Background: Chronic postsurgical pain (CPSP) is common and would reduce the quality of life of patients. Transversus abdominal plane (TAP) block has been widely used in lower abdominal surgery and many researchers demonstrated that it could improve acute postsurgical pain. We aim to determine whether TAP block could improve chronic postoperative pain at 3 months and 6 months after colorectal surgery.
Methods: A total of 307 patients received selective colorectal surgery under general anesthesia between January, 2015 and January, 2019 in a single university hospital were included: 128 patients received TAP block combined with patient-controlled intravenous analgesia (PCIA) for postsurgical analgesia (group TP) and 179 only administrated with PCIA (group P). Main outcome was the incidence of pain at 3 months and 6 months after colorectal surgery, and NRS score of pain at 24 hours, 48 hours, 3 months and 6 months after colorectal surgery. The data was analyzed by two-way repeated measures anova and the chi-square test.
Results: The NRS score decreased significantly at 24 hours after surgery (rest NRS 1.07±1.34 vs 1.65±1.67, P=0.003; and movement NRS 3.00±1.45 vs 3.65±1.89; p=0.003) and at 3 months after surgery (movement NRS 0.59±1.23 vs 0.92±1.65, p=0.045 )in group TP than that in group P. There were no significant difference of NRS score at 48 hours and 6 months after surgery (all p>0.05).
Among 307 patients, 62/307(20.2%) developed chronic post-surgical pain (CPSP) at 3 months after surgery, and 42/307(13.7%) experienced CPSP at 6 months after surgery. The prevalence of CPSP in group TP showed no significant difference compared with group P at 3 months (19.5% vs 20.7%, p=0.806) and 6 months (13.2% vs 13.9%, p=0.863) after surgery.
Conclusions: TAP block could decrease the movement pain score at 3 months after surgery, but could not reduce the incidence of CPSP at 3 months and 6 months after selective colorectal surgery. TAP block may have positive effect on chronic postsurgical pain.