UHMWPE resin powder (GUR 1050, Ticona, USA) was mixed with Background
Materials & Methods
Electron-beam-irradiated Both pure UHMWPE and Vitamin E added (0.3% w/w) resin was used to produce bulk specimens via vacuum direct compression molding at 220°C under 25 MPa for 30 min. Cylindrical pins (3.5 mm diameter, 40 mm length) for ESR measurement were then machined and placed in vacuum packaging. The pins were irradiated at 300 kGy, with half of each test group annealed at 80°C for 24 hours. Free radical measurements were made using a high-sensitive X-band ESR operating at 9.44 GHz. Detection of Vitamin E radicals was performed by comparing the characteristic symmetrical spectrum of oxidized Vitamin E to the spectra observed for the pins using both g-value and linewidth as references. Crosslink density was measured via gel fraction analysis and was performed in accordance with ASTM D2765. Thin sections (20 × 40 mm2, 200 μm) were machined from the bulk specimens, which were then placed in vacuum packaging, irradiated and annealed at the same conditions as those for the ESR measurements. Two of these thin sections were then placed in a stainless-steel cage (200 µm pore diameter) and were immersed in decahydronaphtalene at 200°C for 24 hours. These specimens were then extracted using soxhlet extractor at 100°C for 24 hours and dried in vacuum at 150°C for 12 hours.INTRODUCTION
MATERIALS & METHODS
In February 2004, our institute began to perform routine cervical CT scans in addition to head CT examinations on patients with blunt head trauma who had received high energy injuries. We present the findings of 108 patients who underwent a routine cervical CT within the last year and the usefulness of routine cervical CT examinations is discussed. The present report is, to our knowledge, the only prospective study to examine the utility of routine cervical CT examinations. Among the patients admitted to the emergency room of our institute after receiving high energy injuries, 108 patients had blunt head trauma and underwent a routine cervical CT examination in addition to the head CT examination specified by our original protocol for cervical clearance. The mechanism of injury and the presence of cervical bone lesions were noted in each case. 76 males and 32 females ranging in age from 13 to 77 years (average, 41.0 years) were included in the study. Among these 108 cases, cervical fractures or subluxation were visible in 5 cases on plain films. Although no fractures were seen on the plain films taken in the remaining 103 cases, the additional cervical CT examinations demonstrated 14 cervical fractures in 13 (12.6%) of these cases. For patients with blunt head trauma, a cervical CT examination is not usually performed if no evidence of a cervical fracture is found on plain films and no neurological deficits are present. Nevertheless, the present findings suggest that many cervical fractures may have been missed on plain films in the past, and the routine inclusion of a cervical CT examination in addition to a head CT examination might be appropriate in the evaluation of patients with blunt head trauma who have been involved in a high energy injury.
