Neurosurgery notes/Spine/Deformity/Thoracic and lumbar deformity/Scoliosis/Spondylolisthesis-induced scoliosis

Spondylolisthesis-induced scoliosis

View Details
logo
Parent item
Scoliosis

Numbers:

  • Association of scoliosis and spondylolisthesis is between 15% and 48%.
    • Up to 48% of children with spondylolisthesis developed at least 5° Cobb of scoliosis.
    • Between 18% and 48% young patients with lumbar spondylolisthesis have scoliosis
      • 60% of dysplastic spondylolisthesis in young patients have scoliosis
  • The rate of scoliosis in individuals with symptomatic spondylolisthesis was almost twice that of those with asymptomatic slips.
    • Asymptomatic spondylolisthesis: scoliosis incidence of 23.8%,
    • Symptomatic spondylolisthesis: 43.1% in symptomatic cases.
  • It is a common notion that the highest occurrence of scoliosis associated with spondylolisthesis is at the lumbar level, both in adolescent and adult patients,
    • Typically presenting with curve angles lower than 15° Cobb and mild rotation.

Three types of spondylolisthesis induced scoliosis:

Spasm Scoliosis (SS)
  • Cause:
    • Due to muscle spasm and nerve irritation associated with symptomatic spondylolisthesis.
    • Can be compared to scoliosis caused by other painful spinal pathologies, such as disk herniation or osteoid osteoma.
  • Characteristics:
    • SS typically presents with a tilted spine, a long curve span, and little to no vertebral rotation.
    • The curve angle is often low, usually no more than 20° Cobb, and it shows almost no pedicle rotation on radiographic exams.
      • These are considered functional curves.
    • The age of patients with olisthetic scoliosis (OS) was significantly higher than those with spasm scoliosis (SS) (18.9 ± 7.8 years vs. 12.7 ± 2.9 years, P = 0.029).
  • Management
    • Spasm scoliosis is often completely or largely resolved after successful treatment of the symptomatic spondylolisthesis, which relieves pain and muscle spasm.
      • Resolution can sometimes take a year or more post-operation. If the muscle spasm mechanism is prominent in the curve's genesis, pain resolution can resolve the antalgic scoliosis.
    • Early surgical intervention for lytic spondylolisthesis with spasm/olisthetic scoliosis, solely to resolve the "asymmetric ring" or prevent worsening curves, is not universally advocated.
Olisthetic Scoliosis (OS)
  • Definition:
    • Spinal curvature that arises in association with spondylolisthesis
  • Cause:
      • Olisthetic scoliosis is linked to the asymmetric slippage and sinking of the olisthetic vertebra, particularly L5, which can translate in both sagittal and coronal planes and rotate around its vertical axis. → forms an asymmetric "foundation" that leads to a rotatory deformity of the spine above → rotation causes traction on the intervertebral disk → the vertebral body to "sink" → loss of static balance in the upper spine.
      • While distinct, a spasm factor may also be present alongside the rotational cause.
      • Iliolumbar ligaments play a role in stabilising L5, and the incidence of scoliosis associated with spondylolisthesis is greater when the pars defect is at the L4-L5 level compared to L5-S1, possibly due to the absence of these stabilizing ligaments at L4-L5.
      notion image
  • Characteristics:
      • Patients with scoliosis associated with dysplastic spondylolisthesis often have a significantly higher slip percentage (70.8% ± 22.7% vs. 52.7% ± 19.8%, P = 0.005) and a smaller Dubousset’s lumbosacral angle (61.8° ± 15.4° vs. 70.8° ± 11.2°, P = 0.025) compared to those without scoliosis.
        • Most patients have a L5/S1 spondylolisthesis with slip percentages exceeding 50% (range: 51%–95%).
      • Apex of the compensatory curve is usually located in the lumbar region with mild vertebral rotation (typically no more than Grade I Nash-Moe Method). It can be associated with irradiating pain.
      • Curve demonstrates more rotation than is usual in an idiopathic scoliosis of similar magnitude
        • Maximal torsion often at the spondylolytic vertebra itself, not the apical vertebra.
      notion image
      notion image
  • Resolution:
    • Resolution of olisthetic scoliosis after spondylolisthesis surgery is less common than with spasm scoliosis, with one study reporting resolution in 44.4% of cases.
    • Failed resolution may be related to older age at surgery, a larger Cobb angle, and more severe L5 rotation.
    • For OS, correction of L5 rotation and tilt during the reduction procedure of the spondylolisthesis is important, as fixing the "foundation" in an asymmetric position without correcting rotation can lead to no relief or even progression of the scoliosis.
  • Management
    • Conservative Treatment:
      • indication
        • For symptomatic grade I/II lytic spondylolisthesis
        • This approach is also suggested for asymptomatic spondylolisthesis when the associated scoliosis is not of surgical interest.
      • Options
        • Conservative measures like brace immobilisation for 45–60 days have shown to resolve pain in 80% of patients and, in a minority (20%), lead to resolution or reduction of associated low-grade scoliosis curves.
    • Surgery
      • Treatment of spondylolisthesis should be performed first, then the scoliosis is then observed for a period of time (e.g., 3–12 months or often a year or more)
        • Options:
          • Lumbosacral Fusion:
          • In Situ Fusion:
            • Posterior in situ lumbosacral fusion, sometimes followed by a period of postoperative external immobilisation (e.g., a double pantaloon Risser cast), has been utilised and has shown to lead to curve improvement or resolution in many cases.
            • However, instances of curve progression have also been noted in this uninstrumented group.
          • Instrumented Fusion with Reduction and Decompression:
            • Other approaches include posteriorly instrumented fusions, sometimes combined with efforts at reduction and decompression (e.g., L5-S1 discectomy, decompressive sacroplasty, transforaminal lumbar interbody fusion (TLIF), L5 laminotomy).
          • Correction of L5 Rotation and Tilt:
            • For olisthetic scoliosis specifically, it is crucial to correct the rotation and tilt of the L5 vertebra during reduction procedures of the spondylolisthesis.
            • This may help to better relieve the scoliosis and prevent curve progression.
            • Failure to correct this rotation might lead to no relief or even progression of the scoliosis.
        notion image
         
      • Outcome
        • Following successful surgical treatment of spondylolisthesis, many cases of olisthetic scoliosis show spontaneous improvement or complete resolution. This is particularly true for long sweeping curves with little or no apical rotation.
        • If the scoliosis persists or progresses after spondylolisthesis treatment, it should be re-evaluated and then treated according to the principles typically applied to "idiopathic scoliosis".
        • Older teenagers and those with substantial apical rotation in their scoliosis may experience curve progression, although additional surgical treatment for the scoliosis may not always be necessary.
      • Factors that prevent resolution of scoliosis after listhesis surgery
        • Scoliosis being "Independent" (Non-Spondylolisthesis-Induced):
          • While spondylolisthesis treatment might relieve any co-existing spondylolisthesis-induced scoliosis, the underlying independent scoliosis will remain and should be re-evaluated and treated according to its own principles.
        • Uncorrected L5 Rotation and Tilt:
          • A significant risk factor for the lack of resolution or even progression of olisthetic scoliosis is when the rotation and tilt of the olisthetic (slipped) L5 vertebra are not corrected during the spondylolisthesis reduction procedure.
          • If the "foundation" (L5) is fixed in an asymmetric position, it can lead to no relief or even progression of the scoliosis.
        • Older Age at Surgery:
          • Older teenagers with olisthetic scoliosis may experience curve progression even after lumbosacral fusion.
        • Larger Preoperative Cobb Angle:
          • A larger Cobb angle of the scoliosis curve before surgery has been identified as a factor related to failed olisthetic scoliosis resolution.
        • Substantial Apical Vertebral Rotation:
          • The presence of noteworthy or substantial apical vertebral rotation in the scoliosis curve has been observed in patients who experience curve progression after lumbosacral fusion.
          • Assessing curve flexibility and apical rotation is crucial for surgical decision-making.
Independent Scoliosis:
Paediatric Idiopathic scoliosis
  • It's important to distinguish olisthetic/spasm scoliosis from "independent" scoliosis (e.g., adolescent idiopathic scoliosis), as the latter may require separate treatment based on its own principles and might not resolve after spondylolisthesis surgery.
  • A key distinguishing factor is that idiopathic scoliosis typically exhibits significant vertebral rotation at the apex, whereas spondylolisthesis-induced scoliosis has no or only mild vertebral rotation.
  • Management
    • Inclusion of the lithesis Vertebra in Fusion:
      • In cases of Meyerding grade IV spondylolisthesis associated with scoliosis the olisthetic vertebra should be included in the vertebral arthrodesis due to the high instability of the area.
      • For lower-grade (I-III) spondylolisthesis that is asymptomatic and associated with scoliosis requiring surgery, the olisthetic level may be excluded from the arthrodesis if it is not part of the primary curve planned for fusion.
        • Studies have shown stability of the olisthetic vertebra and no progression of scoliosis in such cases over several years.