In Vivo Diffusion-Weighted Magnetic Resonance Microscopy of Rat Spinal Cord: Effect of Ischemia and Intrathecal Hyperbaric 5% Lidocaine. Issue 4 (1st July 1999)

• Record Type: Journal Article
• Authors: Benveniste, Helene; Qui, Hui; Hedlund, Laurence W.; Hüttemeier, Peter C.; Steele, Susan M.; Johnson, G. Allan
• Is Part Of: Regional anesthesia and pain medicine. Volume 24:Issue 4(1999)
• Page Start: 311-318
• Page End: 311-318
• Publication Date: 1999-07-01
• Subjects: diffusion -- hyperbaric 5% lidocaine -- ischemia -- magnetic resonance microscopy -- rat -- spinal catheters.; Conduction anesthesia -- Periodicals; Pain medicine -- Periodicals; 617.964
• DOI: 10.1136/rapm-00115550-199924040-00006
• Languages: English
• ISSNs: 1098-7339

Abstract

Abstract : Background and Objectives: Pathophysiologic mechanisms underlying persistent neurologic deficits after continuous spinal anesthesia using hyperbaric 5% lidocaine are still not well understood. It has been suggested that high-dose intrathecal lidocaine induces irreversible conduction block and even ischemia in white matter tracts by breakdown of the blood-nerve barrier. In this study, we use diffusion-weighted magnetic resonance microscopy to characterize the effect of intrathecal hyperbaric 5% lidocaine in rat spinal cord. The parameter measured with DWM, is an "apparent diffusion coefficient, " (ADC), which can be used to exclude the presence of ischemia. Methods: Female Fischer CDF rats were used. Group 1 (n = 5) was exposed to ischemia, group 2 (n = 7) was exposed to intrathecal 5% hyperbaric lidocaine, and group 3 (n = 5) was exposed to intrathecal 7.5% glucose. Diffusion-weighted MR images in group 1 were acquired before and after ischemia induced by cardiac arrest and in groups 2 and 3 rats prior to and during perfusion of the spinal catheter with either 5% hyperbaric lidocaine or 7.5% glucose. Results: Ischemia decreased the ADC by 40% in gray matter and by 30% in white matter of spinal cord. Continuous intrathecal anesthesia with hyperbaric 5% lidocaine did not affect the spinal cord ADC. Further, 7.5% intrathecal glucose had no effect on ADCs in gray or white matter of spinal cord. Conclusions: Ischemia reduced the ADC in both spinal cord white and gray matter. Hyperbaric 5% lidocaine did not affect the spinal cord ADC during the first 1.5 hours. We suggest that 5% hyperbaric lidocaine does not induce irreversible neurologic deficits by causing spinal cord ischemia.