Neurosurgery notes/Procedures/TL spine procedures/Deformity techniques/Osteotomy/SRS-Schwab osteotomy classification/Grade 5 osteotomy/SUK three column vertebral osteotomy

SUK three column vertebral osteotomy

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Grade 5 osteotomy

Fusion Strategy

  • Adult scoliosis:
    • One level above and below end vertebrae
  • Congenital kyphoscoliosis:
    • All vertebrae in index curve
  • Postinfectious kyphosis:
    • Three above to two below resection

Positioning & Monitoring

  • Prone position on Jackson table
  • General anesthesia with IV neuroleptics
  • Continuous SSEP monitoring

Surgical Steps

Incision & Exposure

  • Posterior midline or curvilinear incision
  • Subperiosteal dissection to transverse process tips
  • The dissection was then carried out laterally, exposing the ribs corresponding to the level of the vertebral column resection.

Facetectomy

  • Destroy facets at fusion levels
  • Remove articular cartilage
  • For the ankylosed or fused posterior facet joints
    • No attempt was made to mobilised the joints at this stage.

Pedicle Screw Fixation

  • Use K-wires with radiograph control
    • Putting the pedicle screws before the resection procedure had three functions:
      • To provide reliable intraoperative stability to the vertebral column while the destabilization took place
      • To offer a grip for the vertebral column for the manipulative correction of the deformity; and
      • To provide a radiograph traceable marker for determining the position and the orientation of the vertebral resection.
  • Minimum 4 fixation points on each side of the vertebral resection should be secured before any attempt at vertebral resection
  • Place a temporary rod that is in the shape of the deformity to hole the spine in place.
  • Scoliosis:
    • Initial rod placed on concave side as it is easier to start the vertebral resection from the convex side

Vertebral Column Resection

  • Resection Location
    • Performed at apex of deformity for maximum effectiveness
    • Number of vertebrae removed depends on deformity type and correction needed
    • Adult scoliosis
      • One vertebra resection corrects ~40° in adult scoliosis
    • Congenital kyphoscoliosis group:
      • All the offending anomalous vertebrae were resected.
    • Postinfectious kyphosis group:
      • All the fused vertebrae were resected.
  • Remove posterior elements first
  • Perform total laminectomy and foraminal unroofing
  • The transverse process and the corresponding rib on the working side of the vertebral column (opposite the side with the temporary rod) were removed to expose the lateral wall of the pedicle.
  • Meticulous subperiosteal dissection was deepened following the lateral wall of the vertebral body until the anterior surface of the vertebral body was comfortably palpable.
  • Under visual control, the pedicles and the lateral portion of the vertebral body were removed by using a small osteotome.
  • In the thoracic spine, the rib heads were removed at this stage to allow complete resection of the lateral wall of the vertebral body and to allow untethered motion of the vertebral column
  • Remove vertebral body and disc piecemeal
  • Preserve a thin shell of bony posterior vertebral wall beneath the dural tube.
  • The anterior walls were also removed in a piecemeal fashion, taking care to leave the soft tissue tube anterior to the vertebral bodies intact.
  • Remove as much vertebral body and disc as possible at this stage, even across the midline, as it was safe to work with the posterior wall protecting the neural elements.
  • When an adequate amount of vertebral body was removed, all of the posterior vertebral wall that was visible lateral to the dural tube was removed with an Epstein reverse-cutting curette and pituitary forceps.
  • Following the resection of the posterior wall on the working side, another temporary rod, contoured to the shape of the deformity, was inserted to the working side and was securely locked to the screws.
  • Then the rod on the other side was removed to allow resection on that side. The same procedure was carried out on the opposite side.
  • Nerve root
    • The thoracic nerve root on the working side was cut to facilitate resection of the body and reconstruction of the anterior column, but the opposite-side nerve root was saved.
    • In lumbar vertebrae, the nerve roots on both sides were kept intact.
  • At the completion of the resection, the rod that had been removed was replaced and connected to the screws on both sides.
  • Final check that the canal was clear of any residual compression at the resection margins and redundant bony or disc tissue attached to the anterior side of the dura that might hinder free, untethered movement of the dural tube

Deformity Correction

  • Two methods
    • Use in situ rod bending OR
    • by exchanging the temporary rods with those precontoured to the desired (corrected) shape one by one, and extension of the operating table was unnecessary.
  • The precontoured rod was advantageous in reducing the operative time and the screw failures from force concentration of a specific screw.
  • The compression and shortening over the resected gap was carried out until the exposed cord looked redundant.
    • Aim: To avoid inadvertent distraction of the neural elements
    • In the adult scoliosis or kyphoscoliosis groups, the compression and shortening over the resected gap could be asymmetrical even with more compression and shortening of the convex side.
    • The compression and shortening over the resected gap was carried out until the exposed cord looked redundant
    • After compression and shortening of the resected gap, the temporary rods were changed to precontoured final rods one by one to avoid any loss of shortening of the resected gap.
  • In the adult scoliosis group, the curve was corrected by
    • Derotation method
    • Cantilever method.
  • In the kyphoscoliosis and postinfectious kyphosis groups,
    • the deformity could be corrected further by in situ rod bending and segmental compression.
  • Perform asymmetric compression if needed

Arthrodesis

  • At the resection gap
    • Perform anterior or circumferential fusion
    • For anterior fusion
      • Use autogenous bone or titanium mesh based on gap size
        • Titanium mesh was more convenient than autogenous tricortical strut to readjust the size of the interbody graft several times.
      • Height of the anterior interbody gap was measured.
        • Shortest height < 5 mm, autogenous cancellous chip bone was placed into the anterior gap.
        • Height > 5 mm, titanium mesh filled with bone chip was inserted into the anterior gap, and autogenous iliac chip bone was placed around the titanium mesh.
      • In the case of the mesh insertion, the mesh was just fit for the anterior gap, and it did not result in lengthening of the anterior column.
      • The mesh cage was inserted from the posterolateral side, through the space between the nerve roots, to fit on the proximal and distal bone bases.
        • The additional compression over the cage was carried out to lock it into place.
    • Unilateral posterior bridging bone graft over the resection gap in the thoracic level
      • Done for circumferential fusion
      • Cons
        • Risk of postoperative hematoma formation by hindering the evacuation of the blood that accumulates in the canal following the surgery
  • All other instrumented level
    • Posterior fusion
  • Insert mesh through posterolateral approach

Closure

  • Place 3-4 closed suction drains at resection site
  • Close wound in layers

Post op

  • The patients were allowed to sit up in bed for 24 hours after the surgery.
  • Patients were allowed out of bed with a body jacket cast at the second postoperative week.
  • The body jacket was kept for 3–4 months
  • Followed by a custom-made plastic thoracic lumbar sacral orthosis for an additional 3 months.