By V. Konrad. Greenville College. 2018.
Neuroimaging can deﬁne the anatomic location of the conus medullaris generic 3 mg stromectol mastercard, but "tethered" is a neurophysiologic concept that requires clinical input (12) generic stromectol 3mg on line. Five to six percent of normal individuals can have variable amounts of fat in the ﬁlum terminale (13,14). Epidemiology Spinal Dysraphism Three percent of neonates have major central nervous system or systemic malformations (15). Furthermore, 5% to 15% of pediatric neurology hospi- tal admissions are related to cerebrospinal anomalies (16). Occult spinal dys- raphism is the most prevalent spinal axis malformation (19) and the most common indication for spinal imaging in children (20). Occult spinal dys- raphic lesions are commonly associated with urinary tract anomalies (21). The clinical spectrum of occult dysraphism is broad, ranging from skin stigmata such as a dimple, sinus tract, hair patch, or hemangioma to motor, bladder, or bowel dysfunction (22–24). About 50% to 80% of occult spinal dysraphic cases exhibit a dermal lesion (25–28). Scoliosis Adolescent idiopathic scoliosis, by far the most common form, has a preva- lence between 0. In a United Kingdom study of 15,799 children and young adolescents, Stir- ling and colleagues (31) found that the prevalence ratio of girls to boys was 5. Infantile scoliosis constitutes approximately 8% of idio- pathic scoliosis whereas juvenile scoliosis represents 18% (34). Congenital scoliosis is caused by failure of segmentation of formation of spinal elements (4). In a series of 60 cases of congenital scoliosis, Shahcheraghi and Hobbi (6) found that the most common type of anomaly was a hemivertebra (failure of formation), and that the most severe deformity was associated with a unilateral unseg- mented bar (failure of segmentation) with a contralateral hemivertebra). Chapter 18 Imaging of Spine Disorders in Children 339 The etiology of adolescent scoliosis remains a mystery; however, some principles are generally agreed on (35): 1. The younger the onset and the greater the severity of the curve, the faster the progression. Although previously it was believed that scoliosis remained stable after skeletal maturity was attained, Weinstein and Ponseti (36) demonstrated that 68% of curves worsened after bone maturity.
Patients involved in high-energy trauma are commonly on backboards stromectol 3mg mastercard, have other injuries generic stromectol 3 mg with visa, and may be uncooperative. Cervical radiography in this group has been found to be more difﬁcult to perform adequately, resulting in lower speciﬁcity, and requiring longer time, more repeat radiographs, and higher costs (44,45). Radiograph speci- ﬁcity ranges from approximately 96% in patients with only minor noncer- vical injuries, to 89% in patients with head injury, to 78% in patients with head injury and a high-energy mechanism such as motorcycle crash (45). Radiographs are relatively inexpensive, with direct, short-term resource ranging from $34 to $60 (44). More recently, CT has been proposed as an initial cervical spine evalua- tion modality in patients who are victims of major trauma. Nuñez and col- leagues studied the use of CT in the initial evaluation of trauma patients and demonstrated high sensitivity for fracture (99%) in a large, level II prospective series (moderate evidence) (42). Also, CT demonstrated high speciﬁcity (93%), even in patients at high-risk of fracture (Table 17. Avey Direct, short-term resource costs of cervical spine CT likely exceed those of radiography, but no comprehensive cost analyses of CT have been pub- lished. Assessment of cost of cervical spine CT is difﬁcult as many institu- tions obtain economies of scale by performing CT of the cervical spine in the same setting as CT of the head (43,47). However, CT may be faster than radiography, and Nuñez and colleagues (42) have suggested that use of CT may decrease patient time in the emergency department. Therefore, CT has higher sensitivity and speciﬁcity for cervical spine fracture in high-risk patients, but at potentially higher cost. The appropriateness of CT as initial cervical spine imaging strategy in patients who are also undergoing head CT has been examined with cost- effectiveness analysis (43). This analysis, taken from the societal perspec- tive, was based on a decision-analysis model, and compared the cost effectiveness of radiography and CT for patients at different probabilities of cervical spine fracture. The cervical spine cost-effectiveness model, taken from the societal perspective, was dependent on radiograph sensitivity, radiograph speciﬁcity, CT sensitivity, CT speciﬁcity, probability of fracture, and the probability of paralysis or the likelihood that a patient will become paralyzed if a fracture was missed by cervical imaging. In addition, the cost-effectiveness model was dependent on the short-term resource cost of radiography and CT, as well as the cost of the imaging that was induced by the initial strategy, and the cost of any neurologic deﬁcit (paralysis) that developed from missed fracture. Costs were estimated from Medicare reimbursement data, and literature estimates, and the analysis was limited to adults (43).