Craniosynostosis involving the squamous temporal sutures: a rare and possibly underreported etiology for cranial vault asymmetry. J Craniofac Surg. 2010;21:1547-1550. [PMID: 20856046 DOI: 10.1097/SCS.0b013e3181ebe62f]

Surgical Management in Isolated Squamosal Craniosynostosis: A Systematic Review

BACKGROUND

Although craniosynostoses involving the major sutures have been well described, the frequency of isolated minor suture craniosynostoses is much lower. Squamosal craniosynostosis (SQS) is a rare form of cranial synostosis, and the paucity of literature has made the creation of a standardized treatment plan difficult. We present a systematic review of the literature on isolated SQS to identify disease characteristics that lead to a need for operative intervention and to delineate patterns in surgical management.

METHODS

A systematic literature review was performed using the electronic databases of PubMed, Scopus, and MEDLINE and the key words "squamosal AND craniosynostosis," "squamous AND craniosynostosis," "squamosal craniosynostosis, "squamosal suture craniosynostosis," and "isolated squamosal craniosynostosis." Only human studies that described presentation and management of SQS were included. A blinded, 2-reviewer analysis of the articles was performed. Data collected included patient and disease characteristics, imaging workup, and treatment specifics, which were analyzed by descriptive statistics.

RESULTS

A total of 19 studies examining 119 patients with SQS were reviewed, with 97 (82%) multisutural cases and 22 isolated cases (18%). Of the isolated cases, 6 (27%) required surgical craniosynostosis repair, of which 1 (17%) had unilateral sutural involvement and 5 (83%) had bilateral involvement. Of the patients with isolated SQS, 7 (32%) had a congenital syndrome and comprised 33% of patients who required surgical intervention. The nonsyndromic patients with isolated SQS who required surgery presented with a wide array of phenotypic findings; 3 patients underwent some form of cranial vault remodeling, whereas 1 patient underwent ventriculoperitoneal shunt only. Of the 4 nonsyndromic patients with isolated SQS who underwent surgical repair, half required operative intervention because of elevated intracranial pressure and the other half because of dysmorphic head shape.

CONCLUSION

The findings of this updated systematic review suggest a trend toward surgical management in bilateral SQS versus unilateral SQS, and that patients with isolated SQS, previously considered to be a nonsurgical finding, should be carefully monitored, as there remains risk of increased intracranial pressure. Pooled systematic review data suggest isolated SQS has a 27% operative intervention rate, with the presence of coexisting syndromic diagnoses increasing that risk.

Fusion of Lateral Calvarial Sutures on Volume-Rendered Computed Tomography Reconstructions in Patients With Known Craniosynostosis

INTRODUCTION

After treating a child with familial sagittal craniosynostosis, clinocephaly, and bilateral parietomastoid/posterior squamosal suture fusion, the authors wondered if major-suture synostosis and clinocephaly were associated with abnormal fusion of minor lateral calvarial sutures.

METHODS

The authors reviewed all preoperative volume-rendered head computed tomography reconstructions performed for craniosynostosis at their institution from 2010 through 2014 and determined whether the sphenoparietal, squamosal, and parietomastoid sutures were open, partially fused, or fused. The authors determined whether any sutures were abnormally fused based upon a previous study from their center, in which abnormal fusion was defined as either 1 of 3 abnormal fusion patterns or abnormally-early fusion. The authors then determined the rate of abnormal fusion of these sutures and whether abnormal fusion was associated with (1) major-suture craniosynostosis, (2) type of craniosynostosis (sutures involved; single-suture versus multisuture; syndromic versus nonsyndromic), and (3) clinocephaly.

RESULTS

In 97 included children, minor lateral sutures were abnormally fused in 8, or 8.2%, which was significantly higher than in children without craniosynostosis from our earlier study. Abnormal minor lateral suture fusion was not associated with the type of single-suture synostosis or with multisuture synostosis but was associated with syndromic synostosis. Four of 8 children with abnormal minor lateral suture fusion had multisuture synostosis and 6 had syndromic synostosis. Lateral sutures were abnormally fused in 1 of 4 subjects with clinocephaly, which was not significant.

CONCLUSION

Abnormal minor lateral calvarial suture fusion is significantly associated with major-suture craniosynostosis, especially syndromic synostosis.

Management of Minor Suture Craniosynostosis

Although most reported cases of minor suture involvement include multiple sutures, isolated suture involvement has been reported. Morphologic differences such as scaphocephaly and anterior plagiocephaly have been reported. Management should involve proper identification and multidisciplinary treatment. Surgical treatment should involve the expansion of the cranial vault as well as the correction of the deformity.

Bilateral squamosal synostosis: unusual presentation of chromosome 1p12–1p13.3 deletion. Illustrative case

BACKGROUND

Squamosal sutures are minor sutures of the human skull. Early isolated fusion of the sutures (squamosal synostosis) is rarely found.

OBSERVATIONS

The authors report a case of a girl who presented with an abnormal head shape and bilateral squamosal synostosis. Genetic testing revealed a chromosome 1p12–1p13.3 deletion. She has been managed with conservative treatment of the synostosis. She has global developmental delay and multiple anomalies due to the chromosome abnormality.

LESSONS

Isolated squamosal suture synostosis could be an uncommon feature of chromosome 1p12–1p13.3 deletion.

Late presenting bilateral squamosal synostosis

Premature fusion of one or other of the minor sutures can subtly influence the shape of the human skull. Although infrequently reported or not clinically recognized, it can such contribute to a variety of craniofacial dysmorphisms. We herein report a case of late presenting, isolated bilateral synostosis of the squamosal suture dysmorphologies whose presentation mimics aspects of sagittal synostosis.

Bilateral Squamosal Suture Craniosynostosis Presenting with Abducens Nerve Palsy and Severe Papilledema

BACKGROUND

Patients with single-suture or minor suture craniosynostosis are typically asymptomatic at early presentation; intervention is aimed at reducing the risk of elevated intracranial pressure and associated developmental sequelae. Patients may be symptomatic in cases of major multisuture syndromic synostoses or delayed diagnosis. Clinical presentation in this context may include headaches, papilledema, cognitive delay, or behavioral issues. Cranial nerve palsies are atypical symptoms of intracranial hypertension in this patient population.

CASE DESCRIPTION

An 11-month-old, otherwise healthy girl presented with bilateral severe papilledema and left abducens nerve palsy owing to nonsyndromic near-complete bilateral squamosal suture synostosis with associated incomplete sagittal and right lambdoid synostoses. The patient underwent urgent open cranial expansion, with resolution of her papilledema and improvement in eye position and motility.

CONCLUSIONS

Cranial nerve palsies may be presenting symptoms of intracranial hypertension in patients with craniosynostosis. Multidisciplinary evaluation and treatment is paramount for appropriate management.

The Significance of Squamosal Suture Synostosis

The squamosal suture is one of the lateral minor skull sutures, separating the parietal and squamous temporal bones. While the phenotypic appearances and sequelae of synostosis of the major cranial vault sutures are well documented, little is reported concerning synostosis of the squamosal suture (SQS). The aim of this study was to determine the frequency of squamosal suture synostosis, and to document the significance of this entity.A retrospective review of the diagnostic imaging for all new pediatric patients (aged ≤16 years) referred to the Oxford Craniofacial Unit between January 2008 and February 2013 was completed to identify patients with SQS. Computed tomography (CT) imaging was available in 422 patients and the axial and three-dimensional reconstructed images reviewed.Squamosal suture synostosis was confirmed in 38 patients (9%). It was present in conjunction with major suture synostosis in 33 patients and in isolation in 5. The incidence increased with age. It was more common in patients with syndromic craniosynostosis (18%) and associated syndromic conditions (36%) than in those with isolated major suture synostosis (6%). It was found to occur with coronal, lambdoid, and sagittal synostosis, but was most frequent with multisuture fusion patterns. Squamosal suture synostosis was not associated with a consistent calvarial deformity either in isolation or when associated with a major suture fusion. No patient underwent surgery specifically to correct SQS.In conclusion, contrary to previous reports, squamosal suture synostosis is a relatively frequent finding in the general case mix of a typical craniofacial unit, but is of limited clinical significance.

Craniosynostosis as a clinical and diagnostic problem: molecular pathology and genetic counseling

Craniosynostosis (occurrence: 1/2500 live births) is a result of premature fusion of cranial sutures, leading to alterations of the pattern of cranial growth, resulting in abnormal shape of the head and dysmorphic facial features. In approximately 85% of cases, the disease is isolated and nonsyndromic and mainly involves only one suture. Syndromic craniosynostoses such as Crouzon, Apert, Pfeiffer, Muenke, and Saethre-Chotzen syndromes not only affect multiple sutures, but are also associated with the presence of additional clinical symptoms, including hand and feet malformations, skeletal and cardiac defects, developmental delay, and others. The etiology of craniosynostoses may involve genetic (also somatic mosaicism and regulatory mutations) and epigenetic factors, as well as environmental factors. According to the published data, chromosomal aberrations, mostly submicroscopic ones, account for about 6.7-40% of cases of syndromic craniosynostoses presenting with premature fusion of metopic or sagittal sutures. The best characterized is the deletion or translocation of the 7p21 region containing the TWIST1 gene. The deletions of 9p22 or 11q23-qter (Jacobsen syndrome) are both associated with trigonocephaly. The genes related to the pathogenesis of the craniosynostoses itself are those encoding transcription factors, e.g., TWIST1, MSX2, EN1, and ZIC1, and proteins involved in osteogenic proliferation, differentiation, and homeostasis, such as FGFR1, FGFR2, RUNX2, POR, and many others. In this review, we present the clinical and molecular features of selected craniosynostosis syndromes, genotype-phenotype correlation, family genetic counseling, and propose the most appropriate diagnostic algorithm.

Squamosal Craniosynostosis: Defining the Phenotype and Indications for Surgical Management

BACKGROUND

Squamosal craniosynostosis is seldom reported in the craniofacial literature. Given that this is an uncommon diagnosis, phenotype and management remain unclear. The authors present a case series and review the literature to define the phenotype and management of these patients.

METHODS

We retrospectively reviewed 7 patients from our institution and systematically reviewed all published cases of squamosal craniosynostosis. Demographics, medical history, imaging, clinical presentation, subsequent workup, and treatment were examined and analyzed.

RESULTS

A comprehensive review of the literature yielded a total of 31 cases (including our new series) of squamosal craniosynostosis. Average age of presentation was 25.3 months, 52% of female patients, 74% of cases with bilateral squamosal involvement, 44% syndromic, 39% isolated squamosal (vs 61% multisutural). Overall, 56% of cases were handled surgically, whereas 44% were managed conservatively. Thirty-three percent of surgical cases required multiple operations. One patient with isolated bilateral squamosal craniosynostosis developed elevated intracranial pressure, requiring cranial vault remodeling.

CONCLUSIONS

Squamosal craniosynostosis frequently presents in a delayed fashion with nonsyndromic, bilateral involvement. In isolated bilateral squamosal cases, the associated phenotype is frontal prominence, occipital flattening, scaphocephalic tendency (low-end normocephalic cranial index), and superior parietal cornering. Evaluation of clinical signs and computed tomography imaging guides management, as evidence of increased intracranial pressure may indicate need for cranial vault expansion. Although previous literature suggests that nonsyndromic cases are nonsurgical, the majority of cases reviewed required surgical intervention, including our case of isolated bilateral squamosal craniosynostosis. We recommend vigilant management in patients with squamosal craniosynostosis, even those with isolated squamosal involvement.

Squamosal Suture Synostosis: Incidence, Associations, and Implications for Treatment

Squamosal suture craniosynostosis is thought to be a relatively rare entity. In the authors' experience, it is underreported in imaging examinations and the existing literature. The authors sought to determine the incidence of squamosal synostosis, whether it is increasing in frequency, and its relationship with synostosis of the major calvarial sutures.Patients undergoing computed tomography imaging for suspected craniosynostosis over a 15-year period were reviewed by a plastic surgeon and pediatric neuroradiologist. Patients with synostosis of the squamosal sutures were identified and involvement of additional sutures, gender, and the presence of a known syndromic diagnosis were recorded. Patients greater than 4 years of age or those with prior craniofacial surgery were excluded.One hundred twenty-five patients met inclusion criteria, 26 of whom had squamosal suture synostosis (26/125, 20.8%). Squamosal synostosis was found in isolation in 3 patients (3/26, 11.5%), with 1 additional major suture in 10 patients (10/26, 38.5%), and ≥2 major sutures in 13 patients (13/26, 50%). Squamosal synostosis was more common in patients with a syndromic diagnosis (11/26 syndromic, 15/99 nonsyndromic, P < 0.001). Eleven of 26 patients with squamosal synostosis were identified in the radiology report (42.3%).Craniosynostosis of the squamosal suture is much more common than previously reported and can contribute to abnormal head shape in isolation, or in combination with major sutures. Squamosal suture synostosis is underdiagnosed clinically and radiologically, although insufficient evidence exists to determine if its true incidence is increasing.

Unilateral Pterional Polycraniosynostosis Treated with Craniectomy and Helmet Therapy

Supplemental Digital Content is available in the text.

Craniosynostosis is a condition in which one or more of the cranial sutures have fused prematurely, affecting the growth pattern and contours of the infant skull. The pterion is the junction of temporal, frontal, parietal, and sphenoid bones of the skull. We present a case of unilateral pterional craniosynostosis, which was treated with strip craniectomy and helmet therapy.

Squamous Suture Synostosis: A Review With Emphasis on Cranial Morphology and Involvement of Other Cranial Sutures

Squamosal suture synostosis has received little attention, potentially due to its rare nature. The authors present here a clinical report of isolated unilateral squamosal suture synostosis and a literature review, which produced 6 articles describing 33 patients of squamosal synostosis.Of the reported patients, 15 were associated with a craniofacial syndrome, 10 were nonsyndromic, and 8 were not specified. The cranial morphology varied greatly and only 1 patient was consistent with the morphology predicted by Virchow law-decreased vertical growth with compensatory ipsilateral longitudinal growth (manifesting as occipital and possibly frontal zygomatic bulging). Additional suture synostoses were observed in 36.3% of nonsyndromic and 80% of syndromic patients, suggesting that either squamosal synostosis may have an effect on other sutures, or more likely, only the most severe patients are recognized and reported.Surgical and nonsurgical interventions have found limited utility due to the subtle nature of the cranial defects and a lack of increased intracranial pressure, with a conservative follow-up course being the preferred treatment.

Bilateral squamosal suture synostosis: A rare form of isolated craniosynostosis in Crouzon syndrome

Craniosynostosis is a pathologic condition which is characterized by the premature fusion of cranial sutures. It may occur alone or in association with other anomalies making up various syndromes. Crouzon syndrome is the most common craniosynostosis syndrome. Bicoronal sutures fusion is most commonly involved in Crouzon syndrome. There have only been a handful of cases of squamosal suture synostosis described in the surgery literature with the few ones described in Crouzon syndrome associated with other types of craniosynostosis. To the best of our knowledge, we are presenting the first case of isolated bilateral squamosal suture synostosis in a patient with Crouzon syndrome in a radiology journal with emphasis on its radiological appearance.