The exchange of letters in the June issue was provocative (“Optical-access trocars: Good idea or higher risk?”). In my experience, direct trocar insertion is safer and saves time. Transumbilical insertion is best because the umbilicus is the thinnest part of the abdominal wall and the peritoneum is firmly attached to it, but trans-culde-sac insertion using a Veress needle is the better option if abdominal insertion is not possible in extremely obese patients.
In addition, in prolonged procedures, nitrous oxide makes a safer insufflation medium because it lacks the biochemical side effects of carbon dioxide. In fact, direct trocar insertion with nitrous oxide insuffla-tion and a single-puncture laparoscope is an ideal setup in average, low-risk patients undergoing minor procedures under local and/or intravenous mild sedation and no uterine manipulation.
Hamid H. Sheikh, MD
Dr. Michael Baggish Responds:
Direct trocar insertion is an acceptable alternative to establishing pneumoperitoneum prior to trocar insertion. However, direct trocar insertion (no pneumoperitoneum) should be attempted with great caution when using a disposable device. Manufacturers recommend creating pneumoperitoneum to produce the most favorable environment for the shield to deploy. If an adverse outcome occurs because of a disposable trocar injury, the surgeon could be accused of failing to heed the manufacturer’s written instructions for proper use of the trocar.
I find it hard to believe that a Veress needle (with a tip-to-hub measurement of 5 inches) cannot penetrate the most obese abdominal wall at the umbilicus. I prefer to create a pneumoperitoneum with a 3.5-inch Touhy epidural needle and have never failed to achieve pneumoperitoneum, even in a very obese person. In fact, I believe the unnecessarily long Veress needle presents some inherent penetration risks to underlying structures.
As for nitrous oxide, it does have advantages over carbon dioxide gas in that it is less irritating to the peritoneum. However, it also supports combustion (an electrosurgical device risk). Both gases tend to unfavorably cool the patient, especially when they are utilized over a protracted time.