gms | German Medical Science

Background: Bariatric surgery is the recommended treatment option for patients suffering from morbid obesity. Out of the existing bariatric procedures, Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the most commonly performed. During LRYGB surgery a Roux-en-Y anastomosis is constructed that consists of two bowel limbs. The length of these bowel limbs has an effect on the success of the treatment. However, an online survey among American bariatric surgeons revealed that only 53% of bariatric surgeons measure the lengths of bowel limbs. 87% of surgeons who measured their limbs used laparoscopic distance markers and 13% used a suture or premeasured umbilical tape. Both methods appear to be either hard to utilize or are poorly integrated into the surgical workflow. Therefore a phantom trial was performed to evaluate accuracy, traumatic impact and usability of these bowel measurement methods compared to a novel computer-assisted bowel measurement system developed in our group (BMS).

Materials and methods: For the evaluation four bowel length measurement methods were compared in a phantom trial: guessing, distance marks on laparoscopic graspers, premeasured umbilical tape and BMS. Trials were performed with a 3D-laparoscope (3D TipCam 1 Spies™, Karl Storz GmbH, Tuttlingen, Germany) on bowel phantoms within a standard box trainer. All participants (n=24) were classified according to their laparoscopic experience. A total of 7 measurements until 70 cm were conducted. For assessment of the learning curve, length estimation was performed by guessing 4 times alternating with the other measurement methods that were in a randomized order. For each measurement method an instruction video was shown and time was given to practice the method. Start and end point of each measurement were marked with pins and total distance was measured manually. Time and number of bowel grasps were also recorded.

Results: Preliminary results showed that participants measured bowel most accurately with umbilical tape (68.9 +/- 2.95 cm) and BMS (68.65 +/- 1.85 cm). Measurement with laparoscopic distance marks (64.6 +/- 8.72 cm) resulted in an accuracy comparable to guessing (66.18 +/- 10.03 cm). Bowel had to be grasped most often when applying laparoscopic distance markers (14.7+/- 3.83) and least with guessing (14.7 +/- 3.83) and BMS (14.71. +/- 2.94). The most time needed by participants to measure bowel was with BMS (192.13 +/- 65.06 s) and umbilical tape (171.46 +/- 56.24 s).

Conclusion: Bowel length measurement methods commonly used by most bariatric surgeons are not accurate and account for more bowel grasps, suggesting a higher potential for bowel trauma than other methods. Umbilical tape and BMS seem to be most suitable for laparoscopic bowel length measurement, yet BMS allows for individual length measurements and does not need preparation. Further experiments with more participants are necessary to validate the preliminary results.

Acknoweldgements: This research was funded by the German Research Foundation (DFG) within the Transregional Collaborative Research Center 125 „Cognition Guided Surgery“ in project A01 and by the Medical School of Heidelberg University with a physician scientist fellowship for Martin Wagner.