BACKGROUND ICSI is currently the most commonly used assisted reproductive technology, accounting for 70-80% of the cycles performed. This extensive use, even excessive, is partly due to the high level of standardization reached by the procedure. There are, however, some aspects that deserve attention and can still be ameliorated. The aim of this systematic review was to evaluate the results of available publications dealing with the management of specific situations during ICSI in order to support embryologists in trying to offer the best laboratory individualized treatment. METHODS This systematic review is based on material obtained by searching PUBMED between January 1996 and March 2015. We included peer-reviewed, English-language journal articles that have evaluated ICSI outcomes in the case of (i) immature oocytes, (ii) oocyte degeneration, (iii) timing of the various phases, (iv) polar body position during injection, (v) zona-free oocytes, (vi) fertilization deficiency, (vii) round-headed sperm, (viii) immotile sperm and (ix) semen samples with high DNA fragmentation. RESULTS More than 1770 articles were obtained, from which only 90 were specifically related to the issues developed for female gametes and 55 for the issues developed for male gametes. The studies selected for this review were organized in order to provide a guide to overcome roadblocks. According to these studies, the injection of rescue metaphase I oocytes should be discouraged due to poor clinical outcomes and a high aneuploidy rates; laser-assisted ICSI represents an efficient method to solve the high oocyte degeneration rate; the optimal ICSI timing and the best polar body position during the injection have not been clarified; injected zona-free oocytes, if handled carefully, can develop up to blastocyst stage and implant; efficient options can be offered to patients who suffered fertilization failure in previous conventional ICSI cycles. Most controversial and inconclusive are data on the best method to select a viable spermatozoa when only immotile spermatozoa are available for ICSI and, to date, there is no reliable approach to completely filter out spermatozoa with fragmented DNA from an ejaculate. However, most of the studies do not report essential clinical outcomes, such as live birth, miscarriage and fetal abnormality rate, which are essential to establish the safety of a procedure. CONCLUSIONS This review provides the current knowledge on some controversial technical aspects of the ICSI procedures in order to improve its efficacy in specific contexts. Notwithstanding that embryologists might benefit from the approaches presented herein in order to improve ICSI outcomes, this area of expertise still demands a greater number of well-designed studies, especially in order to solve open issues about the safety of these procedures.

中文翻译：

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从过去到未来的ICSI程序：对更具争议性的方面的系统回顾。

背景技术ICSI是目前最常用的辅助生殖技术，占所执行周期的70-80％。这种广泛的使用，甚至过度使用，部分是由于该过程达到了很高的标准化水平。但是，有些方面值得关注，并且仍然可以改善。该系统评价的目的是评估有关ICSI期间特定情况管理的现有出版物的结果，以支持胚胎学家尝试提供最佳的实验室个体化治疗。方法本系统综述基于1996年1月至2015年3月在PUBMED上获得的资料。我们纳入了同行评审的英语期刊文章，这些文章对（i）未成熟卵母细胞，（ii）卵母细胞变性的情况下的ICSI结果进行了评估。 ，（iii）不同阶段的时机，（iv）注射时的极体位置，（v）无透明带卵母细胞，（vi）受精不足，（vii）圆头精子，（viii）不育精子和（ix）精液DNA片段化程度高的样品。结果获得了1770篇文章，其中只有90篇与女性配子有关的问题特别相关，有55篇与男性配子有关的问题特别相关。为这次审查选择的研究进行了组织，以提供克服障碍的指南。根据这些研究，由于临床预后差和非整倍体率高，不建议注射救救中期I卵母细胞。激光辅助ICSI是解决高卵母细胞变性率的有效方法。注射过程中的最佳ICSI时机和最佳极体位置尚未阐明；如果小心处理，注射的无透明带卵母细胞可发育到胚泡阶段并植入。可以为以前的常规ICSI周期中受精失败的患者提供有效的选择。最具争议性和不确定性的数据是当仅运动型精子可用于ICSI时，选择可行的精子的最佳方法的数据，迄今为止，还没有可靠的方法来从射精中用片段化的DNA完全滤出精子。但是，大多数研究没有报告基本的临床结局，例如活产，流产和胎儿异常率，这对于确定手术的安全性至关重要。结论本综述提供了有关ICSI程序一些有争议的技术方面的最新知识，以提高其在特定情况下的效力。尽管胚胎学家可能会从本文介绍的方法中受益以改善ICSI结果，但该专业领域仍需要进行大量精心设计的研究，尤其是为了解决有关这些程序安全性的公开问题。