Severe Constricted Head – An Extreme Form Of Crouzon Syndrome Posing Challenging Fronto-Orbital Advancement : Case Reports

Background : Constricted head or cloverleaf deformity in Crouzon syndrome is a severe form of the syndrome involving trilobed coronal and lambdoid synostosis. Crouzon syndrome with acanthosis nigricans is distinct from the classic Crouzon syndrome, characterized by thick and dark skin in body folds. The major problems resulting from constricted head are related to craniostenosis, orbitostenosis developing from abnormalities of the skull base associated with progressive rise in intracranial and intraorbital pressures which could progress to hydrocephalus and cerebellar herniation. Case: Two cases with severe Crouzon syndrome were reported. The first was a five month old girl associated with acanthosis nigricans and the other was a sixteen month old boy, both whose phenotypic expressions were at the extreme severe end of the disease spectrum. On examination there was serious corneal exposure, visual loss, severely narrow head, midface hypoplasia, and beaked nose. CT scan showed typical cloverleaf skull, expanded middle cranial fossa, foreshortened anterior and posterior fossae and honeycomb appearance in the occiput involving pansutural synostosis and extensive copper beaten deformity from the high intracranial pressure . Both were complicated with hydrocephalus requiring ventriculoperitoneal shunt. This required an arduous effort in releasing the brain from the multiply punctured calvaria, avoiding excessive dural tear and bleeding and ultimately preserving the brain. Excessive bleeding was also caused by the raised ICP. Both patients are planned to undergo occipital expansion three months later. Conclusion: Severely constricted head in Crouzon syndrome is an extreme manifestation and late stage of the syndrome which not only will result in irreversible complication but will require meticulous surgical technique.

Lambdoid synostosis: endoscopic craniectomy

Lambdoid craniosynostosis leads to significant deformational changes of the calvaria and cranial fossae. Surgery used to treat the condition typically consists of a calvarial vault remodeling (CVR) procedure whereby the entire occiput is removed and reshaped along with a bandeau advancement to give the patient a rounded occiput. As an option, this video presents the minimally invasive endoscopic craniectomy used at the author's institution, which was developed there and has been successfully used for 25 years. This procedure is simple and can be done rapidly, with minimal to no blood loss. The video details the key steps necessary to successfully perform the procedure. The video can be found here: https://vimeo.com/515746378.

Unexpected role of SIX1 variants in craniosynostosis: expanding the phenotype of SIX1-related disorders

BackgroundPathogenic heterozygous SIX1 variants (predominantly missense) occur in branchio-otic syndrome (BOS), but an association with craniosynostosis has not been reported.MethodsWe investigated probands with craniosynostosis of unknown cause using whole exome/genome (n=628) or RNA (n=386) sequencing, and performed targeted resequencing of SIX1 in 615 additional patients. Expression of SIX1 protein in embryonic cranial sutures was examined in the Six1nLacZ/+ reporter mouse.ResultsFrom 1629 unrelated cases with craniosynostosis we identified seven different SIX1 variants (three missense, including two de novo mutations, and four nonsense, one of which was also present in an affected twin). Compared with population data, enrichment of SIX1 loss-of-function variants was highly significant (p=0.00003). All individuals with craniosynostosis had sagittal suture fusion; additionally four had bilambdoid synostosis. Associated BOS features were often attenuated; some carrier relatives appeared non-penetrant. SIX1 is expressed in a layer basal to the calvaria, likely corresponding to the dura mater, and in the mid-sagittal mesenchyme.ConclusionCraniosynostosis is associated with heterozygous SIX1 variants, with possible enrichment of loss-of-function variants compared with classical BOS. We recommend screening of SIX1 in craniosynostosis, particularly when sagittal±lambdoid synostosis and/or any BOS phenotypes are present. These findings highlight the role of SIX1 in cranial suture homeostasis.

Posterior calvarial distraction for complex craniosynostosis and cerebellar tonsillar herniation

OBJECTIVEChildren with syndromic, multisuture, and lambdoid craniosynostosis undergoing calvarial surgery often have Chiari malformation type I (CM-I) (or cerebellar tonsillar herniation). The optimal management of this patient group, including the surgical techniques and timing of surgery, remains uncertain. Posterior calvarial distraction (PCD) is an effective method to increase the supratentorial cranial volume and improve raised intracranial pressure in children with complex craniosynostosis. This study investigated the efficacy of PCD in posterior fossa (PF) volume expansion and treatment of CM-I and associated syringomyelia (syrinx) in this group of children.METHODSThis retrospective study included patients who were surgically treated between 2006 and 2015. Over 10 years, 16 patients with multisuture synostosis, lambdoid synostosis, or craniosynostosis associated with a confirmed genetic syndrome, and a concurrent CM-I, were included. The mean age at the time of surgery was 5.1 years (range 8 months–18 years). Fourteen patients had pansynostosis and 2 had lambdoid synostosis. Eight had a confirmed syndromic diagnosis (Crouzon in 8, Apert in 4, Pfeiffer in 1, and Saethre-Chotzen in 1). Ten patients had raised intracranial pressure; 4 had syringomyelia.RESULTSThe average clinical follow-up was 50 months (range 9–116 months). Clinically, 9 patients improved, 7 remained stable, and none deteriorated. The average distraction distance was 23 mm (range 16–28 mm). The PF anterior-posterior (AP) distance/width ratio increased from 0.73 to 0.80 mm (p = 0.0004). Although an osteotomy extending inferior to the torcula (compared with superior) was associated with a larger absolute PF AP distance increase (13 vs 6 mm, p = 0.028), such a difference was not demonstrable when the PF AP distance/width ratio was calculated. Overall, the mean tonsillar herniation improved from 9.3 to 6.0 mm (p = 0.011). Syrinx dimensions also improved in the AP (from 7.9 to 3.1 mm) and superior-inferior (from 203 to 136 mm) dimensions. No patients required further foramen magnum decompression for CM. Of the 16 patients, 2 had subsequent frontoorbital advancement and remodeling, of which 1 was for volume expansion and 1 was for cosmetic purposes. Two patients required CSF shunt insertion after PCD.CONCLUSIONSFollowing PCD, PF volume increased as well as supratentorial volume. This morphometric change was observed in osteotomies both inferior and superior to the torcula. The PF volume increase resulted in improvement of cerebellar tonsillar herniation and syrinx. PCD is an efficacious first-line, single-stage treatment for concurrent pansynostosis and lambdoid craniosynostosis, CM-I, and syrinx.

Comparative analysis of cranial vault remodeling versus endoscopic suturectomy in the treatment of unilateral lambdoid craniosynostosis

OBJECTIVEUnilateral lambdoid synostosis is the premature fusion of a lambdoid suture or sutures and represents the least common form of craniosynostosis, occurring in 1 in 40,000 births. Cranial vault remodeling (CVR) and endoscopic suturectomy with helmet therapy (ES) are surgical approaches that are used to allow for normal brain growth and improved craniofacial symmetry. The authors conducted a comparative outcomes analysis of patients with lambdoid synostosis undergoing either CVR or ES.METHODSThe authors conducted a retrospective consecutive cohort study of patients with nonsyndromic lambdoid synostosis who underwent surgical correction identified from a single-institution database of patients with craniosynostosis seen between 2000 and 2018. Cranial growth was measured in head circumference percentile and z score.RESULTSNineteen patients (8 female and 11 male) with isolated unilateral lambdoid synostosis were identified (8 right and 11 left). Six underwent CVR and 13 underwent ES. No statistically significant differences were noted between surgical groups with respect to suture laterality, the patient’s sex, and length of follow-up. Patients treated with ES presented and underwent surgery at a younger age than those treated with CVR (p = 0.0002 and p = 0.0001, respectively). Operating and anesthesia time, estimated blood loss, and ICU and total hospital days were significantly lower in ES (all p < 0.05). No significant differences were observed in pre- and postoperative head circumference percentiles or z scores between groups up to 36 months postoperatively. No patients required reoperation as of last follow-up.CONCLUSIONSEndoscopic management of lambdoid synostosis is safe, efficient, and efficacious in terms of intraoperative and long-term cranial growth outcomes when compared to CVR. The authors recommend this minimally invasive approach as an option for correction of lambdoid synostosis in patients presenting early in their course.

Rare health conditions 33: lambdoid synostosis, traumatic retrograde amnesia and malaria

The purpose of this series is to briefly highlight a range of rare health conditions. Rare health conditions are those that affect no more and usually less than 1 person in every 2000 and many HCAs and nurses will encounter some of these conditions, given the high number of these conditions. This 33rd article will explore three of these conditions: lambdoid synostosis, traumatic retrograde amnesia and malaria.