European Journal of Cardiovascular Medicine

Effective postoperative pain management is a cornerstone of enhanced recovery after surgery (ERAS) protocols, particularly following major orthopedic procedures involving the lower limbs. Inadequately managed postoperative pain has been associated with delayed mobilization, prolonged hospitalization, increased morbidity, and diminished patient satisfaction [1–3]. Moreover, severe pain may impair respiratory mechanics, especially in elderly or high-risk patients, by limiting deep breathing and coughing—thus predisposing them to complications such as atelectasis and pneumonia [4,5]. Regional anesthesia techniques like epidural and paravertebral blocks are increasingly employed not only to provide effective analgesia but also to reduce systemic opioid requirements and their associated respiratory depressant effects [6–8].

The epidural block has long been considered the gold standard for lower limb surgeries due to its efficacy in producing dense bilateral analgesia and its versatility across procedures. However, it is often associated with hypotension, urinary retention, and limited early ambulation due to bilateral sympathetic blockade [9,10]. These adverse effects may hinder postoperative pulmonary recovery, especially in geriatric and comorbid populations [11].

The paravertebral block (PVB), by contrast, produces unilateral segmental somatic and sympathetic blockade and has shown promising results in terms of hemodynamic stability and safety, while providing effective pain relief [12,13]. Several studies in thoracic and abdominal surgeries have highlighted the advantages of PVB in minimizing opioid use and maintaining respiratory function [14,15]. Yet, its utility in lower limb surgeries, especially in the context of respiratory-relevant postoperative outcomes, remains underexplored.

This prospective comparative study was undertaken to evaluate and compare the efficacy of paravertebral and lumbar epidural blocks in postoperative analgesia following lower limb surgeries. In addition to pain scores and hemodynamic parameters, the study also explored secondary factors with indirect respiratory implications, including opioid-related side effects, early ambulation potential, and overall patient comfort—each of which contributes meaningfully to postoperative respiratory health.

Study Design and Setting

This randomized controlled comparative study was conducted at Gandhi Memorial and Associated Hospitals, King George’s Medical University, Lucknow, from August 2015 to August 2016. After obtaining institutional ethical clearance and informed written consent, 50 patients undergoing elective lower limb surgeries under regional anaesthesia were enrolled.

Inclusion and Exclusion Criteria

Inclusion criteria:

• Age 18–70 years
• ASA physical status I or II
• Scheduled for elective lower limb surgery under regional anaesthesia.

Exclusion criteria:

• Patient refusal
• Known allergy to study drugs
• Bleeding disorders
• Local infection at the site of block
• Hepatic or renal dysfunction
• Pregnancy or lactation

Randomization and Group Allocation

Patients were randomly divided into two groups (n=25 each):

Group E (Epidural group): Received lumbar epidural catheter placement (L2–L3 or L3–L4) with 10 ml of 0.5% ropivacaine + 1 µg/kg fentanyl bolus after 2 hours of spinal anaesthesia, followed by 5 ml 0.5% ropivacaine + 50 µg fentanyl every 3 hours for 24 hours.

Group P (Paravertebral group): Received catheter placement 2 cm lateral to L3 or L4 spinous process into the paravertebral space using an 18G Tuohy needle and similar drug regimen.

Procedure

All patients underwent subarachnoid block at L3–L4 using 15 mg bupivacaine heavy + 25 µg fentanyl. After 2 hours, the assigned block was activated. Standard monitors (NIBP, ECG, SpO₂) were attached and Ringer lactate 10–15 ml/kg was used for preloading.

In Group E, epidural catheterization was performed via midline/paramedian approach using the saline loss-of-resistance technique. In Group P, the catheter was inserted into the paravertebral space by identifying the transverse process, re-angling, and advancing 1–1.5 cm beyond bone contact. In both groups, a test dose of 3 ml lignocaine with adrenaline (1:200,000) was administered.

Postoperative Analgesia and Monitoring

Following catheter placement, a bolus dose of 0.5% ropivacaine with fentanyl was administered over 20 minutes. Subsequently, patients received intermittent doses every 3 hours for 24 hours. Analgesic adequacy and systemic effects were monitored via:

Pain assessment: Visual Analogue Scale (VAS, 0–10) at 0, 1, 3, 6, 9, 12, 15, 18, 21, and 24 hours.

Hemodynamic monitoring: HR, SBP, DBP, MAP.

Oxygen saturation (SpO₂): Measured continuously to assess indirect respiratory outcomes.

Rescue bolus: 5 ml of 0.5% ropivacaine was administered if VAS >4.

Rescue Interventions

Bradycardia: Atropine 0.5 mg IV if HR <50/min or >20% fall from baseline.

Hypotension: Mephentermine 6 mg IV for SBP <90 mmHg or >20% fall from baseline.

Assessment of Complications and Respiratory-Relevant Outcomes

The following were recorded to monitor potential opioid-related and block-related effects with implications for respiratory care:

Adverse effects: Hypotension, bradycardia, pruritus, nausea, vomiting. SpO₂ desaturation events.

Sedation score (0 = awake to 3 = unarousable).

Sensory block level: Assessed by pinprick/cotton swab at midclavicular line.

Patient satisfaction: 0 = unsatisfactory, 1 = satisfactory, 2 = excellent.

Catheters were removed after 24 hours, and ambulation initiation was documented.

Statistical Analysis

• Data were analyzed using SPSS version 15.0. Continuous data were expressed as mean ± SD and compared using:
• Unpaired t-test: Intergroup quantitative data.
• Paired t-test: Intra-group comparisons.
• Chi-square test: Categorical data.
• Mann-Whitney U / Wilcoxon signed-rank test: Non-parametric data.

Demographic and Baseline Characteristics

A total of 50 patients undergoing lower limb orthopaedic surgeries were randomized equally into Group E (Epidural block) and Group P (Paravertebral block). Demographic characteristics such as age (p = 0.324), gender (p = 0.564), ASA status, and duration of surgery (p = 0.608) were statistically comparable between the two groups. Baseline mean arterial pressure, heart rate, and SpO₂ were also similar (p > 0.05), ensuring matched group comparisons (Table 1).

Hemodynamic and Oxygen Saturation Parameters

Heart Rate (HR):

Group E demonstrated a statistically significant increase from baseline at 2.5 hours intra-operatively (p = 0.030). Group P, in contrast, showed a significant decrease at 3 h intra-op, 0 h, 1 h, and 24 h post-op. Despite these intra-group variations, intergroup HR differences at all time points were not statistically significant.

Blood Pressure (SBP/DBP):

Group E showed a consistent and significant postoperative decline in both SBP and DBP (p < 0.001). Group P maintained relatively stable readings with no statistically significant intra-group changes. Intergroup differences were not significant.

Mean Arterial Pressure (MAP):

Group E had significantly lower MAP postoperatively at all measured intervals (p < 0.05). In contrast, Group P maintained MAP close to baseline levels. Intergroup comparisons remained statistically non-significant.

Oxygen Saturation (SpO₂):

Both groups maintained oxygen saturation levels >94% throughout the perioperative period. Group P had slightly higher average SpO₂ during early ambulation and recovery, though this was not statistically significant.

Postoperative Pain (VAS Score)

VAS scores at baseline were comparable. Group P showed significantly lower pain scores at 2.5 h intra-op and 24 h post-op (p < 0.05), while other time points did not show significant intergroup differences. Intra-group analysis revealed a greater number of significant pain score increases in Group E than in Group P (Table 3). Rescue boluses were more frequently required in Group E.

Patient Satisfaction and Adverse Effects

Satisfaction Scores:

While both groups had satisfactory outcomes, Group P showed a statistically significant intra-group increase in satisfaction scores at 24 h post-op (p < 0.05). No significant intergroup difference was noted at any time point.

Adverse Effects:

Pruritus occurred more frequently in Group E, affecting 6 patients compared to 2 in Group P. Nausea was reported in 4 patients in Group E and only 1 patient in Group P. Mild sedation (score ≥2) was observed in 4 patients in Group E, whereas no cases of sedation ≥2 occurred in Group P. Although these differences were not statistically significant (p > 0.05), they highlight a trend toward a more favorable side effect profile in the paravertebral group. No serious cardiovascular or respiratory complications occurred in either group.

Analgesic Efficacy (NRS Score)

Numerical Rating Scale (NRS) scores were consistently lower in Group P at all intervals, though intergroup differences were not statistically significant. Within-group analysis showed a significant reduction from baseline in Group P at 6 h and 24 h postoperatively (p < 0.05). Group E showed less consistent analgesic efficacy (Table 5).

Limitations of the Study

Postoperative pain is a significant concern following lower limb surgeries, as it directly influences patient comfort, recovery, early mobilization, and rehabilitation outcomes. This prospective study compared the analgesic efficacy and safety of continuous lumbar epidural block and paravertebral block (PVB), both using 0.5% ropivacaine with fentanyl. While both regional techniques provided effective analgesia, PVB demonstrated superior hemodynamic stability, fewer adverse effects, and comparable patient satisfaction.

Demographic and Surgical Variables

Baseline demographic and surgical characteristics—such as age, sex, ASA classification, and duration of surgery—were comparable between the two groups. This reduced the influence of confounding factors and strengthened the validity of observed differences, aligning with prior studies assessing regional anesthesia in orthopedic populations [1].

Hemodynamic and Respiratory Considerations

Hemodynamic stability is a critical determinant in the choice of regional anesthesia, especially in elderly or comorbid patients. In this study, the epidural group experienced a greater decline in mean arterial pressure (MAP), occasionally requiring pharmacologic support. This aligns with earlier findings highlighting the bilateral sympathetic blockade typical of epidural anesthesia [2,3].

In contrast, the paravertebral group exhibited more stable hemodynamics throughout the perioperative period, consistent with previous reports by Davies et al. and Kotze et al. [4,5]. The localized, unilateral spread of anesthetic in PVB limits sympathetic involvement and contributes to cardiovascular stability [6].

Importantly, respiratory parameters such as oxygen saturation (SpO₂) remained stable in both groups, without episodes of hypoxia or respiratory depression. Although direct spirometric measurements were not recorded, preserved oxygenation and the absence of opioid-induced respiratory compromise in either group highlight the suitability of both techniques for minimizing pulmonary risk. Given that systemic opioids can depress respiration, the use of regional techniques like PVB or epidural block is particularly advantageous in patients with coexisting respiratory concerns.

Analgesic Efficacy

Pain control was effective in both groups, as measured by the Visual Analogue Scale (VAS). Although minor differences were observed at certain intervals, the overall analgesic efficacy was comparable. This is in agreement with Perttunen et al. and Surange et al., who demonstrated similar results using PVB and epidural techniques [7,8].

Rescue analgesic requirements were low in both groups, underscoring the adequacy of continuous local anesthetic infusion. The addition of fentanyl may have contributed to prolonged analgesic effects, consistent with previous findings [9].

Patient Satisfaction and Complications

Patient satisfaction was high across both groups, with a mild upward trend noted in the PVB group during the later postoperative phase. This could be attributed to enhanced hemodynamic tolerance and a lower incidence of side effects. While nausea, vomiting, and pruritus were slightly more frequent in the epidural group, the differences were not statistically significant. Increased incidence of pruritus with epidural use may be due to greater central distribution of fentanyl, as previously observed by Kanazi et al. and Bimston et al. [10,11].

Notably, none of the patients developed respiratory distress, sedation-related hypoventilation, or desaturation requiring intervention—an important consideration in optimizing pain control while preserving pulmonary function in high-risk patients.

Technical Considerations

Paravertebral block provides several technical advantages, particularly in elderly patients or those with altered spinal anatomy due to deformity, spondylosis, or prior surgery. Compared to epidurals, which demand a midline approach and precise needle placement, PVB allows easier administration via a lateral approach with a lower risk of dural puncture and bilateral block. Its unilateral nature facilitates early ambulation, supporting Enhanced Recovery After Surgery (ERAS) protocols [12,13].

Further support for PVB comes from imaging and cadaveric studies showing its feasibility and targeted spread when administered using anatomical landmarks or ultrasound guidance [14,15].

Clinical Implications

Both lumbar epidural and paravertebral blocks are effective for postoperative analgesia following lower limb surgery. However, this study supports the use of PVB as a favorable alternative, offering improved hemodynamic stability, fewer adverse effects, and potential respiratory advantages. For patients with borderline cardiopulmonary reserve or at risk of opioid-induced respiratory depression, PVB may offer a safer analgesic profile without compromising efficacy. While epidural analgesia remains a mainstay in many surgical centers, the safety, simplicity, and clinical benefits of PVB make it a valuable option in contemporary perioperative care.

Limitations

This study has several limitations. First, the sample size was relatively small (n=50), which may limit the generalizability of the findings. A larger multicenter trial would provide more robust evidence. Second, although efforts were made to standardize intraoperative management, subtle variations in surgical duration, blood loss, or fluid administration may have influenced hemodynamic parameters. Third, the study was limited to a 24-hour postoperative observation period; longer-term outcomes such as time to ambulation, length of hospital sta, or chronic pain were not assessed. Lastly, the study was not blinded, which could have introduced observer or patient bias in subjective assessments such as pain and satisfaction scores.

This prospective comparative study evaluated the efficacy of continuous lumbar epidural and paravertebral blocks for postoperative analgesia in patients undergoing lower limb surgeries. Both techniques provided effective pain relief; however, the paravertebral block demonstrated superior hemodynamic stability, fewer complications such as hypotension and pruritus, and greater technical ease—particularly in patients with difficult spinal anatomy.

Given its simplicity, safety profile, and comparable analgesic efficacy, the paravertebral block emerges as a viable and advantageous alternative to the epidural block. Its unilateral action promotes better hemodynamic tolerance, supports early ambulation and physiotherapy, and may reduce the risk of opioid-related respiratory compromise. These attributes make it especially suitable for elderly or high-risk patients where both cardiovascular and respiratory stability are essential to recovery.

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