IRCT2014061013938N2 IRCT 2014-07-20 Investigation secretary of tabriz university of medical sciences effect of two different surgical techniques on amount of nasal mucosal tear Comparison of rate and severity of nasal mucosal tear with internal and external lateral nasal osteotomy using endoscope 2014-04-21 anticipated 30 Complete https://irct.ir/trial/13654 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Prevention. N/A nasal mucosal tear. Intervention 1: intervention group: after induction of general anesthesia and injection of 10 cc of 1:200000 epinephrine solution at lateral nasal walls and nasal dorsum the surgery was began,3mm osteotome without guard was introduced through skin at the midway between inner canthus and vestibule. when the cutting edge of osteotome reached bone the external osteotomy was initiated . In a blinded manner, another investigator used nasal endoscopy to detect nasal mucosal tears and reported them in millimeter (mm). Intervention 2: control group: after induction of general anesthesia and injection of 10 cc of 1:200000 epinephrine solution at lateral nasal walls and nasal dorsum the surgery was began. mucosal incision was made at the lateral nasal wall just above the junction of inferior turbinate.after introduction of 3mm guarded osteotome the internal osteotomy was initiated and completed at the level of the inner canthus . In a blinded manner, another investigator used nasal endoscopy to detect nasal mucosal tears and reported them in millimeter (mm).