Effect of mechanical reinforcement on stability of the rotary door flap laryngotracheal reconstruction: A canine study

Objective/Hypothesis: The rotary door flap (RDF) laryngotracheal reconstructive procedure uses a 180°rotation of the sternohyoid muscle into a laryngofissure. Despite excellent clinical results, there are concerns of flap inspiratory prolapse. This study examined RDF stability and the efficacy of ancillary materials in providing additional support. Methods: Seventeen dogs underwent endoscopic induction of subglottic stenosis and delayed RDF reconstruction. Animals received 1) traditional RDF (control), 2) RDF with titanium screen implant, 3) RDF with porous polyethylene implant, or 4) RDF with hydroxyapatite cement (HAC) injection. Four weeks postoperatively the flaps were tested for stability. On qualitative assessment, endoscopic visualization was completed with quiet respiration and then following endotracheal tube occlusion. On quantitative assessment, after animals were killed, the RDF segment was isolated and subjected to negative pressure (maximum pressure, -50 mm Hg). The pressure-causing collapse was measured. Results: In the traditional RDF animals (control), five of six flaps were stable in vivo and with negative pressures. In the titanium screen, porous polyethylene group, and HAC groups, respectively, four of four, three of four, and two of three flaps were stable in vivo and under negative pressure. Flaps that demonstrated instability had granulation, dehiscence, and poor healing. These occurred in 1 of 6 animals in the traditional RDF group and in 2 of 11 animals in the implant groups. In addition, 13 of 24 animals assigned to the implant groups died, compared with 2 of 8 of those in the traditional RDF group. Conclusions: The RDF is stable and maintains the airway under physiological conditions. Support materials did not improve stability, render flap harvest more difficult, or increase morbidity and mortality.