Influence of vertebral manipulations on the autonomic nervous system

Abstract

Introduction. Although its neurophysiological effects have not been fully elucidated, current evidence suggests the clinical effectiveness of spinal manipulation. Different studies suggest that manual therapy induces changes in the autonomic nervous system (ANS). Recent studies showed that mobilization produced a sympatheticexcitatory effect. However, studies using thrust manipulation appeared to be less consistent in their results.Objectives. The main objective of this review was to evaluate whether spinal manipulation induces effects on the ANS. Another objective was to correlate the changes in the measured variables with the activation or inhibition of the sympathetic or parasympathetic nervous system and with the level of spinal manipulation.Materials and methods. We performed a literature search in the following databases: PubMed, PEDro, CINAHL and OVID, using the keywords «Manipulation, spinal» and «Autonomic Nervous System». The PEDro scale was used to assess the methodological quality.Results. Nine studies met the inclusion criteria. Six trials measured cardiovascular function indicators (blood pressure, heart rate, Heart Rate Variability). Three other trials measured the pupil reaction. In most studies, cervical or upper thoracic region was manipulated.Conclusions. Our review does not provide definitive evidence of the effects of spinal manipulation on the ANS. However, most studies observed the existence of autonomic effects by modifying parameters such as blood pressure or Heart Rate Variability after manipulation. Increased parasympathetic activation probably occurs after cervical and lumbar treatment and increased sympathetic activation after dorsal treatment.