Nerve Entrapments and US Guided Hydrodissection

Ultrasound-Guided Hydrodissection for Nerve Entrapments

Ultrasound-guided Hydrodissection is one of the newest methods that is being used to treat patients with entrapped nerves. The so-called entrapment neuropathy of the peripheral nerves is fairly common but is vastly unrecognized as the main source of pain.


For those who aren't doctors, nerves need to glide smoothly around your body's surrounding tissue. However, when they get entrapped, it means that the nerves are stuck or they have adhered to the surrounding tissue. The stretching and compression of the nerve in this scenario result in pain.


It isn't entirely uncommon for nerves to be entrapped by trauma or scar tissue left behind after a surgery or an issue with surrounding anatomic structures. The most common symptoms of the condition include primarily achiness, burning or shooting pain, or numbness.


While some doctors in the past may have recommended surgery, nerve Hydrodissection, as it is called, is now being used as an alternative. The procedure uses ultrasound guidance. The doctor identifies the entrapped nerve using ultrasound and then glides the needle to it. Once the needle tip reaches the nerve, a fluid is injected to free it from the surrounding scar tissue. It can and often does have the same remarkable effect as surgical release, resolving tingling, numbness, and chronic pain.


The conditions best treated using Hydrodissection include Carpal Tunnel Syndrome, the most common entrapment neuropathy, which is common in the general population. It accounts for 90% of the recognized nerve entrapments. However, as stated above, most of the other entrapments are underdiagnosed or unrecognized as the cause of chronic pain.


Why Use Ultrasounds?

Over the past decade or so, ultrasound resolution has improved greatly to the point where it can be used for highly accurate diagnoses of problems in very small structures such as nerves. Ultrasound not only can see the smallest nerves in the body but can determine abnormalities inside the nerve as well as visualize scar tissue that may be entrapping the nerve. In addition, since ultrasound is performed in real-time, meaning while the person is moving the limb or body part, dynamic entrapment can also be seen. Because of this, ultrasound has been used to create many different novel procedures which save time and effort while being just as effective, as for instance, surgery.


One of the now growing areas of musculoskeletal treatment using ultrasound to take advantage of this technology is treating what's called entrapped nerves. Ultrasound can initially be used to diagnose the problem and then used as a tool to treat it. There are many issues that ultrasound guidedHydrodissection, for instance, can treat that would otherwise require surgery. Most of all, Hydrodissection is a lot safer, and there is limited downtime involved, which means that the person treated can go back to work soon after. That is something often delayed with surgery.


How Does US Guided Hydrodissection Work?

Nerve Hydrodissectionis a technique used to treat nerve entrapments. As discussed earlier, it entails injecting an anesthetic and then additional fluid which is mainly used to separate the entrapped nerve from the surrounding scar or tissue.


Over the years, animal models have suggested that minimal compression can translate to perpetual neuropathic pain. However, the mechanical benefits associated with using Hydrodissection include releasing the nerve compression.


The pathologic nerves that are causing the pain can easily be identified using ultrasound visualization. Hydrodissection is one of the safest methods.

Nerve Entrapments and US Guided Hydrodissection

Conditions that Can be treated using Hydrodissection

It really goes without saying that nerve entrapment can affect any one of the peripheral nerves. However, some of the most common conditions that can be treated using Hydrodissection include:

  • CarpalCarpel Tunnel Syndrome or CTS

  • Pronator Teres Syndrome

  • Radial nerve entrapment or posterior interosseous nerve entrapment

  • Piriformis syndrome

  • Cubital Tunnel Syndrome

  • Peroneal Nerve entrapment

  • Morton's neuroma

  • Meralgia Paresthetica

Having said that, scar neuropathy in any peripheral nerve including the nerves in the groin, perineum, and buttock as well as the hands and feet can all be treated with ultrasound-guided hydrodissection.


How Many Treatment Sessions Are Needed To Relieve Pain?

It mainly depends on the nature of the condition that needs to be treated. Generally, Hydrodissection does not need to be repeated more than once or twice. However, knowing how many treatment sessions are needed is hard to determine without first examining the cause of the pain, which is why visiting a doctor experienced with using Hydrodissection is so essential.


Will Surgery Be Eventually Required?

We acknowledge that there is no getting around the need for surgery in some situations, especially to fix nerve damage. However, Hydrodissection can help save people from getting surgery, especially for conditions like carpal tunnel syndrome (CTS) or other syndromes resulting from nerve entrapment. On the upside, the procedure only takes a few minutes, and there is minimal downtime involved. Also, the risks associated with Hydrodissection are next to none compared to surgery.


Many people fear surgery, and that may prevent them from seeking help. However, with Hydrodissection, you have peace of mind knowing that the condition can be addressed without the need for surgery.


Nerve Entrapments and US Guided Hydrodissection


Recovering From the Procedure

Entrapped nerve hydrodissection, for the most part, is now considered an effective and relatively safe form of treatment. Most patients will notice a significant reduction in the level of pain or numbness they felt before undergoing the procedure.


Complications stemming from Hydrodissection are rare, but there may be some swelling at the injection site and infection in some rare instances. However, most patients will return to their normal activities within a few weeks. That said, some conditions may require multiple sessions depending on how well the procedure before it went and the level of pain being reported.


Patients who continue to experience pain related to nerve entrapment or compression even after having received the injection may eventually require surgery. So, surgery, in this instance, is the last resort.


Final Word

Even though Ultrasound-guided Nerve Hydrodissection is now increasingly common, there is still limited amounts of high-quality data to determine its exact percentage of effectiveness. Much of the research and data available have been derived from retrospective studies and case reports. The evidence thus far successfully demonstrates that the technique is highly effective and offers low to no risk for patients compared to surgery.


Ultrasound is used to decrease the risk of nerve injection and, consequently, injury during the procedure. The use of high-resolution ultrasound means that the technique is much more precise, and there is minimal risk if performed in trained hands.. In fact, studies of Hydrodissection in various sections of anesthesiology literature suggest there is no evidence of adverse effects of an inadvertent nerve injection in the short or long term. Thus the argument stands that Hydrodissection is a safe procedure.

The medical landscape is ever-changing, and with it comes forms of treatment, some of which haven't entirely been studied the way they might have been twenty years ago. However, it takes time for data to be gathered and have compiled across hundreds of studies.


Doctors regularly use ultrasound for musculoskeletal medicine, which may have been unthinkable only a decade or so ago. For this reason, despite Ultrasound-Guided Nerve Hydrodissection being relatively new, with few studies, it is still highly effective. Hundreds if not thousands of patients attest to that fact.

For additional information and further reading on pronator nerve entrapments, read this article:

Delzell, P, Patel, M, Ultrasound-guided perineural injection for pronator syndrome caused by median nerve entrapment, J Ultrasound Med. 2020 May;39(5):1023-1029.