invasive instrumentation for use in both human and veterinary endoscopic surgery. In this section, we will focus on instruments most commonly used in small animal laparoscopic and thoracoscopic procedures. We will also discuss some instruments used in human surgery with potential for veterinary application.
Instruments for minimally invasive surgery (MIS) consist of the same basic parts as traditional instruments (Figure 4.1). Their shafts are long and thin to allow them to pass through an instrument portal into a body cavity. Some shafts are insulated to allow for monopolar or bipolar electrosurgical applications. If using an insulated shaft with electrosurgery, it is very important to regularly inspect the shafts for cracks or wear. Defects in the shaft insulation may lead to inadvertent electrical burns to other tissues. Shafts come in straight, articulating, and roticulating designs. Articulating shafts bend in a single plane, whereas roticulating shafts are able to rotate and bend in multiple planes, more accurately mimicking the motion of the human wrist. The choice of shaft configuration used depends on the intended approach, the procedure to be performed, and the surgeon's level of experience and preference. Straight instruments are the basic instruments for MIS and are most commonly used by novice surgeons and in multiple‐port surgery. While they can be used in single‐port approaches, difficulty in attaining optimal instrument positioning and instrument clashing are common problems encountered when using straight instruments through a single port. Articulating and, later, roticulating shafts were developed to allow for better tissue visualization, more accurate instrument angles in relation to the target tissues, and less conflict between instruments and the telescope when used in single‐port procedures. Both articulating and roticulating shafts are also beneficial in advanced, multiple port procedures, such as cholecystectomy, where the articulating/roticulating dissectors allow for a more correct angle to dissect around the cystic duct. Articulating and roticulating shafts are available for a variety of instruments including dissectors, graspers, scissors, and staplers. A steep learning curve has been reported for performing single‐port procedures using articulating or roticulating instruments. When starting to use these instruments, it is recommended to become comfortable using the articulating shafts before progressing to operating with the roticulating shafts. Recently, some manufacturers have discontinued articulating shafts and solely offer roticulating instruments.
Figure 4.1 Endoscopic surgical instrument components. (A). Working end (jaws of the instrument). (B). Shaft. (C). Handles.
Source: © 2014 Photo courtesy of KARL STORZ SE & CO, KG.
Figure 4.2 Minimally invasive surgical instrument handle types (from left to right): nonlocking (nonratcheted) rings, locking rings with a hemostat ratchet, locking rings with a Manhes ratchet, and straight handle with ratchet for certain endoscopic needle holders.
Source: © 2014 Photo courtesy of KARL STORZ SE & CO, KG.
Most instruments have either ratcheted or nonratcheted ringed handles (Figure 4.2). Ratcheted handles lock via one of several ratchet mechanisms, depending on the manufacturer. Laparoscopic needle holders, however, have a straight handle design with either a hemostat style or a disengageable ratchet locking mechanism to allow for easier manipulation of suture and needle within a body cavity. Ringed handles are held in the same tripod manner as traditional instruments, with the thumb and ring finger in the rings and the index finger stabilizing the shaft. A dial that is easily reached by the index finger allows for 360° rotation of the shaft around its longitudinal axis. Shaft rotation allows for optimal positioning of the instrument jaws when working within a confined space. Handles intended for use with insulated shafts for monopolar or bipolar electrocoagulation also have a high‐frequency connector for application of an electrical current from an electrosurgical generator. Monopolar and bipolar handles and shafts are distinct from one another and cannot be interchanged.
Instrument jaws come in a variety of shapes and sizes according to their intended function as graspers, dissectors, scissors, retractors, biopsy forceps, or needle holders. The working end of an endoscopic instrument may have a single‐ or double‐action mechanism (Figure 4.3). With single‐action instruments, one side of the jaw is hinged so that it opens and closes against a stationary opposing jaw. Double‐action working ends are hinged in both jaws, allowing both sides to open and close and resulting in a wider and often stronger grasp.
Figure 4.3 Examples of a single‐action jaw mechanism (left) and a double‐action jaw mechanism (right).
Source: © 2014 Photo courtesy of KARL STORZ SE & CO, KG.
Both disposable, single‐use instruments and reusable instruments are available. For veterinary practice, reusable instruments are more economical. Early instrument designs may be more difficult to adequately clean and sterilize than more current designs, a fact that should be considered when purchasing laparoscopic equipment. Instruments are available as single‐piece or as modular units, depending on the manufacturer, and can be made of high‐grade plastic or stainless steel. There are benefits for each design type. Single‐piece instruments avoid the possibility of mismatching components; however, as mentioned previously, older models may be difficult to decontaminate. Newer designs have portals that allow for cleaning of the shaft lumen. They also avoid nooks and crevices that are difficult to reach, making cleaning and decontamination easier. Modular units allow for the use of a variety of shafts and working ends with the same handles. Additionally, individual components are easier to thoroughly clean, can be sterilized separately or as a complete instrument, and can be replaced if they break rather than replacing the entire instrument.
Regular endoscopic instruments come in 5‐ and 10 mm diameters. For most small animal applications, 5‐mm instruments are adequate. Common exceptions are the use of 10‐mm Babcock or Duval forceps for grasping thicker tissues such as the stomach wall. Mini‐laparoscopic instrumentation is now available for small dogs and cats weighing less than 10 kg. These come in 2‐, 2.3‐, and 3 mm diameter sizes, depending on the manufacturer. The available shaft length depends on the instrument diameter and should be chosen based on patient size, with shorter shafts used for small patients and longer shafts for large or obese patients. Using a shaft that is either too long or too short for the patient can be awkward for the operator and can inhibit the ability to reach tissues inside the body cavity. Short and long shaft lengths vary by manufacturer but are similar. In general, 5‐ and 10‐mm instruments range from 33 to 36 cm for the short length and from 43 to 45 cm for the long length. Mini‐laparoscopy instruments range from 20 to 30 cm in length.
Forceps
Laparoscopic forceps can be divided into three categories: grasping forceps, dissecting forceps, and biopsy forceps. Just as in open surgery, the type of forceps selected will depend on its intended use. The jaws of laparoscopic forceps can be crushing or noncrushing, straight or curved, and long
