Infection prevention;care of cranial bone for cranioplasty

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Presenters; Grace Mwangi (KRCHN/KRPON) and Pedro Malonza (KRCHN/KRPON)

Introduction;

Craniotomy: A neurosurgical procedure in which a section of the skull is temporarily removed to gain access to the brain for diagnostic or therapeutic purposes. Indicated for traumatic brain injury, brain tumors, aneurysms, and intracranial hemorrhage.

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Craniectomy; A neurosurgical procedure in which a portion of the skull (the bone flap) is removed to relieve pressure on the brain. Unlike a craniotomy, where the bone flap is temporarily removed and then replaced, in a craniectomy the bone is not immediately replaced—it may be stored for later reimplantation (cranioplasty) or discarded if not usable.

• Cranioplasty; A neurosurgical procedure in which a missing portion of the skull is repaired or reconstructed. It is usually performed after a craniectomy, once the brain swelling has subsided.

*Purpose for craniectomy;relieve increased intracranial pressure (ICP) caused by brain swelling or trauma,to give the swollen brain space to expand without being compressed

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• Indications:
• Severe traumatic brain injury
• Stroke with massive brain swelling (malignant MCA infarction)
• Intracranial hemorrhage (bleeding inside the brain)
• Infections or tumors causing swelling

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• 🔹 Intraoperative Care of Cranial Bone Flap
• Aseptic Handling;
• Always handle the bone flap with sterile gloves and instruments.
• Avoid direct contact with non-sterile surfaces.
• Moisture Maintenance:
• Keep the bone moist to prevent drying.
• Wrap in moist sterile gauze soaked in saline or place in a sterile container with normal saline, (just enough to keep it moist) with Vancomycn 2g.

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• Methods: Crypreservation
• Store in sterile container and send to bone bank/freezer (–80°C).
• Limitations;
• While freezing is a good method of preservation,bacteria like staphylococcus aureus can easily grow even under those degrees posing infection during reimplantation.

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Method 2:Bury in abdomen

• The bone flap is usually buried  in a subcutaneous pocket in the abdominal wall.

Why is it done;

Preservation: This in-vivo method preserves the bone flap’s viability and osteogenic ability for reimplantation during the second procedure, cranioplasty.

• Cost-Effective: It is a simple, safe, and cost-effective alternative to synthetic materials, especially in low- and middle-income countries.
• Main reasons against abdominal banking of a bone flap;
• Risk of infection or graft contamination
• Aseptic bone-flap resorption (loss of the bone)-Autologous bone (especially in children) can undergo resorption after reimplantation, causing cranioplasty failure and need for reope
• Not ideal for contaminated/fragmented bone. If the skull was contaminated (open scalp wound)or the flap is comminuted, burying and later replacing that same bone increases infection/resorption risk .
• Logistics and timing. It requires an extra incision, and timing of cranioplasty . Priority is patient’s healing.
• It’s less favored when the bone flap is contaminated, highly fragmented, or when the patient is a child (higher resorption risk).

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Method 3; Autoclaving/microwaving

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• 121 °C for 20–30 minutes (standard gravity displacement cycle)
• 134 °C for 3–5 minutes (pre-vacuum cycle, faster but harsher on bone)
• ⚠️ Caveats:
• High heat denatures bone proteins, kills osteoblasts, and weakens structural integrity.
• Studies show autoclaved bone is more likely to undergo aseptic resorption after reimplantation compared to cryopreserved or abdominally stored bone.

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• Note that cranioplasty is mostly done 6 months after craniectomy during which patients should wear protective helmets till the planned procedure.
• During cranioplasty, bone should be kept moist in sterile saline. Vancomycn powder should be poured after dura closure just before the bone flap is placed to reduce infection.
• Adjuncts of cranioplasty ;
• Bone cement
• Titanium mesh
• PEEK implants

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Peek implant;

THANK YOU

QUESTIONS??