The management of craniosynostosis in Australia and New Zealand

Introduction: The management of syndromic and non-syndromic craniosynostosis is controversial with different units performing various procedures at different points in time and for different reasons. This study was performed to compare protocols of assessment and surgery in craniofacial units in Australasia. Methods: All paediatric craniofacial surgery centres in Australia and New Zealand were surveyed with respect to their current protocols for the preoperative assessment, intraoperative management and postoperative follow-up of syndromic and nonsyndromic craniosynostosis patients. Results: All eight centres completed the survey with 100 per cent response rate. There was considerable homogeneity in the management of the various synostoses. Differences in management were notable in the preoperative assessments that were offered and the management of midface retrusion in syndromic craniosynostoses. Conclusion: Single-suture management among surveyed centres was relatively homogenous. Developmental assessment is not routinely performed for single-suture disease but is desired by the majority of surveyed centres. Postoperative CT scans are not commonly used but a number of centres desired routine use of 3D photometry for outcome assessment. In multi-suture cases, expansion of the posterior vault was performed in all cases but management of midface retrusion was variable.


Introduction
Craniosynostosis involves the premature fusion of one or more cranial sutures.2][3] Synostosis can be 'simple', involving only one cranial suture or 'complex', involving multiple sutures and/or being related to a genetic syndrome with other limb, neurological, respiratory or cardiac abnormalities.The incidence of craniosynostosis in the population is one in 2000-4000 live births with single-suture involvement by far the most prevalent. 4,58][9][10] There are few high-level evidence studies that compare the different management options for craniosynostoses to support a single model of treatment.2][13][14][15][16] Some studies advocate for early surgical correction of synostosis to improve longterm neurocognitive outcomes whereas other centres perform surgery at a later stage.Moreover, some units propose major surgical procedures such as total calvarial remodeling (TCVR) whereas other units treat similar conditions with minimally invasive techniques, with or without adjuncts, such as cranial springs or helmets. 11,17,18[21][22][23][24] The aim of this study was to survey paediatric craniomaxillofacial centres in Australia and New Zealand to document current practices with respect to preoperative assessment, surgical management and postoperative follow-up for patients with both syndromic and non-syndromic craniosynostosis.

Methods
Institutional review board approval from Sydney University was obtained (project number

All eight centres of craniofacial surgery in
Australia and New Zealand who are members of the Australian and New Zealand Society of Craniomaxillofacial Surgeons completed the survey (100% participation).

Preoperative assessment
One centre stated no preoperative investigations were routinely performed, instead being decided on a case-by-case basis.Head circumference was the most uniformly performed preoperative assessment with seven of eight centres using

Bicoronal synostosis management
Bicoronal synostosis was managed with a single procedure in six centres, while the remaining two centres used a two-stage surgical approach.

Genetic testing 3 (1)
CT scan 6 (0) Of those performing a single procedure, timing of surgery was between six-12 months.FOAR was most common, used in five centres.The remaining centre performed SMC.For the two centres who perform two-stage procedure, a posterior vault distraction was performed at six months of age followed by FOAR thereafter at 12 months of age.

Follow-up for single-suture craniosynostosis
All centres followed patients annually or biannually one year postoperatively.There was some heterogeneity in the length of follow-up with three centres reviewing patients until skeletal maturity, two until teenage years, one until ten years of age, one for five years of age and one centre reviewing patients indefinitely.Table 3 shows common investigations performed at follow-up for singlesuture craniosynostosis.

Preoperative assessment
The mean preoperative investigations offered per centre for multi-suture craniosynostosis was greater than the mean investigations for simple synostosis (7.50 vs. 4.13, p=0.003).Head circumference and CT scan are routinely performed preoperatively in all multi-suture/syndromic craniosynostosis patients across all eight centres.
Three dimensional photography is routinely offered at four centres with three of the remaining four stating they wish to offer this in the future.

Management of syndromic craniosynostosis without midface retrusion
In all eight centres, volume expansion of the posterior vault was performed initially.Five centres performed posterior vault distractions, two performed spring-mediated posterior vault cranioplasty and one performed formal posterior vault remodelling.All centres followed expansion of the posterior vault with FOAR with one centre additionally performing tarsorrhaphy.Table 5 summarises the management of multi-suture craniosynostosis syndromic without midface retrusion across eight centres.

Management of syndromic craniosynostosis with midface retrusion
Management of syndromic craniosynostosis with midface retrusion is summarised in Table 6.All  each and FOAR in the remaining two centres.
Table 7 shows common follow-up investigations multi-suture craniosynostosis.

Discussion
Craniosynostosis may present as simple, singlesuture disease, involve multiple sutures or be secondary to complex genetic syndromes where multiple sutures and organs are affected.Craniofacial clinics are necessarily multidisciplinary as the management of these Neuropsychology or developmental assessments of patients with synostosis is not routine.
1][42][43][44] Across Australasia, developmental assessments were offered at two centres for simple, and six centres for multi-suture/syndromic synostosis respectively.For the preoperative assessment of simple synostosis, developmental assessment was the most desired service not currently offered.
The management options for sagittal synostosis, the most common type of single-suture craniosynostosis, remain broad.Sagittal synostosis was originally treated with simple excision of the fused suture (a sagittal 'strip') however, results were inconsistent and the procedure fell out of favour.Some units prefer traditional total calvarial vault remodelling procedures involving the removal of most of the calvarial vault, reshaping and replacing it in order to correct the scaphocephalic head shape. 45Total calvarial vault remodelling is a major surgical undertaking that may involve significant blood loss, long operating time and associated increased hospital length of stay. 46Spring-mediated cranioplasty is a popular alternative to TCVR and, in this study, was used by the most centres for the management of sagittal synostosis.Spring-mediated cranioplasty is usually conducted in patients less than six-seven months of age with an advantage being that it is minimally invasive and provides active expansion of the cranial vault. 47However, once springs are placed, expansion of the vault cannot be controlled and a second procedure is required to remove the springs.No units in Australasia were using endoscopic suturectomy and helmet therapy to treat craniosynostosis, although this technique is practiced elsewhere. 18,48r other synostoses, our study demonstrated that the vast majority of surveyed centres used FOAR for metopic and unicoronal craniosynostosis and PCVR for the rarer lambdoid synostosis.With fusion of the metopic suture, the sagittal and lambdoid sutures compensate producing increased skull width posteriorly and a narrowed forehead and creating a characteristic triangular appearance when viewed from above. 49In some centres, the management of metopic synostosis is dictated by the severity of disease with mildly affected patients undergoing burring of the affected metopic ridge while more severe cases undergo remodeling. 50 unicoronal synostosis, the ipsilateral forehead flattens, the supraorbital rim is elevated and the contralateral forehead undergoes compensatory bossing. 49Fronto-orbital advancement remodelling is the current standard of care for unilateral coronal synostosis. 51mbdoid synostosis is rare with the characteristic deformity being an ipsilateral, flat posterior skull with ipsilateral loss of skull height and compensatory parietal bone bossing.3][54][55][56][57][58][59] Some centres however, advocate for minimally invasive strip craniectomy. 18e approach to patients with syndromic multisuture craniosynostosis was relatively consistent between the surveyed centres.Multi-suture syndromic synostosis without midface retrusion was uniformly managed with an initial procedure to increase the volume of the posterior vault, followed by FOAR.Expansion of the posterior vault is considered the ideal first stage procedure in syndromic multi-suture synostoses as it significantly increases intracranial volume and thus reduces the incidence of raised intracranial hypertension and its sequelae. 60An additional advantage of commencing with posterior expansion is that the fronto-orbital region remains untouched, facilitating future monobloc or Le Fort III advancements as appropriate to the case. 61er 150 syndromes associated with craniosynostosis have been described. 49,624][65] The sequelae of the midfacial hypoplasia of syndromic craniosynostosis may include exophthalmos, obstructive sleep apnoea (OSA) and class III malocclusion.[68] The deformity of midfacial hypoplasia in the setting of syndromic craniosynostosis can be addressed in two ways.The first, a two-stage procedure with early fronto-orbital advancement to address brachycephaly and a later Le Fort III advancement to address the midfacial hypoplasia.
Alternatively, the forehead and midface can be advanced simultaneously as a 'monobloc' or single piece, combining the Le Fort III osteotomy with a frontal bone advancement in patients with severe exophthalmos. 49,63,69,70A perceived advantage of monobloc distraction over Le Fort III is the increased average midface advancement achieved. 69Previous studies have demonstrated improvements in respiratory function, exophthalmos and facial profile with an average of 25 mm advancement, while the average advancement achieved with Le Fort III osteotomies is reportedly in the range of 6-17 mm. 66,69,71,72In the published literature, orbital deficiency (how shallow the syndromic craniosynostosis patient's hypoplastic orbit lies with resultant exophthalmos) approaches 24 mm. 66,69,71,72While Le Fort III has been successful in expanding orbital cavity volume, monobloc osteotomy may provide an alternative for severe exophthalmos. 66e use of distraction techniques in either Le Fort III or monobloc advancements limits the retrofrontal dead space, allows for brain expansion anteriorly and slow soft tissue accommodation and thus reduces complication rates. 61,73Prior to distraction osteogenesis, midface advancement was performed as a single-stage procedure and was associated with increased rates of haematoma, ascending meningitis and frontal bone loss. 62,74e advent of internal/external distraction allows midface advancement to occur in smaller increments over time and hence may improve the safety of procedure. 74,75Distraction is generally well tolerated, supports newly forming bone and avoids the need for bone grafting. 63However, long term data pertaining to changes in rates of secondary procedures post distraction osteogenesis is lacking and currently, despite best efforts, a large proportion of children with midface hypoplasia will require subsequent operations as they reach adolescence and young adulthood. 76Thus far, it seems morbidity and mortality between patients undergoing Le Fort III or monobloc advancements is similar. 69ere are several limitations of this study.Responses

Conclusion
This study represents the first attempt to summarise the management of craniosynostosis across a regional program.Despite significant variability in treatment options, the management of synostoses was relatively similar between centres.It is hoped that this work may stimulate collaborative and comparative research between the different units in Australasia.
2017/354) to conduct a survey of the assessment and management of craniosynostosis.All members of the Australian and New Zealand Society of Craniomaxillofacial Surgeons (ANZSCMFS) were asked about their usual protocols for the preoperative assessment, intraoperative management and postoperative follow-up of patients with syndromic and non-syndromic craniosynostosis.Specifically, the survey noted which craniofacial multi-disciplinary team members assessed the patients preoperatively, what investigations were performed, the choice and timing of surgical procedures for the different patterns of craniosynostosis and finally, the nature and frequency of follow-up.Surgeons were also surveyed as to what assessments they currently do not perform but would like to in the future.Where there was unclear or missing information provided, surgeons were contacted directly by email to clarify their responses to the survey.Data was collated, de-identified and statistical analysis performed using IBM ® SPSS ® Version 25 (SPSS Statistics for Windows, IBM Corp, Armonk, New York, USA, 2017).
eight centres performed an initial procedure to increase the volume of the posterior vault.Five centres performed posterior vault distraction, three performed spring-mediated posterior vault cranioplasy and one performed formal posterior vault remodelling.Subsequent procedures were Le Fort III and monobloc osteotomy in three centres may reflect the ideal but not actual management of craniosynostosis at various centres.Moreover, this survey does not account for individual variations in treatment protocols resulting from atypical presentations or individual surgeon preference.For the most desired preoperative investigations, ambiguity exists as to whether or not providing a service represents a limited resource or if centres did not think it indicated.Lastly, this survey is a snapshot into the practices of craniomaxillofacial centres across Australia and New Zealand at this time with trends in patient management not well represented.Future surveys conducted into the management of craniofacial pathologies should include questions on changing or evolving surgical practice as well as rationale for specific investigations and procedures.

is summarised in Table 2. Sagittal synostosis management
between six and 12 months of age.One centre stated they occasionally performed TCVR in lieu of FOAR in the same age group.