Reduction of intussusception: defining a better index of successful non-operative treatment.

The reported non-operative reduction rate for intussusception is usually the proportion of attempted non-operative (radiological) reductions that succeed, which we term the "selective reduction rate." This value shows wide variation that may result from selection bias that is difficult to quantify because data regarding primary operative treatment are frequently lacking. The proportion of patients with late clinical presentation or pathological lead points can also distort the apparent efficacy of non-operative treatment. We found no definitions of outcome measures in the literature or practice guidelines to inform analysis. Based on analysis of our own audit data we derived a "composite reduction rate" from first principles that can account for variations in radiological and surgical treatment thresholds that might bias other measures of successful non-operative treatment. This index is the proportion of intussusceptions not requiring resection that are successfully reduced non-operatively. We propose that the composite reduction rate be used as a key component of standardised multidisciplinary outcome reporting for intussusception rather than the selective reduction rate. The reduced bias and confounding would allow fairer comparisons and lead to better outcome standards.