A paraphimosis is defined as the inability to reduce a proximally positioned foreskin over the glans penis and back to its normal anatomic position. The most common causes for a paraphimosis are iatrogenic. Following examination or instrumentation of the penis, medical personnel may forget to reduce the foreskin over the glans. This is particularly true of patients who are sedated, confused, demented, delirious, or in a nursing home. Patients may fail to reduce their foreskin after intercourse or urination. In infants and toddlers, the foreskin does not become fully mobile until after 3 years of age. This predisposes them to a paraphimosis when well-meaning caregivers forcibly retract the foreskin during cleaning. A paraphimosis may also occur when a narrowed (phimotic) foreskin is retracted and unable to be reduced.
A patient with a paraphimosis usually presents with severe pain in the distal penis. The process may have a more indolent presentation in persons with impaired pain sensation, such as the elderly or diabetics. As they are often unable to complain of pain, patients with altered mental status are at risk for complications of a paraphimosis. This includes penile ulceration, infection, gangrene, and partial penile autoamputation.1 A careful and complete physical examination is mandatory in these patients. Penile edema secondary to a paraphimosis must be differentiated from edema due to infection, trauma, or allergic reactions.
The foreskin is composed of a double layer of epidermis overlying subcutaneous tissue. It is attached to the skin at the base of the glans penis. The foreskin covers the glans to a variable degree and can usually be completely pulled over the glans. In a paraphimosis, the foreskin is retracted behind the glans and becomes edematous. The base of the foreskin is the location of the constricting or phimotic ring (Figures 148-1 & 148-2).
The anatomy of a paraphimosis.
A paraphimosis. A. Superior view. B. Inferior view.
Arterial supply to the foreskin is derived from superficial branches of the external pudendal artery, which originates from the femoral artery. These superficial arteries do not communicate with the deep arteries of the penis. Arterial supply to the glans penis is derived from the paired dorsal arteries of the penis, which originate from the penile artery. These dorsal penile arteries run deep to Buck's fascia to enter the glans at the coronal sulcus. Arterial supply to the glans penis is thus entirely separate from that of the foreskin.
A retracted foreskin will block lymphatic drainage from the distal penis. As arterial inflow continues, lack of lymphatic drainage will cause a progressive edema of the penis distal to the retracted foreskin. As the foreskin continues to swell the phimotic ring becomes ...