A new study from surgeons at UCLA found that laparoscopic cholecystectomies done at night for acute cholecystitis have a significantly higher rate of conversion to open than those done during daylight hours.

Nighttime cholecystectomies were converted 11 percent of the time vs. only 6 percent for daytime operations, p = 0.008, but there was no difference in the rates of complications or hospital lengths of stay.

The study, published online in the American Journal of Surgery, was a retrospective review of 1140 acute cholecystitis patients, 223 of whom underwent surgery at night.

The authors advocate delaying surgery until it can be done in the daytime, but this conclusion needs to be examined.

Although the percentage of gangrenous gallbladders was similar in both groups, it wasn’t clear from the data how many patients were semi-elective and how many were true emergencies.

Operative procedure durations were 110.5 minutes for nighttime and 92.4 minutes for daytime cases, and 1.5 and 2.0 days elapsed respectively before the patients were taken to the operating room, both p < 0.0001. The hospital lengths of stay were similar at 3.7 days for the night group and 3.8 days for the day patients. The causes for these lengthy operations, delays in operating, and long hospital stays were not explained in the manuscript.

The authors acknowledged that patient follow-up was no better than 50%.

Unreported confounders such as variations in the level of skill of the surgeons or whether or not a resident did the procedure could have influenced the results.

Another recently published study from the University of Texas Health Science Center in Houston found that although there was a slight but significant increase in complication rates (mostly retained stones and superficial wound infections) for patients having cholecystectomies at night, conversion rates of day and night surgery were similar.

Durations of operations averaged about 80 minutes (a more realistic figure than those in the UCLA study) in both groups. Hospital lengths of stay were significantly shorter (2 days vs. 3 days) for the nighttime patients. The authors acknowledged that a limitation of their study was that severity of gallbladder disease was difficult to accurately assess.

The decision about timing of cholecystectomy for acute cholecystitis depends on the availability of operating rooms, the severity of illness, the presence of comorbidities such as diabetes, and the surgeon’s schedule and other responsibilities.

Most surgeons agree that the sooner patients with acute cholecystitis undergo surgery, the more quickly they will recover and get back to normal activities.

In my own practice as a solo community hospital surgicalist taking care of emergency cases only, any patient with acute cholecystitis who I was consulted on before 6 or 7 pm had surgery that same night if an OR was available. If not, they always had the operation within 24 hours. The length of stay (LOS) averaged under 48 hours and the median LOS was 1 day.

Because one of the two hospitals involved in the UCLA study is a major trauma center in Los Angeles, the paper’s findings may not apply to other institutions where nighttime OR availability may be better.

Based on these papers, surgeons and patients should not be wary of undertaking cholecystectomies during evening hours.

“Skeptical Scalpel” is a surgeon blogs at his self-titled site, Skeptical Scalpel.