Biomechanical analyses of common suspension sutures in primary cleft lip rhinoplasty

Background For a better understanding of common suspension sutures during primary cleft lip nasal rhinoplasty, the biomechanical consequences of those sutures need to be demonstrated. Methods A finite element model of the infant specimen was established. The closure of cleft lip and four different specific suspension sutures were simulated by loading different forces on the model: 1. F1 to simulate the suture fastening both medial crura together; 2. F2 to simulate the suture which sewed both medial crura and the non-cleft-side upper lateral cartilage together; 3. F3 to simulate the suture elevating the alar cartilage cranially; 4. F4 to simulate the suture elevating the alar cartilage superiorly. The deformation and stress distribution consequent to each maneuver were analyzed in details. Results The deviation of columella was restored through the closure of cleft lip. Different suspension sutures had different biomechanical effects on the nasal structure. All suspension sutures had the function on elevating the alar cartilage. F2 had no function on restoring the collapse of the nasal tip. The suture which fastened both medial crura together leaded to the lowest stress on the skin envelope. Conclusions Each suspension suture had its characteristics respectively. The simulation suggested that F1, the suture which fastened both medial crura, could be the most potential maneuver for cleft lip rhinoplasty because it can symmetrically restore the shape of the nose without incurring a significant increase in stress.