Int. Adv. Otol. 2009; 5(3); 310-317

Prognostic factors for hearing preservation in surgery of chronic otitis media
Viktor Chrobok,  Arnošt Pellant, Milan Meloun, Karel Pokorný, Eva Šimáková, Petra Mandysová  

Department of Otolaryngology and Head and Neck Surgery, Regional Hospital of Pardubice, viktor.chrobok@nemocnice-pardubice.cz

Objectives/Hypothesis: The aim of this study was to observe the impact of prognostic factors (the Middle Ear Risk Index [MERI]
by Becvarovski and Kartush) on hearing of patients surgically treated for chronic otitis media. Furthermore, the aim of the study
was to determine which of the monitored factors (otorrhea, eardrum perforation, cholesteatoma, ossicular status, middle ear granulations
or effusions, previous surgery, and smoking) were linked to greater hearing impairment.

Study Design: Retrospective case review.

Materials and Methods: The level of hearing was assessed for each preoperative prognostic factor category in a total of 155
patients surgically treated for chronic otitis media at the Department of Otolaryngology and Head and Neck Surgery in Pardubice,
Czech Republic, between 1996 and 2004. A pre-op and post-op statistical analysis of each patient’s hearing was conducted by
pure-tone audiometry using the MERI.

Results: Patients with a perforated eardrum had poorer hearing than patients with an intact eardrum at frequencies of 0.5 to 3
kHz before surgery and at all frequencies after surgery (by 7 to 13 dB, p < 0.05). Statistically, patients with cholesteatoma had a
much greater air conduction hearing loss, i.e. by 8 to 18 dB (p < 0.05), at all frequencies both pre-op and post-op compared to
patients without cholesteatoma. Patients with an intact ossicular chain had the best pre-op and post-op hearing; their hearing was
signficantly better compared to a group of patients suffering from a defective incus and compared to a group of patients with
defects apparent in (p < 0.05). In patients undergoing revision surgery, pre-op and post-op air conduction was significantly worse
compared to a group of patients with a history of a different type of ear operation prior to this study (p < 0.05). Smokers had a
lower pre-op and post-op hearing threshold; however, a significant difference was found only at high-frequency air conduction (3
and 4 kHz) post-op, when it deteriorated by 14 and 12 dB (p < 0.05).
No major hearing threshold difference was found between patients who either had or did not have middle ear granulations and
otorrhea.
Patients with a generally lower MERI had better pre-op and post-op air and bone conduction than patients with a higher MERI (p
< 0.05). In patients with a MERI of 0 to 3 (minor disorder), post-op air conduction at frequencies of 0.5 to 3 kHz improved by 4 to
6 dB. In a group with a MERI of 4 to 6 (a moderate disorder), air conduction at frequencies of 3 and 4 kHz deteriorated by 4 and
5 dB, and in patients with a MERI of 7 or higher (a severe disorder), air conduction declined at all frequencies by 1 to 7 dB.

Conclusions: An evaluation of pre-op and post-op hearing revealed that highly significant pre-op negative prognostic factors
included the presence of cholesteatoma, the presence of perforation of the tympanic membrane, ossicular status, previous
surgery, and the overall sum of the MERI. Smoking was a less significant negative factor. Minor prognostic factors included the
presence of middle ear granulations and otorrhea. Patients with a higher overall MERI had a more severe impairment of air and
bone conduction hearing threshold pre-op and post-op compared to patients with a lower MERI.