The benefits of hydrodissection are becoming more widely known but because many people have not been exposed to it I wanted to give a more in depth description and provide examples of how it can be used.
Doctors have been using nerve blocks for as long as we have had local anesthesia. It is something that is done every day in ERs, pre-op areas, and clinics all over the world. The most precise way of doing a nerve block is often to use an ultrasound machine to guide the injection. The goal is usually to surround the target nerve with medication in order to temporarily interrupt the function of the nerve. We know that there is really no extra space inside the body so when the medication is injected, the surrounding structures are displaced away from the nerve by the fluid.
Hydrodissection uses this exact technique, but instead of the goal being to interrupt the function of the nerve, the goal is to capitalize on the fact that we are displacing tissue off of the nerve and use this action to disrupt adhesions that have formed between the nerve and the surrounding structures. The other difference between this and a normal nerve block is that the fluid that is used contains very little if any local anesthetic. All that is really needed is something to physically separate structures from each other. Commonly used solutions are primarily made of a weak dextrose solution mixed with vitamin B12 and/or a small amount of lidocaine. This same approach can be used to help release muscles which have become adhered to their investing fascia, or scar tissue which has formed over surgical hardware that is restricting normal movement somehow.
A common instance where this is used is in treating piriformis syndrome. As the sciatic nerve exits the greater sciatic foramen it often passes deep to the piriformis and superficial to the superior gemellus. Not only can the muscles in this area become hypertonic, existing in a continual partially contracted state, but the nerve can become adherent to the fascia around it as well. In the worst cases the condition involves all of the external hip rotators down to the level of the quadratus femoris. As you might imagine this makes it impossible for the nerve to slide back and forth with hip flexion or to move side to side when the patient sits on a hard chair. We all know nerves do not like to be stretched or pinched and in these cases the nerve is having both done to it any time a person walks or sits.
To treat this condition, areas where the nerve is impinged are identified using ultrasound assisted physical exams. Once we have identified the problem area(s) the ultrasound is used to guide a precise injection of fluid to address the structures involved. In this example, the fluid is directed all the way around the sciatic nerve at the level where the impingement is occurring. It is quite common to have to treat the deep and superficial aspect of the piriformis as well as the superior gluteal nerve at the same time since part of the problem is that the muscle cannot relax in a normal way.
In many cases, the patients will feel an immediate improvement in their symptoms as the injections are being done. Most patients will give feedback during the procedure indicating that “that’s the exact spot where I feel my pain” or something similar. It is common for people to describe the feeling of an itch that they have been trying to scratch for years finally getting scratched. Once the injections are in, we will sometimes have the patient run the joint through range of motion. This helps the fluid spread even further along the structures or facial planes in order to break up any additional adhesions we were not able to address with the injection. Alternatively, if the nerve that is being treated is quite superficial as is the case with the fibular nerve at the fibular head or the ulnar nerve at the elbow, the area is massaged in order to accomplish the same thing. The ultrasound can then be used to evaluate for adequate spread of the fluid and restoration of normal morphology and/or movement of the nerve.
While hydrodissection alone can improve symptoms significantly, many patients benefit from working with a professional after the procedure to springboard off of the mobility gains, and return of muscle recruitment that they experience with hydrodissection. Myofascial release, nerve flossing, and neuromuscular re-education techniques are just a few of the modalities that commonly work well in concert with hydrodissection.
It is also common for there to be benefit in alternating these techniques with additional hydrodissection treatments. A good example of this is when treating “frozen shoulder” While adhesive capsulitis is sometimes the core of the problem, oftentimes the capsule is fine, but the surrounding muscles are stiff, unable to be recruited and generally dysfunctional. These are some of my favorite cases to take on with a team approach. I’ll ask the patient to move the shoulder and to tell me where the most restriction seems to be coming from. I will then target injections to either the muscles in that area or nerves leading to those muscles. This often results in an immediate improvement, but then reveals the next restriction that is most limiting. Over the course of an hour appointment, we work our way through the different restrictions as they are uncovered by each subsequent injection sort of like peeling the layers off of an onion. When the patient can no longer identify a point of maximum restriction, I send the patient back to see their physical therapist or chiropractor for further treatment with instructions to return to see me if they hit another plateau with their progress. It is quite common for the patient to be clear of symptoms with full range of motion in a very short time with this approach.
There are as many different applications for this technique as there are nerves in the body. Cervicogenic headaches can be improved with treatment of the occipital and sub occipital nerves as well as the high cervical nerve roots. Neck and shoulder pain can be improved with treatment of the cervical nerve roots and their branches. Low back and gluteal pain can be helped with treatment of the lumbar nerve roots, muscles of the low back, cluneal nerves, subcostal nerves and others.
As a provider who treats pain, I am always trying to identify and treat the pain generator. What is it that is actually causing the pain? In so many cases I have found that the nerves are often either the source or a large contributor to a patient’s pain. This technique allows us to address this problem in a safe, very precise, long lasting way which results in significant improvement in outcomes and patient quality of life.