title: Lateral and posterolateral foraminal variations of the atlas: A meta-analysis.
abstract: The lateral (LF) and posterolateral (PLF) foramina are anatomical variants of the atlas. Both variants have been implicated in multiple neurological conditions including vertebrobasilar insufficiency, with symptoms such as dizziness, syncope, auditory and visual disturbances and paresis. The aim of this study was to conduct a systematic meta-analysis on the prevalence and anatomical characteristics of the LF and PLF. An extensive search of the major electronic databases was conducted to identify all studies that reported relevant data on the LF and PLF. No date or language restrictions were applied. Data on the prevalence, type (complete and incomplete), side, gender, and laterality of the LF and PLF, when available, were extracted and pooled into a meta-analysis. A total of 33 studies (n=10,190 subjects) were included in the quantitative analysis. The overall pooled prevalences of complete LF and PLF were 2.6% (95%CI: 2.1-3.1) and 1.2% (95%CI:0.6-2.0), respectively, while the overall pooled prevalence of the incomplete LF was 2.7% (95%CI:1.3-4.4) and the incomplete PLF was 0.7% (95%CI:0.0-1.8). When there was a complete PLF, a contralateral PLF (complete or incomplete) was found in 32.8% of cases. The geographical distribution of both variants was variable. The findings of this study provide an evidence-based foundation of anatomical knowledge of the two variants of the atlas. We recommend that physicians consider the possible role of the LF and PLF during the diagnosis of various neurological disturbances, especially in situations when all other possible explanations for the symptoms have been excluded.
authors.affiliation: International Evidence-Based Anatomy Working Group, Krakow, Poland; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Przemysław A
authors.initials: PA
authors.lastname: Pękala
authors.affiliation: International Evidence-Based Anatomy Working Group, Krakow, Poland; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland. Electronic address: bmhenry55@gmail.com.
authors.forename: Brandon Michael
authors.initials: BM
authors.lastname: Henry
authors.affiliation: International Evidence-Based Anatomy Working Group, Krakow, Poland; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Jakub R
authors.initials: JR
authors.lastname: Pękala
authors.affiliation: International Evidence-Based Anatomy Working Group, Krakow, Poland; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Saganiak
authors.affiliation: International Evidence-Based Anatomy Working Group, Krakow, Poland; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Dominik
authors.initials: D
authors.lastname: Taterra
authors.affiliation: International Evidence-Based Anatomy Working Group, Krakow, Poland; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Jerzy A
authors.initials: JA
authors.lastname: Walocha
authors.affiliation: Seattle Science Foundation, Seattle, WA, USA.
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Krzysztof A
authors.initials: KA
authors.lastname: Tomaszewski
mesh_terms: D001270:Cervical Atlas / Q000033:anatomy & histology*; D006801:Humans
keywords: Atlas; Lateral foramen; Posterolateral foramen; Vertebrobasilar insufficiency