To identify skull-base growth patterns in Crouzon syndrome, we hypothesized premature minor suture fusion restricts occipital bone development, secondarily limiting foramen magnum expansion. Skull-base suture closure degree and cephalometric measurements were retrospectively studied using preoperative computed tomography (CT) scans and multiple linear regression analysis. Evaluation of multi-institutional CT images and 3D reconstructions from Wake Forest’s Craniofacial Imaging Database (WFCID). Sixty preoperative patients with Crouzon syndrome under 12 years-old were selected from WFCID. The control group included 60 age- and sex-matched patients without craniosynostosis or prior craniofacial surgery. None 2D and 3D cephalometric measurements. 3D volumetric evaluation of the basioccipital, exo-occipital, and supraoccipital bones revealed decreased growth in Crouzon syndrome, attributed solely to premature minor suture fusion. Spheno-occipital (β = −398.75; P < .05) and petrous-occipital (β = −727.5; P < .001) suture fusion reduced growth of the basioccipital bone; lambdoid suture (β = −14 723.1; P < .001) and occipitomastoid synchondrosis (β = −16 419.3; P < .001) fusion reduced growth of the supraoccipital bone; and petrous-occipital suture (β = −673.3; P < .001), anterior intraoccipital synchondrosis (β = −368.47; P < .05), and posterior intraoccipital synchondrosis (β = −6261.42; P < .01) fusion reduced growth of the exo-occipital bone. Foramen magnum morphology is restricted in Crouzon syndrome but not directly caused by early suture fusion. Premature minor suture fusion restricts the volume of developing occipital bones providing a plausible mechanism for observed foramen magnum anomalies.

Purpose: Early onset of minor suture fusion in syndromic craniosynostosis is associated with midface dysplasia and is a common indication for craniofacial surgery. However, the potential effects of fusion severity on craniofacial growth patterns are not well understood. This study seeks to describe the impact of minor suture fusion severity on midface morphology in Crouzon syndrome. Methods: Pre-operative computed tomography images (CT) of 63 patients with Crouzon syndrome and 63 normocepahlic controls were included. Degree of suture fusion was assessed for the frontosphenoidal, sphenethmoidal, sphenosquamosal, sphenopetrosal, spheno-occipital synchondrosis, frontoethmoidal, and zygomaticosphenoidal sutures. Each suture was graded on a 5-point scale. The sella (S), nasion (N), A point (A), basion (BA), and anterior nasal spine (ANS) landmarks were used to calculate the SNA angle, BA-ANS length of the lower midface, and N-S length of the upper midface. Multiple linear regressions were used to analyze data. Results: The mean age was 43 months and 44% were female. The control group was significantly older ( P < .01) than the patients with Crouzon syndrome. Advanced fusion of the spheno-occipital synchondrosis in Crouzon syndrome correlates with regression of the BA-ANS length by 0.563 mm per incremental increase in suture fusion ( P < .01). Additionally, the lower midface (BA-ANS) was restricted to a greater degree than the upper midface (N-S) with progressive suture fusion in all patient types with ratios of these rates ranging between 0.602 and 0.89 for the 7 sutures analyzed. Suture fusion severity did not impact the SNA angle in any of the analyses performed. Conclusion: The severity of sheno-occipital synchondrosis fusion in Crouzon syndrome contributes to midface hypoplasia. Similarly, all anterior skull base sutures limited lower midface growth to a greater degree than the upper midface.

Background: Endoscopically assisted craniofacial surgery (EACS) has numerous advantages over traditional, open approaches, such as fronto-orbital advancement in treating nonsyndromic craniosynostosis. However, several articles report high reoperation rates in syndromic patients treated with EACS. This meta-analysis and review examines undesirable outcome rates (UORs), defined as reoperation or Whitaker category III/IV, in syndromic patients undergoing primary EACS compared with procedures that actively expand the cranial vault. Methods: PubMed and Embase were searched in June 2022 to identify all articles reporting primary reoperation or Whitaker outcomes for syndromic patients undergoing cranial vault expanding surgery or suturectomy. A meta-analysis of proportions was performed comparing UORs, and a trim-and-fill adjustment method was used to validate sensitivity and assess publication bias. Results: A total of 721 articles were screened. Five EACS articles (83 patients) and 22 active approach articles (478 patients) met inclusion criteria. Average UORs for EACS and active approaches were 26% (14%–38%) and 20% (13%–28%), respectively (P = 0.18). Reoperation occurred earlier in EACS patients (13.7 months postprimary surgery versus 37.1 months for active approaches, P = 0.003). Relapse presentations and reason for reoperation were also reviewed. Subjectively, EACS UORs were higher in all syndromes except Apert, and Saethre-Chotzen patients had the highest UOR for both approaches. Conclusions: There was no statistically significant increase in UORs among syndromic patients treated with EACS compared with traditional approaches, although EACS patients required revision significantly sooner. Uncertainties regarding the long-term efficacy of EACS in children with syndromic craniosynostosis should be revisited as more data become available.