Artículo Clínico

Tissue expansion in the reconstruction of craniofacial defects
Expansión tisular en la reconstrucción de defectos craneofaciales

V. Escorial Hernández¹, A. Capote Moreno¹, R. González García¹, F.J. Rodríguez Campo²,
L. Naval Gías², F.J. Díaz González³

1 Médico Residente.
2 Médico Adjunto.
3 Jefe de Servicio.
Servicio de Cirugía Oral y Maxilofacial.
Hospital Universitario de La Princesa. Madrid, España.

Correspondencia:
Verónica Escorial Hernández
C/ Cea Bermúdez 68, 5º B
28003 Madrid, España.
E-mail: veronicaesc@hotmail.com

Introduction

The concept of tissue expansion was introduced in 1976 by Chedomir Radovan¹ in breast reconstruction surgery. At first there was great enthusiasm and it was soon applied in many areas. However, the large number of complications that arose and the dissatisfaction with results made if fall into disuse. Currently case selection, technique refinement, and the combination of other alternative surgery (local and regional flaps; free grafts, etc.) have made tissue expansion a useful instrument in reconstructive surgery of the head and neck.

Skin expanders are silicon prostheses connected to a valve system through which variable amounts of liquid are injected periodically. The patient has to be carefully selected, and made aware of, and agree to, at least two operations, periodic injections and the discomfort that can arise from aesthetic changes that originate on inflating the expander. The tissue to be expanded and the most adequate insertion site depend on the defect. The size and form of the expander should also suit the defect to be reconstructed. The diameter of the expander should be 2 to 3 times the width of the defect.⁴

Tissue expansion allows the repair of defects by means of the progressive stretching of the skin, which will provide a tissue of a similar color and texture with minimum damage to the donor site.^2,6 The results obtained are excellent from the aesthetic and functional point of view.

Material and method

This is a retrospective study of 9 patients (2 men and 7 women) treated with tissue expanders for the reconstruction of craniofacial defects over the last five years. A descriptive analysis is made of the series that also takes into account the results obtained according to different variables (surgical technique, localization of the defect, situation and size of the expander as well as the rhythm of expansion) together with the complications that arise which can influence the final result of the intervention.

Results

The mean age was 57.70 with ages ranging between 20 and 81 years. The [tissue expanders] were used in nearly 100% of the cases following tumor resection, with basal and squamous cell carcinoma of the skin being the most frequent diagnoses in 6 of the 9 patients (66.66%). The average size reached was 260 c.c. with an average rate of 13.55 c.c. in each session. The treatment was prolonged between 15 and 55 days (average length of time of expansion was 37.6 days). In three patients complications arose: in two removing the expander and bringing the surgery forward was necessary due to ulceration of the expanded tissue and crystallization of the liquid introduced. In a third patient the device was perforated, but the desired size had been reached and the surgery that had been programmed went ahead.

The final result was, nevertheless, satisfactory for the surgeon as well as for the patient in 100% of cases.

The patients' characteristics are summarized in table 1.

Discussion

The reconstruction of cutaneous defects using tissue expanders started in the 80s following Rodovan´s studies¹ in surgical reconstruction of the breast. They were applied rapidly in numerous other localizations, including the craniofacial area due to the positive results obtained. However, one should not forget that they are not exempt of complications^{4,6,7- 10} and that in some cases they should be used in conjunction with other reconstructive techniques.^3-4,6,10 In our experience a proper selection of cases and a refined surgical technique are vital for complications to be kept at a minimum, and for the aesthetic and functional result to be satisfactory.

The expansion produces a mechanical dilation phenomenon in the tissues, which associated with minor damage due to ischemiahypoxemia, permits obtaining a well-vascularized tissue. A capsule with rich vascularization is generated around the expander on coming into contact with healthy tissue.⁴ Examination of the epidermis reveals hyperplasia with no quantitative or qualitative alterations in the population of melanocyte, Merkel and Langerhans cells. The response of the dermis to expansion is more noticeable, principally in the reticular dermis, as it becomes thinner, peaking 6-12 weeks after expansion. The reestablishment of its normal thickness is slow and may never be normal. Adipose tissue does not tolerate expansion well and it becomes permanently thinner in most cases. New follicles of hair^2,5 are not formed.

The principles behind tissue expansion were first used in facial defects by Argenta et al. in 1983, following excision of vascular malformations.¹¹ Oncological surgery is the origin of the defects requiring reconstruction in nearly 100% of the cases in our series. The most frequent diagnosis is basal and squamous cell carcinoma of the skin. The most important causes leading to the use of expanders, as revealed by other studies are, in addition to tumor resection, burn defects and congenital malformations during childhood (hemangiomas, fissures, nevus melanocytes).^{4,6-7, 10-11}

The success of the reconstruction depends not only on very careful pre-surgical planning, but also on an adequate surgical technique and a correct use of the expander.

Tissue expansion permits the introduction of tissue that is of similar color, texture and consistency to that of the defect, while the aesthetic and functional changes that could be encountered using other types of reconstruction are reduced.^3,6 In addition, morbidity in the donor site is minimal, with only small scars that can be concealed with a good design technique. We should therefore choose this [technique] for large defects or for patients that have undergone multiple operations and for whom other types of reconstruction is not possible due to the excessive tension this would cause (Fig.1 and 2). Once the cases have been selected, surgery will be planned taking into account the expander shape, as well as the most appropriate position for it, depending on the localization of the defect and possible retractions. The appearance of ectropion of the lip and/or eyelid should be avoided where possible. The expander is put into place under general anesthesia and the tissue to be expanded is infiltrated with local anesthetics with vasoconstrictor agents. The insertion of the expander is done under healthy tissue, and an incision is made perpendicular to the transverse axis of the expander and at a certain distance from the region where it is to be placed (dehiscence of the suture is therefore avoided when the tension is increased on expansion), which will have to be wide enough to enable good visibility. The tissues are dissected until there is sufficient size to contain the device. The expander is introduced folded over and it is unfolded completely once in the subcutaneous pocket that has been created. Special care should be taken with the instruments used. We avoid using pincers with teeth so as not to pierce the expander, as experienced on one occasion. The valve system is left extracutaneously at a certain distance from the expander, so that inflation is easier and perforation on inflation is avoided, which is what occurred at first as it was fitted into the prosthesis itself. Other authors create a second subcutaneous pocket for storing the valve,⁴ which can lead to more complications should the valve fail, and a greater risk of infection. In the same surgical act we begin to fill it with different amounts of distilled water, depending on the individual case. Unlike other authors4 we do not use physiological serum as it may crystallize, as occurred it one case, making it necessary to remove the expander. Following surgery it is filled periodically with variable amount of distilled water. The amount depends on the size desired, the appearance of pain or discomfort in the patient and on the viability of the tissue expanded. Inflation should be performed carefully and, when injected, vascular compromise of the skin should be checked so as to avoid ulceration of the tissue (Fig.3).

The prophylactic administration of antibiotics can decrease the risk of infection of the expander.^3-4,6-10

On commencing treatment the patient should be made aware of and he should accept the discomfort and aesthetic alterations that appear during inflation, as well as the need for secondary surgery.^3,4

After obtaining the necessary tissue for covering the defect, the second surgical phase is carried out under general anesthesia, which includes the removal of the device (Fig.4) and the reconstruction of the defect with advancement and rotation flaps of the expanded tissue (Fig. 5 and 6).

In three of the nine patients (33.33%) complications arose, a similar percentage to that observed in other studies:^3,6-10 in two cases (ulceration of the expanded skin, crystallization of the inflated liquid) removing the expander and bringing the surgery forward was necessary. In another patient the expander was perforated but, as the required size had been achieved, the reconstruction envisaged could be carried out. Despite these complications, in 100% of cases the aesthetic and functional result was satisfactory for the patient himself as well as for the surgeon.

Conclusions

The reconstruction of craniofacial defects is a constant challenge for the maxillofacial surgeon. The use of tissue expanders permits the introduction of tissue of a similar color, consistency and texture to that lost, leading to very satisfactory aesthetic as well as functional results. They are also very useful for large defects and for patients with multiple interventions. Morbidity in the donor site is minimal and the scars remaining are small.

Nevertheless, we should not forget that this is a prolonged treatment that requires at least two operations and a close collaboration from the beginning between the surgeon and the patient. As with all surgical techniques it is not without its complications, and the surgeon should make an effort to minimize these with good case selection and a careful technique, and the use of materials that may lead to perforation should be avoided. The use of distilled water is advisable so that crystallization of the liquid added is prevented.

References

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