How to avoid injury to bowel during laparoscopy

How trocar injury happens

Several studies have demonstrated that abdominal adhesions place any patient into a high-risk category for trocar injury to the intestines. Patients who have undergone multiple laparotomies, like the patient in the case that opened this article, are more likely to have severe adhesions and fall into the highest risk category for bowel perforation.¹¹ It is impossible to predict with any degree of accuracy whether the intestine is adherent to the entry site.

Pneumoperitoneum can be protective

Creation of a pneumoperitoneum creates a cushion of gas between the intestines and the anterior abdominal wall (provided the intestines are not adherent to the abdominal wall). Manufacturers of disposable trocars with a retractable shield recommend creating an adequate pneumoperitoneum so that the “safety shield” deploys quickly and properly, unlike direct insertion, in which no gas is infused and space is insufficient for complete shield activation.

Open laparoscopy techniques, which allow the surgeon to enter the peritoneal cavity by direct vision without a sharp trocar, may diminish but not eliminate the risk of bowel injury.

What the data show

Of the 130 intestinal injuries recently reported by Baggish, 62 of 81 (77%) small bowel injuries were related to trocar insertion, as were 20 of 49 (41%) large intestinal injuries.¹² In other words, 82 of 130 intestinal injuries (63%) were the direct result of trocar entry.

Bhoyrul and associates reported 629 trocar injuries, of which 182 were visceral.¹³ Of the 32 deaths, six were secondary to unrecognized bowel injury. Of 176 nonfatal visceral injuries, 128 (73%) involved the intestines, and 22 were unrecognized.

Optical-access and open laparoscopic systems were designed to prevent such injuries. Sharp and colleagues reported 24 intestinal injuries out of a total of 79 complications (30%) associated with optical-access trocars after reviewing data obtained from the Medical Device Reports (MDR) and Maude databases maintained by the Food and Drug Administration.¹⁴ In the Baggish series, 4.6% of injuries were associated with open laparoscopy.¹²

Champault and colleagues reviewed complications in a survey of 103,852 operations.¹⁵ Although they recommended use of open laparoscopy as opposed to blind insertion, they presented no data on the safety of open techniques.

How intraoperative injury happens

Operative injury of the large or small bowel often occurs during sharp or blunt dissection, performed during laparoscopy using accessory mechanical or energy devices. The latter type of device is utilized increasingly because laparoscopic knot tying and suturing are rather awkward and slow, and laparoscopic suturing to control bleeding is difficult. The size of the needle required for laparoscopic suture placement must be small enough to navigate a trocar sleeve.

Avoid blunt dissection when adhesions are present

The separation of dense adhesions between the intestines and neighboring bowel, other viscera, or abdominal wall is risky when blunt dissection is used. The tensile strength of the fibrotic connective tissue may well exceed that of the thin intestinal wall. Tearing the adhesion free may bring with it a portion of the bowel wall. Such injuries are frequently missed or described as serosal injuries and left unexplored and unrepaired.

Hydrodissection is a safer alternative. It involves the infiltration of sterile water or saline under low pressure between the parietal peritoneum and underlying retroperitoneal structures, providing a safe and natural plane for dissection. In addition, when the CO₂ laser is used, the liquid acts as a heat sink to absorb any penetrating laser energy.

Energy devices create thermal effects

Energy devices used to cut tissue during operative laparoscopy coagulate blood vessels in a variety of ways, but the common pathway is thermal. Many hypotheses have evolved to explain how vessels are sealed, but none has demonstrated nonthermal activity except for cryocoagulation.

The devices most commonly used for cutting and hemostasis at laparoscopy are:

• electrosurgical (both monopolar and bipolar). Bipolar electrosurgical devices have advantages over monopolar devices when it comes to high-frequency leaks, direct coupling, and capacitive coupling.
• laser (CO₂, holmium:YAG, Nd:YAG, KTP-532, argon). As I mentioned, CO₂ laser devices are effectively backstopped by water, especially in strategic areas such as over and around intestines, major vessels, and the ureters.
• ultrasonic (Harmonic Scalpel, ultrasonic aspirator [CUSA]).

Laser and ultrasonic devices do not require a flow of electrons to create coagulation, but do produce heat that will spread peripherally by thermal conduction from the zone of impact (target).

The extent of energy-inflicted injury cannot be predicted

Inadvertent injury with energy devices can occur directly through contact with the bowel, indirectly by heat conduction through tissue, through capacitive coupling (monopolar electrical only), and by forward scatter (laser only).