Comparison of Two Methods for Presurgical Volumetric Evaluation of Alveolar Cleft Bone Defects Using Computer-Aided Engineering.

ABSTRACT: Precise volumetric evaluation of the alveolar cleft facilitates accurate preparation of bone substitutes and reduces donor site morbidity. This study investigates 2 advanced presurgical volumetric assessment methods that use computer-aided engineering (CAE) software. Preoperative computed tomography (CT) scans from 20 unilateral alveolar cleft patients undergoing secondary alveolar bone grafting (SABG) were analyzed by CAE software. Cleft defect volumes were calculated using the mirror-reversed technique and the subtraction method. The mirror-reversed technique determines defect volume by reversing the noncleft side to the cleft side. The subtraction method determines defect volume by subtracting a mask of the preoperative cleft from a mask generated after simulated cleft filling. The mean defect volumes and calculation times of the mirror-reversed technique (1.27 ±â€Š0.35 cm3; 11.80 ±â€Š1.79 seconds) and the subtractive method (1.23 ±â€Š0.32 cm3; 9.43 ±â€Š1.35 seconds) did not differ significantly. In Bland-Altman analysis the 2 methods were equivalent for alveolar cleft defect assessment. Both methods exhibited acceptable interobserver reliability, high precision, clinical convenience, time efficiency, and high reproducibility, and can serve as valuable tools for the planning and execution of SABG. The subtraction method has broader potential applicability and can simulate intraoperative bone grafting more effectively.

A Novel Method to Calculate the Volume of Alveolar Cleft Defect Before Surgery.

BACKGROUND: This study aimed to evaluate a novel subtractive method for the precise calculation of alveolar cleft defect volume before surgery using the three-dimensional imaging software Mimics. METHODS: Ten patients (3 female, 7 male, age range 8-12 years) with unilateral alveolar cleft were enrolled in the study. Preoperative helical computed tomography scans were performed for all patients. A new subtractive method was introduced to precisely calculate the alveolar cleft defect volume before surgery with the aid of Mimics. The DICOM data of every patient were processed using the subtractive method. Statistical analyses were performed using Pearson's correlation test and t test. RESULTS: The mean volume of the alveolar cleft defect was 1811.97 ±â€Š817.90 mm. The mean time spent to calculate an alveolar cleft defect volume was 60.60 ±â€Š11.67 minutes. The Pearson correlation test (r = 0.38, P = 0.279) indicated a poor correlation between alveolar cleft defect volume and calculation time. CONCLUSIONS: Preoperative knowledge of defect volume is crucial in alveolar cleft repair. Accurate estimation of graft volume in alveolar cleft patients can be performed using this new subtractive method. Compared with previous methods, this new subtractive method is time-saving and suitable for both unilateral and bilateral clefts. Surgeons can use this method to design a surgical plan for each patient before surgery within a short time, and with less cost.

Anatomical Characterization and Three-Dimensional Modeling of the Muscles at the Corner of the Mouth: An Iodine Staining Technique Based on Micro-Computed Tomography.

The anatomy of the modiolus and surrounding muscles is complicated and contributes to the morphology of the mouth corner. The authors used iodine staining and micro-computed tomography to observe the anatomy of the modiolus and surrounding muscles. Based on the micro-computed tomographic images and the three-dimensional model construction, the authors found that the muscle fibers in the modiolus were oriented continuously in the running direction of the muscle itself and that there were no chaotic clumps in the region of muscle fiber convergence. The pars marginalis of the orbicularis oris muscle connects with the deep buccinator muscle, which may account for how the pars marginalis fibers act to press the upper lip against the maxillary teeth or invert it closer to the oral cavity. These findings may be helpful for plastic surgeons who perform commissuroplasty.