Spinal Anesthesia Performed Under Previous Ultrasound Examination Guidance. Report of 30 Cases Scheduled for Orthopedic Surgery

Abstract

Introduction: During the last ten years, ultrasound (US) guidance has revolutionized regional anesthesia field in many countries. Despite this, its role in central neuroaxial blockade has been underappreciated by anesthesiologists. Ultrasound examination is useful to identify and mark intervertebral levels, needle insertion point for a midline approach and also to estimate needle orientation and depth from skin surface to subarachnoid space. This is especially helpful in difficult cases. In addition, ultrasound identification of the intervertebral levels is more accurate than clinical estimation using the intercristal line. It also increases the success rate of dural puncture on the first needle insertion attempt. In this article, we share our experience in 30 consecutive central neuroaxial blockades guided by previous ultrasound examination. Methods: Thirty consecutive patients scheduled for orthopedic surgery under spinal anesthesia were included in this prospective analysis. Patients were placed in a sitting position. Ultrasound examination for skin markings and measurements was performed. After this was completed, anesthesia residents performed spinal anesthesia following those marks. Data required for analysis was recorded by an independent observer. Results: Mean time of ultrasound examination before spinal block performing was 5.6 minutes. Success rate of dural puncture on the first needle insertion attempt was 75%. In the rest 25%, the median number of needle passes required for success was 1 (1-3). It is important to state that 10% of the patients had previous spine surgery, 10% presented scoliosis with a severe deformity and 20% had BMI of 32 or more. Conclusion: Ultrasound-guided neuraxial blockade is a useful technique, especially for difficult patients. It is associated with a high success rate of dural puncture on the first needle insertion attempt and a reduction in the median number of needle passes required for success, even when spinal anesthesia was performed by in-training physicians.