Orbital and Intracranial Emphysema Causing Orbital Compartment Syndrome: A Rare Case Report and Literature Review

Abstract

A case of 50-year-old male who presented with orbital compartment syndrome as a sequela of mid facial trauma, and literature review. Orbital compartment syndrome (OCS) is one of the potentially sight threatening emergencies encountered in clinical practice. Acute rise in pressure within the confined orbital cavity compromises the blood flow to retina and optic nerve leading to irreparable vision loss. Air entrapped in the orbital cavity leading to orbital compartment syndrome has been rarely reported. A brief literature search for the term orbital emphysema in PubMed yielded 352 articles out of which 280 articles were identified after screening for appropriate titles and case reports. A total of 138 patients were reported in the literature with severe orbital emphysema. Acute orbital compartment syndrome needs to be recognized and addressed on an emergency basis to achieve decompression so as to prevent an irreversible vison loss. Watchful eyes, an accurate diagnosis and timely surgical intervention could potentially reverse permanent damage to the optic nerve.

Introduction

Orbital compartment syndrome (OCS) following repair of a fracture zygoma was initially described by Gordon and McCrae in 1950 [1]. Acutely increased intraorbital pressure beyond the systemic pressure shall lead to increased intra-compartment pressure which leads to hypoperfusion and subsequent ischemia affecting the optic nerve and retinal function which may lead to irreversible loss of vision [2].

Retrobulbar haemorrhage secondary to orbital or facial trauma has been described as the most common cause of OCS followed less commonly by ophthalmic surgical trauma, peribulbar or retrobulbar injections, orbital emphysema and non-ophthalmic procedures such as craniofacial surgery, sinus surgery and neurosurgery. The present report describes an unusual case of OCS due to traumatic tension orbital emphysema (OE).

Case

A 50-year-old male presented to the out-patient department two hours following road traffic accident. The patient had history of loss of consciousness along with nasal bleed, one bout of vomiting and history of blowing through the nose after trauma. The vitals were stable, there was no headache or associated neurological deficit. On examination, patient had midface injury with orbital ecchymosis and edema in the left eye. Occlusion was deranged with palpable step deformity in the mandible. Clinically it was suggestive of Le-Fort II type fracture involving the orbital floor and mandible.

Ocular examination revealed visual acuity 20/20 in the right eye and counting finger close to face in the left eye. Anterior and posterior segment examination of right eye was within normal limit. Examination of the left eye revealed eyelid edema, periorbital ecchymosis, relative afferent pupillary defect and a posterior chamber intraocular lens in situ. On digital ocular palpation there was resistance to retropulsion, and globe was firm suggestive of elevated intraorbital pressure in the left eye. The extraocular movements of left eye were grossly restricted; crepitus was felt at the infraorbital rim along with infraorbital anesthesia. Dilated fundus examination was however normal. On B scan ultrasonography, there was no evidence of either vitreous hemorrhage or retrobulbar hemorrhage in the left eye.

Computerised tomography (CT) scan brain and orbit revealed Le-Fort II fracture on the right side, Le-Fort III fracture on the left side, left para symphysis fracture and multiple air pockets in the intraconal as well as extraconal space of left orbit as shown in the Fig. 1a and b. with a large air pocket in the adjoining cranial cavity probably due to communication through superior orbital fissure. No other cranial bone fractures were seen on the CT scans. We made a working pathophysiology of massive air entry into the orbit during sneezing, vomiting post trauma leading to an increase in the intra-orbital pressure. In spite of there being zygomatic complex fracture which in turn works like a decompression, the air pressure might be massive enough to make an escape through the superior orbital fissure leading to cranial emphysema (Fig. 2).

Fig. 1.

Three-dimensional computed tomography (CT) scan showing left zygomaticomaxillary complex fracture and left inferior orbital wall fracture

Fig. 2.

Coronal CT scan showing extensive presence of air in the left orbit region and the anterior cranium

A preliminary diagnosis of orbital compartment syndrome due to orbital and intracranial emphysema was made. Considering the emergency of situation, patient was immediately taken up for orbital decompression, emphysema release and fixation of fractures thereafter.

Surgery

An emergency lateral canthotomy and cantholysis was done to release the intra-orbital pressure. Then a 1–1.5 cm incision over the medial aspect of upper eyelid just above medial canthal ligament was placed to gain access to the orbital roof and the medial wall. Immediately to opening of the orbital extraconal space, the septal bubbles were noticed and a gush of air was felt. At this point we filled the so created cavity with saline and got the patient to a head low position in anticipation of cranial emphysema air escaping through this. We did notice air bubbles escaping suggestive of cranial emphysema being decompressed. However, as per the advice of the neurosurgeons we didn’t made any attempt to release the cranial emphysema beyond that point. Likewise, even the lateral wall air pockets were explored and air was released. The intraorbital pressure reduction post decompression was noted immediately.

Once the decompression was achieved definitive treatment of the facial fracture which included orbital floor and medial wall reconstruction using preformed titanium mesh and open reduction and internal fixation for the midface through a midface degloving exposure and mandible through intraoral vestibular approach.

Post-operative healing phase was uneventful with one-week postoperative visual acuity of the affected eye improving to 20/200 along with reversal of relative afferent pupillary defect.

Literature Review

Am brief literature search for the term orbital emphysema in PubMed yielded 352 articles out of which 280 articles were identified after screening for appropriate titles and case reports. A total of 138 patients were reported in the literature with severe orbital emphysema.

Clinical Presentation

The clinical presentation depends on the severity of the facial fracture and presence of the pain and pressure in the affected eye with a decrease in visual acuity, and almost always accompanied with the palpable soft tissue crepitus suggestive of subcutaneous emphysema. Most of the cases the entrapped air is found to be localized superiorly and medially in the orbital extraconal space. Due to this characteristic of the superiorly localized air in the orbit, a crescent shaped area of radiolucency is demonstrated on a radiograph which is termed as “black eyebrow sign” and it is highly suggestive of OE [3].

The presentation of OE in an orbital fracture has an odds ratio of 6.19 [4] also OE has a specificity of 99.6% and positive predictive value of 98.4%. for an orbital fracture [5]. In one review of 348 orbits with isolated medial wall fracture they found positive association of OE in 20.1% [6]. they also concluded that OE frequently presented with supraduction on presentation, however majority of these patients had spontaneous recovery with our surgical intervention. There is often a history of post trauma nose blowing, sneezing or coughing which might have precipitated the OE. A bout of vomiting or sneezing increases the pressure in upper respiratory passages forcing the air from the sinuses into the orbit.

Other causes of OE mentioned in the literature are Valsalva maneuver that increases pressure within the sinuses, leading to spontaneous fracture or dehiscence of the lamina paprycea usually during strenuous sports like weight lifting, sinus barotrauma in deep divers due to spontaneous dehiscence of the lamina paprycea, allowing air to gain access to the orbital compartment, spread from deep tissue plane emphysema due to migration of the air, iatrogenic ingestion of air during surgical procedures like functional endoscopic sinus surgery, orbital decompression for thyroid eye disease, balloon dacryoplasty, postconjunctivodacryocystorhinostomy with Jones tubes and during elective rhinoplasty [7].

Lima et al. [8] in a major review on aetiologies of orbital compartment syndrome have mentioned orbital haemorrhage due to various causes including trauma, surgery and other underlying medical conditions to have accounted for 64% of cases of orbital compartment syndrome. Orbital emphysema due to traumatic orbital fractures, compressed air injuries and sinus surgeries have also been reported as one of the less common causative factor [9]. There are other important aetiologies of OCS such as fulminant orbital cellulitis or intraorbital abscess, inflammation and tumours [7, 10–13]. Less commonly, prolonged hypoxemia with a capillary leak, foreign material in the orbit, massive fluid resuscitation after burn injury, or position-dependent oedema can result in an acute rise in orbital pressure.

Pathophysiology

Orbit, being a confined space with definitive boundaries and approximate volume of 30 ml, with an intraorbital pressure of 3–6 mmHg, is known to have a limited compliance related to limited elasticity of the septum and tarsal plates, beyond which it results in an increased intra-orbital pressure [2]. Hargarden et al. [14] in their study on primates of simulating the increased intra-orbital pressure by placing a catheter in the retrobulbar space and inflating with saline for minimum of 180 min found that the visual loss was attributed to the prolonged ischemic damage to the optic nerve.

Orbital fractures associated with other maxillofacial fractures usually lead to communication of the orbital cavity with the adjacent aerated cavities like medial wall fractures communicate to nasal cavity, orbital floor with maxillary sinus and roof with the frontal sinus. Orbital emphysema thus developed due to pathological communication between the orbit and these aerated cavities, which in turn may be aggravated by factors like sneezing, coughing, nose blowing and air travel [13]. The association of OE to the medial wall fracture of the orbit follows Poiseuille law of fluid dynamics wherein smaller volume ethmoid sinus reaches equivalence with the intranasal pressure quicker than the larger maxillary sinus, forcing air towards the orbit more rapidly [15]. The air in the orbital cavity presents a ball-valve effect, whereby orbital tissue allows air entry and sequentially blocks its exit which results in progressive increase in pressure in the orbit. Due to this one-way valve mechanism caused by a lobule of orbital fat present at the fracture site, air enters and remains trapped in the orbit leading to OCS.

A case of pneumocranium following soft tissue injury to medial orbit from goat’s horn has been reported [15]. Probability of OE spreading intracranially through superior orbital fissure or along the optic nerve sheath cannot be ruled out. Hence, orbital emphysema needs close a follow-up and caution is advised in all these cases.

Management Review

Literature mentions needle decompression with/without lateral canthotomy and cantholysis, orbital decompression surgery and were even managed with hyper baric oxygen therapy with comparable results. In addition to decompressing the orbit, the communication between the sinus and the orbit or nasal cavity and the orbit should be addressed with surgical closure using appropriate reconstructive materials (Fig. 3).

Fig. 3.

Flowchart summarising orbital emphysema and its management

The vast majority of the cases of OE are self-limiting which usually resolve within 7–10 days [7]. However cases of loss of vision secondary to compressive optic neuropathy is reported. Hence acute orbital compartment syndrome needs to be recognized and addressed in an emergency basis to achieve decompression so as to prevent an irreversible vision loss.

Conclusion

Orbital emphysema causing orbital compartment syndrome is a rare clinical phenomenon. In most of the cases, the co-existing maxillofacial trauma which in turn acts like decompression so as to limit the damage. However, rarely the air entry pressure might be so much that it can increase beyond the compensated orbital volume so as to lead to orbital compartment syndrome and also even rarely cranial emphysema. A note of caution to all the orbital surgeons to carefully look for any entrapped air and release any emphysema prior to reduction of the fracture, because we are the opinion that if the fractures are reduced without air release it might lead to build-up of intraorbital pressure there by leading to postoperative OCS. Probably this explains why there are few cases of blindness postoperatively. So watchful eyes, an accurate diagnosis and timely surgical intervention could potentially reverse permanent damage to the optic nerve.

Funding

No funding has been received by any author in relation to this study.

Compliance with Ethical Standards

Conflict of interest

All authors declare that they have no conflict of interest.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed Consent

A written informed consent was obtained from all individual participants included in the study.