Small Animal Laparoscopy and Thoracoscopy. Группа авторов

plastic sleeve is cut, allowing 1–2 cm of excess to be folded into the incision. The soft plastic trocar cap is then firmly fitted to the outer ring. The insufflator tubing is then attached, and the abdomen is insufflated to 8–10 mmHg with carbon dioxide using a pressure‐regulating mechanical insufflator. Advantages to using this device are similar to those of the other wound retractor devices: the wound retractor sleeve is able to accommodate a wide range of body wall thicknesses, up to 10 cm, and the soft outer cap can be removed and reattached repeatedly during the procedure to allow tissue extraction without compromising the ability to reinsufflate the abdomen.

      Insertion Technique of Standard Trocars for Single‐Port Entry

       Single‐Port Access Technique (see Figure 6.2, Video 6.4).

      A 1.5‐ to 2‐cm skin incision is made on the ventral midline in the region of the umbilicus. Using the Hasson abdominal access technique, a 5‐mm blunt laparoscopic low‐profile trocar–cannula assembly is inserted into the abdomen. The abdomen is insufflated using a pressure‐regulating mechanical insufflator to an intraabdominal pressure between 9 and 12 mmHg. After brief abdominal exploration with a 30° telescope, two additional very‐low‐profile 5‐mm trocar–cannula assemblies are then inserted in a triangular pattern adjacent to the initial port. For the second and third low‐profile trocar–cannula insertions, the abdomen is partially desufflated to approximately 6–8 mmHg to facilitate mobilization of the skin and soft tissue associated with the initial skin incision and to enable a small soft tissue flap to be created, which allows for tunneling of the ports adjacent to the initial trocar. Using minimal blunt dissection, a tunnel is undermined 1–2 cm laterally and caudally on either side of the initial 5‐mm trocar–cannula assembly using a Kelly hemostat. Through those tunneled paths, the two low‐profile trocar–cannula assemblies are inserted through the abdominal wall into the peritoneal cavity using the sharp trocars under optical visualization. The three trocars are arranged in a deliberate triangular arrangement that causes the skin to stretch in a lateral direction. This arrangement enables each low‐profile cannula to enter the abdomen through separate facial openings but enters through the same 2‐cm skin incision. Advantages with this entry method rely on the fact that existing standard metal and reusable trocar–cannula assemblies can be used, avoiding the cost associated with purchasing disposable equipment.

Innovative Adaptations of Existing Equipment

Wound Retractor with Latex Glove and Finger Ports (Figure 6.6)

A 2‐ to 3‐cm mini‐laparotomy incision is created in advance for insertion of the port. The inner ring of a 360° atraumatic wound retraction device (Alexis Wound Retractor; Applied Medical, or SurgiSleeve Wound Protector, Covidien) is first inserted through the mini‐laparotomy incision (Figure 6.7). The outer ring of the wound retractor is then rolled until it reaches the level of the skin, causing the retractor sheath to be pulled taut. The tips of the fingers of a sterile latex glove are cut to just allow a 5‐ to 10‐mm trocar–cannula assembly to be inserted. Suture or rubber bands created from strips cut from the surgical glove finger are tied securely around the trocar–cannula assembly at the junction of the latex fingertip and the port. The wrist portion of the glove is then stretched over the external ring of the wound retractor. The insufflator tubing is then attached to any of the finger port Luer‐lock fittings, and then insufflation of carbon dioxide to an intraabdominal pressure of 8–10 mmHg is delivered using a pressure‐regulating mechanical insufflator. All five fingers can be used as ports of entry if necessary [36]. This technique was recently published for the use in dogs undergoing ovariohysterectomy [64]. The wound retractor can also be used with a laparoscopic cap designed for specimen extraction (Figure 6.8; Alexis Laparoscopic System with Kii Fios First Entry, Applied Medical). Additional portals can be added through the laparoscopic cap with the aid of a 6‐mm punch biopsy for 6.5‐mm portals. Leakage of CO₂ may result from too large or too small defects in the cap, the latter due to cracking of the cap when inserting the cannula through an insufficiently sized defect.

Figure 6.6 A wound retractor with latex glove and finger ports can be used as an inexpensive single‐port device.

Figure 6.7 This wound retractor (Alexis; Applied Medical, Rancho Santa Margarita, CA) provides a protected retracted access incision through which organs can be exteriorized.

      Instrumentation

      Conventional multiport laparoscopy is governed by the rule of triangulation such that a view is established in tandem with the simultaneously working extension of the human hand by means of the instruments [3]. Because the single‐port platform follows the premise that all instruments enter the abdomen at the same site, one is forced to challenge the laws of traditional instrument triangulation. The single‐port platform creates significant physical and ergonomic constraints that make traditional procedures more difficult to learn and perform compared with traditional laparoscopic surgery. The proximity and parallel trajectory of the telescope and operating instruments placed through the single‐site led to the inevitable instrument and cannula collision, which ultimately interferes with smooth movements and makes the procedure more demanding than standard multiport laparoscopy.

Figure 6.8 The wound retractor in figure 11 can be used with a laparoscopic cap for insufflation

      Source: Courtesy Boel Fransson Washington State University.

      In trying to overcome some of the technical difficulties associated with single‐port surgery, bent and articulating instruments have been developed to reproduce the triangulation that is experienced with conventional multiport laparoscopy and to limit some of the stated difficulties associated with using standard rigid instrumentation in single‐port surgery [29].

However, it should be noted that single‐port surgery could successfully be performed using rigid instrumentation. An extensive body of literature exists describing single‐port procedures completed by means of standard rigid laparoscopic instruments in both humans and veterinary patients. An array of articulating and double pre‐bent laparoscopic instruments have been developed and marketed specifically for the single‐port platform in an effort to correct the difficulties resulting from the loss of triangulation. Bent or coaxial deviating instruments are in a fixed position and were designed to be offset from the straight axis of a standard instrument, enabling the surgeon to have internal and external working space [65–70]. The curved design provides acceptable intracorporeal triangulation and good ergonomic positioning for the hands (Figure 6.9). The articulating instruments have a design that mimics the movements of a surgeon's wrist and have a distal tip that can deflect relative to their shaft, offering seven degrees of freedom of movement [3]. Many