Effects of experience and reference tools on laparoscopic length measurements

Measuring Small Bowel Length in Bariatric Surgery: An Ex Vivo Laparoscopic Training Experiment

INTRODUCTION

Determining limb length in gastric bypass procedures is a crucial step to ensure significant weight loss without risking malnutrition. This study investigated the effect of ex vivo training on the skills needed to determine limb lengths.

MATERIALS AND METHODS

This was a single-center ex vivo training experiment in a teaching hospital in the Netherlands. We designed a training exercise with marked ropes in a laparoscopic trainer box. All ten surgical residents participated and practiced the skill of estimating limb length. Before and after the two-week period their results on a 150-centimeter limb length task were evaluated.

RESULTS

Before training, 10 surgical residents estimated 150 centimeters of small bowel with an absolute deviation of 21% [range 9-30]. After the training experiment, the residents measured with 8% [2-20] deviation (P = .17). The 8 residents who trained sufficiently improved statistically significantly to an absolute deviation of 5% [2-17] (P = .012). Over 70% of the participants felt their skills had improved.

CONCLUSIONS

With sufficient training, surgical residents' skills in measuring small bowel length improved when tested in an ex vivo model. Residents became more confident in their laparoscopic measurement skills. This ex vivo training model is a alternative and addition to on-site training.

Laparoscopic Small Bowel Length Measurement in Bariatric Surgery Using a Hand-Over-Hand Technique with Marked Graspers: an Ex Vivo Experiment

Introduction

Tailoring limb length in bariatric surgery is a subject of many studies. To acquire the optimal limb length, accurate measurement of the small bowel length is essential.

Objective

To assess the intra- and inter-individual variability of laparoscopic bowel length measurement using a hand-over-hand technique with marked graspers.

Method

Four bariatric surgeons and four surgical residents performed measurements on cadaver porcine intestine in a laparoscopic box using marked graspers. Each participant performed 10 times a measurement of three different lengths: 150, 180, and 210 cm. Acceptable percentage deviation from the goal lengths was defined as less than 10%, while unacceptable deviations were defined as more than 15%.

Results

The bariatric surgeons measured the 150-, 180-, and 210-cm tasks with 4% (CI 0.4, 9), − 6% (CI − 11, − 0.8), and 1% (CI − 4, 6) deviation, respectively. In total, the bariatric surgeons estimated 58 out of 119 times (49%) between the margins of 10% deviation and 36 times (30%) outside the 15% margin. Considerable inter-individual differences were found between the surgeons. The surgical residents underestimated the tasks with 12% (CI − 18, − 6), 16% (CI − 19, − 13), and 18% (CI − 22, − 13), respectively.

Conclusion

Bariatric surgeons estimated bowel length with on average less than 10% deviation. However, this still resulted in 30% of the measurements with more than 15% deviation. There were considerable inter-individual differences between the surgeons and residents structurally underestimated the bowel length. Ascertainment of measurement accuracy and adequate training is essential for bariatric procedures in which limb length is of importance.

Graphical abstract

Comparison of Conventional Methods for Bowel Length Measurement in Laparoscopic Surgery to a Novel Computer-Assisted 3D Measurement System

Purpose

Accurate laparoscopic bowel length measurement (LBLM), which is used primarily in metabolic surgery, remains a challenge. This study aims to three conventional methods for LBLM, namely using visual judgment (VJ), instrument markings (IM), or premeasured tape (PT) to a novel computer-assisted 3D measurement system (BMS).

Materials and Methods

LBLM methods were compared using a 3D laparoscope on bowel phantoms regarding accuracy (relative error in percent, %), time in seconds (s), and number of bowel grasps. Seventy centimeters were measured seven times. As a control, the first, third, fifth, and seventh measurements were performed with VJ. The interventions IM, PT, and BMS were performed following a randomized order as the second, fourth, and sixth measurements.

Results

In total, 63 people participated. BMS showed better accuracy (2.1±3.7%) compared to VJ (8.7±13.7%, p=0.001), PT (4.3±6.8%, p=0.002), and IM (11±15.3%, p<0.001). Participants performed LBLM in a similar amount of time with BMS (175.7±59.7s) and PT (166.5±63.6s, p=0.35), but VJ (64.0±24.0s, p<0.001) and IM (144.9±55.4s, p=0.002) were faster. Number of bowel grasps as a measure for the risk of bowel lesions was similar for BMS (15.8±3.0) and PT (15.9±4.6, p=0.861), whereas VJ required less (14.1±3.4, p=0.004) and IM required more than BMS (22.2±6.9, p<0.001).

Conclusions

PT had higher accuracy than VJ and IM, and lower number of bowel grasps than IM. BMS shows great potential for more reliable LBLM. Until BMS is available in clinical routine, PT should be preferred for LBLM.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11695-021-05620-6.