Chapter 14 Stapedectomy has evolved from total removal of the footplate to the small fenestra technique. Improvement of hearing, especially improvement of speech discrimination scores, has been cited as justification for employing the small fenestra technique for most stapedectomies. Studies on the small fenestra technique suffer from design flaws, however, creating a bias in favor of the technique (Rizer and Lippy 1993). Variables such as type of prosthesis and oval window seal were not considered. Smyth and Hassard (1978) reviewed 800 stapedectomies, examining the incidence of complications and their relationship with the size of the fenestra created. They reported that, in terms of hearing, the small fenestra technique and the total footplate removal were virtually the same. They found, however, that the small fenestra technique had fewer complications such as perilymph fistula and delayed sensorineural hearing loss. McGee (1981) analyzed 280 stapedectomies and correlated the relationship between fenestra size and improvement of hearing. He reported an improvement in hearing with the small fenestra technique, although his study had many variables, such as different prostheses used for the procedures, different oval window seals, and the amount of footplate removed. Shea (1982) reported better high-frequency hearing and a lower incidence of complications with the small fenestra technique. Moon and Hahn (1984), on the other hand, reported that in their series, although small fenestra stapedectomy improved hearing in the high frequencies, the results did not warrant a change in technique. In their report on hearing results in otosclerosis surgery, Persson et al (1997) compared the findings in patients who had undergone partial stapedectomy, total stapedectomy, and stapedotomy. They examined the hearing results in a consecutive series of 407 patients with otosclerosis who had undergone primary stapes surgery. In all, there were 437 ears that were operated on. Partial stapedectomy was performed on 70 ears (16%), and total stapedectomy was performed on 205 ears (47%). In both groups the House steel wire prosthesis on fascia was used. The remaining 162 ears (37%) had a stapedotomy performed using the Fisch 0.4 mm Teflon platinum piston. Persson et al reported that none of these patients in this series presented with sensori-neural hearing loss (> 15 dB). The comparison between the three groups 1 year postoperatively showed that the air-bone gap was smaller for partial and total stapedectomy than for stapedotomy for all frequencies except at 4 kHz. The air-bone gap was calculated as the difference between the preoperative bone conduction and the postoperative air conduction thresholds. Partial and total stapedectomy also showed larger improvements of bone conduction thresholds compared with stapedotomy for all frequencies except 4 kHz. At the 3-year follow-up, the hearing gain for all frequencies (250 Hz to 8 kHz) was larger for partial and total stapedectomy as compared with stapedotomy. Yet when comparing the decline of hearing from 1 to 3 years postoperatively, the hearing gain achieved with partial and total stapedectomy was much more rapid than with stapedotomy. These results showed that, in the short term, partial or total stapedectomy gives better hearing results even at high frequencies. Stapedotomy, on the other hand, yielded more stable hearing results over time. Persson et al (1997) concluded that, all things considered, good stable hearing results as seen with stapedotomy were preferable to a good initial result, which was likely to deteriorate over time, as seen with partial and total stapedectomy. Spandow et al (2000) conducted a retrospective study where they analyzed the results of 60 stapedectomies with the Schuknecht method, and 55 stapedotomies with the Fisch method. The hearing benefit was maximum 1 year after surgery for both procedures. The improvement of the air conduction thresholds, however, was greater in the stapedotomy procedure than in the stapedectomy group. Both groups maintained significantly improved hearing over a period of 10 years (although thresholds became worse gradually over a period of time). There was just one “dead ear” and two ruptured chorda tympani in the stapedectomy group but none in the stapedotomy group. The authors concluded that stapedotomy with the Fisch-type prosthesis is a safe procedure when performed by an experienced surgeon. Marquet et al (1972) described the surface tension of perilymph to be an important factor in the protection of the labyrinth during surgery upon the footplate. Following stapedectomy, the surface tension of the perilymph, together with the contact angle of the perilymph on the prosthesis, determines the shape of the reparative soft tissue that will close the fenestra. The concave shape of the meniscus protects the labyrinth by preventing foot-plate particles from entering the vestibule. In a small fenestra footplate, particles are very minimal and are less traumatic. This procedure produces complete closure of the air-bone gap in the high frequencies.
Stapedectomy versus Stapedotomy
REVIEW OF THE LITERATURE
RATIONALE FOR USING THE SMALL FENESTRA TECHNIQUE
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