Orbital floor fracture either isolated (about 40% of cases) or combined with zygomaticomaxillary fracture accounts for the majority of all traumas in the head and neck region. Surgery of orbital floor fracture is performed to free incarcerated or prolapsed orbital tissue that causes diplopia and to restore the anatomic skeletal size of the orbit. Nonresolving oculocardiac reflex and early enophthalmos are the indication of immediate surgical intervention 1.
There are great controversies regarding the time of surgical intervention, the approaches, and the grafting material to be used. Until now, there is no agreement regarding the time of intervention or grafting material. At the same time, the size of the orbital floor defect (based on the computed tomographic findings) that is indicated for surgical correction is still controversial 2,3.
Materials used for orbital graft can be divided into autologous, allogeneic, and alloplastic materials. Autogenous graft such as rib graft, iliac crest, or fascia can add to the patient morbidity with variable degree of resorption and increase the operative time. Nonresorbable alloplastic material such as teflon, Medpor may cause late complications such as infection and extrusion, as they remain permanent 4.
Bovine collagen (type I) has reasonable mechanical strength for membrane stabilization using either sutures or resorbable tacks with long resorption time (26–38 weeks), is easily trimmed and adapted, is cell occlusive, and allows nutrients transfer. In addition, it could be used as a single layer or be folded several times to fit into different situations 5.
However, the mechanical support provided by the collagen membrane is questionable especially in comminuted cases.
Aim of the study
The aim of the study was to evaluate whether the collagen membrane is suitable for small (<1 cm2) orbital floor defects.
Patients and methods
In this prospective randomized clinical trial, 20 patients presenting with orbital floor fracture (16 combined with zygomaticomaxillary complex fracture and four patients were with pure orbital floor fracture) were included. The majority of fracture cases (86%) were due to motor vehicle accident, 15 male patients and five female patients. The age ranged from 8 to 40 years, and five pediatric patients were included in the study.
We have used resorbable collagen membrane (Implant Direct Sybron Europe AG, Zurich, Switzerland) made from bovine type I collagen of 0.35 mm thickness and 2×3 cm in size.
All patients have been evaluated clinically and radiographically preoperatively and 6 months postoperatively. Patients with frontal, frontobasal, orbital roof, or medial wall fractures were excluded.
Clinical evaluation included inspection, palpation, and documentation of hypothesia or anesthesia by infraorbital nerve. Before inclusion to the study, fracture site and size were evaluated using computed tomographies. Field of vision, ocular mobility, exophthalmos, and enophthalmos were examined by ophthalmologist.
All patients were operated under general anesthesia within 10 days of trauma using a subciliary approach to access the orbital floor and to free incarcerated orbital tissues. Collagen membrane was then placed to reline the orbital floor (Fig. 1) before the suturing traction test was performed.
No intraoperative complications occurred. Slight diplopia occurred immediate postoperatively in one patient and disappeared after 6 months. Hypothesia in the area supplied by infraorbital nerve was reported in two patients. Neither infection nor dehiscence was reported in any treated patients. Ophthalmologically no enophthalmos or exophthalmos was noticed after 6 months (Fig. 2). Radiographic evaluation after 6 months showed evidence of new bone formation without soft tissue being prolapsed (Fig. 3).
Despite great advancement in grafting materials and surgical approaches, there is no ideal graft for orbital floor reconstruction 6,7. In fact, autogenous bone graft plays a major role in comminuted floor reconstruction and is considered as a gold standard. However, it carries many disadvantages and should be limited to comminuted cases. Another treatment option is alloplastic materials, which may be associated with late complications such as infection, as they remain permanent. In addition, it does not favor new bone formation 6,8.
Collagen membrane provides biologically compatible graft, which is highly available, pliable, and can resorb within 24 weeks. It could be used in pediatric population in combination with resorbable bone plate. Collagen membranes could be used as a single layer or be folded to fit into the defect 5,9.
With respect to physical support of the orbital content, it has been found that the weight of the orbital content is around 30 g, which represents minimal force in small-size defect (1 cm2) 10 where collagen membrane could be used safely; however, for larger size defects, the use of collagen membrane is questionable 11.
The ultimate strategy is to use each graft in selected patients, as there is no graft ideal for all patients of orbital floor reconstruction. The selection is influenced by many factors including graft availability, age of the patient, surgeon experience, size of the defect, associated injuries, and financial issues 7,12.
Our data suggest that collagen membranes are suitable for reconstruction of the defects in the orbital floor, which are less than 1 cm2. It provides smooth, pliable foundation for new bone formation at the fracture site. In pediatric population, it provides ideal solution in combination with resorbable bone plates.
Conflicts of interest
There are no conflicts of interest.
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