Ossicular Reconstruction with TORP: Does Malleus has a Role?

Abstract

Malleus has a catenary lever mechanism in sound transmission in a normal ear leading to better acoustic signal at the footplate. However, the literature is rife with controversy regarding its role in ears where hearing has been restored using a prosthesis. Though the presence of malleus has prevented lateralization of graft in reconstructed middle ear, consensus on role of malleus on outcomes of ossiculoplasty malleus is still unclear. It's a prospective longitudinal study with 60 patients randomised into two groups. Both the groups had reconstruction done with TORP. In one group malleus was preserved (M +)and placed over the TORP using malleus relocation technique while in another group malleus was intentionally removed(M -). Both the groups were compared for Improvement in hearing, AB gap and stability of the implant. Age group more than 40 years was most affected in both groups followed by age group between 15 and 30 years. There was equal incidence of males and females in (M -) group and Incidence of Females was 60 percent versus 40 percent males in (M +) group. Preoperative PTA of moderate conductive hearing loss (40-55db) was most found followed by severe conductive hearing loss (> 55db) with standard deviation of 7.155 and mean hearing loss was 46.30db in (M +) group. Post operative pure tone averages improved to mild hearing loss (26-30db) in about 90percent of patients with mean of 32db and standard deviation of 7.06 in (M +) group Preoperative PTA of severe conductive hearing loss (> 55 db.) was most found followed by moderate conductive hearing loss (45-55db)with standard deviation of 6.471 and mean hearing loss was 47 db in (M-)group.Post operative pure tone averages improved to mild hearing loss (26-30 db.) in about 90 percent of patients with mean of 33 db and standard deviation of 5.431 in (M -) group. The average reduction in AB gap in (M +) was 22.61db with std deviation of 0.08 while in (M-) it was 17.61 with std deviation of 2.0.). The difference for improvement in hearing between both the groups was not statistically significant. The intergroup reduction in AB gap was also statistically insignificant. The extrusion was seen in 1 case in (M +) and 6 cases in (M-). This difference between both the groups was statistically significant. If malleus is used by an otologist to stabilize the implant its role becomes significant in long term outcomes of ossiculoplasty, however it doesn't contribute as far as hearing improvement or reduction AB gap is concerned.