Ultrasound-Guided Nerve Hydro Dissection - Uses, Types, Techniques, and Outcome

Introduction:

In recent times, medical equipment and technologies have been doing very well regarding accessibility and availability. Hence, clinicians have exploited ultrasound's better resolution to boost their methods' accuracy. The new techniques have evolved with the use of musculoskeletal ultrasonography in treating peripheral nerve entrapments, one of the expanding fields that can benefit from this imaging technique. Several common illnesses, including cubital tunnel syndrome (ulnar nerve entrapment results in aching pain, weakness, and numbness inside the elbow) and carpal tunnel syndrome (compression of the median nerve lying deep under the upper limb), have been diagnosed and treated by ultrasound.

What Is Hydrodissection?

Hydrodissection is a minimally invasive, non-surgical treatment in which small amounts of fluid are injected to release a trapped nerve or reduce intraoperative blood losses. The technique involves different solutions, like anesthetics, corticoids, saline, 5 percent dextrose, or platelet-rich plasma (PRP). This is commonly employed in conditions involving compressed nerves, including those caused by rheumatoid arthritis, in which the joints shift and change the pressure area on the nerves. Comparatively, healing occurs faster than with freehand surgery.

What Is Nerve Entrapment?

Nerve entrapment, also known as nerve compression, is caused by trauma, injury, overuse, post-surgical complications, and typical surrounding structures. The symptoms of nerve entrapment can range from mild to severe pain, tingling sensations, or numbness, and, in extreme situations, there is rarely a chance of paralysis. Ultrasound-guided nerve hydro dissection is an extensively used technique to treat this condition.

What Is Ultrasound-Guided Nerve Hydrodissection?

Ultrasound-guided nerve hydro dissection is a minimally invasive technique used to identify the nerve entrapment and guide the needle to the nerve to treat a variety of pain and tingling sensations caused by nerve entrapments. It is especially beneficial for athletes to regain mobility and strength and experience pain relief. On the other hand, it is widely used as an alternative to open surgery or invasive procedures.

What Are the Conditions Treated With Ultrasound-Guided Nerve Hydrodissection?

Ultrasound-guided nerve hydro dissection is used to treat the following conditions:

• Carpal tunnel syndrome (CTS).

• Neurogenic thoracic outlet syndrome.

• Posterior interosseous neuropathy.

• Cubital tunnel syndrome.

• Piriformis syndrome.

• Morton's neuroma or interdigital neuroma.

• Scar neuropathy.

1. Carpal Tunnel Syndrome (CTS): Carpal tunnel syndrome is associated with compression of the median nerve, which travels the entire arm's length before passing through the carpal tunnel (placed near the wrist) and ending within the hand. Symptoms of numbness, tingling sensations, and hand fatigue are its peculiar features. Nerve compression is most commonly due to repetitive motion, hypothyroidism, obesity, rheumatoid arthritis, diabetes, and pregnancy.

2. Neurogenic Thoracic Outlet Syndrome: The thoracic outlet syndrome is associated with brachial plexus compression (which originates from the spinal cord and regulates sensation and muscle activity in the shoulder, arm, and hand), resulting in pain, numbness, and weakness of the arm and finger.

3. Posterior Interosseous Neuropathy: Posterior interosseous neuropathy occurs due to radial nerve (the nerve of the forearm that facilitates movement) entrapment. The most common symptoms are weakness in finger and thumb extension without sensory problems.

4. Cubital Tunnel Syndrome: The irritation of the ulnar nerve (the nerve that supplies the forearm) results in cubital tunnel syndrome, which causes discomfort and a disability to move the affected hand.

5. Piriformis Syndrome: This syndrome occurs when the piriformis muscle (located at the top of the hip joint or buttocks) compresses and irritates the sciatic nerve (the nerve supplies the hip muscles, lower leg, and feet). The pain or tingling sensation in the buttocks while sitting is aggravated by climbing stairs.

6. Morton's Neuroma: The compression of the digital nerve due to the thickening of the surrounding tissue results in Morton's syndrome, also known as an interdigital neuroma. The symptoms involve pain and discomfort in the forefoot, typically resulting in the sensation of walking on marbles.

7. Scar Neuropathy: Peripheral nerve injuries result in painful scar formation and occasionally complications.

What Are the Types of Ultrasound Injections?

There are two different types of ultrasound injections.

• In-plane injections

• Out-of-plane injections

1. In-Plane Injections: The most commonly used technique because of their capability to visualize the needle tip piercing the target. The method involves injecting the needle parallel to the transducer (a device that converts physical quantity into an electrical signal).

2. Out-Of-Plane Injections: With this approach, the needle tip enters the scanning sector of the probe as a hyperechoic or brilliant dot. This method is used in cases where the needle or probe cannot lie in-plane due to its complex anatomy.

What Are the Techniques of Ultrasound-Guided Nerve Hydrodissection?

The techniques differ from one person to another, and it is a repeated procedure in some patients based on the seriousness of the nerve entrapment. A strategic protocol is used to implement the technique.

1. The patient is advised to sit up straight, extending the forearm using a towel.

2. The Chlorhexidine two percent gel is applied from the forearm to the palm to attain an aseptic condition for the procedure.

3. A high-frequency ultrasound probe is placed proximally to the wrist and gently moved to identify the median nerve and the flexor retinaculum.

4. The needle is injected into the median nerve to deliver the injection (saline). When the nerve is inflamed, a corticoid with the anesthetic solution is injected. Simultaneously, ultrasound guides in the separation of the nerve and retinaculum.

5. If the nerve is still attached to the retinaculum, the previous step is repeated to promote the separation.

What Is the Outcome and Safety Regarding Ultrasound-Guided Nerve Hydrodissection?

The significant outcome of ultrasound-guided nerve hydro dissection is pain relief. The procedure is repeated after six months in the case of persistent pain. Unfortunately, after two rounds of injections, surgical intervention is required for chronic pain conditions due to nerve compression. Regarding safety, the study was conducted to evaluate the post-complications of ultrasound-guided nerve hydro dissection. As a result of investigations, the possibility of post-neurological complications (a nerve infection) with intraneural injection is rare but may include swelling at the injection site. Patients can return to their normal activities the day after the procedure.

Conclusion:

The hydro dissection technique is an upcoming technology that is promising in terms of safety and effectiveness. Although proving the efficacy of therapies that many believe improve patient care is critical, it is also tricky given how medicine is changing, particularly concerning payer systems and value-based care. The hydro dissection method is frequently employed in athletes to reduce the risk of nerve injury during the procedure and to relieve the pain.