Address of the Author:
Sabine Cécile Fischer
Section for Minimally Invasive Surgery
Centre for Medical Research
Waldhörnlestr. 22
72072 Tübingen
Phone: +49-7071-29-81248/81233
Fax: +49-7071-29-5569
e-mail: sabine.fischer@uni-tuebingen.de

There is a need for secure and easy methods for suturing in laparoscopic surgery, no matter whether vessels are to be ligated, two structures are to be safely sutured together or the cystic duct has to be occluded in cholecystectomy. Laparoscopic suturing can be done with a suture, using automatic sewing devices or clips. Unsafe ligation of a vessel for example results in the complication of bleeding, which is more difficult to treat in a laparoscopic than in an open procedure. When a surgeon wants to suture laparoscopically in the traditional way by using a Roeder knot for instance, the tieing of the knot requires some expertise and makes the procedure more complicated and time-consuming. Clips are used, because they can be applied quickly. Several articles^, show difficulties caused by the use of clips. Loose clips can cause stone formation in the common bile duct^,,.

An easily applicable alternative is needed with the safety of traditional sutures. A pretied knot for easy and quick application can fulfill this task: Quik StitchÒ by PARÉ Surgical, Inc. (Figure 1) is a new laparoscopic suturing device that helps the surgeon to use traditional suturing techniques. The applicator is loaded with a suture spool /Figure 2) that contains the pretied knot.

Quik StitchÒ was tested in several phantom and animal experiments. The experiments were performed with the suture spools Bondek and Polydek. Bondek is an absorbable suture, whereas Polydek is nonabsorbable. Figure 3 shows, how the suture spool is connected with the applicator and how the suture is made.

The experiments were used to test application and overall tightness of the sutures applied with Quik StitchÒ and perform the pull-off tests. We used pig and cow mesentery.

Vessels measuring 3 - 4 mm in diameter were double ligated with Quik StitchÒ and cut between the ligatures. Blue dye was injected with a syringe into the vessel near the ligature and we noted whether or not the color appeared on the cut end of the vessel.

The pull-off test (Figures 5+6) was then performed by pulling a loop that had been integrated in the ligature. As soon as the ligature started to move the force applied was noted using a load cell.

Additional phantom experiments were used to test the strength of sutures used for fundoplication.

The pig was under general anesthesia. The testing of the tightness of the sutures applied with Quik StitchÒ was performed with a specially designed pressure testing system (Figure 7). A vessel of the mesentery was cannulated. Distally of the cannula Quik Stitchâ was applied twice in neighbouring positions and the vessel cut in between (Figure 8). Via the cannula a steadily rising pressure was built up. It was recognized and noted in the protocol, at which pressure the ligature was not tight anymore. 350 mbar was chosen as the minimal requirement, because this pressure is higher than the normal arterial blood pressure of a patient.

Additional animal experiments were used to test the titanium clip from a leading manufacturer in the same way as Quik Stitchâ .

104 ligatures were made, 2 per vessel. 34 of these ligatures were used to optimize applicator and spools. 38 of 70 were applied in the phantom and 32 in the animal experiments. In the animal experiments only the ligatures near the cannula were pressure tested. The tightness of the ligatures on the other side of the cut was observed. Tightness means in this case no blood appeared.

Tightness of ligatures with Quik Stitch:

All ligatures were tight in the phantom experiments (38). In the animal experiments 15 of 16 ligatures resisted pressures of 350 mbar upto 900 mbar. Only 1 of 16 was untight at 250 mbar. No blood was observed on the opposite cut vessel end (16).

Pull-off Test of ligatures with Quik Stitch:

It took 4 - 9 N to loosen a ligature with Quik Stitchâ . The knot never opened.

Titanium Clips:

Of the 22 clips 11 clips slipped off before pulling (e.g. while attaching the loop). The other clips could easily be pulled off with the minutest force applied (between 0.2 and 1.7 N) (Figure 9).

8 clips were submitted to the pressure test. In two cases already at 100 mbar the clips were not tight anymore. The other 6 were tight between 450 and 700 mbar.

Fundoplication (Figures 10+11):

Two folds of a pig stomach were attached to each other by using Polydek. We performed 5 experiments in the phantom model. The folds were firmly connected with each other and pulling of the underlying loop could not reopen the knot or loosen the ligature.

For laparoscopic procedures special sewing devices, ligating instruments, knot pushers, clips and clip appliers have been developed. From the point of easy application clips seem to be ideal, but as literature shows there is a migration of clips^,,,, followed by stone formation in the common bile duct or even mechanical small-bowel obstruction. The loosening of clips means an increase of bleeders, if clips are used for the occlusion of vessels. The risky point of a clip is the open end of its u-shaped design, that makes it possible for the clip to slip off. Sutures avoid this risk by totally enclosing the structure to be occluded. Knotting instruments require a two forceps technique, while for sewing devices one working channel is enough. Automatic suturing devices tend to be disposable, so environmental requirements are not fulfilled at high costs. Knot pushers are reusable, but are reported to lose the thread when the knot is pushed down. Quik Stitchâ is a reusable device applicable through one working channel, that proved to be a secure method for the ligation of vessels of the mesentery and can be applied quickly. There is no way to reopen the knot after having tightened it, while the tightness of the ligature itself can be adjusted by pushing the knot down as far as requested. Proper application of the suture with Quik StitchÒ is the main condition for the safe occlusion of vessels. Therefore the training of the user in the correct use of Quik StitchÒ is a crucial point. For fundoplication the advantage of Quik StitchÒ is the possibility of adjusting the tightness of the knot stepwise, until the surgeon feels, that the suture is under correct tension. The correctness of the suture in fundoplication may be adapted to the demand in open surgery („loose and floppy") by using the Tübingen balloon, a balloon that indicates the extent of tightness of the ligature. All of the sutures with Quik StitchÒ stayed in place in contrast to the high percentage of clips that slipped off, therefore the use of Quik StitchÒ can be recommended for safe ligatures and sutures.