Penile Zipper and Ring Injuries

Etiology

Typically, zipper injuries occur in young children who are dressing and zipping while paying attention to something else. It is certainly not unusual for young children to be easily distracted. Zipper injuries also happen in adults but less often. In adults, the condition typically occurs when the zipper is being closed by a relative or caretaker, as in patients with dementia or individuals with other neurocognitive disabilities who are unable to fully dress themselves. In children, only toilet seat injuries are more common causes of penile trauma than zippers. It is unclear if "going commando" (not using underwear) is a contributing factor. Known risk factors for penile zipper injuries include younger age (less than 18 years), not being circumcised, and requiring assistance for dressing.

Penile ring entrapments occur when a ring is placed around the penis, usually intended for erotic purposes, and cannot be removed by the patient. This causes increasing venous stasis leading to worsening edema, reduced lymphatic and arterial flow, bruising, cyanosis, ischemia, necrosis, and eventual gangrene. Patients are typically adults who often delay coming to the Emergency Department due to embarrassment. This often results in a more severe level of injury when they finally appear for medical assistance.[3]

Epidemiology

The majority of zipper injury cases are in children and younger teenagers. The overall incidence is quite low, comprising less than 0.5% of all emergency room pediatric visits. The most common cause is having the foreskin becomes caught between the two sides of the zipper during closure due to distraction or inattention. This also occurs in adults who are unable to dress themselves due to dementia, congenital disabilities, traumatic brain injury, cerebral palsy, spinal cord injuries, and similar conditions. Other people will need to close the zipper when dressing in these patients.[4] Since the overall incidence of zipper-related penile injuries in adults is so low, caregivers often do not recognize the risk. In patients who have no sensation in the genital area or are unable to communicate, this can become a potentially serious injury due to delayed recognition.

The exact incidence of penile ring entrapments is unknown, but it is considered quite rare, with less than 100 cases reported in the medical literature.[5] When it occurs, it is almost always in adults.[3] Reported ages are 15 to 56 years of age ranging from 3 hours to 1 month![6] In young children, hair can accidentally cause a similar tourniquet effect, called penile hair strangulation, that can mimic paraphimosis in appearance.[7] The most commonly reported age is three years, but it has been reported in young boys from neonates to 5 years.

Pathophysiology

Typically, the pathophysiology for both conditions is similar to direct tissue damage to the foreskin or penile skin from compression and entrapment. The injury may demonstrate bleeding, swelling, pain, contusions, bruising, and other signs of tissue damage. In general, the longer the tissue is trapped, the greater the degree of tissue damage, edema, bruising, scarring, and trauma. Therefore, the conditions should be relieved as quickly as reasonably possible.

Of the two problems, penile ring entrapment is potentially more dangerous as it can quickly progress to more serious and permanent injury to the penis. Zipper injuries are more likely to show tissue damage to the entrapped skin, while penile ring entrapment will tend to progress from venous stasis to distal edema with lymphatic and arterial blockage, followed by increasing ischemia. This ischemia can progress to infarction, necrosis, urethral fistulas, and either self-amputation or gangrene in a matter of hours.[8] It can even result in death.[9] Ring compression may be sufficient to interfere with voiding and cause urinary retention requiring suprapubic tube placement. Ring entrapments longer than 72 hours are likely to be the most serious. Non-metallic rings tend to cause more serious injuries as their limited degree of elasticity results in greater compression. 

Rings of various materials have been reported, including, but not limited to, metal rings, wedding rings, iron sleeves, nuts, washers, plastic bottles, bull rings, hammerheads, and rubber bands. Almost any material that can be manufactured into a ring can potentially be used. This complicates removal as, ultimately, this will depend on the nature of the ring material and the equipment available.

Penile hair strangulation typically occurs in young male children less than five years of age. It is often from long maternal hair, which accidentally becomes wrapped around the penis and then shortens as it dries out, causing penile strangulation.[7] It typically occurs in circumcised children, and the most common site of hair entrapment is at the coronal sulcus. If the problem is not diagnosed early and the constricting hair tourniquet removed, it can damage the dorsal neurovascular bundle with loss of sensation to the glans penis as well as develop urethrocutaneous fistulas, damage the corpora, transect the glans, create a urethral stricture, and even cause partial or total penile auto-amputation distal to the constriction.[10][11][12][13] In chronic cases, the hair can become embedded in the penile tissue and may not even be visible. Fortunately, these cases are rare but should be considered in any young child with distal penile edema, especially if circumcised.  

Two types of zipper engagement of the penile or preputial skin are seen. Most commonly, the foreskin is engaged by the median bar sliding mechanism of the zipper. Less commonly, the penile skin may become trapped by the interlocking teeth of the zipper, with the median slider body being pulled up beyond the engagement area.[14]

History and Physical

The patient will often present with significant pain. In adults, there will also be considerable embarrassment in even discussing the problem. Examiners should be aware of this and deal with the issue professionally. Most zipper cases will typically only involve partial involvement of the prepuce. However, in some cases, there may be a full-thickness involvement of the foreskin with considerable tissue damage.

Penile ring entrapment injuries are also fairly obvious on physical examination, although there may be so much tissue edema that the ring may not be immediately visible. It is also possible that the ring is not just around the penis, but it is also around the base of the scrotum, which makes removal more complicated.

In most cases, patients and caregivers will already have attempted manual extraction. Such attempts usually cause additional tissue damage. They also delay the patient's presentation to the Emergency Department. This typically results in additional pain, swelling, bruising, and tissue damage.

A grading system for penile ring entrapment injuries has been proposed by Dawood et al.  Grade 1 includes cases of distal edema with only superficial penile tissue damage. Grade 2 encompasses deep tissue damage involving the urethra and/or corpora. Finally, Grade 3 involves fistula formation, significant tissue loss, necrosis, or gangrene.[3]

Evaluation

The diagnosis is usually made quite easily based on a simple history and physical examination. No special laboratories or imaging is required. 

Treatment / Management

Zipper Injuries

It is preferable if the zipper can be removed or dismantled without formal surgical intervention. Extreme care should be used to minimize further tissue damage when attempting manual extraction or removal.[15](B2)

The following are the initial steps that can be taken to remove the zipper in the Emergency Department. Usually, little or no sedation or anesthesia is necessary but should be used as required. 

1. Edema around the site of the injury can be reduced by the use of continuous compression from a narrow elastic wrap. This will gently but continuously compress the injured area and slowly reduce the edema, allowing for easier manipulation and removal of the zipper. Roughly twenty minutes is usually enough to reduce the penile edema sufficiently to allow for further treatment.
2. The initial attempt at release should generally start by applying mineral oil to help soften the entrapped tissue. Five to ten minutes is usually enough to help facilitate the gentle removal of the skin from the zipper with simple manipulation by hand or with a cotton swab, but this can be extended to 30 minutes if necessary.[4][16] The disadvantage of this technique is that, if unsuccessful, it leaves the entrapped skin and zipper slippery with the lubricant, so it should be skipped if a more mechanical solution will obviously be necessary.[4]
3. The next step is to mechanically remove, destroy, or otherwise separate the zipper to free up the prepuce or other entrapped penile tissue. First, cut the cloth portion of the zipper with scissors or wire cutters as close as possible to the zipper teeth on either side. This will usually allow the individual teeth of the zipper to fall out and release the entrapped skin. This can easily be done without sedation or local anesthesia. Bleeding can suddenly arise once the skin is released due to a previously unsuspected injury to the underlying tissue, which was hidden by tissue compression from the entrapment.
4. Various hand tools can be used to cut the center, sliding portion of the zipper. Cutting the median bar will destroy the central locking portion of the zipper mechanism and help separate the two interlocking strips. This may require using significant hand tools such as a small hacksaw, scissors, bone cutter, or wire cutters.[17][18]
5. Another approach is to make a transverse incision in the material on the lateral margin of the zipper, where it pinches the foreskin.[19]
6. Needle-nosed pliers can be used to compress the central median slider bar laterally from both the right and left sides. This will result in a loosening of the engaged, interlocking teeth and allow the trapped skin to be released. The cloth of the zipper immediately lateral to the central sliding bar needs to be cut to allow the pliers full access to both sides. Cutting into the fabric of the pants is sometimes required.[20]
7. Alternatively, the flat end of a screwdriver can be used to pry the zipper open. This is done by forcibly separating the zipper's interlocking teeth. The flat end of the screwdriver is placed parallel to the zipper in an open area close to the entrapment. When the screwdriver is rotated 90 degrees, it will very forcibly pry the two ends of the zipper apart.[21] This method can exert substantial force and may cause pain. The released tissue may start bleeding or demonstrate other signs of injury, such as abrasions, contusions, or lacerations. It should now be possible to identify any potential injury to the underlying penile tissue, corpora, or urethra. Urology should be involved if any of these areas are injured beyond that of the prepuce.
8. Insert the thin flat edge of a small screwdriver in the slot between the inner and outer faceplates of the median slider bar, then start twisting. This will separate and widen the gap between the faceplates and disengage the trapped penile tissue.[21]
9. If entrapped skin removal by mechanical destruction of the zipper and gentle manipulative techniques, as noted above, are unsuccessful, further treatment usually requires the application of a topical local anesthetic. This is especially useful in the pediatric population. Adults and older children may require a formal penile block.
10. A formal penile block can be performed to provide immediate pain relief and allow for additional manipulation. A penile block is performed similarly to a digital or finger block. A circumferential, superficial injection is made with a local anesthetic (without epinephrine), starting at the base of the penis and continuing completely around the penile base. Alternatively, an injection can be given more deeply on either side of the neurovascular bundle under Buck's fascia. A penile block may also be performed using ultrasound guidance.[22]
11. Treatment now progresses to a more surgical intervention approach. Incision and/or removal of part, or even all, of the prepuce in the Emergency Department may be required. A urology consultation is generally recommended due to the potential significant injury to the penis or urethral tissue.  
12. A circumcision can be done as a last resort. This is usually reserved for those cases when a simple local excision or dorsal slit is not feasible, and all other treatment options have failed. If circumcision is recommended, it may need to be postponed to allow for the resolution of the initial traumatic edema.[19] Further, there may be cultural or religious objections to circumcision from the family.
(B2)

One procedure that should be avoided is to attempt painful manipulation in the Emergency Department without adequate anesthesia/analgesia. This is counterproductive and uncomfortable for the patient. Anesthesia is usually required to remove the prepuce skin from the zipper in children and young teenagers when simple manipulative techniques fail. Procedural sedation will typically be adequate due to the short duration of the procedure. Once sedated, surgical instruments, such as a bone cutter, may safely remove the zipper.

The prognosis is excellent for most children. Skin injuries to the prepuce should generally be closed primarily using absorbable sutures. If the skin cannot be extracted from the zipper, an excision of the affected area can be done. This then undergoes primary repair or can be left open. In such a case, the skin edges should be oversewn, again with absorbable sutures.

Penile Ring Entrapment

There are two basic ways of getting entrapped penile rings off of the penis: finding a way to eventually slide the ring off (sliding technique) or cutting the ring off. There is no single consensus approach to treatment as the degree of injury and type of ring materials are so variable. However, a stepwise approach, from simple to more advanced, is recommended.[5] Prolonged entrapment and strangulation of more than 30 minutes can lead to irreversible damage due to edema and ischemia.[23](B3)

The sliding technique is recommended as the initial approach as it is the easiest and fastest way to remove the constricting ring. Local or regional anesthesia is usually recommended. Lubrication with mineral oil, machine oil, and even olive oil have all been used successfully. This is usually complemented by distal penile compression, usually via a continuous elastic wrap. Using a lubricant allows for easier passage of the ring, but it also makes it more difficult to grasp and hold the constricting band well enough to attempt extraction. In these cases, vascular tape can be passed behind the ring using forceps or a hemostat. Four, six, or eight tapes are spread out around the ring and grasped with Kelly clamps. These can then be used to provide considerable traction even to well-lubricated and slippery rings.[8][24][25][26](B3)

Aspiration of the edema fluid by needle skin punctures has been done with some success. Superficial, longitudinal skin incisions along the lateral penile shaft, together with an elastic compression wrap, allow more of the edematous fluid to escape. A Winter's shunt (corpora cavernosa to corpora spongiosa), the same shunt used in cases of priapism, has also been used to help with distal corporal fluid decompression, further facilitating ring removal. Direct corporal aspiration has also been used with limited success. 

The modified Coban/string technique has been used successfully to remove penile rings and should be attempted prior to surgery when possible. This technique uses a narrow, one-inch thin elastic wrap such as Coban (3M Corp.) for distal penile compression and ring extraction.[27][28](B3)

• First, standard elastic compression and aspiration are done as described above to minimize distal penile edema as much as possible.
• The Coban is then used to wrap the penis circumferentially, starting distally and slowly moving proximally, creating overlapping layers. 
• The bands of the Coban should be tightly overlapping and advancing about one-third of the Coban's width per layer. 
• When the ring is reached, a forceps or curved hemostat is used to pull the proximal end of the Coban under the ring.
• Some time should be given for the Coban to provide additional compression and help reduce the distal penile edema as much as possible.
• Next, the lubricant is liberally applied over the wrapped penis to make it quite slippery.
• Finally, the proximal end of the Coban is grasped with a clamp and slowly pulled distally towards the glans penis, which will apply significant pressure on the ring to move towards the glans. 

This is similar to the "string" technique frequently used to extract rings from fingers. One of the differences is the greater degree of edema that can occur with the penis compared to the finger. The technique works well if the distal penile edema is not too severe after elastic compression. Coban is somewhat sticky, so it is not as likely to migrate during extraction as some other elastic wraps might. It is thin but also very strong and therefore is not expected to tear even when pulled quite hard. The tight, interlocking layers are designed to avoid any bumps, bulges, or restrictions to ring extraction.[27]

In some cases, an edematous ring of tissue may develop just proximal to the glans. If it appears that this circular edematous tissue is preventing ring extraction, it can be surgically incised or even excised, leaving sufficient skin for reapproximation after ring removal.[26] (B3)

These techniques have been helpful in some cases; they are all intended to help deal with the sometimes extreme penile edema preventing ring removal.[5]

Ring cutting will be necessary if the above sliding methods are not successful. Much will depend on the nature of the ring material. Non-metallic rings are more easily surgically cut than metallic bands. Cutting is best done in the operating room with the patient under general anesthesia to guarantee that there is no movement while using potentially dangerous cutting tools near the genitalia. The obvious tools to use first include scissors and a ring cutter, as these are readily available in most Emergency Departments. The skin directly under the ring should be protected, which can be done with a tongue depressor or a scalpel handle. Orthopedic pin cutters and a Gigli saw can then be safely used to cut the ring. A handheld rotating electric saw and industrial bolt cutters are additional tools that can be used when other methods fail. Such tools are available from hospital maintenance as they are not typically found in most operating rooms. Constant irrigation with cold water or saline is needed to minimize the heat these saws generate, which can result in tissue burns or pressure injuries.[5][29][30][31][23](B3)

If all the above fail, higher-strength electrical saws are available from most Fire Departments. Usually, two separate cuts are needed 180 degrees apart to allow the ring to easily separate. Again, great care must be taken to avoid direct injury to the underlying tissue and from the heat generated by the powerful saws.

Industrial bolt cutters have also been used, but they are awkward to use and not readily available.

A specially designed saw specifically for use in the Emergency Department for penile rings has been described but is not commercially available.[32] 

Differential Diagnosis

There is usually no doubt about the diagnosis, which is fairly evident on direct examination. Some of the lesions that could conceivably cause some confusion would include the following:

• Balanoposthitis (infectious/contact-induced)
• Contact dermatitis
• Insect bites
• Paraphimosis
• Penile amputation
• Penile contusion
• Penile fracture
• Penile hair strangulation
• Penile laceration
• Penile paraphimosis
• Penile trauma
• Postinstrumentation, for example, indwelling catheter insertion
• Sexual assault
• Traumatic epididymitis
• Urethritis

Prognosis

The prognosis is generally good, even with extensive soft tissue injury. Patients with urethral injuries may develop strictures. More severe injuries may require grafting and other repair techniques. 

Complications

Potential complications include stricture formation, penile partial or complete self-amputation, fistula formation, necrosis, gangrene, and death.