Background: -Lower back pain is an incredibly common condition, affecting approximately 80% of adults at some point in their lives. Low back pain is the leading cause of years lived with disability in both developed and developing countries, and sixth in terms of overall disease burden. Over 619 million people around the world are affected by back pain and it costs the US economy over 600 billion dollars a year. Despite decades of research and promising therapies, a durable non-surgical treatment has yet to show any potential benefit. While conservative therapy such as non-steroidal anti-inflammatory medication, facet injections, and physical therapy may help for a subset of people with limited or acute back pain, the vast majority of people suffering with chronic low back pain largely fail to benefit from these options. 

Purpose: Lumbar artery embolization (LAE) using imipenem/cilastatin (IMP/CS) has been described in one study as a possible treatment of lower back pain. The purpose of this study was to determine whether utilizing a novel resorbable embolic particle (SakuraBead) for LAE was technically feasible, compare the performance to other embolic agents (IMP/CS and permanent microspheres), and evaluate safety in a porcine model. 

Materials and Methods: A swine model (5 large white swine, 30-35kg) was utilized given similar lumbar artery anatomy to humans. A 4 Fr reverse curve catheter was used to select the origin of the lumbar arteries, followed by superselection with a 1.7 Fr microcatheter. Embolization was performed after administration of nitroglycerin either distal or proximal to a visible communication with the anterior spinal artery seen on cone beam CT. Embolic agents utilized included two formulations of SakuraBead, Embozene 100 µm, and IMP/CS (500 mg/500 mg). The embolization endpoint was pruning of the distal vasculature. The swine were evaluated for complications by the study veterinarian. They were sacrificed at varying time points (1-6 days post-procedure) and the spine with paraspinal tissues were sent for histopathological analysis.

Results: In swine 1-2, LAE was performed bilaterally at 3 lumbar artery levels distal to the visualized anterior spinal artery communication. Two formulations of SakuraBead were used in each swine, with either Embozene 100um or IMP/CS used for the 3rd level. In swine 3-5, in order to evaluate for safety of LAE in the case of an unrecognized communication to the spinal artery, LAE was performed proximal to the visualized communication to the anterior spinal artery with 2 different formulations of Sakurabead and IMP/CS at 3 levels in each pig. The operators did not discern a difference in ease of administration between the various embolic agents. No animals experienced adverse events following the procedure. Histopathological analysis demonstrated no visible embolic particles, which could be related to tissue processing or the small volume of embolic.

Conclusion: SakuraBead demonstrated similar performance to Embozene and IMP/CS for LAE in a swine model. There was no evidence of paralysis even when embolization proximal to a known communication to the spinal artery was performed in 3 swine. This indicates that Sakurabead could be considered as a potentially safe resorbable embolic agent in LAE for low back pain.