Turkish Journal of Plastic Surgery

: 2021  |  Volume : 29  |  Issue : 1  |  Page : 55--58

Clinical and radiological features of some rare forms of craniosynostosis in clinical practice

Tufan Hicdonmez1, Gaye Filinte2,  
1 Department of Neurosurgery, University of Health Sciences, Dr. Lütfi Kirdar Training and Research Hospital, Cevizli, Kartal, Istanbul, Turkey
2 Department of Plastic Reconstructive and Aesthetic Surgery, Cevizli, Kartal, Istanbul, Turkey

Correspondence Address:
Dr. Tufan Hicdonmez
Department of Neurosurgery, University of Health Sciences, Dr. Lütfi Kirdar Training and Research Hospital, Cevizli, Kartal, 34890


There are rare forms of craniosynostosis with single or multiple suture involvement. These are sphenofrontal plagiocephaly; posterior plagiocephaly with unilateral lambdoid synostosis; combined sagittal and metopic synostosis; combined sagittal and unilateral coronal synostosis; and bilateral lambdoid and sagittal synostosis with Mercedes–Benz pattern. In our study, we aimed to present both clinical and three-dimensional computed tomographic characteristics of these rare forms of craniosynostosis.

How to cite this article:
Hicdonmez T, Filinte G. Clinical and radiological features of some rare forms of craniosynostosis in clinical practice.Turk J Plast Surg 2021;29:55-58

How to cite this URL:
Hicdonmez T, Filinte G. Clinical and radiological features of some rare forms of craniosynostosis in clinical practice. Turk J Plast Surg [serial online] 2021 [cited 2023 Jan 31 ];29:55-58
Available from: http://www.turkjplastsurg.org/text.asp?2021/29/1/55/305907

Full Text


Craniosynostosis is a clinical condition characterized by the premature closure of one or more cranial sutures. This study presents the clinical and three-dimensional computed tomographic (3D-CT) characteristics of some rare craniosynostosis cases diagnosed at the Department of Pediatric Neurosurgery at İstanbul Kartal Dr. Lütfi Kırdar City Hospital. These rare cases are (1) sphenofrontal plagiocephaly, (2) posterior plagiocephaly with unilateral lambdoid synostosis, (3) combined sagittal and metopic synostosis, (4) combined sagittal and unilateral coronal synostosis, and (5) bilateral lambdoid and sagittal synostosis with Mercedes–Benz pattern. All children underwent surgery by the Kartal Craniofacial Team formed by a pediatric neurosurgeon and a plastic surgeon.

 Examples of Rare Craniosynostosis Cases

Sphenofrontal plagiocephaly

The plagiocephaly, an asymmetrical form of craniosynostoses, can present as the anterior plagiocephaly with the unilateral fusion of the coronal suture; the posterior plagiocephaly with the unilateral fusion of the lambdoid suture; and the deformational or positional plagiocephaly developing when the baby's head stays in one position for a long time.

The anterior plagiocephaly that develops as a result of the unilateral fusion of the coronal suture is a common form of simple craniosynostoses. In these cases, the premature fusion may also affect the sphenozygomatic, sphenofrontal, and sphenomastoid sutures that form the coronal ring.[1],[2]

In some rare cases of anterior plagiocephaly, there is a unilateral fusion of the sphenofrontal suture while the coronal suture is intact. Unlike the more common types of plagiocephaly, both coronal sutures appear open and normal in 3D-CT imaging. This reveals that the sphenofrontal suture in the pterion region is unilaterally fused at the affected side [Figure 1].[1],[2],[3]{Figure 1}

Phenotypic characteristics of the cases include deviation of the nasal tip toward the affected side in sphenofrontal plagiocephaly, contrary to the coronal synostosis in which the nose shifts toward the normal side [Figure 2]. In the literature, Sauerhammer et al. in their study reported three children with sphenofrontal plagiocephaly.[4] Bot et al. reported two cases.[5] In Switzerland, de Ribaupierre et al. reported a series of five children with sphenofrontal plagiocephaly. Interestingly, all children were of Turkish citizens of Balkan origin.[1] The only child in our series had paternal origin of Northwestern Turkey. The 5-month-old boy underwent surgery, and a unilateral fronto-orbital advancement and frontal remodeling procedure was undertaken.{Figure 2}

Lambdoid synostosis (unilateral posterior plagiocephaly)

The unilateral posterior plagiocephaly develops due to the premature fusion of the unilateral lambdoid suture.[6],[7],[8],[9] In patients with lambdoid synostosis, deformity of the skull is rather severe and leads to a facial asymmetry similar to the anterior plagiocephaly[10] [Figure 3]. The 3D-CT imaging is important in these patients, revealing the closed lambdoid suture [Figure 4]. Deformational or positional plagiocephaly in infants developing as the result of lying in the same position for long time and anterior plagiocephaly caused by coronal suture involvement should be taken into consideration for differential diagnoses.[7],[9]{Figure 3}{Figure 4}

There are multiple surgical procedures recommended for unilateral posterior plagiocephaly in the literature. These are strip craniectomy, extended linear craniectomy, occipital craniectomy, and transposition using the occipital bone flap technique.[6],[11],[12] A suturectomy was performed to remove the fused lambdoid suture, and then, linear incisions were made toward the parietal and occipital lobes to correct the pathological vector orientations, leading to deformity. No helmet was used postoperatively.

Combined sagittal and metopic synostosis (trigonoscaphocephaly, leptocephaly)

Combined sagittal and metopic synostosis is a highly complex type of synostosis which occurs due to early closure of the sutures that form the midline axis.[13],[14],[15],[16],[17] Vinchon et al. described this rare type of synostosis as a specific clinical entity, naming it as leptocephaly, and classified it under the general topic of atypical synostosis.[14] Dobbs et al. are known to have named it as trigonoscaphocephaly.[16] Here, the clinical picture rather belongs to that of scaphocephaly. Basically, there is an appearance of scaphocephaly due to sagittal suture synostosis, accompanied by the ridging of the frontal midline in the frontal region, most likely due to the premature partial fusion of the metopic suture [Figure 5]. Typically, frontal bossing is not seen in these cases. Rather than belonging to that of a case of trigonocephaly, metopic involvement clinically presents as mild trigonocephaly accompanied by metopic ridging. We believe that the metopic suture is the continuation of the sagittal suture beyond the anterior fontanelle, and vice versa. Thus, the metopic and sagittal sutures constitute one suture, and the synostotic process, in these cases, is effective in the integrity and extension of this suture. In their series of 518 cases, Greene et al. reported 7.5% to be the rare type of combined synostosis, of which 10.3% were metopic-sagittal synostosis.[17] Shimoji et al., reporting of 35 cases, emphasized that such picture should, in fact, not be considered as that rare after all.[15] Terner et al. found, especially in children older than 4.5 months, more intracranial volume reduction in combined metopic and sagittal synostosis as cases compared to those with sagittal synostosis alone, and noted the possibility of neurological disorders.[16] Dobbs et al., reporting nine cases, suggested that the fronto-orbital region should be reshaped in severe cases.[18] In our clinic, we had two cases diagnosed with combined sagittal and metopic synostosis. For these two children, surgical correction of scaphocephaly and metopic suturectomy were performed with removal of midline fused suture band and barrel-stave linear osteotomies.{Figure 5}

Combined sagittal and unilateral coronal synostosis

Combined sagittal and unilateral coronal synostosis cases basically show anterior plagiocephaly due to unilateral coronal suture involvement and scaphocephaly due to sagittal synostosis. In their series, Greene et al. reported that 10.3% of their combined synostosis cases were combined unilateral coronal and sagittal synostosis and indicated this rate to be the same as that of combined metopic and sagittal synostosis.[19] In our single case, the child's 3D-CT revealed both deformities [Figure 6]. The child underwent surgery. The plagiocephaly is corrected with unilateral fronto-orbital advancement and remodeling. The sagittal synostosis was corrected with the removal of the midline and parietal barrel-stave linear cuts.{Figure 6}

Combined bilateral lambdoid and sagittal synostosis (the Mercedes–Benz pattern)

Basically, it is a form of craniosynostosis that involves the sagittal suture and both lambdoid sutures.[19],[20],[21],[22] It still remains as a rare disorder. Neuhauser first described the condition in seven patients in 1976, and in 1998, Moore coined the term “Mercedes − Benz syndrome” in reference to the appearance of fused sutures in 3D-CT imaging[21] [Figure 7]. In Greene et al.'s series, 7.7% of the combined synostosis cases had occurred in this special form.[17] Children present a very different clinical picture. The head height is increased as in turricephaly, together with occipital flattening and a mild form of brachycephaly[21],[22] [Figure 8]. Our single case diagnosed with combined bilateral lambdoid and sagittal synostosis is treated with simple suturectomy and linear barrel-stave incisions performed along sagittal and lambdoid sutures.{Figure 7}{Figure 8}


Some of the rare forms of craniosynostosis are presented in detail. All cases warrant detailed evaluation of the 3D-CT images. As the surgeon experiences increased the number of craniosynostosis cases, the chance of rare cases to be diagnosed increases.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients' parents or legal guardian have given their consent for their images and other clinical information to be reported in the journal. The patients' parents or legal guardian understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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