Clinical analysis in 45 cases of extensive intraductal carcinoma treated by breast shape reserving surgery with vertical double-pedicle bridge / 中国实用外科杂志

OBJECTIVE: To investigate the clinical effect of breast shape reserving surgery with vertical double dermal pedicle bridge in the treatment of extensive intraductal breast cancer.METHODS: During March 2015 to August 2017,the clinical and follow-up data of 45 patients with extensive intraductal cancer accepting breast shape reserving surgery with vertical double-pedicle bridge in Shengjing Hospital of China Medical University were analyzed retrospectively.RESULTS: Among the 45 cases,35 were treated with the modified McKissock mammaplasty technique and 10 combined prosthesis.The median follow-up time was 40(24-48) months.The disease-free survival rate was 100%.Two patients with nipple necrosis after combined prosthesis implantation recovered within 6 months after treatment.CONCLUSION: In the treatment of extensive intraductal breast cancer,the use of vertical double-pedicle dermal bridge for breast shape reserving(with or without prosthesis) has a satisfied efficacy.

2D/3D registration system based on single X ray image and CT data / 医用生物力学

Objective To build a 2D/3D registration system based on the compute unified device architecture(CUDA) frame with single X-ray image and CT data of knee joints and apply it in the research of knee motion and stability of implanted prosthesis. Method The digital radiography(DR) equipment used in the study was calibrated by the Zhang zhengyou Calibration Method, and then digitally rendered radiographs(DRR) images were generated in the CUDA frame with light tracing algorithm, and the best 2D/3D registration parameters were calculated with a similarity operator of cross correlation; finally, the results were evaluated by using the method of 3D/3D registration with data obtained from a 3D laser scanner. Results With knee specimen X-ray images and CT data, in 6 degrees of freedom, the average errors of transform were below 1 mm, and those of rotation were below 1°. Conclusions The 2D/3D registration system can meet the precision requirement of motion detection and be used to study the knee motion and prosthesis location.

Impact of muscle strength on knee joint stability in static loading / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the in vivo stability of normal and anterior cruciate ligament (ACL)-injured knee joint before and after epidural anesthesia under 134 N pre-loading and evaluate the influence of muscular tension on the knee stability.</p><p><b>METHODS</b>Eight volunteers with unilateral ACL rupture and normal contralateral knee were enrolled in this study. CT (3D) images and 2 orthogonal images of the knee were captured at 0°, 30°, 60°, and 90° under 134 N pre-loading. The orthogonal images were used to recreate the in vivo knee positions at each of the targeted flexion angles by 2D/3D registration to analyze the tibial translation data.</p><p><b>RESULTS</b>The anterior tibia translation of both the intact and ACL-injured knees after anesthesia was significantly different from that before anesthesia at all the angles (P<0.05). The anterior tibial translation of the intact knee after anesthesia increased by 1.7 mm at 0°, 2.7 mm at 30°, 2.6 mm at 60°, and 2.3 mm at 90°, as compare to the increase of ACL-injured knee by 4.2 mm, 2.6 mm, 1.2 mm, and 1.6 mm, respectively.</p><p><b>CONCLUSION</b>The muscular tension has evident influence on the knee stability in static loading.</p>

Biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the effect of biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing.</p><p><b>METHODS</b>Thirty patients undergoing hip resurfacing arthroplasties were enrolled in this study. The clinical outcomes of the patients were assessed according to the Harris Hip Score before and after the surgery, X-ray examinations and biomechanical reconstruction evaluations.</p><p><b>RESULTS</b>After the operation, the length of the patients' legs was shortened by a mean of 2.4 mm. and the femoral offset was decreased by a mean of 5.45 mm. No dislocation were be found in these patients. The preoperative Harris Hip Score was 36.69-/+7.16, significantly lower than that postoperative score (89.63-/+3.36, P<0.01).</p><p><b>CONCLUSION</b>Precise biomechanical reconstruction of the hip can be achieved in hip resurfacing arthroplasty, and the stability and functional restoration is guaranteed by large diameter prosthesis design.</p>

Finite element analysis of the biomechanics of human mandible in response to impact force / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the biomechanical mechanism of impact force-induced mandibular fractures and its finite element analysis.</p><p><b>METHODS</b>Three mandibular impact fracture models were prepared using intact human mandibular specimens and simulated maxillary models according to the Hanau principle of articulator and a MTS-858 biological material testing machine. Mandibular impact was delivered in the direction of the chin level at the mandibular postural position (MPP) on MTS. The computerized mandibular model was then established from 3-dimensional laser scanning images for finite element analysis using ANSYS7.0.</p><p><b>RESULTS</b>The 3 mandibular specimens were fractured at the chin, where the maximum force was 2151.10-/+ 125.18 N with response time of 17.3-/+2.3 ms. Impact simulation with ANSYS mimicking stress changes in the internal jaw suggested the chin as place where maximum stress occurred. According to the stress curve, the maximum stress of 3201.35 kPa occurred at the point 1.92 cm from the upper edge of the chin.</p><p><b>CONCLUSION</b>The combination of mandibular impact experiments and finite element analysis allows quantification of several parameters of the jaw and provides clues for understanding the biomechanical mechanism of mandibular impact fractures.</p>

Measurement of the vertebral pedicle in children / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain the spinal anatomic data of children for the development of implants used for scoliosis correction in children.</p><p><b>METHODS</b>Twelve children cadaver spines (C(3)-L(5)) were separated into single vertebrae after CT scanning of the specimens. The transverse and sagittal pedicle length, transverse and sagittal pedicle angle, pedicle length versus spinal level were measured with either electronic vernier caliper or on reconstructed 3D model of the spine.</p><p><b>RESULTS</b>The transverse pedicle length, sagittal pedicle length, transverse pedicle angle, sagittal pedicle angle and pedicle length were significantly different among cervical, thoracic and lumbar groups, and these data suggest significant differences of children's pedicle from the documented adult spine data.</p><p><b>CONCLUSION</b>The measurement can provide basic anatomic data for the development of the implant for scoliosis correction in children.</p>

Establishment of a testing system of three-dimensional spinal kinematics in vivo based on two- and three-dimensional image registration / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the feasibility of using two- and three-dimensional (2D/3D) image registration for establishing a testing system of 3D kinematics of the spine in vivo.</p><p><b>METHODS</b>CT data of the adult human lumbar spine were collected and the two orthogonal images of the same specimen were captured using an X-ray fluoroscope at two different positions. The 3D computer models of L3 and L4 vertebrae were reconstructed. A virtual fluoroscope was then created with solid modeling software to reproduce the relative positions of the orthogonal images. Two virtual cameras in the software were used to represent the X-ray sources. The 3D computer models of the L3 and L4 vertebrae were then introduced into the virtual fluoroscope respectively and projected onto the orthogonal images by the two virtual cameras. By matching the projections of the 3D model to the orthogonal images of L3 and L4 vertebrae, the 3D positions of L3 and L4 were obtained. After calculation, the relative displacement and angle of L3 were determined.</p><p><b>RESULTS</b>After 2D/3D image registration, the relative displacement and angle were calculated. Compared with position I, the positional changes of L3 were represented with an extension of 5.86 degrees, left bending of 1.85 degrees and right rotation of 2.96 degrees.</p><p><b>CONCLUSION</b>2D/3D image registration allows the simulation of 3D kinematics of the spine in vivo, but the efficiency and accuracy of this technique need further evaluation.</p>

The effect of disc degeneration on the structural property distributions in the cervical vertebral endplates / 中华外科杂志

<p><b>OBJECTIVE</b>To study the effect of disc degeneration on the structural property distributions in the cervical vertebral endplates.</p><p><b>METHODS</b>A 2 mm-diameter hemispherical indenter was used to perform indentation tests at 0.03 mm/s to the depth of 2 mm at 20 normalized locations in 50 bony endplates of intact human cervical vertebrae (C2 approximately C7). The resulting load-displacement curves were used to extract the failure load and stiffness of each test site. Grade of disc degeneration was determined using Nachemson's grading scale. One-way ANOVA, factorial analyses, SNK tests and correlate analyses were used to analyze the result data.</p><p><b>RESULTS</b>Both the failure load and stiffness decreased with disc degeneration in the cervical endplates (P <0.001, both), and correlated significantly with the disc degeneration (rs=-0.429 and rs=-0.244, respectively). Only the distribution of superior cervical endplate changed with disc degeneration, but that of inferior cervical endplate changed little.</p><p><b>CONCLUSIONS</b>The structural property distributions in the cervical vertebral endplates change significantly in the degenerated discs. It suggests that disc degeneration is an important factor to evaluate the intervertebral implant subsidence in anterior cervical fusion.</p>