Comparison of holding strength of suture anchors on human renal capsule

The use of surgical clips as suture anchors has made laparoscopic partial nephrectomy (LPN) technically simpler by eliminating the need for intracorporeal knot tying. However, the holding strength of these clips has not been analyzed in the human kidney. Therefore, the safety of utilizing suture anchors is unknown as the potential for clip slippage or renal capsular tears during LPN could result in postoperative complications including hemorrhage and urinoma formation. With the above in mind, we sought to compare the ability of Lapra-Ty clips and Hem-o-lok clips to function as suture anchors on human renal capsule.

Fresh human cadaveric kidneys with intact renal capsules were obtained. A Lapra-Ty clip (Ethicon, Cincinnati, OH) or a Hem-o-lok clip (Weck, Raleigh, NC) was secured to a no. 1 Vicryl suture (Ethicon) with and without a knot, as is typically utilized during the performance of LPN. The suture was then placed through the renal capsule and parenchyma and attached to an Imada Mechanical Force Tester (Imada, Northbrook, IL). The amount of force required both to violate the renal capsule and to dislodge the clip was recorded separately.

Six Lapra-Ty clips and six Hem-o-lok clips were tested. The mean force in newtons required to violate the renal capsule for the Lapra-Ty group was 7.33 N and for the Hem-o-lok group was 22.08 N (p < 0.001). The mean force required to dislodge the clip from the suture for the Lapra-Ty group was 9.0 N and for the Hem-o-lok group was 3.4 N (p < 0.001). When two Hem-o-lok clips were placed on the suture in series, the mean force required to dislodge the clips was 10.6 N.

When compared with Lapra-Ty clips, using two Hem-o-lok clips may provide a more secure and cost-effective method to anchor sutures on human renal capsule when performing LPN.