Blunt subclavian artery trauma is an uncommon but challenging surgical problem. The purpose of this study was to retrospectively review the management of blunt subclavian artery injuries treated by the Trauma and Vascular Surgery Services at the East Tennessee State University-affiliated hospitals between 1992 and 1998. Six patients with seven blunt subclavian artery injuries were identified. Physical signs indicating blunt subclavian artery injury were pain or contusion around the shoulder joint; fractures of the clavicle, scapula, or ribs; periclavicular hematomas; and ipsilateral pulse or neurologic deficits. Seven subclavian artery injuries were treated-two arterial transections, two pseudoaneurysms, and three intimal dissections. Associated injuries included four clavicle fractures, one humerus fracture, one combined rib and scapular fractures, and two pneumothoraxes. Vascular surgical treatment included three primary arterial repairs, two saphenous vein interposition grafts, and one polytetrafluoroethylene (PTFE) graft. One patient was treated nonoperatively with anticoagulation. No deaths occurred. Morbidity occurred in two patients with chronic upper extremity neuropathy producing prolonged disability from pain and weakness; one patient had reflex sympathetic dystrophy, and the other had a brachial plexus injury. In conclusion, blunt subclavian artery trauma can be successfully managed with early use of arteriography and prompt surgical correction by a variety of vascular techniques. Vascular morbidity is usually low, but long-term disability because of chronic neuropathy may result from associated brachial plexus nerve injury despite a successful arterial repair.

Self-folding represents an attractive way to convert two-dimensional (2D) material sheets into three-dimensional (3D) objects in a hands-free manner. This paper describes a simple approach to self-fold pre-strained polystyrene (PS) sheets using microwaves.

Self-folding converts two-dimensional (2D) sheets into three-dimensional (3D) objects in a hands-free manner. This paper demonstrates a simple approach to self-fold commercially available, millimeter-thick thermoplastic polymer sheets. The process begins by first stretching poly(methyl methacrylate) (PMMA), polystyrene (PS), or polycarbonate (PC) sheets using an extensometer at elevated temperatures close to the glass transition temperature (Tg) of each sheet. Localizing the strain to a small strip creates a “hinge,” which folds in response to asymmetric heating of the sheet. Although there are a number of ways to supply heat, here a heat gun delivers heat to one side of the hinge to create the necessary temperature gradient through the polymer sheet. When the local temperature exceeds the Tg of the polymer, the strain in the hinged region relaxes. Because strain relaxation occurs gradually across the sheet thickness, the polymer sheet folds in the direction toward the heating source. A simple geometric model predicts the dihedral angle of the sheet based on the thickness of the sheet and width of the hinge. This paper reports for the first time that this approach to folding works for a variety of thermoplastics using sheets that are significantly thicker (∼10 times) than those reported previously.