Modern surgical treatment of otosclerosis - Helda - Helsinki.fi

Discussion
The patient also would achieve the advantage of binaural hearing without a waiting time
between operations.
Study (I) with simultaneous bilateral surgery for otosclerosis was initiated after the careful
exploration of the long-term results of a large patient population in conventional stapes
surgery. In the past, some authors have discouraged bilateral surgery because of the risk of
SNHL, which can occur years after surgery (Ludman and Grant 1973, Smyth et al. 1975,
Hammond 1976). In a study by Ludman and Grant (1973) there was a high rate of dead
ears (3.4%) during the first postoperative year, with another 2.9% occurring later, half of
these more than six years postoperatively. However, with modern surgical methods and
equipment, the risk of inner ear trauma seems to have diminished compared with older
studies. In a large series of 1800 bilateral partial stapedectomies presented by Daniels et
al. (2001), there were no dead ears, and in another study of 3050 stapedotomies by
Vincent et al. (2006) there were only two cases (0.07%) of dead ears. Reports on longterm
success and safety have also shown stability of these results (House et al. 2002,
Aarnisalo et al. 2003, Vincent et al. 2006). The proportion of surgeons willing to operate
on both sides has increased in recent years. However, no consensus exists regarding the
optimal period between the two surgeries (Raut et al. 2002).
With the encouraging results of stapes surgery today, this study was undertaken to
evaluate the outcome of simultaneous bilateral stapes surgery. All patients were fully
informed about the risks and experimental nature of the operative approach. The risk of
unilateral severe SNHL or vestibular function, based on prevailing literature and our
institutions’ 20-year follow-up results of stapes surgery, was estimated to be less than 1%.
This means a bilateral risk of less than 0.01% if the ears are considered to be independent
of each other. The patients were informed about the actual risk of 0.01-1% for a bilateral
complication. Special attention was paid to ensuring that the risk of complications
remained as low as possible. Patients included in the study were otherwise healthy and had
not undergone any previous otosurgeries. An experienced surgeon operated on both ears
with general anaesthesia, all dressings and instruments were changed between sides and
intravenous antibiotic prophylaxis was administered during the operation. To avoid
problems due to the prostheses itself, prosthesis from different quality lots or
manufacturers were selected for the right and left ears of the patient. If any technical
problems occurred in the first ear, any procedures on the second ear were delayed to a
future session. The study was executed in two parts; data from the first half of the study
group were analysed before we proceeded with the remaining patients.
Hearing results with mean postoperative AB-GAP of 7 dB are comparable with the 8 dB
result in our institution’s previous study on unilateral stapes surgery and in the literature in
general (Aarnisalo et al. 2003). The success rate of AB-GAP within 10 dB in at least one
ear was 100%, and in 81% of the patients this was achieved this bilaterally. Afterwards,
successful revision surgery was performed on the only patient with an unsatisfactory
postoperative AB-GAP of over 15 dB. This success rate resembles those of larger studies
(Daniels et al. 2001, Vincent et al. 2006).
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