Recessive dystrophic forms of EB are burdened with a high psychological impact for patients and family members. A multidisciplinary approach to manage the disease is crucial. In addition, “mitten hands” compromise the functional development of the hands in children with EB. So, an early surgical approach is of paramount importance. In our experience, but also in literature, pseudosindatiles in patients with this disease are characterized by high rates of recurrence 6-7 . The scar tissue of the hands can alter the anatomical structures, including the vascular-nerve pedicels. Conventional surgical techniques for “mitten hand” are limited to the release of pseudosyndactylies and wound coverage. During surgical procedures, care should be taken not to damage the vascular peduncles, in order to avoid necrotic skin phenomena with additional iatrogenic damage. Split-thickness skin grafts provide coverage of wide areas, however, availability of healthy skin for autologous grafts of dermis and difficulty healing at the donor site can be major problems in EB patients. The use of skin substitutes in patients with bullous epidermolysis has been described in the literature; often in combination with skin grafts 9-10. The surgical approach is limited to a temporary resolution 7-10. Of paramount importance are the function preservation and the increase of free recurrence time. Through a careful analysis of our technique, it was possible to improve our results thanks to the use of microsurgical technique and the use of INTEGRA® dermal regeneration template.
In fact, we believe that magnifying loupes have allowed us to preserve the vascular-nervous peduncles in these patients, especially if in paediatric age. The higher skills and expertise of the Surgeons using the microscopic lenses in the release of pseudosyndactylies also helped to gain better results avoiding surgical damages.
We believe that through our protocol using a bilayer dermal regeneration template it is possible to avoid skin grafting and therefore iatrogenic damage and further surgery.
Artificial dermis, as Integra®, is an acellular purely bilaminate synthetic construct consisting of an outer silicone (polysiloxane) semipermeable membrane and an inner porous matrix of collagen-glycosaminoglycan.
The outer layer serves as an epidermal substitute and provides mechanical protection, a flexible adherent covering for the wound surface, and heat and moisture modulation of the wound, prevent formation of granulation tissue on the matrix surface and adds increased tear strength to the device. Whereas the inner layer, composed of bovine tendon type I collagen cross-linked to chondroitin-6-sulfate, is a biologic-based acellular dermal scaffold and promotes cellular ingrowth (it’s histoconductive/ histoinductive and allow for fibroblast proliferation and migration into the dermal scaffold and capillary growth). In particular glycosaminoglycan provides elasticity to the matrix, controls the biodegradation rate, and maintains a more open pore structure that allows cell migration into the matrix.
The porous layer of the matrix is strictly applied to the wound bed at the first stage. It acts as a template for the ingrowth of host fibroblasts and endothelial cells and is gradually replaced by host (endogenous) collagen, forming a new dermal layer (neodermis). At approximately 3 weeks, when well-vascularized neodermis is usually formed, the silicone layer may be peeled off and replaced with cultured epithelial cells or autologous thin split-thickness skin graft (applied directly to the surface of the vascularized neodermis).
The major disadvantage of the artificial dermis use is the need for a second operative procedure to provide epidermal coverage; moreover, in our protocol for EB hands we use the Integra®- glove as an advanced wound dressing avoiding the second phase of skin graft and obtaining an almost complete and spontaneous re-epithelialization.
On the other hand the use of artificial dermis offers many advantages, such as: immediate availability, possibility to cover large defects, no donor-site morbidity, good scarring, and early recovery.
In addition, the anti-inflammatory properties and physical characteristics of INTEGRA ® allowed us to perform pain-free dressing and achieve more stable coverage over time. The coverage of noble structures, such as vascular and nerve peduncles, has been found to perform well. We believe that coverage through our technique has allowed a lower rate of early recurrence. In fact, inter-digital spaces have had a slight tendency toward fusion during the healing phase, probably thanks to the INTEGRA® layer. The severity of the primary disease, the degree of hand deformity and the age of the patient at their initial submission are also considerable factors, which will be studied in subsequent studies.
Finally, these surgical procedures are light and can be carried on in local anaesthesia and sedation; in particular, we performed: regional anaesthesia (brachial plexus), or deep sedation with fentanyl and propofol plus local anaesthetic infiltration, or deep sedation with ketamine and fentanyl plus local anaesthetic infiltration.11 We avoid to perform general anaesthesia because of high risk of iatrogenic damage of intubation in this kind of patients. With our new protocol the medications are painless, so we don’t use anaesthesia.