TY - JOUR
T1 - Sensory neurons of the human brachial plexus: a quantitative study employing optical fractionation and in vivo volumetric magnetic resonance imaging.
AU - West, Christian Alexander
AU - McKay Hart, Andrew
AU - Terenghi, Giorgio
AU - Wiberg, Mikael
PY - 2012/5
Y1 - 2012/5
N2 - BACKGROUND: Extensive neuron death following peripheral nerve trauma is implicated in poor sensory recovery. Translational research for experimentally proven neuroprotective drugs requires knowledge of the numbers and distribution of sensory neurons in the human upper limb and a novel noninvasive clinical measure of neuron loss. OBJECTIVE: To compare optical fractionation and volumetric magnetic resonance imaging (MRI) of dorsal root ganglia (DRG) in histological quantification and objective clinical assessment of human brachial plexus sensory neurons. METHODS: Bilateral C5-T1 DRG were harvested from 5 human cadavers for stereological volume measurement and sensory neuron counts (optical fractionator). MRI scans were obtained from 14 healthy volunteers for volumetric analysis of C5-T1 DRG. RESULTS: The brachial plexus is innervated by 425,409 (standard deviation 15,596) sensory neurons with a significant difference in neuron counts and DRG volume between segmental levels (P <.001), with C7 ganglion containing the most. DRG volume correlated with neuron counts (r = 0.75, P <.001). Vertebral artery pulsation hindered C5 and 6 imaging, yet high-resolution MRI of C7, C8, and T1 DRG permitted unbiased volume measurement. In accord with histological analysis, MRI confirmed a significant difference between C7, C8, and T1 DRG volume (P <.001), interindividual variability (CV = 15.3%), and sex differences (P = .04). Slight right-left sided disparity in neuron counts (2.5%, P = .04) was possibly related to hand dominance, but no significant volume disparity existed. CONCLUSION: Neuron counts for the human brachial plexus are presented. These correlate with histological DRG volumes and concur with volumetric MRI results in human volunteers. Volumetric MRI of C7-T1 DRG is a legitimate noninvasive proxy measure of sensory neurons for clinical study.
AB - BACKGROUND: Extensive neuron death following peripheral nerve trauma is implicated in poor sensory recovery. Translational research for experimentally proven neuroprotective drugs requires knowledge of the numbers and distribution of sensory neurons in the human upper limb and a novel noninvasive clinical measure of neuron loss. OBJECTIVE: To compare optical fractionation and volumetric magnetic resonance imaging (MRI) of dorsal root ganglia (DRG) in histological quantification and objective clinical assessment of human brachial plexus sensory neurons. METHODS: Bilateral C5-T1 DRG were harvested from 5 human cadavers for stereological volume measurement and sensory neuron counts (optical fractionator). MRI scans were obtained from 14 healthy volunteers for volumetric analysis of C5-T1 DRG. RESULTS: The brachial plexus is innervated by 425,409 (standard deviation 15,596) sensory neurons with a significant difference in neuron counts and DRG volume between segmental levels (P <.001), with C7 ganglion containing the most. DRG volume correlated with neuron counts (r = 0.75, P <.001). Vertebral artery pulsation hindered C5 and 6 imaging, yet high-resolution MRI of C7, C8, and T1 DRG permitted unbiased volume measurement. In accord with histological analysis, MRI confirmed a significant difference between C7, C8, and T1 DRG volume (P <.001), interindividual variability (CV = 15.3%), and sex differences (P = .04). Slight right-left sided disparity in neuron counts (2.5%, P = .04) was possibly related to hand dominance, but no significant volume disparity existed. CONCLUSION: Neuron counts for the human brachial plexus are presented. These correlate with histological DRG volumes and concur with volumetric MRI results in human volunteers. Volumetric MRI of C7-T1 DRG is a legitimate noninvasive proxy measure of sensory neurons for clinical study.
KW - Dorsal root ganglia
KW - Human
KW - Magnetic resonance imaging
KW - Nerve trauma
KW - Neuroprotection
KW - Sensory neuron death
U2 - 10.1227/NEU.0b013e318241ace1
DO - 10.1227/NEU.0b013e318241ace1
M3 - Article
C2 - 22095219
SN - 1524-4040
VL - 70
SP - 1183
EP - 1194
JO - Neurosurgery
JF - Neurosurgery
IS - 5
ER -