Anatomic Study Of TheVsscular Sturucture Of The Cutaneous Branch-chain And The Cutaneous Branche-chain Flap Based On The Cutaneous Perforators Of The Posterolateral Lower Leg

ObjectiveThe development of flap went through axial-pattern flap, then perforators flap. Lots of researches about flap show that, when perforating branches of the original artery reach the skin, the perforating branches will give off branches to connect perforating branches nearby, in this way, a cutaneous vascular chain whose long axis is coherent with the original arterys will be formed, this case is evident especially on the end of limbs. We combine this cutaneous vascular chain and perforator of proximal or distal to harvest the flap, then we get cutaneous branch-chain flap. Cutaneous branch-chain flap can be designed into pedicle transposition flap and free flap. The idea of cutaneous branch-chain flap is another beginning in flap researches, while applying it to clinic still stays on the primary stage. Clinical application mostly chooses to reversal base the perforator, flaps are mainly minitype ones, it’s used to repair damaged fingers and toes, the survival is better and the damage is less, this is a desirable way to repair small tissue defect. But the size of the flap we can get is still restricted to the area around the vascular chain. Our research is concerned with the establishment of cutaneous branch-chain flap vascular system, the exsitence of lower leg posterolateral cutaneous branch chain which is constant and thorough, and the area where the lower leg posterolateral cutaneous branch chain stays. In this way, we provide the anatomical basis for clinical application of lower leg posterolateral cutaneous branch-chain flap.MethodsWe observe the establishment of cutaneous branch chain and the connecting type of lower leg posterolateral cutaneous branch chains between each other, via microscopic anatomy, gross anatomy, computed tomography scan, corrosion casts and Skin transparent. Then we confirm the area where lower leg posterolateral cutaneous branch chains stay. We get 25 fresh lower limb specimens whose sacroiliac joint are broken and skin without injury and operation. The other 21 specimens are perfused with red latex through arteria femoralis, we remove superficial fascia in adipose tissue by retrograde dissection and anterograde dissection under microscope, in order to show the chain match between perforating branches and those their branches fully, and observe the form of perforating branches and cutaneous branch chains. We try to show the linking vessel between perforating branches, and do the track dissection on every vascular branches. The vascular casts which are made of 2 legs specimens are used to observe the vascular construct subtle structure of cutaneous branch chains, in order to make up for the shortage of microscopic anatomy of exposed imperceptible vascular.2 leg specimens are perfused with red latex, after that, we do the CT scan first to observe the distribution of perforating branches and vascular chains, then do the careful dissection under microscope. After that, we cut lower leg skin to do skin transparent, then observe the distribution of vascular chains and the connection type between perforating branches. Divide 23 lower leg specimens into 7 average range from the highest point of fibular head to edge of external ankle, then measure the length of the fibula, peroneal artery diameter and the length of perforating branch pedicle. The area where arteria peroneal perforating branches distribute.the perforators Located in interval due to the next interval. Considerating clinical practicability and the possible error in measuration, we include the perforating branches whose diameter >0.5mm into our statistical analysis.ResultsNo.l The Establishment Of Cutaneous Branch-chain Flap Vascular System1. Dissect and observe cutaneous branch chains under microscope:①Vascular chains on fascia:When perforating branches go through deep fascia, they will come into two vascular chains, they are vascular chains under deep fascia and vascular chains on fascia. Vascular chains on fascia are cutaneous branch chains here. When perforating branches go through deep fascia and in the superficial fascia, they give off branches to connect with perforating branches nearby to form the direct linking vessel. Compared with vascular chains under deep fascia, vascular chains on deep fascia are plentiful, and the diameter of direct linking vessel is larger, the range between (0.5～1.0) mm to mm, while the diameter of communicating branch like this usually< 0.5mm where more perforating branches distribute. Generally, perforating branches can be divided into lengthways and crosswise vascular chains, lengthways vascular chains go into the same direction as axis of limbs and the original vascular which give off perforating branches. Crosswise vascular chains go into the direction that is vertical with the axis of limbs.② Distribution regularities of vascular chains:The lengthways cutaneous branch vascular chains of lower legs distribute in a similar way, that is to say, we will see an obvious cutaneous branch vascular chains along cutaneous nerves. The cutaneous branch vascular chains along cutaneous nerve are thick, the direct linking vessel between perforating branches repeat to give off branches to match each other which come to level 2 to 4.2.Specimens observation by CT scan and corrosion casts:Crowed direct linking vessel between perforating branches are complicated and connected with each other like hairs. And the closer to skin, the thiner the vascular is, and the vascular chains are more, which come into subdermal vascular network. The subdermal vascular network is located outermost layer of perforating branches and the direct linking vessel between perforating branches. Besides direct linking vessel between perforating branches, dermal vascular network is another connection format between perforating branches.3.Vascular chains observationg of Skin transparentspecimens:Skin transparent specimens show that, in superficial fascia, the osculations of perforating branches are rich, they form axial and lateral perforating branches, which makes the cutaneous branches osculations of the whole lower leg skin look like a spider web. Because of that, the lower legs skin blood suppply of posterolateral area, lateral area, proparea, anteromedial area and posterior inner-area are connected, instead of independent, the blood supply can goes in both the longitudinal and transverse direction.4.Observation of the establishment of cutaneous branch vascular chains:By observing vascular chains on deep fascia and subdermal vascular chains, the establishment of cutaneous branch vascular chains consists of 4 parts, perforating branches, direct linking vessel, indirect linking vessel, connunicating branch. The direct linking vessel is the vascular in adipose layer which connect with perforating branches. Indirect linking vessel is the Small vascular anastomosis in or under corium layer. Connunicating branch is the vascular which connect the direct linking to the indirect linking,.No.2 The Anatomy of Lower Leg Posterolateral Cutaneous Branch-chain Flap1. Measuurement results of perforator of the peroneal:In 23 specimens,127 perforating branches come from arteria peronea, there are 3-9 branches on every sides, 4.16±1.86 branches on average, the average diameter of perforating branches in deep fascia is (0.92±0.25,0.56～1.19) mm. ① As for arteria peronea perforating branches, perforating branches mostly concentrate in region 3,4,5 and 6, and the number of perforating branches is 23,35,27 and 32, and the respective percentage of all the perforating branches is 11.81%,27.56%,21.26% and 25.20%. The place where arteria peronea perforating branches go out of deep fascia mostly concentrate in area below fibular head about 10-30 cm.23 leg specimens give off perforating branches in region 6, then most in region 4.② About the length and external diameter of arteria peronea perforating branch pedicle, we can see that, external diameter of arteria peronea perforating has no significant different in all of regions (p>0.05), perforating branch pedicle in region 1,6 and 7 is short, the length is 3.79、(3.95±0.56,2.78～5.12)cm and (3.21±0.78,2.38～3.53)cm respectively; the lengthes of perforating branch pedicle in region 2,3,4 and 5 is not signifcant different (p > 0.05), and is (5.47±1.79,4.18-7.89)cm、(5.78±1.02,3.98～7.12)cm、(6.87±0.89,5.26～6.13)cm and (5.23±1.68,3.68～5.14)cm. There is a significant difference between 2-5 regions and 6 or 7 region in the lengthes of perforating branch pedicle (p<0.05). ③ Concerning the course of arteria peronea perforating branches, perforating branches of Nearly period of peroneal artery mostly go through soleus, the route is long and the longest can be 5.12cm, average (3.35±0.66)cm. The perforating branches which go through flexor hallucis longus are in region 4 and 5, the initial part go in the muscle, and the length is (1.65±0.47)cm, ultimately go out through posterior-lateral intermuscular space. The majority of arteria peronea perforating branches in region 6 go through intermuscular space.2. Distribution of cutaneous branch chains:The fibula length of 23 specimens is (34.78±17.78)cm, the number of posterior-lateral lower leg cutaneous chain branches is 115, every side has (3.31±1.65) branches, the diameter is (0.99±0.23)mm, perforating branches nearby form cutaneous chains. We measure the distance between the first and last perforating branches from deep fascia to fibuar head, and calculate the percentage of fibular length. The distribution of cutaneous is in lower leg lateral midway down (28.33±15.69%)～(87.04±17.38%). Except the perforating branches in first region, all perforating branches in other regions participate in forming cutaneous branch chains, mainly in region 3,4,5 and 6, and all the perforating branches in region 3 and 6 take part in that, percentage is 100%. As for the number of cutaneous branch chain specimens in every region, it’s concentrate in region 3,4,5 and 6, and 23 specimens in region 6 participate in forming cutaneous branch chains, the percentage is 100%.3. The morphopothological observation of arteria peronea perforating branch cutaneous branch chains:① Endoscopic anatomy:Arteria peronea perforating branch cutaneous branch chains have close anastomosis with perforating branches from anterior tibial artery, this direct linking vessel have 3 forms:the first is the one which goes along lateral sural cutaneous nerve, and this one is big in diameter(0.5-1.0)mm, mainly in region 3,4 and 5, whose diameter is stable; the second one without big diameter has cutaneous nerves go through perforating branches, but by several thiner direct linking vessels, mainly in region 6 and 7 of lateral lower calf; the last form is direct linking vessel doesn’t go along with lateral sural cutaneous nerve, and the diameter of this one is smaller(0.2-0.3)mm. ② Observation of skin transparent method: Arteria peronea perforating branches nearby have anastomosis with direct linking vessel, which form vertical and lateral cutaneous branch chains, and vertical ones are more obvious, most of them concentrate in region 3-6. The direct linking vessel is distinct, and form obvious continuous blood supply. ③ CT scan and vascular casts observation of arteria peronea cutaneous branch chains:By MIP image observation of arteria peronea perforating branches distriction, the origins of perforating branches in peroneal artery of lateral calf concentrate in region 3-6(10-30)cm, where we can see the constant perforating branches from lower peroneal artery in region 6. VR color image displays calf lower perforating branches, direct linking vessel and vascular chains. Direct linking vessel and indirect linking vessel among perforating branches are complicated and connected like hair, they form the vertical cutaneous branch chains. And the closer to skin, the thiner the vasculars are and the high density shadow is more concentrated. ④ Vascular casts observation of arteria peronea cutaneous branch chains: direct linking vessel among perforating branches are complicated and connected, perforating branches mainly in region 3-6.Conclusion1. The establishment of cutaneous branch chains are composed by perforating vascular, direct linking vessel、indirect linking vessel and connunicating, cutaneous branch-chain flap is reliable on vascular anatomy construction and blood flow dynamics.2. Reversed or free cutaneous branch-chain flap pedicle perforator, the blood supply of flap comes from cutaneous branch chains, and the perforating branches which can’t form pedicle but cutaneous branch chains are ligated, so the pedicle can prolong by direct linking vessel subtly.3. The long axis of flap should be as parallel with the original vasculars as possible, and the in the place where cutaneous nerves stay should be in the same direction as nerves. Apply the lateral cutaneous branch chains appropriately to increase the width of flap, then we can get a larger cutaneous branch chain flap.4. Among perforating branches in posterior-lateral calf, there are constant and perfect cutaneous branch chains, mainly distribute (region 3-6).5. There is a constant perforating branch from peroneal artery over lateral malleolus 5-10cm, and it can be used as the cutaneous branch chain flap vascular of anterograde transposition, to repair injuries of lower calfs and feet.6. Among perforating branches in posterior-lateral calf, there are constant and perfect cutaneous branch chains, and they connect with blood vessels of nutrition Sura lateral cutaneous nerve, so they are good choice for reversed cutaneous branch-chain flap of 1 posterior-lateral ower leg pedicle vessels...