A Randomized Controlled Trial Comparing Preservative-Free Intrathecal Morphine and Surgical Site Local Anesthetic Infiltration Combined with Conventional Analgesia for Post-Cesarean Section Pain Management
Authors and Affiliations
- Department of Anesthesia and Critical Care, Kibogora Level Two Teaching Hospital, Rwanda
- The Operating Room Global (TORG)
- Department of Anesthesia and Critical Care, King Faisal Hospital, Kigali, Rwanda
- Department of Anesthesia, Kibagabaga Level Two Teaching Hospital, Kigali, Rwanda
- University of Limerick, Limerick, Ireland
- The Robotic Global Surgical Society (TROGSS)
Corresponding author: Pacifique Ishimwe · [email protected]
Abstract
Background: Effective pain control after cesarean section (CS) supports early ambulation and maternal recovery. Preservative-free intrathecal morphine provides prolonged analgesia but causes opioid-related side effects. Surgical-site local anesthetic infiltration with conventional analgesia offers an alternative.
Aim: To compare the efficacy and safety of intrathecal morphine versus surgical-site local anesthetic infiltration combined with conventional analgesia following CS.
Methods: This prospective randomized controlled trial at Kibogora Level Two Teaching Hospital, Rwanda, assessed pain using visual analog scores (VAS) at 2, 6, 12, and 24 hours. Secondary outcomes included analgesic consumption, adverse effects, ambulation, and hospital stay.
Results: Preservative-free intrathecal morphine was associated with lower mean VAS pain scores at 2, 6, and 12 hours than surgical-site local anesthetic infiltration combined with conventional analgesia (all p<0.001). At 24 hours, the local-anesthetic-infiltration plus conventional analgesia group had a lower mean VAS score (4.17±1.10 vs 5.46±1.22; p<0.001). The intrathecal morphine group consumed fewer additional analgesic medications within 24 hours (1.30±0.58 vs 3.65±0.80; p<0.001). Nausea/vomiting and pruritus were more frequent with intrathecal morphine, while sedation and respiratory depression did not differ significantly. Total opioid MME could not be reliably compared.
Conclusion: Intrathecal morphine provided superior early analgesia but more adverse effects, while local infiltration achieved better pain control at 24 hours. Individualized analgesic selection should consider effectiveness, safety, monitoring capacity, and available resources.
Keywords: Cesarean section; Intrathecal morphine; Local anesthetic infiltration; Conventional analgesia; Postoperative pain management.
Study at a Glance
Randomized Participants
54 allocated to intrathecal morphine; 46 to local infiltration plus conventional analgesia.
Early Pain Control
Lower mean pain scores in the intrathecal morphine group at 2, 6, and 12 hours.
Later Pain Control
Lower mean pain score in the local infiltration plus conventional analgesia group.
Research Design and Key Findings
Study Design and Setting
Prospective parallel-group randomized controlled trial at Kibogora Level Two Teaching Hospital, Rwanda, involving 100 women undergoing elective cesarean section under spinal anesthesia.
Interventions
Group A: preservative-free intrathecal morphine (n=54). Group B: surgical-site local anesthetic infiltration combined with conventional analgesia (n=46). Three participants allocated to Group B received intrathecal morphine but remained in Group B for intention-to-treat analysis.
Postoperative Pain Scores (VAS at Rest)
| Time after surgery | Intrathecal morphine (n=54) | LA infiltration + conventional analgesia (n=46) | p-value |
|---|---|---|---|
| 2 hours | 0.93 ± 0.64 | 2.57 ± 0.89 | <0.001 |
| 6 hours | 1.59 ± 0.88 | 4.52 ± 0.94 | <0.001 |
| 12 hours | 2.69 ± 1.13 | 6.37 ± 1.14 | <0.001 |
| 24 hours | 5.46 ± 1.22 | 4.17 ± 1.10 | <0.001 |
Adverse Effects and Recovery Outcomes
| Outcome | Intrathecal morphine | LA infiltration + conventional analgesia | p-value |
|---|---|---|---|
| Nausea/vomiting | 31/54 (57.4%) | 5/46 (10.9%) | <0.001 |
| Pruritus | 25/54 (46.3%) | 2/46 (4.3%) | <0.001 |
| Sedation | 1/54 (1.9%) | 1/46 (2.2%) | 1.000 |
| Respiratory depression | 2/54 (3.7%) | 3/46 (6.5%) | 0.659 |
| Time to first ambulation | 3.38 ± 1.44 hours | 3.16 ± 0.77 hours | 0.678 |
| Hospital stay | 2.91 ± 1.01 days | 3.22 ± 0.94 days | 0.049 |
| Additional analgesic medications within 24 h | 1.30 ± 0.58 | 3.65 ± 0.80 | <0.001 |
Cite This Article
Publication Information
Article History
Received: 29 September 2026
Accepted: 14 October 2026
Available online: 19 October 2026
Journal and License
The Operating Room Global Journal (TORGJ)
ISSN: 3105-3262
Volume 2, Issue 4, December 2026
Pages 41–58
Creative Commons Attribution 4.0 International
Ethics and Trial Registration
Kibogora Level Two Teaching Hospital Research Ethics Committee: 77/HK/02.2026.
TORG Institutional Review Board: TORG-RF-2025-003.
Pan African Clinical Trials Registry: PACTR202604681329855.
Written informed consent obtained.
Funding and Conflicts
No funding received. The authors declared no conflicts of interest.
Authors’ Contributions
P. I.: Conceptualization, methodology, data collection, analysis, drafting, and coordination. E. K.: Methodology, clinical investigation, data collection, and manuscript revision. F. I.: Investigation, data analysis, interpretation, and manuscript revision. Prof. A. A. O.: Supervision, methodology, validation, project administration, and critical manuscript revision. All authors approved the final manuscript.
Full Text and References
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