Danger points, complications and medico-legal aspects in endoscopic sinus surgery. Hosemann W,Draf C GMS current topics in otorhinolaryngology, head and neck surgery Endoscopic endonasal sinus surgery represents the overall accepted type of surgical treatment for chronic rhinosinusitis. Notwithstanding raised and still evolving quality standards, surgeons performing routine endoscopic interventions are faced with minor complications in 5% and major complications in 0.5-1%. A comprehensive review on all minor and major complications of endoscopic surgery of the paranasal sinuses and also on the anterior skull base is presented listing the actual scientific literature. The pathogenesis, signs and symptoms of each complication are reviewed and therapeutic regimens are discussed in detail relating to actual publication references. Potential medico-legal aspects are explicated and recent algorithms of avoidance are mentioned taking into account options in surgical training and education. 10.3205/cto000098