# Personalized Bone Reconstruction and Regeneration in the Treatment of Craniosomiasis
### Overview of Surgical Approaches and Skull Reconstructive Techniques  
Aims of the surgical treatment of CS are (i) to correct the functional and cosmetic anomalies, (ii) to restore the normal spatial relationships between the skull and the contained cerebral and vascular structures, (iii) to reorient the abnormal vectors of cranial growth, and (iv) to correct the possibly associated alterations in cerebrospinal fluid (CSF) dynamics and venous circulation.  
In syndromic craniosynostosis, timing and choice of the surgical procedure result from the complex interpretation of anatomic and functional anomalies and of their variable inter-reaction in different patients at different stages of the disease. When the cranial vault is taken into consideration, posterior cranial vault expansion is indicated when the posterior fossa is volumetrically reduced up to determine a secondary [PERSON] malformation. Conversely, whenever ocular and respiratory functions are sufficiently preserved, fronto-orbital and maxillary advancement are postponed as close as possible to the end of maxillofacial growth, namely around the seventh year of age [44].  
In simple craniosynostosis, timing of the surgical treatment is more standardized, mainly depending on the age at diagnosis and the type of craniosynostosis. In the case of sagittal craniosynostosis, early surgery may be considered if the diagnosis is made in the first four months of life. Main advantages of early surgery in this subset of children are that correction may be achieved by means of minimally invasive cranial expansion techniques and that the relief on intracranial structures is anticipated with benefit on the early phases of brain development [45].  
In children with craniosynostosis involving the coronal ring and the orbits (i.e., metopic and coronal craniosynostosis), open cranial vault remodeling is the preferred surgical technique. Surgery, in this case, is performed starting from the fifth-sixth month of life, an age warranting a more reliable stabilization of the reconstructed cranial vault, thanks to the higher consistency of the bone. In this context, the introduction of bioabsorbable plates and screws has reduced the complications related to the use of titanium devices to fix the bone structures [46], as discussed in the next paragraph.  
A more recent concept in the surgical treatment of craniosynostosis is represented by distraction osteogenesis (DO): this is a method of generating new bone following a corticotomy or an osteotomy and gradual distraction. The method is based on the tension-stress principle proposed by [PERSON] [47,48]. The gradual bone distraction creates mechanical stimulation which induces biological responses, including differentiation of pluripotential cells, angiogenesis, osteogenesis, and bone mineralization, finally resulting in bone regeneration. DO techniques claim various advantages over the conventional cranial vault remodeling techniques, including a shorter surgical time, less bleeding, and good blood supply to the cranial bone because of limited dissection of the _dura mater_, and safe and large expansion of skull, because of simultaneous soft tissue expansion. It can be accomplished either by means of springs or distractors [49].  
One of the main disadvantages of distraction methods is the difficulty to control the vectors of distraction, with a consequent increased risk of mechanical complications, such as unwarranted less expansion or overexpression an undesirable cosmetic outcome, as  
well as dislodgement of the device [49; 50]. A second relevant drawback of springs and distractors is the need of a second surgery to remove the implanted device.