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At least 1,261 records · Page 70Linked to original sources
PubMed2003

Tympano-ossiculoplasty utilizing the Spiggle and Theis titanium total ossicular replacement prosthesis.

OBJECTIVE: Since 1993, titanium prostheses have been used in Europe as a biocompatible implant for ossicular reconstruction. More recently, the titanium ossicular prosthesis has become more widely available in the United States as a newer means of surgical restoration of hearing. We will review the hearing results of patients who have undergone tympano-ossiculoplasty using a titanium total ossicular replacement prosthesis (TOP). We will compare these results to our previously published results using the porous polyethylene TOP. METHODS: Retrospective review in a tertiary otologic practice. RESULTS: Eighteen patients underwent tympano-ossiculoplasty with a titanium TOP. Among these patients, 10 cases involved revision of a previously placed ossicular prosthesis. Hearing results showed that 16 of 18 patients (89%) had closure of the postoperative air-bone gap to within 20 dB, and the average air-bone gap improvement was 23 dB. The average follow-up time was 8 months (range, 2-21 months). The results of this initial evaluation compare favorably with the results that we obtained using a porous polyethylene TOP in which 67% of 133 patients closed the air-bone gap to within 20 dB. CONCLUSION: We have recently begun using the titanium TOP, which has resulted in improved postoperative hearing when compared with the porous polyethylene TOP. In the future, longer follow-up and increased patient numbers will strengthen our conclusions.

Adolescent↗
PubMed2004

Results with titanium ossicular reconstruction prostheses.

OBJECTIVES/HYPOTHESIS: Despite the enthusiasm of recent short-term reviews, no center in the United States has published results meeting American Academy of Otolaryngology-Head and Neck Surgery guidelines with titanium-based prostheses. The purpose of the study was threefold. The first purpose was to review results with a titanium prosthesis system in cases meeting American Academy of Otolaryngology-Head and Neck Surgery reporting guidelines. The second was to compare these results with previously published results using non-titanium-based prostheses. The third was to examine the authors' results for any evidence of a "learning curve." STUDY DESIGN: Retrospective chart review was performed for the period from February 2000 to August 2001 and for the period from July 2002 to February 2003. METHODS: Of 313 cases, 130 consecutive cases were identified in the first period and 65 in the second time period. One hundred two patients had adequate follow-up for published guidelines. All cases were performed by the senior author (c.g.j.). Comparison data were obtained from a previous publication involving the senior author. RESULTS: Successful rehabilitation (<or=20 dB pure-tone average air-bone gap) of conductive hearing loss was obtained in 70% of partial ossicular chain reconstructions and 44% of total ossicular chain reconstructions when titanium prostheses were used. Comparison data revealed successful rehabilitation in 48% and 21% of non-titanium-based partial and total reconstructions, respectively. Postoperative pure-tone average air-bone gaps were not significantly different when compared with results in the period from July 2002 to February 2003. CONCLUSION: Newer titanium-based ossicular reconstruction devices represent an improvement over previously used non-titanium-based prostheses. The authors think that this improvement is realized rapidly because no learning curve existed in their data.

Bone Conduction↗
PubMed1994

Blink-induced variations in visual performance with toric soft contact lenses.

BACKGROUND: Blink-induced lens movement causes a reduction in visual performance that is potentially greater with toric than with spherical soft contact lenses because of the combination of vertical lens movement and rotation. This study examined the effect of the two most common methods of toric lens stabilization (prism ballast and dynamic stabilization) on vision. METHOD: Four toric soft contact lens wearers were the subjects (astigmatic range 1.25 to 2.25 D). Stimulus presentation (10.5 cpd sine wave grafting flashed for 16 ms) occurred at specified times up to 400 ms after the blink. Contrast thresholds were determined monocularly with spectacles and the two types of contact lenses. RESULTS: For the grouped data, the prism balasted lens gave better overall visual performance than the dynamic stabilization at all times after the blink. Separate analysis of subject data suggested that this general pattern was not true for all individuals. CONCLUSIONS: Clinical evaluation of different lens designs on individual patients is required for achieving the optimum visual performance with toric soft lenses.

Blinking↗
PubMed1997

Potential sources of bacteria that are isolated from contact lenses during wear.

PURPOSE: The aim of this paper was to determine the possible contamination sources of contact lenses during wear. METHODS: Potential sources of the microbiota that colonized hydrogel contact lenses during wear were examined. The microorganisms that colonize contact lenses were grown, identified, and compared to those microorganisms that colonized the lower lid margins, upper bulbar conjunctiva, hands, and contact lens cases of contact lens wearers. In addition, the incidence of contamination of the domestic water supply in the Sydney area was obtained, and this was compared to the incidence of colonization of contact lenses by microorganisms in general and gram-negative bacteria in particular. RESULTS: There was a wide diversity of bacteria that were isolated from each site sampled. Coagulase-negative staphylococci and Propionibacterium spp. were the most common isolates from all ocular sites examined, and constituted the normal ocular microbiota. Other bacteria, including members of the families Enterobacteriaceae and Pseudomonadaceae, were isolated infrequently from all sites, but most frequently from contact lens cases. Statistical analysis revealed that there was a correlation between the isolation of bacteria from the contact lens and the lower lid margin (p < 0.001). Analysis of this correlation revealed that this was true for the normal microbiota. A correlation was also noted between the colonization of contact lenses by gram-negative bacteria and contamination of the domestic water supply. DISCUSSION: This study has demonstrated that the likely route for the normal ocular microbiota colonizing contact lenses is via the lid margins, whereas colonization by gram-negative bacteria, including potential agents of microbial keratitis, is likely to be from the domestic water supply.

Bacteria↗
PubMed1998

Validating a "pillar and collar" technique for measuring the edge lift of rigid contact lenses.

PURPOSE: The clinical importance of the edge lift of rigid contact lenses is often neglected, possibly due to previous difficulties in its measurement. A new method of measuring axial edge lift (AEL) and radial edge lift (REL) using standard contact lens verification equipment, such as an optical spherometer, a thickness gauge, and contact lens V gauge, is described. METHODS: The technique was validated for trueness (accuracy) and precision (repeatability) by measuring the edge lift of a number of monocurve lenses, manufactured both with and without a normal edge finish. RESULTS: Edge lift was measured to an accuracy of 0.01 mm. CONCLUSIONS: As long as a mean of eight independent measurements of back optic zone radius (BOZR), sagitta, and one measurement of center thickness are taken, the pillar and collar technique is capable of producing accurate and repeatable measurements of the edge lift of a rigid contact lens.

Contact Lenses↗
PubMed1998

"Pillar and collar" technique for measuring the axial edge lift of multicurve rigid lenses.

BACKGROUND: The method of using an optical spherometer and a lens thickness gauge, in combination with a pillar and collar, has previously been shown to be repeatable and accurate (to 0.01 mm) in measuring the edge lift of rigid monocurve lenses. PURPOSE: This paper goes on to validate the technique for measurements taken on edge-finished multicurve rigid lenses. METHODS: The axial edge lift (AEL) of a series of multicurve rigid lenses having known values of AEL was measured using an optical spherometer, a thickness gauge, and contact lens V gauge in a similar way as was described in the companion paper. RESULTS: The results show that as long as a correction factor of 0.01 mm is applied, as found in the previous paper, the technique will allow satisfactory verification of the edge lift. CONCLUSIONS: The technique is accurate and reproducible, even in multicurve lens designs, provided that a calibrating correction factor of 0.01 mm is applied to account for methodological error. It will also indirectly allow the accuracy of manufacture of the peripheral curves and diameters of any rigid contact lens to be verified.

Contact Lenses↗
PubMed1998

Comparison by contact lens cytology and clinical tests of three contact lens types.

PURPOSE: To determine if hydrogel lens materials from different FDA groups have different effects on the human ocular surface. METHODS: Contact lenses from Groups I and II, and Group IV were tested on 10 healthy adapted hydrogel contact lens wearers. For each comparison, the subject wore 2 new contact lenses for approximately 45 min. Lens movement was measured, and comfort evaluated using a subjective scale. After removal of the lenses, fluorescein staining and tear break-up time were measured. Cells were collected by contact lens cytology (CLC), and the size and number of cells harvested from each lens were determined. RESULTS: There were differences between lens groups in lens movement and comfort, but no differences in fluorescein staining or tear break-up time. CLC showed no differences in cell counts or cell size. There was no correlation between the results of CLC and the clinical tests for lens movement, lens comfort, tear break-up time, and fluorescein staining. CONCLUSIONS: With short durations of lens wear, differences in ionicity and water content have no effect upon the size and number of cells collected from a contact lens. This suggests that, in the short-term, the shedding of cells beneath a hydrogel lens is not affected by the choices of lens material.

Adult↗
PubMed2003

Recurrent lens binding and central island formations in a fast-responding orthokeratology lens wearer.

A 12-year-old girl with a history of fast myopia progression underwent advanced orthokeratology (ortho-k) treatment and suffered from recurrent lens binding and central corneal staining. The problem could not be fixed by lens fenestration and refitting with a less aggressive lens (three-zone ortho-k) design. After refitting with a lower target advanced ortho-k lens, these complications were no longer occurring, and the amount of power reduction was greater than expected considering the target designed for the refitted lenses. During the following 15 months of ortho-k lens wear, there was no clinically significant change to her refractive error. The patient and her parents were happy with the outcome, although the refractive error was not totally eliminated and she still needed to wear spectacles for clear vision. Possible etiologies of the complications are discussed.

Child↗
PubMed2003

Comparison of reverse-geometry lens designs for overnight orthokeratology.

PURPOSE: The efficacy of overnight wear of four types of reverse-geometry lenses was compared. The length of time needed to achieve correction and any adverse events that occurred during the course of the study were recorded. METHODS: In this prospective, randomized study, 60 subjects (18 to 35 years old) with refractive error between -1.00 to -4.00 D (cyl </= -1.50) wore reverse-geometry lenses overnight only. All subjects were assigned a Rinehart Reeves lens in one eye, and subsets of 20 subjects were randomly assigned a Mountford BE, DreimLens, or Contex D Series 4 lens for the contralateral eye. Visits included baseline, dispensing, 1 day, 1 week, and 1 month. Biomicroscopy, unaided visual acuity, subjective refraction, best-corrected visual acuity at high and low contrast and high and low illumination, corneal topography, and subjective rating data were collected. RESULTS: Forty-six subjects completed the study. At 1 month, there were no significant differences between lens types in their effect on unaided visual acuity, subjective sphere, subjective cylinder, best-corrected visual acuity at high and low contrast at high illumination and low contrast at low illumination, apical corneal radius, corneal eccentricity, and subjective ratings. Between 1 week and 1 month, there was a significant improvement in subjective ratings of quality of day and night vision (p < 0.05) but no significant change in the objective measures. No significant ocular adverse events were observed during the trial. CONCLUSIONS: The lens types tested were all similarly effective in the reduction of myopic refractive error. Subjective ratings continued to improve after objective measures stabilized at 1 week. Overnight lens wear proceeded for 1 month without significant adverse reactions.

Adult↗
PubMed1981

Lacrimal gland adenoid cystic carcinoma: intracranial and extracranial en bloc resection.

Adenoid cystic carcinoma of the lacrimal gland is a rare tumor, although it is the malignancy most frequently arising in the gland. Treatment has been unsuccessful generally, with a 15-year survival of less than 20 percent. Our experience with this tumor in a 61-year-old woman has led to a proposal for therapeutic management based on awareness of the lesion's natural history, an understanding of regional anatomy, and familiarity with therapies reported in the literature. The feasibility of adequate tumor ablation is determined from preoperative evaluation, including CT scan, initial exploratory craniotomy, and frozen-section examination of the cranial nerves transversing the orbit. Once resectability is confirmed, "curative" intracranial and extracranial en bloc resection is performed, including the tumor, the lacrimal gland, and all contiguous structures. The defect is immediately resurfaced with and "ice cream cone" forehead flap in anticipation of adjuvant radiotherapy. An orbital prosthesis is fitted as soon as the radiation reaction subsides, and a postablative CT scan is obtained as the baseline for follow-up. It remains to be seen whether this application of the technology of CT scanning and the techniques of craniofacial surgery will improve the prognosis for adenoid cystic carcinoma arising in the lacrimal gland.

Carcinoma, Adenoid Cystic↗
PubMed1989

Use of contoured and stabilized conchal cartilage grafts for lower eyelid support: a preliminary report.

Lower lid stability can be affected by many conditions involving the lid directly, e.g. facial palsy, facial clefts, trauma, or tumors. Secondary stretching due to a poorly fitting orbital prosthesis can have the same effect. In 41 such eyelids, stability was obtained by inserting a large cartilage graft sutured to the tarsal plate and the infraorbital rim. Thirteen patients had tarsoconjunctival wedge resections, and 10 had lateral canthopexies performed at the same procedure. One graft was too small and was later replaced. There was one hematoma, which was evacuated. There were no other lid or visual problems. The follow-up is short, 21 months maximum, but so far the results are very satisfactory.

Cartilage↗
PubMed1998

Determinations of strength of synthetic hydroxyapatite ceramic implants.

To study the physical strengths of various types of synthetic high porosity hydroxyapatite plates, we constructed samples of a fixed shape, 8 X 25 mm in size, with varying degrees of thickness (3 to 10 mm) and porosity (40, 50, and 60 percent), as well as samples with varying degrees of curvature and samples constructed with computer-aided design-computer-aided manufacturing (CAD-CAM) technology based on a real-size model made with laser lithography from computed tomography data. The strength of the samples was studied with the three-point bending test and crush tests. Studies showed that strength decreases with increasing porosity and increases with increasing thickness. In addition, results of testing plates of varying shapes and degrees of curvature revealed that the effects of these variations were small and that when the width and thickness were held constant, changing the curvature of the entire unit (from a height of 20 to 30 mm) or altering both sides had no remarkable effect on strength. On the other hand, strength testing of plates of various shapes and thicknesses constructed from clinical computed tomography data revealed that minimum optimization of the parameters was achieved when plates had a porosity of about 40 percent and a thickness of about 8 mm.

Biomechanical Phenomena↗
PubMed1998

An innovative method of reconstruction of large skeletal chest wall defects.

The reconstruction of large skeletal defects of the chest wall is considered complex and difficult. A simple technique for this repair, using polymethylmethacrylate ribs that are prefabricated in a prosthodontic laboratory using heat cure polymer, is presented. These ribs are used as bone substitutes while reconstructing the chest wall defect. The prefabricated polymethylmethacrylate ribs have been used to reconstruct the large chest wall defects after resection of chest wall tumors in three patients. There was risk of severe paradoxical movement of the chest wall without the skeletal defect reconstruction. In all of the cases, there was no need for postoperative mechanical ventilation and there was no paradoxical movement. Cosmetically, it was highly satisfactory. In one patient, the stainless steel wire caused a sinus after 1 year of reconstruction, requiring removal of the wire and the rib, but it did not compromise the stability of the chest wall. We conclude that reconstruction of large chest wall defects with prefabricated polymethylmethacrylate ribs is simple, cost-effective, and easy to plan and execute.

Adult↗
PubMed1997

The abutment seating jig: a prosthodontic implant adjunct.

Rapid, accurate seating of screw-retained implant abutment heads, where timing is controlled by internal or external hex designs, can be readily accomplished with individual, custom-cast abutment head location devices. The devices are especially useful when the abutment head-implant body complex is to be permanently cemented. The use and design of abutment seating jigs for single tooth implants and completely implant or implant and natural tooth-supported prostheses are described.

Dental Abutments↗
PubMed2003

Update on bilateral cochlear implantation.

PURPOSE OF REVIEW: Providing a unilateral cochlear implant in a patient with a profound bilateral hearing loss has now been a standard clinical practice for more than a decade. Although results are often very good, normal hearing has not been restored. One exciting opportunity to improve hearing in this population is to provide a second implant. However, it is not obvious that bilateral electrical stimulation can be integrated by the central nervous system. This article describes binaural hearing and reviews currently published articles on binaural cochlear implants. RECENT FINDINGS: Controlled laboratory trials have focused on distinguishing different categories of potential binaural advantages. A potential summation effect occurs when the same stimulus is available at two ears. Listening in noise with two ears should be better than listening with one ear when the additional ear is away from the noise. This head shadow benefit results from acoustic effects, not physiologic ones. When the second ear is added near the noise source, a binaural squelch benefit can occur, requiring neural integration from both sides. Finally, two ears may improve sound localization. Binaural implantees generally benefit from head shadow effects. Only some benefit from summation and squelch effects. Most, but not all, show improved horizontal plane localization. SUMMARY: It is now appropriate to begin experimental studies of binaural cochlear implants. Preliminary results show promise to improve head shadow, a physical advantage, and sound localization. Some benefits have been observed for improved summation and squelch. These findings have demonstrated that the brain can integrate electrical stimulation from the two ears. Future studies will be required to maximize this binaural hearing.

Cochlear Implantation↗
PubMed2000

Enucleation, evisceration, and sympathetic ophthalmia.

This year's review of enucleation, evisceration, and sympathetic ophthalmia yielded a multitude of studies and data. Articles ranged from single case reports to large clinical series and in-depth subject overviews. With regard to enucleation, several new HA implant variations were described, along with limited clinical experience. Various techniques for management of postenucleation and evisceration complications also were described, including management of infection, implant exposure, and postenucleation socket syndrome. The risk of sympathetic ophthalmia after evisceration, as compared with enucleation, remains a highly polarized and inconclusive subject.

Eye Enucleation↗
PubMed2001

Lens implant selection with absence of capsular support.

If contact lens or spectacle correction is not viable, little debate exists that the secondary placement of an intra-ocular lens (IOL) is the method of choice in the absence of capsular support. The choice of IOL mainly depends on the preoperative status of the eye (eg, aphakia in children) and the selected location for the implant. Theoretically, there are several IOL implantation approaches in cases without capsular support: an angle-supported anterior chamber (AC) IOL, an iris-fixated ACIOL, an iris-sutured or iris-fixated posterior chamber (PC) IOL and a transsclerally sutured PCIOL. No consensus exists, however, on the indications as well as on the relative safety and efficacy of these different options. Implantation of modern ACIOLs, like the refined open-loop or iris-fixated claw (toric) ACIOLs, have regained popularity and provide a valuable alternative to sutured PCIOLs. However, in the absence of capsular support, the transsclerally sutured PCIOLs offer numerous advantages for certain eyes. Because of its anatomic location, the sutured PCIOL is more appropriate for eyes with compromised cornea, peripheral anterior synechiae, shallow anterior chamber, or glaucoma. Moreover, sutured PCIOLs are appropriate if the patient with aphakia is young or has a life expectancy of 10 years or more. Recent technological advances, including PCIOL with iris diaphragm for aniridia, toric ACIOLs, and small-incision surgery with foldable, transsclerally sutured IOLs, seem to further improve clinical outcomes.

Anterior Eye Segment↗