Yuji Okuno (Okuno Clinic, Tokyo, Japan) gave an update on the status of musculoskeletal embolization for pain management and sports related injuries at the GEST Symposium this year (Global Embolization Cancer Symposium Technologies; 9–12 May, New York, USA).
He began by detailing the first report on musculoskeletal embolization, published in the Journal of Vascular and Interventional Radiology (JVIR) in 2013 by himself and colleagues, which demonstrated the feasibility and efficacy of transcatheter arterial embolization (TAE) using imipenem and cilastatin sodium for tendinopathy and enthesopathy refractory to nonsurgical management. Imipenem and cilastatin sodium have been used as a temporary embolic agent in Japan since 1990, and the Japanese investigators selected the material for its established safety record. Local tenderness score, used as a proxy for pain, reduced rapidly following the procedure, and pain disappeared at three months.
Okuno and his colleagues were encouraged by the results of this pilot study, seeing potential in the procedure’s use to alleviate pain. Current understanding is that chronic inflammation leads to an increase in abnormal neovessels, and that embolizing these vessels and reduce pain and consequently the dependence on alternative pain management strategies, such as taking opioids. However, more data are needed to solidify TAE’s position as a pain management treatment, and Okuno said at GEST that comparative studies of TAE versus a placebo and TAE versus another treatment are needed.
Recently, there has been an upswell in interest around musculoskeletal embolization, with multiple studies investigating the technique’s use in the knee, shoulder and elbow. Sandeep Bagla (chair of Interventional Radiology at the Vascular Institute at Virginia, Woodbridge, USA) presented the positive results on an early preclinical study of GAE in 20 patients with mild to moderate knee osteoarthritis in spring this year at the Society of Interventional Radiology’s annual meeting (SIR; 23–28 March, Austin, USA). A randomised controlled trial focusing on GAE in a larger cohort is underway. Meanwhile, Mark Little (Royal Berkshire Hospital, Reading, UK) is the principle investigator for the first clinical trial examining GAE in knee osteoarthritis patients in Europe, the GENESIS trial. A placebo-controlled randomised controlled superiority trial embolization in the knee headed by Steve Landers (Barwon Medical Imaging, Barwon Health, Geelong, Australia) has also recently completed enrolment in Australia.
Musculoskeletal embolization for pain management in athletes
Specifically thinking about sports injuries, Okuno believes musculoskeletal embolization will have a much larger role to play in the future of pain management for athletes. He gives two case examples at GEST.
The first case report is of a 26-year-old male patient with patellar tendinopathy. The patient is a professional goal keeper for a football team in the Japanese top league, and does not wish to undergo surgery due to the slow post-operative recovery. The patient’s chief complaint is knee pain, which is exacerbated by running, jumping, flexing and kneeling, Okuno informed the audience, “all movement crucial to his profession”. The goalkeeper was resistant to conservative treatment, having had one corticosteroid injection and two hyaluronic acid injections prior to trying TAE.
Post-procedural imaging revealed that the abnormal vasculature was no longer visible, and the patient’s pain score as measured by the Numerical Rating Scale (NRS) dropped from eight to two within a month, and was zero three months post TAE. Two days after the procedure, the patient returned to light training, and was back to full training with the rest of the football team two weeks after the embolization was performed. Six weeks’ post-procedure, the patient had their first competitive game. “The patient had rapid progression and quick reduction in symptoms after the embolization”, Okuno described. He opined, “This is particularly advantageous for sportspeople, as they cannot rest for long. At two-years follow-up, this patient’s knee has a normal appearance”.
The second case Okuno presented to the GEST audience was a chronic hamstring injury in a long distance athlete, who competed at the Rio Olympics. The 34-year-old female athlete complained of hip pain, and was resistant to conservative treatment after one year. “It is very difficult to have surgery and then go back to training”, Okuno explained, “so she was reluctant to have that treatment, even though this was recommended surgery by the orthopaedic surgeon”. Instead, Okuno performed embolization twice in two months. She was back training again after three to four months.
Okuno used these success stories to promote the potential of embolization to allow athletes and active patients to continue engaging in their chosen sport pain free. Marc Sapoval, who was chairing the session “Vanguard in embolization” at GEST, said in response to Okuno’s presentation: “I am very optimistic about this being a new area of embolization for the future”.