To evaluate the effects of multimodal general anesthesia on the recovery profile of elder patients undergoing lumbar spine fusion surgery.

Multimodal general anesthesia has been proposed in recent years. By administration of multiple agents acting on a different component of the nociceptive pathways, the multimodal general anesthesia may elicit maximal anesthetic effects with minimal anesthetic dose. These may be beneficial to improve postoperative recovery and reduce adverse effects such as postoperative delirium and perioperative neurocognitive impairment. It is not uncommon that elder patients undergoing lumbar spine fusion surgery suffer from postoperative poor recovery, postoperative delirium as well as the postoperative neurocognitive disorder. Therefore, this study aims to explore the potential effects of multimodal general anesthesia, which comprised with electroencephalography density spectrum array guided co-administration of sevoflurane, ketamine and dexmedetomidine, on the postoperative recovery profiles for elder patients undergoing lumbar spine fusion surgery.

Inclusion criteria:

1. patients with ages at least 60-year undergoing elective lumbar spine surgery

Exclusion:

1. A history of dementia
2. Impaired liver function, eg. AST or ALT >100; liver cirrhosis > Child B class
3. Impaired renal function, cGFR< 60 ml/min/1.73 m2
4. Cardiac dysfunction, such as heart failure > NYHA class II