What Is the Appropriate Sample Size in Human Cadaveric Studies? A Quantitative Review of 770 Articles.

Abstract

Determining an appropriate sample size in human cadaveric studies remains a long-standing and unresolved challenge. Unlike other basic science fields, anatomical research is constrained by factors such as limited human donor availability, cultural considerations, and ethical restrictions. Despite these limitations, researchers are often asked to justify sample sizes, yet no standardized guidelines currently exist. To quantitatively assess sample sizes in recent human cadaveric studies and propose evidence-based recommendations for future research, a PubMed search was conducted on February 26, 2024, using the term human cadaveric study. The articles published in 2023 and 2024 were screened, yielding 770 eligible studies. Data extracted included the total sample size, number of classified groups, and journal impact factor (IF). Descriptive statistics, linear regression, and correlation analyses were performed. Continuous variables were summarized using medians and interquartile ranges (IQR). The median sample size was 11.5 (IQR: 7-20), and 47.9% of studies used 10 or fewer specimens. The median number of classified groups was 3 (IQR: 2-4). Linear regression showed that studies dividing specimens into 2-6 groups often failed to meet the recommended sample size per group based on regression modeling. No significant correlation was found between sample size and journal IF (r = -0.062, p = 0.115). Most cadaveric studies rely on small sample sizes due to inherent constraints, yet many still attempt a subgroup analysis without sufficient statistical power. Although flexibility is essential in anatomical research, we recommend a minimum total sample size of 10 for basic studies and at least five samples per group for those involving classification. Cadaveric sample size alone does not predict journal impact, highlighting the importance of methodological rigor over quantity.