    Leong SC, Karkos PD, Macewen CJ, et al. A systematic review of outcomes following surgical decompression for dysthyroid orbitopathy. Laryngoscope. 2009;119:11061115.
  • 6
    Malik R, Cormack G, MacEwen C, et al. Endoscopic orbital decompression for dyscosmetic thyroid eye disease. J Laryngol Otol. 2008;122:593597.
  • 7
    Bailey KL, Tower RN, Dailey RA. Customized, single-incision, three-wall orbital decompression. Ophthal Plast Reconstr Surg. 2005;21:19; discussion 9–10.
  • 8
    Jimenez-Chobillon MA, Lopez-Oliver RD. Transnasal endoscopic approach in the treatment of Graves ophthalmopathy: the value of a medial periorbital strip. Eur Ann Otorhinolaryngol Head Neck Dis. 2010;127:97103.
  • 9
    Metson R, Samaha M. Reduction of diplopia following endoscopic orbital decompression: the orbital sling technique. Laryngoscope. 2002;112:17531757.
  • 10
    Goldberg RA, Shorr N, Cohen MS. The medical orbital strut in the prevention of postdecompression dystopia in dysthyroid ophthalmopathy. Ophthal Plast Reconstr Surg. 1992;8:3234.
  • 11
    Wright ED, Davidson J, Codere F, et al. Endoscopic orbital decompression with preservation of an inferomedial bony strut: minimization of postoperative diplopia. J Otolaryngol. 1999;28:252256.