Optimising Perioperative Care in Craniotomy Patients : A Narrative Review of Opioid-free Anaesthesia Approaches

Opioid-free Anaesthesia (OFA) for craniotomy is a method employed increasingly for intraoperative and postoperative pain management with reduced opioid side-effects. Standard opioid regimens, although best for analgesia, cause respiratory depression, sedation, nausea and emesis. OFA employs multimodal therapy and utilises regional modalities, such as scalp blocks and systemic non opioid analgesics, including dexmedetomidine, ketamine, lidocaine, acetaminophen, Non Steroidal Anti-Inflammatory Drugs (NSAIDs) and gabapentinoids, in an effort to preserve stable cerebral physiology and thereby prevent stress reactions. This approach aims to achieve a stable haemodynamic and analgesic profile. The intraoperative management of OFA is supported by titration of the anaesthetics mentioned above, with vigilant observation and add-on depth monitoring of anaesthesia and nociception to maintain analgesia during prolonged and severe stimulation, such as skull pinning, dura opening and incision. Postoperative multimodal pain control is extended for a sufficient time to avoid opioids but encourages recovery and allows early neurologic evaluation. OFA reduces opioid side-effects, optimises patient comfort and even hospital stay, but heterogeneity of population, protocol and outcome necessitates individual treatment and close observation. Risk with OFA is also present, such as haemodynamic instability, residual sedation and insufficiency of analgesia and therefore necessitates close observation and management by rescue analgesic therapy. This narrative review aims to evaluate OFA in terms of pharmacology, intraoperative technique, postoperative outcome, theoretical advantage and limitation and value added in the capacity to differentiate a global view, aggregate deficits of knowledge and build lines of future research with the objective of systematising treatment and maximising perioperative care of neurosurgery patients. The scope of this review extends to examining the broader implications of OFA protocols in the context of reducing opioid use, promoting patient safety and optimising postoperative recovery. It also emphasises the need for future research to establish standardised, evidence-based guidelines that could further enhance the efficacy and safety of OFA in neurosurgery.