Correction of Scar Contracture Deformity of Dorsal Hand by Invisible Full-thickness Mesh Skin Graft

Hai-qing WANG,Qing-xin XU,Wen-ming LIU,Jia-guang LI,Zhen-zhen WAN,Guang-huai CUI

Department of Burn and Plastic Surgery,Affiliated Hospital of Binzhou Medical College,Binzhou City,Shandong Province,256600,China

ABSTRACT Objective To investigate the effect of invisible full-thickness mesh skin graft in the treatment of scar contracture deformity of the dorsal hand.Methods From January 2016 to February 2019,25 patients with cicatricial contracture deformity of dorsal hand admitted to our hospital underwent full thickness skin graft.During the operation,the scar healed completely and the superficial fascia remained intact.The wound surface was transplanted with invisible mesh full thickness skin graft.The survival of the skin graft and the recovery of hand function and appearance in the later period were observed after the operation.Results The skin grafts of 20 patients survived with high quality,3 cases had partial epidermis exfoliation,and 2 cases had partial epidermis scattered in blisters.After intensive dressing change,all wounds healed and no complications occurred after the operation.The hand function and appearance of the patients were obviously improved.Conclusion The application of full thickness skin graft to correct scar deformity has the advantages of good functional and appearance recovery and difficult postoperative contracture.Invisible full-thickness mesh skin graft is one of the ideal methods to correct scar contracture deformity of the dorsal hand.

KEY WORDS Scar; Invisible full-thickness mesh skin graft; Contracture deformity; Repair

The hand is not only the most used and flexible organ of the human body,but also the part of the body that is most vulnerable to burns.Clinically,hand burns are generally found in dorsal hand burns,because the dorsal hand is often exposed,and the skin on the dorsal hand is thinner and adipose tissue is less[1].After hand burns,patients often suffer from complications such as hypertrophic scar,joint contracture,dyskinesia,peripheral nerve injury,etc.With the progress of medical treatment,more attention has been paid to appearance reconstruction and functional recovery in burn treatment.However,complications such as joint contracture caused by poor recovery of deep hand burns have a great impact on the quality of life of patients and their reintegration into society.[2]Therefore,comprehensive intervention measures such as early scar resection and skin transplantation,joint exercise,scar care and splint fixation are needed for the prevention and treatment of joint contracture.This article will focus on the treatment of cicatricial contracture deformity of the dorsal hand with invisible full-thickness mesh skin graft.

MATERIALS AND METHOD

Clinical data

There were 18 males and 7 females in this group,aged 7-56 years.Scars mainly involve the dorsal hands.Causes of injury:9 cases of electric injury,11 cases of hydrothermal scald,1 case of knife injury,2 cases of machine crush injury and 2 cases of other injuries.The follow-up period ranged from 2 to 36 months,with an average of 12 months.

Surgical methods

Before the operation,the general situation of patients was evaluated,relevant examinations were improved,and surgical taboos were excluded.During the operation,a zigzag incision was designed from the tightest part of the scar on the dorsal hand,to cut the scar tissue to the normal fat layer,completely loosen the scar,trim the surrounding tissues and basement,thoroughly debride,and achieve the purpose of hemostasis.According to the wound surface of the dorsal hand,the model is taken,and the full-thickness skin graft is taken from the waist and abdomen under normal circumstances.For patients with extensive burns,relatively normal and hidden skin should be selected as far as possible in the skin donor area.After finishing the full-thickness mesh skin graft,the whole skin graft was transplanted,the edge was sutured,and the packing and compression fixation were carried out.The skin donor area was directly wooed and sutured,and negative pressure is placed for suction.After the operation,the patient was instructed to immobilize,raise the affected limb,and closely observe the blood circulation at the finger end.Give symptomatic support treatment such as fluid infusion and anti-infection.The dressing was removed 10 days after the operation,to observe the survival of the skin graft,and dressing change and other treatments were given as appropriate to promote healing.Instruct patients to pay attention to sun protection in the out-of-hospital operation area,avoid contact with irritant substances as well as physical activity of affected limbs.Cooperate with functional exercise to prevent contracture.Follow up at 1,3,6,12 and 24 months after the operation.

Fabrication method of invisible full-thickness mesh skin graft

The thickness of the skin reached the subcutaneous fat layer,and the adipose tissue was trimmed to the white dermis layer,with only the fat column visible.After repeated cleaning with normal saline,spread the skin graft on the sterile curved plate with reverse buckle,and the assistant moderately pulls the skin graft to prevent it from retracting.With the aid of a ruler,a 5mm×5mm invisible mesh with a depth of about 0.5 mm was drawn in the dermis layer with a No.11 blade,so that the transplanted full-thickness skin graft was tightly adhered to the wound base.

RESULTS

The skin grafts of 20 patients survived with high quality.3 cases showed partial epidermis exfoliation and 2 cases showed partial epidermis scattered in blisters.All wounds healed after intensive dressing change.The incisions in the donor area healed in one stage without postoperative complications.The follow-up period ranged from 2 to 36 months,with an average of 12 months.Skin grafting wounds are slightly pigmented and flexible in texture.All patients had no skin malignant transformation and no obvious secondary scar.The patient’s hyperextension,hyperflexion,weight bearing and most fine movements could be completed,and the function of the affected limb basically returns to normal.The patients’ hand function and appearance were obviously improved.

TYPICAL CASES

The patient,a 29-year-old male,was admitted to hospital for “2 years of scar contracture of both hands caused by electric injury”.Specialist physical examination:large areas of scar tissue and changes after skin grafting could be seen in the neck,hands and abdomen.Among them,scar contracture deformity of the left hand was more serious,false webs were formed between each finger,thumb and index finger could not be straightened,and scar fracture could be seen on the doral hand without obvious redness and swelling.Pseudowebs were formed between the fingers of the right hand.The degree of scar contracture deformity gradually increased from the ulnar side (little finger)to the radial side (thumb),and the scar had no changes such as ulceration,redness and swelling.Large scar formation,umbilical scar contracture and sinus formation could be seen in the abdomen,with a small amount of secretion (Fig.1).Admission diagnosis:1.Scar contracture (both hands)2.Umbilical scar.After admission,after perfecting relevant examinations and eliminating surgical taboos,two-handed scar resection+ skin flap plasty+left thigh shaping and skin removal+ full thickness skin graft+left thumb Kirschner wire internal fixation+plaster external fixation+umbilicus plasty were performed under static and inhalation combined anesthesia.After successful anesthesia,the scar on the back of the left wrist was removed under tourniquet hemostasis and sent to pathology.The wound surface was about 15.0cm×5.0 cm.Make a zigzag incision at the tightest part of the scar on the first,second and third fingers of the left hand to completely release the scar until the fingers are fully straightened.After cross suture of bilateral flaps between the second and third fingers,a skin defect with a size of about 2.0×2.0 cm was formed in the middle.Sawtooth incision was made at the tightest part of the scar on the 2nd and 3rd finger webs of the right hand,and the scar was completely released until the finger was fully straightened.After the bilateral skin flaps were sutured crosswise,skin defects of about 2.0×2.0 cm and 3.0×2.0 cm in size were formed in the middle,and the thumb of the left hand was extended and fixed with a Kirschner wire.After hemostasis and flushing of the wound surface,the mold is taken from the left thigh according to the size of the wound surface,the skin graft is trimmed and defatted with scissors,and a 5mm×5mm invisible mesh with a depth of about 0.5mm is shallowly scratched on the dermis surface of the fullthickness skin graft with a No.11 blade to promote the survival of the skin graft (Fig.2).In addition,the blade thickness skin graft was grafted into the wound surface of the left thigh,and the dressing was fixed externally and bandaged under pressure.The full-thickness skin graft was transplanted to the wounds between the left wrist back and the left and right fingers,and the edges were sutured,packed and pressurized.It could be seen that the blood supply at the finger end was good,and the left hand was over-flexed and fixed externally with plaster.After cutting the scar in the umbilicus,a foreign body of cotton swab and cotton wool was found in the umbilicus.The scar around the umbilicus was excised extensively.After the wound blood was stopped and the wound was washed,the wound was sutured intermittently,filled with oil yarn and fixed externally with dressing.After 10 days,the packaged dressing was removed and the patient’s skin graft survived well (Fig.3).Follow-up after 1 month showed that the patient’s hand function recovered well,the skin in the skin grafting area was soft,and there was no obvious secondary scar formation (Fig.4).

DISCUSSION

Fig.1

Fig.2

Fig.3

Fig.4

Scar contracture formed after deep second-degree or third-degree burns is easy to cause appearance deformity and dysfunction,especially during secondary healing,because the wound surface does not have normal skin components (such as dermis,blood vessels,etc.).Such wounds healed by scar hyperplasia are more vulnerable to chronic wound and thermal injury.Cytotoxins produced by autolysis and heterolysis of old scars may also cause malignant transformation,such as squamous cell carcinoma,which is the most common malignant tumor in burn scars[3].Skin transplantation is recognized as the best treatment for scar contracture deformity caused by such burns,and is also an important way to prevent scar chronic ulcer and even scar cancer.

At present,medium-thickness skin grafts and fullthickness skin grafts are more common.Medium Thickness Skin Graft (STSG)has a high survival rate,but contracture is easy to occur and its flexibility is poor[4]However,Full Thickness Skin Graft (FTSG)has slight contracture and shows better mechanical and aesthetic effects.However,compared with STSG,the survival rate of FTSG is slightly lower,which could be improved by careful skin trimming and pressure bandaging during the operation[5].Compared with skin malignant transformation rate,functional recovery degree,aesthetic effect,skin quality and scar recurrence,full-thickness skin graft is better[6]Compared with the skin donor area of FTSG,the skin donor area of STSG could be healed by its residual skin accessories,but sometimes there are still problems such as delayed healing,poor aesthetic effect,excessive scars,etc.At present,the main skin donor areas of FTSG are groin area and anterolateral thigh area.The groin area is hidden,but the amount of skin taken is limited.If the tension of direct suture after excessive skin resection is too large,new scars will easily form and the aesthetic effect will be affected.Spindle-shaped incision is formed along the long axis at the anterolateral side of the lateral thigh,and linear scar is formed after skin removal and suture,but this position is not suitable for patients with thin physique.In the process of correcting 25 cases of hand scar deformity,we have a new idea on the selection of skin donor site.The buttocks are rich in fat,the skin is relatively loose,and the amount of skin taken is large.The sutured linear scar basically coincides with the inferior gluteal fold formed by itself,which is more hidden than the inguinal incision.Therefore,this area of inferior gluteal fold is another preferred skin removal area.For example,in case 1,the patient’s groin region could not take skin because the amount of skin taken from the anterolateral thigh was too large to be directly sutured,and the spot skin graft was in the anterolateral thigh region,so we had to remove more skin for “replantation” surgery.In the future,skin could be taken from the subgluteal fold area to solve the problems of large amount of skin taken,high difficulty of direct suture,aesthetic impact,etc.However,it should be noted that the skin supply at this position is not suitable for surgery on instep and other parts,because skin removal in the subgluteal fold area is opposite to the body position required for foot surgery,and it is difficult to disinfect and position during surgery.In addition,surgery is not suitable when the skin in the subgluteal fold area of the patient is too rough.

One of the main reasons for FTSG failure is the occurrence of hematoma under the graft,which leads to poor adhesion,poor vascularization,necrosis and finally graft rejection[5].Full-thickness skin grafts usually go through two stages:serum aspiration stage and vascular reformation[6].The full-thickness skin graft adheres to the basement through the exudation of fibrin from the wound surface,absorbs fibrin-free serum,and begins to grow capillary buds 48 hours later,forming new capillaries that grow into the skin graft.After about 8 days,the blood supply of transplanted skin was stable.we summarized clinical experience to solve the problem of low survival rate of full thickness skin grafts.When trimming the skin flap,we used the No.11 blade to shallowly draw a 1mm well-shaped mesh on the dermis layer of the fullthickness skin flap to form an invisible mesh and increase the contact area between the skin flap and the base.This not only promotes the absorption of serum,but also makes the establishment of blood circulation faster.The survival of full-thickness skin graft mainly depends on the blood supply of wound base,complete hemostasis,good braking and appropriate pressure.The traditional skin graft punching method only reduces the incidence of subcutaneous hematoma by draining and oozing blood,thus improving the survival rate.However,mesh skin grafts fundamentally solve the problem by increasing the contact area of the substrate and promoting the process of serum absorption and vascularization.Hematoma formation could be prevented by complete hemostasis,packing,pressure bandaging,strict braking and other methods during the operation.In actual operation,we found that the control of shallow stroke depth was very important.it is easy for shallow scratching to cut the skin,which is easy to cause contracture and affects the appearance.It is difficult to achieve the expected effect if it is too shallow.This requires that during the meshing operation,the assistant should pull the skin graft properly to keep it in a stable tension state.At the same time,the skin graft should be vascularized evenly with a ruler.Invisible mesh full thickness skin graft is a new idea to solve the low survival rate of FTSG.Through these invisible meshs,the skin graft can fully establish blood circulation with the recipient area.In this paper,25 cases of hand scar deformity correction and other foot dorsum scar deformity correction were repeatedly operated,which proved to be effective and the long-term effect was satisfactory to the patients.Invisible full-thickness mesh skin graft can correct scar contracture deformity on the dorsal hand without special instruments,which is easy to be carried out in primary hospitals.It can restore the anatomical relationship of hand to a large extent,reconstruct the appearance and promote the functional recovery of hand,and is worthy of clinical promotion.At the same time,we also consider whether the difference in mesh depth and area will affect the prognosis.What is the best specification? When the risk of hematoma formation is high,is it necessary to combine skin graft drilling? This is worthy of our further clinical practice and discussion.