Descriptive data
Presenting complaints of ears with LFs were 80% (12/14) hearing loss, 79% (11/14) otorrhea, 29% (4/14) giddiness, 7% (1/14) tinnitus, 7% (1/14) facial palsy and 7% (1/14) otalgia. 65% (9/14) ears had both hearing loss and otalgia.
HRCT accurately identified 13 of the 14 LFs diagnosed intraoperatively, with a false positive of 4 ears and false negative of 1 ear. This reflected a sensitivity of 93% (13/14) and specificity of 95% (72/76) in the identification of LFs through semicircular canal dehiscence. All fistulas were located in lateral SCC and 7% (1/14) in superior SCC.
In LF group, intraoperative dehiscence was observed – 29% (4/14) in facial canal, 64% (9/14) tegmen tympani. Ossicular erosion occurred in 79% (11/14) stapes, 79% (11/14) incus and 93% (13/14) malleus. Intraoperative squames were found, 93% (13/14) attic, 93% (13/14) middle ear and 71% (10/14) mastoid. Ossicular chain encasement occurred in 71% stapes (10/14), 93% (13/14) incus and 79% malleus (11/14). Compared to non-LF group, LF group noted a significantly higher incidence of stapes erosion (p<0.001), dehiscence in tegmen tympani (p=0.016) and SCC (p<0.001) [Table 1].