Shiban Ehab, Krieg Sandro M, Obermueller Thomas, Wostrack Maria, Meyer Bernhard, Ringel Florian
Department of Neurosurgery, Technische Universität München, Munich, Germany.
J Neurosurg. 2015 Aug;123(2):301-6. doi: 10.3171/2014.11.JNS141555. Epub 2015 May 15.
Resection of a motor eloquent lesion has become safer because of intraoperative neurophysiological monitoring (IOM). Stimulation of subcortical motor evoked potentials (scMEPs) is increasingly used to optimize patient safety. So far, scMEP stimulation has been performed intermittently during resection of eloquently located lesions. Authors of the present study assessed the possibility of using a resection instrument for continuous stimulation of scMEPs.
An ultrasonic surgical aspirator was attached to an IOM stimulator and was used as a monopolar subcortical stimulation probe. The effect of the aspirator's use at different ultrasound power levels (0%, 25%, 50%, 75%, and 100%) on stimulation intensity was examined in a saline bath. Afterward monopolar stimulation with the surgical aspirator was used during the resection of subcortical lesions in the vicinity of the corticospinal tract in 14 patients in comparison with scMEP stimulation via a standard stimulation electrode. During resection, the stimulation current at which an MEP response was still measurable with subcortical stimulation using the surgical aspirator was compared with the corresponding stimulation current needed using a standard monopolar subcortical stimulation probe at the same location.
The use of ultrasound at different energy levels did result in a slight but irrelevant increase in stimulation energy via the tip of the surgical aspirator in the saline bath. Stimulation of scMEPs using the surgical aspirator or monopolar probe was successful and almost identical in all patients. One patient developed a new permanent neurological deficit. Transient new postoperative paresis was observed in 28% (4 of 14) of cases. Gross-total resection was achieved in 64% (9 of 14) cases and subtotal resection (> 80% of tumor mass) in 35% (5 of 14).
Continuous motor mapping using subcortical stimulation via a surgical aspirator, in comparison with the sequential use of a standard monopolar stimulation probe, is a feasible and safe method without any disadvantages. Compared with the standard probe, the aspirator offers continuous information on the distance to the corticospinal tract.
由于术中神经生理监测（IOM），对运动功能区明确的病变进行切除已变得更加安全。皮层下运动诱发电位（scMEP）刺激越来越多地用于优化患者安全性。到目前为止，scMEP刺激在功能区明确的病变切除过程中一直是间歇性进行的。本研究的作者评估了使用切除器械连续刺激scMEP的可能性。
将超声手术吸引器连接到IOM刺激器上，并用作单极皮层下刺激探头。在盐水中检查了吸引器在不同超声功率水平（0%、25%、50%、75%和100%）下的使用对刺激强度的影响。随后，在14例患者的皮质脊髓束附近进行皮层下病变切除时，使用手术吸引器进行单极刺激，并与通过标准刺激电极进行的scMEP刺激进行比较。在切除过程中，将使用手术吸引器进行皮层下刺激时仍可测量到MEP反应的刺激电流与在同一位置使用标准单极皮层下刺激探头所需的相应刺激电流进行比较。
在盐水中，不同能量水平的超声使用确实导致通过手术吸引器尖端的刺激能量略有增加，但不相关。使用手术吸引器或单极探头刺激scMEP在所有患者中均成功且几乎相同。1例患者出现了新的永久性神经功能缺损。28%（14例中的4例）的病例观察到术后短暂性新的轻瘫。64%（14例中的9例）的病例实现了全切除，35%（14例中的5例）的病例实现了次全切除（>肿瘤质量的80%）。
与顺序使用标准单极刺激探头相比，通过手术吸引器进行皮层下刺激的连续运动图谱绘制是一种可行且安全的方法，没有任何缺点。与标准探头相比，吸引器可提供关于到皮质脊髓束距离的连续信息。
