Soft-tissue coverage of the middle and distal third of the leg represents a problem due to the inherent characteristics of the lower limb, paucity of soft tissues, bone prominences, diameter, and biomechanics. A simple defect can turn into a major challenge, for which several therapeutic options have been described.1–4
The approach for soft-tissue coverage is based on the wound size and its location, contamination, types of tissues involved, and functional requirements. Additional factors include the area and extension of the zone of injury, the length and diameter of the pedicle if a free flap is performed, donor-site morbidity, bone fixation type, and aesthetic outcome.5,6
Local options for reconstruction and coverage of defects in the distal third of the leg are limited. The cross-legged flap popularized by Stark7 was used in his time with much popularity; however, today it is performed very little because of its high morbidity of the donor site and the necessary immobilization of both lower extremities.
Although free microsurgical flaps have been the first choice for reconstructive procedures in the leg, there are some local flaps that may be of choice in some cases, providing adequate coverage of cutaneous defects.
As the use of free flaps has been broadly practiced, the innovation and technical refinement has allowed the evolution of flaps applied to the lower extremity, including perforator-based flaps or freestyle flaps.8
The availability and better understanding of the vascular axes anatomy of the leg, its interrelation with muscle groups, and lower morbidity have motivated the use of pedicle perforator flaps. The techniques described in the dissection of perforator flaps from anatomical studies have provided a variety in the design of pedicle flaps.9,10
The perforator flaps are very attractive as a resource, because it has diversity with more than 500 perforating vessels. In the upper limb, there are an average of 48 perforators from 15 vascular territories, and in the lower limb, we can find 93 from 21 territories.11 The perforator propeller flaps are versatile in our therapeutic armament, initially described by Hyakusoku et al.,12 to define a method in which a flap with a length exceeding its width is rotated 90 degrees on its central axis based on a central subcutaneous pedicle. It was technically refined by Teo13 with a higher degree of rotation by completely releasing the perforating vessel as a single pedicle, which led to its subsequent definition and classification.14
The application of the pedicle perforator flaps and its propeller variant for leg reconstruction has many advantages. The main artery and underlying muscle are preserved, and the need to perform a microsurgical anastomosis is avoided. Dissection of the flap is relatively fast, and it has the thickness, texture, and pigmentation of the site that has been lost, replacing with the “like with like” principle15 (Fig. 1).
In the present study, the main goal was to justify the use of local perforator propeller flaps as a surgical alternative for the coverage of soft-tissue defects of small-medium size in the lower and middle third of the leg, with low morbidity of the donor site and low complications, being reproducible in different hospital centers.
MATERIALS AND METHODS
A retrospective study was made between June 2012 and June 2017 of the perforator propeller flaps done by the authors in different hospitals of Managua, Nicararagua, in patients with soft-tissue defects of the mid-distal third of the leg. Clinical records of the patients were reviewed with the recollection of the patients’ personal data, diagnosis, perforator flap used, complications, and postoperative results.
The procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (Instutionational and National Autonomous University of Nicaragua) and the Helsinki Declaration of 1975, as revised in 2000. Informed consent was obtained from the patients included in this study.
The sample consisted of 28 patients, in whom a total of 28 flaps were performed for the reconstruction of defects of the middle and distal third of the leg. Patients with concomitant involvement of the proximal third of the leg were not included in the sample.
The information obtained was processed in SPSS 15.0 comprehensive system for analyzing data, for the description of categorical variables, using absolute and relative frequencies [n (%)] and for comparison chi-square test; numerical variables were described regardless of whether they showed normal distribution or not, with median and SD (M ± DE) or with a median and interquartile range [Md (25–75)] and compared with Student’s t test or Mann-Whithey U test as corresponded. It was considered statistically significant if P < 0.05. Simple or complex tables were produced for crossing variables and graphs as appropriate.
The process of selecting the vascular axis of the leg (anterior tibial artery, peroneal or posterior tibial artery), on which to base the perforating vessel of the propeller flap, was done by preoperative auscultation with a Nicolet handheld Doppler with a 8-Mhz probe, with an angulation of the probe of approximately 45 degrees to the skin surface, according to the location of the defect to be covered. A provisional flap design can be drawn as follows, with the perforator as the pivot point of the flap, as its been described previously.13 First, the distance between the perforator and the distal edge of the defect is measured. This value is then transposed proximally along the axis of the main source vessel, again measured from the perforator, and 1 cm is added. This value forms the proximal limit of the flap. Next, the width of the proximal flap needed to cover the defect is determined by measuring the width of the defect. This value is then used to determine the proximal flap width, adding 0.5 cm to allow for flap contraction and to facilitate its inset without tension. The lateral dimensions are equidistant to ensure that when the flap is eventually rotated around to fill the defect, there is no excessive sideways traction on the perforator during wound closure.
We performed a first longitudinal skin incision on 1 of the margins of the flap to observe the perforator localized preoperative with the handheld Doppler.
The distance of the perforator from the proximal edge of the defect determined the length of the minor paddle used to cover or partially cover the donor site. If direct closure of the donor site was not achievable, a skin graft was used to close the residual defect.
The elevation of the flap was performed with the patient in supine position, occluding the flow of the leg for 1 minute with digital compression on the popliteal artery, without performing exsanguination of the extremity with an elastic bandage, and at the thigh a controlled tourniquet was placed with a continuous pressure of 250 mm Hg. The flap is dissected, under 2.5× magnification, subfascially or suprasfascially, with an axial orientation with respect to the affected limb, always releasing the perforating vessels of all the muscular branches and adhesions, with dissection of the pedicle at least 2 cm as it has been recommended16 (Fig. 2). Once the pedicle has been dissected, the ischemia is released to assess the irrigation of the flap and before its transposition, it is left in its native orientation for 10 minutes to then corroborate the adequate capillary filling of the borders of the flap. In case of finding more than 1 vessel, a microclamp is placed on 1 of the vessels to base the flap in only 1 perforator to allow a rotation of up to 180 degrees (Fig. 3).
The area of extension in cm2 of the flap transposed, degrees of rotation of the flap, its complications, and the ability to perform a primary closure of the donor site were all evaluated.
In the period of the study, 28 patients were treated in which we perform a total of 28 flaps for the coverage of defects localized at the middle and distal third of the leg, caused by trauma, with a ranging age from 19 to 65 years (mean, 32 years), with an interquartile range of 25 and 42, being the male sex the most frequent in 21 cases (75%). Among the patients, 3 had comorbidities of diabetes mellitus and hypertension (Table 1).
Among the affected areas that required coverage of soft tissues of the leg, in order of frequency, the middle third represented 18 cases (64.3), and in the distal third 10 cases (35.7%).
Flap dimensions ranged from 12 to 156 cm2, with an average size of 50 cm2 with interquartile range of 30 and 60 cm.2
The flap rotation was 180 degrees in 23 cases (82%), 140 degrees in 3 cases (11%), and 160 degrees in 2 cases (7%).
The flaps were based on a single perforating vessel of the posterior tibial artery in 14 cases (50%) of the cases; on the anterior tibial artery in 11 cases (39.3%), and in 3 cases (10.7%), the peroneal artery was chosen.
Complications were present in 14% of the flaps. These included 3 partial necrosis less than a 15% of the flap, which were all based in the posterior tibial artery, and 1 case with an epidermolysis of the flap based in the anterior tibial artery without a statistical difference with respect to the artery used to base the flap. Female patients presented complications in 42.9% with a tendency toward statistical significance (P = 0038) according to sex.
Primary closure of the donor site was performed in 24 cases (85.7) of which 16.7% (4) had complications. The registered complications of partial necrosis and epidermolysis of the flaps were among the group in which the primary closure of the donor site was treated with a partial thickness skin graft, which had a 100% integration (Fig. 4).
Propeller perforator flaps are a reliable option for a stable coverage of mid-distal third defects of the leg, where the design of the flap is based on perforators, in relation to the localization and size of the defect.
Traditional reconstructive tools for the lower limb suggests local flaps for coverage in the thigh and proximal thirds of the leg areas as choice, while microvascular flaps are most useful for the distal third of the leg and foot, due to the paucity of local tissues to base locoregional flaps.5,7,14 However, the use of fasciocutaneous local flaps, basing its vascularity on the fascial plexus and not necessarily on the identification of a specific cutaneous vessel in the 1980s by Pontén1 and Hallock2, opened new gates to the reconstruction of the soft tissues of the lower extremity. Nakajima et al.10 subsequently demonstrated that this fascial plexus was nourished by deep fascial perforating vessels from the underlying main vessels of the limb.
Refinements for the application of flaps has led to the development of perforator flaps. The perforator flaps have evolved from musculocutaneus and fasciocutaneous to nonutilization of muscle or fascia as irrigation transporters, from the major vessels of the lower extremity, and bearing this in mind has driven our interest in using these flaps with the benefit of providing a similar coverage to neighboring tissues and favoring a primary closure, in small size defects. The flaps made had average dimensions of 48 cm,2 which are close to the concept proposed by Morris et al.11, that a perforating vessel of 0.7 cm provides an approximate irrigation of 47 cm2 and may even have a broader extension as described by Gir et al.17 of 67.1 cm.2,18
The ability to rotate the propeller perforator flaps up to 180 degrees, which we performed in 82% of the cases, makes it extremely versatile to reconstruct defects of the middle and distal third of the leg, as has been reported in other series.12,14,17,19
In our study, we found 4 complications (14%), 3 partial necrosis, and a superficial epidermolysis, which is lower than that reported in the meta-analysis performed by Gir et al.17, reporting complications of 25.8%, with partial necrosis being the more common in 11.3%. The percentage of complications is similar to that of free flaps, 16–38%, and in terms of total necrosis is lower, because in free flaps it is 4–19%,4,5,8 compared with 1.1% in propeller perforating flaps.17
Another possible described factor that may be associated with partial necrosis of the flaps is the inclusion of scar tissue in the flap design, or excessive tension in the closure of the defect.13 This is why sometimes recommended the laminar skin graft for the donor site of the flap, which will always become a more common option as the defect is more distal, due to the lack of displacement of the tissues in the leg, as we did in 14.3% of the cases.
Although no differences have been found in the relationship of flap complications and sex,16,17 in the present study it was found that in the female sex there is a certain association with complications, which may be related to hormonal effect on the venous system, although the sample size of female patients was low.20
A useful tool in the planning of perforator flaps is the manual unidirectional acoustic Doppler,21,22 in all patients preoperatively as a guide for vessel location and flap design. In our practice, we used a handled Doppler with a 8 Mhz probe. Khan and Miller22 use a handheld Doppler with 8–10 MHz probes, reporting a sensitivity of 90% with a confidence interval of up to 95%, positive predictive value of 84% with a reliability interval of 74–91%. The transducer is angled approximately 45 degrees to the surface of the skin, because performing it parallel to the skin may increase the possibility than an axial vessel; our source vessel will be selected instead of a perforator.22
The transoperative confirmation of the position of the perforators allows redesigning the flap, with few modifications, and basing them according to its location in a perforator of the main vessels of the limb,9,13,15 so that on 3 occasions we modified the original design, extending proximally to achieve adequate coverage.
Perforator propeller flaps preserve the major vascular axes of the limb and underlying muscle, avoiding the need for a microsurgical anastomosis and the benefit of providing a tissue-like covering. These flaps have a consistent and predictable blood supply, at least 1 perforating vessel greater than 0.5 mm, a pedicle long enough for the required transposition, and ability to close the donor site in a primary fashion13 (Fig. 5).
The advantages of the propeller perforator flap include lower morbidity of the donor site, primary closure in most cases, versatility in flap design, and muscle preservation with less functional deficit of the leg.
Its disadvantages are the need to perform a meticulous dissection to isolate the perforating vessels, variability in the position and size of the perforating vessels, and ease of being able to damage the vessels.
Based on the results obtained in our study, we consider that perforator propeller flaps are ideal in reconstructing small-medium defects of the middle and distal third of the leg, being safe, easy to perform, providing similar tissue in texture and thickness of damaged tissues, with low donor-site morbidity.
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2. Hallock GG. Local fasciocutaneous flaps for cutaneous coverage of lower extremity wounds. J Trauma. 1989;29:1240–1244.
3. Conejero A, Dagnino B, Pereira N. Experiencia en reconstrucción de tercio distal de pierna con colgajo libre de músculo gracilis. Cir plást iberolatinoam. 2013;39:279–283.
4. Engel H, Lin CH, Wei FC. Role of microsurgery in lower extremity reconstruction. Plast Reconstr Surg. 2011;12:228–238.
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6. Parrett BM, Matros E, Pribaz JJ, et al. Lower extremity trauma: trends in the management of soft-tissue reconstruction of open tibia-fibula fractures. Plast Reconstr Surg. 2006;117:1315–1322; discussion 1323.
7. Stark RB. The cross-leg flap procedure. Plast Reconstr Surg (1946). 1952;9:173–204.
8. Hallock GC. A paradigm shift in flap selection protocols for zones of the lower extremity using perforator flaps. J Reconstr Microsurg. 2013;29:233–240.
9. Schaverien M, Saint-Cyr M. Perforators of the lower leg: analysis of perforator locations and clinical application for pedicled perforator flaps. Plast Reconstr Surg. 2008;122:161–170.
10. Nakajima H, Fujino T, Adachi S. A new concept of vascular supply to the skin and classification of skin flaps according to their vascularization. Ann Plast Surg. 1986;16:1–19.
11. Morris S, Tang M, Geddes CR. Bases anatómicas vasculares de los colgajos perforantes cutáneos. Cir Plást Iberlatinamer Dic. 2006;32:225–236.
12. Hyakusoku H, Yamamoto T, Fumiiri M. The propeller flap method. Br J Plast Surg. 1991;44:53–54.
13. Teo TC. Reconstrucción de la extremidad inferior con colgajos de perforantes locales. Cir Plas Iberolatinoam. 2006;32:15–16.
14. Pignatti M, Ogawa R, Hallock GG, et al. The “Tokyo” consensus on propeller flaps. Plast Reconstr Surg. 2011;127:716–722.
15. Laredo Ortiz C, Restituyo G, Castillo L, et al. Variabilidad en el diseño y composición del colgajo de perforante de tibial posterior para la reconstrucción de defectos en la pierna. Cir Plást Iberolatinoam. 2011;37:21–31.
16. Lecours C, Saint-Cyr M, Wong C, et al. Freestyle pedicle perforator flaps: clinical results and vascular anatomy. Plast Reconstr Surg. 2010;126:1589–1603.
17. Gir P, Cheng A, Oni G, Mojallal A, Saint-Cyr M. Pedicled perforator (propeller) flaps in lower extremity defects: A systematic review. J Reconstr Microsurg 2012; 28: 595–601.
18. Saint-Cyr M, Wong C, Schaverien M, et al. The perforasome theory: vascular anatomy and clinical implications. Plast Reconstr Surg. 2009;124:1529–1544.
19. Hallock GG. Direct and indirect perforator flaps: the history and the controversy. Plast Reconstr Surg. 2003;111:855–865; quiz 866.
20. Ciardullo AV, Panico S, Bellati C, et al. High endogenous estradiol is associated with increased venous distensibility and clinical evidence of varicose veins in menopausal women. J Vasc Surg. 2000;32:544–549.
21. Panagiotopoulos K, Soucacos PN, Korres DS, et al. Anatomical study and colour Doppler assessment of the skin perforators of the anterior tibial artery and possible clinical applications. J Plast Reconstr Aesthet Surg. 2009;62:1524–1529.
22. Khan UD, Miller JG. Reliability of handheld Doppler in planning local perforator-based flaps for extremities. Aesthetic Plast Surg. 2007;31:521–525.