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Practicals

General background - training for laparoscopic surgery

Different from traditional open surgery, specific problems that are related to video-visual perception and psychomotor skills must be identified and overcome. Many of the required skills are not used in conventional open surgery. The early recognition that the rate of complications correlates with the number of procedures done by the surgeon has highlighted the need for formal training in laparoscopic surgery. No consensus has been reached, however, on what constitutes adequate training. This chapter discusses general training methods and goals.
Training in laparoscopic surgery includes didactic instruction, virtual reality exercises, in vitro training in simulators, and operating on animals and patients. Each kind of training has its merits and limitations, which must be considered when embarking on a training program. Also, in some centers, the approach to training for surgical residents who need an overview of laparoscopic procedures and techniques differs slightly from training for experienced surgeons wishing to develop a specific laparoscopic practice.
Some evidence indicates that it may not be necessary for specialized surgeons to learn how to perform basic procedures (e.g., the laparoscopic cholecystectomy) before learning how to perform a more advanced procedure. It has been shown that the ability to perform a laparoscopic cholecystectomy does not confer the level of skill for more advanced procedures, such as the colon resection and also that colon resection can be taught without prior experience of laparoscopic cholecystectomy.
Although specialized surgeons can be taught to perform advanced procedures without experience of the more basic ones, there is a concern that the complication rates (shown to be related to the total number of procedures done will be higher for these surgeons when compared with surgeons with a greater experience of laparoscopic surgery. It is recommended that all surgeons be trained in simpler laparoscopic procedures before performing more difficult ones.

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Didactic instruction

Didactic instruction occurs in various settings: during training courses, postgraduate courses, and meetings of surgical societies. The two components are general instruction and specific procedural training.
The general component should cover familiarization with the instruments, especially the principles of using and troubleshooting the imaging system; principles of operative techniques, especially trocar placement; exposure of the operating field; and principles of intracorporeal suturing. This instruction is necessary before specific procedures are attempted, especially procedures requiring the use of two hands and intracorporeal suturing. Training surgical residents to perform specific procedures should include a brief explanation of the key steps of the procedure and showing video clips.
The key steps in the procedure should be pointed out while the proper instruments are discussed (e.g., electrosurgery, dissectors, and graspers). Videotapes should be available for students to review at their convenience. The major complications and their avoidance should be covered. Videotapes of complications or "near complications" have a great impact.

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In vitro training

The first step is practice in a trainer box with ports for instruments and the scope. Many trainers are commercially available, ranging in design from plastic boxes with holes for trocar placement to those with a small video camera built in, so that they may be connected directly to a TV monitor without having to borrow a camera and light source from the operating room.

Trainer box and instruments

One should practice on the same quality optical-video-monitor setup as used in the operating room. This creates a true and correct eye-hand coordination. In vitro training can be a valuable precursor to operating in live animals and humans in several areas. First, it is useful for establishing the mental framework and steps of the procedures difficult parts. Fresh animal tissue can create surprisingly lifelike models. Team interaction between surgeon, camera operator, and assistant can be practiced, the best time to learn how to use the camera.

Fresh animal tissue model. The pelvi-trainer is ideal practice equipment

This setup is well suited for intra corporeal suturing skills and live animal practice to teach operative surgery. Most of the students can acquire the idea of placing a suture and tying a knot in about 2-4 hours. Progress beyond that varies between surgeons, and influenced by the frequency of practice. An experienced/professional instructor should do the teaching because many steps (e.g., mounting the needle in the needle holder, laying out the suture, and best use of the camera) are not intuitive and differ from those in open surgery.

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Teaching by example

The exercises and their steps are either shown on video clips or in person by the instructor. The personal tutorial is the most effective and stimulating teaching, challenging the students to imitate the instructor which is the most efficient teaching method. Goals during the suturing should be to complete the prescribed, personally demonstrated knots within the standard times.

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Use of animals for training

If live animals are not available for training, dissecting technique and simulated operations could be performed on fresh slaughterhouse organs in an in vitro trainer. However, operating on live pigs (female Vietnamese; average weight up to 30 kg) is extremely useful for developing skills, trying out new procedures, and gaining experience with new and unfamiliar instruments. Approval must be obtained from the institution’s animal use committee.
In general, the pig is a good model for acquiring skills such as trocar placement, exposure, and the appropriate use of gravity, traction, and countertraction. Other important skills, such as two-handed dissection, intracorporeal suturing, use of mechanical stapling and anastomosis devices, and dealing with complications such as bleeding and bowel perforation can also be learned. Perhaps not surprising, the most frequent cause of animal deaths is hemorrhage.

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Training for specific procedures in the pig
The pig is a good model for the surgeon to practice dissecting the gallbladder from the liver bed during cholecystectomy, but no animal really mimics the anatomy of Calot’s triangle enough to be a good model for the human operation. This limitation has to be borne in mind when transferring experience gained in pigs to humans, because the most serious technical complications of cholecystectomy occur from mistakes during the dissection of Calot’s triangle Furthermore, the cystic duct of the pig is too small for transcystic common bile duct exploration. Anatomic differences also make the pig a poor model for appendectomy, right hemicolectomy, and hysterectomy.

Porcine model

The pig is an excellent model for operations on the upper gastrointestinal tract for antireflux procedures, vagotomy, Heller cardiomyotomy, pyloroplasty, gastrectomy, gastrostomy, jejunostomy, cholecystojejunostomy, and gastrojejunostomy. Experience in these operations in pigs is relevant to the same operations in humans.
The pig is also a good model for laparoscopic assisted anterior resection of the colon, although the absence of fat in the mesentery makes the mesenteric dissection easier in pigs than in humans.
The pig is also a reasonable model for laparoscopic transperitoneal hernia repair. The anatomy is not too dissimilar; the main difference is that the pig has two inferior epigastric arteries. The procedure itself can be easily performed in pigs. Preperitoneal hernia repairs and other preperitoneal procedures are more difficult to simulate in pigs because their peritoneum is thinner than in humans. Therefore, it has a tendency to tear, which leads to loss of the pneumopreperitoneum.
Splenectomy may be performed in pigs, but the pig spleen has a different shape and is more mobile than the human spleen.

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Limitations of training in the animal laboratory
Three students per pig, with students rotating as surgeon, camera operator, and assistant, is a good arrangement at the start. It is ideal if the three students come from the same institution and plan to operate as a team after completing the course. One instructor is assigned to each group of three students. Over the period of the course, the students should be exposed to different instructors and thus to different operating styles and techniques.
The major limitation of animal training courses is that students cannot really gain enough experience to perform the more difficult operations, such as fundoplication, on humans. Even after a five-days course on several procedure (laparoscopic cholecystectomy, appendectomy, hernioplasty), some students remain unable to complete the procedure satisfactorily as judged by supervisors. No data are available to indicate how much experience is truly required to bring performance to an acceptable threshold. In an experimental model, we have found considerable variation in the surgical skills of individual laparoscopic surgeons. There is a growing belief that permanent training facilities are needed where surgeons can train regularly until they reach a point where they are fully prepared to perform technically difficult procedures in humans. A better understanding of the nature of surgical skills and how to measure them is also needed.

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The role of technology in training
New technology perhaps promises to improve the effectiveness of training programs and the capabilities of surgeons in the operating room. For example, virtual reality trainers may facilitate the objective assessment and initial training of laparoscopic surgeons but will not replace animal models.

Traditional laparoscopy and robotic practice

Manufacturers are attempting to produce devices (most of which are still experimental) that simplify more difficult tasks, such as suturing and knotting. If successful, this should allow more surgeons with reduced skill to perform advanced laparoscopic procedures. Although after much investment there is still no satisfactory and cost effective substitute is found.

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Suturing, tying knots

Principles

Traditionally surgeons are in a hurry. The handicap of laparoscopic approach and suturing/knotting generates a great deal of frustration and fumbling, particularly in the novice. As tissues are magnified and instruments moved, it is very difficult to visually trace the trajectory of the two instrument tips, particularly when these movements are fast and erratic. Even for experienced surgeons movements must be slowed down in order to regain control and restore precision. Magnification and reduction of the operative field size require a proportionate reduction of movement speed and range (path) in order to regain eye-hand coordination and overall control. The use of long-stemmed instruments with distant fulcrums adds to the challenge.  The best remedy to any situation that is "out of control" is to slow down in proportion to the degree of magnification and to focus one's attention exclusively on the task at hand. The greater the magnification and/or the more difficult the port position setup, the more one must slow down when suturing tissue edges together or tying an intracorporeal knot. Slowed movements not only permit recognition of impending error and appropriate correction of action, it also provides good control.  This, in turn, builds confidence.

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Challenges and solutions

The challenge of intracorporeal suturing and knotting centers around four areas: 1. visual perception, 2. eye-hand coordination or psychomotor skill, 3. setup, and 4. the mental framework.

Visual perception
The surgeon's normal visual perception is altered by viewing the operative field through a closed-circuit video system which is based on the 70°-90° angle optical view of the most common laparoscopes, a poor comparison to the unaided conventional overhead view or even to the brilliant 3D image seen trough the surgical microscope.

Magnification

A flat, two-dimensional image requires strategies and visual memory to overcome the lack of depth perception; currently available 3-D systems make little impact on improving the surgeon’s performance. More important is using a system that can provide a high degree of visual clarity, sharpness and illumination. The surgeon would be best served by making certain that an optimal image is preserved throughout the procedure.

Good quality image

This includes: 1. tuning the video system to its optimal level, including correct color rendition and contrast; 2. maintaining sharp focus; 3. centering the action on the monitor, 4. keeping the optical components clean, 5. wearing recently checked corrective lenses if needed. These factors are of great significance although they are often neglected. With substantial practice and experience, visual memory develops; the image becomes more informative to the surgeon, especially with regard to the different spatial relationships, references points, and the altered view of anatomy.

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Eye-hand coordination
This challenge greatly depends on the magnification. Optical magnification is determined by the laparoscope and additional modification by the video display. The final magnification is controlled by 1. the distance from the scope objective lens to the target tissue; 2. the setting of the zoom lens (ring) on the coupler between the ocular and the CCD chip, and 3. partly on the length of laparoscopic instruments and their relative pivot points.

The instrument length and its pivot point are significant in influencing the excursion if the surgeons hand and the tip. The longer the instrument the further is the pivot point and causing uncertainty of the instrument tip movement which is critical. Although with practice the particulars of movements become automatic, muscle memory develops. The practiced laparoscopist concentrates on the visual clues on the displays and although initially aware of the hand movement, soon transcends it. Focused mental concentration takes over and will based on visual clues will direct the surgical movements. The physiology of skilled task performance is complex but studying it helps to understand the teaching and learning of it.

Visual tracking is an important skill component as well as the controlled versus ballistic movements. As the surgeon makes a small random hand movement (action) causing the instrument tip to move (reaction), visually tracking it, assessing its position and making an other action movement adjusting the path of instrument tip reaction. This is like trial and error process and after some practice one gets a feel for the correct hand movements resulting in the desired tip trajectory, in other words one mostly transcends the human hand/instrument interface, the direction and amplitude of action movements. Solutions: 1. coaxial line up, 2. triad port positions, and 3. ideal directions.

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Coaxial alignment
Coaxial alignment refers to the following five components being arranged along a straight line:
(1)   The position of the surgeon,
(2)   The viewing port (laparoscope and camera),
(3)   The instrument ports,
(4)   Target tissue,
(5)   Video monitor.

Intuitive and translating setups

This arrangement provides optimal access to the operative site, and reduces the stress on the human brain when calculating and translating the relationships of instrument movements and target tissues. This is the everyday used setup of common tasks, intuitive and the eye-hand coordination is familiar.
Ideally, the video system should include a high resolution 19-inch monitor and be viewed no further than 5-6 feet away. The laparoscope and instrument ports need to be placed in a fashion that duplicates the natural anatomy of the surgeon; that is, placing the camera in the middle and the suturing ports on either side in advance of the surgeon's frontal plane, just like the human eyes are in the middle and the hands on either side. The distance between the suturing ports should be approximately 20 cm or so. Having the ports closer or further apart would still enable the surgeon to suture; however, it would be significantly more difficult.

Use of a laparoscope holder, whether mechanical, pneumatic, passive, active or robotic, is desirable, preferably with a zooming device for difficult suturing situations. It will provide a rock solid, steady image that a surgical assistant would be hard pressed to duplicate over a prolonged period of time. Also it will permit the solo surgeon to practice a two handed technique.  The zooming device would allow magnification changes, i.e., a close up or panoramic view, as required for particular needs.

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Triad port positions
Suturing essentially requires three ports, one for viewing, and one each for the right and left-hand instruments. The most intuitive arrangements of these ports consists of the view port being in between the right and the left instrument ports in a triangular formation, duplicating the human anatomy (i.e., vision or the eyes in the middle, parallel with the axis of the coaxial line up). When attempting to suture in a different location, these three ports can be shifted in unison to the new position. Most target tissues can be approached from the base position of putting the laparoscope in the umbilicus and having an assistant position the tissue to be sutured in a favorable location.

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Ideal directions
The ideal directions for suturing in a magnified surgical field, again follows pre-established routines from ordinary activities. For the right handed surgeon the suture line should be in the 11 o'clock to 5 o'clock position and the stitches placed in the 2 o'clock to 8 o'clock direction.  Paper positioned at this angle facilitates writing in a straight line, parallel to the top and bottom edges of the paper (or perpendicular to the left and right edges). In a similar manner, this suture line should be positioned in the same angle, so that the stitches would be perpendicular to it. For the left-hander, the suture line should be positioned at a 1 o'clock to 7 o'clock position and the stitches placed in the 10 o'clock to 4 o'clock direction. Positioning tissues in this manner, as with any aspect of good setup, facilitates proper techniques and favorable results.

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Instrument handling

Instrument rotation
Laparoscopic suturing requires frequent instrument rotation such as the scooping motion of needle driving and rotating sutures during knot tying. Instruments with the traditional pistol or angled ring grip are unsuitable for these techniques since rotation is particularly difficult and awkward. While a highly skilled surgeon could use such instruments, it is an unnecessary burden that leads more quickly to surgeon fatigue.

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Instrument position
The importance of port positioning is not only in providing the proper angle of access but also a fulcrum for the instruments that is exactly halfway between the tip and the handle. That is, 50% of the instrument shaft is inside the body cavity and 50% is outside. This provides a 1:1 ratio of movement between the handle and tip

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Choreography of movements
Although slowing down restores the necessary control and movement precision, it also increases operating time. This increase will be in proportion to the magnification and the complexity of the setup. Certain components of suturing technique involve repetitious movements such as needle driving and knot tying. These movements can be analyzed, broken down to their most basic components, then reassembled into the most efficient and intuitive process ("choreography"). Every movement made should flow into the next ("fluency"). This fluent choreography, coupled with a reduction in movement speed, enables precision controlled movements and a reduction of operating time. When this choreography is memorized, it benefits the surgeon when learning a new procedure. It arms him or her with a technique that is standardized and frees the surgeon to focus on the variable aspects of the procedure. In doing so, the surgeon can easily recall and be duplicate the sequence of steps even under stress.

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Economy of motion
A complimentary component of movement choreography is the economy of motion, which will further shorten operating time. Nervous, random, and uncertain movements need to be eliminated and replaced with deliberate, purposeful maneuvers. Simply by eliminating the need to correct small mistakes, such as re-grasping tissue that is let out of the jaws of an instrument, considerable time will be saved. These movements must be planned in the surgeon's mind and slowly executed following a mental image, keeping the action as close as possible to the ideal. Considerable time and effort is required to develop a smooth choreography, flawless technique and maximum economy of motion but the reward is commensurate. An individual style can be developed that is effective, efficient, and elegant. One of the best demonstrations of the economy of motion is during the very beginning of suturing is loading the needle.

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Ambidextrous technique
When suturing in a handicapped surgical setup such as the laparoscopic field, the surgeon really cannot afford to be dominantly single-handed. Even with the most careful preplanning and placement of instrument ports, a situation can easily arise that favors using the non-dominant, (e.g., left-handed) for needle driving and knot tying. While the tissues might be adjusted to a more favorable position for right-handed execution, or the surgeon could persist with an awkward right-handed move can be made, this is likely to cause tissue damage. Further, a less-than-ideal stitch placement, and/or an awkward looking style may result. To get maximum potential from laparoscopic surgery, the surgeon is advised to develop ambidextrous suturing and operative technique.

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Touch confirmation
In laparoscopic suturing the spatial location of various objects, the suture, and tissues in the field are often difficult to judge when relying solely on visual information from a 2-D image. A simple technique can be employed to enhance movement accuracy. This consists of touching the targeted structure lightly (gentle probing) to verify one’s estimation of the actual location. By practicing the "touch confirmation" technique the surgeon can gain critical clues to an object's true whereabouts before expending the effort to grasp it. In the process, actual spatial relationships become apparent and should be incorporated in the surgeon's visual memory.
With this information, the surgeon is able to transform a 2-D image into a "virtual 3-D" image. Touch confirmation is only one component of "virtual 3-D"; it also involves experienced visual perception as well as logical reasoning. The touch confirmation technique can result in movements that are remarkably accurate when coupled with the principles of slowed movements, sequential choreography, flawless technique, and the economy of motion.

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Sutures in practice

The goal of the courses is to impart the method of adapting the traditional open techniques to laparoscopic setting. However, this transition is not straightforward but can be started by a didactic lecture explaining some of the differences and important technical details. A brief description of the equipment and instruments used during the training sessions should be provided and the use of new or modified instruments also demonstrated. Training should begin with exercises in a simulator (suturing trainer box) using inanimate material. This provides an opportunity to become familiar with the equipment, instrumentation, and the particulars of intracorporeal suturing and knot tying. This can be as simple as transporting beads from one container to another or threading needles trough fixed eyelets.

Suturing exercises begin with suturing a latex glove that have two rows of dots marked and a cut made through it facilitates the skill acquisition of needle handling, precision entrance-exit bites, suturing, and the knot tying sequence. It is particularly important that good technique, such as targeting entrance and exit points, be practiced early on in training to avoid the development of bad habits. This is a physically and mentally stressful event, therefore it is recommended to be well rested and avoid caffeine before.
The techniques presented during the didactic session and each exercise should be personally demonstrated by the lecturer to course participants. Ideally, two residents per trainer setup allow adequate practice time. First, one surgeon assumes the suturing role while the other provides camera holding and assistance with positioning the target materials, etc. Each participant should work for approximately 3-5 minutes to accomplish a specific task, and then rotate roles. An experienced instructor should be readily on hand to provide guidance if any questions or difficulty arise.

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Exercises
In this initial phase it is important to discuss and practice the vital setup principles as well as to develop an appreciation for the economy of motion principle, choreographed movements, and flawless technique involved with suturing and knotting techniques. It is also necessary to approach these exercises with relaxed muscles, slowed movements, and tightly focused attention. Further, one needs to recognize that this is a form of precision technique where finesse triumphs over brute force.

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Suture length
The proper length of suture should be carefully considered and calculated prior to its introduction into the operative field. Generally, the length of suture to be inserted into the field should be the minimum length necessary to accomplish the suturing task (usually no more than 7-8 inches). First, introducing a suture longer than this would result in thread tangling and thus require its excessive handling.  Repeated manipulations and struggles with a long suture can be quite time-consuming and frustrating. Second, by inserting ideal length of suture necessary to accomplish the suturing task, eliminates the need for repeated process of removing of the used needle and introducing of a new one. By reducing the suture passage traffic through the ports, the likelihood of losing the needle in the port or field is reduced. Loosing a needle is reason for major concern. Third, a complimentary component of this concept involves where to tie the knot at the thread – it should always be positioned at the most distal portion of the thread. This is a basic principle in magnified surgery (e.g. microsurgery) and would be necessary to practice laparoscopically. On the other hand, by following the habit of open surgery of tying the knot conveniently in the middle of the thread, the result will be the need to use several sutures for a given task. Consequentially, the problems associated with heavy traffic of suture passage through the ports (potential needle loss) as well as unnecessary time consumption are significant factors. Furthermore, the suture line should be kept clear of suture tails and those not used as stay sutures should be snipped reasonably close (3-4 mm) to the knot to minimize visual clutter and maintain a clean and orderly surgical field.

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Needle loading and driving
The needles selected may depend on the size of the ports in use. A 5-mm port can accommodate straight and ski needles but a 10-12 mm port may be required for strongly curved needles such as the ½ circle. Care should be taken not to damage the needle tip during the transit trough the port.

To introduce the suture, the thread should be grasped with the assisting instrument 3-4 cm from the end of the needle. By continuing to hold the thread at this point, the needle can be dangled above the tissue surface and slowly lowered so that the tip of the needle touches the tissue. If necessary to adjust the direction in which the needle is pointing, the assisting grasper can be rotated in a manner to make the needle point in the proper direction for suturing.

The needle driver can carefully grasp the needle at 2/3 of length, at the rear and the surgeon can make small adjustments as needed. If the needle is grasped properly but is pointing in the wrong direction, its tip can be lightly hooked into the tissues. By pushing in one direction or another, it can then be pivoted into the proper position and held by the grasper. The appropriate grasping point on the needle shaft is approximately 2/3 of its length from the tip of the needle for a 3/8 circle needle, and roughly 1/2 way back for a half circle needle. The tip of the curved needle driver should be pointing towards the back end of the needle. Other words: spoon up. Holding the needle perpendicular to its plane by the needle driver provides the most effective grasp to penetrate into tissues. The needle should be driven in a course that is perpendicular to the suture line, by following its curvature to reduce leverage and tissue trauma at these entrance and exit points.
One should be pushing the needle against tissue resistance. It is done by initially driving the needle gently and watching for needle deflection. If the needle deflects to either side, making a small correction toward the other, the head on resistance direction will become obvious. In doing so, minimal tissue resistance will be encountered and needle driving will be a straightforward procedure. Slow movements enhance a smooth process.

Deviations from this seeking the resistance approach leads to a variety of difficulties, frustrations, and wasted time. To correct needle deflection (when the needle flips out of the proper position), the thread can be gently grasped about 1 cm behind the needle end and pulled in a direction to restore the proper position or simply the needle is pushed, pulled to make the needed correction. The surgeon's grip on the needle driver must be loosened somewhat to allow this adjustment, but not excessively or the needle will be dropped altogether.

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Suture lines
The appropriate suture line for a given repair can be determined by assessing the type and length of the defect, type of tissues involved, and their function. The continuous suture line can be completed more rapidly because it involves far fewer knots but it is more difficult to accomplish with the same level of precision than can be obtained with an interrupted suture line. It is prone to purses stringing and gaps.
Identification of the tissue edges is necessary, as is careful adjustment of the tension on each suture. One method is the use the assisting grasper to lift the suture tail, which provides some degree of countertraction during needle placement.

Continuous and interrupted suture

By using the tail of the first stitch to elevate the tissue, with the thread exteriorized and anchored with a hemostat on the surface of the skin, moderate tension is applied to the suture line and the tissues and suture line can be positioned favorably for completion of the repair. Another method is to have the assistant elevate the most recent stitch, or to lock the suture line every few stitches. In the end if any gaps or loose stitches are found, an interrupted stitch can be placed. An interrupted suture line is more conducive to a precise repair and in some cases such as a hand-sewn gastrojejunostomy, use of both types of suture lines is recommended at different aspects of the repair. Structures with lumen repaired with interrupted suture line to prevent stenosis.

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Intracorporeal knotting

Square/slip knot - convertible locking slip knot

The role of a stitch is to approximate tissue edges. This approximation is usually held by a secure, non slipping knot. On the other hand, it is sometimes desirable for the knot to be tied temporarily in non-locking fashion and moved later to its final position and securely locked. For example, in certain microanastomoses, especially difficult ones where free access is not possible, it might be desirable to place the primary stitches without initially approximating the cut surfaces. This allows the surgeon an opportunity to inspect the stitches for errors and when satisfied, then approximate the tissue edges and secures the stitches using the same knot. Another knot can be placed for additional security, if desired.
Another application of the convertible slip knot is for use in stay sutures. With the convertible slip knot, i.e. one that converts interchangeably between a locking and slipping configuration, considerable time and effort could be saved, a fact that might prove critical to microsurgical and endoscopic surgery applications.
The method of tying is similar to the standard square knot using the instrument tying method, with one exception. In this method the principle of avoiding instrument crossover during knot tying is applied. The disadvantage is that this requires more handling; the advantage is a safer, more controllable knotting.
This knot's unique feature is that it is convertible to a slipping configuration and re-convertible to a locking configuration. The square knot used here must be tied precisely as described in the following section, for if it is performed in a random fashion, random results will be obtained, ie. the knot will not work. Further, this technique must be mastered so that the procedure is executed efficiently and flawlessly to maximize on the time and effort saving benefits. It is this aspect that is crucial to the ease and success of performing microanastomoses and endoscopic suturing and anastomoses. The method described is for execution by a right-handed surgeon. Naturally, the steps can be reversed for left-handed performance. In fact, it is the author's opinion that ambidexterity is a highly desirable ability. The knot tying procedure is divided into two parts: (1) tying the square knot (composed of two opposing flat knots) and (2) converting it to its slipping configuration, relocating the knot, and reconverting it to its locking configuration.

The first flat knot

After the needle has made its exit and the thread is pulled through, leaving a short tail, the needle is placed somewhere in or out of the field in a secure location. The long tail is on the left side and the short tail is on the right side.

The needle holder (NH) (right hand) crosses over to the left side of the field and grasps the long tail. It is then brought over to the right side of the field, opposite the short tail and below it. The two tails combine to form a "C" configuration. (If tying with monofilament suture material, the NH should rotate counterclockwise so that the e loop is laid horizontally).

Continuous and interrupted suture

Starting position		First wrap

While holding the long tail with the NH (right hand), the assisting forceps/grasper (AG) (left hand) is placed over the suture and the long tail is wrapped once over then under the AG (NB: there should be a 3:1 ratio or greater between the length of the long tail and the short tail.)

The AG (left hand) reaches over to the right side to grasp the short tail and then the two instruments pull in opposite directions, the AG to the left and the NH to the right, tying parallel with the entrance-exit points of the stitch. It is best to move both instruments toward the short tail rather having the NH "choke" the AG as it reaches for the short tail

The NH (right hand) should maintain its grasp of the long tail but the (left hand) now drops the short tail. The NH (right hand) still grasping the long tail, brings it over to the left side and hands it over the AF (left hand).

Second (opposing) flat knot

 The (left hand) holds the long tail opposite the short tail (and below it), creating a "reversed C" configuration. Mirror image of the staring position. The NH (right hand) is placed over the reversed C and the thread is wrapped once over then under the instrument.

The NH (right hand) reaches to the left side and grasps the short tail (again, move both instruments together toward the short tail). The instruments move in opposite directions pulling the short tail through the loop, NH to the right and the AF to the left, parallel with the stitch. (It is important that the instruments not cross each other because that would obscure the field and errors could go undetected.)
The result should be and certainly is a square knot.

The converted form of the square knot. The pulled suture leg becomes straight providing a "guide wire" on which the pretzel-shaped double loop can easily slide. The slipping configuration permits pushing the knot tighter.

After the knot is satisfactory the slipping form needs to be reconverted to a locking form. To ensure secure, locking knot an additional flat knot is placed on top.

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Surgeon's knot

Double through with closing single twist

If modest tension exists at the tissue edges to be approximated the first single throw easily unravels, therefore a double throw would be more secure. The surgeon's knot is secured with a single throw in the opposite direction. The disadvantage is that this becomes a permanent knot, which cannot be adjusted. One might be convinced that after placing a surgeon's knot the tissue is properly approximated, only to discover later that the stitch is loose. As with all permanent knots, if adjustments are needed, the surgeon's knot has to be cut out and replaced. Considering the labor intensiveness of suturing and knotting, the square-slip knot holds a clear advantage.

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Granny knot

This is similar to a square knot and is made by combining an overhand throw with an other overhand throw. In other words the instruments do not change grip on the suture between the first and second flat knot. This is an unpredictable knot -sometimes it will slip and other times it will jam. It is usually the result of an incorrectly tied square knot.

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Twist knot

This knot was promoted because it avoids the complex choreography required by the square knot and could be tied with less developed skill. Using the needle holder the long tail is grasped and rotated 3 or more times around its axis, then the short tail is pulled through the loops created, pulled tight, forming a knot. Considerable effort is required to accomplish it correctly.

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Lasso knot

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Slipping loop

To create this knot, the end of the suture must be doubled or tripled and pulling the end trough the wrap, tied approximately 3-5 mm from the end, creating a loop. After the needle is driven through the tissues it is brought back and passed through this loop.  The tissues are approximated as the thread is pulled through the loop. The slip knot version can be tightened to hold and the permanent version will stay loose and is preferred for use in a continuous suture line.

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Prelooped suture

Similar to a lasso knot, this is a commercially available product that includes the pre-looped suture and a plastic applicator/knot pusher. The pre-looped suture introduced to the surgical field through a port. The tissues are pulled together and secured by the tip of the applicator. Then the thread is held taut and the applicator handle is pushed, tightening the loop and creating the knot. The threads are then cut. Again, some degree of skill is required to apply this device and while it is user friendly it does not exclude the need for knot tying skills.

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Three-legged tie

Securing a continuous suture line can be accomplished two ways. One possibility is to loosen the last loop and use it as the "short tail" for the traditional square or surgeon's knot tying of a 3-legged tie.

Creating the first wrap, grasping the loosened up loop
Laying the first flat knot

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Aberdeen knot

Creating loop

Tying knot

Another method is the Aberdeen knot, which also requires loosening up the last loop. It is also known as the crochet or French knot. Although this knotting technique requires minimal rotation of the instrument, it still demands considerable skill to execute properly.

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Purse string

Circular stitch

Purse sting suture line is basically a continuous circular stitch that goes in and out of the tissue in 5 mm intervals. The purpose is to provide a circular tightening of tissue. Laparoscopically the difficulty is in judging the entrance-exit points correctly.
It is recommended that the course participants begin with the choreographed square knot, and once they have gained confidence, they can try the other methods.

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Extracorporeal knotting

Extracorporeal knot formation

Pushing the knot intracorporeal

These knots are useful when the intracorporeal space is insufficient for the instrument tips to maneuver or if the surgeon lacks intracorporeal knotting skills. These knots work best with slippery monofilament suture materials. A common misconception exists about extracorporeal knots and that is that it requires less skill to tie than intracorporeal knots. On the contrary, to tie extracorporeal knots safely considerable skill and understanding of tissue texture are required. Knots tied with braided suture material have a tendency to lock up to soon, outside the desired location. The most common knot tied extracorporeal is the Roeder knot. Pre-tied ligatures available commercially generally use this knot and after one ligature has been made, this product can be used again by preparing another loop that is secured with the Roeder knot.

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Sliding knot

A half-hitch is tied and then pushed down through the port with a special knot pusher into the appropriate position.  Additional half-hitches are subsequently made in a similar fashion and pushed down on top of each other. While relatively simple, it is cumbersome, minimizes the surgeon's control of the stitch, and can cause excessive tension on the tissues.

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Conclusion

For the surgeon to develop the same level of proficiency and dexterity in the endoscopic environment as he may possess in open surgery is not a simple matter. The use of proper instrumentation (hand, optical, and video), are essential.  Participating in an in-depth, systematic training program in a laboratory setting is essential before applying endoscopic suturing techniques to humans. Successful acquisition of these skills requires that the surgeon be motivated to succeed and willing to invest the time and effort necessary to do so. Succumbing to the temptation of mechanical devices in lieu of acquiring the manual skills results in a questionable dependence on disposable technology and reduces the cost effectiveness of the minimally invasive approach. It is the adoption of endoscopic skills by the surgeon that will expand the surgeon’s capability of performing increasingly advanced endoscopic surgical procedures.

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