Efficacy of single-injection unilateral thoracic paravertebral block for post open cholecystectomy pain relief: a prospective randomized study at Gondar University Hospital

BACKGROUND Cholecystectomy can be associated with considerable postoperative pain. While the benefits of paravertebral block (PVB) on pain after thoracotomy and mastectomy have been demonstrated, not enough investigations on the effects of PVB on pain after open cholecystectomy have been conducted. We tested the hypothesis that a single-injection thoracic PVB reduces pain scores, decreases opioid consumption, and prolongs analgesic request time after cholecystectomy. METHODS Of 52 patients recruited, 50 completed the study. They were randomly allocated into two groups: the paravertebral group and the control group. The outcome measures were the severity of pain measured on numeric pain rating scale, total opioid consumption, and first analgesic request time during the first postoperative 24 hours. RESULT The main outcomes recorded during 24 hours after surgery were Numerical Rating Scale (NRS) pain scores (NRS, 0-10), cumulative opioid consumption, and the first analgesic request time. Twenty four hours after surgery, NRS at rest was 4 (3-6) vs 5 (5-7) and at movement 4 (4-7) vs 6 (5-7.5) for the PVB and control groups, respectively. The difference between the groups over the whole observation period was statistically significant (P<0.05). Twenty-four hours after surgery, median (25th-75th percentile) cumulative morphine consumption was 0 (0-2) vs 2.5 (2-4) mg (P<0.0001) and cumulative tramadol consumption was 200 (150-250) mg vs 300 (200-350) mg in the paravertebral and in the control group, respectively (P=0.003). After surgery, the median (25th-75th percentile) first analgesic requirement time was prolonged in the PVB group in statistically significant fashion (P<0.0001). CONCLUSION AND RECOMMENDATIONS Single-shot thoracic PVB as a component of multi-modal analgesic regimen provided superior analgesia when compared with the control group up to 24 postoperative hours after cholecystectomy, and we recommend this block for post cholecystectomy pain relief.