Robots and tools for remodeling bone

The field of robotic surgery has progressed from small teams of researchers repurposing industrial robots, to a competitive and highly innovative subsection of the medical device industry. Surgical robots allow surgeons to perform tasks with greater ease, accuracy, or safety, and fall under one of four levels of autonomy; active, semi-active, passive, and remote manipulator. The increased accuracy afforded by surgical robots has allowed for cementless hip arthroplasty, improved postoperative alignment following knee arthroplasty, and reduced duration of intraoperative fluoroscopy among other benefits. Cutting of bone has historically used tools such as hand saws and drills, with other elaborate cutting tools now used routinely to remodel bone. Improvements in cutting accuracy and additional options for safety and monitoring during surgery give robotic surgeries some advantages over conventional techniques. This article aims to provide an overview of current robots and tools with a common target tissue of bone, proposes a new process for defining the level of autonomy for a surgical robot, and examines future directions in robotic surgery

Prevalence of haptic feedback in robot-mediated surgery : a systematic review of literature

© 2017 Springer-Verlag. This is a post-peer-review, pre-copyedit version of an article published in Journal of Robotic Surgery. The final authenticated version is available online at: https://doi.org/10.1007/s11701-017-0763-4With the successful uptake and inclusion of robotic systems in minimally invasive surgery and with the increasing application of robotic surgery (RS) in numerous surgical specialities worldwide, there is now a need to develop and enhance the technology further. One such improvement is the implementation and amalgamation of haptic feedback technology into RS which will permit the operating surgeon on the console to receive haptic information on the type of tissue being operated on. The main advantage of using this is to allow the operating surgeon to feel and control the amount of force applied to different tissues during surgery thus minimising the risk of tissue damage due to both the direct and indirect effects of excessive tissue force or tension being applied during RS. We performed a two-rater systematic review to identify the latest developments and potential avenues of improving technology in the application and implementation of haptic feedback technology to the operating surgeon on the console during RS. This review provides a summary of technological enhancements in RS, considering different stages of work, from proof of concept to cadaver tissue testing, surgery in animals, and finally real implementation in surgical practice. We identify that at the time of this review, while there is a unanimous agreement regarding need for haptic and tactile feedback, there are no solutions or products available that address this need. There is a scope and need for new developments in haptic augmentation for robot-mediated surgery with the aim of improving patient care and robotic surgical technology further.Peer reviewe

Acoustic Emission Measurement System in Diagnostic of Cartilage Injuries of the Knee

Abstract The measurement system BONEDIAS (Bone Diagnostic System) was developed as a non-invasive diagnostic method, based on the analysis on the acoustic emission from the knee joint. Knee squats of a patient will release acoustic emission in high temporal resolution and well correlated to the angle of knee flexion. The physician will get the relevant information concerning arthritic lesions in the knee joint (well characterized acoustic emission, singular events without a follow up of further emission), acoustic emission due to elevated intra-articular friction caused by e.g. cartilage lesions, inappropriate surface roughness, a lack of synovial fluid or crack initiation in the femur. Over 100 patients were analyzed with the measurement system BONEDIAS, afterwards the results were compared with the intra-operative views (arthroscopy and arthroplasty of the knee). Other parameters were studied, concerning the relation between the age and the sex of the subjects, the length of the femur, thigh thickness, the body mass index, the anatomical axis of the knee and the appearance and severity of the cartilage lesions. The study was made with the purpose to see if there was a correspondence between the cartilage disorders, the intraoperative views (arthroscopy and the arthroplasty of the knee) and the acoustic emission measurements, performed one day before the surgery. Because there arent at this moment cheap and standards methods who can determine the early cartilage injuries, this study is supposed (concording with the results) to open new ideas and new advantages in the diagnostic of this often disease, using the acoustic emission measurement system. The results obtained, 50% correspondence for the gr. 0, I and II Outerbridge lesions are more important, more significant that the other results, with over 60% correspondence for the advanced osteoarthrosis. The obtained acoustic emission signals, corresponding to the intra-arthroscopic findings showed the importance of this method to identify the early cartilage injuries. The method is not perfect and the results (50%) are not really statistically significant, so that we can introduce this method on a large scale, but offers important information that should be used in the future. Also, there isn’t a perfect method to compare the acoustic emission signals with the intra-arthroscopic findings. Every patient was analysed separately and with his corresponding measurement compared, that means a lot of time (20 – 30 minutes for the measurement and the other questions and clinical tests and another 15 minutes to analyse the signals and compare them with the intra-operative findings). For a study this can be accepted, but for clinical every day use maybe not. A standard interpretation and analyse method, maybe after clinical large trials, if such a method can be developed, could bring big advantages for the early determination of the cartilage injuries. In conclusion, the study had offered important informations about the importance of accoustic emission measurements, that can be used for the future studies and with some improvements, this method , cheap and non-invasive, but at this moment a little beat time-consuming, can be helpful in the diagnose of the early cartilage injuries

Clinical and Imaging Assessment of Metal on Metal Hip Patients

A high failure rate of metal-on-metal (MoM) hip implants prompted regulatory authorities to issue worldwide product recalls. The cause for their failure and decisions surrounding the need for revision is complex due to poor understanding of the toxic effects of metal debris. In addition to local soft tissue destruction, circulating cobalt can cause rare but fatal cardiotoxicity. This thesis describes the detection of metal cobalt-chromium within the liver of a patient with highly elevated blood cobalt (587ppb) using novel MRI imaging techniques, validated by liver biopsy and micro x-ray fluorescence. The prevalence of tissue metal deposition and potential cardiotoxic effects were assessed through a prospective case controlled cohort study. Ninety patients were recruited into three age and gender-matched groups according to blood metal levels. All underwent detailed cardiovascular and liver phenotyping using MRI (for myocardial volumes and function, T2*, T1 and Extra-Cellular Volume mapping), echocardiography, and blood biomarker sampling. T2* is a novel MRI biomarker of tissue metal deposition. Blood cobalt levels among the cohort ranged 0.1 to 118ppb, which is still seen in patients presenting for clinical follow-up. No significant between-group differences were found for cardiac volume or function, nor was there any difference in tissue characterization using T1, T2* and ECV. Higher blood cobalt levels did not translate to increased metal deposition within the heart or liver.The application of these results were analsyed through a multi-disciplianary team setting designed to aid complex decisions of who, when and how to treat MoM patients surgically. By analysis of MDT recommendations compared to the treatment undertaken it was demonstrated that an MDT approach is an acceptable evidence-based aid to decision-making.This thesis concludes that cobalt tissue deposition can be detected using non-invasive MRI techniques, however metal deposition is not commonly seen with blood cobalt levels upto 118ppb with reassuringly little cardiotoxic effects. These results help reassure clinicians managing MoM patients through an MDT approach

Quantitative MRI and 3D-Printing for Monitoring Periprosthetic Joint Infection

Joint replacements are becoming increasingly commonplace with over 130,000 joint arthroplasties being performed annually in Canada. Although joint replacement surgery is highly successful, implants do occasionally fail and need to be replaced via costly and difficult revision surgery. Periprosthetic joint infection (PJI) has recently become the leading reason for revision of both hip and knee replacements, which is unfortunate because PJI is difficult to diagnose and treat effectively; diagnosis is made particularly difficult by the lack of established non-invasive (imaging) means of evaluating PJI. This thesis aims to demonstrate that magnetic resonance imaging (MRI) has potential for diagnosing and monitoring PJI through advances in implant design and novel application of quantitative imaging. The recent proliferation of metal 3D-printing has already inspired the clinical use of 3D-printed porous metal devices due to their favorable osseointegration and mechanical properties. This thesis explores an important MRI benefit to porous implants: their decreased effective magnetic susceptibility and proportional decrease in imaging artifacts. This is relevant to PJI because MRI is already well-established in diagnosing musculoskeletal infections, but metals cause image obscuring signal loss. This work shows that 3D-printed porous metal structures are likely to avoid this limitation, as their effective magnetic susceptibility is linearly proportional to porosity; if true, MRI will be able to diagnose PJI as easily as non-prosthetic joint infections. This thesis describes a novel use for two important parameters measured by quantitative MRI: effective relaxation rate (R2*) and magnetic susceptibility (QSM; quantitative susceptibility mapping). This work seeks to address an important unmet need in PJI treatment – the ability to monitor drug release during localized antibiotic delivery – by exploiting these parameters’ proportionality to gadolinium concentration. This idea is centered around using gadolinium-based MRI contrast agents as a surrogate small-molecule that acts as a proxy for drugs to study diffusion-controlled release. An initial implementation of this concept showed promising results, including the ability to fit the data to a mathematical model of drug release. This shows the potential of MRI as a non-invasive means of monitoring localized antibiotic treatment of PJI post-revision

MR imaging of osteochondral grafts and autologous chondrocyte implantation

Surgical articular cartilage repair therapies for cartilage defects such as osteochondral autograft transfer, autologous chondrocyte implantation (ACI) or matrix associated autologous chondrocyte transplantation (MACT) are becoming more common. MRI has become the method of choice for non-invasive follow-up of patients after cartilage repair surgery. It should be performed with cartilage sensitive sequences, including fat-suppressed proton density-weighted T2 fast spin-echo (PD/T2-FSE) and three-dimensional gradient-echo (3D GRE) sequences, which provide good signal-to-noise and contrast-to-noise ratios. A thorough magnetic resonance (MR)-based assessment of cartilage repair tissue includes evaluations of defect filling, the surface and structure of repair tissue, the signal intensity of repair tissue and the subchondral bone status. Furthermore, in osteochondral autografts surface congruity, osseous incorporation and the donor site should be assessed. High spatial resolution is mandatory and can be achieved either by using a surface coil with a 1.5-T scanner or with a knee coil at 3 T; it is particularly important for assessing graft morphology and integration. Moreover, MR imaging facilitates assessment of complications including periosteal hypertrophy, delamination, adhesions, surface incongruence and reactive changes such as effusions and synovitis. Ongoing developments include isotropic 3D sequences, for improved morphological analysis, and in vivo biochemical imaging such as dGEMRIC, T2 mapping and diffusion-weighted imaging, which make functional analysis of cartilage possible

Imaging findings after meniscal repair with degradable polyurethane scaffold: preliminary results.

Purpose / Introduction: To date, there are no satisfactory solutions to the meniscal originated knee pain post meniscal tear repair. In this study a newly developed polyurethane material that has the intended properties of reducing pain and inducing tissue growth in a damaged meniscus is tested. Materials and Methods: All patients will be imaged using conventional and dynamic MR imaging techniques at 1 week and 3, 12 and 24 months after surgery. The influx of gadolinium contrast in a tissue during the first three minutes after injection gives a measure of the vascularisation, capillary permeability, perfusion and composition of the interstitial fluid. It can be measured using dynamic MRI and is represented as a Time Intensity Curve (TIC). This curve permits an evaluation of the healing process after surgery. Discussion / Conclusion: Thus far 11 patients have received meniscal implants. Eight medial and three lateral menisci were operated. All implants covered the posterior horn with 3 reaching halfway into the meniscal body and one extending into the anterior horn. The average length of the scaffold meniscus measured on MR imaging was 45mm. In the first week after surgery, the capsule and suture area display fast and intense enhancement typical for post-operative inflammation and the formation of early scar-tissue. There is no enhancement in the base or the tip of the scaffold meniscus. After three months the speed and intensity of enhancement in the capsule and suture area between the remnants of the native meniscus and the scaffold have decreased indicating maturation of scar-tissue. However, the base of the scaffold meniscus now shows enhancement. This can only be explained by proliferation of blood vessels from the capsule and theresidual meniscus wall into the scaffold meniscus. The tip of the matrix shows limited enhancement in some patients after three months. On anatomical MR images, the signal intensity (SI) of the implanted scaffold is close to that of water on both T1- and T2-weighted spin echo and turbo spin echo sequences in the first week. After three months the SI decreases but is still clearly higher than that of the native meniscus. The implants in the posterior horn all had a normal position and no loosening of the sutures or tears of the scaffold were found. After three months, one of the patients had slight expulsion of body of the scaffold meniscus but this is a common finding in transplanted menisci

Developing Implantable Hydrogel-Based Sensors to Measure Biomarkers in Synovial Joint Fluid Using Plain Radiography

The goal of my dissertation research is to develop implantable sensors that attach to prosthesis prior to implantation and measures biomarkers of infection in joint fluid in order to detect, monitor, and study infection using plain radiography. Joint replacement surgeries are common procedures improving the mobility and lives of millions of people worldwide. Although the surgeries are generally successful, about 1% of prosthetic hips become infected. If the infections are not detected and treated promptly with antibiotics and surgical debridement, device removal is almost always required to treat the infections. Therefore, it’s important to detect post-surgery infections early and monitor the effect of therapies for effective treatment. The sensors developed in this report can be attached to prosthetic joints and enable analysis of synovial fluid biomarkers for local infection in vivo using plain radiography. The biomarkers of infection focused here are pH, carbon dioxide, and viscosity of synovial fluid. The pH and carbon dioxide sensors are based on a pH-responsive hydrogel, whereas the viscosity sensor is based on the velocity of a falling bead. Radiopaque markers are incorporated into the sensor to enable biochemical measurements, radiographically. The sensors can be expanded to other biomarkers of infections, as well as other disease conditions. The sensors developed provide noninvasive local chemical measurements using plain radiography which is simple, rapid, and already acquired as part of the standard of care for early detection of prosthetic joint infections

Leukocyte and bacteria imaging in prosthetic joint infection

There has been a significant increase in the number of joint prosthesis replacements worldwide. Although relatively uncommon, complications can occur with the most serious being an infection. Various radiological and nuclear imaging techniques are available to diagnose prosthetic joint infections (PJI). In this review article, we describe the pathophysiology of PJI, the principles of nuclear medicine imaging and the differences between Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). The value of nuclear medicine techniques for clinical practice is also discussed.Then we provide an overview of the most often used radionuclide imaging techniques that may be helpful in diagnosing prosthetic joint infection: the 67Ga-citrate, labelled white blood cells in vitro and in vivo (monoclonal antibodies directed against specific targets on the leukocytes), and 18F-fluorodeoxyglucose (18F-FDG). We describe their working methods, the pitfalls, and the interpretation criteria. Furthermore, we review recent advances in imaging bacteria, a molecular imaging method that holds promises for the detection of occult infections. We conclude proposing two diagnostic flow-charts, based on data in the literature, that could help the clinicians to choose the best nuclear imaging method when they have a patient with suspicion of or with proven PJI