What Are Common Cryosurgery Side Effects?

Cryotherapy is a medical device that uses physical methods to apply cryogenic substances and cryogenic equipment to destroy or remove human tissue at low temperatures, thereby achieving the purpose of treating diseases. It has the advantages of convenient operation, good treatment effect, high safety, no side effects, and short recovery time.

Chinese name: Cryotherapy
Foreign name: Cryotherapy Apparatus

Category Name: Cryosurgery equipment
Management category: Class III medical devices

Development History of Cryotherapy

In the middle of the 19th century, Arnott was the first to treat breast and cervical cancer with a saline solution containing crushed ice. This was the earliest attempt of freezing technology in the treatment of disease. With the establishment of gas liquefaction technology, cryogenic medical equipment is gradually applied, and the development of cryotherapy technology is inseparable from the progress of cryotherapy equipment. From the history of the development of cryotherapy equipment, it has been developing in the direction of pursuing less trauma, better performance, and more convenient use. The use of high power, fast cooling, no noise, small size, and low cost freezing methods will Will be the development trend of future cryotherapy apparatus. In 1961, Cooper and Lee jointly developed a temperature-adjustable liquid nitrogen cryotherapy device for the treatment of Parkinson's disease and other neurological diseases, which greatly promoted the development of cryotherapy, gradually gained clinical application, and became a modern cryotherapy Milestone. In the 1990s, the successful development of the multi-freeze probe system and the popularization of image monitoring brought the low-temperature medical technology into a brand-new era. In many cases, cryotherapy devices have become the best choice for minimally invasive interventional treatment of tumors. Cryotherapy in China began in the 1970s, and by the 1980s basic research and clinical applications were gradually deepening and were widely used in clinical practice ^[1] .

Basic structure of cryotherapy instrument

It usually consists of a low temperature device, a heating device, a storage container, a control system host and a probe. The probe acts directly on the body's treatment site. It is used to perform cryosurgery on local tissues using cryotherapy ^[2] .

How cryotherapy works

Cryobiological studies have shown that tissues rapidly cool to a low temperature of -40 ° C, and after three minutes, irreversible damage is caused. Cryotherapy is the use of refrigerant to produce low temperature action on the diseased tissue to make it necrotic in order to achieve the therapeutic purpose. The mechanism that causes the tissue necrosis is as follows ^[1] :

Freezing causes the formation of ice crystals inside and outside the cell, which is fatal to the cell. Under the effect of the ice crystal shear force, the cell membrane and cellular organs will be mechanically damaged and die.
The formation of ice crystals removes the water in the biological system, dehydrating the cells, and the electrolyte concentration in the aqueous solution of the cells is too high, which affects the activity of the enzyme itself, and even degenerates the enzyme, causing the cells to poison and die.
Low temperature denatures the major component lipoprotein complexes of cell membranes, leading to cell membrane rupture.
After rewarming, vascular microcirculation failure occurs in the tissue, and blood circulation is impaired, resulting in ischemia and cell death due to insufficient nutritional supply.
Low temperature immune effect. During the rewarming process, the damaged tissue protein has new antigenic properties, which stimulates the body's immune system and produces an autoimmune response.
Dephagy can occur during freezing injury. Dephagy cells originally exist on the periphery of frozen diseased tissue. During the process of phagocytosis, the cells fragment into membrane-encapsulated particles, which are then cleared by phagocytosis.

Cryotherapy instrument indication

The development of cryotherapy technology and cryotherapy equipment has been quite mature, and it is now widely used in clinical operations in dermatology, general surgery, urology, orthopedics, brain surgery, gynecology, ophthalmology, facial medicine, plastic surgery and other departments. In recent years, great progress has been made in tumor treatment. Tumor cryotherapy using liquid nitrogen is an effective method for clinically controlling tumor growth, especially an important method for treating large tumors with strong drug resistance. Cryotherapy technology is a hot spot in clinical treatment of tumors. It has been successfully used to treat prostate cancer, kidney cancer, etc., and can also be used to treat liver cancer and metastases, lung cancer, arrhythmia, etc., and has achieved rapid development in the treatment of bone tumors. ^[1] .

Cryotherapy instrument classification

Phase change endothermic cryotherapy instrument
Phase change refrigeration is the use of refrigerant state changes, that is, liquid gasification or melting and sublimation of solids to cool. Commonly used refrigerants are liquid nitrogen, liquid argon, liquid oxygen, nitrous oxide, and dry ice. Among them, the liquid nitrogen cryotherapy device is the most widely used and fastest developing cryotherapy device.
Gas throttling type cryotherapy instrument
Gas refrigeration uses the adiabatic expansion of high-pressure gas to obtain low temperature, and uses the expanded gas to reheat under low pressure to achieve the purpose of refrigeration. This type of cryotherapy device produces the Joule-Thomson effect (JT effect) during the gas throttling process. After the throttling, the gas pressure decreases and the temperature changes. Commonly used refrigerants include nitrogen, argon, nitrous oxide, and carbon dioxide. Common gas throttling cryotherapy apparatuses include argon-helium knives, liquid carbon dioxide chillers and nitrogen chillers. Low-temperature probes can be made into probes with different tube diameters as required.
Thermoelectric refrigeration cryotherapy instrument
Thermoelectric refrigeration uses the Peltier effect of semiconductors to achieve the purpose of cooling. That is, in a closed circuit composed of two different metals, the direct current is used to generate the principle that one contact becomes cold and the other becomes hot. Compared with phase change refrigeration and throttling refrigeration, thermoelectric cooling has the advantages of no pollution, no noise, no wear, and high reliability, but it has the disadvantages of insufficient temperature, large volume and low efficiency, which limits its clinical use.
Pulse tube cryotherapy instrument
The pulse tube cryotherapy instrument uses a pulse tube refrigerator as a cold source, which can reach a temperature below -80C. Select a suitable cryoprobe to gently press the affected part for treatment. The freezing depth and freezing area are easy to control and easy to operate. In the treatment of dermatological diseases, the pulse tube cryotherapy device can achieve a similar effect to the liquid nitrogen cryotherapy device ^[1] .

Cryotherapy device adverse events

pain
Pain is an adverse reaction that often occurs during cryotherapy, and almost all have different degrees of pain. In most cases, the pain can be tolerated, but there are also many patients who have severe pain and are difficult to tolerate. Sexual shock.
Blisters, blood blister
Local swelling, small blisters, or blood blister after thawing are common adverse reactions after freezing. Generally, no special treatment is needed, and it will gradually disappear after 1 to 3 days. Severe local swelling, blistering or blood blistering after freezing, and increased pain after pain reduction, should be paid attention to, most of which are large lesions on the head, face, hands and feet.
Secondary infection
Due to excessive cryotherapy or improper postoperative care, water / blood bubbles, blood scars, or punctures can cause exudation, erosion, infection, and even ulcers.
Pigmentation
Pigmentation is a common complication after freezing. The reasons for its formation are related to excessive freezing doses, early forced peeling of the skin, sunlight exposure, physical factors, and eating habits, such as flat warts, freckles, and pigmented spots that remain after freezing. Some pigmentation. For pigmentation after freezing, it usually fades or disappears after 3 to 6 months.
Hypopigmentation / loss
Locally caused hypopigmentation after cryotherapy is usually due to the deeper lesions. The use of a larger dose of cryotherapy results in a loss of pigment. Most of them can gradually return to normal within 3 to 6 months, but some always turn white and do not fade, and even the hair also turns white. Seriously affects aesthetics.
scar
Scar formation is often caused by larger and deeper lesions, larger freezing doses, postoperative infections, and other factors. Patients should be informed about the possibility of scarring (such as hemangiomas) before surgery, but the operation should be careful and careful. Preventing infection after surgery is to reduce or Effective measures to avoid scars.
other
Occasionally during the freezing process, adverse events such as urticaria, headache, fever, allergic reactions, heart-eye reactions, and cardiac blockage occur ^[1] .

Analysis of adverse events of cryotherapy apparatus

Medical device factors Any medical device product has a certain use risk, and the medical device approved for marketing is just a "risk-acceptable" product. Products are subject to technical level, cognitive level, and technological constraints in the process of research and development, design, manufacturing, and use. There are more or less inherent risks, as do cryotherapy devices. According to statistics, about 90% of patients will have various adverse events or complications of varying degrees during cryotherapy. Defects in the design of the cryotherapy device, production omissions, and inadequate technology will reduce the performance of the product, cause equipment failure, and shorten the service life, which is an important cause of adverse events.
Medical technology factors Cryotherapy is a relatively young and minimally invasive physical therapy method. Although great progress has been made, in the clinical application of cryotherapy apparatus, the freezing time, cooling temperature, freezing depth and range are largely determined by There is a lot of randomness in clinical experience. Medical staff must not only necrotic the diseased tissue as much as possible, but also damage the normal tissue as little as possible. Patients should not be eager to get the mentality and increase the intensity, frequency and time of freezing arbitrarily, so the professional level of the doctor is particularly important. Whether the pre- and post-operative care is proper, whether the equipment is sterilized strictly, and whether the operation is standardized will affect the surgical effect.
The patient's own factors. Individual patients have very different tolerances to freezing. A few sensitive or specific constitutional individuals respond differently to freezing. Elderly patients, those allergic to freezing and those who are weak need to be used with caution or without a cryotherapy device. People with cold urticaria, cold globulinemia, cold fibrinemia, cold agglutininemia, and Raynaud's disease are not suitable for cryotherapy. Some patients do not follow the doctor's advice and have a poor sense of self-protection. They often eat irritating foods or foods with excessive pigmentation after surgery, which leads to wound infection, pigmentation or scarring ^[1] .