Regional anesthesia techniques have become fundamental in modern anesthetic practice, offering superior intraoperative conditions, extended postoperative analgesia, and improved patient recovery compared to general anesthesia [1]. Among these, the supraclavicular brachial plexus block is often referred to as the “spinal of the upper limb,” as it provides dense anesthesia and excellent postoperative pain control for surgeries below the mid-humerus level [2]. The introduction of ultrasound guidance has significantly enhanced the precision, onset, and safety of this block by enabling real-time visualization of neural structures, needle advancement, and local anesthetic spread [3,4]. Traditionally, bupivacaine has been the mainstay long-acting local anesthetic for peripheral nerve blocks. However, its potential cardiotoxic and neurotoxic effects have encouraged the adoption of safer stereoisomers such as levobupivacaine and ropivacaine, both pure S-enantiomers developed to retain efficacy while reducing systemic toxicity [1,2]. Levobupivacaine, the S-isomer of bupivacaine, provides prolonged sensory and motor blockade with a lower incidence of cardiac and central nervous system side effects, whereas ropivacaine exhibits a favorable safety profile and a degree of sensory–motor differentiation, facilitating earlier postoperative recovery [3,5]. Although both agents have demonstrated excellent clinical performance, published studies have reported heterogeneous findings regarding their onset, duration, and analgesic quality when used for ultrasound-guided supraclavicular brachial plexus block [1–4]. Variations in methodology, drug concentration, and block techniques may contribute to this inconsistency. Hence, a systematic and standardized comparison is warranted. The present study was therefore designed to compare 0.5% levobupivacaine and 0.5% ropivacaine for ultrasound-guided supraclavicular brachial plexus block in patients undergoing upper-limb surgeries. The objectives were to evaluate and compare the onset and duration of sensory and motor blockade, postoperative analgesic efficacy, hemodynamic stability, and safety profile of both agents, thereby identifying the anesthetic that provides optimal block characteristics with maximal safety and patient comfort.

Study Design and Setting: A prospective, randomized comparative study was conducted in the Department of Anaesthesiology, Navodaya Medical College and Hospital, Raichur, from January 2025 to May 2025. The study was carried out after obtaining approval from the Institutional Ethics Committee and written informed consent from all participants. Study Population: Fifty adult patients of both gender, aged 18–60 years, belonging to ASA physical status I and II, scheduled for elective upper-limb surgeries under supraclavicular brachial plexus block, were included. Inclusion Criteria: Adult patients aged 18–60 years. ASA physical status I or II. Patients undergoing elective orthopedic or soft-tissue procedures of the upper limb. Willingness to provide informed consent. Exclusion Criteria: Patient refusal for regional anesthesia. Local infection at the injection site. Known hypersensitivity to amide local anesthetics. Coagulopathy or anticoagulant therapy. Pre-existing peripheral neuropathy or neuromuscular disorders. Severe cardiopulmonary, renal, or hepatic disease. Sample Size and Grouping: A total of 50 patients were randomly allocated into two equal groups of 25 each using a computer-generated randomization table: Group L (Levobupivacaine Group): Received 25 mL of 0.5% levobupivacaine. Group R (Ropivacaine Group): Received 25 mL of 0.5% ropivacaine. Procedure: All patients were premedicated with midazolam 1 mg IV and standard monitors (ECG, NIBP, SpO₂) were applied. The block was performed under strict aseptic precautions with the patient in the supine position and head turned to the opposite side. Using a high-frequency linear ultrasound transducer (6–13 MHz), the brachial plexus was visualized at the supraclavicular level. A 22-gauge insulated nerve block needle was advanced under real-time ultrasound guidance, and after negative aspiration, the assigned study drug was injected in 5-mL increments around the plexus sheath to ensure uniform spread. Assessment Parameters: Onset of sensory block: Time from drug injection to loss of pinprick sensation in all dermatomes. Onset of motor block: Time from injection to inability to flex or extend the wrist and fingers. Duration of sensory block: Time from onset to the return of dull pain sensation. Duration of motor block: Time from onset to complete recovery of motor power. Time to first rescue analgesia: Interval between completion of block and first request for analgesic (VAS ≥ 4). Hemodynamic parameters: Heart rate, systolic and diastolic blood pressure, and oxygen saturation were recorded at baseline and every 10 min intraoperatively. Adverse effects: Incidence of vascular puncture, local anesthetic systemic toxicity (LAST), Horner’s syndrome, or neurological deficits were noted. Postoperative Analgesia: Rescue analgesia was provided with intravenous diclofenac 75 mg when VAS ≥ 4. Total analgesic consumption in the first 24 hours was recorded. Statistical Analysis: Data were analyzed using SPSS version 25.0 (IBM Corp, USA). Continuous variables were expressed as mean ± standard deviation (SD) and analyzed using the unpaired Student’s t-test. Categorical variables were compared using the Chi-square test or Fisher’s exact test as appropriate. A p-value < 0.05 was considered statistically significant.

A total of 50 patients undergoing elective upper-limb surgeries under ultrasound-guided supraclavicular brachial plexus block were analyzed, with 25 patients each in the Levobupivacaine group (Group L) and Ropivacaine group (Group R). Both groups were comparable in baseline demographic and clinical characteristics, including age, sex distribution, body mass index (BMI), ASA physical status, and mean duration of surgery (p > 0.05), as shown in Table 1. This indicates adequate randomization and homogeneity between the groups prior to intervention. Table 1. Baseline Demographic and Clinical Characteristics Parameter Levobupivacaine (n = 25) Ropivacaine (n = 25) p-value Age (years, mean ± SD) 39.8 ± 12.1 40.6 ± 11.7 0.79 Male/Female (n) 16 / 9 15 / 10 0.78 BMI (kg/m², mean ± SD) 24.6 ± 3.2 24.9 ± 3.5 0.74 ASA I / II (n) 14 / 11 13 / 12 0.79 Duration of surgery (min, mean ± SD) 72 ± 18 74 ± 20 0.63 The onset of sensory and motor block was similar in both groups, showing no statistically significant difference (p = 0.58 and p = 0.71, respectively). However, the duration of sensory block and motor block were significantly longer with levobupivacaine (640 ± 92 min and 520 ± 84 min, respectively) compared with ropivacaine (560 ± 88 min and 465 ± 80 min, respectively) (p = 0.001 and p = 0.009). Similarly, the time to first rescue analgesic requirement was markedly prolonged in the levobupivacaine group (610 ± 95 min) compared with the ropivacaine group (535 ± 90 min), demonstrating a statistically significant difference (p = 0.003) as depicted in Table 2. Table 2. Onset and Duration of Sensory and Motor Block Variable Levobupivacaine (n = 25) Ropivacaine (n = 25) p-value Onset of sensory block (min, mean ± SD) 8.4 ± 1.6 8.1 ± 1.8 0.58 Onset of motor block (min, mean ± SD) 12.3 ± 2.1 12.6 ± 2.3 0.71 Duration of sensory block (min, mean ± SD) 640 ± 92 560 ± 88 0.001* Duration of motor block (min, mean ± SD) 520 ± 84 465 ± 80 0.009* Time to first rescue analgesia (min, mean ± SD) 610 ± 95 535 ± 90 0.003* *Statistically significant (p < 0.05) Intraoperative hemodynamic parameters such as mean arterial pressure (MAP) and heart rate (HR) remained stable and comparable between both groups throughout the perioperative period (p > 0.05). However, the requirement for intraoperative rescue boluses was significantly lower in the levobupivacaine group (4%) compared to the ropivacaine group (20%) (p = 0.046). Postoperative opioid consumption within 24 hours was also lower among patients receiving levobupivacaine (median 5 mg [IQR: 0–10]) versus those receiving ropivacaine (median 10 mg [IQR: 5–15]) (p = 0.021). Additionally, patient satisfaction scores were higher in the levobupivacaine group (9.0 ± 0.8) compared to the ropivacaine group (8.5 ± 1.0), with a statistically significant difference (p = 0.049) as detailed in Table 3. Table 3. Intraoperative and Postoperative Parameters Parameter Levobupivacaine Ropivacaine p-value Mean arterial pressure (mmHg, mean ± SD) 83.2 ± 7.1 84.6 ± 6.9 0.47 Heart rate (beats/min, mean ± SD) 78.4 ± 6.8 79.2 ± 7.0 0.62 Intraoperative rescue bolus required (n / %) 1 (4.0%) 5 (20.0%) 0.046* 24-h opioid equivalent (mg, median [IQR]) 5 [0–10] 10 [5–15] 0.021* Patient satisfaction score (0–10, mean ± SD) 9.0 ± 0.8 8.5 ± 1.0 0.049* Regarding safety and block success, all patients in both groups achieved successful surgical anesthesia without the need for conversion to general anesthesia (100% success rate). Minor complications were rare and comparable between the groups. One case of vascular puncture occurred in each group, while transient Horner’s syndrome was observed in one patient receiving levobupivacaine. No incidence of local anesthetic systemic toxicity (LAST) or neurological deficit was reported during the 24-hour postoperative follow-up period. These observations are summarized in Table 4. Table 4. Adverse Events and Block Success Outcome Levobupivacaine (n = 25) Ropivacaine (n = 25) p-value Successful surgical anesthesia (n / %) 25 (100%) 25 (100%) – Vascular puncture (n / %) 1 (4.0%) 1 (4.0%) 1.00 Transient Horner’s syndrome (n / %) 1 (4.0%) 0 (0%) 0.31 Local anesthetic systemic toxicity 0 0 – Neurological deficit at 24 h 0 0 –

The present prospective, randomized comparative study evaluated the clinical efficacy and safety of 0.5% levobupivacaine versus 0.5% ropivacaine in ultrasound-guided supraclavicular brachial plexus block for upper-limb surgeries. Both agents provided satisfactory anesthesia and effective postoperative analgesia with stable hemodynamics. However, levobupivacaine demonstrated a significantly longer duration of sensory and motor block and prolonged analgesia compared to ropivacaine, without increasing adverse effects. In the current study, the onset times for sensory and motor blockade were comparable in both groups (p > 0.05), consistent with prior findings by Malav et al. (2018), who reported similar onset characteristics between levobupivacaine and ropivacaine in sciatic nerve blocks [7]. The comparable onset can be attributed to their similar pKa and lipid solubility, which determine diffusion kinetics across the neural membrane. Li et al. (2017) also demonstrated in a meta-analysis of randomized controlled trials that both agents exhibit equivalent onset profiles in various peripheral nerve blocks [8]. The duration of sensory and motor blockade in our study was significantly longer with levobupivacaine (640 ± 92 min and 520 ± 84 min, respectively) compared with ropivacaine (560 ± 88 min and 465 ± 80 min, respectively). These findings mirror those of González-Suárez et al. (2009) and Casati et al. (2002), who observed that levobupivacaine produces denser and more prolonged blockade due to its greater lipid solubility and higher protein-binding affinity [9,10]. The time to first rescue analgesia was also markedly prolonged in the levobupivacaine group (p = 0.003), suggesting superior postoperative analgesic efficacy. This observation aligns with the conclusions of Kirksey et al. (2015), who reviewed local anesthetic adjuvants and emphasized that levobupivacaine provides prolonged sensory block duration even without adjuvant supplementation [6]. Both local anesthetics maintained hemodynamic stability throughout the perioperative period, and no major complications such as pneumothorax, systemic toxicity, or prolonged neurological deficits were reported. This finding agrees with Ghali (2012), who compared the two agents in peribulbar anesthesia and found both to be equally safe, with minimal cardiovascular or central nervous system toxicity [11]. Minor adverse events like vascular puncture and transient Horner’s syndrome in our study were self-limiting and did not necessitate intervention, reflecting the inherent safety of these S-enantiomeric amide agents. The postoperative analgesic requirement was lower among patients receiving levobupivacaine, corroborating earlier evidence that it provides longer-lasting analgesia than ropivacaine. Studies by Casati et al. (2002) and Malav et al. (2018) similarly noted extended sensory block and delayed analgesic demand with levobupivacaine [7,10]. Although ropivacaine offers the advantage of earlier motor recovery potentially useful in ambulatory surgeries levobupivacaine remains superior for procedures necessitating sustained analgesia and immobility. The 100% success rate in achieving surgical anesthesia with ultrasound guidance underscores its pivotal role in improving block precision. The use of ultrasound facilitates real-time visualization of nerve structures, ensuring optimal spread of local anesthetic and minimizing complications such as pneumothorax or vascular puncture. Li et al. (2017) emphasized that ultrasound-guided approaches consistently enhance block efficacy and safety compared to landmark-based techniques [8]. Overall, the findings of our study are consistent with earlier evidence that levobupivacaine provides a more durable and reliable block profile, whereas ropivacaine offers similar safety with slightly shorter duration [6–11]. The choice between the two should thus be guided by surgical duration and postoperative analgesic needs. Although unrelated to local anesthesia, the advanced detection methodologies described by Meng et al. (2020) highlight how precision tools—like ultrasound in anesthesiology—are reshaping procedural accuracy in modern medical practice [12].

The present study demonstrated that both levobupivacaine (0.5%) and ropivacaine (0.5%) are effective and safe local anesthetics for ultrasound-guided supraclavicular brachial plexus block in upper-limb surgeries. Both agents provided stable hemodynamics, high block success rates, and minimal adverse effects. However, levobupivacaine produced a significantly longer duration of sensory and motor blockade, prolonged postoperative analgesia, and greater patient satisfaction compared to ropivacaine. The onset times were comparable in both groups. Hence, levobupivacaine offers a distinct advantage where extended analgesia is desired, without compromising safety. It may therefore be considered a superior alternative to ropivacaine for prolonged upper-limb surgical procedures under regional anesthesia.

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