Shielded vs. unshielded: Selecting the right trocar for your program is critical
Cost and safety are key issues
While technological advances have enabled more surgical procedures to be performed on an outpatient basis, there are risks associated with the use of trocars in laparoscopic surgery. Vascular injuries occur at a rate of one per 2,000 patients and make it necessary to open up the patient in 85% of the cases.1 The mortality rate for these vascular injuries is 17%. Of these injuries, 83% occur during the first trocar insertion, which is an insertion the surgeon must perform without benefit of seeing where the instrument is going.
How can same-day surgery managers and surgeons reduce the risk of vascular or other types of injuries for procedures requiring trocars? Is there one trocar that is truly "safer" than other trocars?
Some sharp-tipped trocars have a shield that slides back and forth over the tip, covering it before and after insertion. The purpose of the shield is to prevent inadvertent injury to organs or vessels during insertion.
ECRI recommends that surgery programs have shielded and unshielded trocars available for the surgeon, says Kenneth B. Ross, senior project officer, health devices group. ECRI is a Plymouth Meeting, PA-based nonprofit organization that provides information and technical assistance to the health care community.
In the November 1998 ECRI publication Health Devices, authors of the article, "Trocars: Safety and Selection" recommend that for the primary insertion, surgeons focus on selecting a trocar that will offer the greatest safety advantage, based on the surgeon’s training and experience.
"For some surgeons, this will mean using a shielded trocar," the authors say. "But for others who are well-trained in the safe use of unshielded trocars, a model without a shield may be appropriate." (For information on ordering this article, see resource box, p. 55.)
Promoting the use of shielded trocars troubles some surgeons. "The main problem with shielded trocars is the false sense of security they give a surgeon," says C. Randle Voyles, MD, a general surgeon at Mississippi Surgery Center in Jackson. "The only major trocar injury I’ve witnessed was with a shielded trocar," he adds.
When laparoscopic procedures moved from the gynecological specialty into the general surgeons’ arena with laparoscopic cholecystectomies in the late 1980s, there were a significant number of physicians who needed training in laparoscopic procedures and trocars, explains Michael S. Kavic, MD, associate professor at Northeastern Ohio University College of Medicine in Cleveland.
"Much of that training was offered by manufacturers of disposable, shielded trocars," he says. "The shield was described as a safety shield, so surgeons felt more comfortable learning with it."
Removing the term safety’
In the early 1990s, when data from numerous studies showed no real safety value from the shield, the Food and Drug Administration (FDA) required that the term "safety" be discontinued because there are no conclusive studies that support the safety claim. Only one product used for laparoscopic insertion sites, a radially expanding sleeve system manufactured by InnerDyne of Sunnyvale, CA, has received approval by the FDA to promote enhanced safety features. (See trocar alternatives, p. 56.)
Even though the term "safety" is no longer used to describe the shield, many surgeons who originally learned with a shielded trocar still prefer to use it. Some same-day surgery program managers also prefer the shielded trocar as one way to minimize, if not eliminate, risk for the primary sites of trocar insertions.
These proponents say they believe the shield will prevent the tip from hitting a vessel if the trocar is moved sidewise after insertion in the abdomen, or if an organ is close to the abdominal wall, says Vangie Paschall-Dennis, RN, CNOR, laser endoscopy coordinator for Promina Gwinnett Health System in Lawrenceville, GA.
Reducing risk an issue
Paschall-Dennis’ organization stocks shielded and unshielded trocars for surgeons to use in the hospital-based day surgery center and the freestanding center. However, she encourages the use of shielded trocars because the shield provides more protection than no shield, she explains, although a shield doesn’t guarantee a risk-free procedure. "If a shielded trocar is used, not only is it sharp, but the shield covers the tip once it goes through the abdominal wall no matter how hard the surgeon has to push," she says.
"The unshielded trocars are reusable, and they are difficult to sharpen," she explains. If the trocars are not sharpened properly, they require the surgeon to push harder to insert the trocar. The harder the surgeon has to push, the less control he or she has once the trocar breaks through into the abdominal cavity, and the risk of cutting a vessel in the cavity increases, she adds.
"I’m surprised when a surgeon chooses unshielded trocars, because even with the best surgical technique, there are always variables that can increase a patient’s risk for inadvertent injury," she says.
For example, patients with thin abdomens or patients who have undetected adhesions that connect an organ such as the bowel to the abdominal wall are at increased risk for injury, says Voyles.
When Paschall-Dennis talks with surgeons about their reasons for choosing unshielded trocars, the reason most often given is cost. Cost is not a valid reason for selecting a product if it puts patients at higher risk, she says.
The shielded trocars often are disposable and may have a higher initial cost than reusable unshielded trocars, she acknowledges. However, prices her health system has established with purchasing contracts, as well as the added costs involved in sterilizing and sharpening reusable trocars, make the cost difference between the two minimal, she explains.
Cost is an important issue for Voyles and Mississippi Surgery Center. Voyles and the other surgeons typically use an open procedure called the Hasson Technique along with a dull trocar to make the first insertion.
"In 1998, we tallied all of the disposable costs of a laparoscopic cholecystectomy performed with the open procedure and a blunt trocar. Costs for disposable instruments, gowns, gloves, steri-strips, and clips totaled $98 per case," Voyles says. "The cost of one [shielded] disposable trocar alone can be $60 or more."
Keep trocar tips sharp
The debate between shielded or disposable and unshielded or reusable often centers on the need to keep the trocar sharp enough to cut without requiring a great deal of pressure. Richard M. Soderstrom, MD, of Reproductive Health Specialists in Seattle helped develop one of the first shielded trocars, but he prefers to use a reusable unshielded trocar.
While a disposable, shielded trocar is always sharp, there is no reason for a facility to avoid a reusable one, says Soderstrom. "Most reusable trocars need sharpening after 10 uses."
The sharpness and hardness of the original tip, as well as the technique of the surgeon, determine how long a trocar stays sharp. Inspect trocars before and after each use, Soderstrom recommends. Trocar tips can become damaged or dulled if the surgeon inadvertently touches other equipment in the abdomen.
If day surgery managers opt for reusable unshielded trocars, plan for sterilization and sharpening with central supply, he says. In most cases, sharpening the tips means sending the trocar back to the supplier, and sharpening can cost about $36 per trocar.
Soderstrom has used the same trocar on more than 2,000 cases and sharpens it himself with a grinding machine he altered to fit his needs. "My trocar was manufactured by Olympus [Melville, NY] and is the sharpest I’ve seen on the market. I seldom use disposable trocars, either shielded or unshielded, but I always point out that cost should not be an issue if you are concerned about the sharpness of the trocar," he says. "If a reusable trocar costs $100 [without cannula], and you can use it at least 10 times before sharpening, then use it 10 times and throw it out. You will still spend less than the cost of a disposable trocar."
Reference
1. Champault G, Cazacu F, Taffinder N. Serious trocar accidents in laparoscopic surgery: a French survey of 103,852 operations. Surg Laparosc Endosc 1996; 6:367-70.
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