Cutaneous Cryosurgery ETHAN E. ZIMMERMAN, MD, and PAUL CRAWFORD, MD Nellis Family Medicine Residency, Nellis Air Force Base, Nevada Cutaneous cryosurgery refers to localized application of freezing temperatures to achieve destruction of skin lesions. It can be used to treat a broad range of benign and premalignant skin conditions, and certain malignant skin condi- tions, with high cure rates. Cellular destruction is accomplished by delivery of the cryogen via dipstick, probe, or spray techniques. It is widely used in primary care because of its safety, effectiveness, low cost, ease of use, good cosmetic results, and lack of need for anesthesia. Cryosurgery is as effective as alternative therapies for most cases of molluscum contagiosum, dermatofibromas, keloids, and plantar or genital warts. It is a more effective cure for common warts than salicylic acid or observation. Cryosurgery is generally the treatment of choice for actinic keratosis. Contraindications to cryosurgery include cryofibrinogenemia, cryoglobulinemia, Raynaud disease, agammaglobulinemia, and multiple myeloma. Complications from cryosurgery include hypopigmentation and alopecia, and can be avoided by limiting freeze times to less than 30 seconds. Referral to a dermatologist should be considered in cases of diagnostic uncertainty or for treatment of skin cancer, which requires larger amounts of tissue destruction, resulting in higher complication rates. (Am Fam Physician. 2012;86(12):1118-1124. Copyright © 2012 American Academy of Family Physicians.) ryosurgery refers to localized Destruction of malignant cells requires a application of freezing tempera- final tissue temperature of –60°C (–76°F).1 tures to achieve destruction of To treat malignant lesions other than mela- body tissue. It is used primarily noma, clinicians should use intermittent C for cutaneous lesions, but also has wider spraying to allow deep penetration of the ice applications in ophthalmology, gynecology, ball, which can result in a maximum depth neurosurgery, cardiology, and oncology.1-3 of 10 mm. An ice ball is the total volume of Cryosurgery has been used for more than tissue destroyed by freezing; if viewed in 150 years to treat a broad range of benign and cross-section, it would appear as a sphere. premalignant skin conditions, and certain The same amount of tissue destruction malignant conditions, with high cure rates.1 should occur as would be removed during Liquid nitrogen—the modern cryogen of an excision, which may require debulk- choice—became commercially available in ing before freezing. The total thaw time the 1940s. Since that time, cryosurgery has between freezes for a malignant lesion been commonly performed in the outpatient should be at least 90 seconds after reach- setting because of its safety, effectiveness, ing adequate temperature at the base of the low cost, ease of use, good cosmetic results, ice ball, because slow thawing increases the and lack of need for anesthesia.1,4 concentrations of toxic levels of electrolytes in the surrounding tissues.1 Shorter thaw Mechanism and Goals times are associated with incomplete eradi- Cryosurgery can be accomplished through cation of malignant cells. an open spray technique, or through direct Conversely, when treating a superficial application of a dipstick or cooled probe. lesion, a continuous spray technique will Liquid nitrogen has a boiling point of limit the depth of freezing due to deflection –195.6°C (–320.1°F). When tissue is cooled, of the gases. Treatment of benign lesions is it is injured by ice crystal formation within simpler because the rapid freezing causes cells, vascular thrombosis and stasis, and the sloughing of the epidermis from the dermis. release of electrolytes and toxins. An open spray transfers heat (causes cooling of the Equipment and Design skin) faster and is more damaging to tissues, DIPSTICK but firm pressure and use of lubricating jelly Application of liquid nitrogen with a cotton- can speed freezing time when using a probe.1 tipped applicator is sufficient for treating Downloaded from the American Family Physician Web site at www.aafp.org/afp. Copyright © 2012 American Academy of Family Physicians. For the private, noncommer- 1118 Americancial use of one Family individual Physician user of the Web site. All other rights reserved.www.aafp.org/afp Contact [email protected] for copyrightVolume questions 86, Number and/or permission 12 ◆ December requests. 15, 2012 Cutaneous Cryosurgery SORT: KEY RECOMMENDATIONS FOR PRACTICE Evidence Clinical recommendation rating References Malignant skin lesions should not be treated using the dipstick method C 1 because of inadequate depth of freezing. Cryosurgery is more effective than salicylic acid or observation for the B 16, 17 cure of common warts, but not plantar warts. Cryosurgery is highly effective for actinic keratosis and is the treatment of C 5 choice for most patients. A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evi- dence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to http://www.aafp.org/afpsort.xml. benign, superficial lesions (Figure 1). It does nitrogen can be directed at any skin lesion, not freeze to an adequate depth to eradicate whether benign or malignant. Superficial malignancy.1 and irregular lesions are amenable to this therapy as well. Different techniques (e.g., OPEN SPRAY pulse, continuous, spiral, paint brush) can Using one of several commercially available be used to adequately freeze1 (Figure 3). The spray guns (Figure 2), a fine spray of liquid spray is directed from a 90-degree angle at a distance of 1 to 2 cm. A video of the open spray technique is available at http://www. youtube.com/watch?v=CQxQ3ucfis4. CONFINED SPRAY Confined spray is used particularly when sensitive structures are nearby. A cone directs the cryogen to the skin (Figure 4).1 Clinicians can use the standard, common spray gun with an ear speculum, or a com- ILLUSTRATION BY DAVID KLEMM Figure 1. Cryosurgery devices include a cotton- mercial product (CryoPen) using small tipped applicator (left), liquid nitrogen spray canisters of nitrous oxide, which has a (center), and a cryoprobe (right). temperature of –127°C (–196.6°F). A video A B Figure 2. Examples of liquid nitrogen equipment include (A) a Cryogun spray canister and (B) assorted nozzles of vary- ing aperture size and length. December 15, 2012 ◆ Volume 86, Number 12 www.aafp.org/afp American Family Physician 1119 Cutaneous Cryosurgery demonstrating the combined spray with a CryoPen is available at http://www.youtube. com/watch?v=7aV_qcgAwKE. CRYOPROBE Application of a precooled metal instrument, or cryoprobe, against the lesion is useful for 1 Lesion Ice field round lesions on flat surfaces. Clinical Applications Because there are often multiple possible Direct spray Paintbrush Rotary or spiral spray ILLUSTRATION BY DAVID KLEMM treatment modalities for cutaneous lesions, Figure 3. Liquid nitrogen spray patterns. clinicians should consider factors unique to the patient when selecting treatment. For example, a patient who is averse to pain or who has large areas of affected skin might be better suited to a topical remedy than to cryosurgery.5 However, several factors may make cryotherapy a better option than sur- Cone shield (shown in cross section) gical intervention: a history of poor wound healing, intolerance to local anesthesia injec- tion, anticoagulant use, indwelling pace- makers, or the presence of several scattered lesions.2 Some general advantages of cryo- 1 to 1.5 cm surgery are listed in Table 1.1,6 Contraindications to cryosurgery are fairly rare, but there are situations in which Lesion 2,7,8 ILLUSTRATION DAVID BY KLEMM it should be used with caution (Table 2). Figure 4. Confined spray technique using an It should not be offered to patients with open cone shield to direct the liquid nitrogen a proven sensitivity to the cryogen. Nei- to the lesion. The spray nozzle is positioned ther should it be used on a skin lesion for approximately 1 to 1.5 cm above the lesion. which the diagnosis is uncertain.7 Cryosur- gery should not be attempted on children younger than seven years because of the pain 9 Table 1. Advantages of Cryosurgery associated with the procedure. Some older vs. Conventional Surgical Techniques children also may be reluctant to undergo cryosurgery for the same reason. However, Anesthesia optional topical application of lidocaine tape or Excellent cosmetic results lidocaine/prilocaine cream (Emla) before Low cost or immediately after freezing may help chil- 10,11 Low risk of infection dren tolerate the procedure better. Minimal wound care BENIGN LESIONS No need for suture removal No work or sport restrictions Cryosurgery for genital warts and common 11-13 Portable to multiple treatment settings warts has a cure rate of 60 to 86 percent. Safe procedure Several treatment sessions with long freeze Short preparation time times may be necessary depending on the Useful in pregnancy size and location of the warts, with plantar warts requiring the longest course of treat- Information from references 1 and 6. ment (Table 31,2,7,9,14). Topical keratolytics and simple occlusive therapy also have reasonable 1120 American Family Physician www.aafp.org/afp Volume 86, Number 12 ◆ December 15, 2012 Cutaneous Cryosurgery Table 2. Contraindications and Cautions to Cryosurgery Relative contraindications Perform with caution Agammaglobulinemia