Combination of artificial dermis and autologous skin grafting with negative pressure suction for refractory wounds
To understand the feasibility of combining artificial dermis and autologous skin with negative pressure suction in the treatment of difficult-to-heal wounds and to evaluate its therapeutic effect. Methods Thirty-one inpatients with 45 difficult-to-heal wounds were selected, including 25 cases of electric shock injury, 4 cases of avulsion injury and 2 cases of thermal extrusion injury. The area of trauma defect ranged from 1-4%, including 6 cases with nerve and tendon exposure and 4 cases with bone exposure. The surgical method was to expand and transplant artificial dermis plus negative pressure suction in phase I. The trauma was vascularized after one week, and in phase II, to transplant autologous thickened skin plus negative pressure suction. Results: 38 of 45 wounds healed well, 4 healed after dressing exchange, and 3 wounds were covered with flaps instead. Conclusion The combination of artificial dermis and autologous skin grafting with negative pressure suction for repairing difficult wounds provides a new option for difficult wounds because of the simplicity of the method, short operation time, high quality of wound healing, short duration of the disease, and minimal damage to the donor area.
Artificial dermis; autologous skin; negative pressure suction; difficult to heal wounds
Difficult to heal wounds are mostly seen in electrical burns, trauma, thermal crush injuries, chemical burns, and radiation injuries, where the wounds are deep to muscles, tendons, vascular nerves, and even bone tissues, with severe local tissue defects and necrosis, and the wounds are not easily covered and do not heal over time [1]. Various types of flap repair have positive efficacy, but the local surgical trauma is large, the operation time is long, the surgery is relatively difficult, and the donor area trauma still needs to be repaired. Difficult-to-heal wounds with severe local damage and poor substrate are generally difficult to repair with one-stage free flap implants. We explored the use of dermal scaffold and autologous skin combined with negative pressure suction treatment, and achieved more satisfactory results.
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Data and Methods
Clinical data and grouping
Thirty-one patients with difficult-to-heal wounds who were hospitalized in our hospital from September 2011 to September 2012 were selected. There were 23 male cases and 8 female cases with an average age of 38 years. There were 25 cases of electric shock injury, 4 cases of avulsion injury, and 2 cases of thermal extrusion injury. The traumas were located in 19 places on the hand, 6 on the wrist, 6 on the lower leg, and 14 on the foot. The area of traumatic defects ranged from 1-4%, including 6 cases of combined nerve and tendon exposure and 4 cases of bone exposure.
Artificial dermis
The artificial dermis we used, named Pinecore, is a kind of implantable artificial dermis, which has a two-layer structure, the upper layer is a silicone membrane layer, mainly for protection and fixation, and the lower layer is a collagen sponge layer, about 3 mm thick, from which the therapeutic effect comes. The collagen comes from the tendon of pigs, and through modification, the end of collagen (Atelocollagen) is removed, and then transformed through a series of processes, which is not easy to produce rejection after implantation in human body.
Closed Trauma Negative Pressure Drainage Dressing Kit (Vacuum Sealing Drainage Dressing Kit)
Ltd. is used in this group of cases. It consists of drainage tube, adhesive septum, medical sponge or absorbent dressing, oil gauze, barrier membrane, suction connection tube, trapezoidal connector, Y-connector, clip, water-blocking filter, negative pressure tank and flushing tube.
Surgical method
All patients were given promptly after admission to the hospital for wound crust debridement + biological dressing coverage, and the wound was debridged again after about one week of dressing change, covered with a suitable size of piña colada, fixed, external negative pressure suction device, and continuous negative pressure suction after surgery. The negative pressure suction device was removed after one week, and after sufficient cleaning and disinfection, the autologous bladed thick skin was grafted on the collagen layer sponge layer of the skinnex, and the negative pressure suction device was placed again, and the negative pressure suction device was removed after one week, and the autologous skin adhered to the trauma surface with good color transfer.
Results
Overall situation
In 45 wounds, the grafted epidermis adhered to the skin Nike and survived well. At 1-year follow-up, all traumatic skin adhesions were tight, flat, smooth, elastic and soft, with skin elasticity similar to normal skin, and good mobility and wear resistance.
Clinical evaluation of postoperative scarring of traumatic surfaces [2] (Vancouver Scar Scale VSS, which is a more common international method for scar assessment)
Color (M) Thickness (H) Vascular distribution (V) Softness (P)
Scar color vs. body Normal Scar skin tone vs. body Normal
Skin color of normal area Normal area approximate
Approximate
Lighter color <1mm Pinkish skin tone Softness (skin can be deformed with minimal resistance)
Mixed shade 1 to 2mm Reddish skin tone Soft (skin can be denatured under pressure)
Darker color 2 to 4mm Purple-red skin tone Hard (can’t denature, moves in
lumpy, resistance to pressure)
4mm curved (tissue is rope-like, scar recedes on extension)
Contracture (permanent shortening of the scar leading to disfigurement and distortion)
According to the VSS score, 22 cases scored 4, 5 cases scored 5, 2 cases scored 6, and 2 cases scored 7 to 8. Higher scores indicate more severe scarring.
Typical cases
Male, 48 years old, was admitted to the hospital 3 days after 10KV electric shock injury to the left upper and right lower extremities. On examination, a circular scorch wound was seen on the left wrist, swelling of the left hand was obvious, blood flow to the fingers was poor, and a cavernous scorch wound was seen on the palmar side of the left hand with necrotic muscle exostosis and exposed tendons. In the right calf, a large leather-like scab wound with a central soft tissue defect of 5 cm in diameter was seen, and the deep muscles were exposed. The burn area was 5%. After admission, the left wrist was incised and decompressed, and debridement surgery was performed on the third day. The left upper limb was severely disfigured and the left mid forearm was amputated, the right lower limb was scabbed and expanded + biological dressing (pig skin) covered, part of the necrotic tibialis anterior muscle was excised, the tibia was partially exposed, the lower 1/2 of the periosteum was necrotic and the bone was unhealthy; one week later, the right lower limb was debridement + skinned graft + VSD suction, part of the trauma of the trauma edge was pig skin, and the trauma was controlled with the skinned graft; one week later, the right lower limb was debridement + autologous skin extraction One week later, right lower limb debridement + autologous skin retrieval + VSD suction was performed. The VSD was replaced 3-5 days after surgery, and the medication was changed. The autologous skin of the pigskin-covered trauma healed worse than the autologous skin of the piñeck-covered trauma, and the skin piece expanded slowly and was less resistant to infection. The lower 1/2 of the exposed tibia was not healed, and then the necrotic bone cortex was surgically removed and the wound was healed by reapplying artificial dermis and autologous skin graft combined with negative pressure suction technique. (Figure
Figure 1 After wound debridement Figure 2 After skin grafting and pig skin covering
Figure 3 One week after autologous skin grafting Figure 4 Two weeks after autologous skin grafting
Female, 5 years old, was admitted to the hospital more than one month after trauma to the right lower extremity. The wound had been cleared several times in the external hospital. On examination: traumatic trauma was seen on the right calf, ankle and foot, with dry necrosis of the right foot’s first toe terminal segment, absence of the 2nd-4th toes, exposure of the 1st-3rd metatarsals and tarsus, and exposure of the flexor tendon with dry necrosis. Necrosis of the dorsalis pedis artery was cleared. Tendonous tissue wrapped around the exposed heel bone. The anterolateral aspect of the right ankle, the dorsum of the foot, the distal plantar aspect of the foot, and the heel were covered with a little necrotic tissue, and the trauma was infiltrated with inflammation. The trauma was cleared several times successively, and the inter-ecological tissue was preserved as much as possible. According to the trauma granulation formation, artificial dermis and autologous skin graft combined with negative pressure suction technique was applied to nibble and eliminate the trauma. After excision of necrotic bone tissue, the trauma healed with a change of medication, light scar, little pigmentation, and still able to walk on the ground. (Figures 5-8)
Figure 5 Post-evisceration Figure 6 1 week after Pinnacle graft
Figure 7 Dead bone resection Figure 8 1 year after wound healing
Male, 47 years old, was admitted to the hospital for 4 days with a 10KV voltage injury to the left upper limb, left foot and back. On examination, the left sole and toes were scab-like trauma, and the left [toe end phalanges were exposed. The trauma surface started to melt and smelled bad. The left foot was dilated, and the left foot was repaired with artificial dermis and autologous skin grafting combined with negative pressure suction technique. (Figures 9-12)
Figure 9 Plantar trauma Figure 10 Dorsal trauma of the toe
Figure 11 1 week after traumatic skin Nike grafting Figure 12 1 week after traumatic skin grafting
3. Discussion
The treatment of various types of clinically encountered difficult-to-heal wounds has always been a difficult subject. The wounds are often deep, with partial nerve, tendon, vascular and bone damage and exposure. The commonly used wound coverings are: skin flap, myocutaneous flap, fasciocutaneous flap, and free autologous skin graft to cover the wound, but the selection of graft is still a difficult point for wound repair.
Skin flaps and myocutaneous flaps have a large amount of repair tissue and strong resistance to infection, and are mostly used for treatment of joint, tendon, nerve or bone exposed wounds, but the flap coverage area often cannot completely cover the defect when the wound is too large. In cases where the total burn area is greater than 20%, the patient is unstable during shock, the patient is too old or too young, organ insufficiency, with inhalation injury, combined carbon monoxide poisoning, craniocerebral injury, uncontrolled sepsis or local invasive infection in burn wounds, and the patient is confused or uncooperative, flap repair of wounds should be prohibited or used with caution [2], and there are limitations to the treatment of difficult to heal wounds. In addition, the donor area of the skin flap and myocutaneous flap often needs to be repaired with skin implants, causing varying degrees of cosmetic defects and even varying degrees of functional impairment to the donor area, and the traumatic flap survives with a bloated deformity, which may require reoperative thinning of the flap at a later stage.
In this group of cases, the use of artificial dermis + negative pressure suction in the first phase to cover the trauma, and the use of autologous flap free grafting + negative pressure suction in the second phase have achieved good treatment results. The artificial dermis can effectively provide a dermal scaffold and increase the skin thickness of the implant area, resulting in a more elastic and wear-resistant wound formation, less pigmentation and scarring, and ensuring the appearance and function of the limb than a simple blade-thickness flap repair [4-5]. The blade-thickness skin slice is only grafted with epidermis (about 0.20 mm), which causes minimal damage to the site of skin removal, and the epidermis regenerates after one week without forming significant scarring or pigmentation abnormalities. The advantages of VSD are: adequate wound drainage, improved microcirculation, promotion of granulation, reduced wound infection rate, simplicity and speed [6-7]. The VSD was replaced once in 3-5 days during the course of the disease in this group of cases.
In this group of cases, artificial dermis was applied to cover the exposed tendon and small area of bone tissue that were still viable, which achieved good results and increased the scope of artificial dermis application. The healing time of bone exposed wounds with periosteal defects is prolonged, the vascularization time of transplanted artificial dermis is significantly delayed, and the wounds are prone to infection, not easy to heal, and even form difficult to heal wounds [8]. Our experience is that removing the inactivated bone tissue and then transplanting the artificial dermis results in a short vascularization time and a high survival rate of the implant. The artificial dermis is evenly tied with some drainage holes (mesh) during grafting to facilitate negative pressure drainage and make the artificial dermis adhere closely to the trauma [9].
It is believed that the mechanism of artificial dermis repair of wounds with bony tendon exposure is different from the repair of wounds with good substrate, in which the vascular collagenization process starts more at the peripheral tissues of the wound and then gradually invades to the central part, so this method is only suitable for wounds with bony tendon exposure not larger than 10 cm2. However, the applicability of artificial dermis to larger exposed bony tendon wounds with the aid of negative pressure closed drainage remains to be further investigated clinically.
The use of negative pressure suction technique after the application of artificial dermis and blade-thickness skin slice grafting can effectively shorten the surgical interval. Generally, it takes 2-3 weeks for artificial dermis grafting to be followed by autologous skin grafting [11], but in this group of cases, after negative pressure suctioning, the adhesion between the trauma and the graft is better, the drainage is adequate, and the infection rate is lower. This shortens the patient’s hospital stay and reduces the overall cost of treatment.
In addition, some scholars have also reported that artificial dermis has been used for chronic non-healing wounds in diabetes and achieved better therapeutic results. It effectively promotes vascular growth factor and collagen synthesis in the dermis to accelerate diabetic wound healing [12].
In conclusion, the combination of artificial dermis and autologous skin with negative pressure suction for treatment of refractory wounds provides a new option for refractory wounds because of the simplicity of the method, short operative time, high quality of wound healing, short duration of disease, and minimal damage to the donor area [13].