Comparison of different volumes spread of erector spinae block in postmastectomy pain syndrome management: a prospective randomized comparative study

BACKGROUND: Postmastectomy pain is chronic pain that occurs in females after breast surgeries. In this study, we estimated the vertebral levels reached by two different volumes (20 ml and 30 ml solutions) in the erector spinae block (ESB), as well as assess pain improvement and patient satisfaction in females with postmastectomy pain syndrome. METHODS: Fifty patients were assigned to two groups. The 20 ml group received ESB with 10 ml of bupivacaine 0.5%, 1 ml of 40 mg/ml of methylprednisolone, 2 ml of non-ionic contrast, and 7 ml of saline 0.9%. The 30 ml group received ESB with 15 ml of bupivacaine 0.5%, 1 ml of 40 mg/ml of methylprednisolone, 2 ml of non-ionic contrast, and 12 ml of saline 0.9%. RESULTS: The mean numbers of the blockade segments were 5.12 ± 0.726 and 6.36 ± 0.569 in the 20 ml and 30 ml groups, respectively (P < 0.001). The T1 to T6 blockade levels were achieved in six patients (24%) in the 20 ml group, versus 23 patients (92%) in the 30 ml group (P < 0.001). The numerical rating scale (NRS) improved in the 30 ml group during the follow-up period, compared to the 20 ml group. The T1 to T6 blockade levels showed better NRS (P < 0.001) and patient satisfaction (P = 0.011) than other blockade levels. CONCLUSIONS: The injection of a 30 ml solution of 0.25% bupivacaine with methylprednisolone in erector spinae block (ESB) may result in better analgesia and higher patient satisfaction in individuals with postmastectomy pain syndrome (PMPS) compared to a 20 ml solution. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05192278) on 14/1/2022.