Updated: 6/5/2022

Pediatric Spondylolysis & Spondylolisthesis

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  • Summary
    • Pediatric Spondylolysis & Spondylolisthesis represent a continuum of disease where there is a fracture of the pars interarticularis (spondylolysis) which may progress to anterior subluxation of one vertebral body anterior to the adjacent inferior vertebral body (spondylolisthesis).
    • Diagnosis of spondylolysis alone can be challenging on imaging and the ideal study is controversial. Radiographs, CT scan, and MRI may all play a role. Spondylolisthesis is diagnosed on a lateral radiograph. 
    • Treatment may be nonoperative or surgical depending on the degree of back pain, malalignment of vertebral bodies, and neurological symptoms.
  • Epidemiology
    • Incidence
      • common
        • up to 6-7% of adolescent athletes
        • implicated in up to 47% of low back pain complaints in this population
    • Demographics
      • higher incidence in Native Americans
    • Anatomic location
      • typically involves pars of L5 and anterolisthesis of L5 relative to S1
    • Risk factors
      • prevalence of spondylolysis may be as high as 47% in certain athletes (gymnasts, weightlifters, football linemen)
      • contact sports and those involving repetitive hyperextension (ex. linebacker)
      • higher sacral table index, pelvic incidence, sacral slope, and lower sacral table angle
  • Etiology
    • Pathophysiology
      • conditions represent a continuum of disease including
        • pars stress reaction
          • defined as sclerosis of pars without complete bone disruption
        • spondylolysis
          • defined as a complete fracture of the pars interarticularis
          • mechanism
            • defects are not present at birth and develop over time (seen in 4-6% if population)
            • usually activity related and occurs from repetitive hyperextension
        • isthmic spondylolisthesis (spondylolytic spondylolithesis)
          • defined as forward translation of one vertebral segment over the one beneath it due to a pars defect
          • risks of progression
            • approximately 15% of individuals with a pars interarticularis lesion have progression to spondylolisthesis
            • the larger the slip the more likely it is to progress
              • > Myerding 2 (>50% slip)
            • dysplastic slips (Wiltse Type I) are more likely to progress
          • severity of current slip
            • correlates most strongly with pelvic incidence
        • spondyloptosis
          • 100% translation of one vertebra over the next caudal vertebra
    • Genetics
      • possible autosomal dominant inheritance pattern
  • Classification
      • Wiltse-Newman Classification
      • Type I
      • Dysplastic
      • Secondary to congenital abnormalities of lumbosacral articulation including mal-oriented or hypoplastic facets, sacral deficiency, poorly developed pars
      • Posterior elements are intact (no spondylolysis)
      • More significant neurologic symptoms
      • Type II-A
      • Isthmic - Pars Fatigue Fx
      • Type II-B
      • Isthmic - Pars Elongation due to healed stress fx
      • Type II-C
      • Isthmic - Pars Acute Fx
      • Type III
      • Degenerative
      • Type IV
      • Traumatic
      • Type V
      • Neoplastic
      • Marchetti-BartolozziClassification
      • Developmental
      • Includes Wiltse I and II
      • Acquired
      • Traumatic, postsurgical, pathologic, degenerative
      • Meyerding Classification
      • Grade I
      • < 25%
      • Grade II
      • 25-50%
      • Grade III
      • 50-75%
      • Grade IV
      • 75-100%
      • Grade V
      • Spondyloptosis
  • Presentation
    • History
      • classic history is healthy active adolescent who presents with acute onset of low back pain with athletic activity
    • Symptoms
      • asymptomatic
        • many cases of spondylolysis are asymptomatic
      • low back pain
        • no association between radiologic grade and clinical presentation
        • symptoms include insidious onset of activity related low back pain
      • leg symptoms
        • buttock pain
        • hamstring tightness (most common) and knee contracture
        • radicular pain (L5 nerve root)
      • listhetic crisis
        • severe back pain aggravated by extension and relieved by rest
        • neurologic deficit
        • hamstring spasm
      • bowel and bladder symptoms
        • rare
      • cauda equina syndrome (rare)
    • Physical exam
      • inspection
        • high grade/dysplastic patients may develop "heart shaped buttocks" due to sacral prominence
        • flattened lumbar lordosis
        • palpation
          • palpable step off of spinous process
      • motion
        • limitation of lumbar flexion and extension
        • measure popliteal angle to evaluate for hamstring tightness
      • neurovascular
        • straight leg raise may be positive
        • rectal exam if bowel and bladder symptoms present
      • provocative tests
        • pain with single-limb standing lumbar extension
      • gait
        • may walk with a crouched gait when symptoms severe
  • Imaging
    • Pars stress reaction & spondylolysis
      • radiographs
        • indications
          • AP and lateral indicated in all patients with concern for spondylolysis and spondylolithesis
        • AP view
          • may see sclerosis of the stress reaction
        • lateral view
          • may show defect in pars in 80%
        • oblique view
          • views may show sclerosis and elongation in pars interarticularis (scotty dog sign)
          • some studies have shown that oblique does not provide more diagnostic information than AP and lateral radiographs but does increase radiation exposure
      • CT
        • inidcations
          • best study to delineate anatomy of lesion
        • findings
          • pars stress reaction will show up as sclerosis on x-rays and CT scan
      • single photon emission computer tomography (SPECT)
        • indications
          • previously considered the best diagnostic adjunct when plain radiographs are negative; however, now rarely performed given unnecessary radiation exposure
          • can also detect osteoid osteomas, sacroiliitis, osteitis pubis, and disc herniation
        • techniques
          • combines technique of bone scan with CT in order to help localize an area of abnormal activity seen on bone scan
      • MRI
        • indications
          • negative ragdiographs with high suspicion
          • very acute presentation
          • any neurological deficits
        • sensitivity & specificity
          • recent studies have shown MRI to be as sensitive and specific as SPECT, with the additional benefit of avoiding radiation exposure
      • bone scan
        • indications
          • excellent screening tool for low back pain in children or adolescents
        • sensitivity & specificity
          • most sensitive (however lesion may be cold)
    • Spondylolisthesis
      • radiographs
        • views
          • lateral x-ray used to measure slip angle and grade.
          • flexion and extension radiographs used to evaluate instability
        • measurements
          • slip grade
            • slippage on plain lateral radiographic imaging measured in accordance to the vertebra below
              • the caudal vertebra is divided into four parts
                • Grade I means a translation of the cranial vertebra of up to 25%
                • Grade II of up to 50%
                • Grade III of up to 75%
                • Grade IV up to 100%
                • Grade V describes the ptosis of the cranial vertebra
          • slip angles
            • methodology to determine slip angle
            • most important determinant for nonunion and pain
            • angle >45-50 degrees associated with greater slip progression, instability, and development of post-op pseudo
          • pelvic incidence
            • pelvic incidence = pelvic tilt + sacral slope
            • a line is drawn from the center of the S1 endplate to the center of the femoral head
            • a second line is drawn perpendicular to a line drawn along the S1 endplate, intersecting the point in the center of the S1 endplate
            • the angle between these two lines is the pelvic incidence (see angle X in figure above)
            • correlates with severity of disease
            • pelvic incidence has direct correlation with the Meyerding–Newman grade
          • pelvic tilt
            • pelvic tilt = pelvic incidence - sacral slope
            • a line is drawn from the center of the S1 endplate to the center of the femoral head
            • a second vertical line (parallel with side margin of radiograph) line is drawn intersecting the center of the femoral head
            • the angle between these two lines is the pelvic tilt (see angle Z in figure above)
          • sacral slope
            • sacral slope = pelvic incidence - pelvic tilt
            • a line is drawn parallel to the S1 endplate
            • a second horizontal line (parallel to the inferior margin of the radiograph) is drawn
            • the angle between these two lines is the sacral slope (see angle Y in the figure above)
      • CT
        • best study to diagnose and delineate anatomy of pars defect
      • MRI
        • indicated if neurologic symptoms present
        • useful to diagnose associated central and foraminal stenosis
  • Treatment
    • Nonoperative
      • observation alone (no activity limitations)
        • indications
          • asymptomatic patients
            • regardless of slip grade which does not correlate with clinical presentation
        • return to in contact sports is controvesial
          • limited evidence to guide surgeons following surgical management, decision must be individualized
          • some data shows patients who stop sports for at least 3 months have improved outcomes compared to those who continue to play
        • outcomes
          • typically do well and remain asymptomatic
      • physical therapy & activity restriction
        • indications
          • symptomatic isthmic spondylolysis
          • symptomatic low-grade spondylolisthesis
        • technique
          • physical therapy should be done for 6 months and include
            • hamstring stretching
            • pelvic tilts
            • abdominal strengthening
        • outcomes
          • most improve and do not require surgery
          • watch low grade dysplastic carefully as there is a higher chance of progression
      • bracing for 6 to 12 weeks
        • indications
          • acute pars stress reaction spondylolysis
          • isthmic spondylolysis that has failed to improve with physical therapy
          • low grade spondylolisthesis that has failed to improve with physical therapy
        • technique
          • typically a TLSO
        • outcomes
          • brace immobilization is superior to activity restriction alone for acute stress reaction spondylolysis
    • Operative
      • pars interarticularis repair
        • indications
          • L1 to L4 isthmic defect that has failed nonoperative management
          • multiple pars defects
        • outcomes
          • typically superior to fusion procedures, preserves motion
      • L5-S1 posterolateral fusion, +/- ALIF, +/- sacroiliac fusion
        • indications
          • L5 spondylolysis that has failed nonoperative treatment
          • low grade spondylolisthesis (Myerding Grade I and II) that
            • has failed nonoperative treatment
            • is progressive
            • has neurologic deficits
            • is dysplastic due to high propensity for progression
        • return to sport
          • some evidence to support that ALIF may help return to competetitive sports
          • most surgeons allow return to noncontact sports 3-6 months following fusion and return to contact sports 6-12 months (controversial)
        • outcomes
          • patients typically do well and return to sport in 3-6 months
      • L4-S1 posterolateral fusion, +/- reduction, +/- sacroiliac fusion, +/- ALIF
        • indications
          • high grade spondylolytic spondlylisthesis (Meyerding Grade III, IV, V)
          • reduction is extremely controversial with no accepted guidelines
        • outcomes
          • patients typically do well but may have greater motion limitations with multi-level fusion
          • over-aggressive reduction techniques may result in neurologic impairments
  • Techniques
    • Par interarticularis repair
      • approach
        • posterior midline approach to lumbar spine
      • technique
        • repair pars defect with screw fixation, tension wiring, or screw and sublaminar hook technique
        • decompression indicated if clinical symptoms of stenosis
        • contraindications
          • disc degeneration (obtain MRI for sx planning)
    • L5-S1 posterolateral fusion +/- ALIF
      • approach
        • posterior midline approach to lumbar spine
      • technique
        • decompression only indicated if clinical symptoms of stenosis or radiculopathy
        • in-situ fusion with bone grafting / with or without instrumentation
      • postoperative
        • usually postoperative immobilization in a TLSO
    • L4-S1 posterolateral fusion, +/- reduction+/- sacroiliac fusion, +/- ALIF
      • approach
        • posterior midline approach to lumbar spine
      • technique
        • reduction
          • reduction may be done with instrumentation or positioning
          • pros of reduction
            • can restore sagittal alignment and reduce lumbosacral kyphosis
          • cons
            • risk of significant complications (8-30%) including
            • L5 is the most common nerve root injury with reduction
            • sexual dysfunction
            • catastrophic neurologic injury
        • fusion/decompression
          • usually instrumented
          • the addition of decompression and anterior-posterior (360 deg) fusion is associated with more in-hospital complications
            • the use of interbody cages in this population has decreased significantly, while costs associated with treatment in general have increased over time
  • Complications
    • Neurologic deficits
      • consider neuromonitoring during reduction, especially in a high-grade slip
      • L5 n. root injury is the most common neuro cx
    • Pseudoarthrosis
    • Slip Progression
    • Hardware failure
  • Prognosis
    • Most symptomatic patients can be successfully managed nonoperatively
    • In patients who fail non-operative management, spinal fusion results in 90% success rates
    • Return to sports is controversial

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Flashcards (64)
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Questions (19)

(OBQ19.157) A 13-year-old male presents with lower back pain and hamstring tightness of 1-month duration. The patient underwent a routine radiograph which is demonstrated in figure A. Which of the following factors are associated with the progression of this condition?

QID: 214059

Acute onset of symptoms



Presentation after adolescent growth spurt



Male gender



> Myerding 2 grade spondylolisthesis on presentation



Decreased lumbosacral kyphosis




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(OBQ13.141) A 13-year-old girl presents with back pain for 6 months. Figures A and B are SPECT scan and CT images taken at the time of presentation. What is the most likely diagnosis?

QID: 4776

Osteoid osteoma



Bone island






Osteoblastic metastases



Aneurysmal bone cyst



L 2 B

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(OBQ11.61) A 12-year-old gymnast has had progressive low back and buttock pain refractory to conservative management for two years. A sagittal MRI is shown in Figure A. Surgical management with reduction of L5 on S1 would most likely lead to which of the following neurologic complications?

QID: 3484

Decreased patellar reflexes



Weakness to hip flexion



Weakness to great toe extension



Weakness to knee extension



Weakness to ankle plantar flexion



L 3 B

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(OBQ09.15) A 17-year-old high school football lineman was diagnosed with the condition shown in the Figure A radiograph. He continues to have pain despite 6 months of wearing a custom lumbar spine orthotic (LSO) and avoiding all sports activities. His physical exam is notable for pain with single-limb standing lumbar extension and a normal neurologic exam. How would the surgical management differ if this condition occurred at L3 instead of L5?

QID: 2828

Pars interarticularis repair is indicated



Lumbosacral fusion is indicated



Gill procedure is indicated



Combined anterior interbody fusion and posterior decompression is indicated



Iliac crest bone grafting is indicated



L 2 C

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(OBQ08.55) A 14-year-old soccer player has a history of intermittent low back pain. He reports for the last 4 months he has had no symptoms or limitations in his athletic activity. Treatment should include?

QID: 441

a thoracolumbar orthosis



in situ L5-S1 bilateral posterolateral fusion



repair of pars defect wih screw fixation



limitation of athletic activity



observation with no restriction of physical activity



L 2 C

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(OBQ07.144) A 12-year-old girl presents with 6 months of moderate but persistent lower back pain. She has increased pain when she stands upright on one leg as well as shooting pain when she tries to bend down to touch her toes. A straight leg raise test is negative but it is noted that her hamstrings are tight. She has tried NSAIDs and PT, which have provided her with limited relief. Upright radiographs are shown in Figure A. What is the next most appropriate treatment?

QID: 805

Repair of L5-S1 pars with tension wiring



Posterior instrumentation and fusion from L5-S1 without reduction of the deformity



Posterior instrumentation and fusion from L5-S1 with reduction of the deformity



Posterior instrumentation and fusion from L4-S1



A trial of TLSO for 6 weeks



L 5 C

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(SAE07PE.42) A 14-year-old boy reports a 4-month history of increasing backache with difficulty walking long distances. His parents state that he walks with his knees slightly flexed and is unable to bend forward and get his hands to his knees. He denies numbness, tingling, and weakness in his legs and denies loss of bladder and bowel control. A lateral radiograph of the lumbosacral spine is shown in Figure 18. What is the best surgical management for this condition?

QID: 6102

Vertebrectomy of L5



Posterior spinal fusion with or without instrumentation from L4 to S1



Posterior spinal fusion without instrumentation from L5 to S1



Anterior spinal fusion from L4 to L5



Direct repair of the spondylolysis defect



L 2 E

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(OBQ07.71) What additional diagnostic test is most sensitive to diagnose pediatric spondylolysis when AP and lateral radiographs are normal.

QID: 732

Flexion-extension lateral radiographs



Oblique radiographs of the of the lumbosacral spine



Single photon emission computed tomography (SPECT)



Indium-labeled bone scan






L 2 D

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(OBQ06.10) A 13-year-old gymnast reports the acute onset of low back pain that began four weeks ago. Radiographs are unremarkable. A single-photon-emission-computer-tomography (SPECT) is shown in Figure A. Initial treatment should consist of?

QID: 21

Bracing with a molded lumbosacral orthosis



Aggressive physical therapy



CT guided biopsy



In-situ posterolateral fusion of L5-S1



Epidural steroid injection



L 2 D

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