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Energy-based techniques to ensure hemostasis and limit damage during laparoscopy

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An experienced practitioner details the technical aspects of 3 modalities and advises an orderly protocol, rather than reflex alone, to minimize risk.


 

References

KEY POINTS
  • Inspect all vascular sites with and without insufflation before assuming hemostasis is complete.
  • In monopolar electrosurgery, electrode contact using low-voltage current leads to deeper, more effective penetration than higher-voltage current.
  • To minimize unwanted thermal damage during bipolar electrosurgery, stop current flow at the end of the visible vapor phase, apply current in a pulsatile fashion, and secure pedicles by alternating between partial desiccation and incremental cutting.
  • Since ultrasonic energy does not generate the high temperatures created by electrosurgery, it is less dependable for deep-tissue coagulation.

Compared with laparotomy, laparoscopic surgery achieves better hemostasis with less blood loss. Not only does this approach avoid an abdominal incision and the trauma associated with traction, manual manipulation, mechanical dissection, and larger tissue pedicles, but its illumination and magnification afford superior anatomical clarity, allowing the surgeon to seal a vessel before it is incised.

Still, keen surgical judgment remains critical—despite the availability of innovative electrosurgical, ultrasonic, and mechanical laparoscopic devices. Incomplete hemostasis or incision of an active vascular core can occur even with ideal application.

This article outlines the key ingredients of hemostasis during laparoscopy, focusing on the following modalities:

  • monopolar electrosurgery
  • bipolar electrosurgery
  • ultrasonic energy

An orderly protocol minimizes risk

The art of surgical hemostasis is preventing vascular trauma while leaving the least-possible collateral tissue damage. When bleeding is encountered, the surgeon’s ability to attain hemostasis using a particular modality depends largely on how well he or she understands its technical aspects. Of course, thorough knowledge of anatomy also is crucial to prevent inadvertent damage to vital structures.

Surgical hemostasis should not be driven by reflex alone. Instead, surgeons should always follow this orderly sequence of steps to minimize risk:

Identify source of bleeding. Before taking any action, make every effort to accurately determine the source of bleeding and its proximity to vital anatomy. Even in the face of active hemorrhage, you can usually identify the bleeders by combining mechanical tamponade (using the jaws of a grasper or the side of a simple metallic probe) with active hydrolavage (using an irrigator-aspirator to break up and remove blood and clots).

Protect vital structures. If the bowel, bladder, or ureter is in close proximity to the bleeder, mobilize that structure sufficiently before applying energy. You can usually protect these entities by using a combination of countertraction and incremental tissue dissection. Whenever the peritoneum is involved, a relaxing incision parallel to the structure of concern also may be useful.

This protocol mandates withholding thermal energy until an orderly sequence of anatomical triage is carried out. Whenever a vital structure cannot be adequately mobilized, make every effort to control hemorrhage by using mechanical tamponade alone for up to 5 minutes. If access to the bleeding site or vessel caliber render pressure-alone unrealistic, employ either a carefully applied thermal energy or a suture ligature. If the surgeon is uncomfortable using either of these, conversion to laparotomy may be warranted.

Inspect vascular sites. Finally, because pneumoperitoneal pressure alone can tamponade venous bleeders—as well as small arterial ones—inspect all vascular sites with and without insufflation before assuming hemostasis is complete.

Monopolar electrosurgery

With conventional electrosurgery, tissue is coagulated when an electric field is applied across it using high-frequency alternating current. Whether cutting or coagulation occurs depends on the rate and extent of thermodynamic effects (FIGURE 1).

Mechanism of coagulation. When tissue comes into contact with the surface of an activated monopolar electrode, a relatively low-current circuit is completed.

  • As the tissue is slowly heated to and maintained at temperatures above 50°C, irreversible cellular damage occurs. This is caused by deconfiguration of regulatory proteins and denaturation of cellular proteins.
  • If the tissue is heated to 100°C, cellular water completely evaporates (desiccation), localized hemostasis occurs due to contraction of blood vessels and the surrounding tissues (coagulation), and collagens convert to glucose, which creates an adhesive effect between the tissue and electrode.
  • Temperatures above 200°C cause carbonization and charring.

Select the best output voltage. Since the output voltage of “coag” current is very high (FIGURE 2), contact coagulation is generally limited to superficial layers. That is because of the accelerated buildup of tissue resistance from rapid desiccation and carbonization. Conversely, electrode contact using the lower-voltage “cut” current heats tissue more gradually, leading to deeper and more reliable penetration. Thus, both contact and coaptive coagulation with monopolar electrosurgery are more effectively performed using “cut” current.

Since superficial-appearing endometriotic implants may extend deeply into the retroperitoneal tissues, I thermally ablate these lesions using a broad-surface electrode in contact with “cut” current. In contrast, I treat superficial implants on the ovarian cortex with “coag” current to minimize unwanted thermal injury to adjacent follicular tissue.

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