Clinical Criteria for Selective Exploration of Orbital Floor in Zygomaticomaxillary Complex Fractures

Abstract

Purpose: Exposing the orbital floor requires a surgical procedure that has its own challenges. Despite the meticulous clinical examination followed by sophisticated imaging modalities, orbital floor defects associated with zygomaticomaxillary complex (ZMC) fractures may evade diagnosis and appropriate management. If surgeons can decide about the need for orbital floor exploration in patients with ZMC fracture, the chance of a postoperative eyelid deformity can be prevented. The aim of this article is to assess whether an association exists between the pattern of fracture line and the need for exploration of the orbital floor in ZMC fracture. Materials and Methods: A retrospective study of 94 patients with isolated, unilateral ZMC fractures who were treated at our unit by open reduction of the ZMC complex with internal orbital exploration from January 2016 to January 2018. The records of all patients were reviewed and specific data related to fracture pattern and orbital floor defect were registered and assessed. Results: Of the 94 cases with isolated, unilateral ZMC fractures, in 80 cases the fracture line propagated to the orbital floor, which required exploration but did not required any reconstruction and only the infraorbital rim was addressed; 14 of them required orbital floor reconstruction. Among the cases which required orbital floor reconstruction, the majority of the cases where those with fracture involving medial side of infraorbital foramen (n = 10) followed by lateral side (n = 3) and through the foramen (n = 0) and lastly bilateral side of the foramen (n = 1). Conclusion: The present study highlights the pattern of fracture line at the level of infraorbital rim can predict the need for orbital floor exploration while treating ZMC fractures for purpose of orbital floor reconstruction. Based on the results and a review of the records, authors strongly recommend the need for exploration of orbital floor when the fracture line passes medial to the infraorbital foramen.

Introduction

If surgeons can decide about the need for surgical exploration of orbital floor in zygomaticomaxillary complex (ZMC) fracture, the chance of a postoperative eyelid deformity can be prevented. Zygomaticomaxillary complex fractures, by definition, are almost always associated with fractures of the orbital floor. The magnitude of these injuries can vary from a linear crack to communition of the complete orbital floor.

However, there is no universal agreement among surgeons who prefer the exploration and reconstruction of the orbital floor routinely when operating a ZMC fracture, it is clear that not all ZMC fractures require internal orbital reconstruction. [1,2]

Exploring the orbital floor requires a surgical procedure that has been more frequently encountered with complications such as palpebral asymmetries, entropion, ectropion, and symblepharon. These can have disturbing psychologic and social implications for the patients. [3]

Some studies show that it is not always possible to detect the orbital floor fractures preoperatively and can only be diagnosed upon intraoperative exploration of the orbital floor following open reduction. [4] The big question, however, is how does one decides about the need for orbital floor exploration when a patient presents with a ZMC fracture?

Keeping in mind the intricate anatomy of the region, the primary aim of this study was to assess whether a clinical and anatomical association exists between the pattern of fracture line and the need for exploration of the orbital floor in ZMC fracture.

Materials and Methods

The prospective analyses of retrospective data of 227 patients with midface fractures reporting to the Department of Oral and Maxillofacial Surgery from January 2016 to January 2018 with established cases of ZMC fractures were involved in the study. A detailed clinical examination with ophthalmic consultation was carried out to assess visual acuity, ocular motility, pupils, and visual fields.

All the patients were subjected to conventional paranasal sinus (PNS) view and computed tomography (CT) scans with axial, coronal, and sagittal sections with 1 mm cuts with 3-dimensional reconstruction. Intraoperatively, after exposure of all the fracture fragments, the floor of the orbit was explored to assess the amount of bony discontinuity and to correlate ZMC fracture pattern with magnitude and extent orbital floor disruption. Based on clinical assessment of ZMC fracture pattern, the fracture lines were divided into 4 different classes in relation to infraorbital foramen as shown in Figure 1.

Patients with gross midface fractures with comminuted fractures of the fronto-naso-orbito-ethmoid fractures and pediatric fractures and patients having incomplete set of records were excluded from the study. Data for all the groups was compiled and analyzed by a single investigator using a Fischer exact test.

Results

Based on inclusion and exclusion criteria, 144 patients reported to the Department of Oral and Maxillofacial Surgery from January 2016 to January 2018 with established cases of ZMC fractures were included in our study.

A total of 144 fractures involving infraorbital rim associated with ZMC fractures were studied; 50 cases were excluded due to lack of appropriate information.

As depicted in

Table 1. Patients Demographical and Fracture Details Stratification.

Abbreviations: B/L, bilateral; F, female; RTA, road traffic accident; R, RT, right; L, LT, left.

, Of 94 cases, 82 (90%) patients were male and 12 (10%) were female with the ratio of 9:1. The most common etiology was road traffic accidents affecting 71 (75%) patients, followed by falls in 16 (17%) patients and assaults in 6 (6%) patients and industrial injury in 1 (1%) patient. In our study, we observed the highest incidence noted in the age group of 21 to 30 years (46 patients, 48.6%) followed by 16 patients being of 41 to 50 years age group comprising 17% of total patients, 15 (15.95%) patients were between 31 and 40 years, and 10 (8.5%) between below 20 years. The lowest incidence was noted above 50 years of age which comprised of 5.3%.

As depicted in

Table 2. Distribution of Fracture Line in Relation to Infraorbital Foramen and Relation to Orbital Floor Exploration and Reconstruction.

, of the 94 cases involving orbital floor fractures in ZMC fractures, 35 (37.2%) involved the medial side of the infraorbital rim, 32 (34%) involved the lateral side of the infraorbital rim, 21 (22.3%) involved the infraorbital foramen and 6 (6.3%) were seen bilateral to the infraorbital foramen. A statistically significant association was seen between site of fracture in relation to infraorbital rim and orbital floor involvement. (P = .008).

Size of defect measured in CT scan ranged from 4 to 12 mm with mean of 7 mm. The patients presented with preoperative symptoms of enophthalmos, periorbital edema, subconjunctival ecchymosis, and diplopia. All patients had a thorough pre-operative ophthalmologic examination that assessed the functions for visual acuity, pupillary reactivity, extraocular motility, examination of anterior and posterior segment, and infraorbital nerve sensation. Mean degree of enophthalmos in preoperative cases was 3.2 mm with highest being 4.5 mm and the lowest being 1.8 mm. The open reduction method of treatment was planned for ZMC fractures due to significant degree of displacement of the fractured segments in all cases.

As depicted in Table 2, in 80 cases the fracture line propagated to the orbital floor, which required exploration but did not required any reconstruction and only the infraorbital rim was addressed. Among the orbital floor exploration cases, 29 cases were those with fracture involving lateral side of infraorbital foramen (30.9%) followed by 25 cases passing from medial side (26.6%) and 21 cases through the foramen (22.3%) and lastly 5 cases involving the bilateral side of the foramen (5.3%).

As shown in

Table 3. Frequency of Reconstruction of Orbital Floor in Relation to Infraorbital Foramen.

, of the 94 cases, 14 cases required orbital floor reconstruction. Among the cases which required orbital floor reconstruction, the majority of the cases were those with fracture involving medial side of infraorbital foramen (n = 10, 10.6%) followed by lateral side (n = 3, 3.2%) and through the foramen (n = 0) and lastly bilateral side of the foramen (n = 1, 1.1%).

Postoperative evaluation revealed mild enophthalmos ranging from 0.5 to 1 mm in 9 patients which resolved over a follow-up period of 6 months. The symptoms resolved postoperatively over a follow-up period and none of the patient required any additional procedures for aesthetic deformity.

Discussion

Anatomy dictates the propagation of fracture lines to pass through the areas of least resistance. The orbital floor, medial to the infraorbital groove, is formed by the maxilla; the zygomatic bone forms the anterolateral aspect whereas minimal part in posterior region is contributed by palatine bone.

The medial wall and the floor constitute the weakest portions of the orbital region. The presence of infraorbital groove over the maxillary sinus results in thinning the orbital floor at its junction with the medial wall. Therefore, propagation of most fracture lines occurs around the infraorbital foramen between the posterior and medial part of the orbital floor.

Retrospective analysis of patients’ data by Krasadakis [4] confirmed that a considerable percentage (28 of the 82 or 34, 1%) of ZMC fractures were associated with orbital floor defects that had not been detected preoperatively and were only diagnosed upon intraoperative exploration of the orbital floor following open reduction.

Our observations have revealed that fracture pattern most commonly involving the infraorbital rim medial to the infraorbital foramen go on to involve the floor of the orbit. Highest incidence of fracture propagating from the infraorbital rim to the floor of the orbit was found medial to the infraorbital foramen comprising of 92.3%.

Floor of the orbit lateral to the infraorbital rim is composed of the zygoma and the orbital process of the palatine bone which forms a stronger resistance to propagation of the fractures. Only in 52.0% of cases the fracture propagated from the lateral portion of the rim lateral to the infraorbital foramen were found to involve the orbital floor. In 23.2% of fractures passing through the foramen involved the floor of the orbit. A total of 10.7% of fractures which occurred bilateral to the infraorbital foramen involved the floor of the orbit.

As per the retrospective analysis of patients data, 35 patients were found to have medially running fracture line from infraorbital foramen into the orbital floor of which 10 patients had an orbital floor defect more than 5 mm suggestive of high suspicion for orbital floor reconstruction in this kind of fracture pattern as compared to other fracture patterns which was significantly low.

The authors believe that present study is one of its kind which highlights an accurate assessment of the fracture site at the level of the infraorbital rim to predict the need for exploration of orbital floor. In the current state, authors were unable to find any existing articles on topic of clinical criteria for orbital floor exploration to provide a concise review and comparison with presented observations.

A key limitation of the study was the retrospective timeline and the fact that the implants included had been present for variable times. This was due to the availability of complete patient records of patients that included follow-up for at least 1 year from operative time. Availability of complete patient records and nature of interdisciplinary collaboration may have influenced the study. Therefore, this study could potentially help to form basis for future prospective studies for assessing data with larger sample size to clinically predict the need for orbital floor reconstruction.

Conclusion

To conclude the present study is one of its kind which highlight an accurate assessment of the fracture site at the level of the infraorbital rim which can predict the need for exploration of orbital floor. The authors strongly recommend the need for exploration of orbital floor when the pattern of fracture line passes medially to the infraorbital foramen as one of the additional preoperative variable along with other confounding variables such as mechanism of injury (high vs. low velocity), age of patients, size of fractures, concomitant facial injuries, and other preoperative symptoms (degree of enophthalmos, diplopia, etc). Treatment should be directed to sequentially treat ZMC fractures with the goal of doing as little surgery as is absolutely necessary to attain a satisfactory outcome with minimal postoperative morbidity.