Performing spinal anesthesia using a conventional approach can be considerably challenging in obese patients. Multiple needle attempts may lead to a higher incidence of complications (e.g., postdural puncture headache, paresthesia, hematoma, and infection) and increase patient discomfort and dissatisfaction. Therefore, novel techniques are needed to improve the success rate of spinal anesthesia for such patients.~There are two puncture approaches for spinal anesthesia: median approach puncture and paramedian approach puncture. Early studies have noted that the success rate of paramedian approach puncture was higher than that of median approach puncture and that it is associated with fewer complications and postoperative complications.~A paramedian approach has been shown to improve the success rate of spinal anesthesia, especially in patients who are unable to sit up or those with a degenerative spine condition. The use of ultrasound has been suggested to increase the efficacy of spinal anesthesia.~Recently, ultrasound has emerged as a way to facilitate lumbar neuraxial blocks, namely, the ultrasound assistance (USAS) technique. The ultrasound assistance technique is beneficial for lumbar neuraxial anesthesia, improving technique performance by providing reliable anatomical information.
The aim of this study is to compare the paramedian approach for spinal anesthesia using ultrasound assistance (USAS) versus conventional palpation in morbidly obese patients undergoing elective surgeries.