Supplementary Material for: A novel decision-making protocol for the prediction of sperm retrieval in Klinefelter's Syndrome patients

Introduction To develop a preliminary, decision-making protocol capable of predicting sperm retrieval success in non-mosaic Klinefelter's syndrome (KS) patients. Main outcome was to identify predictors of successful sperm retrieval and to build a decision-making protocol capable of predicting this success by assessing several variables including age, testicular volume and pre-operative hormonal responses. Methods A retrospective cohort study included all men with non-mosaic KS who were treated with recombinant hCG and then underwent microdissection testicular sperm extraction (micro-TESE) between December 2019 and March 2023. Results Thirty-eight patients who were treated medically with rec-hCG prior to their micro-TESE were included. Sperm was retrieved successfully from 28 patients (73.7%). Initial testosterone differences between the groups were small and not significant, the mean pre-op (post hormonal treatment) testosterone between the two groups was significant (P =0.001). We then built a decision making tree, in which Testosterone change was the primary determining factor for successful sperm retrieval, testicular volume was a contributory secondary variable, and age was a tertiary consideration in cases of low testicular volume. Using this model, we observed the highest success rates (97%) in men with testosterone change of 9 nmol/l or more and testicular volume of 3 cc or more. on the other hand, men with no testosterone change with hormonal treatment, low testicular volume who were 25 years old or more had a success rate of only 63%. Conclusion This study proposes a preliminary, decision-making protocol capable of predicting sperm retrieval success in non-mosaic KS patients. This model can be used as part of an individualized counselling approach. External validation is essential to corroborate our preliminary results.