Keywords pediatric - penis - skin grafts - lymphedema
Introduction
Penile congenital abnormalities or traumas require adequate skin coverage for reconstruction.[1 ] Local flaps are preferred by surgeons, but they are not always available.[1 ] Alternatively, full-thickness skin grafts (FTSGs), split-thickness skin grafts (STSGs),
and artificial dermis implants may be considered. The strategy is chosen depending
on the location and size of the defect. Several reports were published on adult diseases
requiring penile skin grafts.[2 ] However, only a few reports exist on penile skin grafts in the pediatric population,
as diseases that cause severe penile tissue loss appear to be rare in children. Pediatric
surgeons encounter hypospadias-related complications and penile skin deficiency but
often prefer to reconstruct the urethra with a tabularized (or on lay-staged) buccal
mucosal graft and cover the free graft with available penile skin.[3 ] Hence, pediatric penile skin grafting is rarely performed. We present a case series
of four patients who underwent penile skin grafting at our department from 2012 to
2019.
Case Report
Cases 1 and 2
A 4.11-year-old boy and an 8-year-old boy suffered a high fall-related penile injury.
The 4.11-year-old boy was treated 8 hours after injury. The defect area measured 3.0 × 2.5 cm.
He received a FTSG after debridement because the time after injury was relatively
short and the penile wound surface was relatively clean ([Fig. 1B ]). Full-thickness skin was harvested from the lateral inguinal region. The inguinal
donor wound was sutured. The dressing and the catheter were removed 10 days after
the operation.
Fig. 1 A 4.11-year-old boy suffered a high fall-related penile injury and presented with
tearing of the penile skin, loss of the penile shaft skin, and retention of the front
of the foreskin (A ). The boy received a full-thickness skin graft (FTSG) (B ). The FTSG survived almost completely at 10 days after surgery, and the small area
of skin necrosis healed after changing of the dressing (C ). The scar was slightly hyperplastic and hyperpigmented 8 months after surgery (D ).
The 8-year-old boy was admitted to the hospital 24 hours after injury. The defect
penile skin area measured 2.0 × 2.8 cm, and the defect scrotal skin area measured
3.0 × 3.5 cm. He received debridement and an artificial dermis implant (PELNAC, GUNZE
Corporation, Japan) during the primary surgery, followed by a thick STSG 14 days after
surgery ([Fig. 2B ]).
Fig. 2 An 8-year-old boy suffered a high fall-related penile injury and presented with loss
of the penile shaft skin and part of the scrotal skin, and retention of the front
of the foreskin (A ). The split-thickness skin graft survived completely as observed 7 days after surgery
(B ). The scar was noted to be flat and hypopigmented 3 years after surgery (C ).
Case 3
A 6.6-year-old boy, who sustained an electric cautery circumcision-related penile
injury, was transferred from the urology department to the burns and plastic surgery
department 10 days after injury. The defect area measured 1.5 × 2.5 cm. After debridement,
a thick STSG was performed ([Fig. 3B ]).
Fig. 3 A 6.6-year-old boy suffered an electric cautery ritual circumcision-related penile
injury and presented with loss of the penile skin and the glans penis (A ). After debridement (B ), the split-thickness skin graft survived completely as observed 1 month after surgery
(C ).
Case 4
A 12.5-year-old boy, who suffered a traffic accident-related penile injury, received
primary suturing at another hospital. The penile skin necrosis area measured 2.2 × 3.1 cm,
and the left thigh necrosis skin area measured 38 × 15 cm. He was transferred to our
department 10 days after injury, and he received debridement and an artificial dermis
implant (acellular dermal matrix) during the primary surgery. After 14 days, the acellular
dermal matrix was removed, and a 0.2-mm STSG was placed on the granulation tissue
wound ([Fig. 4B ]).
Fig. 4 A 12.5-year-old boy suffered a traffic accident-related penile injury and presented
with tearing of most of the penile skin and part of the left thigh skin, and presented
with retention of the inner side of the foreskin (A ). The split-thickness skin graft survived completely; however, lymphedema of the
distal penile skin had developed 1 year after surgery (B ). After foreskin plastic surgery, the scar was observed to be flat and hypopigmented
(C ).
This STSG was harvested from the scalp using a Zimmer electric dermatome. The donor
site was covered with antibiotic dressing and healed naturally after 2 weeks. The
penile dressing and the catheter were removed 7 days after STSG placement.
A Foley catheter was inserted and retained throughout the treatment. We used the dressing
for hypospadias surgery as a reference to design the skin graft dressing. On the inner
side, a mesh-like lipid hydrogel dressing (UrgoTul, Laboratories URGO, France) was
evenly applied to the grafted skin so as to form a moderately tight sheath and to
avoid dressing adhesion. An antibiotic ointment (mupirocin) was applied to the second
layer, and the outer layer was wrapped with an elastic dressing. The graft was applied
tightly to the wound surface, and the absence of dissolution or scabbing was considered
to indicate good skin graft survival. The Vancouver scar scale (VSS; Baryza and Baryza,
1995) was used to evaluate the scar quality in all patients. The scale consists of
the following variables: vascularity, pliability, height, and pigmentation ([Supplementary Table 1 ]).
The three thick STSGs survived completely, with no signs of dissolution or scabbing
([Figs. 2 ], [3 ], and [4C ]). The FTSG survived almost completely, with a small area of skin necrosis healing
remaining after the dressing was changed ([Fig. 1D ]). The 12.5-year-old boy gradually developed lymphedema of the distal foreskin ([Fig. 4B ]), and he received prepuce plastic surgery 6 months after skin grafting ([Fig. 4C ]). He reported that he could achieve an erection and experienced no pain during urination.
All patients were able to urinate easily. The VSS scores of these four patients are
presented in [Supplementary Table 1 ]. Scar vascularity and pliability in all four patients were close to those of normal
skin. The scars after STSG were hypopigmented and flat, whereas the scar after the
FTSG was hyperpigmented, showing slight hyperplasia (< 2 mm). All parents were satisfied
with the appearance and function of the penis.
Discussion
Some adult diseases lead to severe penis tissue loss and require skin grafting, for
example, infection, trauma, burns, malignancy, skin disorders, and primary lymphedema.[4 ] However, these conditions are rare in children. Nevertheless, we treated four children
over the past 8 years whose penile skin defects were caused by trauma. In a pediatric
hypospadias review, only 23 patients underwent FTSG, and 4 patients received STSG,
among 215 patients; the 4 patients experienced a complete graft take, but secondary
contraction and ulceration were observed and associated with sexual activity.[5 ] Thus, patients with hypospadias or “hypospadias cripples” requiring skin grafts
are also relatively rare.
An ongoing debate exists about the optimal skin type to be used for penile skin grafts.
A greater amount of dermis is included in FTSG than in STSG; therefore, some important
distinctions in the nature and potential uses of the two types of grafts should be
borne in mind.[6 ] For FTSG exhibiting a greater metabolic demand and requiring a well-vascularized
recipient site, their survival is more uncertain. In contrast, STSGs demonstrate a
lower metabolic demand and require less ideal conditions for survival; therefore,
STSGs exhibit a much broader application range than FTSGs.[7 ]
[8 ]
[9 ]
[10 ] FTSGs display a higher degree of primary contraction, which is the recoil occurring
immediately after the skin graft is harvested and is related to the amount of dermis
elastin in the tissue. FTSGs may lose up to 40% of their surface area, whereas STSGs
typically lose only up to 10%.[11 ] Over time, FTSGs exhibit a tendency to resist secondary contraction, which refers
to the contraction of a skin graft after healing. Once secondary contraction ends,
FTSGs tend to stretch and grow with the individual, whereas STSGs do not tend to expand,[11 ] which may cause contraction or scarring.
As the penile skin is thin, hairless, and flexible, and it undergoes a substantial
change in size with penile erection, some researchers suggested FTSG as the preferred
choice for penile skin graft.[12 ]
[13 ] Chertin et al[14 ] reported penile STSG in 17 children and adolescents, with 94% graft take, with 6
sexually active patients reporting normal sexual intercourse and sensation; none of
the patients experienced shrinkage of the STSG. Alwaal et al[13 ] reported a successful outcome for genital STSG in 52 out of 54 adult patients, with
maintained or improved erection, normal voiding, good cosmetic outcome, and normal
mobility. Black et al[9 ] reported penile STSG in nine adult patients, and all experienced a complete graft
take. A satisfactory cosmetic outcome was obtained at a mean follow-up of 6 months,
and erectile function and ejaculation were preserved in potent patients. In our four
patients, the three STSGs showed complete graft survival, and the FTSG showed almost
complete survival, with a small area of skin necrosis healing after changing of the
dressing. The small area of skin necrosis may have been caused by a contaminated wound
or/and be due to the change in penile size with erection, which caused poor metabolism
and blood supply in the FTSG. All boys were able to urinate easily, and the 12.5-year-old
boy could achieve an erection without experiencing any pain. Based on the above-listed
observations and the results from our own study, thick STSG appears to be the most
appropriate choice for penile skin reconstruction.
Long-term complications of penile skin grafting should be borne in mind. The 12.5-year-old
boy who received an artificial dermis implant (acellular dermal matrix) and a thick
STSG gradually developed lymphedema of the distal penile skin ([Fig. 4B ]) and required extra foreskin plastic surgery. Diaz et al noted[15 ] that lymphedema may develop if any excess distal penile skin is not excised, and
limiting the amount of mucosal collar or consider direct anastomosis to the glans
is prudent. When loss of the proximal penile skin occurs, the tendency is to preserve
any viable distal skin. However, when loss of the proximal penile skin occurs, the
proximal dartos layer is usually lost, resulting in disruption of lymphatic drainage
of the distal penile skin. The native skin should be resected up to the level of the
glans to avoid a ring of lymphedematous skin developing around the glans. If skin
loss is not circumferential, leaving the native skin in place is preferable, especially
if several days of observation have not resulted in any increase in skin edema.[6 ] The 12.5-year-old boy received an artificial dermis implant (acellular dermal matrix)
during primary surgery, and the 8-year-old boy received an artificial dermis implant
(PELNAC, GUNZE Corporation, Japan) during primary surgery. However, only the 12.5-year-old
boy developed lymphedema. The PELNAC grows on the wound bed and forms granulation
tissue, with a structure similar to that of the dermis. However, the acellular dermal
matrix is a short-term onlay, which covers the wound bed and stimulates the growth
of granulation tissue. The matrix was eventually removed. Whether the implant was
the cause of the lymphedema remains unknown, and so, more cases and studies are required.
Conclusion
In conclusion, pediatric penile skin grafting is a rare procedure. Based on our experience
and observations published in the scientific literature, thick STSG appears to be
the most appropriate choice for pediatric penile skin reconstruction. Lymphedema of
the foreskin is an important long-term complication of penile skin grafting.
