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Page/Link:Page URL:HTML link:The Free Library. Retrieved Sep 06 2019 fromAbstractWe conducted a retrospective study to compare poststapedectomyhearing gain in study-eligible patients who had received a Teflon(fluoroplastic ASTM F 754) prosthesis (study group; n = 76) with hearinggain achieved in a matched group (by age, sex, and degree of hypoacusis)of patients who had received a Schuknecht-type wire/Teflon prosthesis(control group; n = 70).
All procedures had been performed by theauthors at our institution between Jan. 2, 1994, and Dec.
31, 1997.Airway averages at low, medium, and high frequencies were estimated onthe basis of pre- and postoperative audiologic evaluations, as weretotal air-bone gaps at 7 frequencies between 125 and 8,000 Hz. We foundthat the study group achieved a significantly greater degree of hearinggain at 125 and 250 Hz and significantly better closure of the air-bonegap at 250, 500, 1,000, 2,000, and 4,000 Hz. The hearing outcomes amongpatients in the study group were excellent.IntroductionOtosclerosis, an osteodystrophy limited to the temporal bone (oticcapsule), can cause a progressive conductive hearing loss (andoccasionally a sensorineural hearing loss if the cochlea is involved).(1) The treatment of patients with otosclerosis and associatedconductive hearing loss is stapedectomy. In 1956, Shea performed thefirst stapedectomy, which involved a complete removal of the stapes andclosure of the oval window with a vein graft; hearing gain was achievedby placing a polyethylene strut to connect the incus to the vein graft.(2). Since then, Shea's technique has been modified several times.(3) Shea abandoned the use of the polyethylene prosthesis because it hada tendency to slide toward the vestibule and erode the incus. In 1960,Schuknecht and Oleksiuk introduced a wire prosthesis. (4) A Gelfoam wireprosthesis was also used during the 1960s, but it too was abandonedafter it became implicated in an increase in the incidence ofsensorineural hearing loss and in the risk of postoperativeperilymphatic fistulae.The 1970s marked the beginning of the era of the metal-wire andTeflon (polytetrafluoroethylene) Schuknecht-type piston prosthesis ofvarious diameters (0.4, 0.6, and 0.8 mm).
On the water surface the teflon/platinum and the teflon/steel pistons adjusted their direction with their axis longitudinally to the MRI scanner opening and the teflon/steel piston floated towards the MRI-machine when put close enough to the scanner opening. No rise in temperature was recorded. Audio Technologies stapes implants. Audio Technologies stapes pistons are finely manufactured to grant the surgeon the maximum easy-handling, reliability and safeness. The unique features are the result of 40 years of manufacturing experience and continuous experimentations and updates made by the author and by all of our clients.
The diameter of the mostwidely used wire/Teflon prosthesis is 0.6 mm. During surgery, the wireis fixed to the long arm of the incus and manually closed with a McGeeforceps. (5,6) Improper closure of the wire was reported to causeerosion and necrosis of the incus arm in 43.2% of cases. (6-9) Perkinsand Curto reported that the use of the wire/Teflon prosthesis resultedin a closure of the air-bone gap of 16.1, 7.9, 3.9, and 10.2 dB at 500,1,000, 2,000, and 4,000 Hz, respectively. (10) Closure of the air-bonegap to within 10 dB has been reported in as many as 82.8% of patients.(10,11)Since 1995, we have been using the fluoroplastic ASTM F 754prosthesis, which is made completely of Teflon. To ensure correctplacement intraoperatively, the prosthesis ring is opened with a set ofcupped tweezers or a hooked instrument. The prosthesis remains open forseveral minutes, which allows for its proper placement before memorycloses it.In this article, we describe our comparison of the Teflonprosthesis with the wire/Teflon device in terms of postoperative hearinggain.
To the best of our knowledge, no such study has heretofore beenpublished in the world literature.Patients and methodsWe retrospectively reviewed the records pertaining to allstapedectomies that we performed between Jan. 2, 1994, and Dec. 31,1997, at the Otorhinolaryngology-Head and Neck Surgery Service at Dr.Gaudencio Gonzalez Garza General Hospital, an otologic tertiary carecenter in Mexico City. In order to be eligible for this study, cases hadto have involved (1) patients of either sex who were between 17 and 60years of age, (2) clinically diagnosed and audiologically corroborated otosclerosis, (3) a 65-dB conductive hypoacusis with tone loss, and (4)stapedectomy with placement of either a Teflon prosthesis or awire/Teflon prosthesis. The groups were paired by age, sex, and degreeof hypoacusis. We excluded cases in which patients had had ossicular chain fixation secondary to tympanic sclerosis, malleus and incusproblems, or congenital anomalies. All of the authors had used the samesurgical technique to perform all stapedectomies.
Local anesthesia wasadministered in every case. Once all eligible charts had been selected, we reviewed them foreach patient's age, sex, degree of hypoacusis, and type ofprosthesis. We also reviewed audiologic data and noted airway averagesat low frequencies (125,250, and 500 Hz), medium frequencies (500,1,000, and 2,000 Hz) and high frequencies (2,000, 4,000, and 8,000 Hz).We also noted air-bone gaps at 0, 1 to 5, 6 to 10, 11 to 15, 16 to 20,and 21 to 25 dB at low (250 and 500 Hz) and high (1,000, 2,000, and4,000 Hz) frequencies as recorded by a Madsen Midimate 602 audiometer (GN Otometrics; Taastrup, Denmark).The statistical analysis was done with the assistance of SPSS 8.0software (SPSS; Chicago). Frequency measures were used independently foreach of the variables. For qualitative variables such as sex, thechi-square test was used. Based on the skewness and kurtosis values, weused the Mann-Whitney U test and the Student's t test to analyzegroup differences.ResultsOf the 436 cases we reviewed, 146 met our inclusion criteria.
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Thesecases involved 76 patients who had received a Teflon prosthesis (studygroup) and 70 who had received a wire/Teflon prosthesis (control group).The two groups were paired according to age, sex, and the degree ofhearing loss; there were no statistically significant differencesbetween the groups in these variables (table 1).Analysis of postsurgical hearing gain in both groups revealed astatistically significant difference (p.