Instruments and devices used in laparoscopic surgery

INTRODUCTION — Minimally invasive surgery has undergone significant advances and has changed the way operations are performed. Technological advances have produced progressively smaller laparoscopic instruments and higher-quality imaging that allow laparoscopic surgeons to perform precise dissection with minimal bleeding through most dissection planes, even those that are highly vascular.

Adequate hemostasis is essential during laparoscopic procedures to ensure a clear view of the operating field. The need to convert to an open procedure negates the advantages of the laparoscopic approach. Primary prevention of bleeding through the use of various laparoscopic devices to carefully dissect and identify vascular structures prior to dividing them (as needed) is fundamental. However, when bleeding does occur, these devices can also be used to safely and efficiently achieve hemostasis to allow the procedures to continue laparoscopically. (See "Complications of laparoscopic surgery".)

This topic will discuss devices and techniques available for laparoscopic imaging, dissection, and control of bleeding encountered during laparoscopic surgery. Abdominal access techniques are discussed in detail elsewhere. (See "Abdominal access techniques used in laparoscopic surgery".)

LAPAROSCOPIC SURGERY — Laparoscopic surgery refers to surgical procedures that are performed through one or multiple small incisions, rather than through a larger, usually single, incision through the abdominal wall. Advantages of laparoscopy over laparotomy include smaller scars; quicker recovery; decreased adhesion formation [1]; and, for some procedures (but not all), less bleeding, fewer complications, and shorter procedure duration [2-6]. However, in many cases, the risk of major complications (pulmonary embolus, transfusion, fistula formation, major additional unplanned surgery) may be similar for the open and laparoscopic approaches to a given procedure.

Depending upon the nature of the specific surgical procedure, laparoscopic entry can be performed using a closed (Veress needle, optical access) or open technique (Hasson technique). Once pneumoperitoneum has been established, one or more ports are placed through which the camera and instruments are passed. Techniques for laparoscopic entry are reviewed in detail elsewhere. (See "Abdominal access techniques used in laparoscopic surgery".)

CHALLENGES OF LAPAROSCOPIC SURGERY — The laparoscopic operative field and instrumentation have unique technical issues, which can challenge even the most experienced surgeon, particularly if significant bleeding is encountered.

Compared with the open surgical field, the laparoscopic field has:

●A two-dimensional field of view with a loss of depth perception.

●Limited field of view. Instruments may intermittently leave the field of view while manipulating structures. Bleeding or injury to other structures outside the current field of vision (eg, torn adhesion) can occur and may not be immediately recognized.

●Limited working space for laparoscopic instruments. Complete exposure of the operative field can be difficult due to the limited number and size of instruments that can be inserted into the abdominal cavity. The configuration of port placement also depends upon the patient's anatomy, which can present additional challenges.

●Vision can be impaired by irrigation, blood, or body fluids that accumulate on the tip of the laparoscope or at the port sites. Dissecting instruments (eg, monopolar cautery, Cavitron Ultrasonic Surgical Aspirator [CUSA]) also perform poorly when submerged in fluid, and excess splattering can occur during their continued use. The severity of bleeding may be difficult to judge for less experienced laparoscopists. Experience is needed to evaluate the volume of bleeding and determine whether conversion to an open procedure should be performed. (See "Complications of laparoscopic surgery", section on 'Conversion to an open procedure'.)

●Altered light absorption. Bloodied tissues reflect less light than unstained tissues, which can result in difficulties discriminating structures and dissection planes.

●Intra-abdominal smoke and steam from electrosurgical devices used in dissection and hemostasis can obscure vision. Frequent opening of the abdominal ports to clear the smoke can lead to loss of intra-abdominal pressure and pneumoperitoneum, resulting in loss of surgical exposure and instrument placement. The use of smoke evacuation and filtering systems can improve visibility but adds an additional expense to the procedure.

●The laparoscopic camera lens is prone to frequent fogging, particularly early in the case before it has warmed to body temperature. Telescope warmers and antifog solutions are used by some surgeons to reduce fogging during the procedure.

●Semi-paradoxical hand motions (ie, left is right, right is left, down is up, up is down, in is in, out is out, clockwise is clockwise, counterclockwise is counterclockwise).

IMAGING SYSTEMS — Although minimally invasive surgery is a relatively modern addition to the practice of surgery, its roots were established in 1901 when a light scope was first used to look at the intra-abdominal organs [7]. Progress in laparoscopic surgery was limited by a lack of adequate lighting, and technological improvements are primarily responsible for the rapid advancement of minimally invasive surgery in the latter part of the 20^th century [8,9].

Laparoscope — The laparoscope is essentially a rigid endoscope (picture 1) that is used to illuminate the abdominal cavity and capture images during manipulation and dissection of abdominal structures. Flexible-tip laparoscopes and three-dimensional imaging systems are also available. However, the clinical impact they may have is still under investigation. The choice of laparoscope is generally based upon operator preference.

Anatomy of a rigid laparoscope — The rigid laparoscope is a solid metal tube with two channels that has an eyepiece or camera coupler at the proximal end and a light objective at the distal end that gathers the image and transmits it through a collection of rod lenses. The essential elements of a laparoscope are illustrated in the figure (figure 1). Many systems use an integrated all-in-one design.

The first channel of the laparoscope forms a ring that encircles the outer aspect of the scope and is comprised of a bundle of glass fibers that run the length of the scope and transmit light from an external light source to the tip of the endoscope.

The second, center channel of the laparoscope is composed of multiple rod lenses throughout the length of the endoscope, which invert the image [10]. Rod lenses were introduced in the 1950s and have the unique feature of trapping light internally, thus minimizing image degradation. The center channel returns to the ocular end of the scope, which, for modern endoscopes, is frequently connected to a camera. Digital imaging chips located within the camera allow the image from the scope to be transmitted to an external display.

The diameter of rigid laparoscopes ranges from 3 to 12 mm. Small-caliber laparoscopes have poorer image quality compared with their larger counterparts due to less light transmission through the center channel lenses.

The objective is located at the distal end of the scope and can be manufactured at angles ranging from 0 to 120°. This "angle of view" enables the operator to see objects that might otherwise be out of camera view. The 0° lens provides a panoramic view of the abdomen or pelvis. Angled (30°, 45°, 135°) lenses help to see the anterior abdominal wall, work around masses, or work within deeper spaces.

Light source and fiberoptics — Adequate lighting is important for performing laparoscopic surgery safely. For the majority of rigid and flexible scopes, the light source is located separately off the operating field due to its size and the significant heat that is generated by the light bulb. The most widely used bulbs are xenon or hydrargyrum medium arc-length iodide (HMI). These bulbs have a limited life span and need to be changed every 200 to 500 hours of operation. Improvements in light-emitting diode (LED) technology, however, have allowed for longer-lasting options.

Fiberoptic technology is used to carry light from the light source to the light post proximally and transmit it to the distal end of the laparoscope. Fiberoptics provide a greater intensity of light to the abdominal cavity. Light transmission is improved with an increasing number of light fibers, increased diameter cable, and increased power. However, light transmission is reduced if the optic fibers are damaged or broken. Illumination is also reduced at each junction in the system, such as with the use of a beam splitter.

Imager — A high-quality image is essential to performing the procedure safely. The imager is contained within the camera head that is attached to the end of the scope. The camera head also contains a mechanical zoom function and a focus ring. For endoscopic surgery, which uses a flexible endoscope, the imager is located at the tip of the scope and does not require a separate camera unit [11].

The imager is comprised of one or several charge coupled device (CCD) sensor(s), which convert the optical image into an electrical signal. Each pixel of the CCD chip is capable of reading one primary light color (ie, red, green, or blue). Early cameras used one CCD sensor, but improvements in CCD sensors, particularly the ability to make CCDs much smaller, have allowed the placement of three sensors, one for each color, within the camera head. Before the optical image reaches the CCD, it passes through a splitter that separates the light signal into three beams, one for each sensor. This advance has allowed higher resolution of single CCD chips and the development of high-definition cameras to provide more detailed images [12]. Smaller scopes are advantageous for some applications; however, these have smaller imaging chips, which provide an inferior-quality image compared with a larger scope.

Video monitors — Video monitors allow the surgeon and the remainder of the operating team to see the procedure. The camera should be white balanced before being placed into the abdominal cavity. Earlier cameras used a beam splitter that allowed the surgeon to look down the telescope as well as operate from the video monitor, but this decreases the quality of the image and is no longer necessary.

Generally, one or two monitors are used for laparoscopic surgery, one placed within the view of the operating surgeon and one for the assistant surgeon. Still photos or a video copy of the procedure can be recorded.

Three-dimensional imaging — In open surgery, as in daily life, the surgeon is able to see everything in three dimensions (3D); however, in minimally invasive surgery, the field of view is reduced to two dimensions as depth perception is lost during transmission of the image through the lens and camera. Special cameras called stereoscopes use two side-by-side imaging systems, similar to human eyes. Although stereoscopes were initially introduced in the early 1900s, their use still is not widespread [13,14]. The major limiting factor pertains to the manner in which the image should be displayed so the brain will perceive the image in three dimensions. Wearing special glasses, similar to 3D movie glasses, is one option; however, this is not practical in the operating room where the surgeon may need to direct their vision to other matters. Although technology exists to display 3D images without wearing glasses, it is not commercially available and requires the screen to be viewed at a particular angle and is not likely practical in the operating room environment.

One area of minimally invasive surgery that has taken advantage of 3D imaging is robotic surgery. With robotic systems, two separate cameras are used in a manner that mimics human eyes. The image is optimized digitally and transmitted to the command station where the surgeon sits. The surgeon is able to see the image in three dimensions by looking through a display system in which each eye has its own screen. This method tricks the brain into seeing things in 3D, giving the surgeon a view that is more similar to that of open surgery [15].

Flexible endoscope — Flexible endoscopes, which are typically used to perform upper endoscopy and colonoscopy, can be used instead of the rigid laparoscope and may be of particular use during single-incision surgery. (See 'Laparoscopes for single-incision surgery' below.)

The flexible gastroscope was developed in 1952 by a Japanese team of clinicians. Early devices transmitted the image from the head of the scope to an externally located imager, but these were plagued by poor image quality [16]. The turning point for flexible endoscopy came with advances in imaging that reduced the dimensions of the imager and moved it from an external to internal position, overcoming many of the limitations of prior endoscopes. With this technique, the image is captured internally as a digital signal and then transmitted externally, rather than as an optical image internally that is converted to a digital signal externally. Improvements in image quality enabled incorporation of working channels for passing various instruments through the flexible endoscope.

Laparoscopes for single-incision surgery — The laparoscope used during single-incision surgery needs to help avoid clashing of the instruments outside or within the abdomen [17]. Smaller-diameter (5 to 10 mm), low-profile cameras are available with in-line light cords to reduce extracorporal bulk.

An angled camera lens can be used to image above or below the plane of other instruments. Another option is a flexible laparoscope, which provides a 100° field of view. Some flexible systems allow the surgeon to toggle between the rigid and flexible tip with the push of a button. A variable viewing laparoscope allows adjustment of the viewing direction of the lens from 0 to 120°, rather than changing the orientation of the shaft, as with the flexible scope.

Ultrasound — Ultrasound has been a useful adjunct to open surgery since the 1980s for numerous applications, including localization of intrahepatic lesions and for evaluating the biliary tree, evaluating pancreatic cysts, and defining the extent of gastrointestinal malignancies. Once laparoscopic cholecystectomy replaced open cholecystectomy as the preferred approach, it became necessary to develop an ultrasound probe that could be introduced through a laparoscopic port. Studies comparing laparoscopic ultrasound with intraoperative cholangiogram for the detection of common bile duct stones have shown similar sensitivities and specificities [18-21]. For this application, ultrasound has the advantage of eliminating radiation exposure.

In vivo fluorescence imaging — Near-infrared fluorescence (NIRF) imaging is an emerging clinical technology that requires administration of a fluorescence-imaging agent that can be excited at near-infrared (NIR) wavelengths of ≥760 nm [22]. When illuminated with NIR light of an appropriate wavelength, the imaging agent within the tissues is excited and generates fluorescence that is collected to form an NIRF image. NIRF imaging depicts how the imaging agent is distributed in live tissues intraoperatively and can help:

●Identify the common bile duct during cholecystectomy (picture 2) [23]

●Evaluate for bile leak during liver resection [24]

●Assess bowel perfusion during colorectal resection [25]

●Detect sentinel lymph nodes during gynecologic surgery for endometrial or cervical cancer [26]

Indocyanine green (ICG) is the only fluorescence image agent that has been approved for human use. It can be injected intravenously or around a lesion of interest. Intravenous administration of ICG permits study of tissue perfusion during colorectal surgery. Circulating ICG is eventually excreted into the bile by the liver, a process that permits imaging of the liver and biliary tree during hepatobiliary surgery (including cholecystectomy). For sentinel lymph node mapping, ICG is injected around the tumor rather than intravenously.

Successful NIRF imaging also requires a suitable excitation light source, optics that filter out backscattered excitation light, and detectors that capture and analyze fluorescent signals [22]. Laparoscopic surgery operates in near darkness and utilizes a dedicated light source and charged-coupled device (CCD) detectors, all features that can be adapted for NIRF imaging. Commercially available systems use laparoscopes and cameras that can operate in both visible and NIR light to generate images for both conventional laparoscopy and NIRF fluorescence imaging [27].

LAPAROSCOPIC TROCARS — Devices and methods used to establish abdominal access are discussed elsewhere. (See "Abdominal access techniques used in laparoscopic surgery".)

DEVICES FOR DISSECTION — Almost all standard instruments available for laparotomy are available in a specialized form to fit through a 3 to 20 mm port. Nearly all laparoscopic instruments are available in a reusable, disposable, or hybrid form (part of the instrument is disposable and part is reusable). Disposable instruments are typically less cost effective, although they have the advantage of being available (when properly stocked), and the cutting edges are always sharp, whereas nondisposable instruments may be in the process of cleaning and resterilization, particularly where many laparoscopic surgeries are performed.

Grasping instruments — Grasping forceps have been designed for tissue manipulation and may be locking (ratcheted) or nonlocking (non-ratcheted). Some forceps are broad and flat, while others are finer and made for delicate tissue handling (picture 3 and picture 4). Toothed forceps are used to retract tissue, such as for grasping the fundus of the gallbladder or grasping ovarian cysts. Forceps with pointed ends are used for tissue dissection and surgical plane development.

Atraumatic tissue-grasping instruments have double action and curved jaws and are operated by either scissors or a spring-handle. A disposable Babcock-type atraumatic grasper with a ratcheted scissors handle can be particularly useful in handling the mesentery or adnexal structures. Biopsy forceps can be used as a grasping instrument but lead to tissue trauma.

Instruments for single-incision laparoscopy — Flexible and articulating instruments are available to address the problems of hand clashing and instrument crowding during single-incision laparoscopic surgery. These instruments enter the patient in the midline and parallel to each other, but intra-abdominally they approach the operative field more laterally and from different angles.

While not all types of laparoscopic instruments are available with these flexible articulating capabilities, the essential instruments for minimally invasive surgery (eg, Maryland graspers and scissors) are available with these features (eg, Roticulator, RealHand, Spider) [28]. Flexible articulating energy devices are not yet available, but the use of rigid energy devices along with articulating graspers for retraction allows sufficient exposure to accomplish single-incision surgery.

Instruments for mini-laparoscopy — Mini-laparoscopy, also referred to as needlescopic surgery, utilizes instruments with shaft diameters ranging from 1.9 to 3.5 mm (trocar diameters from 2.2 to 4.2 mm) [29]. Modern mini-laparoscopic instruments have improved functionality (multiple effector tips, rotatable and insulated shafts with electrosurgery capability) and durability compared with earlier instruments. Depending upon the manufacturer, these instruments can be reusable or disposable and can be used with or without trocars.

Mini-laparoscopy has been most widely used in gallbladder surgery. Compared with standard laparoscopic cholecystectomy, mini-laparoscopic cholecystectomy offers similar outcomes but improved cosmesis. (See "Laparoscopic cholecystectomy", section on 'Needlescopic cholecystectomy'.)

Suction and irrigation — Suction and irrigation are important for all types of laparoscopic surgery. Irrigation is used to clear debris or blood when bleeding is encountered. Irrigation can also be used for hydrodissection and creation of tissue planes. A variety of laparoscopic suction instruments have been designed to remove irrigation fluid or intraperitoneal air and smoke. Combination suction/irrigation devices are also available (picture 5). A large-bore device is ideal for removing blood clots when brisk bleeding is encountered.

Tissue removal — There are several good alternatives available to the surgeon to remove large volumes of tissue without increasing the size of the laparoscopic access incisions. It is important to observe tissue that will be removed from the moment it is divided from other tissues to its delivery through the abdominal wall regardless of whether or not it is removed in a tissue bag. It is particularly important to always monitor any morcellating devices that are used to prevent injury to adjacent tissues, should the device break through the tissue bag.

Morcellators — Tissue morcellators are effective for reducing the volume of large tissue masses into smaller fragments to allow their removal through a laparoscopic port (eg, spleen). Manual and automatic morcellators are available. Automatic morcellators are more expensive but can save time when large amounts of tissue need to be removed. Devices are available from several manufacturers.

The use of morcellators is not without the potential for complications. In a systematic review that included a search of the Medical Device Reporting (MDR) and Manufacturer and User Facility Device Experience (MAUDE) databases, a total of 55 complications were identified from 1992 to 2012 [30]. These included injuries to the intestines, vascular system, kidney, ureter, bladder, and diaphragm, and 20 percent involved more than one organ. Most injuries were identified and treated intraoperatively, but six patients subsequently died. Factors that contributed to acute morcellator-related complications included surgeon inexperience, lack of training, lack of device control, use of the device without direct vision, and device malfunction [30,31]. A range of procedures was associated with the reported morcellator injuries across all surgical specialties. No single manufacturer was solely associated with the reported visceral or vascular injuries. In addition to these short-term mechanical complications, long-term complications reported in the literature included retained or parasitic tissue, leiomyomatosis, dissemination of cancers (ovarian, renal, endometrial lesions, sarcoma), and dissemination of endometriosis and adenomyosis. One manufacturer has voluntarily recalled its device worldwide over these concerns. Issues pertaining to the use of morcellators during laparoscopic gynecologic surgery are reviewed separately. (See "Uterine fibroids (leiomyomas): Differentiating fibroids from uterine sarcomas".)

Tissue bags — Tissue bags can be used to isolate tissue (eg, tumor, infected appendix) prior to removal with or without morcellation (picture 6). The tissue bag can be removed through a secondary port site or through the infraumbilical port once the camera has been removed. For some (eg, appendectomy [32]), but not all, types of laparoscopic surgeries, the use of a tissue bag may decrease the risk of surgical site infection.

Tissue dilators can be used for stretching a 10 mm port to become a 20 mm port, or, if this is not sufficient, the port incision can be enlarged to remove the tissue.

DEVICES FOR HEMOSTASIS — Most devices used for dissection and hemostasis in the laparoscopic environment are adapted from open surgery. Topical hemostatic agents are discussed in detail elsewhere. (See "Overview of topical hemostatic agents and tissue adhesives".)

Surgical clips — As with open surgery, U-shaped hemostatic clips are used to prevent bleeding from vessels encountered during dissection. The vessel is identified, dissected, and then clipped prior to division of the vessel. In laparoscopic surgery, titanium clips are used instead of stainless steel because titanium does not magnetize and is therefore easier to handle. A variety of clip sizes are available for 5 and 10 mm disposable clip appliers. Reusable clip appliers can also be used. However, there is a tendency for the clip to fall off the reusable applier, and the extra time needed to reload the device limits its usefulness in laparoscopic surgery.

Standard U-shaped hemostatic clips can dislodge as a result of arterial pulsation or manipulation of the operative field during further dissection. Multiple clips (up to five) can be applied, as needed. Caution is advised when using standard clips to occlude vessels with a diameter more than 3 mm.

A polymer ligation clip system (eg, Hem-o-lok) contains a self-locking mechanism that may decrease slippage from larger vessels (picture 7). Vessels with diameters up to 16 mm can be managed with these clips. Prior to deploying the clip, the vessel should be dissected free of surrounding structures because the hook-like locking mechanism can easily perforate adjacent tissues (eg, veins). Slippage of locking clips can occur, which is more likely if the clip is applied to a vessel at an angle other than 90° or the vessel cuff length is <1 mm [33].

Locking clips are useful in situations where it is important to securely control a pedicle but preserve vessel length (eg, donor nephrectomy, splenectomy, adrenalectomy, pulmonary resection, colectomy). Retrospective reviews have concluded that polymer-locking clips for donor nephrectomy provide rapid control and are economical [34-37]. Although generally safe and reliable, serious complications, including death, have been reported following slippage of the clips used during donor nephrectomy [38].

Suture ligation — Suturing tissues and placing ligatures during laparoscopic surgery are complex technical skills. Intracorporeal knot tying avoids excessive tension and is preferable to extracorporeal knotting when tissue is friable or tears easily. Ready-to-use, pre-tied endoloops for primary vessel ligation and hemostasis are commercially available [39,40]. Endoloops are often used for hemostasis when a tissue pedicle can be easily "lassoed" by the loop (eg, laparoscopic appendectomy, laparoscopic cholecystectomy) [41,42].

Suture ligature may be needed for hemostasis of bleeding staple lines when cautery or clip application fails or is not desirable. High-risk staple lines (eg, stapled gastrojejunostomy in a gastric bypass) are best controlled with suture ligature, particularly if brief bursts of low-voltage electrocautery have been ineffective. Excessive electrocautery of the staple line may lead to tissue necrosis and gastrointestinal leakage due to thermal spread.

Surgical staplers

Gastrointestinal — In laparoscopic surgery, bowel resection and anastomosis are performed with stapling devices similar to those used in open surgery, although with longer handles. Control of bleeding at the cut tissue edges following staple deployment can be more technically challenging in the laparoscopic field. (See 'Challenges of laparoscopic surgery' above.)

Additional buttressing materials have been added to the jaws of laparoscopic stapling devices to improve hemostasis. Buttressing materials can be biologic (eg, bovine pericardium) or synthetic.

In a randomized trial of 34 patients, significantly fewer staple line bleeding sites were present in patients randomized to a reinforced staple line compared with those with unreinforced staple lines for all tissue types studied (gastric tissue [0.4 versus 2.5 sites], jejunal tissue [0.1 versus 0.6 sites], mesenteric tissue [0 versus 0.8 sites]) [43]. The potential advantage of decreased bleeding with routine staple line reinforcement needs to be balanced against the additional cost of the device and a lack of a clear benefit in reducing anastomotic gastrointestinal leak rates [44-48].

Vascular — Special vascular laparoscopic staplers are used to divide major arteries and veins. Vascular staplers generally require a 12 mm port for insertion. The stapler cartridge typically has six rows of staples with three rows of staples on each side of the divided tissue (picture 8). In an experimental porcine model, vascular staplers have been shown to seal vessels (arteries up to 17 mm, veins up to 22 mm) to burst pressures (>310 mmHg) three times more than mean systolic pressure [49].

Choosing the appropriate staple height is important. The final fired staple height depends upon the stapler, the selected stapler cartridge, and the tissue itself. A staple cartridge with staples that are 2.0 to 2.5 mm in height provides excellent hemostasis for most larger arteries, provided the vessels can comfortably compress to 0.75 to 1.0 mm. Newer staplers (eg, Echelon and the Endo GIA) employ a technique known as tissue gap control where the final fired staple height is consistent across the length of the staple line. Each individual manufacturer can provide surgeons with specifications for its commercially available staple cartridges, which can vary from manufacturer to manufacturer.

In general:

●For a 2.0 mm cartridge, final tissue compression should be 0.75 to 1.0 mm.

●For a 2.5 mm cartridge, final tissue compression should be 1.0 to 1.5 mm.

●For a 3.5 mm cartridge, final tissue compression should be 1.5 to 2.0 mm.

Using too long or too short a staple will lead to bleeding after the stapler is fired. A short staple fired through thick tissue that cannot be compressed to the final staple height will not interlock properly or will rip through the tissue. Conversely, too long a staple will not adequately compress the tissue, and bleeding will occur through the staple line.

Hemostasis of residual bleeding through a staple line can be controlled in several ways. A short burst of electrocautery to the compressed tissue at the free edge of the staple line is successful in most cases. Application of titanium clips to the bleeding site of the staple line is another option. Suture ligature and the application of topical hemostatic agents to the staple line can also be effective and may be preferable in gastrointestinal staple lines. (See 'Suture ligation' above and "Overview of topical hemostatic agents and tissue adhesives".)

Electrosurgery — Electrosurgery refers to the coagulation and cutting of tissue using high-frequency electrical current [50]. Both monopolar and bipolar electrosurgical techniques are used in laparoscopic surgery. The basic principles of electrosurgery are discussed in detail elsewhere. (See "Overview of electrosurgery".)

A wide variety of standard disposable and nondisposable laparoscopic instruments have a cautery attachment for monopolar current, including the scissors, hook, spatula, and dissectors. Insulation breaks on these instruments will allow transmission of stray current outside the intended field of dissection (picture 9). Thermal injury may not be apparent at the time of the injury, and delayed hollow viscus perforation or hemorrhage can occur as necrotic bowel or vascular tissue sloughs [51].

Bipolar electrosurgery minimizes the risk of damage to adjacent tissue by containing electrical current between the jaws of the forceps. However, the application of traditional bipolar devices to laparoscopic surgery is limited because traditional bipolar devices do not have cutting ability, cannot be applied over a broad surface, and cannot be used for larger vessels.

Advanced bipolar sealing — Advanced bipolar devices (eg, LigaSure, PlasmaKinetic, EnSeal) combine bipolar current together with tissue apposition and compression to create a tissue seal (picture 10). Bipolar sealing is used to manage blood vessels contained within other tissue (eg, omentum, mesentery) (picture 11) or vessels that have been circumferentially dissected (picture 11). Advanced bipolar sealing devices provide excellent hemostasis for vessels up to 7 mm.

In an experimental study, the burst pressure of sealed vessels was two to three times greater than mean systolic blood pressure (>300 mmHg) [52]. A trial of 60 patients randomly assigned to bipolar sealing versus suturing for hemostasis during hysterectomy found significantly less blood loss (69 versus 127 mL) and shorter operating times (39 versus 54 minutes) in the bipolar sealing group [53].

Less lateral thermal spread occurs with bipolar sealing compared with monopolar electrocautery, for which thermal spread can be as wide as 25 mm [54]. With bipolar sealing, lateral thermal spread increases slightly as the diameter of the treated vessel increases. For a 2 to 3 mm vessel, the maximal thermal spread is about 1.5 mm, whereas for a 6 to 7 mm vessel, the maximal thermal spread is approximately 3 mm [52]. (See "Overview of electrosurgery".)

Ultrasonic desiccation — Ultrasonic devices (eg, Harmonic scalpel, UltraCision, Cavitron Ultrasound Surgical Aspirator [CUSA], TissueLink, LOTUS) convert electrical energy into mechanical energy, which produces cutting and coagulation effects. In response to electric current, a piezoelectric crystal located at the tip of the instrument vibrates at approximately 55,000 Hz, generating mechanical forces that rupture cells and form a coagulum. The range of peak tissue temperatures is much lower (60ºC to 100ºC) compared with those produced by electrocautery (200ºC to 300ºC).

In general, the Harmonic scalpel can be used in just about any abdominal laparoscopic procedure when hemostatic dissection with relatively little lateral thermal spread to neighboring tissue is desired (eg, cholecystectomy, hysterectomy, colorectal surgery, bariatric surgery, liver surgery, splenectomy) [55-60]. The main disadvantage of ultrasonic dissection is poor hemostasis with the division of larger vessels (≥4 mm). A newer version of the Harmonic scalpel, the Harmonic ACE, may be capable of handling vessels up to a maximum of 5 mm due to a higher velocity of transaction.

One trial randomly assigned 120 patients undergoing laparoscopic cholecystectomy to traditional hemostatic clipping of the cystic duct and artery with cautery for gallbladder dissection from the liver compared with use of the Harmonic scalpel [59]. No cystic duct stump leaks occurred in either group. Patients in the ultrasonic dissection group experienced fewer intraoperative gallbladder perforations (10 versus 30 percent) and shorter median operative times (32 versus 40 minutes).

The CUSA is another ultrasonic device. Tissue is fragmented, rapidly irrigated, and aspirated away from the dissection field. The CUSA device is used primarily for open liver resection; however, limited experience has demonstrated feasibility for laparoscopic liver resection. The liver parenchyma is destroyed, leaving larger vessels intact to be managed by other means such as clipping, LigaSure, Hem-o-lok clips, or vascular staplers. (See "Overview of hepatic resection" and "Open hepatic resection techniques".)

Radiofrequency ablation — Radiofrequency ablation devices generate a high-frequency alternating current in the radio range of frequencies (460 to 500 kHz), which is transmitted through an electrode placed into the tissue under ultrasound guidance. Activation of the device causes focal tissue destruction at the tip of the electrode.

Radiofrequency ablation has been applied to laparoscopic liver resection [61,62]. The technique consists of ultrasound-guided placement of the electrode to target segmental and subsegmental portal, arterial, and feeding vessels prior to liver resection. Once these vessels have coagulated, the liver becomes ischemic in the treated vascular distribution (figure 2). Parenchymal resection is then performed in a relatively bloodless field. In one case series of 30 patients, blood loss was less than 120 mL with the use of this technique [62]. (See "Overview of hepatic resection" and "Open hepatic resection techniques".)

Laser fulguration — Lasers use light energy at wavelengths specific to the target tissue to produce their effects. (See "Basic principles of medical lasers".)

Lasers are commonly used in laparoscopic gynecologic (eg, endometriosis) and urologic (eg, prostatectomy, partial nephrectomy) procedures and are discussed in separate topic reviews [63,64]. (See "Overview of endometrial ablation" and "Surgical treatment of benign prostatic hyperplasia (BPH)".)

When used in laparoscopic surgery, lasers can cause significant tissue vaporization and smoke and can spread liquefied tissue during instrument manipulation. General abdominal laparoscopic surgery rarely requires the use of surgical lasers due to the ready availability of alternative modalities.

Other devices — Not all devices used successfully in open surgery are suitable for laparoscopic surgery. One example is the argon beam coagulator. This device uses monopolar electrocautery to produce a coagulated surface with very little smoke by passing electric current through a stream of ionized argon gas to blow away blood and debris from the surgical field. High-flow infusion of argon gas can increase abdominal pressure, limiting its usefulness in laparoscopic surgery. In addition, the argon beam coagulator does not provide dissection or control of larger vessels; argon gas embolization has been reported in association with liver resection [65].

Choice of device — The availability of the more sophisticated devices determines their usage under most circumstances. The choice of technique is generally according to the surgeon's preference and experience. There are few trials that directly compare devices.

●Fatty structures, such as the omentum and mesentery, are best addressed with an ultrasonic energy source such as the Harmonic scalpel. This device produces rapid hemostatic dissection of these structures. When vessels within the mesentery exceed 5 mm in diameter (eg, inferior mesenteric artery), advanced bipolar sealing devices, such as the LigaSure, may be more useful. (See 'Ultrasonic desiccation' above.)

●Gastrointestinal tissues (ie, esophagus, stomach, small and large bowel) are best divided with endoscopic linear cutting staplers rather than thermal methods. Cutting staplers divide the tissue along precisely selected lines and provide hemostasis without the risk of lateral thermal spread, which can compromise the integrity of the subsequent anastomosis. However, an ex vivo study evaluating mesenteric vessel sealing found effective sealing for ultrasonic (Harmonic ACE, LOTUS) and bipolar sealing (LigaSure) devices for mesenteric vessels to 1.25 mm. (See 'Gastrointestinal' above.)

●Vascular structures up to 7 mm can be managed with an endoscopic linear vascular stapler or advanced bipolar sealing device. For laparoscopic splenectomy, both Endo GIA and LigaSure are safe and effective for division of the hilar vessels. In one study, LigaSure took less time and was associated with less intraoperative bleeding and need for transfusion compared with the use of a linear stapling device [66]. Arterial structures between 7 and 15 mm should be divided with a vascular stapler. For larger arteries and veins, we prefer suture ligation. (See 'Advanced bipolar sealing' above and 'Vascular' above and 'Suture ligation' above.)

●Solid organ dissection and hemostasis can be achieved with either the CUSA or radiofrequency probes. (See 'Ultrasonic desiccation' above and 'Radiofrequency ablation' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Laparoscopic and robotic surgery".)

SUMMARY AND RECOMMENDATIONS

●Advantages of laparoscopic surgery – Laparoscopic surgery has several advantages over laparotomy, including smaller scars; quicker recovery; decreased adhesion formation; and, for some (but not all) procedures, less bleeding and shorter procedure duration. However, the risk of major complications (pulmonary embolus, transfusion, fistula formation, major additional unplanned surgery) is the same for the two surgical approaches. (See "Overview of gynecologic laparoscopic surgery and non-umbilical entry sites", section on 'Laparoscopy versus laparotomy'.)  

●Challenges of laparoscopic surgery – The laparoscopic field presents unique technical challenges that include limited depth perception, limited field of view, limited working space, and impaired visibility from altered light absorption, smoke, fogging of the laparoscope lens, or blood on the lens. (See 'Challenges of laparoscopic surgery' above.)

●Laparoscopic equipment – Almost all instruments available for laparotomy are now available in specialized form for laparoscopy. Instruments and devices that are used in laparoscopy include the laparoscope (camera), ultrasound, trocars and port devices, and instruments for dissection and hemostasis. (See 'Imaging systems' above and 'Devices for dissection' above and 'Devices for hemostasis' above.)

●Devices for dissection and hemostasis – Primary prevention of bleeding during dissection is essential during laparoscopic surgery because even minor bleeding can increase the degree of complexity of the operation and lead to complications. A variety of sutures, clips, and stapling devices are available for dissection and hemostasis during laparoscopic surgery. Surgical clips are easy to apply, readily available, and useful for vessels ≤3 mm but have a tendency to slip off. Self-locking polymer ligation clips have been developed for larger vessels. Endoscopic staplers divide larger vessels, and the correct choice of a stapling device and stapler cartridge is essential to minimize the risk of bleeding from the staple line. (See 'Suture ligation' above and 'Surgical clips' above and 'Surgical staplers' above.)

Electrosurgical devices used for dissection and hemostasis in laparoscopic surgery include monopolar and bipolar electrocautery, advanced bipolar sealing systems, ultrasonic desiccation, radiofrequency ablation, and laser ablation. Monopolar cautery is commonly used in conjunction with laparoscopic instruments and can be used for both dissection and hemostasis. Excessive thermal injury to the target tissue and injury to nontarget tissues can occur if settings are inappropriate or current strays. Traditional bipolar devices are not typically used in laparoscopic surgery, but advanced bipolar vessel sealing systems combine tissue compression and bipolar cautery to divide larger vessels. Ultrasonic dissectors cut and coagulate tissue simultaneously. (See 'Electrosurgery' above.)

The choice of device for dissection and hemostasis during laparoscopic surgery is generally according to device availability and preference and experience of the surgeon. In general (see 'Choice of device' above):

•Fatty structures such as the omentum or mesentery are divided with an ultrasonic dissector. When mesenteric vessels >5 mm in diameter are encountered, an advanced bipolar sealing device should be used (if available) or the vessel suture ligated.

•Gastrointestinal tissues should be divided with endoscopic linear cutting staplers to provide hemostasis and a precise line of division for the subsequent anastomosis.

•Larger vascular structures (7 to 15 mm) can be divided with a vascular endoscopic linear cutting stapler or suture ligated.

•For solid organ (eg, liver) dissection and hemostasis, the Cavitron Ultrasound Surgical Aspirator and radiofrequency probes have been used successfully.