Anatomical Relationships of the Anterior Blood Vessels to the Lower Lumbar Intervertebral Discs Analysis Based on Magnetic Resonance Imaging of Patients in the Prone Position
ABSTRACT Intra-abdominal vascular injuries are rare during posterior lumbar spinal surgery, but they can result in major morbidity or mortality when they do occur. We are aware of no prior studies that have used prone patient positioning during magnetic resonance imaging for the purpose of characterizing the retroperitoneal iliac vasculature with respect to the intervertebral disc. The purpose of this study was to define the vascular anatomy adjacent to the lower lumbar spine with use of supine and prone magnetic resonance imaging.
A prospective observational study included thirty patients without spinal abnormality who underwent supine and prone magnetic resonance imaging without abdominal compression. The spinal levels of the aortic bifurcation and confluence of the common iliac veins were identified. The proximity of the anterior iliac vessels to the anterior and posterior aspects of the anulus fibrosus in sagittal and coronal planes was measured by two observers, and interobserver reliability was calculated.
The aortic bifurcation and confluence of the common iliac veins were most commonly at the level of the L4 vertebral body and migrated cranially with prone positioning. The common iliac vessels were closer to the anterior aspect of the intervertebral disc and to the midline at L4-L5 as compared with L5-S1, consistent with the bifurcation at the L4 vertebral body. Prone positioning resulted in greater distances between the disc and iliac vessels at L4-L5 and L5-S1 by an average of 3 mm. The position of the anterior aspect of the anulus with respect to each iliac vessel demonstrated substantial variation between subjects. The intraclass correlation coefficient for measurement of vessel position exceeded 0.9, demonstrating excellent interobserver reliability.
This study confirmed the L4 level of the aortic bifurcation and iliac vein coalescence but also demonstrated substantial mobility of the great vessels with positioning. Supine magnetic resonance imaging will underestimate the proximity of the vessels to the intervertebral disc. Large interindividual variation in the location of vasculature was noted, emphasizing the importance of careful study of the location of the retroperitoneal vessels on a case-by-case basis.
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ABSTRACT: An in vivo anatomic study analyzing the venous anatomy in the lumbosacral area was performed. To obtain in vivo data concerning iliocava junction and left common iliac vein positions at L5-S1. The left common iliac vein and the iliocava junction are at risk during L5-S1 anterior lumbar interbody fusion. Anatomic studies have demonstrated great interindividual variability in this vascular anatomy. Magnetic resonance angiography was used to study 134 patients. Image processing was carried out with maximum intensity projection algorithm and the maximum intensity projection and addition algorithm. Iliocava junction position was measured in the maximum intensity projection and addition image. Four groups of junction position were established: very high, high, low, and very low. The left common iliac vein position was measured in axial magnetic resonance images, and three groups were established: lateral, intermediate, and medial. To describe the operative window delimited by the venous structures at L5-S1, the study population was classified into 12 configurations by combining junction position and vein position values. Very high lateral included 3.76% of the patients, high lateral 48.12%, high intermediate 10.53%, high medial 0.75%, low lateral 15.04%, low intermediate 4.51%, low medial 6.77%, very low lateral 0.75%, very low intermediate 2.26%, and very low medial 7.52%. Medial vein position was significantly more frequent in men. In 18.05% of the study population, the venous structures overlapped the center of the L5-S1 disc, reducing the operative window.Spine 08/2000; 25(13):1695-700. DOI:10.1097/00007632-200007010-00013 · 2.45 Impact Factor
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ABSTRACT: Vascular complications related to lumbar disc operations are rare but extremely fatal conditions. The authors analyzed data retrospectively obtained in 13 patients with vascular complications that occurred during lumbar disc operations performed between January 1990 and January 2002. One patient underwent an L5-S1 procedure and the remaining underwent L4-5 surgery. Missed injuries, which were found during the late postoperative period, included pseudoaneurysm in four cases and an arteriovenous fistula in one. In all cases except one in which complication occurred early in the postoperative period, the retroperitoneal area was reached via a transperitoneal approach. In eight patients with complications occurring early in the postoperative period. Dacron graft was placed in four with arterial injuries and saphenous vein graft in one. In three cases of arterial injury and five of venous injury, the lesion was repaired using the primer suture technique. The most commonly affected vessels were left common iliac arteries (76.9%) and left common iliac vein (30.8%). In eight early cases, shock or preshock due to hemorrhage developed during the early phase. During the late postoperative period, graft-related infection occurred in two cases in which Dacron graft was placed, and axillofemoral extraanatomical bypass surgery was later performed. There was no surgery-related death. During a mean follow-up period of 5.6 years, none of the patients suffered any problems related to vascular injury. Despite its low incidence, iatrogenic vascular injury related to lumbar disc surgery is a possible complication. During lumbar disc operations early diagnosis of vascular injuries and urgent transperitoneal surgery can save patients' lives.Journal of Neurosurgery 04/2004; 100(3 Suppl Spine):249-53. DOI:10.3171/spi.2004.100.3.0249 · 3.23 Impact Factor
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ABSTRACT: The objective of this study was to determine the level of the aortic bifurcation in relation to the lumbar spine by MRI and the effect of lumbosacral anomalies on the aortic bifurcation. A prospective study of 441 patients was performed. Sagittal MR images of the entire spine were obtained along with the standard protocol for imaging of the lumbar spine. The vertebrae were counted caudally from C2 instead of cranially from the presumed L5 vertebra. The aortic bifurcation in relation to the lumbar vertebrae was determined. The aorta bifurcated at the L4 vertebral body in 67% of cases. In patients with sacralization of L5 the aortic bifurcation was at the L3 vertebral body in 59%. In those patients with lumbarization of S1 the aorta bifurcated at the level of the L4 vertebral body in 40% and at the L4/5 disc space in 33%. There was no demographic variation of the aortic bifurcation in relation to age or sex. The aorta bifurcated at L4 in two-thirds of cases and was variably located in the remaining third. The stability of this as a landmark is disturbed by the significant high incidence of lumbosacral transitional segments.Surgical and Radiologic Anatomy 01/2003; 24(5):308-12. DOI:10.1007/s00276-002-0036-3 · 1.33 Impact Factor