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Lateral supragenicular pedicle perforator flap: Clinical results and vascular anatomy
Journal of Plastic, Reconstructive & Aesthetic Surgery (2011) 64, 381e385
Lateral supragenicular pedicle perforator flap: Clinical results and vascular anatomy* Alexander T. Nguyen, Corrine Wong, Ali Mojallal, Michel Saint-Cyr* Department of Plastic Surgery, University of Texas Southwestern Medical Centre, 1801 Inwood Road, Dallas TX 75390-9132, USA Received 13 April 2010; accepted 25 May 2010
KEYWORDS Lateral supragenicular artery; Knee reconstruction; Perforator
Summary Background: The lateral supragenicular artery flap has been previously described for soft-tissue reconstruction around the knee. It provides an excellent alternative to muscle and musculocutaneous flaps with less morbidity. The evolution of the understanding of perforator flap anatomy has increased their clinical use and improved flap design. Methods: The authors present a series of cadaveric anatomic studies to further delineate the anatomy of the lateral supragenicular pedicled perforator (LSGAP) flap. The lateral genicular perforator was injected with barium sulphate to locate and map the perforator vascular territories, zones of perfusion and location in relation to standard bony landmarks. Two case presentations exemplify the clinical application of the anatomic findings. Results: Anatomic dissections and selective injection of the genicular perforator found consistent anatomic attributes of pedicle location, axis of flow, linking vessels and vascular territory. LSGAP flaps were used in the case presentations with excellent flap viability and coverage. Conclusions: The LSGAP is another option for soft-tissue coverage around the knee and poplitaeal fossa. The morbidity is minimal as the donor site may frequently be closed primarily without incurring functional impairment. The anatomy of the lateral supragenicular perforator perforasome is reliable and consistent resulting in an additional dependable flap option in our reconstructive armamentarium for coverage of knee and poplitaeal defects. Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons.
* Presented at the American Society of Reconstructive Microsurgery Annual Scientific Meeting, Boca Raton, Florida, January, 2010. * Corresponding author. E-mail address: [email protected] (M. Saint-Cyr).
Soft-tissue reconstruction options around the knee continue to expand. Numerous knee reconstructive variations of flaps have been described, including several muscle, fasciocutaneous and free flaps with the gastrocnemius as the gold standard and workhorse.1e10 Availability of options are particularly important in cases of trauma and amputations where the gastrocnemius may not be available. As the popularity of perforator flaps evolves, the
1748-6815/$ - see front matter Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. doi:10.1016/j.bjps.2010.05.029
382
A.T. Nguyen et al.
evolution of the understanding of perforator flap anatomy has increased their clinical use and improved flap design. The lateral supragenicular artery flap has been previously described for knee coverage in the literature.11e15 In 1989, Laitung found that 86% of posterolateral thigh flaps were supplied by the lateral superior genicular artery.11 In 1990, Hayashi found the superior lateral genicular artery flap to be reliable.12 In line with the evolution of perforator flaps, the authors present a series of cadaveric anatomic studies to further delineate the anatomy of the lateral supragenicular perforator (LSGAP) flap. Two case presentations exemplify the clinical application of the anatomic findings.
Methods and materials Anatomical study An anatomical study was performed on 28 lower limbs from 14 fresh adult cadavers acquired through the Willed Body Program at the University of Texas Southwestern Medical Centre. Specimen dissection was performed under loupe magnification and analysed for locations of the lateral supragenicular artery perforators at the suprafascial level. We recorded the distance of each perforator from the bony landmark of the superolateral patella and its relationship laterally and proximally. The lateral supragenicular perforator zone of perfusion and vascular territory, perforasome, was further delineated by selectively injecting the first perforator. An adipocutaneous flap was harvested off of a lower limb, with the margins being the groin crease, inferior level of the patella and mid-axial anterior and posterior thigh. The lateral supragenicular artery perforator was selectively cannulated with a 24-gauge catheter and injected with a bariumegelatin mixture. The mixture was prepared by warming 100 ml of normal saline to 40 C and adding 3 g of gelatin while stirring continuously. This was followed by slowly adding 40 g of barium sulphate. The flap was then frozen for at least 24 h before being subjected to computed tomography (CT) scanning. Three-dimensional (3-D) images were viewed using the TeraRecon Aquarius workstation (TeraRecon Inc., version 3.2.2.1, San Mateo, CA, USA). This
Figure 1 Cadaveric dissection of a lateral supragenicular perforator.
Figure 2 Location of lateral supragenicular perforators transposed onto a patient’s thigh (x Z horizontal distance and y Z vertical distance from supeo-lateral patella, units in mm).
Figure 3 3D CT angiogram of injected lateral supragenicular perforator adipocutaneous flap, AP view (Margins: groin crease, inferior level of the patella, anterior mid-thigh and posterior mid-thigh).
Lateral supragenicular pedicle perforator flap
383
methodology has been used in previous studies to visualise the perfusion patterns of injected vessels in flaps.16e20
Results Cadaver dissection All 28 lower limbs were found to have between one to three LSGAPs (Figure 1). A total of 53 lateral supragenicular perforators were recorded, averaging 1.89 with a median of two perforators per lower limb. All of the perforators were found within 5 cm laterally and 7 cm proximally from the superolateral patella. The direct distance from this bony landmark averaged 5.3 cm with a median of 5.4 cm (Figure 2).
3-D CT angiography Injection of contrast into an LSGAP onto this total thigh flap revealed its perforasome to be limited to the lower half of the lateral thigh (Figure 3). There was an absence of contrast below the supero-lateral corner of the patella, suggesting that the direction of flow was away from the knee. The sagittal view demonstrated dominant indirect linking vessels, conveying inter-perforator flow in the subdermal plexus. Direct linking vessels were not prominent in this specimen (Figure 4).
Operative technique The lateral supragenicular pedicled perforator flap is designed by identifying an LSGAP with a hand-held Doppler
Figure 4 3D CT angiogram of injected lateral supragenicular perforator adipocutaneous flap, sagittal view.
probe. An axial proximal ellipse is centred over the perforator with up to a 15-cm width that can be closed primarily.21 The flap is elevated without tourniquet in the adipocutaneous plane as the fascia is not necessary to augment the blood supply. It is prudent to preserve superficial veins in the event that the flap needs to be supercharged. The dissection near the perforator may be transitioned to the subfascial plane to protect and help with identification of the perforator. The perforator should not be skeletonised and only dissected enough to allow for the necessary arc of rotation without kinking the vessels. The flap is subsequently inset to the defect and the donor site is primarily closed. The inset must be tension free, and the threshold for skin grafting near the pedicle should be low. The skin graft may be excised during a later revision. It is important to ensure that the Doppler signals, particularly venous, remain the same before and after insetting the flap. Patients who are severely scarred or have very tight skin are generally poor candidates as the pedicle may become impaired.
Figure 5 Case 1 intraoperative photos. (A) 10x12 cm defect with exposed vascular graft. ‘x’ marks lateral supragenicular artery perforator(LSGAP). 10x27 cm flap designed. (B) LSGAP flap elevated and wound debrided. (C) LSGAP (at tip of forceps) (D) Flap inset with primary closure of donor site.
384
A.T. Nguyen et al.
Case 1 A 17-year-old male suffered a gunshot wound to the right knee, transecting the distal poplitaeal artery including the sural vessels. The poplitaeal artery was repaired with an anatomic reversed contralateral saphenous vein graft. Lateral soft-tissue coverage was lost, exposing the vein graft. A LSGAP flap was chosen for coverage of the exposed vasculature. After adequate debridement of the wound was performed, a 10 27-cm flap was designed and inset in a counter-clockwise direction into the defect. The donor site was primarily closed except for a small portion that was skin grafted to minimise tension on the pedicle. The patient healed well with minor delayed tip healing (Figures 5 and 6).
Case 2 A 44-year-old male, who suffered a Gustillo IIIB injury to his right knee 27 years ago with numerous surgical procedures, now needed a total knee replacement; he presented with unstable, thinning skin coverage over the knee. An LSGAP flap was performed to resurface the knee (Figure 7). A 7 28-cm flap was based off of the Doppler signal and inset in a clockwise direction without difficulty. The patient healed well with some delayed tip healing and widening of his donor site scar (Figure 8).
Figure 7 Pre-operative photo of Case 2, showing knee to be covered, and planned LSGAP flap. ＊ marks the Dopplered perforator.
Pedicled perforator flaps offer multiple benefits over alternative flaps. They allow defects to be covered with similar tissue, like with like. Flap dimensions may be customisable to the defect. The complexity and time constraints are minimal compared to more complex flaps. They may be applied to higher risks patients who may not tolerate longer case such as free tissue transfers. With over 350 perforators in the body, reconstructive options are significantly increased.17 The LSGAP flap is another viable option for soft-tissue coverage around the knee and poplitaeal fossa. Alternatives, including the gold standard gastrocnemius muscle, for reconstruction around the knee are limited by short
pedicles, limited volume, poor cosmetic outcomes and variable functional deficits. The LSGAP flap perforator is closer than the distally based anterolateral thigh flap to the knee or poplitaeal region, making it more versatile for coverage of defects of these regions.10 The LSGAP flap offers coverage to typically difficult locations, minimal donor-site morbidity and no functional impairment. The anatomic dissections revealed that the number and location of the lateral supragenicular perforators were reliable and consistent. All perforators mapped within 5 cm and 7 cm laterally and proximally, respectively. The distance from the bony landmark of the supero-lateral patella was predictable at 5.3 cm. This consistent anatomic location correlates to the intermuscular septa between the biceps femoris and vastus lateralis where thigh perforators pierce fascia.22 These findings also correlate well with the location of previous anatomic studies of the perforator’s source vessel, the superior lateral genicular artery.11e13 To truly understand the LSGAP perforasome, the individual perforator must be injected individually.17 To our knowledge, this is the first study to do so on this specific perforator. Injection of contrast found the LSGAP perforasome to be limited to the lower half of the thigh
Figure 6 Case 1 at two months post-operative, flap and donor site healed.
Figure 8 Case 2 at ten months post-operative, flap and donor site healed.
Discussion
Lateral supragenicular pedicle perforator flap (Figure 3), defining the limits of the length of the flap. The width is only limited by the ability to primarily close the donor defect. The absence of contrast below the superolateral patella suggests that the direction of flow is away from the knee. This supports the perforasome theory, whereby the principles state that perfusion travels axially away from a joint in extremities.17 The dominant indirect linking vessels, conveying inter-perforator flow in the subdermal plexus and lack of direct linking vessels, confirm our findings of limited, averaging 1.89, major perforators in this region. This also supports raising adipofascial flaps because the dominant linking vessels are not in the suprafascial plane. The LSGAP perforasome, with limited perforators, correlates well with the angiosome of the poplitaeal source vessel as described by Pan and Taylor.22 The LSGAP flap is another option for soft-tissue coverage around the knee and poplitaeal fossa. The morbidity is minimal as the donor site may frequently be closed primarily without incurring functional impairment. This study further delineates the LSGAP flap anatomy to improve its use and design which may be used for the medial perforators as well. The anatomy of the lateral supragenicular perforator perforasome is reliable and consistent resulting in an additional dependable flap option in our reconstructive armamentarium for the coverage of knee and poplitaeal defects.
Conflict of interest None.
Financial disclosures The authors have no financial interests with regard to the contents of this article.
References 1. Elsahy NI. Cover of the exposed knee joint by the lateral head of the gastrocnemius. Br J Plast Surg 1978;31:136e7. 2. Feldman JJ, Cohen BE, May Jr JW. The medial gastrocnemius myocutaneous flap. Plast Reconstr Surg 1978;61:531e9. 3. Swartz WM, Ramasastry SS, McGill JR, et al. Distally based vastus lateralis muscle flap for coverage of wounds about the knee. Plast Reconstr Surg 1987;80:255e65. 4. Petty CT, Hogue Jr RJ. Closure of an exposed knee joint by use of a sartorius muscle flap: case report. Plast Reconstr Surg 1978;62:458e61.
385 5. Ponten B. The fasciocutaneous flap: its use in soft tissue defects of the lower leg. Br J Plast Surg 1981;34:215e20. 6. Lin SD, Lai CS, Chiu YT, et al. Adipofascial flap of the lower leg based on the saphenous artery. Br J Plast Surg 1996;49:390e5. 7. Kasabian AK, Colen SR, Shaw WW, et al. The role of microvascular free flaps in salvaging below-knee amputation stumps: a review of 22 cases. J Trauma 1991;31:495e500. discussion 500e491. 8. McCraw JB, Fishman JH, Sharzer LA. The versatile gastrocnemius myocutaneous flap. Plast Reconstr Surg 1978;62:15e23. 9. Nahabedian MY, Mont MA, Orlando JC, et al. Operative management and outcome of complex wounds following total knee arthroplasty. Plast Reconstr Surg 1999;104:1688e97. 10. Zhang G. Reversed anterolateral thigh island flap and myocutaneous flap transplantation. Zhonghua Yi Xue Za Zhi 1990;70: 676e8. 646. 11. Laitung JK. The lower posterolateral thigh flap. Br J Plast Surg 1989;42:133e9. 12. Hayashi A, Maruyama Y. The lateral genicular artery flap. Ann Plast Surg 1990;24:310e7. 13. Spokevicius S, Jankauskas A. Anatomy and clinical applications of a composite cutaneo-subcutaneous flap based on the lateral superior genicular vessels. J Reconstr Microsurg 1995;11: 15e20. 14. Li X, Huang S, Su J, et al. Investigation of a retrograded supragenicular flap for treatment of scarring contraction of popiteal fossa. Zhonghua Zheng Xing Wai Ke Za Zhi 2002;18:343e5. 15. Taniguchi Y, Kitano T, Shimoe T, et al. Superior lateral genicular artery flap for coverage of a soft tissue defect after total knee arthroplasty. J Reconstr Microsurg 2009;25:479e82. 16. Saint-Cyr M, Schaverien M, Arbique G, et al. Three- and fourdimensional computed tomographic angiography and venography for the investigation of the vascular anatomy and perfusion of perforator flaps. Plast Reconstr Surg 2008;121: 772e80. 17. Saint-Cyr M, Wong C, Schaverien M, et al. Perforasome theory: vascular anatomy and clinical implications. Plast Reconstr Surg 2009;124:1529. 18. Wong C, Saint-Cyr M, Arbique G, et al. Three- and fourdimensional computed tomography angiographic studies of commonly used abdominal flaps in breast reconstruction. Plast Reconstr Surg 2009;124:18e27. 19. Wong C, Saint-Cyr M, Rasko Y, et al. Three- and four-dimensional arterial and venous perforasomes of the internal mammary artery perforator flap. Plast Reconstr Surg 2009; 124:1759e69. 20. Tan BK, Ng RT, Tay NS, et al. Tissue microangiography using a simplified barium sulphate cadaver injection technique. Ann Acad Med Singapore 1999;28:152e4. 21. Saint-Cyr M, Schaverien M, Wong C, et al. The extended anterolateral thigh flap: anatomical basis and clinical experience. Plast Reconstr Surg 2009;123:1245e55. 22. Pan WR, Taylor GI. The angiosomes of the thigh and buttock. Plast Reconstr Surg 2009;123:236e49.
Lateral supragenicular pedicle perforator flap: Clinical results and vascular anatomy* Alexander T. Nguyen, Corrine Wong, Ali Mojallal, Michel Saint-Cyr* Department of Plastic Surgery, University of Texas Southwestern Medical Centre, 1801 Inwood Road, Dallas TX 75390-9132, USA Received 13 April 2010; accepted 25 May 2010
KEYWORDS Lateral supragenicular artery; Knee reconstruction; Perforator
Summary Background: The lateral supragenicular artery flap has been previously described for soft-tissue reconstruction around the knee. It provides an excellent alternative to muscle and musculocutaneous flaps with less morbidity. The evolution of the understanding of perforator flap anatomy has increased their clinical use and improved flap design. Methods: The authors present a series of cadaveric anatomic studies to further delineate the anatomy of the lateral supragenicular pedicled perforator (LSGAP) flap. The lateral genicular perforator was injected with barium sulphate to locate and map the perforator vascular territories, zones of perfusion and location in relation to standard bony landmarks. Two case presentations exemplify the clinical application of the anatomic findings. Results: Anatomic dissections and selective injection of the genicular perforator found consistent anatomic attributes of pedicle location, axis of flow, linking vessels and vascular territory. LSGAP flaps were used in the case presentations with excellent flap viability and coverage. Conclusions: The LSGAP is another option for soft-tissue coverage around the knee and poplitaeal fossa. The morbidity is minimal as the donor site may frequently be closed primarily without incurring functional impairment. The anatomy of the lateral supragenicular perforator perforasome is reliable and consistent resulting in an additional dependable flap option in our reconstructive armamentarium for coverage of knee and poplitaeal defects. Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons.
* Presented at the American Society of Reconstructive Microsurgery Annual Scientific Meeting, Boca Raton, Florida, January, 2010. * Corresponding author. E-mail address: [email protected] (M. Saint-Cyr).
Soft-tissue reconstruction options around the knee continue to expand. Numerous knee reconstructive variations of flaps have been described, including several muscle, fasciocutaneous and free flaps with the gastrocnemius as the gold standard and workhorse.1e10 Availability of options are particularly important in cases of trauma and amputations where the gastrocnemius may not be available. As the popularity of perforator flaps evolves, the
1748-6815/$ - see front matter Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. doi:10.1016/j.bjps.2010.05.029
382
A.T. Nguyen et al.
evolution of the understanding of perforator flap anatomy has increased their clinical use and improved flap design. The lateral supragenicular artery flap has been previously described for knee coverage in the literature.11e15 In 1989, Laitung found that 86% of posterolateral thigh flaps were supplied by the lateral superior genicular artery.11 In 1990, Hayashi found the superior lateral genicular artery flap to be reliable.12 In line with the evolution of perforator flaps, the authors present a series of cadaveric anatomic studies to further delineate the anatomy of the lateral supragenicular perforator (LSGAP) flap. Two case presentations exemplify the clinical application of the anatomic findings.
Methods and materials Anatomical study An anatomical study was performed on 28 lower limbs from 14 fresh adult cadavers acquired through the Willed Body Program at the University of Texas Southwestern Medical Centre. Specimen dissection was performed under loupe magnification and analysed for locations of the lateral supragenicular artery perforators at the suprafascial level. We recorded the distance of each perforator from the bony landmark of the superolateral patella and its relationship laterally and proximally. The lateral supragenicular perforator zone of perfusion and vascular territory, perforasome, was further delineated by selectively injecting the first perforator. An adipocutaneous flap was harvested off of a lower limb, with the margins being the groin crease, inferior level of the patella and mid-axial anterior and posterior thigh. The lateral supragenicular artery perforator was selectively cannulated with a 24-gauge catheter and injected with a bariumegelatin mixture. The mixture was prepared by warming 100 ml of normal saline to 40 C and adding 3 g of gelatin while stirring continuously. This was followed by slowly adding 40 g of barium sulphate. The flap was then frozen for at least 24 h before being subjected to computed tomography (CT) scanning. Three-dimensional (3-D) images were viewed using the TeraRecon Aquarius workstation (TeraRecon Inc., version 3.2.2.1, San Mateo, CA, USA). This
Figure 1 Cadaveric dissection of a lateral supragenicular perforator.
Figure 2 Location of lateral supragenicular perforators transposed onto a patient’s thigh (x Z horizontal distance and y Z vertical distance from supeo-lateral patella, units in mm).
Figure 3 3D CT angiogram of injected lateral supragenicular perforator adipocutaneous flap, AP view (Margins: groin crease, inferior level of the patella, anterior mid-thigh and posterior mid-thigh).
Lateral supragenicular pedicle perforator flap
383
methodology has been used in previous studies to visualise the perfusion patterns of injected vessels in flaps.16e20
Results Cadaver dissection All 28 lower limbs were found to have between one to three LSGAPs (Figure 1). A total of 53 lateral supragenicular perforators were recorded, averaging 1.89 with a median of two perforators per lower limb. All of the perforators were found within 5 cm laterally and 7 cm proximally from the superolateral patella. The direct distance from this bony landmark averaged 5.3 cm with a median of 5.4 cm (Figure 2).
3-D CT angiography Injection of contrast into an LSGAP onto this total thigh flap revealed its perforasome to be limited to the lower half of the lateral thigh (Figure 3). There was an absence of contrast below the supero-lateral corner of the patella, suggesting that the direction of flow was away from the knee. The sagittal view demonstrated dominant indirect linking vessels, conveying inter-perforator flow in the subdermal plexus. Direct linking vessels were not prominent in this specimen (Figure 4).
Operative technique The lateral supragenicular pedicled perforator flap is designed by identifying an LSGAP with a hand-held Doppler
Figure 4 3D CT angiogram of injected lateral supragenicular perforator adipocutaneous flap, sagittal view.
probe. An axial proximal ellipse is centred over the perforator with up to a 15-cm width that can be closed primarily.21 The flap is elevated without tourniquet in the adipocutaneous plane as the fascia is not necessary to augment the blood supply. It is prudent to preserve superficial veins in the event that the flap needs to be supercharged. The dissection near the perforator may be transitioned to the subfascial plane to protect and help with identification of the perforator. The perforator should not be skeletonised and only dissected enough to allow for the necessary arc of rotation without kinking the vessels. The flap is subsequently inset to the defect and the donor site is primarily closed. The inset must be tension free, and the threshold for skin grafting near the pedicle should be low. The skin graft may be excised during a later revision. It is important to ensure that the Doppler signals, particularly venous, remain the same before and after insetting the flap. Patients who are severely scarred or have very tight skin are generally poor candidates as the pedicle may become impaired.
Figure 5 Case 1 intraoperative photos. (A) 10x12 cm defect with exposed vascular graft. ‘x’ marks lateral supragenicular artery perforator(LSGAP). 10x27 cm flap designed. (B) LSGAP flap elevated and wound debrided. (C) LSGAP (at tip of forceps) (D) Flap inset with primary closure of donor site.
384
A.T. Nguyen et al.
Case 1 A 17-year-old male suffered a gunshot wound to the right knee, transecting the distal poplitaeal artery including the sural vessels. The poplitaeal artery was repaired with an anatomic reversed contralateral saphenous vein graft. Lateral soft-tissue coverage was lost, exposing the vein graft. A LSGAP flap was chosen for coverage of the exposed vasculature. After adequate debridement of the wound was performed, a 10 27-cm flap was designed and inset in a counter-clockwise direction into the defect. The donor site was primarily closed except for a small portion that was skin grafted to minimise tension on the pedicle. The patient healed well with minor delayed tip healing (Figures 5 and 6).
Case 2 A 44-year-old male, who suffered a Gustillo IIIB injury to his right knee 27 years ago with numerous surgical procedures, now needed a total knee replacement; he presented with unstable, thinning skin coverage over the knee. An LSGAP flap was performed to resurface the knee (Figure 7). A 7 28-cm flap was based off of the Doppler signal and inset in a clockwise direction without difficulty. The patient healed well with some delayed tip healing and widening of his donor site scar (Figure 8).
Figure 7 Pre-operative photo of Case 2, showing knee to be covered, and planned LSGAP flap. ＊ marks the Dopplered perforator.
Pedicled perforator flaps offer multiple benefits over alternative flaps. They allow defects to be covered with similar tissue, like with like. Flap dimensions may be customisable to the defect. The complexity and time constraints are minimal compared to more complex flaps. They may be applied to higher risks patients who may not tolerate longer case such as free tissue transfers. With over 350 perforators in the body, reconstructive options are significantly increased.17 The LSGAP flap is another viable option for soft-tissue coverage around the knee and poplitaeal fossa. Alternatives, including the gold standard gastrocnemius muscle, for reconstruction around the knee are limited by short
pedicles, limited volume, poor cosmetic outcomes and variable functional deficits. The LSGAP flap perforator is closer than the distally based anterolateral thigh flap to the knee or poplitaeal region, making it more versatile for coverage of defects of these regions.10 The LSGAP flap offers coverage to typically difficult locations, minimal donor-site morbidity and no functional impairment. The anatomic dissections revealed that the number and location of the lateral supragenicular perforators were reliable and consistent. All perforators mapped within 5 cm and 7 cm laterally and proximally, respectively. The distance from the bony landmark of the supero-lateral patella was predictable at 5.3 cm. This consistent anatomic location correlates to the intermuscular septa between the biceps femoris and vastus lateralis where thigh perforators pierce fascia.22 These findings also correlate well with the location of previous anatomic studies of the perforator’s source vessel, the superior lateral genicular artery.11e13 To truly understand the LSGAP perforasome, the individual perforator must be injected individually.17 To our knowledge, this is the first study to do so on this specific perforator. Injection of contrast found the LSGAP perforasome to be limited to the lower half of the thigh
Figure 6 Case 1 at two months post-operative, flap and donor site healed.
Figure 8 Case 2 at ten months post-operative, flap and donor site healed.
Discussion
Lateral supragenicular pedicle perforator flap (Figure 3), defining the limits of the length of the flap. The width is only limited by the ability to primarily close the donor defect. The absence of contrast below the superolateral patella suggests that the direction of flow is away from the knee. This supports the perforasome theory, whereby the principles state that perfusion travels axially away from a joint in extremities.17 The dominant indirect linking vessels, conveying inter-perforator flow in the subdermal plexus and lack of direct linking vessels, confirm our findings of limited, averaging 1.89, major perforators in this region. This also supports raising adipofascial flaps because the dominant linking vessels are not in the suprafascial plane. The LSGAP perforasome, with limited perforators, correlates well with the angiosome of the poplitaeal source vessel as described by Pan and Taylor.22 The LSGAP flap is another option for soft-tissue coverage around the knee and poplitaeal fossa. The morbidity is minimal as the donor site may frequently be closed primarily without incurring functional impairment. This study further delineates the LSGAP flap anatomy to improve its use and design which may be used for the medial perforators as well. The anatomy of the lateral supragenicular perforator perforasome is reliable and consistent resulting in an additional dependable flap option in our reconstructive armamentarium for the coverage of knee and poplitaeal defects.
Conflict of interest None.
Financial disclosures The authors have no financial interests with regard to the contents of this article.
References 1. Elsahy NI. Cover of the exposed knee joint by the lateral head of the gastrocnemius. Br J Plast Surg 1978;31:136e7. 2. Feldman JJ, Cohen BE, May Jr JW. The medial gastrocnemius myocutaneous flap. Plast Reconstr Surg 1978;61:531e9. 3. Swartz WM, Ramasastry SS, McGill JR, et al. Distally based vastus lateralis muscle flap for coverage of wounds about the knee. Plast Reconstr Surg 1987;80:255e65. 4. Petty CT, Hogue Jr RJ. Closure of an exposed knee joint by use of a sartorius muscle flap: case report. Plast Reconstr Surg 1978;62:458e61.
385 5. Ponten B. The fasciocutaneous flap: its use in soft tissue defects of the lower leg. Br J Plast Surg 1981;34:215e20. 6. Lin SD, Lai CS, Chiu YT, et al. Adipofascial flap of the lower leg based on the saphenous artery. Br J Plast Surg 1996;49:390e5. 7. Kasabian AK, Colen SR, Shaw WW, et al. The role of microvascular free flaps in salvaging below-knee amputation stumps: a review of 22 cases. J Trauma 1991;31:495e500. discussion 500e491. 8. McCraw JB, Fishman JH, Sharzer LA. The versatile gastrocnemius myocutaneous flap. Plast Reconstr Surg 1978;62:15e23. 9. Nahabedian MY, Mont MA, Orlando JC, et al. Operative management and outcome of complex wounds following total knee arthroplasty. Plast Reconstr Surg 1999;104:1688e97. 10. Zhang G. Reversed anterolateral thigh island flap and myocutaneous flap transplantation. Zhonghua Yi Xue Za Zhi 1990;70: 676e8. 646. 11. Laitung JK. The lower posterolateral thigh flap. Br J Plast Surg 1989;42:133e9. 12. Hayashi A, Maruyama Y. The lateral genicular artery flap. Ann Plast Surg 1990;24:310e7. 13. Spokevicius S, Jankauskas A. Anatomy and clinical applications of a composite cutaneo-subcutaneous flap based on the lateral superior genicular vessels. J Reconstr Microsurg 1995;11: 15e20. 14. Li X, Huang S, Su J, et al. Investigation of a retrograded supragenicular flap for treatment of scarring contraction of popiteal fossa. Zhonghua Zheng Xing Wai Ke Za Zhi 2002;18:343e5. 15. Taniguchi Y, Kitano T, Shimoe T, et al. Superior lateral genicular artery flap for coverage of a soft tissue defect after total knee arthroplasty. J Reconstr Microsurg 2009;25:479e82. 16. Saint-Cyr M, Schaverien M, Arbique G, et al. Three- and fourdimensional computed tomographic angiography and venography for the investigation of the vascular anatomy and perfusion of perforator flaps. Plast Reconstr Surg 2008;121: 772e80. 17. Saint-Cyr M, Wong C, Schaverien M, et al. Perforasome theory: vascular anatomy and clinical implications. Plast Reconstr Surg 2009;124:1529. 18. Wong C, Saint-Cyr M, Arbique G, et al. Three- and fourdimensional computed tomography angiographic studies of commonly used abdominal flaps in breast reconstruction. Plast Reconstr Surg 2009;124:18e27. 19. Wong C, Saint-Cyr M, Rasko Y, et al. Three- and four-dimensional arterial and venous perforasomes of the internal mammary artery perforator flap. Plast Reconstr Surg 2009; 124:1759e69. 20. Tan BK, Ng RT, Tay NS, et al. Tissue microangiography using a simplified barium sulphate cadaver injection technique. Ann Acad Med Singapore 1999;28:152e4. 21. Saint-Cyr M, Schaverien M, Wong C, et al. The extended anterolateral thigh flap: anatomical basis and clinical experience. Plast Reconstr Surg 2009;123:1245e55. 22. Pan WR, Taylor GI. The angiosomes of the thigh and buttock. Plast Reconstr Surg 2009;123:236e49.