New-Onset Craniosynostosis After Posterior Vault Distraction Osteogenesis

Secondary metopic craniosynostosis after posterior cranial decompression in cloverleaf skull deformity

Cloverleaf skull deformity or Kleeblattschadel syndrome is a severe condition where multiple cranial sutures are absent and prematurely fused, leading to a trilobate head shape. The remaining open sutures or fontanelles compensate for rapid brain expansion, while the constricted fused calvarium restricts brain growth and results in increased intracranial pressure. Recent data show that early posterior cranial and foramen magnum decompression positively affects infants with cloverleaf skulls. However, long-term sequelae are still rarely discussed. We hereby report a child who developed secondary metopic craniosynostosis after posterior cranial decompression, which required a front-orbital advancement and cranial remodelling as a definitive procedure.

Degree of Sagittal Suture Fusion, Cephalic Index, and Head Shape in Nonsyndromic Sagittal Craniosynostosis

BACKGROUND

Sagittal craniosynostosis may present with complete or partial fusion of the sagittal suture, but relationships between degree of sagittal suture fusion and head shape are currently poorly described. The aim of this study was to characterize sagittal suture fusion patterns and determine associations with head shape in a cohort of patients with nonsyndromic sagittal craniosynostosis.

METHODS

Patients with nonsyndromic sagittal craniosynostosis at a tertiary care center with available computed tomography imaging were included in this study. The anterior and posterior distances of sagittal suture patency were measured along 3-dimensional parietal bones. Degree of sagittal suture fusion was compared to head shape characteristics, including cephalic index (CI), frontal bossing, and occipital bulleting.

RESULTS

Ninety patients (69 male) were included in this retrospective study. The sagittal suture was on average 85.6±20.1% fused, and 45 (50.0%) patients demonstrated complete fusion of the sagittal suture. CI was associated with increased degree of fusion for the anterior one-half (ρ=0.26, P=0.033) and anterior one-third (ρ=0.30, P=0.012) of the sagittal suture. Complete fusion of the anterior one-third of the sagittal suture predicted higher CI (β=13.86, SE=6.99, z=-0.25, P=0.047). Total degree of sagittal suture fusion was not predictive of CI or head shape in any analysis.

CONCLUSIONS

Decreased fusion of the anterior one-third of the sagittal suture, but not total suture, may paradoxically predict increased severity of scaphocephaly as quantified by CI in nonsyndromic sagittal craniosynostosis.

Posterior vault distraction osteogenesis: indications and expectations

Cranial vault remodeling (CVR) in patients with craniosynostosis serves to correct abnormal skull morphology and increase intracranial volume to prevent or treat pathologic increases in intracranial pressure (Taylor and Bartlett, Plast Reconstr Surg 140: 82e-93e, 2017). Distraction osteogenesis is a well-established technique for bony repositioning and growth stimulation in the facial and long bones, in which the gradual separation of bony segments at an osteotomy site results in generation of new bone and subsequent bone lengthening (Greene, 2018). While initially described in the orthopedic literature, the relevance and applicability of distraction osteogenesis to craniofacial surgery has been well-studied and is now well-established (Steinbacher et al., Plast Reconstr Surg 127: 792-801, 2011). Posterior cranial vault distraction osteogenesis (PVDO) was introduced as a treatment option for cranial vault expansion in patients with craniosynostosis in 2009 by White et al., based upon the premise that posterior vault distraction could provide greater intracranial volume expansion than fronto-orbital advancement and remodeling (FOAR), but that acute posterior cranial vault expansions were limited by the soft tissue envelope of the infant scalp and prone to relapse related to the supine positioning typical of infants (White et al., Childs Nerv Syst 25: 231-236, 2009). Since this introduction, significant evidence has accrued regarding the safety of, and outcomes after, PVDO. PVDO is now known to provide larger increases in intracranial volume in comparison to anterior cranial vault remodeling procedures (Derderian et al., Plast Reconstr Surg 135:1665-1672, 2015) and to provide morphologic improvements in both the posterior and anterior cranial vaults (Goldstein et al., Plast Reconstr Surg 131:1367-1375, 2013). Perioperative major morbidity is comparable to conventional vault remodeling (Taylor et al., Plast Reconstr Surg 129:674e-680e, 2012) and the procedure has been safely applied to patients of various ages with syndromic and non-syndromic craniosynostosis (Zhang et al., J Craniofac Surg 29:566-571, 2018; Li et al., J Craniofac Surg 27:1165-1169, 2016). Many high-volume craniofacial centers now consider PVDO the preferred first operation in infants with syndromic craniosynostosis, and indications for this procedure continue to expand as evidence accrues regarding its utility and safety (Steinbacher et al., Plast Reconstr Surg 127: 792-801, 2011; Swanson et al., Plast Reconstr Surg 137:829e-841e, 2016).

Secondary Raised Intracranial Pressure After Cranial Vault Remodeling for Isolated Sagittal Craniosynostosis

ABSTRACT

The management of sagittal craniosynostosis has evolved over the decades as teams seek to refine their surgical approaches to idealize head shape with the least possible morbidity. Here, the authors identify the incidence of raised intracranial pressure (ICP) and its risk factors, requiring secondary surgical intervention after cranial vault remodeling (CVR) procedure at a single tertiary referral craniofacial unit. A retrospective case-control study was performed on the patients with isolated non-syndromic sagittal craniosynostosis. All patients who underwent CVR in our unit and had a minimum of 1.5 years follow-up were included. One hundred and eighty-four patients (134 male and 50 female) who underwent primary CVR surgery for isolated sagittal craniosynostosis were included. Thirteen patients (7.07%) had clinical evidence of late raised ICP resulting in repeat CVR procedures. Higher incidence of raised ICP in patients who had primary surgery before 6 months than after or at 6 months of age (P = 0.001). There were 23.5%, 5.6%, 3.2%, and 1.9% of secondary raised ICP patients who underwent the primary surgery between 1999-2004, 2005-2010, 2011-2015 and 2016-2018, respectively (P = 0.024). The risk of secondary raised ICP was higher in patients with isolated sagittal craniosynostosis whose primary surgery occurred before the age of 6 months (two times more likely). More extensive CVR can be performed safely in sagittal synostosis with promising outcomes. The late presentation with raised ICP reinforces the importance of long-term multidisciplinary protocol-based follow-up.

Craniosynostosis: Posterior Cranial Vault Remodeling

Posterior cranial vault distraction osteogenesis is a powerful, reliable, low-morbidity method to achieve intracranial expansion. It is particularly useful in treating turribrachycephaly seen in syndromic craniosynostosis, allowing for gradual expansion of the bone while stretching the soft tissues over several weeks allowing greater volumetric expansion than conventional techniques. Posterior cranial vault distraction osteogenesis constitutes a more gradual remodeling modality, with infrequent complications. As a first step in intracranial expansion, it preserves the frontal cranium for future frontofacial procedures. A drawback is the need for a second surgery to remove the device, and this must be taken into account during counseling.

Comparison of endocranial morphology according to age in one-piece fronto-orbital advancement using a distraction in craniosynostotic plagiocephaly

The capacity for cranial remodelling is known to be better at younger ages. The timing of cranioplasty could affect the axis of the skull base. We investigated whether age at the time of distraction is related to the outcome of endocranial morphology correction. In this retrospective study, we investigated the surgical outcome of 14 patients with unilateral craniosynostotic plagiocephaly who underwent one-piece fronto-orbital advancement without bandeau by using a distraction technique between April 2005 and December 2015. Satisfactory results were achieved in all 14 patients with unilateral coronal suture craniosynostosis. An average distraction of 27.3 mm was obtained without detachment from the dura mater. The endocranial angulation of the anteroposterior axis was reduced from 165.4° to 173.5° on average, and the average total change was 8.1°. Between patients aged <1 year and those >1 year, there was a statistically significant difference in the postoperative endocranial angulation of the anteroposterior axis after 3 months (p = 0.003). The distraction techniques resulted in better correction of endocranial morphology. This indicates that the changes in the skull base axis after one-piece fronto-orbital advancement without bandeau are related to the remodelling capacity of the skull base in growing children based on the dura mater.

Distraction Osteogenesis Versus Conventional Fronto-Orbital Advancement for the Treatment of Unilateral Coronal Synostosis: A Comparison of Perioperative Morbidity and Short-Term Outcomes

Fronto-orbital advancement and remodeling (FOAR) remains the most widely practiced treatment of unicoronal craniosynostosis (UCS) despite recent studies of ocular dysfunction and aesthetic shortcomings in the long-term. The aim of the study was to compare perioperative morbidity and short-term outcomes of a recently developed, nondevascularizing, distraction-based treatment of UCS with conventional FOAR. To do so, the authors compared the first 6 patients who were treated with a new osteotomy/distraction approach to the last 6 patients who underwent traditional FOAR for the treatment of UCS with regards to demographics, operative details, perioperative morbidity, and short-term outcomes.Between July 2012 and June 2014, 6 patients underwent each procedure. Duration of surgery and length of hospital stay in the distraction group were on average 2 hours 7 minutes and 3.4 days, respectively, significantly less than in the traditional FOAR group (P = 0.039, P = 0.032, respectively). Perioperative blood loss averaged 169 mL, which trended toward less than in the traditional group (mean of 400 mL, P = 0.065). Patients undergoing conventional compared with distraction osteogenesis-mediated FOAR were significantly more likely to develop new-onset strabismus postoperatively (odds ratio 15.4; P = 0.0384). All 12 patients completed therapy without complications and with Whitaker grade I results at latest follow-up.In the perioperative period, distraction-mediated cranial vault remodeling provides similar correction of the aesthetic deformity associated with UCS and an improved morbidity profile. Longer follow-up is needed to determine how distraction compares with FOAR with respect to neuropsychologic and long-term aesthetic outcomes.