Essert Caroline, Fernandez-Vidal Sara, Capobianco Antonio, Haegelen Claire, Karachi Carine, Bardinet Eric, Marchal Maud, Jannin Pierre
ICube, Université de Strasbourg/CNRS (UMR 7357), 300 bd Sébastien Brant, BP 10413, 67412, Illkirch, France.
ICM CENIR, CNRS (UMR 7225)/INSERM (U975)/UPMC/Hôpital Pitié-Salpêtrière, 47 boulevard de l'Hôpital, 75013, Paris, France.
Int J Comput Assist Radiol Surg. 2015 Dec;10(12):1973-83. doi: 10.1007/s11548-015-1263-5. Epub 2015 Jul 26.
Automatic methods for preoperative trajectory planning of electrodes in deep brain stimulation are usually based on the search for a path that resolves a set of surgical constraints to propose an optimal trajectory. The relative importance of each surgical constraint is usually defined as weighting parameters that are empirically set beforehand. The objective of this paper is to analyze the use of these parameters thanks to a retrospective study of trajectories manually planned by neurosurgeons. For that purpose, we firstly retrieved weighting factors allowing to match neurosurgeons manually planned choice of trajectory on each retrospective case; secondly, we compared the results from two different hospitals to evaluate their similarity; and thirdly, we compared the trends to the weighting factors empirically set in most current approaches.
To retrieve the weighting factors best matching the neurosurgeons manual plannings, we proposed two approaches: one based on a stochastic sampling of the parameters and the other on an exhaustive search. In each case, we obtained a sample of combinations of weighting parameters with a measure of their quality, i.e., the similarity between the automatic trajectory they lead to and the one manually planned by the surgeon as a reference. Visual and statistical analyses were performed on the number of occurrences and on the rank means.
We performed our study on 56 retrospective cases from two different hospitals. We could observe a trend of the occurrence of each weight on the number of occurrences. We also proved that each weight had a significant influence on the ranking. Additionally, we observed no influence of the medical center parameters, suggesting that the trends were comparable in both hospitals. Finally, the obtained trends were confronted to the usual weights chosen by the community, showing some common points but also some discrepancies.
The results tend to show a predominance of the choice of a trajectory close to a standard direction. Secondly, the avoidance of the vessels or sulci seems to be sought in the surroundings of the standard position. The avoidance of the ventricles seems to be less predominant, but this could be due to the already reasonable distance between the standard direction and the ventricles. The similarity of results between two medical centers tends to show that it is not an exceptional practice. These results suggest that manual planning software may introduce a bias in the planning by proposing a standard position.
深部脑刺激术中电极术前轨迹规划的自动方法通常基于寻找一条解决一组手术约束条件的路径，以提出最佳轨迹。每个手术约束条件的相对重要性通常被定义为事先凭经验设定的加权参数。本文的目的是通过对神经外科医生手动规划的轨迹进行回顾性研究，来分析这些参数的使用情况。为此，我们首先检索了加权因子，以便在每个回顾性病例中匹配神经外科医生手动规划的轨迹选择；其次，我们比较了两家不同医院的结果以评估其相似性；第三，我们将这些趋势与当前大多数方法中凭经验设定的加权因子进行了比较。
为了检索与神经外科医生手动规划最匹配的加权因子，我们提出了两种方法：一种基于参数的随机采样，另一种基于穷举搜索。在每种情况下，我们都获得了一组加权参数组合的样本，并对其质量进行了度量，即它们所导致的自动轨迹与外科医生手动规划的作为参考的轨迹之间的相似性。对出现次数和排名均值进行了视觉和统计分析。
我们对来自两家不同医院的56个回顾性病例进行了研究。我们可以观察到每个权重在出现次数上的一种趋势。我们还证明了每个权重对排名都有显著影响。此外，我们观察到医疗中心参数没有影响，这表明两家医院的趋势具有可比性。最后，将获得的趋势与该领域通常选择的权重进行了对比，显示出一些共同点，但也存在一些差异。
结果倾向于表明选择接近标准方向的轨迹占主导地位。其次，似乎在标准位置周围寻求避开血管或脑沟。避开脑室的情况似乎不太突出，但这可能是由于标准方向与脑室之间已经有合理的距离。两个医疗中心结果的相似性倾向于表明这并非罕见的做法。这些结果表明，手动规划软件通过提出标准位置可能会在规划中引入偏差。
