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Objectives-The purpose of this study was to determine the incidences and rates of progression of varying degrees of carotid stenosis that do not require intervention according to the Asymptomatic Carotid Atherosclerosis Study, the European Carotid Surgery Trial, and the North American Symptomatic Carotid Endarterectomy Trial, and from this information, to provide evidence-based recommendations for follow-up imaging.

The purpose of this study was to determine the incidences and rates of progression of varying degrees of carotid stenosis that do not require intervention according to the Asymptomatic Carotid Atherosclerosis Study, the European Carotid Surgery Trial, and the North American Symptomatic Carotid Endarterectomy Trial, and from this information, to provide evidence-based recommendations for follow-up imaging.A retrospective review was performed of all carotid ultrasound examinations performed at a single institution from January 1995 through April 2015. Examinations following endarterectomy or stenting were excluded. Stenoses were classified by a modification of the criteria of Bluth et al (Radiographics 1988; 8:487-506). A Kaplan-Meier survival analysis was performed for stenosis progression and to provide information for follow-up recommendations.Most of the carotid arteries (91.6%) reviewed for this study showed 1% to 39% stenosis. However, only 6.8% of carotid arteries with 1% to 39% stenosis progressed compared to 38.9% of carotid arteries with 40% to 59% stenosis. A table of evidence-based follow-up recommendations is provided for patients with varying levels of stenosis.We provide evidence-based follow-up recommendations for patients who have low degrees of carotid stenosis. Different degrees of carotid stenosis progress at different rates and therefore should be followed at different intervals. Additionally, the most patients in our database showed 1% to 39% stenosis and did not have any follow-up imaging, suggesting that carotid ultrasound may not be overused for low degrees of stenosis.

The anatomy of the pedicle is complex and three-dimensional; however, there are basic dimensions important for possible screw placement. There are relatively few studies examining the pedicle anatomy in children. This study was performed to evaluate the feasibility of pedicle screw placement in children aged 5-16, based on key anatomic dimensions. A case illustration is also provided.The CT scans of 102 consecutive children were studied. Patients with abnormal anatomy were excluded. The parameters of the pedicle isthmus width (W), estimation of screw length (L), and axial angle (A) were recorded for 1,632 pedicles from T10 through L5. Patients were divided into four age groups. Statistical analysis was performed evaluating the difference between males and females and of the particular anatomy at the thoracolumbar junction.The pedicles increase in both L and W from T10-T12 and from L1-L5. L1 has a consistently smaller W compared to T12 in both genders over all age ranges. Estimating a W of 4.5 mm necessary for safe screw placement, we calculate that virtually all pedicles of T12 and L3-L5 are large enough for screw placement in both genders after age 8. L4 and L5 are large enough for screw placement in both genders in the youngest age range.Most of the pedicles of the lower lumbar spine and T12 are large enough to house the smallest commercially available screw. Understanding of the anatomy at the thoracolumbar junction is important, as the W of L1 is consistently smaller than T12.