Moroe Beppu, Douglas R Hanel, Geoffrey H.E Johnston, Jose M. Carmo, and Tsu-Min Tsai

THE OSTEOCUTANEOUS FIBULA FLAP: AN ANATOMIC STUDY Recent studies related to the fibula flap have disagreed regarding the anatomy of the cutaneous branches of the peroneal artery. To clarify this issue, various dissections of 35 injected fresh cadaver legs were done. Identifiable skin branches were found in 23 of 25 dissections. Skin branches from the proximal third of the peroneal artery always travelled an intramuscular course. Skin branches from the distal twothirds of the peroneal artery were usually affixed to the posterior crural septum. Legs with peroneal artery skin branches had from three to seven branches (average: 4.7); each branch contributed to the fibular periosteal blood supply The most reliably found skin branch was located within 2 cm of the fibula midpoint. These findings reinforce the fact that a large skin island supplied by branches of the peroneal artery can be harvested with the fibula flap, and that the most reliable cutaneous vessels are found in the lower twothirds of the leg, run posterior to the fibula in the posterior crural septum, and are always associated with muscular side branches.

In 1905, Huntington used a segment of fibula suspended on its vascular pedicle to bridge a large defect in the ipsi lateral tibia.1 It was not until the 1970's and the development of dependable microvascular techniques, that vascularized osseous grafts (flaps) could be used in the treatment of distant bony defects.2 Currently, vascularized bone flaps are indicated for large defects secondary to trauma, tumor resection, the treatment of osteomyelitis after sequestrectomy, and congenital pseudarthrosis.2"9 Because of the difficulty in monitoring vessel patency following these procedures, the concept of the osteocutaneous flap was introduced. It was based on the premise that an island of skin supplied by the same vessels as the bone would reflect thevascularity of the osseous segment.489 In addition, the cutaneous segment assisted in providing tension-free skin closure and reconstruction of soft-tissue defects.9 10 Anatomic studies and clinical examples have been reported for the iliac crest,11 distal radius,12 second metatarsal,13 and fibula.4?-9 Except for the fibula, the cutaneous markers for osteocutaneous flaps arose from previously described and clinically tested free-tissue transfer territories. Chen and Yan4 and Weiland et al.6 alluded to fibular cutaneous territories, but only when Yoshimura and

colleagues9 described 1 cm x 3 cm "skin buoys," were cutaneous markers for the fibula documented. They described three to four potential skin islands and three patterns by which the peroneal skin branches reached their destinations. Type A branches of the peroneal artery passed intramuscularly within the peroneus longus or soleus muscles, giving off muscular branches before entering the skin. Type B branches passed between the soleus and peroneal muscles within the intermuscular septum and gave off muscular branches before entering the skin. Type C branches passed directly to the skin along the same route as Type B branches, but without muscular side branches. Yoshimura and colleagues9 proposed that any of these three types of branches would adequately reflect the osseous blood supply of the transferred bone, and they gave clinical examples of Types B and C. In a later publication,14 this same group described larger areas of skin supplied by the peroneal artery for reconstruction of soft-tissue defects. Only two categories of cutaneous vessels were described: 1) musculocutaneous vessels passing within the substance of the peroneus and soleus muscles in the upper and middle third of the leg; and 2) cutaneous vessels that entered the skin in the middle and distal third of the leg. No mention was made of the peroneal artery branches that gave off

From the Christine M. Kleinert Institute for Hand and Micro Surgery, Louisville, Kentucky Reprint requests-. Dr. Tsai, One Medical Center Plaza, Suite 800, 225 Abraham Flexner Way, Louisville, KY 40202 Accepted for publication lanuary2, 1992 Copyright© 1992 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.

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ABSTRACT

muscular side branches to enter the skin between the peroneus and soleus muscles (their previously described Type B branches). Wei et a!.10 incorporated the concept of the osseous skin marker with the larger skin territory, coined the term "osteoseptocutaneous flap" for the fibula, and described the course of the peroneal artery skin branches. They found two distinct types of vessels. The first, the septal vessels, were found in the distal leg, had no muscular side branches, and were easily dissected. Although they were usually three to four in number, no septal vessels were seen in some of the legs. The second type, the musculocutaneous vessels, were consistently found in the proximal half of the leg. Although difficult to dissect, these musculocutaneous branches could stil l serve as osseous markers, when no septal vessels were found. The relationship between septal vessels and the cutaneous blood supply to the leg was further reinforced by the work of Carriquiry, Costa and Vasconez.15 These authors demonstrated that vessels that ran within the posterior crural septum of the leg always gave off muscular side branches before or upon entering the septum, reminiscent of the course of Type B vessels of Yoshimura. 9 In addition to defining the course of these vessels, they emphasized that the septocutaneous vessels, and not the muscular perforating vessels, supplied the muscle-investing fascia responsible for the perfusion of fasciocutaneous flaps in this region. The importance of these findings is that, if one proposes to transfer an osteocutaneous fibula flap, the best-perfused cutaneous segment will be one supplied by a septofasciocutaneous vessel. In order to consolidate these contributions to the anatomic description of this region, the following cadaver study was undertaken. The goals of this study were: 1) to outline the cutaneous territory of the peroneal artery; 2) to identify the types and locations of the vessels supplying this cutaneous territory; and 3) to define the relationship between the fibula, the peroneal artery, and this cutaneous territory. By accomplishing these goals, the most predictable and easily dissected osteocutaneous fibula flap could be developed.

METHODS AND MATERIALS

216

cadaver legs were then refrigerated at 3° C for 24 hr and dissected. The course of the peroneal artery was mapped from proximal to distal, with particular attention paid to recording the distance from the fibular long axis to the sites where cutaneous vessels entered the muscleinvesting fascia. Musculocutaneous vessels (Fig. 1A), found predominantly in the proximal half of the leg, were noted as far as 4 cm from the fibula in the posterior compartment of the leg. No musculocutaneous vessels were found in the lateral or anterior leg compartments. Septocutaneous vessels (Fig. IB, C) passed within 1 cm or less along the posterior aspect of the fibula and arborized into the muscle-investing fascia of the posterior and lateral leg compartments. On the basis of this information regarding the extent of perfusion, the potential territory of the peroneal artery was isolated prior to injection of ten more cadaver legs, by longitudinally incising the skin imme-

TypeA

n

4 n

Type C

n

Figure 1. A, Type A vessel. Musculocutaneous perforator passes through the muscle-investing fascia and arborizes This two-part study used 35 fresh cadavers, dis- in the subcutis. Type A vessels were found at the level of the sected within 36 hr of acquisition. The first part of the second quarter of the fibula (see Table 5). Br Type B vessel. Septocutaneous perforator gives off muscular side branches study was designed to demonstrate the skin territory before arborizing within the muscle-investing fascia. Branches supplied by the peroneal artery. The second part was travel in a predominantly transverse direction within the intended to define the peroneal artery's relationship fascia. Type B vessels were found in the distal two-thirds of to the fibula, the surrounding muscle, and the over- the fibula (see Table 5). C, Type C vessel. Septocutaneous perforator does not give off muscular side branches prior to lying fasciocutaneous segment. arborizing within the muscle-investing fascia. Branches PART 1. The popliteal artery in five cadaver right travel in a predominantly longitudinal direction within the legs was injected, each in the same way, by means of a fascia. Type C vessels were found in the distal third of the hand-held syringe with 60 cc of latex over 1 min. The fibula (see Table 5).

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OSTEOCUTANEOUS FIBULA FLAP/BEPPU, HAN EL, JOHNSTON, ET AL.

Ant. cural septum

Lat. compartment Post, cural -septum Deep post, compartment Sup. post, compartment 0 1990 Louisville Hand Surgery

Figure 2. This cross section of the leg at the mid calf demonstrates the plane and extent of dissection for injection studies done to identify the amount of staining in the territory of the peroneal artery. Starting at the border of the tibia, anterior and posterior fasciocutaneous flaps were elevated. The anterior flap stopped with the incision of the anterior crural intermuscular septum. The posterior flap stopped about 3 to 4 cm from the posterior crural intermuscular septum.

Figure 3. Staining along the lateral aspect of a dissected specimen.

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Ant. compartment

diately bordering the tibia and raising anterior and posterior fasciocutaneous flaps comprised of skin, subcutaneous fat, and muscle-investing fascia (Fig. 2). The anterior flap dissection ended with the incision of the anterior crural intermuscular septum. The posterior dissection stopped 3 to 4 cm from the fibula, with the intention of preserving the previously identified musculocutaneous vessels. These flaps were returned and sutured to their original position. An elastic tourniquet was placed 2 cm above the medial malleolus in order to eliminate collateral arterial communications about the ankle joint. The peroneal artery was isolated at its origin from the popliteal artery and injected with either 30 cc of latex (in eight specimens) or India ink (in two specimens). The area of skin staining was recorded (Fig. 3), and the limb refrigerated. Twenty-four hours later, the fasciocutaneous flaps were elevated, and the leg inspected. Latex- or India ink-filled vessels were identified, and their origin confirmed by following their course from the skin to the peroneal artery. If the tourniquet failed to prevent perfusion of a collateral vessel originating from a vessel other than the peroneal artery, the specimen was excluded from this part of the study. PART 2. Having identified the potential cutaneous territory of the peroneal artery, our attention was directed toward identification of the vessels originating from the peroneal artery and contributing to this territory. Therefore, the popliteal arteries of 20 additional cadaver legs were injected with latex. Injection was stopped with the appearance of injected material in the subcutaneous tissue. Volumes of injected material ranged from 40 to 60 cc. After refrigeration for 24 hr, the peroneal arteries were explored. Information as to

217

MAY 1992

Popliteal artery branches. The popliteal artery was the peroneal artery's relationship to the fibula, the popliteal artery, and the skin branches of the peroneal followed distally, using the tip of the fibular head for artery was recorded. Three legs from Part 1 of the study reference (Table 2, Fig. 4). Two to seven centimeters (average: 4.6 cm) distal to the tip of the fibular head, were similarly explored. the anterior tibial artery branched off the popliteal artery, piercing the anterior interosseous membrane RESULTS just distal to the inferior margin of the popliteus muscle. The blood supply to the fibular head and the proximal epiphysis was found in this area. It arose from PART 1: SKIN TERRITORY. Skin staining averaged 9.9 cm in width (range: 8 to 11.5 cm) and 21.4 cm in branches of the popliteal artery, prior to the origin of length (range: 20 to 24 cm) (Table 1, see Fig. 3). The area the peroneal artery. The posterior tibial artery ran for 1 to 6 cm (averof staining averaged 213 cm2 (range: 160 to 253 cm2) and was located on the distal two-thirds of the lateral age: 3.0 cm) before giving off its largest branch, the leg. Four borders outlined the area: superior, inferior, peroneal artery. This arterial segment, spanning the posteromedial, and anterolateral. The superior border distance between the origins of the anterior tibial and was 4 to 6 cm distal to the tibial plateau. The inferior peroneal arteries, has been referred to by Henry16 as border corresponded to the ankle tourniquet and may the common tibial-peroneal trunk. have been artifactitious. The anterolateral margin exPeroneal artery and the origin of its cutaneous branches. tended just beyond the anterior intermuscular sep- From its origin, the peroneal artery travels laterally tum. The posteromedial border extended to an area between the tibialis posterior and the soleus muscles overlying the junction of the medial gastrocnemius (Table 3, see Fig. 4). Upon reaching the medial crest of with triceps surae. On the undersurface of the fascio- the fibular diaphysis, the peroneal artery descends cutaneous flap, injected material was seen in the fas- within a triangular fibro-osseous tunnel. This tunnel cial plexus, extending 2 to 3 cm beyond the margin of consists of a lateral wall (the fibular diaphysis), a floor skin staining. Although the inferior border of this area (the tibialis posterior muscle), and a sloped roof (the ofskin staining may have been artifactitious, we would soleus muscle proximally and the flexor hallucis musnot harvest fascia and cutaneous tissue distal to this cle distally). margin in clinical practice. Thus, the dimensions given The first peroneal skin branch arose 0 5 to 7.0 cm in Table 1 are of value from a clinical point of view. (average: 2.6 cm) distal to the origin of the peroneal The skin branches that were followed retrograde artery. This was 6.9 to 16 cm (average-. 10.2 cm) distal to to the peroneal artery travelled an intramuscular the tip of the fibular head. The last skin branch was course through the soleus and flexor hallucis muscles, encountered II 5to 25.7 cm (average: 18.2 cm) distal to or an intraseptal course through the posterior crural the origin of the peroneal artery. This corresponded to septum. The number of vessels eventually reaching the a point 17 to 32.5 cm (average: 25.8 cm) distal to the tip of the fibular head, and 5 to 14.5 cm (average: 9.9 cm) skin numbered from three to seven. proximal to the tip of the lateral malleolus. PART 2: VASCULAR RELATIONSHIPS. Information was Interposed between the most proximal and distal gained from the 23 dissections for the following: the relationship of the origin of the popliteal artery branches skin branches were one to five (average: 4.7) other to the fibular head; the peroneal artery and the origin cutaneous branches. They were separated from each of its cutaneous branches relative to the fibula itself; other by an average distance of 3.9 cm (range: 2 to 7.8 and the type and location of the peroneal artery's skin cm) (Table 4). In 21 of 23 specimens, a skin branch could be branches. found within 2 cm (average: 1.2 cm; range: 0.0 to 3.3 cm) of the midpoint between the tips of the head of the fibula and the lateral malleolus (see Fig. 4; Figs. 5, 6). Table I. Length, Width (cm), and Area (cm2) Each skin branch headed distally as it left the peroneal of Staining of the Skin Over the Fibula artery. The angle of descent, using a line perpendicular After Injection of the Peroneal Artery with Latex to the fibula for reference, increased from proximal to Specimen Width Area Length distal. This angle was 10 to 15 degrees in the proximal 24 100 240 1 vessels, and 45 to 65 degrees in the most distal vessels. 160 20 8.0 2 In the 11 specimens in which the first peroneal 3 10.0 210 21 artery skin branch arose more than 2 0 cm from the 4 231 22 10.5 origin of the peroneal artery, a large skin branch came 230 5 20 11.5 off the common tibial-peroneal trunk. In the other 12 253 6 11.0 ±'i 170 8.5 7 20 specimens the common tibial peroneal trunk did not 8.0-11.5 160-253 Range 20-24 give rise to cutaneous branches. Average

218

21.4

9.9

213

Types of peroneal artery skin branches.

Each peroneal

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OSTEOCUTANEOUS FIBULA FLAP/BEPPU, HANEL, JOHNSTON, ET A L

Flap

Fibular Length

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

38.0 32.0 34.0 34 5 37.0 35.0 34.0 36.5 36.8 38.0 36.0 33.0 40.0 34.0 34.5 37 0 37.0 33.0 33.0 37.5 37.0 35.0 39.5 32.0-40 0 35.8

IS

19 20 21 22 23 Range Average

Fibular Head to Anterior Tibial Artery

Length of Common Tibial-Peroneal Artery Trunk

Distance from Fibular Head to Division of Posterior Tibial-Peroneal Artery Trunk

4.0 7.0 5.0 2.3 3.0 2.0 4.5

2.5 3.0 3.0 2.2 3.0 5.0 2.5 3.5 2.0 3.6 3.0 1.0 1.5 2.5 3.5 4.0 6.0 2.0 25 4.0 3.0 3.5 1 3 1.0-6.0 3.0

6.5 10.0 8.0 4.5 6.0 7.0 7.0 6.0 8.0 10.0 6.0 5.0 6.0 9.5 9.0 8.5 11.0 7.5 6.2 9.5 7.5 8.0 6.8 4.5-11.0 7.5

2 5

cO

6.4 3.0 4.0 4.5 7.0 4.5

5.0 5.5 3.7 5.5 4.5 A 5 5.5 2.0-7.0 4.6

artery branch consisted of an artery with an external diameter between 0.5 and 1.5 mm, accompanied by oneortwo veins of slightly larger diameter. From their origin, they coursed next to the fibula and contributed to its periosteal blood supply. Three different types of skin branches were identified. Type A vessels entered the substance of a muscle and gave rise to multiple 25.9cm intramuscular branches before perforating the muscle(17.0-32.5) investing fascia and arborizing in the subcutis. Type B vessels passed within the posterior crural intermuscular septum, gave off muscular side branches, and entered the subcutaneous tissue where the posterior crural intermuscular septum joined the skin. Type C TP vessels were similar to Type B vessels in their course 35.8cm (32.0-40.0) but did not give off any muscular side branches. The leg was divided into thirds, using the fibula as reference (Table 5, see Fig. 1). In the proximal third of the leg, the skin on the lateral aspect was only partially vascularized by the peroneal artery, as demonstrated by the skin staining of Part 1 of the study. Dissection of the back of the knee revealed that the blood supply to Figure 4. The relationship between the fibular head, the popliteal artery (pop. a.), the origin of the tibialis anterior the skin overlying the fibular head came from branches artery (TA), the common tibial-peroneal trunk (CTPA), the of the inferior lateral geniculate, anterior tibial, or origin of the posterior tibial artery (TP) and peroneal artery popliteal arteries. In five specimens, no branches origi(PA), and the origin of the first and last skin branches (see nating in the proximal third of the leg from the peroTables 2 and 3). In 21 of 23 specimens a septocutaneous neal artery were seen to supply the skin. In these cases, perforator was identified within two centimeters of the midthe cutaneous blood supply was derived from the more point of the fibula (Table 4). This is the most reliable pedicle proximal vessels. In those cases where branches of the for the skin island.

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Table 2. Structural Relationships (cm) Between the Popliteal and Peroneal Arteries

l 4.6cm (2-7) 7.5crn i (4.5-11) 3.0cm I io.2cm (6.9-16) (1-6)

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JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 8, NUMBER 3

Structural Relationships (cm) of the Peroneal Artery and Its Branches

Origin of Peroneal Artery to First Branch

Flap

Fibular Head to First Branch

Origin of Peroneal Artery to Last Branch

Fibular Head to Last Branch

13.0 12.0

19.3 14.0 16.0 20.0 19.6 22.2 18.0 25.5 20.0 16.0 20.0 12.0 20.0 16.0 15 0 16.5 11.5 14.0 20.8 21.5 17.0 17.0 25.7

25.8 24 0

10.5 7.0 8.5

4 5

9.0 10.0

8.5 11.0 11.0 13.0 8.0 7.5 10.0 11 0 12.3 14.0

1.5 16 17 IS 19 20

9.0 6.9 16.0

21

8.5

n

9.0 7.8 6.9-16.0 10 2

23 Range Average

11.5-25.7 18.2

25 0 25.6 29 2 25.0 31.5 28.5

25.5 22.5 30.0

25.0 32.5 17.0-32.5 25.8

Table 4. Relationships Between Skin Branches of Peroneal Artery (Two Legs Had No Skin Branches)

Flap 1 2

i

4 5

I7 8 9 in 11 12

13 14 15 16 17 18 19 20 21

22 23 Range Average 220

Distance from Number Midpoint of of Skin Average Distance Fibula to Branches Between Branches Closest Branch* 4 6 5 5 5 6 4 7 4 6 4 3

4.0 3.14 4 1 3.4 42 4.0 5.0 3.88 5.83 2.7 4.3 3 75

4 -: 4

6 16

4 3 4 5 6 4 6 7 3-7 4.7

+0.6 + 2.0 + 0.5 -3.25 -0.7 + 1.5 +0.8 +0.15

7.75 2.0 4I

+ 1.18 + 1.5 +2.0 +0.5 + 2.0 +2.0 +3.0 0.0

2.7

+ 1.5

4.0 3.9 2.7 3.0 3.3 2.3 2.0-7.75 39

*Distal ( + ) or proximal (-) to midpoint.

0.0 +0.6 + 1.3

-1.0 + 1.2 + 1.1 0.0-3 25 1 2

Figure 5. The outline of the ideal osteocutaneous fibula flap. The axis of the skin island is just posterior to the fibula. The X marks the midpoint of the fibula.

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Table 3.

MAY 1 9 9 2

Figure 6. Cadaver specimen of the osteocutaneous fibula flap, showing a Type B vessel, most commonly located at the midpoint of the fibula and passing through the posterior crural intermuscular septum to vascularize the skin island.

peroneal artery were identified in the proximal third of the leg, each branch was Type A. They passed through the soleus or lateral gastrocnemius muscles, giving off numerous intramuscular branches. No cutaneous branches of the peroneal artery travelled through the peroneus muscles. In the middle third of the leg, Type A vessels were identified in eight specimens. In six of these limbs, they traversed the soleus muscle near the junction of the proximal and middle thirds. In the remaining two limbs, a vessel passed through the soleus muscle proximally, while another vessel passed through the flexor hallucislongus muscle near the midpoint of the fibula. Type B vessels were seen in every specimen in the middle third. They ranged from one to four in number. Although located throughout the entire middle third of the leg, they were most consistently found within 2 cm of the midpoint of the fibula (21 of 23 specimens). No Type C vessels were seen in the middle third of the leg. In the distal third of the leg, peroneal skin branches were noted in 19 of 23 specimens. Four limbs had two skin branches, one each of Type A and Type B. The remaining 15 legs demonstrated only a single branch, of which 11 were Type B, and four Type C. No skin branches arose from the peroneal artery in the lower half of the distal third. The most distal branch arborized in the fascial plexus posterior to the lateral malleolus.

DISCUSSION Table 5. Distribution of Types of Branches of the Peroneal Artery in Each Third of the Leg

Proximal Third

Middle Third

Distal Third

Flap

A

B

C

A

B

C

A

B

1

0

0

1

2

0

2

0

2

2 1 2 1 2

0 0

0 1 0

0

0 0

9

1

lu 11 12

18 19

1 0 1 1 1 3 0 0 1 2

2(1

(i

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2 1 3 2 3

0 0 0 0 0 0 0 0 0

0 0

0

2 3 4 5 6 7 8

0 0 0 0

13

14 15 16 17

1

1

1 23 3 Range 0-3 Average 1.2

0 0 0 0

0 0 0 0 0 0 0

a0 0 0 0 0 0

0

2 0 0 0 1 3 1 0

1

1 ! 3

0

2 3

0

[

i)

1 3

0 0 0 0

1 0 0 1 0-3 0.5

2

2 2 3 3 A 2 1-4

2 1

0

0 0 0 0 0 0 0 0 0 0 0 0 0 0

0

1 ;

0

0

0

]

0 0

0

0 0

0 0 0 0 0 0 0 (.! 0 0 0 0 0 0

]

1

0 1 1

0 0 1 0 1 1 1

1

1 1 0 1 1 0-1

0

0.7

c 1 !1 1 0

1 0 1 1

0 0 0 0

0 0 0 0 0 0 1

0 0 0 0-1 0.3

Vascularized fibula flaps are recognized as the microsurgical procedure of choice for large, long-bone defects.6-9 The versatility and reliability of this transfer is augmented by the concomitant transfer of skin supplied by the same vessel perfusing the bone, the peroneal artery.9 10The cadaver study presented here details the relationship between the peroneal artery and its combined osteocutaneous territory. Our recommendations regarding surgical technique are presented elsewhere.17 Most anatomic studies describe the origin of the peroneal artery relative to the popliteal vessel orto an arbitrary landmark such as the tibial plateau .1618 In this study, it was believed to be more appropriate to use the fibular head for reference. A common tibial-pero neal trunk, seen in 95 percent of angiographic and anatomic studies, was found in each specimen in this study. The common tibial-peroneal trunk originated 2 to 7 cm distal to the fibular head and travelled from 1 to 6 cm before dividing. The implication of these findings is that the pedicle to the vascularized fibula flap is short, especially if the proximal diaphysis is part of the transfer. The findings, that the peroneal artery arose from the common tibial-peroneal trunk an average of 7.5 cm 221

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222

distal to the fibular head, and gave off its first skin branch an average of 10.2 cm distal to the fibular head, reinforces the work of previous investigators. Restrepo, Katz, and Gilbert 19 demonstrated that the vascularity to the proximal fibular epiphysis and fibular head is not within the vascular territory of the peroneal artery. The same is true of the skin overlying the proximal leg. As seen in the first part of this study, there was no transport of latex or India ink to the region about the fibular head. In the second part of the study, musculocutaneous and septocutaneous vessels were identified in the proximal lateral leg, but they originated from the inferior lateral geniculate artery, anterior tibial artery, or the common tibial-peroneal trunk. These findings correlate well with the work of Carriquiry, Costa and Vasconez.15 The isolated peroneal artery injection studies demonstrated that the cutaneous territory of the peroneal artery starts at the proximal quarter of the leg and extends to the ankle joint. This territory is perfused by the three types of vessels similar to those described by Yoshimura9: musculocutaneous perforators (Type A); septal branches that give off muscular side branches (Type B); and septal branches that do not give off muscular side branches (Type C). The importance of these vessels relative to the perfusion of any cutaneous segments has recently generated considerable interest. Ponten 20 demonstrated that if muscle-invest ing fascia is included with the elevation of skin and subcutaneous fat, then cutaneous flaps could be elevated with lengths as great as three times the width. He attributed this enhanced blood supply to a previously neglected vascular network found in the muscle-investing fascia, and descriptively named these composites fasciocutaneous "superflaps."20 Further investigations have demonstrated the relative contribution of myocutaneous and septocutaneous perforators to these fasciocutaneous flaps.1521-23 It has been shown that musculocutaneous perforators pass perpendicular to the muscle, anastomose in the subcutis with other muscle perforators, and supply only a small area of skin. Musculocutaneous perforators contribute little to the blood supply of the muscleinvesting fascia. In contrast, septocutaneous vessels form a richly vascularized fascial plexus, from which a much larger area of skin is perfused. Those vessels destined to become septocutaneous branches frequently give off muscular side branches or provide osseous blood supply prior to entry into the septum. Once within the septum, these vessels may travel longitudinally or transversely, contributing to both deep and superficial fascial layers. These anatomic arrangements provide the basis for versatile flap design in longitudinal or transverse planes. Multiple small longitudinal vessels are taken to advantage in the creation of Ponten's superflapand Tolhurst's axillary flaps.2023 Single sizeable longitudi-

nal vessels account for the creation of free flaps such as the extension of the lateral arm flap over the proximal forearm or the saphenous artery flap. 2425 Transversely oriented branches allow the versatility of lateral design in such flaps as the radial artery, lateral arm, and the scapular-parascapular flaps.25-27 Germane to the osteocutaneous fibula flap is the finding that two to four septocutaneous vessels arise from the peroneal artery, course posteriorly to the fibula, and are easily identified in the distal two-thirds of the lateral leg. Type B cutaneous vessels (septocutaneous, with muscular side branches) were most frequently encountered. In addition to their contribution to muscle and skin, they were responsible for the blood supply to the periosteum of the fibula. At least one Type B branch was identified within 2 cm of the midpoint of the fibula in all but one specimen. Of interest, this is the same site for the most frequently identified nutrient artery in Restrepo, Katz and Gilbert's work.19 Each Type B vessel assumed a transverse orientation upon entering the muscle-investing fascia, and contributed to the capillary plexus proximally and distally. The less frequently seen Type C vessels (purely septocutaneous) were limited to the distal third of the leg. They travelled longitudinally and distally before arborizing about the ankle. From the work of Onishi, Murayama and Iwahira,22 it is inferred that these Type C vessels contribute little to the fascia proximal to their takeoff from the peroneal artery. To consider all septocutaneous perforators to be of one type is an oversimplification shared by Yoshimura in his work on the peroneal flap and by Wei et al. in their presentation of the osteoseptocutaneous flap.1014 Although the distinction between the septocutaneous vessels may be a moot point when considering the perfusion of a small skin marker, it is not moot when considering the axiality of vessels perfusing larger skin flaps.2122 The proximal extent of muscle-investing fascia perfused by septocutaneous vessels was similar to the findings of Carriquiry, Costa and Vasconez and corresponded to the most proximal area of skin staining.15 This is the same region where muscle-perforating vessels (Type A) were seen. The implication is that in this proximal region, the peroneal artery provides skin perfusion through the local effect of Type A vessels and from the muscle-investing fascia perfused by the more distally located Type B septocutaneous vessels. Clinically, this is important. Type B septocutaneous vessels contribute to the blood supply of the skin in the area perfused by Type A musculocutaneous vessels, but not vice versa, as implied by Wei etal.10 It is doubtful that the skin over the distal third of the leg can be perfused by musculocutaneous perforators found in the middle third of the leg. A cutaneous segment based solely on muscleperforating vessels will, by necessity, need to be much smaller than one based on septocutaneous vessels.

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JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 8, NUMBER 3 MAY 1992

OSTEOCUTANEOUS FIBULA FLAP/BEPPU, HANEL, JOHNSTON, ET AL.

Based on the dissection of 35 fresh cadaveric legs, we have detailed further the vascular anatomy of an osteocutaneous fibula flap, including 1) the cutaneous territory of the peroneal artery; 2) the course of the peroneal artery from the popliteal artery to the origin of the last fibular branch; 3) the number, course, and distribution of three types of peroneal artery branches; and 4) the presence of a reliable peroneal artery branch, upon which pedicle a fasciocutaneous extension of the fibula flap might be based.

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HuntingtonTW: Case of bone transference: Useof a segment of fibula to supply a defect in the tibia. Ann Surg 41:249, 1905 TaylorGI,MillerGDH, Ham FJ: The free vascular ized bone graft, a clinical extension of microvascular techniques. Plast Reconstr Surg 55:533, 1975 Allieu Y, Gomis R, Yoshimura M, et al: Congenital pseudarthrosis of the forearm—Two cases treated by free vascularized fibula graft. I Hand Surg 6:475, 1981 Chen Z-W, Yan W: The study and clinical application of the osteocutaneous flap of fibula. Microsurgery 4:11, 1983 Usui M, Ischii S, Yamamura M, et al: Microsurgical reconstructive surgery following wide resection of bone and soft tissue sarcomas in the upper extremity. I Reconstr Microsurg 2:77, 1986 Weiland AJ, Moore JR, Daniel RK: Vascularized bone autografts: Experience with 41 cases. Clin Orthop 174:87, 1983 Wood MB, Cooney WP: Vascularized bone segment transfer for management of chronic osteomyelitis. Orthop Clin North Am 15:461, 1984 Wood MB, Cooney WP, Irons GB: Lower extremity salvage and reconstruction by free tissue transfer. Clin Orthop 201 :151, 1985 Yoshimura M, Shimamura K, Iwai Y, et ah : Free vascularized fibular transplant. I Bone Joint Surg 65A:1295, 1983 Wei FC, Chen HC, Chuang CC, Noordhoff MS: Fibular osteoseptocutaneous flap: Anatomic study and clinical application. Plast Reconstr Surg 78:191, 1986

11. Taylor GI: The current status of free vascularized grafts. Clin Plast Surg 10:185, 1983 12. Beimer E, Stock W: Total thumb reconstruction: A one stage reconstruction using an osteocutaneous forearm flap. Br I Plast Surg 36:28, 1983 13. Rose EH: Reconstruction of central metacarpal ray defects of the hand with free vascularized double metatarsal and metatarsalphalangeal joint transfer. ) Hand Surg 9A:28, 1984 14. Yoshimura M, Imura S, Shimamura K, et al: Peroneal flap for reconstruction in the extremity: Preliminary report. Plast Reconstr Surg 74:402, 1984 15. Carriquiry C, Costa MA, Vasconez LO: An anatomic study of the septocutaneous vessels of the leg. Plast Reconstr Surg 76: 354, 1985 16. Henry AK: Extensile Exposure, 2nd ed. Baltimore: Williams and Wilkins, 1957, p 247 17. Tonkin MA, Hanel DP, Scheker LR: Vascularized fibular osteocutaneous graft: Surgical technique and clinical study. Aust NZ I Surg 60:51, 1990 18. Trotter M : Level of termination of the popliteal artery in the white and negro. Am 1 Phys Anthropol 27.109, 1940 19. Restrepo J, Katz D, Gilbert A: Arterial vascularization of the

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proximal epiphysis and the diaphysis of the fibula. Internat I Microsurg 2:49, 1980 Ponten B: The fascio-cutaneous flap: Its use in soft tissue defects of the lower leg. Br I Plast Surg 34 215, 1981 Cormack GC, Lamberty BGH: A classification of fasciocutaneous flaps according to their patterns of vascularization. Br I Plast Surg 37:80, 1984 Onishi K, Maruyama Y, Iwahira Y: Cutaneous and fascial vasculature of the leg: Anatomic study of fasciocutaneous vessels. I Reconstr Microsurg 2:181, 1986 Tolhurst DE, Haeseker B: Fasciocutaneous flaps in the axillary region. Br I Plast Surg 35:430, 1983 Acland RD, Schusterman M, G o d i n a M, et ah • The saphenous neurovascular free flap. Plast Reconstr Surg 67:763, 1981 Scheker LR, Kleinert H E , Hanel DP: The ipsilateral lateral a r m flap. 1 H a n d Surg 12A:665, 1987 Soutar DS, Scheker LR, Tanner NS, McGregor 1A: The radial forearm flap: A versatile m e t h o d for intraoral reconstruction. Br I Plast Surg 36 : 1, 1983 Urbaniak JR, Koman LA, G o l d n e r RD, et a h The vascularized cutaneous scapular flap. Plast Reconstr Surg 69 : 772, 1982

The authors thank David Olsen, M.D., for his assistance in the preparation of some of the anatomic specimens, Kell

Julliard for his assistance in the preparation of this text, and Media Services of the Christine M. Kleinert Institute for Hand and Micro Surgery for photography and illustration.

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CONCLUSIONS

The osteocutaneous fibula flap: an anatomic study.

Recent studies related to the fibula flap have disagreed regarding the anatomy of the cutaneous branches of the peroneal artery. To clarify this issue...
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