Complications of Facial Trauma of the Frontoorbital

Transcription

1 581 Complications of Facial Trauma of the Frontoorbital Region Patrick W. Cleveland, MD 1 Jesse Ellis Smith, MD, FACS 2 1 Department of Otolaryngology, Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 2 Department of Otolaryngology, Fort Worth, Texas Address for correspondence Jesse Ellis Smith, MD, FACS, Department of Otolaryngology, 923 Pennsylvania Avenue, Fort Worth, TX ( smith_je@yahoo.com). Facial Plast Surg 2017;33: Abstract Keywords orbital frontal sinus complications frontal sinus fractures orbital fractures Traumatic injuries to the orbitofrontal region place some of the most important structures of the face at risk: the eyes, frontal skull, and brain. A thorough knowledge of complications from resultant trauma, and from attempted surgical corrections, is necessary to offer patients the best outcomes, ensuring proper healing with excellent long-term results. Traumatic injuries to the orbitofrontal region place some of the most important structures of the face at risk: the eyes and brain. One of the leading evolutionary theories as to why the paranasal sinuses exist is to provide a crumple zone, to absorb energy from trauma, and to protect these vital structures. When managing fractures of the orbit and frontal sinus, it is important to keep this purpose in mind and understand the complications that can ensue. Identifying these complications early offers the greatest chance of preserving normal function to these structures and will dictate how and when to manage each fracture. This idea extends beyond complications of primary trauma, but also encompasses the trauma caused by surgery and open reduction. A complete knowledge of the possible complications of each intervention can help surgeons avoid common pitfalls that could worsen their patient splight. Complications of Orbital Trauma The sequelae of orbital trauma are far ranging both in debilitation and duration. Symptoms can be limited to temporary swelling without any visual impairment, to irreversible blindness, and necrosis of extraocular muscles. Prompt recognition of orbital fracture complications is by far the most important step in managing orbital fractures. Once recognized, appropriate interventions can be made in a timely fashion. In the modern era, an accurate physical exam often occurs secondary to computed tomography (CT) imaging, as it is readily available throughout most of the modernized world. However, given the sensitive nature of the structures of the orbit, specifically the retina, the ability to clinically recognize severe impending complications can make the difference in preserving important structures and vision. Orbital Compartment Syndrome and Retro-orbital Hematoma The orbit is a confined space and it is important not to lose sight of this fact when evaluating patients who have recently sustained orbital trauma. It takes the shapeofa bony pyramid onits side with only the base of the pyramid composed of soft tissue. Although the base of the orbital pyramid is open, it has minimal compliance because it is composed of several structures designed to keep the orbital contents held within the orbital pyramid. The tarsi form the structural core of the superior and inferior eyelid, made of dense fibrous tissue approximately 1 mm thick, theyextend along the eyelid margin andgive riseto the medial and lateral canthi. The lateral canthus then inserts onto the lateral orbital tubercle, or Whitnall s tubercle.the medial canthus is intimately related to the canaliculi of the lacrimal system and its components travel to the lacrimal sac where they insert onto the lacrimal sac fascia, anchoring the medial canthus to the lacrimal bone medially. Superiorly and inferiorly the orbital contents are restricted from herniating from the orbit by the orbital septum. The orbital septum forms a diaphragm extending from the periosteum of the orbital rim margin, termed the arcus marginalis, to the lid retractor structures near the lid margin. More superficially, this is Issue Theme Aesthetic Management of Upper and Midface Trauma; Guest Editor, Yadranko Ducic, MD, FRCS(C), FACS Copyright 2017 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) DOI /s ISSN

2 582 Fronto-orbital Fractures Cleveland, Smith reinforced by the orbicularis retaining ligament. 1 Due to the seminoncompliant structures, there is little tolerance for spaceoccupying lesions such as intraorbital bleeding or mass effect. Orbital bleeding results in increased intraocular pressure which then may surpass the venous filling pressure. This causes a collapse of the vein and compromises venous outflow. Thus, a vicious cycle is created in which pressure rapidly climbs, as there is no egress for blood. As the pressure builds, as a result of the high pressure arterial inflow, the capillary beds gradually collapse. Oxygen supply to the delicate neurosensory structures of the orbit is diminished, causing ischemia. If this pressure is not released from the orbit by emergent orbital decompression in a timely fashion, ischemic changes become irreversible. Decompression can be achieved swiftly via lateral canthotomy with cantholysis and/or a transeptal orbital incision. The clinical signs and symptoms can evolve over minutes and include tense and painful progressive proptosis, induration of the orbital structures upon palpation, periorbital edema, elevated intraocular pressure, and restricted intraocular movements with diplopia. As ischemic changes progress, patients also develop a mydriasis with deficient pupillary light reflex, cherry red macula, edematous optic disk, an afferent pupillary defect, along with progressive, declining visual acuity, which is a hallmark sign of this condition. It should be noted that orbital compartment syndrome (OCS) can happen irrespective of fracture, and that a patient s anticoagulant history should be known, as blood thinners and antiplatelet agents make OCS more common after periorbital trauma. In patients with decreasing visual acuity, treatment should not be delayed for imaging or ophthalmologic diagnosis. Once decompression is performed, then it is safe to proceed with this further diagnostic evaluation to ascertain more information and isolate the exact cause. In the vast majority of cases, this means surgical exploration, hematoma evacuation, and hemostasis; however, detailed anatomic information can help expedite locating the source and minimize the trauma from surgical exploration. Expert opinions vary on the amount of time after injury, one has until irreversible loss occurs and range between 15 and 90 minutes. The incidence of OCS is reported between and 2.4% depending on the cohorts inclusion criteria, but they all paint the same picture; it is an uncommon occurrence in orbital trauma but one that requires immediate action and risks permanent vision loss if emergent decompression is not done. 2 7 A rare cause of OCS can be from a common finding: orbital emphysema. There have been reported cases of minimally displaced fractures acting as a one-way valve; therefore, any nose blowing, sneezing, or positive pressure forces air into the orbit without the ability to relieve the pressure. These cases developed the same signs and symptoms as any other patient with OCS and required emergent canthotomy. Once imaging was performed and patients were found to have only orbital emphysema, the air was then decompressed. This can be managed with needle decompression under local anesthetic if it appears accessible on CT; otherwise, surgical intervention is required Entrapment of Extraocular Muscles Muscle entrapment is an uncommon finding and is especially rare in adults but one that must be ruled out upon initial assessment. Entrapment occurs when a rectus muscle or its sheath is trapped between bone fragments. The medial or inferior rectus muscles almost exclusively represent the muscles involved in cases of entrapment since the adjacent bony structures of the orbit are the thinnest and most commonly fractured. The need for early intervention is generally advocated as the vascular supply to these muscles can become compromised resulting in necrosis, fibrosis, and scarring. There are several studies that even suggest incomplete or prolonged recovery from diplopia with delayed intervention due to irreversible damage to the rectus muscle The initial diagnosis of entrapment can often be difficult to differentiate from limited extraocular movements from swelling and pain, and can be clarified by imaging and forced duction testing. The constellation of bradycardia, nausea, and syncope can be seen with attempted extraocular movement in cases of entrapment. This triad has been termed the oculocardiac reflex (Aschner Dagnini s reflex or Aschner s phenomenon), and has been reported in rare cases to cause bradycardic arrest and asystole. Given the typical clinical setting of trauma, it is important to rule out other causes of bradycardia and syncope such as intracranial bleeding (Cushing s reflex), primary arrhythmias, and electrolyte disturbances. If entrapment is suspected, eye movement should be limited to minimize reflexive bradycardia. 15,16 A sustained oculocardiac reflex is an indication for immediate surgical intervention. The pediatric population has a higher incidence of entrapment because of the higher frequency of greenstick fractures; however, even within this population, the rate is low. Broyles et al found a rate of entrapment in a review of 76 pediatric orbital floor fractures spanning 21 years to be 5.3%. 17 Examination of extraocular movement can be difficult in children; thus, practitioners often must rely heavily on imaging, since forced duction testing usually requires general anesthesia. Cohen and Garrett suggested that intractable nausea and vomiting in the setting of a trapdoor fracture (floor fracture with <0.5 cm of displacement and attached at one end) are a useful surrogate for entrapment, with a positive predictive value of 83.3% in six cases of entrapment seen. 18 Often these entrapped children may have minimal external signs of trauma such as ecchymosis, injection, or periorbital edema, and appear only to have vertical gaze limitations on exam. This is because hydraulic forces caused by blunt trauma to the globe that lead to these minimally displaced orbit fractures necessary for entrapment are lower in energy than large blow outs, and thus, are more occult in appearance. This exam has been coined the white-eyed fracture and a high suspicion for entrapment should prompt further evaluation with immediate CT imaging. If entrapment is seen on CT, then immediate operative intervention should ensue. A CT finding of a missing rectus, or the absence of the inferior rectus above the orbital floor on coronal CT, should be equated with entrapment and managed accordingly

3 Fronto-orbital Fractures Cleveland, Smith 583 Hypoglobus Hypoglobus (enophthalmos or hypophthalmos) is one of the most common complications seen after orbital fractures, especially blowout fractures, where an entire segment of floor or medial wall becomes displaced into the adjacent sinus. The effect of this is an expansion of the orbital volume, and as a result, the fixed amount of orbital contents then herniates into the dependent defect, causing a sunken appearance to the globe. A small degree of hypoglobus can often be tolerated from an aesthetic and functional perspective. As the degree of hypoglobus increases, diplopia and obvious asymmetries ensue. This is a progressive continuum and has in the past been the center for debate in respect to what defect size or degree of hypoglobus can shift the risk benefit ratio in favor of open reconstruction of the orbit. Generally accepted guidelines for immediate operative repair of orbital fractures include early hypoglobus causing facial asymmetry and diplopia, as well as the aforementioned white-eyed fracture and entrapment with sustained oculocardiac reflex. Oftentimes, edema and hemorrhage obscure the presence of hypoglobus in the first 24 to 72 hours; therefore, patients who develop significant hypoglobus after swelling subsidesinthefirst several days should receive open repair within 10 to 14 days of the offending trauma. Typically, less than 2 mm of hypoglobus or >50% loss of the area of the orbital floor are used as cut offs for patients at significant risk of facial asymmetry and possible diplopia. If these large orbital floor defects go untreated, fat atrophy and scarring to the maxillary antrum ensue, leading to a late finding of hypoglobus or enophthalmos. At this point, surgical repair becomes more technically challenging and may result in suboptimal outcomes A recent metaanalysis by Damgaard et al found repair outside this window to correlate with statistically significant higher incidence of persistent diplopia and enophthalmos. Infraorbital Nerve Entrapment Infraorbital nerve entrapment is another complication of orbital floor fractures that should be evaluated in the initial physical exam. Often this is not immediately apparent, as pain is not an unexpected consequence of trauma; however, if pain persists after swelling has subsided or extends beyond the traumatized area in the distribution of the infraorbital nerve, neural entrapment should be suspected. There are case series oforbital floor fractures with infraorbital nerve entrapment on coronal CT imaging where surgical intervention improved infraorbital nerve hypesthesia that was progressive in nature. It is important to stress to the patient that their pain may persist despite surgery, and this must be discussed with the patient prior to surgical intervention. 19,22,23 Cerebrospinal Fluid Leak Much more uncommon than medial wall and floor fractures, superior orbital wall fractures can occur from trauma to the orbital rim and forehead. Unlike fractures limited to the floor and medial wall, superior orbit fractures can provide a site of egress for cerebrospinal fluid (CSF). CSF leaks can present as oculorrhea (appears like epiphora), chemosis, and persistent upper lid swelling. Thesehave been reported as being managed in a variety of different ways, from antibiotics, bedrest, observation, to lumbar drain placement, and neurosurgical intervention with repair of the affected dura. The degree of trauma and severity of the defect should dictate management. In minimally displaced fractures, a conservative management approach tends to be successful. If conservative management is undertaken, any orbital intervention should be deferred, since the orbital contents often tamponade the leak site. Delaying operative intervention for other fractures is thought to minimize the risk of recurrent leaks and menegitis Orbital Cellulitis Prophylaxis for orbital cellulitis after orbital fracture and the role of antibiotics are an important topic since practices vary widely. A recent systematic review in 2015 by Mundinger et al attempted to tackle this issue and found that despite the literature overwhelmingly advising against pre- and postoperative antibiotics, those surveyed continued to prescribe antibiotics 47 and 71% of the time, respectively. They did note, however, that despite its congruence, the current body of literature is limited to retrospective studies and expert opinion and does not include any high-quality prospective studies or account for variety of fracture types. There are definite instances where the authors agreed antibiotics before and after surgery were warranted, such as when there is an active sinus infection, upper respiratory infection, wound infection, or concern for a CSF leak. Recent studies further support the notion that orbital cellulitis is no more common in patients who do not receive antibiotics than those who do. It has also been noted that many trauma patients are treated with a multidisciplinary team approach, and antibiotic prophylaxis with multiple agents has been seen to occur. This highlights the need for good communication among practitioners to avoid unnecessary antibiotic usage. If it is felt pre- or postoperative antibiotics should be prescribed, then it is best to avoid broad-spectrum agents, and the duration should be limited to 5 to 7 days. 27,28 Monocular Diplopia Though many of the previously discussed complications can lead to diplopia at rest or with vertical and horizontal gaze, it should be noted that these are all causes of binocular diplopia. Monocular diplopia can also be associated with orbital trauma. The high-energy forces coursing through the globe can result in lens subluxation, corneal scarring, and damage to the anterior globe changing the optics of light transmission, and in some cases, projecting more than a single image on the retina. Cataract formation can lead to this as well, but this does not present acutely. The presence of this finding after trauma warrants ophthalmologic evaluation, but usually does not require urgent surgical intervention. 29 Ophthalmologic Complications It is important to note the forces involved in orbital trauma put tremendousstress on the globe and complete evaluation of injury to the globe via ophthalmologic consultationshouldbeconsidered for all cases of orbital trauma. Some of the most common injuries that can affect the eye itself are shown in Table 1. 30,31

4 584 Fronto-orbital Fractures Cleveland, Smith Table 1 Eyelid Cornea Conjunctiva Common injuries of the eye Anterior chamber and iris Lens Retina Optic nerve Nasolacrimal duct injury Tarsal plate injury Corneal abrasion Foreign body Subconjunctival hemorrhage Chemosis Complications of Orbital Repair Hyphema Acute angle closure glaucoma Iridodialysis Traumatic iritis Lens subluxation Capsule rupture Retinal detachment Vitreous bleed Traumatic retinal edema Compression from fracture or bleeding Transection Like all surgeries, the potential risks and benefits of surgical intervention must be weighed and discussed with the patient, as surgery in the orbit is not benign. Some texts have estimated the incidence of blindness following orbital surgery to be 0.3% in the acute setting, and 0.06% when delayed repair is attempted. 32 Some of the most common complications and potential pitfalls are addressed later. Incisions The first operative consideration to make is how to approach the orbit and expose the area of interest. If there are lacerations available, it is acceptable to use these incisions to approach the orbit; however, this is rarely the case. The options for incisions include the transconjunctival incision with or without a lateral canthotomy, subciliary incision, mid-eyelid incision, transcaruncular incision, or a rim incision. All of these incisions will provide adequate access to the infraorbital rim and orbital floor. The main advantage of the transconjunctival approach is the lack of a visible skin incision. Furthermore, if access to the medial orbital wall or zygomaticomaxillary complex is needed, the incision can be extended with a transcaruncular incision medially or a canthotomy laterally. A canthotomy should not be needed to access isolated floor fractures, but in the case of multiple facial fractures or extreme edema, this can be a useful approach to extend the operative field laterally. It is important to resuspend thelateral canthus if a canthotomy is performed, as failure to do so will cause the lateral canthus to droop and round, leading to obvious asymmetry. Resuspension can be technically challenging, as minute errors result in obvious asymmetry; thus, lateral canthotomy should be reserved for cases where extra exposure is required. Likewise, the transcarunucular incision extends the dissection near the nasolacrimal duct, and care must be taken during dissection to avoid this structure. Transconjunctival incisions carry a higher relative risk of entropion than lower lid incisions (which carry a higher risk of ectropion). However, the overall risks of either are much lower in transconjunctival incisions. In incision types, complications are often transient and improve with massage, lubrication, and taping. It should be noted that external lid incision does carry a higher risk of permanent scleral show. For prevention of both entropion and ectropion, a Frost suture is often placed through the lower lid tarsus and taped to the forehead, to counter the forces of gravity and contracture; thus, restoring the natural position of the lower lid during early wound healing. When using a transconjunctival approach, some authors believe that closing the periosteal defect and conjunctival defect promote scaring and may contribute to cicatricial entropion. Others recommend gentle lid retractions during exposure to avoid stretching the lid tissue or causing injury to the tarsal plate. Baumann and Ewers believe that incision placement 2 to 3 mm inferior to the tarsal plate minimizes the risk of vertical lid shortening from fibrosis of the tarsus while placing the incision high enough to prevent adherence of conjunctiva, fat, and/ or muscle to the infraorbital rim, thus minimizing the risk of entropion. The overall rate of entropion remains low; in the largest cohort reported in the literature, there was a 1.2% rate of entropion and ectropion in 664 transconjunctival incisions. In this study, the only other reported incisional complications were three cases of nasolacrimal duct injury, two tarsal plate injuries, and a single corneal abrasion, demonstrating this to be a safe and aesthetic approach to the orbital floor. Regardless of your choice of incisional approach, it should be noted in cases of polytrauma requiring a bicoronal incision to the approach, the frontal sinus and anterior cranial fossa (ACF), eyelid incisions should be made prior to the bicoronal flap, since edema from raising the forehead flap can obscure the lower lid approach when orbital dissection is attempted afterword Plating the Defect Understanding both the geometry of the defect and the desired volume of the orbit are essential in orbital repair. The goal of all orbital reconstruction is to restore the intraorbital volume, position, and function of the orbital contents. Orbital volume can be normalized in one of two ways after the contents have been gently brought back into the proper position in the orbit: either the fractured segment is reduced back into place and secured, or more commonly, an onlay graft or implant can be placed over the defect preventing herniation of the orbital contents. Many of the complications seen postoperatively come from preventable technical errors with plate placement. Despite there being a common goal when fixing orbital fractures, the challenges come from the heterogeneity of orbit defects. The plate should ideally span the defect to support the orbital contents, extend just beyond the fracture margins with a landing area on all four sides, and recreate the contour of

5 Fronto-orbital Fractures Cleveland, Smith 585 the orbit to restore the orbital volume to normal. When trimming the plate to size, it should extend onto the supporting ledges on all four sides but no more than is needed to prevent the plate from falling into the adjacent sinuses. The reason for this is excess plate increases the chances that periorbital contents now restored to the orbit become entrapped by the plate. One way to monitor this is with serial forced duction testing throughout the surgery. A baseline should be established at the beginning of the case, again after normal mobility is attained if entrapped tissue is freed, and after the plate is placed. The plate should be placed in a tension-free fashion, and if pressure is needed to hold it in place, or placement limits movement on subsequent forced duction testing, the plate should be removed. Either further elevation is necessary or the plate needs to be trimmed. This is especially important posteriorly, since visualization is difficult, space is limited, and the most important structures lie in the posterior most aspect of the orbit. Care must be taken to strike the right balance when trimming plates posteriorly since visualization of the implant resting on the greater wing of the sphenoid, ethmoid, and lacrimal bones can be difficult. The plate can be sitting over the ledges anteriorly, medially, and laterally, but if the posterior portion does not have purchase, it can hang into the maxillary or ethmoid sinus despite the appearance of being well placed. It is important to visualize the 30 degree upward slope of the orbital floor and ensure that the reconstruction appropriately recreates the same angulation. Verification is traditionally done visually and should be confirmed with intraoperative or postoperative imaging. Intraoperative CT scanning is now available and has shown to be a great asset in the verification of proper plate size, placement, and contour during orbital repairs. Borad et al found in a retrospective review of their repairs that use of intraoperative imaging over 7 years resulted in a change in operative management in 44% of cases. 39 Surgical navigation is also beginning to have an impact on intraoperative decision making. Navigation software allows for mirror image of the uninjured orbit to be superimposed over the injured side, and then the navigation probe can be used to assess the position of the plate relative to this ideal contour. Not only does this provide improved confirmation that the plate spans the fractured defect but it also allows the contour of the plate to be compared with the contralateral orbital contour. Zavattero et al found that not only did navigated surgery help more reliably recreate the orbital contour and better restore the orbital volume, but it also led to decreased postoperative diplopia and drastically reduced the need for reoperation. 40 Accurately recreating the bony contour is not limited to high-tech intraoperative aids, though faithfully reproducing the correct shape becomes more challenging as the size of the defect increases. This is especially true of defects that span the inferior and medial orbital wall as the transition between them is geometrically complex and difficult to recreate without any aid. For these complex-shaped defects, many surgeons use prebent plates that are available commercially to recreate the natural contour. Though these merely recreate an average orbital contour, and are not patient specific, usually they restore volume to within a clinically acceptable tolerance. A sterile skull can be used intraoperatively to again mold the plate to a generic orbit prior to making finer adjustments in vivo. Preoperative models can be made from three-dimensional reconstruction of CT imaging which allows for implants to be prebent and sterilized. Computer-aided design and manufacturing technologies have been used to recreate a patient-specific ideal contour of the orbit allowing for the production of custom plates and implants. There is no one technology that is best for all defects, but being familiar with these contouring aids will undoubtedly improve each surgeons ability to more skillfully restore the orbit to the appropriate volume Orbital Adherence Syndrome Titanium mesh has become one of the most common materials used for the reconstruction of orbital defects, and has many properties that make it desirable for reconstructing bony defects. It can be bent to easily recreate the shape of the orbital floor, it integrates well into bone, has a low risk of extrusion, minimally distorts CT imaging, and it is readily available. Part of the reason it integrates into bone well is that it forms a thin layer of titanium oxide when exposed to air which in turn promotes the release of transforming growth factor-β and platelet-derived growth factor. These promote fibroblast proliferation enhancing adherence but also form dense scarring noted to extend as far as 5 mm from the plate itself. This has led to the idea of orbital adherence syndrome, in which the plate repairing the defect can cause extensive fibrosis, which in turn restricts the movement of the adjacent rectus muscles and overlying tissue. This can lead to the onset of late diplopia and cicatricial eyelid retraction as wound healing and wound contraction progress. Lee and Nunery have reported improvement in symptoms with removal of titanium implants and reconstruction of the floor defect with nylon foil (Supramid; S. Jackson, Inc.). After 102 patients were repaired with nylon foil, this group showed good results without evidence oforbital adherence syndrome, with only one patient developing progressive enophthalmos. Some plate manufactures now offer titanium plates covered with porous polyethylene (Medpor; Stryker Corp.) to combat this occurrence. Though currently there are limited studies detailing this phenomenon, orbital adherence syndrome is an emerging entity that should be entertained when patients develop diplopia in the weeks after surgical correction with titanium implants Nerve Injury Injury to the infraorbital nerve is not an uncommon risk of orbital repair. The nerve can at times be found adherent to the fracture contents if the infraorbital canal is involved in the fracture. If this is the case, it can provide a valuable landmark in estimating the natural 30 degree upward slope of the orbital floor. As dissection progresses posteriorly, the nerve provides an ideal plane of dissection for large floor fractures, since the herniating fat envelopes the nerve. This can be gently teased off the infraorbital nerve, as all the soft tissue contents superior to the nerve are periorbital structures that must be preserved and retracted back into the

6 586 Fronto-orbital Fractures Cleveland, Smith orbit. During retraction and plate placement, however, care must be taken to preserve the infraorbital nerve. Not only can numbness ensue but if the plate entraps the nerve, hyperesthesia can follow and require repeat surgery to correct the iatrogenic entrapment. 41 Pediatric Considerations It is important to consider pediatric orbital fractures in a different way than those in adults. Children have soft pliable bones that tend to bend and recoil when traumatic loads are placed on them. The result of this is a decrease in blowout fractures and in increase in linear and trap door fractures. As these bones bend, they often snap back into place immediately, outpacing the recoil of the now herniated periorbital soft tissue, leading to a minimally displaced fracture that entraps periorbital components. As a result of this process, the primary surgical goal is often the release of incarcerated tissue, and then to restore orbital volume. As these pliable bones maintain their shape, once entrapped muscles and periorbital contents are returned to the confines of the orbit, the fractured bone may preserve the orbital volume without any further plating or manipulation. It is important to release the entrapped tissue in an atraumatic fashion. One pitfall is to attempt pulling the entrapped tissue out without releasing tension. This is a recipe for destroying the delicate periorbital structures. Instead, the fracture should be further depressed outward to gain enough space to release the entrapped tissue. If this fails to accomplish the extrication, removing a small amount of bone at the margin of the fracture may be helpful. This will release the purchase of the bone from the soft tissue and can often be accomplished without the need for reconstructing the small ensuing defect. Conservative management of pediatric defects is important because pediatric orbits are growing orbits. Permanent plating can disrupt growth and tether growing bones, leading to more asymmetry than the actual fracture. Some surgeons use absorbable plates for this reason. These can be fixed or placed in an onlay fashion. Some surgeons still use titanium to plate fracture segments back into place, but most advocate a second surgery for removal after healing has completed. 41,54 56 Complications of Frontal Trauma The frontal sinus shares a common purpose to the other periorbital sinuses, in that it provides a crumple zone to absorb energy, thus protecting the ACF. The frontal sinus has two layers of protection, the anterior table and posterior table. Traumatic injury to the frontal sinus can cause minor cosmetic contour deformities of the forehead or comminuted posterior table injuries associated with severe and sometimes life ending cerebral trauma. In high-energy injuries that extend to the posterior table, it is important to address frontal sinus reconstruction with a team approach that involves neurosurgical colleagues. In the end, all frontal sinus reconstruction aims to prevent infectious intracranial complications, restore facial contours, and if preserved, maintain frontal sinus aeration and drainage. Posterior Table Involvement Involvement of the posterior table of the frontal sinus is very common and has been reported to occur during 80% of all frontal sinus fractures requiring surgical management. 57 Though the anterior table is the thicker of the two, neither the anterior table nor the posterior table is particularly robust. The individual anatomy of the frontal sinus plays a key role in the fracture pattern and involvement of the posterior table, as well as damage to the contents of the ACF. Increased frontal sinus volume is thought to allow for dispersion of a traumatic force over a greater distance, and has been shown to correlate with a lower incidence of cerebral contusion, intracranial hemorrhage, and less need for operative intervention. When the forces involved are strong enough to transmit to the posterior table with enough force to cause a fracture, concern is high for intracranial injury. Repair should be performed for underlying intracranial complications prior to attempting cranial facial reconstruction. However, if a patient is stable and neurologically intact, with normal intracranial pressures, some surgeons have shown that reconstruction may be attempted at the time of an initial neurosurgical intervention. The most common intracranial interventions include abscess drainage, CSF leak repair, decompressive craniotomy, drainage of intracranial hematoma, repair of dural tears, or even cranialization of the sinus itself. When the posterior table is comminuted or severely displaced (>5 mm), it is often unsalvageable. If the ACF cannot be sealed off from the frontal sinus, it is necessary to either obliterate this sinus or cranialize it. This is because of the risk of meningitis and abscess formation, which can occur as 25 to 31% prior to dural repair, with a 10-year cumulative risk estimated to be as high as 80%. Though the exact rate is difficult to study and quantify, surgical repair of dural defects has been shown to decrease the risk of meningitis from 30.6 to 4% after surgery, and the 10-year cumulative risk from 80.5% down to 7% It should be noted that not all patients with posterior table fractures and dural tears will develop clinically evident CSF leaks, as brain parenchyma can tamponade the leak site, preserving a site of bacterial ingress. In Baker et al s two decades review of 163 patients with frontal trauma, they noted that of all patients with dural tears, CSF leakage was seen clinically in only 30%. In many institutions, the standard indication for operative exploration is CSF leakage, but Baker et al s notes in their practice CT imaging have become a more useful guide. Their internal review showed that fracture displacement greater than the width of the bony lamellae of the posterior table was 93% sensitive for dural tears. The implication of this may be that many more posterior table fractures deserve consideration for operative exploration to prevent infectious sequelae. 61 Part of this issue with aggressive surgical repair of these fractures is it is not without morbidity both intracranially and cosmetically. Furthermore, imaging and endoscopic techniques have advanced substantially since the data demonstrating high infection rates was initially collected. Dalla Torre et al have proposed a shift to CT evaluation of fracture displacement to guide the need for surgical management in the otherwise asymptomatic patient as well. They reserved

7 Fronto-orbital Fractures Cleveland, Smith 587 surgical intervention on posterior table fractures for patients with CSF leakage, fractures >5 mm in displacement, nasofrontal duct injury, or patient having other concomitant fractures requiring intervention. The remaining asymptomatic posterior table fractures (<5 mm) were managed with observation. At 2 years, they showed very acceptable in 164 patients with a complication rate of 2.4%, all of which were from aesthetic deformity due to anterior table fractures in patients who were offered and refused surgery. 62 Other studies have shown that attempting to manage posterior wall fractures that are moderately displaced (<5 mm) with sinus preservation is safe, with no increased intracranial infection rates noted. Though much of the recentdata make a strong case for conservative management, it is primarily limited by its follow-up length, as not enough time has passed to accurately evaluate long-term infectious sequelae. There still fails to be a consensus on how frontal sinus fractures should be managed, but from the recent literature trends, one thing is clear; there has been a paradigm shift toward observation for asymptomatic isolated posterior table fractures that are minimally or moderately displaced. 61,63 67 Mucoceles Mucoceles can be both a complication of trauma as well as surgical repair. Though they can form in any sinus, the frontal sinus is the most common location representing 65 to 98% of mucoceles. They form as when a mucosally lined space loses all outflow pathways. The ensuing nonventilated, closed cavity contains mucin-producing goblet cells, which cause progressive accumulation of mucous. Over time this expands, which can result in compression and erosion of adjacent structures; however, this process can take years. When left to continually expand, they cause an impressive amount of damage to the adjacent structures, eroding into the cranial vault, forehead, and orbit, and in rare cases causing blindness. Mucoceles are at further risk for becoming infected, forming mucopyoceles. The diploic veins of the frontal sinus allow for venous communication, both intracranially to the dural venous sinuses and to the surrounding bone. When untreated, mucopyoceles can progress to sepsis, encephalitis, brain abscess, osteomyelitis, Pott s puffy tumor, cavernous sinus thrombosis, and meningitis. If these infectious complications are encountered, it is important to address the underlying mucopyocele in addition to the presenting complications. If the mucopyocele is left untreated, recurrent complications can occur, including septic emboli propagating intracranial spread via the diploic veins. For example, Pott s puffy tumors (frontal bone osteomyelitis with subperiosteal abscess) may be a presenting complication mistakenly treated with drainage and antibiotics alone like most other facial abscesses without the underlying source being identified or surgically corrected. When these complications occur in the absence of sinusitis, it is importance to look for the presence of a mucocele especially in patients with a history of head trauma. 68 Given the natural history of mucoceles, they may be asymptomatic for years to decades, with reports of patients presenting initially 35 years out from trauma. The treatment for mucoceles and mucopyoceles varies according to the ability to access them endoscopically. Modern endoscopic frontal sinus surgery techniques allow for marsupialization of most mucoceles resulting in far less morbidity than traditional open techniques. If extensive erosion has occurred requiring reconstruction, then an endoscopic approach may not be viable, and open techniques are likely necessary. Cranialized and obliterated sinuses are typically not amenable to endoscopic repair. It is important to note when sinus obliteration and cranialization is attempted, meticulous removal of mucosa from the sinus and all underlying bone must be done to ablate any invaginations of mucosa in the pits of Breschet. There is no consensus on posttraumatic or surgical monitoring; however, annual exams, interval sinus X-rays, as well as surveillance imaging 5 to 7 years after trauma have all been suggested as viable ways to monitor for mucocele formation after trauma. Early detection is preferred as discovering them prior to the development of complications results in less morbidity to the patient with less invasive surgical correction Nasofrontal Duct Injury The patency of the nasofrontal duct (frontal sinus outflow tract) is an important consideration in the management of frontal sinus fractures. If obstructed from posttraumatic scarring or displacement of fracture segments, patients may go on to develop mucoceles or chronic frontal sinusitis; both can lead to devastating infectious sequelae such as meningitis, abscess, or osteomyelitis. Traditionally, when a fracture involved the nasofrontal duct, obliteration of the duct and sinus were thought to be necessary. This is a labor intensive process, not without a significant risk for complications including mucocele formation, demineralization of bone, infection of obliterative graft, and poor cosmetic outcome. Furthermore, not every patient with an injury involving the nasofrontal duct will develop complete stenosis of the outflow tract, with some studies demonstrating spontaneous ventilation of the frontal sinus in up to 88% of nasofrontal duct injuries. In the past two decades, frontal sinus surgery has advanced tremendously, as surgical tools, imaging, and technology have now made endoscopic access to this area possible, with the pioneering effort widely attributed to Wolfgang Draf and the surgical techniques that now bear his name (Draf 1, 2a, 2b, and 3 frontal sinusotomy). These techniques have largely replaced open surgical management of chronic sinusitis, polyposis, and mucoceles, demonstrating a high degree of safety and efficacy. In the frontal sinusitispopulation, these techniques have been shown to have satisfactory outcomes while lowering morbidity, compared with traditional open techniques. The most challenging part of this paradigm shift has been correct patient selection. Patients with substantial posterior table fractures that cannot be reduced into place, CSF leaks, cerebral communication, or severe nasofrontal duct obstruction with >2 mmof displacement should still undergo traditional obliteration with or without cranialization. In contrast, when anterior or posterior table fractures are minimally displaced, there is no CSF leak and no significant intracranial injury, nasofrontal duct injuries do not necessitate obliteration and sinus preservation can be considered. CT imaging with <2 mm cuts formatted in all three axes are needed to evaluated the nasofrontal duct to determine

8 588 Fronto-orbital Fractures Cleveland, Smith if the posttraumatic anatomy is amenable to endoscopic intervention. Having these thin cuts in all three axes is critical for proper evaluation and has been shown to allow for adequate evaluation of the frontal sinus outflow tract in 96% of patients. The lack of thin cuts and multiple planes drops visualization of the frontal sinus outflow tract to 89 and 71%, respectively. Conservative management of nasofrontal duct injuries starts with the repair of any indicated anterior table fractures. These should be reduced and rigidly fixated; however, sinus obliteration is not performed. Patients are then placed on 4 weeks of antibiotic therapy and observed with serial CT scans at 8 weeks, 16 weeks, 6 months, and 1 year for the return of ventilation to the frontal sinus. If the outflow tract fails to spontaneously ventilate, then endoscopic rescue surgery is attempted to recannulate the nasofrontal duct with the appropriate Draf frontal sinusotomy based on individual anatomy. This is the algorithm Smith et al published in 2002 and has shown promising results. The advantages of conservative management are less morbidity, less operative time, the ability to monitor patients endoscopically, and improved visualization of the frontal sinus on imaging when compared with obliteration. It should be noted that this requires a reliable and compliant patient. Transnasal endoscopic surgery is not part of all craniofacial surgeons practices, which likely accounts for the delays in adapting transnasal endoscopic techniques into the management of frontal sinus trauma. However, observation followed by rescue endoscopic frontal sinus surgery if necessary has begun to be accepted as a safe method for managing select patients with nasofrontal duct injury Anterior Table Fracture and Cosmetic Deformities Fractures that occur as a result of frontal trauma almost always involve the anterior table to some degree. The main morbidity of these fractures comes from the destruction of the forehead contour, typically causing what appears to be a dent in the forehead. Addressing these contour deformities is not unlike most craniofacial surgeries aimed at restoring pretraumatic cosmesis, anterior table fractures are exposed, reduced, and rigidly fixated. This is accomplished via wiring or plating the fractured segments together. In cases of severe comminution with small bony fragments, a precontoured rigid mesh plate is often preferred so that multiple small fragments can be correctly arranged together. One of the risks of permanent implants is extrusion of wires and plates through the skin, and for this reason, some surgeons prefer absorbable mesh for the fixation of fractures. The drawback to absorbable material is the lack of long-term rigid support provided by wires, titanium mesh, and miniplates. It should be noted that extrusion of plates from the frontal sinus is uncommon, and in a study by Islamoglu et al, frontal sinus miniplates represented the smallest portion craniofacial miniplates requiring removal. Like any metal implant, rigidly fixating plates to avoid motion, plating in a clean field, and having healthy nontraumatized tissue overlying the implant are all thought to minimize the risk of extrusion. Balancing the risks of surgical exposure with the benefits of repair is paramount in anterior table repair and has led to the development of minimally invasive techniques. Traditionally, these fractures were approached with coronal incisions, and though these provide fantastic exposure, they also have been known to cause alopecia, paresthesias, unsightly scars, facial nerve injury, and temporal wasting. Without appropriate patient selection, cosmetic defects from coronal incisions may be worse than the defects from the trauma itself. These endoscopic techniques are similar to the endoscopic brow approach to the forehead. The main difference between endoscopic brow lifts and endoscopic anterior table repair is that only two 2-cm port incisions are made in the hair line on either side of the fracture instead of the typical four incisions seen in a brow lift. A small stab incision or lynch incision can be used to access the fracture for screw placement. Fractures can be reduced into place by a stab incision overlying the fracture allowing for the introduction of an elevator. If possible, the bony fragments are removed through a port incision and plated on the back table. Once replaced and inset into the defect, screws can then be placed through the stab incision. The main limitations of this approach are that it is limited to moderately displaced, simple fractures, and for those unfamiliar with endoscopic brow lift techniques, it has a steep learning curve. Transnasal reduction has also been attempted successfully utilizing frontal sinus instruments and balloon catheters to reduce fractures. This allows for an incisionless surgery, but this approach is further limited to simple, medially located fractures. More comminuted fractures will still require a coronal incision for repair. For fractures where the bone is extensively comminuted and unable to be put back together, autologous grafts such as iliac crest bone or split calvarial bone grafts can provide the best substrate to recreate the natural contour. When bone grafts are not available or the defect is too large, then synthetic materials such as methyl methacrylate, polyether ether ketone, hydroxyapatite cement, or porous polyethylene have been used. The down side to these synthetics is they can harbor infection, extrude, and then require repeat surgery for removal. Though there are a large variety of ways to reconstruct anterior table defects, it is important to remember that the least invasive and most cosmetic method that can satisfactorily reduce the defect is usually the method of choice. 65,77,86 89 References 1 Ghavami A, Pessa JE, Janis J, Khosla R, Reece EM, Rohrich RJ. The orbicularis retaining ligament of the medial orbit: closing the circle. Plast Reconstr Surg 2008;121(03): Gerbino G, Ramieri GA, Nasi A. Diagnosis and treatment of retrobulbar haematomas following blunt orbital trauma: a description of eight cases. Int J Oral Maxillofac Surg 2005;34(02): Chen YA, Singhal D, Chen YR, Chen CT. Management of acute traumatic retrobulbar haematomas: a 10-year retrospective review. J Plast Reconstr Aesthet Surg 2012;65(10): Hislop WS, Dutton GN, Douglas PS. Treatment of retrobulbar haemorrhage in accident and emergency departments. Br J Oral Maxillofac Surg 1996;34(04): Maurer P, Conrad-Hengerer I, Hollstein S, Mizziani T, Hoffmann E, Hengerer F. Orbital haemorrhage associated with orbital fractures in geriatric patients on antiplatelet or anticoagulant therapy. Int J Oral Maxillofac Surg 2013;42(12):