Ultrasound-guided Versus Landmark-based Spinal Anesthesia in Obese Parturients Undergoing Cesarean Section

Spinal anesthesia is the most commonly used anesthetic technique for cesarean section. However, in obese parturients, identification of the optimal puncture site using anatomical landmark palpation can be challenging because of altered anatomy. Preprocedural ultrasound has been proposed as a tool to improve localization of the puncture site and facilitate neuraxial access. This is a prospective comparative study included 100 obese parturients undergoing cesarean section under spinal anesthesia. Participants were allocated to one of two comparison groups according to the puncture site localization technique: a preprocedural ultrasound group and an anatomical landmark palpation group. The primary outcome is the first-attempt success rate, defined as successful cerebrospinal fluid return after the first needle insertion without needle redirection or a new skin puncture. Secondary outcomes include the number of puncture attempts, needle redirections, need for rescue interventions, incidence of paresthesia and vascular puncture during the procedure, and procedural times.

Inclusion Criteria: * Age ≥ 18 years * Pregnant women undergoing cesarean section * Body mass index (BMI) ≥ 30 kg/m² at the time of cesarean section * Scheduled for cesarean section under spinal anesthesia Exclusion Criteria: * Congenital spinal deformities * History of spinal surgery * Coagulopathy * Infection at the puncture site * Allergy to local anesthetics * Emergency cesarean section (NICE category 1)