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P11.1 Peripheral nervous system maturation in very preterm infant: serial nerve conduction studies
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Poster presentations: Poster session 11. Neuromonitoring
Methods: We compare recordings from the tibialis anterior, brachoradialis and biceps brachii muscles given their possibly differing characteristics and involvement in muscle disorders. VRCs were measured by direct muscle stimulation and recording with 1, 2 and 5 conditioning stimuli (10 ms apart) delivered at intervals from 2 1000 ms prior to test stimulus. Results: The maximum increase in velocity (supernormality-SN10) differed between the three muscles, being ~11% in tibialis anterior, ~13% in brachoradialis and ~15% in biceps brachii. This was seen at an interstimulus interval of 10 ms or less and was constant in amplitude with 1, 2 or 5 conditioning stimuli. A second phase of supernormality seen at approximately 100 ms (SN100), in contrast to the SN10, increased in amplitude with the number of conditioning stimuli. The variance between muscles may reflect differing fibre or ion channel characteristics. Conclusions: VRCs are relatively quick to perform, should give new insights into muscle disorder pathophysiology and may become a helpful clinical tool. Reference(s) [1] Allen D, Arunachalam R, Mills K. Muscle & Nerve 37: 14 22, 2008 [2] Z’Graggen WJ, Bostock H. Muscle & Nerve 39: 616 626, 2009
Poster session 11. Neuromonitoring
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P11.1 Peripheral nervous system maturation in very preterm infant: serial nerve conduction studies E. Molesti1 , G. Bertini2 , D. Gualandi1 , C. Dani2 , M.E. Bastianelli1 , S. Gabbanini1 , R. Carrai1 , A. Grippo1 , A. Amantini1 , F. Pinto1 , S. Lori1 1 Department of Neuroscience, Neurophysiology Unit, University of Florence, Florence, Italy, 2 Department of Maternal-Childish, Neonatology Intensive Care, University of Florence, Florence, Italy Introduction: In last years, the progress made in neonatal care, have led to a higher survival rate and better treatment results in the Extremely Low Gestational Age (ELGA) preterm. Sufficient reference values of nerve conduction studies (NCS) in this population are limited. The last important study has been published by Smit more than 10 years ago. Objective: To study the maturation of sensory-motor (S-M) NCS of median, medial plantar, ulnar and posterior tibial nerves with serial recordings in ELGA and LGA preterm and to provide the reference values in this population. Material and Methods: We performed the S-M NCS in 26 neurologically normal preterm babies, range 23 33 weeks of Gestational Age (GA) (11M15F; weight range 580 1910 gr) in the first week of life. 15 of them were studied also at term corrected age (TCA), and in 8 babies the S-M NCS were conducted every two weeks until TCA. Cross-sectional and longitudinal values of S-M NCS of median, medial plantar, ulnar and tibial nerves were analyzed in relation of Post-Mestrual-Age (PMA) and matched with those measured in a group of 10 Full-Term (FT) babies. Statistical Analisys: ANOVA, Linear and Multivariate Regression. Results: The range of values related to GA (23 33 w) was 7.5 20.8 m/s and 11 25.2 m/s for tibial and ulnar M-NCS, 8.4 22.5 m/s and 9.4 19.6 m/s for S-NCS of medial plantar and median, respectively. S-M NCS values increased significantly in relation to PMA (P < 0.005), especially between 24th and 28th week, up to 300%. Not significant difference was found between S-M NCS TCA and FT babies. Conclusion: Our study showed that S-M NCS was clearly related to PMA and extrauterine life does not affect the maturation of Peripheral Nervous System in neurologically normal very preterm babies, even in ELGA for whom there are very few data in literature. P11.2 Joint use of short- and long-latency evoked potentials and EEG reactivity for coma prognosis in a non-university hospital L. Garcia-Larrea1 , E. Hofmann1 , C. Buisson1 , M. Duclaux1 , O. Reynier1 , D. Savarino1 1 Explorations neurosensorielles, Hˆ opital de Valence (Drˆ ome), France The assessment of coma prognosis with short-latency EPs is now part of routine neurophysiological examination in most university hospitals. The combined study of short- and long-latency responses and its combination with EEG is more recent and remains restricted to a few university hospitals. Here we review the results obtained in 50 consecutive
1
comatose patients (66% anoxic, 28% traumatic, 6% other) studied with short- and long-latency EPs combined with EEG reactivity in a nonuniversity hospital. Were assessed (i) the auditory I-V interval, Na-Pa complex and N100 vertex potential; (ii) the somatosensory N9, P14 and N20 responses, and (iii) the EEG reactivity to auditory and somatic stimuli. Short-latency EPs and EEG were obtained at least once in every patient; the N100 was recorded when short-latency EPs were present. Results confirm the ominous prognosis associated with bilateral absence of cortical responses N20 and Pa, and a fortiori of brainstem responses, whatever the coma etiology. Preservation of such responses does not have a positive predictive value, and was followed by death or PVS in one third of cases. Preservation of both short- and long-latency responses (N20+Pa+N100) had a strong positive predictive value for awakening from coma, but only if they were associated with a reactive EEG. N100 and EEG reactivity were strongly associated, and their dissociation (N100 but non reactive EEG) was followed in 3 cases by a minimally conscious state (MCS). Unilateral suppression of somatosensory N20, with preservation of all other responses was associated with sensorimotor handicap on awakening. This study demonstrates again the prognostic usefulness of neurophysiological assessment of coma, and shows its feasibility in a non-universitary context. The positive predictive value of EPs may be strongly improved by adding a simple evaluation of EEG reactivity. Quantifying the EEG reactivity using simple measures of spectral analysis might significantly improve its predictive value, and even replace more sophisticated and difficult-to-implement measures such as MMN or P300. Although EEG interpretation is hampered by sedative drugs, the same can be applied to long-latency and cognitive-driven evoked potentials. P11.3 Role of intraoperative neurophysiological monitoring in predicting clinical outcome of supratentorial brain tumors resection S. Contardi1 , A. Mantovani2 , F. Antonelli1 , G. Pinna2 , P. Nichelli1 , F. Valzania1 1 Department of Neuroscience, Neurology Clinic, University of Modena and Reggio Emilia, St. Agostino-Estense Hospital, Modena, Italy, 2 Department of Neuroscience, Neurosurgery Division, University of Modena and Reggio Emilia, St. Agostino-Estense Hospital, Modena, Italy Introduction: Neurosurgery for brain tumors inside or next to motor cortex requires cortical mapping to locate motor functions and direct electrical stimulation to preserve motor functions. Objectives: We evaluated the effects of intraoperative neurophysiological monitoring (IOM) during supratentorial surgery on postoperative morbidity. Methods: Twenty-nine patients were included in the study. We firstly identified central sulcus by means of somatosensory evoked potential phase reversal technique; then we used direct cortical multipulse stimulation to map motor area. During tumour removal we monitored motor pathways using muscle motor evoked potentials (mMEPs) elicited by transcranial electrical stimulation (TES) or by direct stimulation of motor cortex (DCS). We reported intraoperative findings of primary motor cortex, motor outcome at short- (1 week) and long-term (3 12 months) follow-up. Results: All patients exhibited recordable baseline mMEPs. During tumour removal 8 patients (27%) presented mild amplitude reduction and 2 patients (7%) disappearance of mMEPs. Using corrective measures, intraoperative changes of mMEPs were reversed in the first 8 patients, whereas in the other 2 we confirmed the lost of mMEPs at the end of surgery. New immediate postoperative motor deficits were documented in 13 patients (44%); permanent deficits were observed in 5 subjects (17%), due to intraoperatory ictal events or delayed hematomas in 3 of them. In the other 2 patients, the first one didn’t show mMEPs changes and reported a worsening of preoperative emiparesis; the second one presented a mMEPs amplitude reduction not completely reversed by corrective measures and reported a mild hand paresis. Magnetic resonance controls showed a complete or subtotal (>80%) removal of lesion in 27 patients (93%) and a partial resection in 2 subjects. Conclusions: According to literature, our data confirm that a severe drop or a disappearance of mMEPs amplitude at the end of surgery has a higher possibility to present permanent deficits. We also confirm that a low percentage of patients could report the absence of deficits in spite of mMEPs deterioration or, vice versa, some degree of motor deficits in spite of preserved mMEPs. IOM improved our surgical results and minimized the risk of permanent severe neurological deficits.
Poster presentations: Poster session 11. Neuromonitoring
Methods: We compare recordings from the tibialis anterior, brachoradialis and biceps brachii muscles given their possibly differing characteristics and involvement in muscle disorders. VRCs were measured by direct muscle stimulation and recording with 1, 2 and 5 conditioning stimuli (10 ms apart) delivered at intervals from 2 1000 ms prior to test stimulus. Results: The maximum increase in velocity (supernormality-SN10) differed between the three muscles, being ~11% in tibialis anterior, ~13% in brachoradialis and ~15% in biceps brachii. This was seen at an interstimulus interval of 10 ms or less and was constant in amplitude with 1, 2 or 5 conditioning stimuli. A second phase of supernormality seen at approximately 100 ms (SN100), in contrast to the SN10, increased in amplitude with the number of conditioning stimuli. The variance between muscles may reflect differing fibre or ion channel characteristics. Conclusions: VRCs are relatively quick to perform, should give new insights into muscle disorder pathophysiology and may become a helpful clinical tool. Reference(s) [1] Allen D, Arunachalam R, Mills K. Muscle & Nerve 37: 14 22, 2008 [2] Z’Graggen WJ, Bostock H. Muscle & Nerve 39: 616 626, 2009
Poster session 11. Neuromonitoring
1
P11.1 Peripheral nervous system maturation in very preterm infant: serial nerve conduction studies E. Molesti1 , G. Bertini2 , D. Gualandi1 , C. Dani2 , M.E. Bastianelli1 , S. Gabbanini1 , R. Carrai1 , A. Grippo1 , A. Amantini1 , F. Pinto1 , S. Lori1 1 Department of Neuroscience, Neurophysiology Unit, University of Florence, Florence, Italy, 2 Department of Maternal-Childish, Neonatology Intensive Care, University of Florence, Florence, Italy Introduction: In last years, the progress made in neonatal care, have led to a higher survival rate and better treatment results in the Extremely Low Gestational Age (ELGA) preterm. Sufficient reference values of nerve conduction studies (NCS) in this population are limited. The last important study has been published by Smit more than 10 years ago. Objective: To study the maturation of sensory-motor (S-M) NCS of median, medial plantar, ulnar and posterior tibial nerves with serial recordings in ELGA and LGA preterm and to provide the reference values in this population. Material and Methods: We performed the S-M NCS in 26 neurologically normal preterm babies, range 23 33 weeks of Gestational Age (GA) (11M15F; weight range 580 1910 gr) in the first week of life. 15 of them were studied also at term corrected age (TCA), and in 8 babies the S-M NCS were conducted every two weeks until TCA. Cross-sectional and longitudinal values of S-M NCS of median, medial plantar, ulnar and tibial nerves were analyzed in relation of Post-Mestrual-Age (PMA) and matched with those measured in a group of 10 Full-Term (FT) babies. Statistical Analisys: ANOVA, Linear and Multivariate Regression. Results: The range of values related to GA (23 33 w) was 7.5 20.8 m/s and 11 25.2 m/s for tibial and ulnar M-NCS, 8.4 22.5 m/s and 9.4 19.6 m/s for S-NCS of medial plantar and median, respectively. S-M NCS values increased significantly in relation to PMA (P < 0.005), especially between 24th and 28th week, up to 300%. Not significant difference was found between S-M NCS TCA and FT babies. Conclusion: Our study showed that S-M NCS was clearly related to PMA and extrauterine life does not affect the maturation of Peripheral Nervous System in neurologically normal very preterm babies, even in ELGA for whom there are very few data in literature. P11.2 Joint use of short- and long-latency evoked potentials and EEG reactivity for coma prognosis in a non-university hospital L. Garcia-Larrea1 , E. Hofmann1 , C. Buisson1 , M. Duclaux1 , O. Reynier1 , D. Savarino1 1 Explorations neurosensorielles, Hˆ opital de Valence (Drˆ ome), France The assessment of coma prognosis with short-latency EPs is now part of routine neurophysiological examination in most university hospitals. The combined study of short- and long-latency responses and its combination with EEG is more recent and remains restricted to a few university hospitals. Here we review the results obtained in 50 consecutive
1
comatose patients (66% anoxic, 28% traumatic, 6% other) studied with short- and long-latency EPs combined with EEG reactivity in a nonuniversity hospital. Were assessed (i) the auditory I-V interval, Na-Pa complex and N100 vertex potential; (ii) the somatosensory N9, P14 and N20 responses, and (iii) the EEG reactivity to auditory and somatic stimuli. Short-latency EPs and EEG were obtained at least once in every patient; the N100 was recorded when short-latency EPs were present. Results confirm the ominous prognosis associated with bilateral absence of cortical responses N20 and Pa, and a fortiori of brainstem responses, whatever the coma etiology. Preservation of such responses does not have a positive predictive value, and was followed by death or PVS in one third of cases. Preservation of both short- and long-latency responses (N20+Pa+N100) had a strong positive predictive value for awakening from coma, but only if they were associated with a reactive EEG. N100 and EEG reactivity were strongly associated, and their dissociation (N100 but non reactive EEG) was followed in 3 cases by a minimally conscious state (MCS). Unilateral suppression of somatosensory N20, with preservation of all other responses was associated with sensorimotor handicap on awakening. This study demonstrates again the prognostic usefulness of neurophysiological assessment of coma, and shows its feasibility in a non-universitary context. The positive predictive value of EPs may be strongly improved by adding a simple evaluation of EEG reactivity. Quantifying the EEG reactivity using simple measures of spectral analysis might significantly improve its predictive value, and even replace more sophisticated and difficult-to-implement measures such as MMN or P300. Although EEG interpretation is hampered by sedative drugs, the same can be applied to long-latency and cognitive-driven evoked potentials. P11.3 Role of intraoperative neurophysiological monitoring in predicting clinical outcome of supratentorial brain tumors resection S. Contardi1 , A. Mantovani2 , F. Antonelli1 , G. Pinna2 , P. Nichelli1 , F. Valzania1 1 Department of Neuroscience, Neurology Clinic, University of Modena and Reggio Emilia, St. Agostino-Estense Hospital, Modena, Italy, 2 Department of Neuroscience, Neurosurgery Division, University of Modena and Reggio Emilia, St. Agostino-Estense Hospital, Modena, Italy Introduction: Neurosurgery for brain tumors inside or next to motor cortex requires cortical mapping to locate motor functions and direct electrical stimulation to preserve motor functions. Objectives: We evaluated the effects of intraoperative neurophysiological monitoring (IOM) during supratentorial surgery on postoperative morbidity. Methods: Twenty-nine patients were included in the study. We firstly identified central sulcus by means of somatosensory evoked potential phase reversal technique; then we used direct cortical multipulse stimulation to map motor area. During tumour removal we monitored motor pathways using muscle motor evoked potentials (mMEPs) elicited by transcranial electrical stimulation (TES) or by direct stimulation of motor cortex (DCS). We reported intraoperative findings of primary motor cortex, motor outcome at short- (1 week) and long-term (3 12 months) follow-up. Results: All patients exhibited recordable baseline mMEPs. During tumour removal 8 patients (27%) presented mild amplitude reduction and 2 patients (7%) disappearance of mMEPs. Using corrective measures, intraoperative changes of mMEPs were reversed in the first 8 patients, whereas in the other 2 we confirmed the lost of mMEPs at the end of surgery. New immediate postoperative motor deficits were documented in 13 patients (44%); permanent deficits were observed in 5 subjects (17%), due to intraoperatory ictal events or delayed hematomas in 3 of them. In the other 2 patients, the first one didn’t show mMEPs changes and reported a worsening of preoperative emiparesis; the second one presented a mMEPs amplitude reduction not completely reversed by corrective measures and reported a mild hand paresis. Magnetic resonance controls showed a complete or subtotal (>80%) removal of lesion in 27 patients (93%) and a partial resection in 2 subjects. Conclusions: According to literature, our data confirm that a severe drop or a disappearance of mMEPs amplitude at the end of surgery has a higher possibility to present permanent deficits. We also confirm that a low percentage of patients could report the absence of deficits in spite of mMEPs deterioration or, vice versa, some degree of motor deficits in spite of preserved mMEPs. IOM improved our surgical results and minimized the risk of permanent severe neurological deficits.