cryosurgery(redirected from thermal caustics)
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destruction of tissue by application of extreme cold; silver nitrate and solid carbon dioxide are commonly used. Uses include treatment of certain malignant lesions of the skin and mucous membranes, early removal of malignant lesions of the uterine cervix, and treatment of tumors that cannot be handled with traditional surgical techniques.
An operation using freezing temperature (achieved by liquid nitrogen or carbon dioxide) as an independent agent or in an instrument to destroy tissue.
cryosurgery/cryo·sur·gery/ (kri″o-ser´jer-e) the destruction of tissue by application of extreme cold.
The selective exposure of tissues to extreme cold, often by applying a probe containing liquid nitrogen, to bring about the destruction or elimination of abnormal cells.
cry′o·sur′geon (-jən) n.
cry′o·sur′gi·cal (-jĭ-kəl) adj.
Etymology: Gk, kryos + cheirourgos
use of subfreezing temperature to destroy tissue. Cryosurgery is performed in the destruction of the ganglion of nerve cells in the thalamus in the treatment of Parkinson's disease, in the destruction of the pituitary gland to halt the progress of some kinds of metastatic cancer, and in the treatment of various cancers and lesions of the skin. The process is also used in ophthalmology to cause the edges of a detached retina to heal and to remove cataracts. The coolant is circulated through a metal probe, chilling it to as low as -160° C (-256° F), depending on the chemical used. The moist tissues adhere to the cold metal of the probe and freeze. Cells are dehydrated as their membranes burst; eventually they are discarded or absorbed by the body. No specific postoperative nursing care is required.
cryosurgeryAmbulatory surgery A technique that uses liquid nitrogen to freeze and destroy malignancy–eg, CA of uterine cervix, prostate CA. Cf Cone biopsy, Radical prostatectomy Cardiology A technique used to modify AV node conduction in Pts with treatment-refractory AV node reentrant tachycardia See Cryotherapy.
An operation using freezing temperatures (achieved by liquid nitrogen or carbon dioxide) to destroy tissue.
cryosurgeryControlled tissue destruction by low temperatures, usually by means of cryoprobes by which cold can be applied with precision. The method is used in the treatment of PARKINSON'S DISEASE, cancer of the PROSTATE and other organs, RETINAL DETACHMENT and CATARACT removal.
In prostatectomy, the use of a very low-temperature probe to freeze and thereby destroy prostatic tissue.
cryosurgeryapplication of profoundly low temperatures to cause controlled tissue destruction; cells subject to a freeze-thaw process undergo lysis and membrane rupture, exposing intracellular viral particles to the immune system (Table 1 and see Table 2)
|Indications||Single isolated skin lesions, after debridement of overlying callosity|
|Contraindications||Patients with peripheral articular disease, Raynaud's or any other cause of reduced tissue perfusion or reduced healing|
Patients with a low pain threshold
Lesions that overlie joints, or in areas where there is little or reduced fibrofatty padding
|Keratolytic/caustic agent||Indicated use|
|Whitfield's ointment (3% salicylic acid and 6% benzoic acid in white soft paraffin)||Treatment of mild tinea pedis|
|5% salicylic acid ointment||Applied daily for 7 days to soften hyperkeratosis and facilitate its removal|
|12% salicylic acid in collodion||Macerating agent; painted over callosity and left in situ for 7 days, to assist removal of heavy callosity|
|20-40% salicylic acid plaster||Applied topically and left in situ for 1-2 days to aid removal of corns|
|40-70% salicylic acid ointment||Applied topically in a cavitied pad and left in situ for 7 days for verruca treatment; the lesion should be masked|
|Calmurid cream (10% urea)||To hydrate anhidrotic skin; applied daily to treat dyskeratosis|
|40% urea cream||A strongly keratolytic agent, applied under an occlusive dressing and left in situ for 7 days, to soften, macerate and aid the reduction and removal of hypertrophied nails in patients who are unsuitable for nail avulsion|
|Monochloroacetic acid||A deeply penetrating caustic that is painful in use Applied, retained in situ and reviewed within 3-7 days, for the treatment of verrucae:|
1. as a saturated solution to the lesion
2. as a tiny crystal strapped over a masked lesion
3. as a tiny crystal embedded in 40-70% salicylic acid retained by a cavitied pad
|Trichloroacetic acid||A self-limiting caustic with a superficial action|
Applied directly to the verruca, after initial scalpel debridement of the lesion
May be used in conjunction with 75-95% silver nitrate (see below) as a diagnostic or a final treatment of verrucae
|75-95% Silver nitrate||A self-limiting caustic with a superficial action, causing a dark brown discoloration of the skin to which it is applied; it is used for the treatment of shallow or mosaic verrucae.|
Note: Some patients show an idiosyncratic local sensitivity or inflammatory reaction to applied silver nitrate
1. Applied directly to the lesion, after overlying callosity has been debrided off
2. Applied directly to the lesion in alternating layers with trichloroacetic acid
3. As a diagnostic aid to identify verrucous tissue; viral-infected skin cells show up as bright white dots within a few moments of the application of the layers of silver nitrate and trichloroacetic acid
|Potassium hydroxide (KOH)||A powerful keratolytic caustic with a great affinity for water that penetrates deeply dissolving precipitated protein; used to destroy soft tissues|
1. Overlying hyperkeratosis is debrided off the verruca and the foot is immersed in water for 5 minutes to hydrate the skin, then dried; a KOH pellet is rubbed into the lesion; the foot is reimmersed in water and the jelly-like material formed by the KOH on the lesion surface is debrided off. The process is repeated once or twice until the lesion appears to have gone, then glacial acetic acid is applied to neutralize the KOH
2. A similar protocol may be used to ablate nail matrix after removal of the overlying section of nail plate
3. KOH 5% liquid applied to heavy callosity and left in situ for 5 minutes softens heavy callosity to ease its removal
|Pyrogallol (pyrogallic acid)||A powerful analgesic, non-self-limiting, caustic reducing agent. It may be used in the treatment of recalcitrant verrucae or neurovascular corns in areas of skin overlying a healthy layer of fibrofatty padding. It should only be used with great caution as its action continues after application has ceased and can lead to severe tissue breakdown that is slow to heal. It is incompatible with alkalis, iron salts, oxidizing agents and ammonium salts|
1. 20% pyrogallol ointment for the treatment of neurovascular corns
2. 40% pyrogallol ointment for the treatment of VP
3. WP ointment (20% pyrogallol, 20% wheat germ oil) for the treatment of tough, fibrous, hyperkeratotic plantar lesions
|Phenol||An analgesic, corrosive caustic. It is used as an 80% solution (liquefied phenol) to destroy soft-tissue lesions such as VP, or nail matrices (three applications, each of 1 minute duration). Its action is quenched by dilution with IMS or isopropyl alcohol. Healing is delayed for several weeks after its application|
|Glacial acetic acid||A weakly acidic mild caustic that is crystalline at 14°C|
1. As a paint to hard or vascular corns, or VP (return period 14-21 days)
2. As a paint to VP, alternating with silver nitrate 75% (in a similar manner to trichloroacetic acid)
3. To neutralize KOH (see above: KOH, point 1)
|Nitric acid||A powerful analgesic oxidizing caustic agent with a superficial action that offers a 'one-off' VP treatment|
1. Applied to VP with a glass rod and left in situ for 5 minutes, followed by phenol solution 10%; the skin stains bright yellow
2. The lesion is saturated with phenol solution 5% for 5 minutes, then with nitric acid for 20-30 seconds, then once again with phenol solution 5%
|Strong iodine solution (iodine solution 10%; iodine fortis)||A strong astringent and vesicant agent. It is incompatible with many topical medicaments, and can cause sensitivity reactions in some patients|
1. to shrink nail tufts
2. to shrink hypergranulation tissue
|Formaldehyde||A strongly astringent and antiseptic agent used in the treatment of VPs (the skin surrounding the lesion should be protected with petroleum jelly; sensitivity is likely)|
1. 10% formaldehyde in collodion, painted on daily
2. 36% formaldehyde solution, painted on daily
|Cryosurgery||The topical application of liquid nitrogen (at -196°C) or nitrous oxide (at -88.5°C) to destroy small soft-tissue lesions; the cell cytoplasm must be reduced to and maintained at -24°C or lower for at least 1 minute, and repeated for two further freezing episodes between which the area has been allowed to thaw. Cryosurgery is more effective when any overlying hyperkeratosis is removed before freezing|
|Hyfrecation||Tissue destruction by initial fulguration (outlining and superficial charring) of the lesion by the application of high-frequency electrical energy), then electrodesiccation (electrocautery) of the lesion by the release of electrical energy whilst the probe is inserted into the lesion|
|Electrosurgery||Tissue removal using high-frequency energy waves to incise through tissue|
Note: Please also refer to the text entries for each listed agent.
IMS, industrial methylated spirit; VP, verrucae pedis.
n surgical operation in which a metal probe (chilled to at least −160°C) is therapeutically applied to destroyed tissue.
An operation using freezing temperature (achieved by liquid nitrogen or carbon dioxide) to destroy tissue.
n the use of subfreezing temperature to destroy tissue. Cryosurgery is used to cause the edges of a detached retina to heal, to remove cataracts, and in the treatment of Parkinson's disease.
the destruction of tissue by application of extreme cold. Used in the treatment of certain malignant lesions of the skin and mucous membranes, anorectal lesions and in the removal of cataracts.