How technology using different forms of energy has helped to increase patient safety and surgeon efficiency in the OR.
March 16, 2010
For years in open surgery, surgeons maintained bleeding by clamping bleeding vessels and tying them off with ligatures. Yet, the idea of using heat to stop blood flowing out of an incision can be traced back to Egyptian times, when heated stones were placed on bleeding blood vessels, says Dr. Ryan Lewis, Chief Medical Officer at Megadyne.
In 1926, a physicist by the name of William Bovie and a neurosurgeon, Dr. Harvey Cushing, worked together to develop electrosurgery—a technology using radiofrequency waves to stop bleeding in surgical procedures. The first surgery using electrosurgery was performed October 1, 1926.
Since the availability of the Bovie machine in the 1960s, surgeons have used electrosurgical devices in the OR to cauterize tissue and stop bleeding. More recent devices also encompass the ability to cut and dissect tissue.
Throughout its development, electrosurgical devices, or energy-based devices, have evolved to offer surgeons and staff different forms of energy to improve safety and efficiency in the OR.
The Energy Evolution
The first generation electrosurgery devices utilized monopolar energy, meaning the energy comes out of one tip of a device, often a pencil-like instrument. As Dr. Lewis explains, the energy enters the patient through the tip of the device and in order to exit, it must go through the patient to a grounding pad. This pad usually comes in the form of an adhesive patch put on the patient, or a pad the patient lays on in the OR. The energy goes through the patient, out through the pad and back to an electrosurgical generator to which the device is plugged into. This creates a circuit.
While using any energy-based device in the OR has a certain amount of risk to it, Dr. C. Neal Ellis, a general surgeon, colon and rectal surgeon, Professor of Surgery and Director of Surgical Research at the University of South Alabama, says first-generation monopolar cautery had safety challenges associated with the spread of energy, which could cause damage to adjacent structures not intended to be damaged. Still, he says, surgeons knew for generations the limitations of these initial electrosurgery units, and they worked well in open surgery.
“For cautery, the electrosurgery units could only cauterize a vessel up to 1 to 2 mm,” Dr. Ellis says. “We knew that and so we tied everything else. We were doing well in the days of open surgery before the laparoscope because we were able to look and know what we could cauterize and what we had to tie.”
Then, the laparoscope came along, preventing surgeons from seeing all of the vessels in the area to evaluate where electrocautery could be used.
“In the early days of laparoscopy, we were working in a three-dimensional space on a two-dimensional screen,” Dr. Ellis explains. “Sometimes we damaged things we didn’t mean to with the monopolar cautery. That spread of energy that we couldn’t see through adjacent structures was really unacceptable. A lot of patients suffered from injuries of that.”
These injuries were often the result of the spread of electricity onto surrounding tissues.
“The nerves conduct electricity better than the muscle does and better than bone, so if you’re close to a nerve, the electricity goes down the path of least resistance, which happens to be the nerve, and the nerve gets zapped,” he says. “This was particularly important in pelvic surgery where we were trying to preserve the nerves to the genitalia, the rectum, the bladder and we would damage some of these areas that we were trying to preserve.”
Dr. Ellis says surgeons would burn holes in the bowel, or cause adhesions, particularly in autonomic nerves in the pelvis because the electricity would pass through the nerve better than the muscle or blood being cauterized. Additional complications included damaging the common bile duct and causing it to stricture, and occasionally trying to cauterize a vessel that was too large.
“A vessel might look like it was only 1 to 2 mm, but when you hit it, it was 3 to 4 mm and bled all over everything,” he explains.
Today, monopolar electrosurgical instruments have progressed to become multi-functional and safer by reducing thermal spread. Some of the newer instruments have the ability to both cut and cauterize tissue, providing a surgeon with the control of a scalpel in the same instrument that can also cauterize to control bleeding.
Further, bipolar energy devices were developed to try to eliminate some of the safety issues associated with the unwanted spread of energy. According to Dr. Lewis, bipolar devices look like a pair of tweezers or forceps. The positive and negative electrodes are very close together, and the energy only travels between the two tips. Tissue to be cut or coagulated is placed between those two tips.
As Dr. Ellis explains, only a very small part of the patient actually had current passing through them with bipolar energy, but the current could still spread to either side of those to electrodes. Further, the first-generation bipolar devices provided surgeons with little control of when to stop applying the energy.
“You applied current until your eyes told you ‘that looks like that’s enough and I’ll see what happens,’” he says. “We had absolutely no control over it. What invariably happened is we applied too much current and we had charring, sticking, generated smoke and that current would spread farther than we had anticipated.”
Second-generation devices helped improve concerns of energy spread by hooking a computer up to measure the current. When the computer sensed the tissue had been effectively cauterized, it would shut off to help prevent the spread of that current.
Then, ultrasound dissectors were introduced as a new way to utilize energy in the OR without introducing electricity into the patient.
“They have very little lateral energy spread, there is no electricity going through the patient, so it doesn’t mess with pacemakers and other kinds of devices,” Dr. Ellis says. “It can handle vessels up to 4 to 5 mm safely. The ultrasound has been spectacular for a number of years. I love the ultrasound and use it when I need precision.”
Recently, third-generation instruments have been introduced to not only control the amount of current going through the patient, but to control the temperature, as well. According to Dr. Ellis, the new bipolar devices can take blood vessels up to 7 mm safely and reliably, which is useful in laparoscopic surgery where few vessels are larger than that.
Developments in energy-based surgical devices have been largely centered on improving patient safety. The ability for some devices to both cut and cauterize tissue allows surgeries to move along by saving surgeons the time it would normally take to exchange different instruments with separate functions. This saves overall OR time and minimizes the time patients spend on the OR table under anesthesia.
While many of the newer instruments also incorporate improved ergonomics allowing the devices to be operating entirely by hand, even the footswitches traditionally hooked up to the electrosurgical generator and stepped on by the surgeon to activate the device have improved to enhance safety in the OR.
According to Jimmy Logsdon of Linemaster Medical, foot pedals are used with some electrosurgical systems to minimize hand fatigue on the part of the surgeon. A safety hazard in the past has been the cord that connected the pedal to the electrosurgical generator. Staff members would trip on the cord, and it was another sterilization cost for each surgical case.
Recently, wireless infrared (IR) and radiofrequency versions of a foot pedal have been introduced to improve upon the hazards and to facilitate easier cleaning.
“Nurses especially love the wireless pedal,” Logsdon says. “It’s easy to clean. It’s waterproof. It essentially can be dunked in a pail of water to clean. And, there is no tripping hazard that always occurs inside of an OR.”
Words Of Wisdom
Still, using any type of energy in the OR poses its own inherent risks.
“I don’t want to downplay the risk,” Dr. Ellis says. “These devices are tools and can be misused or used inappropriately and somebody can be hurt from that. Surgery is inherently a risky business and our goal in surgery is to minimize the risk as much as humanly possible.”
According to Dr. Lewis, surgical fires are still a concern today when using these instruments.
“There is a potential for fire whenever you’re in an oxygen-rich environment or in the presence of dry gauze or chemicals such as alcohol if that’s been used to prepare the patient,” he says. “You might have an environment where a spark from a monopolar electrical generator could cause a fire and that is still a concern today. The anesthesiologist and the surgeon have to be cognizant if there is oxygen in the area or other things that might catch fire.”
For Dr. Ellis, he advises surgeons to educate themselves on this technology.
“Get adequately trained,” he says. “Take [the device] to the skills lab and learn to use it. These tools can be misused. You can learn its limitations, and learn tips and tricks to using it properly.”
The different types of energies have their individual benefits for certain applications. Therefore, Dr. Ellis says, have an understanding of what the energy is being used for, and match up the adequate energy with the procedure.
You can match up the right device to the right operation,” he says, “and that’s when you’ll get the best outcomes”.