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Updated: Jun 6, 2026
Step By Step: Microsurgical training method combining two nonliving animal models
Published on: May 9, 2015
How Often Is Enough? Training Frequency Required to Maintain Microsurgical Anastomosis Skills: A Longitudinal
Ayumu Yamaoka1, Katsuya Komatsu1, Aya Kanno1
1Department of Neurosurgery, Sapporo Medical University, Sapporo, Hokkaido, Japan.
Background And Objectives:
Microsurgical anastomosis remains an essential technique for selected cerebrovascular conditions, yet opportunities for operative experience are limited. Off-the-job training is therefore critical for skill acquisition. Although training volume has been widely discussed, the optimal practice interval for skill retention and acquisition has not been quantitatively established. The aim of this study was to identify stage-specific practice intervals for microsurgical anastomosis training using longitudinal self-practice performance data.
Methods:
A longitudinal self-practice log comprising 1118 end-to-side anastomosis sessions performed by a single neurosurgeon over 6 years was analyzed. Anastomosis time was normalized using multivariable regression with spline modeling to adjust for task difficulty and learning progression. Training was divided into early, mid, and late phases, each corresponding to approximately 2 years of practice. Performance was compared across practice intervals of 1, 2, 3, 4, and 5 days or longer within each phase using nonparametric tests. Noninferiority analyses were conducted with the 1-day interval as reference and a prespecified margin of 10%.
Results:
In the early phase, longer practice intervals were associated with significantly prolonged normalized anastomosis time compared with daily training. By contrast, interval-dependent differences largely disappeared in the mid and late phases. Noninferiority analyses demonstrated that most extended intervals in these later phases were not inferior to daily practice. Sensitivity analyses using wider margins (15% and 20%) confirmed these findings across all evaluated intervals.
Conclusion:
The optimal practice interval for microsurgical anastomosis training is stage dependent. Intensive daily practice is required during early skill acquisition. In the mid and late stages, performance remained stable even as practice intervals were gradually lengthened, suggesting that moderate extension of training intervals may be tolerated after proficiency is established. These findings provide an evidence-based framework for designing realistic, stage-specific training schedules in microsurgical education.
