Neurosurgery notes/Spine/Spinal Degenerative Diseases/Lumbar degenerative disease

Lumbar degenerative disease

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Parent item
Spinal Degenerative Diseases
Sub-item
Discogenic lumbar back pain
Acute low back pain
Facet joint arthropathy
Lumbar canal stenosis
Lumbar disc herniation (LDH)
Foot drop

Lumbar spondylosis

  • ‘Spondylosis’ encompasses a group of pain disorders and clinical syndromes related to degeneration of the motion segment,
  • The cardinal symptom being axial lower back pain.
  • Neurological compromise and radicular pain may coexist.
  • Most patients with lumbar spondylosis describe non-specific back pain.
  • Aetiology
    • pain related to disc or facet degeneration and instability.
      • A small group of patients (10– 15%)
      • Degenerative findings on MRI are common in asymptomatic individuals however disc disease with associated Modic changes and significant facet degeneration is rare in younger patients.
      • Certain clinical pointers may pinpoint specific pain generators and appropriate treatment.

Key concepts

  • Spinal function
    • Spine has 3 principal biomechanical roles
      • Load bearing
        • Forces placed on the intervertebral disc are several times greater than the sum of the weight of body parts and supported objects.
        • Regardless of loading pattern the healthy intervertebral disc and its hydrostatic properties, distributes load equally to the vertebral endplate.
        • As in other diarthrodial joints, abnormal loading results in focal degeneration and pain
      • Mobility
        • Spinal musculature
          • small changes in muscle length produce a large range of movement placing the spine under great stress.
        • The ligamentous spine respects a tension- elongation relationship;
          • with elongation tension increases, stability is associated with spinal tension and stiffness.
        • There has been no conclusive evidence that translation or angular movement beyond the normal range of motion is associated with pain however anecdotally spondylolisthesis demonstrates that segmental instability results in pain.
        • Loss of integrity of supporting structures through the degenerative process frequently results in a mechanical and chemical insult to neural tissue.
          • Examples include disc herniation, lumbar canal stenosis, and spondylolisthesis.
      • Protection of the neural elements.
  • Motion segment
    • The ‘motion segment’ consisting of
      • Vertebrae
      • ‘The three- joint complex’
        • 1x intervertebral disc
        • 2x facet joints.
    • Segmental ligaments include
      • Longitudinal
      • Flaval
      • Interspinous ligaments
    • Segmental muscles
      • Splenius
      • Erector spinae
      • Transversospinal
    • Degeneration of one component will lead to degeneration of the entire segment resulting in pain, deformity, and neural compromise.
    • Panjabi
      • describes the spine as a dynamic neuromuscular system with three subsystems (passive, active and neural with feedback subsystems) in equilibrium.
  • Spinopelvic balance
    • Allows the spine to support the weight of the body with minimal energy expenditure.
    • Imbalance
      • results in
        • Muscular fatigue
        • Deformity
        • Pain
        • Psychosocial implications of kyphosis
        • Deficient horizontal gaze
      • Causes
        • ‘failed’ and ‘flat back’ syndrome
    • Assess
      • Full length standing AP and lateral X- rays
        • Allow measurement of spinopelvic geometry
        • Magnitude of sagittal imbalance
        • Degree of correction required to restore balance
  • Number
    • 80% of people experience an episode of low back pain in their lifetime,
      • with 10% developing chronic pain.
    • UK 8.3 million working days are lost per year secondary to musculoskeletal problems;
    • patients are unlikely to return to work after two years of sick leave.
  • Natural history of lumbar back pain
    • benign and in the majority, pain will resolve in 2– 4 weeks
      • >90% are pain- free at 12 months
  • Aetiology
    • Occupational repetitive loading.
    • factors such as age, male gender, and smoking have been implicated.
    • Genetic factors
      • Familial degenerative disc disease is recognized
        • candidate- gene polymorphisms include those encoding collagen, Sox9, the vitamin D receptor metalloprotease- 3, and interleukin- 1.
  • Degenerative cascade
    • The degenerative process has 3 distinct phases.
      • Firstly Minor trauma or repetitive strain → segmental muscle fatigue, spasm, and inflammation → results in axial back pain
        • Disc degeneration manifests as
          • Circumferential annular tears
          • Nuclear matrix changes
        • Facet synovitis and cartilaginous degeneration occurs.
      • Secondly instability characterised by internal disc disruption and resorption, facet capsule laxity, and subluxation.
      • Thirdly stabilisation characterised by osteophytosis and ankylosis reducing motion, thickening of the yellow ligament and circumferential encroachment with compromise of the neural elements.
    • Atul Goel (vertical instability theory)
      • Upright posture against gravity/loss of center of gravity while we walk, stand and sit → human spine accumulate stress + constant mechanical strain → disuse or misuse of spinal muscles → micro listhesis of superior facet over the inferior facet (radiological hard to detect/interfacet articular space reduces due to facet override/this is the Nodal pointy of pathogenesis of degenerative spinal spondylosis) → reduction in vertical height
        • Disc space reduction
          • Circumferential annular tears → disc protrusion
          • Nuclear matrix changes
        • Ligamentum flavum and PLL buckling occurs
        • The perifacetal ligaments and articular cartilage separate from the bone → osteophytes formation
          • The degenerative osteophytes may over grow and form stable fusion between vertebral bodies in an attempt to maintain stability and at times successful
      • Protrusion of disc + ligamentum buckling + osteophyte formation → canal compromise → neuronal compression → neurological deficits
  • Instability
    • ‘Instability’ remains an enigmatic concept;
      • it is the most controversial of the pain syndromes given the normal range of lumbar movement and abnormal movement observed in asymptomatic individuals.
    • It is more likely that abnormal movement → abnormal loading of the annulus and vertebral endplate (pain generators) → increasing demands on the spinal musculature and tendinous attachments → fatigue, and pain.
    • Clinical features
      • The back ‘giving way’
      • Pain increased with sudden trivial movement
      • Back ‘locking’ and ‘catching’ on movement with associated muscle spasm
    • Imaging
      • Anecdotal reports exist of lumbar back pain associated with instability demonstrated by abnormal translation and angulation on dynamic X- rays.
    • Management
      • Focused on improving core strength.
      • Dynamic stabilization devices have been shown to alter the loading pattern which may explain their equivalent efficacy with fusion in the short term.

Risk factors in lumbar degenerative surgery outcome

  • Obesity
    • Varshneya 2021
        • ㅤ
        Obese
        Non obese
        Post op complication
        Esp: Pulmonary, infection, wound, AKI and haematoma
        10.4%
        8.3%
        Lengths of stay
        2.7 days
        2.4
        Reoperation rates at 2 years
        5.8%
        4.7%
        Readmission rate 30 days
        6.3%
        4.4%