Postoperative cognitive dysfunction in non-elderly patients with or without chronic pain

Abstract

Objective Postoperative cognitive dysfunction (POCD) is a common complication with advanced age, perioperative pain and major surgery as risk factors. However, whether pre-operative long-term pain can influence postoperative cognitive status in non-geriatric population is unclear. This study aimed to investigate the relationship of preoperative chronic pain and POCD in non-elderly patients who underwent arthroscopic surgery. Methods An observational longitudinal cohort study of POCD was conducted in patients aged 18 to 59 years who underwent arthroscopic surgery in Huashan Hospital (Shanghai, China) between January 2016 and December 2016. Pain intensity was estimated by visual analog scale (VAS), cognitive function was assessed by Syndrom Kurz Test (SKT) and compared between observational group (OG, with chronic pain) and control group (CG, without chronic pain) pre- and post-operatively. Follow-up evaluations were conducted within 24 h, 2 weeks, 6 weeks and 3 months after surgery. Results Fifty-seven patients completed the follow-up. Twenty-five patients (44%) had preoperative chronic pain and 32 patients (56%) did not. OG patients had a worse performance of SKT than CG before surgery (P=0.010, 0.025, 0.010). Throughout the follow-up period, OG had lower scores than CG. OG patients had a pain relief postoperatively (P=0.001). Both OG and CG had an SKT score improvement. The incidence of POCD between two groups was similar at 24 h after surgery (4% vs. 3%). The incidence of POCD with or without chronic pain at follow-up point was 0. Conclusion The incidence of POCD in non-elderly population who underwent arthroscopic surgery was low. Preoperative chronic pain won’t deteriorate postoperative cognitive impairment, but pain diminishment can lead to cognitive function improvement. Key words: Postoperative cognitive dysfunction; Chronic pain; Non-elderly population