Operative Planning

• Review imaging (magnetic resonance imaging, computed tomography [CT] scan, angiogram)
  
• Review previous operative report (problems encountered, type of closure)
  
• Review previous incision (wound healing difficulties, tenuous areas, free flaps)
  
• Review prior treatments (radiation, chemotherapy)
  
• Plastic surgery consult if wound closure is expected to be difficult

Equipment

• Major cranio to my tray
  
• Mayfield head holder
  
• Neuronavigation (optional)
  
• High-speed drill
  
• Fish hooks (optional)
  
• Intraoperative monitoring

Operating Room Set-up

• Headlight
  
• Loupes
  
• Bipolar and Bovie cautery
  
• Microscope (depending on pathology being addressed)

Anesthetic Issues

Positioning

• Dictated primarily by the pathology being addressed
  
• If plastic surgery will be necessary for closure, ensure site for donor flap (trapezius, etc., is prepped and accessible). Similar consideration should be given to access for abdominal fat, fascia lata, etc., if need for these are anticipated or possible during the case.

Minimal Shave

• Use electric clippers
  
• Expose prior incision with 2-cm strip as well as any extension of prior incision
  
• Slick hair bordering incision down with antibiotic ointment (bacitracin, neomycin)

Sterile Scrub and Prep

Craniotomy

• Depending on the interval between the initial craniotomy and reoperation, the craniotomy can be a simple matter of removing a few screws and lifting off the bone flap or may be very similar to the original operation.
  
  
  
  • Remove fixation implements (plates, screws, wires, suture)
    
  • Define border of prior craniotomy using a periosteal dissector to detach flap from skull. Areas where skull has fused to prior bone flap should be cut with a high-speed drill (large) or Kerrison punch (small).
    
  • Once flap is free at edges, entire flap must be freed from underlying dura prior to removal with a periosteal elevator. Expect dural defects, especially in patients closed with synthetic on-lay grafts. Bone flap/dura/brain may be adherent as a unit so flap should be gently elevated until free to avoid brain injury.
    
  • Generally the dura will be tightly adherent to the margins of the prior craniotomy so epidural tack-up sutures are not necessary.
    
  • If the craniotomy needs to be extended, the dura should be freed from the overlying bone to be removed prior to extending the cuts with a high-speed drill.

Dura Opening

• The dura will be most adherent to the brain at any prior suture lines. For reoperative craniotomies performed at an extended time after the original operation, plan a new dural opening. The original suture line may be used for reoperations done shortly after the original operation.
  
• In cases where an on-lay synthetic dural graft was used, separating the dura from the underlying brain may not be feasible or desirable. In these cases, view the dura as an extension of the cortical surface and incise the synthetic dura and underlying cortex together.

Closure

• Use 4–0 silk suture to close dura. A water tight seal on the dura is critical as healing of superficial tissues may be retarded.
  
• Patch areas where dura does not close with autograft if possible (periosteum or temporalis muscle) and allograft if not possible (pericardium). Synthetic graft materials are available.
  
• Replace bone flap with titanium microplates. Often original plates may be reused safely and successfully.
  
• Close deep muscle tissues with 0 Vicryl sutures
  
• Close galea with inverted 3–0 Vicryl sutures
  
• Scalp may be closed with staples or nylon sutures
  
• A subgaleal drain (1/8-inch Hemovac [Zimmer, Warsaw, IN] and no. 7 Jackson-Pratt) should be left overnight

• Antibiotics for 24 hours for prophylaxis or longer if reoperation done for débridement.
  
• Remove drain at 24 hours postoperative
  
• Remove sutures or staples at 10 to 14 days postoperative