Complications of Percutaneous Nephrolithotomy and their Management

Introduction: Increasing global prevalence of nephrolithiasis has resulted in the development of new minimally invasive techniques and has also led to the resurgence of established methods such as percutaneous nephrolithotomy (PCNL). This procedure is now recommended as the first option for the treatment of single large or multiple renal stones and those in the inferior calyx. This study was done to assess the complications of PCNL and their management, in our centre. Methods: Medical records of 144 patients who underwent PCNL at Lumbini Medical College Teaching Hospital, during the last one year were reviewed. The demographic data, size, tract number and location of the calculi, and intraoperative and postoperative complications were evaluated. The various parameters of the calculi were evaluated. Descriptive analysis with frequencies was done. Results: Complications occurred in 13 (9.02%) patients. Post operative bleeding occurred in seven (4.8%) patients, out of which one patient developed pseudoaneurysms and the other developed arteriovenous fistula. One patient developed hypovolemic shock immediately after surgery. Frequent blockage of urine, excessive drainage of urine from the drain site, hemothorax and colonic perforation was seen in one  patient each. One patient had mortality due to post operative bleeding. Complications increased with the number and size of stones and number and site of the tracts. Conclusion: Percutaneous nephrolithotomy has low complication rate in experienced hands and complications depend upon stone size, history of open stone surgery, tract number, and tract location

Modeling of longitudinal polytomous outcome from complex survey data - application to investigate an association between mental distress and non-malignant respiratory diseases

<p>Abstract</p> <p>Background</p> <p>The data from longitudinal complex surveys based on multi-stage sampling designs contain cross-sectional dependencies among units due to clustered nature of the data and within-subject dependencies due to repeated measurements. Special statistical methods are required to analyze longitudinal complex survey data.</p> <p>Methods</p> <p>Statistics Canada's longitudinal National Population Health Survey (NPHS) dataset from the first five cycles (1994/1995 to 2002/2003) was used to investigate the effects of demographic, social, life-style, and health-related factors on the longitudinal changes of mental distress scores among the NPHS participants who self-reported physician diagnosed respiratory diseases, specifically asthma and chronic bronchitis. The NPHS longitudinal sample includes 17,276 persons of all ages. In this report, participants 15 years and older (n = 14,713) were considered for statistical analysis. Mental distress, an ordinal outcome variable (categories: no/low, moderate, and high) was examined. Ordered logistic regression models based on the weighted generalized estimating equations approach were fitted to investigate the association between respiratory diseases and mental distress adjusting for other covariates of interest. Variance estimates of regression coefficients were computed by using bootstrap methods. The final model was used to predict the probabilities of prevalence of no/low, moderate or high mental distress scores.</p> <p>Results</p> <p>Accounting for design effects does not vary the significance of the coefficients of the model. Participants suffering with chronic bronchitis were significantly at a higher risk (OR_adj= 1.37; 95% CI: 1.12-1.66) of reporting high levels of mental distress compared to those who did not self-report chronic bronchitis. There was no significant association between asthma and mental distress. There was a significant interaction between sex and self-perceived general health status indicating a dose-response relationship. Among females, the risk of mental distress increases with increasing deteriorating (from excellent to very poor) self-perceived general health.</p> <p>Conclusions</p> <p>A positive association was observed between the physician diagnosed self-reported chronic bronchitis and an increased prevalence of mental distress when adjusted for important covariates. Variance estimates of regression coefficients obtained from the sandwich estimator (i.e. not accounting for design effects) were similar to bootstrap variance estimates (i.e. accounting for design effects). Even though these two sets of variance estimates are similar, it is more appropriate to use bootstrap variance estimates.</p