Inguinal hernia repair among men: development and validation of a preoperative risk score for persistent postoperative pain.

PURPOSE: Persistent postoperative pain (PPP) is a prevalent complication after inguinal hernia repair. The aim of this study was to develop and validate a preoperative risk score for PPP. METHODS: We developed the risk score based on a cohort of 2,508 Danish men, who answered a questionnaire six months after inguinal hernia repair performed 2015-2016. PPP was defined as a numerical rating scale score ≥ 2 during activity six months postoperatively. Logistic regression analyses were undertaken to determine statistically significant predictors of PPP. Univariable analysis selected potential predictors with a p value ≤ 0.20, and a subsequent multivariable model was built using backward elimination with a criterion of p value < 0.10. We created a risk score based on the ß coefficients of the multivariable model. The risk score was validated internally using Hosmer-Lemeshow goodness of fit test, calibration belt test, and receiver operating characteristic curve analyses with 95% confidence intervals based on the bootstrap analysis. External validation was performed in a cohort of 293 men recruited preoperatively. RESULTS: Predictors of PPP were age 18-49 and 50-59 (versus ≥ 60) years (p < 0.001), total load lifted > 1,000 kg/day (p = 0.001), working in a bent-over position > 1 h/day (p < 0.001), leisure-time physical activity < 2 h/week (p = 0.009), increasing body mass index (per unit) (p < 0.003), and repair of recurrent hernia (p = 0.001).The preoperative risk score predicted risks of 6-61% in the development population. The model showed good internal and external validity. CONCLUSION: The results suggest that the risk of PPP after inguinal hernia repair can be predicted using a preoperative risk score.

Occupational mechanical exposures and reoperation after first-time inguinal hernia repair: a prognosis study in a male cohort.

PURPOSE: The aim of this study was to evaluate exposure-response relationships between occupational mechanical exposures and risk of reoperation after inguinal hernia repair. METHODS: Using register information, we identified all men born in Denmark 1938-1988, who had their first inguinal hernia repair 1998-2008, and who were 18-65 years old and active in the labour market at the time of surgery. The Danish Hernia Database provided information on repairs and reoperations. We used registered occupational codes and a job exposure matrix based on experts' ratings to estimate total load lifted per day, frequency of heavy lifting, and number of hours per day spent standing/walking. We also obtained register information on sickness absence. Multivariable Cox regression analysis was used. RESULTS: The cohort comprised 34,822 patients. We did not reveal exposure-response relationships between occupational mechanical exposures and the hazard ratio (HR) of reoperation. The percentage of patients with >2 weeks of sickness absence within 8 weeks after surgery increased with total load lifted per day from 15 to 53%. Longer sickness absence was associated with an increased HR of reoperation, but within strata of sickness absence, we found no increase in the HR of reoperation with increasing exposures. CONCLUSION: We did not find indications that the HR of reoperation was related to occupational mechanical exposures, even after accounting for a potential protective effect of sickness absence. Hence, the exposure-related prolonged duration of sickness absence could not be explained by exposure-related complications that led to reoperation.

Prenatal detection of chromosome aneuploidies by fluorescence in situ hybridization: experience with 2000 uncultured amniotic fluid samples in a prospective preclinical trial.

Successful rapid prenatal detection of selected numerical chromosome abnormalities by using fluorescence in situ hybridization (FISH) on uncultured amniotic fluid samples has been described by Klinger et al. (1992) and Ward et al. (1993, 1997). Using essentially the same FISH protocol and identical probes specific for chromosomes 21, 18, 13, X, and Y, we prospectively compared the results of FISH and conventional cytogenetics on 2000 amniotic fluid cell samples. The 1-day FISH assay yielded discrete differences in the signal profiles between cytogenetically disomic, i.e., normal, and trisomic samples. Due to intermittent absent Y-signals, the assay differentiated less well between samples with cytogenetically normal and abnormal sex chromosome complements. The assay efficiency, and thus the clinical utility, was affected by (1) unsuccessful hybridizations (7 per cent of all hybridizations), (2) hybridizations with less than 50 scorable nuclei (19 per cent of all hybridizations), and (3) visibly contaminated samples with possible maternal cell contamination (14 per cent of all samples). As a result, we were not able to reproduce the results of Klinger et al. (1992) and Ward et al. (1993, 1997).

Prenatal detection of chromosome aneuploidies in uncultured chorionic villus samples by FISH.

We developed a 1-d FISH assay for detection of numerical chromosome abnormalities in uncultured chorionic villus samples (CVS). Probes specific for chromosomes 13, 18, 21, X, and Y were used to determine ploidy by analysis of signal number in hybridized nuclei. Aneuploidy detection using this assay was directly compared with the results obtained by conventional cytogenetic analysis in a consecutive, clinical study of 2,709 CVS and placental samples. The FISH assay yielded discrete differences in the signal profiles between cytogenetically normal and abnormal samples. On the basis of these results, we generated FISH-assay cutoff values that discriminated between karyotypically normal and aneuploid samples. Samples with mosaicism and a single sample with possible heritable small chromosome X probe target were exceptions and showed poor agreement between FISH results and conventional cytogenetics. We conclude that the FISH assay may act as a more accurate and less labor-demanding alternative to "direct" CVS analysis.

Method validation in relation to accuracy and precision for the gas chromatography-mass spectrometric analysis of 19-nortestosterone in urine with heptafluorobutyric anhydride and N-methyl-N-(trimethylsilyl)trifluoroacetamide.

Method validation for all the analytical methods used in food control is of the highest priority. For this control there is a lack of reference materials, thus, it is necessary to validate the methods each time they are used for new applications. Among the many aspects of validation, this report pays particular attention to repeatability and reproducibility. The within-assay variability gives a good indication of the precision of the method shown by the repeatability. The between-assay variability gives no indication on the accuracy (or trueness) because no certified reference material is available. The reproducibility however, also gives an indication of the precision of the method. In this work the limit of detection, also an aspect of validation, was found to be below 0.375 micrograms 1-1 for both derivatization methods; however, the precision of the heptafluorobutyric anhydride method was found to be better than that of the N-methyl-N-(trimethylsilyl)trifluoroacetamide method.