There is an increasing body of evidence in the recent literature, which demonstrates that cranioplasty may also accelerate and improve neurological recovery. Although the exact pathophysiological mechanisms for this improvement remain essentially unknown, there are a rapidly growing number of neurosurgeons adopting this concept.

Communicating hydrocephalus is an almost universal finding in patients after hemicraniectomy. Delayed time to cranioplasty is linked with the development of persistent hydrocephalus, necessitating permanent CSF diversion in some patients.

Waziri et al., propose that early cranioplasty, when possible, may restore normal intracranial pressuredynamics and prevent the need for permanent CSF diversion in patients after hemicraniectomy ¹⁾.

One modifiable factor that may alter the risk of cranioplasty is the timing of cranioplasty after craniectomy. Case series suggest that early cranioplasty is associated with higher rates of infection while delaying cranioplasty may be associated with higher rates of bone resorption.

When considering ideal timing for cranioplasty, predominant issues include residual brain edema, brain retraction into the cranial vault, risk of infection, and development of delayed post-traumatic hydrocephalus.

Waiting to perform cranioplasty is important to prevent the development of devitalized autograft or allograft infections.

It is generally accepted to wait 3 to 6 months before reconstructive surgery. If there is an infected area, this waiting period can be as long as one year.

Cranioplasty is performed after craniectomy when intracranial pressure is under control for functional and aesthetic restorations and for protection, but it may also lead to some neurological improvement after the bone flap placement ^{2) 3) 4)}.

The optimal timing of cranioplasty after decompressive craniectomy for trauma is unknown.

After decompressive craniectomy for trauma, early (<12 weeks) cranioplasty does not alter the incidence of complication rates. In patients <18 years of age, early (<12 weeks) cranioplasty increases the risk of bone resorption. Delaying cranioplasty (≥12 weeks) results in longer operative times and may increase costs ⁵⁾.

Patients with malignant middle cerebral artery infarction frequently develop hydrocephalus after decompressive hemicraniectomy. Hydrocephalus itself and known shunt related complications after ventriculoperitoneal shunt implantation may negatively impact patients outcome.

A later time point of cranioplasty might lead to a lower incidence of required shunting procedures in general ⁶⁾.