[Epidural anesthesia in surgical interventions on the spine and spinal cord. II. Effects of epidural anesthesia on somatosensory evoked potentials].
Effects of epidural anesthesia (EA) on early components of somatosensory evoked potentials (SSEP) were studied and the objectiveness and efficiency of SSEP monitoring during interventions on the spine under EA were evaluated. Evoked potentials were studied in 21 patients operated on for vertebral disk hernias and extra-intradural tumors of the spine (lower thoracic and lumbar levels) under bupivacaine EA. Cortical SSEP were recorded and analyzed on a Viking IV neuroaverager (Nicolet, USA) stimulating n. tibialis posterior for obtaining a greater amplitude of evoked potentials. The following SSEP characteristics were measured: latency of PI (P37), NI (N45), and PII (P60) peaks, amplitude of PINI peak, and inter-peak latency of PI-NI and PI-PII. The major changes in cortical SSEP caused by EA (local anesthetic 0.5% bupivacaine) involve only PI and NI components which reflect the entry of information on an external stimulus into the cortex and objective physical parameters of this stimulus; this helps predict the onset of full-value epidural block and its duration. General anesthetic (propofol) affect mainly a later component of response, PII peak, which is responsible for processing of primary information about an external stimulus and reflects the activation of associative areas of the brain. Hence, SSEP regulation can be used together with traditional methods (pin prick test and Bromage scale) for evaluating epidural block in patients with spinal diseases.
Solenkova
A V
AV
Safronov
V A
VA
Lubnin
A Iu
AIu
Shevelev
I N
IN
Konovalov
N A
NA
D000328:Adult; D000368:Aged; D000767:Anesthesia, Epidural; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage; D002045:Bupivacaine / Q000008:administration & dosage; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008159:Lumbar Vertebrae; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D015742:Propofol / Q000008:administration & dosage; D013120:Spinal Cord Neoplasms / Q000601:surgery*; D013904:Thoracic Vertebrae
D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D002045:Bupivacaine; D015742:Propofol