β2-Transferrin Confirms Perilymphatic Fistula in Children

Abstract

β2-Transferrin is a protein that is unique to the cerebrospinal fluid and aqueous humor. on the basis of this Information and a recent study from our Institution that demonstrated that β2-transferrin was also unique to human perilymph, a prospective, double-blind study to evaluate perilymphatic fistula in children was performed. Attending otolaryngologists at Children's Hospital of Pittsburgh evaluated and recommended surgery for 10 children (10 ears) who were suspected of having a congenital perilymphatic fistula. During the operation, the surgeon decided whether a perilymphatic fistula existed, on the basis of otomicroscopic findings, and then separate pieces of gelatin sponge were placed on the oval and round windows, respectively, and sent to the immunopathology laboratory where they were analyzed for β2-transferrin. Ten patients (10 ears) undergoing tympanoplasty or tympanomastoidectomy were used as controls and tested in a similar fashion. During the study, both the surgeons and patients were blinded from the results of the test. of the 10 control patients, none was observed to have a perilymphatic fistula, and all were negative for β2-transferrin. of the 10 patients undergoing exploratory tympanotomy for perilymphatic fistula, 1 ear was thought to be negative for perilymphatic fistula on microscopic visual examination, whereas 9 were considered to be positive for perilymphatic fistula. No β2-transferrin was identified from the ear that was considered not to have a perilymphatic fistula, whereas six of the nine ears that were thought to have perilymphatic fistula tested positive for β2-transferrin. β2-Transferrin, an objective test for perilymphatic fistula, agreed with the microscopic visual determinations in 66.7% of ears noted to have a perilymphatic fistula. This study confirms the existence of congenital perilymphatic fistula in children. Further investigation is needed to determine the true sensitivity and specificity of this new laboratory test for perilymphatic fistula.