Objective To study the feasibility of virtual intercondylar notchplasty by applying MRI two-dimensional (2D) images to reconstruct three-dimensional (3D) images and measure the size of intercondylar notch. Methods Thirty healthy volunteers who had no knee joint disease and surgery history were selected. There were 15 females and 15 males with an age range of 20-30 years, weight range of 45-74 kg, and height range of 150-185 cm. They were divided into male group and female group, and the knees of each group were divided into 2 subgroups (the left group and right group). MRI scan of the left and right knees was performed, and the 2D images of MRI were imported into Mimics10.01 medical image control system for 3D reconstruction. The related anatomical data as follows were measured from the 3D digital model and analyzed by statistical software: notch width (NW), condylar width (CW), and notch width index (NWI). Then the 3D knee images of patients with anterior cruciate ligament (ACL) injury were collected between January and March 2010, and 4 patients with narrow intercondylar notch (NWI≤0.2) were selected for reconstructing the 3D model of the knee and simulating the intercondylar notch plasty. Then, the volume of osteotomy in 3D model was calculated and applied in the ACL reconstruction surgery, and whether the graft had impingement with intercondylar notch or not was evaluated. Results There were significant differences in NW and CW between male group and female group (P≤lt;≤0.05), but no significant difference was found in the NWI (P≤gt;≤0.05). And there was no significant difference in NW, CW, and NWI between the left and right knees both in male group and female group (P≤gt;≤0.05). After ACL reconstruction and intercondylar notchplasty, the shape of intercondylar notch became normal (NWI≤gt;≤0.22), no impingement occurred between the graft and intercondylar notch under arthroscopy within 3-month follow-up. Conclusion The shape of intercondylar notch of 3D model based on MRI 2D images is similar to the real intercondylar notch. NWI is one of important indexes which can reflect the narrow level of intercondylar notch. The virtual intercondylar notchplasty may provide preoperative plan and guidence for ACL reconstruction operation to avoid the impingement between graft and intercondylar notch after surgery.
Objective To study digitize design of custom-made radial head prosthesis and to verify its matching precision by the surgery of preoperative three-dimensional (3-D) virtual replacement. Methods Six healthy adult volunteers (3 males and 3 females, aged 25-55 years with an average of 33 years) received slice scan of bilateral elbow by Speed Light 16-slice spiral CT. The CT Dicom data were imported into Mimics 10.0 software individually for 3-D reconstruction image, and the left proximal radial 3-D image was extracted, the mirror of the image was generated and it was split into 2 pieces: the head and the neck. The internal diameter and the length of the radial neck were obtained by Mimics 10.0 software measurement tools. In Geomagic Studio 12 software, the radial head was simulated to cover the cartilage surface (1 mm thickness) and generated to an entity. In UG NX 8.0 software, the stem of prosthesis was designed according to the parameters above and assembled head entity. Each custom-made prosthesis was performed and verified its matching precision by the surgery of preoperative 3-D virtual replacement. Results Comparing the morphology of 6 digitize custom-made prostheses with ipsilateral radial heads by the 3-D virtual surgery, the error was less than 1 mm. The radial head prosthesis design on basis of the contralateral anatomy was verified excellent matching. Conclusion The 3-D virtual surgery test and the digitized custom-made radial head prosthesis will be available for clinical accurate replacement.
ObjectiveTo analyze intrahepatic vascular structures, divide liver segment automatically, and carry out virtual anatomic hepatectomy for virtual liver surgery planning based on liver threedimensional images. MethodsThe branches of portal vein were labeled in the level of segment based on spiral CT scanning images by using the liver surgery planning system software Liv 1.0. Thus, the simulation of an anatomical resection could be carried out. ResultsAccording to the portal segment branches, each individual liver segment could be divided automatically. The three-dimensional liver model was reconstructed based on liver segments, and the margin of liver segments was displayed clearly. On that basis, the simulation of anatomical resection and the volumetric estimation could be performed. ConclusionsThe three-dimensional liver model with intrahepatic vessel is reconstructed clearly, automatic segmentation of liver segment, the simulation of anatomical resection, and volumetric estimation can be applied in succession. The planning can be accomplished with Liv 1.0 on personal computer by the user, which provides a software platform for clinical application of virtual liver techniques.
Objective To investigate the significance of three dimensional (3D) visualization and virtual surgery system in liver transplantation surgery. Methods Two patients suffered from cholangiolithiasis were scanned by 64 slice helical-CT on livers and the data were collected. Man-made segmentation and true up on the image from the data were carried out. 3D moulds of the liver and the intrahepatic vessels were reconstructed by VTK software respectively. And then, the moulds were imported to the FreeForm Modeling System for modifying. At last, auxiliary partial orthotopic liver transplantation was simulated with the force-feedback equipment (PHANTOM). Results ①It had greatly verisimilar image for the reconstructed 3D liver moulds with artery, vein, portal vein and bile duct; By liver seeing through, it had high fidelity and b 3D effect for the intrahepatic artery, vein, portal vein and bile duct, and their spatial disposition and course and correlationship were shown clearly. ②In the virtual surgery system, the virtual scalpel could be manipulated on 3D liver mould with PHANTOM. The simulating effect was the same as the clinic operation for auxiliary partial orthotopic liver transplantation. Plane visualization of hepatic resection and intrahepatic vessel cutting was achieved by adjusting the transparency of the resection part. Life-like could be felt and power feeling could be touched during virtul operation. Conclusion ①The visualized liver mould reconstructed is 3D and verisimilar, and it is helpful to design reasonable scheme for liver transplantation. ②It not only can improve the surgical effect and decrease the surgical risk, but also can reduce the complications and enhance the communication between doctor and patient through designing surgical plan and demonstrating visualized operation before surgery. ③Visualized liver transplantation surgery is helpful for medical workers to train and study.