Effects of decompressive operation on cardiac autonomic regulation in patients with cervical spondylotic myelopathy: analysis of blood pressure, heart rate, and heart rate variability.

PURPOSE: To investigate the effects of cervical decompression operation on cardiac autonomic regulation and its relationship to recovery of somatic neurological function in cervical spondylotic myelopathy (CSM) patients.

METHODS

One hundred and thirty-two consecutive patients were enrolled in this study, in which 73 patients received decompression operation and the remaining 59 were treated non-operatively. The follow-up period was 6 months. Baseline and follow-up evaluation included Japanese Orthopaedic Association (JOA) score, office-based blood pressure (BP) measurement, heart rate (HR), and 24-h heart rate variability (HRV) assessment. Relationship between achieved JOA score (final JOA score-baseline score) and changes of BP, HR, and HRV parameters in both operative and non-operative groups was analyzed.

RESULTS

In operative group, patients' JOA score and markers of parasympathetic activity in HRV assessment were significantly higher than baseline level 6 months later. Blood pressure, especially systolic blood pressure (SBP), was significantly downregulated in both hypertension and non-hypertension patients. Mean heart rate was also significantly decreased. Furthermore, achieved JOA score was significantly negatively correlated with changes of SBP, minimal HR, mean HR, maximum HR, but significantly positively correlated with changes of HRV parameters reflecting parasympathetic activity. However, changes of JOA score, BP, HR, and HRV parameters in non-operative group were not significant.

CONCLUSIONS

Cervical decompression operation could improve both somatic neurological function and cardiac autonomic regulation in CSM patients, and achieved JOA score was significantly positively correlated with improvement in HRV and cardiac parasympathetic activity. These slides can be retrieved under Electronic Supplementary Material.