Article
Doubtful benefit of intra-operative somatosensory evoked potentials (SEP) monitoring including pre-operative positioning tests in patients with degenerative cervical disease
Zweifelhafter Nutzen des intraoperativen SEP-Monitorings inklusive präoperativer Lagerungstests bei Patienten mit degenerativen HWS-Veränderungen
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Authors
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Jochen Helm
- Universitätsklinikum Leipzig, Klinik für Neurochirurgie, Leipzig
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C. Rudolph
- Universitätsklinikum Leipzig, Klinik für Anästhesie und Intensivmedizin, Leipzig
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J. Meixensberger
- Universitätsklinikum Leipzig, Klinik für Neurochirurgie, Leipzig
| Published: | April 23, 2004 |
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Outline
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Objective
A benefit of intraoperative SSEP monitoring in decompressive surgery for degeneration of cervical spine is generally accepted. In view of the low complication rate and unspecific intraoperative SSEP changes, a final evaluation remains difficult. The aim of the study was an acquisition of preoperative SSEP data in normal, reclined and inclined neck positions and to verify a correlation to the risk of intraoperative changes and postoperative neurological deficits.
Methods
From 03/01 to 03/03 we recorded pre-operative and intra-operative SSEP data from 33 patients undergoing operation. We registered the baseline SSEPs as well as influence of pre-operative positioning tests, intra-operative alterations, surgeons reactions and post-operative deficits.
Results
In 24% of the patients there was a pre-operative deterioration of median nerve SSEP (MSEP) signals in positioning tests, in 9% MSEPs improved, in 67% there were stable potentials (TSEP 42% worse, 15% better, 42% unaltered). Intra-operative MSEP deterioration was detected in 76% of the patients, MSEP deterioration in 76% as well. Only in four patients (12%) did we register stable intraoperative SSEP signals. In 8 situations there was an influence of intraoperative SSEP monitoring on the course of the surgery (positioning alteration, increased caution, one operation was aborted). In 4 patients there were postoperative deficits (1 brachiocervical plexus palsy, 2 radicular sensory deficits, 1 new spinal ataxia). Positioning tests of these patients revealed unilateral MSEP twice, and unilateral TSEP deterioration twice; in one patient position testing was without influence on SSEP. In one of the patients there were no intra-operative SSEP changes. In two patients intra-operative alterations did not correlate to neurological deficits, only the patient with the plexus palsy showed unilateral MSEP reduction and delay.
Conclusions
A deterioration of SSEP signals in pre-operative positioning indicated a higher risk of post-operative neurological deficit. However intra-operative alterations were mostly unspecific and did not correlate to post-operative deficits in 3 of our 4 complication patients. The risk of post-operative neurological deficits being reduced by a combination of pre-operative positioning tests and intra-operative SSEP monitoring remains unclear.
