Endo-Laparoscopic Suturing and Knotting: Tips and Tricks

Abstract

During General Surgery training, suturing and knot-tying for open surgery is relatively easy and one of the initial skills to be acquired and mastered. In contrast, similar skills in Minimally Invasive Surgery (MIS) are more challenging to acquire and take an eternity to achieve proficiency. Competence and confidence in laparoscopic suturing allow the surgeon to venture into complex procedures and is an indispensable skill for dealing with intraoperative events.

Introduction

During General Surgery training, suturing and knot-tying for open surgery is relatively easy and one of the initial skills to be acquired and mastered. In contrast, similar skills in Minimally Invasive Surgery (MIS) are more challenging to acquire and take an eternity to achieve proficiency. Competence and confidence in laparoscopic suturing allow the surgeon to venture into complex procedures and is an indispensable skill for dealing with intraoperative events.

In open surgery, one has the advantage of binocular vision providing depth perception; however, in MIS, the surgeon encounters various hindrances: indirect visualization, loss of freedom of movement, fixed-port positions, and limited working space. These eliminate three-dimensional view (unless using a 3D video system), restriction of instrument movements and movement about the target, and restricted movement within the workspace. Ergonomics contributes to setting a comfortable and efficient posture for executing the skill; cognizance of elements like azimuth angle, elevation angle, manipulation angle, and triangulation are beneficial. Effect of stress, pressure, and fatigue during MIS procedures contribute to the adverse performance of fine movements in this skill. Thus, endo-laparoscopic suturing is associated with a longer and steeper learning curve compared to that in open surgery [1].

Aside from the knot-tying skill and the type of knot thrown, the braiding, the material, and the size of the suture used influence the security of the knot. The monofilament sutures have a risk of slippage and are less pliable compared to braided sutures. The hydrophilic material (catgut, Dacron, polyglactin, and lactomer) swells on contact with water and theoretically results in a more secure or tighter properly thrown knot. Among sutures of similar material, the larger sized will allow more force to be applied before breaking thus the tightness of a knot using 2–0 suture is double that of one with 3–0 suture.

As a teaching module, there are various options to choose from and Peyton’s four-step approach seems the most attractive. It can be used for a better teaching-learning experience. It includes:

• 1. Demonstration

• 2. Deconstruction

• 3. Comprehension

• 4. Performance

It is practice and repetition which helps acquire the skill and bring finesse to the application of the trained knowledge in the operating room [2]. Hospitals and medical universities need to modify their training curricula to include the basic and advanced suture training courses, skills lab, simulators, and personal video-box assembly and self-training along with regular conduction of outreach programs to further spread the basic skill, knowledge, and awareness.

Equipment and Instruments

• Laparoscope camera with monitor display and light source,

• Laparoscopic needle driver set,

• Laparoscopic grasper and forceps laparoscopic scissors,

• Knot pusher for extracorporeal suturing,

• Trocars–5, 10, 12 mm ports—metallic or plastic.

• Sutures.

• Mayo scissors.

• Artery forceps.

• Measuring tape.

There are different types of needle holders available. Generally, needle holders have jaws that are more powerful and sturdier than other laparoscopic forceps and graspers. They have serrations for better needle grip, a catch for locking and unlocking, and they can be straight or curved and fits in the 5 mm trocars.

General Principles

Setting the Scene. It is a crucial and important step in suturing. It should be like an orchestra and the surgeon needs to put himself in the best ergonomically available condition concerning position, angle, height, choice and placement of instrumentation, light source, choice of suture, and type of knotting among others. A good camera with adequate lighting and a high-definition display can make all the difference that is required for a smooth surgery.

The thickness of the abdominal wall, the position, and the angle of the port placement are vital. Too far or too near will make it difficult to maneuver. If the angle of the port is not in the same direction as the region of surgery then it will cause the surgeon to work against the abdominal wall, especially if it is an obese patient.

Position of the Surgeon. The camera should be positioned between the two instrument ports; this setup matches the normal relationship between the eyes and two hands as in open surgery (Fig. 1a). The surgeon should be in a relaxed stance with the table height matched adequately so that he/she does not have to slouch or strain. The monitor should also be placed at an eye level to prevent neck strain, this is especially important in lengthy surgeries and high-volume centers (Fig. 1b).

Fig. 1

(a) Camera position and (b) Surgeon’s stance

Eye-Hand Coordination. Movements made during laparoscopic surgery should be slow and steady compared to open surgery and the movements have to be limited to the field of vision. This is especially true when one is dealing with sutures and instruments like scissors and cautery. Eliminating unnecessary movements and taking choreographed actions during the procedure will help the surgeon and the OR team for more focused and productive output. A formal training course can help to learn these ergonomic skills for better productivity. A high level of concentration is integral to perform even simple needle-driving maneuvers.

Needle Tip and Suture Materials

Different types of needles:

• Straight needle,

• Ski needle, and

• curved needle.

The straight needle is easier to insert and remove from the trocars but is not used frequently. Also, the different angles to be achieved by the straight needle is difficult to achieve comparatively. Ski needles are easier to go through the trocars on the comparison. Straightening the curved needle using the needle drivers/forceps before removal is another tip for easy extraction.

A needle tip with taper cut penetrates tissues more readily than blunt tip needles hence lesser trauma. Needle size of 2–0 and 3–0 is optimal for laparoscopic use as it allows easy passage and removal in the trocars.

While using just the one 10 mm camera port with a combination of 5 mm ports during surgery, inserting a needle can be done through the 10 mm camera trocar and after suturing, it can be extracted through the 5 mm trocar after straightening the needle. Before inserting the suture, the direction of the 10 mm trocar should be static after confirming the visual field of the camera to a safe area so that even though it is a blind insertion of the needle, it will land safely in the operative field.

Colored sutures are preferred over colorless sutures for better visibility. Traditionally divided into two groups: absorbable and nonabsorbable; braided and monofilament. A suture that swells in contact with water increases its capacity of tying and tightening and can be considered safer, whereas monofilament sutures have a higher risk of slippage when compared to braided sutures. The tightness of a suture knot of a 2/0 thread is double than a 3/0 thread (Fig. 2).

Fig. 2

Types of knot

Insertion and Retrieval of the Needle. It should be done only under direct laparoscopic vision. The suture thread should be grasped some 2–3 cm behind the needle while transferring it in or out through the trocars.

While extracting the needle through metal trocars, there is a chance of the needle to get caught in the diaphragm of the trocar on its exit, which can then snap and/or break the needle. The diaphragm should be kept open manually while extracting the needle. Some may prefer to straighten the needle for easy extraction.

Loading the Needle: Loading depends upon the conditions and also the proximity or otherwise of a smooth serosal surface. There are two processes for loading the needle.

• The dangling pirouette technique.

• The deposit—pick-up technique.

This can be achieved in three ways:

• 1. First, the thread around 2–3 cm from the needle is held using the dominant hand. Next using the nondominant hand grasp the needle about one-third from the tip. Now the dominant hand is repositioned at two-third from the needle tip—the sweet spot.

• 2. Lightly grasp the needle at the distal one-third with the nondominant hand. With the dominant hand gently pull the thread—2–3 cm from the needle—towards you or away from you so that angle from the needle can be modified. Now with the dominant hand reposition the grip on the needle at the sweet spot.

• 3. After laying the suture on a safe surface, using the dominant handgrip the needle lightly at the sweet spot and gently brush with the concavity of the needle on the tissue forward for backward within the 3 o’clock direction till the correct position is attained. The nondominant hand can be used to assist as well.

Loading the needle during laparoscopy is an important skill to master. It should be learned by all surgeons who are interested in pursuing the minimally invasive approach. Suturing and needle handling are crucial. A trainee has to understand and learn how the needle driver works laparoscopically and how to move the needle and the needle drivers effectively through the tissues without causing unnecessary trauma.

The ideal length of a suture for intracorporeal suturing is 10 cm; this length makes the knot-tying maneuver easier. For a continuous suture, the thread should be about 15 cm long, this allows the surgeon a way to accomplish the final knot with enough suture thread in hand.

Techniques of Knot Tying

In the intracorporeal technique, the knot is made inside the abdominal cavity using two instruments, these can be two needle holders or forceps.

In the extracorporeal technique, the knot is made completely outside the abdominal cavity and then it is pushed inside the abdomen with a knot pusher.

Intracorporeal Knot Tying

The advantage of intracorporeal suturing [3] are:

• The amount of suture that is being drawn through the tissue is limited thus reducing trauma and cut through, and,

• The suture material that is being used can be finer.

Hence, delicate structures like bile ducts and intestines can be sutured using this technique.

Before throwing the knots, it should be checked that the distal end of the suture is no longer than 2–3 cm and in vision so it can be grasped easily. The number of throws depends on the suture used.

Roser Technique

Hold the needle with its concavity bent downwards with the nondominant hand. In this way, the curved and rigid structure of the needle allows the forming of the “C-loop” for the needle holder of the dominant hand to twirl on it. This makes it easy to perform the spirals around the needle holder before grasping the distal end of the suture.

To complete the knot, the needle is dropped in a safe place and the nondominant hand grasps the thread close to the knot to tighten it by moving the hands in opposite directions. Repositioning of the instruments to hold the suture closer to the knot should be done to stay within the visual field to avoid injury to adjacent structures.

The first knot placed is a double spiral/throw. This is followed by again holding the needle with concavity down and repeating the above process to throw single knots and tightening it.

Szabo Technique

The C-loop can also be made with the suture instead of the needle concavity around which the twirls can be made for the knots. The C-loop can be made by just pulling the suture slightly forward or outward with the dominant hand while the distal end is being held by the dominant hand before throwing the spirals.

Alternative Method

Grasping the suture thread 1/2 cm distal to the needle with the dominant hand, then one has just to rotate the instrument to wind the thread around the needle holder. Then forceps are used to grasp the needle end with the other hand while the dominant hand catches the distal end of the suture. The knot is accomplished by pulling on both ends.

Suture Designs

A thread furnished with absorbable terminal clips for anchoring. The clip anchored to the suture thread end functions as an initial knot and a second clip can be applied at the proximal end after suturing is complete to avoid the need for tying knots.

Another is barbed sutures which prevent it from slipping back through the tissues and avoids the need to make knots to secure it in place.

When using a braided thread, a preformed loop can be created simply by piercing the distal end of the suture with the needle, exactly at its middle. Then the needle is pulled through this newly formed loop, to stabilize the suture and continue for continuous suturing.

Or a preformed loop can be made for this purpose (described below).

Extracorporeal Knot Tying

It is important to learn at least one knotting technique and use it when required. The advantage of extracorporeal suturing is the ability to use familiar knotting as in open surgeries which can then be secured using a knot pusher. However, it is not preferred for suturing delicate structures. Extracorporeal slip knots can only be used for free-ending structures, like the appendix, peritoneal tear in TEP, and for ligating transected duct/vessel.

It is of two types:

• 1. Extracorporeal slip knot

• 2. Extracorporeal surgeon’s knot

There are a lot of methods to make a preformed loop for a slip knot, here a couple of them are described. The length of the suture has to be 45 cm for the creation of the loop for the slip knot.

• Tayside knot: Perform 3–4 windings between the distal and the medial end of the suture, this results in a loop through which the distal suture end is threaded. This generates a new loop through which the distal end of the suture is passed. By pulling on the distal suture end the knot is tightened generating a slipknot.

• The formula for making the Roeder’s knot is (1:3:1) “one hitch, three winds, and one locking hitch”. First, a loop is made around a post and then a simple knot is made. With the shorter end, three winds are made around both posts and are secured with the last half hitch. The knot is then tightened and checked for sliding. The excess length of the string is trimmed.

• Also, there are commercially available Endoloops which can be used, but with added cost.

Once this preformed loop/Endoloop is inside the abdominal cavity, the structure to be ligated is placed through the loop and the loop is tightened with the knot pusher, and the excess suture cut.

For structures which are not blind-ended (e.g., vessels or cystic duct) the following methods can be used.

• A suture thread is passed under the structure and both ends are taken out. A loop as described above is tied and is then pushed down with knot pusher and tightened.

• Also instead an extracorporeal surgeon’s knot can be made and pushed in followed by square knots to secure. This can be used in all instances of laparoscopic suturing however due to the long length of suture chances of cut through and inadvertent injury is higher. For extracorporeal suturing, the suture length has to be at least 75 cm (Fig. 3).

• The granny knot and square knot can be converted into a slip knot by applying tension on the suture ends as demonstrated. And then this can be slipped down using graspers/knot pusher to tighten the knot. This is easier when using monofilament sutures.

Fig. 3

Slip and square knot

There are other options available for stitching apart from the sutures. They are:

• Liga clips and Hemolok clips: They can be used for clipping small and medium-sized vessels/ducts and replaces the need to place sutures and saves time.

• However, they require specific instruments for their deployment.

• Tackers: They are absorbable or nonabsorbable. They are used to fix the mesh in situ and for the closure of the peritoneum.

• But since they are driven into tissues they are associated with some pain postoperatively, can lead to bleeding if it punctures vessels and if used in the path of the nerves then chronic pain.

• Hence should be used with good anatomical knowledge.

• Stapling devices: They can also be used laparoscopically with good outcomes. They can be used for gastrointestinal resection/anastomosis and bile duct resection. Stapling devices borrow the same principle as used in open surgery, but are technically more demanding, with the limited space available and different angles to fire the staples at. They are available as straight and circular devices for anastomotic purposes. The circular device is more complex to use. It is used for endo-laparoscopic anastomosis of the esophagus, rectum, and gastric cuff in bypass surgery. For intra-abdominal insertion of laparoscopic stapling devices, a 12 mm port is required.

• Tissue Glue: Tissue adhesives are also being used in certain conditions like for fixation of hernia mesh in TEP and TAPP. The advantage being that it does not cause chronic pain and can be used on and near the triangle of pain for better fixation when compared to tackers. It is also being used in combination with other techniques as an aid that provides a hemostatic or hydrostatic seal.

Conclusion

Practice and repetition are required to master any skill in surgery and especially in laparoscopy and laparoscopic suturing and knotting.

Performing a suture and a knot in laparoscopy without the necessary experience and practice not only increases the operative time but it also indirectly increases the hospital costs by increasing the consumption of medical supplies, increasing morbidity, increasing the patient recovery period, length of stay, and more importantly decreasing the surgeons productive and functional output during the operation. To improve on this, a trainee can record and analyze their techniques from simulators/skills lab and obtain feedback from colleagues and experienced trainers to perfect them.

Despite modern technology, a laparoscopic surgeon still needs to learn and perform the traditional suturing and knotting techniques as one may never know when and where it will be required and essential. Skills lab and training courses are important for such teaching-learning programs and should be made essential for all teaching institutes as a part of their curricula.