The risk factors associated with delirium after lumbar spine surgery in elderly patients

Abstract

Background: To prospectively explore the incidence and risk factors for postoperative delirium in elderly patients following lumbar spine surgery.

Methods: This prospective study enrolled 148 consecutive patients over the age of 65 who were scheduled to undergo spine surgery. Patients were screened for delirium using the short Confusion Assessment Method (CAM) postoperatively. Patient demographics and relevant medical information were collected. Logistic regression analysis was used to identify the risk factors associated with postoperative delirium.

Results: Eighty-three patients (56.1%) who underwent lumbar spine surgery (not coexisting with cervical or thoracic spine surgery) were enrolled in our study. Post-operative delirium was noted in 14.5% of patients over 65 years old. The presence of preoperative Parkinsonism was significantly higher in the delirium group (41.7% vs. 8.5%, P=0.002), as was a higher preoperative C-reactive protein (CRP) (7.0±15.2 vs. 1.3±2.3 mg/L, P=0.017) when compared with the non-delirium group. Of the risk factors, male sex [odds ratio (OR) =0.10, 95% confidence interval (CI): 0.01-0.66, P=0.017], Parkinsonism (OR =5.83, 95% CI: 1.03-32.89, P=0.046), and lower baseline MMSE score (OR =0.71, 95% CI: 0.52-0.97, P=0.032) were independently associated with postoperative delirium in elderly patients undergoing lumbar spine surgery.

Conclusions: Post-operative delirium occurred in 14.5% of elderly patients who underwent lumbar spine surgery. Male sex, Parkinsonism, and lower baseline MMSE score were identified as independent risk factors for postoperative delirium in elderly patients following lumbar surgery.

Keywords: Delirium; elderly patients; lumbar surgery; risk factors.

Figure 1

Participant enrollment. Enrollment in the study excluded the following: (I) patients did not meet inclusion criteria (n=42); (II) surgeries were temporarily cancelled before operations (n=2); (III) patients underwent the lumbar surgery combining cervical or thoracic surgery (n=21).

Figure 2

Spinal fusion and non-fusion surgery were partial inclusion criteria for this study. (A,B) An 80-year-old female patient who underwent laminectomies at L3/4 and L4/5 did not suffer postoperative delirium; (C,D) another elderly woman who received a spinal fusion at L3/4 and L4/5 (red arrows) suffered delirium postoperatively.

Figure 3

MRI scans showed cerebrovascular accident in some patients with/without delirium. (A) The elderly patient with postoperative delirium had cerebral infarction in the right occipitotemporal lobe (red arrows); (B) susceptibility-weighted imaging revealed the old infarction; (C) diffusion-weighted imaging showed cerebral infarction with hemorrhage during the patient’s first admission; (D) magnetic resonance angiography (3dTOF) showed the old infarction lesion and intracranial blood vessels.