Results

The Consolidated Standards of Reporting Trials (CONSORT) flow diagram of the study is shown in Figure 1.

Figure 1: CONSORT flow diagram of the study.CONSORT flow diagram of the study showing that there was no loss to follow-up and that a total of 45 patients in each group were analyzed.CONSORT, Consolidated Standards of Reporting Trials

The baseline demographic and clinical characteristics of the study population are presented in Table 1.

Characteristic | Group L (N = 45) | Group R (N = 44) | Total
Gender | Male | 25 (55.6%) | 17 (38.6%) | 42 (47.2%)
Female | 20 (44.4%) | 27 (61.4%) | 47 (52.8%)
ASA | I | 29 (64.4%) | 21 (47.7%) | 50 (56.2%)
II | 16 (35.6%) | 23 (52.3%) | 39 (43.8%)
Age group | 18-20 years | 4 (8.9%) | 3 (6.8%) | 7 (7.9%)
21-30 years | 8 (17.8%) | 6 (13.6%) | 14 (15.7%)
31-40 years | 9 (20%) | 9 (20.5%) | 18 (20.2%)
41-50 years | 15 (33.3%) | 15 (34.1%) | 30 (33.7%)
51-60 years | 9 (20%) | 11 (25%) | 20 (22.5%)

Table 2 compares the sex distribution, age group distribution, ASA physical status, and body weight between the two groups. The majority of patients in both groups were female. There was no statistically significant difference in sex distribution between the two groups (p > 0.05). Patients were categorized into five age groups (18-20, 21-30, 31-40, 41-50, and 51-60 years). The distribution of patients across the age groups was comparable between the two groups, with no statistically significant difference (p > 0.05). The study population comprised adults aged 18-60 years. The majority of patients were classified as ASA physical status I, followed by ASA physical status II. The distribution of ASA physical status was comparable between the two groups, with no statistically significant difference (p > 0.05). The mean body weight was also comparable between Group L and Group R, with no statistically significant difference (p > 0.05).

Characteristic | Group L (N = 45), n (%) | Group R (N = 44), n (%) | p-value
Gender | Male | 25 (55.6) | 17 (38.6) | 0.14# (χ² = 2.55)
Female | 20 (44.4) | 27 (61.4)
ASA | I | 29 (64.4) | 21 (47.7) | 0.14# (χ² = 2.55)
II | 16 (35.6) | 23 (52.3)
Age group | 18-20 years | 4 (8.9) | 3 (6.8) | 0.961# (χ² = 0.617)
21-30 years | 8 (17.8) | 6 (13.6)
31-40 years | 9 (20.0) | 9 (20.5)
41-50 years | 15 (33.3) | 15 (34.1)
51-60 years | 9 (20.0) | 11 (25.0)

The primary outcome measures are presented in Table 3. The mean onset of sensory block was significantly faster in Group L (5.98 ± 1.39 minutes) than in Group R (8.31 ± 1.01 minutes). The difference between the two groups was highly statistically significant (p < 0.001), indicating earlier establishment of sensory blockade with intrathecal levobupivacaine. Group L also demonstrated a significantly faster onset of motor block (8.68 ± 1.81 minutes) than Group R (11.76 ± 1.42 minutes). The difference was highly statistically significant (p < 0.001), suggesting a more rapid onset of motor blockade with levobupivacaine. The mean duration of sensory block was significantly longer in Group L (268.11 ± 42.90 minutes) than in Group R (160.48 ± 51.74 minutes). The difference was highly statistically significant (p < 0.001), demonstrating prolonged sensory anesthesia with levobupivacaine. Similarly, the mean duration of motor block was significantly longer in Group L (230.89 ± 48.42 minutes) than in Group R (136.02 ± 41.62 minutes). The difference was highly statistically significant (p < 0.001), indicating prolonged motor blockade with levobupivacaine. The duration of postoperative analgesia was also significantly longer in Group L (275.22 ± 39.54 minutes) than in Group R (207.66 ± 39.34 minutes). The difference was highly statistically significant (p < 0.001), reflecting superior and prolonged postoperative analgesia with levobupivacaine.

Outcome measure | Group L (N = 45), mean ± SD | Group R (N = 44), mean ± SD | t-value | p-value
Onset of sensory blockade (minutes) | 5.98 ± 1.39 | 8.31 ± 1.01 | 9.01 | <0.001*
Onset of motor blockade (minutes) | 8.68 ± 1.81 | 11.76 ± 1.42 | 8.92 | <0.001*
Duration of sensory blockade (minutes) | 268.11 ± 42.90 | 160.48 ± 51.74 | 10.34 | <0.001*
Duration of motor blockade (minutes) | 230.89 ± 48.42 | 136.02 ± 41.62 | 9.9 | <0.001*
Duration of analgesia (minutes) | 275.22 ± 39.54 | 207.66 ± 39.34 | 8.08 | <0.001*

Comparisons of systolic blood pressure, diastolic blood pressure, MAP, and heart rate between the two groups are shown in Figure 2 and Figure 3.

Figure 2: Comparison of SBP, DBP, and MAP between the two groups.DBP, diastolic blood pressure; LDBP, left diastolic blood pressure; LMAP, left mean arterial pressure; LSBP, left systolic blood pressure; MAP, mean arterial pressure; RDBP, right diastolic blood pressure; RMAP, right mean arterial pressure; RSBP, right systolic blood pressure; SBP, systolic blood pressure

Figure 3: Comparison of heart rate between Groups L and R.

Systolic blood pressure remained comparable between the two groups throughout the intraoperative and postoperative periods. Repeated-measures ANOVA with Greenhouse-Geisser correction demonstrated a significant effect of time on systolic blood pressure (F = 8.065, p < 0.001), indicating expected perioperative changes over time. However, there was no significant overall group effect (F = 0.295, p = 0.588) or time × group interaction (F = 1.052, p = 0.393), suggesting that both levobupivacaine and ropivacaine maintained comparable systolic blood pressure profiles during the study period.

Diastolic blood pressure remained comparable between the two groups throughout the intraoperative and postoperative periods. Repeated-measures ANOVA with Greenhouse-Geisser correction demonstrated a significant effect of time on diastolic blood pressure (F = 21.363, p < 0.001), indicating expected perioperative changes over time. However, there was no significant overall group effect (F = 0.140, p = 0.709) or time × group interaction (F = 1.075, p = 0.379), suggesting that both levobupivacaine and ropivacaine maintained comparable diastolic blood pressure profiles during the study period.

MAP remained stable and comparable between the two groups throughout the intraoperative and postoperative periods. Repeated-measures ANOVA with Greenhouse-Geisser correction demonstrated a significant effect of time on MAP (F = 21.847, p < 0.001), indicating expected perioperative changes over time. However, there was no significant overall group effect (F = 0.240, p = 0.626) or time × group interaction (F = 1.063, p = 0.385), suggesting that both levobupivacaine and ropivacaine maintained comparable MAP profiles during the study period.

Heart rate remained comparable between the two groups throughout the intraoperative and postoperative periods. Repeated-measures ANOVA with Greenhouse-Geisser correction demonstrated a significant effect of time on heart rate (F = 29.209, p < 0.001), indicating expected perioperative changes over time. However, there was no significant overall group effect (F = 1.379, p = 0.244) or time × group interaction (F = 0.562, p = 0.705), suggesting that both levobupivacaine and ropivacaine maintained comparable heart rate profiles during the study period.

The comparison of VAS scores is presented in Table 4. The VAS was assessed at 30-minute intervals using a 0-10 scale. Postoperative VAS scores were consistently lower in Group L than in Group R during the early postoperative period, indicating superior analgesia with levobupivacaine. The intergroup difference at the 12-hour postoperative time point was statistically significant (p = 0.017).

Time point | Group L (N = 45), mean ± SD | Group R (N = 44), mean ± SD | z-value | p-value
Four hours | 0.49 ± 0.506 | 0.61 ± 0.579 | 0.942 | 0.346#
Six hours | 1.13 ± 0.661 | 1.18 ± 0.691 | 0.093 | 0.926#
12 hours | 0.42 ± 0.499 | 0.70 ± 0.553 | 2.38 | 0.017*
24 hours | 0.11 ± 0.318 | 0.14 ± 0.347 | 0.36 | 0.719#

The comparison of postoperative rescue analgesic requirements between the two groups is presented in Table 5 and Figure 4. Although patients in Group L required fewer postoperative rescue analgesic doses than those in Group R, the difference was not statistically significant, either in the distribution of rescue analgesic doses (chi-square test, p = 0.292) or in the mean number of rescue analgesic doses (p = 0.075).

Number of rescue analgesic doses | Group L (N = 45), n (%) | Group R (N = 44), n (%) | p-value
None | 21 (46.7) | 17 (38.6) | 0.292# (χ² = 4.95)
One dose | 17 (37.8) | 14 (31.8)
Two doses | 7 (15.6) | 9 (20.5)
Three doses | 0 (0.0) | 2 (4.5)
Four doses | 0 (0.0) | 2 (4.5)
Mean ± SD | 0.69 ± 0.73 | 1.05 ± 1.10 | 0.075† (t = 1.8)

Figure 4: Comparison of postoperative rescue analgesic dose requirements between Groups L and R.