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The Latest in Blood Vessel Cutting and Sealing
One surgeon's thoughts on the latest modalities, important design features and safeguards to consider when reviewing today's options.
Steven Schwaitzberg
Publish Date: April 3, 2008   |  Tags:   Patient Safety

Many devices cut and seal blood vessels during surgery — from scissors and clips to instruments based on the latest ultrasonic, bipolar and thermal cautery modalities. As these tools are constantly evolving to accommodate new surgical techniques and improve patient outcomes, here's a review to keep you up to date.

Setting the mode
While surgeons have been using scalpels, clips and sutures for blood vessel cutting and sealing for a century, devices based on three advanced modalities have been introduced to improve clinical outcomes, decrease procedure times and improve hemostasis: bipolar, ultrasonic and thermal cautery.

Bipolar electrosurgery. This modality was one of the first advanced modalities brought to market to enhance blood vessel cutting and sealing procedures. In bipolar electrosurgery, the two tips of the device typically perform both the active electrode and return electrode functions, with both functions performed at essentially the same location on the patient.

Bipolar electrosurgical generators are able to produce a variety of electrical waveforms. Using an intermittent waveform lets the device generate less heat and produce a coagulum instead of tissue vaporization. The surgeon can create a seal using a constant, high-heat waveform combined with the application of pressure. Often, devices based on the bipolar modality employ a sharp blade or knife to facilitate cutting of the tissue or vessel.

An important innovation in bipolar electrosurgery is the addition of a feature that measures the impedance of the tissue during the sealing process. When the tissue is adequately sealed, this capability sends a signal to reduce or stop additional current flow to the device and alerts the surgeon that the vessel is sealed and can be cut safely.

Devices based on bipolar electrocautery typically feature a large radiofrequency (RF) generator, a handheld device and a power cord. Sealing energy controlled by hand activation might be more desirable than a device controlled by a foot pedal. A hand-activated device lets surgeons work on a stepstool for better viewing of the surgical site. It's also easy to pass such devices across the table to an assisting surgeon.

Ultrasonic technology. Ultrasonic refers to the technology by which high-frequency mechanical vibrations are used to heat tissue. The first device based on the ultrasonic modality was a ball-shaped design that was pressed against tissue. This evolved into the open, two-jaw design that is widely recognized today.

Ultrasonic devices have a fixed-bladejaw and a pivoting jaw. When the device is activated, high-frequency mechanical vibrations cause the fixed blade to rapidly oscillate. When tissue is grasped between the oscillating blade and the opposing jaw, mechanical friction causes heat. This generated heat is employed to seal and cut the tissue.

Devices based on ultrasonic energy typically feature an ultrasonic generator, ultrasonic transducer handpiece, a footswitch, and a variety of endoscopic and open instruments.

Thermal cautery. Devices based on the thermal cautery modality can take many forms: forceps, shears or articulating devices. Only direct heat and pressure are used to achieve sealing and cutting.

The active part of the device is comprised of resistive heating elements powered by low voltage direct current. The heating elements are combined with a thermally insulating backing, which isolates the heat to a narrow profile and confines heat to a localized area. This creates a graded thermal profile with a narrow, high-temperature cutting zone and a lower temperature-coagulating zone on either side, letting the device simultaneously seal and divide tissue.

Because thermal cautery devices use low-voltage direct current, and no electrical current is required to pass through the patient, they can be integrated onto many other platforms, such as articulating laparoscopic devices. Devices based on thermal cautery typically feature a disposable forceps or shear and a lightweight, compact power supply.

Safe and effective
Surgeons are demanding new technologies that reduce procedure times, create reliable seals and further minimize the risk for collateral damage, factors which help to improve clinical outcomes. Many issues are paramount when considering a cut-and-seal device, including:

Reliability. First consider the device's ability to effectively and efficiently cut and seal vessels of various sizes. No device is 100 percent reliable, but as sealing and cutting modalities evolve, so does the reliability. The non-sealing rate for all of the modalities mentioned above is low, but some present other challenges related to equipment failure. None of the technologies are perfect, and bleeding will occur regardless of the type of device and modality used. Some reports claim a seal failure rate as high as 9 percent. In practice, that figure likely doesn't exceed 4 percent.

To increase the likelihood of good reliability, choose the simplest device to meet your needs. The fewer the number of parts and components involved, the less complex the system and the lower the risk of malfunction or operator error.

Another way to increase reliability is to choose a device that was designed specifically for the intended procedure. With so many devices on the market today, there are plenty of options to meet your needs (devices for small vs. large vessels or cardiac vs. colorectal procedures, to name a few).

Safety. While the modalities highlighted in this article are relatively safe, each presents its own potential safety issues. One of the greatest concerns is unintended collateral damage to surrounding tissue structures.

To enhance the safety of your procedures, choose devices that require the least amount of energy delivered to the patient and provide the highest level of control. Built-in safety features to prevent inadvertent cutting during a procedure can further increase safety by decreasing the risk of operator error. Some devices require a high level of user technique, increasing the likelihood that an inadvertent slip of the hand might direct energy or blades to untargeted areas of the vessel. Try to find handpieces that rely on minimal user influence to be effective. Devices that produce less smoke and splatter are also advantageous as these can reduce visualization errors and instrument exchange.

Ease of setup and use. To improve efficiency in the OR and further decrease the risk of operator error, choose a device that's easy to set up, break down and store. Your staff shouldn't have to scramble to locate and assemble missing parts and components before a procedure or navigate around an OR full of tangled cords and cables. Simplicity is key — choose a system that is straightforward to assemble and operate. Plug-and-go devices will give your staff a break during room turnovers.

Compatible and versatile. These points relate to the reliability, safety and ease of use mentioned above. Some devices are not compatible with implantable pacemakers, nerve monitors and other instrumentation. Before introducing a cutting-and-sealing device into your OR, conduct some research to ensure that the system is compatible with the other equipment used in your procedures to avoid potential complications, including stray electrodes.

If possible, choose a system that is versatile and can be used across a broad range of procedures. If you can use one modality for different forms, the staff will be more comfortable with the technology, setup, mode of operation and safety features. Having multiple devices that share the same power unit can also reduce costs.

Cost. Administrators face increasing pressure to maximize efficiency and revenue. Surgeons want to improve patient care without engaging in a fight to get new technology through the door. To please both parties, choose a cutting-and-sealing modality that requires minimal capital investment and one that features a reliable and versatile platform that you can deploy during various types of procedures.

The costs of handpieces typically range between $250 and $350. Don't settle for a handpiece that isn't ergonomic or cost-effective. They do exist. Manufacturers are working to lower the initial costs of the disposables used with the handpieces (electrodes, for example). Some reusable handpieces are also on the market, which may lower your costs per case.

Down the road
Advances over the last few years have included the introduction of articulating and robotic platforms and natural orifice surgery, in which you perform surgery by inserting a camera and tiny instruments through natural openings — the mouth, rectum or vagina. With articulating devices, surgeons can reduce the number of instrument exchanges during endoscopic procedures and allow for single-incision surgeries. Natural orifice surgery lets you perform procedures with minimal scarring and discomfort to the patient (see "Points of Entry," February, page 26).

Adaptable technology has a better chance for application in natural orifice procedures. The effectiveness of cutting-and-sealing devices will depend on the basic physics of the energy source.

To succeed in the burgeoning natural orifice specialty, the cutting-and-sealing energy will have to be carried to the end of devices that vary in size and shape. Based on that design reality, ultrasonic technology has the length specifications most suitable for use in the development of effective natural orifice instrumentation.

As new techniques and devices are developed, surgeons still need to evaluate the technologies based on key considerations such as reliability, safety, compatibility and cost to both enhance case outcomes and comply with today's challenging healthcare business environment.