Novel developments in MR angiography are reviewed that enable non-invasive clinical imaging of normal and abnormal vessels of the spinal cord. Current fast contrast-enhanced MR techniques are able 1) to visualize vessels supplying or draining the spinal cord and 2) to differentiate spinal cord arteries from veins. The localization of the Adamkiewicz artery, the largest artery supplying the thoracolumbar spinal cord, has become possible in a reproducible and reliable manner. Knowledge of the anatomic location of this artery and its arterial supplier may be of benefit in the work-up for aortic aneurysm surgery to reduce incidences of ischemic injury. Spinal cord MR angiography is ready to become a diagnostic tool that can compete with catheter angiography for detecting and localizing arterial feeders of vascular lesions and is strongly advised for use prior to invasive catheter angiography. Successful clinical application strongly relies on in depth knowledge of the complex spinal cord vasculature and skills in image postprocessing.
El embolismo emergiendo como una de las principales causas de lesión de la médula espinal después de la reparación aórtica descendente y toracoabdominal con un enfoque contemporáneo: hallazgos en resonancia magnética de lesiones de la médula espinal.
Embolism is emerging as a major cause of spinal cord injury after descending and thoracoabdominal aortic repair with a contemporary approach: magnetic resonance findings of spinal cord injury.
OBJECTIVES: We reviewed magnetic resonance (MR) findings of the spinal cord in patients who had a spinal cord injury after descending and thoracoabdominal aortic repair, to speculate the specific cause of the injury. METHODS: Between 2000 and 2012, 746 patients underwent descending or thoracoabdominal aortic surgery: 480 received an open repair with adjuncts of spinal cord protection [distal perfusion, cerebrospinal fluid (CSF) drainage, reattachment of intercostal arteries and hypothermia] and 266 received an endovascular repair. Twenty-six (3.5%) suffered a spinal cord injury. Of these, 18 (14 open repair and 4 endovascular repair) underwent postoperative spinal cord MRI. Preoperative identification of the Adamkiewicz artery (ARM) was obtained in all patients except 1. Aortic pathology was dissection in 2 and non-dissection in 16 patients. RESULTS: There were 3 types MRI finding: sporadic infarction involving a range of spinal cord (sporadic); focal and asymmetrical infarction within a few segments of vertebra (focal); and diffuse and symmetrical infarction around the level of the ARM (diffuse). In endovascular repair, sporadic infarction was observed in all patients (4 of 4). In open repair, sporadic infarction was observed in 3 (21%), focal infarction in 7 (50%) and diffuse infarction in 4 (29%). In all patients who had sporadic or focal infarction, the aortic pathology was non-dissection. CONCLUSIONS: From these findings, embolism is 1 of the major causes of spinal cord injury in the era of adjuncts to optimize spinal cord haemodynamics during aortic repair.
Pain Med. 2013 Jun;14(6):808-12. doi: 10.1111/pme.12056. Epub 2013 Feb 25.
BACKGROUND: Transforaminal epidural steroid injection (TFESI) is a widely utilized interventional pain technique for radicular pain. Although the six o'clock position of the pedicle in the so-called "safe triangle" has been used as a target location, there have been a number of reported catastrophic complications of this procedure, including paraplegia. The mechanism of this has been attributed to the intravascular injection of steroids. The goal of this study was to examine the intraforaminal location of thoracolumbar medullary arteries which would help guide pain physicians in developing safer techniques and guidelines. METHODS: Twenty-four (24) embalmed cadavers were dissected and examined for the presence and distribution of thoracolumbar anterior medullary arteries. Access to the anterior surface of the spinal cord was made via anterior corpectomy from C2 to S5. Each medullary artery's course was determined by dissection from its origin, the anterior spinal artery, through the intervertebral foramen. The foramen was subsequently opened in the coronal plane, and the intraforaminal location of the artery, its diameter, and its relation to other foraminal structures were examined and measured. RESULTS: In the thoracolumbar foramina (T4-L2), 39 anterior medullary arteries were found, including 23 great medullary arteries (Adamkiewicz artery). One Adamkiewicz artery was found to be located in the left S2 foramen and was not included in the statistical analysis. Of the analyzed 39 anterior medullary arteries, 29 (74%) were located in the upper 1/3 of the foramen, 9 (23%) were located in the middle, and 1 (3%) artery was located in the lower 1/3. In relation to the dorsal root ganglion--ventral root complex, 21 (54%) arteries were located anterosuperiorly, 16 (41%) anteriorly, and 2 (5%) anteroinferiorly. The average intraforaminal artery diameter was 1.20 mm (0.84-1.91 mm). At thoracolumbar levels, theartery is almost always (92% ± 15%) located anterosuperior to the nerve. At typical thoracic levels, it is less often anterosuperior (38% ± 19%), but more often anterior to the nerve. CONCLUSIONS: At thoracolumbar levels, if needles were to encounter an artery, they are most likely to do so if placed anterosuperior to the nerve. Encountering an artery anterosuperior to the nerve is less likely at typical thoracic levels, but the likelihood is far from negligible. Pain physicians should be cognizant of this when considering optimal needle placement during transforaminal epidural steroid injections.