alt="Schematic illustration of needle introduction through cannula site. (a) The cannula is removed, (b) threaded onto the instrument. The suture material is grasped 2–3 cm from the needle, and (c) introduced through the cannula site. The cannula is replaced."/>
Figure 2.12 Needle introduction through cannula site. (A) The cannula is removed, (B) threaded onto the instrument. The suture material is grasped 2–3 cm from the needle, and (C) introduced through the cannula site. The cannula is replaced.
If transabdominal introduction is prohibited by suture type or by animal size, as in most large animals, the needle and suture often need to be passed through the cannula or the cannula site. If the needle size is larger than the cannula allows, it may have to be passed through the cannula site with the cannula temporarily removed (Figure 2.12). The cannula is removed from the site while the assistant blocks gas exit, usually by digitally obstructing the defect. The instrument is placed through the cannula, and when it is exiting through the cannula end, the needle is either backloaded or the suture is grasped 2 cm from the swaged end and introduced into the abdomen through the cannula site (Figure 2.12). The cannula through which the instrument is positioned is then immediately replaced in the site to minimize gas leakage.
Needle Positioning
For surgeons experienced in traditional open suturing, the challenge of obtaining correct needle positioning in the needle driver often becomes a surprise. In fact, it has been shown that for novice laparoscopic surgeons, needle grasping and positioning within the needle driver are the most difficult and time‐consuming laparoscopic tasks [6].
In our experience, determining if an acceptable perpendicular position has been obtained is one of the major challenges. Novices often do not understand the magnitude of the needle displacement until suturing is attempted and found to be near impossible. Self‐righting needle drivers or 3D systems may be important aids, but we have found that most trainees will learn the cues for needle positioning reasonably fast. If using a standard 3/8 circle needle, one cue to correct perpendicular needle positioning is that the light source is reflected along the side of the needle (Figure 2.11).
When a perpendicular or near‐perpendicular needle position has been achieved, the suture bite is performed very similar to open surgery. Clockwise rotation of the instrument handle will allow tissue purchase within the arc of the needle.
Figure 2.13 Needle introduction through a cannula. (A). The suture is grasped with the left‐hand instrument (for the right‐handed surgeon) 2–3 cm from the swaged on end. The needle is then passed through the cannula. The cannula valve may need to be released when introducing to avoid disrupting the needle position. (B). When visible in the field, the right needle driver grasps the needle. The left instrument maintains grasp on the suture until needle position is as desired for the suture bite.
Figure 2.14 Needle position correction. (A). The needle is not perpendicular in the jaw of the needle driver. (B). The left‐hand instrument grasps the suture, and the right hand is releasing the ratchet to loosen up the grasp of the needle without letting go of it. Now the suture can be gently manipulated until the needle is in a more optimal position.
Figure 2.15 Needle introduction through a left‐sided cannula according to Brody et al. [11] (A). The needle is grasped with the left‐hand instrument backloaded (i.e., with the needle tip pointing in toward the shaft of the instrument). The convex part of the needle is positioned at 3 o'clock. (B). The instrument is rotated clockwise 90° so the convexity points toward 6 o'clock. (C). The right needle driver can grasp the needle, one‐third to half the distance from the swaged on end, and the place the suture bite. (D). The needle is well positioned for a right‐to‐left suture bite.
Needle Dance
Techniques for Knot Tying: Simple Interrupted Sutures
Similar to open surgery, many knot‐tying techniques are available in laparoscopic suturing. Here we will provide detailed instructions for two alternative techniques used in the VALS curriculum to successfully train a great number of novices.
Figure 2.16 Needle introduction through a right‐sided cannula according to Brody et al. [11](A). The needle is backloaded on the right‐hand instrument (i.e., with the needle tip pointing in toward the shaft of the instrument) and introduced with the convexity to the left at 9 o'clock. (B). Needle visible in the field at the 9 o'clock position. (C). The right instrument is rotated clockwise 90° so the needle convexity now points to 12 o'clock. (D). The left instrument
