The Anatomical Basis For Designing And Clinical Application Of Medial Pedis Perforator Flap

Background:With the society’s development of transportation and industry,more and more people suffered hand and foot injuries.Hands are important tools for people to engage in productive labor,and an integral part of beauty.They are also important tools for exchange of human emotions in social life.Foot is the weight-bearing part of the body. Limbs trauma often results in bone and tendon exposing,blood vessels and nerve damaging. If these injuries were not handled properly,the bone and muscle necrosis, infection may be present,and finally face the risk of amputation.It will not only affect the injured person’s daily life,working and learning,but also scaring then in their spirit and psychology.The soft tissue defects of hand and foot often needs skin flap for repairing of them. Skin of the palm and sole is thicker in stratum corneum,more durable,smooth and have dermatoglyphical characteristics.The are many requirements of repairing of hand and foot soft tissue defects:(1)The texture and color of skin should be similar to the district.(2) The thickness of flap should be appropriate, the bloated flaps not only affect the appearance but also function.(3) The feeling of flap can recover as soon as possible.The traditional forearm flap,groin flap,femoral anterolateral flap,flap pedicled with peroneal artery, can’t meet the requirements in texture,features, functions, and feeling.Since1979Shanahan first reported the the clinical application of the plantar medial flap, this flap had caused widespread concern, and was considered to be an excellent alternative in the reconstruction of complex skin defects of plantar foot,because of its texture, sensory recovering and concealment. Since then,with the rapid development of microsurgy techniques, the basis for its further application of surgical and clinical studies are constantly deepened. Since many years ago,the medial plantar flap was vascularized by the medial plantar artery and its branches.It belongs to the traditional axial vascular flap,cut often need firstly expose posterior tibial artery,then anatomise the medial plantar artery and its branches anterogradely. Traditional methods of harvesting flaps need deep-seated anatomy,caused more injuries to flap donor site,and the operative time is longer,bring more pain to the patients. Additionally because of the presence of medial plantar artery variations, anatomical separation process is easy to lead branch damage,affecting the blood supply of the flap.In2001, Koshima introduced the concept of perforator flap to the medial pedis area,further reducing the damage to the doner site. Later,many scholars have conducted researches on the operative design of medial pedis flap. At present,the medial pedis pefofator flap is widely used for the repair of soft tissue defects on the volar foot and hand. The design of flap is based on anatomical basis,although numerous publicatons have addressed the application of medial pedis perforator flap, few have addressed the surgical flap anatomy with clarity. This,along with the substantial anatomical variation of the region, might underlie the low use of this flap in clinical practice.Thus,the anatomical basis of medial pedis flap deserve further research effort. To provide anatomical data for clinical application of perforating flap. Traditional anatomical methods such as autopsy and cast specimens,can be observed the location of the skin perforators, rough estimates of the supply of blood.But it takes longer time to anatomise and is destructive. Cadavers can not be repeated used. With the development of digital human and virtual reality technology, three-dimensional visualization of the angioarchitecture of flaps become a hot topic. Which provides a new research method for perforator flaps-today’s new development in microsurgical flap. So far, many perforator flaps (eg anterolateral thigh perforator flap, submental artery perforator flap, the inferior epigastric artery perforator flap, posterior interosseous artery perforator flap, dorsal metacarpal artery perforator flap, peroneal artery perforator flap, etc) were studied with digitized three-dimensional visualization technology. Reconstructed three-dimensional models can accurately reflect the anatomical structures of the flaps,and be rotated to display the angioarchitecture of flaps from different perspective. Digital3D reconstruction techniques made the flap anatomy changing from static to dynamic, two-dimension to three-dimension.In clinic,the preoperative flap design mainly rely on surgeon’s experience,roughly estimated the location,diameter of the vascular pedicle,and the size of flap,that’s not only increases the difficulty of the surgery, but the high risk of perforators damage.It will significantly improve the quality and reliability of the flap operation,if the flap donor site reconstructed by three-dimensional visualization before operation and accurately determine the location,distribution of the vascular pedicle,thus to develop personalized flap reconstruction. Although there are Doppler ultrasound detector to help locate the perforators currently,but its limited probing depth and area, and susceptible to interference, make it difficult to obtain enough preoperative information to perforator vessels. Therefore,it will be of momentous significance in reconstructing three-dimensional imaging of the flap vascular system with digital flap visualization technique, to observe the informations of perforators. In these studies,taking the advantages of microdissection combined with three-dimensional reconstruction techniques,homologized anatomic data was obtained from fresh corpse foot specimens and three-dimensional models through observation and measurement, to explore the blood supply characteristics in medial pedis non-weight-bearing area.In order to provide anatomical basis for the preoperative design of medial pedis flap, models for surgical planning, simulation and anatomical teaching. In clinical,choose appropriate cases using different types of medialis pedis flaps in the reconstruction of skin defects of the hand-foot,to summarize the indications of clinical applications, advantages and disadvantages of the repair effect.Objective:1. To explore the blood supply of non-weight-bearing area in the plantar foot,to offer anatomy basis of the clinical application of medial pedis flap.2. To discuss the three dimensional reconstruction of angioarchitecture of the medial pedis flap,and to establish their digitized visible models.3. To summarize the disect methods,indications of clinical applications, advantages and disadvantages of the medial pedis flap.Methods:1. Microsurgical anatomy of medial perforator flapThe quantity,length,origin,outside diameter and anastomosis of the perforator of medial plantar artery which were sent out to the area of medial pedis were observed and measured on8adult fresh lower limb specimens perfused with red latex. Using digital camera to records the anatomy course, the results of the datas measured were entered into the computer. The average value was represented by mean±standard deviation.2. Three-dimensional reconstruction of medial pedis perforator flap The selected fresh adult cadaver was perfused with gelatin-lead oxide, which was modified by Tang maolin. The foot-ankle was scaned with64-slice spiral CT, scan parameters:120KV,300mA, thickness0.5mm, matrix512x512. The data is stored in a disc by DICOM format. Enter the DICOM format datas into personal computer by mimics10.01software,reconstructing the medial plantar artery,anterior medial malleolus artery and medial tarsal artery.The perforators’ position,distribution and anastomosis were observed.3. The clinical applications of medial perforator flapFrom January2012to February2014,there were18patients accepted the surgry with medial pedis flaps in the reconstruction of skin defects of the volar hand and foot:6forefoot skin and soft tissue defects, wound size3cm x4cm～5cm×7cm, repaired with hallux toe tibial artery perforator pedicled retrograde transposition;5heel soft tissue defects, wound size4cm x5cm～6cm×8cm,repaired with the superficial branch of the medial plantar artery pedicle transposition repair;7volar digit soft tissue defects, defect size2cm x3cm～3cm×5cm, repaired with free perforator flap.10cases of emergency repair,8cases of asia emergency repair.Results:1. The blood supply of the medial pedis area includes medial plantar artery, medial anterior malleolar artery, medial tarsal arterie and toe tibia lateral artery.The superficial branches of medial plantar atery goes through the deep of abductor hallucis and traveling to subcutaneous near the navicular tuberosity,with the external diameter (1.08±0.20) mm, lenth of pedicle (2.05±0.71) cm. Averagely5.3perforators were identified in the medial intermuscular septum between abductor hallucis and flexor digitorum brevis, which were sent out to the non weight bearing area of medial plantar, average external diameter (0.63±0.25) mm, lenth of pedicle (0.93±0.31) cm. The medial branches of medial plantar deep artery sent out cutaneous branches to the medial pedis area at (1.92±0.61)cm ahead of Scaphoid tuberosity. The tibial artery of hallux go through to the medial pedis area at(2.03±0.56)cm proximal of the fist plantar toe joint, average external diameter (0.6±0.14) mm, lenth of pedicle (2.36±0.42) cm.The arterial arch at the superior border of the hallucal abductor,constituted by superficial branches of medial plantar artery, medial anterior malleolar artery, medial tarsal arterie and toe tibia lateral artery. The venous drainage system of the medial pedis flap includes deep concomitant veins and subcutaneous veins.There were2veins accompanied with medial plantar artery, the perforator veins’ diameter (0.31±0.04) mm, and the diameter of subcutaneous superficial veins usually greater than1.0mm.2. The anatomical structure of foot can be clearly observed through three-dimensional reconstructed image. The angioarchitecture of medial pedis flap showed distinctively, the position of each artery, branches and adjacent distribution relationship has been displayed well.It could display perfectly the main structures of flap and other adjacent structures.3.16flaps were completely survived, in2cases (1of reconstruction in heel soft tissue defect,1of reconstruction in forefoot soft tissue defects),a small portion of the flap edge necrosis occured, through resect the necrotic tissue and dressing treatment,the wound healed. After3-9months’follow-up.The texture, is very good, the color is similar to the target area skin.what’s more,there were different degrees of sensory recovery.Conclusion:1. The medial pedis perforator flap can be designed as pedicle flaps resurfacing defects around the heel and forefoot,and free perforator flaps resurfacing defects of volar digits.2. The three-dimensional visualization of human anatomy could achieved by digital technology. It provides new tools for research and clinical anatomy teaching and visual reference for clinical flap surgery personalized design,increased the reliablity of operation.3. The medial pedis perforator flap is an excellent alternative in the reconstruction ofcomplex volar skin defects of the digits and plantar.The advantages are concealed donor site, appropriate thickness, consistent, similar skin color and satisfactory repair effect.