Biomedical subjects

W P Weber

Publications and source records attributed to W P Weber.

4 recordsLinked to original sources

PubMed2006

Propensity scores and the surgeon.

BACKGROUND: Evidence-based surgery has been established as a cornerstone of good clinical practice, promising to improve the treatment of patients and the quality of surgical education. However, evidence-based surgery requires dedicated clinicians trained to perform methodologically sound clinical investigations. Statistical knowledge is therefore invaluable. Surgical studies often cannot be randomized. Propensity scores offer a powerful alternative to multivariable analysis in the assessment of observational, non-randomized surgical studies. Unfortunately, many surgeons are unaware of this important analytical approach that has gained increasing stature in medical research. Thus, propensity score analyses are not used often in surgical studies. OBJECTIVE: The purpose of this paper is to provide a comprehensive overview of propensity score analysis, allowing the surgeon to understand the role, advantages and limitations of propensity scores, boosting their development in surgical investigations.

Confounding Factors, Epidemiologic↗

PubMed2001

Fractionation of moderate molecular weight polysiloxanes by centrifugal TLC.

Fractionation of polydispersed polysiloxanes (1-2 g) into narrow molecular weight fractions has been achieved by a rapid (30-60 min) convenient process, using the Cyclograph Centrifugal Chromatography System. These narrow molecular weight poly(dimethylsiloxane) fractions can be used as secondary standards for GPC.

Centrifugation↗

PubMed2001

Advanced breast biopsy instrumentation for the evaluation of impalpable lesions: a reliable diagnostic tool with little therapeutic potential.

OBJECTIVE: To assess the potential of advanced breast biopsy instrumentation (ABBI) to clarify the diagnosis of impalpable mammographic lesions and to remove the entire malignant lesions with clear margins. DESIGN: Prospective assessment in a consecutive series of patients. SETTING: University hospital, Basel, Switzerland. SUBJECTS: 139 patients presenting with 144 impalpable microcalcifications or solid nodular densities evident on screening and follow-up mammograms that were suspicious of malignancy. MAIN OUTCOME MEASURES: Feasibility, sensitivity, efficiency in obtaining definitive diagnoses in an outpatient clinic under local anaesthesia, feasibility of complete removal of a primary malignancy, and intervention-related morbidity. RESULTS: The ABBI procedure was successful in 135/144 (94%); an accurate diagnosis was made in 129/130 patients followed up (99%), sensitivity for malignant lesions was 31/32 (97%) and there were 2 complications (2%). Margins of the biopsy cylinder contained a malignant lesion in 26/31 (84%). CONCLUSIONS: Excisional biopsy using the ABBI system is a reliable diagnostic tool with a low morbidity. As in other published series margins were often not clear of tumour and therefore the therapeutic use of the ABBI procedure is limited.

Adult↗

PubMed2000

[The Advanced Breast Biopsy Instrumentation (ABBI) for evaluation of mammographically suspicious, non-palpable findings of the breast: a reliable diagnosis with minor therapeutic potential].

BACKGROUND: Stereotactic biopsy techniques supersede conventional hook-wire localization followed by open excision to clarify the dignity of nonpalpable mammographic lesions. The advanced breast biopsy instrumentation (ABBI) allows stereotactically guided excision of a specimen up to 20 mm in diameter on an outpatient basis under local anaesthesia. METHODS: Demographic information, mammographic and pathological findings, complications, subsequent interventions and sensitivity as well as efficiency of a series of 144 planned ABBI procedures were documented (largest published single institution series). RESULTS: The ABBI procedure was successfully performed in 93.8% (135/144); accurate diagnosis was made in 99.3% (134/135), sensitivity for malignant lesions was 96.9% (31/32) and morbidity was 1.5%. Consistent with other published series margins of the biopsy cylinder containing a malignant lesion were involved in 83.9% (26/31). CONCLUSIONS: Excisional biopsy using the ABBI system is a reliable diagnostic tool with a low incidence of morbidity. The therapeutic use is of limited potential.

Adult↗