Cryosurgery Flashcards
What are the cryogenic agents?
Liquid nitrogen, NO, CO2
What temperature does benign tissue destruction occur at? Malignant tissue?
- Tissue destruction occurs between -10 and -20C
2. Malignant cells are completely destroyed between -40 and -50 C
What are the portable canisters used for?
Portable canisters are only for benign lesions (propane, dimethyl ether)
What is the physiology of cryosurgery?
Freezing of epidermis results in separation of epidermal layer from basal membrane
What are the immediate responses of cryosurgery?
- Erythema
2. Hyperemia
What are the responses to cryosurgery within 24-48 hours?
- Edema
2. Blister formation
What are the responses to cryosurgery within 72 hours?
- Treated lesion becomes bloodless
- Crust begins to form
- Crust then gradually withers away over next several days
- Re-epithelialization occurs from outer margin inward
What are the benign indications for cryosurgery?
- Verrucae/ Condyloma acuminatum
- Seborrhea keratosis
- Lentigo
4, Molluscum contagiosum - Dermatofibroma
- Hypertropic scars
- Acrochordon
What are the precancerous and cancerous indications for cryosurgery?
- Actinic keratosis
- Malignant: only by specialist
A. BCC
B. SCC in situ
C. Lentigo maligna
If dx is not clear, a biopsy should be performed
What are the absolute contraindications to cryosurgery?
- Sensitivity or adverse reaction to cryosurgery
- Any undiagnosed lesion in which malignancy is suspected- Refer
- Melanoma
- Nonacceptance of possibility of skin pigment changes
- Areas of compromised circulation
- Recurrent or Sclerosing BCC
What are the relative contraindications to cryosurgery?
- Dark complexion
- An extremity w/ vascular compromise
- Cryoglobulinemia
- Autoimmune disorder
- Raynaud’s disease
- Areas around hair, ie eyebrows
- Body area w/ superficial nerves (ie angle of jaw, lateral aspects of digits, ulnar fossa of elbow)
What equipment is needed for cryotherapy?
- Various delivery devices
- Assorted cryo-probe tips
- K-Y jelly
What are the possible delivery devices for cryosurgery?
- Brymill Cryogun (liquid nitrogen)
- Verruca Freeze (
- Histofreezer
What is the method of application for brymill cryogun?
- Contact probes or spray-tipped nozzles can be used
2. Perpendicular spray most effective
How is the pt prepped for cryosurgery/
- Informed consent
- Discuss Pros/Cons
- Inform pt that they will feel discomfort/pain which may last up to 20-30 mins
- Pt supine for safer treatment environment
- Topical anesthestics may be used as cream or gel prior to tx
- Inform pt that it is common for blistering to occur