Updated: Sep 9, 2021
Understanding Ultrasound-guided Hydrodissection Injections
Hydrodissection is accomplished by injecting fluids under hydrostatic pressure to free up one tissue from another (scar tissue, fascial adhesions). It is often specifically used to free up a peripheral nerve from adherent tissue that is compressing or impinging on that nerve. It can also be used to free up fascia around muscles or tendons from scar tissue, as is common in patients who have had prior surgery. We use ultrasound (US) guidance to ensure that the fluid is actually separating the adherent tissues from one another.
A definition found in the online dictionary states the following:
-Technique employing a pressurized fine stream of injected fluid to develop tissue planes or to divide certain soft tissues less traumatically than ordinary sharp dissection (with surgery).
This very detailed injection is often a good first choice to free up scar tissue, as surgical dissection often causes further scar tissue formation to form postoperatively, which can defeat the purpose of the surgery in the first place. It is particularly helpful after surgery in situations where scar tissue seems to be causing problems with persistent pain, usually related to nerves caught up in the scar tissue.
Common uses for Ultrasound-guided Hydrodissection injections in our practice include the following:
-Hydrodissection of adherent fascial or scar tissue after surgical procedures
-Hydrodissection of the sural or superficial fibular (peroneal) nerve and its dorsal cutaneous branches, to free the nerves from any adherent or impinging scar tissue about the ankle
-Hydrodissection of the median nerve at the wrist (carpal tunnel syndrome)
-Hydrodissection of the deep branch of the radial nerve at the radial tunnel of the elbow (radial tunnel)
-Hydrodissection of the ulnar nerve at the cubital tunnel of the elbow
-Hydrodissection of the median nerve at the elbow which causes lots of hand and wrist problems (pronator syndrome)
-Hydrodissection about the suprascapular nerve of the neck and/or shoulder
-Hydrodissection about the cervical or brachial plexus nerves causing radiating nerve pain like in thoracic outlet syndrome, or scapular winging
-Hydrodissection about the tibial nerve of the medial ankle (tarsal tunnel syndrome)
-Hydrodissection about the saphenous nerve about the knee, causing medial knee pain
-Brisement (freeing up of scarred down tendons) of the scar tissue around the peroneal or the medial ankle tendons after ankle trauma or surgery causing “stenosing tenosynovitis”
-Hydrodissection of the fibrotic, adherent fascial planes in frozen shoulder or post-surgery resulting in limited shoulder motion, especially between deltoid and the underlying rotator cuff tendons (supraspinatus, subscapularis, infraspinatus or biceps)
In conclusion, the advent of high-resolution ultrasound imaging has allowed us the ability to treat problems that were never treatable before, without open surgery. Unfortunately, with open surgery, oftentimes the trauma from the surgical procedure intending to free up scar tissue leads to creation of further scar tissue.
As such, the ability to offer ultrasound guided fluid-based injections to free up trapped nerves and fascial/scarred adhesions has proven to be revolutionary. In cases of more resistant or persistent scar tissue despite simple injections, additional substances such as hyaluronic acid gel or anti-fibrotic injectables from amniotic (placental) tissue can be used to further decrease the scar tissue and improve the ability of the fascial planes to glide on one another.
This is because hyaluronic acid is critical to the normal gliding of tissue fascial planes on one another. While our experience with these substances is still growing, and the science is lagging behind our experience, the revolutionary improvements we're seeing with patients are deeply encouraging.
For an excellent and more thorough review on the topic of Nerve Hydrodissection, I recommend reading Dr. Stanley Lam and Dean Reeves' most recent review on the topic here where you can also download the PDF version: https://doi.org/10.2147/JPR.S247208