Influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve during thyroid surgery.

BACKGROUND The influence of muscle relaxation on the intra-operative neuromonitoring of the recurrent laryngeal nerve during thyroid surgery is unclear. METHODS In a prospective study involving 200 patients undergoing elective thyroid surgery, the influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve was investigated. The patients received balanced anaesthesia with oxygen-nitrous oxide-isoflurane, and rocuronium bromide was used as the non-depolarizing neuromuscular blocking agent. The degree of relaxation was monitored continuously by accelerometry [twitch (% TW)]. Summed action potentials (SAcP) obtained from the vocalis muscle were characterized by the area under the electromyographic curve expressed in millivolt seconds. RESULTS Evoked potentials were obtainable in all patients and at all time points. With decreasing neuromuscular blockade a significant increase in the potentials evoked at the vocalis muscle was observed. At 0% TW SAcP was 1.27 (SD 1.02) mV s. An increase in TW to 10% was accompanied by an increase in SAcP to 2.68 (2.01) mV s (P<0.01). At a TW of 25%, mean SAcPs of 5.08 mV s were recorded. CONCLUSIONS There was a significant difference in the degree of relaxation of the adductor pollicis muscle and the vocalis muscle. The laryngeal muscles exhibited a shorter response time than the adductor pollicis and recovered more quickly. These results confirm the feasibility of intra-operative neuromonitoring of the recurrent laryngeal nerve during neuromuscular blockade.

[1]  E Kruse,et al.  [Effectiveness and results of intraoperative neuromonitoring in thyroid surgery. Statement of the Interdisciplinary Study Group on Intraoperative Neuromonitoring of Thyroid Surgery]. , 2004, Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen.

[2]  C. Sekulla,et al.  Validity of intra-operative neuromonitoring signals in thyroid surgery , 2004, Langenbeck's archives of surgery (Print).

[3]  C. Sekulla,et al.  Intraoperative neuromonitoring of surgery for benign goiter. , 2002, American journal of surgery.

[4]  H. Dralle,et al.  Reduziert das intraoperative Neuromonitoring die Recurrenspareserate bei Schilddrüsenoperationen , 2002 .

[5]  C. Sekulla,et al.  [Does intraoperative nerve monitoring reduce the rate of recurrent nerve palsies during thyroid surgery?]. , 2002, Zentralblatt fur Chirurgie.

[6]  T. Hemmerling,et al.  Comparison of succinylcholine with two doses of rocuronium using a new method of monitoring neuromuscular block at the laryngeal muscles by surface laryngeal electromyography. , 2000, British journal of anaesthesia.

[7]  H. Neumann,et al.  [Intraoperative neuromonitoring of the recurrent laryngeal nerve--routine use in thyroid gland surgery]. , 1998, Langenbecks Archiv fur Chirurgie. Supplement. Kongressband. Deutsche Gesellschaft fur Chirurgie. Kongress.

[8]  C. Meistelman.  Effects on laryngeal muscles and intubating conditions with new generation muscle relaxants. , 1997, Acta anaesthesiologica Belgica.

[9]  C. Meistelman,et al.  Comparison of Twitch Depression of the Adductor Pollicis and the Respiratory Muscles Pharmacodynamic Modeling without Plasma Concentrations , 1994, Anesthesiology.

[10]  R. Weber,et al.  Complications of surgery of the thyroid and parathyroid glands. , 1993, The Surgical clinics of North America.

[11]  B. Weigold.  [The parathyroid glands]. , 1987, Bildgebung = Imaging.

[12]  G. Redl,et al.  Unterschiede in der neuromuskulären Blockade der Kehlkopf- und Thenarmuskulatur nach Relaxation mit Vecuronium* , 1986 .

[13]  H. Gilly,et al.  [Differences in the neuromuscular blockade of the larynx and thenar muscles following relaxation with vecuronium]. , 1986, Laryngologie, Rhinologie, Otologie.