Compromised Skin Graft And Flap

Theodore A. Mesimeris

General Hospital St.Paul, Hyperbaric Department, E.Antistasis 161, P.C. 55134,

Thessaloniki, Greece

Abstract: Hyperbaric oxygen has been effectively used as adjunct therapy in wound healing treatment of acute or chronic surgical conditions. Covering or reconstructing complex wounds is accomplished by skin grafts or flaps. Transferred tissues may be compromised due to different etiologies requiring proper therapy. Hypoxia due to inadequate grafted tissue oxygenation, involves hyperbaric oxygen use as adjunct therapy. Experimental and clinical studies concerning hyperbaric oxygen have shown results favoring the attachment of threatened grafted tissues. Capillary proliferation, protection from reperfusion injury, anti-edema action, rheological capillary improvement and protection from infection are among the demonstrated effects of hyperbaric hyperoxia. Definition of the etiology and proper timing of hyperbaric oxygen therapy through a collaboration of the plastic surgeon with the hyperbaric physician are considered necessary for the desired final outcome

Keywords: compromised skin graft; compromised flap; hyperbaric oxygen; reperfusion injury; plastic surgery

1. INTRODUCTION

Plastic surgery has a predominant role in the management of complex wounds and is indispensable for covering areas where important loss of tissue has taken place.

Wound healing is a delicate balance process related to many factors that may interfere with the reparative tissular response both to acute traumatic ischemia or chronic hypoxic wounds.

There are numerous surgical choices in order to close any kind of wound which may be divided in multiple categories depending on surgical complexicity and patient factors.

Proper wound management is related both to the perfusion correction and oxygen tissular delivery and to the local environment of the lesion, as are the regular debridement, the anti-bacteriological control through local or systematic antibiotic therapy and the suitable dressings to the wound nature. The wound healing is completed by either primary or secondary intention through granulation, epithelization and contraction.

Complex wound reconstruction is accomplished by transferring tissues like skin grafts or flaps from a different part of the body to the wound area.

The survival of these transplanted living tissues depends on many factors of which the most important is an adequate blood supply.

In normal conditions hyperbaric oxygen is not required for the survival of non-compromised flaps and grafts and may be useful only when viability of the transplanted tissue is doubtful or uncertain.

When the local microcirculation is inadequate to support the transplanted tissue, oxygen tissular improvement is of critical importance.

Today it is clear that hyperbaric oxygen (HBO) may provide a distinctive enhancement of the wound healing process by optimizing the tissular oxygen level in cases where a decreased microcirculation or hypoxia is present.

Furthermore the experimental and clinical experience of HBO therapy provide strong evidence not only in the collagen maturation and the angiogenetic stimulus but also in many important phenomena related to the wound microenvironment during the wound healing period as are the reduction of the ischaemia - reperfusion injury, the enhancement of growth promoting factors, the improvement of hemo-rheological status and the resistance to infection.

In order to analyze the principles of Hyperbaric Medicine and identify the common physiological aspects with Plastic Surgery in the wound healing process, a review of basic terms is necessary.

2. SKIN GRAFTS

A skin graft is a segment of skin detached completely from its bed and transferred to another site. Composed by epidermis and dermis, skin grafts are quite different from flaps as they are avascular where as the flaps have an innate vascular support.

The transplanted tissue placed on the host basis survives primarily as oxygen diffuses into it from the underlying wound bed and later relies on the promoted angiogenesis of the basis and the wound margins.

According to the thickness of dermis, skin grafts can be either full thickness or split thickness. The split thickness grafts are often used to cover granulated wound areas as they require less ideal conditions and they may survive a diminished vascularity1. Full thickness grafts are preferred in wounds with well-developed vasculature, non-contaminated and of small size.

Composite grafts contain more than one kind of tissue (skin, fascia, muscle, bone).

According to the donor origin, grafts are defined as autografts, (skin transferred from the same body) allografts, (skin transplanted from a different body) xenografts, (animal grafts) or biologic skin grafts (combination of living cells in collagen matrix).

Whether the plastic surgeon will choose to apply a skin graft depends on the vasculature status of the wound bed and the survival of the graft depends on rapidly acquiring an effective blood supply1.

Thus the possible adjunctive enhancement of HBO application in skin grafts should be related to the promotion of adequate granulation tissue development in the wound area.

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