Gupta VP, Zhou Y, Manson JF, et al. - A multicenter retrospective case-control study was performed to evaluate the relationship between the spine adipose index and deep surgical site infection and determine a threshold value for spine adipose index that can assist in preoperative risk stratification in patients undergoing posterior instrumented lumbar fusion (PILF). Patients who had undergone PILF from January 1, 2010, to December 31, 2018, were examined. Researchers included 42 patients in the final analysis, with twenty-one cases and twenty-one matched controls. The relationship between SAI and the development of deep surgical site infection (SSI) was applied using Stepwise binary logistic regression analysis. They used separate logistic regression models for body mass index (BMI) and direct measures of subcutaneous fat thickness. They applied Receiver Operating Characteristic analysis to ascertain the optimal value for SAI, and subsequent risk ratios were estimated applying the identified threshold. Intra- and inter-observer reliabilities were assessed using intra-class coefficients. The results demonstrate that in patients undergoing PILF surgery, the spine adipose index is a novel radiographic measure and an independent risk factor for developing deep SSI, with 0.51 being the ideal threshold value for pre-operative risk stratification.