Branching patterns of the superficial fibular nerve: an anatomical study with meta-analysis

Purpose To review variations regarding the branching patterns of the superficial fibular nerve (SFN) concerning the deep fascia of leg and to the ankle joint level. Methods Searches were conducted in PubMed, Scopus, Lilacs, and Web of Science databases on October 14th, 2021. We followed the PRISMA guidelines to report this review. Articles with data on SFN variations prevalence were included. The data were extracted and pooled into a meta-analysis. We also dissected 60 formalin-fixed Brazilian fetuses ( n = 120 lower limbs). Results Twenty-five studies ( n = 1272 lower limbs) comprised this review. Concerning the SFN branching at the deep fascia, Type 1 variation (in which the SFN pierces the fascia as a single nerve trunk) had a pooled prevalence of 86.4% (95% CI 84.5–88.2), while Type 2 had a pooled prevalence of 13.6% (95% CI 11.8–15.5). At the ankle joint level, Type 2 variation (in which the SFN branches off below the joint level) was the most common anatomical pattern, with a pooled prevalence of 78.7% (95% CI 74.5–82.7). Conclusion Typically, the SFN branches off between its exit from the deep fascia and the ankle joint level. The SFN variations have great importance for surgeries, such as arthroscopies and fascia release surgeries, regional anesthesia, and clinical evaluation of SFN entrapment syndrome.