Author/Editor     Prestor, Borut; Golob, Peter
Title     Planning the microsurgical myelotomy in intramedullary tumors or cysts by intraoperative neuromonitoring
Translated title     Izbira mikrokirurške mielotomije pri operacijah tumorjev in cist v hrbtenjači s pomočjo intraoperativnega nevromonitoringa
Type     članek
Source     Zdrav Vestn
Vol. and No.     Letnik 74, št. 4
Publication year     2005
Volume     str. 203-9
Language     eng
Abstract     Background. Surgical approach to the intramedullary tumors and cavities are microsurgical techniques of dorsal myelotomies, which entails the risk of damage to the dorsal columns and the central spinal cord gray matter. The aim of the study is to analyze the clinical sensory dysfunction before surgery and the changes of the intraoperative SEP (somatosensory potentials) before myelotomy. These data would be of help to neurosurgeons in planning the myelotomy - dorsomedial or dorsolateral. Methods. 16 patients were operated on for deafferentation pain syndromes, intramedullary tumors and syringomyelia of the cervical spinal cord. Preoperatively the patients sensory system of dorsal columns and central gray matter was examined for vibration and position sense dysfunction and pain and temperature damage. Before myelotomy the intraoperative SEP from the dorsal surface of the spinal cord after the stimulation of the median and tibial nerves were recorded. Results. After median nerve stimulation the N13 wave was partially or completely absent, and fast negative waves appeared instead. The presence and absence of N13 was in association with pain and temperature dysfunction or with dissociative sensory loss. The mean duration of the SEP potential was shorter than normal (p < 0. 0005, n = 11). After tibial nerve stimulation the first negative waves were most stabile, fast negative waves as the most prominent element of the normal SEP were partially or completely absent. This change was in association with diminution or loss of vibration and posture senses. The duration of the conductive SEP was shorter than normal (p = 0. 064, n = 5). Conclusions. Dissociative sensory loss is associated with absence of the N13 in median nerve SEP and connected to the central cord destruction. T'he loss of vibration and posture senses affects the fast negative waves of tibial SEP and points toward damage of the dorsal columns. (Abstract truncated at 2000 characters).
Summary     Izhodišča. Klinični simptomi in znaki intramedularnih tumorjev in siringomielije večinoma ne dajejo dovolj podatkov za natančno oceno poškodbe živčnih celic zadnjega roga in živčnih vlaken zadnjih stebričkov. Slike hrbtenjače z magnetno resonanco (MR) pokažejo mesto cistične votline ali tumorja v hrbtenjači, vendar ne dajejo informacij o položaju spremembe glede na dolge senzorične proge in zadnje rogove ter ne omogočajo ocene motenj prevajanja živčnih dražljajev v hrbtenjači. Odstranjevanje tumorjev in cist hrbtenjače omogočajo dorzalne mielotomije, ki nosijo tveganje poškodbe zadnjih stebričkov in centralne sivine hrbtenjače. Zato je potrebno objektivno funkcionalno spremljanje delovanja anatomskih predelov hrbtenjače, ki so najbolj izpostavljeni pri odstranjevanju intramedularnih sprememb. Rezultati naše predhodne študije so pri intramedularnih tumorjih in siringomieliji pokazali spremembe elementov somatosenzoričnih evociranih potencialov (SEP), registriranih s pomočjo intraoperativnega nevromonitoringa. Namen prispevka je ugotoviti funkcionalno poškodbo teh delov hrbtenjače s pomočjo senzoričnih izpadov pred operacijo in sprememb elementov intraoperativnih SEP registriranih na hrbtenjači pred mielotomijo. Podatki bi pomagali pri odločitvi za vrsto mikrokirurške mielotomije - za dorzomedialno ali za dorzolateralno mielotomijo. Metode. Podatke smo zbrali pri 16 bolnikih, operiranih zaradi deaferentacijske bolečine (5 bolnikov), intramedularnih tumorjev (5 bolnikov) in siringomielije (6 bolnikov) hrbtenjače. Meritve pri bolnikih z bolečinskim sindromom smo izbrali za normalne podatke, ker niso imeli nevroloških izpadov v distribucijskem področju stimuliranih perifernih živcev. Pred operacijo smo klinično preverili senzorični sistem zadnjih stebričkov in centralnega dela hrbtenjače s preiskavo občutkov za vibracije in položaj sklepov ter bolečine in temperature. (Izvleček skrajšan pri 2000 znakih).
Descriptors     SPINAL CORD NEOPLASMS
SYRINGOMYELIA
MICROSURGERY
INTRAOPERATIVE MONITORING
EVOKED POTENTIALS, SOMATOSENSORY
MAGNETIC RESONANCE IMAGING
MEDIAN NERVE
TIBIAL NERVE