Cervical myelopathy symptom severity, posterior-based cervical surgical approach, and lower body mass index are associated with postoperative delirium: A retrospective observational study.

Background: Cervical spine surgery is often performed to alleviate symptoms of cervical spondylotic myelopathy (CSM) and/or cervical radiculopathy (CR). Although postoperative delirium (POD) is common after cervical spine surgery, it is not known if CSM, CSM symptom severity, and/or surgical approach (anterior vs. posterior) affect POD incidence or severity. The purpose of this study was to determine 1) If the preoperative diagnosis of CSM was an independent risk factor for POD incidence or severity; 2) Among patients who had CSM, which patient and intraoperative characteristics, including CSM symptom severity, were independently associated with POD incidence or severity. Methods: A retrospective search of the electronic medical record of a tertiary academic medical center identified patients undergoing cervical spine surgery. Patients who had: 1) POD assessments within the first 7 days of surgery (Delirium Observation Screening Scale [DOSS]; and 2) preoperative clinical diagnoses of CSM or CR were selected for analysis. Patient and surgical characteristics were extracted from the medical record, including CSM symptom severity (modified Japanese Orthopedic Association [mJOA] scores). Characteristics that were univariately associated with POD were included in multivariable models to determine characteristics that were independently associated with POD incidence and severity. Results: In the entire cohort (755 patients), POD incidence was (139/755) 18.4%, and 4 characteristics were independently associated with greater POD incidence: posterior-based surgical approach (adjusted odds ratio [aOR]=2.27, p=.0005), greater American Society of Anesthesiologists (ASA) class (aOR=1.66, p=.0432), obstructive sleep apnea (OSA) (aOR=1.76, p=.0280), and depression (aOR = 2.20, p=.0138). In this cohort, POD severity was independently associated with posterior-based surgical approach (Beta coefficient=0.4346, p=.0000) greater ASA class (Beta coefficient=0.1648, p=.0326), and lower preoperative hemoglobin (Beta coefficient=-0.0663, p=.0014). In the CSM subgroup ( Conclusions: For patients who have CSM, more severe symptoms (lower mJOA scores) and lower BMI were independently associated with greater POD severity. In addition, posterior-based surgical procedures were independently associated with greater POD incidence and severity.