ARTÍCULO CLÍNICO

 

Tiered skull graft for the management of post-traumatic enophthalmos and dystopia

Injerto escalonado de calota para manejo de enoftalmos y distopia postraumática

 

 

O.A. Vega Lagos¹, J.E. Abril Rodríguez², L.F. Peñuela Balaguera³, V.G. Páramo Jiménez⁴

1 Cirujano Oral y Maxilofacial
2 Residente IV año Cirugía Oral y Maxilofacial
3 Residente III año Cirugía Oral y Maxilofacial
4 Residente II año Cirugía Oral y Maxilofacial
Hospital Central de la Policía Nacional. Servicio de Cirugía Oral y Maxilofacial. Bogotá, D.C. Colombia.

Dirección para correspondencia

 

 

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ABSTRACT

Almost 90%¹ of traumatic injuries to the craniofacial massif involve the eye sockets, and a large proportion of these injuries generate sequelae, such as post-traumatic enophthalmos and dystopia.
The literature contains numerous references to surgical techniques for the correction of these sequelae and diverse materials for orbital reconstruction after trauma. However, few of them have been designed to restore the original anatomy of the orbital floor. For that reason, it is important to develop a simple and effective technique for correcting orbital damage. The present article describes the use of a new surgical technique for the management of the sequelae mentioned using a tiered skull graft on the floor of the orbit. It is an excellent option for graft placement because of its low resorption rate and minimal adverse reactions.
Patients. Four patients (1 woman, 3 men), average age 23 years (range 17-27 years) and history of facial trauma with orbital involvement were treated between 2004 and 2007 at the Hospital Central de la Policía Nacional and Hospital El Tunal (Bogotá, Colombia). All of them authorized the procedure by signing an informed consent form. The tiered graft technique was used for the post-traumatic correction of enophthalmos and dystopia. Results with a follow-up time of 11 to 42 weeks are reported.
Results. All the patients exhibited a reduction in the eye socket and symmetrical projection of the eyeball in anteroposterior and vertical direction, as well as complete improvement of the diplopia after the tiered skull graft was used to repair the orbital floor.
Conclusion. The technique is simple and inexpensive, with minimal morbidity and predictable and satisfactory results in the short and intermediate term.

Key words: Blow out; Enophthalmos; Diplopia; Dystopia; Cranium.

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RESUMEN

Casi un 90%¹ de los traumatismos del macizo craneofacial involucran las órbitas, y un alto porcentaje de los mismos generan secuelas como son el enoftalmos y la distopia postraumáticos.
Existen en la literatura numerosas referencias de técnicas quirúrgicas para corrección de dichas secuelas y diversos materiales para la reconstrucción orbitaria posterior al trauma, pero pocas de ellas se han encaminado a devolver la anatomía original al suelo orbitario, por tal razón se considera perentorio desarrollar una técnica sencilla y eficaz para la corrección de los defectos antes descritos. El presente artículo refiere la utilización de una nueva técnica quirúrgica para el manejo de las secuelas ya mencionadas usando un injerto escalonado de calota en el suelo de la órbita, dado que este último es una excelente opción para la colocación de injertos, debido a su baja tasa de reabsorción y mínimas reacciones adversas.
Pacientes. Cuatro pacientes (1 mujer, 3 hombres) con un promedio de edad de 23 años (rango entre 17 y 27 años) con antecedente de trauma facial y compromiso de la órbita, que fueron tratados entre 2004 y 2007, en el Hospital Central de la Policía Nacional y Hospital El Tunal (Bogotá, Colombia), previa autorización mediante firma de consentimiento informado. En ellos se utilizó la técnica de injerto escalonado de calota para corrección de enoftalmos y distopia postraumática. Se describen resultados con un tiempo de seguimiento entre 11 y 42 semanas.
Resultados. En todos los pacientes se observó disminución del continente orbitario y proyección simétrica del globo ocular en sentido antero-posterior y vertical, así como también mejoría completa de la diplopía, luego de la colocación del injerto escalonado de calota en el suelo orbitario.
Conclusión. Se trata de una técnica sencilla, de bajo costo, mínima morbilidad, con resultados predecibles y satisfactorios a corto y medio plazo.

Palabras clave: Blow out; Enoftalmos; Diplopía; Distopia; calota.

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Introduction

According to epidemiologic data, the orbit is involved in 89% of craniofacial injuries. In 71% of orbital injuries, the eyeball does not experience any injury or functional alteration. In civil life, 80% of traumatic injuries are originated by traffic accidents (motorcycles and cars) and the remaining 20% by assault, firearms, and home accidents.¹ When orbital trauma occurs, the sites most frequently affected, in decreasing order, are: orbital floor, 58%; lateral wall, 32%; medial wall, 24%; orbital rim, 11%; and roof, 3%.² Pearl in 1992 affirmed that 50% of patients with blow-out fractures present associated medial wall fractures.³ Converse and Smith, in 1959, reported that when comminuted malar and orbital floor fractures occur, the most frequent complications are enophthalmos and diplopia.⁴

Throughout history, different classifications of orbital fractures have been made, but it was Lang, in 1889, who specifically referred to blow-out fractures as a clinical entity.⁵ Nonetheless, the deepest definition was given by Converse and Smith in 1959.⁴ On their part, authors like Rene LeFort, in 1901, and Pfeiffer, in 1943, described the pathophysiology of this type of fractures.⁶

Recent scientific literature has focused on describing the best surgical approach and the best material for the reconstruction of the lost tissue. However, few authors have conceived their studies to return the morphology of the orbital floor that was lost after the trauma.^7-9

As the orbital floor is a bone structure with a complex morphology that has a length from the free orbital rim to the apex of 40 to 45 mm, in which the part anterior to the equator of the eyeball is concave and the part posterior to the equator is convex,¹⁰ it is not difficult to suspect that the material that is used for its reconstruction not only should be biocompatible but have a cost favorable to the patient and/or health services, and restore the original anatomy.

The fact that the diameter of the eyeball is approximately 25 mm and that the distance of the corneal portion from the orbital rim is 3 to 5 mm should be taken into account.¹¹ For that reason and considering the length of the orbital floor, the equator of the eyeball should be 10 to 11 mm from the lower free rim in its central part.

Assuming the configuration described above, a tiered skull graft was designed, which was used in four patients for the delayed treatment of post-traumatic sequelae of enophthalmos and dystopia.

 

Surgical technique

This technique was developed in four patients, in which the approach was performed in the scalp, in the parietal zone contralateral to the dominant cerebral hemisphere. The graft was obtained from the external table of the skull. It was obtained in a simple and practical way through a 5-cm linear incision in the scalp and dissection by planes to the bone, controlling bleeding. The graft was prepared with a tapered surgical burr 703 with a base 35 mm long in anteroposterior direction and a mean lateral length according to each case. The graft was raised with chisels, carefully conserving the internal cortex, and a smaller segment was placed on the larger fragment, which corresponds to the retroequatorial zone of the eyeball. It had an anteroposterior length of approximately 15 mm and a total height of 4 mm. Fixation was performed with two screws of the 1.5 system with a length of 5 to 7 mm (Fig. 1). The object of preparing the graft this way is to elevate and project the eyeball. In addition, the protocol of addition of plateletrich plasma (PRP) was applied.

After the preparation of the graft, it was fixed to the infraorbital rim by means of system 1.5 plates.

 

Clinical cases

Case 1

A 17-year-old woman who suffered a traffic accident on 25 September 2004 with a panfacial fracture. Open reduction and internal fixation of the fractures was performed 1 month after trauma due to the neurological condition of the patient. Postoperative sequelae: left enophthalmos, dystopia, and epiphora (Fig. 2). At 20 months of the intervention, the post-traumatic enophthalmos and dystopia were corrected simultaneously using a tiered skull graft on the floor of the orbit (Figs. 3, 4, 5 and 6). In both the immediate postoperative evaluation and at 42 postoperative weeks, correction of the enophthalmos and dystopia was demonstrated (Fig. 7).

Case 2

A 23-year-old man who presented right enophthalmos, diplopia, and dystopia and a right blow-out fracture after a traffic accident. (Fig. 8). These sequelae were corrected by applying a tiered skull graft to the floor of the right orbit, 11 months after the accident via an infraorbital approach through a previous scar. Platelet-rich plasma gel was added (Fig. 9). In the postoperative period and at 16 weeks, more symmetrical pupil axes and an important improvement in the projection of the right eyeball were observed, especially in the post-traumatic diplopia.

Case 3

A 27-year-old man with sequelae of blunt trauma to the left side of the face and untreated blow-out fracture. As a consequence, the patient presented left enophthalmos, dystopia, and diplopia (Fig. 10, Fig. 11). Eighteen months after the injury, these sequelae were corrected by applying a tiered skull graft to the orbital floor through a left transconjunctival approach (Fig. 12). In the postoperative evaluation, evident aesthetic and functional improvement of the conditions described was observed (Fig. 13).

Case 4

A 27-year-old man who suffered facial and cranioencephalic trauma produced by a traffic accident with a motorcycle. He was sent by the ophthalmology department of the Hospital Central de La Policía for evaluation and treatment of right enophthalmos. The physical examination also revealed incomplete paresis of the right III cranial nerve and major diplopia (Fig. 14). At 14 months of the accident, the post-traumatic enophthalmos was corrected by means of a tiered skull graft on the right orbital floor with the addition of platelet-rich plasma gel. In the immediate postoperative period, the anteroposterior projection of the eyeball was better and the patient referred improvement of the diplopia. The improvement in the anterosuperior projection of the right eyeball was evident. These results remained stable at 16 weeks of postoperative follow-up (Fig. 15).

 

Results

A total of four patients, average age 23 years (range 17- 27 years), with a history of facial trauma that affected the orbit were treated between 2004 and 2007 at the Hospital Central de la Policía Nacional and Hospital El Tunal (Bogotá, Colombia). The tiered skull graft technique was used for post-traumatic correction of enophthalmos and dystopia (Table 1).

All the patients exhibited a reduction of the eye socket and symmetrical projection of the eyeball in anteroposterior and vertical direction, as well as complete improvement of the diplopia after a tiered skull graft of the orbital floor.

 

Discussion

Facial trauma is a constant among cases of maxillofacial surgery in our setting. For this reason, it is necessary to be familiar with the proper management of fractures that affect the craniofacial massif in order to prevent postoperative sequelae in the patient. One of the most frequent conditions produced by facial fractures is enophthalmos. The main cause is the inadequate reduction of malar fracture, which originates an imbalance between the volume of the eye socket and the eyeball, which produces posterior and, sometimes, inferior displacement of the eyeball.⁸

For the proper management of orbital fractures, it is necessary to understand their pathophysiology and how the forces are transmitted through the walls of the eye socket or the eyeball itself. It also should be remembered that the medial orbital wall and orbital floor are the points of least resistance and the areas most likely to fracture. Grant notes that changes of 10% in the orbital volume generate variations in eyeball position.³ Two basic types of blow-out fracture are observed: posterior extension to the eyeball axis due to fracture of the orbital floor and concomitant fracture of the medial wall.⁸

In most of the techniques used to correct post-traumatic orbital sequelae, one of the main disadvantages is that it does not restore proper orbital anatomy and the eyeball does not recover its original position, resulting in enophthalmos and dystopia. Considering that the orbital floor has an anterior concavity and posterior convexity that keep the eyeball positioned, we report the technique of tiered skull graft for regenerating the lost anatomy and restoring the forward and upward projection of the eyeball. As this is an autologous graft, the resorption rate is minimal and the morbidity of the donor site is not significant.

Several techniques are described in the literature for the correction of blow-out fractures and their sequelae, including endoscopic correction techniques and correction with alloplastic materials and autologous grafts, among others. Autologous grafts have the highest success rate due to less resorption, less possibility of rejection, and lower costs. Zins and Whitaker, in 1983, claim that bone grafts of intramembranous origin have a lower rate of resorption than endochondral bone grafts. Zins, in 1984, added that this condition is due to the early revascularization phenomena that the intramembranous graft presents and its microarchitecture. Bone of intramembranous origin has a thin cortical layers and a denser layer of cancellous bone than endochondral bone. These differences are the basis of the differential resorption of the grafts. Ozaki and Buchman, in 1998, reported that cortical grafts are reabsorbed less than cancellous bone grafts and attribute this finding to the bone architecture rather than its embryologic origin.

With respect to donor site morbidity, Krauss and Gatot,¹² in 2001, evaluate the efficacy of the repair of orbital floor defects with nasoseptal cartilage, encountering a high success rate with minimum donor site morbidity. Castellani, in 2002, repaired defects in the orbital floor with cartilage from the ear, achieving more than 90% success con minimal morbidity.¹³

Another material used is preformed titanium mesh, which has the advantage of restoring orbital anatomy in almost all its details. In 2006, Schon and Metzger¹⁴ achieved 100% success in the repair of orbital floor defects, with additional advantages like ease of placement, shorter surgical time, greater precision, and less invasiveness. With the tiered skull graft, we obtained the same benefits without having to place foreign bodies in direct relation with the eyeball, which entails risk.

Muñoz – Guerra et al., in 2000, enumerate the disadvantages of autogenous and alloplastic materials. With respect to autogenous materials, they mention unpredictable resorption rate, implant mobility, donor site morbidity, and extreme difficulty in recovering the lost orbital anatomy. With regard to alloplastic materials, they note infection, implant extrusion, residual tissue reaction, and diplopia.¹⁵

 

Conclusions

The technique presented here for the reconstruction of the orbital floor is simple, easily executed, and has predictable results. The procedure is performed completely with autologous bone, which reduces costs.

More cases and long-term follow-up are needed to obtain statistically significant results.

 

 

Dirección para correspondencia:
Dr. Omar Alejandro Vega
Apartado aéreo 52309
Bogotá, D.C. Colombia
E-mail: omalvega@yahoo.com

Recibido: 20.6.07
Aceptado: 27.11.08

 

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