Cluster of Excellence Hearing4all, Department of Otorhinolaryngology, Hannover Medical School, Hannover, Lower Saxony, Germany.
PLoS One. 2018 Oct 26;13(10):e0206435. doi: 10.1371/journal.pone.0206435. eCollection 2018.
The aim of this study was to identify anatomical indication ranges for different lateral wall cochlear implant electrodes to support surgeons in the preoperative preparation.
272 patients who were implanted with a FLEX20, FLEX24, FLEX28, or a custom-made device (CMD) were included in this study. The cochlear duct length (CDL) and basal cochlear diameter (length A) were measured within preoperative imaging data. The parameter A was then employed to additionally compute CDL estimates using literature approaches. Moreover, the inserted electrode length (IEL) and insertion angle (IA) were measured in postoperative CT data. By combining the preoperative measurements with the IA data, the covered cochlea length (CCL) and relative cochlear coverage (CC) were determined for each cochlea.
The measurements of the CDL show comparable results to previous studies. While CDL measurements and estimations cover similar ranges overall, severe deviations occur in individual cases. The electrode specific IEL and CCL are fairly consistent and increase with longer electrodes, but relatively wide ranges of electrode specific CC values were found due to the additional dependence on the respective CDL. Using the correlation of IEL and CCL across electrode arrays, CDL ranges for selected arrays were developed (FLEX24: 31.3-34.4, FLEX28: 36.2-40.1, FLEXSoft: 40.6-44.9).
Our analysis shows that electrode specific CC varies due to the CDL variation. Preoperative measurement of the CDL allows for an individualized implant length selection yielding optimized stimulation and a reduced risk of intraoperative trauma. The CDL, as derived from preoperative CT imaging studies, can help the implant surgeon select the appropriate electrode array to maximize the patient's outcomes.
本研究旨在确定不同侧墙耳蜗植入电极的解剖学适应证范围，以帮助外科医生做好术前准备。
本研究纳入了 272 例接受 FLEX20、FLEX24、FLEX28 或定制设备（CMD）植入的患者。在术前影像学数据中测量耳蜗管长度（CDL）和基底耳蜗直径（长度 A）。然后使用文献方法，通过参数 A 进一步计算 CDL 估计值。此外，在术后 CT 数据中测量插入电极长度（IEL）和插入角度（IA）。通过将术前测量值与 IA 数据相结合，确定每只耳蜗的覆盖耳蜗长度（CCL）和相对耳蜗覆盖率（CC）。
CDL 的测量结果与先前的研究相似。虽然 CDL 测量值和估计值总体上覆盖相似的范围，但在个别情况下会出现严重偏差。特定电极的 IEL 和 CCL 相当一致，并且随着电极长度的增加而增加，但由于对各自 CDL 的额外依赖，发现相对较宽的电极特定 CC 值范围。通过对电极数组中 IEL 和 CCL 的相关性进行分析，开发了选定数组的 CDL 范围（FLEX24：31.3-34.4，FLEX28：36.2-40.1，FLEXSoft：40.6-44.9）。
我们的分析表明，由于 CDL 变化，特定电极的 CC 会发生变化。术前 CDL 的测量可以实现个体化的植入长度选择，从而优化刺激效果，并降低术中创伤的风险。术前 CT 成像研究中获得的 CDL 可帮助植入外科医生选择合适的电极数组，从而最大限度地提高患者的治疗效果。
