Instrument Assisted Soft Tissue Manipulation (IASTM) is a popular intervention in the pain & rehab field that involves placing an external instrument (often metallic) on the skin of a patient and repeatedly scraping the area of tissue. IASTM isn’t new and has roots in East Asian medicine with the technique known as Gua Sha. Although the implements have been updated over the years, the premise remains the same: expel blood “stasis”. The traditional thinking is to treat perceived issues caused by “bad blood” by inducing petechiae and ecchymosis, improving blood “stasis” and bringing in “new blood”. Early on, Gua Sha was advertised to treat a variety of issues from pain, colds/flu, respiratory problems (asthma, bronchitis), musculoskeletal issues, and other internal organ-related problems.
More recently, the focus has shifted to musculoskeletal issues and pain. The narratives to validate IASTM continue to be pseudoscientific explanations surrounding the inflammatory process. Often the claims are made IASTM will free “adhesions” and “scar tissue” left behind by a faulty post-traumatic inflammatory process. Proponents argue IASTM “...increases blood and nutrient supply, and migration of fibroblasts to the site of injury. New collagen synthesis and realignment would assist with regeneration of the injured tissue.” Although such claims sound physiologically plausible, the evidence needs to be assessed to see a) whether adhesions and scar tissue actually exist in the scenarios being described, b) if so, whether these are problematic and c) if so, whether they can be affected by IASTM in a clinically meaningful way. Furthermore, IASTM has become popular amongst athletes as a performance and “recovery” aid pre/post training sessions with little regard whether the evidence is supportive for such uses. There exist two previous reviews on this topic:
In 2016, Cheatham et al. stated IASTM lacked efficacy for certain musculoskeletal issues. The authors discussed the gap between current research and clinical practice, stating: “The current evidence seems to lack the methodological rigours necessary to validate the efficacy of IASTM itself or any of the IASTM protocols.” 
In 2017, Lambert et al released a more recent review which included some of the same articles from Cheatham et al’s review. Oddly, Lambert concluded, “The results of the studies included in this review suggest that IASTM is an effective treatment intervention for reducing pain and improving function in less than a three-month period.” 
Nazari et al. argue that these two previous reviews, although adding to the body of evidence (or lack thereof) regarding IASTM, have limitations:
Over reliance on p -values leading to the lack of assessment of the magnitude of treatment effects (clinical significance)
Lack of assessment for risk of bias
No grading of the quality of evidence
No included studies on healthy or athletic populations
The authors conducted the recent review in hopes of solving some of these prior
methodological issues and determine the validity of IASTM for patients and healthy
The authors compiled articles that met the following inclusion criteria:
Randomized controlled trials
Included subjects: healthy, athletes, and those dealing with spinal and extremity conditions
Interventions: any IASTM compared to sham/placebo, control (no treatment), or active treatment
A total of six outcome areas were assessed: pain, disability/function, ROM, muscle
strength, pressure sensitivity, and muscle performance. The authors also established Minimally Clinically Important Differences (MCID) for each outcome assessment (see table). Recall that MCID is different from statistical significance in that it tells us the smallest change in a treatment outcome that a patient would view as meaningful in their case management. So if an intervention produces an effect below the MCID, it would be considered not clinically significant.
Finally, the GRADE system and Cochrane Risk of Bias tool were used to assess the quality and bias of each included study respectively.
20 RCTs, published between 2000 - 2018, were included in the review. A variety of IASTM tools were studied: Graston, SASTM, HawkGrip, Ergon, FAT, Técnica, Gavilán,
Astym, EDGE, and AdvantEDGE.
Examining the risk of bias of the included studies (see Risk of Bias table), overall the included studies were all considered at high risk of bias. Two of the 20 trials were actually
pre-registered. Pre-registration of trials is important because it helps mitigate publication bias, where the outcome of a study influences whether the study is published. Fourteen of the 20 studies failed to assess for adverse events due to the intervention. Assessing adverse events is important in order to adequately weight risk vs benefits for treatment selection and its effects on prognosis of a patient case. Three of the 20 studies were published in predatory journals. These journals often lack the same standard and prestige of other journals by lacking the rigors of usual peer-review and merely requiring a financial payment to entry for
Twelve studies failed to disclose funding sources which means the research could be biased for positive findings in order to promote the person/company/product providing financial aid.
Finally, nine trials didn’t disclose whether there were any sources of conflicts.
10 trials compared IASTM plus other treatment vs other treatment
8 trials compared IASTM with control (no treatment)
5 trials compared IASTM with other treatment
2 trials compared IASTM plus other treatment with placebo/sham other treatment
Other treatments included exercise (stretching, strengthening, and balance), manual soft tissue mobilization, foam rolling, rehab programs, education, cycling/treadmill walking, or compressive myofascial release.
The overall quality of included studies is very low with high risk of bias.
From the 20 included RCTS, 86 outcomes were reported; 73 of those outcomes showed no difference between the groups with or without IASTM. Put another way: IASTM was not demonstrated as beneficial for these 73 outcomes. The other 13 outcomes are questionable at best or in favor of other treatment(s). Three outcomes favored IASTM (two range of motion and one function) by a clinically meaningful difference, however, the authors conclude more data is needed due to the
...given the predefined MCID scores, the 95% CIs did not exclude the MCID scores, therefore, more data is required to make a definitive conclusion.
Eight outcomes (pain, range of motion, and pressure sensitivity) supported IASTM but the studies were published in suspected predatory journals and rated as very low-quality evidence with high risk of bias. Two outcomes (range of motion and function) showed clinically meaningful support for other treatment groups (lacking IASTM).
The following forest plots display standardized means of the data. Forest plots are a
great way to observe review results from included studies in a graphical representation. Standardized means are utilized when the same outcome variable is assessed with various tools across studies.
Figure 4. Forest plot of comparison: Instrument-assisted Soft Tissue Mobilisation (ISTM) plus other treatment (tx) vs other treatment (tx). Standardized mean differences. Outcomes: Function (0 – 100), Pain (0 – 100), Range of Motion (¡) and Grip strength (kg).
Figure 6. Forest plot of comparison: Instrument-assisted Soft Tissue Mobilisation (ISTM) vs no treatment (tx). Standardized mean differences. Outcomes: Pressure sensitivity (kg/cm2), Pain (0 – 100), Range of Motion (°) and Muscle performance (cm, Watts, m/sec).
Figure 8. Forest plot of comparison: Instrument-assisted Soft Tissue Mobilisation (ISTM) vs other treatment (tx). Standardized mean differences. Outcomes: Function (0 – 100), Pain, Range of Motion (°) and Grip strength (kg).
Figure 10. Forest plot of comparison: Instrument-assisted Soft Tissue Mobilisation (ISTM) with/without other treatment vs placebo/sham. Standardized mean differences. Outcomes: Function (0 – 100), Pain (0 – 100) and Range of Motion (°).
Based on the above, there is an underwhelming show of support for IASTM. This
information, coupled with the other 73 outcomes showing no benefit via IASTM -
support at this time is greatly lacking to utilize the intervention for patients, healthy
populations, or athletes. The authors state [emphasis ours]:
The current evidence does not support the use of IASTM as an effective treatment to improve participant/patient outcomes, since all the included trials were very low quality, and three trials were published in suspected predatory journals.
Why does this matter?
Often the popularity of an intervention rapidly grows and becomes accepted as the “norm” for usage in clinical practice well before research has been conducted, or in this case - despite what the evidence is demonstrating. To this point the authors state,
The evidence is in conflict with the uptake of the intervention in practice. For example, the Graston website reports that more than 30,000 clinicians have been trained, 14,000 instrument sets have been sold and 2,500+ workshops have been provided. Since this represents the uptake form only one of the instrument providers, the potential gap between evidence and implementation is high.
Even the narratives supplied to validate IASTM are not well supported. Clinicians cite the use of IASTM for pain, performance, myofascial trigger points, scar tissue,
adhesions, and inflammation. However, these explanations of physiological effects and proposed mechanisms for improving function while decreasing pain remain
unsubstantiated in the research literature, as demonstrated by this recent review.
The way this process should work in clinical practice -
Step 1 - Conjecture - does an issue actually exist beyond conjecture (example: myofascial trigger points). If existence can’t be established then there is little need to assess the effectiveness or efficacy of an intervention.
Step 2 - Define Terms - once we’ve agreed an issue exists, we need to define the issue (diagnostic criteria). More importantly, we need to determine the existence of the issue is pathological and warrants intervention otherwise prognosis will be negatively affected.
Step 3 - Quality & Justification - after we’ve agreed the issue exists and is pathological, then we need to assess if we can make an impact. If we are capable of affecting the issue, then the risks vs. benefits of treatment(s) needs to be weighted.
And yet, the usage of IASTM has already jumped to the final step before the narratives given for its use have been validated. Regardless, Nazari has demonstrated IASTM greatly lacks support based on the totality of evidence at this time. Reviews such as this are paramount for guiding clinical decision making and ensuring we are not unnecessarily conditioning patients to false narratives and treatments. We need to move on from this intervention and cease trying to scrape the bottom of the barrel for supportive evidence - it doesn’t exist at this time.
Nazari G, Bobos P, MacDermid JC, Birmingham T. The Effectiveness of Instrument-Assisted Soft Tissue Mobilization in Athletes, Healthy Participants and Individuals with Upper/Lower Extremity and Spinal Conditions. A Systematic Review. Archives of physical medicine and rehabilitation. 2019.
Cheatham SW, Lee M, Cain M, Baker R. The efficacy of instrument assisted soft tissue mobilization: a systematic review. The Journal of the Canadian Chiropractic Association. 2016; 60(3):200-211.
Lambert M, Hitchcock R, Lavallee K, et al. The effects of instrument-assisted soft tissue mobilization compared to other interventions on pain and function: a systematic review Physical Therapy Reviews. 2017; 22(1-2):76-85.