Ophthalmic Injuries

I. Introduction

A.

Eye injuries are common and require prompt evaluation and treatment to minimize the risk of loss of sight. These injuries may be obvious (as with penetrating trauma) or more subtle, yet still sight threatening. Additionally, competing injuries and altered responsiveness can hinder early ophthalmic assessment.

B.

Prompt consultation with an ophthalmologist is recommended when either clear ocular injury exists or any suspicion of injury exists. Patients with periorbital or ocular trauma may have sight-threatening injuries with little superficial evidence, only to be discovered by an exam by an ophthalmologist.

II. History

A.

Obtain as complete a history as possible of the injury. What type of object (e.g., ball, metal, etc.) hit the eye? Was it thrown or hit by a bat, and from how far away?

B.

Obtain a history of preexisting ocular disease. Does the patient normally wear eyeglasses? Is there a history of ocular surgery or previous trauma?

C.

Was the patient wearing eye/face protection?

D.

What are the patient's complaints? Specifically, ask if there a change in vision, pain, photophobia, or other new visual symptom or change (such as floaters or sensation of a curtain obscuring the vision).

III. Physical Examination

A. Visual acuity is the “vital sign” of the eye

Regardless of how minor an injury may appear, documentation of visual acuity is the first step in evaluation of any patient with possible ocular trauma. In general, the ultimate visual outcome is directly related to the presenting visual acuity.

• Test each eye separately for vision by covering the opposite eye with either the palm of the patient's hand or an occlusive device.
  • In the emergency setting, patients are often supine. A description of the ability to see letters on a card, a pen, or name tag is sufficient. In the case of a patient with reduced vision, the distance at which the patient can count fingers, see a hand wave, tell the direction of a light (light projection), or detect the presence of a light (light perception) provides an adequate preliminary assessment.
  • If the patient has eyeglasses, check visual acuity with them in use. For older patients with bifocal glasses, test near vision with the patient looking through the bifocal portion at the bottom of the glasses.
    • If the glasses have been lost or are not with the patient, a pinhole device (in a piece of paper or cardboard or a commercial device) may be used to approximate corrected vision.
    • Documentation in the medical record of “vision intact,” “vision okay,” “fine,” or “the same” is inadequate.
• Test pupillary reactivity and compare one pupil to the other. Note the shape and reactivity. Documentation of the presence or absence of a relative afferent pupillary defect (RAPD) is important in characterization of injury.
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  • RAPD refers to a difference in reactivity of the pupils when a bright light is swung briskly from one eye to the other. The affected pupil will react less strongly, not at all, or perhaps even dilate when presented with the same light as produces a normal constriction of the unaffected pupil. Presence of an RAPD indicates serious optic nerve or ophthalmic damage, as it is a bulk response of the visual apparatus. Absence of an RAPD indicates no significant optic nerve damage or bilateral optic nerve damage (note, however, that in its absence severe eye injury may still be present).
• Obtain visual field evaluation by confrontation testing (asking the patient to count fingers in all four quadrants of each eye separately) and document whether the patient is cooperative enough to undergo the test (Fig. 21-1 and Table 21-1).
• Examine the extraocular movements and report any decrease or pain.
• Document the gross appearance of the eye: Does it appear to be intact and quiet? If further evaluation is possible, assess the following:
  • Eyelids. Assess for edema, laceration, ptosis, or other evidence of injury.
  • Palpate the orbital rim for deformity or crepitus.
  • Examine the globe without applying pressure. Assess the globe for possible displacement or entrapment, and describe the movement of the eye.
  • Conjunctivae. Evaluate for subconjunctival hemorrhage, chemosis (swelling), or foreign bodies.
  • Cornea. Assess for integrity, opacity, abrasions, foreign bodies, or contact lenses.
    • Contacts should be removed from trauma patients. If unsure whether a patient wears contact lenses, a small amount of fluores-cein will make the presence obvious. An unconscious patient can develop a perforating bacterial corneal ulcer from a contact lens left in the eye for several days.
    • Abrasions may be visualized with fluorescein instilled into the con-junctival sac. A cobalt blue light will cause bright yellow fluorescence of the injured area.
  • Anterior chamber. Using a light directed at varying angles (direct and from side), assess for blood (hyphema) or abnormal depth. A shallow anterior chamber can result from an anterior penetrating wound, and a deep anterior chamber from injury to the posterior portion of the globe. A slit lamp exam is ideal for anterior chamber and corneal evaluation but can be impeded in immobilized or severely injured patients.
  • Iris should be reactive and the pupil should be round.

    Figure 21-1. Documentation of visual acuity.

    TABLE 21-1 Documentation of Pupillary Responses
    PERRL-APD Normal pupil responses to light, negative afferent pupillary defect

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  • Lens should be in the normal location and transparent. A dislocated lens will often be apparent only because the edge will be visible in the pupil.
  • Vitreous should be transparent. Blood in the vitreous will obscure the normal red reflection of the slit lamp or ophthalmoscope light from the retina. Assess for foreign bodies.
  • Retina. Assess for hemorrhage or detachment. Use of an ophthalmoscope with papillary dilation limits the amount of retina visualized and ability to detect noncentral lesions. Again, a dilated exam using magnification performed by an ophthalmologist is ideal, but sometimes impractical in the severely injured patient. Dilating agents should be used only with ophthalmolic and neurosurgical input, given the potential impairment of the exam and potential complications in certain settings (e.g., open globe or elevated intraocular pressure).

IV. Common Injuries

A. Chemical injury

Most ophthalmic injuries are unaffected by a short (minutes to an hour) delay in diagnosis. In contrast, chemical injury is a true ocular emergency, with care in the first minutes altering the outcome. A patient with chemical exposure to the eye must be irrigated copiously with saline (liters of normal saline connected to IV tubing with the needle end removed works well). Usually 15 minutes of constant irrigation is necessary before further exam should take place. The nature of the chemical is important in prognosis and further treatment. However, the specific nature is irrelevant in the first 15 minutes and all injuries should be irrigated with saline or water. Do not attempt to neutralize any acid or base by additions to the irrigating fluid.

B. Open globe

An open globe is the most serious sight-threatening ocular injury occurring in blunt maxillofacial trauma. It refers to a laceration or rupture of the eye wall with extrusion of intraocular contents.

• With a suspected open globe, immediately place a rigid shield over but not touching the eye and consult an ophthalmologist. Never place pressure or drops on the globe. Even slight pressure can cause extrusion of intraocular contents and reduce the chance of restoring useful vision or avoiding enucle-ation. This includes the pressure exerted by the eyelids in a forced squeeze, local anesthesia injection into the periocular region, or inadvertent pressure while closing lacerations on the face.
• Prehospital care of a suspected open globe involves protecting the eye with a plastic or metal shield taped from the forehead to the cheekbone.
• Additional maneuvers that may help save sight include administration of pain medication and antiemetics if needed to avoid grimacing and Valsalva.
• An ophthalmologist should perform ocular explorations under general anesthesia without local anesthetics.
• The most common rupture site for an open globe is at the limbus, the junction between the cornea and sclera. The second most common site for a scleral laceration is just posterior to the insertion of the four recti muscles.
• Signs that suggest a ruptured globe include:
  • Any distortion of the front of the eye
  • Loss of vision
  • Displaced lens
  • Traumatic hyphema
  • Hemorrhagic chemosis (hemorrhagic swelling of the conjunctivae, generalized or localized)
  • Shallow or deep anterior chamber
• After the initial evaluation, obtain a computed tomographic (CT) scan of the orbit.
• In the emergency department, prophylactic intravenous (IV) antibiotics, usually a cephalosporin, are started. Wounds contaminated with soil or dirt require clindamycin to prevent Bacillus cereus endophthalmitis.

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C. Traumatic hyphema

This denotes blood in the anterior chamber of the eye, which can obscure the detail of the iris or lens. A hyphema may be associated with a more serious injury (e.g., a ruptured globe). The hemorrhage will be visible as a layer or wisps of red blood. A microhyphema is suspended red blood cells without layering, visible only with a slit lamp.

• Any hyphema is treated with the following:
  • Rigid shield to the affected eye
  • Bed rest with the head elevated
  • Avoidance of aspirin and other NSAIDs
  • Dilation/cycloplegia (e.g., atropine 1% three times daily)
  • Topical anti-inflammatory (e.g., prednisolone acetate 1% 4–6 times daily)
  • Serial examinations with intraocular pressure checks by an ophthalmologist for at least the first 5 days postinjury
• Order a sickle screen if the patient is African American.
• Consider imaging studies to disclose associated injuries.
• Most patients with microhyphemas and small hyphemas are treated as outpatients (Table 21-2). Patients with larger hyphemas, other periocular trauma, and sickle-cell trait usually are treated as inpatients (Table 21-3).

D.

Intraocular foreign bodies (IOFBs) may be present despite excellent visual acuity. Small metallic fragments can enter the eye without the patient experiencing much discomfort. These metallic pieces are often <1 mm in diameter and can be multiple. Consider these in any eye injury, especially in a patient with a history of metal-on-metal hammering. The most useful imaging test is a high-resolution, thin-cut CT scan through the globe. Obtain axial and coronal views. Small IOFBs can indicate that other ocular injuries are present, and a detailed ophthalmologic examination must be performed. Surgical removal is usually accomplished by vit-rectomy (Table 21-4).

E. Corneal abrasions

Abrasions are common and cause pain, tearing, a foreign body sensation, photophobia, and decreased visual acuity. Fluorescein will stain the corneal abrasion bright yellow when viewed with a cobalt blue filter.

• Superficial corneal foreign bodies can be removed with irrigation. If the foreign bodies are embedded in the cornea, refer the patient to an ophthalmologist, after instilling ophthalmic ointment in the eye.
• Patching the eye may be dangerous as it allows bacteria in dirty abrasions to multiply, and has not been shown to increase comfort.
• Any abrasion should be treated with application of ophthalmic antibiotic ointment at least once daily until the epithelium is healed. Refer the patient to an

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  ophthalmologist for follow-up, and counsel the patient to seek immediate treatment if symptoms persist for more than 24 hours, or if a central abrasion or defect larger than 2 mm is detected.

  TABLE 21-2 Outpatient Management of Hyphema

  Medications —Atropine 1% three times daily —Prednisolone acetate 1% one drop four times daily —Topical antibiotics, if epithelial defects are present —Acetaminophen—no aspirin or nonsteroidal anti-inflammatory drugs —Acetazolamide or beta-blocker if intraocular pressure is elevated Activities —Bed rest with head elevated —Limited activity—no bending, lifting (straining) —Shield over injured eye Follow-up —Seen daily for 4–5 days

  TABLE 21-3 Inpatient Acute Management of Hyphema

  Medications —Atropine 1% three times daily -Prednisolone acetate 1% four times daily —Antiglaucoma medication: timolol maleate 0.5% twice daily, acetazolamide 500 mg twice daily —Acetaminophen for pain: as needed -Aminocaproic acid (50 mg/kg liquid every 4 hours; maximum dose 30 g/24 hours) Activities —Bed rest with bathroom privileges and decreased activity -Shield full time to injured eye Indications for surgery —Blood staining of the cornea —Elevated intraocular pressure of 50 mmHg for 5 days, 35 mmHg for 7 days, or eight ball hyphema. In patients with sickle cell, surgery recommended with intraocular pressure over 24 mmHg for 24 hours on maximal medications.

  TABLE 21-4 Intraocular Foreign Bodies Evaluation
  Visual acuity Dilated fundus examination Shield Computed tomography scan Operating room

F. Eyelid lacerations

Perform an ophthalmic examination on every patient with eyelid lacerations, and consider this for lacerations around the orbits (in general, the closer to eye, especially if any symptoms, the more detailed the exam). Soft-tissue injuries are repaired only after globe injuries are excluded and imaging studies performed. Even the most complex eyelid laceration repairs can be delayed for 24 to 48 hours with excellent surgical results.

• Specific eyelid complications include canthal tendon disinsertion, lacrimal drainage system (canalicular) lacerations, and levator aponeurosis laceration. These and transmarginal eyelid lacerations require special attention.
• Any laceration in the medial aspect of the eyelid, particularly if caused by a tearing injury, is likely to cause a canalicular laceration. Careful inspection, probing, and irrigation of the lacrimal apparatus are required to detect this injury. Irrigate and examine all wounds for the presence of foreign bodies.
• Complicated injuries and pediatric patients are best repaired in the operating room under monitored sedation or general anesthesia. Most superficial lacerations can be repaired with local eyelid blocks in the emergency department. In severe eyelid disruptions, the medial canthus should be addressed first with repair of the canalicular injury, silicone intubation of the lacrimal system, and repair of the deep head of the medial canthal tendon before closure of any

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  other eyelid lacerations. These are best repaired by an ophthalmologist or plastic surgeon skilled in lid repair, in a procedure room or operating room.
• Lacerations of the eyelid margin require a two-layered closure with 6–0 absorbable sutures in the deep tissue and nonabsorbable sutures in the eyelid margins (6–0 silk or 8–0 silk). Take care when closing deep eyelid tissue— never place sutures in contact with the surface of the eyeball.
• Superficial skin closure is best accomplished with 7–0 or 8–0 monofilament or chromic gut sutures.
• Ptosis secondary to the trauma is best observed for 6 to 12 months and then treated by a levator resection or advancement. Mechanical ptosis from hematoma or tissue edema usually improves slowly.
• Topical antibiotic ointments offer bacterial prophylaxis and corneal protection in circumstances of poor eyelid closure. Ice packs and nondependent head positioning are important posttreatment maneuvers.
• Avoid occluding the eye with pressure patching because of the risk of orbital hemorrhage. Check vision and pupils at regular intervals. The skin sutures usually are removed in 4 to 5 days. However, leave lid margin sutures in place 10 to 12 days.

G. Hemorrhage and orbital bone fractures

Orbital fractures can lead to acute, compressive orbital hemorrhage, an ophthalmologic emergency. The increasing intraorbital pressure resulting from an expanding hemorrhage can quickly lead to vascular compromise of the retina and optic nerve, resulting in permanent vision loss. Timely decompression with a lateral canthotomy and cantholysis can save vision in an eye with an expanding orbital hemorrhage.

• Of orbital fractures, 40% are associated with serious ocular injuries, including retinal tears and detachments, retinal hemorrhage, vitreous hemorrhage, dislocation of the lens, hyphema, glaucoma, and traumatic cataract. Ocular injuries occur with midface, supraorbital, and frontal fractures. An open globe, retinal detachment, or traumatic optic neuropathy present contraindications to early bony repair. As a general guideline, fix the globe first. The bone can then be repaired in approximately 2 weeks.
• Elevated intraocular pressure suggests increased orbital pressure, whereas lower intraocular pressure suggests a penetrating or perforating injury with globe disruption. Recognition of these ocular injuries is essential. Repair of isolated orbital fractures is almost never an operative emergency, and a complete ocular evaluation should be done before any orbital bone surgery.
• Exception to this rule occurs in young patients who have greenstick fractures (trapdoors) of the orbital floor with inferior rectus entrapment. These patients often have a relatively white, quiet-looking eye, severe deficiency of upgaze, pain, and nausea. These must be repaired in the operating room as soon as safely possible, preferably within 24 hours.

H. Traumatic optic neuropathies

Traumatic vision loss with complete blindness occurs in approximately 3% of patients suffering blunt maxillofacial injuries. Of midface, supraorbital, or frontal sinus fractures, 4% are associated with severe optic nerve injuries. Early diagnosis and treatment of optic nerve injuries may minimize vision loss.

• With a greater number of patients with closed head trauma surviving, more surviving patients have permanent loss of vision. Decreased visual acuity or visual fields with an afferent pupillary defect in the involved eye indicates optic nerve injury. It is sometimes difficult for the nonophthalmologist to make this determination because multiply injured trauma patients are often uncooperative or unconscious. Additionally, the optic disc may appear normal on ophthalmoscopy. It is necessary to carefully examine the pupils to make the diagnosis of an afferent pupillary defect.
• Obtain thin-section CT scans through the orbit and optic canal to exclude the possibility of a bone fracture compromising the optic nerve.
• Treatment of optic neuropathy in this setting is controversial. Very high-dose steroids are of unproven benefit but occasionally used. These may be given if

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  not otherwise contraindicated, then discontinued after 3 days if no response occurs. A surgical optic nerve decompression may be performed if bone fragments appear to be compromising the canal, but is realistic only in the hands of an experienced surgeon.

I. Cataract

A blunt injury to the eye can result in clouding (cataract) or displacement of the lens. A sharp injury to the lens capsule can also cause a cataract, but lens particles can also leak into the anterior chamber, resulting in severe uveitis, lens-induced glaucoma, and sometimes lens anaphylaxis (severe inflammation from exposure to lens proteins). A leaking lens must be removed.

J. Retinal detachment

Blunt trauma can cause retinal detachment, especially in patients who are nearsighted, have had previous ocular injury, or have had cataract surgery.

• Most retinal detachments caused by trauma do not occur at the time of injury, but occur weeks to months later. Although the risk never drops to zero, most detachments occur within 6 months of injury.
• The diagnosis is suspected when a patient presents with complaints of flashing lights and a curtain or shade interfering with some portion of the visual field. Confrontation visual fields may detect the field loss. The diagnosis is made by indirect ophthalmoscopy through a dilated pupil.

K. Retina commotion

A finger or other object directly hitting the eye or orbit can cause retinal damage that has the appearance of edema around the optic nerve or macula on ophthalmoscopy. This is caused by a shearing injury of the retina, and recovery is usually quick (weeks) and complete. Blood may also appear under the retina. Recovery can be complete or very limited.

Axioms

• Determination of visual acuity is essential for early detection of serious eye injury.
• Sutures are never placed in direct contact with the globe.
• If an open globe is suspected, put no pressure on the eye and use no drops in the eye.

Surgical Management of Cervical Spinal Column Injuries

The timing of a surgical intervention remains debated. Data are accumulating in support of early (<3 days) surgery. Safety, decreased morbidity, shorter length of stay, and lower rates of pneumonia have been documented. There is no consistent evidence to show improved neurologic outcome.

A. Occiput C1 to C2 injuries

• Occipital C1 injuries are an uncommon but often missed injury. Otherwise known as atlantooccipital dislocation, these typically cause a disruption between the occipital condyles and C1. Patients who survive typically exhibit lower cranial neuropathies, mono/para/quadraplegia, and respiratory dysfunction, although 20% may have normal exams. Craniocervical subarachnoid blood or cervical prevertebral edema can provide an early clue to the diagnosis. Treatment involves craniocervical fusion with internal fixation.
• C1 to C2 injuries, which are common, are frequently missed because of the relatively complex anatomy of the C1-C2 junction and the difficulty in obtaining a full set of films in the multiply injured patient. The bony odontoid fractures can be divided into types I, II, and III (Fig. 18-4).
  • Type I fractures are oblique fractures through the upper portion of the odontoid process that can be managed with a rigid cervical collar. These are rare and often confused with os odontoidium, an isolated bony ossicle with smooth margins and no osseous connection to the body of C2. Os odontoidium likely represents an acquired nonunion of C2 secondary to prior trauma. This stable fracture can be managed with observation.
  • Type II fractures are those that occur at the base of the dens. These fractures are considered to be unstable in the acute setting, although most can be managed with external stabilization (rigid cervical collar or halo-vest device). Surgical intervention should strongly be considered in patients over 50 years old, after failure to achieve anatomic alignment with external fixation, with >5 mm dens displacement, or with significant comminution. Fractures with posterior displacement provide increased morbidity as they may impinge on the spinal cord. Surgical options include an odontoid screw, posterior fixation incorporating a Gallie-or Brooks-type construct, and transarticular screws. Airway management is critical in these patients
    

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    as upper airway swelling and subsequent respiratory compromise can occur (Fig. 18-5).

    Figure 18-4. Drawing of types I, II, and III odontoid fractures.

  • Type III fractures extend from the odontoid into the vertebral body of C2. They generally have a better healing rate than type II fractures with external fixation, and rarely need surgery.
• Jefferson fractures occur when an axial load is placed on the head. The C1 bone, which is circular in nature, is forced apart. Fractures occur anteriorly or posteriorly. Stability depends on the integrity of the transverse ligament as described below. A fracture with evidence of ligamentous disruption can be treated with a halo orthosis for 3 months or a C1-C2 fusion. Stable fractures can be treated with a rigid cervical collar for 2 to 3 months.
• It is important to consider that the main ligament stabilizing the dens within the ring of C1 is the transverse ligament. This ligament keeps the dens in close approximation to the ring of C1. The space between the posterior aspect of the ring of C1 and the anterior border of the dens is called the atlantodens interval. This space should not exceed 3.5 mm in the adult (Fig. 18-6).
  • The ligament can be torn whenever the ring of C1 is fractured. The amount of medial-lateral displacement of the ring of C1 can be measured on AP radiographs or CT reconstructions. Normally, the C1 lateral masses do not overlap the C2 vertebral body. Should the combined amount of lateral mass overlap of C1 on C2 exceed 6.9 mm, consider the transverse ligament to be torn and the C1-C2 area unstable (Fig. 18-7). MRI can also identify ligamentous injury or avulsion.
• Hangman's fracture refers to spondylolisthesis of the C2 pedicle. This type of fracture is also unstable and requires external fixation with a collar or halo vest, or rarely, internal fixation. Anterior C2-C3 fusion or posterior C1-C3 fusion should be
  

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  considered in cases of severe angulation, C2-C3 disc disruption, fracture/dislocation, or failure to achieve anatomic alignment with external fixation.

  Figure 18-5. Radiograph type II odontoid fracture.

B. C3 to C7 injuries

• Most of the C3 to C7 injuries can be diagnosed from a lateral film using the three lines to determine alignment and stability. On flexion and extension views, no >3.5 mm of listhesis should be seen between two vertebrae and no > 11 degrees of angulation between vertebral bodies, as measured at the adjoining endplates. The spinous process distances should be symmetric. CT will define the bone anatomy and MRI will better show the lig-amentous injury, cord anatomy, and disc pathology. In most injuries, both studies should be obtained. In all injuries requiring traction, delay in treatment reduces the chance of nonoperative reduction.

  Figure 18-6. Lateral radiograph demonstrating excessive atlantodens interval.

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• A common type of injury involves unilateral and bilateral facet injuries. These injuries include both fractures of the facet joints and injury to the capsules with resultant “perched” facets. Both types of injuries are noted on plain films and CT. The presence of 25% subluxation of one vertebra on another can represent a unilateral facet fracture or dislocation. The CT scan appearance of this fracture
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• has the appearance of “opposing hamburger buns” (Fig. 18-8). Subluxation of 50% generally means that a bilateral facet injury has occurred. Patients with these injuries should have MRI to diagnose any disc herniation that could interfere with reduction of the two vertebral bodies, potentially causing a neurologic catastrophe if the disc compromises the cord during reduction. Those patients may need anterior discectomy before reduction.

  Figure 18-7. C1 fracture with overhanging of the C1 lateral masses as seen on anteroposterior plain film (A) and axial computed tomography scan (B).

• Generally, unilateral and bilateral facet dislocations are reduced in tong or halo traction under close supervision by the spine surgeon. Awake reduction in a stable, alert patient with no distracting injury is both feasible and preferred. The reduction can also be performed intraoperatively with electrodiagnostic monitoring. A prereduction plain film or CT should be obtained to provide baseline anatomy. MRI should be obtained prior to reduction to rule out a ruptured cervical disc. Unilateral facet fractures can be stable, with pure bony injuries handled by halo-vest immobilization. An irreducible injury, ligamentous injury, >20% subluxation, or spinal cord compression necessitates anterior or posterior surgical fixation and possible decompression.
• Bilateral facet injuries are unstable because the spinal canal is generally severely compromised. Closed reduction with traction may be unsuccessful. Intraoperative reduction and surgical stabilization is the treatment method of choice if awake reduction fails. Once again, MRI is essential prior to reduction to prevent cord injury from a traumatically herniated disc.

C.

Burst fractures generally occur as a result of flexion or axial loading. The columns may appear well aligned at first glance on the lateral radiograph. Generally noted is an expansion of the prevertebral space and loss of vertebral height. The CT scan will show the vertebral comminution which can cause canal compromise and subsequent neurologic deficit. Fracture compression of 40% or more and subluxation of 20% or more indicate definitive instability. These will require surgical stabilization but should have gentle traction or collar immobilization during studies and before surgery.

D.

Teardrop fractures must be differentiated from the less ominous extension injury with a small fragment off the anterior cortex of the vertebral body. The true teardrop injury is highly unstable; CT will show the sagittal split in the vertebral body. MRI will often demonstrate an early spinal cord contusion. Most of these patients are neurologically impaired and will need surgery to stabilize the neck and decompress the spinal cord.

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Figure 18-8. Preoperative axial computed tomography scan demonstrating a unilateral jumped and locked facet fracture and dislocation (A). The left jumped facet has the appearance of two opposing hamburger buns (arrow). Anteroposterior (B) and lateral (C) radiographs demonstrating the instrumented fusion using lateral mass screws and rods with interspinous wiring and bone grafting.

E. Spinal cord injuries without radiographic abnormality (SCIWORA)

A number of patients will appear to be neurologically impaired without fractures or liga-mentous injuries noted on initial radiographic studies. Generally, patients in this group are at the ends of the age spectrum. Young patients are susceptible to this type of injury because of the elasticity of their ligaments. In the older patient, underlying degenerative or congenital cervical stenosis is usually found. Mild hyperflexion or hyperextension injuries will cause spinal cord compression without bony fracture. Early spinal cord changes are often noted on the MRI.

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A central cord-type injury is often the result in these types of injuries. Although some of these patients will slowly recover, a number will need surgical decompression of the spinal cord to promote recovery. Conservative therapy involves a rigid cervical collar and activity restriction for 2 to 3 months followed by flexion-extension films.

F.

Ankylosing spondylitis is an inflammatory arthropathy that affects the spine and sacroiliac joints. Care of these patients is extremely difficult and should be guided by a spine specialist to avoid iatrogenic injury. The ligaments and intervertebral discs become calcified and fuse to form a “bamboo spine” that often results in a flexion contracture. The rigid and weakened bone, which is prone to bleed, fractures easily. Fractures often occur in the low cervical region, and can be difficult to identify on plain radiographs. Frequently, the underlying deformity is not known, positioning is difficult and dangerous for imaging studies, and these patients can deteriorate neurologically because of malposition of the neck and their propensity to develop epidural hematomas. Excessive extension must be avoided. Prepositioning x-rays are essential to determine the baseline anatomy.

VIII. Surgical Management of Thoracolumbar Spinal Column Injuries

A.

Compression fractures typically involve the anterior column only. CT will differentiate a one-column injury from a more unstable two-column injury. The lateral film will show the loss of vertebral height (Fig. 18-9). Greater than 40% loss of height can signal an unstable fracture requiring surgical treatment. This amount of wedging associated with posterior tenderness generally signals a ligamentous injury to the posterior column. Multiple compression fractures can be unstable and should be watched closely. Higher fractures (T1-T9) require much more

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energy to fracture because of rib cage stability and are associated with more serious injury. Multiple rib fractures and sternal fractures are associated with instability. Most T10-L5 compression fractures with <40% loss of height and no posterior tenderness can be managed in a brace. Kyphoplasty and vertebroplasty, which involve injection of viscous cement into the fracture bed, are emerging as therapeutic options. Their role is still being defined in the acute setting.

Figure 18-9. T9 compression fracture as seen on lateral radiograph (A) and axial computed tomography scan(B).

• Imaging (CT, MRI) is indicated for any compression fracture associated with neurologic injury, >30% loss of height of vertebral body, and any patient with posterior tenderness or widening of the pedicles on an AP view. These patients should be evaluated by a spine surgeon.

B.

Burst fractures involve the anterior two columns and are generally considered unstable. X-ray findings are positive when the lateral view shows loss of vertebral height, widening of the spinous processes, or interruption of the posterior vertebral body line. The AP view shows widening of the pedicles, widening between the spinous processes, and loss of vertebral height. Many of these patients have neurologic injury. All of these fractures should have detailed imaging studies and the patients should receive spine service consultation. Although surgical fusion remains the standard of care, neurologically intact patients without evidence of damage to the posterior osteoligamentous complex may be managed in an extension brace for 3 months. Patients receive close radiographic follow-up with concern for progressive kyphosis. Patients with a progressive deficit require emergent operative intervention. Surgery may be deferred in those with a stable deficit for the theoretical benefit of allowing progression and resolution of cord edema and inflammation, which may reduce the risk of iatrogenic injury.

C. Flexion or distraction (seat belt or Chance) fractures

This axially oriented fracture is caused by a flexion injury around an anterior fulcrum (lap belt without shoulder harness). The fracture can split the pedicles in half, tear open the disc space, or spare bone elements and be ligamentous in nature. The excessive flexion motion places the spine in kyphosis. This injury is associated with a 30% to 45% incidence of abdominal injury and 13% risk of paralysis. Some of the pure bony injuries can be managed nonoperatively by placing the patients in an extension brace to bring the fractured bony elements into apposition, but ligamentous injuries require surgery. These injuries require detailed imaging studies.

D.

Fracture-dislocations are highly unstable and require imaging studies on all patients. Most occur at the thoracolumbar junction. The more cephalad the injury, the more likely paraplegia will result (90% above T10 and 60% below T10). The AP and lateral views will show translation of the spine as well as fractures in the facets, dislocations, or comminution fraction. These injuries require detailed radiographic studies, followed by surgical stabilization.

E.

Sacral fractures are difficult to see on x-ray film and will require CT for delineation. Fractures lateral to the sacral foramen have a 6% incidence of neurologic injury (L5 root) and fractures through the foramen have a 28% incidence. Fractures medial to the foramen through the canal have an associated neurologic injury in 57%, most involving bowel and bladder function. Displaced fractures can require surgery.

IX. Gunshot Wounds to the Spine

A.

Penetrating injuries to the spine should be treated as elsewhere in the body. The standard surgical principles of debridement and closure can be applied. The caveat is that patients with cerebrospinal fluid (CSF) leaks are at risk of meningitis and paravertebral abscess formation, unless CSF egress is controlled. Steroid therapy is contraindicated in this population due to the risk of infection.

B.

In general, large penetrating wounds require exploration and debridement. Wound cultures are taken and all potentially contaminating material (e.g., clothing fragments or shotgun wadding) is removed. Passage through the esophagus, pharynx, or colon before traversing the spine has the potential to cause spinal sepsis. Radical debridement of the spine is no longer advocated in this situation. Minimal debridement of bullet tract and 1 to 2 weeks of broad-spectrum antibiotics is

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sufficient to decrease the chance of spinal infection to about 10% of cases when the bullet traverses the colon, esophagus, or pharynx.

C.

Removing bullet fragments may necessarily be delayed if an abnormal lead level develops. Removal of a bullet from the spinal canal is recommended with a worsening neurologic picture or evidence of neurologic compression on radiographic studies. These procedures can be facilitated if performed in a delayed fashion to allow easier dural repair. CSF diversion (e.g., lumbar, cervical, or ventricular drainage) may be required for persistent leakage. Neurologic deterioration mandates a more urgent approach to debridement.

D.

Few civilian spinal injuries caused by the bullet striking the spinal column are unstable enough to require surgical stabilization. The three-column theory can be used to dictate treatment. If two of three columns are involved, a rigid orthosis is necessary. Flexion or extension films may be necessary to determine stability.

Axioms

• The most important factors when treating injuries to the spine are attention to the mechanism of injury, understanding the level of neurologic function at the time of injury compared to later presentation, maintaining a continual awareness of other injuries to the spine, confounding injuries, and patient variables.
• The most commonly missed fractures occur at the C1 to C2 and C7 levels.
• The general assumption is that all patients have an unstable spine until proven otherwise.
• Patients with continued complaints of spine-related pain must be thoroughly evaluated and this evaluation must be repeated if the symptoms persist.
• Patients with ankylosing spondylitis have a significant risk of missed or iatrogenic injury and should be managed closely by a spine specialist.
• Should any doubt about the injury persist, evaluation by a spine surgeon is necessary.

Prehospital Care spinal cord injuries

Prehospital Care

A.

Treatment in the field of patients with spinal column and spinal cord injuries follows the basic prehospital protocols (Chapter 6). Treatment is directed to establishment of an adequate airway, ventilation of the lungs, and maintenance of circulatory support to prevent secondary neurologic injuries.

B.

Intubation is best accomplished by using manual inline immobilization, avoiding flexion of the neck. Fiberoptic intubation may also reduce spine manipulation. The patient's neurologic status as well as pulmonary function should be assessed and recorded, especially patients with high quadriplegia.

Figure 18-1. Drawing showing the three columns of support in the spine.

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C.

Hypovolemic and neurogenic shock can occur in the setting of SCI. The cause of hypotension must be determined and treated immediately. Hypotension should be regarded as a sign of abdominal bleeding, aortic or cardiac injury, external blood loss, or occult injury before considering neurogenic shock. Regardless of the cause, shock should be aggressively treated to prevent further ischemic injury to the spinal cord. Treatment consists of fluid administration and vasopressors to maintain the mean systemic blood pressure at approximately 90 mmHg. The patient is reevaluated continuously in the emergency department. Resuscitative measures are continued and modified as needed.

D.

An estimated 3% to 25% of spinal cord injuries occur iatrogenically after the initial trauma, either in transport or during early resuscitation. After medical stabilization on the scene, the cervical spine should be immobilized in a rigid collar in any patient who is unconscious or suspected of having a cervical injury. A scoop stretcher or similar backboard with supportive blocks and straps should be used rather than logrolling to prevent uncontrolled motion. The patient should remain on a backboard until evaluated in the emergency department. Transport to a definitive treatment center should be the goal, as delays can incur worse outcomes, longer hospitalization, and higher costs.

IV. Neurologic Evaluation

A.

A standard neurologic examination is performed on each patient. This includes evaluation of mental status, cranial nerves, motor testing, sensory testing, and reflex assessment. Further specialized testing can be deferred.

B.

The Glasgow Coma Scale (GCS) score is determined and recorded. The mental status is established as to person, place, and dates, surrounding the events. Cranial nerve evaluation is done with special attention directed to pupillary size and symmetry. Acute changes in the pupillary diameter can indicate a brain herniation syndrome and may require emergent surgery, hyperventilation, or diuresis.

C.

Motor evaluation is performed for the GCS and SCI evaluation. The patient is asked to move all extremities individually and strength is assessed according to the American Spinal Injury Association/International Medical Society of Paraplegia (ASIA/IMSOP) protocol. Normal strength is graded 5/5, with mild weakness graded as 4/5. The ability to fully overcome gravity through a full range of motion is graded 3/5. Movement throughout a range of motion but unable to overcome gravity is graded 2/5. Flicker motion of muscles is 1/5 and no movement is 0/5. Patients with C5 levels of spinal cord function will be able to flex only their arms and should not be confused with pathological flexor posturing.

D.

Sensory testing is performed with regard to light touch and pain perception (Fig. 18-2). Useful examination tools include a cotton swab broken in half or safety pins. Pay close attention to the level of sensation and asymmetry.

E.

Reflex testing is performed at the biceps (C5), triceps (C7), brachioradialis, knee (L4), and ankle areas (S1). Special reflex testing including jaw jerk, deltoid (C5), pectoral, superficial abdominal (T9-T12), bulbo- or cliterocavernositis (S3-S4), anal wink (S5), and Babinski. The extremity reflexes are graded on a scale of 0 to 4, where 0 = absent reflex activity, 1 = decreased reflex activity, 2 = normal reflex activity, 3 = increased reflex activity, and 4 = grossly exaggerated reflex activity with sustained clonus. An exaggerated jaw jerk indicates injury at or above the pons. Deltoid and pectoral reflexes are usually associated with significant hyperreflexia. Bulbo- or cliterocavernosis reflexes may be retained in complete injury, but lost during spinal shock. Their reappearance may indicate that a period of spinal shock has ended. Babinski responses are recorded as present or absent. The presence of UMN findings (hyperreflexia, loss of superficial abdominal reflexes, Babinski responses) indicates spinal cord or conus medullaris injury. Decreased reflexes imply LMN (cauda equina and nerve root) injury. Weakness, sensory loss, and bladder, bowel, and sexual dysfunction can be seen with either UMN or LMN injuries. Of note, acute UMN injuries often present with reflex stunning or are-flexia, which may last for 24 to 48 hours.

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Figure 18-2. Anterior (A) and posterior (B) cervical, thoracic, lumbar, and sacral dermatomes. (From McDonald JV, Welch WC. Patient history and neurologic examination. In: Welch WC, Jacobs GB, Jackson RP, eds. Operative Spinal Surgery. Stamford, Conn: Appleton & Lange; 1999;3:15, with permission.)

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F.

The most sensitive predictor of prognosis is the severity of neurologic injury as characterized by level and completeness of deficit. The neurologic sensory levels are determined and recorded based on the lowest segment with normal sensory and motor function bilaterally. Complete injury is seen in the patient without sensory or motor function below the level of neurologic injury, including loss of perianal sensation and sphincteric function. The patient with incomplete injury has partial preservation of sensory or motor function below the level of neurologic injury, with preservation of perianal sensation and motor function. This is often referred to as sacral sparing, and does not include an intact bulbo/clitoro cavernosus reflex which can be present in complete injuries.

G.

In the acute setting, the use of specific terms denoting neurologic level is preferable to more general terms (e.g., paraparesis, quadriplegia). The ASIA impairment scale, consisting of a five-point grading scale, is as follows:

• Complete loss of sensory and motor function (including the sacral area) below the neurologic level.
• Incomplete injury, whereby sensory function is preserved below the level of neurologic injury including the sacral area.
• Incomplete injury with motor function preserved below the neurologic level and most preserved groups exhibiting strength of ≤3.
• Incomplete injury with motor function preserved below the neurologic level and most preserved groups exhibiting ≥3 strength.
• Normal sensory and motor examination. Even patients with ASIA 1 scores can improve neurologically, although few of these patients will achieve functional motor recovery.

H.

Another useful descriptor of spinal cord injuries involves pathologic criteria. These syndromes correlate to anatomic areas of injury.

• Posterior cord injury with loss of position sense (posterior columns) is rarely traumatic. This injury is usually related to vitamin deficiencies and infections (e.g., syphilis). The patients develop a loss of position and vibratory sense.
• Central cord injury is common in patients who experience excessive motion in the sagittal plane (e.g., hyperflexion and hyperextension), particularly those with preexisting cervical stenosis. These injuries represent a centripetal force applied to the spinal cord with resultant central necrosis secondary to vascular compromise. The hallmark features are hand weakness more than leg weakness, bladder dysfunction, and variable degrees of sensory loss below the level of the lesion.
• Anterior cord injury suggests anterior spinal artery occlusion and results in loss of all motor and sensory function other than proprioception.
• Brown-Sequard (cord hemisection) syndrome is identified by loss of ipsilateral motor function, ipsilateral position sense, and contralateral loss of pain and temperature sensation two to three segments below the level of injury.

I.

Conus medullaris and cauda equina syndromes occur at the thoracolumbar levels and result in varying degrees of weakness, sensory loss, bladder, bowel, and sexual dysfunction. Conus injuries affect UMNs, which may precipitate hyper-reflexia. Conus injuries may also cause reflex stunning with the loss of the bulbo-cavernosus reflex. The cauda equina syndrome typically results from a compres-sive lesion below the level of the spinal cord with resultant bowel/bladder dysfunction, saddle paresthesias, and lower extremity weakness. This represents one of the few operative emergencies and should be alleviated as soon as safely possible to attain maximal recovery and prevent further deterioration.

V. Radiographic Evaluation

The diagnosis of spinal cord or spinal column injury is of paramount importance in the acute setting. The diagnosis is reached by obtaining a history of the events, performing a neurologic evaluation of the patient, and obtaining the appropriate radiographic evaluation. The initial studies should cover the area of suspected injury. Patients with persistent complaints of pain along the spine should be assumed to have a spinal column injury until proven otherwise. Patients with a normal x-ray study and severe neck pain should remain in a rigid cervical collar. MRI should be obtained in this setting. Follow-up flexion/extension

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films can be completed about 3 days after injury to rule out instability that was masked by muscle spasm. Keep in mind that 10% to 15% of patients with one spine fracture will have another fracture elsewhere in the spine. The “skeletal level” is used to denote the area of greatest vertebral injury and can be different from the neurologic level(s).

A. Cervical spine

• The cervical spine can be clinically cleared without radiography in patients who present with a GCS of 15, with no evidence of drug or alcohol use, normal neurologic exam, without midline cervical pain, and without distracting or significant injuries. The Canadian C-spine rules provide a well-validated algorithm to avoid unnecessary imaging with a sensitivity of 100%. For the majority of trauma patients who do not meet these guidelines, evaluation starts with plain films. The sensitivity and specificity of plain radiography to detect a fracture remain below 90%. This compares to a reported sensitivity and specificity of 96.0% and 96.5%, respectively, for CT. With a 14.5% probability of paralysis for missed injuries, CT has emerged as the diagnostic modality of choice. However, the negative predictive value of CT combined with plain films exceeds 99%, prompting our institution to always obtain at least a lateral C-spine. Fractures may be missed with CT if they extend horizontally in the axial plane, parallel to the tomographic imaging slice. While cost remains a point of contention, in moderate- to high-risk patients in urban trauma centers, CT can be cost-effective. Of note, the most commonly missed cervical fractures are at the C1 to C2 and C7 to T1 levels, usually the result of inadequate imaging.
• The basic lateral radiographic studies must include the skull base and T1 vertebral body for adequate interpretation. A “swimmer's view” may be required to fully assess C7 to T1. Oblique views may also help assess C7 to T1, although a CT is usually obtained after two attempted failures to obtain adequate plain films. The films are reviewed with careful attention to three lines:
  • Posterior vertebral body line
  • Anterior vertebral body line
  • Spinolaminar line (Fig. 18-3)
• These lines should be uninterrupted and smooth. The appearance of a straight spine (loss of the normal cervical lordosis) indicates extensor muscular spasm and can suggest spinal injury. A rigid cervical collar can also cause loss of lordosis. The vertebral canal is defined as the distance from the spinolaminar line to the posterior vertebral body line. This space available for the cord should be >13 mm at every level. A narrower canal may represent injury or congenital cervical stenosis.
• Soft tissues are then examined. The trachea contains air and provides a line of contrast against the vertebral bodies. Prevertebral swelling indicates a hematoma consistent with spinal column injury. The hematoma can also compromise the patient's airway, leading to respiratory collapse. An easy rule to remember is that the soft-tissue space should be no greater than 6 mm in front of the C2 vertebral body and no greater than 22 mm anterior to C6. Another important distance is the atlantodens interval. This is the space between the anterior aspect of the odontoid (dens) and the ring of C1. This space should not exceed 3.5 mm in the adult and 5 mm in the child. Distances greater than those indicate disruption of the transverse ligament, with resultant instability.
• Vertebral height is examined next, including vertebral body morphology. The vertebral bodies should be similar in appearance, without evidence of compression or fracture. The distance between the posterior spinous processes, or interspinous distance, should be similar at each level.
• Other radiographs obtained of the cervical spine include the open mouth view of C1 to C2. This study shows the base of the odontoid and helps determine whether a type I, II, or III odontoid fracture (discussed below) is present. The lateral masses of C1 are examined with regard to their relationship to C2.

  Figure 18-3. Normal cervical spine lateral radiograph demonstrating spinolaminar line (arrows).

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• Little or no overhang of the lateral masses should be seen. A combined, bilateral overhang ≥6.9 mm indicates a fracture of the ring of C1, with probable disruption of the transverse ligament. The odontoid bone should be symmetrically located between the lateral masses of C2.
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• The anteroposterior (AP) view of the spine is examined for the distance between spinous processes, alignment, and rotation. Facet anatomy is more closely observed with oblique views of the cervical spine. Areas suspected of having fracture can be further assessed with fine-cut CT. MRI is indicated in patients with neurologic deficits or significant fractures that will require reduction. The MRI yields information as to ligamentous integrity, subtle compression fractures, traumatic disc rupture, and SCI. Signal change on long TR images help differentiate acute injury from those that are chronic. Patients with neurologic deficits should be evaluated in consultation with the spine surgery service.
• If a conscious patient has no neck pain to palpation and can voluntarily flex, extend, and rotate without pain, and initial x-rays are normal, the collar may be removed. Should a patient have neck pain and yet have normal preliminary x-rays, further studies should be undertaken. At a minimum, flexion and extension films should be performed to rule out ligamentous instability. These must visualize C7 to T1. A normal three-view films and flex-extension series has a negative predictive values greater than 99%. Further radiographs, including magnetic resonance imaging (MRI) and even bone scan, can be appropriate to rule out possible bone or ligamentous injury. The rigid collar should remain in place until the neck is cleared clinically and radiographically.

B. Thoracolumbar spine

• The thoracolumbar spine is commonly injured at the T12 to L1 levels. This occurs because of the large lever arm created by the inflexible thoracic spine as it joins the lumbar spine. This area of the spine is well examined with lateral and AP views. Three lines are observed along the anterior and posterior aspects of the vertebral bodies, and along the posterior aspect of the spinous processes. The distance between these processes should also remain equal.
• On the AP view, the distance between pedicles is determined as is the distance between the posterior spinous processes. The transverse processes and ribs are evaluated for fractures and the soft tissues are examined for swelling.
• More specialized imaging studies are obtained as necessary. CT is useful for a closer examination of bone anatomy. These studies can be ordered with 1- to 3-mm cuts, and sagittal and coronal reconstruction to better define bony anatomy. MRI provides excellent visualization of the spinal cord and nerve roots and helps define spinal cord and ligamentous injury.
• AP and lateral films are indicated in those patients with symptoms referable to the thoracic area or those who have a mechanism that is consistent with such an injury. This would include patients involved in motorcycle accidents, falls from height, ejection from vehicle, or pedestrian-automobile collisions. Flexion and extension films are not as helpful in this area as compared with the cervical spine. Thoracic spine CT is indicated for those patients with fractures noted on x-ray film or when the anatomy is not well seen on plain films. MRI is indicated for all patients with neurologic findings.

C. Lumbar spine

• The lumbar spine is subjected to injurious forces in falls, motor vehicle crashes, and by other means. Because the spinal cord ends at the L1 to L2 level, true SCI from lumbar fractures is infrequent. Injuries to the conus medullaris and cauda equina can occur if the spinal canal is compromised. Commonly, no neurologic injury is noted with lumbar spine fractures.
• The lumbar spine is evaluated similar to the thoracolumbar spine. AP and lateral spine films are the initial studies.
• CT can be useful to determine the amount of canal compromise in cases of burst fracture. MRI and myelography are also helpful in cases of traumatic nerve root injury, canal compression, and conus medullaris and cauda equina syndromes.

VI. Medical Management of SCI

Once the patient has arrived in the trauma resuscitation area, more sophisticated medical management can begin. The goal is to prevent secondary cord injury, which can be exacerbated by hypotension, shock, hypoxia, hypercoaguability, and hyperthermia. Management protocols include

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definitive treatment of other injuries; maintenance of adequate blood pressure; detailed radiographic studies; high-dose steroids, if appropriate; determination of the need for surgical intervention; and postoperative rehabilitation.

A. Methylprednisolone

A number of studies have suggested that neurologic improvement can occur following the administration of high-dose steroids after blunt injury to the spinal cord. Penetrating trauma to the spine, such as gunshot wounds, are not appropriate candidates, considering the increased risk of infection. The second National Acute Spinal Cord Injury Study (NASCIS 2) showed that methylprednisolone given in a dose of 30 mg/kg intravenously (IV) over 45 minutes within 8 hours after injury in those with incomplete or suspected incomplete SCI improved neurologic outcome. The initial dose is followed by 5.4 mg/kg/h IV given over the next 23 hours by continuous drip. The NASCIS 3 study reported that if patients begin treatment between 3 and 8 hours postinjury, the steroid infusion must be extended to 48 hours to attain the same benefit as 24 hours of steroids given within 3 hours of injury. Significant, functional benefit remains inconclusive and there is no defined standard of care. Currently, the Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries (AANS) state that administration of steroids “is recommended as an option in treatment of patients with acute spinal cord injuries that should be undertaken only with the knowledge that the evidence suggesting harmful side effects is more consistent than any suggestion of clinical benefit.” In practice, the protocol is often initiated at referring hospitals prior to transfer. We routinely complete the regimen in these circumstances.

B.

Hemodynamic instability is common in acute SCI. Approximately 70% of patients with high cervical SCI will have severe bradycardia (<45 beats per minute [bpm]) and hypotension with an associated 16% incidence of cardiac arrest. Animal models have shown hypotension can exacerbate spinal cord ischemia and worsen neurologic outcome. Extensive class III data supports blood pressure augmentation to maintain mean arterial pressure (MAP) at 85 to 90 mmHg for 5 to 7 days postinjury. This therapy can be sustained with minimal morbidity and has shown improved outcomes compared to historical controls. Hypotension and hypoxia should be avoided at all costs.

C.

Other medical issues to be considered in patients with SCI include prevention and treatment of pulmonary complications. Aggressive pulmonary toilet, specialized rotating beds, and antibiotics are often appropriate. Early tracheostomy can reduce length of stay and facilitate care. After evaluating 178 patients with ASIA A SCI, 70% required a tracheostomy; 100% for injuries at or above C3 and none at or below C8. Urinary tract infections are common in paralyzed patients because of repeated catheterization. Decubitus ulcers can occur rapidly in insensate patients. Aggressive nursing care is the mainstay of treatment. Stress gastric and duodenal ulcers are common and prophylaxis is recommended. Joint con-tractures and heterotopic ossification are common in paralyzed patients. These complications can be reduced by physical therapy. SCI patients are more sensitive to acetylcholine and the use of succinylcholine can precipitate a hyperkalemic crisis. Autonomic dysreflexia occurs in up to 90% of patients with lesions above T6. Distension of hollow viscera or cutaneous stimulation can produce rapid fluctuations in blood pressure, vasoconstriction, bladder spasm, flushing, sweating, encephalopathy, seizures, congestive heart failure, and arrhythmias. Treatment involves removal of the stimulus and aggressive blood pressure control.

D.

The risk of deep venous thrombosis (DVT) and pulmonary embolus (PE) are 39% to 100% and 4% to 10%, respectively. Unfractionated or low-molecular-weight heparin and serial compression devices should be instituted as soon as medically feasible. These interventions provide a 50% reduction in incidence of thromboembolism.

E.

Patients with suspected vertebral artery injury should have a CT, MR, or catheter-based angiogram. The lower sensitivity of a computed tomography angiography (CTA) is balanced by the ease with which it is obtained, particularly for unstable patients or those receiving CT imaging of other regions.

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Indications for angiogram include a complete cervical spine injury, fracture of the foramen transversarium, facet dislocation, subluxation, or suspicious neurologic exam. Symptomatic injuries presenting with a stroke may be antico-agulated for 3 to 6 months. Asymptomatic patients should be observed and followed closely as delayed ischemia is common. Antiplatelet agents remain a viable option that will require further study, particularly for asymptomatic patients.

F.

Obtunded patients represent a particular dilemma. Prolonged cervical immobilization has been associated with decubitis ulcers, elevated ICP, pain, and pulmonary complications. Patients who have suffered neurologic injury rendering them comatose or who have other conditions that prevent them from fully cooperating with the examining physician should have complete spine radiographic evaluation. Approximately 1% of patients who are obtunded will have ligamentous instability that is missed when x-ray studies are normal. Classically, passive flexion-extension under fluoroscopy with negative plain films was utilized to rule out instability. However, visualization is inadequate in up to 30% of patients. Combined with the rare but serious potential for permanent morbidity, MRI has emerged as the study of choice to clear the cervical spine in this population. Protocols designed with limited, specialized imaging sequences can reduce time in the scanner and ultimately cost when applied routinely. Sensitivity may be increased by imaging within 48 hours to maximize visualization of edematous tissue. Without access to MRI, a collar can be left in place for 30 days, allowing time for occult ligamentous injury to heal.

Injuries to the Spinal cord and spinal Column

I. Introduction

Each year, approximately 10,000 new spinal cord injuries result in paralysis, with an estimated societal cost of $10 billion. The average age of the injured is 32 years with a 4:1 male-to-female ratio. Motor vehicle accidents account for 50% of the spinal cord injuries, sports 14%, falls 21%, and violence 15%. Of patients with spinal cord injuries, 44% also suffer from other significant trauma, with 14% having head and facial trauma. Half of all spinal cord injuries involve the cervical spine, most occurring between C4 and C7, with a 3-month mortality of 20%. Half of spinal cord injuries involve complete quadriplegia.

II. Anatomy and Biomechanical Definitions

A.

The spinal cord is a continuation of the brainstem (medulla). This area is the cer-vicomedullary junction, which is located at the foramen magnum of the skull. The spinal cord continues through the vertebral canal of the cervical, thoracic, and upper lumbar vertebra, generally ending at the L1 to L2 space. The spinal cord contains the upper motor neurons (UMNs) that synapse with lower motor neurons (LMNs) to form the nerve roots and cauda equina. The nerve roots in the cervical and lumbar regions fuse as the cervical and lumbar plexuses before separating again as specific nerves. Generally speaking, UMN lesions carry a worse prognosis than LMN lesions, as nerve roots have better capacity for repair than does the spinal cord.

B.

The spinal column is composed of 7 cervical, 12 thoracic, 5 lumbar, and 5 fused sacral vertebrae. With the exception of the sacral vertebra, the vertebral bodies articulate with each other across the intervertebral disc and facet joints, forming a functional spinal unit. The facet joints, associated ligamentous structures, and other bone articulations (e.g., the rib cage) determine the motion across two vertebral bodies. The motions are considered in the sagittal plane (flexion and extension), coronal plane (lateral flexion), and in the transverse plane (rotation). In the cervical spine, about 50% of flexion and extension occurs between the occiput and C1, whereas 50% of rotation occurs between C1 and C2. The remainder of cervical movement takes place in the subaxial (below C2) region. The thoracic spine has little motion because of the facet joint orientation and added stabilization of the rib cage. The facet joints of the lumbar spine have a more sagittal orientation and allow moderate motion in the sagittal plane while resisting rotation. The transition from the stiff thoracic spine to a mobile lumbar area accounts for the high number of injuries at the thoracolumbar junction.

C.

Injuries to the spinal column occur as a result of excessive forces applied to the spine. These forces can cause axial loading, hyperflexion, hyperextension, distraction, rotation, or a combination of forces. Injury to the spinal column can cause spinal instability, which can be defined on radiographic or clinical grounds. In the acute setting, radiographic features are most commonly used to determine spinal stability. This is reviewed later in the chapter.

D.

The conceptualization of the spine as a series of support columns increases our bio-mechanical understanding of stability. Three columns of the spine have been described for the lower thoracic and lumbar spine. The anterior column (anterior longitudinal ligament and the anterior two thirds of the vertebral body and disc),

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the middle column (posterior third of the vertebral body and disc, the posterior longitudinal ligament), and the posterior column (the facet joints, capsule, ligamentum flavum, and posterior ligaments) describe the main columns of overall biomechanical support (Fig. 18-1). The three-column theory may not be completely applicable to the cervical spine, but it is still generally used. Injuries or deficits of two of three columns denotes biomechanical instability.

E.

Spinal cord injuries can be separate and distinct from spinal column injuries. The diagnosis of a spinal cord injury (SCI) is made on clinical grounds and supplemented with diagnostic tests such as magnetic resonance imaging (MRI), myelo-graphy, or electrodiagnostic studies. The level of SCI frequently correlates with the level of spinal column injury. However, SCI can occur without spinal column injury.

F.

Spinal column injuries are bone or ligamentous disruptions that result in bone fractures or ligamentous instability. The loss of these stabilizing and supporting elements can result in compression and injury of neural elements. The diagnosis of spinal column injury is based on clinical and radiographic criteria, such as pain and ecchymosis at the level of fracture and plain film evidence of fracture. Spinal column injuries can occur without spinal cord injury.

POSTCONCUSSION SYNDROME

A.

Postconcussion syndrome can result from relatively minor head injuries.

B.

Most commonly involves headaches, tinnitus, vertigo, gait unsteadiness, emotional lability, sleep disturbances, intermittent blurring of vision, and irritability.

C.

Symptoms can continue for weeks, months, or several years, but are rarely permanent.

D.

Of patients who suffer postconcussion syndrome, 90% have spontaneous resolution of their symptoms within 2 weeks of injury. Beta-blocking agents, tricyclic antidepressants, or nonsteroidal anti-inflammatory agents may be beneficial, as well as psychotherapy and physical therapy.

E.

For those with persistent symptoms referral to a brain rehabilitation specialist is necessary.

Axioms

• Loss of consciousness is an important indicator of brain injury.
• Determine the GCS score as early as possible.
• A principal therapeutic goal is to enhance cerebral perfusion and avoid further ischemic injury.
• Early diagnosis and evacuation of mass lesions are critical.
• CT scan is the diagnostic test of choice for patients with all brain injuries.

SKULL FRACTURES

A.

Linear skull fractures are most common and typically occur over the lateral convexities of the skull. The squamous portion of the temporal bone in this region is thin and closely associated with the middle meningeal artery. Fractures in this area can tear the artery, which is the most common cause for epidural hematoma.

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For most skull fractures, it is not the fracture but rather the underlying blood clot or brain contusion that raises concern. Because these associated lesions are best detected with CT and are not recognized with plain skull x-rays, a CT of the head is the diagnostic study of choice for patients suspected of having a skull fracture.

B. Depressed skull fractures

The surgical elevation and repair of these fractures will not lead to a change in associated neurologic deficit or a decrease the risk for subsequent seizures. These fractures may be open (associated with an overlying scalp laceration) or closed. Indications for surgical repair of depressed skull fractures are evidence of CSF leak, cosmetic deformity, or contaminated bone or scalp fragments pushed into the brain. In addition, when a dural tear is suspected— usually indicated by the bone being depressed beyond the inner table—then repair should be considered. Other treatment includes:

• Broad-spectrum antibiotics for 7 to 14 days if the wounds are contaminated or the fracture involves a facial sinus
• Prophylactic anticonvulsant therapy for 7 days

C.

Basilar skull fractures which occur most commonly through the floor of the anterior cranial fossa, can disrupt the ethmoid bones and lead to CSF leak through the nose (rhinorrhea). Fractures also can occur through the petrous bones posteriorly, leading to CSF drainage through the ear (otorrhea). Cranial nerve injuries are commonly associated with posterior basilar skull fractures, and findings should be sought on clinical examination.

• The primary concern with basilar skull fractures is associated CSF leak and risk of meningitis.
• Prophylactic antibiotic treatment is not recommended. Several investigations have found that morbidity is increased with prophylactic antibiotics because of selection of more virulent organisms.
• Attempts to stop the leak should begin with elevation of the head of the bed to 60 degrees. If the leak does not stop within 6 to 8 hours, a lumbar CSF drainage catheter should be placed (provided there are no contraindications on CT such as edema or a mass lesion), and 50 to 100 mL of CSF should be drained every 8 hours. If this fails to stop the leak within 72 hours, the patient should be taken to surgery for repair of the dural laceration. When a patient deteriorates while undergoing lumbar CSF drainage it may be associated with overdrainage or meningitis. The lumbar drain should be closed if this happens.

PENETRATING BRAIN INJURIES

A.

Penetrating injuries can be subcategorized into gunshot wounds and lower velocity injuries; the prognosis between the two is very different.

• Gunshot wounds to the brain carry a high mortality rate. As the bullet traverses the brain tissue, it causes a cylinder of tissue destruction extending perpendicular from the bullet tract to a distance of as much as 10 times the diameter of the bullet.
• General management of gunshot wounds to the brain follows the same principles of cerebral resuscitation as other brain injuries. The incidence of elevated ICP is high.
• Superficial debridement of the entrance and exit wounds is generally recommended, although it is usually not necessary to retrieve all deep-seated bullet and bone fragments.
• Broad-spectrum intravenous antibiotics and prophylactic anticonvulsant therapy are recommended.
• Prognosis depends largely on the trajectory of the bullet through the brain. If the bullet traverses deep brain structures (e.g., the basal ganglia or brainstem), traverses the posterior fossa, or has a transcranial trajectory, the mortality rate is high. If the bullet avoids these structures, the outcome can be more optimistic.
• Patients with an initial GCS score of 3 to 4 will have a high mortality rate (>80%). Conversely, 80% of patients who are able to follow commands on admission to the hospital (GCS >8) will have mild or no disability.

B.

Lower velocity missile wounds. The most important factor determining outcome from lower velocity missile wounds (e.g., stab or arrow wounds) to the head is the location of brain injury. If the missile damages the motor cortex, for example, contralateral motor weakness should be confined to the area of cortex that was damaged.

• The missile may be tamponading a major intracranial arterial injury, so it is best to remove protruding knives or other objects only in the operating room and only when the surgeon is prepared to deal with the consequences of major arterial bleeding.
• A 7- to 14-day course of broad-spectrum antibiotics and prophylactic anti-convulsants (7 days) is indicated.

C.

Following a penetrating head injury—including high- or low-velocity missile or nonmissile injury (e.g., stab wound)—it is important to perform an angiogram to exclude a traumatic aneurysm.