Study on Different Types of Skin Flap Transplantation to Repair Forefoot Damaged Injury

Jian-yun XU,Xin-lei YANG,Bao-kai CAI,Jin-hu LI

Department of Burn and Plastic Surgery,174 Hospital of the Chinese People’s Liberation Army,Xiamen city,Fujian Province,361000，China

ABSTRACT Objective To investigate the clinical effect of different types of skin flap transplantation in repairing forefoot lesion.Methods From January 2016 to June 2019,62 patients with forefoot damage were selected and their clinical data were retrospectively analyzed.All the selected patients received skin flap transplantation and repair,of which 26 patients received free myocutaneous flap transplantation and repair,and were treated as group A.The other 36 patients underwent retrograde foot flap transplantation and repair.They were taken as group B,and the clinical treatment methods and curative effects were summarized.Results Among the 26 patients in group A,the skin flaps of 21 patients survived completely,while those of the other 5 patients showed partial necrosis at the edge of the skin flaps.They were treated with free skin grafting and healed after regular dressing change.All the skin flaps survived.Follow-up for at least 6 months showed that 11 patients had mild claudication and skin flap sensation was slightly poor.Among the 36 patients in group B,only 2 cases suffered from distal partial necrosis after the operation,which was caused by large tension after dorsum pedis flap transplantation.After systematic treatment and regular dressing change by doctors,the flaps of 2 patients healed.In addition,venous reflux disorder occurred in 3 patients with medial saphenous nerve nutrient vessel flap of the foot,which was related to swelling factors.The flaps of other patients survived,healed well and did not show infection symptoms.Conclusion According to the actual condition of patients with forefoot damage,the flap repair method is formulated,which has good short-term and long-term therapeutic effects and plays an important role in repairing forefoot damage.

KEY WORDS Skin flap transplantation; forefoot lesion; Flap necrosis; Free skin grafting

Forefoot lesion is a common disease in the burn department.There are many factors leading to injury,such as smashing injury,crushing injury,traffic injury,etc.,which have a serious impact on lower limb function.Flap repair is currently a common clinical treatment method.Accurately judging the patient’s condition and carrying out corresponding treatment on the patient can effectively improve the diagnosis and treatment effect of the patient,improve the condition,relieve pain and promote the recovery of foot function[1].62 patients with forefoot damage were selected as observation objects,and different types of skin flap transplantation treatment methods were analyzed to summarize the clinical treatment.The report is as follows.

DATA AND METHODS

General information

The clinical data of 62 patients with forefoot damage from January 2016 to June 2019 were retrospectively analyzed.The selected patients meet the research conditions of this subject and meets the standards and indications of skin flap repair and treatment[1].The research content meets the ethical standards.

Inclusion criteria[2](1)Understand the treatment plan of this study; (2)Sign the informed consent form; (3)All patients were over 18 years old; In this group,51 patients were male and 15 patients were female,aged 23-58 years,with an average age of 38.47 3.58 years.Causes of injury:23 cases of traffic injury,18 cases of crush injury,12 cases of smash injury,5 cases of cutting injury and 4 cases of other injuries.The operation timing of this group of patients:53 cases of emergency operation and 9 cases of sub-emergency operation.Among them,26 patients underwent free myocutaneous flap transplantation and repair,and were set as group A,while the remaining 36 patients underwent retrograde foot flap transplantation and repair,and were set as group B.

Exclusion criteria[3-4]:(1)Acute and chronic infection; (3)Patients with contraindications to surgery; (4)Patients with hematological diseases; (4)Patients who cannot cooperate with treatment; (5)Drug allergy.

Treatment

(1)Group A:Patients in this group received free myocutaneous flap transplantation for repair.Cut the anterior half of the foot injury,timely remove the deactivated soft tissue,trim the skin edge,and remove the metatarsal bone (severed)in the distal segment of the foot.After trimming,Kirschner wire was used to treat the stump of the 1st to 5th metatarsal bone and complete internal fixation.The articular cartilage of the five metatarsal heads needs to be removed and flattened.The three-point weight-bearing structure of the sole and the three-arch structure of the foot were preserved,and the transverse branch and descending branch of the lateral circumflex femoral artery combined with myocutaneous flap were selected.The area of the skin flap was 16*26 cm.The skin flap was transplanted to repair the soft tissue defect of the right forefoot.The distal end and sole of the skin flap were sutured at the proximal skin edge,then 180-degree reversal was carried out around the dorsal side of the metatarsal head.The pedicle end and the proximal skin edge of the foot were sutured,the lateral skin edge,the foot bottom and the back of the foot were sutured,the metatarsal bone is embedded,and the wound surface was sealed.The vascular pedicle artery of the flap was anastomosed with the stump of the dorsal pedis artery,and the two veins were anastomosed to suture the cutaneous nerve and the medial dorsal pedis nerve.It is necessary to strengthen the observation after the operation.If complications occur,symptomatic treatment is required.

(2)Group B:The patients in this group underwent retrograde foot flap transplantation and repair,and the wound surface was thoroughly cleaned up.The wound surface condition was determined according to the injury condition of the patients.The midpoint of the medial and lateral malleolus connection line and the midpoint of the first toe web connection line were taken as the axis line for treatment,the deep plantar branch of the flap was taken as the pedicle,and the deep plantar branch at the proximal end of the gap between the first metatarsal bone and the second metatarsal bone was taken as the penetrating point.The first dorsal metatarsal artery was used as the pedicle,and the first dorsal metatarsal artery was connected with the first toe web and the free edge at a distance of 1.5 cm.The point of rotation was any point in the middle of the line.The flap was designed on both sides,and the proximal vascular ligation was used as a blocking experiment to ensure its blood supply.After resection,the flap was rotated 180 degrees and the recipient area was sutured.The axial line of the flap was consistent with that of the dorsum pedis flap.The gap between the first metatarsal bone and the second metatarsal bone ran along the dorsal artery and was 1.5 cm apart from the free edge of the first toe web.From the medial side to one third of the skin on the medial edge of the foot,the flap was designed according to the central axis where the recipient area was located.The rotation point of the flap was the medial side of the middle segment of the first metatarsal bone.The flap area was 9.1cmx7.8 cmx8.5cm.The medial thigh medium thickness skin flap was used as the graft,and the skin flap was cut and transplanted according to the patient’s condition.If the flap is pedicled with the deep plantar branch,the surgical rotation point can be determined in the metatarsal (first and second)space.Both sides were side-opened to accurately design the skin flap.Before ligating the proximal blood vessel,a vascular occlusion test was required to avoid blood supply problems.The flap was turned over under the fascia so that it could cover all the defect positions of the foot.After all operations were completed,the blood supply was observed.Conventional suture of the wound margin,skin flap,skin graft,skin flap pedicle,etc.were bandaged and fixed by the compression method[5].

Evaluation Indicators

The clinical treatment of group A and group B patients was analyzed and summarized,and the survival status of skin flaps in the two groups was counted.The followup time of the two groups of patients was at least 6 months,and the situation during the follow-up period was summarized,including complications,pain,healing,etc.,and detailed records and statistics were made.

RESULTS

Treatment Analysis of Group A Patients

(1)Survival status of skin flap:This group of patients showed obvious skin flap swelling within 3-5 days after the operation,and some patients had blisters on their feet.Among the 26 patients in group A,the flaps of 21 patients survived completely,while the flaps of the other 5 patients showed partial necrosis at the edge of the flaps.The flaps were treated with free skin grafting and healed after regular dressing change.All the flaps survived.

(2)Follow-up analysis:The follow-up period was at least 6 months.11 patients suffered from mild claudication and had slightly poor flap sensation.The rest of the patients recovered well without soft tissue coverage and foot function recovered well.

Treatment Summary of Group B Patients

(1)Flap healing:Among the 36 patients in group B,only 2 cases suffered from distal partial necrosis after the operation,which was caused by large tension after dorsal pedis flap transplantation.After systematic treatment and regular dressing change by doctors,the skin flaps of 2 patients healed.In addition,venous reflux disorder occurred in 3 patients with medial saphenous nerve nutrient vessel flap of the foot,which was related to swelling factors.The flaps of other patients survived,healed well without infection symptoms.

(2)Follow-up analysis:The patients in this group healed well,no serious infection symptoms occurred during the follow-up,and the patients walked normally,basically without pain and skin ulceration.

Typical Cases

Mr.Liu,male,28 years old,suffered a serious injury to the front half of his right foot.He was diagnosed with multiple metatarsal fractures.Nearly one third of the fractures were severed and only part of the flexor tendons were connected.During the operation,the injured part of the right foot was cut off,the soft tissue that had lost its vitality was removed,the skin edge was trimmed,and the metatarsal bone (broken)at the distal end of the foot was removed.After trimming,Kirschner wire was used to fix metatarsal stump (1-5 segments),and the arch structure and plantar three-point weight-bearing structure of the patient were preserved.Then,the transverse branch and descending branch of the lateral femoral circumflex artery was combined with myocutaneous flap,the proximal plantar and distal skin margin of the flap were sutured,and the dorsal part of the foot was sutured to the plantar position of the lateral skin margin.After stump anastomosis,the metatarsal bone was embedded to observe the wound surface and suture the wound surface after no problem was found.

DISCUSSION

The probability of foot injury is relatively high,and especially the anterior foot injury is more common,which is mainly caused by violent factors and can lead to serious skin and soft tissue injury,usually accompanied by metatarsal and phalangeal fractures,and mostly multiple comminuted fractures[6,7].

Under normal circumstances,in the clinical diagnosis and treatment of patients,for patients complicated with comminuted fractures,it is necessary to thoroughly debride the broken end of the fracture,and then fully fix the base of the metatarsal bone to expose the distal bone[1].In this study,26 patients were treated with free myocutaneous flap transplantation and 36 patients were treated with retrograde foot flap transplantation.The results showed that both methods could exert obvious effects,and the survival rate of skin flap was relatively high.There were no serious complications after follow-up and the foot function recovered well.Some literatures[8,9]believe that free skin grafting,suture and internal fixation can play a good therapeutic role in patients,but for patients with serious plantar and dorsum injuries,it can lead to a large amount of skin necrosis in this part,lead to difficulty in wound repair,and bring serious impact on the physical and mental health of patients.Another study in[10,11]found that according to the patient’s condition,the appropriate skin flap repair method should be selected.Generally,the maximum cutting area of skin flap can reach 10*45cm,and the minimum area of skin flap is 8*10cm.The survival rate of skin flap is relatively high,but the edge of the skin flap is prone to necrosis and can heal after free treatment,which is basically consistent with the results of this study.

If the integrity of the first metatarsal bone needs to be protected,it should not be shortened easily.Skin flap transplantation is required for patients with skin defect and bone exposure.If the first metatarsal bone is cut off,the transverse arch will lose its support,the medial longitudinal arch will be incomplete,and the sole of the foot will lose its mechanical foundation,thus losing its weight-bearing capacity.There are four kinds of retrograde skin flaps,which have the characteristics of abrasion resistance,less subcutaneous fat,thick stratum corneum and compact subcutaneous tissue,The dorsal pedis flap has the advantages of easy anatomy,reliability,long pedicle and convenient use.However,the donor site requires higher wound coverage.Improper treatment will affect the foot function and shoe wearing,and the main artery will affect the foot function.It is mainly suitable for patients with exposure of the first metatarsal bone and forefoot damage,but it cannot be applied if the patient’s first dorsal metatarsal artery and deep plantar branch are injured.The first dorsal metatarsal artery flap does not sacrifice the main artery,but the flap has a relatively small range and is mainly suitable for patients whose first dorsal metatarsal artery and first toe web are not damaged.Half of the rotational avulsion injury is applied to the first dorsal toe artery,while the first plantar artery anastomosis injury is not suitable for the application.The medial plantar flap has the advantages of flexible transposition,non-weight-bearing area,non-main artery,hidden location,long pedicle and no influence on appearance and function,and it can be used as a better donor site for repairing injuries of the first metatarsal bone and forefoot.However,due to its dense subcutaneous tissue,it is not suitable for extracting tunnels and needs to be transferred from open tunnels.The medial saphenous nerve nutrient vessel flap of the foot has the advantages of convenient operation,superficial branches of medial vessels,nonweight-bearing area,constancy and non-main vessels.However,the free vascular pedicle needs to cut off the tibial anterior tendon and be fixed for 3-4 weeks after the operation,which is mainly suitable for patients with large area injury and first dorsal metatarsal artery injury.In the process of treatment,complete debridement should be carried out without necrotic tissue.Otherwise,the wound of the patient is difficult to heal after the operation,and the necrotic tissue is likely to lead to complications such as tissue inability to transplant and flap necrosis.The skin flap is a normal tissue,which will cause damage to the connected blood vessels during rotation and avulsion.Therefore,it is necessary to use the skin flap pedicled with the first dorsal metatarsal artery,and the saphenous nerve vascular skin flap and dorsal foot skin flap need to be carefully selected for crush injury.Open tunnel transfer is required for tunnel opening and postoperative treatment to avoid pedicle pressure caused by dense skin tissue and connected fiber intervals on the foot.After the operation,the swelling condition of the skin flap needs to be observed.When necessary,sutures need to be removed to relieve the compression condition of the pedicle and ensure the safety of the skin flap.

In actual work,efforts are made to protect the integrity of the first metatarsal bone.For patients with skin and belly defects.The corresponding skin flap transplantation and repair can provide a better transverse arch support foundation,preserve the plantar three-point support structure,and improve the weight-bearing capacity of the injured foot.In the process of skin flap repair,the above-mentioned retrograde skin flap repair method has less subcutaneous fat,thick stratum corneum and high wear resistance[12].Generally speaking,the blood vessels of the dorsum pedis flap are relatively reliable and can be convenient for anatomical operation,so it is more convenient to use.However,the repair of retrograde foot flap also has certain shortcomings.First,the operation requires high wound coverage.If the treatment is unreasonable,it will have a serious impact on the recovery of foot function.Second,the scope of the skin flap is relatively small,and the scope of application is restricted to some extent[13].

Based on the above analysis,it is believed that no matter what kind of skin flap repair method is adopted,it is necessary to accurately judge the patient’s condition,combine multi-disciplinary knowledge,do a good job in consultation,formulate the best repair method for patients,and promote the improvement of skin flap repair effect.The above two repair methods have obvious effects,but have certain treatment indications.A comprehensive analysis of patients is needed to ensure that the repair shape of the flap reaches the satisfaction of patients and maintains good blood supply.After treatment,the patient scan walk with a heavy load through certain rehabilitation.Literature[14]suggests that the anterolateral thigh flap has a large cutting area and provides good blood supply,and is more suitable for repair and treatment of forefoot damage.