Traumatology and Traumatic Optic Neuropathy


Cause


Frequency


Falls


10–38%


Sports accidents


5–31%


Assaults


4–41%


Traffic accidents


12–59%


Work accidents


0.8–5%


Others


0.8–3%



Injury mechanisms are highly dependent on locoregional features. While in Innsbruck (Austria) and Grenoble (France) (winter) sports accidents are the primary cause, 5,​ 7 assault dominate in the United States and in Germany. 2,​ 3,​ 9 In Brazil, India, and the United Arab Emirates, traffic accidents are predominant (in UAE 5.5%, with camel participation), with falls and assault following in frequency in India and in Brazil, respectively. With a rate of 4%, assault is only rarely observed in the United Arab Emirates. 4,​ 6,​ 8 Since the 1980s, mid-facial injuries in car accidents have significantly declined in industrialized countries due to the statutory use of seat belts. This trend was reinforced by the introduction of airbags, explaining the shift of injury frequencies, with assault becoming the primary cause for trauma. 10,​ 11,​ 12 Seasonal influences are also reported. 13 Furthermore, with a ratio of 4:1 men are significantly more often affected than women. The median age is approximately 38 years. 14,​ 15,​ 16


In many cases, associated injuries of the skull base can be observed, necessitating a thorough medical history and physical examination. Since patients presenting orbital fractures have often suffered multiple traumas, it can be complicated to obtain an accurate history. 17,​ 18


8.2 Patient History


Depending on the patient’s vigilance, a direct or an indirect patient history should be sought. In either case, the following facts need to be collected:




  • Type of accident (fall, sports, work accident, assault).



  • Time and course of the accident.



  • Retrograde amnesia, loss of consciousness, and possibly duration.



  • Preexisting conditions and social history.



  • Principal complaints and impairment (e.g., loss of vision, diplopia),.



  • Limitations of daily routine due to symptoms.


8.3 Clinical Examination


First, a complete endoscopic ENT and ophthalmic examination is necessary (see Chapter ▶ 3). In comatose patients, a determination of visual evoked potentials can provide information on the functioning of the visual system. 19


8.4 Instrumental Diagnostics


If clinical examination does not reveal evidence suggesting a bone injury of the facial skeleton, occipitomental radiography of the sinuses is sufficient for a preliminary assessment. The suspicion of a nasal bone fracture indicates an additional lateral radiograph of the nose. Besides possible fracture lines, the occipitomental sinus radiograph reveals a blow-out fracture showing the typical image of a hanging drop (see ▶ Fig. 4.1).


If radiation exposure is contraindicated (e.g., in children or during pregnancy), sonography can supply valuable information, for example, on fracture lines in the osseous nasal framework or the infraorbital rim (see ▶ Fig. 4.42). 20


If the clinical examination or the subsequent occipitomental sinus radiograph suggests a fracture, a CT scan of the orbit as well as the paranasal sinuses should be performed. This provides information on the presence of fractures and accompanying bone injuries. Also, the extent of the fracture and the path of its fracture lines can only be determined using CT. 21


8.5 Symptoms


Fracture signs in the orbit and the midface, as in other bone injuries, can be classified as certain and uncertain signs ( ▶ Table 8.2). Certain fracture signs include crepitation of bone fragments, malposition (elevation), abnormal mobility, and presence of fracture lines in diagnostic imaging. Characteristics of uncertain fracture signs are swelling, soft tissue emphysema, diplopia, impairment such as a trismus, dysesthesia, and pain. Many patients report an initial epistaxis that usually stops without treatment. A black eye or periorbital hematoma is one of the major symptoms occurring shortly after trauma ( ▶ Fig. 8.1; see also ▶ Fig. 6.2). Trauma to the orbital floor causes a descent of the eyeball, resulting in consecutive enophthalmos. Double images stem from eye motility disorders that might be caused by swelling or by an incarceration of extraocular muscles in the fracture gap; for example, of the inferior rectus muscle. Depending on the affected muscle, diplopia is reinforced when gazing up or laterally. Additionally, a traction test in this case is pathologic.
































Table 8.2 Certain and uncertain fracture signs in orbital and midfacial fractures

Certain fracture signs


Uncertain fracture signs


Crepitation of bone fragments


Swelling


Deformation (step formation)


Emphysema


Motility disorder


Diplopia


Diagnostic imaging


Functional disorders (e.g. trismus)



Sensory disturbance



Dental percussion attenuation



Pain




978-3-13-199421-9_c008_f001.tif


Fig. 8.1 Patient with monocular hematoma in LeFort III fracture (bilateral) and Escher IV fracture (right).



Trauma often leads to shearing injuries around the infraorbital nerve canal but only rarely to ruptures. A result is sensory loss in the supply area of the infraorbital nerve (terminal branch of the maxillary division of the trigeminal nerve, V2). Traumatic optic neuropathy (TON), which occurs in up to 5% of all craniocerebral injuries and facial trauma, leads to a loss of vision. In unconscious patients, this can be diagnosed by a missing pupillary response (afferent pupillary defect). 22 With endonasal pressure increase (e.g., on nose blowing or pressing) the size of hairline cracks is sufficient to allow air to enter the surrounding tissue of the paranasal sinuses. Emphysema in the area of the upper and lower lid with corresponding crackle is the first indication, but it might also spread over the entire affected side of the face ( ▶ Fig. 8.2). Other symptoms mentioned in ▶ Table 8.3 depend on associated injuries.



978-3-13-199421-9_c008_f002.tif


Fig. 8.2 Patient presenting pronounced air emphysema of cheek soft tissue in an orbital floor fracture on the left and nasal bone fracture (axial CT scan).
































Table 8.3 Other symptoms of orbital fractures, caused by associated injuries

Symptom


Associated injury


Malocclusion


Zygomatic bone fracture, LeFort fracture


Drawer effect


LeFort I–III fracture


Rhinoliquorrhea


Skull base fracture


Meningitis


Skull base fracture


Intracerebral air inclusions


Skull base fracture


Hematoma of the septum


Lesion of the septum


Anosmia


Degloving of the olfactory glands


8.6 Orbital Soft Tissue Injuries


Soft tissue injuries of the orbit may occur in isolation or in combination with bone injuries. These especially include eyelid and bulbar injuries.


Due to the possibility of contamination, tetanus protection must always be secured. In inconclusive cases or those that are not in line with general vaccination recommendations (currently every 10 years for adults), simultaneous vaccination with tetanus immunoglobulin and active vaccine must be applied. 23 For animal bites, postexposure immunoprophylaxis against rabies might be indicated.


8.6.1 Lacerations


Various injury patterns can be distinguished. Accidents mostly produce tear crush wounds with lacerated edges and occasional tissue defects. Abrasions are also common in accidents. Cuts, in contrast, are characterized by sharp and mostly well-adapting wound rims. Bite wounds in the facial area are rather rare. 24,​ 25


Wounds should be cleaned immediately and examined for associated injuries. Depending on the size of the wound and the patient’s consent, this can happen during the initial examination or under general anesthesia. To achieve optimal healing, wounds should be treated within 8 hours after trauma (the so-called 8-hour rule). It is important to ensure that the wound is closed tissue layer by tissue layer, without application of tension. Monofilament suture sized 5–0 or smaller is recommended to decrease the risk of further damage and to produce a cosmetically favorable scar. To avoid distortions due to scar tissue, rim adaptation should be as accurate as possible. Tension lines to the skin should be monitored.


8.6.2 Orbital Foreign Bodies


In leisure accidents but also in work- and sports-related accidents (in this case also in gunshot wounds) foreign bodies enter the orbit. Accidents at work mostly involve splinters of various materials (especially metal and glass), while leisure accidents often involve pieces of wood (see ▶ Fig. 4.6). 26,​ 27,​ 28 Depending on the material and size of the foreign body, extensive bulbar damage may occur despite very small entry wounds. Particularly in children, there are reported cases in which the foreign matter was found only after lengthy diagnostics (see Chapter ▶ 4). 29,​ 30


Treatment always involves surgical removal of the foreign body under general anesthesia. The removal of the whole of the foreign material must be ensured and orbit, eye, and skull base have to be inspected for associated injuries. In order to better localize the foreign body, surgical removal should be carried out using a computerized navigation system where possible. 31 The use of a magnet is helpful in the removal of metallic objects. Only in a very few cases, and only if a complete removal of metallic material involves a threat to patient’s eyesight, can pieces be left in place. 32 Very pronounced orbital trauma with associated optic nerve injury, penetrating bulbar injury, or puncturing of the skull base may occasionally necessitate enucleation.


Complications and sometimes initial symptoms of intraorbital foreign bodies are orbital edema, cellulitis, and abscess, as well as meningitis and brain abscess in the case of skull base fractures. 33


8.7 Orbital Wall Fractures


8.7.1 Medial Orbital Wall Fracture


Pathogenesis


The medial orbital wall is formed by the lamina papyracea, which separates the orbit from the ethmoidal cell system. As the name suggests, this is a paper-thin wall that fractures easily with only small force.


Symptoms


Medial orbital wall fractures present initial, self-limiting epistaxis. Since usually neither eye muscles nor periorbita are subject to incarceration, motility is preserved. Enophthalmos is generally mild but can lead to distracting diplopia.


Diagnostics


On suspicion of an isolated medial orbital wall fracture a CT scan is required alongside a clinical examination in order to rule out concomitant fractures.


Treatment


An isolated fracture of the medial orbital wall usually requires no treatment as patients are mostly symptom free. However, to avoid complications such as orbital emphysema the patient should refrain from nose blowing and physical activity.


Persistent diplopia due to enophthalmos or a cosmetically unacceptable enophthalmos can be treated surgically. In minor defects, the fracture piece can be endoscopically rotated and wedged. 34 If this fails, open surgery is necessary, for example, following the fronto-orbital approach based on Killian or the pericaruncular approach, or even endoscopically. Orbital contents can be supported by inserting absorbable materials such as PDS (polydioxanone) foil or copolymer plates made of D-lactic acids, L-lactic acids, and trimethylene carbonates 35 and also by inserting nonabsorbable material such as titanium mesh. 36


8.7.2 Lateral Orbital Wall Fracture and Zygomatic Fracture (Lateral Midfacial Fracture)


Pathogenesis


Fractures of the lateral orbital wall and the zygomatic bone are caused by the impact of lateral and frontal forces. Isolated fractures of the lateral orbital wall are rather rare. This can be explained by the anatomy of the midface: To ensure the “lightweight” nature of the midface and sufficient stability at the same time, bony buttresses between a cavity system with thin bone lamellae are the force-absorbing elements ( ▶ Fig. 8.3). They aid the transmission of chewing forces onto the skull base as well as the absorption of external forces. The lateral orbital wall forms one of these pillars, explaining why heavy forces are necessary to cause a fracture in this area. If forces are sufficient to cause a fracture of the lateral orbital wall, further fractures of midfacial pillars are usually associated. In almost every case this includes the cheekbone. For anatomical reasons, the lateral orbital wall often exhibits destruction of the frontozygomatic structure instead of a fracture. Classification of fractures of the zygomatic bone is based on Becker and Austermann ( ▶ Table 8.4).



978-3-13-199421-9_c008_f003.tif


Fig. 8.3 Pillars of the midface (according to Schilli, 1980 37).





























Table 8.4 Classification of zygomatic fractures according to Becker and Austermann 38

Classification


Type of fracture


I


Isolated zygomatic arch fracture


II


Nondislocated zygomatic bone fracture


III


Dislocated zygomatic bone fracture without diastasis at the lateral orbital rim




  • With medial rotation.



  • With lateral rotation (antral impaction).


IV


Dislocated zygomatic bone fracture with diastasis at the lateral orbital rim




  • With medial rotation.



  • With lateral rotation.



  • With dorsocaudal shearing.


V


Comminuted zygomatic bone fracture


VI


Type II–V fractures with fracture of the orbital floor



Clinical Examination


In addition to the typical hematoma and emphysema, which show significant decline starting around the third day after trauma, a disorder of mouth opening is an uncertain sign of fracture. While crepitation is usually not palpable due to the wedging of fragments, certain fracture signs often present palpable steps or diastases in the area of the zygomatic arch, the infraorbital rim, or the lateral orbital wall.


Radiological Imaging


CT imaging of both orbits as well as the midface is the diagnostic method of choice ( ▶ Fig. 8.4). In addition to the exclusion of a central midfacial fracture, the orbital floor can also be evaluated by CT. For an assessment of the zygomatic bone, especially if CT is contraindicated, sonography can be helpful. Discontinuities in the zygomatic arch and the zygomatic body as well as the lateral wall of the orbit can be detected sonographically. 20 A detailed sonographic localization of the fracture may be helpful even in cases of pronounced swelling and fracture steps that are not palpable, in order to support the planning of surgical treatment (determination of exact fracture location, length of fracture line). 39




978-3-13-199421-9_c008_f004.eps


Fig. 8.4 CT scan with representation of an intrusion fracture on the right lateral midface: (a) coronal, (b) axial.




Therapy


Treatment depends on patient’s symptoms, which require either clinical examination or CT imaging ( ▶ Table 8.5).



























Table 8.5 Decision algorithm for lateral midfacial fracture treatment

Conservative treatment


Surgical treatment


Mouth opening and closing possible


Trismus


Unrestricted bulb motility


Diplopia/impaired eye bulb motility


Isolated sensitivity disorders


Cosmetically problematic enophthalmos


Nondisplaced fractures


Flattened facial contour


Any displaced fracture


Diastasis



Conservative Fracture Treatment

Conservative treatment is indicated for nondisplaced fractures without formation of diastasis (type II) and complete preservation of function. Since the masseter muscle is attached to the zygomatic bone, causing caudal tension, additional tensile forces should be minimized to prevent defective healing with formation of a pseudarthrosis. To this end, detailed patient instructions on behavior (a soft diet, abstinence from sports, and entirely refraining from nose blowing) and consistent adherence to these is required for at least 6 weeks. There should also be regular, specialized medical checks to detect defective healing at an early stage and to initiate secondary surgical care where needed.


Surgical Fracture Treatment

Once a dislocation or impairment is present, surgical treatment is required within one week after trauma as already incipient healing processes can significantly complicate repositioning at a later stage. Depending on the type of fracture, surgery can be either percutaneous or open.


Percutaneous repositioning can be performed in type III fractures, classified according to Becker and Austermann (see ▶ Table 8.4). For this purpose, a skin incision is made approximately 4 cm below the lateral orbital rim through which the orbit is entered using a single hook, inserted below the cheekbone, which is then repositioned under palpatory control. The zygomatic bone is securely reduced without osteosynthesis because fracture pieces are usually wedged together due to their often jagged edges. A similar procedure can be used in isolated zygomatic arch fractures (type I classification according to Becker and Austermann). Here, the single hook is directed through a small incision below the zygomatic arch to reach under the fracture pieces, which are then repositioned under application of slight tension. Another method for re-positioning an isolated zygomatic arch fracture includes using a small incision in the oral vestibule. The fractured zygomatic arch is usually dislocated in an M-shaped manner ( ▶ Fig. 8.5). Via this access point, an elevator is positioned underneath the fracture pieces to lift them upward. The same procedure is carried out in the Gillies approach with incision at the temporal hairline and following cranial elevation of the zygomatic arch ( ▶ Fig. 8.6). 40



978-3-13-199421-9_c008_f005.tif


Fig. 8.5 Axial CT with representation of an isolated M-shaped zygomatic fracture (left).



978-3-13-199421-9_c008_f006.eps


Fig. 8.6 Gillies approach for zygomatic fracture repositioning. Incision along the hairline and insertion of an elevator underneath the temporal fascia to the zygomatic arch. (Reproduced from Welkoborsky HJ. Traumatology. In: Strutz J, Mann W. eds. Practice of Otolaryngology, Head and Neck Surgery. Stuttgart: Thieme; 2009.)



As in all percutaneous procedures, surgeons need to ensure that fractures are set in the correct position and remain stable. When destabilization of the fracture is observed, fixation through a small osteotomy is required. Patients must follow the same instructions as in conservative fracture treatment.


If there is no possibility for intraoperative radiography, positioning can be controlled using ultrasound. 39


In all other cases, open repositioning is indicated. Here, the infraorbital plate is exposed through transconjunctival or subciliar incision, the lateral orbital wall via an incision in the lateral eyebrow considering skin tension lines, and the zygomatic arch, if necessary, through an incision above the fracture itself. In order not to jeopardize the zygomatic and temporal branches of the facial nerve, surgery with neuromonitoring of the facial nerve is recommended. Subsequently, repositioning can be performed under direct vision followed by osteosynthesis with mini-plates. This approach also offers the possibility of inspecting the orbital floor and medial orbital wall and, if necessary, treatment of the same ( ▶ Fig. 8.7). Surgical exposure of the zygomatic arch should only be carried out if it is not properly adjusted after repositioning.



978-3-13-199421-9_c008_f007.eps


Fig. 8.7 Open surgical treatment of a lateral midface fracture. (a) Incision at the lateral eyebrow and subciliar incision. (b) Fixation with mini-plates. (Reproduced from Welkoborsky HJ. Traumatology. In: Strutz J, Mann W. eds. Practice of Otolaryngology, Head and Neck Surgery. Stuttgart: Thieme; 2009.)



In all surgical procedures, postoperative repositioning control using radiographic close-ups of the sinuses (see ▶ Fig. 4.2) and recording of the zygomatic arch in lateral projection is mandatory ( ▶ Fig. 8.8).



978-3-13-199421-9_c008_f008.eps


Fig. 8.8 Radiographs for repositioning control of the zygomatic arch. (a) Free repositioning of the zygomatic arch on the left side without osteosynthesis. (b) Treatment using mini-plate osteosynthesis on the left side.



Complications


Complications of fractures of the zygomatic bone and zygomatic arch include infection, trismus, and emphysema as well as ophthalmic, neurogenic, and postoperative complications (see ▶ Table 8.6).













































Table 8.6 Complications of zygomatic bone and zygomatic arch fractures

Ophthalmologic complications


Neurogenic complications


Postoperative complications


Other


Exophthalmos


Sensory deficits in the supply area of the infraorbital nerve


Intraorbital bleedings


Infections


Bulbus depression


Neuralgic pain


Bulbus injuries


Trismus


Proptosis



Ectropion


Soft tissue emphysema


Loss of vision



Keloid formation (rarely)



Motility disorders





Orbital emphysema






8.8 Isolated Orbital Floor Fractures


8.8.1 Blow-out Fracture


Pathogenesis


In isolated orbital floor fractures, external force is usually not sufficient to impair the midface buttresses. Forces are transmitted to the parchmentlike orbital floor, leading to an isolated fracture in this area. Since fractures of the orbital floor usually continue into the maxillary sinus and bone fragments are often found there, they are also referred to as blow-out fractures. There are two origination theories for the fracture mechanism 41:




  • The hydraulic theory ( ▶ Fig. 8.9a) suggests a direct effect of force on the globe with closure of the orbit, where the bulb can only be displaced into the orbit. Here, orbital tissue serves as a form of hydraulic system. Since energy cannot escape otherwise, it fractures the weakest bone—the orbital floor. This is a typical mechanism, acting, for example, when a tennis ball directly strikes the eye.



  • If force acts directly on the infraorbital rim, without resulting in fracture (e.g., in a blow or fall), energy is transmitted from the bone straight to the orbital floor, which cannot withstand the force, causing an isolated fracture. This mechanism is referred to as bone transmission (buckling) theory ( ▶ Fig. 8.9b).



    978-3-13-199421-9_c008_f009.eps


    Fig. 8.9 Formation mechanisms of blow-out fractures. (a) Hydraulic theory. (b) Buckling theory. (Reproduced from Welkoborsky HJ. Traumatology. In: Strutz J, Mann W. eds. Practice of Otolaryngology, Head and Neck Surgery. Stuttgart: Thieme; 2009.)



In the literature, the occurrence rate of isolated orbital floor fractures in midface fractures is reported to be 11 to 13%. 11,​ 42 Orbital involvement, particularly in cheekbone fractures, is observed in about 24% of cases. 2,​ 43


Investigative Imaging


On suspicion of an isolated orbital floor fracture or in cases representing a pendant drop in the occipitomental sinus radiograph (see ▶ Fig. 4.1), CT imaging is indicated, primarily to exclude further fractures. It also serves preoperatively in the determination of the fragment size and thus the planning of treatment. Despite coronary, axial, and sagittal stratification, the fragment size cannot always be determined conclusively in two-dimensional representation ( ▶ Fig. 8.10). 3D reconstruction can be helpful for this purpose. In very large orbital floor fractures, the opposite orbital floor can be preoperatively mirrored onto the injured side using CT navigation in order to produce a precisely shaped titanium mesh ( ▶ Fig. 8.11), as reconstruction can be controlled using the mirrored image. 44,​ 45



978-3-13-199421-9_c008_f010.eps


Fig. 8.10 CT scan of an isolated orbital floor fracture on the right: (a) sagittal stratification; (b) coronary stratification.



978-3-13-199421-9_c008_f011.tif


Fig. 8.11 CT navigation, mirroring the healthy orbital floor (right) onto the left fractured side.



Complications


Orbital floor fractures are often accompanied by complications common with paranasal sinus system involvement—namely, sinusitis. Also, pathogens may ascend from the paranasal sinuses leading to orbital cellulitis and abscesses. Furthermore, air can be forced out of the maxillary sinus into the orbit—a cause of emphysema. 46


When a repositioning that is indicated is not carried out, the results are often cosmetically relevant enophthalmos, diplopia due to bulbar motility, disorders, and pseudoptosis, all of which may permanently affect the patient.


Since the fracture often involves the infraorbital nerve canal, one of the most common complications is sensory disturbance in the supply area of the infraorbital nerve, which patients get used to fairly quickly even though it may persist after surgical treatment. In most cases, sensory disturbances largely regenerate within 3 months. 47 Preoperative cases of sensory disturbance are described in 10 to 82% of cases. In a postoperative interval of 3 to 6 months, sensory disturbances are observed in only 8 to 25% of patients. 1,​ 48,​ 49,​ 50,​ 51


Therapy


Decisions regarding conservative therapy should be based on the following criteria: absence of ocular symptoms (diplopia, enophthalmos), unbalanced risk–benefit ratio, or exclusive sensitivity disturbances ( ▶ Table 8.7). This specifically applies to elderly patients with increased intraoperative risk due to preexisting cardiovascular conditions as well as to patients suffering from dementia. 52 In either case, incarceration of the orbital muscle (inferior rectus muscle) must be prevented.




















Table 8.7 Decision algorithm for the treatment of isolated orbital floor fractures

Surgical treatment indicated


Conservative treatment possible


Diplopia


Exclusive sensitivity disorders


Exophthalmos


Multi-morbid patients


Major defects




All other cases should be subject to surgical treatment. Incarceration of the inferior rectus muscle indicates treatment within 24 hours, as otherwise fibrosis occurs. 53 In all further cases surgery should be delayed until an accompanying swelling has decreased, guaranteeing notably improved interoperable visibility. Nevertheless, definitive surgical treatment must be carried out within 7 to 10 days following the trauma.


If surgical treatment is required, a transconjunctival or subciliar access to the orbital floor is recommended (see Chapter ▶ 18). In a subciliar access, the orbicularis oculi muscle is sought and forced apart, presenting the adjacent (intact) infraorbital rim. Now, eyeball and periorbita are pushed aside cranially. Prolapsed parts (periorbita, periorbital fat or possibly muscles) are then gradually removed from the fracture line and the fractured pieces are repositioned. Depending on the size and type of the fracture, its pieces are wedged into the orbital floor . After wedging the fragment of the fractured piece with the orbital floor, the contents of the orbit can be carried by this layer. In many cases this is not possible, requiring the bypassing of the defect. In small residual defects, endogenous material of the temporal fascia can be used, 54,​ 55 but collagen membranes can also be used in fractures <1 cm2. 56 However, neither is stable enough to support the orbital content in larger defects. In such cases, a piece of PDS (polydioxanone) film is placed on the fracture edges ( ▶ Fig. 8.12). 57 Those edges are no longer sufficient as a supporting surface if the orbital floor is almost completely broken away. If this is the case, preformed titanium mesh can be used for reconstruction ( ▶ Fig. 8.13). 58 Here CT navigation mirroring the nonfractured orbital floor onto the traumatized side facilitates the localization of the correct position for the mesh ( ▶ Fig. 8.11). 44 Inserted material rarely causes problems and can therefore usually be left in place. 59



978-3-13-199421-9_c008_f012.eps


Fig. 8.12 Surgical treatment of an orbital floor fracture. (a) Subciliar incision and displacing of the orbicularis oculi muscle. (b) Insertion of PDS foil. (Reproduced from Welkoborsky HJ. Traumatology. In: Strutz J, Mann W. eds. Practice of Otolaryngology, Head and Neck Surgery. Stuttgart: Thieme; 2009.)

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Oct 26, 2019 | Posted by in OTOLARYNGOLOGY | Comments Off on Traumatology and Traumatic Optic Neuropathy

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