Analysis of vector alignment with the Zitelli bilobed flap for nasal defect repair: a comparison of flap dynamics in human cadavers.

Objective: To determine whether differences of angles between the alar rim and the long axis of the secondary defect in a Zitelli bilobed flap affect alar displacement in a fresh cadaver model.

Methods: In fresh cadaver heads, identical, unilateral 1-cm circular defects were created at the superior alar margin. Three different laterally based bilobed flap templates for reconstruction were used. One template, used on 3 cadavers, had an angle of 60 degrees between the alar rim and the long axis of the secondary defect. Another template, used on 3 cadavers, had an angle of 90 degrees . The last template had an angle of 135 degrees and was used on 2 cadavers. Photographs were taken before the repair and after with the camera and cadaver heads in the same spatial relationship to each other.

Results: In the 3 cadavers that had repair using an angle of 60 degrees , all cadavers experienced alar retraction, with a mean displacement of 1.3 mm. This was not a statistically significant change (P = .07). In the defects that had repair using an angle of 90 degrees , there was also no significant alar displacement (P = .72). In the 2 cadavers that underwent repair using an angle of 135 degrees , both ala underwent depression by 1.0 mm. When the differences achieved between the different angles were compared, there was a significant difference in measured distortion between the cadavers that had 90 degrees and 60 degrees vector placement (P = .02). There were no measurable changes to the contralateral maximal nostril distance.

Conclusions: Vector alignment can have an impact on nostril displacement. In bilobed flaps, the axis of the secondary defect may play an important role. This study suggests that secondary defects aligned perpendicular to the nostril have the least amount of alar distortion.