title: Histological characteristics of collagen denaturation and injuries in bipolar radiofrequency-induced colonic anastomoses.
abstract: Bipolar radiofrequency-induced thermo-fusion has been explored as an advanced surgical method for intestinal anastomoses; however, the histological characteristics of collagen denaturation and injuries arising from this process remain unclear. The aim of this study was to investigate the microcosmic changes and tissue damage of fusion regions with various parameters of injury. Ex vivo colons of pigs were fused serosa-serosa on two carrier rings, which were installed on a homemade anastomotic device. Five levels of compressive pressure from 171 to 313 kPa were applied for 5s to fuse the colons under radiofrequency power of 160 W, and then the collagen denaturation of the fused region was examined by transmission electron microscopy. Light microscopy was utilized to observe histological slices that were stained with picrosirius red in order to visualize the tissue injuries under two levels of radiofrequency power (120 vs. 140 W) and operation time (5 vs. 10s). Transmission electron micrographs showed that increased compressive pressure led to thicker denatured collagen fibrils and wider gaps between each collagen fibril. Serosa adhesion regions appeared abundant in collagen. No histological differences were observed when 120 W of power was applied for 5 and 10s. Significant muscle cracking occurred when colons were fused using 140 W for 5s. When the operation time was extended to 10s, 140 W led to tight fusion and less splitting on muscles. These results suggest that higher compressive pressure results in more severe collagen unfolding and also reduces collagen crosslinking in fused colons. Improved radiofrequency power along with operation time could avoid tissue injury upon radiofrequency-induced colonic anastomoses.
authors.affiliation: Shanghai Institute for Minimally Invasive Therapy, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
authors.forename: Lingxi
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Colorectal Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China; Department of Surgical Oncology, Fujian Provincial Cancer Hospital, Teaching Hospital of Fujian Medical University, Fuzhou 350001, China.
authors.forename: Changhua
authors.initials: C
authors.lastname: Zhuo
authors.affiliation: Shanghai Institute for Minimally Invasive Therapy, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China. Electronic address: csong@usst.edu.cn.
authors.forename: Chengli
authors.initials: C
authors.lastname: Song
authors.affiliation: Department of Colorectal Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China. Electronic address: lxx1149@163.com.
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Li
authors.affiliation: Shanghai Institute for Minimally Invasive Therapy, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Colorectal Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
authors.forename: Debing
authors.initials: D
authors.lastname: Shi
mesh_terms: D000714:Anastomosis, Surgical / Q000009:adverse effects / Q000379:methods; D000818:Animals; D003094:Collagen / Q000378:metabolism*; D003106:Colon / Q000378:metabolism / Q000473:pathology* / Q000601:surgery*; D004598:Electrosurgery / Q000009:adverse effects*; D005260:Female; D013552:Swine
chemical_list: D003094:Collagen
keywords: Collagen denaturation; Colonic anastomoses; Histological injuries; Radiofrequency