Fellows’ Journal Club

Ninety-four flat panel catheter angiotomography acquisitions obtained during the selective injection of intersegmental arteries providing an anterior radiculomedullary artery were reviewed. The location of radicular arteries could be ascertained in 78/94 flat panel catheter angiotomography acquisitions. Fifty-three acquisitions (67.9%) were on the left side, and 25 (32.1%), on the right, between T2 and L3. The arteries were found in the anterosuperior quadrant in 75 cases (96.2%), in the posterosuperior quadrant in 2 (2.6%), and in the anteroinferior quadrant in 1(1.3%). Needle placement in the anterosuperior quadrant (subpedicular approach) should be avoided during transforaminal epidural steroid injection. The authors advocate the posterolateral approach that allows placing the needle tip away from the documented position of ARMA contributors within the neural foramen, reducing the risk of intra-arterial injection or injury to the spinal vascularization.

Abstract

Figure 2 from paper — Depiction of the arterial anatomy of the NF showing the measurements used in this study. A, Illustration of ISA anatomy including the principal supply to the thoracolumbar spinal cord from an anterior oblique view. The ISA originates from the aorta and divides into medial, dorsal, and lateral branches. A complete spinal branch is shown entering the NF at the left L1 vertebral level and providing a retrocorporeal artery, a prelaminar artery, and a radicular artery; the latter crosses the dura to continue as an ARMA and anastomoses with the anterior spinal artery. The shaded regions and quadrant grids depicted at the L1 NF clarify the working projection and measurement definitions depicted in B and C. B, FPCA, left L1 ISA injection, sagittal reconstruction (thickness = 0.2 mm) demonstrates the working projection used to take measurements. The image documents the location of an ARMA within the NF (*red arrow*) in a 59-year-old women investigated for acute onset paraplegia. Spinal angiography and FPCA revealed severe stenosis of the left proximal L1 ISA, resulting in an episode of spinal cord ischemia. Measurements were performed with the anterior surface to the left side. C, Measurements included the NF height (B to B′), which was defined as the long axis from the posterior edge of the vertebral pedicle to the superior edge of the pedicle below. The NF was divided into quadrants by measuring the width (C to C′) at the midpoint of the height. The ARMA location was evaluated by measuring the distance from the center of the artery to the superior (D) and anterior (E) walls of the NF and the vertical (F) and horizontal (G) distances to the quadrant divisions. ASQ indicates anterosuperior quadrant; PSQ, posterosuperior quadrant; PIQ, posteroinferior quadrant; AIQ, anteroinferior quadrant. Copyright 2016 Lydia Gregg.

BACKGROUND AND PURPOSE

Flat panel catheter angiotomography performed during the selective injection of intersegmental arteries offers a multiplanar assessment of the intraforaminal course of the radicular arteries providing an anterior radiculomedullary artery. Injury of anterior radiculomedullary arteries during transforaminal epidural steroid injections can result in spinal cord damage. Evaluations of the intraforaminal location of these arteries have so far been limited to anteroposterior views or the examination of cadaveric material. This study documents the in vivo intraforaminal location of thoracolumbar arteries providing an anterior radiculomedullary artery with flat panel catheter angiotomography.

MATERIALS AND METHODS

Ninety-four flat panel catheter angiotomography acquisitions obtained during the selective injection of intersegmental arteries providing an anterior radiculomedullary artery were reviewed. Measurements obtained from sagittal reconstructions were converted into a scatterplot visualization. Patients’ age, sex, and side and level of the injection were recorded.

RESULTS

The location of radicular arteries could be ascertained in 78 of 94 flat panel catheter angiotomography acquisitions (33 women and 45 men, 22–82 years of age). Fifty-three acquisitions (67.9%) were on the left side, and 25 (32.1%), on the right, between T2 and L3. The arteries were found in the anterosuperior quadrant of the neural foramen in 75 cases (96.2%), in the posterosuperior quadrant in 2 cases (2.6%), and in the anteroinferior quadrant in 1 case (1.3%). None were located in the posteroinferior quadrant. No differences in location were observed with age, sex, side of injection, or vertebral level.

CONCLUSIONS

Avoiding needle placement in the superior half of the neural foramen, specifically the anterosuperior quadrant, can reduce the risk of spinal cord injury during transforaminal epidural steroid injection.

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Intraforaminal Location of Thoracolumbar Radicular Arteries Providing an Anterior Radiculomedullary Artery Using Flat Panel Catheter Angiotomography

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