Repair of Oronasal Fistulae by Interposition of Multilayered Amniotic Membrane Allograft

Background: Oronasal fistulas are a frequent complication after
cleft palate surgery. Numerous repair methods have been described,
but wound-healing problems occur often. The authors investigated,
for the first time, the suitability of multilayered amniotic
membrane allograft for fistula repair in a laboratory experiment
(part A), a swine model (part B), and an initial patient series
(part C). Methods: In part A, one-, two-, and four-layer porcine
and human amniotic membranes (n = 20 each) were fixed in a digital
towing device and the force needed for rupture was determined. In
part B, iatrogenic oronasal fistulas in 18 piglets were repaired
with amniotic membrane allograft, autofetal amniotic membrane, or
small intestinal submucosa (n = 6 each). Healing was evaluated by
probing and visual inflammation control (no/moderate/strong) on
postoperative days 3, 7, 10, and 76. Histological analysis was
performed to visualize tissue architecture. In part C, four
patients (two women and two men, ages 21 to 51 years) were treated
with multilayered amniotic membrane allograft. Results: In part A,
forces needed for amniotic membrane rupture increased with
additional layers (p < 0.001). Human amniotic membrane was
stronger than porcine membrane (p < 0.001). In part B, fistula
closure succeeded in all animals treated with amniotic membrane
with less inflammation than in the small intestinal submucosa
group. One fistula remained persistent in the small intestinal
submucosa group. In part C, all fistulas healed completely without
inflammation. Conclusions: Amniotic membrane is an easily available
biomaterial and can be used successfully for oronasal fistula
repair. The multilayer technique and protective plates should be
utilized to prevent membrane ruptures.