Prolotherapy (also called ligament sclerotherapy) is an injection-based treatment for chronic musculoskeletal pain
- proposed mode of action is the reduction of joint instability through the strengthening of stretched or torn ligaments
- most common application in the back is chronic non-specific low-back pain that has not responded to other therapies. Protocols for prolotherapy for back pain in scientific studies to date vary, but all include the injection of an irritant (proliferant) solution into ligaments and tendinous attachments at weekly or fortnightly intervals for three to eight treatments
Mechanism of action:
Proponents of prolotherapy believe that ligament injections trigger an influx of granulocytes, macrophages and fibroblasts, the release of growth factors and ultimately, collagen deposition
- hypothesise that this leads to strengthening of ligaments and a reduction in pain and disability
- three major classes of proliferants commonly used in prolotherapy
- the irritants
- irritants act by either damaging cells directly or by rendering the cells antigenic through alteration of surface proteins
- include phenol, guaiacol and tannic acid
- another category of irritants called particulates, exemplified by pumice flour
- act by triggering cellular trauma following injection into target tissues, and by directly attracting macrophages, which ingest them and secrete polypeptide growth factors
- the chemotactics
- chemotactics also act by attracting inflammatory cells. The only agent in this class is sodium morrhuate.
- the osmotics
- includes concentrated solutions of glucose, glycerin and zinc sulphate. They act by causing an osmotic shock to cells leading to the release of pro-inflammatory substances
- there is some overlap in their purported actions
- local anaesthetic (commonly lignocaine) is often added to proliferant solutions to reduce the pain of the irritant injections
- an increase in mass and thickness in animal and human ligaments has been demonstrated in response to repeated injections of a commonly used solution containing glucose (dextrose), glycerine, phenol and lignocaine (lidocaine) (1)
Effectiveness of prolotherapy:
A systematic review regarding prolotherapy for chronic lower back pain concluded (1) "...There is conflicting evidence regarding the efficacy of prolotherapy injections for patients with chronic low-back pain. When used alone, prolotherapy is not an effective treatment for chronic low-back pain. When combined with spinal manipulation, exercise, and other co-interventions, prolotherapy may improve chronic low-back pain and disability. Conclusions are confounded by clinical heterogeneity amongst studies and by the presence of co-interventions..."
A more recent study comparing use of corticosteroid injection therapy with prolotherapy for tennis elbow concluded (2) "..both prolotherapy and corticosteroid therapy were generally well tolerated and appeared to provide benefit of long duration. Small sample size precludes determining whether one therapy is superior to the other. Larger, controlled trials appear feasible and warranted on the basis of these findings..."
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