Staple pull-out strength in an animal model of Cooper's ligament.
OBJECTIVE
To understand the effect of staple number, orientation, and configuration on pull-out strength in an animal model of Cooper's ligament, and compare it with force to knot failure or suture breakage.


METHODS
Comparative study (Canadian Task Force classification I).


METHODS
Ethicon Endo-Surgery Institute, Cincinnati, Ohio.


METHODS
Fibrous connective tissues from bovine ischia were the tissue model.


METHODS
Specimens were fixed in a cement-plaster compound and mounted in a tensiometer. Endoscopic staples were used to hold a loop of 0-braided polyester suture to the tissue.


RESULTS
The suture loop was pulled perpendicularly away from tissue at a constant rate of 2.1 mm/second and peak force to staple pull-out was recorded. Two staple orientations and four staple configurations were studied. Tests were applied in a factorial arrangement. Ten-millimeter stitches of 0-braided polyester suture in the model were also tested. Maximum force to staple pull-out depended on staple number, orientation, and configuration. Peak force required to remove two staples was significantly higher than that to remove one. Spacing between two staples was less important. Pull-out strength was significantly higher when staples were placed parallel to tissue fibers. Stitches placed perpendicular to fibers failed at the knot or by suture breakage with a mean force approximately two times the peak force to remove two staples.


CONCLUSIONS
Two staples placed 2 to 5 mm apart parallel to tissue fibers resulted in the greatest pull-out strength of studied configurations.
Department of Gynecology and Obstetrics, Cleveland Clinic Foundation, Ohio, USA.
M F
MF
Paraiso
J F
JF
Cummings
M D
MD
Walters
D000818:Animals; D002417:Cattle; D010535:Laparoscopy; D008022:Ligaments / Q000601:surgery*; D013536:Suture Techniques; D013537:Sutures; D013718:Tensile Strength; D001743:Urinary Bladder / Q000601:surgery