title: Laparoscopic mechanical fixation devices: does firing angle matter?
abstract: BACKGROUND
  A variety of permanent and absorbable tacks are available for mesh fixation during laparoscopic hernia repairs. Although manufacturers recommend deploying tacks perpendicular to the tissue, achieving this can sometimes be challenging. This study aimed to analyze comparatively the effects of angled deployment among commonly used tacks.
  
  
  METHODS
  A piece of composite mesh was fixed to the peritoneal surface of a pig with a single tack fired at either a perpendicular (90°) or acute (30°) angle. A lap-shear test was performed to determine fixation strength. Two permanent tacks (a titanium spiral tack: Protack [PT]; and a hollow screw fastener: PermaFix [PF]) and three absorbable tackers (a solid screw: Absorbatack [AT]; a hollow screw fastener: SorbaFix [SF]; and a strap: SecurStrap [SS]) were challenged. A total of 16 samples were performed for each device at each angle. A nonabsorbable transfascial suture was used as a control condition.
  
  
  RESULTS
  Transabdominal sutures had the maximum acute tensile strength (ATS) (29.9 ± 5.5 N). Protack at both 90° and 30° performed significantly better than absorbable tacks (p < 0.01). No significant difference was found among absorbable tacks at 90°. When the same construct was compared at different angles, SS and SF performance was not affected (p = 0.07 and 0.2, respectively). In contrast, PT and AT had significantly reduced fixation strength (p = 0.003 and 0.004, respectively). However, PT fired at an acute angle had fixation equal to that of absorbable tacks fired perpendicularly.
  
  
  CONCLUSIONS
  Transabdominal sutures performed better than tacks in the acute setting. No absorbable fixation device demonstrated superior efficacy within its class. Spiral titanium tacks provided better fixation than absorbable tacks at both perpendicular and acute angles. Moreover, titanium spiral tacks deployed at 30° performed equal to or better than absorbable tacks fired perpendicularly to the tissue. It appears that spiral titanium tacks should be strongly considered for cases in which perpendicular tack deployment cannot be achieved.
authors.affiliation: Case Comprehensive Hernia Center, University Hospitals Case Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106-5047, USA.
authors.forename: Emmanuel E
authors.initials: EE
authors.lastname: Sadava
authors.forename: David M
authors.initials: DM
authors.lastname: Krpata
authors.forename: Yue
authors.initials: Y
authors.lastname: Gao
authors.forename: Steve
authors.initials: S
authors.lastname: Schomisch
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rosen
authors.forename: Yuri W
authors.initials: YW
authors.lastname: Novitsky
mesh_terms: D000818:Animals; D004867:Equipment Design; D006555:Hernia, Ventral / Q000601:surgery; D059685:Herniorrhaphy / Q000295:instrumentation; D010535:Laparoscopy / Q000295:instrumentation*; D013526:Surgical Mesh; D013528:Surgical Staplers; D034421:Sus scrofa; D013537:Sutures; D013718:Tensile Strength