Background
Electrode-imbedded endotracheal tubes allow continuous intraoperative assessment of
vocal cord function when connected to an electromyographic (EMG) response monitor.
Whether this device enhances or hinders the identification and preservation of the
recurrent laryngeal nerve (RLN) is unclear.
Methods
The utility of continuous intraoperative neurophysiology testing (INT) of RLNs was
evaluated prospectively in 100 patients undergoing 103 thyroid or parathyroid operations,
involving 185 RLNs. The initial experience with 93 RLNs was compared with the subsequent
92 RLNs.
Results
Overall, 97.8% of RLNs were identified intraoperatively: 1.6% visually only, 2.2%
nerve stimulator only, and 94% both. There was 1 transected RLN (1.1%) in each study
group. The EMG monitor could not alert the surgeon to prevent these injuries. Overall,
there were 14 instances of nonfunction of visually intact RLNs (7.6%), at some point
during the operation and 4 resulting in temporary paralysis (2.2%). There were 8 instances
of altered RLN function (4.3%) with no altered vocal cord function postoperatively.
The nerve stimulator aided dissection of the RLN in 17 instances (9.2%). There were
7 episodes (3.8%) of equipment dysfunction that hampered surgical dissection. Between
study groups there was significantly increased use of the nerve stimulator to first
identify the location of the RLN before visual confirmation: 4 of 93, initial group
versus 25 of 92, latter group (P < .001).
Conclusions
INT aids the anatomic identification of the RLN only when a positive EMG response
occurs. A negative EMG response can indicate a non-nerve structure, altered function
of the RLN, or equipment setup malfunction. INT cannot necessarily prevent RLN transection.
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to SurgeryAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Prospective study of postoperative complications after total thyroidectomy for multinodular goiters by surgeons with experience in endocrine surgery.Ann Surg. 2004; 240: 18-25
- Recurrent laryngeal nerve paralysis: anatomy and etiology.Otolaryngol Clin North Am. 2004; 37: 25-44
- Comparison of various methods of electromyographic monitoring of the recurrent laryngeal nerve in thyroid surgery.Ann Otol Rhinol Laryngol. 2002; 111: 811-816
- A new method of intraoperative recurrent laryngeal nerve monitoring.Ear Nose Throat J. 1994; 73: 30-33
- Neuromonitoring in thyroid surgery: prospective evaluation of intraoperative electrophysiological responses for the prediction of recurrent laryngeal nerve injury.Ann Surg. 2004; 240: 9-17
- Recurrent laryngeal nerve monitoring in thyroid and parathyroid surgery: the University of Michigan experience.Laryngoscope. 2003; 113: 356-361
- Introperative electromyogram monitoring of the recurrent laryngeal nerve: experience with an intralaryngeal surface electrode. A method to reduce the risk of recurrent laryngeal nerve injury during thyroid surgery.Langenbecks Arch Surg. 1999; 384: 392-395
- Experience with two types of electromyography monitoring electrodes during thyroid surgery.Am J Otolaryngol. 1997; 18: 99-102
- Continuous laryngeal nerve integrity monitoring during thyroidectomy: does it reduce risk of injury?.Otolaryngol Head Neck Surg. 2004; 131: 596-600
- Computer-assisted evoked electromyography with stimulating surgical instruments for recurrent/external laryngeal nerve identification and preservation in thyroid and parathyroid operation.Surgery. 2002; 132: 1100-1106
- Intraoperative monitoring of the recurrent laryngeal nerve in 151 consecutive patients undergoing thyroid surgery.Anesth Analg. 2001; 93: 396-399
- Evaluation of intraoperative recurrent nerve monitoring in thyroid surgery.World J Surg. 2004; 28: 589-591
- Sensitivity and specificity of intraoperative recurrent laryngeal nerve stimulation in predicting postoperative nerve paralysis.Ann Otol Rhinol Laryngol. 2002; 111: 1005-1007
- Laryngeal nerve identification during thyroid surgery—feasibility of a novel approach.Can J Anaesth. 2003; 50: 189-192
- The use of readily available equipment in a simple method for intraoperative monitoring of recurrent larygeal nerve function during thyroid surgery: initial experience with more than 300 cases.Arch Surg. 2002; 137: 452-456
- Laryngeal mask anesthesia with intraoperative laryngoscopy for identification of the recurrent laryngeal nerve during thyroidectomy.Laryngoscope. 2002; 112: 1594-1597
- Risk factors of paralysis and functional outcome after recurrent laryngeal nerve monitoring in thyroid surgery.Surgery. 2004; 136: 1310-1322
Article info
Publication history
Accepted:
August 19,
2005
Temple, TexIdentification
Copyright
© 2005 Mosby, Inc. Published by Elsevier Inc. All rights reserved.
