What information should be included in the informed consent for using liquid nitrogen (LN) for wart removal?

Informed Consent Information for Liquid Nitrogen Wart Removal

The informed consent for liquid nitrogen (cryotherapy) wart removal should include information about the procedure, expected outcomes, potential side effects, alternative treatments, and post-treatment care instructions to ensure patients are fully informed about the treatment. 1

Procedure Information

• Liquid nitrogen is applied to warts at extremely cold temperatures (approximately -80°C to -196°C) to destroy wart tissue 2, 3
• The application method may involve either a cotton wool bud or spray technique, both of which have similar efficacy rates 4
• Treatment typically involves applying liquid nitrogen until an ice ball forms around the wart with a 2mm margin 4
• Multiple treatment sessions may be required, typically at 1-2 week intervals 1, 5
• For plantar warts, a double freeze-thaw cycle may be used after paring down the wart 4

Expected Outcomes

• Complete clearance of warts may require 1-3 treatments, with cure rates ranging from 39-70% depending on wart type and treatment protocol 5, 3
• Warts present for less than 6 months have significantly higher clearance rates (approximately 84%) compared to longer-standing warts (39%) 4
• Common warts respond better to cryotherapy (49% cure rate) compared to plantar warts, which may be more resistant 5
• Recurrence is possible, with most recurrences occurring within the first 3 months after treatment 1

Potential Side Effects and Risks

• Pain during and after the procedure is common and expected 2
• Blistering at the treatment site is a normal reaction and part of the healing process 2
• Skin discoloration (hypopigmentation or hyperpigmentation) may occur, especially in darker skin tones 1
• Scarring is possible, particularly if treatment extends too deeply into the dermis 1
• Nerve damage is a rare but possible complication, especially in areas with superficial nerves 1
• For specific anatomical locations:
  • Vaginal application carries risk of perforation and fistula formation (cryoprobes should not be used in this area) 1
  • Treatment near nail beds may cause nail deformity 6

Special Considerations

• Pregnancy: Safety during pregnancy has not been well established for some wart treatments, though cryotherapy is generally considered safer than chemical alternatives 1
• The procedure is contraindicated in patients with:
  • Poor circulation to extremities
  • Cold intolerance disorders like Raynaud's disease
  • Cryoglobulinemia
  • Cold urticaria 1
• Patients with diabetes or peripheral vascular disease may have delayed healing 1

Post-Treatment Instructions

• The treated area may be painful, red, and swollen for several days 2
• Blisters may form within 24 hours and should be left intact if possible 2
• Keep the area clean and dry; washing is permitted but avoid scrubbing 1
• A scab will form and should be allowed to fall off naturally (typically within 1-2 weeks) 1
• Return for follow-up as recommended, typically in 2-4 weeks for assessment and possible retreatment 1
• Contact healthcare provider if signs of infection develop (increasing pain, warmth, redness, swelling, discharge) 1

Alternative Treatment Options

• Patient should be informed of alternative treatment options including:
  • Salicylic acid preparations (24% cure rate) 5
  • Surgical removal 1
  • Electrocautery 1
  • Laser therapy 1
  • Immunotherapy options 1
  • Watchful waiting (16% spontaneous resolution) 5

Treatment Duration and Efficacy

• A 10-second sustained freeze is more effective (64% clearance) than traditional brief freezing (39% clearance) but causes more pain and blistering 2
• Complete resolution may take multiple treatments, typically up to three sessions 3
• Warts may persist despite treatment, requiring alternative approaches 1