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Covering small defects on the weight bearing surfaces of the foot: the free temporal fasciocutaneous flap
British Journal of Plastic Surgery (2005) 58, 460–465
Covering small defects on the weight bearing surfaces of the foot: the free temporal fasciocutaneous flapq O. Heymans*, N. Verhelle, T. Lahaye `ge, Bat. B 35, Lie `ge BDepartment of Plastic and Reconstructive Surgery, CHU Sart Tilman, University of Lie 4000, Belgium Received 8 August 2003; accepted 23 December 2003
KEYWORDS Small defects; Weight bearing area of the heel; Shearing strains; Free fasciocutaneous temporal flap
Summary Although defects in the weight bearing area of the heel can be covered by local flaps, radiodermatitis is a contraindication to these flaps. Thin free flaps, as grafted fascial or muscles flaps and thin fasciocutaneous flaps, are usually the option of choice in these particular defects. These reconstructions are prone to shearing strains resulting in ulceration, hypertrophic scars and hyperkeratosis. The authors present a retrospective study of the reconstruction of six small heel defects with the fasciocutaneous temporal free flap performed between 1996 and 2001. The mean size of the defect was 20 cm2. All arterial anastomoses were performed end to side on the posterior tibial artery. Despite the flap thinness, swelling was present during 12 –25 months and one debulking had to be performed. With a mean follow-up of 32 months, all flaps regained protective sensibility after 7 months. No sliding of the flaps could be noted but there was one transient hyperkeratosis. Although the amount of hair on the transferred flaps decreased spontaneously with time, laser hair removal was performed in two patients for psychological reasons. In conclusion, it seems that in selected cases where local flaps are contraindicated, the fasciocutaneous temporal free flap can offer an excellent alternative for heel reconstruction. Due to its particular architecture, it resembles the complex tissue of the sole of the foot resulting in fewer complications and maintenance of flap durability. Q 2004 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved.
Reconstruction of soft tissue defects of the weight bearing surface of the foot is difficult. Although conventional local flaps can be used for the coverq Presented at the second meeting of the World Society of Reconstructive Microsurgery, June 2003 (Heidelberg, Germany). *Corresponding author. Address: Department of Plastic and Maxillo-Facial Surgery, CHU Sart Tilman, University of Lie `ge, Bat. B 35, Lie `ge B-4000, Belgium. Tel.: þ32-4-366-72-12; fax: þ 32-4366-70-61. E-mail address: [email protected]
age of small defects, extensive and more complex defects can only be treated by microsurgical flap transfer. Whatever flap is chosen, it is almost impossible to replace the functional complexity of the weight bearing area of the foot. Transferred tissues have to resist the shearing forces in order to prevent complications as ulcerations, hypertrophic scar formation and hyperkeratosis. The skin on the plantar area of the foot is the thickest in the body and is supported by dense subcutaneous tissue with
S0007-1226/$ - see front matter Q 2004 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2003.12.038
Covering small defects on the weight bearing surfaces of the foot
vertically oriented fibrous septae that anchor the plantar skin to the underlying fascia. In order to replace the soft tissue defect on the weight bearing area of the heel with an optimal free transferred substitute, we performed six free fasciocutaneous temporal flaps after debridement of plantar radiodermitis wounds. The subcutis of the scalp is traversed by dense connective tissue, binding the thick skin to the underlying fascia. In this respect, its complex architecture is histologicaly comparable with the heel structure (Fig. 1). The purpose of this small study was to review our experience with these fasciocutaneous temporal flaps for small defects on the weight bearing area of the heel.
Material and methods Between 1996 and 2001, we performed six heel reconstructions with a fasciocutaneous temporalis free flap in the weight-bearing area of the foot. Five women and one man, ranging in age from 27 to 52 years (mean 40.2) have been included in this study. They all presented with chronic wounds secondary to radiation therapy for recurrent warts (five) or Lederhose disease (one). No patient had osteomyelitis and all had clinically normal vasculature. The size of defects varied from 15 to 30 cm2 (mean 20 cm2). In all patients, the fasciocutaneous temporal flap was harvested in the classical way and one extra centimeter of fascia, surrounding the skin paddle was included in the flap. All donor sites were
461
closed primarily. All microsurgical arterial anastomoses were performed end to side on the posterior tibial artery while the venous anastomoses were performed end to end to one of the concomitant veins of the posterior tibial artery. In none of the flaps was the auriculo-temporal nerve harvested. The fascia, surrounding the skin paddle by 1 cm, was strongly attached to the periosteum around the defect in order to prevent sliding of the fascia on the bone.
Results The fasciocutaneous temporal flap was successful in all six cases with no flap necrosis. Revision of a venous anastomosis had to be performed in one case. During follow-up (mean 32 months), a persistent swelling of these thin flaps was obvious for 12 –25 months. In one patient, flap debulking had to be performed 20 months after transfer because the bulkiness had caused an ulceration of the flap. After debulking, the ulcer healed uneventful. We also noted one transient hyperkeratosis, but all other scars healed well without hypertrophy. Every transferred flap presented with hair growth without functional disability. However, the amount of hair decreased spontaneously with time, and laser hair removal was only performed for psychological reasons in two patients (Fig. 2). The assessment of gait was based on the authors’ subjective observation as the patient walked without footwear, and five patients regained a normal gait pattern postoperatively and could wear normal footwear of their usual size. Only one patient (who needed the flap debulking) had a slightly altered gait pattern and required larger footwear with silicone inlay. All patients had protective sensation after 7 months although no nerve coaptation had been performed peroperatively. The donor sites healed well although one patient suffered from transient alopecia and one patient presented with a widened scar after 6 months. However, no patient had to change his or her hairstyle. Due to the large undermining, essential to perform direct closure, all patients suffered from transient hypoesthesia during 5 months.
Discussion Figure 1 Comparable histological sections with the fibrous septae in the heel (arrows, A) and the dense connective tissue between the skin and the underlying fascia in the scalp (arrows, B).
Although defects of the weight bearing area of the heel can be covered by different local flaps such as the medial plantar flap, we regard radiodermatitis as a relative contraindication. In radiodermatitis
462
O. Heymans et al.
Figure 2 Clinical results. (A) Peroperative result. (B) Postoperative result after 3 months with apparent hair growth. (C) Result after 6 months with clearly less hair growth. (D) Result 1 year postoperatively after laser hair removal.
wounds, the defect is usually limited to the soft tissues, sparing the bony structure. The ideal free flap for reconstruction of the foot should be thin, so grafted fascial free flaps such as the serratus fascial flap, the temporal fascial flap or the radial forearm fascial flap, are usually preferred over bulky muscle flaps1,2 in smaller defects. However, due to its unique architectural characteristics, the heel skin is normally able to withstand pressure and shearing strains, preventing the complications which are often encountered after these free fascial flap procedures to the weight bearing area of the heel. The thick plantar skin and the underlying elastic adipose tissue allow the dispersion of vertical and horizontal shearing forces that accompany walking.3 Once reconstructed with other soft tissues, this specific dispersion is lost resulting in sliding of the foot on the flap during walking (Fig. 3). Unlike the neighbouring skin, the flap surface is not strongly attached to the calcaneum by fibrous septas. Free muscle flaps with skin grafts develop two independent mobile tissue planes: one at the muscle to the underlying tissue interface and a second at the skin graft to muscle free flap interface (Fig. 4(A)). Free fascial flaps can be strongly attached to the periosteum and sutured with tension over the calcaneum diminishing the sliding of the flap. These flaps, however, also have to be skin grafted so a mobile tissue plan still
persists at the skin graft to free flap interface. There is, however, a minimal mobile tissue plan between the fascia and underlying bone resulting in better resistance to shearing strains. In free fasciocutaneous flaps as the radial forearm flap, the same problem is encountered, even more obviously (Fig. 4(B)). The subcutaneous tissue represents a mobile tissue plane between the fascia, which can be strongly attached to the periosteum, and the skin. The sliding of the skin over the fascia is even more important than in grafted fascial flaps because of the subcutaneous layer, which is absent in grafted flaps. The architecture of a free cutaneous flap resembles more the subcutaneous elastic adipose architecture of the plantar surface, but they are often too bulky and they are difficult to attach to the underlying bone. The contralateral free medial plantar flap may represent the best solution because of the identical tissue characteristics. However, this flap has significant donor site considerations and entails that the noninjured foot will also have scars postoperatively. Although it has been suggested that free cutaneous flaps intrinsically resist shear forces4,5 and that different mobile planes allow resistance to tangential shear forces,6,7 we are convinced that the sliding of tissues plays an important role in the development of postoperative ulcerations,
Covering small defects on the weight bearing surfaces of the foot
463
Figure 3 Clinical effect of the shearing strains and the resulting sliding of a radial forearm flap after transfer to a heel defect. (A) Without shearing strains. (B) During shearing strains.
Figure 4 Schematic drawings after free tissue transfer. (A) Free muscle grafted with two sliding planes; one between the muscle and the bone, a second between the muscle and skin graft. (B) Free fasciocutaneous flap with the fascia strongly attached to the periostium leaving only one sliding plane. (C) The apparent connections of fibrotic tissue between the skin and underlying fascia in the scalp. (D) Free fasciocutaneous temporal flap with maximal resistance to shearing strains.
464
hyperkeratosis and hypertrophic scar formation. Grafted fascial free flaps are preferable over other flaps1,2,8 because of fewer postoperative complications. It is our opinion that this may be explained by the fact that these flaps can attach more strongly to the underlying bone and presents the less mobile tissue plans as mentioned above. In our search for the most similar substitute for the ‘irreplaceable’ heel skin, we performed histological sections of the scalp (Fig. 1). It is known that the subcutaneous layer of the scalp is transversed by dense connective tissue, binding the hair bearing scalp to the underlying fascia.9 This flap has already been used for a wide variety of reconstructive procedures and it has proven its reliability.10 – 12 In our opinion, this scalp tissue most resembles the heel tissue, and we think that the natural attachment of the temporo-parietal skin to the fascia is able to withstand the shearing strains and that these septae act as a shock absorbing system as do the fibrous septae in normal heel skin (Fig. 4(C) and (D)). In our small series, we were able to attach the temporal fascia strongly to the periosteum and thus preventing the first sliding plane as in the free fascial flaps. Thanks to the fibrous septa in the subcutaneous tissue, which are strongly adherent to the fascia, the second sliding plane is also reduced to a minimum. Resistance to the shearing forces is maximum leading to fewer postoperative complications as seen in our small series. Nevertheless, complications can occur since flaps on weight-bearing surfaces of the foot are more prone to ulcers than those on nonbearing surfaces. These ulcers seem to be independent of flap origin, flap sensibility and the cause of the primary defect.13 They are however, mechanical in origin and arise from exogenous and endogenous causes. The exogenous ulcers appear mostly on free flaps that are unusually thick and conform poorly to the osseous architecture of the foot. This may explain why we had the ulceration in the thick flap that healed uneventfully after flap debulking confirming our opinion that exogenous ulcers can be prevented by applying this thin fasciocutaneous flap. Ulcers from endogenous origin develop exclusively in conjunction with weight-bearing points and pressure sites overlying osseous deformities. These high pressure points are the most important reason for recurrent breakdowns, and can be prevented by paying attention to the normal skeletal architectural features of the foot during reconstruction.13,14 Not only resection of bony spurs, but also appropriate orthopaedic procedures should be performed and supportive footwear should be provided to obtain a better gait and prevent recurrent ulceration.15 Another important
O. Heymans et al.
issue is the tendency of larger defects to exhibit these ulcerations more frequently. Since our series deals with only small defects, we will not include this issue in our discussion. Discussion still exists as to whether sensory nerve coaptation should be performed or not. Even with noninnervated flaps, protective sensibility can be achieved after 1 year by most patients. Many authors advocate that the most important factor for the maintenance of flap durability is the presence of deep pressure sensation.15 Santanelli et al.8 concluded in their study that nerve coaptation should be used in young, healthy motivated patients to improve stability of the flap with an earlier return to load capacity and a full recovery to normal activity. Once again, their study included large defects and we think that it cannot be compared with the faster sensory recovery in small flaps as in our series. Whenever plantar reconstructions are performed, hypertrophic scars and hyperkeratosis may develop. These pathologic events seem to be provoked by shearing forces in somewhat bulky flaps, and can be solved by flap thinning and tightening in combination with scar revision and Z plasties.16,17 By transferring the fasciocutaneous temporal flap and thus, as mentioned above, diminishing the shearing strains, we only noticed one transient hypertrophic scar. The donor site morbidity, similar to a classical fascial temporal flap, consists mainly of alopecia in the immediate vicinity of the incisions. This however, may be transient and can be avoided by meticulous dissection. Another disadvantage is the transient hypoesthesia (5 months) of the undermined area, mandatory to obtain primary closure. Transferring hair-bearing skin to the plantar area may constitute some psychological problems for the patient, but had no functional repercussion. As time passed by, the number of hairs reduced significantly. Nevertheless, in two patients the remaining hairs were removed by laser techniques (ruby laser). The fasciocutaneous temporal free flap can provide a reliable wound coverage option in selected cases. We successfully used this flap in small defects on the weight-bearing area of irradiated heels where local flaps are contraindicated. Due to its specific anatomical structure, a natural contour could be restored that could withstand pressure and shearing strains. In this way, we think that the postoperative complications could be diminished with minimal donor site morbidity, although larger series with a longer follow-up have to be performed to confirm our findings.
Covering small defects on the weight bearing surfaces of the foot
References 1. Woods JM, Shack RB, Hagan KF. Free temporoparietal fascia flap in reconstruction of the lower extremity. Ann Plast Surg 1995;34:501—6. 2. Rainer C, Schwabegger AH, Bauer T, et al. Free flap reconstruction of the foot. Ann Plast Surg 1999;42:595—607. 3. May Jr JW, Rohrich RJ. Foot reconstruction using free microvascular free flaps with skin grafts. Clin Plast Surg 1986;13:681—9. 4. Russell RC, Guy RJ, Zook EG, Merrell JC. Extremity reconstruction using the free deltoid flap. Plast Reconstr Surg 1985;76:586—95. 5. Duncan MJ, Zucker RM, Mankletow RT. Resurfacing weightbearing areas of the heel: the role of the dorsalis pedis innervated free transfer. J Reconstr Microsurg 1985;1: 201—8. 6. Goldberg JA, Adkins P, Tsai TM. Microvascular reconstruction of the foot: weight-bearing patterns, gait analysis, and long term follow-up. Plast Reconstr Surg 1993;92:904—11. 7. May Jr JW, Halls MJ, Simon SR. Free microvascular muscle flaps with skin graft reconstruction of extensive defects of the foot: a clinical and gait analysis study. Plast Reconstr Surg 1985;75:627—41. 8. Santanelli F, Tenna S, Pace A, Scuderi N. Free flap reconstruction of the sole f the foot with or without sensory nerve coaptation. Plast Reconstr Surg 2002;109:2314—22. 9. Smith RA. The free fascial scalp flap. Plast Reconstr Surg 1980;66:204—9.
465
10. Chang KP, Lai CS, Tsai CC, Lin TM, Lin SD. Total upper lip reconstruction with a free temporal scalp flap: long term follow up. Head Neck 2003;25:602—5. 11. Tanaka A, Hatoko M, Shiba A, et al. An experience of pubic hair reconstruction using free temporoparietal fasciocutaneous flap with needle epilation. Plast Reconstr Surg 1999; 104:187—9. 12. David JM, Paoli JR, Bejjani W, Bonnet F, Bachaud JM, Barthelemy I. Le lambeau fascio-cutane temporal en ilot dans la reconstruction muqueuse de l’oropharynx et de la cavite buccale apre `s exerese carcinologique. Rev Stomatol Chir maxillofac 1994;95:313—8. 13. Sonmez A, Bayramicli M, Sonmez B, Numanoglu A. Reconstruction of the weight-bearing surface of the foot with nonneurosensory free flaps. Plast Reconstr Surg 2003;111: 2230—6. 14. Milanov NO, Adamyan RT. Functional results of microsurgical reconstruction of plantar defects. Ann Plast Surg 1994;32: 52—6. 15. Yucel A, Senyuva C, Aydin Y, Cinar C, Guzel Z. Soft-tissue reconstruction of sole and heel defects with free tissue transfers. Ann Plast Surg 2000;44:259—69. 16. Reigstad A, Hetland KR, Byet K, et al. Free flaps in the reconstruction of foot injury. Acta Orthop Scand 1994;65: 103—6. 17. Noever G, Bruser P, Kohler L. Reconstruction of heel and sole defects by free flaps. Plast Reconstr Surg 1986;78:345—52.
Covering small defects on the weight bearing surfaces of the foot: the free temporal fasciocutaneous flapq O. Heymans*, N. Verhelle, T. Lahaye `ge, Bat. B 35, Lie `ge BDepartment of Plastic and Reconstructive Surgery, CHU Sart Tilman, University of Lie 4000, Belgium Received 8 August 2003; accepted 23 December 2003
KEYWORDS Small defects; Weight bearing area of the heel; Shearing strains; Free fasciocutaneous temporal flap
Summary Although defects in the weight bearing area of the heel can be covered by local flaps, radiodermatitis is a contraindication to these flaps. Thin free flaps, as grafted fascial or muscles flaps and thin fasciocutaneous flaps, are usually the option of choice in these particular defects. These reconstructions are prone to shearing strains resulting in ulceration, hypertrophic scars and hyperkeratosis. The authors present a retrospective study of the reconstruction of six small heel defects with the fasciocutaneous temporal free flap performed between 1996 and 2001. The mean size of the defect was 20 cm2. All arterial anastomoses were performed end to side on the posterior tibial artery. Despite the flap thinness, swelling was present during 12 –25 months and one debulking had to be performed. With a mean follow-up of 32 months, all flaps regained protective sensibility after 7 months. No sliding of the flaps could be noted but there was one transient hyperkeratosis. Although the amount of hair on the transferred flaps decreased spontaneously with time, laser hair removal was performed in two patients for psychological reasons. In conclusion, it seems that in selected cases where local flaps are contraindicated, the fasciocutaneous temporal free flap can offer an excellent alternative for heel reconstruction. Due to its particular architecture, it resembles the complex tissue of the sole of the foot resulting in fewer complications and maintenance of flap durability. Q 2004 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved.
Reconstruction of soft tissue defects of the weight bearing surface of the foot is difficult. Although conventional local flaps can be used for the coverq Presented at the second meeting of the World Society of Reconstructive Microsurgery, June 2003 (Heidelberg, Germany). *Corresponding author. Address: Department of Plastic and Maxillo-Facial Surgery, CHU Sart Tilman, University of Lie `ge, Bat. B 35, Lie `ge B-4000, Belgium. Tel.: þ32-4-366-72-12; fax: þ 32-4366-70-61. E-mail address: [email protected]
age of small defects, extensive and more complex defects can only be treated by microsurgical flap transfer. Whatever flap is chosen, it is almost impossible to replace the functional complexity of the weight bearing area of the foot. Transferred tissues have to resist the shearing forces in order to prevent complications as ulcerations, hypertrophic scar formation and hyperkeratosis. The skin on the plantar area of the foot is the thickest in the body and is supported by dense subcutaneous tissue with
S0007-1226/$ - see front matter Q 2004 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2003.12.038
Covering small defects on the weight bearing surfaces of the foot
vertically oriented fibrous septae that anchor the plantar skin to the underlying fascia. In order to replace the soft tissue defect on the weight bearing area of the heel with an optimal free transferred substitute, we performed six free fasciocutaneous temporal flaps after debridement of plantar radiodermitis wounds. The subcutis of the scalp is traversed by dense connective tissue, binding the thick skin to the underlying fascia. In this respect, its complex architecture is histologicaly comparable with the heel structure (Fig. 1). The purpose of this small study was to review our experience with these fasciocutaneous temporal flaps for small defects on the weight bearing area of the heel.
Material and methods Between 1996 and 2001, we performed six heel reconstructions with a fasciocutaneous temporalis free flap in the weight-bearing area of the foot. Five women and one man, ranging in age from 27 to 52 years (mean 40.2) have been included in this study. They all presented with chronic wounds secondary to radiation therapy for recurrent warts (five) or Lederhose disease (one). No patient had osteomyelitis and all had clinically normal vasculature. The size of defects varied from 15 to 30 cm2 (mean 20 cm2). In all patients, the fasciocutaneous temporal flap was harvested in the classical way and one extra centimeter of fascia, surrounding the skin paddle was included in the flap. All donor sites were
461
closed primarily. All microsurgical arterial anastomoses were performed end to side on the posterior tibial artery while the venous anastomoses were performed end to end to one of the concomitant veins of the posterior tibial artery. In none of the flaps was the auriculo-temporal nerve harvested. The fascia, surrounding the skin paddle by 1 cm, was strongly attached to the periosteum around the defect in order to prevent sliding of the fascia on the bone.
Results The fasciocutaneous temporal flap was successful in all six cases with no flap necrosis. Revision of a venous anastomosis had to be performed in one case. During follow-up (mean 32 months), a persistent swelling of these thin flaps was obvious for 12 –25 months. In one patient, flap debulking had to be performed 20 months after transfer because the bulkiness had caused an ulceration of the flap. After debulking, the ulcer healed uneventful. We also noted one transient hyperkeratosis, but all other scars healed well without hypertrophy. Every transferred flap presented with hair growth without functional disability. However, the amount of hair decreased spontaneously with time, and laser hair removal was only performed for psychological reasons in two patients (Fig. 2). The assessment of gait was based on the authors’ subjective observation as the patient walked without footwear, and five patients regained a normal gait pattern postoperatively and could wear normal footwear of their usual size. Only one patient (who needed the flap debulking) had a slightly altered gait pattern and required larger footwear with silicone inlay. All patients had protective sensation after 7 months although no nerve coaptation had been performed peroperatively. The donor sites healed well although one patient suffered from transient alopecia and one patient presented with a widened scar after 6 months. However, no patient had to change his or her hairstyle. Due to the large undermining, essential to perform direct closure, all patients suffered from transient hypoesthesia during 5 months.
Discussion Figure 1 Comparable histological sections with the fibrous septae in the heel (arrows, A) and the dense connective tissue between the skin and the underlying fascia in the scalp (arrows, B).
Although defects of the weight bearing area of the heel can be covered by different local flaps such as the medial plantar flap, we regard radiodermatitis as a relative contraindication. In radiodermatitis
462
O. Heymans et al.
Figure 2 Clinical results. (A) Peroperative result. (B) Postoperative result after 3 months with apparent hair growth. (C) Result after 6 months with clearly less hair growth. (D) Result 1 year postoperatively after laser hair removal.
wounds, the defect is usually limited to the soft tissues, sparing the bony structure. The ideal free flap for reconstruction of the foot should be thin, so grafted fascial free flaps such as the serratus fascial flap, the temporal fascial flap or the radial forearm fascial flap, are usually preferred over bulky muscle flaps1,2 in smaller defects. However, due to its unique architectural characteristics, the heel skin is normally able to withstand pressure and shearing strains, preventing the complications which are often encountered after these free fascial flap procedures to the weight bearing area of the heel. The thick plantar skin and the underlying elastic adipose tissue allow the dispersion of vertical and horizontal shearing forces that accompany walking.3 Once reconstructed with other soft tissues, this specific dispersion is lost resulting in sliding of the foot on the flap during walking (Fig. 3). Unlike the neighbouring skin, the flap surface is not strongly attached to the calcaneum by fibrous septas. Free muscle flaps with skin grafts develop two independent mobile tissue planes: one at the muscle to the underlying tissue interface and a second at the skin graft to muscle free flap interface (Fig. 4(A)). Free fascial flaps can be strongly attached to the periosteum and sutured with tension over the calcaneum diminishing the sliding of the flap. These flaps, however, also have to be skin grafted so a mobile tissue plan still
persists at the skin graft to free flap interface. There is, however, a minimal mobile tissue plan between the fascia and underlying bone resulting in better resistance to shearing strains. In free fasciocutaneous flaps as the radial forearm flap, the same problem is encountered, even more obviously (Fig. 4(B)). The subcutaneous tissue represents a mobile tissue plane between the fascia, which can be strongly attached to the periosteum, and the skin. The sliding of the skin over the fascia is even more important than in grafted fascial flaps because of the subcutaneous layer, which is absent in grafted flaps. The architecture of a free cutaneous flap resembles more the subcutaneous elastic adipose architecture of the plantar surface, but they are often too bulky and they are difficult to attach to the underlying bone. The contralateral free medial plantar flap may represent the best solution because of the identical tissue characteristics. However, this flap has significant donor site considerations and entails that the noninjured foot will also have scars postoperatively. Although it has been suggested that free cutaneous flaps intrinsically resist shear forces4,5 and that different mobile planes allow resistance to tangential shear forces,6,7 we are convinced that the sliding of tissues plays an important role in the development of postoperative ulcerations,
Covering small defects on the weight bearing surfaces of the foot
463
Figure 3 Clinical effect of the shearing strains and the resulting sliding of a radial forearm flap after transfer to a heel defect. (A) Without shearing strains. (B) During shearing strains.
Figure 4 Schematic drawings after free tissue transfer. (A) Free muscle grafted with two sliding planes; one between the muscle and the bone, a second between the muscle and skin graft. (B) Free fasciocutaneous flap with the fascia strongly attached to the periostium leaving only one sliding plane. (C) The apparent connections of fibrotic tissue between the skin and underlying fascia in the scalp. (D) Free fasciocutaneous temporal flap with maximal resistance to shearing strains.
464
hyperkeratosis and hypertrophic scar formation. Grafted fascial free flaps are preferable over other flaps1,2,8 because of fewer postoperative complications. It is our opinion that this may be explained by the fact that these flaps can attach more strongly to the underlying bone and presents the less mobile tissue plans as mentioned above. In our search for the most similar substitute for the ‘irreplaceable’ heel skin, we performed histological sections of the scalp (Fig. 1). It is known that the subcutaneous layer of the scalp is transversed by dense connective tissue, binding the hair bearing scalp to the underlying fascia.9 This flap has already been used for a wide variety of reconstructive procedures and it has proven its reliability.10 – 12 In our opinion, this scalp tissue most resembles the heel tissue, and we think that the natural attachment of the temporo-parietal skin to the fascia is able to withstand the shearing strains and that these septae act as a shock absorbing system as do the fibrous septae in normal heel skin (Fig. 4(C) and (D)). In our small series, we were able to attach the temporal fascia strongly to the periosteum and thus preventing the first sliding plane as in the free fascial flaps. Thanks to the fibrous septa in the subcutaneous tissue, which are strongly adherent to the fascia, the second sliding plane is also reduced to a minimum. Resistance to the shearing forces is maximum leading to fewer postoperative complications as seen in our small series. Nevertheless, complications can occur since flaps on weight-bearing surfaces of the foot are more prone to ulcers than those on nonbearing surfaces. These ulcers seem to be independent of flap origin, flap sensibility and the cause of the primary defect.13 They are however, mechanical in origin and arise from exogenous and endogenous causes. The exogenous ulcers appear mostly on free flaps that are unusually thick and conform poorly to the osseous architecture of the foot. This may explain why we had the ulceration in the thick flap that healed uneventfully after flap debulking confirming our opinion that exogenous ulcers can be prevented by applying this thin fasciocutaneous flap. Ulcers from endogenous origin develop exclusively in conjunction with weight-bearing points and pressure sites overlying osseous deformities. These high pressure points are the most important reason for recurrent breakdowns, and can be prevented by paying attention to the normal skeletal architectural features of the foot during reconstruction.13,14 Not only resection of bony spurs, but also appropriate orthopaedic procedures should be performed and supportive footwear should be provided to obtain a better gait and prevent recurrent ulceration.15 Another important
O. Heymans et al.
issue is the tendency of larger defects to exhibit these ulcerations more frequently. Since our series deals with only small defects, we will not include this issue in our discussion. Discussion still exists as to whether sensory nerve coaptation should be performed or not. Even with noninnervated flaps, protective sensibility can be achieved after 1 year by most patients. Many authors advocate that the most important factor for the maintenance of flap durability is the presence of deep pressure sensation.15 Santanelli et al.8 concluded in their study that nerve coaptation should be used in young, healthy motivated patients to improve stability of the flap with an earlier return to load capacity and a full recovery to normal activity. Once again, their study included large defects and we think that it cannot be compared with the faster sensory recovery in small flaps as in our series. Whenever plantar reconstructions are performed, hypertrophic scars and hyperkeratosis may develop. These pathologic events seem to be provoked by shearing forces in somewhat bulky flaps, and can be solved by flap thinning and tightening in combination with scar revision and Z plasties.16,17 By transferring the fasciocutaneous temporal flap and thus, as mentioned above, diminishing the shearing strains, we only noticed one transient hypertrophic scar. The donor site morbidity, similar to a classical fascial temporal flap, consists mainly of alopecia in the immediate vicinity of the incisions. This however, may be transient and can be avoided by meticulous dissection. Another disadvantage is the transient hypoesthesia (5 months) of the undermined area, mandatory to obtain primary closure. Transferring hair-bearing skin to the plantar area may constitute some psychological problems for the patient, but had no functional repercussion. As time passed by, the number of hairs reduced significantly. Nevertheless, in two patients the remaining hairs were removed by laser techniques (ruby laser). The fasciocutaneous temporal free flap can provide a reliable wound coverage option in selected cases. We successfully used this flap in small defects on the weight-bearing area of irradiated heels where local flaps are contraindicated. Due to its specific anatomical structure, a natural contour could be restored that could withstand pressure and shearing strains. In this way, we think that the postoperative complications could be diminished with minimal donor site morbidity, although larger series with a longer follow-up have to be performed to confirm our findings.
Covering small defects on the weight bearing surfaces of the foot
References 1. Woods JM, Shack RB, Hagan KF. Free temporoparietal fascia flap in reconstruction of the lower extremity. Ann Plast Surg 1995;34:501—6. 2. Rainer C, Schwabegger AH, Bauer T, et al. Free flap reconstruction of the foot. Ann Plast Surg 1999;42:595—607. 3. May Jr JW, Rohrich RJ. Foot reconstruction using free microvascular free flaps with skin grafts. Clin Plast Surg 1986;13:681—9. 4. Russell RC, Guy RJ, Zook EG, Merrell JC. Extremity reconstruction using the free deltoid flap. Plast Reconstr Surg 1985;76:586—95. 5. Duncan MJ, Zucker RM, Mankletow RT. Resurfacing weightbearing areas of the heel: the role of the dorsalis pedis innervated free transfer. J Reconstr Microsurg 1985;1: 201—8. 6. Goldberg JA, Adkins P, Tsai TM. Microvascular reconstruction of the foot: weight-bearing patterns, gait analysis, and long term follow-up. Plast Reconstr Surg 1993;92:904—11. 7. May Jr JW, Halls MJ, Simon SR. Free microvascular muscle flaps with skin graft reconstruction of extensive defects of the foot: a clinical and gait analysis study. Plast Reconstr Surg 1985;75:627—41. 8. Santanelli F, Tenna S, Pace A, Scuderi N. Free flap reconstruction of the sole f the foot with or without sensory nerve coaptation. Plast Reconstr Surg 2002;109:2314—22. 9. Smith RA. The free fascial scalp flap. Plast Reconstr Surg 1980;66:204—9.
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