The scientific literature regarding the use of platelet-rich plasma (PRP) injections for the treatment of spine pain conditions is in its infantile stage. There are limited studies assessing the efficacy of PRP for the treatment of discogenic low back pain (degenerated disc or disc injury), facet joint pain (otherwise known as zygapophyseal joint pain or z-joint pain), or sacroiliac joint pain (intra-articular joint pain or pain emanating from the supportive ligaments). While PRP is proposed to enhance the body’s natural wound healing mechanisms, it is not apparent from human studies that the tissue objectively “regenerates”. In other words, if one were to complete an MRI of an individual’s spine prior to PRP treatment, followed by an MRI a year later, it is unlikely that clear evidence of degeneration reversal will be evident. Rather, the changes are more subtle, occurring at a cellular level.
In the spine, just like the other joints of the body, there is a delicate balance between degeneration processes and regeneration processes. As we get older, degeneration tends to outweigh regeneration and we begin to degrade (we develop osteoarthritis). The function of regenerative cells (e.g. fibroblasts and chondrocytes) start to lose their battle with degenerative enzymes (e.g. metalloproteinases). Similarly, growth factors that promote healing, such as TGF-beta, IGF-1, and BMP-2, are produced in insufficient quantity to counteract cytokines, such as interleukin-1, TNF-alpha, and others. By boosting the body’s natural heat-healing mechanisms, this delicate balance is gently pushed back in the other direction, slowing the degenerative process. How this helps with “pain” is not completely understood.
Although there is incomplete knowledge of how PRP helps spine pain conditions, there is a trend in the early literature for benefit. It appears as though a good percentage of patients will benefit. The benefits tend to be incomplete (partial relief), but significant. The benefits tend to kick in at around one month post-injection. The benefits maximize at three months pos-tinjection. The benefit tends to last from three months through 6 and 12 months, in early studies.
Discogenic Low Back Pain: Four early studies in the treatment of discogenic low back pain are worth review:
- Akeda K, et al. Intradiscal injection of autologous platelet-rich Plasma releasate to treat discogenic low back pain: A preliminary clinical trial. Asian Spine J 2017;11(3):380-389.
- Levi D, Horn S, Tyszko S, et al. Intradiscal platelet-rich plasma injection for chronic discogenic low back pain: preliminary results from a prospective trial. Pain Med. 2016;17(6):1010–1022.
- Tuakli-Wosornu YA, Terry A, Boachie-Adjei K, et al. Lumbar intradiskal platelet-rich plasma (PrP) injections: a prospective, double-blind, randomized controlled study. PMR. 2016;8(1):1–10.
- Navani A, Hames A. Platelet-rich plasma injections for lumbar discogenic pain: a preliminary assessment of structural and functional changes. Tech Reg Anesth Pain Manag. 2015;19(1-2):38–44.
Akeda et al. treated 14 patients with WBC poor PRP. Patients were followed for one year. Pain intensity improved by greater than 50% at one month with results sustained at one year. Similarly, significant functional improvements were demonstrated at one month, but were more impressive at six months and 12 months. Followup MRI did not show objective evidence of “regeneration”.
Levy et al. published a prospective trial of 22 patients who were treated with WBC rich PRP. All patients followed up at two months. Nineteen out of 22 patients followed up at six months. Greater than 50% pain relief was reported in 32% of patients at two months and 47% of patients at six months.
Tuakli-Wosornu et al. completed a prospective double-blind randomized control study. After recruitment, 18 patients were analyzed in the control group and 29 patients were analyzed in the treatment group. Treatment results were modest. Although statistically significant improvements were shown in pain and function, the improvements were small. For example, there was a greater than 2-point improvement in pain on the numeric rating scale (pain from 1-10) for pain. However, the functional data showed only borderline results.
Facet Joint Pain: Two early studies in the treatment of facet joint pain have been published:
- Wu J. et al. A new technique for the treatment of lumbar facet joint syndrome using intra-articular injection with autologous platelet rich plasma. Pain Physician 2016; 19:617-625.
- Wu J. et al. A prospective study comparing platelet-rich plasma and local anesthetic (LA)/corticosteroid in intra-articular injection for the treatment of lumbar facet joint syndrome. Pain Practice 2017; 17(7):914–924.
Wu et al. published a prospective study of 19 patients treated for facet joint “syndrome” with x-ray guided PRP. The biggest fault of this study is that the diagnosis was made based upon clinical assessment (history, physical examination, and radiological imaging), not validated diagnostic blocks. Therefore, it is possible that these individuals had low back pain of a different source. It may be reasonable to assume that this group of studied patients had “mechanical low back pain of unclarified etiology”. Regardless, these patients were treated with PRP for presumed facet joint pain. Clear benefits were shown at one month, with benefits sustained at two months and three months. The degree of improvement in pain was approximately 50%. The degree of improvement in function and quality of life was also approximately 50%. The satisfaction rate was high.
Another study by Wu et al. was a comparison study between platelet-rich plasma and local anaesthetic. One group received intra-articular PRP and the other group received intra-articular local anaesthetic and corticosteroid. Followup took place at one, two, three, and six months. Although diagnostic injections were used in this group, they were not performed in standardized fashion. As well, the PRP group was compared to a corticosteroid group that received a very low dose of corticosteroid. Therefore, it is not clear whether the PRP was compared to local anaesthetic and steroid or local anaesthetic and “placebo”.
With the shortcomings of the Wu et al. study accepted, the results of both groups could be compared. The local anaesthetic and corticosteroid group and the PRP group demonstrated improvements at one week and one month. The improvements with the corticosteroid group began to regress after that. The PRP benefits improved from one month to two months and three months and the results were sustained at six months. This is true for both pain and function. Similar to the previous study by Wu et al. described above the degree of improvement for both pain and function was greater than 50%.
Sacroiliac Joint Pain: Two early studies for the treatment of sacroiliac joint pain are worth mention:
- Singla V, Batra YK, Bharti N, et al: Steroid vs. platelet-rich plasma in ultrasound-guided sacroiliac joint injection for chronic low back pain. Pain Practice 2017;17:782–91.
- Wallace P, Wallace LB, Tamura S, et al. Effectiveness of ultrasound-guided platelet-rich plasma injections in relieving sacroiliac joint dysfunction. American Journal of Physical Medicine & Rehabilitation. August 2020; 99(8) 689-93.
Singla et al. performed ultrasound-guided sacroiliac joint injections based upon the clinical assessment (diagnostic injections were not used to confirm the diagnosis). The PRP concentrate was leukocyte poor or leukocyte free. The results were similar to the facet joint studies. Individuals who received corticosteroids achieved short-term relief. Individuals who received PRP demonstrated early results that were modest at two weeks, but more impressive at four and six weeks. Improvements were maintained at three months. Once again, improvements in both pain and function were demonstrated at three months.
Recently, Wallace et al. published a study on ultrasound-guided platelet-rich plasma injections. In a study of 50 patients, the trend for early modest improvements at two weeks and four weeks with more substantial improvements at three months and beyond was once again demonstrated. The patients in this study did well from four weeks through six months with the most consistent results shown from three months to six months.
Overall Impression of PRP for Mechanical Low Back Pain from the Intervertebral Discs, Lumbar Facet Joints, & Sacroiliac Joints:
In general, it is reasonable to say that early studies for the treatment of mechanical low back pain using PRP are flawed. In many instances, confirmation of the anatomical source of pain was based upon clinical assessment, rather than validated image-guided diagnostic injections. That being said, despite these shortcomings, there is a strong trend from study to study. Patients tend to show some degree of improvement at four weeks post-injection and as early as two weeks post-injection. The efficacy of the treatment seems to be established by three months. In the individuals who do respond, treatment success at three months tends to translate to maintained success at six months (and 12 months if studied).
Because PRP is a safe treatment modality, it is reasonable for patients to be optimistic that there is a moderate probability of partial relief of their back pain condition, which will be most evident at three months and hopefully will be sustained (if they are a responder) for at least six months.