Clinical application of midpiece facial nerve dissection in regional parotidectomy / 华西口腔医学杂志

OBJECTIVE@#To propose and evaluate the clinical effect of midpiece facial nerve dissection through transparotid approach in regional parotidectomy.@*METHODS@#A total of 136 patients with benign parotid tumors were categorized into three groups according to the way of facial nerve dissection: anterograde dissection from main trunk (anterograde, n=70), retrograde dissection from distal branches (retrograde, n=34), and midpiece dissection through transparotid approach (middle dissection, n=32). Surgery duration, facial nerve injury, salivary fistula, earlobe sensation, Frey's syndrome, and aesthetic evaluation were compared.@*RESULTS@#The surgery duration in the middle dissection group was significantly shorter than that in the other two groups. The proportion of salivary fistula was higher in the anterograde group (9 cases, 12.9%; P<0.05) compared with that in the other groups. Postoperative facial nerve injury was similar between the middle dissection (1 case, 3.1%) and anterograde groups (3 cases, 4.3%) with lower injury rate compared with the retrograde group (7 cases, 20.6%). The anterograde group had more cases of hypoesthesia of the earlobe (12 cases, 17.1%; P<0.05) than the other two groups. Aesthetic score was higher in the anterograde and middle dissection groups compared with that in the retrograde group (P<0.05).@*CONCLUSIONS@#Midpiece facial nerve dissection is technically feasible and clinically viable in regional parotidectomy.

Comparison of 127° small and 135° large stem angle prostheses in total hip arthroplasty / 中国骨伤

OBJECTIVE@#To investigate the effect of total hip arthroplasty(THA) with the prosthesis of 127° small neck stem angle and 135° large neck stem angle.@*METHODS@#From January 2014 to June 2016, 84 patients with THA were selected, including 44 males and 40 females, aged 45 to 72(53.4±8.1) years old, 68 patients with necrosis of the femoral head(32 on the left and 36 on the right), 16 patients with serious osteoarthritis of the hip caused by other reasons, and the course of disease was 9 to 36 (24.0±5.5) months. Forty-two patients in each group were evaluated by Harris score, visual analog score(VAS), length measurement of lower limbs, biomechanical evaluation of different angles of the neck stem. The complications and quality of life 24 months after operation were compared.@*RESULTS@#Two patients in each group were lost, the rest were followed up for 30 to 36 (33.0±1.6)months. The Harris score and the length of both lower limbs were measured before and 1, 6, 12, 24 months after operation. The difference of Harris score and the length of both lower limbs in the two groups was significantly improved compared with that before operation(@*CONCLUSION@#THA with large and small neck stem angle prosthesis can better recover the function of hip joint, but large neck stem angle can reduce the degree of postoperative pain and improve the quality of life of patients.

A study on the dimensional error of 3D printing maxilla models / 重庆医学

Objective To measure the dimensional error of three dimensional printing maxilla models for the clinical application to oral and maxillofacial surgery.Methods The FDM 3D printing was employed to make standard geometric shape models and maxillary models.After the surface finish of both models being observed,the contour data and fineness of geometric models,as well as the distance error of bony markers between maxillary models and jaw bones specimen were measured.Results Within the 3D printing standard geometric model,the fiber arrange horizontally in X-Z,Y-Z surface and crosswise in X-Y surface,and the accuracy errors range from-1.67％ to 1.47％.Moreover,the maximum resolution was 0.25 mm in X and Y axis,and 0.50 mm in Z axis.Within the maxillary model,the distance error of bony markers range from-0.08 ％ to 1.96 ％,and the mean errors were 1.59 ％,0.86％,0.42％ in X,Y and Z axis respectively.The mean error in X axis was significantly larger than that in Y or Z axis (P＜0.05).Conclusion 3D printing maxilla models may possess high accuracy and apply to clinical practice.

Experimental study on establishment of a 3D finite element model of human craniomaxillofacial region and its use in impact injury simulation / 中华创伤杂志

Objective To develop a 3D finite element model for the human craniomaxillofacial region in an attempt to offer basis to the research of simulation of craniomaxillofacial injury.Methods A healthy adult male was submitted to head CT scan, and the data was imported into the Mimics 15.0 software for threshold segmentation and 3D reconstruction according to the classifications of bone tissue, skin tissue and subcutaneous tissue.The reconstruction data was imported into 3D reverse software Geomagic Studio 2012, and the images were optimized and the 3D model was generated.The three parts of the model were fitted according to the actual proportion using the 3D control software Solidworks 14.0, and then the boundary conditions were derived.Hypermesh 12.0 finite element processing software was used to build the volume mesh, and the model was established.Each layer of the model was given to the material parameters, and the simulation conditions were provided to test the model.Results This model was completely composed of volume meshes, including 214,250 hexahedral meshes and 411,920 nodes.This model can clearly show the stress distribution, the trend of fracture line, the displacement of fracture block of soft and hard tissue during the simulation, and the results are consistent with clinical practice.Conclusion A three-dimentional finite element model with good performance is established, which can be used for biomechamics simulation analysis of multiple sites on the head or the whole structure, and has a certain significance in clinical and scientific research.

Biomechanical study on the impact injure of human mandible by finite element method / 实用口腔医学杂志

Objective:To investigate biomechanical changes of mandible in the impact injure simulated by finite element method (FEM).Methods:Mimics and Comsol software were used to build a FEM of human craniofacial bone based on CT scan data of a normal adult.LS-DYNA and Hypermesh software were used to simulate the impact with different quality,velocity and angulation pro-duced injures of human mandible,the biomechanical parameters of the mandible in the impact injury process were analysed.Results:A FEMof human maxillofacial bone was established,and the dynamic process of different impact force produced damage was simula-ted.Mandibular chin,angle and condylar neck was the stress concentrated area in the process of mandible injury.There was higher stress peak at the site which was closer to the impact position,the stress peak arrival time was also earlier.When the impactor with the same quality,the bigger the velocity,the greater the stress peak.When the impactor with the same velocity,the bigger the quali-ty,the greater the stress peak.When the impactor with the same velocity and quality,there was greater stress peak under the impact to mandible from angulation of 0 degree.Stress transfered to the surrounding bone from the impact position radially and gradually re-duced.The bone area with small cross-section was prone to high stress and more serious damage.Conclusion:The quality,the ve-locity,the impact angle and the impact site are the factors affecting the severity of impact injury.

Application of lateral arm flap in the repair of oral and maxillofacial defects / 实用口腔医学杂志

Objective:To investigate the value of the lateral arm free flap (LAFF)in the repair of oral and maxillofacial defects af-ter resection of malignant tumor.Methods:22 cases received LAFF from January 2012 to December 2012 were studied.The flap size,preparation time,vessel diameter,anastomosis time,survival situation,success rate and postoperative results were observed. Results:The flap ranged from 14 cm ×8 cm to 6 cm ×4 cm.All flaps survived well without vascular crisis.Repair results were satis-factory.Conclusion:LAFF,with constant anatomy and simple preparation,can be applied in the repair of oral and maxillofacial de-fects after tumor resection.