Pure orbital blowout fractures reconstructed with autogenous bone grafts: functional and aesthetic outcomes

Abstract

The purpose of this study was to investigate the ophthalmic clinical findings following surgical reconstruction with autogenous bone grafts of pure blowout fractures. A retrospective review of 211 patients who underwent surgical repair of an orbital fracture between October 1996 and December 2013 was performed. Following data analysis, 60 patients who were followed up over a period of 1 year were included. A solitary floor fracture was present in 38 patients and a floor and a medial wall fracture in 22 patients. Comparing preoperative findings between these two groups, preoperative diplopia and enophthalmos were almost twice as frequent in the group with additional medial wall fractures: diplopia 8% and 14% and enophthalmos 18% and 55%, respectively. One year following surgery there was no diplopia present in either group. In the solitary floor fracture group, 3% still had enophthalmos. It can be concluded that at 1 year following the repair of pure orbital floor fractures using autogenous bone, good functional and aesthetic results can be obtained. In the group with both floor and medial wall fractures, no enophthalmos was found when both walls were reconstructed. When the medial wall was left unoperated, 29% of patients still suffered from enophthalmos after 1 year.

Orbital floor fractures are a relatively common result of facial injuries. Most occur as a result of falls, traffic accidents, sports accidence, violence, and work-related accidents.

The orbit consists of seven bones of the cranial and facial skeleton: the frontal, zygomatic, sphenoid, ethmoid, lacrimal, maxilla, and palatine bones. The thickness of the orbital bones varies; the rims are relatively thick, whereas the walls are relatively thin. Consequently, the orbital walls are more likely to fracture at a lower impact of trauma than the orbital rims. However, the point of impact also contributes to the pattern of fracture. Several patterns of fracture are defined: internal orbital (blow-out or blow-in), naso-orbito-ethmoid, and orbital-zygomatic. Facial trauma can cause one of these patterns or a combination of them.

The criteria for surgical repair of the orbital wall fracture are patient-specific. The decision regarding surgery must be based upon the symptoms of the patient, clinical findings, and informed consent in relation to the risks and benefits of a surgical intervention. Muscle entrapment, possibly associated with the presence of the oculocardiac reflex, indicates the need for immediate surgical release. Generally accepted absolute indications for surgery are persistent diplopia after the initial oedema has resolved, clinically disturbing enophthalmos (>2 mm), and vertical dystopia. Relative indications are a defect size larger than 50% of the wall and hypoesthesia of the cheek.

The timing of surgery is controversial. Some authors advocate early intervention (surgery within 2 weeks), whereas others follow a more conservative approach.

Several types of material can be used to repair the defect, for example autogenous bone grafts, polydioxanone (PDS) sheets, and titanium. There is no consensus regarding the optimal material. The choice of material is based mainly on surgeon preference, but the age of the patient and the size, location, and complexity of the fracture need to be taken into account. Autogenous bone grafts have been regarded as the gold standard to which other biomaterials are compared when repairing orbital floor fractures. Multiple harvest sites are available: iliac bone, rib bone, and calvarial bone. The biocompatibility, osteoconductive, and osteoinductive characteristics of bone grafts make them favourable over alloplasts. A disadvantage of using autogenous bone is the required donor site and the related morbidity, however the morbidity is temporary. Furthermore, graft resorption can occur, which could theoretically lead to late enophthalmos.

The aim of this study was to report the ophthalmic outcomes of pure blowout fractures following reconstruction with autogenous bone grafts at the 1-year follow-up. Only autogenous bone reconstructions were chosen in order to avoid bias resulting from the use of different materials. Results related to donor site morbidity have been published previously by this study group and will therefore not be discussed within this paper.

Materials and methods

The records of patients who underwent the surgical repair of orbital fractures at the authors’ institution between October 1996 and December 2013 were reviewed. Only patients, adults and children, who underwent primary surgical correction of pure blowout fractures with the use of autogenous bone were included. Fractures with involvement of the zygoma or naso-orbito-ethmoid complex were excluded. Patients with a solitary orbital floor fracture or a combination of floor and medial wall fractures were included. The groups were analyzed as a whole and separately to avoid possible bias. Surgery was performed by various surgeons, but the majority of procedures were performed by two surgeons. The need for surgery at the study institution is based upon the presence of persisting diplopia and enophthalmos, rather than on findings on a computed tomography scan.

Patients were followed up for 1 year; those with incomplete data were excluded. The following data were collected: basic demographics, date and aetiology of the trauma, affected eye, date and type of orbital reconstruction, and secondary procedures if performed.

Ophthalmic data collected included pre- and postoperative impairment of eye motility, subjective (clinically relevant and irrelevant) diplopia, exophthalmos, enophthalmos, hypoesthesia, hyperesthesia, and tear duct problems. The smooth pursuit of eye movement was used to determine the presence of impairment of eye motility. Enophthalmos and exophthalmos relative to the opposite side were determined using a Hertel exophthalmometer, measuring the difference between the anterior corneal surface and the lateral orbital rim. A difference of more than 2 mm between the two eyes is used to define clinically relevant enophthalmos or exophthalmos. Diplopia was assessed using the Bahn and Gorman diplopia score ( Table 1 ). Diplopia grades 3 and 4 were considered as clinically impeding diplopia, since these grades of diplopia interfere with normal daily activities.

Table 1
Bahn and Gorman diplopia score.
Grade of diplopia
1 Intermittent diplopia This is present only when the patient is fatigued
2 Inconstant diplopia This is present only on lateral or upward gaze
3 Constant diplopia This is present on straight and level gaze and is correctable with prisms
4 Constant diplopia This is present on straight and level gaze but is not correctable with prisms

In the case of a patient undergoing strabismus surgery, this was considered an endpoint of follow-up; consultations following strabismus surgery were not included in the evaluation as these would include a bias.

The follow-up assessments were divided into the following subgroups: preoperative (last consultation before surgery), 0 to 3 weeks postoperative, 3 to 6 weeks postoperative, 6 weeks to 6 months postoperative, and 6 months to 1 year postoperative. If a patient did not attend a consultation in one of the defined subgroups, this patient was left out of the analysis in that subgroup. When a patient received more than one consultation in one of the defined subgroups, the last consultation in the subgroup was used.

The time between the occurrence of the fracture and the surgical repair was calculated. The duration of follow-up was calculated from the time point of the first treatment to the date of last follow-up. The changes in outcome following surgery were analyzed.

The presence of clinically significant diplopia and enophthalmos at 1 year postoperative was compared between the groups of patients with and without the involvement of the medial wall using Pearson’s χ 2 test (Fisher’s exact test was used when appropriate). A P -value of less than 0.05 was considered significant. Data were analyzed using IBM SPSS Statistics for Windows, version 21.0 (IBM Corp., Armonk, NY, USA).

Results

Study population

During the time frame of the study, 211 patients underwent surgical repair of an orbital fracture at the authors’ institution. Primary surgery in another hospital was noted in 38 patients, as the study hospital serves as a tertiary facility within the Netherlands for orbital reconstruction surgery; these patients were excluded. Eighty-six patients were excluded as they had impure orbital fractures with an additional diagnosis of a zygoma or naso-orbito-ethmoid fracture. Alloplastic materials were used for the reconstruction in 25 patients, thus these patients were excluded. Two patients did not attend postoperative consultations and were excluded. This resulted in a total of 60 patients for analysis: 38 (63%) had solitary floor fractures and 22 (37%) suffered from both floor and medial wall fractures; 42 were male (70%) and 18 were female (30%). The mean age of the patients at the time of the orbital trauma was 38 years (standard deviation (SD) 15 years, range 15–80 years).

Aetiology of fractures

The most common cause of orbital wall fractures was violence (47%), followed by falls (22%), traffic accidents (12%), sports accidents (10%), work-related accidents (3%), and fireworks (3%). The cause of the orbital floor fracture had another aetiology in 3% of cases.

Surgery and follow-up

The floor was reconstructed in all patients. The medial wall was also restored in five of the 22 patients in whom the medial wall was involved in the fracture (8% of all patients). All patients received autogenous bone grafts harvested from the iliac crest.

Three patients (5%) underwent secondary surgery in order to correct persistent enophthalmos. In one of these patients the floor was reconstructed with alloplastic material during the second surgery; following this surgery the enophthalmos resolved. In the other two patients the floor was reconstructed with autogenous bone grafts; however enophthalmos persisted in these patients.

The mean time between the trauma and orbital floor reconstruction was 16 weeks (SD 22 weeks, range 0–98 weeks).

The average duration of follow-up after surgery was 10 months (SD 10 months, range 0–71 months). All patients attended consultations with the maxillofacial surgeon before and after surgery. Not every patient was seen at each follow-up point: 60 patients were seen preoperatively, 54 patients at 0 to 3 weeks postoperatively, 28 patients at 3 to 6 weeks postoperatively, 37 patients at 6 weeks to 6 months postoperatively, and 54 patients at 6 months to 1 year postoperatively.

Ophthalmic findings

Figure 1 shows the clinical findings pre- and post-surgery: decreases in impairment of eye motility, clinically relevant diplopia, enophthalmos, and hypoesthesia were found following surgical repair of the orbital floor.

Fig. 1
Clinical findings pre- and post-surgery. The vertical dotted line indicates the moment of surgery. The numbers of patients at each follow-up point can be found in the Results section.

As shown in Fig. 2 , the total percentage of patients with diplopia decreased from 65% preoperatively to 57% within 3 weeks after surgery. Preoperatively, 10% of the patients suffered from clinically relevant diplopia; within 3 weeks after surgery this had decreased to 6%, and at 6 weeks after the surgical repair this diplopia had resolved in all patients. Nevertheless, at 1 year following the surgical repair, 15% of patients still reported diplopia: this was diplopia grade 2 in 88% of these patients and diplopia grade 1 in the remaining 12%. None of the patients needed strabismus surgery.

Fig. 2
Graded diplopia pre- and post-surgery. The vertical dotted line indicates the moment of surgery. The numbers of patients at each follow-up point can be found in the Results section.

Enophthalmos was identified in 32% of the patients following trauma. Surgery resulted in a decrease of this percentage to 13%, with a further decrease to 11% at follow-up 6 months to 1 year postoperative. There were no cases of exophthalmos.

Infraorbital nerve hypoesthesia was observed in 28% of the patients before surgery and this percentage increased after surgery to 44% within 3 weeks postoperative. In the first year of follow-up, the percentage of patients with hypoesthesia decreased by 24% to 20%.

Hyperesthesia was present in two patients before surgery, but after 6 months of follow-up, none of the patients reported this condition. No patients suffered from tear duct problems either preoperatively or postoperatively.

Involvement of the medial wall

The medial wall was involved in 22 patients (37%). Not every patient was seen at each follow-up point; all were seen preoperatively, 19 were seen at 0 to 3 weeks postoperatively, seven at 3 to 6 weeks postoperatively, 15 at 6 weeks to 6 months postoperatively, and 20 at 6 months to 1 year postoperatively.

Clinically significant diplopia was present preoperatively in 14% of the patients in this group. Directly postoperatively, 11% of the patients still suffered from diplopia; at 6 weeks following surgery this percentage had diminished to 0%. Preoperatively, 55% of the patients with medial wall involvement suffered from enophthalmos, compared with 18% of the patients with a solitary orbital floor fracture. Within 3 weeks following surgery this percentage had decreased to 21%. At 1 year postoperative, 25% of all patients with a medial wall and floor fracture still presented with enophthalmos.

Within the group of patients with involvement of the medial wall, those patients in whom the medial wall was reconstructed together with the floor were compared to those who underwent only restoration of the orbital floor. The results are presented in Figs 3 and 4 . Only five of the 22 patients underwent surgical correction of both the orbital floor and medial wall.

Jan 16, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Pure orbital blowout fractures reconstructed with autogenous bone grafts: functional and aesthetic outcomes
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