Modern surgical treatment of otosclerosis - Helda - Helsinki.fi

Studies III and IV
Materials and methods
These two studies differ from each other mainly in the timing of the VOG measurements.
Study III included 33 patients scheduled for a stapedotomy due to otosclerosis, and Study
IV included 21 patients scheduled for a stapedotomy or tympanoplasty with the objective
of opening the oval window. In Study III, in four of the cases, the other ear had already
been operated on due to otosclerosis, and in one case both ears had been operated on, but
revision surgery was necessary. In Study IV, two patients had staged tympanoplasty after
primary cholesteatoma surgery, and one patient had fractured stapes crura caused by head
trauma. All other operations were due to otosclerosis. In all cases, the inner ear fluid
compartment was opened during surgery. Five patients with otosclerosis had their other
ear operated on previously, and for one patient the surgery was a revision of a previous
procedure. Both studies were prospective, and VOG was recorded during standard pre-
and postoperative visits. The patients did not have any other neurotological diseases or
medications. In Study III, eye position curves were recorded with VOG preoperatively as
well as at one week, one month and 3-4 months postoperatively. Data about subjective
vestibular symptoms were collected during every visit using a questionnaire (Appendix 1).
In Study IV, VOG was measured, on average, four hours after the surgery. VOG
measurements are described later in the VOG section and in the original papers.
Postoperative hearing was assessed, and the associations between vestibular symptoms,
hearing results and VOG findings were evaluated.
4.2 Surgery
In Study I, the general anaesthetic was used for all patients. The surgical approach was
either transcanal (26 ears) or endaural (10 ears). Special care was taken to avoid
postoperative infection. All patients had a single dose of cefuroxime 1.5 g or ceftriaxone 2
g as an antibiotic prophylaxis during surgery. The same surgeon operated on both ears,
and dressings and instruments were changed after surgery on the first ear was concluded.
The second side was then prepared for surgery. Stapedotomy was done using a laser (5
ears) or a micro-drill (31 ears). In two cases, a partial stapedectomy was performed
because of an unintended fracture of the footplate. Patients received prostheses selected
from different manufacturers or quality lots on each side in order to minimize the risk of
infection or other mechanical complications due to the prosthesis. Titanium (n=30) or steel
(n=6) piston prostheses with a diameter of 0.4-0.6 mm were used. All prostheses were
crimped manually to the long process of the incus. After inserting the prosthesis, the
opening on the footplate was sealed with small pieces of fascia or with blood. All patients
were treated as inpatients.
In Study II, a Schucknecht piston with a diameter of 0.6 mm was placed over the fascia
after the complete removal of the footplate in the total stapedectomy group. In the
stapedotomy group, the same prosthesis was inserted using an argon laser-made fenestra.
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