Retrospective Outcome Evaluation of Cervical Nucleoplasty Using Digital Infrared Thermographic Imaging

Abstract

Objective: Percutaneous cervical nucleoplasty (PCN) is used to treat cervical disc herniation. Radiological imaging studies, including plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI), have been used to make early predictions of cervical spinal surgery outcomes. However, simple radiological studies do not provide sufficiently detailed information; moreover, CT and MRI are highly expensive. Herein, we aimed to elucidate the usefulness of digital infrared thermography imaging (DITI) as an outcome marker after cervical nucleoplasty by correlating the changes in thermal difference (ΔTD) with the changes in pain intensity after PCN expressed as visual analogue scale (ΔVAS) scores.

Methods: For this study, 255 patients treated with PCN at Thomas Hospital between March 2012 and August 2014 were included. For each patient, demographic and clinical data, including preoperative MRI results, ΔVAS, ΔTD at the disc level treated with PCN, subjective symptom improvement, procedure-related discomfort, overall satisfaction, and adverse effects, were collected and evaluated for up to 3 months retrospectively.

Results: Thermal difference (TD) and VAS scores improved after PCN (p<0.05), but ΔTD showed no significant correlation with ΔVAS. If the preoperative TD was larger, the postoperative VAS was worse and there was less pain relief (ΔVAS) after PCN (p<0.05). Only few adverse effects were noticeable after PCN.

Conclusion: In DITI, which was used to evaluate the outcomes after cervical nucleoplasty, the ΔTD did not seem to reflect the ΔVAS after PCN. However, preoperative DITI findings could be useful for predicting VAS reduction and clinical improvements after PCN.

Keywords: Ablation technique; Cervical vertebrae; Intervertebral disc; Neck pain; Thermography.

Fig. 1.

Thermographic images before (A) and after (B) cervical nucleoplasty. The figures shows the change in thermal difference (ΔTD). The arrow indicates the most painful area of the affected limb. The preoperative TD in panel A had decreased in panel B postoperatively.

Fig. 2.

Change in TD after PCN. PCN, percutaneous cervical nucleoplasty; TD, thermal difference between the painful area in dermatome and the symmetrical area on the opposite limb; POD1D, postoperative day 1. Data are expressed as mean±95% confidence interval.

Fig. 3.

Change in pain severity after PCN. PCN, percutaneous cervical nucleoplasty; TD, thermal difference between the painful area in the dermatome and the symmetrical area in the opposite limb; VAS, visual analogue scale (from 0 [no pain] to 10 [worst pain imaginable]); POD1D, postoperative day 1; POD1W, postoperative week 1; POD1M, postoperative month 1; POD3M, postoperative month 3. Data are expressed as mean± 95% confidence interval.

Fig. 4.

Outcomes of percutaneous cervical nucleoplasty according to the modified McNab classification at postoperative month 3. Data are expressed as number (%).

Fig. 5.

Scatter plot of ΔTD and ΔVAS. Pearson correlation coefficient (r)=0.027, p=0.540. PCN, percutaneous cervical nucleoplasty; TD, thermal difference between the painful area in the dermatome and the symmetrical area in the opposite limb; ΔTD, change in TD after PCN; VAS, visual analogue scale (from 0 [no pain] to 10 [worst pain imaginable]); ΔVAS, change in VAS after PCN on postoperative day 1.