Article
Electrophysiological changes of median nerve conduction following pituitary surgery for acromegaly
Elektrophysiologischer Verlauf der N. medianus-Leitfunktion nach Hypophysenchirurgie bei Akromegalie
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Published: | May 4, 2005 |
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Outline
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Objective
Acromegaly is often associated with compression of the median nerve leading to signs and symptoms of the carpal tunnel syndrome. Aim of the current study was to measure electrophysiological changes before and after resection of the growth hormone producing pituitary adenoma.
Methods
Fifteen consecutively treated patients with acromegaly were clinically examined before, 1 week, 3 weeks, 3 months and one year after transsphenoidal removal of a growth hormone producing adenoma. Patients were monitored endocrinologically and by MR imaging of the pituitary. In addition, electrophysiology of the median nerve including distal motor (dml) and sensory latency (dsl) and sensory nerve conduction velocity (SNCV).
Results
Mean IGF-1 was 789±196 ng/ml before surgery and decreased to 298±128 ng/ml 6 weeks after surgery. Seven patients had clinical signs of median nerve compression. 4/30 hands had already had surgery for carpal tunnel syndrome before the diagnosis of acromegaly. Electrophysiology was pathological in 9 patients. Electrophysiological parameters showed a tendency to improve within one week after surgery already. Dml measured 6.8±6.8ms preoperatively and decreased to 4.9±2.6ms three months after surgery (p<0.01). The same improvement was found for the dsl. The parameter decreased significantly from 4.5±0.8ms to 4.1±0.7ms three months after surgery (p<0.001). SNCV was 40.3±8.7m/s (normal >45m/s) and continuously increased within 3 months to 45.2±8.3m/s (p<0.001). No further improvement of these parameters was seen after one year.
Conclusions
Serial measurements of several motor and sensory conduction parameters of the median nerve in acromegaly before and after surgery showed a continuous improvement within three months after removal of the adenoma. No further improvement was seen after one year. We conclude that control investigations for monitoring of median nerve function in acromegaly is best at three months after surgery. Sensory parameters seem to be superior to motor parameters.