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P109 Spinal cord monitoring in anterior cervical discectomy
C o m m u n i c a t i o n s affich4es/Posters
PI09
75S
PllO
SPINAL CORD M O N I T O R I ~ IN M ~ E R I O R CERVICAL DISCECTOMY R.Donati*) E.Fava*, A.Ducati#, R.VJllani*. Inst.of Neurosurgery) University Of Milano (*) and Ancona (#)) Italy. Anterior discectc~ny (AD) is performed for treatment of cervical radiculopathies and mielopathies) due to degenerative changes of the intePJertebral discs and segmental c(xnpress~on by bony spurs. Neurophyslological monitoring of the spinal cord is usually requested by the neurosurgeons in our d~partment) in order to prevent unwanted neural injury, that is mostly feared in the phases of spine distraction and impaction of the bone graft. We report the ezperienee of fifty cervical ADs) performed with Cloward's technique in the Institute of Neurosurgery of the University o f Milano. Our procedure included recording of SomatosensorT/ Evoked Potentials (SEP) by upper and lower limb stimulation. Median nerve (MN) at the wrist and posterior tiblal nerve (FTN) at the ankle were unilaterally stimulated in separate trials. Peripheral (Erb's point and C7 for MN SEP) lumbar point for BTN SEP) and cortical wavefor~ns ~ere collected. Lower limb S E P ) when present preoperatively) provided the highest sensitivity in signalling intraoperatlve changes. Transient amplitude reductions developed in the phases when the drill was used, during inserction of the bone graft) and at the release of distraction after the grafting. Unfortunately lower limb SER were quite sensitive to anesthetics. Upper limb SEP could always be recorded preoperatively) even if they were often asymmetrical) and they ~e)'e more resistant to drugs than PTN SEP. Moreover) they also provide a means o f monitoring neural conduction thrugh the lo~er cervical roots) whenever they are ii~volved in the operation. Most of the SEP changes observed Jntraopematively were not related to postoperative worsening of the patients. This negative result does not challenge the reliability o{ the technique) sinte any SEP changes ~ere reported to tile surgeons and we cannot ext:lilde that an early recognition of impending neural dama£e succeeded in avoiding permanent injury. Both upper and 1o~er llmb SEP should always be recorded in cervical spinal cord tQonitorlng) since they show different susceptibility to Intraoperatlve events.
ETUDE PAR EEG QUANTIFIE DE L ' EFFET DU FLUMAZENIL AU COURS DE L' E N C E P H A L O P A T H I E H E P A T I Q U E ( EH ) . S. P r i e r * , J. B e r n u a u * * , C. B e n o i t * , E. G i o s t r a * * * L a b o r a t o i r e EFSN P r J. C a m b i e r , * * S e r v i c e d ' H e p a t o l o g i e Pr jP. Benhamou . H6pital Beaujon, Clichy (France) Des travaux recents font etat de modifications d e I' a c t i v i t e d e s n e u r o n e s G A B A e r g i q u e s a u c o u r s d e I' EH . L e but de ce travail est d' 6valuer l'effet d' une injection IV iente de 3 mg de Flumazenil , inhibiteur des Benzodiazepines (BZD) , s u r la v i g i l a n c e e t I' EEG q u a n t i f i e a u c o u r s d e I' EH . O n z e m a l a d e s ~ g e s d e 1 7 /~ 5 8 a n s o n t e r e e t u d i e s ( 7 cirrhoses , 4 hepatites fulminantes ) . Aucun n' a recu prealablement d e BZD . N o u s a v o n s o b s e r v e d a n s u n c a s un eveil avec reponse propositionnelle a des questions simples, et dans un autre un grand etat d'agitation. Deux malades ont presente des reactions d' eveil et d' orientation sans qu'il soit possible d'etablir de contact . Chez les sept autres malades , aucune modification comportementale appreciable n'a ere constatee. L' EEG q u a n t i f i e o b j e c t i v e l a r i c h e s s e e n o n d e s l e n t e s . Comprise e n t r e 0 , 5 e t 3 , 5 H z , la f r e q u e n c e moyenne Booleenne varie peu chez un m0me sujet dans l'heure qui s u i t le d e b u t d e I' i n j e c t i o n . Elle s' a c c e l e r e a u c o u r s d e la s t i m u l a t i o n c h e z lee d e u x m a l a d e s d e n t I' a m e l i o r a t i o n a e t e la p l u s n e t t e . L e r a p p o r t d e s p u i s s a n c e s T h e t a / D e l t a augmente d'environ 10% c h e z t r o i s m a l a d e s , d e n t d e u x ont une amelioration clinique. A u t o t a l , le F l u m a z e n i l ne semble pas susceptible de modifier l'etat de vigilance des encephalopathies graves e n I' a b s e n c e d e t r a i t e m e n t prealable par les BZD.
Pill J
ACOUSTIC, SOMATOSENSORY A N D MOTOR EVOKED POTENTIALS IN "LOCKED-IN" SYNDROME.
A.Landi, F.Colombo) M . M a r c h i ~ , U.Fornezza, 8.P.DeLuca. D e p t . of Neurosurgery and ~Inst. o f Neuroradiology, Oeneral Hospital, Vicenza, Italy. A patient suffering from an i s c h e m i c " l o c k e d in" s y n d r o m e following a subarachnoid hemorrage was evaluated by m e a n s of B r a i n s t e m Acoustic Evoked Potentials (BAEPs), Somatosensory Evoked Potentials (SEF's) and Motor Evoked Potentials (MEPs). Neuroradiological findings failed to reveal any d e r a n g e m e n t in the b r a i n stem, w h i l e a TC Doppler showed vasospasm in the vertebral a r t e r y . B A E P s upon m o n o a u r a l s t i m u l a t i o n , with Cz vs. m a s t o i d r e f e r e n c e s and S E P s u p o n m e d i a n nerve stimulation, with E r b point/SC2/C3'-C4' vs. m a s t o i d r e f e r e n c e s , were recorded within 48 h o u r s f r o m the e v e n t ; in a d d i t i o n M E P s u p o n c o r t i c a l , c e r v i c a l and Erb point magnetic stimulation were recorded from APB and EDL bilaterally. BAEPs showed a V/I ratio i n v e r s i o n on b o t h sides; SEPs presented with n o r m a l C C T but c o r t i c a l w a v e s on o n e s i d e w e r e not reproduceable; cortical MEPs were absent on o n e s i d e and h e a v y d e r a n g e d on the other, w h i l e cervical and peripheral MEPs were normal. In c o n c l u s i o n , neurophyeiological findings showed a severe impairment of c o r t i c o s p i n a l p a t h w a y s and a s l i g h t d a m a g e affecting m o r e p o s t e r i o r brain stem structures~ s u c h as m e d i a l a n d lateral lemnisci. Since radiological findings lacked to show brain stem ischemia, functional data w e r e of g r e a t u t i l i t y to c o n f i r m the c l i n i c a l p i c t u r e .
Pl12 SERIAL
RECORDING
OF
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ACOUSTIC
EVOKED
POTEN-
T I A L S I N COMATOSE P A T I E N T S . C.Bianco, E. Bo, E . M a r o t t a , L.Tarenzi, P.Benna, P.Costa, S.Vighetti, G.F.Lamberti, A.Sciarretta, V.Segala,A.De Luca, B.Bergamasco, Turin (Italy) T h e a i m o f o u r s t u d y is t o v e r i f y i f s o m e e v e n t re lated potentials could be recorded in comatose patients and to estab]ish their predictive value in the outcome of the coma. 16 c o m a t o s e patients,aged 18-51 years, following severe head injury admitted to a I . C . U . h a v e b e e n w e e k l y submitted to a s e r i a l recordings of the brainstem auditory evoked potentials (BAEPs) and the event-related potentials (ERPs) by passive auditory add-ball paradigm. In some patients a PS-like component was observed in t h e E R P s r e c o r d i n g s . His reliability seems to well correlate with a good outcome, whereas his absence or disappearance m i g h t to c o r r e l a t e with an unfavourable prognosis.
PI09
75S
PllO
SPINAL CORD M O N I T O R I ~ IN M ~ E R I O R CERVICAL DISCECTOMY R.Donati*) E.Fava*, A.Ducati#, R.VJllani*. Inst.of Neurosurgery) University Of Milano (*) and Ancona (#)) Italy. Anterior discectc~ny (AD) is performed for treatment of cervical radiculopathies and mielopathies) due to degenerative changes of the intePJertebral discs and segmental c(xnpress~on by bony spurs. Neurophyslological monitoring of the spinal cord is usually requested by the neurosurgeons in our d~partment) in order to prevent unwanted neural injury, that is mostly feared in the phases of spine distraction and impaction of the bone graft. We report the ezperienee of fifty cervical ADs) performed with Cloward's technique in the Institute of Neurosurgery of the University o f Milano. Our procedure included recording of SomatosensorT/ Evoked Potentials (SEP) by upper and lower limb stimulation. Median nerve (MN) at the wrist and posterior tiblal nerve (FTN) at the ankle were unilaterally stimulated in separate trials. Peripheral (Erb's point and C7 for MN SEP) lumbar point for BTN SEP) and cortical wavefor~ns ~ere collected. Lower limb S E P ) when present preoperatively) provided the highest sensitivity in signalling intraoperatlve changes. Transient amplitude reductions developed in the phases when the drill was used, during inserction of the bone graft) and at the release of distraction after the grafting. Unfortunately lower limb SER were quite sensitive to anesthetics. Upper limb SEP could always be recorded preoperatively) even if they were often asymmetrical) and they ~e)'e more resistant to drugs than PTN SEP. Moreover) they also provide a means o f monitoring neural conduction thrugh the lo~er cervical roots) whenever they are ii~volved in the operation. Most of the SEP changes observed Jntraopematively were not related to postoperative worsening of the patients. This negative result does not challenge the reliability o{ the technique) sinte any SEP changes ~ere reported to tile surgeons and we cannot ext:lilde that an early recognition of impending neural dama£e succeeded in avoiding permanent injury. Both upper and 1o~er llmb SEP should always be recorded in cervical spinal cord tQonitorlng) since they show different susceptibility to Intraoperatlve events.
ETUDE PAR EEG QUANTIFIE DE L ' EFFET DU FLUMAZENIL AU COURS DE L' E N C E P H A L O P A T H I E H E P A T I Q U E ( EH ) . S. P r i e r * , J. B e r n u a u * * , C. B e n o i t * , E. G i o s t r a * * * L a b o r a t o i r e EFSN P r J. C a m b i e r , * * S e r v i c e d ' H e p a t o l o g i e Pr jP. Benhamou . H6pital Beaujon, Clichy (France) Des travaux recents font etat de modifications d e I' a c t i v i t e d e s n e u r o n e s G A B A e r g i q u e s a u c o u r s d e I' EH . L e but de ce travail est d' 6valuer l'effet d' une injection IV iente de 3 mg de Flumazenil , inhibiteur des Benzodiazepines (BZD) , s u r la v i g i l a n c e e t I' EEG q u a n t i f i e a u c o u r s d e I' EH . O n z e m a l a d e s ~ g e s d e 1 7 /~ 5 8 a n s o n t e r e e t u d i e s ( 7 cirrhoses , 4 hepatites fulminantes ) . Aucun n' a recu prealablement d e BZD . N o u s a v o n s o b s e r v e d a n s u n c a s un eveil avec reponse propositionnelle a des questions simples, et dans un autre un grand etat d'agitation. Deux malades ont presente des reactions d' eveil et d' orientation sans qu'il soit possible d'etablir de contact . Chez les sept autres malades , aucune modification comportementale appreciable n'a ere constatee. L' EEG q u a n t i f i e o b j e c t i v e l a r i c h e s s e e n o n d e s l e n t e s . Comprise e n t r e 0 , 5 e t 3 , 5 H z , la f r e q u e n c e moyenne Booleenne varie peu chez un m0me sujet dans l'heure qui s u i t le d e b u t d e I' i n j e c t i o n . Elle s' a c c e l e r e a u c o u r s d e la s t i m u l a t i o n c h e z lee d e u x m a l a d e s d e n t I' a m e l i o r a t i o n a e t e la p l u s n e t t e . L e r a p p o r t d e s p u i s s a n c e s T h e t a / D e l t a augmente d'environ 10% c h e z t r o i s m a l a d e s , d e n t d e u x ont une amelioration clinique. A u t o t a l , le F l u m a z e n i l ne semble pas susceptible de modifier l'etat de vigilance des encephalopathies graves e n I' a b s e n c e d e t r a i t e m e n t prealable par les BZD.
Pill J
ACOUSTIC, SOMATOSENSORY A N D MOTOR EVOKED POTENTIALS IN "LOCKED-IN" SYNDROME.
A.Landi, F.Colombo) M . M a r c h i ~ , U.Fornezza, 8.P.DeLuca. D e p t . of Neurosurgery and ~Inst. o f Neuroradiology, Oeneral Hospital, Vicenza, Italy. A patient suffering from an i s c h e m i c " l o c k e d in" s y n d r o m e following a subarachnoid hemorrage was evaluated by m e a n s of B r a i n s t e m Acoustic Evoked Potentials (BAEPs), Somatosensory Evoked Potentials (SEF's) and Motor Evoked Potentials (MEPs). Neuroradiological findings failed to reveal any d e r a n g e m e n t in the b r a i n stem, w h i l e a TC Doppler showed vasospasm in the vertebral a r t e r y . B A E P s upon m o n o a u r a l s t i m u l a t i o n , with Cz vs. m a s t o i d r e f e r e n c e s and S E P s u p o n m e d i a n nerve stimulation, with E r b point/SC2/C3'-C4' vs. m a s t o i d r e f e r e n c e s , were recorded within 48 h o u r s f r o m the e v e n t ; in a d d i t i o n M E P s u p o n c o r t i c a l , c e r v i c a l and Erb point magnetic stimulation were recorded from APB and EDL bilaterally. BAEPs showed a V/I ratio i n v e r s i o n on b o t h sides; SEPs presented with n o r m a l C C T but c o r t i c a l w a v e s on o n e s i d e w e r e not reproduceable; cortical MEPs were absent on o n e s i d e and h e a v y d e r a n g e d on the other, w h i l e cervical and peripheral MEPs were normal. In c o n c l u s i o n , neurophyeiological findings showed a severe impairment of c o r t i c o s p i n a l p a t h w a y s and a s l i g h t d a m a g e affecting m o r e p o s t e r i o r brain stem structures~ s u c h as m e d i a l a n d lateral lemnisci. Since radiological findings lacked to show brain stem ischemia, functional data w e r e of g r e a t u t i l i t y to c o n f i r m the c l i n i c a l p i c t u r e .
Pl12 SERIAL
RECORDING
OF
LATE
ACOUSTIC
EVOKED
POTEN-
T I A L S I N COMATOSE P A T I E N T S . C.Bianco, E. Bo, E . M a r o t t a , L.Tarenzi, P.Benna, P.Costa, S.Vighetti, G.F.Lamberti, A.Sciarretta, V.Segala,A.De Luca, B.Bergamasco, Turin (Italy) T h e a i m o f o u r s t u d y is t o v e r i f y i f s o m e e v e n t re lated potentials could be recorded in comatose patients and to estab]ish their predictive value in the outcome of the coma. 16 c o m a t o s e patients,aged 18-51 years, following severe head injury admitted to a I . C . U . h a v e b e e n w e e k l y submitted to a s e r i a l recordings of the brainstem auditory evoked potentials (BAEPs) and the event-related potentials (ERPs) by passive auditory add-ball paradigm. In some patients a PS-like component was observed in t h e E R P s r e c o r d i n g s . His reliability seems to well correlate with a good outcome, whereas his absence or disappearance m i g h t to c o r r e l a t e with an unfavourable prognosis.