Modern surgical treatment of otosclerosis - Helda - Helsinki.fi

Abstract
Abstract
The era of modern surgical treatment of otosclerosis started in 1956, when Shea
successfully removed stapes and reconstructed the ossicular chain with a Teflon prosthesis
after sealing the oval window with a thin skin graft. Total stapedectomy is still used
successfully, but more commonly today only a small opening is made in the stapes
footplate with a micro-drill or laser. Through the small stapedotomy opening a piston
prosthesis attached to the long process of the incus can be introduced into the vestibulum
and only the stapes superstructure is removed. Both techniques are effective in long-term
restoration of hearing. Surgical treatment still contains the risk of inner ear damage, but
with in last few decades the risk of sensorineural hearing loss (SNHL) has decreased
significantly. This could be due to technical evolution in equipment (laser, microscope,
instruments, prosthesis) used in surgery, but also the trend favouring stapedotomy might
have some effect. In the early stages of stapes surgery, only one ear was operated on
because of the fear of SNHL. Nowadays, more surgeons are willing to operate on both
sides since the safety of stapes surgery has increased markedly. Simultaneous bilateral
surgery has not been reported in stapes surgery, but has been introduced with success in
ophthalmology and orthopaedic surgery. Simultaneous surgery would give the patient the
opportunity to gain advantages of bilateral hearing within one session, with less time spent
in hospital and on sick leave. Although SNHL after surgery is rare, vestibular symptoms
are common. Fortunately, vestibular symptoms are usually mild and short lasting, but in
some cases they can prevent the patient to be treated as outpatient. The mechanism for
vestibular symptoms and the exact end organ affected is still unveiled. This thesis presents
the results of experimental simultaneous bilateral stapes surgery, and vestibular symptoms
and findings before and after unilateral stapes surgery. In addition, we explore reasons for
outpatient failures in otosclerosis surgery.
Study I examines the outcome of simultaneous bilateral surgery. Both ears of patients
suffering from bilateral otosclerosis were operated on in a single session. Hearing and
balance of patients were objectively measured during the one-year follow-up. Hearing was
evaluated with standard pure tone and speech audiograms and vestibular apparatus with
visual feedback posturography (VFP). Subjective estimation of hearing, vestibular
symptoms and quality of life were assessed with questionnaires. In study II, reasons for
outpatient failures in stapes surgery were explored. Forty-seven consecutive stapedotomies
and stapedectomies performed by the same surgeon as outpatient surgeries were included.
Applicability of these two operative methods for outpatient surgery was examined and the
effect of failures on hearing results were analysed. Postoperative vestibular symptoms and
the end organ(s) affected were investigated in studies III and IV. With video-oculography
(VOG), eye movements were measured preoperatively and at one week, one month and 3
months postoperatively in the first phase (III). In the second phase (IV), recordings were
obtained at a mean of four hours postoperatively.
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