Efficacy Analysis of Temporary Spinal Cord Stimulation in the Treatment of Refractory Postherpetic Neuralgia.

Background: Spinal cord stimulation can be considered in PHN patients if conservative treatment is not effective. However, the long-term pain outcomes of temporary (7-14 days) spinal cord stimulation (tSCS) in refractory PHN patients with a course of more than 3 months have not been  documented.

Objectives: To investigate the efficacy of tSCS as a treatment for refractory PHN.

Study design: Retrospective study.

Setting: Pain Department in a university hospital.

Methods: A total of 52 patients with refractory PHN were treated with tSCS between March 2018 and February 2021. Their medical records were collected, and the patients were divided into 3 groups according to the course of their disease into the medium-term group, long-term group and ultra-long-term group. The changes in the numeric rating scale (NRS) scores, Pittsburgh sleep quality index (PSQI) responses, pain relief rate, postoperative efficiency and patients' use of analgesics were recorded before the operation, 3 days, 10 days, one month, 3 months, 6 months and 12 months after the operation.

Results: The average NRS scores, the maximum NRS scores and the PSQI scores at 3 days, 10 days, one month, 3 months, 6 months and 12 months after the operation were significantly lower than those before the operation (P < 0.05). The average NRS scores and the maximum NRS scores of all groups increased significantly from one month to 6 months compared to those at 10 days after the tSCS treatment, and they decreased significantly at 12 months compared with 6 months post-operation. The average NRS scores of the medium-term and long-term group were significantly lower than that of the ultra-long-term group at 1-3 months after the operation, and the maximum NRS scores at one month, 3 months and 12 months after the operation were also significantly lower in the medium-term and long-term group compared to the ultra-long-term group. The average PSQI scores at 1-12 months after the operation were not significantly higher than that at 10 days after the operation, but it decreased significantly at 12 months compared with 6 months after the operation. Among the 3 groups, the PSQI scores of the medium-term and long-term group were significantly lower than those of the ultra-long-term group at 6 months after the operation. The postoperative pain relief rate ranged from 41.51%-59.81%, and the total effective rate was 42.31%-69.23%, and there was no significant difference among the 3 groups. Some patients still needed analgesics at 12 months after the operation, but the number of patients who were taking medications post-operation was significantly lower than that before the operation.

Limitations: This is a single-center retrospective study with the inability to completely control for variables. Additionally, the number of cases is small and the follow-up duration is short.

Conclusion: tSCS can be used as a safe and effective method to relieve refractory PHN, and the curative effect is substantially higher in patients with a disease course of 3-12 months compared to that in patients with a course of more than 12 months.