Magnetic resonance morphometry of the adult normal lumbar intervertebral space.

PURPOSE: This study aims to: (a) quantify and evaluate normal relationships between neighboring spinal units using MR imaging indices, (b) propose an easy-to-apply-and-reproduce method of estimating the correct amount of distraction when surgically restoring a collapsed intervertebral disc, based on individualized measurements. METHODS: This is a retrospective cross-sectional MR imaging study of 119 adult subjects, aged 18-54, asymptomatic for low back pain. Each of the examinees should demonstrate two or more consecutive intervertebral discs classified as Pfirrmann grade I or II to be included. We measured and studied the relationships of disc height index, Dabbs index, Farfan index, disc convexity index and mean and posterior disc height per spinal level using multiple regression analysis. All measurements were tested for intra- and interobserver agreement by two raters. RESULTS: DHI, Dabbs, Farfan, and mean disc height had a statistically significant correlation with the spinal level and age. Our results were highly reproducible, with excellent inter- and intraobserver agreement and reliability between two raters (ICC = 0.992 and 0.994, respectively). Furthermore, we expressed each intervertebral space as a percentage of its adjacent space, introducing the coefficient α factor for every intervertebral space. CONCLUSIONS: Our results suggest that a normal values' database to refer during preoperative planning of correction of a degenerated intervertebral disc is feasible. Our study offers new anatomical and radiological insight in terms of spinal measurements and their potential correlation with current surgical techniques. A new approach for calculating disc space as an expression of its adjacent disc has been introduced with various potential applications.

Detection of O-Linked-N-Acetylglucosamine Modification and Its Associated Enzymes in Human Degenerated Intervertebral Discs.

STUDY DESIGN: Human herniated discs were obtained from discectomy specimens for the immunohistochemical detection of O-GlcNAc and O-GlcNAcase (OGA)/O-GlcNAc transferase (OGT). PURPOSE: This study aimed to quantify the extent of O-GlcNAcylation and its associated enzymes (OGT/OGA) in human degenerated intervertebral discs. OVERVIEW OF LITERATURE: The O-GlcNAcylation of nuclear, cytoplasmic, and mitochondrial proteins as well as the effects of such post-translational modifications are currently the focus of extensive research. O-GlcNAcylation is believed to contribute to the etiology of chronic illnesses by acting as a nutrient and stress sensor in the cellular environment. Mature intervertebral disc cells are chondrocyte-like cells, and O-GlcNAc has been shown to promote chondrocyte apoptosis in vitro. We believe that O-GlcNAcylation is a key regulator of disc degeneration. METHODS: Fifty-six specimens were fixed for 24 hours in a 10% solution of neutral-buffered formaldehyde, dehydrated, and embedded in paraffin. Tissue slices (4-µm-thick) were used for hematoxylin-eosin staining and immunohistochemistry. RESULTS: We found that O-GlcNAcylation of cytoplasmic proteins was less than that of nuclear proteins in both single cells and cell clusters. Cytoplasmic O-GlcNAcylation occurs subsequent to nuclear O-GlcNAcylation and is directly proportional to disc degeneration. OGT and O-GlcNAc expression levels were identical in all specimens examined. CONCLUSIONS: O-GlcNAc and OGA/OGT expression is shown to correlate for the first time with intervertebral disc cell degeneration. Increasing disc degeneration is associated with increasing O-GlcNAcylation in both nuclear and cytoplasmic proteins in human disc cells.

Quadratus femoris tear as an unusual cause of hip pain: a case report.

PURPOSE: To show that quadratus femoris muscle partial or complete tear is an extremely rare if not underdiagnosed cause of hip pain. METHODS: We present the case of a 75-year-old Caucasian woman with spontaneous non-traumatic quadratus femoris tear. RESULTS: Computed Tomography showed quadratus femoris tear with occult underlying ischiofemoral impingement pathology. CONCLUSIONS: Quadratus femoris muscle is a hip external rotator and adductor and is situated along the posterior aspect of the hip joint and its proximity of anatomy with other external rotators leads to diagnostic pitfalls for radiologists. Identification of the exact muscle tear will establish the diagnosis, guide the proper physical therapy and reliably inform the patient what to expect after treatment.