Mapping lumbar efferent and afferent spinal circuitries via paddle array in a porcine model.

BACKGROUND: Preclinical models are essential for identifying changes occurring after neurologic injury and assessing therapeutic interventions. Yucatan miniature pigs (minipigs) have brain and spinal cord dimensions like humans and are useful for laboratory-to-clinic studies. Yet, little work has been done to map spinal sensorimotor distributions and identify similarities and differences between the porcine and human spinal cords. NEW METHODS: To characterize efferent and afferent signaling, we implanted a conventional 32-contact, four-column array into the dorsal epidural space over the lumbosacral spinal cord, spanning the L5-L6 vertebrae, in two Yucatan minipigs. Spinally evoked motor potentials were recorded bilaterally in four hindlimb muscles during stimulation delivered from different array locations. Then, cord dorsum potentials were recorded via the array by stimulating the left and right tibial nerves. RESULTS: Utilizing epidural spinal stimulation, we achieved selective left, right, proximal, and distal activation in the hindlimb muscles. We then determined the selectivity of each muscle as a function of stimulation location which relates to the distribution of the lumbar motor pools. COMPARISON WITH EXISTING METHODS: Mapping motoneuron distribution to hindlimb muscles and recording responses to peripheral nerve stimulation in the dorsal epidural space reveals insights into ascending and descending signal propagation in the lumbar spinal cord. Clinical-grade arrays have not been utilized in a porcine model. CONCLUSIONS: These results indicate that efferent and afferent spinal sensorimotor networks are spatially distinct, provide information about the organization of motor pools in the lumbar enlargement, and demonstrate the feasibility of using clinical-grade devices in large animal research.

Fourier-transform radiation thermometry: measurements and uncertainties.

A Fourier-transform radiometer is used to measure blackbody temperatures in the 5001000-K range. The measurements involve collecting mid-infrared spectra at two known reference temperatures and one unknown temperature. The accuracy of the interpolation measurement technique is discussed, and the effects of the uncertainty in the temperature reference points, the voltage ratio measurement, and the wavelength accuracy are described. Temperature accuracy at the 0.5% level has been achieved; the main uncertainty component is caused by the interferometer drift. Directions to reach 100-mk accuracy levels have been identified.

Infant involved in a motor vehicle accident.

The authors present and discuss the differential diagnosis for a 7-month-old infant who was seen in the ED after having been involved in a motor vehicle accident. The infant was subsequently found to have an odontoid fracture. Strict attention to the mechanism of injury is emphasized for appropriate evaluation of this patient's condition. An infant who becomes airborne in a car that is extensively damaged deserves an aggressive workup. In a child of this age, examination for subtle or even quite significant injury is difficult. Therefore the focus should be on the potential for injury. This article addresses the rarity of this injury pattern and discusses factors involved in treatment of cervical spine injuries in pediatric patients. The development of the axis and radiography of the cervical spine in pediatric patients are reviewed also. Neurosurgical treatment options are presented. This case also reminds us to ensure parents understand the proper use of a car seat.

Emergency medical care for open wheel racing events at Indianapolis Raceway Park.

STUDY OBJECTIVES: To analyze open-wheel racing accidents at Indianapolis Raceway Park during six seasons (1988 through 1993) and describe factors that improve driver safety. DESIGN: Retrospective analysis. SETTING: Indianapolis Raceway Park, a three-track racing facility that includes a 0.686-mile banked, paved, and lighted oval track. PARTICIPANTS: Race drivers in three United States Auto Club racing divisions (Midget, Sprint, and Silver Crown). MEASUREMENTS AND MAIN RESULTS: During 61 open-wheel racing events, 57 drivers were evaluated at Indianapolis Raceway Park after crashes. Eighteen were transferred to Methodist Hospital of Indiana; four drivers required admission two to the ICU. There were no driver deaths. CONCLUSION: Although open-wheel racing is one of the most common forms of motorcar racing, there have been no previously published studies regarding injury patterns or medical care at these events. This study reviewed race driver injuries during six seasons of open-wheel racing at the Indianapolis Raceway Park. During 61 open-wheel racing events, no drivers were killed, but two required intensive care hospitalization.