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At least 217 records · Page 12Linked to original sources
PubMed2006

Differences in aerodynamic characteristics of new and dysfunctional Provox 2 voice prostheses in vivo.

Tracheoesophageal voice prostheses need to be replaced due to increased airflow resistance or retrograde leakage of fluid into the trachea as a consequence of biofilm formation. Previous in vitro studies show a change of aerodynamic features of biofilm covered voice prostheses after removal of the prostheses out of the patient. To assess these changes in an in situ situation, aerodynamic characteristics were measured within 45 patients at the beginning and at the end of the wearing process of the Provox 2 voice prosthesis. As a consequence, the influence of biofilm formation on aerodynamic characteristics can be evaluated. In the majority of cases, leakage through the prosthesis was the reason for replacement. No differences were found in the total flow, volume range and intratracheal pressure (ITP) of the voice prostheses measured. The airflow resistance of biofilm covered prostheses was significantly reduced compared to new clean prostheses. However, no correlation was found between the extent of biofilm and the different aerodynamic features measured. Biofilm formation on the Provox 2 is responsible for both reduction in airflow resistance and leakage through the prosthesis by deterioration of the silicone rubber material.

Air Pressure↗
PubMed2004

Long-term retention of endoscopically placed hydrogel prostheses at the lower esophageal sphincter in pigs.

BACKGROUND: Using flexible endoscopic methods, hydrogel prostheses can be safely placed, retained for long periods of time, and removed from the esophageal submucosa of pigs. This new technique may have future applications in the treatment of gastroesophageal reflux disease in selected situations. METHODS: In a controlled, prospective trial, farm pigs ( n = 28) or Sinclair mini-swine ( n = 18) underwent sequential placements of 2-13 pliable, radio-opaque hydrogel prostheses into the submucosa of the esophagus during a single endoscopy session. A novel endoscope-overtube device was used. Followup endoscopy and/or fluoroscopy sessions were video-recorded at 6-week, 12-week, 6-month, and yearly intervals. The endoscopic removal of hydrogels was tested in vivo. Necropsy specimens were inspected for signs of chronic inflammation. RESULTS: Overall, 98% of delivery attempts were successful (288/293). Only three hydrogels were lost after 6 weeks. Short-term animals ( n = 36) retained 88% of hydrogels for periods up to 6 months. Intact hydrogels ( n = 12) were easily removed from four animals at endoscopy. Long-term subjects had two or three hydrogels per animal, using either a beveled-needle device (six pigs) or a trocar design (four pigs). Trocar design: nine of nine prostheses retained at 3 years (100%). Needle design: nine of 10 prostheses retained at 3 years (90%). No significant adverse event occurred. Growth curves were similar between groups. All hydrogels remained pliable to gross inspection upon in vivo removal or necropsy. Pathology showed minimal fibrosis and no chronic inflammation. CONCLUSIONS: A novel endoscopic overtube device allows for the successful delivery of multiple hydrogel prostheses with acceptable safety and long term retention rates. These hydrogel prostheses can also be easily removed from the submucosal space of the esophagus.

Animals↗
PubMed1975

Current status of the Beall, Bjork-Shiley, Braunwald-Cutter, Lillehei-Kaster and Smeloff-Cutter cardiac valve prostheses.

The Starr-Edwards ball valve prosthesis is generally the standard by which other cardiac valve substitutes are compared. This report reviews information pertaining to several prostheses--the Beall mitral valve and the Bjork-Shiley, Braunwald-Cutter, Lillehei-Kaster and Smeloff-Cutter aortic and mitral valves--considered by some to have specific advantages over the Starr-Edwards valves. Hospital and late mortality rates after valve replacement are comparable for the four aortic valve prostheses reviewed and depend more on patient selection than on the specific prosthesis utilized. Extensive clinical experience with the Bjork-Shiley aortic valve indicates that this prosthesis offers hemodynamic advantages over ball valve prostheses, especially in patients with a small aortic root. Clinical experience with the Lillehei-Kaster pivoting disc prosthesis has been less extensive, but this model provides theoretical hemodynamic advantages similar to those of the Bjork-Shiley aortic valve prosthesis. Problems associated with cloth wear and the unexpectedly slow rate, in man, of tissue ingrowth into the fabric of the Braunwald-Cutter aortic valve prosthesis have been discouraging, although this prosthesis has been associated with a very low thromboembolic rate in patients receiving anticoagulant therapy. The Smeloff-Cutter aortic prosthesis is hemodynamically similar to the Starr-Edwards prosthesis and has been proved to be a reliable and durable aortic valve substitute over the past several years. Mortality after mitral valve replacement is also largely influenced by factors other than prosthetic valve design. On the basis of postoperative data, the five mitral valve prostheses reviewed do not appear to have substantial hemodynamic differences. For patients with a small left ventricular cavity the low profile prostheses, such as the Beall, Bjork-Shiley and Lillehei-Kaster, may be advantageous. Most available evidence indicates that patients receiving aortic or mitral valve prostheses should be given anticoagulant therapy postoperatively.

Anticoagulants↗
PubMedDate not supplied

Enhanced healing of 30 microns Gore-Tex PTFE microarterial prostheses by alcohol-pretreatment.

Polytetrafluoroethylene (PTFE) microvascular prostheses with a fibril length of 30 microns were pretreated with alcohol (n = 18), implanted into the abdominal aorta of rats and were evaluated at 1 day (n = 3), 1 week (n = 3), 3 weeks (n = 6) and 6 weeks (n = 6) to determine whether alcohol-pretreatment might improve their healing. Untreated PTFE microvascular prostheses (n = 18) functioned as controls (all prostheses: length 10 mm, I.D. 1.5 mm). The alcohol-pretreated PTFE microarterial prostheses were initially completely filled and covered with clot and showed fast and complete healing within 6 weeks: endothelial cells and smooth muscle cells on the luminal surface, and the interstices filled with fibrous-like tissue. In contrast, the untreated PTFE prostheses were initially not filled or covered with clot and showed only healing near the anastomotic sites and scarce tissue ingrowth into the wall. These results demonstrate that alcohol-pretreatment improves the healing characteristics of PTFE microarterial prostheses with a fibril length of 30 microns. The alcohol-pretreatment renders the PTFE material more accessible to clot and subsequently to cells.

Animals↗
PubMed1993

Healing of microvenous PTFE prostheses implanted into the rat femoral vein.

44 PTFE prostheses (Gore-Tex; ID 1 mm) were implanted into rats' femoral veins by means of the sleeve anastomotic technique and were evaluated at regular intervals from 1 h up till 24 weeks after implantation by means of light and electron microscopy to study in detail their healing process. All prostheses, except one at 1 week and one at 24 weeks after implantation, were patent at the time of removal. Upon implantation, the luminal surface of the prostheses became covered with a thin clot layer. From 1 week onwards, endothelial cells originating from the anastomotic sides grew in across the anastomoses. In addition, small capillary-like orifices were present at the anastomotic sites, from which endothelial cells also seemed to originate. At 2 weeks, in several areas in the mid-region of the prostheses, the fronts of regenerating endothelial cells had reached each other, and about 80% of the luminal surface was covered by endothelium and at 3 weeks, the prostheses were completely covered by an endothelial layer. These results demonstrate that PTFE microvenous prostheses heal exclusively by means of rapid ingrowth of endothelial cells originating from both sides at the anastomoses.

Animals↗
PubMed1993

Expanded polytetrafluoroethylene arterial prostheses in humans: chemical analysis of 79 explanted specimens.

The expanded polytetrafluoroethylene (ePTFE) vascular prostheses are widely used as small and medium diameter blood conduits when an autologous venous material is not available or is not suitable. The long-term performance of a prosthesis is dependent on several factors, including its healing characteristics and its stability in vivo. This study was undertaken to assess whether chemical degradation of ePTFE occurs when such arterial substitutes are implanted in humans. Seventy-nine ePTFE grafts excised for complications were analysed using the following techniques: measurement of the contact angle (theta), electron spectroscopy for chemical analysis (ESCA or XPS), Fourier transform infra-red spectroscopy (FTIR) and differential scanning calorimetry (DSC). The results were compared with those obtained from virgin ePTFE and virgin ePTFE washed prostheses. The measurement of the contact angle (theta) permits the comparison of the level of hydrophobicity of material after in vivo residency. The contact angles of explanted ePTFE grafts are greater than those of virgin ones but remain close to those of washed virgin prostheses. The ESCA method allowed investigation of the chemical changes which occur on the surface of ePTFE prostheses after implantation because of the low penetration of the X-ray (about 50 A). This study did not reveal any chemical degradation of the ePTFE with time of implantation for periods up to 6.5 yr. Changes in the surface composition were probably related to lipid and/or protein uptake. The FTIR spectroscopy provides information about the chemical composition of material. Compared with the virgin ePTFE prostheses, the FTIR spectra of explanted prostheses showed specific bands which are characteristic of lipid and/or protein absorptions. The bulk properties of ePTFE studied by DSC did not show any significant changes with time of implantation. It is concluded that ePTFE grafts remain stable in vivo for periods up to 6.5 yr.

Biocompatible Materials↗
PubMed1992

Regurgitant flow in cardiac valve prostheses: diagnostic value of gradient echo nuclear magnetic resonance imaging in reference to transesophageal two-dimensional color Doppler echocardiography.

Gradient echo nuclear magnetic resonance (NMR) imaging and transesophageal two-dimensional color Doppler echocardiography are flow-sensitive techniques that have been used in the diagnosis and grading of valvular regurgitation. To define the diagnostic value of gradient echo NMR imaging in the detection of regurgitant flow in cardiac valve prostheses and the differentiation of physiologic leakage flow from pathologic transvalvular or paravalvular leakage flow, 47 patients with 55 valve prostheses were examined. Color Doppler transesophageal echocardiography was used for comparison. Surgical confirmation of findings was obtained in 11 patients with 13 valve prostheses. Gradient echo NMR imaging showed regurgitant flow in 37 of 43 valves with a jet seen on transesophageal echocardiography and it detected physiologic leakage flow in 4 additional valves. There was 96% agreement between the two methods in distinguishing between physiologic and pathologic leakage flow. The methods differed on jet origin of pathologic leakage flow in six prostheses. The degree of regurgitation was graded by both NMR imaging and transesophageal echocardiography, according to the area of the regurgitant jet visualized; gradings were identical for 75% of valve prostheses. Quantification of jet length and area showed a good correlation between the two methods (r = 0.85 and r = 0.91, respectively). Gradient echo NMR imaging is a useful noninvasive technique for the detection, localization and estimation of regurgitant flow in cardiac valve prostheses. However, because transesophageal echocardiography is less time-consuming and less expensive, gradient echo NMR imaging is unlikely to displace transesophageal echocardiography and should be used only in the occasional patient who cannot be adequately imaged by echocardiography.

Coronary Circulation↗
PubMed2004

Appropriate radial clearance of ceramic-on-ceramic total hip prostheses to realize squeeze-film lubrication.

OBJECTIVE: Estimation of appropriate radial clearance of ceramic-on-ceramic total hip prostheses to realize squeeze-film lubrication. BACKGROUND: Some clinical results show that severe wear occurs at ceramic-on-ceramic interfaces of total hip prostheses if the design parameters are improper. Appropriate design is required to realize the optimum lubrication of joint prostheses. DESIGN: Squeeze-film thickness of total hip prostheses with different radial clearances was numerically estimated under the physiological conditions of normal walking. METHODS: The changes in the fluid film thickness between ceramic balls and a ceramic cups with radial clearances of various values from 10 to 80 microm were numerically estimated under the assumption of normal walking conditions by means of elastohydrodynamic squeeze-film lubrication theory including the three-dimensional theory of elasticity. RESULTS: The minimum film thickness remained over 0.02 microm during a few walking steps with a radial clearance under 20 microm and a head diameter of 28 mm. On the other hand, the fluid film was squeezed out during a few steps when the radial clearance was greater than 30 microm. CONCLUSIONS: Squeeze-film lubrication can be realized in a ceramic-on-ceramic total hip prosthesis if the radial clearance is smaller than 20 microm on a head of 28 mm diameter. RELEVANCE: Fluid film lubrication is necessary to prevent the severe wear of ceramic joint prostheses. The present investigation shows which radial clearance of ceramic-on-ceramic hip prostheses is appropriate for squeeze-film lubrication under physiological conditions in daily action.

Ceramics↗
PubMed2004

Acoustomechanical properties of open TTP titanium middle ear prostheses.

OBJECTIVE: The purpose of the study was to identify acoustcomechanical properties of various biostable and biocompatible materials to create a middle ear prosthesis with the following properties: (i) improved handling including a good view of the head of the stapes or footplate and adjustable length, (ii) improved acoustical characteristics that are adequate for ossiculoplastic. The identified material should serve to build CE and FDA approved prostheses for clinical use in patients. METHODS: Test models made of Teflon, polyetheretherketone, polyethylenterephtalate, polysulfone, gold, Al2O3 ceramics, carbon and titanium were investigated for their potential to fulfill the requirements. Acoustical properties were investigated by laser Doppler velocimetry (LDV) in mechanical middle ear models (MMM). Measured data were fed in to a recently created computer model of the middle ear (multibody systems approach, MBS). Using computer-aided design (CAD) measured and computed data allowed creation and fine precision of titanium prostheses (Tübingen Titanium Protheses, TTP). Their handling was tested in temporal bones. Acoustomechanical properties were investigated using the MBS and mechanical middle ear models. MAIN OUTCOME MEASURES: Input impedance, mass, stiffness, and geometry of test models and prostheses were determined. Furthermore, their influence on the intraprosthetic transfer functions and on coupling to either tympanic membrane or stapes was investigated. RESULTS: Final results were FDA- and CE-approved filigreed titanium prostheses with an open head that fulfilled the four requirements detailed above. The prostheses (TTP) were developed in defined lengths of between 1.75 and 3.5 mm (partial) and 3.0 and 6.5 mm (total) as well as in adjustable lengths (TTP-Vario). CONCLUSIONS: The results suggest acoustomechanical advantages of TTPs because they combine a significantly low mass with high stiffness. In contrast to closed prostheses, the open head and filigreed design allow an excellent view of the prosthesis foot during coupling to the head or footplate of stapes, contributing to an improved intraoperative reliability of prosthesis coupling.

Acoustics↗
PubMed2006

Performance of bioprostheses and mechanical prostheses assessed by composites of valve-related complications to 15 years after aortic valve replacement.

OBJECTIVE: This study was conducted to compare the composites of valve-related complications, namely reoperation, morbidity (defined as permanent neurologic or other functional impairment), and mortality, between bioprostheses and mechanical prostheses for aortic valve replacement. METHODS: Between 1982 and 1998, 2195 bioprostheses were implanted in 2179 patients and 980 mechanical prostheses were implanted in 883 patients. Total follow-up was 16,442 years and 5740 years for bioprostheses and mechanical prostheses, respectively. Eight variables were considered as predictors of risk for the composites of valve-related complications. RESULTS: Linearized rates for valve-related reoperation were 1.3%/patient-year and 0.3%/patient-year for bioprostheses and mechanical prostheses (P < .001), respectively. All age groups were differentiated, except >70 years. Valve-related morbidity was differentiated for all age groups and overall, for bioprostheses and mechanical protheses, was 0.4 %/patient-year and 2.1%/patient-year, respectively (P < .001). Overall valve-related mortality was 1.0%/patient-year for bioprostheses and 0.7%/patient-year for mechanical prostheses (P = .018). Age and valve-type were predictive risk factors for reoperation and morbidity, whereas age alone was predictive of mortality. Actual freedom from valve-related reoperation favored mechanical prostheses for all age groups, except 61-70 years and >70 years. Actual freedom from valve-related morbidity favored bioprostheses in all age groups, except < or =40 years. Actual freedom from valve-related mortality was undifferentiated in patients 51-60, 61-70, and >70 years. CONCLUSION: No differences were observed in valve-related reoperation and mortality in patients >60 years. Comparative evaluation gives high priority for bioprostheses in patients >60 years based on improved morbidity profile. This evaluation extends this center's recommendation for bioprostheses in aortic valve replacement to include patients >60 years.

Adolescent↗
PubMed2004

In vitro comparative analysis of the fit of gold alloy or commercially pure titanium implant-supported prostheses before and after electroerosion.

STATEMENT OF PROBLEM: For implant-supported prostheses, passive fit is critical for the success of rehabilitation, especially when alternative materials are used. PURPOSE: The purpose of this study was to compare interfacial fit of implant-supported prostheses cast in titanium to those cast in gold alloy. MATERIAL AND METHODS: Five 3-unit fixed partial dentures were fabricated in gold alloy (Degudent U) as 1-piece castings, and 5 others were similarly cast in commercially pure titanium (Grade 1). The interfacial gaps between the prostheses and the abutments were evaluated with an optical microscope, before and after electroerosion. Readings were made with both screws tightened (10 N.cm torque), and with only 1 side tightened, so as to also evaluate the passive fit of the prostheses. Data were compared statistically by 2-way analysis of variance and the post hoc Tukey multiple range test (alpha=.05). RESULTS: Before electroerosion, the interfacial gaps for the 1-piece prostheses were significantly smaller (P<.001) in the gold alloy group when the screws were tightened (Au=12.6 +/- 3.0 microm, compared to Ti=30.1 +/- 6.4 microm). When the side opposite the tightened side was analyzed, there was no significant difference between the gold alloy and titanium groups (Au=69.2 +/- 24.9 microm and Ti=94.2 +/- 39.6 microm). The electroerosion procedure significantly (P<.001) reduced the gaps at the interfaces for both groups under all conditions. Comparison between groups after electroerosion did not present significant differences when the side opposite the tightened side was analyzed, but the gold alloy group showed better fit when the tightened side was analyzed (12.8 +/- 1.4 microm for gold alloy; 29.6 +/- 4.4 microm for titanium) and when both screws were tightened (5.4 +/- 2.3 microm for gold alloy; 16.1 +/- 5.5 microm for titanium). CONCLUSIONS: Cast titanium prostheses, despite showing larger interfacial gaps between the prosthesis and abutment than those obtained with gold alloy, had improved fit after being subjected to electroerosion.

Analysis of Variance↗
PubMed1999

Patient-prosthesis mismatch is negligible with modern small-size aortic valve prostheses.

BACKGROUND: Concern has been raised about residual significant gradients when small aortic prostheses are used, particularly in patients with large body surface areas. We studied the performance of six types of small aortic prostheses using dobutamine stress echocardiography. METHODS: Sixty-three patients (mean age, 67 +/- 7 years) who had undergone aortic valve replacement 17 +/- 6 months previously were studied. Two bileaflet mechanical prostheses (St. Jude Medical and CarboMedics: sizes, 19 mm and 21 mm) and two biological prostheses (Medtronic Intact and St. Jude BioImplant: size, 21 mm) were evaluated. A graded infusion of dobutamine was given and Doppler studies of valve performance were carried out. RESULTS: All prostheses except one biological valve had acceptable hemodynamic performance under stress. Using regression modeling, gradient at rest was the only variable found to predict gradient under stress (p < 0.001). Moreover, the most important predictor of gradient at rest was valve design, which accounted for 72% of the variance (p < 0.001). This relationship was independent of valve size (19 mm or 21 mm) or material (ie, mechanical or biological). Body surface area accounted for 4% of the variance in gradient only. CONCLUSIONS: The main predictor of transprosthetic gradient is the inherent characteristics of each particular prosthesis, with relatively insignificant contribution from variations in body surface area. Patient-prosthesis mismatch is not a problem of clinical significance when certain modern valve prostheses are used.

Aged↗
PubMed1997

Individual prostheses and resection templates for mandibular resection and reconstruction.

This new technique uses helical computed tomography data and computer-aided design and manufacturing for preoperative fabrication of individual mandibular prostheses together with corresponding resection templates. Coherent 3D geometries for computer-based models are the basis for the construction of prostheses and provide data for a computerized numerical control fabrication. Fixation plates are fabricated with the titanium prostheses. The identical data of these plates are used for the computer-aided design and manufacturing of resection templates, which guide an oscillating saw in a precisely determined resection plane. This plane again is identical with the prostheses' margins for mandibular body replacement. The use of this technique in four patients is reported on: after temporary insertion of the templates for resection and after resection, the prostheses were stabilized with the same screws in the same screw-holes where the templates had been. Resection and reconstruction were thus highly precise, safe and fast and primarily led to excellent aesthetic and functional results. Wound-healing depends on a safe soft-tissue reconstruction over these large prostheses. Coverage with flaps seems obligatory. In spite of the superior technical aspects, the clinical long-term results of this new technique were poor.

Adult↗
PubMed2003

Within-subject comparisons of maxillary fixed and removable implant prostheses: Patient satisfaction and choice of prosthesis.

Dental implants provide patients with restorative options for the edentulous maxilla. Both fixed and removable prostheses can be attached to the edentulous maxilla, but the efficacy of different designs has not been determined. In this two-session within-subject crossover trial we compared maxillary implant retained fixed prostheses with removable implant overdentures opposed by mandibular implant-supported overdentures. Sixteen patients, who had previously received mandibular implants, entered the study and received four to six maxillary implants. After dropouts as a consequence of a lack of osseointegration and general health problems, 13 remained. Of these, five received the removable prosthesis first and eight the fixed prosthesis. After 2 months, the prostheses were exchanged and the second was also worn for 2 months. Psychometric measurements of general satisfaction with the prostheses as well as comfort, ability to speak, stability, esthetics, ease of cleaning and occlusion were obtained once each prosthesis had been worn for 2 months. Chewing ability was assessed for seven types of food. Removable long-bar overdentures received significantly higher ratings of general satisfaction than fixed prostheses (P = 0.003). Patients also rated their ability to speak and ease of cleaning significantly better with the removable overdentures. Nine patients chose to keep the removable prosthesis and four preferred to keep the fixed prosthesis. The results suggest that maxillary removable overdentures on multiple implants may provide patients with better function than fixed prostheses.

Attitude to Health↗
PubMed1997

Complications and maintenance requirements of implant-supported prostheses provided in a UK dental hospital.

AIM: To assess the nature, timing and frequency of complications associated with implant therapy and to assess maintenance requirements of implant-supported prostheses. DESIGN: Retrospective analysis. SETTING: The Dental Hospital in Newcastle upon Tyne. METHOD: Dental records of 60 patients provided with implant-supported prostheses were examined. Data were compiled on the number of fixtures placed per patient, the type of prosthesis provided, complications during the surgical and prosthodontic phases, and peri-implant soft tissue complications. RESULTS: 66 prostheses were placed on 236 fixtures over a 6-year period. Surgical complications included fixture loss (n = 6), dysaesthesia (n = 12), and the need for a guided tissue regeneration procedure (n = 10). Common maintenance requirements were tightening of components (n = 11), clip replacement (n = 7) and repair of conventional prostheses opposing implant supported prostheses (n = 7). Plaque control was unsatisfactory with almost half of the subjects requiring intensive oral hygiene instruction and scaling at the first post placement review. CONCLUSIONS: Prosthodontic maintenance requirements were high, particularly during the first year. Surgical complications were relatively infrequent. A case was made for a rigorous oral hygiene programme to reduce the potential for fixture loss through neglect. The financial cost associated with the maintenance of implant-supported prostheses should be incorporated in their overall funding.

Dental Clasps↗
PubMed1996

Penile prostheses in paraplegic men.

OBJECTIVES: To determine the efficacy of penile prostheses in paraplegic men. PATIENTS AND METHODS: Between 1980 and 1992, penile prostheses were implanted in 209 paralysed men of whom the records of 179 were evaluable. The indication for implantation was erectile dysfunction, penile retraction, or a combination of the two. RESULTS: The outcome of the implantation of semi-rigid prostheses was worse than that of semi-flexible or flexible prostheses. Antibiotic treatment and body disinfection reduced the infection rate to below that in a normal population. The results were satisfactory for patients with either problem and patients treated successfully for erectile dysfunction became more self-confident. CONCLUSIONS: When paraplegic patients are able to regain sexual activity after successful implantation of a penile prosthesis, their self-confidence is increased. Prostheses might also be useful for patients who will not accept self-injection and for those using external condom drainage. Penile prostheses clearly have a place in the treatment of paralysed men.

Adolescent↗
PubMed2000

Sister chromatid exchange in patients with joint prostheses.

The evaluation of sister chromatid exchanges (SCE) is used to establish the cytogenic damage in subjects exposed to toxic substances. The test is considered to be 1 of the most sensitive and accurate indicators of damage and responds to toxic chemicals at low doses. We evaluated the incidence of SCE in peripheral lymphocytes of patients with articular prostheses. Subjects with prostheses made of titanium-aluminium-vanadium alloys presented a significantly higher SCE number than the control population (6.3+/-2.3 vs 4.4+/-1.3; P = .0128), whereas subjects with prostheses made of chrome-cobalt alloy or mixed prostheses presented a higher SCE value than the controls but not significantly different. The presence of high-frequency cells was alarming only in 5 patients, 4 of whom had titanium alloy prostheses, whereas none belonged to the control group. The number of SCE was not affected by the presence of bone-cement used in prosthesis fixation or by the implant duration. The indication of possible cytogenic damage in patients with titanium alloy prostheses that emerged from this study should be considered carefully, even though the sample population was small.

Adult↗
PubMed2000

Evaluation of hydroxyapatite ossicular chain prostheses.

Hydroxyapatite (HA) middle ear prostheses have gained popularity as an alternative to human autografts and homografts. This study reports on 3 HA prostheses types: total ossicular chain prostheses, used for grafting the stapes footplate to the tympanic membrane; partial ossicular chain prostheses, used for grafting the stapes superstructure to the tympanic membrane; and Kartush incus struts (Smith & Nephew Richards Inc), used for grafting the stapes superstructure to the undersurface of the malleus. This single-surgeon study of 33 consecutive cases revealed a statistically significant difference in mean postoperative air-bone gap and airbone gap closure between incus struts (14/26 dB) or partial (22/11 dB) or total (25/10 dB) ossicular chain prostheses (t test: P<0.05). Prognostic risk factors graded by the Middle Ear Risk Index indicate a tendency for worse postoperative hearing with increasing Middle Ear Risk Index. This study supports the use of HA ossicular prostheses and, in particular, the use of the malleus for ossicular chain construction.

Adult↗