Vertical dystopia meaning

1 What is enophthalmos?

Enophthalmos can be defined as a retrodisplacement of the globe within the bony confines of the eye socket. It is characterized by increased depth and hollowing of the supratarsal fold, decreased anterior projection of the globe, shortening of the horizontal dimension of the palpebral fissure, pseudoptosis of the upper lid, and a decrease in the canthal angles. Enophthalmos becomes clinically obvious if the anterior globe projection is less than 12 mm or differs from the opposite side by 3 mm or more as measured by a Hertel exophthalmometer. The Hertel exophthalmometer uses the lateral orbital rim as a reference point. As such, if enophthalmos is associated with a displaced and healed orbitozygomatic complex [OZC] fracture, this method of assessment may not be valid due to the malposition of the lateral orbital wall.

Disorders of Eye Position

The most common reason for secondary revision is with respect to eye position.

Enophthalmos is defined as an abnormally retro-positioned globe with respect to the bony orbit. It is usually defined as a relative loss of projection to the contralateral globe. It is worth remembering that there may be anatomical differences of 2mm premorbidly [Figure 9-17].

Hypoglobus is an abnormal lowering of the globe usually due to a deficient anterior orbital floor.

Proptosis is an abnormally anteriorly positioned globe with respect to the bony orbit. This is common and reflects a relative reduction in size of the bony orbit relative to the soft tissue component. This is seen in depressed fractures of the orbital roof, medialized lateral orbital walls, or if there is increased soft tissue volume increase, such as in edema and hemorrhage. The vertical component is described as hyperglobus, which may be exaggerated by depression of the lower eyelid in the acute phase.

The phenomenon of differential vertical position of each orbit is defined as orbital dystopia [Figure 9-18].

Background

Persistent enophthalmos and diplopia following primary orbital reconstruction lead to unsatisfactory aesthetic and functional outcomes, respectively. Diplopia after surgical repair of orbital fractures has been reported in 8%52% of patients, while clinically significant enophthalmos has been reported in 27%.13 Large combined medial wall and orbital floor fractures tend to carry a higher risk of enophthalmos, particularly if the fracture compromised the inferonasal bony strut support. Secondary orbital reconstruction has traditionally been seen as extremely challenging, and keys to success are careful preoperative planning, appropriate imaging and identifying which patients are most likely to benefit from surgical treatment.4

Changes in orbital volume as small as 2.12.3mL have been shown to result in clinically significant globe malposition.5,6 Suboptimal reduction of orbital fractures in the acute setting results in increased orbital volume and in both secondary enophthalmos and diplopia. Symptoms may present in a delayed fashion, as a poorly fixed implant becomes displaced or changes in orbital anatomy after trauma are not considered properly. For instance, if the posterior bony orbit remodels following trauma, the retrobulbar volume may increase; the orbital fat is frequently repositioned posteriorly, further compromising support of the globe.7 Such anatomic reasons for globe malposition tend not to improve, and frequently worsen, over time following inadequate primary reconstruction.

Persistent diplopia following orbital fracture repair may be broadly categorized into either restrictive or paralytic etiologies. Poor primary reduction may lead to increased orbital volume and muscle impingement. Developing adhesions surrounding the implant and implant displacement may also restrict muscle movement. Such anatomic causes of symptoms result in restrictive strabismus and most often improve with revision surgery. Conversely, paralytic diplopia secondary to neuromuscular injury will not benefit from reoperation, although symptoms tend to improve over time with conservative management which depends upon nerve regeneration.

Enophthalmos

Posttraumatic enophthalmos is generally attributed to: [1] attenuation, contraction, or disruption of periorbital tissues and ligaments; or [2] enlargement of the bony orbit. The most common cause of enophthalmos is the lateral and inferior displacement of the body of the zygoma, resulting in increased orbital volume. The reconstruction of the zygoma must be realized in three dimensions to restore orbital volume, guided by realignment of the zygomaticosphenoidal sutures and infraorbital rims. Dulley etal. stress the importance of prevention with regard to the management of enophthalmos, noting a 72% incidence when treatment is delayed longer than 6 months compared to 20% when repair is performed within 2 weeks of injury.56 The importance of early intervention is further supported by the finding that 40% of patients undergoing delayed management required multiple surgical interventions.

If the recognition is acute, management occurs by reduction and fixation of fracture fragments restoring the normal orbital volume. If delayed, correction proceeds by periorbital release of cicatricial tissue, osteotomies and repositioning of nonanatomic bony segments. Rigid fixation and bone grafts may be utilized to resituate a laterally and inferiorly displaced zygomatic segment and cranial bone grafting or synthetic constructs may be utilized to reconstruct the orbital floor or wall support and elevate the globe. Delayed reconstruction is difficult and slight overcorrection of anterior globe prominence [but not vertical overcorrection of the globe] is generally recommended to account for inevitable relapse. Multiple procedures may be required to achieve an optimal result.37,38,5461

ETIOLOGY

Enophthalmos is posterior displacement of the eye. This is most commonly measured in relation to the outer edge of the orbit, the orbital rim, but it may also be assessed relative to the frontal and maxillary prominences or even the contralateral eye.

The term primary enophthalmos indicates a congenital problem for which the cause is unknown or unproved. Some degree of facial asymmetry is common, but congenital relative enophthalmos or orbital retrusion may occur with in utero maldevelopment [e.g. plagiocephaly or microphthalmos].

10 What are the causes of posttraumatic enophthalmos with and without vertical displacement of the globe?

Posttraumatic enophthalmos can result from any fracture that enlarges the orbital volume. Lateral and sometimes inferior displacement of the orbitozygomatic complex may be present. Isolated floor or medial orbital wall fractures with displacement can enlarge the orbit significantly. What is necessary for inferior displacement of the globe is injury to the periorbitum in addition to the bony injury, but this is the usual situation. An intact periorbita will hold the eye in place, but this occurrence is very rare. Vertical displacement of the globe may occur in extensive floor injuries of the blowout type. Most frequently these injuries are also associated with fracture and displacement of the orbitozygomatic complex.

Signs