Cesarean section represents one of the most frequently performed surgical procedures globally, with postoperative pain management being a critical component of perioperative care. Effective analgesia facilitates early mobilization, reduces the risk of thromboembolic complications, enhances maternal-infant bonding, and improves overall patient satisfaction.

Regional anesthesia techniques, particularly neuraxial blockade, have become the preferred method for cesarean delivery, providing excellent intraoperative conditions while allowing the parturient to remain conscious during the procedure. However, the duration of postoperative analgesia from neuraxial techniques is limited, necessitating supplementary analgesic interventions.^[1]

The transversus abdominis plane (TAP) block has gained considerable attention as an effective adjuvant technique for managing postoperative pain following abdominal surgeries, including cesarean section. This technique involves the injection of local anesthetic agents into the fascial plane between the internal oblique and transversus abdominis muscles, targeting the thoracolumbar nerves that supply the anterior abdominal wall.

Ropivacaine, an amide local anesthetic with favorable pharmacokinetic properties, has emerged as a preferred agent for TAP blocks due to its prolonged duration of action and reduced potential for cardiac and central nervous system toxicity compared to bupivacaine. ^[2]

Buprenorphine, a partial μ-opioid receptor agonist with high receptor affinity and prolonged duration of action, has been investigated as a potential adjuvant to local anesthetics in peripheral nerve blocks. Its unique pharmacological profile provides analgesic effects that may extend beyond those achieved with local anesthetics alone. ^[4]

This study was designed to conduct a rigorous comparison of ropivacaine alone versus ropivacaine combined with buprenorphine in TAP blocks for postoperative analgesia following elective cesarean section.

MATERIALS AND METHODS

Study Design and Setting

This prospective, randomized, double-blind, comparative clinical study was conducted at a tertiary care hospital over a period of four months. The study protocol received approval from the institutional ethics committee, and written informed consent was obtained from all participants prior to enrollment.

Participants

Sample Size: Sixty patients scheduled for elective cesarean section under spinal anesthesia were enrolled in the study and randomly allocated into two equal groups of thirty patients each.

Inclusion Criteria: ^[3]

• Pregnant women aged 18-35 years
• American Society of Anesthesiologists (ASA) physical status classification I or II
• Scheduled for elective cesarean section under spinal anesthesia

Willing to provide informed consent

Exclusion Criteria:

• History of chronic pain or long-term analgesic medication use
• Known allergies to study medications
• Coagulopathy or infection at the injection site
• Complicated pregnancies requiring emergency intervention
• Patient refusal to participate

Randomization and Blinding

Participants were randomized using computer-generated random number tables into two groups:

• Group A: TAP block with 15cc of 0.2% ropivacaine per side
• Group B: TAP block with 14cc of 0.2% ropivacaine plus 1cc of buprenorphine (0.3 mg) per side

An independent anesthesiologist not involved in patient care prepared the study medications to ensure double-blind conditions.

RESULTS

Demographic Characteristics

The demographic characteristics were comparable between groups, with no statistically significant differences observed (Table 1).

Table 1: Demographic Characteristics

Duration of Analgesia

The primary outcome measure demonstrated a statistically significant difference between groups (Table 2). ^[5]

Table 2: Duration of Analgesia

Visual Analogue Scale Pain Scores

Pain intensity assessments revealed significant differences between groups at multiple time points (Table 3, Figure 1).

Table 3: VAS Pain Scores for Postoperative Pain

Rescue Analgesia Requirements

The total consumption of rescue analgesics differed significantly between groups (Table 4, Figure 3).

Table 4: Total Rescue Analgesia Requirement

Adverse Effects Profile

The safety profile of both interventions was assessed through systematic monitoring (Table 5).

Table 5: Occurrence of Side Effects

DISCUSSION

This randomized controlled trial demonstrates that the addition of buprenorphine to ropivacaine in TAP blocks significantly enhances postoperative analgesia following cesarean section. The results provide compelling evidence for the clinical utility of this combination in optimizing pain management strategies for obstetric patients.

The prolonged duration of analgesia observed in the buprenorphine group (9.3 ± 1.7 hours versus 5.6 ± 1.1 hours) represents a clinically meaningful improvement that translates to enhanced patient comfort and reduced healthcare resource utilization. This finding aligns with the pharmacological properties of buprenorphine, which demonstrates high receptor affinity and prolonged receptor occupancy. ^[6]

The significant reduction in VAS pain scores observed from 4 hours postoperatively onward in the buprenorphine group indicates not only prolonged duration but also improved quality of analgesia. This finding is particularly relevant in the context of cesarean recovery, where effective pain control facilitates early mobilization, breastfeeding initiation, and overall maternal well-being.

The opioid-sparing effect demonstrated by the 38% reduction in rescue analgesic consumption in the buprenorphine group has important clinical implications. Reduced reliance on systemic opioids minimizes the risk of opioid-related adverse effects, which are of particular concern in the postpartum period. ^[5]

The safety profile of the buprenorphine combination appears acceptable, with only mild sedation occurring in a small number of patients. This side effect profile is consistent with buprenorphine's known pharmacological properties and did not require clinical intervention in any case

.

CONCLUSIONS

The addition of buprenorphine (0.3 mg) to ropivacaine (0.2%) in TAP blocks significantly enhances the duration and quality of postoperative analgesia following cesarean section. This combination provides prolonged pain relief, reduces the requirement for rescue analgesics, and maintains an acceptable safety profile with minimal additional adverse effects.

These findings support the clinical adoption of buprenorphine as an effective adjuvant to ropivacaine in TAP blocks for obstetric patients undergoing cesarean delivery. The demonstrated benefits of this approach contribute to the optimization of multimodal analgesia strategies and may improve overall patient outcomes in the postoperative period.

Declaration:

Conflicts of interests: The authors declare no conflicts of interest.

Author contribution: All authors have contributed in the manuscript.

Author funding: Nill

REFERENCES

1. Zalon ML. Mild, moderate, and severe pain in patients recovering from major abdominal surgery. Pain Manag Nurs. 2014;15(2):474-481.
2. Gan TJ. Poorly controlled postoperative pain: prevalence, consequences, and prevention. J Pain Res. 2017;10:2287-2298.
3. Tsai HC, Yoshida T, Chuang TY, Yang SF, Chang CC, Yao HY. Transversus abdominis plane block: an updated review of anatomy and techniques. BioMed Res Int. 2017;2017:8284363.
4. Young MJ, Gorlin AW, Modest VE, Quraishi SA. Clinical implications of the transversus abdominis plane block in adults. Anesthesiol Res Pract. 2012;2012:731645.
5. McClure JH. Ropivacaine. Br J Anaesth. 1996;76:300-307.
6. Ray M, Mondal SK, Biswas A. Caudal analgesia in paediatric patients: comparison between bupivacaine and ropivacaine. Indian J Anaesth. 2003;47:275-278.