In the setting of facial trauma with fracture of one or more orbital walls, clinically significant enophthalmos is a possible undesirable outcome after primary repair. In this article, the evaluation of patients presenting with acquired enophthalmos and the available minimally invasive and surgical management options are discussed.
Key points
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Enophthalmos is a potential sequela in trauma patients with orbital fractures; when necessary, primary surgical repair of the orbital fractures should be performed soon after the initial injury.
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Occasionally, patients present with persistent clinically significant enophthalmos after primary surgical repair.
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The therapeutic approach of persistent clinically significant enophthalmos after primary repair depends on the degree of orbital and facial asymmetry and the presence of residual soft tissue incarceration.
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Enophthalmic wedge implants are an effective and safe option for patients with persistent postoperative enophthalmos who require secondary surgical repair.
Posttraumatic enophthalmos
Enophthalmos, defined as the recession of the globe within the bony orbital compartment, is a common sequela of facial trauma involving orbital fractures. The condition develops secondary to displacement of a constant volume of orbital soft tissue in the setting of mechanical disruption and expansion of the bony structure of the orbit. Orbital fractures allow shifting of the orbital tissues into the adjacent sinuses. Fractures of the medial and inferior walls, the most common orbital fracture sites, lead to orbital fat prolapse into the ethmoid and maxillary sinuses, respectively. This posttraumatic migration of orbital soft tissue results in the globe shifting to a more posterior, and frequently more inferior, position. In their retrospective review of 119 cases of unilateral orbital fractures, He and colleagues found that combined medial-inferior wall fractures were responsible for most cases of posttraumatic enophthalmos.
Small amounts of enophthalmos (less than 3 mm) are undetectable and clinically insignificant. However, when patients sustain severe trauma involving larger fractures of the orbital walls, the resulting enophthalmos (3 mm or greater) can be quite obvious and aesthetically unacceptable ( Fig. 1 ). Furthermore, because the extraocular muscles are frequently also displaced by the shifting of orbital tissues, diplopia may occur. Surgical repair of the associated fractures is necessary in these instances to restore both structure and function.
Traditionally, autologous tissue implants were used for orbital reconstruction, including grafts from iliac, mandibular, maxillary, rib, and calvarial bone. More recently, the options for donor graft site have expanded to include more accessible tissue, such as nasal septum and anterior maxillary sinus wall. Although the autologous option offers seamless integration of the grafts into host tissue with low rates of extrusion, it also requires longer operating time and is associated with donor site morbidity. Over the past several years, there have been significant advancements in the manufacture of highly biocompatible alloplastic orbital implants. Surgeons now have many options when choosing an alloplastic implant, including resorbable and nonresorbable materials. Resorbable implants have the advantage of minimal inflammatory response and scarring at the expense of a decline in tensile strength over time (ie, polydioxanone). Nonresorbable implants have become very popular recently and include high-density porous polyethylene and titanium. These implants allow for integration of native tissue and offer good long-term stability. However, the presence of a permanent foreign body in the orbit confers a low risk of implant migration, exposure, extrusion, or infection. When surgeons choose implants appropriately and use sound surgical technique, orbital fracture repair has a very good success rate with regard to the correction of posttraumatic enophthalmos and the complication rates are low.
Posttraumatic enophthalmos
Enophthalmos, defined as the recession of the globe within the bony orbital compartment, is a common sequela of facial trauma involving orbital fractures. The condition develops secondary to displacement of a constant volume of orbital soft tissue in the setting of mechanical disruption and expansion of the bony structure of the orbit. Orbital fractures allow shifting of the orbital tissues into the adjacent sinuses. Fractures of the medial and inferior walls, the most common orbital fracture sites, lead to orbital fat prolapse into the ethmoid and maxillary sinuses, respectively. This posttraumatic migration of orbital soft tissue results in the globe shifting to a more posterior, and frequently more inferior, position. In their retrospective review of 119 cases of unilateral orbital fractures, He and colleagues found that combined medial-inferior wall fractures were responsible for most cases of posttraumatic enophthalmos.
Small amounts of enophthalmos (less than 3 mm) are undetectable and clinically insignificant. However, when patients sustain severe trauma involving larger fractures of the orbital walls, the resulting enophthalmos (3 mm or greater) can be quite obvious and aesthetically unacceptable ( Fig. 1 ). Furthermore, because the extraocular muscles are frequently also displaced by the shifting of orbital tissues, diplopia may occur. Surgical repair of the associated fractures is necessary in these instances to restore both structure and function.
Traditionally, autologous tissue implants were used for orbital reconstruction, including grafts from iliac, mandibular, maxillary, rib, and calvarial bone. More recently, the options for donor graft site have expanded to include more accessible tissue, such as nasal septum and anterior maxillary sinus wall. Although the autologous option offers seamless integration of the grafts into host tissue with low rates of extrusion, it also requires longer operating time and is associated with donor site morbidity. Over the past several years, there have been significant advancements in the manufacture of highly biocompatible alloplastic orbital implants. Surgeons now have many options when choosing an alloplastic implant, including resorbable and nonresorbable materials. Resorbable implants have the advantage of minimal inflammatory response and scarring at the expense of a decline in tensile strength over time (ie, polydioxanone). Nonresorbable implants have become very popular recently and include high-density porous polyethylene and titanium. These implants allow for integration of native tissue and offer good long-term stability. However, the presence of a permanent foreign body in the orbit confers a low risk of implant migration, exposure, extrusion, or infection. When surgeons choose implants appropriately and use sound surgical technique, orbital fracture repair has a very good success rate with regard to the correction of posttraumatic enophthalmos and the complication rates are low.
Persistent enophthalmos after primary orbital fracture repair
Nature of the Problem and Indications for Secondary Repair
In up to 10% of cases after primary repair of orbital fractures, patients present with persistent postoperative enophthalmos despite a seemingly successful reconstruction of the bony defect. This deformity may or may not be apparent in the immediate postoperative period. In some instances, enophthalmos may develop slowly over several months as postoperative edema resolves. Over this time, surrounding periorbital tissues heal, remodel, and may contract, and the orbital fat may also atrophy.
Factors that may be associated with persistent enophthalmos after primary fracture repair include a severe initial bony deformity, excessively delayed initial surgery, or inadequate initial repair. In particular, the timing of the primary repair has significant importance. Surgeons should aim to perform the primary repair soon after the traumatic event. Although most surgeons prefer to wait for some resolution in the normal posttraumatic edema, over a 1-year period following initial injury, several irreversible soft tissue changes take place within the orbit. These alterations may subsequently lead to permanent deformities in the underlying skeletal structure, and ultimately make repair extremely difficult. Imola and colleagues found that primary repair should ideally be performed at least within 3 to 6 months after acute injury for the best possibility of attaining restoration of facial form.
Indications for secondary repair of acquired clinically significant enophthalmos are similar to those for primary repair. Specifically, when enophthalmos is significant enough to cause aesthetically unacceptable facial asymmetry or when the deformity is accompanied by periorbital soft-tissue incarceration with functional compromise (ie, extraocular motility restriction and/or diplopia), secondary correction should be pursued. In terms of the timing of secondary repair, it is important to wait for resolution of postoperative edema after the primary repair to appreciate the true amount of residual enophthalmos.
Secondary Enophthalmos Repair: Management Options
Options for secondary repair of enophthalmos can generally be broken down into 2 broad categories: surgical and minimally invasive. Surgical correction involves orbital exploration and liberation of any residual soft tissue incarceration along with mechanical repositioning of the orbital contents via secondary implant placement. The minimally invasive option includes periocular injection of alloplastic materials with the goal of orbital volume augmentation.
For patients who require surgical management, surgeons may use any of the many autologous or alloplastic implants previously mentioned in this article. The authors’ preference for most cases of secondary clinically significant enophthalmos repair is to use the high-density porous polyethylene wedge implant. Similar to other high-density porous polyethylene implants, wedge implants have the advantage of good fibrovascular tissue integration. In addition, the “wedge” shape provides the bulk of volume augmentation posteriorly behind the globe with a thicker midsection and tapered anterior and posterior edges ( Fig. 2 ). When the thicker central portion is appropriately positioned inferior and posterior to the globe, it adds volume and exerts an anterosuperior force that helps correct both enophthalmos and hypoglobus. Traditionally, wedge implants have been used in anophthalmic patients with sunken socket syndrome for orbital volume augmentation. Recent studies have also shown them to be effective and safe in the primary correction of posttraumatic enophthalmos in seeing eyes. In the authors’ experience, enophthalmic wedge implants are very useful in secondary repairs as well.
Periocular injection of various biocompatible materials is an alternative, minimally invasive option for the secondary repair of clinically significant enophthalmos. The most popular injectable modalities include hydrophilic hydrogel pellet tissue self-expanders ( Fig. 3 ) and dermal filler injections, such as calcium hydroxylapatite spheres and hyaluronic acid. Although most published studies have investigated these materials as volume-enhancing treatments of anophthalmic sockets with enophthalmos and/or socket contracture, their utility can also be extrapolated to the secondary correction of posttraumatic enophthalmos in seeing eyes.
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