Objective: To investigate effect of ketamine–bupivacaine in thoracic paravertebral block (TPVB) on acute and chronic pain after breast cancer surgery.

Study Design: Prospective randomized controlled study.

Setting: Cancer Institute.

Methods: Ninety patients were assigned to receive TPVB with 20 ml bupivacaine 0.25% (Group I), combined with ketamine 0.5 mg/kg (Group II) or 1 mg/kg (Group III). Assessments included; analgesia time, post-operative morphine consumption, VAS scores, hemodynamics, sedation, adverse events and Douleur Neuropathic 4 questions (DN4) scores in 1st, 2nd and 3rd post-operative months.

Results: Time to first request of analgesia was (17.76 ± 10.85h) in group I vs. (23.00 ± 1.51h, P = 0.188) and (37.33 ± 2.06h, P < 0.000) in group II and III, with significant difference between group II and III (P < 0.000). Dose of morphine in group I was (10.80 ± 2.53 mg) vs. (7.25 ± 2.31 mg, P = 0.135) and (6.20 ± 1.20 mg, P < 0.02) in group II and III, with no difference between group II and III. VAS scores were lower in Group III compared with group I and II (P < 0.05). Mean DN4 score in 1st month postoperative in Group I was (3.50 ± 0.90) vs. (3.07 ± 1.17, P = 0.114) and (2.70 ± 0.65, P < 0.000) in Group II and III, with no difference between Group II and III. Twelve patients in group I had DN4 Score ≥4 vs. 10 (P = 0.372) and 3 (P < 0.000) patients in group II and III, with significant difference between Group II and III (P < 0.001). DN4 score showed no difference between groups in 2nd and 3rd postoperative months.

Conclusion: Ketamine-bupivacaine in TPVB controlled acute post-operative pain in a dose-dependent manner and decreased DN4 scores one month after breast cancer surgery.

Trial Registration: ClinicalTrials.gov Identifier: NCT02462681.