Zipper injuries may involve any area of exposed skin.1-21 Zipper injuries usually occur to the foreskin, the skin of the penis, and the scrotum. Zipper injuries result in skin and soft tissue entrapment when the zipper is opened or closed. It primarily occurs in uncircumcised young boys, intoxicated adults, the mentally handicapped, males not wearing underwear, and elderly men suffering from movement or cognitive disorders. The most common type of zipper entrapment compresses the skin between the sliding piece (fastener mechanism) and the teeth of the zipper. Another type of entrapment involves the skin between the teeth of the zipper after the sliding piece has moved beyond the area.1,2 Multiple methods to extract the entrapped skin have been reported.1-21 These methods range from manipulation to tooth-by-tooth extraction to circumcision. Significant swelling can obscure the zipper mechanism and make standard approaches impossible necessitating ingenuity to avoid secondary injury.16 Treatment should be guided by the type of entrapment.1 Removal of the zipper can be performed quickly using basic tools to extract the entrapped tissue and thus prevent or limit secondary injury.
ANATOMY AND PATHOPHYSIOLOGY
The zipper is a simple device that is used daily by millions of people (Figure 183-1). Although universally present on clothing and equipment, the simple zipper mechanism may be difficult to conceptualize. It consists of a sliding piece that moves in two directions. The sliding piece is composed of a front and back plate connected by the median bar (Figures 183-1B and 183-1C).5 Each plate has a small raised edge that helps to guide the two rows of teeth together (Figures 183-1B and 183-1C). These edges do not connect to each other as the only portion of contact between the two plates is via the median bar. Without this bar the mechanism falls apart. The median bar is usually located at the top of the sliding piece. A finger grip is attached to the front plate of the sliding piece and functions as a handle to move the sliding piece. The teeth are two opposing sets of rectangular metal or plastic pieces attached to fabric to keep them aligned (Figures 183-1A and 183-1D). Moving the sliding piece across an open zipper will interlock the teeth and close the zipper. Reversing the sliding piece direction will unlock the teeth and open the zipper. The importance of this interdigitating order is evident when this back-and-forth order is violated and the sliding piece cannot pass the defect without great force, if at all.