Department of Mechanical Engineering.
Division of Otolaryngology, Department of Surgery, University of Utah, Salt Lake City, Utah.
Otol Neurotol. 2021 Oct 1;42(9):e1219-e1226. doi: 10.1097/MAO.0000000000003250.
The pose (i.e., position and orientation) of a guinea-pig cochlea can be accurately estimated using externally observable features, without requiring computed-tomography (CT) scans.
Guinea pigs are frequently used in otologic research as animal models of cochlear-implant surgery. In robot-assisted surgical insertion of cochlear-implant electrode arrays, knowing the cochlea pose is required. A preoperative CT scan of the guinea-pig anatomy can be labeled and registered to the surgical system, however, this process can be expensive and time consuming.
Anatomical features from both sides of 11 guinea-pig CT scans were labeled and registered, forming sets. Using a groupwise point-set registration algorithm, errors in cochlea position and modiolar-axis orientation were estimated for 11 iterations of registration where each feature set was used as a hold-out set containing a reduced number of features that could all be touched by a motion-tracking probe intraoperatively. The method was validated on 2000 simulated guinea-pig cochleae and six physical guinea-pig-skull cochleae.
Validation on simulated cochleae resulted in cochlea-position estimates with a maximum error of 0.43 mm and modiolar-axis orientation estimates with a maximum error of 8.1 degrees for 96.7% of cochleae. Physical validation resulted in cochlea-position estimates with a maximum error of 0.80 mm and modiolar-axis orientation estimates with a maximum error of 12.4 degrees.
This work enables researchers conducting robot-assisted surgical insertions of cochlear-implant electrode arrays using a guinea-pig animal model to estimate the pose of a guinea-pig cochlea by locating six externally observable features on the guinea pig, without the need for CT scans.
可以使用外部可观察的特征准确估计豚鼠耳蜗的姿势（即位置和方向），而无需进行计算机断层扫描（CT）扫描。
豚鼠经常作为耳蜗植入手术的动物模型在耳科学研究中使用。在机器人辅助的耳蜗植入电极阵列手术插入中，需要知道耳蜗的位置。可以对豚鼠解剖结构的术前 CT 扫描进行标记和注册到手术系统，但是，此过程可能昂贵且耗时。
对 11 只豚鼠 CT 扫描的两侧的解剖特征进行标记和注册，形成集合。使用群组点集配准算法，对 11 次配准迭代中的耳蜗位置和蜗轴方向误差进行了估计，其中每次配准集合都用作包含通过手术中运动跟踪探针可触及的减少数量的特征的保留集。该方法在 2000 个模拟豚鼠耳蜗和 6 个物理豚鼠颅骨耳蜗上进行了验证。
在模拟耳蜗上的验证结果表明，对于 96.7％的耳蜗，耳蜗位置估计的最大误差为 0.43 毫米，蜗轴方向估计的最大误差为 8.1 度。物理验证的结果表明，耳蜗位置估计的最大误差为 0.80 毫米，蜗轴方向估计的最大误差为 12.4 度。
这项工作使使用豚鼠动物模型进行机器人辅助耳蜗植入电极阵列手术的研究人员能够通过在豚鼠上定位六个外部可观察的特征来估计豚鼠耳蜗的位置，而无需进行 CT 扫描。
