title: Experimental analyses of the cavitation generated by ultrasonically activated surgical devices.
abstract: OBJECTIVE
  Recently, the incidence of postoperative pancreatic leakage has been reported to have significantly increased after laparoscopic gastrectomy for gastric cancers in comparison to open surgery. Although their lateral thermal spread has been shown to be smaller than that of other electrosurgical devices, ultrasonically activated surgical devices (USADs) have been suggested as one of the causes. We therefore hypothesized that cavitation generated by USADs could cause injuries to pancreatic tissue. Our retrospective study showed that the amylase activity in the drainage fluid of patients in whom surgery was performed using a USAD with a curved blade was significantly higher than that in patients in whom surgery was performed using a USAD with a straight blade. We therefore focused on the effects of straight and curved USAD blades.
  
  
  METHODS
  The distribution of microbubbles generated in degassed water, which produce mechanical and biological tissue destructive forces, was measured and compared between the two types of USAD.
  
  
  RESULTS
  More microbubbles were found to be generated from the side aspect of the curved blade, and the mechanical and biological destructive forces were found to be significantly higher than those generated by the side aspect of the straight blade.
  
  
  CONCLUSIONS
  These findings strongly suggest that cavitation generated by USADs could injure pancreatic tissues in the clinical cases. Surgeons should be aware of these properties of devices to achieve safe and secure surgeries.
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Tao
authors.initials: T
authors.lastname: Gao
authors.affiliation: Graduate School of Engineering, Chiba University, Chiba, Japan.
authors.forename: Bik Ee
authors.initials: BE
authors.lastname: Lau
authors.affiliation: Center for Frontier Medical Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Hanari
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Gunji
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kano
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Hisahiro
authors.initials: H
authors.lastname: Matsubara
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. hhayashi@faculty.chiba-u.jp.|Center for Frontier Medical Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan. hhayashi@faculty.chiba-u.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004598:Electrosurgery / Q000009:adverse effects* / Q000295:instrumentation*; D005260:Female; D005743:Gastrectomy / Q000295:instrumentation*; D006801:Humans; D007049:Iatrogenic Disease / Q000517:prevention & control; D010535:Laparoscopy / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000293:injuries*; D011183:Postoperative Complications / Q000209:etiology* / Q000517:prevention & control; D012189:Retrospective Studies; D013525:Surgical Instruments / Q000009:adverse effects*; D014465:Ultrasonics / Q000295:instrumentation*
keywords: Energy device; Laparoscopic gastrectomy; Pancreatic injury