DISCUSSION
HZ‐related pain, postherpetic neuralgia, pain
POSTHERPETIC NEURALGIA
This is the first prospective study on two distinct needle tip positions in PRF for HZ‐related pain. In this study, it was shown that the patients in the IP group had significantly better pain relief and higher activities of daily living than that in the OP group.There is controversy in the treatment of HZ‐related pain with PRF. A systematic review in 2019 concluded that the evidence for most interventional procedures used to treat postherpetic neuralgia is Level 2, according to “The Oxford Levels of Evidence 2”.The mechanism of PRF for pain relief is unknown. Chen et al.Clinically, although PRF can effectively relieve HZ‐related pain, there are still some patients with poor pain relief and the factors that influence the efficacy of PRF treatment are uncertain. At present, studies have found that needle tip position may affect the treatment efficacy. Irwin et al.There were some limitations in the study. First, the main limitation of our study was that the sample size was small and the follow‐up period was short, which may affect the reliability of this study. Second, morphine equivalent consumption may not be quantified. We could not standardize pain therapies after discharge, resulting in a potential bias of follow‐up results. Third, the pathologic anatomy of the DRG may differ in the spine. Radiologically, there were three types of the location of the DRG (intraspinal, foraminal, and extraforaminal). In this study, we only considered foraminal and extraforaminal DRG because previous research found that the intraspinal types only occurred at the L5 level in the lumbar spine, and the incidence of the variation was 5.7%.In conclusion, the position of the needle tip had an influence on the PRF treatment in patients with HZ‐related pain. Positioning the needle tip in the area between the medial and lateral edges of adjacent pedicles offered good HZ‐related pain relief and improved quality of life.