Blast overpressure has become an increasing cause of brain injuries in both military and civilian populations. Though blast's direct effects on the cochlea and vestibular organs are active areas of study, little attention has been given to the ear's contribution to the overall spectrum of blast injury. Acute autonomic responses to blast exposure, including bradycardia and hypotension, can cause hypoxia and contribute to blast-induced neurotrauma. Existing literature suggests that these autonomic responses are elicited through blast impacting the thorax and lungs. We hypothesize that the unprotected ear also provides a vulnerable locus for blast to cause autonomic responses. We designed a blast generator that delivers controlled overpressure waves into the ear canal without impacting surrounding tissues in order to study the ear's specific contribution to blast injury. Anesthetized adult rats' left ears were exposed to a single blast wave ranging from 0 to 110 PSI (0–758 kPa). Blast exposed rats exhibited decreased heart rates and blood pressures with increased blast intensity, similar to results gathered using shock tubes and whole-body exposure in the literature. While rats exposed to blasts below 50 PSI (345 kPa) exhibited increased respiratory rate with increased blast intensity, some rats exposed to blasts higher than 50 PSI (345 kPa) stopped breathing immediately and ultimately died. These autonomic responses were significantly reduced in vagally denervated rats, again similar to whole-body exposure literature. These results support the hypothesis that the unprotected ear contributes to the autonomic responses to blast.
Purpose: Three cases of dislocation of a Gore-Tex scleral-sutured EnVista intraocular lens are reported. The tensile strength of the lens eyelets under two suturing methods is assessed. Pursuant surgical considerations are discussed.Methods: A chart review was performed to identify cases of scleral-sutured EnVista lens dislocations. In addition, six EnVista lenses were suspended in a balanced salt solution tank, tied either with suture over haptic or simple pass technique. Eyelet tensile strength was calculated by gradual addition of weights. Eyelet fracture position and width were measured. The tensile strength of one additional EnVista lens was assessed in open air.Patients: In a retrospective, consecutive case series, three dislocated lenses were identified out of 17 surgeries from one institution. Two dislocations occurred postoperatively, and one occurred intraoperatively.Results: The EnVista eyelet demonstrated greater tensile strength tied with the simple pass method (0.27 ± 0.017 N, n = 3) than with the suture over haptic method (0.15 ± 0.016 N, n = 3; P = 0.0015). Eyelet fracture location corresponded to tensile strength. The lens in air withstood greater tensile stress.Conclusion: Stress is placed on different regions of the eyelet with each suturing method. Simple pass may withstand greater tension and decrease risk for lens fracture, but the operating surgeon must consider multiple factors when forming an operative plan.
A 7-year-old girl with no relevant past medical history presented with a several-month history of an expanding, darkening lesion on the left arm. She reported occasional tenderness but no itching, drainage, or bleeding. Examination revealed a 1.5-by 1.2-cm, hyperpigmented, firm, protuberant, nonscaly plaque on the proximal side of the left arm (Figure 1).Excisional biopsy with 1-mm margins was performed and submitted for histologic evaluation (Figures 2 and 3).
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