The purpose of this study is to evaluate the impact of lumbar ultrasound anatomic mapping using the Accuro device on the number of needle redirections, when performing spinal anesthesia in the lateral decubitus position on patients undergoing elective cesarean delivery.

Training in neuraxial placement most commonly occurs with patients in the sitting position, since it is easy to master. However lateral placement may be preferred in emergent situations and for patient comfort. In order to provide safe and effective anesthesia to parturients, providers must be competent with the technique in both sitting and lateral positions.

Ultrasound examination prior to spinal placement is a safe, non-invasive method of determining depth, midline, and interspinous location. Its use may decrease the number of needle insertions and needle passes in parturients in the sitting position, however little is known about the benefit of ultrasound use in the placement of lateral spinals.

The use of lumbar ultrasound with Accuro may improve success rates, safety, and the education of residents as they learn neuraxial placement in the lateral position. This will be the first study to examine the use of Accuro for lateral neuraxial placement.

The study investigators hypothesize that lumbar ultrasound with the handheld Accuro device by an experienced provider prior to spinal insertion will result in fewer needle redirections compared to palpation of landmarks when performed by anesthesia residents or fellows.

The two arms of the study are as follows:

Group 1: Control Group: sham pre-puncture ultrasound procedure with the handheld Accuro device turned off, followed by a sham marking on the participant's back using the Accuro locator marker attached to the device.

Group 2: Ultrasound Group: pre-puncture ultrasound with Accuro followed by marking placed at the L3-4 interspace in the midline using the attached Accuro locator marker.

All ultrasound exams will be performed by an unblinded physician study investigator.

All study participants will have a spinal anesthetic in lateral position performed by one of the residents or fellows participating in the study.

Inclusion Criteria:

• pregnant women
• 18 years or older
• singleton pregnancy
• at least 37 weeks gestational age
• American Society of Anesthesiologists (ASA) Classification II
• body mass index (BMI) <35 kg/m2
• plan for elective and scheduled cesarean section with spinal anesthesia

Exclusion Criteria:

• patient refusal of spinal anesthesia
• uncorrected coagulopathy
• infection at the skin site of spinal placement
• increased intracranial pressure
• untreated hemodynamic instability
• history of scoliosis or spine surgery
• BMI >/=35 kg/m2
• allergy to local anesthetic
• allergy to opioids

There is no current IPD sharing plan for this data.

The patient and observer who collects the outcome data will be blinded to group allocation. The anesthesiologist caring for the patient and the resident/fellow performing the spinal anesthetic will be unblinded.