The journey of laparoscopy, which has now reached single incision and robotic surgery, began with our quest to find ways to reduce surgical morbidity. 1 Since these first steps were taken, gynecologic surgery using minimally invasive techniques has continued to change rapidly. With computerized design and microchip-controlled safety features, laparoscopic surgeons are dependent on the equipment and need to understand the electromechanical functions of the instruments. In this ever-changing environment, understanding the properties of commonly used surgical instruments is critical. Essential equipment for any laparoscopic procedure includes: endoscope, camera, light source, video monitor, inflator, trocar, and surgical instruments. However, there are many variations of each.
Disposable or reusable?
The cost-effectiveness of single-use versus reusable instruments is a topic of debate. Instrument selection is multifactorial and depends on functionality, reliability, and cost. Therefore, in most laparoscopic procedures, a combination of disposable and reusable instruments are used. Disposable trocars and scissors are typically used, while reusable instruments can be graspers, coagulation spatulas/hooks, and needle drivers. Commonly used laparoscopic instruments are described below.
uterine manipulator
These allow for uterine positioning and enlarge the operating space. There are several uterine manipulators to choose from - HUMI® (Cooper Surgical), RUMI® (Cooper Surgical), Spackman, Cohen, Hulka, Valtchev, Pelosi, and Clearview® (Endopath). Some are reusable and some are disposable. Most come with a channel to perform color pipes; however, some (such as Hulka tenaculum and Pelosi) lack this channel. With 210˚, Clearview has the greatest range of motion in the front-to-back plane. The axes of Hulka tenaculum, Spackman, and Cohen are straight, which hinders their range of motion and limits their use in advanced laparoscopic procedures. 2
Figure 1. Trocar sleeves or collars in different textures.
Veress needle
This is a specially designed needle with a blunt, spring-loaded inner needle and a sharp outer needle to achieve pneumoperitoneum when performing closed laparoscopy. It is available in disposable and reusable form in 12cm or 15cm lengths.
Most injuries in minimally invasive procedures are associated with primary port insertion, leading to unresolved debate about the benefits of various access techniques (open, closed, or direct access). There is no evidence that any single technique is better at preventing major vascular or visceral complications, although closed access has a higher risk of failure. A recent Cochrane review concluded that direct access to blood vessels carries a lower risk of injury compared with use of a Veress needle. 3
Trocar/Cannula
These are used to create small channels through the abdominal wall and are available in different textures (see Figure 1). Disposable and reusable trocars are available in a variety of sizes and share the following common parts:
The sharp tip cuts an access path through the abdominal wall, while the blunt tip pulls tissue apart to gain access to the peritoneal cavity.
Sleeve: is the working channel. The trocar sleeve or collar can be textured on the outer surface of the trocar to help secure it to the abdominal wall. Some have an internal inflatable balloon and plastic/rubber ring at their tip to provide fixation.
Valves: Different valve systems prevent trocar leaks and allow insertion of instruments.
Side Port: Many trocars have a side port that can be used for inflation or exhaust.
Laparoscopy
Telescopes used in laparoscopy vary in size from 2mm to 12mm. The 10mm size is the most commonly used size in gynecology. Like a hysteroscope, a laparoscope can be viewed from 0˚, 30˚, or 45˚. In the squint range, the line of sight is directed away from the light source attachment. The 0˚ telescope provides an anterior view corresponding to the natural approach and is preferred by most gynecologists. It is useful if less experienced helpers are available. Swivel 30˚ telescope to expand field of view, good for complex situations. A 45˚ endoscope is useful in single-incision laparoscopy but is uncommon. Each laparoscope has a number engraved on the eyepiece that designates the viewing angle.
Figure 2. A series of grippers.
Instrument size
The most common diameter of laparoscopic instruments is 5 mm, but they range from 2-12 mm. Instrument shafts with narrower diameters (less than 5mm) are less rigid and therefore more flexible and less fragile than wider versions. Standard instruments range in length from 34-37 cm. For obese patients or single-site laparoscopy, the 45 cm long instruments are useful.
non-energy equipment
Most laparoscopic instruments offer only four degrees of freedom of motion: in/out, up/down, left/right, and rotation. Also, certain devices called articulating/rotating instruments offer angles at their tips, which are especially useful for triangulation when performing single-incision laparoscopy. 4
Grippers and scissors typically have an insulated sheath, a central working device, a handle and the ability to swivel the working end.
The loop handle is similar to the traditional loop handle on most needle holders used in open surgery. They can be in line or at a 90° angle to the working axis. Some handles fall in between:
The pistol grip allows for the integration of multiple functions; and
The coaxial handle is on the axis of the instrument.
The handles have different types of ratchets that provide a locking mechanism.
Scissors with curved tips similar to Metzenbaum's are usually used. Most endoscopic scissors can also be attached to electrosurgical devices. Scissors are produced with various tips.
Grabbing jaws (see Figure 2) can be single-acting (one fixed jaw and one articulating jaw) or double-acting (both jaws are articulating). Single-action jaws close with greater force, ideal for instruments such as needle drivers. The dual action opens the jaws wider so they are better suited as dissection tools. Many gripper variants exist, with different surface properties on the inside of the jaws, depending on the intended use:
Trauma: Deep serrated or pointed for a firm grip.
Non-traumatic: finely serrated for gentle handling.
Likewise, the laparoscopic tenacula is also available with single and double toothed jaws.
There are several types of needle drivers available, and the choice largely depends on the surgeon's preference. The lower jaw is either curved or straight. They usually have flat or finely serrated gripping surfaces that allow them to grasp needles from all directions. Certain needle holders (called self-resetting) have a dome-shaped indentation in the jaws that automatically orient the needle in a vertical orientation, making it easier to grasp the needle. However, indentation can make it harder if the needle needs to be loaded at an oblique angle. As mentioned earlier, needle drivers also come in various types of handles (e.g. finger grip, palm grip, pistol grip).
Fibroid screws are in the shape of a probe with a corkscrew tip. They are often used during myomectomy.
A suction irrigator is a multipurpose device. Most use horn valves, but some use slide valves. Irrigation systems can be powered by various mechanisms, including pressure bags or pumps. The omentum, fallopian tubes, or bowel may be aspirated by the suction probe, and attached tissue must be loosened carefully and gently.
The aspiration needle is a 16/22 gauge needle used to aspirate and inject fluids.
There are two types of knotters to choose from: closed and open. Both have their pros and cons.
energy device
Energy sources include monopolar, bipolar, advanced bipolar, harmonic, combining and shredder equipment. Monopolar devices are commonly used to incise the vaginal cuff during endometriosis ablation and laparoscopic hysterectomy. Various types of monopolar hooks and spatulas can be used, and most scissors have attachments for attaching monopolar leads.
Bipolar devices contain a continuous waveform of electrical current between the jaws, thus reducing the chance of damage to adjacent tissue. They achieve tissue sealing and hemostasis through thermal coagulation, although they lack cutting ability. The classic bipolar device is the Kleppinger bipolar forceps. There are now several types of bipolar devices, many of which are grasper forms. 5
The surgical development of energy devices, especially with advanced bipolar capabilities, has been at the center of the exponential growth of laparoscopic surgery. Part of the growing popularity of these devices is the fact that they are now sometimes used in open surgery and even vaginal surgery. 6
Bipolar devices such as LigaSure™, Gyrus PKS™, and EnSeal® provide hemostasis in vessels up to 7mm. They provide low voltage, have impedance-based feedback to modify the energy delivered, and regulate tissue temperature below 100°C. The bipolar energy thus delivered denatures the collagen and elastin in the vessel wall. Denatured tissue, tissue opposition, and pressure seal off the vessel wall in a process called coagulation of the junction. These devices reduce thermal spreading, charring, and sticking compared to conventional bipolar instruments. However, some of these devices require specialized electrosurgical equipment and are expensive. 7
LigaSure (Covidien) provides a continuous bipolar waveform with an integrated cutting mechanism. GyrusPK (Gyrus ACMI) provides a pulsed bipolar waveform that allows tissue and device tip cooling during the energy-off phase, but lacks cutting capability. Enseal (Ethicon) has nano-sized conductive particles that channel energy and control temperature between the jaws. Like LigaSure, it is multifunctional with an I-Blade™ for cutting sealed tissue.
Harmonic devices have a piezoelectric crystal in the phone that converts electrical energy into ultrasonic energy. This energy is delivered to movable blades at the tip of the instrument, causing them to vibrate at a frequency of 55,000 Hz. The tip of the device is mechanically cut with some degree of collateral thermal coagulation for hemostasis. There is no active current in the tissue. Harmonic devices have the advantage of being cooler (<80°C) compared to other energy devices, thus reducing heat dissipation and reducing charring. In less dense tissues, intercellular water evaporates at lower temperatures (<80°C) due to mechanical vibrations, resulting in a "cavitation effect" that can aid dissection by separating tissue layers. They are FDA approved for container closures <5 mm. While harmonic devices operate at low temperatures, the active blades of the device get very hot and can stay there for a while. Care should be taken not to touch vital structures with the jaws of the device for a few seconds after activation.
