RESUMEN
BACKGROUND AND OBJECTIVES: Paresthesiae occasionally occur during spinal puncture or injection of local anesthetic for spinal anesthesia. No information is currently available regarding the effects of the patient's position on the incidence of needle-induced paresthesiae. The purpose of this prospective, observational study was to compare the occurrence of needle-induced paresthesiae in patients who received single-shot spinal anesthesia in the sitting position or in the lateral decubitus position. METHODS: A total of 620 patients operated on under spinal anesthesia were included. Spinal anesthesia was performed in the sitting position in 142 patients and in the lateral decubitus position in 478 patients. All blocks were performed with a 25-gauge, 90-mm, Sprotte needle, at the L3-L4 or L4-L5 level. Patients' demographics, patients' position (lateral decubitus or sitting), number of skin punctures, incidence of paresthesiae, and success of the anesthesia were recorded. RESULTS: The overall incidence of paresthesiae was higher in the lateral decubitus position (16.95%) compared with the sitting position (9.15%) (P = 0.0230). The number of punctures and the success rate were similar in both positions. Studying the incidence of paresthesiae for each position, when performing 1 or more punctures, there was no position-related difference noted if a single-needle puncture was sufficient to perform the block (8.0% in the lateral decubitus group versus 5.1% in the sitting group) (P = 0.3305). This difference between positions was significant when more than a single-needle puncture was required (34.1% in the lateral decubitus group versus 18.6% in the sitting group) (P = 0.0497). CONCLUSIONS: Patient's position may influence the occurrence of needle-induced paresthesiae during spinal anesthesia. Lateral decubitus position resulted in a higher incidence of paresthesiae than the sitting position. However, there is no position-related difference noted if a single-needle puncture is sufficient to perform the block.