Abstract:The technique of lumbar sympathetic nerve modulation refers to the use of physical methods (such as radiofrequency thermal ablation) or chemical agents (such as local anesthetics or neurolytic agents) to act on the lumbar sympathetic ganglia or chain in order to modulate (anesthetize, deactivate, or block) nerve conduction function. Determining the success of the blockade is currently a key concern for pain physicians. Initially, peripheral temperature monitoring was used to indirectly measure changes in blood flow to evaluate the success of the block, commonly utilizing thermometers, temperature probes, and infrared thermography. Infrared thermography is more reliable than the others. Indirect blood flow-related indicators also include pulse oximetry, perfusion index, and pulse transit time. Pulse transit time can correlate cardiac ejection with peripheral oxygen, greatly enhancing the accuracy of monitoring indicators. Unlike indirect blood flow-related indicators, laser Doppler flowmetry and laser speckle flowmetry can directly provide detailed information on blood flow velocity and distribution. On the other hand, non-blood flow-related indicator skin conductance can reflect the excitatory state of the sympathetic nervous system, enable more accurate and rapid monitoring of blockade results. This article reviews various monitoring methods for the successful lumbar sympathetic ganglion blockade, with a focus on both direct blood flow-related and non-blood flow-related monitoring indicators, aiming to provide guidance for clinical selection.
