Journal of Plastic, Reconstructive & Aesthetic Surgery (2015) 68, 1417e1424
Rotation arc of pedicled anterolateral thigh flap for abdominal wall reconstruction: How far can it reach? Motoki Tamai a, Tomohisa Nagasao a,*, Takanori Miki b, Yusuke Hamamoto a, Testukuni Kogure a, Yoshio Tanaka a a Department of Plastic and Reconstructive Surgery, Faculty of Medicine/Graduate School of Medicine, Kagawa University, Takamatsu, Kagawa, Japan b Department of Anatomy and Neurobiology, Faculty of Medicine/Graduate School of Medicine, Kagawa University, Takamatsu, Kagawa, Japan
Received 21 February 2015; accepted 12 June 2015
KEYWORDS Anterolateral thigh flap; Flap; Abdominal reconstruction; Pedicle; Abdominal wall; Rotation arc
Summary Purpose: The aim of this study was to elucidate the extent to which pedicled anterolateral thigh (ALT) flaps can reach in reconstruction of abdominal wall defects. Methods: A total of 60 pedicled ALT flaps were raised from cadavers and were experimentally transferred to the abdominal region. The distance between the umbilicus and the most cranial point of the flap after transfer was defined as cranially reachable distance (CRD). Three issues were evaluated: (1) the difference in the CRD when the flap pedicle was positioned superficial or deep into the rectus femoris (RF) and sartorius (SA) muscles; (2) the difference in the CRD in those cases where the main artery of RF arises from the descending branch of the lateral femoral circumflex artery, and is preserved or severed; and (3) maximum values of CRD. Results: (1) CRD was significantly greater when the pedicle was passed deep into the muscles (2.5 3.8 SD cm) compared with superficial (5.8 3.3 SD cm), indicating placement of pedicles beneath the two muscles enables additional extension. (2) CRD was significantly greater for the severed condition (0.3 4.0 SD cm) than for the preserved condition (3.3 4.1 SD cm), indicating severing the main artery of RF allows additional extension. (3) Out of the 60 specimens, the CRD was cranial to the umbilicus in 17 flaps, indicating pedicled ALT flaps can reach the umbilicus in less than one-third (17/60) of cases.
* Corresponding author. Department of Plastic and Reconstructive Surgery, Faculty of Medicine/Graduate School of Medicine, Kagawa University, Kagawa Prefecture, Kida County, Miki-Cho, Ikenobe 1750-1, Japan. Tel.: þ81 87 891 2198; fax: þ81 87 891 2199. E-mail address: [email protected] (T. Nagasao). http://dx.doi.org/10.1016/j.bjps.2015.06.010 1748-6815/ª 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
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M. Tamai et al. Conclusion: Pedicled ALT flaps can reliably reach regions inferior to the umbilicus. However, for defects superior to the umbilicus, other reconstructive options should be considered. ª 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Introduction Full-thickness abdominal wall defects may arise following injury or tumor resection. When the defects cannot be directly closed, coverage requires flaps e such as external oblique abdominal muscle,1 groin,2e4 tensor fascia lata (TFL),5e7 and anterior lateral thigh.8e13 Among these reconstructive options, this study focuses on the anterolateral thigh (ALT) flap, which can achieve simultaneous reconstruction of the skin and fascial defect with limited donor morbidity. The ALT flap can be transferred to the abdomen in two ways: as a pedicled flap or free flap. The former is simpler, because it avoids vascular anastomoses and saves operation time and cost. However, pedicled flaps cannot cover the defects present in the upper abdominal region. In that case, the operating team must plan the need for a free flap in advance and not during surgery. For effective performance, the operator should be able to predict whether the defect could be covered with a pedicled ALT flap. Prior knowledge on how far a pedicled ALT flap can reach in the abdominal region is essential in making such a prediction. Hence, this study aims to elucidate the extent to which pedicled ALT flaps can reach in the cranial direction.
Materials and methods Experimental conditions Specimens Of the 62 preserved lower limbs (32 male and 30 female) donated to the department of anatomy at our institute for ALT dissection, two (both female) were unsuitable, because of absence of perforators. Therefore, 60 ALT flaps raised from the remaining 60 limbs were involved in this study (Figure 1). Flap elevation The skin and deep fascia were incised in the anterior midline of the middle-third region of each cadaver’s thigh medial to the anticipated line of perforators. The subfascial dissection was developed to identify the perforators. Having determined the largest perforator, a skin paddle was then designed symmetrically with the perforator at its center point (Figure 2). The length of the skin island was arbitrarily determined to be one-third of the length of the line drawn from the anterior superior iliac spine (ASIS) to the superolateral margin of the patella. For instance, for a thigh whose distance between the ASIS and the
superolateral margin of the patella was 39 cm, the length of the skin paddle was set as 13 cm. The more distal the main perforator, the more distal is the flap and, consequently, the longer its arc of rotation. Distances between the ASIS and the superolateral margin of the patella were 41.8 2.8 and 37.1 1.9 SD cm for male (n Z 32) and female limbs (n Z 28), respectively. Dissection proceeded along the main perforator to its source from the descending branch of the lateral circumflex femoral artery. The isolation of the vascular pedicle enables mobilization of the flap in the cranial direction. Measurement of reachable distances After complete mobilization of the pedicle, flaps were transferred to the abdominal region through a subcutaneous tunnel made in the inguinal region. The transfer was performed in the cranial direction as far as possible, avoiding excessive tension on their vascular pedicles. The distance between the most cranial point of the flap (i.e., the tip of the skin paddle) and the umbilicus was defined as cranially reachable distance (CRD). The measured distances were positive when the tips of the skin paddles were extended beyond the umbilicus, and negative when they did not reach the umbilicus. For example, when the tip of the skin paddle reached a point more cranial than the umbilicus by 5 cm, CRD for that flap was evaluated as þ5 cm, but when it fell short of the umbilicus by 2 cm, CRD was evaluated as 2 cm. Hence, CRD is a parameter that indicates how far a flap can reach in the cranial direction. That is, the greater the CRD, the more cranially the flap can be transferred.
Data evaluation The data collected in the above-described measurement system were evaluated to clarify the following three issues. Influence of pedicle positioning on reachable distances In transferring pedicled ALT flaps, the vascular pedicles can be positioned using two approaches. In the first approach, vascular pedicles were positioned superficial to the rectus femoris (RF) and sartorius (SA) muscles (Figure 3A). This method was called superficial positioning. In the second approach, vascular pedicles were placed beneath the two muscles (Figure 4) to avoid hindrance of the pedicles by the two muscles during cranial transfer. This method was called deep positioning (Figure 3B). Each of those 60 flaps was transferred to the abdominal region via any of the two approaches, and CRD was measured for each transfer. Thereafter, the data for the two different approaches were compared.
Rotation arc of pedicled anterolateral thigh flap
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Figure 1 A clinical case of abdominal wall reconstruction using an ALT flap. To provide coverage for a defect in the right inferior abdominal region (Left Above), an ALT flap was raised from the right thigh and was transferred to the abdominal region (Right Above and Left Below). Thereby, successful coverage of the defect was achieved (Right Below).
Influence of anatomical variations on reachable distances Vascular pedicles of ALT flaps present two anatomical types. In the first type, the feeding artery of the RF muscle directly branches out from the lateral circumflex femoral artery (Figure 5 Left). This anatomical type is defined as
Type 1. In the second type, the feeding artery of the RF muscle arises more inferiorly from the descending branch of the lateral femoral circumflex artery (Figure 5 Right), and hence creates a pivot point for the pedicle more distally in the thigh. This anatomical type is defined as Type
Figure 2 Design of the flap. The flap was designed on the thigh so that the length of the skin paddle was one-third of the distance between the anterior superior iliac spine and the lateral margin of the patella.
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Figure 3 In transferring the flap to the abdominal region, the vascular pedicle was placed in two ways. (Left) In the first method, the vascular pedicle was positioned on the ventral side of the rectus femoris muscle (R) and sartorius muscle (S). This manner of positioning was named Superficial Positioning. (Right) In the second method, the vascular pedicle was positioned on the dorsal side of the two muscles. This manner of positioning was named Deep Positioning.
2. With reference to these anatomical types, evaluation was conducted with regard to the following issues: Ratios of anatomical types. In order to evaluate occurrence ratios, the number of specimens belonging to each type was counted for the 60 lower limbs. Relationship between anatomical types and CRD. For limbs presenting Type 1 anatomy, a vascular pedicle can be
extended to its maximum length without severing the feeding artery of the RF muscle. ALT flaps raised from these lower limbs were simply transferred to the abdominal region as shown in Figure 6. For lower limbs presenting Type 2 anatomy, transfer of ALT flaps is restricted by the main artery of the RF muscle. This can be eliminated by severing the artery, and further extension can be achieved. On considering this, CRD was measured for lower limbs with Type 2 anatomy under two
Figure 4 In Deep Positioning, the skin paddle and the vascular pedicle were transferred through the space beneath the rectus femoris and sartorius muscles to achieve additional extension in the cranial direction.
Rotation arc of pedicled anterolateral thigh flap
Figure 5 The structure of ALT pedicles is complicated by the existence of two anatomical types. (Left) In Type 1, the feeding artery of the rectus femoris muscle comes from the horizontal branch of the lateral femoral circumflex artery. (Right) In Type 2, the feeding artery of the rectus femoris muscle comes from the descending branch of the lateral circumflex femoral artery.
conditions. In the first condition, which is termed RFbranch preserving condition, the main artery of RF was preserved (Figure 7 Top Right); in the second condition, which was termed RF-branch severing condition, RF’s main artery was severed to achieve additional advancement of the flap (Figure 7 Bottom Right). In order to evaluate the effect of severing RF’s main artery, CRDs were compared between the two conditions. Evaluation of maximum reach of ALT flaps As stated in the previous paragraph, the conditions under which CDRs are maximized differ depending upon the anatomical type of the operated limb. When an ALT flap is raised from a limb with Type 1 anatomy, CRD can be maximized without severing the feeding artery of the RF muscle; when the flap elevation is conducted on a limb with Type 2 anatomy, the feeding artery of the RF muscle needs
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Figure 7 In lower limbs with Type 2 anatomy, transfer of the flap is limited by the feeding artery of the rectus femoris muscle, which comes from the descending branch of the lateral circumflex femoral artery. CRD was evaluated in two conditions. In the first condition, the feeding artery was preserved (RF-branch preserving condition); in the second condition, the feeding artery was severed to achieve additional extension of the flap.
to be severed to maximize CRD. After performing appropriate maneuvers according to the anatomical types, CRD was measured for the 60 ALT flaps. Thereafter, the number of flaps that could reach above the umbilicus (i.e., CRD > 0) was determined.
Statistical analyses Comparison of CRD between superior positioning style and deep positioning style was done with a paired t-test. Comparison of CRD between the anatomical types was done with one-way analysis of variance (ANOVA) with post hoc Turkey honestly significance differences (HSD). Stata SE 13.1 (StataCorp LP, College Station, TX, USA) was used for all analyses. p-values
Rotation arc of pedicled anterolateral thigh flap for abdominal wall reconstruction: How far can it reach? Motoki Tamai a, Tomohisa Nagasao a,*, Takanori Miki b, Yusuke Hamamoto a, Testukuni Kogure a, Yoshio Tanaka a a Department of Plastic and Reconstructive Surgery, Faculty of Medicine/Graduate School of Medicine, Kagawa University, Takamatsu, Kagawa, Japan b Department of Anatomy and Neurobiology, Faculty of Medicine/Graduate School of Medicine, Kagawa University, Takamatsu, Kagawa, Japan
Received 21 February 2015; accepted 12 June 2015
KEYWORDS Anterolateral thigh flap; Flap; Abdominal reconstruction; Pedicle; Abdominal wall; Rotation arc
Summary Purpose: The aim of this study was to elucidate the extent to which pedicled anterolateral thigh (ALT) flaps can reach in reconstruction of abdominal wall defects. Methods: A total of 60 pedicled ALT flaps were raised from cadavers and were experimentally transferred to the abdominal region. The distance between the umbilicus and the most cranial point of the flap after transfer was defined as cranially reachable distance (CRD). Three issues were evaluated: (1) the difference in the CRD when the flap pedicle was positioned superficial or deep into the rectus femoris (RF) and sartorius (SA) muscles; (2) the difference in the CRD in those cases where the main artery of RF arises from the descending branch of the lateral femoral circumflex artery, and is preserved or severed; and (3) maximum values of CRD. Results: (1) CRD was significantly greater when the pedicle was passed deep into the muscles (2.5 3.8 SD cm) compared with superficial (5.8 3.3 SD cm), indicating placement of pedicles beneath the two muscles enables additional extension. (2) CRD was significantly greater for the severed condition (0.3 4.0 SD cm) than for the preserved condition (3.3 4.1 SD cm), indicating severing the main artery of RF allows additional extension. (3) Out of the 60 specimens, the CRD was cranial to the umbilicus in 17 flaps, indicating pedicled ALT flaps can reach the umbilicus in less than one-third (17/60) of cases.
* Corresponding author. Department of Plastic and Reconstructive Surgery, Faculty of Medicine/Graduate School of Medicine, Kagawa University, Kagawa Prefecture, Kida County, Miki-Cho, Ikenobe 1750-1, Japan. Tel.: þ81 87 891 2198; fax: þ81 87 891 2199. E-mail address: [email protected] (T. Nagasao). http://dx.doi.org/10.1016/j.bjps.2015.06.010 1748-6815/ª 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
1418
M. Tamai et al. Conclusion: Pedicled ALT flaps can reliably reach regions inferior to the umbilicus. However, for defects superior to the umbilicus, other reconstructive options should be considered. ª 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Introduction Full-thickness abdominal wall defects may arise following injury or tumor resection. When the defects cannot be directly closed, coverage requires flaps e such as external oblique abdominal muscle,1 groin,2e4 tensor fascia lata (TFL),5e7 and anterior lateral thigh.8e13 Among these reconstructive options, this study focuses on the anterolateral thigh (ALT) flap, which can achieve simultaneous reconstruction of the skin and fascial defect with limited donor morbidity. The ALT flap can be transferred to the abdomen in two ways: as a pedicled flap or free flap. The former is simpler, because it avoids vascular anastomoses and saves operation time and cost. However, pedicled flaps cannot cover the defects present in the upper abdominal region. In that case, the operating team must plan the need for a free flap in advance and not during surgery. For effective performance, the operator should be able to predict whether the defect could be covered with a pedicled ALT flap. Prior knowledge on how far a pedicled ALT flap can reach in the abdominal region is essential in making such a prediction. Hence, this study aims to elucidate the extent to which pedicled ALT flaps can reach in the cranial direction.
Materials and methods Experimental conditions Specimens Of the 62 preserved lower limbs (32 male and 30 female) donated to the department of anatomy at our institute for ALT dissection, two (both female) were unsuitable, because of absence of perforators. Therefore, 60 ALT flaps raised from the remaining 60 limbs were involved in this study (Figure 1). Flap elevation The skin and deep fascia were incised in the anterior midline of the middle-third region of each cadaver’s thigh medial to the anticipated line of perforators. The subfascial dissection was developed to identify the perforators. Having determined the largest perforator, a skin paddle was then designed symmetrically with the perforator at its center point (Figure 2). The length of the skin island was arbitrarily determined to be one-third of the length of the line drawn from the anterior superior iliac spine (ASIS) to the superolateral margin of the patella. For instance, for a thigh whose distance between the ASIS and the
superolateral margin of the patella was 39 cm, the length of the skin paddle was set as 13 cm. The more distal the main perforator, the more distal is the flap and, consequently, the longer its arc of rotation. Distances between the ASIS and the superolateral margin of the patella were 41.8 2.8 and 37.1 1.9 SD cm for male (n Z 32) and female limbs (n Z 28), respectively. Dissection proceeded along the main perforator to its source from the descending branch of the lateral circumflex femoral artery. The isolation of the vascular pedicle enables mobilization of the flap in the cranial direction. Measurement of reachable distances After complete mobilization of the pedicle, flaps were transferred to the abdominal region through a subcutaneous tunnel made in the inguinal region. The transfer was performed in the cranial direction as far as possible, avoiding excessive tension on their vascular pedicles. The distance between the most cranial point of the flap (i.e., the tip of the skin paddle) and the umbilicus was defined as cranially reachable distance (CRD). The measured distances were positive when the tips of the skin paddles were extended beyond the umbilicus, and negative when they did not reach the umbilicus. For example, when the tip of the skin paddle reached a point more cranial than the umbilicus by 5 cm, CRD for that flap was evaluated as þ5 cm, but when it fell short of the umbilicus by 2 cm, CRD was evaluated as 2 cm. Hence, CRD is a parameter that indicates how far a flap can reach in the cranial direction. That is, the greater the CRD, the more cranially the flap can be transferred.
Data evaluation The data collected in the above-described measurement system were evaluated to clarify the following three issues. Influence of pedicle positioning on reachable distances In transferring pedicled ALT flaps, the vascular pedicles can be positioned using two approaches. In the first approach, vascular pedicles were positioned superficial to the rectus femoris (RF) and sartorius (SA) muscles (Figure 3A). This method was called superficial positioning. In the second approach, vascular pedicles were placed beneath the two muscles (Figure 4) to avoid hindrance of the pedicles by the two muscles during cranial transfer. This method was called deep positioning (Figure 3B). Each of those 60 flaps was transferred to the abdominal region via any of the two approaches, and CRD was measured for each transfer. Thereafter, the data for the two different approaches were compared.
Rotation arc of pedicled anterolateral thigh flap
1419
Figure 1 A clinical case of abdominal wall reconstruction using an ALT flap. To provide coverage for a defect in the right inferior abdominal region (Left Above), an ALT flap was raised from the right thigh and was transferred to the abdominal region (Right Above and Left Below). Thereby, successful coverage of the defect was achieved (Right Below).
Influence of anatomical variations on reachable distances Vascular pedicles of ALT flaps present two anatomical types. In the first type, the feeding artery of the RF muscle directly branches out from the lateral circumflex femoral artery (Figure 5 Left). This anatomical type is defined as
Type 1. In the second type, the feeding artery of the RF muscle arises more inferiorly from the descending branch of the lateral femoral circumflex artery (Figure 5 Right), and hence creates a pivot point for the pedicle more distally in the thigh. This anatomical type is defined as Type
Figure 2 Design of the flap. The flap was designed on the thigh so that the length of the skin paddle was one-third of the distance between the anterior superior iliac spine and the lateral margin of the patella.
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Figure 3 In transferring the flap to the abdominal region, the vascular pedicle was placed in two ways. (Left) In the first method, the vascular pedicle was positioned on the ventral side of the rectus femoris muscle (R) and sartorius muscle (S). This manner of positioning was named Superficial Positioning. (Right) In the second method, the vascular pedicle was positioned on the dorsal side of the two muscles. This manner of positioning was named Deep Positioning.
2. With reference to these anatomical types, evaluation was conducted with regard to the following issues: Ratios of anatomical types. In order to evaluate occurrence ratios, the number of specimens belonging to each type was counted for the 60 lower limbs. Relationship between anatomical types and CRD. For limbs presenting Type 1 anatomy, a vascular pedicle can be
extended to its maximum length without severing the feeding artery of the RF muscle. ALT flaps raised from these lower limbs were simply transferred to the abdominal region as shown in Figure 6. For lower limbs presenting Type 2 anatomy, transfer of ALT flaps is restricted by the main artery of the RF muscle. This can be eliminated by severing the artery, and further extension can be achieved. On considering this, CRD was measured for lower limbs with Type 2 anatomy under two
Figure 4 In Deep Positioning, the skin paddle and the vascular pedicle were transferred through the space beneath the rectus femoris and sartorius muscles to achieve additional extension in the cranial direction.
Rotation arc of pedicled anterolateral thigh flap
Figure 5 The structure of ALT pedicles is complicated by the existence of two anatomical types. (Left) In Type 1, the feeding artery of the rectus femoris muscle comes from the horizontal branch of the lateral femoral circumflex artery. (Right) In Type 2, the feeding artery of the rectus femoris muscle comes from the descending branch of the lateral circumflex femoral artery.
conditions. In the first condition, which is termed RFbranch preserving condition, the main artery of RF was preserved (Figure 7 Top Right); in the second condition, which was termed RF-branch severing condition, RF’s main artery was severed to achieve additional advancement of the flap (Figure 7 Bottom Right). In order to evaluate the effect of severing RF’s main artery, CRDs were compared between the two conditions. Evaluation of maximum reach of ALT flaps As stated in the previous paragraph, the conditions under which CDRs are maximized differ depending upon the anatomical type of the operated limb. When an ALT flap is raised from a limb with Type 1 anatomy, CRD can be maximized without severing the feeding artery of the RF muscle; when the flap elevation is conducted on a limb with Type 2 anatomy, the feeding artery of the RF muscle needs
1421
Figure 7 In lower limbs with Type 2 anatomy, transfer of the flap is limited by the feeding artery of the rectus femoris muscle, which comes from the descending branch of the lateral circumflex femoral artery. CRD was evaluated in two conditions. In the first condition, the feeding artery was preserved (RF-branch preserving condition); in the second condition, the feeding artery was severed to achieve additional extension of the flap.
to be severed to maximize CRD. After performing appropriate maneuvers according to the anatomical types, CRD was measured for the 60 ALT flaps. Thereafter, the number of flaps that could reach above the umbilicus (i.e., CRD > 0) was determined.
Statistical analyses Comparison of CRD between superior positioning style and deep positioning style was done with a paired t-test. Comparison of CRD between the anatomical types was done with one-way analysis of variance (ANOVA) with post hoc Turkey honestly significance differences (HSD). Stata SE 13.1 (StataCorp LP, College Station, TX, USA) was used for all analyses. p-values
