Farm Accident Causes Penoscrotal Degloving

MAY 24, 2007
James F. Tycast MD
Resident in Urology
Saint Louis University Hospital
St. Louis, MO

Anand V. Palagiri MD
Pediatric Urology Fellow
Cardinal Glennon Children?s Hospital
St. Louis, MO

James M. Cummings MD
Professor of Surgery
Division of Urology
Saint Louis University Hospital
St. Louis, MO

Genital avulsion injuries are frightening for the patient and formidable to the surgeon.A rational approach to the situation helps produce a good outcome. Careful selection of which tissue to debride, along with proper selection of grafts and flaps for reconstruction, allows satisfactory results to be obtained and minimizes further morbidity. The authors report the case of a patient involved in a farming accident that resulted in penoscrotal degloving and discuss the principles that should be applied when repairing this type of injury.


Avulsion of the skin from the external genitalia is a rare surgical emergency. These injuries usually result from machinery accidents involving loose clothing that is rapidly and forcefully torn from the victim.1Genital avulsion injuries are terrifying for patients and challenging for first responders and physicians because of the skin loss involved. Fortunately, there is usually a negligible amount of blood loss, minimal pain at the time of injury, and little damage to the erectile tissue or the spermatic cord.

Case report
A 28-year-old man was working on a farm and suffered injury when he stepped over a power take-off (PTO) shaft from which the safety guard had been removed. He caught his coat in the PTO shaft and was pulled into the machinery, resulting in the degloving of his genital and perineal regions. At the scene of the accident, the patient was awake, alert, and oriented to person, place, and time. He was transported by helicopter to Saint Louis University Hospital. Physical examination revealed complete degloving of an area that measured 9 x 20 cm and encompassed the penile shaft, scrotum, and perineal region to the anal sphincter. The transporters had established hemostasis of the region with gauze, and the patient?s red blood cell count was within normal limits upon arrival to the hospital. His urethra appeared undamaged on retrograde urethrography, and an 18-French Foley catheter was placed for urinary diversion (Figure 1).

The patient was taken to the operating room, where a diverting colostomy was performed by the trauma surgery team to give the perineal region time to heal. Further evaluation by flexible sigmoidoscopy found no rectal injury. The penile and scrotal regions were irrigated and debrided of devitalized tissue, and the testes were placed in thigh pockets (Figure 2).

Postoperatively, the patient underwent daily whirlpool treatments to the genital area. He returned to the operating room 5 days later, where he received a 0.016-inch, unmeshed, split-thickness skin graft along the penile shaft. The graft was retrieved from his right thigh, attached to the corona and the base, and closed ventrally in a zigzag fashion (Figure 3). The testicles were sutured together in the midline, and a bipedicle flap was performed to cover his testicles and close the scrotal defect all the way up to the base of the penile shaft. The donor sites along the medial thigh were covered with a 0.012-inch, split-thickness, meshed skin graft.

Five months after his initial repair, the patient developed a scar contracture along the base of his penis and was having tethering of his erections. The scar contracture was released with good results, and the colostomy was reversed at that time.

Discussion
The PTO shaft was introduced during the 1930s and revolutionized North American agriculture by facilitating the efficient transfer of mechanical power between farm tractors and implements.2 The PTO shaft is one of the most persistent hazards associated with farm machinery, despite new industry standards requiring guard shields for these devices. Many farmers tamper with or remove these guards, claiming that they are an inconvenience. This permits injuries to occur, especially to the tractor or machinery operators, who are the victims of 78% of PTO shaft entanglements.2 In 70% of these cases, the guard shield was absent or damaged. In 63% of cases, a bare shaft, spring-loaded pushpin, or through bolt was the type of driveline component at the point of contact, and in 50% of cases, stationary equipment such as augers, elevators, posthole diggers, and grain mixers were involved.2

When penile skin avulsion injuries occur, repair should be undertaken as early as possible, because delays result in prolonged disability and contribute to bacterial colonization.3Although several penile coverage techniques have been used in the past, such as burial of the denuded shaft within the scrotum or use of a local flap, these injuries are best treated with a split-thickness skin graft. This graft provides good elasticity, flexibility, and looseness, and allows patients to have full, functional erections.

Before grafting the avulsed penis, it is necessary to catheterize the urethra. The penis is elongated to its full extent on the catheter, allowing for the appropriate graft length.4 Once the catheter is in place, all irregular edges of skin are trimmed away. Distal skin, even if it is in good condition, must be debrided to the coronal level, because prolonged distal edema commonly results secondary to disruption of the lymphatics that drain this tissue. Stretching residual skin to cover the penile shaft is not advised. Once the recipient bed has been prepared, a split-thickness skin graft should be harvested from a relatively hairless area, such as the thigh or abdominal wall. The graft must then be applied as a single sheet of medium thickness in an interdigitating, zigzag fashion to minimize longitudinal scar contracture, which can result from a straight closure along the full length of the penile shaft. The skin is placed directly on the fascia to prevent scarring beneath the graft. After the skin has healed, initially it is tight around the penile shaft and constricts erections in length and circumference, but it attains almost normal elasticity once the scar tissue beneath the skin graft softens. If further grafts or loosening are needed, additional skin can be added later. Some patients have been documented as experiencing pain with erections in the early postoperative period but, in our experience, these painful episodes rarely continue.

Scrotal skin avulsion can be more difficult to repair. The integument of the scrotum has many glands, scattered hairs, and ridges. It is also extremely loose, and the deeper layers contain the dartos, which is a thin layer of smooth muscle fibers. Beneath the dartos lie the intercolumnar fascia and the cremasteric fascia and muscle, which are important for thermoregulation of the testicles to maintain adequate spermatogenesis.5 It is therefore important that the testicles be replaced as close to their original location as possible. Criteria for reconstructing an encasement for the testicles include (1) providing adequate cover to the spermatic cords and testicles without undue tension or constriction; (2) proper protection of the scrotal contents against trauma; and (3) ensuring the patient?s comfort in any position or activity. Accordingly, when a sufficient quantity of scrotal skin remains after the trauma, it should be used to reconstruct the scrotum without delay. If very little scrotal skin is available, the surgeon may remedy this by using thigh pockets, thigh flaps, or a meshed split-thickness skin graft.

Immediate repair is often accomplished by creating thigh pockets; these can be temporary or permanent. Thigh pockets are created by embedding the testicles and spermatic cords in the most adjacent regions of the upper thighs.6The optimum position for these pockets is the medial upper thigh region, as far posterior as the length of the spermatic cords permit. It has been shown that if the testicles are placed in an anterior position, the spermatic cords may be placed under undue tension when the thighs are spread apart, depending on the length of the vasculature. Furthermore, patients report feeling more comfortable when the testicles are embedded at staggered levels in the medial thighs, because the testicles will not oppose each other when the thighs are brought together.

The scrotum is usually reconstructed with either flaps or a meshed split-thickness skin graft. Proponents of flap reconstruction cite a functional outcome, a sensate and hair-bearing scrotum, and more reliable coverage without the problems of graft take. Rotational thigh flaps are most appropriate when reconstruction was delayed for men with testes in thigh pockets. These flaps require redundant skin and yield the best results when there is only a thin layer of subcutaneous fat.6 The gentle envelopment of the testicles and spermatic cords in relatively thin thigh flaps suspended below and posterior to the phallus still promises good functional and cosmetic cover and position. The base of these thigh flaps should be set superiorly and slanted well medially. The shape should be paddle-like, with the spermatic cords running under the handle and the testicles resting like balls in the center of the paddles. When brought together, the pedicles must be long enough to reach each other below and behind the phallus without restrictive webbing. The size of the flaps must be generous enough to avoid undue pressure on the testicles.4

Surgeons who favor meshed graft repair state that this method gives a final appearance of rugation, is readily available, and allows free drainage of fluid between meshes.6The repair usually begins by burying the testicles in the thigh pockets, which allows pseudocapsules to develop around them during the first stage of repair. The fibrous areas that overlie the testicles are then used as a bed for the split-thickness grafts during the second and final stages of repair. An alternative staged procedure begins with burying the testicles in thigh pockets during the first stage, expansion of perineal skin to provide a two-compartment scrotum during the second stage, and ultimately performing bilateral orchidopexy.

Which procedure to use must be decided on a case-by-case basis but should include split-thickness skin grafting in situations that do not allow enough tissue for immediate reapproximation.

Conclusion
Genital avulsion injuries are rare surgical emergencies, which pose difficulties for the surgeon and can be devastating for the patient. Surgeons who are confronted with these injuries must take a rational approach to provide the patient with safe and timely care and produce a favorable outcome. As with most contaminated injuries, thorough debridement and infection control are essential for maintaining healthy tissue for reconstruction. The actual reconstruction procedure should be determined on an individual basis, but the combined use of thigh flaps and split-thickness skin grafts will provide a cosmetic and functional repair, in most cases.

References
1. Morey AF, Metro MJ, Carney KJ, et al. Consensus on genitourinary trauma: external genitalia. BJU Int. 2004;94(4):507-515.

2. Murphy DJ. Power take-off (PTO) safety. Centers for Disease Control and Prevention: National Agricultural Safety Database. Available at: www.cdc.gov/nasd/docs/d000701-d000800/d000745/d000745.html Accessed February 5, 2007.

3. McAninch JW. Management of genital skin loss. Urol Clin North Am. 1989;16(2): 387-397.

4. Millard DR Jr. Scrotal construction and reconstruction. Plast Reconstr Surg.1966;38(1):10-15.

5. Culp DA, Huffman WC. Temperature determination in the thigh with regard to burying the traumatically exposed testis. J Urol.1956;76(4):436-438.



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