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 of these instruments also offer axial 360° rotation for tip orientation similar to conventional rigid instruments. All of the articulating instruments can be introduced in both single‐port devices and conventional rigid trocar–cannula assemblies. The double pre‐bent instruments are intended to mimic triangulation through a curved design of both ends of the instrument shaft, which leads to antipodal directions of the tips and handles when the instruments are held in parallel [71]. The double‐bent instruments can only be used with soft, flexible, or specifically designed entry devices for bent instruments because the bends in these instruments prevent their introduction into a rigid trocar–cannula assembly.
Figure 6.9 Coaxial instruments used through single‐port devices can obviate some of the disadvantages encountered when the ability to triangulate is compromised.
Source: Courtesy of J. Brad Case.
Figure 6.10 A right‐angle adaptor placed onto the connection between the light cable and telescope can reduce interference between the light cable and instruments during single‐port surgery.
Optics
With the close proximity of the telescopes and instruments in single‐port surgery, adjustments are required to create space both internally and externally to avoid instrument and optic interference. The easiest way to avoid optics and instrument clashing during the procedure is the use of an angled telescope. The most common telescope used for single‐port laparoscopy in veterinary medicine is a telescope with a 30° angle. To further reduce the external clashing of instruments with the light cable, a right‐angle adaptor for the light cable can be used (Figure 6.10). Recently, the development of advanced laparoscopes geared specifically for single‐port surgery has emerged. A variety of deflectable telescopes with different mechanical design properties have recently been shown to be effective. One design involves a traditional fixed‐rod design that contains a rotating lens at the distal end (EndoCAMeleon, Karl Storz Endoscopy), or alternatively a design that uses the “chip on the tip” concept by placing an image processor at the distal tip of an articulating laparoscope (EndoEye, Olympus; Idealeye Stryker, Kalamazoo, MI) [72]. During veterinary single‐port surgery, it has been shown that using either a 30° telescope or an advanced deflecting optic enables the telescope's camera head and tip to be directed away from the other instruments during the procedure, improving working space while simultaneously maintaining excellent visualization.
Conclusion
The single‐port platform is a recent innovation in minimally invasive surgery. This platform may represent the next step forward in minimally invasive techniques. Early reports in the veterinary literature have shown this access method as a feasible and potentially more attractive approach for many common veterinary procedures. The focus of all new surgical techniques should be feasibility, safety, and efficacy, and they should provide a clinical advantage over other existing methods. Further studies are needed to determine if this platform for surgery can be considered a comparable alternative to multiport laparoscopy. Continually pursuing these types of research initiatives will help to drive emerging minimally invasive techniques and technology that ultimately benefits both human and veterinary patients alike.
References
1 1. Darzi, A. and Munz, Y. (2004). The impact of minimally invasive surgical techniques. Annu. Rev. Med. 55: 223–237.
2 2. Keus, F., de Jong, J., Gooszen, H.G. et al. (2006). Laparoscopic versus open cholecystectomy for patients with symptomatic cholecystolithiasis. Cochrane Database Syst. Rev. 4: CD006229.
3 3. Kommu, S.S. and Rane, A. (2009). Devices for laparoendoscopic single‐site surgery in urology. Expert Rev. Med. Devices 6: 95–103.
4 4. Gill, I.S. (2010). Consensus statement of the consortium for laparoendoscopic single‐site surgery. Surg. Endosc. 24 (4): 262–268.
5 5. Islam, A., Castellvi, A.O., Tesfay, S.T. et al. (2011). Early surgeon impressions and technical difficulty associated with laparoendoscopic single‐site surgery: a society of American gastrointestinal and endoscopic surgeons learning center study. Surg. Endosc. 8: 2597–2603. (previous 4).
6 6. Galvao Neto, M., Ramos, A., and Campos, J. (2009). Single port laparoscopic access surgery. Gastrointest. Endosc. 11: 84–93.
7 7. Qiu, J., Yuan, H., Chen, S. et al. (2013). Single‐port versus conventional multiport laparoscopic cholecystectomy: a meta‐analysis of randomized controlled trials and nonrandomized studies. J. Laparoendosc. Adv. Surg. Tech. 23: 815–831.
8 8. Liu, X., Yang, W.H., Jiao, Z.G. et al. (2019). Systematic review of comparing single‐incision versus conventional laparoscopic right hemicolectomy for right colon cancer. World J. Surg. Oncol. 17: 179. https://doi.org/10.1186/s12957‐019‐1721‐6.
