Prediction of 3-Dimensional Coverage Surface Area of the Femoral Head in Hip Dysplasia Through Conventional Computed Tomography.

Background: Assessment of 3-dimensional (3D) femoral head coverage is critical in evaluating, preoperative planning, and treating hip dysplasia.

Purpose: To (1) propose a mathematical model to establish 3D femoral head coverage using conventional computed tomography (CT), (2) determine the correlation of 2D parameters with 3D coverage, and (3) characterize the patterns of dysplasia based on 3D morphology.

Study Design: Cross-sectional study; Level of evidence, 3.

Navigated multiplanar osteotomies for spinal primary bone tumors.

Background: Establishing the proper diagnosis and rendering appropriate treatment of spinal primary bone tumors (SPBT) can result in definitive cures. Notably, malignant, or benign SPBT (i.e.

Total Temporomandibular Joint Replacement and Simultaneous Orthognathic Surgery Using Computer-Assisted Surgery.

Background: Disorders of the temporomandibular joint (TMJ) are frequent and are usually associated with other disorders of the facial skeleton. Surgery might be needed to correct TMJ anatomy and function and, in cases where pathologies coexist, a two-stage corrective surgery might be needed. However, the current fashion of single-stage procedures is feasible with the aid of new technologies such as computer-assisted surgery (CAS).

Computer-assisted surgery (CAS) in orthopedic oncology. Which were the indications, problems and results in our first consecutive 203 patients?

Aims: to review a group of patients with primary bone tumors treated with intraoperative navigation and analyze: (1) The technical problems; (2) Indications for Computer Assisted Surgery (CAS); (3) Oncological results; (4) Non oncological complications.

Materials And Methods: All patients from a single institution who had preoperative virtual planned for an oncological primary bone resection assisted with navigation between May 2010 and July 2017 were enrolled in the study (203 patients). The use of computer-assisted surgery (CAS) was classified according to the oncologic procedure performed: (1) intralesional resections, (2) en-block resections, and (3) en-block resections + navigated allograft reconstructions.

Virtual Planning and Allograft Preparation Guided by Navigation for Reconstructive Oncologic Surgery: A Technical Report.

Introduction: Advanced virtual simulators can be used to accurately detect the best allograft according to size and shape.

Step 1 Acquisition Of Medical Images: Obtain a multislice CT scan and a magnetic resonance imaging (MRI) scan preoperatively for each patient; however, if the time between the scans and the surgery is >1 month, consider repeating the MRI because the size of the tumor may have changed during that time.

Step 2 Select An Allograft Using Virtual Imaging To Optimize Size Matching:

Step 3 Plan And Outline The Tumor Margins On The Preoperative Imaging: Determine and outline the tumor margin on manually fused CT and MRI studies using the registration tool of the mediCAS planning software or equivalent (Materialise Mimics software.

Is Navigation-guided En Bloc Resection Advantageous Compared With Intralesional Curettage for Locally Aggressive Bone Tumors?

Background: The treatment of locally aggressive bone tumors is a balance between achieving local tumor control and surgical morbidity. Wide resection decreases the likelihood of local recurrence, although wide resection may result in more complications than would happen after curettage. Navigation-assisted surgery may allow more precise resection, perhaps making it possible to expand the procedure's indications and decrease the likelihood of recurrence; however, to our knowledge, comparative studies have not been performed.

What Is the Expected Learning Curve in Computer-assisted Navigation for Bone Tumor Resection?

Background: Computer navigation during surgery can help oncologic surgeons perform more accurate resections. However, some navigation studies suggest that this tool may result in unique intraoperative problems and increased surgical time. The degree to which these problems might diminish with experience-the learning curve-has not, to our knowledge, been evaluated for navigation-assisted tumor resections.

Techniques in surgical navigation of extremity tumors: state of the art.

Image-guided surgical navigation allows the orthopedic oncologist to perform adequate tumor resection based on fused images (CT, MRI, PET). Although surgical navigation was first performed in spine and pelvis, recent reports have described the use of this technique in bone tumors located in the extremities. In long bones, this technique has moved from localization or percutaneous resection of benign tumors to complex bone tumor resections and guided reconstructions (allograft or endoprostheses).

Accuracy of Chest Wall Tumor Resection Guided by Navigation: Experimental Model.

Difficulty in identification wall chest tumors lead to unnecessary wide resections. Optical navigation and preoperative virtual planning are assets for surgeries that require exactness and accuracy. These tools enable physicians to study real anatomy before surgery and to follow an established pathway during procedure ensuring effectiveness.

3D Printed Models and Navigation for Skull Base Surgery: Case Report and Virtual Validation.

In recent years, computer-assisted surgery tools have become more versatile. Having access to a 3D printed model expands the possibility for surgeons to practice with the particular anatomy of a patient before surgery and improve their skills. Optical navigation is capable of guiding a surgeon according to a previously defined plan.

Virtual Microscopy Large Slide Automated Acquisition: Error Analysis and Validation.

The aim of this work is to assess and analyze the discrepancies introduced in the reconstruction of an entire tumoral bone slice from multiple field acquisitions of a large microscopy slide. The reconstruction tends to preserve the original structural information and its error is estimated by comparing the reconstructed images of eight samples against single pictures of these samples. This comparison is held using the Structural Similarity index.

Transfer accuracy and precision scoring in planar bone cutting validated with ex vivo data.

The use of interactive surgical scenarios for virtual preoperative planning of osteotomies has increased in the last 5 years. As it has been reported by several authors, this technology has been used in tumor resection osteotomies, knee osteotomies, and spine surgery with good results. A digital three-dimensional preoperative plan makes possible to quantitatively evaluate the transfer process from the virtual plan to the anatomy of the patient.

Does intraoperative navigation assistance improve bone tumor resection and allograft reconstruction results?

Background: Bone tumor resections for limb salvage have become standard treatment. Recently, computer-assisted navigation has been introduced to improve the accuracy of joint arthroplasty and possible tumor resection surgery; however, like with any new technology, its benefits and limitations need to be characterized for surgeons to make informed decisions about whether to use it.

Questions/purposes: We wanted to (1) assess the technical problems associated with computer-assisted navigation; (2) assess the accuracy of the registration technique; (3) define the time required to perform a navigated resection in orthopedic oncology; and (4) the frequency of complications such as local recurrence, infection, nonunion, fracture, and articular collapse after tumor resection and bone reconstruction with allografts using intraoperative navigation assistance.

The principles and applications of fresh frozen allografts to bone and joint reconstruction.

Fresh frozen allograft reconstruction has been used for a long time in massive bone loss in orthopedic surgery. Allografts have the advantage of being biologic reconstructions, which gives them durability. Despite a greater number of complications in the short term, after 5 years these stabilize with high rates of survival after 10 years.

Bone tumor resection: analysis about 3D preoperative planning and navigation method using a virtual specimen.

The use of three-dimensional preoperative planning and bone tumor resection guided by navigation has increased in the last ten years. However, no study to date, as far as we know, has directly provided evidence of accuracy of this method. The objective of this study was to describe a method capable of determining the accuracy of osteotomies performed for tumor resection planned and guided by navigation.

Accuracy of 3-D planning and navigation in bone tumor resection.

Surgical precision in oncologic surgery is essential to achieve adequate margins in bone tumor resections. Three-dimensional preoperative planning and bone tumor resection by navigation have been introduced to orthopedic oncology in recent years. However, the accuracy of preoperative planning and navigation is unclear.

Three-dimensional virtual bone bank system workflow for structural bone allograft selection: a technical report.

Structural bone allograft has been used in bone defect reconstruction during the last fifty years with acceptable results. However, allograft selection methods were based on 2-dimensional templates using X-rays. Thanks to preoperative planning platforms, three-dimensional (3D) CT-derived bone models were used to define size and shape comparison between host and donor.

Multiplanar osteotomies guided by navigation in chondrosarcoma of the knee.

Surgical resection with adequate margins is the treatment of choice in chondrosarcoma. However, well-circumscribed lesions can be completely resected by performing multi-planar osteotomies guided by computer-assisted navigation. This type of resection had been recently described in select patients with sarcomas; however, these osteotomies are technically demanding to plan and perform intraoperatively.

Validity of an automatic measure protocol in distal femur for allograft selection from a three-dimensional virtual bone bank system.

Osteoarticular allograft is one possible treatment in wide surgical resections with large defects. Performing best osteoarticular allograft selection is of great relevance for optimal exploitation of the bone databank, good surgery outcome and patient's recovery. Current approaches are, however, very time consuming hindering these points in practice.

Automatic scan planning for magnetic resonance imaging of the knee joint.

Automatic scan planning for magnetic resonance imaging of the knee aims at defining an oriented bounding box around the knee joint from sparse scout images in order to choose the optimal field of view for the diagnostic images and limit acquisition time. We propose a fast and fully automatic method to perform this task based on the standard clinical scout imaging protocol. The method is based on sequential Chamfer matching of 2D scout feature images with a three-dimensional mean model of femur and tibia.

Minimization of intra-operative shaping of orthopaedic fixation plates: a population-based design.

In this paper we present a new population-based method for the design of bone fixation plates. Standard pre-contoured plates are designed based on the mean shape of a certain population. We propose a computational process to design implants while reducing the amount of required intra-operative shaping, thus reducing the mechanical stresses applied to the plate.

Intercalary femur allografts are an acceptable alternative after tumor resection.

Background: With the improved survival for patients with malignant bone tumors, there is a trend to reconstruct defects using biologic techniques. While the use of an intercalary allograft is an option, the procedures are technically demanding and it is unclear whether the complication rates and survival are similar to other approaches.

Questions/purposes: We evaluated survivorship, complications, and functional scores of patients after receiving intercalary femur segmental allografts.

Allograft selection for transepiphyseal tumor resection around the knee using three-dimensional surface registration.

Transepiphyseal tumor resection is a common surgical procedure in patients with malignant bone tumors. The aim of this study is to develop and validate a computer-assisted method for selecting the most appropriate allograft from a cadaver bone bank. Fifty tibiae and femora were 3D reconstructed from computed tomography (CT) images.

Angle estimation of human femora in a three-dimensional virtual environment.

The estimation of human femur morphology and angulation provide useful information for assisted surgery, follow-up evaluation and prosthesis design, cerebral palsy management, congenital dislocation of the hip and fractures of the femur. Conventional methods that estimate femoral neck anteversion employ planar projections because accurate 3D estimations require complex reconstruction routines. In a recent work, we proposed a cylinder fitting method to estimate bifurcation angles in coronary arteries and we thought to test it in the estimation of femoral neck anteversion, valgus and shaft-neck angles.