Diagnostic Value Of Horizontal Sections Compared To Vertical And Ho-Vert Sections In Diagnosing Scarring And Non-scarring Alopecia:a Systematic Review And Meta-analysis

Backgrouod Histopathological diagnosis of scalp biopsies remains a challenging area of dermatopathology. Several recent studies have described the benefits of different sectioning techniques in assessing scalp specimens, but the application of these techniques is still under clinical investigation. The objectives of this study were to review published literature and evaluate the diagnostic value of different sectioning techniques (horizontal, vertical or Ho-Vert sections) in the diagnosis of scarring and non-scarring alopecia.Methods PubMed, EMBASE, Web of Science, Sciencedirect, Scopus and the Cochrane Library Central were searched for published articles. The last search was undertaken on June 1,2015. The search terms were "Alopecia OR Hair loss OR Baldness" and "Section". These keywords were identified in the medical subject heading, title or abstract. To identify additional relevant studies, the literature search was also performed manually. Total cases, diagnosed cases and diagnostic rates were extracted from each included study. Pooled diagnostic rates with 95% confidence intervals (CI) were used to evaluate the value of different sectioning techniques, and we tested for publication bias and heterogeneity.Results Most studies had a suboptimal design. As to diagnosing non-scarring alopecia, there were 8 horizontal and 8 vertical section studies. The pooled diagnostic rates were 0.81 (95% CI=0.70-0.92) and 0.76 (95% CI=0.60-0.93) respectively, and extensive heterogeneity existed among these studies. In diagnosing scarring alopecia there were 3 horizontal and 5 vertical sectioning studies. The pooled diagnostic rates were 0.86 (95% CI=0.66-1) and 0.90 (95% CI=0.82-0.98) respectively and heterogeneity was also observed.Conclusions Based on published studies, no significant difference exists between horizontal and vertical sectioning techniques in diagnosing alopecia. Whereas most studies had a suboptimal design, future studies in this area would benefit from a scientific approach and standardized measurements to explore the value of horizontal, vertical and Ho-Vert sectioning.