Modified subcutaneous lumbar spine index (MSLSI): a new predictor for early surgical site infection after transforaminal lumbar interbody fusion.

PURPOSE: The purpose of this study is to explore the value of Modified subcutaneous lumbar spine index (MSLSI) as a new predictor for early surgical site infection (SSI) after transforaminal lumbar interbody fusion (TLIF).

METHODS

We conducted a retrospective case-control study involving patients who underwent TLIF between 2015 and 2021 at our hospital. Thirty-one patients with early postoperative SSI were enrolled in cases group, and the controls were matched (1:2) using the following criteria: gender (female/male), age (±3 y), diabetes (insulin/oral/no), date of surgery (morning/afternoon) and season of surgery (spring/summer/autumn/winter). MSLSI was measured on mid-sagittal T2-weighted MRI imaging. Pearson correlation analysis was calculated to evaluate the relationship between MSLSI and BMI. The Receiver Operating Characteristic (ROC) curve was performed to evaluate the value of MSLSI and subcutaneous fat thickness in predicting the early SSI following TLIF. The radiographic parameters were measured independently by two doctors using the Picture Archiving Communication System (PACS).

RESULTS

Ninety-three patients were enrolled in final analysis, with 31 cases in SSI group and 62 matched controls. Univariate and multivariate logistic regression analysis indicated that SSI were significantly correlated with obesity (OR = 6.43, 95%CI = 1.16-35.73, p = 0.033), subcutaneous fat thickness (OR = 4.53, 95%CI =1.32-15.52, p = 0.016) and MSLSI (OR = 6.17, 95%CI = 1.73-22.12, p = 0.005). The ROC curve demonstrated that the risk of early SSI development increased when the MSLSI was ≥0.68. Pearson correlation analysis indicated that MSLSI was moderate correlation with body mass index (BMI).

CONCLUSION

MSLSI represents an innovative radiographic index that independently predicts early SSI risk after TLIF.