Cryosurgery

Question 1

What are the cryogenic agents?

Answer 1

Liquid nitrogen, NO, CO2

Question 2

What temperature does benign tissue destruction occur at? Malignant tissue?

Answer 2

1. Tissue destruction occurs between -10 and -20C

2. Malignant cells are completely destroyed between -40 and -50 C

Question 3

What are the portable canisters used for?

Answer 3

Portable canisters are only for benign lesions (propane, dimethyl ether)

Question 4

What is the physiology of cryosurgery?

Answer 4

Freezing of epidermis results in separation of epidermal layer from basal membrane

Question 5

What are the immediate responses of cryosurgery?

Answer 5

1. Erythema

2. Hyperemia

Question 6

What are the responses to cryosurgery within 24-48 hours?

Answer 6

1. Edema

2. Blister formation

Question 7

What are the responses to cryosurgery within 72 hours?

Answer 7

1. Treated lesion becomes bloodless
2. Crust begins to form
3. Crust then gradually withers away over next several days
4. Re-epithelialization occurs from outer margin inward

Question 8

What are the benign indications for cryosurgery?

Answer 8

1. Verrucae/ Condyloma acuminatum
2. Seborrhea keratosis
3. Lentigo
   4, Molluscum contagiosum
4. Dermatofibroma
5. Hypertropic scars
6. Acrochordon

Question 9

What are the precancerous and cancerous indications for cryosurgery?

Answer 9

1. Actinic keratosis
2. Malignant: only by specialist
   A. BCC
   B. SCC in situ
   C. Lentigo maligna
   If dx is not clear, a biopsy should be performed

Question 10

What are the absolute contraindications to cryosurgery?

Answer 10

1. Sensitivity or adverse reaction to cryosurgery
2. Any undiagnosed lesion in which malignancy is suspected- Refer
3. Melanoma
4. Nonacceptance of possibility of skin pigment changes
5. Areas of compromised circulation
6. Recurrent or Sclerosing BCC

Question 11

What are the relative contraindications to cryosurgery?

Answer 11

1. Dark complexion
2. An extremity w/ vascular compromise
3. Cryoglobulinemia
4. Autoimmune disorder
5. Raynaud’s disease
6. Areas around hair, ie eyebrows
7. Body area w/ superficial nerves (ie angle of jaw, lateral aspects of digits, ulnar fossa of elbow)

Question 12

What equipment is needed for cryotherapy?

Answer 12

1. Various delivery devices
2. Assorted cryo-probe tips
3. K-Y jelly

Question 13

What are the possible delivery devices for cryosurgery?

Answer 13

1. Brymill Cryogun (liquid nitrogen)
2. Verruca Freeze (
3. Histofreezer

Question 14

What is the method of application for brymill cryogun?

Answer 14

1. Contact probes or spray-tipped nozzles can be used

2. Perpendicular spray most effective

Question 15

How is the pt prepped for cryosurgery/

Answer 15

1. Informed consent
2. Discuss Pros/Cons
3. Inform pt that they will feel discomfort/pain which may last up to 20-30 mins
4. Pt supine for safer treatment environment
5. Topical anesthestics may be used as cream or gel prior to tx
6. Inform pt that it is common for blistering to occur

Question 16

What is the method of application for verruca freeze?

Answer 16

1. Hold spray tip 1-2 cm from lesion surface and gently squeeze trigger mechanism
2. Apply spray in a pulsatile rotary spiral rather than continuous
3. May use disposable ear cone to confine spray

Question 17

What are the general guidelines regarding the halo for effective destruction of the lesion?

Answer 17

In general, a halo of 1 mm around the base of lesion should be produced to cause effective destruction of many benign lesions

Question 18

What is the recommended halo size for Verrucae/actinic keratosis/acroch?

Answer 18

1-2mm

Question 19

What is the recommended halo size for Molluscum contagiosum/seborrheic keratosis?

Answer 19

1 mm

Question 20

What is the recommended halo size for Lentigo/dermatofibroma/sebaceous hyperplasia?

Answer 20

0-1 mm

Question 21

What is the depth of the freeze?

Answer 21

The depth of the freeze is estimated to be approx 1.5 times the lateral spread of the freeze (the halo)

Question 22

How should a raised lesion be treated?

Answer 22

For a lesion that is raised, the lesion should be treated w/ continuous freeze, called an ice ball, that encompasses the lesion (start at distal most part of lesion)

Question 23

What is the most effective destruction technique?

Answer 23

Freeze rapidly, thaw, re-freeze

Question 24

What is recommended freeze time for Plantar warts/skin tags/seb keratoses (after debridement)?

Answer 24

40 sec

Question 25

What is recommended freeze time for molluscum contagiosum?

Answer 25

20 sec

Question 26

What is recommended freeze time for actinic keratosis (facial)?

Answer 26

15 sec

Question 27

What is recommended freeze time for actinic keratosis (non-facial)?

Answer 27

40 sec

Question 28

What are the danger sites for cryosurgery?

Answer 28

1. eyes 2. ears 3. side of mouth

Question 29

What are the potential complications of cryosurgery?

Answer 29

1. Pigment cells/hair cells may be destroyed 2. Area poor circulation susceptible to prolonged ulcer formation 3. Tissue pathology documentation is not possible 4. Peripheral neuropathy can result when areas adjacent to nerves are frozen 5. Overtreating a lesion may result in unnecessarily destroying healthy tissue and creating scars and hypopigmentation 6. Undertreated lesions can always be re-treated at a later date if needed

Question 30

What pt education needs to be provided for cryosurgery?

Answer 30

1. Edema/erythema are to be expected and pain may be uncomfortable enough for modifying activities A. With plantar warts, may need to refrain from running or walking 2. Tell patient to watch for signs of infection and contact if fever, chills, increased pain or redness or if blister is more severe than the patient can tolerate 3. Inform pt that it is possible to have redness at site for several days or even weeks (which may not necessarily mean it is infected)