cryo madhuryA77.docx

**CRYOTHERAPY** MODERATOR : DR. HARIKISHAN KUMAR. Y PRESENTER : DR. MADHURYA. S Cryosurgery is that branch of therapeutics that makes use of local freezing for the controlled destruction or removal of living tissues. It is safe , inexpensive, reproducible, repeatable and simple office procedure....

**CRYOTHERAPY** MODERATOR : DR. HARIKISHAN KUMAR. Y PRESENTER : DR. MADHURYA. S Cryosurgery is that branch of therapeutics that makes use of local freezing for the controlled destruction or removal of living tissues. It is safe , inexpensive, reproducible, repeatable and simple office procedure. Provides high healing rates even in difficult areas with excellent cosmetic results. A cryogen is a substance used for cryosurgery. Over the years several cryogens have been used **.** Liquid nitrogen is the coldest refrigerant available and is the cryogen of choice for dermatological cryosurgery and the only cryogen advocated for malignant skin lesions. Freezing points : (in ° C) Liquid nitrogen -196 Liquid oxygen -183 Nitrous oxide -89 Solidified CO2 -78 Dimethyl ether -24 Various mechanisms are responsible for cellular and tissue injury. These include the following: **DIRECT TISSUE INJURY :** Heat transfer, cell injury, inflammation. **INDIRECT TISSUE INJURY :** Vascular stasis , tissue hypoxia. **IMMUNOMODULATION:** Exposure of viral particles to immune system. ***Ice formation/ cell injury**: On spraying the cryogen , there is rapid transfer of heat from the tissue to the cryogen with ice formation in the extracellular compartment. The extracellular solutes are concentrated , setting up an osmotic gradient with movement of fluid extracellularly and concentration of solutes intracellularly leading to cell damage.* Extracellular ice formation damages the cell membranes, while intracellular ice is thought to damage the mitochondria and endoplasmic reticulum. ***Osmolarity changes:***Extracellular ice formation is associated with a decrease in extracellular water and a resulting increase in the solute concentrations. This brings about cell membrane disruption. ***Thermal shock**. And denaturation of lipoprotein complexes. Rapid freezing and slow thawing maximize epithelial tissue destruction and are therefore preferred in treating malignant skin cancers (-50 C )* ***Vascular changes:*** There is ischemic necrosis that starts around the vessels as a result of microthrombi within the capillaries and arterioles producing tissue destruction. ***Cryoimmunomodulation**:* There is some evidence that low temperatures can induce effective immune recognition of the remaining viral or tumor cells. The above mechanisms are further dependent on several factors such as rate of freezing, rate of thawing (rewarming), temperature achieved, type of tissue and its vascularity, and soon. Rapid freezing (more intracellular ice formation) and slow thawing (rupture of cells) is more destructive than slow freezing and rapid thawing. **INDICATIONS :** **VIRAL :** warts, molluscum contagiosum, condyloma acuminata. **BENIGN** : cystic acne, acne scars, keloid, granuloma pyogenicum, skintags, seborrheickeratosis,mucoid cyst, xanthalesma , DPN, syringomas, milia. **PREMALIGNANT LESIONS** : leukoplakia, Bowen's disease, erythroplasia of Queyrat, and actinic keratoses. **MALIGNANT LESIONS** : basal cell carcinoma, basal cell nevus syndrome, squamous cell carcinoma, lentigomaligna, and lentigomaligna melanoma can be treated by cryosurgery. The tumors less suitable for cryosurgery are those that are large (over 2 cm in diameter), recurrent, or on the feet or lower legs. **CONTRAINDICATION:** Absolute Contraindications to cryosurgery are Blood dyscrasias Agammaglobulinemia, coldintolerance and cold urticaria, lesions for which tissue pathology is required. Lesion in an area with compromised circulation. Proven sensitivity or adverse reaction to cryotherapy RELATIVE CONTRAINDICATION : Keloidal tendency cryoglobulinemia, cryofibrinogenemia Raynaud's disease, pyoderma gangrenosum, collagen vascular and autoimmune diseases multiple myeloma sensory loss at lesional site concurrent treatment with immunosuppressives patients on renal dialysis. **Preprocedure Steps** - The preprocedure steps are as follows: - Pre treatment photographs, if necessary. - A biopsy to confirm the diagnosis in case of malignant and premalignant conditions - Explanation of the procedure to the patient and obtaininga written informed consent; and - Analgesics may be given 1--2 hours before the procedure. - Area to be treated should be cleaned with povidone iodine or surgical spirit. - Topical or local anaesthesia may be used in thick lesions requiring longer freeze-thaw cycles. **Procedure** The following five methods of application have been described: ***Dipstick technique:***A cotton tipped applicator is dipped in liquid nitrogen and applied firmly to the lesions until a arrow halo of white ice forms around the bud. This is the simplest method. Efficacy is less than the other techniques. Requires more freeze thaw cycles. ***Spray technique:***This is the most popular method. The spray method employed may be spot freeze, paint brush spray method, spiral spray method, or rotatory spray method. Liquid nitrogen is poured from the storage container into the spray unit slowly using a funnel, until the unit is filled up to 2 inches from the brim. After the lid is screwed back, one should wait for 3--4 min for the pressure to build up. The appropriate screw-on brass spray tip is selected (i.e. the one that sprays within the borders of the lesion). For a single short freeze, no local anesthesia is required, but if the lesion is large it requires more freeze time, then local anesthesia (1% lignocaine) should be given. The periphery of the lesion is marked and a rim of normal tissue (benign, 1--2 mm; premalignant, 3--5 mm; malignant,5--10 mm) is included. The spray tip is held 1 cm away and a steady spray ofliquid nitrogen is directed at the center of the marked lesion. The ice field gradually extends up to the edge of the circle.The freeze time commences once solid ice has formed overthe entire marked area. The spray is adjusted to maintainan ice ball of constant size and for the required period (from5 sec to 30 sec; normally not more than 30 sec). The lesion is allowed to thaw slowly. It should be allowed to thawcompletely before refreezing if a second freeze is required. The skin should be palpated to check for the resolution of the firmness (ice) from the tissue. **Timed spot freeze technique** : cryogen is sprayed directly on the lesion through an appropriate sized nozzle , which is chosen according to size of lesion. For adequate treatment , the lateral spread of freeze should extend atleast 2mm beyond the margin in benign and 5 mm or more for malignant lesion. This spot freeze can be carried out in 2 ways : 1. Paint brush method : lesion is treated by spraying from one side of the lesion and moving up and down across the lesion. 2. Spriral method : the cryogen is sprayed initially in the center of the lesion and then moved outwards in concentric circles. ***Cryoprobe technique:***Here, liquid nitrogen is circulated so as to cool the tip of the cryoprobe to be applied to the lesions. Cryoprobes vary in size from 1 cm to several cm in diameter. A probe suitable to the lesion to be treated is selected and is precooled before application to the surface of the lesion. Its tip is applied firmly to the lesion and cooling is commenced. The probe is allowed to thaw sufficiently before removing it from the treatment site. A repeat cycle, if required, should be commenced after allowing the lesion to thaw completely. ***Cryoroller technique:*** This is similar to the dipstick method. The metallic (stainless steel or brass) cylindrical end (of various sizes) of the roller is dipped in liquid nitrogen held in a polystyrene, thermocol, or plastic cup and then rapidly rolled over the acetonized surface of the lesion. Indications include nodulocystic acne, hypertrophic scars, and keloids. It spares or minimizes surface necrosis, ulceration and pigmentary changes while attaining good results. ***Cone spray technique:***This is used to concentrate the spray and limit its lateral spread. A cone of sufficient skin surface size is chosen to encompass the field to be frozen. There is a very rapid rate of fall in temperature and therefore this method is more destructive than the open spray method. **Intralesional cryotherapy** : This method is suitable for hypertrophic scars and keloids with a depth of \> 2 cm and is hence proving to be better than spray and cryoprobe techniques for these lesions. A wide bore needle is inserted into the keloid parallel to the skin surface, and the nozzle of the cryogen is connected to this needle, for delivering liquid nitrogen , the needle is withdrawn after thawing. The epithelial layer is not destroyed in this technique and hence the residual hypopigmentation is avoided. **Forceps / clamp technique** : This method is useful for quick and relatively painless removal of small skin tags. It involves dipping a needle holder or a hemostat in liquid nitrogen for about 15 secs and holding the stalk of a pedunculated skin tag for 10 secs. The frozen skin tag falls off in 7 to 10 days. **Thermocouple devices** : to effectively monitor optimum temperatures achieved at cryotherapy sessions , a temperature probe coupled to a digital thermometer that can read upto -75 c can be used. Freeze time : *Benign skin conditions:* Common warts 10--15 sec plane or filiform warts 5 sec molluscum contagiosum 5--10 sec seborrheic keratoses 10--15 sec acne cysts or scars 5--10sec skin tags 5--10 sec keloids 20--30 sec prurigo nodularis 20--30 sec Pre-malignant Solar keratoses 5--15 sec Bowen's disease 20--30 sec Leukoplakia 25--30 sec For adequate depth of cryonecrosis of most tumors, one should perform at least two 30 sec freeze--thaw cycles with an intervening 5 min thaw period. **POST PROCEDURE:** During and immediately after a 30--40 seconds freeze, the skinshows a white ice field. Within a few minutes, a violet color appears at the periphery and moves centrally both on the skin and deeper. It is clearly demarcated from the surrounding healthy skin. Before long, the deeper tissues become paler, while a hemorrhagic blister forms on the surface. This turns into an eschar, which lasts for a few days or weeks. The frozen area contracts after 10--14 day. 1. Analgesics may be prescribed to alleviate pain if present. 2. Topical antibiotics can also be given to prevent secondary infections. 3. If the blister is large , it maybe punctured with a sterile needle and the roof left in position to act as a natural barrier. 4. The patient is asked to visit the dermatologist for a follow-upsession after 10--15 days to assess the lesion or even earlier if a large blister or secondary infection (severe pain, swelling, or redness) develops. The procedure can be repeated after three weeks if required. COMPLICATIONS : IMMEDIATE COMPLICATION : - Edema and blister formation - Pain during and immediately after the procedure. - Headache on freezing lesions on head and neck areas. - Vasovagal attack in overly anxious patients. - Rarely, bleeding can occur at treatment site. DELAYED COMPLICATIONS : - Hemorrhagic necrotic blister formation. - Wound infection. - Delayed wound healing. - Rarely , scar hypertrophy. PROTRACTED COMPLICATIONS : - Hypopigmentation at the site of treatment due to destruction of melanocytes. - Atrophy. - Cicatricial alopecia. - Milia formation. - Hypoesthesia. ADVANTAGES AND DISADVANTAGES OF CRYOTHERAPY : ADVANTAGES : - Outpatient procedure - Minimal or no post procedure recovery time. - No need of anaesthesia most of the times. - Less expensive , affordable. - Less time consuming. - Minimal complications. DISADVANTAGES Pain is a common complaint. - Multiple sessions maybe required - Post treatment edema and blister formation. - In dark -- skinned individuals , hypopigmentaion following treatment may be is a cause of concern. 1. Bangera. A , Satish DA. Cryotherapy. In. IADVL Textbook of dermatology volume 3.