Gluing the Annulus
Repairing the annulus after a micro discectomy is not a new idea. But using glue (specifically fibrin glue) just might be. James Iatridis, Ph.D. and his team have been focusing their efforts on furthering the status of annulus fibrosus repair. They are particularly hoping to find solutions for those who have herniations and who undergo micro discectomy. Dr. Iatridis, director of spine research at the Mt. Sinai School of Medicine, tells OTW, “The goal should be not just to take away the herniated tissue, but to repair the annulus. We have just published two review articles describing the status of annulus fibrosus repair. In the first paper we describe what needs to be repaired biomechanically and strategies for repairing the injured intervertebral disc with different biomaterials. Our concept is that we must restore both annulus fibrosus integrity (detectable with torsional measurements) and nucleus pulposus pressurization (detectable with intradiscal pressure or axial biomechanics measurements).”
“In these articles we describe what an injury to the annulus fibrosus does to the biomechanics and the biological environment, as well as ways to characterize that injury. For example, a puncture in the annulus fibrosus results in a loss of pressurization of the disc. Contrast this with a herniation where there is a greater disruption in the annulus fibrosus. We’re screening different treatments in the lab for degenerative disc disease. Our organizing principle for annulus repair is to achieve three design criteria: the material must mechanically match the native material properties of the annulus fibrosus, support the growth of intervertebral disc cells, and be strongly adherent to seal annulus fibrosus defects under physiological strain levels.”
“At the recent Orthopaedic Research Society (ORS) meeting in San Antonio, we presented two abstracts characterizing our fibrin-based biomaterial which shows promise as an annulus fibrosus sealant. In the first, we enhanced our formulation of a Fibrin-Genipin adhesive with the addition of cell adhesion molecules for improved cell growth. This gel is exciting because it meets our design criteria and it doesn’t degrade as quickly as unmodified fibrin gels. The second abstract described our characterization of this Fibrin-Genipin adhesive in a novel organ culture model, demonstrating biomechanical restoration, strong adhesion with the native tissue, and transport of annulus fibrosus cells from the native tissue into the gel. Given our promising results, we will pursue animal model testing and hope these studies of annular repair will translate to therapies for lumbar microdiscectomy patients that minimize both the likelihood of reherniation as well as further disc degeneration.”
More ICU Better for High-Risk THA?
Yes! Says the winner of the 2012 OREF (Orthopaedic Research and Education Foundation)/CCJR (Current Concepts in Joint Replacement) Clinical Practice Award. Atul Kamath, M.D., who is completing a fellowship at Mayo Clinic in Rochester, Minnesota, tells OTW about his study on unplanned ICU following THA (total hip arthroplasty). “Elective hip and knee arthroplasty is a safe procedure, but the risks of morbidity and mortality are real, with certain risk factors more highly associated with post-operative complications. We wanted to identify those patients who are more at risk and to find out how to shepherd them through the system along safe pathways. This was a two-part study: in the retrospective portion, we looked at a large number of patients and developed a model for risk that included age, revision surgery, body mass index, prior myocardial infarction, and creatinine function. We found that with each risk factor, there is an inherent risk of unplanned ICU admission post-operatively; and, as you combine risk factors, the risk increases dramatically.”
“In the prospective part of our work, we took those patients who were at the highest risk and sent them to the ICU immediately after surgery to see if it made a difference. In fact, this did decrease mortality and unplanned admissions. But, of course, there remains a resource allocation issue—we cannot send all high-risk patients to the ICU at a tertiary referral center. So now we aim to fine-tune the model to ensure that we are sending only the most high risk patients as identified by our modeling. There is also the opportunity to gather data post-discharge, such as readmission rates and other factors important in our current healthcare climate. Over the next six months, we will focus on developing metrics for cost. We would also like to track our initial prospective THA cohort for 6-12 months and get a sense of how they doing, as well as comparing these patients to those who did not go through our triage system.”
Orthopedic Literature: Cut Through the *&^%$
Tired of wading through piles of journals? Simplicity has arrived…and it is called OrthoEvidence. Mohit Bhandari, M.D., Professor and Research chair in Orthopaedic Surgery at McMaster University in Canada is making orthopedists lives substantially easier. Dr. Bhandari tells OTW, “At the end of the day, if there is no way for us to get reliable high quality information to surgeons in a timely way, research in journals has little impact. OrthoEvidence (OE) is designed to bridge the gap between quality evidence and current medical practice, a real issue when there is so much literature being released each month. Our process is rigorous, and involves scanning 40 journals monthly. We look for the best evidence, sum it up, do a critical appraisal, and create what we call an Advanced Clinical Evidence (ACE) report. We are focusing on high quality evidence from randomized clinical trials and meta-analyses; and while high impact journals like Journal of Bone and Joint Surgery (JBJS) remain trusted resources for orthopedic surgeons, they publish only a fraction of the best evidence in our field around the world. This means that the average orthopedic surgeon is missing out on practice changing information.”
“Thus far we have partnered with 25 leading orthopedic association and societies from around the world. OE is being accessed in over 170 countries by over 30, 000 orthopedic surgeons. With over 1, 250 ACE reports in our database we are happy to be making the daily lives of orthopedic surgeons run more smoothly.”
Biomarkers for Osteoarthritis: Where Are We?
Using the model employed by the Foundation for the National Institutes of Health (FNIH) in the development of biomarkers to monitor harmful effects of drugs on the kidney, osteoarthritis researchers are making critical steps to advance methods to facilitate the development of effective osteoarthritis treatments. Virginia Kraus, M.D., Ph.D., professor of Medicine in the Division of Rheumatology at Duke University Medical Center, is co-leading the effort with Dr. David Hunter, professor of Medicine at the University of Sydney in Australia, to validate biochemical and imaging markers for osteoarthritis (OA). She tells OTW, “We continue to work with industry and the FNIH to find biomarkers that predict disease progression. The study is going well and we will present our first abstract in April 2013 at the Osteoarthritis Research Society International. That work shows the predictive capability of imaging biomarkers from MRIs related to changes in the morphometry of the knee. We are seeking additional funding partners for this work as well as additional cohorts to validate the results. Studies demonstrating a structural modification of OA, such as a recent trial from Europe, may help with the further qualification of markers. Everyone we speak with agrees that this work is vital to making advances in osteoarthritis treatment.”
Andrew I. Spitzer, M.D.: New Member of Israel Orthopaedic Association
Dr. Spitzer, director of the Joint Replacement Program at the Cedars-Sinai Orthopaedic Center in Los Angeles, is being recognized for his work in Israel. He has traveled to that country more than a dozen times to share his knowledge with local surgeons, often treating patients for free. In a gesture of appreciation, the Israel Orthopaedic Association has made Dr. Spitzer an honorary member.
