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Cutting Edge Choices
Innovations in cutting and sealing technologies are reshaping the field.
David Bernard
Publish Date: February 21, 2014
instrument decisions DETERMINING FACTORS Surgeons base their instrument decisions on vessel size, risk of thermal spread and quality of seal.

Is it time for your surgeons to reconsider their favored cutting and sealing devices? They can now choose from among several methods to do the job: advanced bipolar, ultrasonic, thermal tissue fusion and plasma devices. Read on for an overview of recent innovations to these energy-based essentials and insights on what makes them more efficient and safer options.

Bipolar and ultrasonic: variations on a theme
Advanced bipolar devices employ the tissue's resistance to electrical current to generate heat within the tissue, which is used to dissect and coagulate it. The jaws of a device's forceps are the active and return electrodes, between which electrical current in the form of radiofrequency energy passes. Because they're on a single instrument, the electricity flows only through the limited area of tissue grasped by the device's jaws to initiate the cutting and sealing.

With ultrasonic devices, also commonly known as harmonic scalpels, the cutting and sealing effect is produced by mechanical energy. An electrical source unit is connected to a piezoceramic transducer (similar to those found in dental plaque removers or ophthalmic cataract phacoemulsifiers) in a forceps handpiece. The transducer sends high-frequency vibrations to the grasping jaws, which heats the tissue between them to make the seal.

One of the chief risks involved in the use of energy-based cutting and sealing devices is thermal spread. In this complication, the heat and desiccation applied to cut tissue and seal a vessel spread farther than necessary and injure adjacent tissue. It only takes a couple of seconds, and may only affect a couple of millimeters, but the resulting tissue breakdown can pose potentially fatal infection risks. "It's something we worry quite a bit about," says William L. Barrett, MD, a general surgeon at CaroMont Surgical Associates in Gastonia, N.C.

Dr. Barrett says that improvements to the temperature regulation system in the ultrasonic cutting and sealing technology he relies on have improved the accuracy of its energy delivery and curbed high temperature spikes to mitigate the risk of thermal spread.

laparoscopic surgery INSIDE JOB Efficient laparoscopic surgery depends on energy-based cutting and sealing technology.

Safety's not the only improvement that the product category has seen, he says. Redesigned jaws lend an additional measure of efficiency. Devices featuring larger jaws let users seal larger vessels during open surgeries, and articulation at the device's distal end gives laparoscopic surgeons a little more reach. The resulting longer holds on tissue, however, have necessitated the development of handpieces that signal users with audible tones or other warnings to ensure safe handling.

One manufacturer's recent integration of advanced bipolar and ultrasonic cutting and sealing energies into a single handpiece has already gained a significant following due to the efficiency and versatility it offers, notes Stephen Cohen, MD, MBA, FACS, FASCRS, who practices at Atlanta (Ga.) Colon and Rectal Surgery and chairs the department of surgery at Southern Regional Medical Center in Riverdale, Ga. The device couples the 2 modalities to simultaneously seal and cut with minimal thermal spread, and lets users switch between them when a surgical procedure calls for it.

Thermal fusion and plasma: advantageous approaches
A technology known as thermal tissue fusion applies direct thermal energy and pressure to vessels and tissue bundles to quickly and reliably seal, dissect and coagulate in open or laparoscopic cases while avoiding some of the drawbacks of advanced bipolar and ultrasonic methods, according to the manufacturer of one such device.

A system of feedback between the handpiece and the energy source lets the temperature be controlled and the cutting and sealing energy be delivered more precisely. This response helps to minimize the risk of thermal spread. The speed of the energy's effects also limits injury to adjacent tissue, and reduces fatigue in the ergonomically taxed hands of laparoscopic surgeons. As thermal tissue fusion works bladelessly, its components will not dull or jam or become obstructed by remnants of charred tissue.

In Dr. Cohen's view, the next wave of cutting and sealing will be driven by plasma. "It's a very cool technology," he says, whose heat comes from an inert gas electrically excited into a plasma state. The device releases not only thermal energy for cutting, vaporization and coagulation, but also light energy for visibility in the laparoscopic surgical site. "The energy is focused where it hits the tissue," he says, and disperses quickly, so there's little risk of thermal injury to the surrounding tissue. In highly vascularized anatomy, that's a plus.

Cut and Seal With Caution

vascularized anatomy SEE A WAY THROUGH In highly vascularized anatomy, the rapidity of cutting and sealing energies can reduce bleeding and improve post-op outcomes.

It's not an overstatement to argue that energy-based cutting and sealing devices revolutionized the performance and outcomes of open and laparoscopic abdominal surgeries. "That area is extremely vascular, and tends to bleed a lot when we cut out tissue," says Stephen Cohen, MD, MBA, FACS, FASCRS, a general surgeon who operates at Atlanta (Ga.) Colon and Rectal Surgery and chairs the department of surgery at Southern Regional Medical Center in Riverdale, Ga. "We have a vested interest not only in operating and removing tissue, but also in decreasing blood loss and pain."

"With the advent of new technology, it is crucial to understand the mechanics of how instruments work to fully be able to utilize them and prevent injury," wrote Resad Pasic, MD, PhD, in an article on the science and safety of laparoscopic cutting and sealing devices in a 2008 issue of the journal Surgical Technology International.

Dr. Pasic, a professor of obstetrics, gynecology and women's health at the University of Louisville School of Medicine in Kentucky, has recommended that physicians and their assistants undergo in-service training sessions — led by manufacturers' representatives — when trialing or implementing new energy-based instruments to ensure that they don't "start cutting and burning without a full understanding of the mechanics" of the seemingly accessible and easy-to-use devices.

It doesn't take an advanced degree in physics to understand one of their major handling risks, though. "You've always got to be aware that the device is hot," and remains so after use, says William L. Barrett, MD, a general surgeon at CaroMont Surgical Associates in Gastonia, N.C. Laparoscopic tools are an extension of a physician's hand, but these devices should not be used to sweep aside tissue. "If a hot harmonic scalpel touches bowel, you won't see the thermal effect immediately, but once you've done it, the damage is done."

He also points out that different energies are likely to create different amounts of surgical smoke or vapor as by-products of their cutting and sealing effects, which may impair a laparoscopic surgeon's view of the site, so suction or continuous evacuation systems should be in use when energies are.

Exercise caution outside of the surgical site as well as inside it. The hot jaws of recently used devices should not make contact with thin, combustible surgical drapes, but should instead be cooled on a damp sponge or gauze.

That type of risk isn't so much a negative reflection on the device as it is on the user, says Dr. Cohen. All the same, it shows the need to rethink practices when adapting new techniques. "With any new technology comes challenges," he says. "And we're all looking to do the safest thing."

— David Bernard

Choice and capability
Given the available options and innovations, what factors should surgeons consider to best serve their cutting and sealing needs? "In my mind, the choice depends on the size of the vessels you're dealing with," says Dr. Barrett. "If they're larger vessels, a bipolar device. If they're smaller, ultrasonic."

But safety is another important consideration, he says, adding, "What kind of tissue is around the site? The small bowel is a big risk area for thermal spread. Which device has the best control over energy delivery and temperature regulation?"

"Every technology has its own nuances," says Dr. Cohen, but he notes it's not easy to compare and differentiate them in terms of their surgical outcomes. "What outcomes do you want? There are many studies on energy use in hemorrhoid surgery, for instance. A literature search on any of these instruments will show you the feasibility with which it can be done." But a patient's post-op pain is a subjective measure, no matter which method you use, and there's a wide range of inter-related factors to consider in assessing a surgery's success.

"It all depends on the value a technology adds to a case. I see value in, how quickly can I seal the vessel? Does it stand the test of time, which is to say 7 to 10 days?" says Dr. Cohen. A quality seal that can resist post-op bleeding without requiring suture in addition to the use of energy means in many cases less pain. It also cuts out the cost of suture from a case. "Then I can increase the value to everyone involved, the physician, patient and facility. I like looking at new technology if it's quicker, if it doesn't heat up as much, if it's easier to use."

Not everyone's an early adopter — some users need more evidence of value than others — but physicians are willing to change. "The way we do surgery now is very different from the way we did it 25 years ago, and it will be different 25 years from now," says Dr. Cohen, recalling a conference he attended in 1990, at which he saw a senior surgeon storm out of a presentation, outraged at the suggestion that laparoscopy was a suitable option for gall bladder removal. "Now that's standard practice."