Neurocognitive Monitoring in Patients Undergoing Opioid Pain Medication After Spinal Surgery: A Feasibility Study of a New Monitoring Method

Introduction: Patients undergoing spinal surgery usually require postoperative pain management to alleviate wound pain. Pain medication includes WHO grade 1 analgesic but also potent opioids, potentially leading to severe side effects such as fatigue, nausea and cognitive decline. Up to now, the cognitive impairment due to postoperative pain protocols is only poorly studied.

Methods: We performed a prospective monocenter feasibility study enrolling patients before undergoing spinal surgery. Cognitive testing was performed using a tablet-based application before surgery (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 other side effects from the medication. Potential risk factors for postoperative decline in cognition were age, high-dosed opioid application, length of surgery and blood loss.

Results: We included 20 patients in our study. Median age was 67 years. Baseline assessment revealed no cognitive impairment before surgery. All patients underwent a dorsal instrumentation in our neurosurgical department for degenerative (60%), osteoporotic fracture (15%) or tumor (25%) indication. Cognitive testing after surgery showed a significant decline under intravenous opioid therapy including short time and delayed recall word listing as well as logic testing including arithmetic fluency (p < 0.001). Cognitive performance significantly improved with recovery until follow-up and opioid discontinuation.

Conclusion : Cognitive assessment in patients undergoing spinal surgery with postoperative opioid medication revealed a postoperative impairment under intravenous medication. Side effects should be monitored closely, and cognitive decline should be considered in follow-up operation informed consent.