The Effect of Fascial Pedicled Island Flap of the First Metacarpal Radial Dorsal Artery Skin Branch Chain on the Repair of Thumb Tissue Defect

Zhan-lei WANG, Hong-liang HU, Wei-jun SHEN,Ji-tao YAN,Jun-wu GONG Hai-yang LIU,Dong-bo LIU

Luohe Second People’s Hospital Microsurgery of Hand and Foot,Henan Province,46200,China

ABSTRACT Objective To analyze the effect of fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain on the repair of thumb tissue defect.Methods take the 100 patients with thumb tissue defects treated in our hospital from 2017.01 to 2019.01 as the research objects,and divide them into control group and observation group randomly,50 cases in each group.In the observation group,the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain is used for repair,and in the control group,the thumb tissue is repaired with abdominal flap.Compare the DASH scores and outcomes of two groups.Results After treatment,the DASH score in the observation group is significantly lower than that in the control group,which is statistically significant (P<0.05); The operation time and intraoperative blood loss of Observation Group is significantly lower than Control Group,which is statistically significant (P<0.05).Conclusion Repairing defected thumb with the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chaint has the advantages of simple operation and easy mastery,and has significant curative effect on patients.It is an effective way to repair partial thumb defect,and worth popularizing.

KEY WORDS the First Metacarpal; Radial dorsal artery; Flap; Thumb Tissue

With the development of handicraft industry,the number of patients with hand injury is increasing significantly,especially the thumb injury.Thumb plays an important role in the hand,which is indispensable for grasping and holding.Only part of the defect will have a serious impact on patients’ life and work.Therefore,the clinical requirements for the repair of thumb soft tissue are more strict.It is not only necessary to restore the appearance of patients’ hand,but also to restore its movement and sensory function to the largest extent[1].This study takes 100 patients as research objects to analyze the application value of the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain to the patients.The details are as follows.

OBJECTS & METHODS

Research Objects

100 patients with thumb tissue defects treated in our hospital from 2017.01 to 2019.01 are taken as the research objects,who are randomly divided into control group and observation group,50 cases in each group.In the observation group,the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain is used for repair,including 33 males and 17 females,with an average age of (45.9±5.7).In the control group,the thumb tissue is repaired with abdominal flap,including 32 males and 18 females,with an average age of (45.6±5.5).All patients in this study are informed and agree to participate in this study,and the Ethics Committee of our hospital has also approved it.There are 36 cases of injury caused by chainsaws,29 cases of machine tool compression injury and 35 cases of machine thermal injury.All the patients have bone and joint exposure after debridement.

Research Methods

In the control group,the thumb tissues are repaired with abdominal flaps,which need to perform local anesthesia on the patient’s abdomen and hands,routinely remove the wounds,repair the edges of the wounds first,and then the abdominal flaps are designed and sutured with wound edges under the condition of no tension.To ensure the flaps are tension-free,the affected thumb should be fixed to the abdomen for 7 days,and the pedicle should be broken after the wound heals.In the observation group,the patients are treated with the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain.In this method,the affected area needs to be thoroughly debrided,and patients with fractures need internal fixation first.The flap should be designed according to the defect range and the distance of the wound surface,and the flap shape should be designed according to the defect area.With the radial or ulnar edge of the injured finger as the axis,the position of the rotation point should not exceed the metacarpophalangeal joint; the distal flap should not exceed the transverse carpal ligament,and the subcutaneous tissue should be incised at the proximal end of flap,and then free the flap;When cutting the flap,it should avoid to damage the skin and subcutaneous tissue and preserve the vessels and nerves in the fascia as much as possible,and the extensor tendon should be avoided to be damaged also; A deep fascia with a width of 1.0-1.2cm should be kept under the flap,and the distal end of the flap should be designed as “water drop”.Loose the tourniquet after flap cutting.Then repair the wound after the blood supply returns to normal and the flap becomes ruddy.Lift the flap to the plane of the rotation point to cover and suture the wound.During the suture,the tension should not be too large,so as to avoid affecting the flap’s blood flow.If the flap’s width is less than 1.5cm,it can be sutured directly.But if it is more than 1.5cm,split-thickness skin graft should be chosen for skin grafts.After operation,the patients should be given dressing change,antibiotics,pit coagulants and painkillers on time.The temperature of the ward needs to be appropriate.The skin flap temperature,skin color and swelling of the patients should be paid close attention to.If there is any abnormal situation,timely management is essential.

Outcomes

1.Observe the DASH scores of two groups.The lower the score,the better the patient’s function recover.

2.Observe the operation time,intraoperative blood loss and other surgical indicators of the two groups.

RESULTS

Comparison of DASH scores between two groups

After treatment,the DASH score in the observation group is significantly lower than that in the control group,which is statistically significant (P<0.05),as detailed in table 1.

Comparison of surgical indicators between two groups

The operation time and intraoperative blood loss of Observation Group is significantly lower than Control Group,which is statistically significant (P<0.05),as detailed in table 2.

DISCUSSION

The defect of distal thumb will seriously affect the pinching function and picking ability of fingers,which will bring great trouble to patients’ work and life.Therefore,it is of great significance to repair the thumb defect[2-3].At present,there are many surgical schemes for the repair of thumb soft tissue defects in clinic,and theefficacy of each method is different[4].In the early stage,there are fewer skin tissue defects at the last segment,and patients’ bone is usually exposed,so if the patients need to keep the finger length,abdominal flap repair is usually adopted,in which the second-time flap short pedicle surgery is required.The operation will be limited to the abdomen,which will lead to the corresponding restriction of the defected fingers’ activity,joint stiffness and other such situations,which will increase the pain of the patients.Because the recipient site is small,the flap’s thickness of the donor site is large,and the skin’s color difference between the donor site and the recipient site is more obvious,it may have overstaffed appearance and large color difference after the flap survives.And because there is no nerve growth,it may increase the discomfort of the patient.In winter,the discomfort is more obvious.After physical labor,the skin flap in the affected area is extremely prone to wear and tear,which will also reduce the patients’ satisfaction[5].With the development of microsurgery technology,toe transplantation for finger tissue defect comes into being.The operation is relatively successful,and it has a significant effect on the recovery of the appearance and function of patients’ defected finger.However,there are certain risks of this operation mode,and the fear of unknown risks makes it difficult for most patients to accept this operation mode.What’s more,the area of hand defect is relatively small,and if part of the toes are transplanted to the hand,most patients may think that it is overqualified.At the same time,this kind of operation has stricter requirements on patients and doctors,so it is not easy to promote in primary hospitals[6-8].

Table 1 Comparison of DASH Scores Between Two Groups

Table 2 Comparison of Surgical Indicators Between Two Groups

In recent years,the repair of surgical wounds has gradually developed to proximal nerve repair and local bag pedicle flap.The main principle of flap repair is “the recipient area is well repaired and the donor area is less damaged”[9].It has been suggested by some scholars that the dorsal fascial pedicle flap,which uses the reticular vessels connecting the digital arteries and dorsal digital vessel as the basis of blood supply,is a kind of fascial pedicled flap with great arbitrariness,so it can be used to repair the defects of various parts of fingers.The main source of blood supply for the fascial pedicled island flap of the first metacarpal radial dorsal is the capillary network of the deep fascia in the corresponding area of the flap.Because the flap carries the fascial pedicle,and the fascia pedicle is mainly composed of the cutaneous nerve and the dense vascular network around superficial vein,thus a directional vascular plexus is created,which provides the blood circulation for the flap and makes the flap can carry out venous reflux by direct reflux and labyrinth reflux.In clinical practice,different blood supply mechanisms are usually selected according to the patients’ thumb and thumb soft tissue damage[10-11].The blood supply of the dorsal fascial island flap of the first metacarpal bone is very sufficient,which can basically cover the defect of thumb without having to cut the extensor tendon or dissect the dorsal metacarpal vessels.Moreover,the texture of the flap is relatively soft; the thickness is moderate; there is no obvious color difference between recipient site and donor site and the thickness of flap is less than 1.5cm which can be directly sutured.The only deficiency is that there may be some different degrees of scars left on patients’ hands back[12].

The advantage of this flap is that it will not cause damage to the proper artery and the proper nerve of the finger,and the effect on the sense and function of the patients’ defect finger is relatively small.There are arterial cutaneous branch vascular network and cutaneous nerve in the flap,which has strong anti-infectivity and higher survival rate after the operation,and the numbness or frostbite won’t happen in winter.There is a abundant venous network at the fascia.And the pedicle of the fascia is short,so after opening the tunnel,the venous return can be guaranteed.The small area helps to improve the survival rate of the resected flap.As long as the operation is standardized and the patients’ blood circulation after operation is good,there will be small incidence of arterial insufficiency and venous crisis,and no flap necrosis will happen[13].The extent of the operation is mainly on the hand,and the resection area is small,which will not tend to cause the patients to be injured again.After the operation,there is no need to use plaster for fixation,and the patients can do early functional exercises to help restore the mobility of fingertip joint.The texture and color of the flap are similar to those of the surrounding tissue,and no significant swelling.Normally,there is no need to repair again after the operation,and the blood supply can be in good condition,which can meet the needs of patients’ daily life to the largest extent.The disadvantage of the flap is that the donor area is very limited,and it cannot meet the trauma with a large injury area[14].The nerve in the flap are mainly cutaneous nerve,so there may be some differences when compared with the normal contralateral fingertips after operation.The donor and recipient areas of flap may have adhesions after healing.Patients need long-term functional exercise and local massage to recover.It should be noted that when the flap is smaller,it should be closer to the pedicle as far as possible so as to avoid interruption of the cortex chain.If the flap is larger,there is no need to worry.The pedicle should be loose,not strained or compressed,and the aponeurosis of the affected area should be preserved when the flap is separated,so as to avoid adhesion with tendon if the skin graft is fail and the effect on the flexion and extension of the affected finger[15].

The following points should be noted when treating patients clinically

A comprehensive assessment of the damage degree of patients’ hands should be performed before operation so as to ensure the effectiveness and integrity of the vascular network on the back of patients’ hands.

Good microsurgical operation is an important condition to ensure the success of operation.Non-invasive operation should be taken as much as possible,so as to preserve the nerve tissue and blood vessels in the fascia to the largest extent.

It is necessary to pay attention to the design of the points,lines and face of the flap.The metacarpophalangeal joint should be used as the rotation point,the free plane should be between extensor tendon and deep fascia,and the distal end of the flap should not exceed the transverse carpal ligament.

The flap will be atrophic after being dissected,so the flap area should be 10% bigger than that of the wound,so that the wound can be well covered.The shape of the flap should be consistent with that of the wound,and the deep fascia with a width of 1.0-1.2cm is the best choice.A small amount of pedicles should be reserved in the proximal part of the pedicle.Designing it as a “water drop” can reduce the tension of the flap to a certain extent.

The pedicle of the flap should maintain an open channel and fully separate the subcutaneous tunnel so that it can easily accommodate the whole displaced nerve vessel,avoiding vascular torsion or pulling.If it is difficult for the flap to pass,the tunnel can be cut open and sutured after the flap has been transferred.The flap pedicle should be prevented from being squeezed so that the blood supply can be normal.The pedicle should be sutured without tension.And the needle spacing should not be too tight or too sparse and attention should be paid to whether there is compression,torsion and other such conditions during suturing.After operation,it is necessary to carefully observe the blood circulation of the flap and pay close attention to whether there is any abnormality.If there is any abnormality,relevant treatment measures should be given in time to ensure the smooth survival of the flap.

In this study,the DASH score of the observation group after treatment was significantly lower than that of the control group,and the operation time and intraoperative blood loss were significantly less than that of the control group.The research data of the two groups are of statistical significance,suggesting that the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain can help to promote the patients’ defected thumbs to recover as quickly as possible,shorten the operation time and have higher security.

To sum up,the fascial pedicled island flap of the first metacarpal radial dorsal artery skin branch chain has a significant effect on the treatment of thumb defect.Because the texture of the dorsal region of the first metacarpal is similar to that of the thumb skin,both of them have stable blood supply form and same surgical field of vision,and the operation is simple and convenient,so it is an effective way to treat such kind of patients,with high value of use,which is worthy of further promotion in clinic.