In vivo characterization of colonic thermal injury caused by argon plasma coagulation.
BACKGROUND
Argon plasma coagulation has been rapidly accepted for endoscopic obliteration of vascular lesions and superficial tumors. Depth of injury is thought to be limited through preferential discharge of energy to nondesiccated tissue. However, argon plasma coagulation-induced injury has not been well characterized. The aim of this study was to characterize argon plasma coagulation-induced colonic injury by using a porcine model.


METHODS
Laparotomy was performed in 6 female swine and the colon exteriorized with the subjects under general anesthesia. Lesions were made with an argon plasma coagulation probe held perpendicular and 2 mm from the mucosa. Variables studied were as follows: power (45 W, 60 W, and 75 W) and duration (1, 2, or 3 seconds; n = 11 for each power/duration combination). Injury was graded as either superficial or deep, involving the muscularis propria.


RESULTS
Circular muscle layer injury correlated closely with power (p = 0.02), duration (p = 0.001), and total energy delivered (r = 0.977). Longitudinal muscle damage was associated with duration of burn (p = 0.001) and total energy delivered (r = 0.855), but correlated poorly with power (p = 0.40). No perforations occurred. Submucosal injection of saline solution had a protective effect with reductions in circular (90% to 10%, p = 0.002) and longitudinal muscle injury (50% to 0%, p = 0.1).


CONCLUSIONS
Injury to the muscularis propria occurs at recommended settings for argon plasma coagulation. Injury correlates with power setting, duration of burn, and total energy delivery. Protective arcing to nondesiccated tissue does not appear to be significant in vivo. Submucosal injection of saline solution protects against deep injury.
Norton
Ian D
ID
Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Wang
Linan
L
Levine
Susan A
SA
Burgart
Lawrence J
LJ
Hofmeister
Erik K
EK
Yacavone
Robert F
RF
Gostout
Christopher J
CJ
Petersen
Bret T
BT
D000818:Animals; D001128:Argon / Q000009:adverse effects*; D003029:Coagulants / Q000009:adverse effects*; D003106:Colon / Q000293:injuries* / Q000473:pathology; D004195:Disease Models, Animal; D004556:Electric Injuries / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control*; D004564:Electrocoagulation / Q000009:adverse effects*; D005260:Female; D007267:Injections; D007413:Intestinal Mucosa / Q000187:drug effects / Q000293:injuries* / Q000473:pathology; D012965:Sodium Chloride / Q000008:administration & dosage / Q000627:therapeutic use; D013552:Swine
D003029:Coagulants; D012965:Sodium Chloride; D001128:Argon