How Ultrasound Therapy Prioritizes Safety? Understanding Potential Dangers and Side Effects

Physiotherapists, doctors, or patients, are you seeking accurate information about ultrasound therapy used by physical therapists? Specifically, what are the possible side effects, is there any danger in using them in a certain way?

Are there precautions to be taken or a maximum intensity to be observed? Which devices pose the least risk?

As a physiotherapist myself, I will provide an update on what we know in 2023 regarding these questions. To write this blog post, I rely on:

• My experience as a employed and independent physiotherapist.
• In-depth literature research in international scientific publications (all references and research methodology provided at the end of the article).

Feel free to leave your questions in the comments section!

How do ultrasound therapy work?

Ultrasounds have been used in many different sectors since their discovery in the 18th century. For example, they are utilized in various industries, cooking, cleaning, and medicine.

Because an ultrasound is primarily a mechanical wave that propagates through gases (like air) or fluids (like blood) and even solids (like the skin).

In medicine, they are used for diagnosing and treating certain diseases. They have also been specifically used in physiotherapy sessions since the 1960s.

The potential effects of ultrasound in physiotherapy have been studied since…1966! That’s when the publication “Ultrasound in physiotherapy” was released. Since then, there has been an increasing number of academic publications on the subject, particularly since the 2000s.

Here’s how ultrasound therapy, practiced by physiotherapists, theoretically works:

1. The therapist turns on the machine.
2. They apply a conductive gel to the area of the body being treated.
3. They move the ultrasound probe over a specific part of the body.
4. The ultrasound emits an ultrasonic signal that has both mechanical and thermal effects.
5. The ultrasound penetrates the different tissues to varying depths (depending on the frequency and intensity settings). This theoretically causes a defibrillating, analgesic, and anti-inflammatory effect.
6. After a few minutes, the treatment is complete.

Note that this can also be done by people themselves. There are devices designed for personal use.

The specific role of physiotherapists is not to apply the technique, but rather to guide you towards the most appropriate ones for your needs.

Do we have a lot of data on the side effects of ultrasound therapy?

Definitely, yes! In fact, it’s one of the techniques employed by physiotherapists that has the most data:

• It has been practiced since the 1960s.
• There are hundreds of academic publications on the subject.
• It’s relatively easy to evaluate the benefits and side effects of this technique compared to others in physiotherapy because it’s possible to easily create a placebo for ultrasound (applying the probe without turning on the device!). This has actually been done in clinical studies.

You’ll see that we have quite a lot of knowledge about the short-term side effects of ultrasounds. Quite a lot, especially compared to many other methods or devices used in physiotherapy!

What are the side effects of ultrasound therapy?

Clinical studies conducted on patients allow us to list when secondary events occur, how frequently they occur, and sometimes even how long they last.

Here’s what the studies that evaluated the potential side effects of ultrasound therapy tell us:

Side Effects	Frequency of side effect	Study
Skin reactions	11/73. Only one patient had to stop treatment due to skin reactions	Oakland 1993
Burns	?? Theoretical risk	Miller 2012
None	None	Kim 2019
No specific details	14/232 experienced a side effect, including 3 with a severe side effect, but a similar number in the placebo group! And the effects were not attributed to the treatment	Licciardone 2013
None	None during or after treatment	Ulus 2012
None	None during or after treatment	Bartkowiak 2019
None	None	Zhang 2016

⚠️ When ultrasounds are used for other purposes (for example, treating bladder stones or tumors), other side effects may be described. However, different types of ultrasounds are used (or rather, not at the same frequency, intensity, or duration). So, it’s important to make a distinction.

One caveat: most studies do not report the side effects that occur during or after the sessions. Here’s what a Cochrane review tells us about this:

Only one study (on ultrasound for low back pain) measured adverse events after treatment and reported a total of 7/118 (5.9%) adverse events in the ultrasound group and 4/107 (3.7%) events in the placebo group (Licciardone 2013). Three of these events (two in the ultrasound group, one in the placebo group) were considered serious adverse events; however, none of the reported adverse events were determined to be related to the intervention.

Cochrane, 2020

In my opinion, it is more reasonable to assume that there are no other serious side effects associated with the use of ultrasound therapy, considering how frequently they are used daily for decades without case studies supporting other types of adverse effects.

It is rare for side effects to occur with ultrasound therapy. When they do, they are mostly skin reactions or, occasionally, gastrointestinal disturbances.

Pain after ultrasound therapy

Pain after ultrasound therapy can occur for various reasons and can differ depending on the specific circumstances, including pregnancy. Here are some possible explanations:

1. Heating effect: Ultrasound therapy can generate heat in the tissues being treated. While this is typically controlled and kept within a safe range, excessive heat or prolonged exposure to ultrasound can potentially cause discomfort or pain.
2. Tissue irritation: The application of the ultrasound probe on the skin can sometimes lead to skin irritation or sensitivity.
3. Treatment intensity: If the intensity is too high or the duration of the treatment is prolonged, it may lead to increased post-treatment discomfort and sore.

Pain is uncommon after ultrasound therapy. Especially since they are often used with the intention of relieving pain!

Is there any danger in using ultrasound therapy?

In principle, the major risks you expose yourself to are the possibility of experiencing skin reactions or digestive disturbances during the session. However, these occurrences are extremely rare.

If you would like to hear about my professional experience, in addition to everything else: I have had limited personal experience using ultrasound therapy as a physiotherapist, but I have observed many colleagues using it over the past 10 years. I have never witnessed any adverse effects other than occasional skin reactions like redness, but that is the exception rather than the rule. Some individuals may also dislike the sensation (particularly due to the gel) and may choose to stop the treatment, but that is not truly a “side effect”!

To summarize: There is likely less danger in using ultrasound therapy than in crossing a crosswalk (although crossing a crosswalk may be more useful 😉).

What are the contraindications of ultrasound therapy?

There is a fairly extensive list of contraindications for the use of ultrasound therapy. This list is included in all the instructions accompanying the devices.

Some of these contraindications are precautionary measures: it is uncertain whether the use of ultrasound therapy would be harmful in these cases, but it is still recommended to avoid using it. A typical example of a precautionary contraindication is the application of ultrasound therapy on pregnant women (in the abdominal or lower back area, near the fetus).

For example, you may come across sources that contraindicate ultrasound therapy in cases of knee replacement or hip replacement, although this is not a consensus.

Here are the main contraindications for ultrasound therapy in physiotherapy:

• You have a “serious” injury or health problem in the area where you wish to apply ultrasound therapy, such as a malignant tumor, infection, open wound, skin condition like eczema, or vascular problem.
• You have a pacemaker or defibrillator: ultrasound therapy should not be applied in that area.
• You have deep vein thrombosis (which is rarely unnoticed).

Ultrasound therapy is primarily contraindicated in cases of injury, medical devices or health issues in the area to be treated, or deep vein thrombosis.

Are some ultrasound devices less risky than others?

In general, you will find two main types of ultrasound devices:

1. Portable devices: These are primarily intended for home use by individuals (but sometimes also used by physiotherapists). Generally, they have lower frequency and power. However, this does not necessarily mean they are less effective.
2. Fixed devices: These devices are designed for professional use and are typically used by healthcare professionals such as physiotherapists. They are more powerful and offer a wider range of settings and options for therapeutic ultrasound applications.

I have already given my opinion as a physiotherapist on the Revitive ultrasound device.

Please note that, in all cases, for these devices to be marketed in European Community (even online), they must comply with the same rules of conformity and safety to obtain the famous CE marking (European Community).

The ultrasound device and Intellect ultrasound heads are listed on the National Agency for the Safety of Medicines and Health Products (ANSM, France) as Class IIb medical devices. These are devices with a high or significant potential risk. However, it should be noted that devices such as male condoms or contact lens disinfection products are also included in this class.

The Revitive ultrasound device is also listed on this list. It is classified as a Class IIa medical device, which is the same class as blood pressure monitors and thermometers. These are devices with a moderate or measured potential risk.

Not all ultrasound devices are classified in the same risk category by the ANSM. However, as we have seen before, adverse effects are rare regardless of their risk class.

See on Amazon example of home ultrasound therapy device.

What is the risk-benefits balance of using ultrasound therapy?

You have seen that the side effects of ultrasound therapy in physiotherapy are very rare and generally not serious. The risk of using them is therefore almost negligible. Just be attentive during and after the session: if you experience any skin or other reactions like pain, discuss them with your physiotherapist.

But are ultrasound therapies effective? What’s the point of turning to a device, even if it’s considered safe, if its effectiveness is highly doubted?

And that’s the heart of the problem. I plan to write a specific blog post on the effectiveness of ultrasound therapy in physiotherapy. In the meantime, let me share the words of research teams who have extensively investigated the subject:

The clinical benefit for patients of ultrasound treatments in physiotherapy remains uncertain.

Miller 2012

Ultrasound therapy makes little to no difference in terms of pain and well-being compared to a placebo.

Cochrane 2020

Our results are in line with previous researchers who found that ultrasound therapy was ineffective in treating this condition (plantar fasciitis).

Katzap 2018

You may have seen advertisements on your TV screen, in your favorite magazine, or on a website claiming that devices like Revitive Ultrasound Therapy “accelerate the healing of muscle injuries” while “relieving pain.” However, there is no clinical study supporting these claims.

Not only do we lack empirical evidence that ultrasound therapy “accelerates the healing of injuries,” but even from a theoretical standpoint, it seems unreasonable to expect significant effectiveness in accelerating healing or providing significant pain relief from a device that only needs to be applied for a few minutes a day, or even less.

Injuries and pain are complex, multifactorial phenomena. They are not simply damaged tissues that can be “repaired” or “treated.”

But I will delve deeper into all of this in an upcoming blog post. In the meantime, be reassured that you are taking minimal risks if you choose to use ultrasound therapy. 😌