Biomedical subjects

Robert B Keller

Publications and source records attributed to Robert B Keller.

6 recordsLinked to original sources

PubMed2003

The Maine-Seattle back questionnaire: a 12-item disability questionnaire for evaluating patients with lumbar sciatica or stenosis: results of a derivation and validation cohort analysis.

STUDY DESIGN: Analysis of health-related quality of life data obtained from a prospective cohort study of patients with sciatica due to an intervertebral disc herniation or lumbar spinal stenosis. OBJECTIVE: To derive and validate a shortened version of a previously validated 23-item modification of the Roland-Morris Disability Questionnaire. SUMMARY OF BACKGROUND DATA: For patients with low back pain, improving health-related quality of life is often the main goal of therapy. The Roland-Morris Disability Questionnaire is one of the best validated and most frequently used back-specific functional status measures. A shortened version may permit more widespread use in clinical and research settings. METHODS: Data from 507 patients with sciatica enrolled in the Maine Lumbar Spine Study were used to derive a shortened version of a 23-item modification of the original Roland-Morris Disability Questionnaire using qualitative and cluster analysis techniques. The internal consistency, construct validity, reproducibility, and responsiveness in detecting change over a 3-month period for a new 12-item scale was compared to the original 23-item scale. The 12-item scale was then validated in an independent cohort of 148 patients with lumbar spinal stenosis. RESULTS: Internal consistency was very good but modestly lower for the 12-item instrument compared to the 23-item original scale. Reproducibility over a 3-month interval was good and did not differ between the 12-item and original scale. Findings from the validation cohort were similar or better than the derivation cohort. A high degree of construct validity with patient-reported symptoms was demonstrated for the 12-item and original scales. The responsiveness and interpretability of the 12-item scale over 3 months was excellent and comparable to the original scale. Responsiveness assessed in patients with lumbar spinal stenosis in the independent validation cohort showed consistent findings compared to patients with a disc herniation in the derivation cohort. CONCLUSIONS: This short, simple, self-administered 12-item back-specific functional status questionnaire performed extremely well in comparison with the original 23-item scale. If validated in additional study populations, this new questionnaire may be useful in the clinical setting as a way for providers to prospectively compare their outcomes of care to other patient populations, and to study treatment effectiveness.

Adult↗

PubMed2003

Point of view.

Explore the source record for details and available documents.

Humans↗

PubMed2003

Do osteopathic physicians differ in patient interaction from allopathic physicians? An empirically derived approach.

Colleges of osteopathic medicine teach osteopathic principles, which provide a different approach to and interaction with patients than principles taught in allopathic medical schools. The authors examined whether osteopathic primary care physicians' interactions with patients reflect the principles of osteopathic medicine when compared with allopathic physicians' interactions. The principles of osteopathic medicine were adapted to elements that could be measured from an audio recording. This 26-item index was refined with two focus groups of practicing osteopathic physicians. Fifty-four patient visits to 11 osteopathic and 7 allopathic primary care physicians in Maine for screening physicals, headache, low back pain, and hypertension were recorded on audiotape and were dual-abstracted. When the 26-item index of osteopathic principles was summed, the osteopathic physicians had consistently higher scores (11 vs. 6.9; P = .01) than allopathic physicians, and visit length was similar (22 minutes vs. 20 minutes, respectively). Twenty-three of the 26 items were used more commonly by the osteopathic physicians. Osteopathic physicians were more likely than allopathic physicians to use patients' first names; explain etiologic factors to patients; and discuss social, family, and emotional impact of illnesses. In this study, osteopathic physicians were easily distinguishable from allopathic physicians by their verbal interactions with patients. Future studies should replicate this finding as well as determine whether it correlates with patient outcomes and satisfaction.

Female↗

PubMed2002

Editorial.

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Humans↗

PubMed2002

Longer distal motor latency predicts better outcomes of carpal tunnel release.

The association of preoperative median nerve distal latencies with surgical outcomes of carpal tunnel release is unclear. A total of 109 surgically treated workers with carpal tunnel syndrome across the state of Maine completed questionnaires assessing preoperative levels of symptom and functional limitations and general physical health (SF-12). A second questionnaire assessed the 6-month postoperative outcomes of symptom severity, functional limitations, and satisfaction with surgery. Univariate analyses indicated that longer preoperative distal motor and sensory latencies were associated with less postoperative levels of symptom, less postoperative functional limitations, and more satisfaction with surgery. The associations persisted in multiple linear regression analysis; however, better general health preoperatively was a better predictor of favorable outcomes. The results suggest that workers with prolonged preoperative distal motor latencies and who are in good general health preoperatively have a higher rate of successful carpal tunnel release surgery.

Adult↗

PubMed2002

Criteria for approximating certain microgravity flow boiling characteristics in Earth gravity.

The forces governing flow boiling, aside from system pressure, are buoyancy, liquid momentum, interfacial surface tensions, and liquid viscosity. Guidance for approximating certain aspects of the flow boiling process in microgravity can be obtained in Earth gravity research by the imposition of a liquid velocity parallel to a flat heater surface in the inverted position, horizontal, or nearly horizontal, by having buoyancy hold the heated liquid and vapor formed close to the heater surface. Bounds on the velocities of interest are obtained from several dimensionless numbers: a two-phase Richardson number, a two-phase Weber number, and a Bond number. For the fluid used in the experimental work here, liquid velocities in the range U = 5-10cm/sec are judged to be critical for changes in behavior of the flow boiling process. Experimental results are presented for flow boiling heat transfer, concentrating on orientations that provide the largest reductions in buoyancy parallel to the heater surface, varying +/-5 degrees from facing horizontal downward. Results are presented for velocity, orientation, and subcooling effects on nucleation, dryout, and heat transfer. Two different heater surfaces were used: a thin gold film on a polished quartz substrate, acting as a heater and resistance thermometer, and a gold-plated copper heater. Both transient and steady measurements of surface heat flux and superheat were made with the quartz heater; only steady measurements were possible with the copper heater. R-113 was the fluid used; the velocity varied over the interval 4-16cm/sec; bulk liquid subcooling varied over 2-20 degrees C; heat flux varied over 4-8W/cm(2).

Journal Article↗