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At least 1,297 records · Page 72Linked to original sources
PubMed2006

The real impact of randomized clinical trials in heart valve surgery.

PURPOSE OF REVIEW: The aim of this article is to evaluate the findings of clinical trials in cardiac valve surgery and to determine the real impact in standard of care. Also, publications on randomized clinical trials were reviewed as to integrity and validity. Nineteen randomized clinical trials were identified in 11 areas of operative and clinical management. RECENT DEVELOPMENTS: The Veterans Affairs and Edinburgh Heart Valve Trials confirmed the guidelines for indications for bioprostheses and mechanical prostheses. Even current prostheses have advanced technologies but the same valve-related complications determine indications. Randomized clinical trials of mechanical prostheses failed to determine prosthesis superiority. Bioprostheses of specific manufacturers contribute sub-optimal hemodynamics in small sizes. Two trials showed lack of superiority between aortic stented and stentless bioprostheses. Autografts, not allografts, are indicated for children because of structural valve deterioration of allografts. Atrial ablation surgery with concomitant mitral valve reconstruction/replacement is safe and efficacious with at least two energy sources. Minimally invasive aortic valve replacement does not provide superior results to conventional surgery. Patient-managed anticoagulation provides the most favourable thromboembolic and hemorrhagic rates with mechanical prostheses. Prosthesis sewing cuff impregnation with a bactericidal agent to reduce the incidence of prosthetic valve endocarditis was stopped because of increased incidence of major paravalvular leak requiring reoperation. SUMMARY: Randomized clinical trials, although limited in number, have provided advancement of the standard of care. Randomized clinical trials are indicated in the management of mild to moderate ischemic mitral regurgitation and evaluation of new transcatheter technologies to conventional surgery.

Anticoagulants↗
PubMed2002

Initial selection of soft contact lenses based on corneal characteristics.

PURPOSE: To determine apical radius, surface asphericity, and horizontal visible iris diameters (HVID) in normal subjects and to find out which has the greatest influence on the corneal sagittal depth. METHODS: Videokeratoscopic data were analyzed to determine the apical radius and the p-value of the near horizontal principal meridian for 73 right and 77 left eyes. The HVID also were measured. RESULTS: Scatterplots of sagittal depth versus apical radius, p-value, and HVID indicated the strongest association between the sagittal depth and the HVID. CONCLUSIONS: Normal variations in corneal asphericity have the least influence whereas normal variations in HVID have the greatest influence in changing the corneal sagittal depth. The most appropriate measurement to take to select the optimum soft contact lens specification may be the HVID.

Adult↗
PubMed2003

Self-evaluation of contact lens wearing and care by college students and health care workers.

PURPOSE: To identify perceptions related to the wear and care and of contact lenses and self-evaluation of the knowledge regarding their cleaning and disinfection. METHODS: A survey was conducted by interviewing contact lens wearers among health care workers at a university hospital. RESULTS: Two hundred one contact lens wearers were interviewed. The average age was 23.5 years; 69.2% were female and 71.1% were college students. Approximately 55% did not consider themselves good wearers and declared as the main reason the inadequate maintenance of the contact lenses and their cases. Regarding contact lens care, 79.1% of respondents admitted not performing it correctly. CONCLUSION: Although the interviewees were health care workers, their self-evaluation regarding contact lens care showed unsatisfactory knowledge and practices related to the use and care of contact lenses.

Adolescent↗
PubMed2003

Effects of contact lenses on corneal thickness and corneal curvature during usage.

PURPOSE: To investigate the effects of contact lenses on corneal thickness and curvature. METHODS: Eighty-four eyes of 45 patients (26 female and 19 male) wearing contact lens for the first time with a median age of 23.04 +/- 7.2 years (range, 15-44 years) were included in the study. After all patients had undergone a routine ophthalmic examination, corneal thickness measurements in nine regions and corneal topography were performed before wearing contact lenses and after 1 month, 6 months, and 12 months. Patients were classified into three groups according to duration of wear. Groups were also classified into two subgroups according to the lens type (rigid gas-permeable and soft contact lenses). RESULTS: Mean visual acuity was 0.82 +/- 0.26 with spectacles and 0.92 +/- 0.26 with contact lenses. At the end of 1 month, statistically significant corneal thinning and thickening were noted in different regions in group 1. In group 2, statistically significant corneal thinning was noted in all regions with soft contact lenses and rigid gas-permeable contact lenses except in the inferior temporal region at the end of 6 months. In group 3, corneal thinning was noted in all regions with soft contact lenses and rigid gas-permeable contact lenses. This corneal thinning was statistically significant in all regions with the soft contact lenses except in the inferior nasal region and with rigid gas-permeable contact lenses except in the central region. When corneal curvatures were examined, corneal flattening was seen in groups 1 and 2. In group 3, corneal steepening was noted. CONCLUSIONS: Soft contact lenses and rigid gas-permeable contact lenses cause corneal thickening and corneal flattening in the first months, but they cause corneal thinning and corneal steepening with time. These alterations can be evaluated as evidence that contact lenses negatively influence corneal physiology.

Adolescent↗
PubMed2005

Contact lens user statistics in Okada eye clinic.

PURPOSE: To investigate the relationships between contact lens wearers, their lens wear, and treatment to provide correct instructions for use. METHOD: A total of 55,056 consumers, who purchased contact lenses in the two institutions of Okada Eye Clinic in the 1-year period from April 1, 2002 to March 31, 2003, were analyzed with regard to age, sex, contact lens brands, treatments and lens-solution combinations purchased, and patterns of wear. RESULTS: The 2-week frequent-replacement soft contact lenses were the most popular type of contact lens, and most wearers of these lenses were those in their 20s. Saline solution was the treatment purchased most often with conventional soft contact lenses. Hard contact lens wearers tended to buy treatments of the same brand as their hard contact lenses. Hydrogen peroxide was the most purchased product with the 2-week frequent-replacement soft contact lenses and multipurpose treatment the next, especially with consumers in their 20s. There were no significant sex gaps. CONCLUSIONS: The survey was conducted on a wide age range of more than 50,000 people and can be assumed to accurately reflect the tendencies of contact lens wearers in Japan. The results clearly show the actual use of contact lenses and treatments of each age group and will be useful in instructing wearers to the correct use of their treatments.

Adolescent↗
PubMed2005

An investigation of the actual conditions of use of daily-disposable soft contact lenses and two-week disposable soft contact lenses.

PURPOSE: To investigate whether daily-disposable and 2-week disposable soft contact lenses are being used correctly. METHODS: The number of purchases made and brands selected by the 44,566 consumers who purchased daily-disposable and 2-week disposable soft contact lenses in Okada Eye Clinic institutions between April 1, 2002 and November 1, 2002 were monitored. From the 7,759 respondents to a survey conducted in the clinic between November 1, 2002 and March 31, 2003, the number of purchases made and brands selected by the 1,584 respondents, whose sales records could be traced, were analyzed in further detail. RESULTS: The total number of consumers purchasing daily-disposable soft contact lenses was 14,909, and their annual average purchase was 10.56 boxes. Most purchases were of two boxes followed by purchases of four and then six. Only 6.4% of consumers purchased 24 boxes at a time. Consumers purchasing four or fewer boxes at a time accounted for 37.8%. A total of 25,705 consumers purchased 2-week disposable soft contact lenses, with an annual average purchase of 6.37 boxes per consumer. Nineteen percent of the consumers purchased eight boxes of 2-week disposable soft contact lenses per year. Most consumers tended to purchase their contact lenses in even numbers for daily-disposable and 2-week disposable soft contact lenses. Johnson & Johnson Vision Care (Jacksonville, FL) was the most popular manufacturer. According to the survey, 86.6% of the 2-week disposable soft contact lens wearers followed instructions correctly, whereas 13.4% did not. That is, they exceeded the instructed 14 days of wear. CONCLUSIONS: Annual average purchases of daily-disposable and 2-week disposable soft contact lenses tended to be in even numbers and showed differences in their sales depending on contact lens brands. The results obtained from the survey and the actual sales records correlated.

Contact Lens Solutions↗
PubMed2006

Prevalence of ocular surface symptoms, signs, and uncomfortable hours of wear in contact lens wearers: the effect of refitting with daily-wear silicone hydrogel lenses (senofilcon a).

PURPOSE: Many soft contact lens wearers have symptoms or signs that compromise successful lens wear. This study estimated the prevalence of problems in current wearers of soft contact lenses and tested the effect of refitting patients with senofilcon A silicone hydrogel lenses (ACUVUE Oasys). METHODS: Prevalence was estimated from 1,092 current lens wearers for frequent or constant discomfort or dryness, at least 2 hours of uncomfortable wear, at least grade 2 limbal or bulbar hyperemia (0-4), or at least grade 3 corneal staining (0-15). In the second part of the study, 112 of the 564 wearers classified as problem patients were refitted with senofilcon A lenses and reassessed 2 weeks later. RESULTS: Fifty-two percent (564 of 1,092) had some qualifying criteria, with dryness reported by 23%, discomfort by 13%, and at least 2 hours of uncomfortable wear by 27%. Six percent of subjects had qualifying limbal hyperemia; 10% had bulbar hyperemia; and 12% had corneal staining. After refitting 112 problem patients, 75% had less dryness; 88% had better comfort (P<0.0001 each); and 76% had fewer uncomfortable hours of wear (P=0.004). Although the average wearing time was unchanged, comfortable wearing time increased significantly (10.4 to 11.6 hours) (P=0.004). All (35 of 35) eyes with qualifying limbal hyperemia before the refit also improved (P<0.0001), as did 80% (40 of 50) of those with bulbar hyperemia (P<0.0001) and 76% (26 of 34) of those with corneal staining (P=0.005). CONCLUSIONS: Most soft lens wearers encounter clinically significant signs or symptoms with their current contact lenses. Refitting with new-generation silicone hydrogel lenses (senofilcon A) can alleviate some of these common problems.

Adolescent↗
PubMed2005

Long-term changes in corneal endothelial morphology after discontinuation of low gas-permeable contact lens wear.

PURPOSE: Low gas-permeable contact lens wear of polymethyl methacrylate or hydroxyethyl methacrylate material is known to cause morphologic abnormalities in the corneal endothelial cell layer. These lenses were widely prescribed and successfully worn until their use was actively discouraged in the late 1980s and early 1990s. This study was designed to investigate whether discontinuation of low gas-permeable contact lens wear leads to an improvement of corneal endothelial cell morphology. METHODS: At the time of discontinuation and at least 5 years after discontinuation of low gas-permeable contact lens wear, noncontact specular photographs of the central corneal endothelium were made in 66 patients (14 male and 52 female, mean age 37.7 +/- 8.4, range 24.6-69.0). By computer analysis of endothelial photographs, parameters for polymegethism and pleomorphism were calculated, as well as cell density. RESULTS: Mean follow-up time between photographs was 6.8 years (SD 1.1). Sixty-one patients were refitted with rigid high gas-permeable contact lenses or high-water-content soft lenses, and 5 patients switched to spectacle wear. A small but significant recovery of the corneal endothelial cell morphology was found for the mean coefficient of variation of cell area, from 37.5 to 35.7 (P = 0.022), and for the coefficient of variation of the number of sides, from 13.1 to 12.4 (P = 0.004). The mean percentage of hexagonal cells increased from 54.2 to 56.2 (P = 0.013). Although the corneal endothelial cell morphology improved significantly on cessation of LGP contact lens wear, the values did not return to levels observed in normal, non-contact lens wearing individuals. During follow-up, the mean endothelial cell density decreased significantly (P = 0.001) from 2994 to 2890 (a 3.5% cell loss in 6.8 years), which is similar to the known normal age-related cell loss of 0.6% per year in non-contact lens wearing healthy individuals. CONCLUSION: Endothelial polymegethism and pleomorphism caused by PMMA or HEMA contact lens wear is partly reversible.

Adult↗
PubMed2004

Evaluation of transfer impressions for osseointegrated implants at various angulations.

The accuracy of impressions that transfer the relationship of the implant to the metal framework of the prosthesis continues to be a problem. This study was designed to evaluate the accuracy of the transfer process under variable conditions with regard to implant analog angulations, impression materials, and techniques. Replicas (n = 60) of a metal matrix (control) containing four implants at 90 degrees , 80 degrees , 75 degrees , and 65 degrees in relation to the horizontal surface were obtained by using three impression techniques: T1-indirect technique with conical copings in closed trays; T2-direct technique with square copings in open trays; and T3-square copings splinted with autopolymerizing acrylic resin; and four elastomers: "P"-polysulfide; "I"-polyether; "A"-addition silicone; and "Z"-condensation silicone. The values of the implant analog angulations were assessed by a profilometer to the nearest 0.017 degrees , then submitted to analysis of variance for comparisons at significance of 5% (P < .05). For implant analog at 90 degrees , the material "A" associated with T2 and material "Z" with T3 behaved differently (P < .05) from all groups. At 80 degrees , all materials behaved differently (P < .01) with T1. At 75 degrees , when T1 was associated, materials "P" and "A" showed similar behavior, as well as materials "I" and "Z"; however, "P" and "A" were different from "I" and "Z" (P < .01). When T3 was associated, all experimental groups behaved differently among them (P < .01). At 65 degrees , the materials "P" and "Z" behaved differently (P < .01) from the control group with T1, T2, and T3; the materials "I" and "A" behaved differently from the control group (P < .01) when T1 and T2, respectively, were associated. The more perpendicular the implant analog angulation is in relation to the horizontal surface, the more accurate the impression. The best materials were material "I" and "A" and the most satisfactory technique was technique 3.

Dental Casting Technique↗
PubMedDate not supplied

Conjunctival squamous cell carcinoma of the orbit 40 years after enucleation.

Conjunctival squamous cell carcinoma developed in a 51-year-old man 40 years after he had enucleation of his left eye because of an explosion injury. He had worn several ocular prostheses for more than 40 years. Recently he had noticed an increasing sanguineous conjunctival discharge, a foreign body sensation, and swelling of his left lower eyelid. Incisional biopsies of an underlying conjunctival mass revealed squamous cell carcinoma. His work history did not involve exposure to radiation, chemicals, or the sun. The authors concluded that squamous cell carcinoma in this case was caused by chronic irritation as the result of long-standing use of a poorly fitting ocular prosthesis.

Blast Injuries↗
PubMed2004

Safety and effectiveness of a new saline filled testicular prosthesis.

PURPOSE: Testicular prostheses have been used for 50 years to replace missing or removed testes. In 1995 the manufacture of the silicone gel filled testis prosthesis in the United States was discontinued because of concern about the safety profiles of other implants. We assessed the safety and effectiveness of a new, saline filled implant for testicular replacement. MATERIALS AND METHODS: This open label, multicenter, prospective, case controlled clinical trial was done at 18 American tertiary referral centers. Adult and pediatric male patients missing 1 or 2 testes and without evidence of active malignancy or rheumatological disease were enrolled. All patients underwent formal rheumatological and urological evaluation prior to and after prosthesis placement. Main outcome measures were prosthesis safety assessed by adverse events and effectiveness assessed by changes in testis dimension. Secondary outcome measures were quality of life assessments with 3 validated instruments. All patients were followed a minimum of 1 year in this 5-year study. RESULTS: Postoperative adverse events observed in 19% of 149 patients included device related discomfort or pain in 3%, scrotal edema in 1.3%, infection in 1.3%, extrusion in 2.6%, deflation in 0.7% and pulmonary emboli in 0.7%. No patient reported rheumatological symptoms at 1 year. Testis dimensions were significantly increased in patients missing a testis at baseline (p <0.001). Subjective assessment of testicular appearance was significantly improved (p <0.001) and scores were stable or significantly improved in 2 of 3 quality of life instruments. CONCLUSIONS: At short-term followup a new, saline filled testis prosthesis appears safe and well tolerated. Importantly validated self-esteem measures also suggest improvement in quality of life after prosthesis placement.

Adolescent↗
PubMed2005

Evaluation of the advance off-stylet insertion technique and the cochlear insertion tool in temporal bones.

OBJECTIVE: The concept and design of new cochlear implant electrodes is a challenging process. To evaluate new electrode designs, we present a study that uses a microgrinding procedure to evaluate damage to the microstructures of the cochlea resulting from the insertion procedure. In this study, we compared different insertion techniques with the Contour electrode with Softip for placement inside the cochlea and any resulting damage. METHODS: Twenty-five fresh frozen human temporal bones were used to compare electrode insertion characteristics with three insertion techniques (i.e., conventional insertion, Advance Off-Stylet performed manually, and Advance Off-Stylet performed with insertion tool) and two prototype variants of the Contour electrode with Softip (referred as Softip I and Softip II in this article). Five temporal bones were used for each arm of the study: Softip I electrode and conventional insertion; Softip I electrode and manual Advance Off-Stylet insertion; Softip I electrode and Advance Off-Stylet insertion with an early experimental insertion tool; Softip II prototype electrode and manual Advance Off-Stylet insertion; and Softip II prototype and Advance Off-Stylet insertion with a prototype insertion tool. The temporal bones were dehydrated and embedded in epoxy and used for the microgrinding procedure. Resulting images were documented and compared with conventional radiographic images. RESULTS: Our results showed that, especially when using the conventional insertion technique with Softip I electrode arrays, basilar membrane perforations were observable. Using the prototype insertion tool, good placement of the electrode array but also two basilar membrane perforations (one with each type of electrode) were observed. In contrast, the Advance Off-Stylet insertion technique did not show basilar membrane perforation with Softip I and II electrodes and resulted in reliable perimodiolar placement of the arrays. CONCLUSION: Using microgrinding of temporal bones, the Advance Off-Stylet insertion technique was proven to enable more atraumatic insertions of Contour electrodes with Softip and to provide very reliable perimodiolar placements.

Basilar Membrane↗
PubMedDate not supplied

Replacement of the left-side valves of an implanted total artificial heart.

The MagScrew total artificial heart (TAH) is under development. Despite its anticipated durability and reliability, the possibility of a bioprosthetic valve malfunction exists. As a result, the potential for valve replacement surgery, instead of device replacement, would be desirable after a TAH implant. In two of our 90-day animal experiments, we successfully replaced the left-side valves through a left thoracotomy opposite to the right-sided incision site for the initial TAH implant. The results of these cases suggest that the left-side valves could also be replaced through a left thoracotomy approach in humans. To confirm the ability to access the left-side valves in humans, four human cadaver studies were performed with the use of a mock pump designed for human application. This report describes the operative techniques for left-side valve replacement in animals and discusses the advantages of a left thoracotomy in clinical situations, based on results from the human cadaver studies.

Animals↗
PubMed2005

A model for cochlear implant electrode insertion and force evaluation: results with a new electrode design and insertion technique.

OBJECTIVES AND HYPOTHESIS: This study has the specific aim of evaluating the insertion characteristics of a new cochlear implant electrode. Techniques for evaluation of fluoroscopic real time mechanical insertion dynamics, histologic electrode position and trauma results, hydraulic force, and mechanical insertion forces are presented. In addition, this study should serve to present a novel model for cochlear implant electrode insertion evaluations. STUDY DESIGN: Prospective analysis using a series of analytical techniques. METHODS: All studies are conducted in fixed cadaveric temporal bones. Real time fluoroscopic insertion evaluations, histologic evaluations for trauma and electrode position in embedded bones, hydraulic measures, and mechanical intracochlear force measurements are conducted with a current and new electrode. RESULTS: The Contour Advance electrode provides a more reliable and less traumatic insertion when deployed with the Advance Off Stylet technique. This is largely because of a reduction in intracochlear outer wall force generation. Fluoroscopic and histologic analysis reveal a smooth insertion without reliance on cochlear outer wall contact. No hydraulic forces were detected when measured from the superior semicircular canal ampulla. CONCLUSION: The model used for this study provides valuable information to cochlear implant surgeons and design engineers. The Contour Advance electrode, inserted with the Advance Off Stylet technique, represents an improvement over the Contour electrode inserted with the standard insertion technique.

Cadaver↗
PubMed2005

Cochlear implantation in deaf infants.

OBJECTIVES: With the application of universal newborn hearing screening programs, a large pool of newly identified deaf infants has been identified. The benefits of early intervention with cochlear implants (CI) is being explored. Mounting evidence suggests that age at implantation is a strong predictor of language outcomes. However, new behavioral procedures are needed to measure speech and language skills during infancy. Also, procedures are needed to analyze the speech input to young CI recipients. STUDY DESIGN: Cohort-sequential. METHODS: Thirteen infants with profound hearing loss who were implanted between the ages of 6 to 12 months of age participated in this study. Eight participated in two new behavioral methodologies: 1) the visual habituation procedure to assess their discrimination of speech sounds; 2) the preferential looking paradigm to assess their ability to learn associations between speech sounds and objects. Older implanted infants and normal-hearing infants were also tested for comparison. The pitch of mothers' speech to infants was analyzed. RESULTS: Patterns of looking times for the very early implanted infants were similar to those of normal hearing infants. Mothers' speech to infants with CIs was similar in pitch to normal-hearing infants who had the same duration of experience with sounds. CONCLUSIONS: No surgical or anesthetic complications occurred in this group of infants, and the pattern of listening skill development mirrors that seen in normal-hearing infants. Mothers adjust their speech to suit the listening experience of their infants.

Audiometry↗
PubMed2006

In vitro model for intraoperative adjustments in an implantable hearing aid (MET).

OBJECTIVE: Assessment of the optimal static preloading of Otologics Middle Ear Transducer (MET) Ossicular Stimulator, when coupled to the incus. BACKGROUND: The MET Ossicular Stimulator is a partially implantable electromagnetic middle ear hearing device that transmits vibrations to the ossicular chain. The vibration patterns were measured with laser-Doppler vibrometry. STUDY DESIGN: Experimental. MATERIAL: We used three human cadaveric temporal bones (TB) and one MET ossicular stimulator. METHODS: Laser-Doppler vibrometry was used for the selection of TBs. The cochlea was subsequently extirpated from the posterior side to measure the vibrational patterns (VP) of the footplate. Three TBs with different VP were selected based on data obtained from volunteers with normal hearing (n = 110): one TB with a VP larger than +1 SD, one TB with a VP in the range of +/-1 SD, and 1 TB with a VP smaller than -1 SD. Transfer functions were calculated between VP of the measurement points at the coupling rod, umbo, incus, and footplate. The TBs were subsequently defrosted. The MET was implanted and coupled to the ossicular chain. Different coupling loads were measured at the incus, the umbo, and the footplate. RESULTS: Optimal transfer function between the MET transducer and the oval window was achieved during contact when the coupling rod advanced 0.0625 mm (90 degrees rotation). Additional advances of 0.0625 mm (180 degrees turn = 0.125 mm) resulted in a decreased vibrational amplitude, ranging between 20 and 40 dB below 3 kHz. The lowest linear distortion occurred up to 10 kHz during direct contact without advancing the coupling rod.

Acoustic Impedance Tests↗