Heat-provoked skin vasodilatation in innervated and denervated trunk dermatomes in human spinal cord injury.
METHODS
Cross-sectional, observational, controlled study.


OBJECTIVE
High spinal cord injury (SCI) results in disruption of sympathetic vasomotor control. Vasodilatation as a response to local heating is a biphasic mechanism: the first phase (neurogenic) is mediated by the axon-reflex and is modulated by activity of sympathetic nerves. Our objective was to determine whether the response to heat provocation in trunk dermatomes may provide a measure of vasomotor sympathetic function in SCI.


METHODS
National Spinal Injuries Centre, Stoke Mandeville Hospital, Buckinghamshire, UK; Autonomic Unit, The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Neurovascular Medicine Unit, Imperial College London at St Mary's Hospital, UK.


METHODS
A total of 30 subjects were studied; 18 had chronic complete SCI (level C6-T11) and 12 were healthy controls.


METHODS
Recordings of skin blood flow (SkBF) were obtained with thermostatic laser Doppler probes placed in the upper trunk (at C4) and lower trunk (T10 or T12) dermatomes.


RESULTS
SkBF at baseline (SkBF(bas)) and SkBF at the first peak of vasodilatation (SkBF(max)) showed no significant differences between SCI and controls either in upper or lower trunk dermatomes. However, the ratio of SkBF(max)/SkBF(bas) was significantly different in lower trunk dermatomes in SCI at C6-T5 level (7.5+/-3.5 PU) compared to SCI at T6-T11 level (3.5+/-1.5 PU) (P < 0.01).


CONCLUSIONS
Measurement of SkBF in response to local heating may provide a safe, noninvasive method to assess integrity of sympathetic spinal pathways to the local vasculature. This may aid the classification of the SCI lesions, as the autonomic component currently is not included in the accepted American Spinal Injury Association scoring.
Nicotra
A
A
Neurovascular Medicine Unit, Faculty of Medicine, Imperial College London at St Mary's Hospital, London, UK.
Asahina
M
M
Young
T M
TM
Mathias
C J
CJ
D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D001808:Blood Vessels / Q000294:innervation / Q000503:physiopathology; D001833:Body Temperature Regulation / Q000502:physiology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003714:Denervation / Q000009:adverse effects; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D010525:Peripheral Nerves / Q000503:physiopathology; D012021:Reflex, Abnormal / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D012867:Skin / Q000098:blood supply / Q000294:innervation / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D017779:Sympathetic Fibers, Postganglionic / Q000503:physiopathology*; D014664:Vasodilation / Q000502:physiology; D014666:Vasomotor System / Q000503:physiopathology