Image-guided endoscopic excision of ethmoid sinus mucocele.

A 36-year-old man with a history of chronic sinusitis complained of persistent left frontal headaches and left orbital pain. The patient denied diplopia, and physical examination revealed full and symmetric extra-ocular movements. The patient's visual acuity was intact, and he did not have exophthalmos.

Preoperative coronal computed tomography demonstrated opacification of the left anterior ethmoid air cells and a soft tissue mass medial to the left orbit (figure, A). The medial wall of the left orbit was displaced laterally.

The patient underwent imageguided functional endoscopic sinus surgery. A telescopic view revealed thick greenish secretions extruding from a mucocele at the anterior ethmoid region adjacent to the left lamina papyracea (figure, B). With the assistance of computer image guidance, a microdebrider was used to carefully open the mucocele and suction its contents (figure, C).

A thin left lamina papyracea was visible in the exenterated cavity of the mucocele (figure, D). Ballottement of the left globe, with the lids closed, demonstrated within the cavity of the mucocele a corresponding movement at the thin lamina papyracea. The bone of the lamina papyracea, however, was intact, and no orbital contents were noted. Ten months after the surgery, the patient was symptom-free.

Ethmoid mucoceles are chronic, expansile, mucus-filled cysts of the paranasal sinuses. [1] Ethmoid mucoceles can cause headache and orbital pain, [2,3] which were this patient's presenting complaints.

This case demonstrates the utility of performing sinonasal surgery with the assistance of computer image guidance (VTI). Full evacuation of the mucocele without knowing its location in relation to the orbit would have been difficult, especially in light of the monocular view inherent in endoscopic sinus surgery. Confirming proper orientation and positioning with computer image guidance throughout the dissection improved the safety and effectiveness of this procedure. The advantages and disadvantages of intraoperative guidance systems have been discussed by Roth et al and Casiano, [3,4]

No technical advancement is without its limitations, of course, so it is important to realize that a computer-guided system is only a useful adjunct to, not a substitute for, a thorough knowledge of sinonasal anatomy. The intraoperative image-guided system is particularly useful for sinonasal revision procedures and when operating in close proximity to such vital structures as the brain and orbit.

From the Southern New England Ear, Nose, Throat, and Facial Plastic Surgery Group and the Hospital of St. Raphael, New Haven, Conn. (Dr. Fortgang and Dr. Yanagisawa), and the Section of Otolaryngology, Yale University School of Medicine, New Haven (Dr. Fortgang, Dr. Joe, and Dr. Yanagisawa).

References

(1.) Canalis RF, Zajtchuk JT, Jenkins HA. Ethmoid mucoceles. Arch Otolaryngol 1978;104:286-91.

(2.) Moriyama H, Nakajima T, Honda Y. Studies on mucoceles of the ethmoid and sphenoid sinuses: Analysis of 47 cases. J Laryngol Otol 1992;106:23-7.

(3.) Roth M, Lanza DC, Zinreich J, et al. Advantages and disadvantages of three-dimensional computed tomography intraoperative localization for functional endoscopic sinus surgery. Laryngoscope 1995;105:1279-86.

(4.) Casiano RR. Intraoperative image-guidance technology. Arch Otolaryngol Head Neck Surg 1999;125:1275-8.