The Anatomical Foundation And Clinical Study Of Sensory Reconstruction Of Anterolateral Thigh Flap In Repairing Widespread Soft Tissue Defects In Heel

The heel of human body plays an important role in weight loading, ambulation and absorption of vibration. Because of heel's special anatomic structure and physiological function, traumatic soft tissue defects in heel are often repaired by cutaneous flaps. In early days, the survival rates have been paid more attention in the studies of cutaneous flaps transplantation, and we always emphasis on the blood circulation of flaps. With the development of microsurgical technique, the problem of repairing the wound in heel was solved on the whole result from many kinds of island skin flaps with distally-based vessel pedicle and free skin flaps, myocutaneous flaps have been used in repairing clinical cases one by one and the survival rates of flaps have been increased step by step, but the heel repaired without sensory flaps gave rise to many problems, it is likely to be rough and weather-shack, can not resist wearing and withstanding pressure, the worst is it raise the possibility of being worn out, scalded, cold injuried and chronic ulceration, moreover, there is no sensory impulse introduced into the footplate, it can not build up concerted reaction with center, lead to unsteady walking under weight loading, the function of foot can not bring into full play. For this reason, in the case of repairing traumatic soft tissue defects of heel, more and more clinicians think highly of its sensation reconstruction as well as its blood supply, texture and thickness.Widespread soft tissue defect in heel is a severe injury, it's difficult to cure, lead to high disability frequency if couldn't received rational treatment. The fasiocutaneous flaps nearby are too small to meet requirements. The island flaps of calf with distally-based vessel pedicle can be used to repairing moderate area wounds in heel, but are limited to be used in repairing large area soft tissue defects in heel and the sensory restoration and stability of the flaps are not satisfied. Free flaps or myocutaneous flaps such as latissimus dorsi muscle-skin flap, thoracic umbilical flap and scapular flap can be used to repair all sorts of wounds in heel because of their large dermatomic area, but the greatest disadvantage is there is no specified cutaneous nerve to dominate the flap, sensation always is very poor, and it always appear to be very fat and clumsy, and the flap's doughy sensation lead to poor stability. The anterolateral thigh flap (ALTF) is considered as an ideal free flap for repairing large area soft tissue defects in heel at present, because it has so many advantages such as abundant blood supply, fitting thickness, wide flap territory, covert supply-area, especially of it's lateral femoral cutaneous nerve(LFCN) can be used for sensory reconstruction, and with femoral fascia together can keep the heel's stability. However, whether it's necessary to coapate cutaneous nerve for the sensory recovery is always in debate in home and abroad at present because the sensory recovery of ALTF don't meet the goal though we have coapated LFCN. So, it is necessary to approach the reasons for unsatisfactory sensory restoration of the ALTF even we have coapated its cutaneous nerve, and to improve the modus operandi so as to obtain better postoperative results. In abstract, after coapating the cutaneous nerves, the sensory restoration may come true if nerves can regenerate and pass through the stoma and grow along built-in tubes of endoneural membrane to arrive the neurocutaneou's ends. but there is no neurocutaneous morphology research aim directly at sensation reconstruction of skin flap. What on earth lead to poor sensory recovery of flap? And how to improve the flap's function? All these clinical problems are necessary to resolve as soon as possible.This anatomic research analyze the dissection of cutaneous nerves including the LFCN, the medial calcaneal nerve(MCN) and the lateral calcaneal nerve(LCN) that dominate the ALTF and heel from the view of sensory reconstruction of ALTFs transplanted for repairing widespread soft tissue defects in heel, to get the message of their number, distribution, variation, and the extemal diameters of different plane, observe the histology of the LFCN, the MCN and the LCN's slices of different planes, get the message of their characteristics of sectional morphous, regularity of nerve fiber bundles and the quantity of nerve fiber. To approach the morphologic facts that influence the sensory recovery of the ALTF, and based on the anatomic and histological characteristics of the LFCN, the MCN and the LCN's dissection and sectional morphology, to improve the method of the ALTF's design, choose suitable cutaneous nerve and rational anastomosis position according to the recipient site and its scope, select suitable suturation means according to the morphological characteristics of nerval section, combined with curative effect's analysis of clinical cases to try to fred a new method to rebuild the sensation of ALTF.ChapterⅠAn Anatomic Study of the LFCNObjective To guide sensory reconstruction of ALTF by approaching extemal diameters of the LFCN at different plane and its shape,distribution and variation in the area of anterolateral thigh.Methods Choose 12 adult cadaver specimens with 21 lower limbs, dissect LFCN to observe its distribution, course and variation. Measure the position where the bole of LFCN appear below the inguinal ligament(IL), the distance between the plane where the bole sent out the posterior branch and the anterior branch and the anterior superior iliac spine(ASIS), and the distance between the position where the LFCN appear from the IL and the ASIS, and the external diameter of the bole of LFCN on the planes of just below the IL and after the bole send out posterior branch and anterior branch.Results The LFCN passes through under the IL and descends along a line between the ASIS and the lateral border of the patella and sents out the posterior branch 0～16.9 cm (4.8cm on average) below the ASIS and the anterior branch 6.7～24.1cm (14.2cm on average) below the ASIS. The medial and anterior segments descended subcutaneously to the knee. The LFCN was divided into six patterns on the ground of their branches: typeⅠ: common with three branches (9/21), typeⅡ: posterior branches at high position (5/21 ), typeⅢ: posterior branches absent (3/21), typeⅣ: anterior branches absent (1/21), typeⅤ: the diameter of the LFCN is thinner than 1.5mm (2/21), typeⅥ: the LFCN absent (1/21).In one case of posterior branches absent type, the cutaneous sensation of the superior segment of lateral femoral field is dominated by the perforating branches sent out from the superior part of femoral nerve,while in 2 typeⅤcases and 1 type of the LFCN absent, the cutaneous sensation of the midst and inferior segment of lateral femoral field is dominated by the gross perforating branches sent out from the superior part of femoral nerve. The shape of the majority of LFCNs and its anterior and posterior branches are oblate,The diameter of the bole of LFCN at the position where it appears from below the IL is 1.18～4.52mm (2.68mm on average), its diameter after send out the posterior branch is 0.80～4.10mm (2.18mm on average) and after send out the anterior branch it turns to be 0.44～2.60mm (1.63mm on average)Conclusion The LFCN is an ideal cutaneous nerve to rebuild the ALTF's sensory function because its anatomical position is relatively constant, its external diameter is big and the diameter of the bole of LFCN at the position where it appears from below the IL to the position where the anterior branch appears is so gross that it's anatomic characteristic is very suitable for nerves suturing. ChapterⅡAn Anatomic Study of the MCNObjective To approach the origin, position where it is sending out, course and distribution of the MCN and the external diameter of its bole and branches, investigate the possibility of using the MCN for rebuilding sensation as the recipient site's cutaneous nerve in heel.Methods Choose 20 adult cadavers' lower limbs, dissect the MCNs and their branches, observe their shapes, courses and their distribution, measure the position where it is sending out, the perpendicular distance from the branching location to the tip of medial malleolus and the external diameters of its bole and branches.Results The frequency of the MCN is 95% (19/20) in this array. Among of them, all the MCN arise from the tibial nerve at 3.3 cm (0～12cm) up the horizontal plane of the tip of medial malleolus, three MCNs go along on the surface of malleolus canal after sending out from the tibial nerves, they send out anterior branches and posterior branches from 2.9cm above the horizontal plane of the tip of medial malleolus to 2.3cm below the horizontal plane(0.3cm below the horizontal plane on average). The anterior branch dominates the cutaneous sensation of the anterior part of the medial calcaneal and calcar pedis' weight loading field, while the posterior branch dominates the cutaneous sensation of the post median part. The shapes of the majority of MCNs and their anterior branches and posterior branches are like circular cylinder, the external diameter of the MCN's initiation is 0.78～2.70mm (1.58mm on average), that of the anterior branch's initiation is 0.50～2.00mm (1.13 mm on average ), that of the posterior branch's initiation is 0.30～1.88mm (0.90 mm on average)Conclusion The MCN is an ideal cutaneous nerve for sensory reconstruction in heel, especially in its weight loading area because its anatomical position is relatively constant, and its external diameter and section area are suitable, besides these, the initiation of it is not close to the heels' weight loading area.ChapterⅢAn Anatomic Study of the LCNObjective To approach the origin, position where it is sending out, course and distribution of the LCN and the external diameters of its trunk and branches, and investigate the possibility of using the LCN for rebuilding sensation as the recipient site's cutaneous nerve in the lateral calcaneal area.Methods Choose 20 adult cadavers' lower limbs, dissect them and reveal the position where the medial sural cutaneous nerve and the lateral sural cutaneous nerve converge and the tip of lateral malleolus, observe the origin, position where it is sending out, course and distribution of the LCN and the external diameters of its bole and branches, set the horizon through the tip of lateral malleolus as the location sign, measure and record the perpendicular distance from the planes where each LCN to the tip of lateral malleolus'transverse plane and every LCN's external diameters.Results Majority of medial sural cutaneous nerves and lateral sural cutaneous nerves converge 8.9cm average (2.4～21cm) above the plane of the tip of lateral malleolus to be sural nerve, then it sends out 1～3 LCNs from its lateral part, the first lateral calcaneal nerve(LCN1) sent out from sural nerve or lateral sural cutaneous nerve from the plane of the tip of lateral malleolus to 7.2cm above, the second lateral calcaneal nerve(LCN 2) sent out from sural nerve from 2.5cm above the plane of tip of lateral malleolus to 1.7cm below, the third lateral calcaneal nerve(LCN3) sent out from sural nerve from the plane of the tip of lateral malleolus to 1.8cm below, the shapes of them are almost like circular cylinder. All LCN proceed downward vertical from the trunk of sural nerve, the endings are distributed in the lateral calcaneal area.When near the lateral calcaneal, the LCN1 sents out 2～4 branches to dominate cutaneous sensation of the lateral calcaneal area, the ending is distributed over the lateral part of the lateral calcaneal's weight loading field. The shape of them are almost circular cylinder.The external diameter of the three branches is 1.62mm, 1.10mm and 0.85mm respectively, and the external diameter of the LCN1 in the three types is 1.53mm, 1.72mm and 1.59mm respectively.Conclusion The LCN1 is an ideal cutaneous nerve for sensory reconstruction in heel, especially in its lateral calcaneal area because its anatomical position is fairly constant, its external diameter is gross, and the initiation is not close to the lateral calcaneal area.ChapterⅣThe Histomorphological Study of the LFCN, the MCN and the LCN:Observation of Sectional Morphous and Measurement of Nerve Fibre NumberObjective Observe the sectional morphous of the LFCN, the MCN and the LCN, the quantity and distribution of their nerve fiber bundles, quantity and density of their nerve fibers. To provide the anatomic proof for selecting suitable cutaneous nerves, anastomotic position and means of suture to reconstruct the sensation of the ALTF used to repair extensive soft tissue defects in heel.Methods Choose 7 adult male corpses, take the nerval samples respectively from the LFCN 5cm below the ASIS and the initial segment of the MCN and the LCN1, fixed, dewatered gradiently, embedded, located, and made them into semithin sections, dyed with toluidine blue. Observe the nerves's sectional morphous, the quantity and distribution of their nerve fiber bundles under 40 times amplified, count the quantity of nerve fibers and determine the density of them by amplified 100 times, 200 times and 400 times. The pictures were taken by a medicine figure imaging analysis system named MOTICMED 6.0. Use photoshop 7.0 version precinct software for measuring and calculating the area of the nerve fiber bundles and the photoshop grid function was used to measure the density of the nerve fibers. Data analysis was performed by using Kruskal-Wallis H test, of which several specimens designed completely random. A P value of <0.05 was considered statistically significant.Results In our cross-section study, among of 7 LFCN samples, 5 were oblate, 2 were ellipse, the majority of nerve bunches lined up transversally and had imcompatible diameters, in addition, there were much adipose tissue lying in and out the nerve fiber bunches. On the contrary, among of 7 MCN samples, only one was oblate, 6 were ellipse, the majority of nerve bunches had similar diameter and disposed concentratedly, there were little adipose tissue while abundant nerve fiber tissue in the trunk of MCN. The majority of LCN (6/7) were ellipse, the majority of nerve bunches (5/7)had imcompatible diameters and disposed with triangle or polygon in those specimens with over two nerve bunches, nerve bunches located at one side of the bole and there were much adipose tissue lying out the nerve fiber bunches in two samples. As to LFCN, MCN and LCN1, the median number of nerve bunches was 4, 3 and 4, respectively. The median number of nerve fibers' area was 114.8 um~2, 126.92um~2 and 102.76 um~2, respectively. The median number of nerve fibers' density was 11.43/ um~2, 6.47/ um~2 and 10.08/ um~2, respectively. The median number of nerve fibers was 987, 862 and 570, respectively.In the arrays, the difference of number, density and area of these nerve fibers in this three cutaneous nerves was considered statistically insignificant.Conclusion The MCN and the LCN1 are ideal cutaneous nerves to suture with LFCN in the ALTF used to repair widespread soft tissue defects in heel because they have similar histomorphological characteristics with the LFCN.ChapterⅤInnervation of Free ALTFs for RepairingWidespreadly Traumatic Soft Tissue Defects in HeelObjective To explore a new method of innervating ALTFs for repairing widespreadly traumatic soft tissue defects in heel and analyze its initial results of clinical application.Methods The clinical cases were divided into 2 groups. In control group, eight consecutive ALTFs were transplanted in 8 patients for repairing widespreadly traumatic soft tissue defects in heel from October 2004 to September 2005 in our department, the sensory reconstruction of ALTFs based on traditional method: selecting sural nerve, saphenous nerve or tibial nerve as innervate nerve in the recipient site and simple suturing their nerve membrane in end to end or end to side. In research group, six consecutive ALTFs were transplanted in 6 patients for repairing widespreadly traumatic soft tissue defects in heel from October 2005 to September 2006, the sensory reconstruction of ALTFs included such as design and section of the LFCN, select the cutaneous nerves in recipient sites and anastomotic position as well as suture means based on the research of the anatomic and histomorphological characteristics of LFCN, MCN and LCN. The patients were evaluated at 3, 6, 9 and 12 months on the postoperative follow-up parameters including flap contour, flap stability, locomotor activity, touch sensation, pain sensation, static two-point discrimination, and thermal sensibility. Results All the free flaps survived in both groups. The flaps have good blood supply, no vassular articulo and infection, all the wounds are primary intention healing. All the 8 cases in the control group follow up 6～18 months (9 months on average), 5 have good shape, 3 are fat and clumsy, the rate of good sensory recovery is 25%, one of which have been burned 2 times owing to poor sensory recovery, another 2 had light ulceration. All the 6 cases in the research group follow up 3～12 months (6 months on average), 5 have good shape, 1 was fat and clumsy, the rate of good sensory recovery is 66.7%, no ulceration happened.Conclusion When repairing widespread sofl tissue defects in heel, satisfactory sensory function restoration can be obtained by paying attention to the distribution and variety of ALTFs, selecting suitable cutaneous nerves and rational coaptated position as well as suitable suturation means which based on the anatomic and histomorphological characteristics of the LFCN, the MCN and the LCN.