Introduction

Spinal anesthesia is the most frequently utilized regional anesthesia technique for surgeries involving the infraumbilical region. It is an economical, dependable, and safe method that provides both surgical anesthesia and prolonged postoperative pain relief [1]. By enabling a more rapid onset and effective sensory and motor blockade, spinal anesthesia reduces intraoperative pain as well as endocrine, motor, and autonomic responses. Spinal anesthesia is favored because it is easier to administer, requires less time to perform, and has a higher success rate than other regional blocks using either blind or ultrasound-guided techniques. Although bupivacaine is the most commonly used local anesthetic for this purpose, it has the disadvantage of cardiotoxicity because of the R isomer [2]. Two newer amide local anesthetics, ropivacaine and levobupivacaine, are currently used to reduce the toxicity associated with bupivacaine because of their lower cardiotoxicity and neurotoxicity [2,3]. Levobupivacaine, the pure S(−) enantiomer of bupivacaine, is a safer choice for regional anesthesia than the racemic mixture. Owing to its favorable pharmacologic profile, levobupivacaine has been shown to be as effective as bupivacaine in clinical anesthetic practice in recent years.

Levobupivacaine has been shown to be clinically effective for regional anesthesia following both single-dose epidural administration and continuous postoperative epidural infusion. The incidence of adverse drug reactions is minimal when administered within the recommended dosage range [4]. Ropivacaine, the pure S(−) enantiomer of a long-acting amide local anesthetic, has a structure similar to that of bupivacaine. It is safer than racemic bupivacaine because of its lower potential for cardiotoxicity and neurotoxicity [5]. When regional anesthetic techniques require large volumes of local anesthetic infiltration, ropivacaine offers a clear advantage over bupivacaine because of its lower potential for toxicity.

Compared with intrathecal bupivacaine, intrathecal ropivacaine produces less intense motor block while providing a comparable duration of sensory block because it blocks Aδ and C nerve fibers more intensely than motor fibers (Aβ fibers). The ideal spinal anesthetic agent for ambulatory surgery should provide rapid onset of reliable surgical anesthesia of adequate duration, prompt recovery of sensory and motor function, and minimal complications. Thus, ropivacaine may be well suited for this purpose [5,6]. Therefore, this study was planned to compare the efficacy of intrathecal isobaric 0.75% ropivacaine and isobaric 0.5% levobupivacaine in elective lower abdominal and lower limb surgeries. The primary objective of the present study was to determine the onset and duration of sensory and motor blockade with each drug, and the secondary objective was to compare the Visual Analog Scale (VAS) score and the need for rescue analgesia between the two groups. We aimed to use the findings of this study to help establish a standard of care at our hospital for selecting the optimal anesthetic agent with a lower toxicity profile for infraumbilical surgeries.

This work was previously presented as a paper at the 2020 Indian Society of Anaesthesiologists (ISA) Puducherry State Conference, held on August 6, 2020.