Surgical Radiologtc Anatomy
Surg Radiol Anat (t992) 14 : 319-323
Journal of Clinical Anatomy
© Springer-Verlag 1992
The ramification of the superficial branch of the superior gluteal artery. Anatomical basis of a new gluteus maximus myocutaneous flap
MY Kida l, Y Takami 2 and K Ezoe 2 IDepartment of Anatomy, 2Department of Plastic Surgery, Sapporo Medical College, S-1, W-I7 Chuo-ku, Sapporo 060, Japan
Summary. In order to design a new gluteus m a x i m u s m y o c u t a n e o u s flap, the ramification of the superficial branch of the superior gluteal artery was investigated in 56 sides of 33 Japanese cadavers. The superficial branch constantly divides into two main branches, which are called the a s c e n d i n g and t r a n s v e r s e branches in this study. Of the ascending and transverse branches, one or both usually give off at least one well developed division running on the u n d e r s u r f a c e of the gluteus maximus muscle (98.2%). This division, which is called the intermediate branch in this study, generally reaches the superior edge of the muscle giving off only a couple of muscular branches and pierces the muscle and its deep fascia to supply skin (83.6%). Perforators of the
Offprint requests" : MY Kida
intermediate branch constantly e m e r g e from the fascia near the middle or lower one-third point on a line extending from the middle of the iliac crest to the tip of the greater trochanter.
Les ramifications de la branehe superfieielle de l'art~re gluteale sup6rieure. Bases anatomiques d'un nouveau lambeau myocutane de muscle grand fessier
R6sum~. Dans le but de crder un nouveau l a m b e a u m y o c u t a n 6 de muscle grand fessier, les ramifications de la branche superficielle de l'art~re glutdale supdrieure ont 6t6 6tudi6es chez 33 sujets japonais (56 cot6s). La branche superficielle se divise de faqon constante en deux r a m e a u x p r i n c i p a u x , qui seront appel6s dans cette 6rude les branches ascendante et transverse.
De l'une de ces deux branches, ou parfois des deux, na{t souvent au moins un rameau bien ddvelopp6 courant sous le muscle grand fessier (98,2%). Cette branche de division, qui est nommde dans cette 6tude le rameau interm6diaire, atteint g6n6ralement la limite supdrieure du muscle, en abandonnant seulement quelques rameaux musculaires, et perfore te muscle et son fascia profond p o u r v a s c u l a r i s e r la peau (83,6%). Les branches perforantes du rameau intermddiaire traversent le fascia, de faqon constante, au niveau du milieu ou du tiers infdrienr d'une ligne tendue du milieu de la cr~te iliaque au sommet du grand trochanter.
Key words : Superior gluteat artery - - Superficial branch - - Ramification - - Gtuteus maximus myocntaneous flap
320
Construction of any graft or flap requires very accurate knowledge about the vascular supply. In the buttock it is commonly known that the superior gluteal artery separates into two main branches, namely the s u p e r f i c i a l and deep branches. However, the description of the ramification of the superficial branch is not sufficient to design myocutaneous flaps. Although Cormack and Lamberty [ 1] have described the ramification of the superficial branch of the superior gluteal artery in some detail to construct skin flaps, even their description is not sufficient for us to design a new flap [8, 9]. Therefore, we re-examined the ramification of the superficial branch. This study revealed some new findings about the ramification. Materials and methods In this study 56 sides of 33 Japanese c a d a v e r s (23 m a l e s and 10 females), aged 49 to 94 years, and fixed with 10% formic aldehyde and 60% alcohol solution were used. After incision of skin from the superior posterior iliac spine to the greater trochanter by way of the iliac crest and superior anterior iliac spine, the positions where perforators to skin from the superficial branch of the superior gluteal artery pierce the deep fascia were noted. Then the fascia was opened and the insertion of the gluteus maximus muscle was cut off to describe the main divisions of the superficial branch.
Description The superficial branch of the superior gluteal artery at first almost constantly divides into two main branches, one of which runs upward and the other laterally on the undersurface of the gluteus m a x i m u s muscle (Fig. 1). We called them the ascending and transverse branches,
MY Kida et al : Ramification of the superior branch of the superior gluteal artery
respectively. One or both of them almost always give off at least one w e l l - d e v e l o p e d division at their proximal portions. This division is called the intermediate branch in this study. The ascending branch ascends along the origin of the gluteus maximus to become a perforator supplying skin, giving off several short muscular branches, some of which are also finally perforators. The route of the ascending branch shows a tendency to follow a more lateral direction and its original distal part is sometimes not present. The transverse branch runs in a lateral or inferolateral direction on the undersurface of the gluteus maximus after its appearance from the supra piriformic foramen, and it finally reaches the part of the muscle overlying the tip of the greater trochanter. Its final branch frequently divides into some perforators supplying skin. However, when the superficial branch is not welldeveloped, the transverse branch runs in a superolateral direction and pierces the fascia superior to the usual position. Moreover, it can be deficient (5.4%). The transverse branch gives off several large muscular branches to the gtuteus maximus at nearly regular imervals along its entire length. They usually enter the musculature immediately after separation from the transverse branch, but one or two of t h e m are sometimes very well-developed and follow a long course. Because of the existence of such long muscular branches, the t r a n s v e r s e branch appears to divide into two or three. The transverse branch anastomoses with a branch from the inferior gluteal artery. Using this anastomosis the superficial branch of the superior gluteal artery on rare occasions compensates for complete deficiency of muscular branches to the gluteus maximus from the inferior gluteal artery (t.8%). The superficial branch usually supplies the upper
quarter or upper one-third of the muscle. Although the role of these two branches may be to supply the muscle, all their muscular branches can potentially reach skin, and many of them indeed supply skin. The intermediate branch runs superolaterally on the undersurface of the gluteus maximus muscle between the ascending and transverse branches. One or two intermediate branches were observed in the majority of examples, and there was a branch defect only in one example (Table 1). The origins o f i n t e r m e d i a t e branches are shown in Table 2, in which the three cases of complete defect of the transverse branch are excluded. The intermediate branch arises from its mother artery within the proximal half-part and then it gives off a couple of divisions at its proximal portion. Some of these divisions sometimes develop well to supply the gluteus medius muscle or directly to become perforators. The intermediate branch also produces one or two large muscular branches near the middle of its way to the superior edge of the gluteus maximus. Near the superior edge the terminal branch of the intermediate branch separates into a couple of well-developed perforators, which penetrate only the deep fascia or both the gluteus maximus and its fascia (Fig. 1). These perforators emerge from the fascia to supply
Table 1. Number of intermediate branches
Number No. of Cases Percentage
0 1 1.8
1 47 83.9
2 8 14.3
Total 56 100.0
Table 2. Origins of intermediate branches
Ascending branch Transverse branch Both branches Total
11 (21.2%) 39 (75.0%) 2 (3.8%) 52 (100,0%)
MY Kida et al : Ramification of the superior branch of the superior gluteal artery
skin within almost the same bounds in all cases. The intermediate branch following these descriptions was present in 83.6% of all the sides in which the intermediate branches were observed. The penetrating positions of well-developed perforators derived from the ascending, intermediate and transverse branches are generally aligned along the superior edge of the gluteus maximus. In particular, the positions where the perforators of the intermediate branch pierce the deep fascia can be well-defined using two landmarks, the middle of the iliac crest and the tip of the greater trochanter (Fig. 1). Namely, the penetrating positions are in the vicinity
of the middle or lower one-third point on a line stretching between the two landmarks. The ascending, intermediate and transverse branches have their own accompanying veins on both their sides. Discussion Cormack and Lamberty [1] described the ramifications of the superficial branch of the superior gtuteal artery and they divided the branch into three main divisions, the intermediate, anterior and p o s t e r i o r branches. These branches seem to con'espond to the ascending, intermediate and transverse branches of this study, respectively. We support
321
the description of the intermediate and posterior branches by Cormack and Lamberty [1], but not that of the anterior branch. In other words, their description is not anatomically applicable to e v e r y example in terms of the ramification of the superficial branch. The reason for this is thought to be that they did not consider variations of their anterior branch (the intermediate branch in the present study). Our study demonstrated that the intermediate branch varies in terms of both number and origin. Variations of the branch suggest m o r p h o l o g i c a l continuity, as is shown in Figure 2. This continuity can be interpreted as being due to competition for
Fig. 1 Two examples of the ramification of the superficial branch of the superior gluteal arte W running on the undersurface of the gluteus maximus muscle. A and T represent the ascending and transverse branches, respectively,. White stars mad black asterisks show the middle of the iliac crest and the tip of the greater trochanter, respectively, and both are connected with a line. Arrows point to the positions where perforators of the intermediate branch pierce the deep fascia near the superior edge of the gluteus maximus Deux exemples des ramifications de la branche superficielle de l'art6m glut6ale supdrieure courant sous Ia surface du muscle grand fessier, Les tettres A et T repr6sentent respectivement les branches ascendante et transverse. Les dtoiles blanches ettes astgrisques noirs montrent le milieu de la crete iliaque et le sommet du grand trochanter, entre lesquels est tendue une ligne. Lesflbches montrent les points o~ les attires perforantes de la branche intermddiaire traversent le fascia profond pros de la Iimite d'insertion supdrieure du muscle grand fessier
322
MY Kida et al : Ramification of the superior branch of the superior gluteai artery , ,,,,,,/,,,
A TYPE
PROTOTYPE
COMBINATION TYPE
PROTOTYPE
T TYPE
i
A
2,
/ A
I
1.0%
2.0%
T
A//320.0%
A,=
ly
A
/
14.3%
T
A
2
4.1%
A
T
?
20,4% 3
T
~34.1%
A
2.0%1 A 33
i
T
T
A
0.0%
2.0%
/ ,
A
8.2%
6.1%
//
T
2.0%
,~2,
A
T
A
1.0%
T
A
2
32.7%
/
T
T
Fig. 2 Diagram showing morphological continuity of the intermediate branches. The prototype has no intermediate branch. A and T types are divided in terms of the origin of intermediate branches, namely the branches of A type derive from the ascending branch and those of T type from the transverse branch. The numbers 2 and 3 represent the middle and lower one-third points on a line extending from the middle of the iliac crest to the tip of the greater trochanter, respectively, where perforators of the intermediate branch pierce the deep fascia. An example which seems to be a combination of the A and T types was observed. Any combination of A and T types could theoretically appear on condition that distributions of all intermediate branches do not cause inversion in their order from superior to inferior Diagramme montrant la continuit6 morphologique des branches interm6diaires. Le prototype n'a pas de branche interm6diaire. Les types A et T sont class6es en fonction de l'origine des branches interm~diaires, qui proviennent de la branche ascendante dans le type A, et de la branche transverse dans te type T. Les nombres 2 et 3 reprdsentent le milieu et le tiers inf6rieur d'une ligne tendue dn milieu de la crete iliaque au sommet dn grand trochanter, off les perforantes de la branche interm6diaim traversent le fascia profond. Un exemple, qui semble ~tre une combinaison des types A et T a ~t~ observ6e. Toute combinaison des types A e t Tpeut thdoriquement Otre rdalis~e ~t condition que la distribution des branches intermddiaires reste toujours ordonnde de haut en bas
increasing blood supply demands during growth in the distributions of the a s c e n d i n g and t r a n s v e r s e branches. Such competition can be also noticed between distributions to the gluteus m a x i m u s of the superior and inferior gluteal arteries. Therefore, the ramification of the superficial branch is thought to be i n f l u e n c e d by the d e g r e e o f development of the branch. Clinically, it can be considered that the superficial branch generally divides into three, since the branch appeared to do so in 73.2% of the examples of this study. However, there were cases in which the superficial branch did not appear to divide into three divisions (26.8%). Such variations cannot be ignored f r o m the view point of clinical applications. More accurate descriptions and anatomical interpreta-
tion of the variations are important in the construction of buttock flaps. Concerning the design of our new gluteus m a x i m u s m y o c u t a n e o u s flap, it is best to use the intermediate branch for the following reasons: 1) the intermediate branch is almost always present and usually has one or more well-developed perforators supplying skin; 2) the positions where the perforators pierce the deep fascia can be well defined by surface anatomy; 3) the intermediate branch has fewer large muscular b r a n c h e s than the o t h e r two branches of tile superficial branch, and it runs e x t e n s i v e l y on the undersurface of the gluteus maximus. Therefore, it is simple and easy to make a long flap stalk including both arteries and veins. On tl~e basis of these anatomical findings we have used, in 2 cases, this perfo-
rating artery of the intermediate branch as the vascular pedicle of a free flap [9]. In both cases, we designed a new flap on the superolateral skin of the buttock (8.0 cm x 4.5 cm & 8.5 c m x 5.0 cm), and l o n g (about 3 cm) flap stalks including large arteries in diameter (more than 1.5 ram) were available. Our new flaps were successfully transferred to post-operative defects following facial cancer. Moreover, construction of the new myocutaneous flap did not cause any functional damage to the gluteus muscle because only a little of the musculature was cut off with the vascular pedicle (stalk) due to flap elevation. The perforators pierce the musculature near the superior edge of the gluteus maximus when they penetrate the muscle. Therefore, the flap is practically a type of perforator-
MY Kida et al : Ramification of the superior branch of the superior gluteal artery
based flap [3, 4]. There have been several reports of a gtuteus maximus myocutaneous free flap [2, 5, 6, 7]. However, such myocutaneous flaps cause functional damage of the gluteus maximus muscle. Our new myocutaneous flap caused no functional loss of the muscle. This is the most remarkable characteristic of our flap and it is very useful as a donor flap.
References 1.
2.
3.
4.
Acknowledgment. We are grateful to Prof. Y. Dodo, Sapporo Medical College, for his advice and Prof. L Patrick Barton, Tokyo Medical College, for grammatical review of the manuscript.
5.
Cormack GC, Lamberty BGH (1986) The arterial anatomy of skin flaps. Churchill Livingstone, London, pp 198-205 Fujino T, Harashima T, Aoyagi FL (1975) Reconstruction for aplasia of the breast and pectoral region by microvascular transfer of a free flap from the buttock. Plast R e c o n s t r Surg 56 : 178 Koshima I, Morignchi T, Soeda S, Tanaka H, U m e d a N (1992) Free thin paraumbilical perforator-based flaps. Annals Plast Surg 29 : 12-17 Koshima I, Soeda S (1989) Inferior epigastric skin flaps without rectus abdominis muscle. Br J Plast Surg 42 : 645-648 Mathes S J, Nahai F (t979) Clinical atlas of muscle and musculocutaneous flaps, CV Mosby, London, pp 91-95
323 6.
7.
8.
9.
Shaw WW (1983) Breast reconstruction by superior gluteal microvascutar free flaps without siticone implants. Plast Reconstr Surg 72 : 490 Shaw WW (1984) Microvascutar free flap breast reconstruction. Clin Plast Surg 1 t : 333 Takami Y, Kida M (I991) A gluteus muscle perforating artery flap based on the superior gluteal artery. Korean Plast Reconstr Sm'g abstract, p 87 Takami Y, Yamaguchi T, Hata K, Yamaguchi Y, Abe S, Fujita T, Ezoe K, Kida M (1990) A gluteus m a x i m u s muscle perforating artery flap based on the superior gluteal artery. Japan J Plast Reconstr Surg 33 : 843-848
Received May 12, 1992 / Accepted in final form September 30, 1992
Surg Radiol Anat (t992) 14 : 319-323
Journal of Clinical Anatomy
© Springer-Verlag 1992
The ramification of the superficial branch of the superior gluteal artery. Anatomical basis of a new gluteus maximus myocutaneous flap
MY Kida l, Y Takami 2 and K Ezoe 2 IDepartment of Anatomy, 2Department of Plastic Surgery, Sapporo Medical College, S-1, W-I7 Chuo-ku, Sapporo 060, Japan
Summary. In order to design a new gluteus m a x i m u s m y o c u t a n e o u s flap, the ramification of the superficial branch of the superior gluteal artery was investigated in 56 sides of 33 Japanese cadavers. The superficial branch constantly divides into two main branches, which are called the a s c e n d i n g and t r a n s v e r s e branches in this study. Of the ascending and transverse branches, one or both usually give off at least one well developed division running on the u n d e r s u r f a c e of the gluteus maximus muscle (98.2%). This division, which is called the intermediate branch in this study, generally reaches the superior edge of the muscle giving off only a couple of muscular branches and pierces the muscle and its deep fascia to supply skin (83.6%). Perforators of the
Offprint requests" : MY Kida
intermediate branch constantly e m e r g e from the fascia near the middle or lower one-third point on a line extending from the middle of the iliac crest to the tip of the greater trochanter.
Les ramifications de la branehe superfieielle de l'art~re gluteale sup6rieure. Bases anatomiques d'un nouveau lambeau myocutane de muscle grand fessier
R6sum~. Dans le but de crder un nouveau l a m b e a u m y o c u t a n 6 de muscle grand fessier, les ramifications de la branche superficielle de l'art~re glutdale supdrieure ont 6t6 6tudi6es chez 33 sujets japonais (56 cot6s). La branche superficielle se divise de faqon constante en deux r a m e a u x p r i n c i p a u x , qui seront appel6s dans cette 6rude les branches ascendante et transverse.
De l'une de ces deux branches, ou parfois des deux, na{t souvent au moins un rameau bien ddvelopp6 courant sous le muscle grand fessier (98,2%). Cette branche de division, qui est nommde dans cette 6tude le rameau interm6diaire, atteint g6n6ralement la limite supdrieure du muscle, en abandonnant seulement quelques rameaux musculaires, et perfore te muscle et son fascia profond p o u r v a s c u l a r i s e r la peau (83,6%). Les branches perforantes du rameau intermddiaire traversent le fascia, de faqon constante, au niveau du milieu ou du tiers infdrienr d'une ligne tendue du milieu de la cr~te iliaque au sommet du grand trochanter.
Key words : Superior gluteat artery - - Superficial branch - - Ramification - - Gtuteus maximus myocntaneous flap
320
Construction of any graft or flap requires very accurate knowledge about the vascular supply. In the buttock it is commonly known that the superior gluteal artery separates into two main branches, namely the s u p e r f i c i a l and deep branches. However, the description of the ramification of the superficial branch is not sufficient to design myocutaneous flaps. Although Cormack and Lamberty [ 1] have described the ramification of the superficial branch of the superior gluteal artery in some detail to construct skin flaps, even their description is not sufficient for us to design a new flap [8, 9]. Therefore, we re-examined the ramification of the superficial branch. This study revealed some new findings about the ramification. Materials and methods In this study 56 sides of 33 Japanese c a d a v e r s (23 m a l e s and 10 females), aged 49 to 94 years, and fixed with 10% formic aldehyde and 60% alcohol solution were used. After incision of skin from the superior posterior iliac spine to the greater trochanter by way of the iliac crest and superior anterior iliac spine, the positions where perforators to skin from the superficial branch of the superior gluteal artery pierce the deep fascia were noted. Then the fascia was opened and the insertion of the gluteus maximus muscle was cut off to describe the main divisions of the superficial branch.
Description The superficial branch of the superior gluteal artery at first almost constantly divides into two main branches, one of which runs upward and the other laterally on the undersurface of the gluteus m a x i m u s muscle (Fig. 1). We called them the ascending and transverse branches,
MY Kida et al : Ramification of the superior branch of the superior gluteal artery
respectively. One or both of them almost always give off at least one w e l l - d e v e l o p e d division at their proximal portions. This division is called the intermediate branch in this study. The ascending branch ascends along the origin of the gluteus maximus to become a perforator supplying skin, giving off several short muscular branches, some of which are also finally perforators. The route of the ascending branch shows a tendency to follow a more lateral direction and its original distal part is sometimes not present. The transverse branch runs in a lateral or inferolateral direction on the undersurface of the gluteus maximus after its appearance from the supra piriformic foramen, and it finally reaches the part of the muscle overlying the tip of the greater trochanter. Its final branch frequently divides into some perforators supplying skin. However, when the superficial branch is not welldeveloped, the transverse branch runs in a superolateral direction and pierces the fascia superior to the usual position. Moreover, it can be deficient (5.4%). The transverse branch gives off several large muscular branches to the gtuteus maximus at nearly regular imervals along its entire length. They usually enter the musculature immediately after separation from the transverse branch, but one or two of t h e m are sometimes very well-developed and follow a long course. Because of the existence of such long muscular branches, the t r a n s v e r s e branch appears to divide into two or three. The transverse branch anastomoses with a branch from the inferior gluteal artery. Using this anastomosis the superficial branch of the superior gluteal artery on rare occasions compensates for complete deficiency of muscular branches to the gluteus maximus from the inferior gluteal artery (t.8%). The superficial branch usually supplies the upper
quarter or upper one-third of the muscle. Although the role of these two branches may be to supply the muscle, all their muscular branches can potentially reach skin, and many of them indeed supply skin. The intermediate branch runs superolaterally on the undersurface of the gluteus maximus muscle between the ascending and transverse branches. One or two intermediate branches were observed in the majority of examples, and there was a branch defect only in one example (Table 1). The origins o f i n t e r m e d i a t e branches are shown in Table 2, in which the three cases of complete defect of the transverse branch are excluded. The intermediate branch arises from its mother artery within the proximal half-part and then it gives off a couple of divisions at its proximal portion. Some of these divisions sometimes develop well to supply the gluteus medius muscle or directly to become perforators. The intermediate branch also produces one or two large muscular branches near the middle of its way to the superior edge of the gluteus maximus. Near the superior edge the terminal branch of the intermediate branch separates into a couple of well-developed perforators, which penetrate only the deep fascia or both the gluteus maximus and its fascia (Fig. 1). These perforators emerge from the fascia to supply
Table 1. Number of intermediate branches
Number No. of Cases Percentage
0 1 1.8
1 47 83.9
2 8 14.3
Total 56 100.0
Table 2. Origins of intermediate branches
Ascending branch Transverse branch Both branches Total
11 (21.2%) 39 (75.0%) 2 (3.8%) 52 (100,0%)
MY Kida et al : Ramification of the superior branch of the superior gluteal artery
skin within almost the same bounds in all cases. The intermediate branch following these descriptions was present in 83.6% of all the sides in which the intermediate branches were observed. The penetrating positions of well-developed perforators derived from the ascending, intermediate and transverse branches are generally aligned along the superior edge of the gluteus maximus. In particular, the positions where the perforators of the intermediate branch pierce the deep fascia can be well-defined using two landmarks, the middle of the iliac crest and the tip of the greater trochanter (Fig. 1). Namely, the penetrating positions are in the vicinity
of the middle or lower one-third point on a line stretching between the two landmarks. The ascending, intermediate and transverse branches have their own accompanying veins on both their sides. Discussion Cormack and Lamberty [1] described the ramifications of the superficial branch of the superior gtuteal artery and they divided the branch into three main divisions, the intermediate, anterior and p o s t e r i o r branches. These branches seem to con'espond to the ascending, intermediate and transverse branches of this study, respectively. We support
321
the description of the intermediate and posterior branches by Cormack and Lamberty [1], but not that of the anterior branch. In other words, their description is not anatomically applicable to e v e r y example in terms of the ramification of the superficial branch. The reason for this is thought to be that they did not consider variations of their anterior branch (the intermediate branch in the present study). Our study demonstrated that the intermediate branch varies in terms of both number and origin. Variations of the branch suggest m o r p h o l o g i c a l continuity, as is shown in Figure 2. This continuity can be interpreted as being due to competition for
Fig. 1 Two examples of the ramification of the superficial branch of the superior gluteal arte W running on the undersurface of the gluteus maximus muscle. A and T represent the ascending and transverse branches, respectively,. White stars mad black asterisks show the middle of the iliac crest and the tip of the greater trochanter, respectively, and both are connected with a line. Arrows point to the positions where perforators of the intermediate branch pierce the deep fascia near the superior edge of the gluteus maximus Deux exemples des ramifications de la branche superficielle de l'art6m glut6ale supdrieure courant sous Ia surface du muscle grand fessier, Les tettres A et T repr6sentent respectivement les branches ascendante et transverse. Les dtoiles blanches ettes astgrisques noirs montrent le milieu de la crete iliaque et le sommet du grand trochanter, entre lesquels est tendue une ligne. Lesflbches montrent les points o~ les attires perforantes de la branche intermddiaire traversent le fascia profond pros de la Iimite d'insertion supdrieure du muscle grand fessier
322
MY Kida et al : Ramification of the superior branch of the superior gluteai artery , ,,,,,,/,,,
A TYPE
PROTOTYPE
COMBINATION TYPE
PROTOTYPE
T TYPE
i
A
2,
/ A
I
1.0%
2.0%
T
A//320.0%
A,=
ly
A
/
14.3%
T
A
2
4.1%
A
T
?
20,4% 3
T
~34.1%
A
2.0%1 A 33
i
T
T
A
0.0%
2.0%
/ ,
A
8.2%
6.1%
//
T
2.0%
,~2,
A
T
A
1.0%
T
A
2
32.7%
/
T
T
Fig. 2 Diagram showing morphological continuity of the intermediate branches. The prototype has no intermediate branch. A and T types are divided in terms of the origin of intermediate branches, namely the branches of A type derive from the ascending branch and those of T type from the transverse branch. The numbers 2 and 3 represent the middle and lower one-third points on a line extending from the middle of the iliac crest to the tip of the greater trochanter, respectively, where perforators of the intermediate branch pierce the deep fascia. An example which seems to be a combination of the A and T types was observed. Any combination of A and T types could theoretically appear on condition that distributions of all intermediate branches do not cause inversion in their order from superior to inferior Diagramme montrant la continuit6 morphologique des branches interm6diaires. Le prototype n'a pas de branche interm6diaire. Les types A et T sont class6es en fonction de l'origine des branches interm~diaires, qui proviennent de la branche ascendante dans le type A, et de la branche transverse dans te type T. Les nombres 2 et 3 reprdsentent le milieu et le tiers inf6rieur d'une ligne tendue dn milieu de la crete iliaque au sommet dn grand trochanter, off les perforantes de la branche interm6diaim traversent le fascia profond. Un exemple, qui semble ~tre une combinaison des types A et T a ~t~ observ6e. Toute combinaison des types A e t Tpeut thdoriquement Otre rdalis~e ~t condition que la distribution des branches intermddiaires reste toujours ordonnde de haut en bas
increasing blood supply demands during growth in the distributions of the a s c e n d i n g and t r a n s v e r s e branches. Such competition can be also noticed between distributions to the gluteus m a x i m u s of the superior and inferior gluteal arteries. Therefore, the ramification of the superficial branch is thought to be i n f l u e n c e d by the d e g r e e o f development of the branch. Clinically, it can be considered that the superficial branch generally divides into three, since the branch appeared to do so in 73.2% of the examples of this study. However, there were cases in which the superficial branch did not appear to divide into three divisions (26.8%). Such variations cannot be ignored f r o m the view point of clinical applications. More accurate descriptions and anatomical interpreta-
tion of the variations are important in the construction of buttock flaps. Concerning the design of our new gluteus m a x i m u s m y o c u t a n e o u s flap, it is best to use the intermediate branch for the following reasons: 1) the intermediate branch is almost always present and usually has one or more well-developed perforators supplying skin; 2) the positions where the perforators pierce the deep fascia can be well defined by surface anatomy; 3) the intermediate branch has fewer large muscular b r a n c h e s than the o t h e r two branches of tile superficial branch, and it runs e x t e n s i v e l y on the undersurface of the gluteus maximus. Therefore, it is simple and easy to make a long flap stalk including both arteries and veins. On tl~e basis of these anatomical findings we have used, in 2 cases, this perfo-
rating artery of the intermediate branch as the vascular pedicle of a free flap [9]. In both cases, we designed a new flap on the superolateral skin of the buttock (8.0 cm x 4.5 cm & 8.5 c m x 5.0 cm), and l o n g (about 3 cm) flap stalks including large arteries in diameter (more than 1.5 ram) were available. Our new flaps were successfully transferred to post-operative defects following facial cancer. Moreover, construction of the new myocutaneous flap did not cause any functional damage to the gluteus muscle because only a little of the musculature was cut off with the vascular pedicle (stalk) due to flap elevation. The perforators pierce the musculature near the superior edge of the gluteus maximus when they penetrate the muscle. Therefore, the flap is practically a type of perforator-
MY Kida et al : Ramification of the superior branch of the superior gluteal artery
based flap [3, 4]. There have been several reports of a gtuteus maximus myocutaneous free flap [2, 5, 6, 7]. However, such myocutaneous flaps cause functional damage of the gluteus maximus muscle. Our new myocutaneous flap caused no functional loss of the muscle. This is the most remarkable characteristic of our flap and it is very useful as a donor flap.
References 1.
2.
3.
4.
Acknowledgment. We are grateful to Prof. Y. Dodo, Sapporo Medical College, for his advice and Prof. L Patrick Barton, Tokyo Medical College, for grammatical review of the manuscript.
5.
Cormack GC, Lamberty BGH (1986) The arterial anatomy of skin flaps. Churchill Livingstone, London, pp 198-205 Fujino T, Harashima T, Aoyagi FL (1975) Reconstruction for aplasia of the breast and pectoral region by microvascular transfer of a free flap from the buttock. Plast R e c o n s t r Surg 56 : 178 Koshima I, Morignchi T, Soeda S, Tanaka H, U m e d a N (1992) Free thin paraumbilical perforator-based flaps. Annals Plast Surg 29 : 12-17 Koshima I, Soeda S (1989) Inferior epigastric skin flaps without rectus abdominis muscle. Br J Plast Surg 42 : 645-648 Mathes S J, Nahai F (t979) Clinical atlas of muscle and musculocutaneous flaps, CV Mosby, London, pp 91-95
323 6.
7.
8.
9.
Shaw WW (1983) Breast reconstruction by superior gluteal microvascutar free flaps without siticone implants. Plast Reconstr Surg 72 : 490 Shaw WW (1984) Microvascutar free flap breast reconstruction. Clin Plast Surg 1 t : 333 Takami Y, Kida M (I991) A gluteus muscle perforating artery flap based on the superior gluteal artery. Korean Plast Reconstr Sm'g abstract, p 87 Takami Y, Yamaguchi T, Hata K, Yamaguchi Y, Abe S, Fujita T, Ezoe K, Kida M (1990) A gluteus m a x i m u s muscle perforating artery flap based on the superior gluteal artery. Japan J Plast Reconstr Surg 33 : 843-848
Received May 12, 1992 / Accepted in final form September 30, 1992
