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O2-E-60. Usefulness of pharyngeal motor evoked potential monitoring during skull base tumor surgery
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Society Proceedings / Clinical Neurophysiology 124 (2013) e19–e38
O2-E-44. Pathology of C5 palsy after cervical laminoplasty using electrophysiological investigation and MRI—Yasuaki Imajo, Tsukasa Kanchiku, Masahiro Funaba, Toshihiko Taguchi (Yamaguchi University, Yamaguchi, Japan) This retrospective study investigated 4 patients with C5 palsy following cervical laminoplasty. Our aim was to understand the underlying pathology after conducting electrophysiological investigations and MRI before and after surgery. Erb-point-stimulated CMAPs were recorded in deltoid and biceps. We hypothesized that more than 3 mV reduction of CMAPs and prolongation of onset latency longer than 0.5 ms on the affected side indicated C5 radiculopathy in deltoid and C6 radiculopathy in biceps, respectively. C5 radiculopathy was indicated in one patient and C6 radiculopathy in another. C5 and C6 segmental cord was involved in the third patient and C6 segmental cord in the fourth. Spinal cord evoked potentials were recorded intraoperatively. The C3/4 level only was affected in two, both the C4/5 and C5/6 levels in another and both the C3/4 and C4/5 levels in the fourth patient. When C5 or C6 radiculopathy occurs after laminoplasty, C5 palsy may become clinically apparent because the deltoid is predominantly innervated by C5 root due to spinal cord damage of C6 segment in C4/5 before surgery, and by C6 root due to spinal cord damage of C5 segment in C3/4, respectively. The posterior shift of the spinal cord estimated by MRI was large when radiculopathy occurred. doi:10.1016/j.clinph.2013.02.083
O2-E-46. Common peroneal nerve palsy with fibula head fracture: Case report—Kazuaki Sonofuchi, Shingo Nobuta, Taku Hatta, Katsumi Sato, Eiji Itoi (Tohoku University School of Medicine, Sendai, Japan) Common peroneal nerve palsy at the knee level is one of the most common peripheral neuropathy. The involvement is mainly caused by the compression or traction of the nerve. Clinically, however, the palsy associated with isolated fibula head fracture is uncommon. We present a case of these combined injuries treated operatively. A 51-year-old male was involved by a fall. X-ray revealed an avulsion fracture of the fibula head, and MRI revealed intact ligamentous structures at the knee joint. The nerve conduction study showed the peroneal nerve palsy at the fibula head level. Fourteen days after the injury, surgical treatment for internal fixation of fibula head fracture and external neurolysis of common peroneal nerve was performed. Common peroneal nerve showed continuity, with the bleeding in epineurium both at the fracture level and at the level 5 cm proximally. In this case, common peroneal nerve was involved by compression due to the fibula head fragment as well as traction force. doi:10.1016/j.clinph.2013.02.084
O2-E-48. Control of Br (E)-MsEP used in the intraoperative spinal cord monitoring during the surgery of cervical spine—Seiji Kanno, Muneharu Ando, Tetsuya Tamaki, Yasushi Toge (Wakayama Rosak Hospital, Wakayama, Japan) Brain-evoked muscle-action potential (Br (E)-MsEP) is useful method of the intraoperative spinal cord monitoring. In the intraoperative monitoring during spinal surgery, in the influence of anesthetizing and other general conditions should be considered. Although we usually monitor the muscle of the upper extremity as the reference waveform in thoracic and lumber spine surgery, there is no reference waveform in cervical spine surgery. The aim of this study was
to evaluation of utility of the electromyogram of sternocleidomastoideus (SCM) and diaphragm (DP) as the reference waveform in the intraoperative monitoring using Br (E)-MsEP. In ten patients during spinal surgery, we monitor the electromyogram of SCM and DP. In all patients, the electromyograms of SCM and DP were able to be recorded but we could not detect onset point of SCM at all due to interference of stimulation waveform. On the other hand, the onset latencies of DP were 17.8 ± 1.9 (mean ± SD) ms. The peak-to-peak amplitudes of SCM and DP were 607.5 ± 329.3 lV and 366.2 ± 264.1 (mean ± SD) lV respectively. Our findings suggest that DP may become a reference waveform of the intraoperative monitoring during cervical spine surgery. doi:10.1016/j.clinph.2013.02.085
O2-E-60. Usefulness of pharyngeal motor evoked potential monitoring during skull base tumor surgery—Masafumi Fukuda, Makoto Oishi, Tetsuya Hiraishi, Tetsuro Takao, Yukihiko Fujii (Department of Neurosurgery, Niigata University, Niigata, Japan) The aim of this study was to determine whether monitoring of pharyngeal motor evoked potentials (PhMEPs) elicited by transcranial electrical stimulation during skull base tumor surgery might be useful for predicting postoperative swallowing deterioration. The authors analyzed PhMEPs in 27 patients during 28 surgical procedures for the treatment of skull base tumors. Corkscrew electrodes positioned at C3 or C4 and Cz were used to deliver supra-maximal stimuli. PhMEPs were recorded from the posterior wall of the pharynx through a modified endotracheal tube. Postoperative swallowing function was significantly correlated with the final/baseline PhMEP ratio (r = 0.55, p < 0.005). A PhMEP ratio <50% was recorded during 8 of 28 procedures; in 7 (88%) of these cases, the patients experienced postoperative deterioration of swallowing function. After 20 procedures, the PhMEP ratios remained >50%. In 16 (80%) of these 20 procedures, the patients showed no changes of swallowing function postoperatively (p < 0.005). Intraoperative PhMEP monitoring can be useful for predicting swallowing deterioration following skull base tumor surgery, especially in patients with swallowing disturbances that are mainly due to reduction in the motor functions of the pharyngeal muscles. doi:10.1016/j.clinph.2013.02.086
O2-E-61. Correlation between postoperative facial nerve function and neurophysiological examinations in the perioperative period for vestibular schwannoma—Hiraishi Tetsuya, Masafumi Fukuda, Makoto Oishi, Tetsuro Takao, Yukihiko Fujii (Brain Research Institute, Niigata University, Niigata, Japan) The aim of this study was to examine the correlation between a change of blink reflex (BR) and facial motor evoked potential (FMEP) before and after the vestibular schwannoma (VS) operation and the postoperative facial nerve function (FNF). The study involved 53 patients who were operated for VS. Postoperative FNF was assessed at 1 and 12 months after operation according to House and Blackmann grade. BR was recorded before and after operation within two weeks. Ipsilateral and contralateral differences in latency were defined as DR1. DR1 is classified by the following range (DR1 q2ms, 2 < DR1 q4ms, 4 ms < DR1, not detectable). FMEPs were recorded from the orbicularis oculi and oris muscles. The correlation between DR1, the final-to-baseline FMEP ratio, and postoperative FNF were examined. Postoperative FNF correlated significantly with the postoperativeDR1 grades at 1 and 12 months after operation (p < 0.001, respectively). Postoperative FNF corre-
Society Proceedings / Clinical Neurophysiology 124 (2013) e19–e38
O2-E-44. Pathology of C5 palsy after cervical laminoplasty using electrophysiological investigation and MRI—Yasuaki Imajo, Tsukasa Kanchiku, Masahiro Funaba, Toshihiko Taguchi (Yamaguchi University, Yamaguchi, Japan) This retrospective study investigated 4 patients with C5 palsy following cervical laminoplasty. Our aim was to understand the underlying pathology after conducting electrophysiological investigations and MRI before and after surgery. Erb-point-stimulated CMAPs were recorded in deltoid and biceps. We hypothesized that more than 3 mV reduction of CMAPs and prolongation of onset latency longer than 0.5 ms on the affected side indicated C5 radiculopathy in deltoid and C6 radiculopathy in biceps, respectively. C5 radiculopathy was indicated in one patient and C6 radiculopathy in another. C5 and C6 segmental cord was involved in the third patient and C6 segmental cord in the fourth. Spinal cord evoked potentials were recorded intraoperatively. The C3/4 level only was affected in two, both the C4/5 and C5/6 levels in another and both the C3/4 and C4/5 levels in the fourth patient. When C5 or C6 radiculopathy occurs after laminoplasty, C5 palsy may become clinically apparent because the deltoid is predominantly innervated by C5 root due to spinal cord damage of C6 segment in C4/5 before surgery, and by C6 root due to spinal cord damage of C5 segment in C3/4, respectively. The posterior shift of the spinal cord estimated by MRI was large when radiculopathy occurred. doi:10.1016/j.clinph.2013.02.083
O2-E-46. Common peroneal nerve palsy with fibula head fracture: Case report—Kazuaki Sonofuchi, Shingo Nobuta, Taku Hatta, Katsumi Sato, Eiji Itoi (Tohoku University School of Medicine, Sendai, Japan) Common peroneal nerve palsy at the knee level is one of the most common peripheral neuropathy. The involvement is mainly caused by the compression or traction of the nerve. Clinically, however, the palsy associated with isolated fibula head fracture is uncommon. We present a case of these combined injuries treated operatively. A 51-year-old male was involved by a fall. X-ray revealed an avulsion fracture of the fibula head, and MRI revealed intact ligamentous structures at the knee joint. The nerve conduction study showed the peroneal nerve palsy at the fibula head level. Fourteen days after the injury, surgical treatment for internal fixation of fibula head fracture and external neurolysis of common peroneal nerve was performed. Common peroneal nerve showed continuity, with the bleeding in epineurium both at the fracture level and at the level 5 cm proximally. In this case, common peroneal nerve was involved by compression due to the fibula head fragment as well as traction force. doi:10.1016/j.clinph.2013.02.084
O2-E-48. Control of Br (E)-MsEP used in the intraoperative spinal cord monitoring during the surgery of cervical spine—Seiji Kanno, Muneharu Ando, Tetsuya Tamaki, Yasushi Toge (Wakayama Rosak Hospital, Wakayama, Japan) Brain-evoked muscle-action potential (Br (E)-MsEP) is useful method of the intraoperative spinal cord monitoring. In the intraoperative monitoring during spinal surgery, in the influence of anesthetizing and other general conditions should be considered. Although we usually monitor the muscle of the upper extremity as the reference waveform in thoracic and lumber spine surgery, there is no reference waveform in cervical spine surgery. The aim of this study was
to evaluation of utility of the electromyogram of sternocleidomastoideus (SCM) and diaphragm (DP) as the reference waveform in the intraoperative monitoring using Br (E)-MsEP. In ten patients during spinal surgery, we monitor the electromyogram of SCM and DP. In all patients, the electromyograms of SCM and DP were able to be recorded but we could not detect onset point of SCM at all due to interference of stimulation waveform. On the other hand, the onset latencies of DP were 17.8 ± 1.9 (mean ± SD) ms. The peak-to-peak amplitudes of SCM and DP were 607.5 ± 329.3 lV and 366.2 ± 264.1 (mean ± SD) lV respectively. Our findings suggest that DP may become a reference waveform of the intraoperative monitoring during cervical spine surgery. doi:10.1016/j.clinph.2013.02.085
O2-E-60. Usefulness of pharyngeal motor evoked potential monitoring during skull base tumor surgery—Masafumi Fukuda, Makoto Oishi, Tetsuya Hiraishi, Tetsuro Takao, Yukihiko Fujii (Department of Neurosurgery, Niigata University, Niigata, Japan) The aim of this study was to determine whether monitoring of pharyngeal motor evoked potentials (PhMEPs) elicited by transcranial electrical stimulation during skull base tumor surgery might be useful for predicting postoperative swallowing deterioration. The authors analyzed PhMEPs in 27 patients during 28 surgical procedures for the treatment of skull base tumors. Corkscrew electrodes positioned at C3 or C4 and Cz were used to deliver supra-maximal stimuli. PhMEPs were recorded from the posterior wall of the pharynx through a modified endotracheal tube. Postoperative swallowing function was significantly correlated with the final/baseline PhMEP ratio (r = 0.55, p < 0.005). A PhMEP ratio <50% was recorded during 8 of 28 procedures; in 7 (88%) of these cases, the patients experienced postoperative deterioration of swallowing function. After 20 procedures, the PhMEP ratios remained >50%. In 16 (80%) of these 20 procedures, the patients showed no changes of swallowing function postoperatively (p < 0.005). Intraoperative PhMEP monitoring can be useful for predicting swallowing deterioration following skull base tumor surgery, especially in patients with swallowing disturbances that are mainly due to reduction in the motor functions of the pharyngeal muscles. doi:10.1016/j.clinph.2013.02.086
O2-E-61. Correlation between postoperative facial nerve function and neurophysiological examinations in the perioperative period for vestibular schwannoma—Hiraishi Tetsuya, Masafumi Fukuda, Makoto Oishi, Tetsuro Takao, Yukihiko Fujii (Brain Research Institute, Niigata University, Niigata, Japan) The aim of this study was to examine the correlation between a change of blink reflex (BR) and facial motor evoked potential (FMEP) before and after the vestibular schwannoma (VS) operation and the postoperative facial nerve function (FNF). The study involved 53 patients who were operated for VS. Postoperative FNF was assessed at 1 and 12 months after operation according to House and Blackmann grade. BR was recorded before and after operation within two weeks. Ipsilateral and contralateral differences in latency were defined as DR1. DR1 is classified by the following range (DR1 q2ms, 2 < DR1 q4ms, 4 ms < DR1, not detectable). FMEPs were recorded from the orbicularis oculi and oris muscles. The correlation between DR1, the final-to-baseline FMEP ratio, and postoperative FNF were examined. Postoperative FNF correlated significantly with the postoperativeDR1 grades at 1 and 12 months after operation (p < 0.001, respectively). Postoperative FNF corre-