Intrathecal Isobaric Versus Hyperbaric 0.5% Levobupivacaine in Turp Surgeries: A Systematic Review

Abstract

Background: Transurethral resection of the prostate (TURP) is usually performed in elderly men with significant cardiovascular and respiratory comorbidities. Spinal anaesthesia is often preferred because it facilitates early detection of complications such as fluid overload and TURP syndrome and avoids airway manipulation in high-risk patients.1 Levobupivacaine, the S-enantiomer of bupivacaine, provides long-acting neuraxial anaesthesia with a more favourable cardiovascular and central nervous system safety profile than racemic bupivacaine, making it attractive in this population.2 However, there is ongoing debate about whether isobaric or hyperbaric 0.5% levobupivacaine offers the best balance between block reliability, haemodynamic stability and recovery characteristics in TURP. Objectives: To synthesise evidence from randomized controlled trials (RCTs) directly or indirectly comparing intrathecal isobaric and hyperbaric 0.5% levobupivacaine in TURP and closely related infra-umbilical procedures, focusing on block characteristics, haemodynamic effects, complications and recovery, and to discuss implications for anaesthetic practice. Methods: A narrative review of RCTs and prospective comparative studies was conducted using PubMed, Google Scholar and major anaesthesia journals up to November 2025. Studies were eligible if they evaluated intrathecal 0.5% levobupivacaine in adults undergoing TURP or infra-umbilical surgery and directly compared isobaric with hyperbaric formulations, or provided baricity-relevant data. Additional TURP-specific trials using levobupivacaine with opioid adjuvants or alternative dosing regimens were included for context. Outcomes included onset and duration of sensory and motor block, maximum block height, haemodynamic changes, vasopressor requirements, adverse effects and recovery times. Due to heterogeneity, no formal meta-analysis was performed; results are summarised descriptively. Results: A pivotal RCT in transurethral endoscopic urological surgery (predominantly TURP) compared 13.5 mg intrathecal 0.5% hyperbaric versus isobaric levobupivacaine and found that the hyperbaric solution produced faster onset of T10 sensory block, more rapid attainment of maximum block height and shorter motor block duration, with similar peak block level, duration of analgesia and side-effect profile.4 A recent three-arm RCT in elective TURP using low-dose levobupivacaine with intrathecal fentanyl reported earlier onset and longer sensory block with hyperbaric levobupivacaine compared with plain (isobaric) levobupivacaine, without deterioration in haemodynamic stability.5 Trials in lower-limb orthopaedic and intra-abdominal surgery similarly show earlier onset and more predictable spread with hyperbaric levobupivacaine, whereas isobaric preparations provide more gradual onset and slightly lower cephalad spread, with broadly comparable duration of anaesthesia.6-8 TURP-specific studies of isobaric levobupivacaine, alone or with intrathecal opioids, demonstrate adequate surgical conditions, stable haemodynamics and favourable recovery in elderly patients.2,9-11,14,15Conclusion: Existing RCT evidence suggests that, for TURP, hyperbaric 0.5% levobupivacaine provides faster onset and slightly more predictable block characteristics than isobaric levobupivacaine, while maintaining similar overall duration of anaesthesia and haemodynamic safety. Isobaric levobupivacaine remains a reasonable alternative when a more gradual and potentially lower block is desired. Choice of baricity should be individualised according to patient comorbidities, anticipated surgical duration and institutional experience. Further highquality RCTs focused on elderly TURP populations and patient-centred outcomes (early mobilisation, urinary function, discharge readiness) are warranted.