Quality of life outcomes following cervical decompression for coexisting Parkinson's disease and cervical spondylotic myelopathy

Abstract

Background context: Coexisting Parkinson's disease (PD) and cervical spondylotic myelopathy (CSM) presents a diagnostic and therapeutic challenge due to symptomatic similarities between the diseases. Whereas CSM patients are routinely treated with surgery, PD patients face poorer outcomes following spine surgery. No studies have investigated the quality of life (QOL) outcomes following decompression in coexisting PD and CSM.

Purpose: The purpose of the present study was to characterize QOL outcomes for patients with coexisting PD and CSM following cervical decompression.

Study design/setting: This is a matched cohort study at a single tertiary-care center.

Patient sample: Patients with coexisting PD and CSM undergoing cervical decompression between June 2009 and December 2014 were included. These patients were matched to controls with CSM alone by age, gender, American Society of Anesthesiologists classification, Modified Japanese Orthopaedic Association scores, and operative parameters.

Outcome measures: The primary outcome measure was QOL outcomes assessed by change in the EuroQol 5-Dimensions (EQ-5D), Pain Disability Questionnaire (PDQ), and Patient Health Questionnaire-9 (PHQ-9) at last follow-up (LFU). Change in QOL exceeding the minimal clinically important difference (MCID) was secondary.

Methods: QOL data were collected using the institutional prospectively collected database of patient-reported health status measures. Simple and multivariable regressions were used to assess the impact of PD upon change in QOL.

Results: Eleven PD patients were matched to 44 controls. Control patients experienced QOL improvement across all three measures, whereas PD patients only improved with respect to PDQ(89.9-80.7, p=.03). Despite no significant differences in preoperative QOL, PD patients experienced poorer QOL at LFU in EQ-5D (0.526 vs. 0.707, p=.01) and PDQ (80.7 vs. 51.4, p=.03), and less frequently achieved an EQ-5D MCID (18% vs. 57%, p=.04). However, no differences in the achievement of an MCID in PDQ or PHQ-9 were observed between cohorts. Multivariable regression identified PD as a significant independent predictor of poorer improvement in EQ-5D (β=-0.09, p<.01) and failure to achieve an EQ-5D MCID (odds ratio: 0.08, p<.01).

Conclusions: This is the first study to characterize QOL outcomes following cervical decompression for patients with coexisting PD and CSM. Although myelopathy may have been less severe among PD patients, a significant reduction in pain-related disability was observed following decompression. However, PD predicted diminished improvement in overall QOL measured by the EQ-5D.

Keywords: Cervical spondylotic myelopathy; EQ-5D; Minimal clinically important difference; Multivariable regression; PDQ; PHQ-9; Parkinson disease; Quality of life.