Esophageal Biomechanics Revisited: A Tale of Tenacity, Anastomoses, and Suture Bite Lengths in Swine

Abstract

Anastomotic tension has repeatedly been associated with anastomotic leakages after esophagectomy for cancer or esophageal atresia repair. We therefore aimed to determine which anastomotic technique would come as close as possible to the native esophagus in sustaining traction forces. Constant traction for several minutes at esophageal remnants and large suture bites are also considered relevant in long-gap esophageal atresia repair. Porcine esophagi were subjected to linear traction using a motorized horizontal test stand. We compared breaking strengths of native esophagi to simple continuous, simple interrupted, stapled, and barbed suture anastomoses. We also investigated the effects of suture bite length and phases of constant traction on breaking strengths and powered all experiments to at least 80% using exploratory investigations (n= 5 per group). Continuous suture anastomoses had a breaking strength comparable to native esophagi (Δ=-5.25 Newton, 95% confidence interval:-10.69 to 0.19 Newton, p= 0.058) and outperformed all other investigated anastomoses (Δ ≥14.01 Newton, p ≤ 0.02). Breaking strength correlated with suture bite length (R= 0.905) and predicted breaking strength for the simple stitch (adjusted R2= 0.812, p < 0.0001), but not for anastomoses. Phases of incrementally increasing constant traction resulted in higher breaking strengths (Δ= 13.36 Newton, 95% confidence interval: 9.93 to 16.79 Newton, p< 0.0001) and higher length gain (Δ= 1.06 cm, 95% confidence interval: 0.65 to 1.48 cm, p < 0.0001) compared with controls. Only simple continuous anastomoses achieved the linear breaking strength of native tissue. Our study provides important insights in tolerance to traction forces, but its results have to be corroborated in living animals as anastomotic leakages are multifactorial processes.