Maxillary sinoscopic view of polyps obstructing the natural ostium of the maxillary sinus.

Telescopic maxillary siloscopy via the canine fossa is an excellent way to study the natural ostium of the maxillary sinus. [1-3] The 0[degrees], 4-mm telescope is passed through the maxillary trocar inserted at the canine fossa, and the inside of the maxillary sinus is examined. The tip of the telescope is then directed toward the medial posterior portion of the sinus and gradually advanced upward. You will first encounter the infraostial ridge. The natural ostium is found at the most superoposterior portion of the medial wall of the sinus, just above the infraostial ridge. The shape and size of the ostium vary. [1-3]

In patients with recurrent maxillary sinusitis, one expects to see the obstruction of the natural ostium either on the nasal side (ethmoid infundibulum), on the antral side (maxillary infundibulum), or on both sides. Several cases in which there were obstructions of the natural ostium from the antral side are presented here.

Polyps can obstruct the natural ostium partially (figure, A) or totally (figure, B-D). The patient with a partial ostial obstruction usually responds to medical treatment. In some cases, transnasal endoscopic removal of disease in the ethmoid infundibulum is required. For the patient with a total ostial obstruction who experiences recurrent sinusitis despite repeated medical therapy, endoscopic sinonasal surgery--consisting of the removal of ethmoid infundibulum disease, middle meatal antrostomy, and antral polypectomy--is indicated. It is important that the natural ostium and middle meatal window are connected to prevent the postoperative recirculation phenomenon of maxillary sinus drainage. [2,3] The procedure can be performed under direct maxillary sinoscopic observation. If the transnasal endoscopic approach is technically difficult, the mini-Caldwell-Luc procedure may be employed. [3]

Telescopic maxillary sinoscopy via a trocar placed through the canine fossa is a useful adjunctive procedure for the diagnosis and treatment of ostial lesions of the maxillary sinus. Although this procedure is generally safe, precautions should be taken to prevent complications. The trocar should be carefully inserted and always directed posteriorly, parallel to the nasal floor. It should never be directed superiorly toward the orbit.

References

(1.) Draf W. Endoscopy of the Paranasal Sinuses: Technique, Typical Findings, Therapeutic Possibilities. New York: Springer-Verlag, 1983.

(2.) Stammberger HR. Functional Endoscopic Sinus Surgery: The Messerklinger Technique. Philadelphia: B.C. Decker, 1991.

(3.) Yanagisawa E. Atlas of Rhinoscopy: Endoscopic Sinonasal Anatomy and Pathology. San Diego: Singular/Thomson Learning, 2000.