Artikel
Prognostic value of motor-evoked potentials in patients operated on space-occupying processes in the spinal canal
Interpretation von Potentialveränderungen beim intraoperativen Neuromonitoring von Hirnstammläsionen
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Autoren
Veröffentlicht: | 23. April 2004 |
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Gliederung
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Objective
The clinical symptoms of cord compression do not always show an appropriate improvement after decompressive operation of the spinal canal. The authors searched for an objective electrophysiological indicator which could be used for predicting post-operative clinical improvement of these patients.
Methods
Latency and amplitude values of motor responses to transcranial magnetic stimulation (MEP) detected from the m. tibialis anterior have been determined. Values exceeding the average with more than +2.5 SD were established as pathological ones. The exceeding of the pathological values over the normal range was determined in percent.
Results
3 groups of patients with extramedullary space occupying processes in the spinal canal were separately examined:
1. no clinical sings and normal MEP values both prae- and postoperatively (No: 7);
2. praeoperative paresis with pathological MEP latencies which exceeded the upper limit of normal values by less than 30 %. Paresis recovered and MEP latencies returned to the normal range postoperatively (No: 9);
3. Pathological MEP latencies exceeded the upper limit of normal values by more than 30 %. Praeop paresis improved but not recovered completely, pathological MEP latencies shortened (No: 8).
Conclusions
According to our results, latency of preoperative MEP carry predictive value as far as postoperative recovery is concerned. No complete recovery of muscular strength is expected when MEP latencies exceed the upper limit of the normal range by more than 30 %.