2.1) are all produced by cutting into a parent strand of smooth suture. This is readily apparent when closely observing the suture strand (Figure 2.9). This manufacturing technique reduces the strength of the suture. Therefore, it is important that the surgeon understands the tensile strength of the particular suture used. Relative strength compared to the parent strand is presented in Table 2.1. To date, the most commonly used barbed suture in veterinary medicine is the V‐loc™ (Medtronics, Covidien, Mansfield, MA). The V‐Loc suture size is denominated in relation to strength compared to a smooth suture. Thus, a 3‐0 V‐Loc is cut from a 2‐0 parent strand, but strength corresponds to a smooth 3‐0 suture [13]. More recently, a barbed suture with a solid core has been made available (Stratafix symmetric, Ethicon Johnson & Johnson Medical Devices, Somerville, NJ) which circumvents the issue of production‐induced reduced tensile strength.
Table 2.1 Features of currently available barbed suture.
| Barbed suture tradename | Manufacturer | Barb density/cm | Barb directional | Barb orientation | Anchoring system | Smooth suture size strength equivalence of size 3‐0 barbedb |
|---|---|---|---|---|---|---|
| Quill | Angiotech Pharm. | 10 | Bia | Helical | N/A | 4‐0 |
| V‐Loc | Medtronics | 20 | Uni | Dual‐angle | Welded loop | 3‐0b |
| Stratafix spiral | Ethicon | No info | Bi | Helical | N/A | 4‐0 |
| Stratafix symmetric | Ethicon | No info | Uni | Opposing | Fixation tab | N/A. Produced with solid core |
a Bidirectional sutures do not have a separate feature for anchoring, as they have needles at both suture ends, and suturing starts in the center of the incision and continues in bilateral direction.
b Most barbed sutures are produced by cutting into a solid suture strand, rendering the barbed suture weaker than the parent strand. V‐Loc has size denominated by equivalent strength to smooth suture (i.e. a 3‐0 V‐Loc is as strong as a 3‐0 smooth suture), whereas others are keeping the size denomination of the parent strand. The surgeon needs to be aware of this as a 3‐0 barbed suture may only have the tensile strength of a 4‐0 smooth suture.
Figure 2.9 V‐Loc 90 (A) and Quill Monoderm (B) barbed suture materials. V‐Loc 180 sutures feature unidirectional dual‐angle barbs with a suture needle on one end and a terminal welded loop on the other. Quill Monoderm sutures are double armed and feature bidirectional, helical, single‐angle barbs that emanate from the center of the strand.
Source: Reproduced with permission from Zaruby [13].
Intracorporeal Hand Suturing Technique
Please note that most descriptions in this section refer to right‐handed surgeons, preparing to take a right to left suture bite, for the purpose of increased readability. The instruments involved usually consist of a needle driver in the dominant hand (right in the examples here) and either a good‐quality grasper or a second needle driver in the non‐dominant (left) hand.
Cannula Placement
A fundamental difference between laparoscopic and open suturing is the restricted instrument mobility. The surgeon is confined by the cannula placement to a single arc of rotation perpendicular to the axis of the instrument. The cannula placement has to be as ideal as possible to make suturing easier. Figure 2.10 depicts the ideal cannula placement for knot tying. However, small animal surgeons often have to compromise on the classical triangulation due to animal size, and if suturing is done bilaterally.
Figure 2.10 Classical cannula triangulation to optimize instrument angles and working distances for laparoscopic knot tying and suturing.
An intercannula distance of at least 5 cm is desirable for the needle driver and accessory instrument. The working tips of these instruments should meet at oblique angles with each other at a relatively wide angle of 60° or more. If possible, the cannula for the right needle driver should be parallel to the suture line. The distance between cannula entrance and operative field should be approximately half of the length of the instrument (e.g., for 30‐cm instruments, the cannula should be placed 15 cm [∼6 in.] from the target field) [2]. The instruments and camera need to be directed in the same axis as the surgeon's view toward the screen to avoid mirrored vision.
Needle Introduction
The needle introduction method used depends on the type and size of needle, the size of the cannulas used, and the animal's size in relation to needle size. If the body wall thickness and needle size allow, the needle can simply be passed transcutaneously into the abdominal cavity anywhere in the surgically prepared area and be grasped intracorporeally with the needle driver (Figure 2.11). If so, the needle is ideally passed perpendicular to the dominant hand instrument axis so the needle can simply be grasped at the midpoint, and suturing ensues. Unidirectional barbed suture with a welded loop on the end is also easily introduced transabdominally. However, bidirectional barbed suture, or with a fixation tab, cannot be introduced transabdominally.
Figure 2.11 Transabdominal needle introduction. The needle is ideally introduced such that the needle holder (not visible in field) can grasp it without needing repositioning. An ideal introduction is noted here as the light reflects off the entire curvature of the needle. This is a cue for perpendicular orientation toward the right‐hand needle driver.
