CRYOSURGERY Pattippa Sumalai, M.D. Jutamas Tankunakorn, M.D. 23/09/2014 Use of extreme cold to destroy cells of abnormal or diseased tissue Recommended for patients considered to be poor surgical candidates Objective : to cause necrosis of tissue Fitz patrics dermatology edition 8 th p.2968 Tissue destruction from cryotherapy results from - Direct cell injury - Vascular stasis - The local inflammatory response Freezing cells convert water to ice (crystallization) - Rapid freezing causes intracellular ice crystal formation - Slow freezing cause extracellular ice formation (less cell damage) During thawing, recrystallization occurs when ice crystals fuse to form large crystals that disrupt cell membranes As the ice melts further, the extracellular environment becomes hypotonic, causing water to infuse into cells and cause cell lysis Fast freeze and slow thaw After freezing stasis within the vasculature occurs Loss of circulation ->anoxia is a major mechanism of injury from cryosurgery As the tissue thaws over 0 o C ( 32 o F ) - Brief hyperemic response ensues, with resultant edema and inflammation Fitz patrics dermatology edition 8 th p.2969 Benign lesions : -20 to 30 o C Malignant tissue : -50 to 60 o C Bolognia edition 3 rd p.2284 LesionFreeze times ( seconds ) Verruca plana5 Solar lentigo3-5 Actinic keratosis8-10 Seborrheic keratosis10-15 Sebaceous hyperplasia5-10 Verruca vulgaris15-20 Keloid30 LesionFreeze times ( seconds ) Dermatofibroma60 Acne cysts5-15 Myxoid cysts15-20 Actinic cheilitis10-20 Bowens disease20 Lateral spread of freezes - Wart 2-3 mm - BCC at least 3-5 mm or more Freeze-thaw cycle - Single cycle benign and premalignant conditions - Double cycle malignant lesions Bolognia edition 3 rd p.2284 Bolognia edition 3 rd p.2285 Viral contamination of liquid nitrogen may occur when treating warts or other infectious lesions if a dipstick method is used The most frequently used technique Solid central : used on lesions smaller than 0.5cm Circular intermittent pattern : 1-2 cm lesions Paintbrush pattern : greater than 2 cm Contact therapy Consist of a flat, precooled metal tip placed firmly onto lesion Round lesions, flat surfaces Indication - Patient taking coagulations - Previous history of poor wound healing after standard surgical procedures - Fair skin - Multiple large lesions - Wart and molluscum contagiosum in HIV infected patients - Very extensive, recalcitrant to therapy - Patients with adverse reaction to anesthesia Lesions overlying nerves (postauricular nerve on the neck, digital nerves on medial and lateral fingers and toes) Sites prone to scarring with retraction (eyelids, mucosa, nasal ala, auditory canal) Patient with darkly pigmented skin (hypopigmentation) Bolognia edition 3 rd p.2284 Absolute contraindications - Lesions that require histopathology for diagnosis - Recurrent non-melanoma skin cancers Relative contraindications - Cold urticaria - Abnormal cold intolerance - Cryoglobulinemia or cryofibrogenemia - Tumors with indistinct borders or darkly pigmented features Indications - Type of skin cancer : superficial BCC, nodular or ulcerated BCC, small well-diff. SCC arising in Aks Selection of tumors - Tumors under 2 cm in diameter - Tumors with definable margins - Infected tumors Bolognia edition 3 rd p.2284 Tumor over 2 cm in diameter Recurrent tumors (exception of postradiotherapy) Tumor with a high-recurrence rate Tumor on the feet and lower legs, where the time of healing can be protracted up to several months Tumor with the histological diagnosis of morpheaform or sclerotic, metatypical, or mixed type Single cycle of freezing is sufficient for most superficial tumors Double cycle of freezing is used for tumors that are 3 mm or more in depth An edematous, weeping reaction develops, follow by eschar formation About 1 month heal by second intention, leaving a hypopigmented soft scar 5-15 minutes after freezing : erythema, edema Several hours : vesicle, bullae After drying of the bullae : eschar form Simple cleansing with soap and water Benign and premalignant lesions heal in 1-2 weeks, malignant lesion requiring 3-4 weeks Healing may be slower on the helix of the ear, scalp, dorsum of the hand and the lower leg Final apperance : soft hypopigmented macular with slight textural change Incidence : low May arise in several ways - Unexpected event e.g. infection - Unsatisfactory cosmetic result e.g. hypertrophic scarring - More pronounced response of the tissue to freezing than that been anticipated e.g. residual hypopigmentation Generally resolve spontaneously - Edema - Hypertrophic scar ( resolve within monts ) - Uncommon reactions : delayed bleeding, headache, paresthesias, neuropathy, secondary infection, syncope, nitrogen gas insufflation, milia, hyperpigmentation Retraction of tissue (e.g. lip, eye brows, ala nasi), tissue defect, depigmentation, notching, ectropion, alopecia, and contour defects