[Complications of endonasal surgery of the paranasal sinuses. Special anatomy, pathomechanisms, surgical management].

Statistics show that there is no significant increase in complications in endonasal sinus surgery of the ethmoid or sphenoid as compared to paranasal or transantral procedures. Exact anatomical knowledge of the nasal cavity, the paranasal sinuses and related structures is essential for assessment and management in iatrogenic complications, which are divided in three groups, according to characteristic topographic implications: orbito-ocular, vascular, encephalomeningeal. Orbito-ocular complications are managed by decompression of the orbit using the paranasal approach. Direct lesions of the optic nerve in ethmoid- or sphenoid-sinus surgery are extremely rare and are due to an abnormal nervous course. Vascular complications in the branches of the external carotid artery require local procedures (e.g. transantral ligature of the sphenopalatine artery). In some cases an intra-arterial embolization using supra-selective angiography is more effective. Massive bleeding from lesions of the internal carotid artery is stopped by placement of a balloon catheter combined with a transfemoral intra-arterial digital subtraction technique. Iatrogenic dura defects in the frontal skull base can be managed easily once the lesion has been exactly and clearly localized. Adequate control of the frontobase including the orbit, optic nerve and related vascular and nervous structures is achieved by the extracranial subfrontal paranasal (Killian incision) approach, if endoscopic or endonasal microscopic repair is ineffective.