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Objective: To determine if norepinephrine (NE) levels increased during autonomic dysreflexia (AD) hypertension in spinal cord injured rats., Design: Prospective, randomized study of three groups of eight rats that underwent C8 spinal cord transection. Two days postoperatively, catecholamine samples were collected from the animals as follows: group 1 without preoperative chemical sympathectomy using 6-hydroxydopamine (6-OH DA) or induced AD; group 2 with induced AD; and group 3, preoperative chemical sympathectomy with 6-OH DA and induced AD., Setting: Basic science research laboratory in an academic institution., Participants: Sprague-Dawley male rats weighing 300g., Intervention: Three episodes of induced AD hypertension with bowel distension for 1 minute., Results: Results showed a significant difference between groups 1 and 2, 2 and 3, and 1 and 3 (p=.0002, ANOVA, Y1/2, post hoc Tukey). The mean NE levels in groups 1, 2, and 3 were 465+/-400 ng/mL, 1,328+/-1,116 ng/mL, and 31+/-61 ng/mL, respectively., Conclusion: NE increased during AD in the spinal cord injured rat. NE levels were effectively blocked by 6-OH DA when AD was induced. Knowledge of catecholamine levels in this process may assist in determining both pathophysiology and potential pharmacologic treatment options in future human studies.

Objective: To determine which nerve conduction parameters can predict the presence of acute denervation in carpal tunnel syndrome., Setting: The electrodiagnostic laboratories of a hospital and a county hospital district., Design: A retrospective review., Patients: A total of 1,590 consecutive cases from January 1992 to June 1996, diagnosed as having median neuropathy at the wrist., Main Outcome Measures: Evidence of acute denervation on needle electromyography of the abductor pollicis brevis and its relationship to patient age, gender, and parameters obtained from nerve conduction studies, including median sensory latency and amplitude, and median motor latency and amplitude., Results: Logistic regression analysis identified gender, median motor latency, and median motor amplitude (all p < or = .008) as contributing to the prediction of denervation. Needle examination of the cases with a median motor amplitude <7 mV detected 95.3% (141/148) of all cases with denervation and could have spared 52% (708/1,362) of the population from a needle examination of the abductor pollicis brevis., Conclusion: The median motor amplitude can predict the presence of acute denervation in the thenar muscles in median neuropathy at the wrist and possibly eliminate a painful needle examination of the median-innervated thenar muscles in over 50% of the cases.

Objective: To characterize the extent and degree of severity in subjects with gunshot wounds (GSWs) to the brachial plexus and to investigate the association between type of injuries and the predominant level involved., Design: A cross-sectional, retrospective review of electrophysiologic data., Setting: Electromyography laboratory of a county hospital., Patients: Thirty consecutive patients with GSWs and 14 patients with traction brachial plexopathies during a 5-year period (1992 through 1996)., Main Outcome Measures: The injury was categorized according to the level predominantly involved, and each component of the four major levels of the plexus was analyzed. The association between type of injury and predominant level involved was assessed via two-tailed chi 2 test. The mean number of elements per subject to each level involved was compared between GSW and motor vehicle accident (MVA) patients using unpaired t test., Results: The type of injury (GSW vs MVA) is significantly associated with the level involved. GSWs were implicated in infraclavicular rather than supraclavicular injury. Compared with MVA, the GSW plexopathies had significant lower mean number of components involved at the root and cord levels, but higher at the terminal nerve branches of plexus. In GSWs, nearly two thirds of all components were severely injured and 60% were completely damaged., Conclusion: These findings demonstrate that gunshot plexopathies are characterized with multielement distribution and a mixture of lesions with or without continuity.