Operative Planning

• Patient counseling regarding surgical risks
  
  
  
  
  • Magnetic resonance imagine (MRI)
    
  • Computed tomography myelogram if MRI is inconclusive
    
  • Flexion/extension x-rays if joint instability present
    
  • Postoperative pain
    
  • Potential joint instability
    
  • Cranial nerve deficits
    
  • Cerebrospinal f luid leak
    
  • Posterior fossa syndrome (if intradural)

Equipment

• Basic tray
  
• Suboccipital tray
  
• High-speed drill (Midas Rex with M-35 and B-1 bits)
  
• Adson cerebellar retractors
  
• Intraoperative x-ray/fluoroscopy

Operating Room Set-up

• Headlight
  
• Loupes
  
• Microscope (optional)
  
• Bipolar and Bovie cautery
  
• Intraoperative x-ray
  
• Mayfield head holder

• Assess patient’s pulmonary function for ability to tolerate prone position
  
• Prophylactic intravenous antibiotics (cefazolin 2 g for adults) 30 minutes prior to incision. Consider vancomycin if instrumentation is planned.
  
• Foley catheter for prolonged surgery
  
• Consider electrophysiologic monitoring (e.g., somatosensory evoked potentials)

Positioning

• Prone position with appropriate padding to prevent pressure neuropathies
  
• Arms tucked at sides
  
• Mayfield head holder or tongs with traction to secure head in capital flexion
  
• Mild reverse Trendelenburg position to improve venous drainage
  
• Mayo stand above head

Planning of Minimal Shave

• Use disposable clippers

Planning of Sterile Scrub

• Betadine detergent scrub with sterile gloves
  
• Sterile towel to dry
  
• Incision is marked

Exposure

• Midline skin incision from the inion to the second or third cervical vertebrae
  
• Subperiosteal dissection continued in the midline until the occiput and spinous processes of C2 are exposed
  
• Foramen magnum and C1 cleared of muscular attachments using periosteal elevators and curettes
  
• Bipolar cauterization to control bleeding from paravertebral venous complex
  
• Self retaining retractor is placed