Bone Graft Expansion in Cranioplasty Using a Split-Bone Technique

Abstract

Decompressive hemicraniectomy (DHC) is performed in emergent cases of uncontrollable intracranial hypertension in which noninvasive procedures or medications are not able to safely maintain pressure within the cranium, increasing the risk of morbidity and mortality. The native bone flap is then replaced, a procedure referred to as cranioplasty, nearly three to six months after injury to allow time for brain relaxation. However, in cases with persistent cerebral edema at the time of cranioplasty, techniques are often applied intraoperatively, including mannitol, external ventricular drain, or lumbar drain placement. To avoid the risks of delaying the procedure or drain placement, we demonstrate a novel technique of splitting the bone flap to adequately increase the size and flexibility. Three patients with a mean age of 44 underwent this novel technique during cranioplasty due to persistent brain edema following a DHC. The new operative technique was successfully performed to compensate for the lingering edema, and all three patients were monitored postoperatively, showing no complications. In this study we demonstrate a new technique to alter bone flap size and flexibility during cranioplasty cases with persistent brain edema, avoiding the need for invasive drain placement. All patients experienced no complications or new cranial/skull defects postoperatively.

Keywords: cerebral edema; craniectomy; cranioplasty; craniotomy; neurocritical care.

Figure 1. (A, B) Coronal and Axial sections before cranioplasty. (C, D) Coronal and Axial section post-operatively.

The arrows point towards the portion of the cranium removed and repaired.

Figure 2. (A, B) Coronal and Axial sections before cranioplasty. (C, D) Coronal and Axial section post-operatively.

The arrows point towards the portion of the cranium removed and repaired.

Figure 3. (A, B) Coronal and Axial sections before cranioplasty shortly after the craniectomy. (C, D) Coronal and Axial section post-operatively.

The arrows point towards the portion of the cranium removed and repaired.

Figure 4. In situ operative viewing of second case. (A) Creating incision along the midline for splitting of the bone flap was done for all three cases. (B) Visualization of extended bone flap before reapproximation. (C) Reapproximated bone flap with graph extension.

The arrows show the portion of the flap adjusted to accommodate excess swelling.

Figure 5. 3-Dimensional representation of the technique to visualize the plates and hinge of the skull flap after placement.