Trabecular architecture of lumbar vertebral pedicle.

Study Design: Investigation on architecture of lumbar pedicle.

Objective: To determine morphological properties of pedicular cancellous bone.

Summary Of Background Data: Many researchers have been stimulated to study trabecular architecture by improvements in stereological technology. Although the structure of vertebral cancellous bone has been well studied in the literature, no information is available about the architecture of pedicular cancellous bone.

Methods: Eight cadaveric L3 lumbar vertebrae were harvested. After collecting the bone mineral density (BMD) data on the vertebrae, pedicle isthmuses were removed from the vertebral bodies using a reciprocal hand saw. The BMD measurements were done on the dissected pedicle isthmus specimens. All the specimens were then analyzed using a micro-computed tomography unit. Morphologic parameters of trabecular bone were calculated.

Results: Bone volume was found as 0.209 +/- 0.046, whereas Tb.Th, Tb.Sp, and Tb.N were found to be 0.201 +/- 0.035 mm, 0.930 +/- 0.123 mm, and 1.098 +/- 0.136 mm(-1), respectively. Connectivity density and structure model index were observed to be 3.135 +/- 0.918 mm(-3), 0.37, whereas degree of anisotropy value was 1.241 +/- 0.093. Vertebral BMD could explain 63% of variance in bone density of a pedicle isthmus.

Conclusions: The structure of the pedicular cancellous bone is somewhat different from that of vertebral body. The trabecular architecture within the pedicle isthmus is isotropic and plate-like. The thickness and number of the trabeculae were greater than those of vertebral trabeculae. Decrease in the bone volume with age is mainly by thinning of the trabeculae and increasing in trabecular spacing, but not by loss of mass.