Surgeons who are good at one type of weight-loss surgery aren't necessarily good at other operations for the same purpose, a new study shows.

The findings "suggest that a surgeon's skill with one operation may not translate into other seemingly similar operations," investigators say.

In the first phase of the research, 20 bariatric surgeons from across the U.S. had videos taken while they performed gastric bypass operations to help people lose weight.

Thirty-three other surgeons reviewed the videos and rated them according to surgical skill, without knowing the identities of the doctors they were watching.

When the video-based ratings were compared to results in more than 10,000 of the surgeons' actual patients, "surgeons who were rated highly by their peers had less complications," Dr. Oliver Varban told Reuters Health via email.

Therefore, Varban said, his team "asked the next logical question: 'Can the skill ratings for one procedure (gastric bypass) help us predict the outcomes for another, similar procedure (sleeve gastrectomy)?'"

"Our data revealed that it didn't," he added.

The surgeons in the gastric bypass videos had been divided by their peers into top, middle, or bottom categories for skill.

When Varban and colleagues looked back at nearly 7,700 sleeve gastrectomy surgeries performed by the same 20 surgeons, they found that all 20 had similar rates of surgical and medical complications, regardless of how skilled they were at gastric bypass operations.

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For instance, overall complication rates after sleeve gastrectomy were 5.7 percent for top-rated surgeons, 6.4 percent for the middle surgeons, and 5.5 percent for the bottom, according to a report in the journal Surgery.

Hospital readmission rates were 3.8 percent for top-rated surgeons, 4.8 percent for the middle surgeons, and 3.1 percent for the bottom. The reoperation rate was 1.1 percent for all skill levels.

One reason why skill in one surgery didn't predict skill in another surgery may be that the operations aren't similar enough, Dr. James Ames, Orthopedic Sports Medicine Surgeon at Dartmouth-Hitchcock Medical Center told Reuters Health via phone. Dr. Ames, who wasn't involved in this research, has studied whether surgeons' skill could be transferred between total hip and partial hip replacement.

Varban and his colleagues agreed. While both surgeries in this study are related, some of the skills required aren't similar, they say.

In a gastric bypass, the top of the stomach is sealed off, leaving a small pouch that is then connected directly to the middle part of the small intestine. In a sleeve gastrectomy, the structure of the stomach is changed to be shaped like a tube.

Both operations restrict the amount of calories the body absorbs - but one requires more sewing skill while the other requires more dissection skill. "So, if we are to use video-based skill ratings to evaluate surgical quality, each procedure needs to be evaluated separately," said Varban.

On the bright side, according to Varban, collecting videos of surgeries helps improve overall surgical quality.

"By combining video-based data with clinical outcomes, we can determine best practices with regards to technique and set standards with regard to skill," he said.