Intraoperative neurophysiological monitoring for intradural extramedullary XXXX : Why not?

@entity1 @entity808 @entity8 @entity424 @entity5 @entity16 @entity1653 @entity3161
BACKGROUND: While intraoperative neurophysiological monitoring (IOM) for @entity5 has become a standard in neurosurgical practice, IOM for intradural extramedullary @entity5 (IDEMs) is still under debate. The aim of this study is to evaluate the role of IOM during surgery for IDEMs. METHODS: From March 2008 to March 2013, 68 @entity1 had microsurgery with IOM for IDEMs (31 @entity808 , 25 @entity1653 , 6 @entity424 of the cauda/filum terminalis, 4 @entity8 ). The IOM included somatosensory evoked potentials (SEPs), motor evoked potentials (MEPs), and - in selected cases - D-waves. Also preoperative and postoperative neurophysiological assessment was performed with SEPs and MEPs. All @entity1 were evaluated at admission and at follow up (minimum 6 months) with the Modified McCormick Scale (mMCs). RESULTS: Three different IOM patterns were observed during surgery: no change in evoked potentials (63 cases), transitory evoked potentials change (3 cases) and loss of evoked potentials (2 cases). In the first setting surgery was never stopped and a @entity5 removal was achieved (no stop surgery group). In 3 cases of transitory evoked potentials change, surgery was temporarily halted but the @entity5 were at the end completely removed (stop and go surgery group). In 2 more @entity1 the loss of evoked potentials led to an incomplete resection (stop surgery group). No @entity1 presented a worsening of the pre-operative clinical conditions (at admission 47 @entity1 presented mMCs 1-2 and 21 @entity1 mMCs 3-5, while at follow up 62 @entity1 are mMCS 1-2 and 6 @entity1 mMCs 3-5). CONCLUSIONS: In our series significant IOM changes occurred in 5 out of 68 @entity1 with IDEMs (7.35%), and it is conceivable that the modification of the surgical strategy - induced by IOM - prevented or mitigated @entity16 in these cases. Vice versa, in 63 @entity1 (92.65%) IOM invariably predicted a good neurological outcome. Furthermore this technique allowed a @entity5 removal in IDEMs placed in difficult locations as @entity3161 or in antero/antero-lateral position (where rotation of spinal cord can be monitored) and even in case of @entity5 adherent to the spinal cord without a clear cleavage plane.
