The spinocerebellar evoked response as an option of monitoring for inferior cerebellar peduncle dysfunction

本研究旨在建立一种新的术中监测小脑下脚功能的方法。由于脊髓小脑背侧束（SCT）位于Inf.C.Ped内，因此，我们研究了用刺激SCT背侧诱发的小脑表面诱发电位评价Inf.C.Ped功能的可能性。电刺激引起单侧股四头肌收缩。在同侧小脑表面和对侧初级感觉皮层记录诱发电位。从同侧小脑半球获得的高度可重复的电位被命名为脊髓小脑诱发电位（SCEP）。SCEP出现一个负峰，潜伏期为11.7 ± 0.3 msec（N11）。短潜伏期体感诱发电位（SSEP）记录于对侧初级感觉皮层，潜伏期为19.1 ± 0.6毫秒。凝血同侧Inf.C.Ped引起SCEP N11消失或明显降低，但不改变SSEP。切断同侧背柱后，SSEP消失，SCEP N11不受影响。电刺激大鼠股四头肌，在小脑半球记录到可重复的SCEP。我们认为SCEP与SSEP不同，SSEP通过背柱上升，它由位于Inf.C.Ped.的背侧SCT传导。我们的研究结果表明，这可能是可能的，以监测在小脑手术患者的Inf.C.Ped。

The aim of this study was to develop a new method for the intraoperativemonitoring of inferior cerebellar peduncle (Inf.C.Ped) function. As the dorsal spinocerebellar tract (SCT) is located in the Inf.C.Ped, we studied the possibility of using the evoked potential elicited by stimulation of the dorsal SCT and recorded from the cerebellar surface to assess the Inf.C.Ped function.The experimental study was performed in rats. Unilateral muscular contractions of quadriceps femoris muscle were elicited by electrical stimulation. The evoked potentials were recorded from the surface of the ipsilateral cerebellum and the contralateral primary sensory cortex. The highly reproducible potentials obtained from the ipsilateral cerebellar hemisphere were named spinocerebellar evoked potentials (SCEP). The SCEP exhibited one negative peak with a latency of 11.7 ± 0.3 msec (N11). Short latency somatosensory evoked potential (SSEP) was recorded from the contralateral primary sensory cortex with a latency of 19.1 ± 0.6 msec. Coagulation of the ipsilateral Inf.C.Ped caused disappearance or marked reduction of the SCEP N11 but it did not change the SSEP. On the other hand, sectioning of the ipsilateral dorsal column resulted in the disappearance of the SSEP but it did not affect the SCEP N11.Reproducible SCEP was recorded from the rat cerebellar hemisphere by electrical stimulation of the quadriceps femoris muscle. We posit that the SCEP differs from the SSEP which ascends via the dorsal column and that it is conducted by the dorsal SCT located in the Inf.C.Ped. Our results suggest that it may be possible to monitor the Inf.C.Ped in patients during cerebellar surgery.