Injury to the skin and soft tissues of the penis and scrotum commonly results from entrapment inside a zipper mechanism. Most of these injuries occur in school-age boys during opening or closing of the zipper, when tissue may be caught in the tracks or become entangled within the fastener mechanism (1). The goal of therapy is to provide a relatively painless and rapid extrication of the involved area without inflicting further injury. The techniques are straightforward and may be performed by physicians at any level of training. If local or regional anesthesia is not required, nonphysician health care providers also may perform the procedures outlined in this chapter.

The school-age boy who is dressing himself without using protective undergarments is at highest risk for zipper injuries. For this reason, parents should be wary of pajamas that contain such mechanisms. Although any loose tissue can become caught inside a zipper, the majority of zipper injuries involve uncircumcised penile foreskin. The redundant tissue located on the ventral aspect of the circumcised penis also is at risk for this type of injury. Once the tissue is caught inside the zipper, swelling may occur and may complicate the extrication procedure.

A zipper is composed of two opposing rows of teeth that interlock inside a sliding zipper fastener mechanism. The sliding portion consists of two face plates that are bridged by a “diamond” or median bar. As the fastener mechanism draws the two rows of teeth together on either side of the median bar, it aligns them such that the teeth interlock. Unless this alignment is maintained in a two-dimensional plane, the teeth edges fall apart. This relationship is the basis for the following techniques, which work equally well for both metal and plastic zippers.

Whenever tissue is entangled inside a zipper fastener or between the teeth of a zipper, the clinician should attempt to extricate the tissue. Using excessive force is not warranted and may cause further damage to the tissue. No absolute contraindications exist to these techniques, but if the extraction proves difficult, urologic referral is most appropriate. A urologist should be consulted for cases that involve the urethra or fail to respond to the following procedures. Any blood at the meatus or hematuria should alert the clinician to the possibility of an underlying urethral injury.

The clinician can approach the extraction of tissue from a zipper mechanism using one of the following techniques: (a) mineral oil extraction, (b) cutting the zipper cloth, or (c) cutting the median bar.

Procedural sedation and analgesia (Chapter 33) should be considered before starting the procedure. Ice should be applied through a moist cloth to minimize swelling while setting
up the sedation and anesthesia. Most children will require local or regional anesthesia after a superficial disinfectant is applied. A direct injection to the affected site may increase edema and complicate the extraction, so regional anesthesia techniques, such as dorsal penile block (Chapter 35) or circumferential penile block, should be considered.