Department of Otorhinolaryngology, Head & Neck Surgery, Martin Luther University Halle-Wittenberg, University Medicine Halle, Germany.
Oticon Medical AB, Askim, Sweden.
Otol Neurotol. 2021 Feb 1;42(2):278-284. doi: 10.1097/MAO.0000000000002919.
To investigate the minimum bone thickness in adults and children in the area of the skull affected by implantation of a new bone conduction device in patients without known medical history that indicates anatomical malformations.
Retrospective, non-interventional study on computer tomography (CT) scans on file at a university medical center.
A digital model of the new bone conduction implant was virtually implanted in 3D reconstructions of temporal bones based on 197 CT scans, 132 from adults and 65 from children (evenly distributed in five different age groups). The bone thickness was measured in a total of 11 designated positions; five measurement points for the transducer (recess area), and six for the fixation screws, corresponding to three different positions for the fixation band holding the implant in place (screw area).
The minimum bone thickness in the combined recess and screw area for adults was 5.55 ± 1.46 mm, with a 95% CI of 5.30 to 5.80 mm. For children, the thickness was 4.34 ± 2.29 mm (95% CI: 3.77-4.91 mm), increasing from 1.92 mm (0-4 yr) to 6.41 mm (12-14 yr). For all ages, the bone in the recess area was generally thicker compared with the screw area.With an implantation depth of 3 mm the transducer fitted in all of the adult temporal bones (100%) and 99.2% (131/132) of the adults had a bone thickness of at least 2.7 mm in all six measured screw positions. In all children from the age of 5 the transducer fitted at an implantation depth of 3 mm, and in all children from the age of 9, the fixation screws fitted at a depth of 2.7 mm. In all CT scans except for a 6-month-old child the new bone conduction device could be implanted in at least one of the fixation band positions analyzed.
In adults and many children without known medical history that indicates anatomical malformations, the average minimum bone thickness was thicker than both the maximum transducer depth of 3 mm and the 2.7 mm bone involvement of the osseointegrating fixation screws. The results indicate implant fit of the new bone conduction implant in all adult patients. The risks of compromising the sigmoid sinus and the dura as considered with larger implants are thus significantly reduced. Preoperative planning with CT would still be recommended for children below 9 years old.
研究在无已知解剖畸形病史的患者中，新骨导植入物植入部位颅骨的成人和儿童最小骨厚度。
在大学医学中心的档案中进行回顾性、非干预性的计算机断层扫描（CT）研究。
在基于 197 个 CT 扫描的颞骨 3D 重建中，虚拟植入了新骨导植入物的数字模型，其中 132 个来自成人，65 个来自儿童（均匀分布在五个不同的年龄组）。总共在 11 个指定位置测量骨厚度；五个用于换能器（凹槽区域）的测量点，六个用于固定螺钉，对应于固定带固定植入物的三个不同位置（螺钉区域）。
成人的联合凹槽和螺钉区域的最小骨厚度为 5.55 ± 1.46mm，95%置信区间为 5.30 至 5.80mm。对于儿童，厚度为 4.34 ± 2.29mm（95%置信区间：3.77-4.91mm），从 1.92mm（0-4 岁）增加到 6.41mm（12-14 岁）。对于所有年龄组，凹槽区域的骨厚度通常比螺钉区域厚。植入深度为 3mm 时，所有成人颞骨（100%）和 99.2%（131/132）的成人在所有六个测量的螺钉位置均有至少 2.7mm 的骨厚度。在所有 5 岁以上的儿童中，换能器都可以在 3mm 的植入深度下安装，在所有 9 岁以上的儿童中，固定螺钉都可以在 2.7mm 的深度下安装。除了一名 6 个月大的儿童外，所有 CT 扫描都可以在分析的至少一个固定带位置植入新的骨导装置。
在无已知解剖畸形病史的成人和许多儿童中，平均最小骨厚度均大于最大换能器深度 3mm 和骨整合固定螺钉的 2.7mm 骨受累。结果表明，所有成年患者都适合植入新的骨导植入物。因此，与较大植入物相比，对乙状窦和硬脑膜造成损害的风险显著降低。对于 9 岁以下的儿童，仍建议进行术前 CT 规划。
