A 3D Microdissection Study And Clinical Application Of Perforating Flap In The Perineum

[Background] The problem of correlated anatomy and physiology was raised, with the development of autografting and repairing skill on perineal position. The new development of perforating flap in area of microsurgery flap transplantation is accord with tissue transplanting principle:the recipient site is being repaired well, the donor site is being destoried little. The aim of 80 percent clinical flap planting is to cover super skin and soft tissue,only a little is to obdurate dead space or deep part defect. So the perforating flap which contains subcutaneous fat and skin is accord with―what short of what make up for‖. The perineal perforating flap is located between anodic interfemus and perineal region . It is bounded by superior border of pubic symphysis above, ischial tuberosity line below, the lateral border of scrotum or labium majus outside, and medial femoral plica inside. The area is from the lateral border of scrotum or labium majus to endo- anodic of upper leg extend 6cm. The anatomy study of flap is often retented 2D lever in our country or abroad. Yet realy 3D study which can guide clinical operation is little to be reported. The reason is that deficienting of anatomy materials, not well operating skill, and anatomy breaking away from clinic etc. The operation to repair and reconstruct perineal defect is difficult. The perineal perforating flap is ideal flap to do this work because of special anatomia position and plentiful blood supply. Nevertheless the key to design perforating flap and anticipate effect flap area is based on detailed anatomic form. Now the reason of few application of perineal perforating flap is that much study of base of microanatomy not be certained.Such as the number and courser of perforating vascular;the group of vascular anastomotic;the company venous return;and the neurocutaneous distribution and domination. Yet this study need sutible microanatomy technique and microinstrument; microscope. After clinical application of this flap to repair and rebuilt perineal position,we still find that part or total flap necrosis,region dysnemia and feeling diference etc. Therefor ,it is important for us to know the microanatomy study of perineal perforating flap so that we can do better to design and make operation. The study is based on perineal axial our division professor Guo En Tan in 1990. We identify the main perforating branch in perineal, anastomotic vascular net,venous return,cutaneous nerve innervations. Then we can design and apply the perforating flap according with them, and we also provide an new way to study other flap.[Objective] The aim of study is to determine position, quantity, caliber, peduncular length, original vessels, and supply dermatic area of the main perforating branch by perineal region's vessel qualitation and quantitative assay, especially in vessel anatomic basic of perforating branch flap. We can design and applicate perforating branch flap by these study.[Materials and methods] Eleven adult cadavers (22 sides) fixed in 10% formalin were used in this study. Red latex was infused via the radial artery and external iliac artery using a modified lead oxide-gelatin infusion technique. Cadavers were dissected under an operating microscope (*10). Structures of interest were measured using a sliding caliper (accurate to 0.2 mm). We recipe flap on cadaver like clinical operation to find and observe perforating vascellum and cutaneous nerve, then we still our work to find some of them in deep part and confirm where do they come from. All anatomtic struction should be located and quantitative study,the results should be analysis by computer software.We design flap by thigh perineal drain in patients'perineal position. The border of the examined area was: superior: 1.5cm above the superior margin of pubic symphysis; inferior: the imaginary line between the two ischiadic tuberosities; medial: the lateral margin of the scrotum (labium); and lateral: interfemus plica. We recipe skin and hypoderm, then lift flap up deep fascia from down to up. The stem and tissue surrounding of flap should be preserved. We transfer the flap from donor site to recipient site. The donor site can be sutured directly.[Results] There were 4 relatively constant perforating arteries in the perineum: inguinal and perineal perforating branches of the superficial external pudendal artery, a perforating branch of the anterior cutaneous branch of the obturator artery, and a perforating branch of the lateral branch of the posterior scrotal (pudendal) artery. All four arteries were direct perforating branches. These perforating arteries and accompanying veins overlapped with each other and formed the upper, middle and lower parts of the vascular anastomosis in deep fascia above the adductor wall. There were four important cutaneous nerves in the region originating from the following nerves: the genitofemoral nerve, ilioinguinal nerve, posterior scrotum (labium) major nerve, and rami perineales nervi cutanei femoris posterioris. The current study revealed that the upper, middle and lower perineum are supplied by distinct groups of perforating arteries, but with extensive chain type anastomosis network. Based on this finding, we propose the following strategy in designing perforator flaps: To repair the suprapubic region or distal tissue loss, the flap pedicle should be superiorly located and contain the inguinal and/or perineal perforating branches of the superficial external pudendal artery, the recipe deep of the flap stem should be keep 1.55～1.65 cm and tissues below it can be repaired thin to 0.90～1.00cm, the blood supply area depends on vascular anastomosis can be 16*7cm ; The stem of flap is located anodic and it has higher survival rate. We can use it that design anotic stem flap to repair suprapubic and amphi tissue defection. Perforator flaps with pedicle in the middle containing perforating branches from the anterior cutaneous branch of the obturator artery are not aesthetically appealing, and are also limited by the ramus inferior ossis pubis, the recipe deep of the flap stem should be keep 1.35～1.45cm and tissues below it can be repaired thin to 0.90～1.00cm, the blood supply area depends on vascular anastomosis can be 14*6cm. The stem of flap is located middle, yet clinical application is less.Perforator flaps with inferior pedicle that contains lateral branches of the posterior scrotal (labial) artery are easy to transfer, and could be used widely. The recipe deep of the flap stem should be keep 1.25～1.35cm and tissues below it can be repaired thin to 0.90～1.00cm, the blood supply area depends on vascular anastomosis can be 18*7cm . The stem of flap is located inferior , and clinical application is widespread, such as penis and scrotum reconstruction, vagina reconstruction, hypospadias reparation.2005～2009, we apply with perineal perforating flap 28 cases. 16 male, 12 female. The inguinal and/or perineal perforating branches of the superficial external pudendal artery is used as blood vessel stem 7 cases. Perforator flaps with pedicle in the middle containing perforating branches from the anterior cutaneous branch of the obturator artery is used as blood vessel stem 1 cases. Inferior pedicle that contains lateral branches of the posterior scrotal (labial) artery is used as blood vessel stem 20 cases. The largest area of flap is 17*8cm, the smallest area of flap is 10*5cm,all patients'wounds are primary healing. With 6～12 months follow up, the perineal regions of patients are not obviously alter. Some patients who have their penis or vagina reconstructed are satisfied with sex life.[Conclusion] The perineum has abundant blood supply, venous return, and innervation. Due to its covert location and manoeuvrability, perforator flaps from this region are good sources of donor tissue for perineal reconstruction.The perforator flap has not only thin like other flap but also solve questions of limited area and difficult revolve. The operation is safe, easy to grasp, high achievement ratio. The perinel perforator flap is good at repairing the defection of tissue. All patients feel good after operation. It is a good way to extend.