Significant spinal injury resulting from low-level accelerations: a case series of roller coaster injuries

OBJECTIVES: To describe a cohort of significantly injured roller coaster riders and the likely levels of acceleration at which the injuries occurred, and to compare these data with contemporary efforts to define a lower limit of acceleration below which no significant spinal injury is likely to occur. DESIGN: A retrospective case series of roller coaster ride-induced significant spinal injuries. SETTING: Injury incident records and emergency medical service records for the Rattler roller coaster in San Antonio, TX, were evaluated for a 19-month period in 1992 and 1993. Medical records for the more significant injuries were also reviewed and the specific injuries were tabulated, along with the demographics of the cohort. PARTICIPANTS: There were 932,000 riders of the Rattler roller coaster, estimated to represent between 300,000 and 600,000 individual riders. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Injury incident reports and medical record review. RESULTS: It is estimated that there were a total of 656 neck and back injuries during the study period, and 39 were considered significant by the study inclusion criteria. Seventy-two percent (28/39) of the injured subjects sustained a cervical disk injury; 71% of these injuries were at C5-6 (15 disk herniations, 5 symptomatic disk bulges) and 54% were at C6-7 (11 disk herniations, 4 symptomatic disk bulges). In the lumbar spine, the most frequent injury was a symptomatic disk bulge (20% of the cohort), followed by vertebral body compression fracture (18%), and L4-5 or L5-S1 disk herniation (13%). Accelerometry testing of passengers and train cars indicated a peak of 4.5 to 5g of vertical or axial acceleration and 1.5g of lateral acceleration over approximately 100ms (0.1s) on both. CONCLUSIONS: The results of this study suggest that there is no established minimum threshold of significant spine injury. The greatest explanation for injury from traumatic loading of the spine is individual susceptibility to injury, an unpredictable variable.     

Descending necrotizing mediastinitis: treatment by transcervical thoracic drainage

We report the case of a 29-year-old man with descending necrotizing mediastinitis and subcarinal spread secondary to oropharyngeal infection. The thoracic infection was treated by placement of a transcervical thoracic drain, which was removed 15 days after surgery. The outcome was satisfactory and no further invasive treatment was required. We believe that transcervical thoracic drainage is a useful initial treatment for descending necrotizing mediastinitis with subcarinal spread but no pleural cavity involvement.     

A nomogram for assessment of breathing patterns during treadmill exercise

Objective: To assess the breathing patterns of trained athletes under different conditions. The hypothesis is that the breathing pattern during a progressive treadmill exercise is independent of the protocol, at least in healthy people, and can be assessed using a nomogram.

Methods: A total of 43 male and 21 female athletes from different sports were studied. They performed one of two different protocols (steps or ramp) on a treadmill. The two protocols started at the same speed and had the same rate of increase in work. During the test, the expired air was analysed for CO₂ and O₂. Ventilation (VE) was continuously recorded, and tidal volume (Vt) and breathing frequency (BF) at the same intensity were analysed for both protocols, as well as Vt/T_i and T_i/T_tot.

Results: No significant differences were observed in Vt and BF between the two protocols in either the men or women at any level (confidence intervals up to 0.958 in all the groups). T_i/T_tot remained constant, and all increases in VE were strongly related to the respective increases in Vt/T_i. Plots of data for men and women showed a curvilinear relation between Vt and BF which could be fitted with an exponential function with a strong correlation (R² = 0.98 for men and 0.97 for women).

Conclusions: Graphic expression of Vt v BF is a useful nomogram for the routine assessment of ventilatory response during exercise in healthy trained subjects.

     

Arteriovenous malformations of the vein of Galen

Vein of Galen arteriovenous malformations encompass a diverse group of vascular anomalies that share a common feature: dilatation of the vein of Galen. Although clinical presentations are highly variable, depending on age of presentation, signs and symptoms overlap between age groups. The association of heart failure and cranial bruit constitutes the most striking clinical presentation in neonates. However, less severe and fulminant modes of presentation are frequent in older infants, children, and adults. Treatment approaches consist of symptomatic treatment of heart failure on the one hand and of surgery or endovascular treatment on the other. The results of the latter have improved in recent years, opening up a broad spectrum of new possibilities. We present the case of an asymptomatic 15-day-old neonate who presented an arteriovenous malformation of the vein of Galen and who was treated with endovascular occlusion of the arterial afferents. An excellent result was obtained with no evidence of neurological abnormalities.     

Recurrent polychondritis: apropos of a case

We present a case of relapsing polychondritis which presented as hypoacusis and showed several peculiarities. The initial diagnosis was serous otitis. After a more careful study we found certain details which made us suspect a relapsing polychondritis. The diagnosis was confirmed by a biopsy of the nasal cartilage and a detailed systemic study was performed. As distinctive characteristics we found a mixed hypoacusis, in which the sensorineural component was partially recovered following corticoid treatment.