An ex-vivo evaluation of the application and strength of a novel laparoscopic knot substitute device

Intracorporeal suturing can be challenging, especially in the case of laparoscopic partial nephrectomy. During these procedures, suturing must reapproximate renal tissue to achieve hemostasis but not tear through tissue. We present a new device, the ANPA Suturelock, which can be adjusted to increase or decrease suture tension, optimizing tissue apposition.

Two participants (one experienced laparoscopist, one junior resident) completed the protocol. A laparoscopic trainer was used to secure 2-0 polyglactin suture ends in rubber foam using five of each of the following: Traditional laparoscopic suture knots (one surgeon's knot and two square knots), square-to-slip knots, Weston extracorporeal knots, ANPA Suturelock, Lapra-Ty devices, Hem-O-Lock clips, and titanium clips. Tensile strength of each knot and knot substitute was measured using an Instron machine (Instron, Norwood, MA). Time to secure the two suture ends was measured for ANPA Suturelock and laparoscopic surgeon's knot. Statistical analysis was performed using the Student t test.

Mean tensile strength of the three knot-tying methods was 53.0 newtons (N) while that of the four knot substitute devices was 8.3 N (P < 0.001). Each of the three individual knot-tying methods had significantly greater tensile strength than any of the knot substitutes (P < 0.001 for all). Of the knot-tying methods, the surgeon's knot was the strongest (mean tensile strength 63.2 N) and was significantly stronger than square-to-slip and Weston extracorporeal knots (39.1 N and 48.4 N, respectively, P < 0.05 for both). Of the knot substitutes, ANPA Suturelock (mean tensile strength 14.7 N) was significantly stronger than Lapra-Ty (6.1 N), Hem-O-Lock (5.4 N), and titanium clip (3.0 N) (P < 0.01 for all). When compared with a laparoscopic surgeon's knot, the time to securing the ANPA Suturelock was significantly quicker for a third year resident (106 sec vs 38 sec, P < 0.001) and an experienced laparoscopist (75 sec vs 23 sec, P = 0.02).

The tensile strengths of traditional knot-tying techniques were greater than that of any knot substitute device. The ANPA Suturelock provided the greatest tensile strength of any knot substitute. The time to secure a knot using the ANPA device was also significantly quicker than tying a standard surgeon's knot.