Assessment of Intramedullary Spinal Pressure in Small Breed Dogs With Thoracolumbar Disk Extrusion Undergoing Hemilaminectomy

OBJECTIVE To assess intramedullary spinal pressure (IMP) in small breed dogs with thoracolumbar disk extrusion. STUDY DESIGN Prospective cohort study. ANIMALS Small breed dogs (n = 14) with thoracolumbar disk extrusion undergoing hemilaminectomy and healthy chondrodystrophic laboratory dogs (control; n = 3) without spinal disease. METHODS Diagnosis was based on clinical and neurological examinations and magnetic resonance imaging (MRI) and was confirmed intraoperatively. A standardized anesthesia protocol and surgical procedure were used to minimize factors that could influence IMP. Intramedullary pressure was measured through a minidurotomy at the site of spinal cord compression using a fiber optic catheter inserted perpendicular to the longitudinal axis of the spinal cord. Measurements were taken after hemilaminectomy and again after removal of extruded disk material. RESULTS Affected dogs had significantly higher IMP compared to control dogs (P = .008) and IMP decreased significantly post-decompression compared with initial values (P < .001). No correlation was found between IMP and neurologic grade, degree of spinal cord compression on MRI, or signal intensity changes on MRI. CONCLUSION Acute thoracolumbar disk extrusion is associated with increased IMP in small breed dogs and surgical decompression results in an immediate decrease of IMP.

A retrospective study of 1- versus 2-cm excision margins for cutaneous malignant melanomas thicker than 2 mm.

BACKGROUND Most guidelines recommend at least 2-cm excision margin for melanomas thicker than 2 mm. OBJECTIVE We evaluated whether 1- or 2-cm excision margins for melanoma (>2 mm) result in different outcomes. METHODS This is a retrospective cohort study on patients with melanomas (>2 mm) who underwent tumor excision with 1-cm (228 patients) or 2-cm (97 patients) margins to investigate presence of local recurrences, locoregional and distant metastases, and disease-free and overall survival. RESULTS In all, 325 patients with mean age of 61.84 years and Breslow thickness of 4.36 mm were considered for the study with a median follow-up of 1852 days (1995-2012). There was no significant difference in the frequency of locoregional and distant metastasis between the 2 groups (P = .311 and .571). The survival analysis showed no differences for disease-free (P = .800; hazard ratio 0.948; 95% confidence interval 0.627-1.433) and overall (P = .951; hazard ratio 1.018; 95% confidence interval 0.575-1.803) survival. LIMITATIONS The study was not prospectively randomized. CONCLUSIONS Our study did not show any significant differences in important outcome parameters such as local or distant metastases and overall survival. A prospective study testing 1- versus 2-cm excision margin is warranted.

A meta-analysis of trabecular bone score in fracture risk prediction and its relationship to FRAX

Trabecular bone score (TBS) is a grey-level textural index of bone microarchitecture derived from lumbar spine dual-energy X-ray absorptiometry (DXA) images. TBS is a BMD-independent predictor of fracture risk. The objective of this meta-analysis was to determine whether TBS predicted fracture risk independently of FRAX probability and to examine their combined performance by adjusting the FRAX probability for TBS. We utilized individual level data from 17,809 men and women in 14 prospective population-based cohorts. Baseline evaluation included TBS and the FRAX risk variables and outcomes during follow up (mean 6.7 years) comprised major osteoporotic fractures. The association between TBS, FRAX probabilities and the risk of fracture was examined using an extension of the Poisson regression model in each cohort and for each sex and expressed as the gradient of risk (GR; hazard ratio per 1SD change in risk variable in direction of increased risk). FRAX probabilities were adjusted for TBS using an adjustment factor derived from an independent cohort (the Manitoba Bone Density Cohort). Overall, the GR of TBS for major osteoporotic fracture was 1.44 (95% CI: 1.35-1.53) when adjusted for age and time since baseline and was similar in men and women (p > 0.10). When additionally adjusted for FRAX 10-year probability of major osteoporotic fracture, TBS remained a significant, independent predictor for fracture (GR 1.32, 95%CI: 1.24-1.41). The adjustment of FRAX probability for TBS resulted in a small increase in the GR (1.76, 95%CI: 1.65, 1.87 vs. 1.70, 95%CI: 1.60-1.81). A smaller change in GR for hip fracture was observed (FRAX hip fracture probability GR 2.25 vs. 2.22). TBS is a significant predictor of fracture risk independently of FRAX. The findings support the use of TBS as a potential adjustment for FRAX probability, though the impact of the adjustment remains to be determined in the context of clinical assessment guidelines. This article is protected by copyright. All rights reserved.