Periorbital Entrapment in a Minimally Displaced Medial Wall Fracture

Abstract

I experienced periorbital entrapment in a minimally displaced medial wall fracture. An 18-year male was hit in the left eye by a fist. He had decreased horizontal ocular motility with pain. Exophthalmometry of both eyes were same. Computed tomography (CT) demonstrated a minimally displaced medial wall fracture with herniation of orbital fat. Decreased horizontal ocular motility and pain persisted until the fifth post-trauma day. On exploration, entrapped soft tissue was found and dissected from the fractured site, but the bony displacement was minimal. After release, the forced duction test became normal and postoperative CT demonstrated reduced herniated orbital fat. In cases of a minimally displaced medial orbital wall fracture, if the patient feels pain while gazing horizontally, precise inspection of the CT scan is needed. If the pain persists for several days, despite the absence of diplopia, periorbital entrapment should be suspected and exploration can be considered.

Introduction

The incidence of trapdoor-type medial blowout fractures is extremely low compared with that of trapdoor-type floor fractures, and they are easily missed due to the lack of other prominent soft tissue injury signs. ¹ Although medial rectus muscle incarceration is rare in trapdoor fractures compared with inferior rectus muscle incarceration, it may cause significant morbidity if left untreated. ² I experienced periorbital entrapment in a minimally displaced medial wall fracture.

Case

An 18-year male was hit in the left eye by a fist in a fight. Upon examination, he had decreased horizontal ocular motility of the involved eye with pain. Exophthalmometry revealed the same degree of forward displacement in both eyes (od: 16 mm, os: 16 mm). Computed tomography (CT) demonstrated a minimally displaced left medial wall fracture with herniation of orbital fat (Figure 1, left).

Figure 1.

Preoperative (left column) and postoperative (right column) computed tomography scans. Left: A minimally displaced left medial wall fracture with herniation of orbital fat into the ethmoidal sinus was observed. Upper left: axial view, Lower left: coronal view. Right: the herniated orbital fat was reduced after the operation. Upper right: axial view, Lower right: coronal view.

Decreased horizontal ocular motility and pain persisted until the fifth post-trauma day, so we decided to operate. Through subciliary incision, orbital floor and medial wall were explored. On the medial wall, entrapped soft tissue was found and elevated from the fractured site. Since the bony displacement was minimal, medial wall was not reconstructed (Figure 2). After release, the forced duction test became normal (Figure 3).

Figure 2.

Intraoperative photograph taken just after the release of the entrapped periorbital tissue. The medial orbital wall is seen.

Figure 3.

Forced duction test just after the release of the entrapped periorbital tissue.

Postoperative CT demonstrated reduced herniated orbital fat (Figure 1, right). The pain on horizontal eyeball movement was relieved after recovery from anesthesia.

Discussion

In my previous study, in which we reviewed 14 628 CT scans, 5.3% (788 of the 14 628 cases) had an old medial wall fracture, although the patients had not experienced any facial trauma within 1 month. ³ The reason for the relatively high prevalence of this finding is thought to be that medial fractures are often undetected on conventional plain X-ray imaging.

Brannan et al reported 9 cases of isolated medial wall fracture with medial rectus muscle incarceration and suggested that this type of fracture may present with varying motility abnormalities, depending on the location and extent of the fracture, and that evidence of soft tissue trauma may be lacking. ⁴ In our case, periorbital tissue, including orbital fat, was entrapped instead of the medial rectus muscle.

For orbital floor fractures, surgical repair has been ideally recommended within 2 weeks when symptomatic diplopia is present along with a positive forced duction test and evidence of orbital soft tissue entrapment on CT, or in patients of large orbital floor fractures that may cause latent enophthalmos or hypo-ophthalmos. ^5,6 In the present case, CT showed a minimally displaced medial orbital wall fracture with a small amount of fat herniation into the ethmoidal sinus.

In cases of a minimally displaced medial orbital wall fracture, if the patient feels pain while gazing horizontally, precise inspection of the CT scan is needed. If the pain persists for several days, despite the absence of diplopia, periorbital entrapment should be suspected and exploration can be considered.