Small Animal Laparoscopy and Thoracoscopy. Группа авторов

6.3).

Principles of Single‐Port Surgery

The principles of single‐port surgery are very similar to those of conventional multiport laparoscopy, although differences exist associated with the way triangulation is achieved. Having one point of entry inherently prevents the traditional principles of instrument triangulation. The close proximity of the instruments and optics, both intra‐abdominal and extra‐abdominal, causes the surgeon to perform the procedure with suboptimal working space intra‐abdominally. This ultimately causes increased technical complexity for any procedures because of inadequate triangulation, a compromised field of view, inadequate exposure, and frequent instrument collisions, which all occur as a result of the common entry point for the camera and instruments [29]. Single‐port laparoscopy has been able to somewhat overcome this lack of triangulation by using angled optical telescopes, crossing instruments, or bent and articulating instruments. This novel arrangement of both the optics and instruments creates more internal and external working space, allowing for some triangulation that prevents instrument crowding. Although standard instruments can be used for single‐port surgery, numerous instruments and devices have been developed to simplify and make single‐port surgery more user friendly.

Figure 6.3 The SILS (single‐incision laparoscopic surgery) port (Covidien, Mansfield, MA) allows the placement of three cannulae and has a separate CO₂ insufflation port.

Access in Single‐Port Surgery

      The devices and equipment used for single‐port surgery can be broadly classified as: (i) specifically manufactured devices for single‐port surgery, (ii) standard instruments and trocar–cannula assemblies used for conventional laparoscopy inserted through one skin incision, or (iii) innovative adoptions of existing equipment not primarily intended for laparoscopy.

      Insertion Techniques for Specifically Manufactured Single‐Port Devices

      GelPOINT Access System (Applied Medical Inc., Rancho Santa Margarita, CA)

       A 2‐ to 7‐cm mini‐laparotomy incision is created in advance for insertion of the port (Video 6.1). This single‐port device consists of a wound retractor, GelSeal cap, and four 5‐ to 10‐mm cannulae. The wound retractor portion of this port provides 360° atraumatic retraction of an abdominal incision 2–7 cm in length. The wound retractor portion is required to be inserted initially by passing the inner flexible ring through the abdominal incision. The outer ring is then rolled until it reaches the incision causing radial retraction. The cannulae are inserted through the GelSeal cap, and the GelSeal cap is then fitted to the outer ring of the wound retractor. The insufflator tubing is then attached, and the abdomen is insufflated to 8–10 mmHg with carbon dioxide using a pressure‐regulating mechanical insufflator. There are several advantages to using this device: the wound retractor sleeve is able to accommodate the widest range of body wall thicknesses compared with other single‐port devices; the wound retractor portion can accommodate a 7‐cm incision, which can enable large tissue removal; and the GelSeal cap can be removed and reattached repeatedly during the procedure without compromising the ability to re‐insufflate the abdomen.

SILS Port (Covidien; Figures 6.3 and 6.4)

A 2‐ to 3‐cm mini‐laparotomy is created in advance for insertion of the port. To insert this single‐port device, a small amount of sterile lubricant is applied to its soft base (Video 6.2). The port is inserted into its 2‐ to 3‐cm abdominal incision by clamping two curved Rochester‐carmalt forceps at the base in a staggered fashion. Varying techniques have been described for insertion into the incision: it can be performed without abdominal wall countertraction or with a form of countertraction such as grasping the facial edges with two large rat‐toothed tissue forceps, Army‐Navy retractors, or stay sutures. Regardless of traction, the tips of the Rochester‐carmalts are directed into the incision in a cranial direction toward the diaphragm or away from any underlying viscera. When the base is seeded within the incision, the clamps are then released to allow the bottom portion of the port to expand and fit snugly within the incision. Three 5‐mm cannulae (supplied with the port) are then partially inserted into the three inner cylinders with the aid of a 5‐mm blunt obturator. The SILS port is also supplied with a 12‐ to 15‐mm trocar–cannula assembly to allow larger instruments to be inserted with two other 5‐mm cannulae. The heights of the cannulae are staggered to minimize cannula contact (Figure 6.5). Insufflator tubing is then attached, and the abdomen is insufflated to 8–10 mmHg with carbon dioxide using a pressure‐regulating mechanical insufflator. Once insufflation is complete, the three canulae can then be inserted deeper into the port. The multitrocar port can be positioned to have the three 5‐mm cannulae at the 12, 4, and 8 o’clock positions relative to the surgical site, although any arrangement is possible. Advantages of this port include the relative ease of insertion and reinsertion during a procedure and its ability to fit snugly within the incision, preventing loss of pneumoperitoneum.

Despite being sold as single‐use instruments, it is not uncommon to reuse various minimally invasive surgery devices in veterinary medicine for economic reasons. Multiple studies have been conducted to test the reusability of the SILS devices [61–63]. Results indicate that the ports can be decontaminated and sterilized by ethylene oxide and hydrogen peroxide vapor for repeated use. In one study [62], the foam component was found to have positive light growth after eight uses. The reuse of the SILS ports appears to carry a low risk of infection to the patient; however, the mechanical stability of the ports after reuse has yet to be widely tested.

Figure 6.4 With the SILS (single‐incision laparoscopic surgery) device (Karl Storz Endoscopy, Goleta, CA), it is recommended to stagger the cannulae to minimize interference.

Figure 6.5 With some port devices, some triangulation can still be maintained, but this varies by device.

TriPort System (Olympus)

       This single‐port device is inserted into a 1.5‐ to 2‐cm abdominal incision by directing the internal ring of the wound retractor through the incision (Video 6.3). A small amount of sterile lubricant can be applied to the inner retractor ring to aid in insertion. The inner ring is released from the supplied introducer within the incision to the abdominal cavity. The ring is then adjusted to sit just on the inside of the incision. The transparent sleeve attached to this inner ring is pulled up and away from the patient while the outer ring is simultaneously pushed down toward the incision. The inner and outer rings of this entry system are firmly pushed together while the