Comparison of Magnification in Primary Digital Nerve Repair: Literature Review, Survey of Practice Trends, and Assessment of 90 Cadaveric Repairs

PurposeTo review published clinical outcomes and current practice trends and to assess the quality of cadaveric digital nerve repairs using either loupe or microscopic magnification.MethodsPublished clinical outcomes of digital nerve repair accounting for magnification level were reviewed. Members of the American Society for Surgery of the Hand were surveyed regarding their current surgical practices. Ninety cadaveric digital nerve repairs were performed by 9 hand surgeons using loupe or microscopic magnification and evaluated by a visual grading scale. Univariate and multivariate analyses were used to evaluate repairs.ResultsWe examined 6 publications involving 130 repairs with loupes (4–6×) and 255 repairs with microscopes. Univariate analysis revealed no statistically superior clinical outcomes using high-powered loupes (4–6×) versus microscopic magnification, with no data on lower-magnification loupes more commonly used in practice. Survey data indicated that 52% of hand surgeons use microscopes and 48% use loupes, with 78% using 2.5 to 3.5× magnification. Univariate analysis of the cadaveric repairs demonstrated excellent repairs in 60% of microscope repairs versus 29% of loupe repairs. Multivariate analysis determined that microscopic magnification was 3.9 times more likely than loupes to yield an excellent repair. The surgeon, level of training, repair time, and stitches per repair were not significantly related to an excellent repair.ConclusionsOur study indicated that microscope use produces superior quality digital nerve repair. Approximately half of hand surgeons use loupes in current practice, mostly at low magnification (2.5–3.5×). In this context, a higher level of magnification may be positively correlated with better clinical outcomes.Type of study/level of evidenceTherapeutic III.