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Biomedical subjects

J Shea

Publications and source records attributed to J Shea.

At least 19 recordsLinked to original sources
PubMed1997

Effect of cementless acetabular cup geometry on strain distribution and press-fit stability.

Use of cementless acetabular cups, which are slightly larger than the reamed acetabulum, can provide press-fit stability without screws; however, the ideal cup geometry to maximize stability is not clear. Acetabular strain distribution, deformation, and implant stability were studied using an axisymmetric finite-element model, and mechanical stability was assessed by testing lever-out and extraction forces required to displace different cup geometries from foam bones. The implants tested included four nonhemispheric cup geometries and 1- and 2-mm oversized hemispheric geometries. A nonhemispheric cup that provides a gradual transition from a hemisphere at the dome to a larger peripheral dimension appears to maximize peripheral strains and implant stability without increasing overall acetabular deformation as much as a larger oversized hemispheric cup.

Acetabulum↗
PubMed1997

How preliminary data affect people's stated willingness to enter a hypothetical randomized controlled trial.

PURPOSE: To explore how preliminary trial data affect the general public's stated willingness to enter a randomized clinical trial. METHODS: We asked 165 prospective jurors to imagine that their physicians wanted them to enroll in a clinical trial. We then presented them with scenarios portraying preliminary trial results--for example, 9 out of 10 patients get better with drug A and 5 out of 10 get better with drug B--and asked after each scenario, whether they would choose to be part of the trial. We designed the scenarios to test how stated willingness to enter the trial would be influenced by: 1) the difference in effectiveness of the 2 treatments based on the patients enrolled thus far; and 2) by the chance that the difference in effectiveness was random (i.e., the P value). The subjects' willingness to enter the trial at various decision points was analyzed using logistic regression. RESULTS: Fewer subjects were willing to enter the trial as preliminary data indicated either an increasing difference in the effectiveness of the two treatments or an increasing statistical significance of that difference. For example 75% of subjects were willing to enter the research trial before any preliminary data were presented, but this number fell to 49% when subjects were presented with preliminary data showing that 9 out of 10 patients improved with one treatment and 5 out of 10 with the other. Multivariable logistic regression revealed that higher P values (odds ratio = 4.29; P < 0.001; 95% CI: 2.22-8.28) and smaller differences in effectiveness (odds ratio = 0.02; P < 0.001; 95% CI: 0.00-0.07) implicit in preliminary data presented to subjects made subjects less likely to agree to enter clinical trials. After adjustment for other relevant variables, male gender was associated with increased willingness to enter the trial. CONCLUSION: A subjects' willingness to enter the hypothetical trial was influenced by preliminary data. Fewer subjects were willing to enter the trial as the differences in benefit between 2 treatment groups increased. However, the majority of subjects were willing to enter the hypothetical trial even when preliminary evidence strongly favored one treatment over another. Given the importance of informed consent in entering patients in clinical trials, these results should be confirmed in actual trial settings.

Adult↗
PubMed1996

A prospective randomized study comparing short- and intermediate-term perioperative outcome variables after spinal or general anesthesia for lumbar disk and laminectomy surgery.

General or regional anesthesia may be used for lumbar laminectomy. To determine whether one method is superior, 122 patients were randomly assigned to receive either a standard general anesthetic (GA) or spinal anesthesia (SA) supplemented with intravenous (IV) propofol sedation. Data from the intraoperative period through hospital discharge were collected and compared. Demographically, both groups were similar. Total anesthesia (131.0 +/- 4.3 vs 106.6 +/- 3.2 min) and surgical times (81.5 +/- 3.6 vs 67.1 +/- 2.8 min) were longer in the GA group. Intraoperative hemodynamics were similar between groups except that the incidence of increased blood pressure was more frequent with GA (26.2% vs 3.3%). Blood loss was less during SA (133 +/- 18 mL vs 221 +/- 32 mL). Postanesthesia care unit (PACU) heart rates and mean arterial pressures were higher in the GA group. Peak pain scores in the PACU were higher after GA compared with SA (58 +/- 4 vs 22 +/- 3) as were the number of patients who required analgesics. Severe nausea was more common in the GA group both in the PACU and during the 24 h after surgery. Analgesic requirements after discharge from the PACU, urinary retention, and days in the hospital did not differ between groups. This study suggests that SA may be superior to GA both intraoperatively and postoperatively for lumbar spine procedures lasting less than 2 h.

Adult↗
PubMed1996

SF-20 score and item distributions in a human immunodeficiency virus-seropositive sample.

The question of whether the full range of possible health states is measured by the Medical Outcomes Study (MOS) 20-Item Short-Form Health Survey (SF-20) in human immunodeficiency virus (HIV)-seropositive individuals is examined in this article. Ninety-five HIV-seropositive men (37 with asymptomatic infection, 58 with symptomatic infection) from two primary care practices were enrolled. Patients completed the SF-20 evaluating six dimensions of health status. Asymptomatic patients reveal substantial skew in score distributions for the dimensions of physical (-1.60), role (-1.19), and social (-1.13) functioning; no substantial skew is exhibited by symptomatic patients. Both subgroups reveal ceiling effects for physical, role, and social functioning, and pain dimensions; asymptomatic patients' ceiling effects are higher (physical functioning: 65% versus 31%; role functioning: 73% versus 41%; social functioning: 54% versus 43%; and pain: 41% versus 24%). Patients from both subgroups reveal floor effects for the role functioning dimension (asymptomatic patients, 22%; symptomatic patients, 34%). When looking at items rather than scales, asymptomatic patients' item distributions for the physical, role, and social functioning, and pain dimensions reveal clustering toward positive health states in most items; distributions of symptomatic patients are similar. Because this HIV-seropositive sample exhibits substantial ceiling effects in four of six SF-20 dimensions, effects that particularly are notable for asymptomatic patients, these dimensions should be revised for use in HIV-seropositive individuals or a disease-specific quality of life instrument should be constructed.

Activities of Daily Living↗
PubMed1996

Endoscopic closure of postsurgical anterior cranial fossa cerebrospinal fluid leaks.

OBJECTIVE: The primary objective of this study is to present an alternative technique to closure of anterior cranial fossa cerebrospinal fluid (CSF) leaks. This study also serves to review our experience with our technique and presents some technical "tricks" we have learned through experience. METHODS: The design of this study is a clinical chart review. The setting is an academic medical center. RESULTS: Eight patients were referred for closure of postsurgical CSF leaks. Seven of eight patients underwent closure with one attempt and closure was achieved after a second attempt in one patient. Follow-up ranged from 1.5 to 4.0 years. There were no complications. No patient developed an acute or delayed episode of meningitis. CONCLUSION: The technique of endoscopic closure of a CSF leak is a safe and effective means for closure of a postsurgical anterior cranial fossa CSF fistula when performed by an experienced operator.

Adenoma↗
PubMed1993

The effects of high and low BACs on the Hoffmann reflex.

The purpose of this study was to measure and assess the magnitude and latency of the H-reflex and M-response between pre- and post-alcohol consumption. Also of interest was the comparison of the H-reflex and M-response between the rising and falling curves of BAC. Seven male volunteer subjects participated in this study. Testing started with pre-alcohol BAC and EMG recordings from the tibial nerve following an electrical stimulation. After alcohol consumption, BAC readings were obtained every five minutes, and the EMGs were recorded at the following BAC levels (in mg/dl): 75, 100, and falling 75. H-latency, H-amplitude, and M-response were identified within the EMG signals. The analysis focused on the comparisons of these measures between each of the BAC levels and the baseline, as well as between the rising and falling BACs. Results showed that, overall, the H-reflex and M-response were depressed following alcohol consumption. In addition, the depression of H-reflex appeared to be greater during the rising curve than the falling curve.

Adolescent↗
PubMed1981

The size of the mastoid air cell system among black and white children with middle ear effusion.

The incidence of middle ear disease among black American children is lower than among white children. Many factors may contribute to this difference. The possibility of an anatomical variation regarding the cellularity of the mastoid process was investigated. The size of the mastoid air cell system was measured in black and white children with and without middle ear effusion. A significantly smaller mastoid air cell system was found in the groups with middle ear disease compared to those without disease. No difference between white and black children in diseased as well as non-diseased ears could be demonstrated.

Black People↗
PubMed1978

Physical attractiveness and personality development.

A test of the relationship between physical attractiveness and ego development was completed through an interview study of 294 men and women college students. Ss responded to personality measures assessing identity formation, locus of control, and ego functioning and were rated on facial attractiveness and body form scales. Contrary to the physical attractiveness stereotype, attractive and unattractive Ss did not differ in their personality styles.

Beauty↗
PubMed1977

A comparison of the treatment of trochanteric fractures of the femur by internal fixation with a nail plate and the Ender technique.

In our experience, trochanteric fractures fixed with Ender nails achieved a degree of success similar to those treated by nail plating, but the risk of wound infection was much less with the former method. The results of 78 trochanteric fractures of the femur internally fixed with Ender nails have been analysed and compared with the results in 100 similar patients treated by nail plate fixation. The Ender method has advantages over existing operative methods, in that in our series the infection rate was zero and we found that the operation produced less shock. We consider that this method, although technically more difficult, can be used for most intertrochanteric fractures and merits further trial.

Adult↗
PubMed1976

Plastipore total ossicular replacement prosthesis.

In those ears in which the incus and/or malleus are missing or not suitable, a columella made of high density polyethylene sponge has proven to be very effective. Tissue readily grows into the large pores of this material so that it is well tolerated in the body. During the last six months 54 have been implanted with no rejection so far and a good hearing gain in 43 or 80 percent.

Biocompatible Materials↗