Study Design: A retrospective review of patients with ankylosing spondylitis involved in blunt trauma. Setting: Patients referred to two Level I trauma centers. Objectives: To determine the incidence and clinical sequelae in this patient population where vertebral injury was diagnosed on a delayed basis. Summary of Background Data: The ankylosed spine is at increased risk for fracture and spinal cord injury. Radiological identi®cation of injury is more di cult than in the normal spine. Results: Over a 5 year period, 21 patients were identi®ed with seven having an occult vertebral fracture not recognized as the primary injury or occurring as a second noncontiguous injury level. In these cases, delay in diagnosis of the occult injury was from 3 to 22 days. Development of secondary neurological de®cits occurred in three patients. Conclusions: A high index of suspicion and an appreciation of the extreme instability of a fracture in ankylosing spondylitis must be present.

We sought to determine if left ventricular (LV) function of the heart from the adult, chronically obese animal is impaired. Hearts from 50 wk-old genetically obese female Zucker rats (624 +/- 13 g) and their lean littermate controls (275 +/- 5 g) were isolated during ether anesthesia, supported metabolically by retrograde aortic perfusion (6 ml/min, 35 degrees C) with physiological solution containing suspended canine erythrocytes (hematocrit, 20%), and the ventricles were paced at 180 beats/min. A distensible, fluid-filled balloon was placed in the LV, and pressure-volume (PV) relationships were obtained. The obese and lean end-diastolic PV curves were not different, and therefore the obese and lean LV chamber compliances were similar. Comparison of the systolic PV relationships demonstrated that the obese rat's heart had a greater pressure-generating capability, which probably was a reflection of its increased LV mass (0.96 +/- 0.03 vs. 0.72 +/- 0.02 g). The calculated average meridional (or circumferential) peak systolic wall stress in the LV of the obese rat's heart, however, was significantly reduced compared with control. This diminished ability to develop systolic stress from the same end-diastolic volumes suggests that the hypertrophied LV of the middle-aged obese rat's heart is dilated or that its contractility is depressed, or both.

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Background: We aimed to identify preoperative predictors of survival in Metastatic Epidural Spinal Cord Compression (MESCC) patients surgically treated, examine how these predictors relate to eight prognostic models, and to perform the first full external validation of these models in accordance with the TRIPOD statement. Methods: 142 surgically treated MESCC patients were enrolled in a prospective, multicenter cohort study and followed for 12 months or until death. Cox proportional hazards (PH) regressions were used. Non-collinear predictors with <10% missing data, ≥10 events per stratum and p<0.05 in univariable analysis were tested through a backward stepwise selection. For the original and revised Tokuhashi, Tomita, modified Bauer, van der Linden, Bartels, OSRI, Bartels and Bollen, we examined calibration and discrimination; survival stratified by risk groups with the Kaplan-Meier method and log-rank test. Results: Primary tumor, organ metastasis and SF-36v2 PC were associated with survival in multivariable analysis; corrected discrimination was 0.68. These three predictors were common to most current prognostic models. However, calibration was poor overall while discrimation was possibly helpful. Conclusions: Primary tumor type (breast, prostate and thyroid), absence of organ metastasis, and a lower degree of physical disability are preoperative predictors of longer survival in surgical MESCC patients. Clinicians should use these 8 prognostic models with caution.