Cryosurgery: Cryoablation for Neuroma Pain
Benefits of Cryosurgery:
- Long term pain relief
- Low incidence of complications
- High procedure success rate
- Office based procedure
- Treatment may be repeated
- Immediate ambulatory status
- Short patient recovery time
- No stump neuroma formation
Principles of Cryosurgery
Cryosurgery is the specialized field of using extremely low temperatures to destroy pathological tissue. The technique has been used for decades to treat tumors throughout the body. It is used in several medical fields and has become an important modality to reduce foot pain associated with Morton’s Neuroma. The basic principle of cryosurgery systems is based on forcing a gas under pressure 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. The temperature can reach -70 C and an ice ball forms. 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. Axons regenerate at the rate of 1 to 3 mm per day, the analgesic or anesthetic effect of cyroneurolysis can be considered temporary. Cellular necrosis following cryoneurolysis results in a release of tissue proteins and this facilitates a change in protein antigenic properties. This could result in an autoimmune response specific to the cryolesion. This autoimmune response might explain the prolonged analgesic relief that lasts longer than the time required for regeneration of the axon.
A Neuroma is a progressive, degenerative enlargement of a nerve that is often associated with severe lancinating pain, numbness, cramping and eventual loss of function. Morton’s Neuroma forms between the 2nd and 3rd, or 3rd and 4th metatarsal and digital areas. The nerve and surrounding tissue becomes irritated, inflamed and often enlarged leading to symptoms. Constricting shoes combined with excessive stress to the forefoot are often blamed as the cause of the pathology, but as in most medical conditions there is a strong genetic factor as well as a lifestyle factor. Those who run, walk on treadmills, dance, engage in various sports which require pressure under the metatarsal area and people who wear tight dress shoes seem to be more prone to this condition.
- Morton’s Neuroma is noted more often in women than men
- There are no outward signs of the condition, occasionally some edema is noted under the ball of the foot
- Burning pain in the ball of the foot that radiates into the 2nd, 3rd or 4th digits, most often occurring when active and in a closed shoe. Night pain is rare.
- Pain occurs when barefooted on very hard or uneven surfaces, but rarely occurs when barefooted on a thick carpeted area.
- Pain intensifies with activity.
- Numbness may occur in the toes
- Runners may feel pain as they push off from the starting block.
- High-heeled shoes can aggravate the condition by placing weight on the ball of the foot.
Although Morton’s Neuroma is a very common problem associated with forefoot pain, it is not the only pathology possible in a diagnosis. To properly determine the cause of the complaint several tests are needed. Besides palpation of the area to check for certain pathology which may be present, radiographs are needed to rule out bone tumors, stress fractures, arthritic spurs and a multitude of osseous possibilities. It is also highly recommended that Ultrasound study be performed to determine the extent and location of the nerve enlargement, the amount of inflammation and more importantly to help definitively rule out other pathology such as foreign bodies, ganglions and bursitis.
For many years functional orthotics, cortisone injections, alcohol sclerosing injections and surgical excision were the only option. Functional orthotics is still highly recommended, especially for those who live an active lifestyle, but they tend to limit types of shoes available for the patient. Cortisone injections offer some immediate relief but often are painful and temporary. Alcohol sclerosing requires multiple injections, often 6-8 shots to reduce or eradicate the pain. Neuroma surgery has a variety of risks including the possibility of a formation of a “Stump Neuroma” which will require additional invasive surgery years later. Neurectomies have inherent risks that are associated with all invasive surgeries as well as requiring bandaging and limited activity over a 2-3 weeks timeframe.
Cryosurgery at our office:
Dr. Randell Braun introduced cryosurgery in 2005 as an alternative to invasive surgery. Needless to say, at this time she has performed hundreds of these procedures reducing the need for invasive surgery by over 95%. The vast majority of patients experience significant if not complete relief of symptoms after one session; a small percentage of patients require a second session of cryoablation. For the rare patient that does not see a sufficient amount of pain reduction or complete resolution of symptoms, Dr. Braun will perform a surgical neurectomy.
On the day of the procedure, an ultrasound is used to determine positioning of the probe. The area is anesthetized with a local injection and a very small incision is effected over the painful area. The probe is introduced and freezing is initiated for a period of 2-3 minutes. The area is allowed to thaw and with the use of the ultrasound the probe is repositioned. The procedure is repeated from 2 to 4 times depending on each individual case. Cortisone is often injected after the procedure while the area is numb to work in conjunction with the ablation. The site is covered with compression bandage and patient is advised to reduce activity, ice and elevate for the remainder of the day. Bandage can be removed the following day and patient can cover area with Band-Aid. Normal activity can be resumed within one or two days of the procedure and any pain that occurs is managed with an OTC anti-inflammatory or Tylenol. Pain continues to reduce over a two week period; if at the end of the two week period the reduction is not sufficient the procedure can be repeated.
Dr. Braun is one of only a handful of podiatrists performing this procedure in this country and is presently the only doctor in the Deep South offering cryosurgery for neuroma or fibroma pain. She initiated this modality when podiatric cryosurgery became available and has performed multiple cases per week since. For available appointments please call her office at 251-626-5065.