Results of a Pilot Study on the Safety and Early Efficacy of Novel Polymethyl Methacrylate Microspheres and a Hyaluronic Acid Device for the Treatment of Low Back Pain Caused by Degenerative and Diseased Intervertebral Discs of the Lumbar Spine

Abstract

Background Low back pain (LBP) costs the healthcare system billions of dollars each year. Intervertebral disc (IVD) degeneration is a significant cause of LBP, due to structural defects, biomechanical instability, and inflammation. First-line therapy for patients with LBP includes physical therapy, medication, and steroid injections. DiscSeal^TM was developed to provide patients who are refractory to first-line therapy with a minimally invasive treatment alternative to invasive surgical procedures. The product is a combination of poly-methyl methacrylate (PMMA) microspheres in hyaluronic acid (HA) that is injected under modified discography into the IVD. Methods Two pain specialist centers in Australia recruited eligible participants who were followed up for 180 days post-procedure. The procedure was conducted using a modified discography technique. Low back and leg pain was reported using the Visual Analogue Scale (VAS) while other endpoints included were Oswestry Disability Index (ODI), Clinician and Patient Global Impact of Change, and Patient Rating of Overall Health Status. The general analytical approach for all endpoints was descriptive in nature and 95% confidence intervals of means were estimated. Results The pilot study achieved its primary objective which was an absence of peri-treatment or post-treatment device-related Serious Adverse Events (SAE) during the first 90 days. There were no device-related serious adverse events recorded throughout the study. The mean LBP percentage change from baseline at 90 and 180 days was -27.0% and -42.3% respectively. The mean ODI percentage change from baseline at 90 and 180 days was -22.3 and -14.2% respectively. End of study improvements shows a 67.8% (20.83) increase in Overall Health Status, as well as positive results for Participant and Clinician Global Impact of Change. These results were achieved based on treating one diseased IVD, although 83.3% of patients were diagnosed with multiple diseased IVDs. Conclusions The results from this pilot study showed that DiscSeal^TM is safe and well-tolerated. Early efficacy shows that DiscSeal^TM may be a promising treatment option for people suffering from discogenic LBP that have not responded to first-line treatment options. A larger, statistically powered study where all diseased discs are treated should be completed to validate the promising results from this early feasibility study.

Keywords: chronic low back pain (clbp); clinical trial; degenerative disc disease; discogenic back pain; first in human.

Figure 1. Visual Analogue Score for Low back pain and Leg pain and Oswestry Disability Index Score for the Intent to Treat Population (all Participants)

LBP - Low back pain, VAS - Visual Analogue Scale, ODI - Oswestry Disability Index

Figure 2. Visual Analogue Scores for Low Back Pain Over Time for all Patients, the Per Protocol Population and Single Disc Diseased Participant