If video learn to diagnose failure , nerve otology doctor must consider an operation to probe 若影像学诊断失败，神经耳科医师必须考虑手术探查。
3.
Part 4 makes the efforts on the study of the effectiveness and the practicability of the erssma by the use of the skills of semicircular resection of the modern otology 第四部分将现代神经耳科保留听力的半规管切除技术和乙状窦后经内耳孔上入路相结合，研究扩大经内耳孔上入路的实用性和有效性。
4.
There had n ' t a report about the study on the microsurgical anatomy of this approach in our country and there were rarely found in the data overseas . the development of the neuro - otology has made it possible for the resection of the semicircular with the preservation of hearing . by the use of this skill , the removal range of the petrosal bone could be enlarged . this is called the expanding retrosigmoid approach 在保留听力的条件下将现代神经耳科学的半规管切除新技术和乙状窦后经内耳孔上入路结合起来，将使该手术入路得到扩展，这就是扩大乙状窦后经内耳孔上入路( erssma ) ，对它的显微外科解剖学研究，国内外来见报道。
