No sample size estimation methodology currently exists for the right-censored count data models. We expect less number of attempts in the ultrasound group a 20 % difference between the two groups which we feel is a minimum of a clinically-relevant effect. At the 0.05 level of significance with a power of 0.8, we will require a minimum of 20 patients per group,therefore we plan to recruit 40 patients in total. Patients who consent to receive spinal anesthesia (as opposed to some other anesthetic technique) and who meet the inclusion/exclusion criteria for the study (given below) will be randomized on day of surgery after obtaining informed consent to either ultrasound-guided or standard spinal anesthesia technique. A block randomization scheme with random block sizes ranging from 2-8 patients will be used. The outcomes will be recorded by a third party observer in the block room/operating room who might be a nurse or resident or clinical research fellow not directly involved with performing the block. The post procedure outcomes will also be recorded by a clinical research fellow or resident who was not directly involved with performing the block. The analysis will be conducted by a statistician who will be blinded.