Background

Study the clinical impact of TBL variability on fixed limb duodenal switch (DS).

Methods

From Sept 2018 through April 2019, a single surgeon measured the TBL of 45 patients who received a DS with a total alimentary limb (TAL) of 300 cm and common channel length (CC) of 150 cm. The patients were divided into quartiles based on the ratio of TAL/TBL, representing the proportion of small bowel used for absorption. Analyses with regards to weight loss and nutritional labs were performed to compare the 1st quartile (1stQ) (longest TBL) and 4th quartile (4thQ) (shortest TBL).

Results

The average TBL was 668 cm (range: 530-900 cm). The average TAL/TBL ratio differed between 1stQ (38%, range 33%-41%) and 4thQ (54%, range 50%-57%) (p<0.0001). EWL was similar between quartiles at 1 year postop (EWL: 1stQ=87%, 4thQ=74%, p=0.13), however differed at 2, 3, and 4 years, favoring lower TAL/TBL (EWL 4 years: 1stQ=86% vs 4thQ=49%, p=0.0061). There was no difference in average albumin, Vit A, or PTH levels between quartiles at years 1-4. Average Vit D levels were lower in 4thQ at years 2 and 3 postop. In multivariate analysis, TAL/TBL was the only significant predictor of EWL.

Conclusions

A lower TAL/TBL ratio is the most significant factor influencing better weight loss outcomes after DS with a fixed TAL and CC. Nutritional outcomes compared favorably between groups. Adjusting TAL and CC lengths should be considered in the extremes of TBL, both short and long.