Background: Thoracic segmental spinal anaesthesia (TSSA) is a refined regional technique that targets specific dermatomes, offering hemodynamic stability and enhanced postoperative outcomes. Among local anaesthetics, isobaric ropivacaine and isobaric levobupivacaine with adjuvants such as dexmedetomidine are gaining popularity for TSSA in abdominal surgeries.

Aim: To compare the efficacy and safety of isobaric ropivacaine versus isobaric levobupivacaine with dexmedetomidine in thoracic segmental spinal anaesthesia for intra-abdominal surgeries.

Methods: This randomized controlled trial included 60 ASA I–II patients undergoing elective intra-abdominal surgeries under TSSA. Patients were randomly assigned into two groups:

● Group RD: Received isobaric ropivacaine 0.5% (2.5cc) with dexmedetomidine 10 μg

● Group LD: Received isobaric levobupivacaine 0.5% (2.5cc) with dexmedetomidine 10μg

Primary outcomes included onset and duration of sensory and motor block. Secondary outcomes included duration of analgesia, hemodynamic stability, and adverse effects.

Results: Group LD had a significantly faster sensory onset time (4.1 ± 0.6 min) compared to Group RD (5.2 ± 0.8 min) (p<0.05). Duration of analgesia was longer in Group LD (312 ± 26 min) than Group RD (234 ± 20 min) (p<0.001). Group LD also demonstrated a deeper and prolonged motor block. Both groups maintained stable hemodynamics, although mild bradycardia was observed in a few patients in Group LD.

Conclusion: Isobaric levobupivacaine with dexmedetomidine provides superior block characteristics and prolonged analgesia compared to isobaric ropivacaine, without compromising hemodynamic safety. It may be preferred in Thoracic segmental spinal anaesthesia(TSSA) for intra-abdominal surgeries.