Neurocognitive monitoring in patients undergoing opioid pain medication after spinal surgery: a feasibility study of a new monitoring method

Purpose: Patients undergoing spinal surgery require postoperative pain management to alleviate wound pain. Pain medication includes WHO grade 1 analgesic as well as potent opioids, potentially leading to cognitive decline. Up until now, the cognitive impairment is only poorly studied and difficult to monitor. We hereby investigate the feasibility of a digital monitoring method for neurocognitive function under opioid medication after spinal instrumentation. Methods: Prospective monocenter feasibility study enrolling patients before undergoing spinal surgery. We performed cognitive testing using a tablet-based application before (baseline), as well as on day 2 after surgery (intravenous opioids), before discharge (oral opioids), and at follow-up. We recorded the exact pain medication and its other side effects. Potential risk factors for the postoperative decline in cognition included age, high-dose opioid application, and length of surgery. Results: We included 20 patients in our study. The baseline assessment revealed no cognitive impairment before surgery. All patients underwent dorsal instrumentation for degenerative (60%), osteoporotic fracture (15%), or spinal tumor (25%) indications. Cognitive testing after surgery showed a significant decline under intravenous opioid therapy including short time and delayed verbal recall (p < 0.001) as well as arithmetic fluency. Cognitive performance significantly improved with partial recovery until follow-up and opioid discontinuation. Conclusion: Cognition testing and monitoring of neurocognitive decline under high-dose opioid medication were feasible using the digital tablet-based application. The cognition app helps to identify difficulties in cognitive function as a side effect of overdosage in opioid medication, and care givers should evaluate the risk of non-comprehension and impaired informed consent appropriately.