[Efficacy observation of auditory reconstruction using three different materials in ossiculoplasty and mastoidectomy to treat chronic otitis media].

OBJECTIVE: To study the effects of different types of prosthesis used in ossiculoplasty on mastoidectomy of treating chronic otitis media. METHOD: One hundred and forty three patients with chronic otitis media were treated by canal wall-down tympanoplasty with ossiculoplasty in a single stage. According to material of prosthesis, they were classified as titanium group (group A, 52 cases), hydroxypatite group (group B, 47 cases) and autogenous bone group(group C, 44 cases). The postoperative complication and hearing thresholds were analyzed in the 24 months follow-up. Average postoperative air-conduction gain and air-bone gap were measured at four frequencies: 0.5, 1.0.2, and 4.0 kHz. RESULT: 12-month after operation, the average air threshold and air-bone gaps of the three groups were reduced (P < 0.05). The reconstruction successful rate (78.7%) of group A was slightly better than that of B, C (68.1%, 70.4%), there was no statistically significant difference. The difference of the average air threshold and air-bone gaps of group B, C after 24-month of operation and 12-month after operation was statistically significant (P < 0.05). The reconstruction successful rate (48.9%, 45.5%) of group B, C was lower than that of A (76.9%), the difference was also statistically significant (P < 0.05). CONCLUSION: Prostheses using titanium type could give good functional results and strong stability with low complication.

[Active middle-ear implants]. / Tipos de implantes activos de oído medio.

Active middle ear implants are classified as piezoelectric implants, which use the properties of piezoelectric materials. There are two types of piezoelectric implants: monomorphic and dimorphic; electromagnetic transduction uses a magnet, usually a rare earth magnet (e.g. samarium cobalt) and an energizing coil. This magnetic field causes the magnet to vibrate, which in turn, through the tympanic-ossicular chain, causes movement of the cochlear fluids. Electromechanical transduction is a variation of electromagnetic transduction.

Tipos de implantes activos de oído medio / Active middle-ear implants

Los implantes activos de oído medio se clasifican en implantes piezoeléctricos, que utilizan las propiedades de los materiales piezoeléctricos, y son de dos tipos: monomorfos y dimorfos, y en implantes de transducción electromagnética: se utiliza un imán, generalmente de tierras raras (p. ej., samario cobalto), y una bobina inductora. Este campo magnético provoca la vibración del imán, que al estar acoplado directamente a la cadena tímpano-osicular pone en movimiento los fluidos cocleares. La transducción electromecánica es una variación de la electromagnética (AU)

Active middle ear implants are classified as piezoelectric implants, which use the properties of piezoelectric materials. There are two types of piezoelectric implants: monomorphic and dimorphic; electromagnetic transduction uses a magnet, usually a rare earth magnet (e.g. samarium cobalt) and an energizing coil. This magnetic field causes the magnet to vibrate, which in turn, through the tympanic-ossicular chain, causes movement of the cochlear fluids. Electromechanical transduction is a variation of electromagnetic transduction (AU)

[Does the material of stapes prosthesis influence hearing improvement in stapes surgery--retrospective analysis of 350 cases]. / Wplyw rodzaju protezki strzemiqczka na stopien poprawy sluchu w chirurgii strzemiaczka--analiza retrospektywna 350 przypadków.

AIM: Retrospective analysis of the post-op hearing results in stapes surgery using different types of materials for stapes prosthesis after 12 months follow up. MATERIAL AND METHODS: The total number of 350 otosclerosis patients who underwent surgical treatment at the Otosurgery Department, Medical University of Lodz from 1980-2002. All patients included in the study were divided into 4 groups: group 1 (N=54)--Portmann's method interposition, group 2 (N=160)--stapes replaced with the Shea-type prosthesis, group 3 (N=60)--platinum wire prosthesis (Zini-type), group 4 (N=76)--teflon-piston operation (Fisch-type). RESULTS: The 12 months post-op mean value for air-bone gap (500, 1000, 2000 Hz) presented the following values: group 1-19 dB, group 2-15.9 dB, group 3-18.4 dB, group 4-13.5 dB. The percentage of patients with the mean air-bone gap value of 15 dB or less (500, 1000, 2000 Hz) has the following values in each group: group 1-75%, group 2-81.3%, group 3-83%, group 4-85%. CONCLUSIONS: 12 months post-op hearing results compared between the 4 studied groups showed statistically not significant differences. Our experience with teflon-piston prosthesis shows the lowest post-op mean value of the air-bone gap.

Magnetic resonance imaging of stapes prostheses.

OBJECTIVE: To assess the magnetic resonance imaging (MRI) compatibility of stapes prostheses. DATA SOURCES: A comprehensive review of the English literature evaluating MRI compatibility of stapes prostheses. Multiple series of stapes prostheses from different manufactures placed in a 1.5-tesla MRI field to determine ferromagnetic properties. RESULTS: When MRI was first introduced, reports demonstrated the MRI compatibility of stapes prostheses. The testing was performed on single copies of various prostheses from several manufacturers. Although implant manufacturers have indicated MRI compatibility, several reports of variable ferromagnetic properties of aneurysm clips have been reported. This variability has led to rotation of the clips and hemorrhage in patients with supposed MRI-compatible clips. These findings suggest that testing single stapes prostheses from a manufacturer might not completely assess the safety of MRI on patients with stapes prostheses. We performed MRI compatibility testing on several series of stapes prostheses from Xomed Surgical Products and Smith & Nephew Richards. Two series of Xomed stapes prostheses were found to have ferromagnetic properties. CONCLUSION: Manufacturing variability could lead to stapes prostheses being MRI incompatible. Each prosthesis should be tested before implantation for ferromagnetic properties.