Biomedical subjects

J Hartzel

Publications and source records attributed to J Hartzel.

8 recordsLinked to original sources

PubMed2000

Strategies for comparing treatments on a binary response with multi-centre data.

This paper surveys methods for comparing treatments on a binary response when observations occur for several strata. A common application is multi-centre clinical trials, in which the strata refer to a sample of centres or sites of some type. Questions of interest include how one should summarize the difference between the treatments, how one should make inferential comparisons, how one should investigate whether treatment-by-centre interaction exists, how one should describe effects when interaction exists, whether one should treat centres and centre-specific treatment effects as fixed or random, and whether centres that have either 0 successes or 0 failures should contribute to the analysis. This article discusses these matters in the context of various strategies for analysing such data, in particular focusing on special problems presented by sparse data.

Administration, Topical↗

PubMed1998

Continuous passive motion after repair of the rotator cuff. A prospective outcome study.

Despite the apparent success of continuous passive motion after soft-tissue procedures or joint replacements, its effect after repair of the rotator cuff is still unknown. The purpose of this prospective, randomized outcome study was to compare the results of continuous passive motion with those of manual passive range-of-motion exercises after repair of the rotator cuff. Thirty-one patients (thirty-two rotator cuffs) were randomly assigned to one of two types of postoperative management: continuous passive motion (seventeen patients) or manual passive range-of-motion exercises (fifteen patients). There were seventeen women and fourteen men, and the mean age was sixty-three years (range, thirty to eighty years). The patients were followed for a mean of twenty-two months (range, six to forty-five months). Five tears of the rotator cuff were small, eighteen were medium, and nine were large. All of the operations were performed by one surgeon. The patients who were managed with continuous passive motion used the device for the first four weeks postoperatively. The patients who were managed with manual passive range-of-motion exercises were assisted by a trained relative, friend, or home-care nurse. After the four-week period, the two groups were managed similarly for two to five months. According to the Shoulder Pain and Disability Index, a valid and reliable self-administered questionnaire, the treatment was extremely successful in both groups. The overall score was excellent for twenty-seven shoulders (84 per cent), good for two (6 per cent), fair for two (7 per cent), and poor for one (3 per cent). With the numbers available, we could detect no significant differences (p > 0.05) between the two groups with respect to the score according to the Index, pain (according to a visual-analog scale), range of motion, or isometric strength. Manual passive range-of-motion exercises were more cost-effective than continuous passive motion. The limited number of physical-therapy visits associated with the manual passive range-of-motion exercises in the present study appeared to be more cost-effective than a traditional physical-therapy schedule of three visits per week. Postoperative therapy with continuous passive motion or manual passive range-of-motion exercises appears to yield favorable results after repair of a small, medium, or large tear of the rotator cuff.

Adult↗

PubMed1996

Population-averaged and cluster-specific models for clustered ordinal response data.

We compare population-averaged and cluster-specific models for clustered ordinal data. We consider generalized estimating equations and constrained equations maximum likelihood estimation of population-averaged cumulative logit regression models, and mixed effects estimation of cluster-specific cumulative logit regression models. A previously reported relationship between population-averaged and cluster-specific parameters for the binary logistic link appears to hold for analogous parameters under the cumulative logit link. We address these issues in the context of data from two cross-over clinical trials.

Chi-Square Distribution↗

PubMed1995

Percutaneous biopsy of the liver and kidney by using coaxial technique: adequacy of the specimen obtained with three different needles in vitro.

OBJECTIVE: The coaxial biopsy technique was evaluated with respect to the quality of specimens obtained from the liver and kidneys in vitro on sequential biopsies at the same site with each of three different biopsy needles. MATERIALS AND METHODS: For each of three different biopsy needles (aspiration 18-gauge Chiba, 18-gauge Sure-Cut, and 18-gauge Biopty), 30 sites (15 liver, 15 kidney) were selected for in vitro coaxial biopsy. At each site, an introducer was placed, through which three sequential biopsies were done. Blinded histopathologic analysis was used to grade the quality of specimens on a scale from 0 (no tissue) to 3 (best) for three criteria: adequacy of tissue for diagnosis, tissue fragmentation, and crush artifact. The overall score was the sum of the scores for the three individual criteria and ranged from 0 (no tissue) to 9 (best). RESULTS: Using an 18-gauge Chiba needle and coaxial technique, we found no significant reduction in specimen quality when we did multiple aspiration biopsies at the same site. However, no tissue was obtained (zero biopsy) from a large number of aspiration biopsies done with the Chiba needle, ranging from 24 of 30 for the first biopsy to 17 of 30 for the third biopsy. Specimen quality was reduced somewhat between the first and third biopsies when the 18-gauge Sure-Cut and Biopty needles were used. With the Sure-Cut needle, this reduction in quality was significant (p = .009) and was primarily related to increased tissue fragmentation and crushing. The reduction in quality with multiple biopsy attempts was less severe with the Biopty needle/gun. Although the mean score decreased from 6.6 for the first biopsy to 5.5 for the third biopsy, this reduction was not significant (p = .06). In addition, the Biopty gun, unlike the other two needles, had few zero biopsies. CONCLUSION: The use of a coaxial technique with an 18-gauge Biopty needle enables collection of a large amount of high-quality tissue for histopathologic analysis with a minimum number of failed biopsies as compared with the 18-gauge Chiba needle and the 18-gauge Sure-Cut needle.

Biopsy, Needle↗

PubMed1995

Informed consent forms for clinical and research imaging procedures: how much do patients understand?

OBJECTIVE: Informed consent is often obtained in diagnostic radiology, especially for invasive procedures and research studies. However, how much the average patient actually understands of the information contained in these informed consent forms is uncertain. A cross section of the clinical and research consent forms used in diagnostic radiology was evaluated with respect to their readability, that is, how easy or difficult they were to understand. MATERIALS AND METHODS: The active members of the Association of University Radiologists were solicited to provide copies of their clinical and research informed consent forms. After eliminating duplicates, we digitized the forms and used a computer program to evaluate their readability. Computer readability assessment allows the rapid study of an entire document by a variety of readability formulas (Flesch-Kincaid, Flesch, and Fog). RESULTS: We received 549 different consent forms from 156 institutions; 265 forms were intended primarily for clinical use and 284 were used primarily for research. Although the clinical consent forms were only 41% as long as those for research, a statistical comparison showed them to be harder to understand (p < 0.005). The mean readability score (years of education needed to understand) for all 265 clinical consent forms was 15 versus 12 for the research forms. The most complex clinical consent forms were those written by hospitals for any type of procedure or operation (the generic surgical or procedure consent form). On average, this type of clinical consent form required at least a college education to understand. CONCLUSION: Our results show that most consent forms used in radiology practice are too complex for the average patient to understand. The increased complexity of clinical consent forms, especially the generic surgical or procedure consent forms, as compared with research consent forms, is probably a product of the decreased attention given to the clinical consent forms, the bureaucratic and legal requirements of the clinical forms, and the lack of physician participation in preparing these forms.

Cognition↗

PubMed1994

The effect of informed consent on the level of anxiety in patients given i.v. contrast material.

OBJECTIVE: A common reason given for not obtaining informed consent before the use of IV contrast material is that the anxiety created by informing patients of potential reactions will increase the possibility of their occurring. However, the idea that this is possible is debatable, and no study of this subject has used a standardized anxiety index. Accordingly, using the State-Trait Anxiety Inventory, we assessed the anxiety level among patients about to have an IV contrast procedure and measured the effect of informing them of the risks associated with the use of contrast material. SUBJECTS AND METHODS: Approximately 2050 adult outpatients at three separate medical centers were solicited for participation in this study. Each of the 1251 patients who volunteered to participate was placed into one of six groups. The majority were patients who were awaiting the injection of either ionic or nonionic contrast material and who were or were not informed of the risks associated with the use of IV contrast material. The last two groups were generally healthy outpatients reporting for routine X-rays who were not awaiting IV contrast administration but who were informed of the risks associated with the use of ionic and nonionic contrast material. Each patient informed of the risks was asked to read a standardized consent form, and all patients completed a standardized anxiety index. RESULTS: Patients who were informed of the risks associated with IV contrast material did not have measurably increased anxiety, and they did not have an increased prevalence of adverse reactions. Indeed, the only patients who had statistically significant increased anxiety compared with the other groups were among those awaiting the injection of ionic contrast material who were not informed of the risks (p = .04). The majority (51-78%) of patients in all six groups had measurable elevated anxiety scores. CONCLUSION: We conclude that it is not justified to fail to obtain informed consent in order to avoid anxiety-induced adverse reactions to IV contrast material. The majority of patients awaiting injection of IV contrast material have measurable increased anxiety levels regardless of whether they are informed of its risks.

Anxiety↗

PubMedDate not supplied

Multiple fine-needle biopsies using a coaxial technique: efficacy and a comparison of three methods.

PURPOSE: Compare the success of three coaxial fine-needle biopsy techniques in obtaining multiple cytologic specimens of high quality. METHODS: For each of three different biopsy needle and technique combinations (aspiration: 22-gauge Chiba; capillary: 22-gauge Chiba; 22-gauge Autovac aspiration biopsy gun), 30 sites (15 liver, 15 kidney) were selected for coaxial fine-needle biopsy in cadaveric liver and kidneys. For each coaxial technique, three sequential biopsies were performed through an 18-gauge coaxial needle at each of multiple sites. The quality of the resultant 270 specimens was graded by a blinded cytopathologist using a previously published grading scheme. RESULTS: Using the coaxial technique, there was no significant dropoff in the cytologic specimen quality among the first, second, and third biopsies at a specific site, regardless of the order of the techniques/needles used. This was true for organs, the overall data, and for the individual five grading criteria. There was, however, a significant difference among the biopsy techniques themselves. Though there was no difference in the quality of cytopathologic specimen obtained with the Autovac aspiration gun and the aspiration technique with a 22-gauge Chiba needle, both were statistically better than the nonaspiration, capillary technique utilizing a 22-gauge needle (p = 0.0001). CONCLUSION: The use of a coaxial technique with a fine-needle, 22-gauge biopsy offers unique advantages in obtaining a nearly unlimited amount of high-quality material for cytopathologic analysis. In this study, no dropoff was found in specimen quality with subsequent biopsies.

Biopsy, Needle↗

PubMedDate not supplied

Dynamic versus static grip strength: how grip strength changes when the wrist is moved, and why dynamic grip strength may be a more functional measurement.

The synergistic relationship between wrist/forearm range of motion (ROM) and grip strength (GS) is arguably one of the most important aspects of hand function. Clinically, GS is measured with the wrist in a standardized static position, and the results of such tests have been deemed valid and reliable. The question remains, however, whether this static GS (SGS) measurement is an accurate indication of how an individual functionally grips objects--that is, most functional tasks require the fingers to grasp an object forcibly while moving the proximal joints such as the wrist and forearm. Therefore, further analysis of an individual's dynamic GS (DGS) during wrist/forearm movements may improve the clinician's understanding of hand function and provide more pertinent guidelines for assessing functional gripping, e.g., for vocational and avocational tasks and in designing workstations. The purpose of this study is twofold: to describe and assess a DGS testing device that utilizes optically encoded gyroscopes and a strain-gauge dynamometer to simultaneously measure GS and wrist/forearm position over real time; and to assess and compare grip force production differences in SGS and DGS in uninjured wrists, using this novel device. Twenty-nine uninjured wrists of men (n = 15) and women (n = 14)--age range, 21 to 43 years--were tested with the DGS device. Subjects were excluded if they had any previous wrist/forearm fracture, pain, or limitation of motion. The DGS device was designed and fabricated with two optically encoded gyroengines, a vertical gyroscope with two axes for measuring flexion/extension and radial/ulnar deviation, and a directional gyroscope with one axis for measuring supination/pronation, mounted on a strain-gauge dynamometer. The signals from the gyroscopes and dynamometer were processed by means of a data aquisition board and analog-to-digital circuitry and collected on a 486-MHz computer. The methods included repeated testing of each gyroscope axis to known angular measurements, and randomly assigned maximal gripping trials from the 29 subjects. The standard deviation of gyroengines is 1 degree to 2 degrees for each ROM axis. Maximal DGS is significantly less (mean 14%) than SGS, and SGS is 29% less than DGS at the same three-dimensional ROM positions. Gyroengines are feasible three-dimensional tracking devices that can be used to monitor wrist/forearm ROM in conjunction with GS.

Adult↗