309 - Increased Arterial Diameter and Blood Flow Following Lumbar Sympathetic Block: A Case Report

Case Diagnosis: Painful Lower Extremity Neuropathy

Case Description: A case study utilizing a lumbar sympathetic block (LSB) was performed on a patient with chronic paresthesia and neuropathic symptoms of the left foot refractory to treatment. Ultrasound, capillary refill, and temperature were also used to explore the effect of LSB on arterial dilation and blood flow to further examine a proposed mechanism of therapeutic benefit.

Discussions: Following LSB the patient experienced decreased pain, paresthesia, an increase in sensation, and observed erythema in the symptomatic foot approximately 45 minutes post LSB. Significant dilation of the posterior tibial artery (PTA) was observed following the LSB via ultrasound. Prior to LSB, PTA measured .17cm in diameter before dilating to .26cm in diameter following the LSB. Arterial blood flow velocity measured via doppler 65.1 cm/s pre-block and 57.4 cm/s 30 minutes post-block. Capillary refill was measured at x̅ 3.92 seconds pre-block and x̅ 1.30 seconds immediately post-block. Temperature of the foot was measured at 34.4 degrees Celsius pre-block and increased to 37.2 degrees Celsius 90 minutes post-block.

Conclusions: LSB have long been used for the treatment of chronic lower extremity pain and for conditions such Complex Regional Pain Syndrome. However, with better understanding of the autonomic nervous system and its function these blocks have grown in their utility. This case explores the potential mechanism of the therapeutic benefit of LSB by showing a significant dilation of the PTA and increased blood flow following LSB. This study examines both the clinical application and will also be the first known reported study to quantify arterial dilation and blood flow following LSB.