[Complications of endonasal surgery of the paranasal sinuses. Incidence and strategies for prevention].

BACKGROUND: Complications of endonasal surgery continue to occur despite improved optical instruments and surgical techniques. The clinical course of our patients was analysed to develop strategies for a safer surgical technique.

PATIENTS: At the Department of Otorhinolaryngology, Head and Neck Surgery, University of Kiel, 1172 patients (2010 operated sides) were treated between 1986 and 1990 for chronic sinusitis by endonasal paranasal sinus surgery.

RESULTS: The following intraoperative complications were observed: dural injury in 0.8% of the patients (0.5% of the operated sides), retrobulbar hematomas in 0.25% of the patients (0.15% of the operated sides), and hemorrhages requiring transfusion in 0.8% of the patients (0.5% of the operated sides). No injuries of the orbital muscles, the optic nerve, or the carotid artery were observed. Endonasal dacryocystorhinostomy was performed in 195 patients, 15% of whom had previously had paranasal sinus surgery. Endonasal frontal sinus surgery type II or III was performed in 40 patients between 1953 and 1993. A past surgical history-mostly extranasal frontal sinus surgery according to Ritter-Jansen and Lathrop-was found in 80% of these patients. Of 12 mucoceles of the frontal sinuses, 10 had developed after extranasal procedures whereas two developed spontaneously.

CONCLUSION: This analysis shows that the occurrence of severe intraoperative complications can be minimized if certain guidelines are followed. When operating in an anterior-posterior direction, one should, to the extent possible, preserve the ethmoid bulla and the middle turbinate as anatomical landmarks as long as possible. The ethmoid bulla indicates the upper margin of the infundibulum even after removal of the uncinate process. There is no danger of injuring orbital structures if one identifies the maxillary ostium on a line going parallel to the floor of the main nasal cavity from the lowest point of the bulla in a posterior direction. The anterior wall of the bulla also forms the posterior wall of the frontal recess. As long as it is preserved it protects the base of the skull when identifying the frontal ostium. The endonasal enlargement of the frontal sinus ostium as a frontal sinus drainge type II or III is safe if the spina nasalis frontalis and the base of the frontal sinus are removed with a drill in an anterior direction. When opening the ethmoid sinus in an anteroposterior direction, an additional imaginary line through the ethmoid bulla running parallel to the floor of the nasal cavity and therefore also to the base of the skull should be observed and not crossed cranially. The medial blade of the middle turbinate represents an important guide to protect the rima olfactoria. It must therefore be preserved. Exposure of the sphenoid sinus should always be performed transnasally near to the septum and below the sphenoid ostium but never through the ethmoid to prevent damage of the optic nerve or the carotid artery. Observation of these guidelines and anatomical structures will prevent mistakes and wrong approaches in the context of endonasal surgery.