Transversus abdominis plane block and quadratus lumborum block did not reduce the incidence or severity of chronic postsurgical pain following cesarean section: a prospective, observational study

Background
Sparse data exist on the prevalence and severity of chronic postsurgical pain (CPSP) following cesarean section. Our study aimed to compare the effectiveness of transversus abdominis plane (TAP) block and quadratus lumborum block (QLB) in the prevention of CPSP after cesarean section.

Methods
The study was conducted at a tertiary hospital from June 2017 to July 2018 as a prospective, observational trial. We recruited 233 women with singleton pregnancies, above 18 years of age, ≥ 36 weeks of gestation, undergoing cesarean section under spinal anesthesia. The patients received either TAP block or QLB as the primary analgesia technique following cesarean section. The control group consisted of patients without any postsurgical plane block. The incidence and characteristics of chronic pain were evaluated using the Neuropathic Pain Symptom Inventory at the first, third, and sixth months after surgery.

Results
Fewer patients in the control group perceived CPSP than in TAP or QLB groups one and three months after cesarean section, but not after six months. Accordingly, CPSP severity was significantly lower in the control group than after plane blocks at the first and third month. No difference in the risk of CPSP was found between different indications for cesarean delivery.

Conclusions
CPSP is highly prevalent following cesarean section. The studied plane blocks did not reduce the incidence or severity of CPSP after cesarean section when compared to the standard analgesic regimen.