BACKGROUND Evidence indicates that, over time, patients with spinal cord injury (SCI) improve neurologically in various degrees. We sought to further investigate indicators of grade conversion in cervical SCI. OBJECTIVE To detect predictors of ASIA impairment scale (AIS) grade conversion in SCI following surgical decompression. METHODS In a retrospective study, demographics, clinical, imaging, and surgical data from 100 consecutive patients were assessed for predictors of AIS grade conversion. RESULTS American Spinal Injury Association motor score was 17.1. AIS grade was A in 52%, B in 29%, and C in 19% of patients. Surgical decompression took place on an average of 17.6 h following trauma (≤12 h in 51 and >12 h in 49). Complete decompression was verified by magnetic resonance imaging (MRI) in 73 patients. Intramedullary lesion length (IMLL) on postoperative MRI measured 72.8 mm, and hemorrhage at the injury epicenter was noted in 71 patients. Grade conversion took place in 26.9% of AIS grade A patients, 65.5% of AIS grade B, and 78.9% of AIS grade C. AIS grade conversion had statistical relationship with injury severity score, admission AIS grade, extent of decompression, presence of intramedullary hemorrhage, American Spinal Injury Association motor score, and IMLL. A stepwise multiple logistic regression analysis indicated IMLL was the sole and strongest indicator of AIS grade conversion (odds ratio 0.950, 95% CI 0.931–0.969). For 1- and 10-mm increases in IMLL, the model indicates 4% and 40% decreases, respectively, in the odds of AIS grade conversion. CONCLUSION Compared with other surrogates, IMLL remained as the only predictor of AIS grade conversion.

We studied single Ca2+ channels in smooth muscle cells from the basilar artery of the guinea pig using conventional patch-clamp techniques. With 40 mM or 90 mM Ba2+ as the charge carrier, a 23-pS inward current channel was observed in 46/187 cell-attached patches studied without the dihydropyridine, BAY K8644, in the pipette solution. At 0 mV, this channel exhibited short and long openings with time constants of 1.03 and 3.65 ms, respectively. The probability of channel opening was voltage dependent with half-activation occurring at +9.9 mV. In 14/26 patches tested, addition of 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) to the bath increased the probability of opening at -10 mV by a factor of 2.6, from 0.0272 +/- 0.0429 to 0.0695 +/- 0.0788 (P < 0.01, paired t-test). Mean data from five patches fit to a Boltzmann function indicated that at positive potentials, the probability of opening increased by a factor of 1.7, from 0.352 to 0.600, whereas the voltage dependence, the number of channels, the number of open states, the time constants of the open states, and the proportion of time spent in each open state were unchanged. When BAY K8644 was added to the pipette solution, the 23-pS channel was observed in nearly all patches (62/66), but the voltage dependence of activation was shifted -15.3 mV compared to control. In some patches studied with 90 mM Ba2+, a 9-pS inward current channel also was observed and its activity also was increased significantly by 8-Br-cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)