Genicular artery


ligaments, overall pain improvement after GAE may be less impressive.


embolization The future standard of care for inflammatory conditions By Sandeep Bagla, MD


I


n the past 5 years, the notion of embolizing hyperemic, inflamed tissue to treat musculoskeletal pain has been tested in several early human


studies. The primary goal of genicular artery embolization (GAE) is to disrupt the inflammatory process and cause ischemic neurolysis of synovial sensory nerves, leading to decreased pain and disability. This pioneering work has been led by Yuji Okuno, MD, PhD.


The knee has been the anatomic site of greatest interest due to the large number of people affected with osteoarthritis- related knee pain. Since the publication of early data from Japan demonstrating feasibility and efficacy of GAE, my team completed a prospective single-arm study and, subsequently, a randomized controlled trial (RCT) of GAE vs. a sham procedure (currently undergoing peer review). The latter confirmed that GAE results in an effect greater than placebo in reducing pain and disability, which is a critical step in proving the value of pain- reducing procedures.


Our studies were both focused on patients with mild- to moderate-grade


HISTORY OF IR TIMELINE


Interventional radiology is a specialty that redefines innovation. This timeline showcases the major events in IR history, from the first angioplasty to the recognition of IR as an independent specialty.


osteoarthritis (OA) because we believe that pain in late-stage OA is more a result of fibrosis than inflammation and would not respond as well to embolization. An investigation led by Lee et al. in 2019 supported this hypothesis, demonstrating that severe OA patients did not respond as well as those with moderate or mild grade stages.


Predictors of clinical success Over the years, we have noticed other predictors of clinical success, including the ability to localize knee pain via physical exams and then targeting that focus during embolization. The identification of reproducible focal pain in the area of synovitis leads to a higher rate of success, a phenomenon also described by Dr. Okuno. Additionally, there seems to be a correlation between the ability to reproduce the patient’s knee pain during selective angiography and subsequent improvement of symptoms. We have also observed that, when patients have concurrent conditions in addition to OA, such as severe chronic degeneration of the menisci or


1964 1965


Charles Dotter publishes “Transluminal treatment of arteriosclerotic obstruction. Description of a new technic and a preliminary report of its application”; angioplasty begins to take root.


In contrast to embolization for spontaneous hemarthrosis after arthroplasty, there are angiographic differences in the setting of OA. The size and vascularity of the synovium is often less pronounced leading to a subtler appearance of “tumor blush” in the regions of synovitis. More delayed subtraction angiography, the use of vasodilators and intraprocedural heparin may all improve the detection of hyperemic tissue while reducing the possibility of spasm or thrombosis. The superior-lateral compartment, commonly affected in post-arthroplasty hemarthrosis due to repeated impingement by the prosthesis, is less often the location of synovitis in the OA patient. From a technical perspective, the selection of the superior medial and lateral genicular arteries can be technically challenging. They can arise from a common trunk or independently but usually in a severe acute angle from the popliteal artery. Although challenging to catheterize, these arteries are both significant contributors to synovial mediated pain on both the medial and lateral aspects of the knee joint.


After GAE, patients usually report improvement in knee pain within a few weeks, if not within the first week. A transient increase in knee stiffness may last 24–48 hours. While complications are rare and mild for the most part, we have seen two cases of transient sensory deficits in the plantar aspect of the foot. However, we have not seen this complication with spherical embolic particles 100 microns or larger.


1966


Embolization therapy to treat tumors and spinal cord vascular malformations by blocking the blood is created.


4 IRQ | SPRING 2021 SUPPLEMENT


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