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Biomedical subjects

B Jaramaz

Publications and source records attributed to B Jaramaz.

7 recordsLinked to original sources
PubMed2001

Accuracy in tunnel placement for ACL reconstruction. Comparison of traditional arthroscopic and computer-assisted navigation techniques.

The purpose of this randomized, prospective study was to compare accuracy in tunnel placement as performed with a traditional arthroscopic anterior cruciate ligament (ACL) reconstruction technique and with KneeNavTM ACL, a computer-assisted surgical navigation technique. Two surgeons experienced in ACL reconstruction, but inexperienced in computer-assisted surgical navigation technique, each randomly used traditional arthroscopic guides or KneeNavTM ACL to drill a tunnel in twenty identical foam knees. Placement of the resulting tibial and femoral tunnels was measured with a computer-assisted digitizing method and compared to traditional biplanar radiographs. Statistical analysis with Student's t-test was used to compare the distance from the ideal tunnel placement to the femoral and tibial tunnels. Accuracy of tunnel placement with KneeNavTM ACL was significantly better than that obtained with the traditional arthroscopic technique. Distances from the ideal tunnel placement to the femoral and tibial tunnels were 4.2 +/- 1.8 mm (mean +/- SD) and 4.9 +/- 2.3 mm, respectively, for the traditional arthroscopic technique, and 2.7 +/- 1.9 mm (femur) and 3.4 +/- 2.3 mm (tibia) for KneeNavTM ACL. These differences were statistically different. Tunnel placement for ACL reconstruction with KneeNavTM ACL, an image-based, computer-assisted surgical navigation device with a simple and intuitive interface, was more accurate than with the traditional arthroscopic technique.

Anterior Cruciate Ligament↗
PubMed1998

Computer assisted measurement of cup placement in total hip replacement.

The introduction of image guided systems in total hip replacement surgery provides the ability to plan precisely the alignment of the acetabular cup before surgery, and to perform the surgery according to the preoperative plan. Preoperative planners (interactive computer programs for surgical planning) based on three-dimensional medical images allow planning of optimal placement of implant components based on simulated implant performance. Exact measurement of the cup position during surgery allows precise placement of the cup and accurate measurement of the final position of the cup relative to the pelvis. This measurement is used to evaluate the radiographic techniques for postoperative measurement of cup alignment. Malposition of the acetabular component increases the occurrence of impingement, reduces the safe range of motion, and increases the risk of dislocation and wear. Dislocation of the implant after total hip replacement remains a significant clinical problem. Not fully understanding the interaction between pelvic orientation and final acetabular cup alignment may be one of the main contributing factors in the continued significant incidence of dislocations after total hip replacement. In this study an attempt was made to link the preoperative planning, intraoperative placement, and postoperative measurement of cup placement in total hip replacement using computer assisted techniques.

Acetabulum↗
PubMed1998

The Otto Aufranc Award. Image guided navigation system to measure intraoperatively acetabular implant alignment.

There has been little clinical research to examine the effects of patient positioning and pelvic motion on the alignment of the acetabular implant during total hip replacement surgery. Until now, no tools were capable of accurately measuring these variables during the actual procedure. As part of a broader program in medical robotics and computer assisted surgery, a clinical system has been developed that includes several enabling technologies. The hip navigation system (HipNav) continuously and precisely measures pelvic location and tracks relative implant alignment intraoperatively. HipNav technology is used to gauge current clinical practice and provide intraoperative feedback to surgeons with the goal of improving the precision and accuracy of acetabular alignment during total hip replacement. This system provides surgeons with a new class of image guided measurement tools and assist devices. These tools successfully were introduced into the clinical practice of surgery with results showing the following: (1) There exist unpredictable and large variations in the initial position of patients' pelves on the operating room table and significant pelvic movement during surgery and during intraoperative range of motion testing; (2) current mechanical acetabular alignment guides do not account for these variations, and result in variable and in the majority of cases unacceptable acetabular alignment; and (3) press fitting oversized acetabular components influences the final cup orientation.

Anthropometry↗
PubMed1998

Computer assisted orthopaedic surgery. Image guided and robotic assistive technologies.

Technologies are emerging that will influence the way in which orthopaedic surgery is planned, simulated, and performed. Recent advances in the fields of medical imaging, computer vision, and robotics have provided the enabling technologies to permit computer aided surgery to become an established area which can address clinical needs. Although these technologies have been applied in industry for more than 20 years, the field of computer assisted orthopaedic surgery is still in its infancy. Image guided and surgical navigation systems, robotic assistive devices, and surgical simulators have begun to emerge from the laboratory and hold the potential to improve current surgical practice and patients' outcomes. The goals of these new clinically focused technologies are to develop interactive, patient specific preoperative planners to optimize the performance of surgery and the postoperative biologic response, and develop more precise and less invasive interactive smart tools and sensors to assist in the accurate and precise performance of surgery. The medical community is beginning to see the benefit of these enabling technologies which can be realized only through the collaboration and combined expertise of engineers, roboticists, computer scientists, and surgeons.

Biomedical Engineering↗
PubMed1995

Biomechanics for preoperative planning and surgical simulations in orthopaedics.

Surgical simulations are particularly appropriate for the large volume and expense of joint replacement procedures in orthopaedics. A first generation surgical simulator has been developed to model the implantation procedure for cementless acetabular and femoral components in total hip replacement surgery. The simulator is based upon finite element analysis and predicts the early postoperative mechanical environment that results from a proposed surgery. Since the short- and long-term clinical success of cementless hip replacement components is very dependent upon the initial mechanics of the bone-implant system, such simulations can help orthopaedic surgeons to develop better preoperative plans.

Biomechanical Phenomena↗