Anthropometric approach to lumbar vertebral body volumes

A novel method to estimate adult age from the lumbar vertebral body using 3D PMCT images in Japanese

This study evaluated the age-related changes in the vertebral body using 3D Postmortem CT (PMCT) images and proposed an alternative age estimation formula. The PMCT images of 200 deceased individuals aged 25 to 99 years (126 males, 74 females) were retrospectively reviewed and included in the study. Using the open-source software ITK-SNAP and MeshLab, a 3D surface mesh of the fourth lumbar vertebral body (L4) and its convex hull models were created from the PMCT data. Using their inbuilt tools, volumes (in mm3) of the L4 surface mesh and convex hull models were subsequently computed. We derived VD, defined as the difference in volumes between the convex hull and L4 surface mesh normalized by L4 mesh volume, and VR, defined as the ratio of L4 mesh volume to convex hull volume based on individual L4. Correlation and regression analyses were performed between VD, VR, and chronological age. A statistically significant positive correlation (P < 0.001) between chronological age and VD, (r_s = 0.764, males; r_s = 0.725, females), and a significant negative correlation between chronological age and VR (r_s = -0.764, males; r_s = -0.725, females) was obtained in both sexes. The lowest standard error of the estimate was demonstrated by the VR at 11.9 years and 12.5 years for males and females, respectively. As such, their regression models to estimate adult age were Age = 248.9-2.5VR years, males; Age = 258.1-2.5VR years, females. These regression equations may be useful for estimating age in Japanese adults in forensic settings.

Advanced Quantitative Spine Imaging

Although advanced quantitative imaging may not be currently used to any degree in the routine reporting of spinal examinations, this situation will change in the not too distant future. Advanced quantitative imaging has already allowed us to understand a great deal more regarding spinal development, marrow physiology, and disease pathogenesis. Radiologists are ideally suited to drive this research forward. To speed up this process and optimize the impact of studies reporting spine quantitative data, we should work toward universal standards on the acquisition of spine data that will allow quantitative studies to be more easily compared, contrasted, and amalgamated.

The spontaneous restoration of the course of psoas muscles after corrective surgery for adult spinal deformity

BACKGROUND

A previous study demonstrated that spinopelvic alignment and morphology influence a deviation in the course of psoas muscle (PM). However, it is unknown whether such deviations might be caused by a decrease in lumbar lordosis (LL) or the lateral deviation of the lumbar spine following scoliosis. The purpose of this study was to elucidate the close relationship between the coronal and sagittal lumbar alignment and a deviation in the course of PM.

METHODS

We investigated the preoperative and postoperative spinopelvic parameters and the morphology of PM at L4/5 level in 30 patients treated with corrective surgery for adult spinal deformity who were diagnosed with "rising psoas sign" before surgery. Spinopelvic parameters were measured on X-ray films. Investigation of the morphology of PM and the morphological measurements were performed using computed tomography (CT) images. The "rising psoas sign" was classified as bilateral- or unilateral-type as defined in the previous study.

RESULTS

Among 18 patients who had bilateral-type rising psoas sign before surgery, 11 patients remained bilateral-type after surgery despite an increase in LL. The pelvic incidence of these 11 patients was significantly larger than that of the other 7 patients (53.5 ± 10.2° vs 43.2 ± 5.8°) (p = 0.037). The magnitude of postoperative increase in LL positively correlated with that of the posterior shift of PM (r = 0.41, p = 0.025). The degree of restoration of the lumbar spine following scoliosis was positively correlated with that of the medial shift of PM (r = 0.66, p = 0.025).

CONCLUSION

The decrease in LL and the lateral deviation of lumbar spine following scoliosis caused a deviated course of the PM, which was spontaneously corrected by the restoration of lumbar alignment. However, the bilateral-type deviation in patients with higher pelvic incidence was considered to be within the range of normal variation.

Influence of spinopelvic alignment and morphology on deviation in the course of the psoas major muscle

BACKGROUND

In some people, the psoas major rises laterally or anteriorly at the L4/5 disc level and detaches from the most posterior aspect of the disc despite the absence of transitional vertebrae; this is called the "rising psoas sign." There are no reports of the relationship between spinopelvic parameters and rising psoas sign. The objective of this study was to investigate the relationship between spinopelvic parameters and deviations in the location and shape of psoas major muscle at the L4/5 disc level.

METHODS

We investigated the preoperative location and shape of both psoas major muscles in 64 patients treated with lateral lumbar interbody fusion. Spinopelvic parameters were measured on X-ray films. The morphology of psoas major at the L4/5 disc level was investigated with magnetic resonance images. The morphological measurements were normalized by the anteroposterior diameter of the center of the L4 vertebral body, which was measured by computed tomography. The rising psoas sign was classified into 2 types: bilateral or unilateral.

RESULTS

The pelvic incidence (PI) was significantly larger for the bilateral type than the others (normal and unilateral types) (60.2 ± 11.0 vs. 46.7 ± 8.7, p < 0.001). The PI correlated significantly with the normalized anteroposterior diameter of the pelvis (R = 0.66, p < 0.001). The receiver-operator characteristic curve showed an optimal cutoff value of PI = 54, with 75% sensitivity and 78.5% specificity. The coronal L1-4 Cobb angle was significantly larger in the unilateral type than the others (normal and bilateral types) (p < 0.0001). In the unilateral type, the Cobb angle in the recumbent position correlated significantly with the normalized distance of the lateral deviation of psoas major (R = 0.60, p = 0.0085).

CONCLUSION

The rising psoas sign was related to a higher PI and lumbar scoliosis. It was firstly elucidated that the spinopelvic alignment and morphology influence the deviation of the course of the psoas major muscle.

STUDY DESIGN

A retrospective morphological study.