BETA-2-TRANSFERRIN CONFIRMS PERILYMPHATIC FISTULA IN CHILDREN

beta 2-Transferrin is a protein that is unique to the cerebrospinal fl uid and aqueous humor. On the basis of this information and a recent s tudy from our institution that demonstrated that beta(2)-transferrin w as also unique to human perilymph, a prospective double-blind study to evaluate perilymphatic fistula in children was performed. Attending o tolaryngologists at Children's Hospital of Pittsburgh evaluated and re commended surgery for 10 children (10 ears) who were suspected of havi ng a congenital perilymphatic fistula. During the operation, the surge on decided whether a perilymphatic fistula existed; on the basis of ot omicroscopic findings, and then separate pieces of gelatin sponge were placed on the oval and round windows, respectively, and sent to the i mmunopathology laboratory where they were analyzed for beta 2-transfer rin. Ten patients (10 ears) undergoing tympanoplasty or tympanomastoid ectomy were used as controls and tested in a similar fashion. During t he 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 beta 2-transferrin. O f the 10 patients undergoing exploratory tympanotomy for perilymphatic fistula, I ear was thought to be negative for perilymphatic fistula o n microscopic visual examination, whereas 9 were considered to be posi tive for perilymphatic fistula. No beta 2-transferrin was identified f rom the ear that was considered not to have a perilymphatic fistula, w hereas six of the nine ears that were thought to have perilymphatic fi stula tested positive for beta 2-transferrin. beta 2-Transferrin, an o bjective test for perilymphatic fistula, agreed with the microscopic v isual determinations in 66.7% of ears noted to have a perilymphatic fi stula. This study confirms the existence of congenital perilymphatic f istula in children. Further investigation is needed to determine the t rue sensitivity and specificity of this new laboratory test for perily mphatic fistula.