INTRODUCTION Lower segment Caesarean Section (LSCS) is one of the most common surgical procedures which offers a safe delivery option for mothers and infants in various obstetric scenarios. Spinal Anaesthesia is often used for both elective as well as emergency Caesarean Section. It is a neuraxial technique where local anaesthetic is injected directly into the subarachnoid space that houses CSF. Lignocaine 5% (heavy) was the drug used for spinal anaesthesia because of its short duration of action, intense blockade and quick recovery. But it has been associated with Transient Neurological symptoms (Pain originating in the gluteal region and radiating to both the lower extremities). Nowadays 0.5% Hyperbaric Bupivacaine is extensively used for spinal anaesthesia. It causes less incidence of TNS, prolonged duration of sensory block but its disadvantage is of prolonged motor blockade. Levobupivacaine and Ropivacaine, both members of the amino amide class of local anaesthetics offer lower cardiovascular and central nervous system toxicity while maintaining effective spinal anaesthesia. Levobupivacaine, a pure S(-) enantiomer of Bupivacaine has greater lipid solubility and protein binding, resulting in a denser and long-lasting sensory and motor block. Ropivacaine is less lipophilic and exhibits greater sensory-motor differentiation, producing a shorter duration of motor blockade with relatively preserved sensory anaesthesia. Although several studies have evaluated these agents individually or compared them with Bupivacaine, direct comparative evidence evaluating the spinal block characteristics of Hyperbaric 0.75% Ropivacaine and Hyperbaric 0.5% Levobupivacaine in parturients undergoing LSCS is limited. Therefore, the present study was undertaken to compare the onset and duration of sensory and motor blockade following intrathecal administration of Hyperbaric 0.75% Ropivacaine and Hyperbaric 0.5% Levobupivacaine in patients undergoing Lower Segment Caesarean Section

This prospective, randomized comparative study was conducted in the Department of Anaesthesiology at a tertiary care teaching hospital over an 18-month period after obtaining approval from the Institutional Ethics Committee and written informed consent from all participants. The sample size was calculated based on the primary outcome measure (onset of sensory blockade) using data from a previously published study.10 Assuming a two-sided α error of 0.05, a study power of 80%, an expected mean difference of 0.80 minutes, and a pooled standard deviation of 1.66, the minimum required sample size was estimated to be 68 patients per group, yielding a total sample size of 136 participants. A total of 136 ASA physical status II parturients aged 18–40 years with singleton term pregnancy (≥37 weeks) undergoing lower segment caesarean section were enrolled and randomly allocated into two equal groups- Group R and Group L (n = 68 each). Women with multiple gestations or contraindications to spinal anaesthesia, including infection at the puncture site or coagulopathy, were excluded from the study. Group R received 2 mL of intrathecal Hyperbaric 0.75% Ropivacaine, whereas Group L received 2 mL of intrathecal Hyperbaric 0.5% Levobupivacaine. Spinal anaesthesia was administered at the L3–L4 interspace using a 25-gauge Quincke spinal needle under strict aseptic precautions. Sensory blockade was assessed systematically using loss of pinprick sensation until the T6 dermatome was achieved, following which sensory regression was assessed periodically until complete recovery. Motor blockade was evaluated using the Modified Bromage Scale.13 The primary outcome measures were the onset and duration of sensory blockade and the onset and duration of complete motor blockade. Standard intraoperative monitoring was performed in all patients. STATISTICAL ANALYSIS Data were entered into Microsoft Excel and analyzed using IBM SPSS Statistics software (IBM Corp., Armonk, NY, USA). Onset and duration of sensory and motor blockade were expressed as mean ± standard deviation (SD), whereas categorical variables were presented as frequencies and percentages. Intergroup comparisons of continuous variables, including the onset and duration of sensory and motor blockade, were performed using the independent Student's t-test. Categorical variables were compared using the Chi-square test or Fisher's exact test, as appropriate. All statistical tests were two-tailed, and a P value of <0.05 was considered statistically significant.

A total of 136 parturients were enrolled and randomized equally into Group R (hyperbaric 0.75% Ropivacaine, n = 68) and Group L (hyperbaric 0.5% Levobupivacaine, n = 68). Both groups were comparable with respect to baseline demographic and obstetric characteristics, with no statistically significant intergroup differences. DEMOGRAPHIC PROFILE Age Distribution Table 1: Age Distribution of Study Participants Age Group (Years) Group R (n=68) No. (%) Group L (n=68) No. (%) Total (N=136) No. (%) 18–22 12 (17.6%) 9 (13.2%) 21 (15.4%) 23–27 27 (39.7%) 32 (47.1%) 59 (43.4%) 28–32 24 (35.3%) 19 (27.9%) 43 (31.6%) 33–37 5 (7.4%) 8 (11.8%) 13 (9.6%) Mean ± SD 26.84 ± 4.09 yrs 26.75 ± 4.06 yrs 26.80 ± 4.07 yrs p-value (t-test) 0.900 (NS) — — The majority of patients in both groups belonged to the age group of 23–27 years: 27 (39.7%) in Group R and 32 (47.1%) in Group L, followed by the 28–32 year bracket [Group R: 24 (35.3%), Group L: 19 (27.9%)]. The mean age was comparable between the two groups — 26.84 ± 4.09 years in Group R and 26.75 ± 4.06 years in Group L (p = 0.900, NS), confirming homogeneity of the study population with respect to age. Gestational Age Distribution Table 2: Gestational Age Distribution Gestational Age Group R (n=68) No. (%) Group L (n=68) No. (%) Total (N=136) No. (%) 37 weeks 12 (17.6%) 20 (29.4%) 32 (23.5%) 38 weeks 24 (35.3%) 16 (23.5%) 40 (29.4%) 39 weeks 19 (27.9%) 15 (22.1%) 34 (25.0%) 40 weeks 13 (19.1%) 17 (25.0%) 30 (22.1%) Mean GA ± SD 38.49 ± 0.99 wks 38.43 ± 1.15 wks 38.46 ± 1.07 wks p-value (t-test) 0.752 (NS) — — All patients were at term (≥37 weeks gestation) as per inclusion criteria. In Group R, the highest proportion of patients were at 38 weeks gestation [24 (35.3%)], while in Group L, the majority were at 37 weeks [20 (29.4%)]. The mean gestational age was 38.49 ± 0.99 weeks in Group R and 38.43 ± 1.15 weeks in Group L, with no statistically significant difference (p = 0.752, NS), indicating comparability of foetal maturity across the two groups. CHARACTERISTICS OF SPINAL BLOCK Table 4: Characteristics of Spinal Block – Group R vs Group L Parameter Group R (n=68) Mean ± SD Group L (n=68) Mean ± SD p-value Onset of Sensory Block (min) 5.33 ± 1.52 4.16 ± 1.29 <0.001* Duration of Sensory Block (min) 109.99 ± 15.08 133.96 ± 17.68 <0.001* Onset of Motor Block (min) 6.76 ± 1.48 5.78 ± 1.31 <0.001* Duration of Motor Block (min) 96.76 ± 15.03 113.49 ± 14.42 <0.001* * Statistically significant (p < 0.001), unpaired t-test. Highly significant differences were observed between the two groups for all block parameters (p< 0.001 for all). Levobupivacaine (Group L) demonstrated a faster onset of sensory block (4.16 ± 1.29 min) compared to Ropivacaine (Group R: 5.33 ± 1.52 min). The duration of sensory block was markedly prolonged in Group L (133.96 ± 17.68 min) compared to Group R (109.99 ± 15.08 min), indicating superior duration of action of Levobupivacaine. Similarly, onset of motor block was faster in Group L (5.78 ± 1.31 min vs 6.76 ± 1.48 min) and duration of motor block was longer (113.49 ± 14.42 min vs 96.76 ± 15.03 min). These differences are clinically relevant for procedural planning and postoperative analgesia.

This prospective, randomized, comparative study evaluated the spinal block characteristics of intrathecal hyperbaric 0.75% Ropivacaine versus hyperbaric 0.5% Levobupivacaine for spinal anaesthesia in patients undergoing Lower Segment Caesarean Section. A total of 136 patients (68 per group) were enrolled and followed through the perioperative period. The key findings are discussed below in context with existing literature. The demographic parameters including age, weight, height, and gestational age were comparable between the two groups with no statistically significant differences (all p > 0.05), confirming adequate randomization. The mean age of patients in Group R was 26.89 ± 4.06 years compared to 26.77 ± 4.03 years in Group L. These findings are consistent with the study by Adapa et al. (2022)10, who reported similar baseline demographics in their comparative study of Levobupivacaine and Ropivacaine for spinal anaesthesia in LSCS, with mean ages of approximately 24–28 years. The homogeneity of demographic data in the present study ensures that differences observed in block characteristics are attributable to the pharmacological properties of the drugs rather than patient-related confounders. In the present study, the mean onset of sensory block to the T6 dermatome was significantly faster in Group L (4.16 ± 1.28 min) compared to Group R (5.33 ± 1.51 min) (p <0.001). The present findings are also supported by Edara et al.,14 which demonstrated a significantly faster onset of sensory blockade with Hyperbaric 0.5% Levobupivacaine than with Hyperbaric 0.75% Ropivacaine in patients undergoing PCNL surgery. The findings are also consistent with those reported by Athar et al.15 The faster onset observed with Levobupivacaine in our study may be related to its greater intrinsic potency and physicochemical properties, resulting in more rapid establishment of sensory blockade.5,6 The clinical significance lies in the faster surgical readiness in Group L, which could be advantageous in urgent LSCS cases. The duration of sensory block was significantly longer in Group L (133.96 ± 17.55 min) compared to Group R (109.99 ± 14.97 min) (p <0.001). The longer sensory block duration of Levobupivacaine is consistent with previous comparative studies of Levobupivacaine and Ropivacaine. A similar longer duration of sensory blockade with Levobupivacaine has been reported by Edara et al.14 and Athar et al.15 This may be attributed to higher protein binding and lipid solubility of Levobupivacaine.6 This translates into extended postoperative pain coverage, reducing early analgesic requirements and improving the perioperative patient experience. Onset of complete motor block (Bromage score 3) was significantly faster in Group L (5.78 ± 1.30 min) compared to Group R (6.76 ± 1.46 min) (p <0.001). The faster onset of motor block with Levobupivacaine is consistent with the greater motor blocking effect reported for the drug.6 Edara et al. also observed similar results.14 This provides a practical advantage in the operating room by allowing earlier commencement of surgery, though this must be balanced against the prolonged recovery of motor function postoperatively. The duration of motor block was significantly longer in Group L (113.49 ± 14.32 min) compared to Group R (96.76 ± 14.92 min) (p <0.001). Ropivacaine's well-documented differential sensorimotor block — producing effective sensory block with relatively less intense and shorter motor block — makes it particularly advantageous for obstetric anesthesia.5 This property is attributed to Ropivacaine's unique physicochemical profile: lower lipid solubility limits penetration of large-diameter myelinated Aα motor fibers, while allowing effective blockade of smaller Aδ and C sensory fibers. The shorter motor block duration observed with Ropivacaine in the present study supports early postoperative mobilization and faster return to activities of daily living, which is especially important for the postpartum mother. STRENGHTS OF THE STUDY The strengths of this study include its prospective randomized design and adequate sample size. A standardized spinal anaesthesia technique and uniform assessment of sensory and motor blockade were used for all participants, ensuring consistency in data collection. The study also provides direct comparison of hyperbaric 0.75% Ropivacaine and hyperbaric 0.5% Levobupivacaine in parturients undergoing lower segment caesarean section, adding useful evidence to the limited available literature. LIMITATIONS OF THE STUDY This study has a few limitations. First, it was conducted at a single tertiary care centre, so the findings may not be applicable to all hospitals or patient populations. Second, only ASA physical status II term parturients were included; therefore, the results cannot be directly applied to high-risk obstetric patients. Third, fixed doses of hyperbaric 0.75% Ropivacaine and hyperbaric 0.5% Levobupivacaine were used, and different doses were not evaluated. Finally, patient satisfaction and long-term postoperative outcomes were not assessed. Further multicentre studies with larger sample sizes are needed to confirm these findings.

CONCLUSION Intrathecal hyperbaric 0.5% Levobupivacaine demonstrated superior spinal block characteristics compared with hyperbaric 0.75% Ropivacaine in parturients undergoing lower segment caesarean section. Levobupivacaine produced a significantly faster onset and longer duration of both sensory and motor blockade, whereas Ropivacaine was associated with a shorter duration of motor blockade, which may facilitate earlier postoperative mobilisation. Both agents provided adequate surgical anaesthesia, and the choice between them may be guided by the desired balance between prolonged anaesthesia and early motor recovery.

1. Santos A, Pedersen H, Finster M, Edström H. Hyperbaric bupivacaine for spinal anesthesia in cesarean section. Anesth Analg. 1984;63:1009-13. 2. Cyna AM, Andrew M, Emmett RS, Middleton P, Simmons SW. Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev. 2006;(4):CD002251. 3. Hampl KF, Schneider MC, Ummenhofer W, Drewe J. Transient neurologic symptoms after spinal anesthesia. Anesth Analg. 1995;81:1148-53. 4. Bannister J, McClure JH, Wildsmith JAW. Effect of glucose concentration on the intrathecal spread of 0.5% bupivacaine. Br J Anaesth. 1990;64:232-4. 5. Kuthiala G, Chaudhary G. Ropivacaine: A review of its pharmacology and clinical use. Indian J Anaesth. 2011;55:104-10. 6. Foster RH, Markham A. Levobupivacaine: A review of its pharmacology and use as a local anaesthetic. Drugs. 2000;59:551-79. 7. Graf BM, Abraham I, Eberbach N, Kunst G, Stowe DF, Martin E. Differences in cardiotoxicity of bupivacaine and Ropivacaine are the result of physicochemical and stereoselective properties. Anesthesiology. 2002;96:1427-34. 8. McClure JH. Ropivacaine. Br J Anaesth. 1996;76:300-7. 9. McDonald SB, Liu SS, Kopacz DJ, Stephenson CA. Hyperbaric spinal Ropivacaine: A comparison to bupivacaine in volunteers. Anesthesiology. 1999;90:971-7. 10. Adapa S, Sai Somasundhaar S, Anbazhagan N. Comparative study of the efficacy of levobupivacaine and ropivacaine in spinal anaesthesia for lower segment caesarean section. J Cardiovasc Dis Res. 2022;13(8):1217-1231. 11. Oraon P, Bhagwan N, Damp D, Astha P, Naik N, Nirali N. Effectiveness of ropivacaine versus levobupivacaine for spinal anaesthesia and analgesia in lower limb surgery. Journal of Medical Science and Clinical Research. 2022;29(4):530-539. 12. Singh G, Rathod NM, Patel K. Comparison of equipotent doses of hyperbaric Ropivacaine and hyperbaric Levobupivacaine in spinal anaesthesia for patients undergoing lower abdominal and lower limb surgeries. Indian J Anesth Analg. 2019;6:249-54. 13. Bromage PR. Epidural Analgesia. Philadelphia: WB Saunders; 1978. 14. Edara S, Hymavathi VN, Reddy VVK, Kiran LV. Comparing 0.75% Ropivacaine vs 0.5% Levobupivacaine for spinal block in PCNL surgeries: A randomized study. Int J Curr Pharm Res. 2025;17(6):82-87. doi:10.22159/ijcpr.2025v17i6.7095. 15. Athar M, Ahmed SM, Ali S, Doley K, Varshney A, Siddiqi MohdMH. Levobupivacaine or ropivacaine: A randomised double blind controlled trial using equipotent doses in spinal anaesthesia. Colomb J Anesthesiol. 2016 Apr;44(2):97–104.