Displacement and stress distribution of the craniomaxillofacial complex under different surgical conditions: a three-dimensional finite element analysis of fracture mechanics

Objective To provide a simplified treatment strategy for patients with maxillary transverse deficiency. We investigated and compared the fracture mechanics and stress distribution of a midline palatal suture under dynamic loads during surgically-assisted rapid palatal expansion. Methods Based on the cone-beam computed tomography (CBCT) data of a 21-year-old female volunteer, a three-dimensional model of the cranio-maxillofacial complex (including the palatal suture) was constructed. A finite element analysis model was constructed based on meshwork. After the yield strength of the palatal suture was set, an increasing expansion force (0–500 N) was applied within 140 ms to calculate the time–load curve, which mimicked nonsurgical bone expansion (model A). The same method was used to evaluate the fracture process, time and stress distribution of the palatal suture in maxillary lateral osteotomy-assisted (model B) and LeFort osteomy I (LFIO)-assisted expansion of the maxillary arch (model C). Results Compared with model A, the palatal suture of model B and model C showed a faster stress accumulation rate and shorter fracture time, and the fracture time of model B and model C was almost identical. Compared with model A, we discovered that model B and model C showed greater lateral extension of the maxilla, and the difference was reflected mainly in the lower part of the maxilla, and there was no difference between model B and model C in lateral extension of the maxilla. Conclusions Compared with arch expansion using nonsurgical assistance (model A), arch expansion using maxillary lateral wall-osteotomy (model B) or LFIO had a faster rate of stress accumulation, shorter time of fracture of the palatal suture and increased lateral displacement of the maxilla. Compared with arch expansion using LFIO (model C), arch expansion using lateral osteotomy (model B) had a similar duration of palatal suture rupture and lateral maxillary extension. In view of the trauma and serious complications associated with LFIO, maxillary lateral wall-osteotomy could be considered a substitute for LFIO.

Displacement and Stress Distribution of the Craniomaxillofacial Complex Under Different Surgical Conditions: A Three-Dimensional Finite Element Analysis of Fracture Mechanics

Objective: To provide a simplified treatment strategy for patients with maxillary transverse deficiency. We investigated and compared the fracture mechanics and stress distribution of a midline palatal suture under dynamic loads during surgically-assisted rapid palatal expansion. Methods: Based on the cone-beam computed tomography (CBCT) data of a 21-year-old female volunteer, a three-dimensional model of the cranio-maxillofacial complex (including the palatal suture) was constructed. A finite element analysis model was constructed based on meshwork. After the yield strength of the palatal suture was set, an increasing expansion force (0–500 N) was applied within 140 ms to calculate the time–load curve, which mimicked nonsurgical bone expansion (model A). The same method was used to evaluate the fracture process, time and stress distribution of the palatal suture in maxillary lateral osteotomy-assisted (model B) and LeFort osteomy I (LFIO)-assisted expansion of the maxillary arch (model C). Results: Compared with model A, the palatal suture of model B and model C showed a faster stress accumulation rate and shorter fracture time, and the fracture time of model B and model C was almost identical. Compared with model A, we discovered that model B and model C showed greater lateral extension of the maxilla, and the difference was reflected mainly in the lower part of the maxilla, and there was no difference between model B and model C in lateral extension of the maxilla. Conclusions: Compared with arch expansion using nonsurgical assistance (model A), arch expansion using maxillary lateral wall-osteotomy (model B) or LFIO had a faster rate of stress accumulation, shorter time of fracture of the palatal suture and increased lateral displacement of the maxilla. Compared with arch expansion using LFIO (model C), arch expansion using lateral osteotomy (model B) had a similar duration of palatal suture rupture and lateral maxillary extension. In view of the trauma and serious complications associated with LFIO, maxillary lateral wall-osteotomy could be considered a substitute for LFIO.

The Impact of Surgical Procedures During Septorhinoplasty on the Intraoperative Pain Response

Background During septorhinoplasty, many different surgical procedures are used to bring the nose to the desired shape and to solve the breathing complaints. As a matter of course, intraoperative pain response occurs due to these procedures. Objectives This study aims to evaluate the intraoperative pain formed during septorhinoplasty surgery with numerical values, and to determine which stage of surgery is more painful. Methods Between April 2019 and March 2020, a total of 30 female patients who were planned to undergo septorhinoplasty were included in this prospective study. Standard anesthesia and analgesia were applied to all patients. During surgery, State Entropy (SE) measure was used to evaluate the depth of anesthesia, and Surgical Pleth Index (SPI) was used to evaluate the response of the central nervous system to pain "Nociception". Results The age of the patients ranged from 18-42-years-old (average, 25.3 ± 6.1 years). The average value of State Entropy (SE) recorded during the surgery for all patients was found to be 45.43 ± 5.37. The mean beginning SPI value recoded from all of the patients was found to be 23.4 ± 8.84, when compared with the beginning value; the values recorded during periost dissection, lateral osteotomy and lower turbinate lateralization were statistically significantly higher (P <0.005). Conclusions Although sufficient depth of anesthesia and standard protocol of analgesia were applied, pain response was found to be significantly higher at some procedures during septorhinoplasty. We think that increasing the depth of anesthesia during these procedures will increase the comfort of this operation by inhibiting pain response.