The efficacy and prognosis analysis of short-term spinal cord stimulation in the treatment of zoster-associated pain: a retrospective study

Abstract

Background: Zoster-associated pain (ZAP) is the most common and intractable complication in the clinical setting when patients with herpes zoster (HZ) seek medical treatment. Short-term spinal cord stimulation (stSCS) has been validated as an effective means to relieve ZAP. However, in the existing literature, there is a paucity of comprehensive reports elaborating on the risk factors that impact its treatment efficacy.

Objective: This study aimed to evaluate the clinical efficacy of stSCS in the treatment of ZAP, and to analyze the risk factors that influence the treatment efficacy.

Methods: Clinical data of patients diagnosed with ZAP and who underwent stSCS surgery in the Pain Department of Shanxi Bethune Hospital from January 2020 to December 2023 were collected. A retrospective analysis was performed to evaluate their clinical efficacy. Principal component analysis (PCA) was utilized to screen potential factors influencing the efficacy, and Logistic regression was employed to establish a predictive model. The accuracy of the model was assessed through the Receiver Operating Characteristic (ROC) curve and the C-index.

Results: A total of 98 patients were enrolled in this study. After stSCS treatment, the visual analogue scale (VAS) scores of pain were significantly reduced, the sleep quality of patients was improved, and the dosage of analgesic drugs was markedly decreased compared with that before treatment. The results of multivariate Logistic regression analysis indicated that age [odds ratio (OR): 1.175; 95% confidence interval (CI): 1.864-2.584; p = 0.021], disease course (OR:1.894; 95% CI: 1.563-2.365; p = 0.003), diabetes mellitus (OR: 2.805; 95% CI: 2.425-3.539; p = 0.025), and the pain area size (OR: 3.208; 95% CI: 1.705-2.213; p = 0.001) were independent risk factors affecting the efficacy of stSCS in the treatment of ZAP.

Conclusion: Our findings suggest that, stSCS effectively relieves ZAP patients' pain, reduces analgesics consumption, improves sleep quality, with low complication rate and high safety. Notably, age, disease course, diabetes mellitus, and pain area size are independent risk factors for its efficacy. The C-index and ROC area, both 0.824, show the prediction model has good accuracy and discriminative power.

Keywords: clinical efficacy; herpes zoster; postherpetic neuralgia; risk factors; short-term spinal cord stimulation; zoster-associated pain.

Figure 1

Experimental design and methodology flowchart. ZAP, zoster-associated pain; stSCS, short-term spinal cord stimulation; VAS, visual analogue scale; PSQI, Pittsburgh sleep quality index.

Figure 2

Herpes zoster in different distribution areas. (A) herpes zoster in the distribution area of cervical nerves; (B) herpes zoster in the distribution area of thoracic nerves; (C) herpes zoster in the lumbosacral nerve distribution area.

Figure 3

The anteroposterior X-ray film shows that the electrode is located in the target area outside the spinous process and inside the pedicle of vertebral arch. (A) neck; (B) chest; (C) lumbar.

Figure 4

The lateral X-ray film shows that the electrode is located in the posterior epidural space. (A) neck; (B) chest; (C) lumbar.

Figure 5

(A) Comparison of VAS; (B) Comparison of PSQI. Compared to before treatment, *p < 0.05. VAS, visual analogue scale; PSQI, Pittsburgh sleep quality index.

Figure 6

Mean consumption of pregabalin (A) and gabapentin (B). Compared to before treatment. *p < 0.05.

Figure 7

Principal component analysis and determination of the number of variables. (A) Scree plot, starting from the fifth principal component, the eigenvalue of the principal component begins to decline slowly, indicating that the first five principal components can explain most of the variance of the data. The contribution of subsequent principal components to the variance gradually decreases. We select principal components with eigenvalues greater than 1. (B) Proportion of variance lot, when the cumulative contribution rate of the principal components that can be explained reaches 75%, we select the first five principal components.

Figure 8

ROC curve of the poor prognosis prediction model for ZAP patients after stSCS. AUC is area under the curve. The closer it is to 1, the higher the prediction accuracy of the model. ZAP, zoster-associated pain; stSCS, short-term spinal cord stimulation.