Intra- and interrater reliabilities and a method comparison of 2D and 3D techniques in cadavers to determine sacroiliac screw loosening

New method to apply the lumbar lordosis of standing radiographs to supine CT-based virtual 3D lumbar spine models

Standing radiographs play an important role in the characterization of spinal sagittal alignment, as they depict the spine under physiologic loading conditions. However, there is no commonly available method to apply the lumbar lordosis of standing radiographs to supine CT-based virtual 3D models of the lumbar spine. We aimed to develop a method for the sagittal rigid-body registration of vertebrae to standing radiographs, using the exact geometry reconstructed from CT-data. In a cohort of 50 patients with monosegmental spinal degeneration, segmentation and registration of the lumbar vertebrae and sacrum were performed by two independent investigators. Intersegmental angles and lumbar lordosis were measured both in CT scans and radiographs. Vertebrae were registered using the X-ray module of Materialise Mimics software. Postregistrational midsagittal sections were constructed of the sagittal midplane sections of the registered 3D lumbar spine geometries. Mean Hausdorff distance was measured between corresponding registered vertebral geometries. The registration process minimized the difference between the X-rays' and postregistrational midsagittal sections' lordoses. Intra- and inter-rater reliability was excellent based on angle and mean Hausdorff distance measurements. We propose an accessible, accurate, and reproducible method for creating patient-specific 3D geometries of the lumbar spine that accurately represent spinal sagittal alignment in the standing position.

The topography and morphometrics of the pubic ligaments

BACKGROUND

Conflicting anatomical reports and the little attention given to the pubic ligaments impede the interpretation of radiological and clinical examinations on groin pain. Morphometric data on the pubic ligaments are lacking.

METHODS

The muscular relations of the symphysis pubis were examined in layered dissection (n = 10), hemipelves (n = 60) and (un)stained plastinated body slices of body donors (n = 3). The sagittal and coronal areas, width, mean and maximum thickness of pubic ligaments were determined.

RESULTS

The adductor longus, brevis, rectus abdominis and pyramidalis muscles are attached to the anterior pubic ligament (APL). The adductor brevis and gracilis muscle are connected to the inferior pubic ligament (IPL). The IPL and superior pubic ligament (SPL) are thicker than the APL and posterior pubic ligament (PPL). The PPL is the thinnest pubic ligament. The APL has a larger sagittal area in women than in men compared to the IPL. The SPL and IPL are thicker in men compared to women.

CONCLUSION

The APL is the ligamentous anchor for the originating and inserting muscles. Investigations of the pubic ligaments might help to determine symphysis instability or severity of injury and should be included as a further criterion for surgical management.