Emerging Technologies—Single-Incision Laparoscopic Surgery: How and Why?

by Jenny Choi, MD; Luca Milone, MD; and Column Editor Marc Bessler, MD

This ongoing column investigates current research in the surgical and clinical aspects of obesity treatment and educates bariatric care professionals on the most up-to-date, concrete information on emerging technologies in the field. The first article in 2009’s Emerging Technologies series is authored by our Column Editor, DR. MARC BESSLER, a leading authority in the surgical treatment of obesity, and his colleagues.

Dr. Bessler is the Surgical Director, New York-Presbyterian Hospital Center for Obesity Surgery, and Assistant Professor of Surgery, Department of Surgery, Director of Laparoscopic Surgery, Columbia University College of Physicians and Surgeons, New York, New York.

DISCLOSURES
Dr. Bessler receives research support and is a consultant for Covidien and receives research support from Olympus, Ethicon, and Novare.

Introduction
For many years, large incisions were required to perform abdominal surgical procedures. Although effective, multiple morbidities were associated with this method, including postoperative pain, wound infection, incisional hernia, and prolonged hospitalization. The current rate of wound infection is 2 to 25 percent, and occurrence of incisional hernia is 4 to 18 percent in US patients.[1,2] Some surgeons’ perceptions that complications and morbidities were associated with the size and extent of the incision led them to minimize their incision length. Laparoscopy, prevalent in gynecologic surgery for many years, was widely introduced to the general surgical domain with laparoscopic cholecystectomy more than 20 years ago. By making much smaller incisions that were protected by a port, there was a great reduction in incision-related complications.[3,4] There was faster postoperative recovery, pain reduction, less need for narcotics, respiratory function improvement, decrease in infection and hernias, and better overall cosmesis.[5–7] However, with the introduction of a new technique came a price.

Before the safety of the technique could be verified and standardized, the procedure was introduced with haste, causing higher rates of common bile duct injury and other complications.[8,9] Over time, the complication rates decreased and advantages of minimal, small incisions were recognized and accepted as the gold standard. Surgeons continued to make modifications to reduce the number of incisions. For example, laparoscopic cholecystectomy, which typically requires four incisions, was modified to two or three trocar incisions.[10] Others reduced the size of incisions and instrumentation to 2 to 3mm.

Although endoscopic technology has been widely available, it was initially confined to the luminal walls. However, when accidental puncture of the stomach during polypectomy showed another way to access the peritoneal cavity, the possibility of scarless, incisionless surgery was introduced.[11] Natural orifice translumenal endoscopic surgery (NOTES) was envisioned as perhaps the ultimate form of minimally invasive surgery—with many potential benefits, including complete elimination of wound infection, adhesions, and hernias, reduction of pain and recovery period, minimal anesthesia and analgesia, and no external scar.[2,12–14] Basically, NOTES involves placing a flexible endoscope through one of the body’s natural orifices, such as the mouth, anus, vagina, or urethra, to gain access to a body space to perform surgery.[14,15] Since Kalloo’s transgastric peritoneoscopy in 2004, multiple centers have successfully performed many variations of NOTES in humans, including transgastric appendectomy to complete transvaginal cholecystectomy.[14–21] However, with the advent of every novel technique, there are limitations and shortcomings. Lack of specific instrumentation, safe viscerotomy closure technique/devices, and difficulty with patient recruitment in the US has limited its implementation.[20] Preliminary experience has proven feasible and suggested that several of the potential benefits, such as cosmesis, pain reduction, and shorter recovery, may in fact be realized. Knowing the importance and the potential benefits of NOTES yet realizing current limitations of the technique, surgeons are developing single-incision laparoscopic surgery in parallel, perhaps as a bridge between standard laparoscopy and NOTES.

Single-incision surgery has been given a panoply of acronyms and names, including single-incision laparoscopic surgery (SILS), single-port access (SPA) surgery, laparoscopic endoscopic single-site surgery (LESSS), single laparoscopic incision transabdominal (SLIT) surgery, one-port umbilical surgery (OPUS), natural orifice transumbilical surgery (NOTUS), and embryonic natural orifice transumbilical endoscopic surgery (E-NOTES). SILS has been described since the late 1990s, beginning with appendectomy and cholecystectomy.[24,29] Since then, the technique has been applied to multiple surgical procedures, including gastric banding, sleeve gastrectomy, splenectomy, nephrectomy, colectomy, and adrenalectomy.[24,28] Studies have shown that smaller incisions, including smaller port size, decrease morbidity in both appendectomy and cholecystectomy patients. In comparing patients undergoing needlescopic versus conventional laparoscopic appendectomy, the needlescopic group had a shorter hospital stay (1.3 days vs. 3.2 days), reduced narcotic requirements, and faster return to work (8 days vs. 17 days) than controls.[30] In a similar study pertaining to cholecystectomy patients, the group with downsized trocars reported less incisional pain in the first postoperative week.[31] Based on the results of these studies, it seems logical that eliminating multiple incisions/port sites would further decrease associated morbidity. However, no prospective, randomized study demonstrating clear advantage over standard laparoscopy has been reported.

The tenet of single-incision laparoscopic surgery is to reduce the number of incisions to one, typically at the umbilicus, for multiple trocar placements. This can be accomplished in several ways: a single umbilical skin incision with skin flaps to insert ports through multiple fascial punctures as described by Curcillo, or the use of newly developed systems, such as the Uni-X™ Single Port System (Pnavel Systems, Inc., Morganville, New Jersey), Surgiquest AnchorPort®, TriPort™ (Advanced Surgical Concepts, Wicklow, Ireland), or GelPort® (Applied Medical, Rancho Santa Margarita, California) requiring a larger but single fascial incision for passage of multiple instruments. The required proximity of the trocars at a fixed position illustrates one of the disadvantages of these techniques. The freedom of the hands is relatively restricted, which causes clashing of the instruments, and the fixed port at the umbilicus potentially creates a long distance to the surgical site. This is somewhat contradictory to the traditional teaching of triangulation of instrumentation in laparoscopy, creating a steep learning curve. Thus, the lack of triangulation, pneumoperitoneum leaks, and instrument clashing have been described as real disadvantages of this procedure.[22] Furthermore, there is no long-term data that has examined morbidity of single-incision laparoscopic surgery. Multiple, closely placed fascial punctures have the potential for hernia, and wide skin flaps created to accommodate multiple trocars may result in seroma formation. Still many surgical procedures have been performed safely using these techniques, and variations have been described. As new instruments are developed to accommodate the new paradigm of SILS, it is likely that technical difficulties will be minimized.

Since SILS procedures are relatively new and in evolution, many techniques have been described but no widely accepted standard exists. SILS was first adapted to cholecystectomy and once the technique was shown to be safe and effective for basic laparoscopic procedures, it was applied to some of the technically simpler bariatric procedures. Laparoscopic gastric banding was one of the obvious transitional procedures since the significant incision required for the adjustment port provides the needed space to place multiple trocars. However, laparoscopic banding was more technically difficult due to the camera angles required for dissection of the retrogastric tunnel, the need for retraction of an often-fatty liver from a longer distance, and the need for suturing. As surgeons gained more experience, the technique became more sophisticated, and cosmesis was improved by placing the incision in the umbilicus. With this change, the distance from incision to the surgical field increased and the angle of dissection became more technically challenging. Some have modified this technique by adding a small, second incision for retraction or using specialized ports. With attempts to overcome these obstacles, multiple techniques and instruments have been developed. Because the primary benefit of SILS seems to be cosmetic, most agree that the umbilicus is the preferred incision site; however, it is at this point that the techniques diverge.

Patient Positioning
To perform SILS procedures, the patient can be placed in the supine, split leg lithotomy, or French position. Since the incision and, thus, the fulcrum of all the instruments is at the umbilicus, the French position may be most natural, especially for any foregut cases. However, many procedures can be performed with the patient in supine position with the surgeon and assistant on one side.

Incision and Subcutaneous Flap
When SILS cholecystectomy was first performed, a small 2 to 3cm vertical or horizontal incision was made in the umbilicus and some dissected subcutaneous flaps to more easily place multiple ports. For gastric banding, the placement of the adjustment port requires a subcutaneous flap. This has the potential to result in formation of a seroma and infection of the port. In our experience, two cases of seroma have been observed, but with careful, minimal dissection, this may be avoided. In most SILS procedures, minimal development of the flap is needed to place multiple trocars, but surgeons should be cognizant of this possible complication.

Technique of Entry
Once the incision is made and the fascia is cleared, the entry into the abdomen can be performed in two ways: Veress needle or direct cut down entry. With the Veress technique, the fascia is lifted and the needle is inserted. Once pneumoperitoneum is achieved, a 5-mm trocar is inserted first, followed by the other trocars. Use of a port that allows visualization of tissue layers during entry may be desirable. If the cut down technique is used (for multiple individual trocars, TriPort, or GelPort), a small incision is made in the fascia, and the peritoneal cavity can be palpated prior to placement of the first trocar to avoid possible bowel injury. A small defect is frequently present at the base of the umbilicus and can be gently dilated to allow placement of a trocar. Lack of visualization of subsequent trocars is one of the disadvantages of entry and trocar placement in SILS. Because all the ports are placed alongside one another, their placement is blind. Use of a transparent port for initial entry may allow better visualization. A flexible scope that articulates at least 180 degrees can allow direct visualization of secondary trocars. If the patient has had a previous surgery and is at risk for adhesions, extra care needs to be taken as the trocars are placed.

Trocars
There are many technical challenges to performing single-incision laparoscopic surgery. Unlike standard laparoscopy, all trocars, usually three to four, are crowded into one skin incision. To allow for greater freedom of movement and reduced clashing, a few modified trocar options are currently available and more are in production. Many prefer the trocars used in standard laparoscopy or slightly modified ports. Some of these trocars have smaller heads, lower profiles, and absence of insufflation ports, such as Apple trocars (Apple Medical Corporation, Marlborough, Massachusetts) and TERNAMIAN EndoTIP™ (Karl Storz Endoscopy, Tuttlingen, Germany). This allows freedom of the hands while maximizing use of the incision. Others have placed instruments directly through the fascia without a trocar. Purpose-designed ports include multilumen, single-trocar systems, such as the R-Port (Advanced Surgical Concepts, Wicklow, Ireland), Uni-X single laparoscopic port system, and GelPort (Alexis®) (Figures 1, 2, and 3).[22,23] Recently, Covidien received FDA clearance to market its SILS™ multiple instrument access port.

The GelPort used in SILS is similar to those used in hand-assisted laparoscopic procedures. The GelPort provides a “flexible fulcrum” for insertion and manipulation of a laparoscope and up to three or four 5mm trocars through a single fascial incision. This system also allows the insertion of an instrument directly through the GelPort without the use of a trocar. Given that we do not know the long-term rate of complications of placing multiple trocars so closely together, this technique may also prevent hernias. Lastly, the GelPort technique readily maintains the pneumoperitoneum and avoids the leak commonly encountered with multiple individual trocars.[22] However, a single, larger incision may increase pain, the larger incision size may limit cosmetic benefit, and a specialized port clearly adds cost.

There are now other commercially available, single-incision platforms with built-in trocars specifically made for SILS procedures. These devices require a single fascial incision like the GelPort, but have 3 to 4 ports for instruments, as well as a separate site for insufflation (Figure 4). They have many of the same advantages and problems as the GelPort, but have less flexibility in port size and placement.

Flexible Instruments
In addition to standard laparoscopic instruments, bent or flexible instruments and laparoscopes can be used to minimize the clashing of the instruments. There are instruments that have varying degrees of flexibility and freedom. Novare Surgical Systems, Inc. makes a product line called RealHand® that includes a flexible grasper, needle holder, scissors, and hook that mimic the movements of the surgeon’s wrist (Figure 5).[32] Ethicon (Cincinnati, OH, USA) makes the REALIZE™ Endoscopic Dissector, which has 90-degree flexibility and is used for retrogastric dissection (Figure 6). Other flexible instruments available include tools from Covidien (Norwalk, Connecticut), Pnavel Systems, Inc. (Morganville, New Jersey),[32] and Cambridge Endo—maker of the Autonomy™ Lapro-Angle™ Instruments (Framingham, Massachussetts). Typically, using one flexible instrument and one rigid instrument is adequate to give enough working space to manipulate and dissect tissue bimanually. Also, combined use of long and short instruments keeps the handles and surgeons’ hands from interfering with one another. In our experience, using one flexible instrument is satisfactory, and attempting to use two may be more mentally challenging and cumbersome. One downside of multiple planes of articulation is wrist fatigue, especially since all articulating instruments tend to deflect when force is applied.

Laparoscope
For basic laparoscopic procedures such as cholecystectomy, a standard 5-mm, 30-degree laparoscope provides sufficient visualization of the surgical field. However, for other procedures, the length and visibility provided by the standard laparoscope may pose some limitations. Because there is only one incision, typically at the umbilicus, the distance from the umbilicus to the surgical field may be longer than with the standard laparoscopic technique. For example, gastric band placement or Nissen fundoplication requires close proximity to the hiatus and may require a longer scope for adequate visualization. In these cases, a longer, rigid scope may be an option. For more complex cases requiring two working hands, a flexible tip laparoscope is advantageous. EndoEye laparoscope (Olympus Surgical & Industrial America Inc, Center Valley, PA) allows panoramic view of the surgical field with minimal movements by the operator (Figure 8). Others have used 45-degree laparoscopes (Karl Storz, Tuttligen, Germany) for improved visualization (Figure 7). By manipulating just the tip of the laparoscope with the shaft off line, the viewing angle needed can be obtained while allowing the working ports a higher degree of freedom. (Figure 9 shows SILS gastric banding with 2 rigid instruments, liver retractor, and flexible tip laparoscope.)

Instead of using the traditional laparoscope, some have used the flexible endoscope, as in some NOTES procedures, to perform SILS cholecystectomy. Instead of puncturing through the stomach or the vagina, the endoscope is placed transabdominally for visualization (Figure 10). Some have inserted a double-channel endoscope directly through the fascia, while others have used a 15-mm trocar for insertion of the endoscope.[39] A second trocar is placed for insufflation, smoke evacuation, and retraction. Unlike in SILS, where the surgeon is using a using a laparoscope, the main working instrument is the double-channel endoscope. Once the endoscope is placed, the procedure is performed much like NOTES with slightly less technical difficulty due to distance. Current limitations of this technique, similar to those encountered using NOTES, are that most surgeons lack the required skills and the available endoscopic instruments are not designed for surgical dissection.

Retraction
One of the initial cases of single-incision laparoscopic cholecystectomy described the use of two transumbilical trocars with two transabdominal stay sutures for retraction of the gallbladder.[40] Sutures can allow retraction, reducing the number of ports needed. A suture that enters and exits the abdomen in separate areas and passes through an organ with a locked stitch or clips can allow for “puppeteering” or retraction in different directions. Since then, the use of intrabdominal suture to the anterior abdominal wall with or without endoloop and use of a penrose as a sling have also been described. The use of percutaneous sutures for retraction begs the question of additional punctures and incisions. At what point is it no longer a single-incision procedure? Another technique for retraction involving a magnetic system may be adaptable from its use in NOTES procedures.

Future Technologies
Magnetically anchored and guidance systems (MAGS) are designed to maneuver intra-abdominal instruments by use of an external handheld magnet.[41] The fundus of the gallbladder, for example, can be retracted above the costal margin by coupling the internal component to an external magnet. The graspers are positioned on the gallbladder with assistance from endoscopic biopsy forceps. Magnets may become valuable, but challenges include an exponential decrease in force with thicker abdominal walls and clumping of ferrous objects in the operating room.

Robotic or remotely controlled devices are other technologies that may aid single-incision laparoscopy. The ability to insert instruments and have the surgeon control them remotely can allow degrees of freedom and triangulation not otherwise possible with a single point of origin. Avoiding the need for handles and resulting clashing or interference of instrument motion are significant potential advantages of these systems.

Conclusion
Single-incision laparoscopic surgery is gaining popularity and associated courses are being taught at many centers. This may be for a variety of reasons. Many see a natural progression to minimize the number of incisions from multiple small incisions required for laparoscopy to a single incision. Although neither truly scar-less nor as pain-free as NOTES, it may still offer many advantages. SILS has the potential to improve cosmesis, yet be performed with already existing instruments and what many view as modified laparoscopic techniques.

As with any new surgical technique, there is a learning curve. We have learned from the problems encountered with NOTES that lacking the appropriate instrumentation and adapting to a different setup can be extremely challenging. Although the concept of SILS seems similar to standard laparoscopy, theoretically there are major differences in technique. In fact, some “rules” of laparoscopy need to be “broken” in order to perform SILS. It involves crowding of all the working instruments within one incision, and the basic principle of triangulation is therefore lost to some degree. When associated with inadequate training and experience, these challenges may increase risk of intraoperative injury. Visualization may be obscured due to crowding of instruments, and longer distance from insertion to operative site presents additional challenges. To some degree, we still lack optimal instrumentation to overcome these issues. Given these challenges, is SILS worth performing for improved cosmesis? Is the hope of slightly faster recovery and decreased pain likely?

Before we can answer these questions, there needs to be randomized, prospective studies to compare SILS to standard laparoscopy. The theoretical benefits are obvious, but it is unclear whether the benefits really exist and if they will outweigh the potential risks. This comparison is not unlike the introduction of laparoscopy. Initially, many were skeptical given higher rates of complication, higher cost of instrumentation, and increased operative time. However, it proved to be extremely beneficial for patients and became the gold standard for many procedures. Similar to the development of laparoscopy, it appears that dissemination of the SILS techniques will precede careful study. The fact that SILS seems like an incremental step (i.e., moving trocars to one location) and involves few new instruments makes it easy for surgeons to adopt. Ideally, careful comparison to existing techniques would precede wide application of new technology. Market forces, patient interest, and even industry are driving the advancement of SILS. Although many surgeons are already performing SILS procedures, disciplined, evidenced-based investigations must be performed to determine the proper place of SILS in surgical practice.

We have learned from the introduction of laparoscopy that serious, avoidable complications can occur when embarking on new techniques without adequate training. What specific training is needed and whether credentialing specific to SILS is necessary remain to be determined. Currently, most surgeons performing SILS feel that some specific didactic training and observation of SILS technique is necessary as a minimum. Some feel that hands-on training and proctoring is necessary. Application of SILS lacks any significant level of regulation or monitoring. Clearly, some guidelines need to be implemented to avoid unnecessary complications. As stated, this may involve training in an animate or inanimate lab, proctoring, or simply didactic education with operating room or video observation.

SILS has the potential to offer patients real benefits, but the actual outcomes of SILS will not be positive if training is inadequate. Some feel that SILS will be a bridge to NOTES. While there may be some cross-fertilization between techniques, it is likely that these techniques will develop in parallel because SILS is technically simpler and easier for surgeons and patients to conceptualize. Yet, SILS performed with flexible endoscopes may be a step toward NOTES. In summary, the initial experience of SILS challenges some basic laparoscopic surgical conventions. Experience and technology may allow SILS to be performed widely and improve surgery.

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Address for correspondence
Marc Bessler, MD, Center for Obesity Surgery, Department of Surgery, Columbia University College of Physicians and Surgeons;
New York-Presbyterian Hospital, Herbert Irving Pavilion; 161 Fort Washington Ave, Suite 612, New York, NY 10032; E-mail:

Tags: Emerging Technologies, Single-Incision Laparoscopic Surgery

Category: Emerging Technologies, Past Articles