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Lucas M Bachmann

Publications and source records attributed to Lucas M Bachmann.

At least 19 recordsLinked to original sources
PubMed2006

Oral purified bacterial extracts in acute respiratory tract infections in childhood: a systematic quantitative review.

BACKGROUND: Recurrent acute respiratory tract infections (ARTI) are a common problem in childhood. Some evidence suggests a benefit regarding the prevention of ARTI in children treated with the immunomodulator OM-85 BV (Bronchovaxom). METHODS: We summarised the evidence on the effectiveness of the immunomodulator OM-85 BV in the prevention of ARTI in children. We searched randomised comparisons of oral purified bacterial extracts against inactive controls in children with respiratory tract diseases in nine electronic databases and reference lists of included studies. We extracted salient features of each study, calculated relative risks (RR) or weighted mean differences (WMD) and performed meta-analyses using random-effects models. RESULTS: Thirteen studies (2,721 patients) of low to moderate quality tested OM-85 BV. Patients and outcomes differed substantially, which impeded pooling results of more than two trials. Two studies (240 patients) reporting on the number of patients with less than three infections over 6 month of follow-up in children not in day care showed a trend for benefit RR 0.82 (95% CI, 0.65-1.02). One out of two studies examining the number of children not in day care without infections over 4-6 month reported a significant RR of 0.42 (95% CI, 0.21-0.82) whereas the smaller, second study did not [RR 0.92 (95% CI, 0.58-1.46)]. Two studies reporting the number of antibiotic courses indicated a benefit for the intervention arm [WMD 2.0 (95% CI, 1.7-2.3)]. Two out of the three studies showed a reduction of length of episodes of 4-6 days whereas a third study showed no difference between the two groups. CONCLUSION: Evidence in favour of OM-85 BV in the prevention of ARTI in children is weak. There is a trend for fewer and shorter infections and a reduction of antibiotic use.

Child↗
PubMed2006

More medical journals should inform their contributors about three key principles of graph construction.

OBJECTIVES: To identify key principles of graph construction and to review guidance on graph construction provided by medical journals. STUDY DESIGN AND SETTING: Review of a prevailing model of graph comprehension and survey of authors' instructions for all 120 core medical journals as indexed by PubMed. RESULTS: Graph construction should meet three requirements for optimal graph comprehension: Data symbols should be clearly distinguishable to enable their visual detection. Second, the data should be arranged in such a way that estimation of values and important relationships in the data is facilitated, and third, there should be a full explanation of all graph elements and of how the data were obtained. Seven journals (5.8%) provided recommendations on graph construction. Six journals put emphasis primarily on the explanation of graph elements and, to a lesser extent, on the visual detection of data symbols. Recommendations of the seventh journal focused mostly on how to enhance estimation of important relationships. All journals presented single recommendations whose selection seemed unstructured and not based on key principles of graph construction. CONCLUSION: Medical journals should order their instructions according to the three key aspects of graph construction.

Computer Graphics↗
PubMed2006

Predictors of intra- and postoperative complications in laparoscopic colorectal surgery: results of an expert survey.

BACKGROUND: The decision which patient should undergo laparoscopic rather than open colorectal surgery depends on weighing its benefits against its complications. We explored which criteria prognosticate complications in a laparoscopic intervention by assembling experienced visceral surgeons' beliefs. METHODS: A two-round postal survey was conducted: 21 experts in laparoscopic surgery were contacted and asked to list (first round) and weigh (second round) indicators (scale 1-10) they believed predicted intra- or postoperative complications in patients undergoing laparoscopic colorectal surgery. Median ratings and interquartile ranges (IQRs) were calculated. Rates >or=6 and IQRs <or=3 depicted an important prognostic indicator for complications. RESULTS: Thirty-nine intraoperative and 43 postoperative listings and ratings of 19 experts (90%) were available for analysis. The experts depicted three domains of indicators (tumor, comorbidity and related institution). The strongest indicators for intraoperative complications were surgeon's experience (median 9, IQR 8-10) and portal hypertension (median 9, IQR 7-10), and those for postoperative complications were liver cirrhosis Child B/C (median 8, IQR 7.75-10) and experience of the surgeon (median 8, IQR 7-10). CONCLUSION: This survey provides additional evidence of risk indicators for intra- and postoperative complications in patients undergoing laparoscopic colorectal surgery. Whether the identified indicators can be compiled into a prognostic instrument requires confirmation in a properly designed and sized study.

Colon↗
PubMed2006

Accuracy of B-type natriuretic peptide tests to exclude congestive heart failure: systematic review of test accuracy studies.

BACKGROUND: Congestive heart failure (CHF) is a major public health problem. The use of B-type natriuretic peptide (BNP) tests shows promising diagnostic accuracy. Herein, we summarize the evidence on the accuracy of BNP tests in the diagnosis of CHF and compare the performance of rapid enzyme-linked immunosorbent assay (ELISA) and standard radioimmunosorbent assay (RIA) tests. METHODS: We searched electronic databases and the reference lists of included studies, and we contacted experts. Data were extracted on the study population, the type of test used, and methods. Receiver operating characteristic (ROC) plots and summary ROC curves were produced and negative likelihood ratios pooled. Random-effect meta-analysis and metaregression were used to combine data and explore sources of between-study heterogeneity. RESULTS: Nineteen studies describing 22 patient populations (9 ELISA and 13 RIA) and 9093 patients were included. The diagnosis of CHF was verified by echocardiography, radionuclide scan, or echocardiography combined with clinical criteria. The pooled negative likelihood ratio overall from random-effect meta-analysis was 0.18 (95% confidence interval [CI], 0.13-0.23). It was lower for the ELISA test (0.12; 95% CI, 0.09-0.16) than for the RIA test (0.23; 95% CI, 0.16-0.32). For a pretest probability of 20%, which is typical for patients with suspected CHF in primary care, a negative result of the ELISA test would produce a posttest probability of 2.9%; a negative RIA test, a posttest probability of 5.4%. CONCLUSIONS: The use of BNP tests to rule out CHF in primary care settings could reduce demand for echocardiography. The advantages of rapid ELISA tests need to be balanced against their higher cost.

Biomarkers↗
PubMed2006

Sample sizes of studies on diagnostic accuracy: literature survey.

OBJECTIVES: To determine sample sizes in studies on diagnostic accuracy and the proportion of studies that report calculations of sample size. DESIGN: Literature survey. DATA SOURCES: All issues of eight leading journals published in 2002. METHODS: Sample sizes, number of subgroup analyses, and how often studies reported calculations of sample size were extracted. RESULTS: 43 of 8999 articles were non-screening studies on diagnostic accuracy. The median sample size was 118 (interquartile range 71-350) and the median prevalence of the target condition was 43% (27-61%). The median number of patients with the target condition--needed to calculate a test's sensitivity--was 49 (28-91). The median number of patients without the target condition--needed to determine a test's specificity--was 76 (27-209). Two of the 43 studies (5%) reported a priori calculations of sample size. Twenty articles (47%) reported results for patient subgroups. The number of subgroups ranged from two to 19 (median four). No studies reported that sample size was calculated on the basis of preplanned analyses of subgroups. CONCLUSION: Few studies on diagnostic accuracy report considerations of sample size. The number of participants in most studies on diagnostic accuracy is probably too small to analyse variability of measures of accuracy across patient subgroups.

Confidence Intervals↗
PubMed2006

Ocular pulse amplitude in healthy subjects as measured by dynamic contour tonometry.

OBJECTIVES: To test whether dynamic contour tonometry yields ocular pulse amplitude (OPA) measurements that are independent of corneal thickness and curvature, and to assess variables of observer agreement. METHODS: In a multivariate cluster analysis on 223 eyes, the relationship between central corneal thickness, corneal curvature, axial length, anterior chamber depth, intraocular pressure, sex, age, and OPA measurements was assessed. Intraobserver and interobserver variabilities were calculated from repeated measurements obtained from 8 volunteers by 4 observers. RESULTS: The OPA readings were not affected by central corneal thickness (P = .08), corneal curvature (P = .47), anterior chamber depth (P = .80), age (P = .60), or sex (P = .73). There was a positive correlation between OPA and intraocular pressure (0.12 mm Hg/1 mm Hg of intraocular pressure; P<.001) and a negative correlation between OPA and axial length (0.27 mm Hg/1 mm of length; P<.001). Intraobserver and interobserver variabilities were 0.08 and 0.02 mm Hg, respectively, and the intraclass correlation coefficient was 0.89. CONCLUSIONS: The OPA readings obtained with dynamic contour tonometry in healthy subjects are not influenced by the structure of the anterior segment of the eye but are affected by intraocular pressure and axial length. We found a high amount of agreement within and between observers.

Adult↗
PubMed2006

Etiology in a taxonomy of illnesses.

According to what Robert Koch termed the etiological standpoint, illnesses are best understood and controlled by focusing on their causes, including in their definitions and, thus, in the construction of their taxonomies. In some ways flawed, this standpoint has been misunderstood and misapplied. A taxonomy based solely on etiology was an unrealistic dream in the context of 'the bacteriological revolution', and it also is unrealistic in the present context of 'the genetic revolution.' We argue that the illnesses in a taxonomy of them are in some cases best defined directly in terms of their respective somatic anomalies, in some others indirectly by the unique and universal etiology of that anomaly (left unspecified) in a 'deeper' somatic anomaly, and in yet others as a combination of these; and when the somatic anomaly for direct definition remains unknown, it is to be defined indirectly by the clinical syndrome that is its patient-relevant manifestation, possibly in conjunction with a somatic cause. We note, also, that these taxonomic issues have no material bearing on epidemiologists' etiologic research for the knowledge base of community-level preventive medicine.

Disease↗
PubMed2006

Diagnostic value of systematic biopsy methods in the investigation of prostate cancer: a systematic review.

PURPOSE: Several new extended prostate biopsy schemes (greater than 6 cores) have been proposed. We compared the cancer detection rates and complications of different extended prostate biopsy schemes for diagnostic evaluation in men scheduled for biopsy to identify the optimal scheme. MATERIALS AND METHODS: In a systematic review we searched 13 electronic databases, screened relevant urological journals and the reference lists of included studies, and contacted experts. We included studies that compared different systematic prostate biopsy methods using sequential sampling or a randomized design in men scheduled for biopsy due to suspected prostate cancer. We pooled data using a random effects model when appropriate. RESULTS: We analyzed 87 studies with a total of 20,698 patients. We pooled data from 68 studies comparing a total of 94 extended schemes with the standard sextant scheme. An increasing number of cores were significantly associated with the cancer yield. Laterally directed cores increased the yield significantly (p = 0.003), whereas centrally directed cores did not. Schemes with 12 cores that took additional laterally directed cores detected 31% more cancers (95% CI 25 to 37) than the sextant scheme. Schemes with 18 to 24 cores did not detect significantly more cancers. Adverse events for schemes up to 12 cores were similar to those for the sextant pattern. Adverse event reporting was poor for schemes with 18 to 24 cores. CONCLUSIONS: Prostate biopsy schemes consisting of 12 cores that add laterally directed cores to the standard sextant scheme strike the balance between the cancer detection rate and adverse events. Taking more than 12 cores added no significant benefit.

Biopsy↗
PubMed2006

Predicting the risk of hospital admission in older persons--validation of a brief self-administered questionnaire in three European countries.

OBJECTIVES: To validate the Probability of Repeated Admission (Pra) questionnaire, a widely used self-administered tool for predicting future healthcare use in older persons, in three European healthcare systems. DESIGN: Prospective study with 1-year follow-up. SETTING: Hamburg, Germany; London, United Kingdom; Canton of Solothurn, Switzerland. PARTICIPANTS: Nine thousand seven hundred thirteen independently living community-dwelling people aged 65 and older. MEASUREMENTS: Self-administered eight-item Pra questionnaire at baseline. Self-reported number of hospital admissions and physician visits during 1 year of follow-up. RESULTS: In the combined sample, areas under the receiver operating characteristic curves (AUCs) were 0.64 (95% confidence interval (CI)=0.62-0.66) for the prediction of one or more hospital admissions and 0.68 (95% CI=0.66-0.69) for the prediction of more than six physician visits during the following year. AUCs were similar between sites. In comparison, prediction models based on a person's age and sex alone exhibited poor predictive validity (AUC or= 0.5) were 2.3 times as likely (95% CI=2.1-2.6) as low-risk individuals to have a hospital admission, and 2.1 times as likely (95% CI=2.0-2.2) to have more than six physician visits. CONCLUSION: The Pra instrument exhibits good validity for predicting future health service use on a population level in different healthcare settings. Administrative data have shown similar predictive validity, but in practice, such data are often not available. The Pra is likely of high interest to governments and health insurance companies worldwide as a basis for programs aimed at health risk management in older persons.

Aged↗
PubMed2006

Endobronchial ultrasonography for the quantitative assessment of bronchial mural structures in lung transplant recipients.

BACKGROUND: Endobronchial ultrasonography (EBUS) has been shown to be an adequate tool to visualize the laminar structure of the bronchial wall. The purpose of this study was to investigate the potential of EBUS to identify and quantitatively assess bronchial wall structures in lung transplant recipients. METHODS: EBUS was performed with a radial 20-MHz ultrasonic miniprobe in lung transplant recipients undergoing surveillance bronchoscopies. Sequential pictures were taken of the main bronchus (proximal of anastomosis) and proximal right intermedius bronchus or proximal left lower lobe bronchus (distal of anastomosis), respectively. From every localization, five slides were chosen. The quantitative assessment of the digitized pictures was done with the aid of image analysis software. In addition to the comparison of the different layers between patients with and without infection and rejection, respectively, the intraclass correlation coefficients (ICCs) of the different measurements were calculated. RESULTS: From 20 EBUS examinations performed in 10 lung transplant recipients, 200 slides were selected for quantitative assessment. A five-layer composition could be identified in all selected slides. The relative area of layer two (hypoechoic submucosal tissue) of the autologous part was significantly smaller in patients with graft rejection (p = 0.04) compared to patients without rejection, and significantly larger in patients with graft infection (p = 0.02) compared to patients without graft infection. The ICC values were calculated in 50 different slides in a subset of five consecutive patients (0.91, 0.95, 0.88, and 0.91 for layers 1, 2, 3, and 5 of the autologous and 0.70, 0.92, 0.88, and 0.84 for the allogeneic parts, respectively). CONCLUSIONS: EBUS enables to discriminate different layers of the bronchi in humans and to measure the thickness of these layers in a reproducible fashion. Therefore, EBUS may be used to investigate and quantify inflammatory alterations of bronchial wall structures in vivo.

Adult↗
PubMed2006

Patients' satisfaction with the preoperative informed consent procedure: a multicenter questionnaire survey in Switzerland.

OBJECTIVE: To assess patients' satisfaction with the preoperative informed consent procedure in obstetrics and gynecology. PATIENTS AND METHODS: Between March 2001 and April 2002, patients from 11 Swiss hospitals, representing 3 linguistic areas of Switzerland, were given a questionnaire and a standardized operation-specific leaflet and engaged in a structured conversation. The questionnaire and operation-specific leaflet were designed in collaboration with the Swiss Patient Organization, the judiciary service of the Swiss Medical Association, and the Swiss Society of Obstetrics and Gynecology. RESULTS: A total of 3888 (56%) of 6970 women received the questionnaire and were enrolled in the study. Most of the patients considered the written and oral information to be good or excellent, and more than 80% did not desire further written information. Forty-five percent would have preferred to receive this structured Information the same day the decision to undergo an invasive procedure was made, and mere than half of the patients were reassured by the information provided. However, in 7% anxiety increased. In the multivariate analysis, Turkish (odds ratio [OR], 6.7; 95% confidence Interval [CI], 2.0-22.4; P=-.002) and Serbo-Croat (OR, 8.0; 95% CI, 2.4-27.4; P=.001) language and a poor rating of the written description of the planned operation (OR, 3.1; 95% CI, 1.1-9.0; P=-.03) were the only variables significantly associated with discontent. CONCLUSIONS: The combined written and oral preoperative information presented is well adapted to patients' Informative wishes and needs; it allows for a structured conversation, facilitates documentation, and offers valid legal proof that adequate information has been provided. Therefore, close collaboration between the national patient organization and the expert Judiciary and medical societies of the corresponding country is strongly recommended to Improve the Informed consent procedure.

Adolescent↗
PubMed2005

Does the Angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism modify the response to ACE inhibitor therapy?--A systematic review.

BACKGROUND: Pharmacogenetic testing to individualize ACE inhibitor therapy remains controversial. We conducted a systematic review to assess the effect modification of the insertion/deletion (I/D) polymorphism of the ACE gene on any outcome in patients treated with ACE inhibitors for cardiovascular and/or renal disease. METHODS: Our systematic review involved searching six electronic databases, then contacting the investigators (and pharmaceutical industry representatives) responsible for the creation of these databases. Two reviewers independently selected relevant randomized, placebo-controlled trials and abstracted from each study details on characteristics and quality. RESULTS: Eleven studies met our inclusion criteria. Despite repeated efforts to contact authors, only four of the eleven studies provided sufficient data to quantify the effect modification by genotypes. We observed a trend towards better response to ACE inhibitors in Caucasian DD carriers compared to II carriers, in terms of blood pressure, proteinuria, glomerular filtration rate, ACE activity and progression to end-stage renal failure. Pooling of the results was inappropriate, due to heterogeneity in ethnicity, clinical domains and outcomes. CONCLUSION: Lack of sufficient genetic data from the reviewed studies precluded drawing any convincing conclusions. Better reporting of genetic data are needed to confirm our preliminary observations concerning better response to ACE inhibitors among Caucasian DD carriers as compared to II carriers.

Journal Article↗
PubMed2005

A randomized trial of ways to describe test accuracy: the effect on physicians' post-test probability estimates.

BACKGROUND: Some people believe that likelihood ratios provide diagnostic information that is more useful than sensitivity and specificity estimates. OBJECTIVE: To assess how physicians' estimates about probability of illness are affected by the presentation of a diagnostic test's value as an estimate of sensitivity and specificity versus a likelihood ratio or an inexact numerical graphic. DESIGN: Random assignment of vignettes with different presentation formats of diagnostic test accuracy. SETTING: Auditorium at a continuing medical education conference. PARTICIPANTS: 183 physicians. INTERVENTION: After estimating probabilities of 6 common illnesses described in patient vignettes, physicians reviewed pertinent test results presented in 1 of 3 formats. MEASUREMENTS: Physicians' probability estimates of illness before and after receiving test information, and post-test probability estimates based on the Bayes theorem. RESULTS: Absolute percentage point differences between the physicians' estimated and the Bayes-based post-test probabilities varied from -7 to 31, from -7 to 28, and from 1 to 29 for the sensitivity and specificity, likelihood ratio, and graphical groups, respectively. Mean differences of probability estimates between the sensitivity and specificity and the likelihood ratio groups were small for all vignettes (-2 to 3 percentage points; summary mean z value across the 6 vignettes, 0.04 [95% CI, -0.14 to 0.21]). LIMITATIONS: The small pool of participants (who were potentially selected) and the limited number of vignettes prevented a more detailed analysis of relationships between the interpreted strength of diagnostic evidence and estimations of illness probability. CONCLUSIONS: These findings suggest that presenting diagnostic test accuracy with likelihood ratios does not affect some physicians' estimates of illness probability compared with presenting diagnostic test results as sensitivity and specificity.

Adult↗
PubMed2005

Ocular pulse amplitude after trabeculectomy.

BACKGROUND: The ocular pulse amplitude (OPA) is the difference between the minimum and maximum values of the pulsatile intraocular pressure (IOP) wave contour. The OPA depends on ocular perfusion and IOP, which are both affected by a trabeculectomy (TE). The aim of this study was to investigate how the OPA changes after TE and whether an early change in OPA can be used as a prognostic marker for a successful long-term outcome. METHODS: Fourteen consecutive patients (26-84 years old) with medically uncontrolled primary open-angle or pseudoexfoliation glaucoma were included in the study. IOP and OPA were measured with a dynamic contour tonometer before and after TE on days -1, +1, +7, +14, +21, +28, +42, +56, +70, and +84. The OPA of the contralateral eye was used to control for variations in systemic haemodynamics. TE was regarded as successful if a persistent drop in IOP of at least 20% without the use of IOP-lowering treatment was achieved. Data were analysed using receiver operating characteristic curves, Kaplan-Meier survival curves and Mann-Whitney two-sample analysis. RESULTS: Five out of 14 TEs had an entirely successful outcome. The other 9 patients required additional interventions such as suturolysis, needling of subconjunctival scar tissue and antimetabolite injections during the 3-month period after the TE. On the first day after surgery, OPA decreased in 12 patients and increased in 2 patients compared with the preoperative measurements. In the 5 patients with a successful long-term outcome, OPA dropped by 3.38+/-1.79 mmHg (mean+/-SE), whereas the initial OPA drop in those cases that required additional interventions was 0.62+/-1.81 mmHg only (p<0.01). IOP dropped by 13.10+/-2.14 mmHg in the successful group and by 5.84+/-2.51 mmHg in the unsuccessful group (p=0.19). Kaplan-Meier estimates of survival showed that patients with an initial OPA drop of more than 2.0 mmHg had a significantly better chance of an entirely uncomplicated 3-month outcome after TE than patients with an initial OPA drop of less than 2.0 mmHg (log rank p<0.01). CONCLUSION: This pilot study indicates that an early drop in OPA of more than 2.0 mmHg after TE may be a good prognostic parameter for successful long-term control of IOP.

Adult↗
PubMed2005

Consequences of different diagnostic "gold standards" in test accuracy research: Carpal Tunnel Syndrome as an example.

Test accuracy studies assume the existence of a well-defined illness definition and clear-cut diagnostic gold standards or reference standards. However, in clinical reality illness definitions may be vague or a mere description of a set of manifestations, mostly clinical signs and symptoms. This can lead to disagreements among experts about the correct classification of an illness and the adequate reference standard. Using data from a diagnostic accuracy study in carpal tunnel syndrome, we explored the impact of different definitions on the estimated test accuracy and found that estimated test performance characteristics varied considerably depending on the chosen reference standard. In situations without a clear-cut illness definition, randomized controlled trials may be preferable to test accuracy studies for the evaluation of a novel test. These studies do not determine the diagnostic accuracy, but the clinical impact of a novel test on patient management and outcome.

Carpal Tunnel Syndrome↗
PubMed2005

The accuracy of maternal anthropometry measurements as predictor for spontaneous preterm birth--a systematic review.

OBJECTIVE: To assess the accuracy with which antenatal maternal anthropometric measurements predict the risk spontaneous preterm birth. STUDY DESIGN: (1) DATA SOURCES: Studies were identified without language restrictions from MEDLINE, EMBASE, PASCAL, BIOSIS, the Cochrane Library, MEDION, National Research Register, SCISEARCH and Conference Papers, and manual searching of bibliographies of known primary and review articles, and contact with authors. (2) STUDY SELECTION AND DATA EXTRACTION: Studies were selected if they used antenatal maternal anthropometric features (pre-pregnancy weight, maternal pregnancy weight gain and maternal height) to predict spontaneous preterm birth. Two reviewers independently selected studies and extracted data on their characteristics, quality and accuracy. Accuracy data were used to form 2 x 2 contingency tables of the maternal anthropometric test results with spontaneous preterm birth as the reference standard. (3) DATA SYNTHESIS: Heterogeneity assessments were carried out to aid the decision regarding pooling of the accuracy results. Likelihood ratios for positive (LR+) and negative (LR-) test results were calculated, and summary estimates were produced in absence of heterogeneity of the accuracy results. RESULTS: There were eight primary accuracy articles that met the selection criteria, which included a total of 122,647 asymptomatic women. There were six studies on pre-pregnancy weight where five measured the body mass index (BMI) and one used an arbitrary measure. There were four studies on the adequacy of pregnancy weight gain and two studies on maternal height as a predictor for the risk of preterm birth. One article contributed three studies, while two articles provided two studies each. The commonest reference standard used was birth before 37 weeks' gestation. None of the studies fulfilled the ideal test accuracy study criteria. There was heterogeneity in the accuracy results of pre-pregnancy BMI but not in the adequacy of weight gain. All three maternal anthropometric features were poor predictors of preterm labour. Pre-pregnancy BMI is a poor predictor of preterm birth before 37 weeks' gestation (LR+ that ranged from 0.96 (95% confidence interval (CI) 0.66-1.40) to 1.75 (95% CI 1.33-2.31)) as are the adequacy of pregnancy weight gain (summary LR+ of 1.81, 95% CI 1.45-2.30) and short maternal height (LR+ of 1.79 (95% CI 1.27-2.52). CONCLUSION: Routine antenatal maternal anthropometric measurements are not useful in predicting the risk of preterm birth before 37 weeks' gestation. Further studies should address their use in combination with other test but need to use a more clinically appropriate reference standard of preterm birth, such as birth before 32-34 weeks' gestation, and improve on the quality of study design.

Anthropometry↗
PubMed2005

Diagnostic value of sonography in patients with suspected carpal tunnel syndrome: a prospective study.

OBJECTIVE: To determine the diagnostic value of sonography in patients with suspected carpal tunnel syndrome (CTS). METHODS: We conducted a prospective study of 110 wrists in 74 consecutive patients with suspected CTS who had been referred to a tertiary care center. We determined the largest cross-sectional area of the median nerve at the carpal tunnel. Because of the lack of a universally accepted reference standard, we first examined the association of sonography with nerve conduction. Then, we compared sonography with a reference standard based on the combination of nerve conduction studies and signs and symptoms. Sonography and reference standard tests were performed independently and interpreted under blinded conditions. Based on a fitted receiver operating characteristic curve, we estimated likelihood ratios (LRs) and posttest probabilities for different cutoffs. RESULTS: There was a high concordance between sonography and nerve conduction. Based on the combined reference standard, a cutoff of 10 mm(2) resulted in approximately equal sensitivity and specificity, but only moderate LRs. A cutoff of <8 mm(2) had satisfactory power to rule out CTS: the fitted-negative LR was 0.13. Conversely, a cutoff of > or =12 mm(2) had excellent power to rule in CTS, with a fitted-positive LR of 19.9. For nerves > or =12 mm(2) and a pretest probability of 70% expected in patients with suspected CTS in tertiary care, we found a posttest probability of CTS of 98%. CONCLUSION: Depending on setting and purpose, different cutoff values for the largest cross-sectional area may be used to accurately rule in or rule out CTS. Using sonography as a first-line test may cost-effectively reduce the number of nerve conduction studies in patients with suspected CTS. A large-scale, randomized controlled trial is required to determine the effects of sonography on clinical outcomes, the number of nerve conduction studies performed, and the total cost.

Adult↗