Transpedicular Approach

122 Transpedicular ApproachMichael G. Kaiser

Indications

  • Posterior and limited posterolateral exposure of the thoracic spine and canal
    • Resection of lateral and anterolateral thoracic herniated disc
    • Resection/biopsy of tumor or infection involving thoracic pedicle or posterolateral vertebral body
    • Retropulsed bone fragments invading the spinal canal

♦ Preoperative

Operative Planning

  • Patient counseling regarding risk, benefits, and postoperative course
  • Appropriate imaging
    • Plain x-rays
      • Determine number of ribs for localization
      • Assess deformity and/or instability
    • Magnetic resonance imaging (MRI)
      • Determine extent of neural element compression
    • Computed tomography (CT)
      • Evaluate bony anatomy
    • CT/myelogram
      • If MRI contraindicated

Routine Equipment

  • Basic spine tray including Kerrison rongeurs (2 to 4 mm)
  • Cautery: monopolar and bipolar
  • High-speed drill (e.g., Midas Rex)
  • Headlight and loupe magnification

Special Equipment

  • Cell saver: if significant blood loss anticipated in the absence of infection/neoplastic disease
  • Microscope: for intradural pathology

Operating Room Set-up

  • Prone table: Jackson table with Wilson frame or bolsters
  • Mayfield head holder versus Gardner Wells tongs with traction
  • Intraoperative anteroposterior and lateral x-ray versus fluoroscopy

Anesthetic Considerations

  • Secure endotracheal tube for prone position
  • Appropriate blood pressure monitoring
  • Foley catheter for extended cases (beyond 3 hours)
  • Perioperative antibiotics 30 minutes prior to skin incision
  • Perioperative steroids for decompressive or intradural pathology
  • Avoid any orbital compression if patient’s face placed on cushioned mask

♦ Intraoperative

Positioning

  • Prone position
    • Arms tucked along side for pathology rostral to T6–T7
      • Head secured with Mayfield head holder or Gardner Wells tongs and 15 lb of traction
    • Arms placed on cushioned boards for pathology caudal to T6–T7
  • Maintain exposure of posterior iliac crest if fusion intended
  • Ensure that patient is well secured to the operative table in case rotation of the table is desired to enhance ventral visualization.

Sterile Prep

  • Shave with disposable razor
  • Standard scrub and prep

Incision Localization

  • Anteroposterior x-ray used to localize spinal level
    • Requires preoperative verification of rib number

Exposure

  • Midline incision
  • Subperiosteal dissection of paraspinal muscles off spinous processes and lamina to the lateral extent of transverse process
  • Verify level with intraoperative x-ray
  • Placement of self retaining retractors (e.g., Weitlaner or Adson-Beckman)
  • Clear intralaminar soft tissue with curettes/rongeurs

Bone Removal (Fig. 122.1A)

  • Direct entry into the pedicle is achieved by carefully decorticating the junction of the pars and superior facet with a high-speed drill.
    • The pedicle entry site is identified by the blush of cancellous bone.
  • The pedicle can also be located through a laminectomy or laminotomy.
    • The lateral aspect of the ligamentum flavum is resected to reveal the lateral surface of the thecal sac and exiting nerve root.
    • Resection of the surrounding superior facet and pars with Kerrison rongeurs allows identification of the remaining cortical surfaces of the pedicle.
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Jul 11, 2016 | Posted by in NEUROSURGERY | Comments Off on Transpedicular Approach

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