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.

NCT Number	NCT07549776
Lead Sponsor	Instituto Nacional Materno Perinatal, Peru
Conditions	Obesity, Cesarean Section
Enrollment	100 participants
Start Date	2025-07-01
Primary Completion	2026-01-01 (estimated)
Study Completion	2026-01-01 (estimated)
Updated on ClinicalTrials.gov	2026-07-07