ThoracolumbarThoracolumbar and and Lumbar Burst FracturesLumbar Burst Fractures

SussanSussan Salas, MDSalas, MD

Thomas Jefferson University Hospital Thomas Jefferson University Hospital Department of Neurological SurgeryDepartment of Neurological Surgery

ThoracolumbarThoracolumbar/Lumbar Burst /Lumbar Burst Fractures: OverviewFractures: Overview

EpidemiologyEpidemiologyAnatomyAnatomyInitial AssessmentInitial AssessmentImagingImagingInjury Mechanism/BiomechanicsInjury Mechanism/BiomechanicsFracture ClassificationFracture ClassificationTreatment Options: Operative vs. NonTreatment Options: Operative vs. Non--operative Managementoperative Management

Epidemiology Epidemiology

79,000 spinal fractures in U.S. each year 79,000 spinal fractures in U.S. each year –– 72.5% 72.5% involve thoracic or lumbar spine involve thoracic or lumbar spine [1,2][1,2]

Most common site of injury is Most common site of injury is thoracolumbarthoracolumbarjunctionjunction

Mechanical transition zone between rigid thoracic Mechanical transition zone between rigid thoracic and more mobile lumbar spine and more mobile lumbar spine [3[3--5]5]

Lumbar spine more prone to injuryLumbar spine more prone to injuryAbsence of ribs, transition from Absence of ribs, transition from kyphotickyphotic to to lordoticlordotic posture, posture, sagitallysagitally oriented facet joints oriented facet joints [6][6]

Operative versus nonOperative versus non--operative mgmt: controversyoperative mgmt: controversy

AnatomyAnatomy

Vertebral column: 29 vertebrae organized in 4 curves:

2 primary curves present at birth: thoracic and sacral(kyphosis)2 compensatory curves - result of adaptation to upright posture: cervical and lumbar (lordosis)

AnatomyAnatomyT spine: made rigid by ribcage articulations (ligamentous support); facet joints in coronal plane limit flexion/extensionL spine: facet joints in sagittal plane increase flexion/extension but decrease lateral bending/rotationTL junction: facet joints in oblique orientation; provide support and resistance to 35-45% of torsional and shear forces on spine

Initial AssessmentInitial AssessmentABCs & ImmobilizationABCs & Immobilization: : patients should be patients should be immobilized until stability of fracture can be immobilized until stability of fracture can be assessed adequately assessed adequately –– avoid loss/worsening of avoid loss/worsening of neurological deficits neurological deficits [4][4]

Neurological examNeurological exam: : performed as soon as the performed as soon as the patient is patient is hemodynamicallyhemodynamically stable: motor, sensation, stable: motor, sensation, DTRsDTRs, digital rectal exam , digital rectal exam [10][10]

Neurologic deficits from TL Neurologic deficits from TL fxsfxs can involve can involve spinal cord or spinal cord or caudacauda equinaequina70% of 70% of thoracolumbarthoracolumbar injuries do not have injuries do not have associated neurologic deficits associated neurologic deficits [2][2]

Initial Assessment: Initial Assessment: Motor Examination

Upper extremityC5-shoulder abductionC6-wrist extensionC7-wrist flexionC8-finger flexionT1-finger abduction

Initial Assessment:Initial Assessment:Motor Examination

Lower extremityL1-hip flexionL2-hip adduction L3-knee extension L4-ankle dorsiflexionL5-toe extension

Initial Initial Assessment:Assessment:DermatomesDermatomes

Initial Assessment:Initial Assessment:Classification of injury

American Spinal Injury Association (ASIA)

A = Complete – No Sacral Motor / Sensory B = Incomplete – Sacral sensory sparing C = Incomplete – Motor Sparing (<3) D = Incomplete – Motor Sparing (>3) E = Normal Motor & Sensory

E

Imaging: XImaging: X--RaysRays

AP and lateralAP and lateral::AP view: pedicles, AP view: pedicles, VBsVBs, disc , disc spaces, spaces, spinousspinous processesprocessesLateral view: VB heights, Lateral view: VB heights, disc space relations, VB disc space relations, VB alignment, alignment, paraspinalparaspinalswellingswelling

Imaging: XImaging: X--rayray

In the presence of In the presence of injury, the entire spine injury, the entire spine should be imaged to should be imaged to rule out noncontiguous rule out noncontiguous injuriesinjuriesDegree of Degree of kyphosiskyphosis can can be measured using be measured using Cobb Measurement.Cobb Measurement.

Imaging: CTImaging: CT

CT yields more diagnostic information than CT yields more diagnostic information than plain radiographs regarding extent of bony plain radiographs regarding extent of bony injury injury [6,12][6,12]

Imaging: MRIImaging: MRI

MRI allows MRI allows visualization of soft visualization of soft tissue components of tissue components of spinal injuries spinal injuries [6][6]

Useful at Useful at thoracothoraco--lumbar junction due lumbar junction due to variable location of to variable location of conusconus medullarismedullaris

Injury Mechanism/BiomechanicsInjury Mechanism/Biomechanics

Gravity exerts continual axial load on the Gravity exerts continual axial load on the vertebral columnvertebral columnBodyBody’’s center of gravity is approx 4cm anterior s center of gravity is approx 4cm anterior to first sacral vertebra to first sacral vertebra –– results in ventral results in ventral bending vector acting on spinal columnbending vector acting on spinal columnPosterior Posterior ligamentousligamentous complex complex acts as dorsal acts as dorsal tension band to counteract these forces tension band to counteract these forces -- net net sum of vectors acting on spine equal zerosum of vectors acting on spine equal zeroEssential to prevent change in spineEssential to prevent change in spine’’s s sagittalsagittalalignment alignment

Injury Mechanism/BiomechanicsInjury Mechanism/BiomechanicsPLCPLC: : interspinousinterspinousligaments and ligaments and ligamentumligamentum flavumflavumTrauma resulting in Trauma resulting in spinal ligament/osseous spinal ligament/osseous structure disruption may structure disruption may change net vector sum change net vector sum acting on spine from acting on spine from zero, resulting in zero, resulting in potential for spinal potential for spinal imbalanceimbalance

Injury Mechanism/BiomechanicsInjury Mechanism/BiomechanicsWhiteside Whiteside [9][9]: analogy of construction crane : analogy of construction crane Failure of the cable leads to the crane falling Failure of the cable leads to the crane falling forward forward –– in spine, illustrated by characteristic in spine, illustrated by characteristic kyphotickyphotic deformity seen with unstable burst deformity seen with unstable burst fxsfxs

Fracture ClassificationFracture Classification

Fracture classification allows organization and Fracture classification allows organization and treatment of fractures through protocols treatment of fractures through protocols developed to maximize patient outcomesdeveloped to maximize patient outcomes

Most classification schemes based on criteria for Most classification schemes based on criteria for describing describing stabilitystability

Fracture Classification: Fracture Classification: HoldsworthHoldsworth

HoldsworthHoldsworth [15]: [15]: twotwo--column column model of spine stability model of spine stability (1960s). Separated spine into (1960s). Separated spine into anterior weightanterior weight--bearing bearing column (a) and posterior column (a) and posterior tensiontension--bearing column (b) bearing column (b) Burst fractures unstable if Burst fractures unstable if PLC is disruptedPLC is disrupted

Fracture Classification: DenisFracture Classification: Denis

DenisDenis [3]: three[3]: three--column classification of spinal column classification of spinal fractures (1980s). Injury to middle column was fractures (1980s). Injury to middle column was necessary and sufficient to create instabilitynecessary and sufficient to create instabilityBased classification on results of biomechanical Based classification on results of biomechanical studies demonstrating that isolated rupture of studies demonstrating that isolated rupture of PLC is insufficient to create instabilityPLC is insufficient to create instability

Fracture Classification: DenisFracture Classification: Denis

Divides spinal fractures into minor and major Divides spinal fractures into minor and major injuriesinjuries

Minor injuries: fractures of transverse process, Minor injuries: fractures of transverse process, pars pars interarticularisinterarticularis, , spinousspinous processprocessMajor injuries:Major injuries:

Fracture type Column

Anterior Middle Posterior

Compression Compression Intact Intact , or distractionBurst Compression Compression IntactSeat-belt type Intact Distraction Fracture dislocation

Compression, rotation , shear

Distraction , rotation , shear

Fracture Classification: DenisFracture Classification: Denis

Compression FractureCompression Fracture Burst FractureBurst Fracture

Fracture Classification: DenisFracture Classification: Denis

SeatSeat--belt typebelt type Fracture dislocationFracture dislocation

Fracture Classification: DenisFracture Classification: DenisDenisDenis’’ 3 types of instability:3 types of instability:

Mechanical (1Mechanical (1stst degree) degree) –– may result in late may result in late kyphotickyphoticdeformity. Require external or operative stabilization.deformity. Require external or operative stabilization.Neurologic (2Neurologic (2ndnd degree) degree) –– retropulsionretropulsion of bone of bone fragments predispose patients to increased risk for fragments predispose patients to increased risk for neurologic injury. Controversy re: operative neurologic injury. Controversy re: operative stabilization.stabilization.Mechanical/neurologic (3Mechanical/neurologic (3rdrd degree) degree) –– develop after develop after burst burst fxfx w/neurow/neuro deficit or fracture/dislocation. deficit or fracture/dislocation. Highly unstable > require operative decompression Highly unstable > require operative decompression and stabilization.and stabilization.

Fracture Classification: Fracture Classification: McCormackMcCormack

McCormackMcCormack [17][17]: load: load--sharing classification, sharing classification, designed specifically for designed specifically for thoracolumbarthoracolumbar burst burst fxsfxs(1994)(1994)Uses point system: grades amount of VB Uses point system: grades amount of VB comminutioncomminution, displacement of fracture fragments, , displacement of fracture fragments, degree of degree of kyphosiskyphosis (1(1--9 points)9 points)

Score 1 point 2 points 3 points

Sagittal collapse 30% >30% 60%

Shift 1mm 2mm >2mm

Correction 3 degrees 9 degrees 10 degrees

Fracture Classification: Fracture Classification: McCormackMcCormack

With McCormack, patients with >6 points have With McCormack, patients with >6 points have a large void or gap, resulting in least supportive a large void or gap, resulting in least supportive anterior and middle columns and predisposing anterior and middle columns and predisposing posterior instrumentation for failureposterior instrumentation for failure

Original goal was to predict failure of shortOriginal goal was to predict failure of short--segment posterior fixation for burst segment posterior fixation for burst fxsfxs ––prescribes that injuries with high scores should prescribes that injuries with high scores should undergo supplemental anterior column supportundergo supplemental anterior column support

Fracture Classification: TLICSFracture Classification: TLICS

TLICS systemTLICS system [13] [13]

designed by the Spine designed by the Spine Trauma Study Group Trauma Study Group (2008). Based on 3 (2008). Based on 3 aspects: aspects:

morphology of the injurymorphology of the injuryintegrity of the PLCintegrity of the PLCneurological status of the neurological status of the patientpatient

Injury morphology

Compression 1Burst 1

Translation rotation 3Distraction 4

PLC integrity

Intact 0Indeterminate 2

Disrupted 3Neurological status

Intact 0Nerve root injury 2

Complete 2Incomplete 3

Fracture Classification: TLICSFracture Classification: TLICS

TLICS determination for surgery: TLICS determination for surgery: <3 points can be treated non<3 points can be treated non--operativelyoperatively>5 points usually require surgical intervention>5 points usually require surgical intervention= 4 points can be treated w/or = 4 points can be treated w/or w/o surgeryw/o surgery

TLICS determination of surgical approach:TLICS determination of surgical approach:Incomplete + anterior compression = ANTIncomplete + anterior compression = ANTIncompetent PLC = POSTIncompetent PLC = POSTNeurological Neurological deficit + incompetent PLC = ANT + deficit + incompetent PLC = ANT + POSTPOST

Treatment OptionsTreatment Options

Controversy regarding operative vs. nonControversy regarding operative vs. non--operative management, surgical approachoperative management, surgical approach

Treatment based on maximizing neurologic Treatment based on maximizing neurologic recovery and preventing neurologic decline recovery and preventing neurologic decline ––identify identify unstable fracturesunstable fractures

NonNon--operative Managementoperative Management

Most fractures in Most fractures in thoracolumbarthoracolumbar/lumbar region /lumbar region consist of compression, burst fractures, and consist of compression, burst fractures, and isolated dorsal column fractures isolated dorsal column fractures –– stable stable fxsfxsCompression Compression fxsfxs: stable if PLC, along with : stable if PLC, along with dorsal vertebral body, is not disrupted (Denis) dorsal vertebral body, is not disrupted (Denis) ––bracingbracingBurst Burst fxsfxs: stable if no PLC injury/dorsal element : stable if no PLC injury/dorsal element fxfx. Neurologically intact patient > bracing. Neurologically intact patient > bracing

NonNon--operative Managementoperative Management

Mumford et alMumford et al

41 pts with 41 pts with thoracothoraco--lumbar burst lumbar burst fxsfxs w/o w/o neurological deficit treated conservativelyneurological deficit treated conservativelyAt injury, canal compromise averaged 37% At injury, canal compromise averaged 37% -- at 2 at 2 years years f/uf/u, 2/3 resolution of fragments occluding canal, 2/3 resolution of fragments occluding canalOutcome evaluation: 49% patients reported excellent Outcome evaluation: 49% patients reported excellent outcomes relative to pain and functionoutcomes relative to pain and functionProgression of body collapse on imaging averaged 8%Progression of body collapse on imaging averaged 8%1 pt developed neurologic deterioration prompting 1 pt developed neurologic deterioration prompting surgery surgery –– all other pts remained neurologically intactall other pts remained neurologically intact

NonNon--operative Managementoperative Management

Cantor et alCantor et al18 18 neurologically intactneurologically intact patients with burst patients with burst fxsfxs w/o w/o PLC disruption PLC disruption –– treated with early ambulation treated with early ambulation w/bracingw/bracingKyphosisKyphosis: 19 degrees at time of injury, 20 degrees at : 19 degrees at time of injury, 20 degrees at f/uf/uVB height loss: 36% on presentation, max change 5% at VB height loss: 36% on presentation, max change 5% at f/uf/uAt f/u15 pts rated their pain as little or none, 17 pts had At f/u15 pts rated their pain as little or none, 17 pts had little or no restriction of activity.little or no restriction of activity.CT scan 1 yr after injury in 8 pts showed >50% CT scan 1 yr after injury in 8 pts showed >50% resorptionresorption of of retropulsedretropulsed boneboneNo patient had deterioration of neurological function.No patient had deterioration of neurological function.

Surgical TreatmentSurgical Treatment

Surgical Treatment Surgical Treatment –– 3 components:3 components:Neural DecompressionNeural DecompressionStabilizationStabilizationFusionFusion

Surgical treatment: DecompressionSurgical treatment: DecompressionTL and TL and LspineLspine fxfx w/ w/ neuroneuro deficit have significantly deficit have significantly higher recovery rate when treated with surgery. higher recovery rate when treated with surgery. Primary goal: decompression of the spinal canal Primary goal: decompression of the spinal canal [4,7][4,7]

Anterior, compared to posterior and Anterior, compared to posterior and posterolateralposterolateraldecompression has a higher rate of neurologic decompression has a higher rate of neurologic improvement (88% vs. 64%) and recovery of B&B improvement (88% vs. 64%) and recovery of B&B function (69% vs. 33%).function (69% vs. 33%).[8,18][8,18]

Anterior decompression via Anterior decompression via corpectomycorpectomy: maximal : maximal degree of canal decompressiondegree of canal decompressionTreatment of low lumbar (L3Treatment of low lumbar (L3--5) burst 5) burst fxfx require require posterior approachposterior approach

Surgical treatment: DecompressionSurgical treatment: Decompression

Timing of surgery in patients w/burst Timing of surgery in patients w/burst fxsfxsw/neurologic deficit is unclearw/neurologic deficit is unclear

Most clinical studies have shown no correlation b/w Most clinical studies have shown no correlation b/w timing and amount of neurologic recovery timing and amount of neurologic recovery [7,11][7,11]

One study (One study (MirzaMirza et al, 1999) showed improved et al, 1999) showed improved neurologic recovery w/surgery within 72 hrs vs. 10neurologic recovery w/surgery within 72 hrs vs. 10--14 days 14 days [16][16]

Patients w/progressive deficit need Patients w/progressive deficit need emergent emergent decompressiondecompression

Surgical Treatment: StabilizationSurgical Treatment: StabilizationPrimary role of surgical Primary role of surgical instrumentation: restore instrumentation: restore immediate stability and correct immediate stability and correct acute deformitiesacute deformitiesAnterior stabilization: Anterior stabilization:

Advantage: limits fusion to Advantage: limits fusion to level above and below level above and below injuryinjuryDisadvantage: risk of Disadvantage: risk of vascular and visceral injuryvascular and visceral injury

Surgical Treatment: StabilizationSurgical Treatment: StabilizationOptions for posterior Options for posterior stabilization: rods secured by stabilization: rods secured by screws, hooks, or wiresscrews, hooks, or wiresPedicle screw system: instrument Pedicle screw system: instrument two levels above and below two levels above and below injuryinjuryShort segment stabilization (one Short segment stabilization (one level above and below) has high level above and below) has high rate of construct failure. If spinal rate of construct failure. If spinal flexibility is priority, can be flexibility is priority, can be combined w/anterior combined w/anterior instrumentation instrumentation [17,19][17,19]

Surgical Treatment: FusionSurgical Treatment: FusionLong term goal of instrumentation: maintain Long term goal of instrumentation: maintain proper spinal alignment and stability until bone proper spinal alignment and stability until bone fusion occurs fusion occurs [9,19] [9,19]

Without solid fusion, metallic implants eventually Without solid fusion, metallic implants eventually breakbreakIn order for fusion to occur, bone graft or graft In order for fusion to occur, bone graft or graft replacement must have:replacement must have:

OsteogenicityOsteogenicityOsteoinductivityOsteoinductivityOsteoconductivityOsteoconductivity

Surgical Treatment: FusionSurgical Treatment: FusionAnterior fusion: Anterior fusion:

AutograftAutograft (Iliac crest) (Iliac crest) Allograft (Femoral or Allograft (Femoral or humeral shaft)humeral shaft)Synthetic cageSynthetic cage

Posterior fusion: Posterior fusion: DecorticationDecortication of of exposed bone elementsexposed bone elementsImplantation of bone Implantation of bone fragment or bone matrixfragment or bone matrix

ThoracolumbarThoracolumbar/Lumbar Burst /Lumbar Burst Fractures: OverviewFractures: Overview

EpidemiologyEpidemiologyAnatomyAnatomyInitial AssessmentInitial AssessmentImagingImagingInjury Mechanism/BiomechanicsInjury Mechanism/BiomechanicsFracture ClassificationFracture ClassificationTreatment Options: Operative vs. NonTreatment Options: Operative vs. Non--operative Managementoperative Management

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