Computer-derived equations for predicting survival postoperatively. Their usefulness and limitations

We used multivariate analysis to determine whether survival following perforations of the gastrointestinal tract could be accurately predicted from preoperative data. Of 12 variables tested, four were found to have predictive value. These were age, pulmonary disease, preoperative shock, and the attending surgeon. When these four variables were employed in a logistic regression equation on 42 patients, it correctly predicted which 21 patients died before leaving the hospital. To produce an equation useful for other hospitals, we recalculated it without the attending surgeon variable. Again, the equation was used to predict survival. The correlation of predicted vs observed outcome remained high, and, using a 2 x 2 chi 2 test, the correlation was significant. We then cross validated the three-variable model on data from a second hospital. The model accurately predicted the new data equally well. We believe that predictive models can identify risk factors in a variety of patient populations and can determine who is likely to benefit from specific treatment modalities.     

Calciphylaxis – a topical overview

'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis.     

The Sigma-trial protocol: a prospective double-blind multi-centre comparison of laparoscopic versus open elective sigmoid resection in patients with symptomatic diverticulitis

Backround  

Diverticulosis is a common disease in the western society with an incidence of 33–66%. 10–25% of these patients will develop diverticulitis. In order to prevent a high-risk acute operation it is advised to perform elective sigmoid resection after two episodes of diverticulitis in the elderly patient or after one episode in the younger (< 50 years) patient. Open sigmoid resection is still the gold standard, but laparoscopic colon resections seem to have certain advantages over open procedures. On the other hand, a double blind investigation has never been performed. The Sigma-trial is designed to evaluate the presumed advantages of laparoscopic over open sigmoid resections in patients with symptomatic diverticulitis.