Patellar instability in total knee arthroplasty.
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Aged↗
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Results for “Prosthesis Fitting”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Complication of cochlear implantation surgery.
After experiencing gradual, progressive sensorineural hearing loss, a patient underwent cochlear implant (CI) surgery. Postoperatively, the patient experienced vestibular symptoms with no improvement in hearing. High-resolution temporal bone CT scanning demonstrated extracochlear positioning of the CI electrode in the superior semicircular canal.
Aged↗
[Effects of investment materials on cast shrinkage of base metal alloys].
OBJECTIVE: To compare the influence of different investment materials, methods and crown height on the cast shrinkage of full crowns made of dental base metal alloy. METHODS: All of the 288 wax patterns were made and divided into three groups according to their crown height. In every group, wax patterns were invested in metal rings and paper rings with three types investment material and cast with base metal alloys. Then the inside diameters of castings were measured and analyzed by statistical package SPSS. RESULTS: Differences between groups invested with the three types of material were significant(P < 0.01). There were significant difference between the groups investing with metal rings and paper rings(P < 0.01). CONCLUSION: The component of investment material and invested ring can affect the cast shrinkage of dental base metal alloy apparently.
Crowns↗
Acoustic analysis of speech through a hearing aid: perceptual effects of changes with two-channel compression.
Compression amplification significantly alters the acoustic speech signal in comparison to linear amplification. The central hypothesis of the present study was that the compression settings of a two-channel aid that best preserved the acoustic properties of speech compared to linear amplification would yield the best perceptual results, and that the compression settings that most altered the acoustic properties of speech compared to linear would yield significantly poorer speech perception. On the basis of initial acoustic analysis of the test stimuli recorded through a hearing aid, two different compression amplification settings were chosen for the perceptual study. Participants were 74 adults with mild to moderate sensorineural hearing impairment. Overall, the speech perception results supported the hypothesis. A further aim of the study was to determine if variation in participants' speech perception with compression amplification (compared to linear amplification) could be explained by the individual characteristics of age, degree of loss, dynamic range, temporal resolution, and frequency selectivity; however, no significant relationships were found.
Aged↗
[Acoustic perception in patients using a cochlear implant before and after adjustment sessions].
The aim of the study was comparison of perception of pure tones and speech intelligibility in postlingually deaf patients using a cochlear implant before and after elective adjustment sessions. 10 patients were examined: 5 children (age 8-15.5 years) and 5 adults with cochlear implants NUCLEUS CI22 (6 patients) and NUCLEUS CI24 (4 patients) produced by COCHLEAR (Australia). It was found that between the adjustment sessions all the implanted patients showed deteriorated perception of pure tones throughout all the frequencies and therefore their speech intelligibility worsened. The recommended period between the adjustments is 6 months as acoustic perception degraded with time. However, such observations are not significant in view of insufficient material. Objective assessment of acoustic perception is necessary because subjective sensations are not always true.
Adolescent↗
Calibrated portacaval H-graft shunt in variceal hemorrhage. Long-term results.
BACKGROUND/AIMS: To analyze the long-term outcome of the calibrated portacaval shunt in the treatment of portal hypertension. METHODOLOGY: Between 1991 and 1996 we undertook a prospective non-randomized study, including 37 cirrhotic patients who underwent small diameter portacaval shunt with polytetrafluoroethylene H-graft, 24 cases with 8 mm and 13 cases with 10 mm. Early and late complications, and survival were analyzed. RESULTS: Overall, 28 corresponded to Child-Pugh class A, 5 to class B and 4 to class C. The cause of cirrhosis was alcoholic in 16 cases, postnecrotic in 12, mixed in 5, primary biliary cirrhosis in 2 and unknown in 1. Postoperative mortality was 10%. Long-term results, after a follow-up of 3-8 years, have shown a rebleeding rate of 12%, mainly after the third postoperative year. Some degree of encephalopathy occurred in 23% of the patients, but in no case was this chronic or incapacitating. The rate of early thrombosis was 5%, but in all cases it was repermeabilized with local thrombolysis. The late thrombosis rate was 6%. The 3-, 5- and 7-year survival rates were 79%, 57%, and 36%, respectively. These rates were not statistically related with the shunt diameter or the etiology of the cirrhosis. CONCLUSIONS: Partial portacaval shunt is a safe option for the treatment of variceal bleeding due to portal hypertension. We consider it to be the treatment of choice in a selected group of cirrhotic patients with well-preserved liver function, after previous failure of medical therapy. Furthermore, it can also be used as a bridge until liver transplantation.
Adult↗
Turn-up bone flap for lengthening the below-knee amputation stump.
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Amputation Stumps↗
Light-adjustable lens.
PURPOSE: First, to determine whether a silicone light-adjustable intraocular lens (IOL) can be fabricated and adjusted precisely with a light delivery device (LDD). Second, to determine the biocompatibility of an adjustable IOL and whether the lens can be adjusted precisely in vivo. METHODS: After fabrication of a light-adjustable silicone formulation, IOLs were made and tested in vitro for cytotoxicity, leaching, precision of adjustment, optical quality after adjustment, and mechanical properties. Light-adjustable IOLs were then tested in vivo for biocompatibility and precision of adjustment in a rabbit model. In collaboration with Zeiss-Meditec, a digital LDD was developed and tested to correct for higher-order aberrations in light-adjustable IOLs. RESULTS: The results establish that a biocompatible silicone IOL can be fabricated and adjusted using safe levels of light. There was no evidence of cytotoxicity or leaching. Testing of mechanical properties revealed no significant differences from commercial controls. Implantation of light-adjustable lenses in rabbits demonstrated- excellent biocompatibility after 6 months, comparable to a commercially available IOL. In vivo spherical (hyperopic and myopic) adjustment in rabbits was achieved using an analog light delivery system. The digital light delivery system was tested and achieved correction of higher-order aberrations. CONCLUSION: A silicone light-adjustable IOL and LDD have been developed to enable postoperative, noninvasive adjustment of lens power. The ability to correct higher-order aberrations in these materials has broad potential applicability for optimization of vision in patients undergoing cataract and refractive surgery.
Animals↗
Preclinical hemodynamic assessment of a new trileaflet mechanical valve in the aortic position in a bovine model.
BACKGROUND AND AIM OF THE STUDY: The hemodynamic characteristics of a new trileaflet mechanical heart valve (TTV) (TriFlo Inc., Costa Mesa, CA, USA) in the aortic position were evaluated in a bovine model. The TTV was designed to combine the durability of mechanical heart valves with the central flow characteristics of a bioprosthesis. METHODS: Using nine calves, the native aortic valve was replaced with a 21-mm TTV (n = 6) or a St. Jude Medical (SJM) valve (n = 3). Hemodynamic values were assessed with echocardiography at implantation and with catheterization at explantation. All calves underwent a necropsy, followed by gross pathology and light microscopy studies. RESULTS: The mean implant duration was 159 +/- 55 days for the TTV and 102 +/- 67 days for the SJM valve. Immediately before euthanasia, the peak and mean pressure gradients were respectively 35 +/- 14 and 24 +/- 9 mmHg for the TTV, and 100 +/- 72 and 59 +/- 38 mmHg for the SJM valve (p = 0.03). Two of the SJM-valve animals were electively sacrificed after showing symptoms of aortic stenosis. At necropsy, all nine valves were free from thrombi, pannus, occlusive tissue, or mechanical impairment of leaflet motion. The prematurely sacrificed SJM-valve animals had concentric myocardial hypertrophy consistent with severe functional aortic stenosis. CONCLUSION: The significantly higher gradients and left ventricular hypertrophy in the SJM-valve animals were related to a smaller effective orifice area, which precluded adaptation to increasing transvalvular volumes in the growing animal. This problem was not seen with the TTV, which performed hemodynamically as well as the SJM valve. The high transvalvular gradients seen with the SJM valve at study end may suggest that the hemodynamic characteristics of the TTV may be superior, though additional studies are needed to confirm this.
Animals↗
Effectiveness of single detachable COOK coils in closure of the patent ductus arteriosus.
OBJECTIVE: To assess the efficacy and safety of single detachable coils in the closure of PDAs. METHODS: Review of cases in which a single detachable coil was implanted. The diameter of the ampulla was used to select coil size. Diameters of the PDA, ampulla and residual shunts were measured. RESULTS: There were 36 patients with a mean minimal ductal diameter of 2.2 +/- 0.6 mm. Immediately after implantation, 46% of the patients had residual shunts and after 24 hours, only 28%. A final spontaneous closure rate of 94% was observed after 21 months. There was a significant (p < 0.01) difference when minimal PDA diameter of those who had complete closure within 24 hours (median: 2 mm, interquartile range: 1.7-2.3 mm) was compared to those with a residual shunt (median: 2.5 mm, interquartile range: 2.3-3.2 mm). Negligible complications were experienced. CONCLUSIONS: Single Cook detachable coils are effective for PDA closure with a low complication rate if properly selected. There is a high rate of spontaneous closure of trivial residual shunts. In patients with a minimal ductal diameter > or = 2 mm and a residual shunt, more coils may be considered.
Adolescent↗
Bone anatomy and rotational alignment in total knee arthroplasty.
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Arthroplasty, Replacement, Knee↗
[Multi-channel cochlear implants in patients with Mondini malformation].
OBJECTIVE: To describe clinical experiences with multi-channel cochlear implantation in patients with Mondini malformation. METHODS: Among 300 patients who received multi-channel cochlear implants from 1996 to 2002 in Beijing Tongren Hospital, 15 patients were diagnosed with Mondini malformation. A retrospective analysis was performed dealing with the surgical techniques, mapping and rehabilitations characteristics after surgery. 15 patients with normal cochlear structure are consider as control group. RESULTS: Gusher is found more common than the normal cochlear implantation, most of them are serious. The electrodes are inserted in the "cochleostomy" in full length of 13 Patients, 2 pairs of electrodes remains outside of "cochleostomy" in 2 patients. No serious complications occurred after implantation. All patients have auditory sensations. The impedance of the electrodes, the T level, C level and the hearing threshold are similar with the normal cochlear implantation group. The results have no significant difference in compare with normal cochlear group(P > 0.05). CONCLUSION: Multi-channel cochlear implantation could be performed safely in patients with Mondini malformation. The primary outcome for patients with Mondini malformation are similar to those with normal cochlear structure following the multi-channel cochlear implantation.
Adolescent↗
Acetabular position setting in total hip arthoplasty by using V-inclinometer.
The abduction angle of the acetabular implant position is important in the process of total hip arthroplasty. The authors evaluated the potential benefit of a V-inclinometer in the prediction of the abduction angle. To evaluate the accuracy of the V-inclinometer, acetabular cups were inserted in 50 cadaveric pelvises. The abduction angle from V-inclinometer and digital photograph were compared and analyzed using paired t-test. There was no statistical difference of the acetabular abduction angle between digital photograph and V-inclinometer (P > 0.05). The V-inclinometer can be used to predict the abduction angle on a cadaveric pelvis, suggesting that it could be a useful adjunct in clinical practice.
Acetabulum↗
The effective orifice area/patient aortic annulus area ratio: a better way to compare different bioprostheses? A prospective randomized comparison of the Mosaic and Perimount bioprostheses in the aortic position.
BACKGROUND AND AIM OF THE STUDY: The aim of this prospective, randomized study was to compare the hemodynamic performance of the Medtronic Mosaic and Edwards Perimount bioprostheses in the aortic position, and to evaluate prosthesis-specific differences in valve sizing and valve-size labeling. METHODS: Between August 2000 and September 2002, 139 patients underwent isolated aortic valve replacement (AVR) with the Mosaic (n = 67) or Perimount (n = 72) bioprosthesis. Intraoperatively, the internal aortic annulus diameter was measured by insertion of a gauge (Hegar dilator), while prosthesis size was determined by using the original sizers. Transthoracic echocardiography was performed to determine hemodynamic and dimensional data. As the aim of AVR is to achieve a maximal effective orifice area (EOA) within a given aortic annulus, the ratio of EOA to patient aortic annulus area was calculated, the latter being based on annulus diameter measured intraoperatively. RESULTS: Operative mortality was 2.2% (Mosaic 3.0%; Perimount 1.4%; p = NS). Upsizing (using a prosthesis larger in labeled valve size than the patient's measured internal aortic annulus diameter) was possible in 28.4% of Mosaic patients and 8.3% of Perimount patients. The postoperative mean systolic pressure gradient ranged from 10.5 to 22.2 mmHg in the Mosaic group, and from 9.4 to 12.6 mmHg in the Perimount group; it was significantly lower for 21 and 23 Perimount valves than for 21 and 23 Mosaic valves. The EOA ranged from 0.78 to 2.37 cm2 in Mosaic patients, and from 0.95 to 2.12 cm2 in Perimount patients. When indexing EOA by calculating the ratio of EOA to patient aortic annulus area to adjust for variables such as patient anatomy and valve dimensions, there was no significant difference between the two bioprostheses. CONCLUSION: Comparisons of absolute EOA values grouped by the manufacturers' valve sizes are misleading because of specific differences in geometric dimensions. The EOA:patient aortic annulus area ratio provides a new hemodynamic index which may facilitate objective comparisons between different valve types.
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Misfit and functional loading of craniofacial implants.
PURPOSE: This study sought to develop an understanding of the magnitude and types of loads generated on craniofacial implants supporting an auricular prosthesis. MATERIALS AND METHODS: Strain gauges were used to measure the in vitro and in vivo misfit loads generated when connecting auricular-style superstructures to implants and the in vivo functional load generated during the removal and insertion of the auricular prostheses. In addition, the vertical misfit of the 11 custom-built two-implant superstructures used in the in vitro study was measured. RESULTS: Superstructures used in the in vitro study that were considered clinically passive still had considerable preloads. In addition, the calibrated loads, which would result from the vertical misfit alone, did not account for the magnitude of the generated preloads. CONCLUSION: The clinical definition of misfit based on vertical distortion of the superstructure did not quantify the resulting misfit load. Measured in vivo functional loads were smaller than the misfit loads.
Adult↗
The next step in vision correction.
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Humans↗
[The progress of algorithms applied in digital hearing aid].
The paper introduced the structure of digital hearing aid in brief firstly, then analyzed and compared signal processing algorithms applied in digital hearing aid, serving respectively in multi-channel frequency compensation, noise reduction and acoustic feedback cancellation. Finally, several special signal processing techniques used in digital hearing aid were introduced.
Algorithms↗
A virtual fluoroscopy system and its use for image guidance in unicompartmental knee surgery.
The C-arm fluoroscope is an indispensable intraoperative 2D imaging device for orthopaedic surgery. However, its frequent use in an operation presents a significant radiation hazard to the theatre staff and patient. A recent technique known as virtual fluoroscopy (VF) enhances the fluoroscope's capability for image guided surgery by tracking optically the position of the C-arm, surgical instruments and the patient. Virtuality is achieved by overlay of surgical instruments onto one or more previously captured fluoroscopic images. A key benefit of VF is that it reduces considerably the radiation hazard. This paper reports on a new VF technique for tracking and calibration of the fluoroscopic C-arm. Also reported is the use of our VF system to provide a new image guided technique for the accurate placement of the femoral component of unicompartmental knee prosthesis.
Arthroplasty, Replacement, Knee↗