Spine



Spine


Jay S. Reidler

Eric Wei

A. Jay Khanna

Francis H. Shen

David J. Kirby

Varun Puvanesarajah

Matthew Hoyer

Michael McColl



ANATOMY


Vertebral Column



  • Overview



    • 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), and 4 coccygeal (fused)


    • Supports and protects spinal cord and nerve roots


    • Denis three-column theory (Figure 9.1)



      • Anterior column



        • Anterior two-thirds of vertebral body and annulus


        • Anterior longitudinal ligament (ALL)


        • Weight bearing in the erect position


      • Middle column



        • Posterior one-third of vertebral body and annulus


        • Posterior longitudinal ligament (PLL)


      • Posterior column



        • Pedicles, facets, lamina, and spinous processes


        • Posterior ligamentous complex (PLC)



          • Supraspinous ligament


          • Interspinous ligament


          • Ligamentum flavum


          • Facet capsules


        • Paravertebral musculature attachments


    • Typically, vertebral size increases caudally (more weight supported)


    • Normal curvature



      • Cervical lordosis


      • Thoracic kyphosis


      • Lumbar lordosis


      • Sacral kyphosis






        Figure 9.1 Denis three-column theory. From Greenleaf R, Richman JD, Altman DT. General principles of vertebral bony, ligamentous, and penetrating injuries. In: Brinker MR, ed. Review of Orthopaedic Trauma. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:406-417.



  • Cervical



    • Atlanto-occipital joint



      • Occipital condyles of the skull articulate with superior facets of the atlas.


      • Tectorial membrane—extension of PLL


      • 50% of head flexion/extension (˜50°)


    • C1 (atlas)



      • No vertebral body


      • No spinous process


      • Vertebral arteries travel through transverse foramen and then enter the foramen magnum (to avoid injury, C1 dissection should not be >1.5 cm lateral from the midline in an adult; Figure 9.2).


    • C2 (axis)



      • Odontoid process is the attachment site of the alar and cruciate ligaments.



        • Transverse bands of cruciate ligament are the most critical for C1-C2 stability.


      • Bifid spinous process


      • 50% of cervical rotation occurs at atlanto-axial joints (˜50°).


    • C3-C7 vertebrae



      • Bifid spinous process except for C7


      • Vertebral arteries do not travel in C7 transverse foramen.


      • Subaxial spine contributes to cervical motion: lateral flexion (˜60°), flexion/extension (˜50°), and rotation (50°).


  • Thoracic



    • Costal facets articulate with the ribs, providing rigidity.


    • Normal thoracic kyphosis is 20° to 50°.


    • Largest transverse processes






      Figure 9.2 Anatomic relationship between C1 and the vertebral artery. From Schoenfeld AJ, Le HV, Bono CM. Cervical spine fractures and dislocations. In: Tornetta P III, Ricci WM, Ostrum RF, et al, eds. Rockwood and Green’s Fractures in Adults. Vol 2. 9th ed. Philadelphia, PA: Wolters Kluwer; 2020:1817-1899.



    • T5—narrowest pedicle


    • Range of motion: flexion/extension (75°), lateral flexion (75°), and rotation (70°)


  • Lumbar



    • Normal lumbar lordosis is ˜60° (range, 20°-80°).


    • Cauda equina begins at L1-L2.


    • Range of motion: flexion/extension (85°), lateral flexion (30°), and rotation (10°)


  • Sacrum



    • Five fused vertebrae


    • Four pairs of pelvic sacral foramina ventrally and dorsally


    • Sacral canal opens into sacral hiatus.


  • Coccyx



    • Four fused vertebrae


    • “Tailbone”


    • Muscular attachments



      • Gluteus maximus muscle


      • External anal sphincter


      • Levator ani muscle (including coccygeus)


  • Facet joints



    • Synovial joints that facilitate and limit spinal motion: flexion, extension, and rotation


    • Orientation varies with spinal level.


    • Thin layer of hyaline cartilage between articulating surfaces


Ligaments (Figure 9.3)



  • ALL



    • Prevents hyperextension


    • Supports annulus fibrosus


    • Thick at center of vertebral body and thin at edges


  • PLL



    • Prevents hyperflexion


    • Hourglass shape with wider and thinner sections over disks






      Figure 9.3 Ligaments in the upper cervical spine. From Meinhardt PA, Milam RA, Darden BV II. Cervical spine: plain radiography. In: Benzel EC, ed. The Cervical Spine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:278-290.



  • Ligamenta flava



    • Connect laminae of adjacent vertebrae from axis to sacrum


    • Hypertrophy may exacerbate nerve root compression.


  • Denticulate ligaments



    • Interconnect pia mater with dura mater


    • Suspend and provide stability to the spinal cord


    • Extend down to T12


  • Supraspinous ligament



    • Continuation of ligamentum nuchae in cervical spine—C7 to sacrum


    • Limits hyperflexion of the spine


  • Interspinous ligaments



    • Between adjacent spinous processes


    • Limits hyperflexion of the spine


  • Intertransverse ligaments



    • Between transverse processes


    • Limits lateral flexion of the spine


Intervertebral Disks



  • Overview



    • Twenty-three fibrocartilaginous disks starting at C2-C3 and ending at L5-S1


    • Constitutes 20% to 33% of vertebral column height—aging causes disk dehydration and height decrease


    • Cross-sectional areas of disks increase craniocaudally. L4-L5 disk space is largest.


  • Vasculature



    • At birth, blood vessels that are present at endplates perforate intervertebral disk, extending into the annulus fibrosus.


    • Normal adult intervertebral disk is avascular, with capillaries terminating at endplates; receives nutrients via passive diffusion.


  • Structure



    • Annulus fibrosus—peripheral



      • Outer layer—type I collagen fibers, obliquely oriented


      • Inner layer—fibrocartilage


      • High tensile strength


      • Superficial fibers of annulus fibrosus innervated by sinuvertebral nerves from dorsal root ganglia


    • Nucleus pulposus—central



      • Negatively charged proteoglycans


      • Type II collagen


      • Hydrophilic matrix


      • Approximately 88% water


      • No innervation


      • High compressive strength


Musculature



  • Extrinsic muscular attachments—trapezius, rhomboids, serratus posterior, and latissimus dorsi


  • Intrinsic muscles



    • Superficial



      • Splenius capitis and cervicis muscles


      • Lateral flexion of neck


    • Intermediate



      • Three erector spinae muscles—spinalis, longissimus, and iliocostalis muscles


      • Trunk extension and lateral flexion



    • Deep



      • Semispinalis muscles—neck extension


      • Multifidus and rotatores muscles—stabilize and rotate vertebrae


Nervous System



  • Spinal cord (Figure 9.4)



    • Part of the central nervous system


    • Meninges cover spinal cord



      • Pia mater (innermost layer)


      • Arachnoid mater—subarachnoid space (between pia and arachnoid mater)






        Figure 9.4 Spinal cord anatomy. A, Spinal segments demonstrating cervical and lumbar enlargements. B, Layers surrounding the spinal cord include the dura mater, arachnoid mater, and pia mater. From Splittgerber R. Spinal cord and ascending, descending, and intersegmental tracts. In: Snell’s Clinical Neuroanatomy. 8th ed. Philadelphia, PA: Wolters Kluwer; 2019:131-184.




        • Filled with cerebrospinal fluid (CSF)


        • Mechanical protection


        • Immune cells


      • Dura mater (outermost layer)


    • Terminates with conus medullaris at L1-L2, then transitions into cauda equina



      • Filum terminale


      • Nerve roots


    • Spinothalamic tracts carry sensory information.



      • Lateral—pain and temperature


      • Ventral—light touch


      • Dorsal—deep touch, vibratory, and proprioception


    • Corticospinal tracts carry motor information.



      • Medial—upper extremities


      • Lateral—lower extremities


  • Nerve roots



    • Thirty-one pairs of spinal nerves, exit through neural foramina


    • Cervical roots 1 to 7 exit canal above the pedicle of the corresponding vertebrae and cervical root 8 exits below C7 pedicle.


    • All other spine roots exit canal below the pedicles of the corresponding vertebrae.


    • Common deficits by nerve root are shown in Table 9.1.


  • Sympathetic chain



    • Twenty-two ganglia—3 cervical, 11 thoracic, 4 lumbar, and 4 sacral


    • Three cervical ganglia—stellate, middle, and superior



      • Injury of middle cervical ganglion leads to Horner syndrome.


Blood Vessels



  • Arterial



    • Vertebral arteries



      • Ascend through transverse foramen of C6-C1








        Table 9.1 Common Deficits by Nerve Root



































































        Nerve Root

        Motor

        Sensory

        Reflex


        C5

        Shoulder abduction, elbow flexion (biceps)

        Lateral arm

        Biceps


        C6

        Elbow flexion (brachioradialis), wrist extension

        Thumb, radial forearm

        Brachioradialis


        C7

        Elbow extension, wrist flexion, finger extension

        Middle finger

        Triceps


        C8

        Finger flexion

        Small finger, ulnar forearm


        T1

        Finger abduction

        Medial forearm/arm


        L1


        Groin, iliac crest

        Cremasteric


        L2

        Hip flexion, hip adduction

        Anteromedial thigh


        L3

        Hip flexion, hip adduction, knee extension

        Anteromedial thigh


        L4

        Knee extension, ankle dorsiflexion

        Lateral thigh, anterior knee, medial leg

        Patellar


        L5

        Ankle dorsiflexion, foot inversion, toe dorsiflexion, hip extension/abduction

        Anterolateral leg, dorsal foot


        S1

        Foot plantar flexion, foot eversion

        Posterior leg, lateral foot

        Achilles


        S2

        Toe plantar flexion

        Plantar foot


        S3, S4

        Bowel and bladder function

        Perianal




      • Branches supply the posterior spinal arteries and the anterior spinal artery.


      • Unite to form basilar artery


    • Three vertical arteries



      • Anterior spinal artery—runs down ventral median fissure


      • Two posterior spinal arteries—run down dorsal fissures


    • Segmental arteries



      • Enter via intervertebral foramina along with nerve roots


      • Artery of Adamkiewicz



        • Largest segmental medullary artery


        • Commonly left-sided and present between T8 and L1


        • Damage may cause paralysis


  • Venous



    • Parallels arterial supply pathways


    • There are also internal and external venous plexuses.


CERVICAL SPINE TRAUMA


Presentation and Initial Evaluation



  • Assume trauma patients have a cervical spine injury until confirmed otherwise



    • Immobilize in rigid cervical collar, use spinal board for transport, and log roll for posterior examination


    • Children: Use specialized board with occipital recess and body pad to maintain spinal alignment.


  • History



    • Often involves high-energy trauma such as motor vehicle accidents, falls from heights, and high-impact sports


    • Occurs more commonly in those >65 years of age and in men


    • Assess mechanism of injury and forces involved



      • Distraction, compression, hyperflexion, hyperextension, lateral flexion, rotational, or translation forces


      • Distractive forces can cause ligamentous injuries that are not apparent on initial imaging.


    • Incidence



      • C2 is the most commonly fractured vertebra (24%), followed by C6 and C7.


      • Subaxial spine (C3-C7) accounts for 65% of cervical fractures and 75% of cervical dislocations/subluxations.


  • Physical examination



    • Examine for midline bony tenderness.


    • Complete neurologic examination, including cranial nerves, which can be involved in high cervical spine injuries


    • Hoffman sign: Flick finger nail and observe for reflexive thumb contraction, which may suggest cervical myelopathy or cord injury.


    • Romberg sign: Standing patient is asked to close eyes and stand still; swaying or imbalance suggests injury to cerebellum or dorsal column of the spinal cord that mediates proprioception.


    • In subacute setting, if there is no longer suspicion for fracture or dislocation:



      • Lhermitte sign: Maximally flex the neck and trunk. Radiating pain down the arms or spine suggests cervical spinal stenosis.


      • Spurling sign: Patient’s head is extended and rotated to the side of suspected neural impingement and axially compressed. Radiating pain suggests cervical foraminal stenosis.


  • Imaging



    • Cervical spine clearance without radiographic imaging



      • National Emergency X-Radiography Utilization Study (NEXUS) low-risk criteria



        • Patient must be awake and alert



        • Patient cannot be intoxicated


        • No neurologic deficits


        • No painful, distracting injuries


        • No posterior midline cervical spine tenderness


      • Canadian C-spine rule (CCR)



        • Absence of all high-risk factors that necessitate radiography



          • Age ≥65 years


          • Dangerous mechanism


          • Paresthesias in extremities


        • Presence of any low-risk factors that suggest range-of-motion testing would be safe



          • Simple rear-end motor vehicle collision


          • Sitting position in the emergency department


          • Ambulatory at any time


          • Delayed (not immediate) onset of neck pain


          • Absence of midline cervical spine tenderness


        • If criteria 1 and 2 are satisfied, test range of motion; if patient can rotate neck actively 45° to the left and right, cervical spine can be cleared without radiography.


      • CCR has higher sensitivity and specificity for cervical spine injury and decreases radiography rates when compared with NEXUS criteria.


    • If the cervical spine cannot be cleared clinically, radiographs (anteroposterior [AP], lateral, odontoid views, and swimmer’s view if needed to visualize cervicothoracic junction) and/or computed tomography (CT) should be obtained.



      • Inspect the following on the lateral cervical spine radiograph: anterior vertebral line, posterior vertebral line, spinolaminar line, and spinous process line (Figure 9.5).


      • Prevertebral soft tissues are normally ≤6 mm at C2 and ≤18 mm at C6.


      • Order magnetic resonance imaging (MRI) if there is concern for neurologic or major soft-tissue (eg, ligamentous) injury as MRI provides the best visualization of spinal cord injury, disk herniation, and PLC disruption.


      • Order magnetic resonance angiography or CT angiography if there is concern for vertebral artery injury.


  • Treatment principles



    • Select operative versus nonoperative treatment according to specific patient-related factors: previous functional level, medical comorbidities, associated injuries, and the patient’s personal wishes.


    • Surgical treatment usually aims to:



      • Reduce spinal cord or nerve root compression


      • Provide mechanical stability, thereby preventing pain, deformity, and further neurologic injury


Occipital Condyle Fractures



  • Often caused by axial loading of the skull on C1 lateral masses or by lateral hyperflexion injuries


  • Anderson and Montesano classification



    • Type I: compression/impaction-type fracture causing occipital condyle comminution


    • Type II: shear-type fracture extending into the skull resulting from direct blow to the skull


    • Type III: condylar-alar ligament avulsion fracture resulting from forced rotation and lateral bending


    • Type I and type II injuries are usually stable and treated with cervical orthosis if there is no fragment displacement into the foramen magnum (alar ligaments and tectorial membrane usually preserved).



    • Type III injuries are more likely to be unstable, requiring halo immobilization or occipitocervical arthrodesis.



      • Anterior pin placement when applying a halo should be superolateral to the eyebrow to avoid supraorbital nerve injury.






Figure 9.5 Lateral cervical spine lines. A, When viewing lateral cervical spine radiographs, it is important to ensure there are no disruptions in the anterior vertebral, posterior vertebral, spinolaminar, posterior spinous, and clivus-odontoid lines. B, Lateral cervical spine radiograph demonstrating intact lines. From Greenspan A, Beltran J. Spine. In: Orthopedic Imaging: A Practical Approach. 6th ed. Philadelphia, PA: Wolters Kluwer Health; 2015:442-510.







Figure 9.5 (continued)


Atlanto-Occipital Dissociation



  • Usually highly unstable and involves alar ligament and tectorial membrane disruption


  • Traynelis classification



    • Type I: anterior dislocation (occiput translated anteriorly relative to cervical spine)


    • Type II: longitudinal dislocation (occipital condyles distracted off of atlas)


    • Type III: posterior dislocation (occiput translated posteriorly relative to cervical spine)


  • Powers ratio calculated on CT



    • Powers ratio = (basion to posterior arch of C1 distance)/(anterior arch of C1 to opisthion distance) (Figure 9.6)


    • Powers ratio >1 is suggestive of anterior dislocation.


  • Basion-dens interval calculated on CT



    • Value of 9 to 12 mm also suggestive of atlanto-occipital dissociation


  • Atlanto-occipital dissociations usually require posterior occipitocervical arthrodesis for maintenance of long-term stability.


C1-C2 Subluxation (Atlanto-axial Instability)



  • Atlanto-dens interval (ADI)



    • In healthy adults—usually <3 mm for men and <2.5 mm for women


    • In children <15 years of age—usually <5 mm


  • Chronic instability can usually be seen on flexion-extension views, although such views would usually be contraindicated after an acute trauma when instability is suspected.


  • C1-C2 subluxation caused by forced flexion of the neck leads to:



    • Rupture of the transverse ligament (best seen on MRI) or


    • Avulsion fracture of C1 lateral mass via pull by the transverse ligament (fragment best seen on CT)







      Figure 9.6 Powers ratio. Basion to posterior arch of C1 distance divided by anterior arch of C1 to opisthion distance. From Patel AA, Spiker WR, Ghanayem AJ. Functional anatomy of joints, ligaments, and disks. In: Benzel EC, ed. The Cervical Spine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:43-52.


  • Treatment



    • Transverse ligament rupture—often requires C1-C2 arthrodesis because of instability and poor ligamentous healing potential


    • Avulsion fracture—often treated with halo immobilization because of potential for osseous healing of C1 lateral mass avulsion fracture


  • Atlanto-axial rotatory subluxation



    • Caused by combined rotatory and flexion or extension forces; can occur spontaneously without any clear trauma


    • Fielding classification assesses:



      • Pivot point (odontoid or facet)


      • Transverse ligament competence


      • ADI


    • In about half of cases, the odontoid serves as the pivot point, the transverse ligament remains intact, and the ADI is <3 mm. Treat with gradual cervical halter traction with patient supine.


    • Rarely necessitates C1-C2 arthrodesis


C1 (Atlas) Fractures



  • Caused by high-energy axial loads


  • Fracture patterns



    • Anterior arch fractures


    • Posterior arch fractures


    • Transverse process fractures


    • Lateral mass fractures (often comminuted)


    • Burst fractures (ie, Jefferson fractures): combined anterior and posterior arch fractures







      Figure 9.7 Jefferson fracture. From Morgan RA. Acute management of spine trauma. In: Swiontkowski MF, ed. Manual of Orthopaedics. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:232-261.


  • If isolated, C1 fractures are usually not associated with spinal cord injury because of the large space available for the cord at this level.


  • Most fractures can be treated in cervical orthosis or halo immobilization if the transverse ligament remains intact.


  • Burst fractures (ie, Jefferson fractures; Figure 9.7)



    • Usually involve lateral mass displacement away from the spinal canal


    • On odontoid radiographic view, if C1 right and left lateral mass overhang distance (compared with C2) is greater than 7 to 8 mm, then the transverse ligament is considered ruptured and the fracture is deemed unstable; this necessitates C1-C2 arthrodesis (or occipitocervical arthrodesis if inadequate C1 bony purchase).


C2 (Axis) Fractures



  • Categories



    • Odontoid process fractures (˜50% of C2 fractures)


    • Lateral mass fractures


    • Pars fractures (also known as “Hangman’s fracture”)


  • Odontoid process fractures (Figure 9.8)



    • Result from hyperextension or hyperflexion injuries


    • Classified in relation to watershed area at the base of the dens, from which the odontoid process receives its vascular supply






      Figure 9.8 Odontoid process fractures. From Morgan RA. Acute management of spine trauma. In: Swiontkowski MF, ed. Manual of Orthopaedics. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:232-261.




      • Type I: apical avulsion fracture (involves alar ligament)


      • Type IIA: base fracture at the junction of the odontoid process and C2 body—minimally displaced


      • Type IIB: base fracture—displaced with anterosuperior to posteroinferior oblique fracture line


      • Type IIC: base fracture—displaced with anteroinferior to posterosuperior oblique fracture line


      • Type III: body fracture in the C2 cancellous bone, possibly extending into lateral facets


    • If isolated injuries, type I and III fractures are usually stable and have good healing potential with cervical collar (Type I) or halo immobilization (Type III).


    • Type II fractures have a high nonunion rate and can often benefit from surgical fixation. Nonunion risk factors:



      • Increased patient age


      • Displacement >5 mm


      • Posterior displacement


      • Angulation >10°


      • Smoking


    • Type II fractures can be treated by lag screw fixation (Type IIB pattern is most likely to benefit from this technique) or C1-C2 arthrodesis.


  • C2 lateral mass fractures



    • Caused by combined lateral bending and axial compression forces


    • Usually treated in cervical orthosis. Chronic pain may be an indication for later arthrodesis.


  • C2 pars fractures (Hangman fracture; Figure 9.9)



    • This represents a traumatic spondylolisthesis of the axis caused by hyperextension and axial loading; involves fractures of bilateral pars interarticularis of C2.






      Figure 9.9 C2 pars (Hangman’s) fracture. Lateral cervical spine radiograph showing fractures through the C2 pars interarticularis (arrows) with resulting C2-C3 subluxation following a hyperextension injury. From Greenspan A, Beltran J. Spine. In: Orthopedic Imaging: A Practical Approach. 6th ed. Philadelphia, PA: Wolters Kluwer Health; 2015:442-510.



    • Levine and Edwards classification categorizes these fractures according to the degree of displacement, angulation, translation, and C2-C3 disk disruption.



      • Type I: nondisplaced, <3 mm translation, no angulation, C2-C3 disk intact


      • Type II: displaced, substantial C2-C3 angulation and >3 mm translation, C2-C3 disk disrupted


      • Type IIA: displaced, severe C2-C3 angulation but no translation, severe C2-C3 ligamentous complex disruption, hinging on the ALL


      • Type III: pars fracture with associated unilateral or bilateral C2-C3 facet dislocation


    • Treatment



      • Type I: usually treated with cervical orthosis


      • Type II: if <5-mm displacement, can be reduced with axial traction and extension and then immobilized in halo; if >5-mm displacement, usually requires surgical stabilization


      • Type IIA: should not be placed in traction because of risk for ligamentous disruption; reduce with hyperextension alone and then halo immobilization


      • Type III: usually requires reduction followed by open reduction and internal fixation of C2, or arthrodesis of C2-C3 or C1-C3


C3-C7 (Subaxial) Injuries



  • Allen-Ferguson classification system categorizes subaxial fractures and dislocations by injury mechanism (Figure 9.10).



    • Compressive flexion


    • Vertical compression


    • Distractive flexion


    • Compressive extension


    • Distractive extension


    • Lateral flexion


  • Subaxial injury classification system builds on the Allen-Ferguson classification system, grading injuries by morphology, discoligamentous complex damage, and extent of neurologic compromise (Table 9.2).



    • Higher scores are more likely to require surgical treatment.


  • Compressive flexion injuries



    • Cervical spine is axially loaded and flexed—indicates compression fractures without neurologic deficits; can often be treated nonoperatively.


    • In severe cases, can develop triangular “teardrop” fracture anteriorly, PLC disruption, and retrolisthesis, causing spinal canal compromise, which requires surgical treatment with anterior decompression and plating with or without posterior fixation.


  • Vertical compression injuries



    • Pure axial loading can cause burst fractures with retropulsion of bony fragments into the canal.


    • Can be treated with anterior decompression and plating with or without posterior fixation


  • Distractive flexion injuries



    • Most common mechanism causing facet dislocations


    • Subaxial facet dislocations (Figure 9.11)



      • Most commonly occur at C5-C6 and C6-C7 levels


      • Unilateral facet dislocations—usually involves <50% translation


      • Bilateral facet dislocations—usually involves >50% translation



        • Often associated with nerve root or spinal cord injuries; 30% of patients have complete spinal cord injuries


        • Use of MRI is controversial; most authors recommend MRI before reduction to rule out herniated disk, which occurs in ˜7% of cases.







          Figure 9.10 Allen-Ferguson system for categorizing subaxial fractures and dislocations by injury mechanism. From Greenleaf R, Richman JD, Altman DT. General principles of vertebral bony, ligamentous, and penetrating injuries. In: Brinker MR, ed. Review of Orthopaedic Trauma. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:406-417.


        • If herniated disk present, proceed with open decompression and arthrodesis via anterior approach.


        • If no herniated disk present and the patient is alert and cooperative, attempt closed reduction with traction.


  • Extension injuries



    • Compressive extension injuries can cause unilateral or bilateral vertebral arch fractures; in most severe cases, there can be anterior ligamentous disruption with anterolisthesis.


    • Distractive extension injuries cause anterior ligamentous disruption and, in most severe cases, injury of the PLC with posterior displacement of the rostral vertebral body into the canal.









      Table 9.2 Subaxial Cervical Spine Injury Classification System Scale





































































      Characteristic

      Points


      Morphology

      No abnormality

      0

      Compression

      1


      Burst

      +1 = 2

      Distractiona

      3

      Rotation/translationb

      4


      Discoligamentous complex

      Intact

      0

      Indeterminatec

      1

      Disruptedd

      2


      Neurologic status

      Intact

      0

      Root injury

      1

      Complete cord injury

      2

      Incomplete cord injury

      3

      Continuous cord compression in setting of neurologic deficit (neuro modifier)

      +1


      a For example, facet perch, hyperextension.

      b For example, facet dislocation, unstable teardrop, or advanced-stage flexion-compression injury.

      c For example, isolated interspinous widening, magnetic resonance imaging signal change only.

      d For example, widening of disk space, facet perch, or dislocation.


      From Vaccaro AR, Hulbert RJ, Patel AA, et al; Spine Trauma Study Group. The subaxial cervical spine injury classification system. A novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex. Spine (Phila Pa 1976). 2007;32:2365-2374.







      Figure 9.11 Facet dislocations. A, Bilateral facet dislocations result from combined hyperflexion and distraction forces. There is associated extensive damage to the posterior ligamentous complex. B, The facets become locked following anterior dislocation of the cephalad vertebral body. The inferior facets of the cephalad vertebra are anterior to the superior facets of the caudal vertebra. C, Lateral cervical spine radiograph showing C5-C6 bilateral locked facets. From Greenspan A, Beltran J. Spine. In: Orthopedic Imaging: A Practical Approach. 6th ed. Philadelphia, PA: Wolters Kluwer Health; 2015:442-510.







      Figure 9.11 (continued)


    • Treatment depends on stability and neurologic compromise, with most severe cases requiring surgical intervention.


  • Lateral flexion injuries



    • Involve direct trauma to the side of the head, leading to distraction forces on the side of impact and compression contralaterally


    • Can result in ligamentous disruption and lateral mass fractures


    • Treatment depends on stability and neurologic compromise.



  • Cervical spinous process avulsion fracture



    • Known as “clay-shoveler fracture”


    • Most common at C7


    • Results from musculoligamentous avulsive forces during sudden flexion/extension activities (eg, shoveling hard dirt)


    • Usually treated nonoperatively; can be excised if patient develops painful nonunion


THORACOLUMBAR SPINE TRAUMA


Etiology

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Dec 19, 2019 | Posted by in ORTHOPEDIC | Comments Off on Spine

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