Shockwave Therapy for Spasticity After Stroke or Other Upper Motor Neuron Injury: What a 2022 Meta-Analysis Found

Spasticity can be one of the most frustrating long-term effects after an upper motor neuron injury (like stroke, traumatic brain injury, spinal cord injury, or other neurologic conditions). Muscles can feel tight, resistant to movement, and difficult to stretch, which can limit function, comfort, and range of motion.

A 2022 systematic review and meta-analysis looked at whether extracorporeal shock wave therapy (ESWT) can help reduce spasticity and improve joint mobility, and how safe it appears to be.

Here's the breakdown.

What is spasticity (in plain terms)?

Spasticity is increased muscle tone caused by disrupted signals from the brain/spinal cord to the muscles. It often shows up as:

• Stiffness or tightness that makes movement harder

• Resistance when a clinician moves a limb passively

• Reduced joint range of motion over time

• Pain, cramping, or difficulty with daily tasks (walking, dressing, hygiene)

Because spasticity can be persistent, clinicians often use a mix of rehab strategies: stretching, strengthening, bracing, medications, injections, and other modalities.

Why would ESWT be considered for spasticity?

ESWT is best known in musculoskeletal care, but it's increasingly studied in neuro-rehab.

Researchers are interested in ESWT because it may influence the muscle and connective tissue environment (and possibly neuromuscular signaling) in ways that reduce hypertonicity and improve movement. The exact mechanisms are still being studied, but the clinical question is straightforward:

Does ESWT measurably reduce spasticity and improve range of motion?

The study at a glance

Zhang and colleagues conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of ESWT for spasticity after upper motor neuron injury.

What did they do?

• Searched 8 electronic databases from inception through August 3, 2021

• Two independent reviewers handled screening, data extraction, and risk-of-bias assessment

• Meta-analysis performed using RevMan and R

How much evidence did they include?

• 42 studies total

• 1973 patients across eligible studies

• 34 studies included in the meta-analysis

• Studies were published between 2010 and 2021

What outcomes did they look at?

Two key outcomes were emphasized:

1. Spasticity severity using the Modified Ashworth Scale (MAS)

2. Passive range of motion (PROM) of the affected joint

Quick definitions

• Modified Ashworth Scale (MAS): a common clinical scale used to rate resistance to passive movement (a proxy for spasticity). Lower scores generally mean less spasticity.

• Passive range of motion (PROM): how far a joint can move when someone else moves it (not the patient actively). Improvements can matter for function, comfort, and preventing contracture.

What they found

1) ESWT reduced spasticity scores

Compared with other interventions, ESWT significantly decreased MAS scores.

Translation: across the pooled evidence, people receiving ESWT tended to show less resistance/tone on clinical spasticity testing.

2) ESWT improved passive range of motion

ESWT also significantly increased PROM.

Translation: joints tended to move more freely after treatment, which can support rehab goals like gait training, upper-limb function, and daily care.

What about safety?

Overall, ESWT appeared generally safe in the included studies.

A small number of studies reported mild adverse effects, including:

• Skin injury

• Bone distortion

• Muscle numbness

• Pain

• Petechiae (small red/purple spots)

• Weakness

Important nuance: these were described as slight adverse effects and were reported in five studies.

The biggest caveat: study quality and heterogeneity

Even though the pooled results were positive, the authors emphasized a key limitation:

• Many included studies had poor methodological quality

• There was high heterogeneity (meaning protocols, populations, and study designs varied a lot)

Translation: the overall conclusion is promising, but we still need better-designed trials to know:

• Which patient groups benefit most

• Best treatment parameters (energy, frequency, number of sessions, target muscles)

• How long benefits last

• How ESWT compares head-to-head with other standard spasticity treatments

The HyperWave takeaway

This 2022 meta-analysis suggests ESWT may offer meaningful clinical value in neuro-rehab:

• Reduced spasticity (lower MAS scores)

• Improved joint mobility (higher PROM)

• Generally mild side effects when reported

If you're exploring options for post-stroke or neurologic spasticity, ESWT may be a useful adjunct to a broader rehab plan.

Full citation

Zhang HL, Jin RJ, Guan L, Zhong DL, Li YX, Liu XB, Xiao QW, Xiao XL, Li J. Extracorporeal Shock Wave Therapy on Spasticity After Upper Motor Neuron Injury: A Systematic Review and Meta-analysis. Am J Phys Med Rehabil. 2022 Jul 1;101(7):615-623. doi: 10.1097/PHM.0000000000001977. Epub 2022 Feb 15. PMID: 35152251; PMCID: PMC9197142.

Educational content only. This article is not medical advice. If you have spasticity after neurologic injury, consult a qualified clinician for diagnosis and a personalized treatment plan.