Ultrasound-guided Erector Spinae Plane Block for Postoperative Analgesia in Patients undergoing Open Nephrectomy: A Randomised Controlled Study

Abstract

Introduction: Open nephrectomy poses a challenge for the anaesthesiologist due to its large subcostal incision and association with both somatic and visceral pain. While various methods exist for postoperative pain management, a single modality approach remains largely ineffective in adequate pain management. Epidural analgesia, intravenous Patient Controlled analgesia pumps, and ultrasound-guided peripheral nerve blocks are commonly used. Aim: To evaluate the efficacy of ultrasound-guided Erector Spinae Plane Block (ESPB) as a part of multimodal analgesia for postoperative pain in patients undergoing open nephrectomy, to enhance recovery after surgery. Materials and Methods: This randomised controlled study was conducted at Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand, India, on 48 patients undergoing open nephrectomy. They were randomly assigned to two groups: Group I received ultrasound-guided ESPB, while Group II did not receive a block before anaesthesia reversal. In the Post-Anaesthesia Care Unit (PACU), all patients were kept on intravenous Patient Controlled Analgesia (PCA) morphine, and pain was assessed using the Numeric Rating Scale (NRS) scoring. The time of first analgesic requirement and the total morphine consumption in the first 24 hours were recorded. Patient satisfaction and quality of sleep at night were evaluated using a Likert scale. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) version 25.0. Categorical data were assessed using the Chi-square test, while the Independent t-test/Mann-Whitney test was used to determine the association between continuous data. A p-value of <0.05 was considered statistically significant. Results: There were no significant differences found between the two groups in terms of age (p-value=0.999) and ASA grade (p-value=0.336). The total morphine consumption was lower in the ESP group (11 versus 17.58 mg, p-value <0.0001) compared to the control group. The NRS scores during the follow-up period in the ESP group were consistently lower compared to the control group. The average number of analgesia attempts and demand for rescue analgesia were higher in the control group compared to the ESPB group. A higher proportion of ESPB patients agreed (p-value=0.002) that the overall pain management was good. More patients in the ESPB group agreed that they had slept well at night (41.7% versus 12.50%, p-value=0.023). Conclusion: Ultrasound-guided ESPB was more effective in reducing postoperative pain, facilitating enhanced recovery, and significantly reducing the requirement for opioids in the postoperative period after abdominal surgery such as open nephrectomy.

Keywords

• interventional
• morphine
• pain
• ultrasonography