7.1. Limitations
neuropathic pain, nerve block, pain
CHRONIC PAIN, INFILTRATION
Some limitations of this study need to be considered. First, the sample size of our study (a single-center investigation) is slightly small, which may have biased the research results. Second, there was no blank control group in our clinical study because our local ethics committee believes that it is immoral to use normal saline for PVB or wound infiltration. Third, we failed to assess the nature of the postoperative chronic pain, that is, whether it was purely nociceptive pain or neuropathic pain. Fourth, all subjects in this study were given a 15 ml anesthetic load dose when they received paravertebral nerve block, but there was no significant difference in BMI between the two groups, so the average local anesthetic dose received by patients did not differ between the groups. Fifth, the paravertebral nerve block and catheter placement were performed after surgery, primarily to match the timing of analgesia in the CWI group and to minimize bias between groups due to the different timing of analgesia. Sixth, we did not collect more information about the patients' environment and behavior, which may have influenced the development of chronic pain. As a result, intraoperative drug infusion into the paravertebral space was not considered. However, despite such flaws, this study may still provide new insights into pain management in patients undergoing thoracic surgery.