Infrared thermography as adjunctive imaging in spine surgery: Evaluating thermal asymmetry for predicting symptomatic level and recovery

Abstract

BACKGROUND

Objective assessment of pain relief and adequacy of decompression following spine surgery remains challenging. Infrared thermography (IRT) offers a non-invasive, radiation-free modality to visualize physiological changes in regional blood flow and inflammation.

AIM

To evaluate diagnostic concurrence and postoperative normalization of IRT in patients undergoing spine surgery, and to identify clinical predictors of recovery in thermal patterns.

METHODS

This retrospective study included 35 adult patients who underwent lumbar decompression or fusion procedures for spinal pathologies such as degenerative conditions, deformity, tumors and adjacent segment disease. The pre-operative and post-operative IRT scans were analyzed to quantify the focal temperature asymmetry corresponding to the symptomatic spinal levels. Two blinded reviewers independently evaluated the concurrence and postoperative normalization of the values.

RESULTS

The mean age of the cohort was 66.3 ± 10.7 years (males: 63.6%). Multilevel disease was present in 63.6% of patients. While the preoperative thermographic concurrence with the symptomatic level was observed in 78.8% of patients, postoperative normalization was demonstrable in 63.6%. The normalization rates were the highest for transforaminal lumbar interbody fusion (80%) and decompression-only procedures (66.7%). Logistic regression analysis identified female sex, diagnosis of single-level spinal stenosis and transforaminal lumbar interbody fusion surgery as the positive predictors for post-operative normalization. In contrast, multilevel disease was recognized as a negative predictor. Model performance showed moderate discriminative accuracy (area under curve: 0.64, 95% confidence interval: 0.52-0.76).

CONCLUSION

IRT demonstrated correlation with symptomatic spinal levels preoperatively and showed moderate association with postoperative thermal normalization following spine surgery. These preliminary findings suggest that IRT may provide additional, non-invasive information to complement standard imaging in the assessment of neural decompression and recovery. Larger, prospective studies are warranted to confirm its clinical utility and define its role in routine postoperative monitoring.

Keywords: Infrared thermography; Spine surgery; Neural decompression; Thermal asymmetry; Fusion

Core Tip: Infrared thermography (IRT) provides a novel, non-invasive biomarker for assessing symptomatic spinal levels and recovery after surgery. In this retrospective study, IRT demonstrated strong preoperative concurrence with clinical localization and meaningful postoperative normalization, particularly following transforaminal lumbar interbody fusion and decompression procedures. Female sex, single-level stenosis, and transforaminal lumbar interbody fusion surgery predicted favorable normalization, while multilevel disease hindered recovery. These findings highlight IRT’s potential as an adjunctive imaging tool to objectively evaluate adequacy of decompression and neural recovery, addressing a critical gap in postoperative spine surgery assessment.