Kalabakas AA, Porter AJ, Mule L, Birch MJ, Pollock DJ, Swain CP. Design of a microwave system for endoscopy: an experimental study of energy, tissue contact, and hemostatic efficacy.
Gastroenterology 1993;
104:680-9. [PMID:
8440429 DOI:
10.1016/0016-5085(93)91002-y]
[Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND
A microwave generator and delivery system for endoscopic use was built. Using a 650-W, 2450-MHz magnetron, 0-160 W were generated from the tip of a 180-cm flexible coaxial cable (2.1 mm diameter).
METHODS
Three methods of achieving hemostasis with microwaves were identified studying standard bleeding canine ulcers: (1) interstitial method: inserting the coaxial tip into the tissue and heating slowly until bleeding stopped; (2) contact method: tip held in contact, light pressure applied; (3) noncontact method: microwave-induced sparking (dielectric breakdown) with tip held 1 mm from tissue.
RESULTS
Studies of optimal energy levels for hemostasis showed that high power (70 W) noncontact methods required significantly less energy to stop bleeding than contact or interstitial methods. The noncontact method was more effective than the contact method, stopping 20 of 20 bleeding ulcers vs. 10 of 20 (P < 0.001) and was more rapidly effective causing less tissue damage (P < 0.05) than the interstitial method.
CONCLUSIONS
In a randomized comparison using a non-contact method, microwave coagulation was superior (P < 0.001) to a polidocanol 1% + adrenaline 1:10,000 injection and control treatment stopping 40 of 40 vs. 0 of 20 and 0 of 20 standard bleeding ulcers. Microwaves stopped bleeding from 10 of 10 severed mesenteric vessels, whereas injection was ineffective (0 of 10, P < 0.001). Microwaves look promising for hemostasis at flexible endoscopy.
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