Journal of Plastic, Reconstructive & Aesthetic Surgery (2010) 63, e525ee528

Prefabricated flap composed by skin and terminalgastromental vessels. Experimental study in rabbits

Jason Cesar Abrantes de Figueiredo a,b, Renato Rodrigues Naufal a,b,Francisco Claro de Oliveira Jr b,*, Victor Arias c,Paulo Roberto Bueno Pereira d, Luıs Marcelo Inaco Cirino d

a Brazilian Society of Plastic Surgery, Sao Paulo, SP, Brazilb Santa Cruz Plastic Surgery Institute, Sao Paulo, SP, Brazilc Laboratory of Medical Research (LIM 26), Faculty of Medicine, ‘‘Universidade de Sao PauloeUSP’’, Sao Paulo, SP, Brazild Department of General Surgery, Faculty of Medicine, ‘‘Universidade de Sao PauloeUSP’’, Sao Paulo, SP, Brazil

Received 6 August 2009; accepted 23 January 2010

KEYWORDSPrefabricated Flap;Omentum;Pedicle;Skin

* Corresponding author. ‘‘Universida04122-000 Sao Paulo, SP, Brazil. Tel.:

E-mail address: fclarojr@gmail.com

1748-6815/$-seefrontmatterª2010Britdoi:10.1016/j.bjps.2010.01.033

Summary Background: The angiogenic induction property of the omentum makes it a prom-ising pedicle for prefabricating flaps. Therefore, the objective of this paper is to establish theabdominal area to be prefabricated by the omental pedicle and to analyse the prefabricatedpotential (PP) according to the time delay between the pedicle introduction and the flaprelease.Methods: Forty-four rabbits were divided into four groups (A, B, C and D). In group A, a piece ofskin, subcutaneous tissue and abdominal cutaneous muscle was fully released and suturedagain in place. In the other groups, a 9-cm2 omental pedicle containing the gastromentalvessels distally tied was transposed and sutured to abdominal cutaneous muscle. A secondprocedure, consisting of incision and release of the flap that contained skin, subcutaneousand cutaneous abdominal muscle pediculated only by the omentum, was carried out. The onlyvariation was the time delay between the two procedures: 7, 21 and 56 days for groups B, Cand D, respectively. The flaps were inspected 15 days after the last procedure. The piecesof viable area were immunostained using anti-CD31 for estimation of the microvasculardensity.Results: The mean and maximum viable areas in group D were 45.29 and 99.37 cm2, respec-tively (average PP Z 5.03 and maximum PP Z 11.04). There was no significant differencebetween the viable areas in groups C and D. The mean microvascular densities of groups B,C and D were 24.54, 33.20 and 27.03 vessels/mm2, respectively.

de de Sao Paulo e USP’’, Instituto de Cirurgia Plastica Santa Cruz, Rua Santa Cruz, 398eVila Mariana,þ55 11 93205686; fax: þ55 11 55759863.

(F. Claro de Oliveira Jr).

ishAssociationofPlastic,ReconstructiveandAestheticSurgeons.PublishedbyElsevierLtd.All rightsreserved.

e526 J.C.A. Figueiredo et al.

Figure 1 On a rabbit from the Goperatory phase. (B) The flap and ththe last procedure performed. (D) S

Conclusion: The omental tissue has great potential for prefabrication of flaps, and the delaytime for the second procedure should be at least 21 days.ª 2010 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published byElsevier Ltd. All rights reserved.

The omentum has been used to promote healing and neo-vascularisation of ischemic tissues, including myocardiumand intestinal anastomosis.1 This tissue has a high concen-tration of vascular endothelial growth factor (VEGF).2

The objective of this paper is to quantify the potentialfor prefabrication of the omentum and gastromentalvessels of skin flaps as well as the influence of the waitingperiod between the placing of the pedicle and the releaseof the flap.

Methods

Forty-four New Zealand breed white male rabbits treatedaccording to the standards recommended by the BrazilianCollege of Animal Experimentation were divided into fourgroups (A, B, C and D). In group A, a piece of skin, subcu-taneous tissue and abdominal cutaneous muscle (ACM) wasfully released and sutured again in place. In the othergroups, a 9-cm2 omental pedicle containing distally tiedgastromental vessels was transposed and sutured to theACM. A second procedure, consisting of a flap of 150 cm2

that contained skin, subcutaneous and ACM, pediculatedonly by the omentum, was carried out. The only variation

roup D: (A) Omental pedicle ate omental pedicle in the seconlide imunostained with anti-CD

was the time delay between the two procedures: 7, 21 and56 days for groups B, C and D, respectively. The flaps wereinspected 15 days after the last procedure.

Three areas were defined as follows: total original area(TOA), viable area (VA) and area of necrosis (AN). The areaof the omentum in contact with the flap was called thepedicled area (PA) and was considered to have a constantvalue of 9 cm2. The potential for prefabrication (PPF) wascalculated by the ratio between viable and pedicle areas.The flaps were divided into four segments. A similar frag-ment in the contralateral region of the abdomen wasremoved and treated with the same cuts as the flap in eachrabbit.

Histological sections of four micrometres were preparedon slides previously silanised by Organosilano�, stained byHematoxylin/Eosin and by anti-CD31 by DAKO� and by anamplification kit (Novocastra�).

The microvascular density (MD) was assessed micro-scopically with an amplification of 250 times. Four adjacentareas of 0.41 mm2 each with increased MD were selectedand images were captured in each histological section. Thesum of the number of vessels was divided by 1.64 to obtainthe number of vessels per square millimetre (v/mm2)(Figure 1).

tached to the cutaneous aponeurotic muscle (CAM) in the firstd operatory phase (p). (C) Analysis of the flaps after 56 days of31 to assess the microvascular density (amplification of 250).

Prefabricated flap composed by skin e527

The data from this study were analysed by an adoptedlevel of significance of 5% (a Z 0.05).

Results

The average viable areas in groups A, B, C and D were0.00 cm2, 2.89 cm2, 21.94 cm2 and 45.29 cm2, respectively.The average potential for prefabrication (median VA/9) ingroups B, C and D were 0.32, 2.44 and 5.03 (maximum

Table 1 Areas, ratio of areas and of microvascular density (v/m

Flap VAa (cm2) TFAb (cm2) TOAc (cm2) Dd RC

A1 0 39.62 150 110.38 0.A2 0 62.64 150 87.36 0.A3 0 40.26 150 109.74 0.A4 0 65.61 150 84.39 0.A5 0 51.39 150 98.61 0.A6 0 56.22 150 93.78 0.A7 0 46.09 150 103.91 0.A8 0 49.37 150 100.63 0.B1 0 39.74 150 110.26 0.B2 0 56.06 150 93.94 0.B3 0 59.36 150 90.64 0.B4 5.4 82.4 150 67.6 0.B5 5.1 30.2 150 119.8 0.B6 0 40.85 150 109.15 0.B7 0 43.91 150 106.09 0.B8 17.39 47.25 150 102.75 0.B9 0.53 62.33 150 87.67 0.B10 0.64 53.15 150 96.85 0.B11 0 57.43 150 92.57 0.B12 5.6 56.74 150 93.26 0.C1 0 46.66 150 103.34 0.C2 16.97 64.95 150 85.05 0.C3 9.55 61.75 150 88.25 0.C4 21.23 72.92 150 77.08 0.C5 16.09 75.49 150 74.51 0.C6 92.75 117.39 150 32.61 0.C7 40.48 64.05 150 85.95 0.C8 24.74 82.81 150 67.19 0.C10 0 45.99 150 104.01 0.C11 11.33 64.73 150 85.27 0.C12 8.21 54.38 150 95.62 0.D1 99.37 101.78 150 48.22 0.D2 93.37 107.85 150 42.15 0.D3 25.47 84.41 150 65.59 0.D4 8.25 75.43 150 74.57 0.D5 9.29 51.58 150 98.42 0.D6 91.63 117.02 150 32.98 0.D7 33.1 77.78 150 72.22 0.D8 68.55 98.85 150 51.15 0.D9 63.38 99.29 150 50.71 0.D10 9.66 66.15 150 83.85 0.D11 14.66 81.95 150 68.05 0.D12 26.72 84.09 150 65.91 0.

a Viable area.b Total Final Area.c Total Original Area.d TOA-TFA.e Rate of Contraction Z D/TOA.

11.04), respectively. Applying the least squares regressionto the mean of viable area resulted in a curve that tendedto stabilise around 56 days. The average number of vesselsper mm2 did not demonstrate a tendency for progressivegrowth over time and showed patterns similar to those ofthe control areas. However, the values for the areas of theflap were larger (Table 1).

Applying the KruskaleWallis test between pairs of thesame parameters showed no statistical significance for any

m2) in each flape VA/TFA (%) VA/TOA (%) TFA/TOA (%) v/mm2

74 0 0 0.2658 0 0 0.4273 0 0 0.2756 0 0 0.4466 0 0 0.3463 0 0 0.3769 0 0 0.3167 0 0 0.3374 0 0 0.2663 0 0 0.376 0 0 0.445 0.07 0.04 0.55 24.088 0.17 0.03 0.2 7.3172 0 0 0.277 0 0 0.2968 0.37 0.12 0.3 12.6558 0.01 0 0.4165 0.01 0 0.35 26.8361 0 0 0.3862 0.1 0.04 0.38 51.8369 0 0 0.3157 0.26 0.11 0.43 32.3259 0.15 0.06 0.41 45.1251 0.3 0.14 0.49 32.935 0.21 0.11 0.5 60.372 0.79 0.62 0.78 23.7857 0.63 0.27 0.43 2545 0.3 0.16 0.55 31.769 0 0 0.359 0.18 0.08 0.43 30.4964 0.15 0.05 0.36 17.0732 0.98 0.66 0.68 19.5129 0.87 0.62 0.72 57.9344 0.3 0.17 0.565 0.11 0.06 0.566 0.18 0.06 0.34 22.5622 0.78 0.61 0.78 36.5848 0.43 0.22 0.5234 0.69 0.46 0.66 25.9734 0.64 0.42 0.66 20.3256 0.15 0.06 0.44 21.3445 0.18 0.1 0.55 18.944 0.32 0.18 0.56 20.12

e528 J.C.A. Figueiredo et al.

value between groups A and B, B and C, and C and D.Differences between groups A and D for all items werestatistically significant; between groups B and D, only themicrovascular density did not show significance.(p Z 0.2589). When applying the ANOVA test for the MDbetween paired areas of flap and control, the differenceswere statistically significant when the values were analysedtogether (p Z 0.034633). The vessels of the omental pedi-cles proved to be permeable, with no signs of thrombosis.

Discussion

The microvascular density averages were similar betweengroups B, C and D (24.54 v/mm2, 33.20 v/mm2 and 27.03v/mm2, respectively) and higher than the control areas(14.63 v/mm2, 17.33 v/mm2 and 18.12 v/mm2, respec-tively). These results suggest that after seven days themicrovascular density remained constant, and the vesselsonly radiated up to the most distant areas from the pedicle.

The clinical use of potential for prefabrication usingomentum is still limited to some cases of breast recon-struction.3 However, the omental flap can be easilyobtained and implemented in many target area as well asused as a temporary carrier pedicle4,5; moreover, it can beused several times. The potential for prefabrication may beuseful in reconstruction of wounds poor in receptor vessels,or when the vessels are located far from the wound,avoiding the use of venous grafts and simplifying thereconstruction of lesions in critical areas.

The omental tissue has great potential for prefabricatingflaps. The ideal waiting time to perform the secondprocedure in the prefabrication process of an omental flapis at least 21 days.

Financial disclosure and products page

None of the authors has any financial disclosures orcommercial associations that might pose or createa conflict of interest with the information presented in thisarticle.

References

1. Vineberg A, Syed AK, Pirozynski WJ. Rapid development in dogsof intramyocardial vascular pathways after implantation ofbloodless omental strips in the right and left ventricularmyocardium. Can J Surg 1968;11:219e28.

2. Zhang QX, Magovern CJ, Mack CA, et al. Vascular endothelialgrowth factor is the major angiogenic factor in omentum:mechanism of the omentum-mediateed angiogenesis. J Surg Res1997;67:147e54.

3. Erol OO, Spira M. Reconstructing the breast mound employinga secondary islandomentalflap. Plast Reconstr Surg 1990;86:510e8.

4. Furukawa H, Yamamoto Y, Kimura C, et al. Clinical applicationof expanded free flaps based on primary or secondary vascu-larization. Plast Reconstr Surg 1998;102:1532e6.

5. Liebermann DMI, Kaufmann M. Utilization of the greateromentum in surgery: a historical review. Neth J Surg 1991;43:136e45.