Hotz-Boendermaker S.1, Hangartner B.1, Cooke C.1, Luomajoki H.1
1Zurich University of Applied Sciences, Institute of Physiotherapy, Winterthur, Switzerland
Background: A large group of chronic low back pain (CLBP) patients shows impaired postural control. Little evidence exists to confirm that CLBP patients with movement control impairment show reduced oxygenation in back muscles compared to healthy subjects1.
Purpose: To determine whether erector spinae muscle oxygenation differs during movement control testing between patients with nonspecific CLBP and a control group. We hypothesized that even at moderate levels of activation, low back muscles would show a contrasting oxygenation level between the two groups.
Methods: The study design was a cross-sectional comparative study between 20 healthy controls and a subgroup of 12 nonspecific CLBP patients with movement control impairment. Participants performed three movement control tests (waiters bow, sitting knee extension and prone knee bend)2 while oxygenation was measured using functional near infrared spectroscopy (fNIRS). A portable multi-channel continuous wave fNIRS imaging system (NIRSport, NIRx Medical Technologies LLC) operating at 760 nm and 850 nm was employed. The NIRStar Software 14.0 (NIRx Medical Technologies LLC) was used for data recording. Probes were placed bilaterally at the centre of the erector spinae at the level of L3, using 2 channels on each side. On the first level, individual fNIRS based physiological changes of oxygenation were calculated between activation and a rest period prior to the movement testing, by using NIRSlab v2016.01. Subsequent between group differences in the changes of oxygenation were computed using IBM SPSS 19.
Results: The fNIRS signal revealed significant physiological changes of oxygenation during movement, compared to the rest period. Preliminary analysis however did not demonstrate statistical differences between the control and the CLBP group.
Conclusion(s): fNIRS appears to be a feasible non-invasive technology to investigate back muscle oxygenation during low level activation. The present investigation did not support previous findings of reduced capacity for the delivery of oxygen to the erector spinae muscle during activity of the lower back muscle in CLBP with movement control impairment.
Implications: The widely used isotonic exercise therapy is the most common conservative intervention for CLBP patients and seems not to be influenced by muscle oxygenation. The focus of further fNIRS investigations should therefore be on isometric muscle contraction, as a potential source of low back pain.
1) Olivier, N. et al. (2013). An exercise therapy program can increase oxygenation and blood volume of the erector spinae muscle during exercise in chronic low back pain patients. Arch Phys Med Rehabil, 94(3).
2) Luomajoki, H. et al. (2008). Movement control tests of the low back; evaluation of the difference between patients with low back pain and healthy controls. BMC Musculoskeletal Disorders.
Funding acknowledgements: Zurich University of Applied Sciences, School of Health Professions, Institute of Physiotherapy, Winterthur, Switzerland
Topic: Musculoskeletal: Spine
Ethics approval: This study was approved by the Ethics Committee of the Canton of Zurich, Switzerland.
All authors, affiliations and abstracts have been published as submitted.
