Virtual Reality and Three-Dimensional Printed Models Improve the Morphological Understanding in Learning Mandibular Sagittal Split Ramus Osteotomy: A Randomized Controlled Study

Background: The mandibular sagittal split ramus osteotomy (SSRO) is a routine operation performed to correct mandibular deformity including mandibular retrusion, protrusion, deficiency, and asymmetry. The SSRO remains a challenging procedure for junior surgeons due to a lack of adequate morphological knowledge necessary for success in clinical practice. Virtual reality (VR) and three-dimensional printed (3DP) models have been widely applied in anatomy education. The present randomized, controlled study was performed to evaluate the effect of traditional educational instruments, VR models, and 3DP models on junior surgeons learning the morphological information required to perform SSRO.Methods: Eighty-one participants were randomly assigned to three learning groups: Control, VR, and 3DP. Objective and subjective tests were used to evaluate the learning effectiveness of each learning instrument. In the objective test, participants were asked to identify 10 anatomical landmarks on normal and deformed models, draw the osteotomy line, and determine the description of SSRO. In the subjective test, participants were asked to provide feedback regarding their subjective feelings about the learning instrument used in their group.Results: The objective test results showed that the VR and 3DP groups achieved better accuracy in drawing the osteotomy line (p = 0.027) and determining the description of SSRO (p = 0.023) than the Control group. However, there was no significant difference among the three groups regarding the identification of anatomical landmarks. The VR and 3DP groups gave satisfactory subjective feedback about the usefulness in learning, good presentation, and enjoyment. The Control and 3DP groups reported positive feelings about ease of use.Conclusion: The current findings suggest that VR and 3DP models were effective instruments that assisted in the morphological understanding of SSRO-related anatomical structures. Furthermore, 3DP models may be a promising supplementary instrument to bridge the gap between conventional learning and clinical practice.

The Validity and Accuracy of 3D-printed Patient-specific Instruments for High Tibial Osteotomy: A Cadaveric Study

Objective High tibial osteotomy (HTO) has been used for the treatment of patients with knee osteoarthritis. However, the successful implementation of HTO requires precise intraoperative positioning, which places greater requirements on the surgeon. In this study, we aimed to design a new kind of 3D-printed patient-specific instrument (PSI) for HTO, including a positioning device and an angle bracing spacer, and verify its effectiveness using cadaveric specimens.Methods This study included ten fresh human lower limb cadaveric specimens. Computed Tomography(CT) and X-ray examinations were performed to make preoperative plans. PSI was designed and 3D-printed according to the preoperative plan. Then, the PSI was used to guide HTO. Finally, we performed X-ray and CT after the operation to verify its validity and accuracy.Results The PSI use process was adjusted according to the pre-experimental procedure in 1 case. Hinge fracture occurred in 1 case. According to X-rays of the remaining 8 cadaveric specimens, no statistically significant difference was noted between the preoperative planning medial proximal tibial angle (MPTA) and postoperative MPTA (P > 0.05) or the preoperative and postoperative posterior slope angle (PSA) (P > 0.05). According to the CT of 10 cadaveric specimens, no statistically significant difference was noted between the design angle and actual angle, which was measured according to the angle between the osteotomized line and the cross-section (P > 0.05). The gap between the designed osteotomy line and the actual osteotomy line was 2.09(0.8~3.44) mm in the coronal plane and 1.58(0.7~2.85) mm in the sagittal plane.Conclusion This 3D-printed PSI of HTO accurately achieves the angle and position of the preoperative plan without increasing the stripping area. However, its use still requires a certain degree of proficiency to avoid complications, such as hinge fracture.

Effect of the Osteotomy Inclination Angle in the Sagittal Plane on the Posterior Tibial Slope of the Tibiofemoral Joint in Medial Open-Wedge High Tibial Osteotomy: Three-Dimensional Computed Tomography Analysis

The posterior tibial slope of the tibiofemoral joint changes after medial open wedge high tibial osteotomy (MOWHTO), but little is known about the effect of the sagittal osteotomy inclination angle on the change in the posterior tibial slope of the tibiofemoral joint. The purpose of this study was to investigate the effect of the osteotomy inclination angle in the sagittal plane on changes in the posterior tibial slope after MOWHTO by comparing how anterior and posterior inclination affect the posterior tibial slope of the tibiofemoral joint. The correlation between the osteotomy inclination angle and the postoperative posterior tibial slope angle was also assessed. Between May 2011 and November 2017, 80 patients with medial compartment osteoarthritis who underwent MOWHTO were included. The patients were divided into two groups according to the sagittal osteotomy inclination angle on the 3D reconstructed model. Patients with an osteotomy line inclined anteriorly to the medial tibial plateau line were classified into group A (58 patients). Patients with posteriorly inclined osteotomy line were classified as group P (22 patients). In the 3D reconstructed model, the preoperative and postoperative posterior tibial slope, osteotomy inclination angle relative to medial tibial plateau line in sagittal plane, and gap distance and ratio of the anterior and posterior osteotomy openings were measured. The preoperative and postoperative hip-knee-ankle angle, weight-bearing line ratio, and posterior tibial slope were also measured using plain radiographs. In the 3D reconstructed model, the postoperative posterior tibial slope significantly increased in group A (preoperative value = 9.7 ± 2.9°, postoperative value = 10.7 ± 3.0°, p < 0.001) and decreased in group P (preoperative value = 8.7 ± 2.7°, postoperative value = 7.7 ± 2.7°, p < 0.001). The postoperative posterior tibial slope (group A = 10.7 ± 3.0°, group P = 7.7 ± 2.7°, p < 0.001) and posterior tibial slope change before and after surgery (group A = 1.0 ± 0.8°, group P = −0.9 ± 0.8°, p < 0.001) also differed significantly between the groups. The Pearson correlation coefficient was 0.875 (p < 0.001) for the osteotomy inclination angle, and multivariate regression analysis showed that the only significant factor among the variables was the sagittal osteotomy inclination angle (β coefficient = 0.216, p < 0.001). The posterior tibial slope changed according to the osteotomy inclination angle in the sagittal plane after MOWHTO. The postoperative posterior tibial slope tended to increase when the osteotomy line was inclined anteriorly with respect to the medial tibial plateau line but decreased when the osteotomy line was inclined posteriorly. To avoid inadvertent change of posterior tibial slope, close attention needs to be paid to maintaining the sagittal osteotomy line parallel to the medial joint line during MOWHTO.

Computed Tomography Analysis of Nasal Anatomy in Dorsal Preservation Rhinoplasty

Background Subdorsal septal resection and radix osteotomy are distinctive surgical steps in preservation rhinoplasty. Objectives The aim of this study was to evaluate the nasal bone thickness, the level of the septal bony-cartilaginous junction (K area), and the distances of the frontal sinus and skull base from the transverse osteotomy line in the Turkish population by means of conventional computed tomography (CT). Methods A retrospective evaluation was made of 203 consecutive preoperative paranasal CT scans of patients (classified in terms of age and gender) who had undergone rhinoplasty surgery between January 2020 and June 2021. The nasal bone thickness at the medial canthus level, and the distances between the transverse osteotomy line and the K area, the frontal sinus, and the cribriform plate were measured. Results The mean measurements were similar in terms of age groups (P = 0.402, P = 0.542, P = 0.134 and P = 0.276 for ages 18-30, 30-40, 40-50, and &gt;50 years, respectively). The mean nasal bone thickness and the distance between the transverse osteotomy line and the K area showed statistical significance (P = 0.001 and P = 0.001, respectively). In both genders, the mean distances between the transverse osteotomy line and the frontal sinus and the cribriform plate were similar (P = 0.921 and P = 0.280, respectively). The nasal bone was thinner and the K area position more cephalic in females. Conclusions CT plays an important role in preoperative planning. The need for resection of the ethmoid perpendicular bone may be greater in males when lowering the dorsal hump, and hence they may be more prone to skull base complications. It is therefore necessary to be more careful in the surgical stage of subdorsal septal excision in males.

A Rare Case of an Iliac Fracture at the Iliac Fossa Immediately after Salter Innominate Osteotomy

This report presents the unusual case of a 5-year-old girl with iliac fracture just after Salter innominate osteotomy for developmental dysplasia of the hip. The iliac fracture was diagnosed two days after Salter innominate osteotomy, and computed tomography (CT) revealed that it was at the extremely thin portion of the iliac wing called the “iliac fossa.” We were able to reduce the fracture by pulling the left leg distally, and after reducing the iliac bone, the ilium was fixed by Kirschner wire from the anteroinferior iliac spine and anterosuperior iliac spine. The patient was in a hip-spica cast for 6 weeks postoperatively and allowed to walk from 3 months after the surgery. At the last follow-up one year after the surgery, bone union was completely obtained, and she had no complications. The cause of the fracture seems to be the stress concentration on the iliac fossa due to the cranked iliac osteotomy line passing through the iliac fossa. The current case indicates the importance of careful evaluation by CT before surgery and ensuring that the osteotomy line does not extend near the iliac fossa.

Is angular artery trauma seen frequently in lateral osteotomy and responsible for peri-orbital ecchymosis?

ObjectiveThis study was performed on fresh frozen cadavers to investigate the role of angular artery damage.MethodsLateral osteotomies (‘high-low-high’ method) were carried out bilaterally, with a 4 mm guarded lateral osteotome, after the creation of a subperiosteal tunnel. Following completion of the lateral osteotomy, a skin incision was made in the midline dorsum. The dermis and subcutaneous tissues were carefully dissected, taking care not to damage the angular artery. Overlying tissues were cut and retracted to show the course of the angular artery.ResultsThe angular artery was not damaged in any of the cadavers. The angular artery was always lateral to the lateral osteotomy line.ConclusionThe high-low-high lateral osteotomy does not damage or traumatise the angular artery. The ecchymosis and oedema are related to other factors.

Evaluation of Lefort I Osteotomy Line and Pterygomaxillary Junction Region in Patients With Cleft Lip and Palate

Objective: This study aimed to evaluate the Le Fort I osteotomy line and pterygomaxillary junction via cone-beam computed tomography in individuals with cleft lip and palate (CLP). Design: Retrospective study. Patients and Methods: The study included individuals older than 16 years with CLP, who were scheduled for repositioning of the maxilla by Le Fort I osteotomy, and those with class III malocclusion with maxillary hypoplasia, who were scheduled for Le Fort I osteotomy. The measurements made in the area of the cleft of individuals with CLP were compared with both the side with no cleft and those with class III malocclusion with maxillary hypoplasia. A total of 11 measurements were made on the axial section parallel to the Frankfurt Horizontal plane, corresponding to the lower 1/5 of the distance between the infraorbital foramen and the anterior nasal spine. Results: There were significant differences both in the comparisons made between the individuals with CLP and those without CLP in terms of the canal-anterior alveolar crest (G) and sinus-anterior alveolar crest (L) measurements ( P < .05). The mean measurement values showed that the measurement results were higher in individuals with CLP in general. Conclusion: In conclusion, we believe that there might be difficulties both in osteotomy and down fracture stages during Le Fort I osteotomies performed in individuals with CLP.

Effect of Location of Genioplasty Osteotomy Line on Hard- and Soft-Tissue Contour of the Chin and Related Complications

AIM: This study aimed to assess the effect of the location of the genioplasty osteotomy line on hard- and soft-tissue contour of the chin and the occurrence of irregularity in the inferior border of the mandible. METHODS: In this retrospective cohort study, 20 patients who had undergone osseous genioplasty were divided into two groups with (A) osteotomy line at the premolar site and (B) osteotomy line at the molar site and were evaluated for irregularity in the inferior border of the mandible. Assessments were made using lateral cephalometry, panoramic radiography, and clinical examinations. Patients were also asked about their level of satisfaction with the outcome. RESULTS: Radiographically, 70% of patients in Group A and 40% of those in Group B had an irregularity in the inferior border of the mandible (p > 0.05). Palpation revealed that 70% in Group A and 60% in Group B had an irregularity in the inferior border of the mandible (p > 0.05). Inspection revealed such irregularity in 80% of patients in Group A and 20% in Group B (p < 0.05). Overall, 60% in Group A and 90% in Group B were satisfied with the results of genioplasty and did not mention anything about the occurrence of this complication (p > 0.05). CONCLUSIONS: Genioplasty with an osteotomy line at the molar site (compared to premolar site) had a lower incidence of the irregularity of the inferior border of the mandible and yielded higher patient satisfaction with the outcome. PRACTICAL IMPLICATIONS: Irregularity in the inferior border of mandible following conventional genioplasty is a common finding on radiographic and clinical examinations.