Excitability and recruitment patterns of spinal motoneurons in human sleep as assessed by F-wave recordings

This study examines the excitability and recruitment of spinal motoneurons in human sleep. The main objective was to assess whether supraspinal inhibition affects the different subpopulations of the compound spinal motoneuron pool in the same way or rather in a selective fashion in the various sleep stages. To this end, we studied F-conduction velocities (FCV) and F-tacheodispersion alongside F-amplitudes and F-persistence in 22 healthy subjects in sleep stages N2, N3 (slow-wave sleep), REM and in wakefulness. Stimuli were delivered on the ulnar nerve, and F-waves were recorded from the first dorsal interosseus muscle. Repeated sets of stimuli were stored to obtain at least 15 F-waves for each state of vigilance. F-tacheodispersion was calculated based on FCVs using the modified Kimura formula. Confirming the only previous study, excitability of spinal motoneurons was generally decreased in all sleep stages compared with wakefulness as indicated by significantly reduced F-persistence and F-amplitudes. More importantly, F-tacheodispersion showed a narrowed range of FCV in all sleep stages, most prominently in REM. In non-REM, this narrowed range was associated with a shift towards significantly decreased maximal FCV and mean FCV as well as with a trend towards lower minimal FCV. In REM, the lowering of mean FCV was even more pronounced, but contrary to non-REM sleep without a shift of minimal and maximal FCV. Variations in F-tacheodispersion between sleep stages suggest that different supraspinal inhibitory neuronal circuits acting on the spinal motoneuron pool may contribute to muscle hypotonia in human non-REM sleep and to atonia in REM sleep.

Epidemiology and predictors of spinal injury in adult major trauma patients: European cohort study

This is a European cohort study on predictors of spinal injury in adult (≥16 years) major trauma patients, using prospectively collected data of the Trauma Audit and Research Network from 1988 to 2009. Predictors for spinal fractures/dislocations or spinal cord injury were determined using univariate and multivariate logistic regression analysis. 250,584 patients were analysed. 24,000 patients (9.6%) sustained spinal fractures/dislocations alone and 4,489 (1.8%) sustained spinal cord injury with or without fractures/dislocations. Spinal injury patients had a median age of 44.5 years (IQR = 28.8-64.0) and Injury Severity Score of 9 (IQR = 4-17). 64.9% were male. 45% of patients suffered associated injuries to other body regions. Age <45 years (≥45 years OR 0.83-0.94), Glasgow Coma Score (GCS) 3-8 (OR 1.10, 95% CI 1.02-1.19), falls >2 m (OR 4.17, 95% CI 3.98-4.37), sports injuries (OR 2.79, 95% CI 2.41-3.23) and road traffic collisions (RTCs) (OR 1.91, 95% CI 1.83-2.00) were predictors for spinal fractures/dislocations. Age <45 years (≥45 years OR 0.78-0.90), male gender (female OR 0.78, 95% CI 0.72-0.85), GCS <15 (OR 1.36-1.93), associated chest injury (OR 1.10, 95% CI 1.01-1.20), sports injuries (OR 3.98, 95% CI 3.04-5.21), falls >2 m (OR 3.60, 95% CI 3.21-4.04), RTCs (OR 2.20, 95% CI 1.96-2.46) and shooting (OR 1.91, 95% CI 1.21-3.00) were predictors for spinal cord injury. Multilevel injury was found in 10.4% of fractures/dislocations and in 1.3% of cord injury patients. As spinal trauma occurred in >10% of major trauma patients, aggressive evaluation of the spine is warranted, especially, in males, patients <45 years, with a GCS <15, concomitant chest injury and/or dangerous injury mechanisms (falls >2 m, sports injuries, RTCs and shooting). Diagnostic imaging of the whole spine and a diligent search for associated injuries are substantial.

Spinal and pelvic injuries in airborne sports: a retrospective analysis from a major Swiss trauma centre

Adrenalin-seeking airborne sports like BASE-jumping, paragliding, parachuting, delta-gliding, speedflying, and skysurfing are now firmly with us as outdoor lifestyle activities and are associated with a high frequency of severe injuries, especially to the spine.