Effect Of Paravertebral Nerve Block On Chronic Pain After Thoracic Surgery

Background and ObjectiveThoracotomy is often associated with moderate to severe pain.In all procedures,thoracotomy may be the type of surgery that most requires postoperative analgesia.In patients with thoracic surgery,about 38% to 63% of patients have acute moderate to severe pain(NRS?3),of which about 40% of patients with acute thoracotomy pain develop chronic post-surgical pain(CPSP).Poor control of postoperative pain may delay postoperative recovery and increase the risk of atelectasis,lung infection,and chronic pain.Chronic pain is often difficult to treat effectively and is often permanent.Therefore,prevention of the occurrence of CPSP is crucial.Thoracic paravertebral block(TPVB)blocks spinal and sympathetic trunks in the paravertebral space,producing somatosensory and sympathetic blockade,and is effective for analgesic treatment of unilaterally derived chest and abdominal pain.Studies have shown that the analgesic effect of TPVB on patients undergoing thoracic surgery is at least comparable to that of thoracic epidural analgesia(TEA)with fewer side effects.However,little research has been done on the effects of preoperative thoracic paravertebral block on CPSP in thoracic surgery.Therefore,we designed this prospective study to observe the effect of preoperative ultrasound-guided thoracic paravertebral nerve block on chronic pain at 6 months after thoracic surgery.Materials and MethodsPatients who underwent unilateral thoracic surgery from May 2018 to October 2018 were collected and interviewed one day before surgery to determine whether they were included in the study according to the selection criteria and exclusion criteria.According to whether the patient underwent ultrasound-guided thoracic paravertebral nerve block,the patients were divided into thoracic paravertebral nerve block(TPVB group)and general anesthesia group(GEN group).The acute pain intensity at rest and at coughing were evaluated on the 1st,2nd,and 3rd day after surgery,the number of compressions of the postoperative analgesic pump,whether nausea or vomiting within 3 days after surgery and length of stay were recorded in detail.The incidence and intensity of CPSP were evaluated by telephone at 3 months and 6 months after surgery.Results1.Inclusion of patients: From May to October 2018,a total of 565 cases met the inclusion criteria.447 patients(TPVB group: 266 patients,GEN group: 181 patients)completed the 3-month follow-up,and 424 patients(TPVB group: 248 patients,GEN group: 176 patients)completed the 6-months follow-up.2.Comparison of postoperative acute pain: Group TPVB had significantly less acute pain compared with group GEN on the 1st,2nd,and 3rd postoperative days both at rest and at coughing(p<0.05).3.Comparison of postoperative chronic pain: At 3 months postoperatively,the incidence of chronic pain in the TPVB and GEN groups was 47%(125/266)and 63%(114/181),respectively,with statistical differences(p<0.05),and the pain intensity of patients with chronic pain was not statistically different between the two groups(p>0.05);at 6 months after surgery,there was no significant difference in the incidence of chronic pain and pain intensity between the two groups(p>0.05)Conclusion1.Preoperative ultrasound-guided single paravertebral nerve block can effectively reduce the intensity of acute pain within 3 days after thoracic surgery.2.Compared with general anesthesia alone,combined ultrasound-guided single paravertebral nerve block may reduce the incidence of chronic pain in patients 3 months after thoracic surgery,but it has no significant effect on the incidence and intensity of chronic pain 6 months after surgery.Due to the characteristics of observational studies,no definitive conclusions can be drawn.