mastoid and in these patients the skull base and position of the ears is level, all in contrary with plagiocephaly due to craniosynostosis. displacement of one ear to the front is characteristic for deformational plagiocephaly. primary microcephaly primary microcephaly shows a clinical image of craniosynostosis, but due to a different cause. the primary failure is the absence of growth of the brain, rendering the sutures of the cranial vault useless. as a consequence, the sutures close, presenting a pansynostosis like image. a differentiation between these two conditions can be made with a computed tomography (ct) scan. the subarachnoid spaces are typically enlarged with primary microcephaly, whereas they are reduced or absent in true pansynostosis. treatment the primary goal of surgical intervention is to allow normal cranial vault development to occur. this can be achieved by excision of the prematurely fused suture and correction of the associated skull deformities. if the synostosis goes uncorrected, the deformity will progressively worsen not only threatening the aesthetic aspect, but also the functional aspect. this is especially prevalent with asymmetric conditions, such as unilateral coronal synostosis, with compromised function of the eyes and the jaw. in addition, signs of compromised neurodevelopment have been seen amongst all the synostoses, although this may also be caused by primary maldevelopment of the brain and can thus not be prevented by surgical intervention. there are a few basic elements involved in surgical intervention which is aimed at normalization of the cranial vault: surgery for craniosynostosis is often associated with significant perioperative hemorrhage so multiple strategies are often used to minimize blood loss. one such method involves the injection of vasoconstrictive agents (i.e. epinephrine) seven to ten minutes before scalp incision. additionally, the initiation of surgery should be delayed until blood products are physically present in the operating room. another general agreement is the avoidance of the use of titanium plates in the fixation of the skull. one potential complication following this procedure involves the gradual movement of the titanium plates towards the brain, induced by resorption of the innermost bone layer of the skull with deposition of new bone on the outermost layer, thereby integrating the titanium plates. in some cases, the plates have been observed to come into direct contact with the brain. absorbable plates are now used instead. timing of surgery the prevention of post-surgical complications, including those mentioned above, plays an important role in discussions over the timing of potential surgery. the general consensus is to perform surgery in late infancy, i.e. between six and twelve months. within this time frame the efficacy of surgery will be enhanced for several reasons: the bone is still more malleable and can be remodelled relatively 'simply' by greenstick fractures of the bone. at approximately one year of age the bone has become more mineralized and brittle and needs to be attached to the surrounding bone with sutures or an absorbable plate. reshaping of the cranial vault most commonly means excision of the bones to allow shape adjustment. replacement of cranial bones can leave 'gaps' which are readily re-ossified before the age of one year, but will need bony filling thereafter. most surgeons will not intervene until after the age of six months due to the heightened risk which blood loss poses before this age. it is generally preferable to wait until after three months of age when anaesthetic risks will also be decreased. surgery is not performed in early childhood in every country; in some countries surgical intervention can take place in the late teens. it is important that families seek out a pediatric craniofacial physician who has experience with craniosynostosis for proper diagnosis, surgical care, and followup. sagittal craniosynostosis/scaphocephaly there are two surgical procedures which are commonly used to treat sagittal synostosis. the matter of which procedure is superior is still heavily debated amongst the surgeons treating this condition, however it is generally agreed upon that the cephalic index should be used to assess the efficacy of the preferred surgical intervention. firstly, the extended strip craniectomy will be discussed, which is a further developed form of the traditional craniectomy. the traditional procedure involved only the excision of the closed suture, with the intent that the compensatory skull deformations would automatically be corrected by the fast growth of the brain during the first year of life.this did not quite result in a true normalization of the cranial vault, causing the development of numerous modifications. one of those is the extended strip craniectomy. this procedure can be performed by using an endoscope, becoming more popular due to the resultant rapid recovery of the child and reduced need for blood transfusion. the patient is afterwards placed in a custom made molding helmet to correct the resting deformities of the skull. in the other widely used surgical procedure, total cranial vault remodelling, the compensatory deformities are corrected during the operation, with excision of the fused suture. most of the bones that collectively form the cranial vault – i.e. the frontal, the parietal and the occipital bones – are removed and reshaped to normalize the contours. the bones are then replaced and fixated to form a cranial vault with a normalized shape. retrospective analysis has given an indication that the use of total cranial vault remodelling provides children with a better cephalic index than does the extended strip craniectomy. an approach that is currently being evaluated involves the use of springs. this intervention is likely most effective when used in the time frame between three and six months of age. metopic synostosis/trigonocephaly the main elements of metopic suture closure involve a low volume of the anterior cranial fossa, the metopic ridging and hypotelorism. these problems are all addressed during the surgical intervention. the volume is increased by placing the frontal bones and the supraorbital rim further forward. this is done by excision of the bones after which they are reshaped with greenstick fracturing. replacement of the bones provides a possibility for the correction of the hypotelorism at the same time. a bone graft is placed in between the two halves of the supraorbital bars, thereby increasing the width between the orbits. the metopic ridge can then be corrected with a (simple) burring. unilateral coronal synostosis/anterior plagiocephaly the treatment of unilateral coronal synostosis is typically performed in two parts: the forward advancement of the supraorbital bar and the correction of the orbital asymmetry. the supraorbital bar is the rim just above the eye socket; as discussed under phenotype, the supraorbital and the frontal bone are typically recessed at the ipsilateral side of the head. the goal of treatment is to position this bar together with the frontal bone in a plane three millimetres further forwards than the vertical plane of the cornea. a two-dimensional sagittal image is used to pre-operatively determine the extent of movement, which can vary between seven and fifteen millimetres depending on the severity of the deformity. the orbital asymmetry exists typically of a narrower and taller orbit at the ipsilateral side of the head. the contralateral orbit, however, is wider than usual. symmetry is restored by extracting a small piece of bone from the supraorbital bar at the contralateral side, thereby reducing the width. this bone fragment is then introduced into the supraorbital bar on the ipsilateral side, thereby increasing width. the height of the orbit is altered at the ipsilateral side only, by extracting a piece of bone. any correction of the nasal tip, which points towards the contralateral side, will not be performed during childhood. unilateral lambdoid synostosis/posterior plagiocephaly an excision of the flattened occipital bone with release of the fused suture tends to correct the cranial vault deformity. bilateral coronal synostosis/brachycephaly the treatment of bilateral coronal synostosis shows a high degree of overlap with treatment of unilateral coronal synostosis; in both surgical interventions is the forward advancement of the supraorbital rim together with the frontal bones is an important part of the procedure. again, the plane three millimetres further forwards than the vertical plane of the is the appropriate position to place the bone. the increased height of the skull is addressed in the same procedure. parts of the flattened occiput are extracted and given a rounder shape by greenstick fracturing them. pansynostosis/kleeblattschädel the treatment of pansynostosis comprises the expansion of the anterior cranial vault, as well as the posterior cranial vault. whilst this may be accomplished in one procedure it is generally performed in two stages. complications the most common complications of uncorrected craniosynostosis include increased intracranial pressure, asymmetry of the face, and malocclusion. asymmetry of the orbits often leads to strabismus. epidemiology it is estimated that craniosynostosis affects 1 in 1,800 to 3,000 live births worldwide. three out of every four cases affect males. sagittal synostosis is the most common phenotype, representing 40% to 55% of nonsyndromic cases, whilst coronal synostosis represents between 20% and 25% of cases. metopic synostosis is a factor in 5% to 15% of cases, and lambdoid synostosis is seen in 0% to 5% of nonsyndromic cases. five to 15% of the time more than one suture is involved; this is referred to as "complex craniosynostosis" and is typically part of a syndrome.