Spinal cord stimulation in patients with diabetic foot: Determining prognosis using infrared thermography

We aimed to determine whether perioperative infrared thermography (IRT) could be used as an index of success in the treatment of spinal cord stimulation (SCS) in patients with diabetic foot (DF) and in selecting suitable candidates for long-term SCS.

Thirty-three DF patients who met the inclusion criteria underwent permanent SCS implantation at Shengjing Hospital from January 2021 to August 2023. Patients were grouped by preoperative Wagner grading, and peripheral sensory neuropathy was tested with a 10-g monofilament. Preoperative and 1-week postoperative IRT was performed to record lower limb skin temperature. Patients were divided into success (no amputation) and failure (amputation) groups based on limb salvage status. Receiver operating characteristic curve and logistic regression analysis were used for evaluation.

All patients completed 6-month follow-up with pain relief (preoperative VAS: 6.82 ± 1.32; postoperative VAS: 5.48 ± 1.18; P < 0.001), and 52 limbs were salvaged (success rate: 78.8 %). No significant difference in success rate was found among different Wagner grades (P = 0.293). The success group had increased postoperative IRT (△IRT: 0.65 °C), while the failure group had decreased IRT (△IRT: 0.70 °C). The success rate was lower in patients with large-fiber neuropathy (59.1 % vs 88.6 %, P = 0.007). The diagnostic threshold of △IRT was -0.12 °C (AUC = 0.79, P < 0.001). Logistic regression showed large-fiber neuropathy (P = 0.025) and △IRT (P = 0.001) were related to prognosis.

SCS treatment effectively relieved lower limb pain. Patients with DF and large-fiber neuropathy had a lower surgical success rate. IRT was significantly higher in the treatment success group. Perioperative IRT changes of < -0.12 °C and combined large-fiber neuropathy were identified as warning signs, and patients with these signs should be treated with caution when receiving long-term SCS therapy. IRT can be used as a diagnostic index for the prognosis of patients with DF receiving SCS and to select suitable long-term SCS treatment candidates.