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We have previously demonstrated in people with chronic neck pain arising from a whiplash trauma who have failed previous conservative treatment that injection of platelet-rich plasma (PRP) into the facet joints is safe, and provides significant relief of pain and disability. The positive benefits were demonstrated, at 3-months, and maintained at 6-, and 12-months. Thus, this looked promising as a solution for those injured in whiplash mechanisms to improve their quality of life. But, science has a way to get your attention. Whereas, these initial studies focused on people attending a specialist musculoskeletal chronic pain clinic (Vivo Cura Health), there was no comparison group, blinding or randomization. People were highly selected and most attended rehabilitation at the same clinic. That is, they received the best of the best care. PRP was delivered in a proprietary manner, and audit of platelet counts prepared in this manner demonstrated platelet concentrations from 3.5x to 4.5x. So, all was good. We then partnered with the wonderful team at Western University in Ontario and controlled some of the unknown variables through a double-blind, randomized controlled trial, with an active control group receiving steroid injections as the comparator.
What Did We Find?
Both PRP and corticosteroid injections induced similar improvements in neck pain (1 month post) and self-rated disability (3 and 6 months post). Thus, PRP did not out-perform steroid injections, contrary to our research hypothesis. I suppose it was good that those receiving either injection noted a reduction of disability at 6-months, but as I’ve previously blogged, steroid injections are catabolic and carry risk factors, so not a route we would recommend for those with chronic neck pain post-whiplash injury.
Why the Difference in Findings?
Multiple factors may explain the discrepancy. Firstly, the sample investigated in the trial predominantly included those with longstanding idiopathic (possibly postural related) neck pain as compared to whiplash trauma. Secondly, this sample did not receive rehabilitation, although they may have pursued this – although we did not collect that data. And then there were differences in the preparation of PRP. The trial used a kit, as distinct from the proprietary method used at Vivo Cura Health. The trial used a leukocyte poor concentration (thinking that it would be less painful and would address degenerative joint pain), as compared to leukocyte rich preparation (generally recommended for soft tissue sprains/strains) used in the whiplash group. Finally, and possibly the biggest issue related to the platelet concentration people received. The system used has previously reported (unknown to the study authors at study inception) a platelet concentration of 1.3x, which is below the threshold for the definition of ‘PRP’, which is generally thought to require a concentration of 2x. Woops!!! It is hard to know which factors are most important, although it would be a good start to at least inject the ‘right dose’ of medication to gain an effect.
What Now?
What I love about research is collaborating with very smart people that are just as passionate as myself. Thus, when these results appeared, we put our heads together, and began the process of writing another manuscript, comparing the different factors that led to these results. This will help other researchers move this field ahead. This paper is yet to be submitted but it does suggest that leukocyte concentration is important. We have also submitted a grant to investigate some of these factors in a systematic and controlled manner. Hopefully that study, if accepted, will clarify if a) if the leukocyte concentration is important, b) if platelet count is important, or c) if a combination of the above is leading to better results.
Illuminaries in the field, such as Dr Chris Centeno, have for years blogged about the importance of platelet count. Given that the facet joints in the neck can only ‘hold’ a very limited volume, the concentration of PRP appears to be vital. Whether leukocyte concentration is as important remains to be seen?
Until then, we will continue providing PRP to people with chronic whiplash symptoms as per our original case series, using the proprietary technique and associated rehabilitation that proved so promising in the first place. However, we will be more cautious in recommending PRP for idiopathic neck pain, until we hear more on this matter!
References:
David J. Allison, Sanam Ebrahimzadeh, Stephanie Muise, Steven Joseph, Alexandria Roa Agudelo, Arden Lawson, Nicole Billias, John Tran, Ashley Smith, Eldon Loh. Intra-articular corticosteroid injections versus platelet-rich plasma as a treatment for cervical facetogenic pain: a randomized clinical trial.
Reg Anaesth & Pain Med. 2024; doi: 10.1136/rapm-2024-105889
Marx RE. Platelet-rich plasma: evidence to support its use. J Oral Maxillofac Surg. 2004 Apr;62(4):489-96. doi: 10.1016/j.joms.2003.12.003. PMID: 15085519
Smith A, Andruski B, Deng G, Burnham R. Cervical Facet Joint Platelet-Rich Plasma in People With Chronic Whiplash-Associated Disorders: A Prospective Case Series of Short-Term Outcomes. Int Pain Med Volume 1, Issue 2. June 2022, 100078 https://doi.org/10.1016/j.inpm.2022.100078
Smith A, Andruski B, Deng G, Burnham R. Cervical Facet Joint Platelet-Rich Plasma in People With Chronic Whiplash-Associated Disorders: A Prospective Case Series of Longer-Term 6- and 12- Month Outcomes. Int Pain Med Volume 2, Issue 1, 27 February 2023, 100237 https://doi.org/10.1016/j.inpm.2023.100237
