#235 Analysis of the Areolar Space between Great Vessels and Lumbar Spine
Image-Guidance, Navigation, Robotics
Poster Presented by: L. Pimenta
L. Pimenta (1), (2)
R. Jensen (2)
L. Marchi (2)
L. Oliveira (2)
C. Castro (2)
E. Coutinho (2)
T. Coutinho (2)
R. Amaral (2)
(1) UCSD, Neurosurgery, San Diego, CA, USA
(2) Instituto de Patologia da Coluna, Sao Paulo, Brazil
Purpose: Although there are published articles regarding the relationship between anterior lumbar spine surgery and abdominal great vessels, to the best of our knowledge, there are no studies regarding the space between these structures and the lumbar spine and its positioning, important data for lateral and posterior access. The purpose of this study is to evaluate the areolar space anteriorly to the lumbar spine and great vessels positioning.
Methods: Radiological study from seventy-four patients. T2-weighted axial and sagittal MRIs were studied. Specimens with deformities, such as scoliosis, kyphosis, or collapsed or herniated intervertebral discs were excluded from the study. Several measurements were made: total lumbar lordosis and level lordosis (sagittal MRI); disc diameter, space between disc and vessels, space between vertebrae and vessels, aortic bifurcation in relation to the lumbar spine level, iliac veins confluence in relation to the lumbar spine.
Results: Disc diameters gradually increased from L1-2 to L4-L5 (p< 0.01; L1-2 37±2.8mm; L2-3 39±3.4mm; L3-4 40±3.5mm; L4-5 41±4mm) as the lordosis value, (p< 0.001; L1-2 +0.9±.9°; L2-3 -3.8±4.7°; L3-4 -8.2±5.1°; L4-5 -19.5±6.7°). The aortic bifurcation was usually positioned immediately anterior to the body of the L4 (61%) vertebra and less frequently at the L3-4 (19%) and L4-5 (17%) disc spaces. The iliac veins confluence was usually positioned immediately anterior to the L4-5 disc (44%) and at the L5 vertebra (33%), and less frequently at the L4 vertebra (17%). Disc AP diameter were greater than its adjacent vertebral bodies (p< 0.001) and this reflects the closer distance of vessels to the discs over to the vertebral bodies (p< 0.001). The areolar space to the iliac vein increases in the cranial direction (p< 0.001; L4L5 0.7mm; L3L4 1.6mm; L2L3 3.9mm; L1L2 11mm), while to the aorta it remains almost the same (p=0.7; L4L5 1.9 mm; L3L4 1.8mm; L2L3 2.1mm; L1L2 1.4mm).
Conclusions: Close relation of great vessels and the lumbar discs are found especially in the L4-L5 spine level, which is the wider disc in AP diameter and possesses great lordosis among lumbar levels. Anterior annulus and ALL should be retained for a safe L4-L5 discectomy. Precaution and full investigation of the anatomical position of the vessels might be required before surgery is performed.