15.2 Etiology and Presentation

15.1Introduction

Successful management of volume loss within the orbit and periorbital region involves accurate diagnosis of the underlying cause, treatment of any ongoing contributory factors, followed by volume replacement. Traditional surgical methods of volume replacement, ranging from bone grafts, orbital or periorbital implants and autogenous soft-tissue grafts (e.g., dermis-fat) have been somewhat crude and di cult to titrate to the exact site and degree of volume loss in any given individual. In addition, morbidity from these procedures has been high, with a significant risk of complications such as implant extrusion, hemorrhage, or infection. The development of artificial soft-tissue fillers has revolutionized the management of orbitofacial volume loss, enabling a precise, titratable, reversible treatment to be applied. This has permitted more subtle volume deficits to be e ectively treated, expanding the potential role of volume replacement therapies from the treatment of grossly disfiguring pathology to that of subtle rejuvenation. Furthermore, the versatility of these soft-tissue fillers has resulted in their successful application to other periocular pathologies including lagophthalmos and eyelid malposition. As newer and improved soft-tissue fillers continue to emerge, we anticipate wider and increased use of these products within the field of oculoplastic surgery.

15.2Etiology and Presentation

15.2.1Etiology of Orbital Volume Loss

Orbital volume loss is caused by insu ciency, loss, or displacement of any of the orbital components including the bony skeleton, the globe and the intervening soft tissues [14]. Bony causes typically include trauma and orbital fractures, where displacement of parts of the bony skeleton causes enlargement of the orbit, leading to a relative deficiency of orbital contents. A similar e ect is

seen in silent-sinus syndrome where obstruction of the maxillary ostium leads to negative pressure in the maxillary sinus and bowing of the orbital floor towards the imploding sinus [8]. Other bony causes of orbital volume deficiency include bony agenesis, such as that of the sphenoid wing seen in association with neurofibromatosis 1 [43], or iatrogenic bone removal, as occurs with bony orbital decompression.

Damage, loss, or absence of the globe also leads to orbital volume deficiency. This includes phthisis, acquired anophthalmos from evisceration or enucleation, and congenital microphthalmos/anophthalmos. As the latter condition is associated with abnormal growth of the entire orbit, it tends not to present with the same features of orbital volume loss and will not be discussed further here.

Orbital volume deficiency can also arise due to softtissue changes resulting in contraction and atrophy. Contraction occurs as a result of orbital sclerosing inflammation which can either be specific, e.g., Wegeners granulomatosis [60], or idiopathic. Other causes include post-inflammatory or postsurgical fibrosis and scirrhous metastatic breast carcinoma [14]. Atrophy commonly a ects orbital fat and can develop following orbital inflammation, radiotherapy, surgery, trauma, or compression from orbital varices [14]. It can also be caused by idiopathic atrophic conditions,such as Parry-Romberg syndrome (Fig. 15.4c), a rare disorder characterized by progressive atrophy of the skin and soft-tissues over half of the face [7, 9]. Finally, orbital fat and soft-tissue atrophy most commonly occurs with age, leading to a secondary loss of orbital volume [17, 64]. Some of these causes of orbital volume loss are illustrated in Fig. 15.1.

15.2.2Etiology of Periorbital Volume Loss

The causes of periorbital volume loss are similar to those responsible for orbital volume loss, with the exception of globe pathology. Both bone and soft-tissue changes contribute, through displacement, surgical removal,

agenesis, or atrophy. Boney causes include facial trauma, resulting in zygomatico-maxillary displacement, iatrogenic bone removal during treatment for sinus carcinomas, and maxillary hypoplasia. The latter can be constitutional, syndromic (e.g. in association with Crouzon syndrome) or following radiotherapy.Recent advances in imaging techniques have also confirmed that a significant degree of maxillary bone resorption occurs with aging [49, 50].

Soft-tissue causes of periorbital volume loss are more common and include iatrogenic excision of periocular facial tumors, neurofibromas (Fig. 15.5e), vascular malformations or even excessive fat removal in blepharoplasty (Fig. 15.4e). Late temple volume loss following orbital surgery involving trauma in the region of the temporalis muscle is a well observed phenomenon. Rarely, Parry-Romberg syndrome and HIV-treatment-related

facial lipodystrophy [7, 9, 36] can also contribute to periorbital volume loss. However, the most common cause of periorbital volume loss currently presenting to oculoplastic surgeons is that of aging, where sof t-tissue atrophy leads to deflation of the skin and exposure of the underlying deeper periorbital anatomy (Fig. 15.1h) [17, 21, 22, 64, 50]. Some examples of periorbital volume loss are shown in Fig. 15.1.

15.2.3Features of Orbital Volume Loss

Patients presenting with orbital volume loss are primarily concerned with the cosmesis of the a ected orbit and the lack of symmetry with the other side. Typically, they exhibit the triad of relative enophthalmos, a hollow