Chronic Plantar Fasciitis: Is Cryosurgery The Answer?
Cryosurgery is the specialized field of using extremely low temperatures (controlled by a handheld probe) to destroy pathological tissue. This technique has been used for decades to treat malignant tumors of the prostate, liver and other organs.1-3 Cryosurgery is also gaining acceptance in dermatology, plastic surgery, urology and pain management.4-6 Now clinicians are using this technology to help manage common foot and ankle conditions.7-9
I have been performing cryosurgery for plantar fasciitis for approximately three years with excellent results. All of my patients who have had this procedure previously tried other treatments, including multiple steroid injections, NSAIDs, orthotics/arch supports and physical therapy, without success. Some have used night splints. Two patients had shockwave therapy, one underwent an endoscopic plantar fasciotomy and another had a percutaneous medial fascial release.
After undergoing cryosurgery, approximately 90 percent of the patients had complete resolution of pain or had only minor residual pain that required no treatment.
There have been very few complications with cryosurgery. Infection has been rare. The most common sequella has been the development of pain in another location of the heel or arch. This is the result of a postoperative compensatory gait and usually resolves in three to four weeks after the procedure. If patients receive this treatment, this compensatory fasciitis responds well to a course of NSAIDs, low dye taping or over-the-counter arch supports. Although the cryosurgery literature suggests that the analgesic relief with this procedure is temporary, a three-year follow-up has revealed virtually no recurrences of the plantar fasciitis.
Understanding The Scientific Principles Behind Cryosurgery
How does cryosurgery work? The basic principle of current cryosurgery systems is based on forcing gas under pressure of between 600 and 800 psig between the inner and outer tubes of the cryoprobe. The gas is released through a small opening into a chamber at the tip of the probe. As the pressurized gas is released into the chamber, it expands and results in a rapid drop in temperature. This is referred to as the Joule-Thompson effect and results in an ice ball forming at the uninsulated tip of the probe.10 The temperature can reach - 70ºC and the size of the ice ball can range from 3.5 mm to 10 mm depending on the amount of tube that is not insulated. Because these units are a closed system, no gas escapes from the cryoprobe.
In addition, the units can contain nerve stimulator capability and the cryosurgery systems by Cryotech (Cryomed Group Ltd.) have programmable freeze cycles and utilize multiple nitrous oxide tanks with automatic conversion from an empty to a full tank.
When one performs cryosurgery on peripheral nerves, the process is referred to as cryoneurolysis or cryogenic neuroablation. The nerve cells are destroyed as a result of the freezing process. The cold causes destruction of the axon with breakdown of the myelin sheath and Wallerian degeneration. This breakdown of the axon is more complete with repeated freezing of the nerve followed by periods of thawing. However, be aware that excessive freezing can lead to gross destruction of all tissues and prevent regeneration.4
Preserving the basic structural components of the peripheral nerve, the epineurium and perineurium, along with a very limited inflammatory reaction differentiate cryoneurolysis from other forms of neurolysis. An intact epineurium and perineurium permit ordered axonal regeneration and prevent the formation of amputation neuromas.