Fully Endoscopic Supraorbital Approach for Anterior Cranial Base Meningiomas.

BACKGROUND: Anterior cranial base meningiomas include those meningiomas originating from the tuberculum sellae, the planum sphenoidale, or the olfactory groove, with surgical excision being the main treatment modality for these tumors. Conventional microscopic and endoscope-assisted versions of the supraorbital keyhole approach via an eyebrow incision emerged into minimally invasive options that are frequently utilized nowadays for treating these tumors. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Notwithstanding, the fully endoscopic or endoscope-controlled version of the supraorbital keyhole approach is not routinely practiced by neurosurgeons, with few series published so far. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic supraorbital approach for anterior cranial base meningiomas. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic excision of anterior cranial base meningiomas via supraorbital approach were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic supraorbital approach for anterior cranial base meningiomas was formulated. CONCLUSION: The fully endoscopic supraorbital approach for anterior cranial base meningiomas has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Tribal Founder EMC1 Variant in 5 Kuwaiti Families Expands Phenotypic Spectrum of EMC1-Related Disorder.

Background and Objectives: The endoplasmic reticulum (ER) membrane protein complex is a conserved multisubunit transmembrane complex that enables energy-independent insertion of newly synthesized membrane proteins into ER membranes, mediating protein folding, phospholipid transfer from ER to mitochondria, and elimination of misfolded proteins. The first subunit of EMC (EMC1) is encoded by EMC1. Both monoallelic de novo and biallelic EMC1 variants have been identified to cause cerebellar atrophy, visual impairment, and psychomotor retardation (CAVIPMR) [OMIM #616875]. Eight families with biallelic EMC1 variants and CAVIPMR have been reported. Here, we describe 8 individuals from 5 Kuwaiti families from the same tribe, with the previously reported homozygous pathogenic missense EMC1 variant [c.245C>T:p.(Thr82Met)] and CAVIPMR. Methods: Proband exome sequencing was performed in 3 families, while targeted molecular testing for EMC1 [c.245C>T:p.(Thr82Met)] variant was performed in the other 2 families based on strong clinical suspicion and tribal origin. Sanger sequencing confirmed variant segregation with disease in all families. Results: We identified 8 individuals from 5 Kuwaiti families with the homozygous pathogenic EMC1 variant [c.245C>T:p.(Thr82Met)] previously reported in a Turkish family with CAVIPMR. The variant was absent from Kuwait Medical Genetic Center database, thus unlikely to represent a population founder allelic variant. The average age at symptom onset was 11 weeks, with all families reporting either visual abnormalities, hypotonia, and/or global developmental delay (GDD) as the presenting features. Shared clinical features included GDD (8/8), microcephaly (8/8), truncal hypotonia (8/8), visual impairment (7/7), and failure to thrive (7/7). Other common features included hyperreflexia (5/6; 83%), peripheral hypertonia (3/5; 60%), dysmorphism (3/6; 50%), epilepsy (4/8; 50%), and chorea (3/8; 36%). Brain imaging showed cerebellar atrophy in 4/7 (57%) and cerebral atrophy in 3/6 (50%) individuals. Discussion: The presence of exact biallelic homozygous EMC1 variant in 5 Kuwaiti families from the same tribe suggests a tribal founder allelic variant. The clinical features in this study are consistent with the phenotypic spectrum of EMC1-associated CAVIPMR in previous reports. The presence of chorea, first noted in this study, further expands the phenotypic spectrum. Our findings emphasize the importance of targeted EMC1 variant [c.245C>T:p.(Thr82Met)] testing for infants from affected tribe who present with visual impairment, GDD, and hypotonia.