Kyphosis


Kyphosis defined: This drawing depicts the spinal condition of kyphosis. Kyphosis is an abnormal increase in normal kyphotic (posterior) curvature of the thoracic spine which can result in a noticeable round back deformity.

Adult Kyphosis:

Adult Kyphosis includes congenital/developmental causes and traumatic and iatrogenic conditions but overall osteoporosis is the most common cause of sagittal deformity.

Treatment has undergone marked evolution from the historic treatment with body casts to posterior fusion with Harrington instrumentation.

Anterior/Posterior fusion and segmental instrumentation now can produce improved correction.

Normal Sagittal Contour:

Posterior thoracic convexity is normally 20° to 40°

An increase in thoracic kyphosis and a decrease in lumbar lordosis occur with advancing age and are thought to be more pronounced in females

Subjects with greater lumbar lordosis generally had greater thoracic kyphosis and vice versa

Normal lumbar lordosis in children was approximately 18 to 50 and in adults 9° to 57 °

Effects of Aging on Sagittal Contour:

Newborn has a slight posterior convexity from occiput to sacrum. As the infant begins raising its head, a cervical lordosis develops

When walking begins, the pelvis tilts, lumbar lordosis occurs and thoracic kyphosis becomes more pronounced

The thoracic and sacral kyphosis are primary curves because they were present at birth. The cervical and lumbar lordosis are secondary curves

Measurement of Cobb Angle is measured to determine the maximum curve angle. The measurement is from endplates of vertebrae. At the distal ends of the curve.

Postural Kyphosis

Etiology:

  • Poor posture, slouching
  • Most common in adolescents and young adults
  • Developing adolescent females are prone to this disorder. They will slouch and exhibit poor posture to hide their developing breasts.
  • An increase in thoracic kyphosis, generally less than 60°. It is always a flexible curve.
  • Compensatory hyperlordosis of the lumbar spine.
  • The kyphosis corrects when the patient is asked to “stand up tall”

Treatment

  • No evidence that bracing or exercise will change the natural progression of the curvature.
  • Patient education about posture is vital part of treatment.
  • Parent education is also important. Nagging the child does not help.
  • Surgical treatment is rarely indicated.

Scheuermann’s Kyphosis Defined

  • A thoracic kyphosis of more than 40°
  • Three or more adjacent vertebra that are wedged 5°
  • Characterized by schmorl’s nodes, irregular endplates, and a narrowing of verterbral disc space.
  • Increased veterbral anterior/posterior diameter at the apex

Scheuermann’s Kyphosis Demographics:

Demographics:

  • Prevalence varies between 1% and 8%, but only 1% seek treatment
  • Age of onset is unknown
  • Rarely seen before 10 or 11 years of age
  • Cosmetic deformity is the most common complaint
  • About 50% of those who seek medical attention have pain, but more than 78% of patients have pain if lumbar spine is involved.
  • Some patients develop lumbar spondylolysis pars fracture later.

Scheuermann’s Kyphosis Etiology:

Theoretical Etiologys:

  • Scheuermann postulated that the deformity was caused by a vascular necrosis of the vertebral ring apophysis
  • Ippolito and Ponsetti have demonstrated abnormal cartilage matrix with diminished glycoproteins and a different type of collagen in affected vertebral end-plates
  • Endocrinopathy has also been investigated as a possible cause
  • Other authors have suggested stress injuries to the vertebral growth plates and the thoracolumbar and lumbar spine
  • A genetic predisposition to Scheuermann’s disease has been suggested but not proven
  • Collagen weakness and stunted ossification of the vertebral endplate are characteristic.
  • Osteopenia, nutrition and endocrine: these may be causative factors of increased incidence in patients with Turner’s syndrome, nontropical sprue, and cystic fibrosis

Scheuermann’s Kyphosis Clinical Findings:

Clinical Findings:

  • An adult presenting with low back pain or a teenager with poor posture with or without pain
  • Physical examination usually reveals a sharp, rigid kyphosis
  • Kyphosis is increased with flexion and incompletely corrected with extension
  • Lumber hyperlordosis, increased pelvic tilt and associated hamstring tightness
  • Sagittal plumb line should cross C7-T1, T12-L1, and posterior sacrum normally.
  • Normal thoracic kyphosis : 30º-40º, mean = 34º
  • Normal lumbar lordosis : 55º-65º(two-thirds of lordosis at L4-L5 and L5-S1)
  • Lumbar lordosis should be about 30ºgreater than thoracic kyphosis
    30% have associated mild scoliosis.

Scheuermann’s Kyphosis Biomechanics:

Biomechanics:

  • Anterior column fails, resulting in compression, and posterior column fails, resulting in tension.
  • Posterior structures: lamina and ligamentum flavum are relatively stronger than facets, capsules and interspinous ligaments, resisting tension.
  • Growth centers adjacent to the vertebral endplate (not ring apophysis) : anterior cartilaginous columns on axial loading have stunted growth and posterior physis hypertrophy due to tension load.
  • With kyphotic deformity, spinal flexors become stronger then extensor because of moment arm of kyphotic deformity.
  • Deformity increases momentum and further deformity results.
  • Eccentric loading affects cartilaginous growth (compression decreases growth anteriorly and tension increases growth posteriorly, resulting in more kyphosis.

Scheuermann’s Kyphosis Bracing:

Bracing:

  • Brace is used for vertebral wedging greater than 5ºand curves between 45º-65º, in patients with 1 to 2 years of growth remaining.
  • Milwaukee brace for apex above T9
  • TLSO for apex below T9 and thoracolumbar curves
  • Curve correction and wedging improvement of about 40% can be expected after 6 to 12 months. The brace should be weaned with skeletal maturity, but loss of correction is expected after 10 years.
  • The brace may have to be changed every 4-6 months until maximum correction is achieved.
  • Exercise stressing pelvic tilt, abdominal strengthening, spinal flexibility, and extension of the thoracic spine is an important part of the treatment plan.

Scheuermann’s Kyphosis Treatment Options:

Non-Operative Treatment

  • Brace treatment is controversial
  • Although some loss of correction occurred over time, final results showed improvement in 69% of the patients

Operative Treatment

  • Surgical treatment of Scheuermann’s kyphosis is also controversial
  • Combined anterior and posterior
  • Posterior
  • Anterior

Scheuermann’s Kyphosis Differential Diagnosis:

  • Postural round back deformity is characterized by modest kyphosis (40º-60º), is flexible and no radiologic changes
  • Inflammation and infection may include discitis, osteomyelitis, and spondylitis (ankylosing spondylitis, Reiter’s syndrome, psoriasis, and inflammatory bowel disease)
  • Trauma due to multiple compression fractures
  • Tumors may include ABC, osteoid osteoma, osteoblastoma, EG, spinal cord tumors, and syringomyelia.
    Congenital kyphosis (type 2).

Scheuermann’s Kyphosis Indications for Surgery:

  • Severe deformity after growth completion with unrelenting pain (usually >65 º and >10 º wedging and resistant to bracing for 6 months)
  • Neurologic signs or symptoms (rarely reported in literature, maybe related to thoracic disc herniation, epidural cysts, or the hyperkyphosis itself, and tend to occur in adult patients.
  • Pain
  • Progressive deformity
  • Neurologic compromise
  • Cardiopulmonary compromise (kyphosis >100 º)
  • Cosmesis

Scheuermann’s Kyphosis Surgery Considerations:

  • Postoperative regimen: cast or TLSO for 6 to 9 months until solid fusion.
  • Complications include pseudarthrosis and instrument failure (greater in posterior fusion alone), loss of correction, infection, pulmonary complications, and neurologic deficits.
  • Expected post-operative correction is about 50%.

Scheuermann’s Kyphosis Surgical Technique:

  • Posterior long fusion and instrumentation for curves <65º and bending correction to < 50º.
  • Posterior instrumentation should extend the entire kyphotic region, and distally, it should include one lordotic vertebra (usually L1 or L2)
  • Instrumentation should be applied with gradual cantilever bending and segmental compression forces.
  • Multiple posterior osteotomies may improve correction.
  • Anterior fusion (transthoracic approach -open or thoracoscopic technique), followed by posterior fusion and instrumentation for curves > 65º with bending correction to still > 50º.


Goal of Operative Treatment:

  • Posterior long rod multi-segment kyphosis correction
  • +/−anterior release and interbody fusion

Congenital Kyphosis:

Congenital Kyphosis appears in infants where there is a defect in the vertebral formation causing two or more vertebra to fuse together forming a “bar”. This is a progressive disease, and left untreated, pulmonary failure and paralysis are imminent. Early surgical intervention is crucial.

An MRI is performed to check for infringement on the spinal cord. An Anterior/Posterior fusion with a staged anterior release, decompression of the spinal cord, fusion, and strut grafts.

Traumatic Kyphosis:

Traumatic Kyphosis is common from a burst fracture or a compression fracture. The kyphosis may result from the injury or as a surgical complication.