T2 high-signal-intensity zone of the spinal cord dorsal horn in patients treated with spinal cord stimulation for herpes zoster-associated pain: a retrospective case–control study

Purpose In patients with herpes zoster-associated pain (ZAP), magnetic resonance imaging (MRI) has revealed T2 high-signal intensity zones (MRI T2 HIZ) in the dorsal horn of the spinal cord, associated with postherpetic neuralgia (PHN). We retrospectively analyzed the relationship between PHN and MRI T2 HIZ in patients with refractory ZAP in the subacute phase who underwent temporary spinal cord stimulation therapy (tSCS).
Methods This single-center, case–control study included patients who underwent tSCS for refractory ZAP between 2010 and 2018. MRIs were re-assessed for the presence of T2 HIZ in the dorsal horn of the spinal cord. Patients were divided into T2 HIZ( +) and T2 HIZ(−) groups. Patients with a numerical rating score (NRS) ≥ 3 at the last visit were defined as PHN. The NRS values and the incidence rate of PHN were compared between the two groups.
Results Of the 67 cases extracted, 38 were included in the analysis: 22 in T2 HIZ( +) group and 16 in T2 HIZ(−) group. No significant differences were observed in background factors between the two groups. However, the T2 HIZ( +) group had a significantly higher NRS at the final visit (T2 HIZ( +):3.8 ± 2.1, T2 HIZ(−):1.4 ± 1.5; P < 0.05) and had significantly more patients with PHN than the T2 HIZ(−) group (T2 HIZ( +) vs. T2 HIZ(−), 15/22 (68%) vs. 3/16 (19%); odds ratio = 8.67; 95% confidence interval, 1.7–63.3).
Conclusion T2HIZ is detected in more than half of refractory ZAP, and pain is more likely to remain after tSCS treatment in the T2HIZ( +) group.