Brînzeu Andrei, Drogba Landry, Sindou Marc
1Department of Neurosurgery, University of Lyon 1, Lyon, France.
2Department of Neurosciences, Victor Babeş University of Medicine and Pharmacy, Timişoara, Romania; and.
J Neurosurg. 2018 Apr 6;130(2):611-621. doi: 10.3171/2017.8.JNS171222.
The choice of microvascular decompression (MVD), among the several other surgical options, for treating refractory classical trigeminal neuralgia (TN) relies mostly on preoperative imaging, but the degree of reliability of MRI remains a matter of debate. The authors approached the question of predictability of neurovascular conflict (NVC) in a series of 100 protocolized MRI studies from patients with TN who underwent MVD, by reexamination of MR images, blinded to the clinical data and surgical findings, including the side of the neuralgia.
Patients included in the study were those who underwent MVD after surgical indication had been determined based on a protocolized imagery workup (3D high-resolution T2-weighted cisternography centered on the trigeminal nerve, 3D time-of-flight angiography, and 3D gadolinium-enhanced T1-weighted imaging) performed at our institution. All MR images were blindly reexamined, and neurovascular relationships were described on both sides, noting the existence of compression, vessels involved, situation along the root, and degree of compression. The results of MRI evaluation were then compared with actual surgical findings. The extent of agreement and quality of the prediction were expressed with Cohen's kappa coefficient (κ) and receiver operating characteristic (ROC) statistics.
A conflict had actually been found during surgery in 94 of 100 patients. The sensitivity of MRI to detect a conflict was 97% and the specificity was 50%. Vessel type was identified with high reliability (κ = 0.80), while the grade of the conflict and its situation along the root showed poor to average reliability (κ = 0.38 and κ = 0.40, respectively). The area under the ROC curve for predicting the presence of a conflict according to the grades of conflict seen on MRI was 0.93, which is considered very good. The positive predictive value was differentiated according to the grade of conflict, with a very high value for high grades of vascular conflict.
This study shows an overall good reliability of MRI to predict the existence of an NVC. The prediction value is excellent for high grades of compression. Some apparent low-grade compressions on MRI may be revealed as false positives in surgical exploration. This raises the question of what other imaging methods might be used to determine not only the existence of a conflict but also its degree of compression. The degree of compression is of paramount importance to predict the probability of long-term pain relief, and therefore in the decision to propose MVD as the first choice of surgical treatment.
在治疗难治性经典三叉神经痛（TN）的几种手术选择中，微血管减压术（MVD）的选择主要依赖于术前影像学检查，但MRI的可靠程度仍存在争议。作者通过重新检查MR图像，对100例接受MVD的TN患者的一系列标准化MRI研究中的神经血管冲突（NVC）可预测性问题进行了探讨，检查时对临床数据和手术结果（包括神经痛的部位）不知情。
纳入研究的患者是那些在我院根据标准化影像检查（以三叉神经为中心的3D高分辨率T2加权脑池造影、3D时间飞跃血管造影和3D钆增强T1加权成像）确定手术指征后接受MVD的患者。所有MR图像均进行盲法重新检查，并描述双侧神经血管关系，记录压迫的存在、受累血管、沿神经根的情况以及压迫程度。然后将MRI评估结果与实际手术结果进行比较。一致性程度和预测质量用Cohen卡方系数（κ）和受试者操作特征（ROC）统计量表示。
100例患者中有94例在手术中实际发现了冲突。MRI检测冲突的敏感性为97%，特异性为50%。血管类型的识别可靠性较高（κ = 0.80），而冲突程度及其沿神经根的情况显示可靠性较差至中等（分别为κ = 0.38和κ = 0.40）。根据MRI上所见冲突等级预测冲突存在的ROC曲线下面积为0.93，被认为非常好。阳性预测值根据冲突等级有所不同，高等级血管冲突的阳性预测值非常高。
本研究表明MRI预测NVC存在的总体可靠性良好。对于高等级压迫，预测价值极佳。MRI上一些明显的低等级压迫在手术探查中可能显示为假阳性。这就提出了一个问题，即可以使用哪些其他成像方法不仅来确定冲突的存在，还能确定其压迫程度。压迫程度对于预测长期疼痛缓解的可能性至关重要，因此对于决定将MVD作为手术治疗的首选也很重要。
