INTRODUCTION
Plexiform neurofibroma is a benign peripheral nerve sheath tumor surrounding multiple
nervous fascicles. It usually is present at birth and often becomes physically apparent
within the first 2-5 years of life, generating morbidity and cosmetic problems. Despite
being considered an uncommon skin tumor, the plexiform neurofibroma is the most often
congenital tumor associated with NF1 and has a 2%-5% chance of transformation to malignant
peripheral nerve sheath tumors in this setting1-3.
Forearm and hand damage impairs its functional and social role. Successful management
of complex wounds is necessary for the overall rehabilitation of these patients4,5. The goals of forearm coverage reconstruction are to protect the structures running
to the wrist and hand and prevent scarring that leads to movement loss. Therefore,
it promotes patients’ functional mobility of the whole limb and lets them return to
work and resume their life6.
The lack of muscular layers on the arm’s anterior surface makes coverage of tendons
challenging and may require pedicle or free flaps for treatment. Each technique’s
advantages and disadvantages in the management of complex wounds must be taken into
account before deciding the treatment option. These variables include bulkiness, donor
site morbidity, patient discomfort for a long time and unfavorable cosmetic and functional
results5,6.
The introduction of advanced wound care technologies, including negative pressure
wound therapy (NPWT) and bioengineered tissues such as acellular dermal matrices (ADMs),
has reduced the need for complex surgical procedures with the right indication7-10.
The Pelnac™ (Gunze Co., Ltd., Kyoto, Japan) is an ADM with a bilayer dermal substitute,
which consists of the underlying atelocollagen matrix layer acting as a scaffold for
dermal regeneration the overlying semipermeable silicone layer acting as a temporary
epidermis11.
The application of Pelnac™ for the treatment of forearm injuries involving tendons
has not been extensively studied, though the ongoing literature suggests it is a powerful
tool for treating such cases11.
OBJECTIVE
We present our experience using ADM for coverage of a large forearm defect. We discuss
its advantages and possible drawbacks.
CASE REPORT
The patient signed an informed consent form, and the research followed the Helsinki
principles.
A 31-year-old woman presented to the plastic surgery division with a giant plexiform
neurofibroma on the right forearm (Figure 1). She had a past medical history for tetralogy of Fallot, corrected surgically, and
neurofibromatosis. The forearm tendons were exposed after careful resection (Figure 2), the forearm tendons were exposed (Figure 3). The defect was then covered with graftable Pelnac™ with 3mm thickness and 12 X
24cm2, fixed with 4-0 monocryl sutures. Small punctures were made into the overlying
silicon layer to facilitate effusion drainage (Figure 4). Dressings were made with Jelonet™ and occlusive bandages. Changing was made every
48 hours. After 10 days, the ADM silicone layer was removed, and a fenestrated autologous
thin split-thickness skin graft (STSG) was harvested from the thigh region and then
placed on the ADM sutured with 4-0 monocryl. The same previously described dressings
were made and kept for 7 days.
Figure 1 - Giant plexiform neurofibroma on the right forearm.
Figure 1 - Giant plexiform neurofibroma on the right forearm.
Figure 2 - Forearm tendons exposed after resection.
Figure 2 - Forearm tendons exposed after resection.
Figure 3 - Plexiform neurofibroma after resection.
Figure 3 - Plexiform neurofibroma after resection.
Figure 4 - Defect covered with graftable Pelnac™ with 3 mm thickness and width 12 X 24cm2, fixed with 4-0 monocryl sutures. Small stabs were made into the overlying silicon
layer to facilitate effusion drainage.
Figure 4 - Defect covered with graftable Pelnac™ with 3 mm thickness and width 12 X 24cm2, fixed with 4-0 monocryl sutures. Small stabs were made into the overlying silicon
layer to facilitate effusion drainage.
On day 7, the ADM showed good signs of engraftment (Figure 5). On day 17, we observed a 95% graft take; some debris was removed without any signs
of hematoma, seroma, or infection. Intense physical therapy and abundant local hydration
were started and performed for 3 months.
Figure 5 - Acellular dermal matrix on day 7 with good signs of engraftment.
Figure 5 - Acellular dermal matrix on day 7 with good signs of engraftment.
At the 3-month follow-up, the reconstruction was stable without contouring defects.
The Vancouver Scar Scale score was 3, the hand had a full range of motion, and the
patient had no problems in her daily activities (Figure 6).
Figure 6 - The 3-month follow-up, reconstruction stable without contouring defects, the hand
had full range of motion, and the patient had no problems in daily activities.
Figure 6 - The 3-month follow-up, reconstruction stable without contouring defects, the hand
had full range of motion, and the patient had no problems in daily activities.
DISCUSSION
Giant plexiform neurinoma is a benign disease, but it may compromise large areas.
Before its excision, reconstruction concerns and options should be considered to avoid
transoperative pitfalls.
Most peripheral neurofibromas are solitary lesions. The presence of large, plexiform
or multiple neurofibromas is rare, with a limited number of reported cases of lesions
with such dimensions and localization. The management of patients with plexiform neurofibroma
is not well defined; it is traditionally focused on relieving the symptoms1. Surgical excision of the lesions is the only therapy available to this date. However,
the results can be poor, and the procedures can be complicated due to several variables
such as size, localization, vascular and neural involvement, the microscopic extension
of the tumor and the high rate of tumor re-growth3,12.
Traditionally, flap reconstruction has been the primary treatment option for extensive
tendon exposure on the forearm. Nevertheless, it has a variable success rate in some
studies regarding flap viability and donor site morbidity. Furthermore, flaps may
be limited by the magnitude of the defect and restricted donor sites, especially in
patients with significant comorbidities.
ADM has become a popular alternative method in recent years and was reported to provide
favorable outcomes in various causes11,13-15. ADM combined with STGS has resulted in encouraging outcomes in treating wounds in
terms of scar quality, aesthetic appearance, functional recovery and donor site morbidity16. Pelnac™ is a type of ADM that allows dermis-like tissue growth into a matrix layer
and vascularization over areas of exposed tendons, providing a powerful alternative
for the reconstruction of these defects.
Compared to the traditional autologous skin flap transplantation, Pelnac™ combined
with autologous split-thickness skin grafting more likely resulted in a favorable
clinical outcome in treating hand complex wounds in terms of scar quality (VSS), aesthetic
appearance, functional recovery and donor site morbidity17. Comparing ADMs in mice, despite some differences in the granulation tissue thickness,
inflammatory response, and blood vessel density, is similar in wounds treated with
Pelnac and other ADMs. This data suggests that dermal substitutes have a similarly
favorable biological behavior and could be successfully implanted18.
A clean wound is mandatory for a successful procedure. Any devitalized tissue would
potentially cause infection and failure of the wound repair. Small stabs into the
overlying silicon layer to facilitate drainage of effusion, as performed in this case,
are described in the ongoing literature to diminish the infection risk. In cases with
suspected contaminated wounds, NPWT can be utilized to allow ADM to integrate11.
On every dressing change, the transparent silicone layer allows adequate monitoring
of vascularization status and development of potential complications such as infection,
hematoma, or seroma.
The main disadvantage of ADMs, such as the Pelnac™, is the high cost, risk of infection,
and the need for at least two procedures in most of the ADMs available (although it
could be done at once with second-generation matrices)16. Techniques should always be compared scientifically to help aid medical decision19.
CONCLUSION
ADM appears to be a useful option in covering complex defects in the forearm, allowing
for less morbidity and rapid functional recovery.
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1. Hospital de Clínicas de Porto Alegre, Department of Plastic Surgery, Porto Alegre,
RS, Brazil.
2. Universidade de Passo Fundo, Faculdade de Medicina, Passo Fundo, RS, Brazil.
Corresponding author: Eduardo Madalosso Zanin, Rua Ramiro Barcelos, 2350, Porto Alegre, RS, Brazil, Zip Code 90035-007, E-mail:
eduardo.zanin@gmail.com
Article received: August 23, 2020.
Article accepted: April 23, 2021.
Conflitos de interesse: não há.
