Author/Editor		Gnidovec, B; Golob, P
Title		Elektrofiziološke značilnosti delovanja dolgih senzoričnih prog in internevronskih sistemov hrbtenjače - intraoperativni monitoring hrbtenjače
Translated title		Electrophysiological characteristics of long sensory tracts and interneuronic systems of the spinal cord - intraoperative monitoring of the spinal cord
Type		članek
Source		Med Razgl
Vol. and No.		Letnik 34, št. 3
Publication year		1995
Volume		str. 293-317
Language		slo
Abstract		This article deals with electrophysiological characteristics of the long sensory tracts and the interneuronic system of the spinal cord in patients operated on the spinal cord. Spinal somatosensory evoked potentials (SSEP) were recorded using the subpial and the epidural technique during intraoperative neuromonitoring, which is obligatory in all operations on the spinal cord performed at the Department of Neurosurgery, Ljubljana. The median, tibial and sural nerves were stimulated. Sopmatosensory evoked potentials of the long sensory tracts and of the spinal interneuronic system consist of different elements. Changes in these elements indicate domage to the parts of the spinal cord that generate them. The most stable element of the conducted SSEP are the intial negative waves, which originate in the spinocerebellar tract. Deterioration in the shape of the negative high amplitude potentials (NHP) is the most sensitive indicator of damage to the somatosensory system of the spinal cord. Their disappearance or absence indicate severe damage to the dorsal columns. The negative low amplitude potentials (NLP) are the most sensitive element of the conducted SSEP. Their absence indicates damage to the samotosensory system of the spinal cord. Wich can not be precisely localized. The N11 and N14 waves are the most stable elements of the cevical and lumbo-sacral interneuronic SSEP. Since they remain unchanged even in cases of severe domage to the dorsal columns they most probably originate in the dorsal root entry zone. The N13 and N17 waves are the most frequently changed elements of the cervical and lumbo-sacral interneuronic SSEP. Changes of these two waves suggest the damage to the spinal cord gray matter. High frequency waves seen on the slow negative wave of the interneuronic SSEP or appearing in the place of the absent N13 wave most probably reflect the activity of the somatosensory long tracts.(trunc.)
Summary		V nalogi obravnavamo elektrofiziološke značilnosti dolgih senzoričnih prog in internevronskih sistemov hrbtenjače bolnikov, ki so bili operirani na hrbtenjači. Uporabili smo metodo intraoperativnega nevromonitoringa s somatosenzoričnimi izvabljenimi potenciali, ki je na Kliniki za nevrokirurgijo v Ljubljani obvezen pri vseh posegih na hrbtenjači. Za registracijo odzivov smo uporabili subpaialno in epiduralno tehniko. Dražili smo mediani, tibialni in suralni živec. Somatosenzorični izvabljeni potenciali dolgih prog in internevronskih sistemov hrbtenjače so sestavljeni iz različnih elementov. Spremembe teh elementov so odraz poškodbe predela hrbtenjače, ki je njihov izvor. Najbolj stabilen element prevodnega somatosenzoričnega izvabljenega potenciala hrbtenjače (SIPH) so zabelarna proga. Spremembe prevodnih visokih potencialov (PVP) so najbolj občutljiv pokazatelj okvare somatosenzoričnega sistema hrbtenjače. Njihovo izgonitje ali odsotnost sta odraz hude okvare zadajšnjih stebričkov. Prevodni nizki potenciali (PNP) so najbolj občutljiv element prevodnega SIPH. Njihova odsotnost je znak okvare somatosenzoričnega sistema hrbtenjače, natančnejše lokalizacije okvare pa spremembe teh potencialov ne omogočajo. Valova N11 in N14 sta najbolj stabilna elementa vratnih in ledveno-križnih internevronskih SIPH. Ker sta ohranjena tudi pri hudih okvarah zadajšnjih stebričkov, je njun izvor najverjetneje v predelu vstopa zadajšnjih korenin v hrbtenjačo. Valova N13 N17 sta elementna vratnih in ledveno-križnihničnih internevronskih SIPH, ki sta najpogosteje spremenjena. Spremembe teh valov odražajo okvare hrbtenjačne sivine. Visokofrekvenčni valovi, ki so naneseni na počasen negativen val intervronskega SIPH ali pa se pojavljajo na mestu odsotnega vala N13, odražajo aktivnost dolge proge somatosenzoričnega sistema hrbtenjače, najverjetneje kuneatnega svežnja. Spremembe elementov SIPH so povezane s predin pooperativnimi motnjami občutkov.(krajš.)
Descriptors		SPINAL CORD DISEASES INTRAOPERATIVE PERIOD EVOKED POTENTIALS, SOMATOSENSORY MEDIAL NERVE TIBIAL NERVE