COMBINED THERAPIES - SKIN TRANSPLANT AND PLASTIC SURGERY TECHNIQUES FOR CHILDREN WITH EXTENSIVE BURNS OVER 30% OF TOTAL BODY SURFACE AREA
Bums represent a severe health problem. The combination of skin transplant with plastic surgery techniques constitutes the modern approach in extensive bums therapy. Intrinsic and extrinsic factors (regeneration capacity, following possibilities, therapeutic compliance) influence the therapeutic procedure. The plan of surgical approaches of the burns has to be suited to the person. Certain regions have better indications for a certain procedure. Temporary skin covering (natural skin substitutes - allografts, xenografts, amniotic membranes; synthetic and semi synthetic skin substitutes - synthetic structures and collagen-based materials) and definitive (auto grafts, flaps) constitute surgical options for the acute phase treatment. The preservation of natural skin substitutes constitutes an important issue. Surgical treatment of post burns sequels (excisions, flaps, tissue expansion, auto grafts) improves the severe disabilities of these patients. In our clinic, although the number and severity of the cases are relatively constant in the last 10 years, we managed to decrease significantly the general mortality of the children extensive burns, to improve esthetic and functional aspects, leading to an easier social reinsertion and harmonious development of the child. The suggested theme represents a stage of the research project ,Scientific and technological research center in the area of tissue transplant and skin grafts", that our clinic currently develops with the center VIASAN. This project has a great importance for the standardization and improving average and serious burns treatments of the adults and children, finally aiming toward significantly reducing mortality and treatment costs for these patients. The burns represent a serious problem of public health because of the great number of cases, severity of lesions, reserved prognosis, great number and severity of complications, long duration of treatment, frequently functional, aesthetic, psychological and social disastrous effects and because of the high costs they imply. For pediatric age pathology, the burns represent one of the most frequent etiologies. In our clinic between 1300-1400 of new cases are admitted yearly, among which 600-700 burns. From the total burns admitted about 30% are major burns that are over 30% total body surface area (TBSA). These cases necessitate after initial hemodynamic and electrolytic re-equilibration, local treatment of lesions, a correct therapeutic approach having a decisive role for the favorable evolution. Major objectives are the limitation of losses through the burn lesion and quick spontaneously epithelization for partial superficial burns, and the prompt excision of the necrotic tissues and immediately skin covering for the partial deep and deep burns. Thus a problem of great importance becomes finding appropriate methods of skin covering, the ultimate goal being definitively covering with the least sacrifice for the unaffected tissues, obtaining good functional and aesthetical results. A large series of options are available; we mention and detail those ones frequently used in our clinic. In the extensive deep burns, in which the skin reserves of the patient are insufficient to achieve an efficient skin covering, we temporarily use skin subsitutes, to allow the organism to regenerate its own reserves. Natural skin substitutes:
Synthetic and semi-synthetic skin substitutes: Bilayered synthetic structures Composite materials based on collagen (BIOBRANE) The qualities of an ideal skin substitute:
Natural skin subsitutes Allografts - tissue transfer from one individual to another of the same species. Allografts were first transplanted organs and gained knowledge in this field constituted the fundamentals of modern transplant immunology. Because of the marked skin antigenity, only autografts are not rejected (and in rare cases isografts). Immunosupresion from the major burns can delay allografts reject up to several weeks. At this rate allografts are utilized with good result, with or without autografts, in the extensive burns. "Sandwich" technique overlaps a layer of medium expanded allograft over intermediary largely expanded autografts proved to have superior results to autografts use only. The donor potential evaluation Absolute contraindication:
Relative contraindication:
Allograft advantages:
Allografts disadvantages
LARGE APPLICABILLITY:
The use of allografts in our clinic led us to the next conclusions: Allografts cannot be replaced presently with any synthetic, semisynthetic or culture material. Allow the improvement of vital prognosis and life quality in major burns. Their use reduces the average duration of hospitalization, the number and the seriousness of the complications and the therapeutic costs in the major burns. Allografts are accessible, easy to harvest and preserve on relative long periods. They do not generate subsequent costs as the in the case of organ transplants (immunosupression, reject, reinterventions). They represent a strategic resource for situation of collective accidents, disasters, natural calamities. XENOGRAFTS - transfer from one species to another. Pig xenografts have been used either as temporary dressing or as "sandwich" - like structures, covering largely expanded autografts in the extensiveburns. The unique adherence qualities of pig xenografts, scientifically explained through the biologic process of binding fibrin-elastin, are responsible for the antibacterial effect, too. The use of xenografts is also beneficial because it stimulates formation of granulation tissues and prepares the wound for future autografting. The utilization of xenografts was extended, not merely for covering large burns before grafting, but also for temporary covering of exposed vessels and tendons, leg ulcers, donor zones. Xenografts advantages
Xenografts disadvantages
In the year 2003 in our clinic xenografts were used for a large number of cases of extensive burns. Following this experience, we reached the next conclusions: freshly harvested xenografts are more efficient than those ones criopreserved xenografts adhere to the receptor bed freshly excised and with a reduced degree of contamination, constituting a biologic dressing of good quality for 7-10 days the process of rejection occurs after 10-14 days, but we prefer the surgical excision followed by autografting xenografts near autografts do not influence negatively the evolution of neighboring autografts the subjacent formed dermic matrix has a good quality, favorable for autografting we prefer the expansion of the xenograft, thus preventing subjacent exudates accumulation and infection. Amniotic membranes are used as the allografts. They contain fibronectin, collagen and is foreseen with a fine epithelial layer which functions like the barrier of the epidermis. Adherence to the wound is reduced. Advantages:
Disadvantages:
Harvesting - from living donors or corpses, with strict respect to the measures of asepsis and in concordance with the legislation. Criopreservation (CPA) The preservation is achieved initially through criopreservation. This implies crioprotection in glycerol 15ø/0, initial thermal stabilization through controlled freezing, gradually decreasing temperature with 0,3 C degrees/min, and then grafts stockage in liquid nitrogen at -160 -196 C degrees. The penetration with ultraviolet radiation and use of glycerol 15% increases the duration of preservation, eliminate the viral agents, but he reduces the viability of the conserved tissues. Criopreservation did not diminish the risk for infectious complications compared to allografts from fresh corpses and did not eliminate the problem of antigenicity. In addition to all this, the method is complicated expensive. Preservation in glycerol 85% (GPA) It is currently the method of preservation of the natural skin substitutes most frequently used in our clinic, all over the world the opinion inclining toward the substitution of criopreservation with preservation in glycerol 85%. In our vision presents the following advantages against criopreservation:
The main advantage of GPA (glycerol preserved allografts) is the ability to cover and adhere to the wound bed. The use of GPA as skin substitute is now accepted for:
The use of GPA as the dermal substitute GPA are characterized by their property of allowing capillaries growth from the wound bed through the layer of collagen of the matrix. By now the intimate mechanism of this process of angiogenesis is not elucidated. After a period of 12-14 days in which the former lesions are covered with GPA, numerous capillaries are observed which leads to a better integration of the allografts. DEFINITIVE SHIN COVERING The graft represents the ideal solution of definitive skin covering (easy harvesting, the exceptional covering quality, reduced costs). Autografts: can be full thickness (containing epidermis and derma in totality, including annexes) or intermediary (epidermis and a variable thickness from derma). Full thickness grafts, the first type described, assure an excellent cosmetic outfit but has a more difficult integration. The available skin surface is limited by the necessity to close the donor zone through suture. In the situation in which it is necessary the covering of larger surfaces with full thickness skin grafts, as in the case covering burns of the face, the donor zone can be increased with preoperative expansion techniques. Intermediary skin graft is now the most utilized form of tissue transplant in modern plastic surgery. It has the advantage of being harvested from wide areas and of having a good integration but it is predisposed to contraction and hypertrophic scars, especially in children Their donor zone heals through spontaneous insular epitethelization starting from the epithelial rests from the annexes. The expansion 1:1,5 up to 1: 9 is utilized especially in extensive burns, assuring an improved drainage of the graft beds but the cosmetic appearance after epithelization is deficitary. Not expanded grafts can be used in extensive burns up to 55% and are used in burs larger than 55% only for the face and hands (due to superior cosmetic result). The limits of the method regard extensive burns, in which potential donor skin reserves are insufficient, new methods of temporary or definitive (dermo-epidermic cultures of keratinocites in the presence of fibroblasts) skin covering being needed. Flaps The use of flaps as surgical technique for definitive skin covering in the acute phase of the child burns has limited indications, reserved to special situations (flaps being used mainly in the reconstruction postcombustional phase). These indications are: inadequate bed for grafting, localization not suited to grafting (articulations), the need of support tissue, the need of vascularised structures transfer. When traditional method of covering are not indicated (such as the cases that require the covering tendons, nerves, sanguine vessels, bones and articulations with necrotic or infected zones, caused by electric current, burns through contact or flame, the utilization of flaps on random circulation, of axial flaps and of free transferred flaps can be salutary. The use of flaps is useful in functional zones with deep burns causing the relative quick closing of the affected zones and allowing early recovery of the functionality for the affected segments (like at the level of radiocarpian, elbow, heel, hand articulations). Muscular flaps are better solutions than skin flaps or fasciocutaneous flap in the case of a contamined recipient bed. The decision to use a free flap has to be thorough because it takes much time, the difficulty is high, and the risk of flap non surviving is considerable. RECONSTRUCTIVE SURGERY OF THE PATIENTS WHO SUFFERED EXTENSIVE BURNS The proper treatment of acute phase reduces the necessity for reconstructive surgery after burns. However, even in optimal situations reconstructive interventions are necessary, usually in the first years after the accident, especially in children where the scar pathology is aggravated by growth. The aim of the interventions is obtaining functional and cosmetic reinsertion as good and as fast as possible. The surgical program for the child who suffered extensive burns must be strictly individualized, to allow early return in the family, not to affect the school learning periods, to assure functional autonomy, to be understood and accepted by the family and to be accompanied by sustained means to consolidate the results (pressure therapy, positioning, hydrotherapy, kinetotherapy and psychotherapy). Reconstructive surgical interventions are realized combining a series of basic techniques: incision of scar relaxation and grafting, scar excision and grafting, Z plashes, random flaps or axial flaps. Scar tissue relaxation /excision Scar tissue relaxation is realized through transversal incision of the scar cords followed by grafting. The complete excision of the scar tissue (recommended especially for scar hypertrophic placards) is realized if the donor zone permits the covering of the defect. The use of flaps Although scar relaxation through incisions and excisions followed by grafting are major techniques in post burn reconstruction, most frequently used in our clinic, we use reconstruction methods with local flaps (of translation, of rotation, of transposition) whenever possible. Planned and executed properly z plasty is a very efficient reconstruction method. Many times we had to modify Z plasty according to local vascularization and tissue elasticity. Regional or distant flaps have limited indications for the child. In our practice we used numerous regional cross-type flaps for deep burns of the fingers caused by contact or electrocution and for complex lesions with exposure of noble elements of the legs. The free transfers are use exceptionally for children, in our opinion having indications in situations that can generate serious invalidities (amputations). Tissue expansion Complex methods for closing defects sometimes in our practice resulted in scaring and changes of the donor zone more non esthetic and mutilated than the initial lesion. Thus, we consider tissue expansion as one of the best methods of covering defects resulted after scar excision. In our clinic we accomplish 1820 interventions of this kind per year. Different shape and sizes expanders are used, but we prefer high capacity expanders of 400500 ml, which give comfort for covering. The intervention classically has more operative times. We reached the conclusion that for children one operative time intervention is preferred because of the discomfort caused by the bearing of the expander, a foreign body, which usually overtakes patient's understanding ability. The careful surgical planning is essential for the success. The size and form of the expander, the used incision, the localization, as much as the technique must be anticipated from the start. More expanders can be used in the same time. The medium duration for filling is 3 weeks - 1 month, depending on the size of the defect, the degree of tissue elasticity, obtaining an increase ratio of 1,5/1. We had the best results for tissue expansion in the case of postcombustional alopecia, cervical contractures and anterior thorax scars. The combination of methods of skin transplant with plastic surgery techniques represents a fundamental principle in the modern approach of one of the most serious and mutilating affections - the extensive burn. The surgical plan has to be suited to the person. Certain anatomic zones require certain interventions rather than others. The surgical method has to include the problems of topography and functionality in order to improve the aspect and functionality. We confronted delicate cases in which the optimal choice proved difficult and apparently not the most logical, nor the simplest, because we had to consider many intrinsic and extrinsic factors, like that the child has different regenerative capacity or organization aspects (social status, following possibilities and especially child's and family's compliance to the treatment). In our clinic, although the number and severity of the cases were constant in the last 10 years, through the use of the mentioned therapies, we managed to decrease the general mortality of the child with extensive burns significantly, to improve the esthetic and functional aspects, thus helping the social reintegration and harmonious development of the child.
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