Comparison of IntraArticular Platelet-Rich-Plasma to Corticosteroid Injections for Patients with Zygapophyseal Joint (Z-Joint) Low Back Pain Confirmed by Dual Intra-Articular Local Anesthetic Injections: A Triple Blinded Randomized Controlled Trial.

Abstract/Project Summary Background: Zygapophyseal joint (Z-joint) pain represents up to 40% of lower back pain (LBP), a very common and disabling health issue. There are currently two treatment options for patients with Z-joint LBP unresponsive to conservative treatment: corticosteroid (CS) injections and radiofrequency ablation. CS injection is a shorter, less invasive and readily available procedure. Despite its accepted use, it has not shown its efficacy over placebo.

The use of platelet-rich plasma (PRP) has been investigated for LBP treatment. PRP injection has the same advantages as CS and recent studies suggest that PRP injections are more effective than cortisone from two to six months post treatment. However, no blinded controlled trials have compared these two treatments, and no data is available on the efficacy of PRP after six months for LBP treatment.

Purpose: The purpose of this study is to compare the effect of intra-articular leucocyte poor (LP) PRP to CS injections on pain, function and quality-of-life at 1, 3, 6, 9 and 12month post treatment. The two main outcomes will be the ODI score improvement and the proportion of participants who needs a second injection in each group at one year post treatment.

Study Design: Triple-blinded randomized controlled trial Patient Sample: Fifty participants with radiological signs of osteoarthritis and Z-Joint LBP confirmed by dual intra-articular local anesthetic injections will be recruited and randomized in two groups: CS and LP-PRP injection groups.

Method: Participants will be assessed in person, by mail or by phone at baseline and at 1, 3, 6, 9 and 12-months post-treatment by a blinded evaluator. Pain will be assessed by a visual analogue scale (VAS) when bending over, function by the Oswestry Low Back Disability Index (ODI), quality of life by the SF36 questionnaire and satisfaction by the Modified McNabb Scale.

Inclusion Criteria:

• - 40 years old or more; given the low prevalence of facet pain in younger adults
• LBP present for more than six months, with an axial predominance
• Persistent LBP after three months of non-interventional treatment
• Pretreatment ODI score of at least 30/100 (moderate disability associated with LBP)
• Pretreatment LBP VAS of at least 4/10
• 80% LBP reduction 30 minutes after 2 intra-articular diagnostic blocs with Xylocaine and Marcaine
• Radiological signs of facet joint degeneration (on X-rays, CT Scan or MRI)
• Absence of neurological deficit
• Sufficient knowledge of French or English to complete the questionnaires

Exclusion Criteria:

• - Less than 40 years old
• Failure to achieve intra-articular diagnostic block
• Intra-articular injection of CS 3 months or less before recruitment
• Oral corticosteroid use in the last two weeks
• Inflammatory disease
• Systemic infection
• Infection at injection site
• Vertebral fracture
• Spine tumour
• Surgical intervention at injection site prior to the study or planned
• Cognitive disorder that impairs the ability to answer the questionnaires
• Pregnancy
• Breastfeeding
• Coagulopathy affecting platelets
• Drug affecting platelets that cannot be stopped (except acetylsalicylic acid)
• Intolerance or allergies to local anesthetics, contrast agent, CS, and blood products