Caso Clínico

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Reconstruction of the scalp with a free flap of omentum
Reconstrucción de cuero cabelludo con colgajo libre de omentum

 

C. Navarro Cuellar¹, F. Riba García¹, B. Guerra Martínez², R. Pujol Romanya¹, H. Herencia Nieto¹,
C. Navvarro Vila³

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Abstract: Scalp defects may have different etiologies. Oncologic resections, postraumatic lesions and infectious wounds may lead to a great variety of defects in size and extension. In order to accomplish the reconstruction we have different surgical techniques such as local and regional flaps and tissue expanders. Nevertheless, for more extensive defects free flaps are the only reconstructive possibility. We present the case of a patient with multicentric squamous cell carcinomas previously with radiotherapy. He underwent wide resection and was reconstructed with an omentum free flap. Keywords: Scalp; Omentum free flap.

Resumen: Los defectos de cuero cabelludo pueden tener una etiología diversa. Resecciones oncológicas, lesiones postraumáticas e infecciosas pueden dar lugar a diferentes defectos en cuanto a tamaño y extensión. Para su reconstrucción disponemos de múltiples técnicas quirúrgicas como colgajos locales, regionales y expansores titulares. No obstante, para defectos extensos los colgajos libres son la única posibilidad reconstructiva. Presentamos el caso de un paciente con carcinomas epidermoides multicéntricos en cuero cabelludo tratado previamente con radioterapia en el que se realizó una resección amplia del cuero cabelludo y fue reconstruído con un colgajo libre de omentum. Palabras clave: Cuero cabelludo; Colgajo libre de omentum.

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1 Médico Residente
2 Médico Adjunto
3 Jefe de Servicio. Catedrático de Cirugía Maxilofacial
Servicio de Cirugía Maxilofacial
Hospital General Universitario Gregorio Marañón. Universidad Complutense, Madrid

Correspondencia:
Carlos Navarro Cuéllar
C/ María Molina 60, 7ºA
28006 Madrid
E-mail: cnavarrocuellar@mixmail.com

 

Introduction

The scalp is an area which is richly vascularized and which has classically been described with the following acronym: SCALP (S: skin; C subcutaneous tissue; A, aponeurosis or galea; L, loose connective tissue; P, pericranium)1. All these layers have an important anatomical consistency with the exception of the layer in the temporal region where we find the temporoparietal fascia, which then becomes galea by the inferior temporal line, and the fascia of the temporalis muscle with its muscle situated between the galea and the pericranium.

The scalp is relatively inelastic compared with the rest of the cervicofacial tissues. This is largely due to the fibrous union formed by the galea with the frontal muscle in front and the occipital muscle behind.¹ Most scalp flaps as a consequence resist traction and transposition, and they often require more extensive designs for closing defects.

On the other hand, the scalp has the great advantage of its rich vascular supply. Irrigation to the scalp is done by five vascularized pedicles in each side, namely: the supratrochlear artery, the supraorbital artery, the superficial temporalis artery with its frontal and parietal branches, the posterior auricular artery and occipital artery. All these vessels allow anastomosis and they cross the mid-line in order to connect with the contralateral vessels. All this rich vascular network gives the scalp great resistance to necrosis in its flaps.²

The defects of the scalp can be produced by multiple etiologies (oncologic resection, post-traumatic defects, infections, etc.). This reconstruction can be done in different ways depending, fundamentally, on the type and extension of the defect. Primary closure, second intention healing, tissue expanders, skin grafts, local flaps are the classic methods for the reconstruction of scalp defects that are not very extensive. Nevertheless, larger defects cannot be reconstructed by means of this technique and microvascular flaps are needed for their repair.

The omentum free flap was first used by Kiricuta³ in 1963 for breast reconstruction in oncologic surgery. Later Dupont and Menard⁴ used this flap for reconstructing thoracic defects demonstrating its capacity for providing volume and its considerable vascularization.

In 1972 McLean and Buncke⁵ used the omentum for the first time as a free flap for the reconstruction of a scalp defect, covering it with a dermoepidermic graft. Brown6 described the repair of a defect in the middle third of the face with a rib graft and an omentum flap for providing volume. Wallace⁷ and Upton⁸ used this flap for the reconstruction of hemifacial atrophy, and Panje^9,10 for treating maxillary and mandibular osteoradionecrosis. From then on, the omentum free flap has been used extensively for the reconstruction of the head and neck.

Clinical Report

We present the case of a sixty-eight year old patient with no hair on his scalp, who had a history of inguinal hernia on the right side that had not been operated on, and with an actinic keratosis which had persisted for years which had initially been treated with retinoids and cryotherapy. Two years later the patient reported the appearance of various scabby lesions in the parieto-occipital region. Biopsies were performed on the lesions which were reported as squamous cell carcinoma with a moderate grade of differentiation. The lesions were removed and one of the margins was affected by the tumor. The patient's scalp underwent maximum dosage radiotherapy. Six months later, the patient reported the appearance of various lesions similar to the previous ones which were in the same area. New biopsies were performed and squamous cell carcinoma was reported. The patient was then sent to our Service so that the therapeutic possibilities could be evaluated. On arrival the patient presented two scabby lesions with a diameter of approximately 2 and 3 cm respectively, together with other smaller lesions that were suspicious for malignancy. Similarly, and as a consequence of the radiotherapy, the patient presented fibrosis and complete retraction of the scalp that impeded any type of reconstruction with local flaps. Studied during a clinical session, ample resection of the scalp was decided upon, together with immediate reconstruction of the defect using an omentum free flap and a herniorraphy to reduce the inguinal hernia the patient presented (figs. 1 y 2).

The patient was operated on in conjunction with the Service of General Surgery and a simultaneous two-team approach was used. On the one hand extensive extirpation was carried out of the scalp together with a bilateral preauricular approach in order to identify and isolate the superficial temporal vessels. On the other hand, a medial laparotomy was performed. Once the abdominal cavity had been explored, the omentum was tractioned and dissected from the transverse mesocolon upwards. Next the vascular pedicle corresponding to the right gastroepiploic vessels was identified and exposed, and the small vascular branches that run to the anterior and posterior greater curvature of the stomach were exposed and ligated. Once the vascular pedicle of the greater curvature of the stomach had been freed, the pedicle of the left gastroepiploic artery was ligated leaving the omentum pedicled to the right gastroepiploic artery and ready to be transferred to the area of the defect. The omentum was then sutured to the remaining scalp and the anastomoses carried out. Some authors use both vascular pedicles with double anastomosis to the facial vessels and to the superficial temporal [vessels]. ⁸ In this case of ours, anastomosis was carried out using only the right gastroepiploic [artery], and the superficial temporal artery and vein were used as receptor vessels. Finally all the omentum flap was covered with a dermoepidermic mesh graft and a compression bandage was applied for one week. The surgical specimen was reported as squamous cell carcinoma with a moderate grade of differentiation and there were two carcinomas in situ, all with disease free margins. There were neither incidences nor complications during the postoperative period, and the patient was sent home 12 days after surgery (figs. 3 y 4). The patient attended numerous check ups and 2 years after the surgery there are no signs of local recurrence. From the aesthetic point of view the patient is very satisfied with the result, as the marks from the mesh have over time disappeared from his skin, and the tissue is uniform over his entire scalp.

Discussion

Reconstruction of the scalp depends basically on the type, location and extension of the defect that has to be reconstructed, and there are multiple techniques for doing this. Primary reconstruction can be used for small defects of various centimeters. The inconveniences of this technique are residual alopecia and the limited elasticity of the scalp which only permits the closure of limited defects. In order to reduce the tension of the closure, incisions should be made in the galea parallel to the borders of the wound.

Second intention healing, despite not being commonly used, can be an elective form of treating the scalp. Nevertheless, it has numerous inconveniences such as the absence of hair in the area, fibrosis, retraction and the development of atrophic scars, telangiectasias needing multiple treatments to avoid overinfection.

Skin grafts are another classical option used for reconstructing this type of defect. For these grafts to take adequately in the recipient bed, richly vascularized tissue is needed underneath such as pericranium or fascia (figs. 5 y 6). As in the case of second intention healing, this technique should be limited as the aesthetic result is poor and there is a tendency for bleeding, pain and ulceration.

Tissue expanders have been widely used for reconstructing scalp defects. A Silastic ball is placed under the galea which is then filled progressively with saline serum for 6-8 weeks depending on the size of the defect to be reconstructed. Generally it should be expanded 2-2,5 times the size of the defect.¹¹ The scalp is an ideal area for placing tissue expanders due to the thickness of the tissue and it being richly vascularized. Another of the principal advantages is the supply of tissue with a similar color and texture to that of the area to be reconstructed. Similarly, problems and inconveniences arise such as exposure and infection of the expander and the need for secondary reconstruction surgery. Generally alopecia is not produced but dryness or residual hyperpigmentation is left in the skin.

Local advancement and rotation flaps constitute the principal reconstruction method for small and medium sized defects. These flaps are harvested following the same basic principles of facial flaps except with the difference that these flaps need to be proportionally longer and wider due to the lack of elasticity of the scalp.¹² It is important to bear in mind several considerations at this level. Firstly, the design of the flap has to be done in such way that one of the principal vascular pedicles enters through the base of the flap (figs. 7 y 8) Secondly, the hairline should be taken into account and an attempt should be made to design the flap in such a way that the incisions are situated behind it so that better aesthetic results are achieved. Thirdly, the flaps should be harvested in a subgaleal plane with incisions into the galea in order to reduce the tension of the closure. Finally, various flaps may be needed in order to achieve complete reconstruction of the defect.

Ample and extensive defects of the scalp require the use of more sophisticated techniques for reconstruction such as microsurgical techniques.¹³ Microsurgical flaps supply a large amount of vascularized tissue for reconstructing large scalp defects (fig. 9). In spite of these flaps being reliable and predictable, poor aesthetic results are achieved as they have different texture, skin color and no hair.¹⁴ Nevertheless, they may be the only reconstructive option in cases in which there is extensive exposure of the cranium and in which other local and regional flaps cannot be used.

The greater omentum is a double layer of peritoneum that extends from the greater curvature of the stomach to its insertion into the transverse colon. The principal source of irrigation of the omentum is from the left and right gastroepiploic arteries, situated under the greater curvature of the stomach, which both depend of the celiac trunk. The right gastroepiploic artery is a branch of the gastroduodenal artery which, in turn, arises from the hepatic artery and the left gastroepiploic artery is a branch of the splenic artery. Both gastroepiploic arteries form a rich vascular network with multiple anastosmosis¹⁵ due to the four principal branches of this vascular plexus: accessory omental artery, right omental artery, middle omental artery and left omental artery. The middle omental artery eventually divides providing branches that form anastomosis with the left and right omental arteries.

Alday and Goldsmith¹⁶ describe 5 anatomical variants in a series of 246 dissections of corpses. They reported five different types of distribution and anastomosis of the vascular plexus:

a. Type 1. The middle omental artery divides at the bottom third of the omentum forming anastomosis with the left and right omental arteries (81.7%).

b. Type 2. The middle omental artery divides in the middle third of the omentum forming anastomosis with the terminal branches of the left and right omental arteries (11%).

c. Type 3. The middle omental artery divides in the middle third of the omentum into two or three branches (4.5%)

d. Type 4. Absence of middle omental artery which is substituted by various small omental branches (1.2%).

e. Type 5. The left omental artery does not join the left gastroepiploic artery in spite of the middle and right omental artery arising from the right gastroepiploic artery (1.6%).

These anatomical variants are important when harvesting the flap, depending on if we want to divide or elongate the omentum in order to adapt it to the defect that is to be reconstructed.

On the other hand there are considerable variations with regard to the length and diameter of the omentum. Das¹⁷ in a series of 200 corpses correlates the size of the omentum with the weight and size of the patient. Nevertheless, he reports that these parameters are very limited for predicting size, as situations such as peritonitis or previous abdominal surgery produce an important retraction of the omentum.

The vascular pedicle of the omentum free flap is made up of the right gastroepiploic artery and its two comitant veins, as it is larger in size than the left gastroepiploic artery and it covers a longer section along the greater curvature than the latter.18 The right gastroepiploic artery has a diameter of 1.5-3 mm while the left gastroepiploic artery has a diameter of 1.2-2.9 mm.^8,18

The omentum free flap has been widely used in reconstructive surgery of the head and neck as it has numerous advantages. It has on the one hand a vascular pedicle which is consistent in terms of size and location. It has a large pedicle that has the capacity for forming anastomosis with the left or right gastroepiploic vessels according to the size of the receptor vessels.⁸ On the other hand, the donor site is sufficiently away from the cervicofacial region so as to allow two teams to work simultaneously and thus reduce surgery time.^5,7 Finally the omentum flap is a very manageable flap which can be molded and folded in order to achieve adequate volume, and it can be adapted perfectly to the defect that has to be reconstructed.^5,6,8

The principal inconvenience is that in order to obtain this flap a medial laparotomy has to be performed and com plications can appear such as bridles and secondary intestinal obstruction caused by the formation of volvulus.¹⁹ As an alternative to this flap, and to avoid complications in the donor site, the free latissimus dorsi muscle flap with a skin graft cover has been used frequently in the reconstruction of this type of defect with good aesthetic results and minimum donor site morbidity.²⁰

Finally, it is important to report the degree of atrophy that can be experienced with this flap during the first months following surgery. Some authors such as Panje and Moran²¹ reported atrophy of approximately 20-50% in the three months following surgery. Nevertheless, Upton⁸ presented a small series of three cases with a 2 year following in which there was hardly any variation in the volume of the flap. In our case the patient did experience a small amount of atrophy in the flap although not to the extent of the percentages previously indicated.

To conclude we would like to stress the capacity of the greater omentum in the reconstruction of scalp defects that are extensive in length and in volume. It constitutes a reliable and predictable flap and, being easy to handle, it can be adapted perfectly to the defect. Nevertheless, the risk of a medial laparotomy has to be previously and seriously taken into account, as alternative flaps for reconstructing the same defect can be used with identical aesthetic and functional results.

References

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20. Gordon L, Buncke HJ, Alpert B. Free latissimus dorsi muscle flap with split-thickness skin graft cover: report of 16 cases. Plast Reconstr Surg 1982;70:173.        [ Links ]