The use of readily available equipment in a simple method for intraoperative monitoring of recurrent laryngeal nerve function during thyroid surgery: initial experience with more than 300 cases

Accelerometry May be Superior to EMG for Early Evaluation of Vocal Cord Function After Nerve Injury in a Pig Model

OBJECTIVE

Vocal cord (VC) movement has been demonstrated by the use of accelerometry (ACC) to decrease in parallel with the electromyographic amplitude (EMG) during ongoing traction injury to the recurrent laryngeal nerve (RLN). When RLN function recovers, discrepancies between EMG and VC movement have been reported in clinical and experimental studies. The present study was conducted to clarify the actual relationship between EMG and VC movement measured by ACC during nerve recovery.

METHODS

EMG obtained by continuous nerve monitoring (C-IONM) was compared with ACC during traction injury to the RLN, and throughout 40-min nerve recovery. A three-axis linear accelerometer probe was attached to the VC, and ACC data were registered as described. Traction damage was applied to the RLN until there was a 70% amplitude decrease from baseline EMG, or until loss of signal (LOS), that is, EMG values ≤100 μV.

RESULTS

Thirty-two RLN from 16 immature pigs were studied. Correlation between EMG and ACC were calculated during nerve injury and nerve recovery. The mean correlations were for the 70% and LOS group from start to end of traction: 0.82 (±0.17) and 0.87 (±0.17), respectively. Corresponding correlation coefficients during 40-min recovery was 0.50 (±0.48) in the 70% group and 0.53 (±0.33) in the LOS group.

CONCLUSION

There is a high correlation between EMG and VC movement during nerve injury, and a moderate correlation during early nerve recovery. EMG recovery after RLN injury ensures sufficient VC function as assessed by ACC.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:1485-1491, 2024.

Meta-analysis on continuous nerve monitoring in thyroidectomies

In the last decade, the introduction of continuous intraoperative recurrent laryngeal nerve (RLN) monitoring (C-IONM) has enabled the operator to verify the functional integrity of the vagus nerve-recurrent laryngeal nerve (VN-RLN) axis in real-time. We aim to present the current evidence on C-IONM utility for thyroid surgery by conducting the first meta-analysis on this technique. A systematic review of literature was conducted by two independent reviewers via Ovid in the Medline, EMBASE, and Cochrane reviews databases. The search was limited to human subject research in peer-reviewed articles of all languages published between Jan 1946 and April 2020. Medical subject headings (MeSH) terms utilized were thyroid surgery, thyroidectomies, recurrent laryngeal nerve, vagal nerve, monitor, and stimulation. Thirty-eight papers were identified from Ovid, another six papers were identified by hand-search. A random effect meta-analysis was performed with assessment of heterogeneity using the I² value. A total of 23 papers that investigated the use of continuous vagal nerve monitoring during thyroid surgery were identified. The proportion of nerves at risk (NAR) with temporary RLN paralysis postoperation was 2.26% (95% CI: 1.6-2.9, I²  = 37). The proportion of NAR with permanent RLN palsy postoperation was 0.05% (95% CI: 0.08-0.2, I²  = 0). In this meta-analysis, there is one case of temporary vagal nerve paralysis secondary to VN electrode dislodgement, and a case of hemodynamic instability manifested in bradycardia and hypotension in the initial phase of surgery shortly after calibration. C-IONM is a safe and effective means by which RLN paralyses in thyroid surgery can be reduced.

Efficacy of Transcartilaginous Electrodes for Intraoperative Neural Monitoring During Thyroid Surgery

Objectives.

This study was conducted evaluate the efficacy of electromyography (EMG) using transcartilaginous (TC) electrodes through the thyroid cartilage and perichondrium.

Methods.

We prospectively collected EMG data from intraoperative neuromonitoring (IONM) of 54 nerves at risk in 38 patients during thyroidectomy. We followed standardized IONM procedures in all operations. EMG signals from both endotracheal tube (ET) electrodes and TC needle electrodes were recorded simultaneously. We compared the characteristics of the EMG signals and the efficacy of both methods.

Results.

Significantly higher mean EMG amplitudes were recorded by TC electrodes than by ET electrodes in all four-step procedures (V1-R1-R2-V2, P<0.001). Loss of signal (LOS) occurred in five patients in ET electrodes, but in only two patients in TC electrodes. Postoperative laryngoscopy revealed recurrent laryngeal nerve palsy in the two patients who showed LOS from both the ET and TC electrodes, and vocal cord movement was intact in the other three patients. Therefore, the positive predictive values of LOS in ET and TC electrodes were 40% and 100%, respectively.

Conclusion.

EMG recording using TC needle electrodes is feasible and effective, making it a good alternative technique for IONM.

Vocal cord dysfunction following esophageal atresia and tracheoesophageal fistula (EA/TEF) repair

BACKGROUND

The purpose of this study was to determine risk factors and long-term outcomes in patients with esophageal atresia +/-tracheoesophageal fistula (EA/TEF) with vocal cord dysfunction (VCD) owing to recurrent laryngeal nerve (RLN) injury.

METHOD

A retrospective chart review was performed for EA/TEF patients repaired at our institution from 1999 to 2014 (REB #1000032265).

RESULTS

Of 197 patients, 22 (11.2%) were diagnosed with VCD by indirect laryngoscopy following EA/TEF repair. Aspiration was documented on video swallow study for 21 patients, and as a result, 13 required thickened feeds and 8 required gastrostomy tube feeds. Of the 16 H-type TEF patients, 8 (50%) had VCD. Following discharge, 20 (90.9%) patients with VCD eventually tolerated full feeds orally without aspiration but only 8 (36.4%) had documented recovery of vocal cord movement at long-term follow up (mean 452 days). Overall, patients with VCD were more likely to have feeding modifications, increased exposure to radiological studies, and increased frequency of Otolaryngology follow-up compared to EA/TEF patients without VCD.

CONCLUSION

EA/TEF patients are at risk for VCD. Clinical improvement did not always correlate with recovery of VC motion. Strategies to minimize RLN damage will improve outcomes and quality of life for EA/TEF patients.

LEVEL OF EVIDENCE

Level III.

Pneumomediastinum and Bilateral Pneumothoraces Causing Respiratory Failure after Thyroid Surgery

We report the first case of severe respiratory failure after thyroid surgery requiring venovenous extracorporeal membrane oxygenation (vvECMO). The patient was a 41-year-old woman with metastatic thyroid cancer. She underwent thyroidectomy, including left lateral and bilateral central neck dissection. During surgery, the patient developed pneumomediastinum with bilateral pneumothoraces. Despite early treatment with bilateral chest tubes and no evidence of a tracheal perforation, the patient developed severe respiratory failure after extubation on the intensive care unit. Because pneumothorax and pneumomediastinum might be more common than reported, and considering increasing cases of thyroid surgery, staff should remain vigilant of pulmonary complications after thyroid surgery.

[Intraoperative neuromonitoring in thyroid surgery]

BACKGROUND

Intraoperative neuromonitoring of the recurrent laryngeal nerve in thyroid surgery facilitates the identification of anatomical structures in cervical endocrine surgery reducing the frequency of vocal cord paralysis.

OBJECTIVE

To study the normal electrophysiological values of the vague and recurrent laryngeal nerves before and after thyroid surgery. To compare rates of injury of recurrent nerve before and after the introduction of the intraoperative neuromonitoring in thyroid surgery.

MATERIAL AND METHODS

An observational, descriptive and prospective study in which a total of 490 patients were included. Between 2003-2010, surgery was performed on 411 patients (703 nerves at risk) with systematic identification of recurrent laryngeal nerves. Between 2010-2011 neuromonitorization was also systematically performed on 79 patients.

RESULTS

Before the introduction of intraoperative neuromonitoring of 704 nerves at risk, there were 14 recurrent laryngeal nerve injuries. Since 2010, after the introduction of the intraoperative neuromonitoring in thyroid surgery, there has been no nerve injury in 135 nerves at risk.

CONCLUSIONS

We consider the systematic identification of the recurrent laryngeal nerve is the 'gold standard' in thyroid surgery and the intraoperative neuromonitoring of nerves can never replace surgery but can complement it.

Clinical Practice Guideline

Objective

Thyroidectomy may be performed for clinical indications that include malignancy, benign nodules or cysts, suspicious findings on fine needle aspiration biopsy, dysphagia from cervical esophageal compression, or dyspnea from airway compression. About 1 in 10 patients experience temporary laryngeal nerve injury after surgery, with longer lasting voice problems in up to 1 in 25. Reduced quality of life after thyroid surgery is multifactorial and may include the need for lifelong medication, thyroid suppression, radioactive scanning/treatment, temporary and permanent hypoparathyroidism, temporary or permanent dysphonia postoperatively, and dysphagia. This clinical practice guideline provides evidence-based recommendations for management of the patient’s voice when undergoing thyroid surgery during the preoperative, intraoperative, and postoperative period.

Purpose

The purpose of this guideline is to optimize voice outcomes for adult patients aged 18 years or older after thyroid surgery. The target audience is any clinician involved in managing such patients, which includes but may not be limited to otolaryngologists, general surgeons, endocrinologists, internists, speech-language pathologists, family physicians and other primary care providers, anesthesiologists, nurses, and others who manage patients with thyroid/voice issues. The guideline applies to any setting in which clinicians may interact with patients before, during, or after thyroid surgery. Children under age 18 years are specifically excluded from the target population; however, the panel understands that many of the findings may be applicable to this population. Also excluded are patients undergoing concurrent laryngectomy. Although this guideline is limited to thyroidectomy, some of the recommendations may extrapolate to parathyroidectomy as well.

Results

The guideline development group made a strong recommendation that the surgeon should identify the recurrent laryngeal nerve(s) during thyroid surgery. The group made recommendations that the clinician or surgeon should (1) document assessment of the patient’s voice once a decision has been made to proceed with thyroid surgery; (2) examine vocal fold mobility, or refer the patient to a clinician who can examine vocal fold mobility, if the patient’s voice is impaired and a decision has been made to proceed with thyroid surgery; (3) examine vocal fold mobility, or refer the patient to a clinician who can examine vocal fold mobility, once a decision has been made to proceed with thyroid surgery if the patient’s voice is normal and the patient has (a) thyroid cancer with suspected extrathyroidal extension, or (b) prior neck surgery that increases the risk of laryngeal nerve injury (carotid endarterectomy, anterior approach to the cervical spine, cervical esophagectomy, and prior thyroid or parathyroid surgery), or (c) both; (4) educate the patient about the potential impact of thyroid surgery on voice once a decision has been made to proceed with thyroid surgery; (5) inform the anesthesiologist of the results of abnormal preoperative laryngeal assessment in patients who have had laryngoscopy prior to thyroid surgery; (6) take steps to preserve the external branch of the surperior laryngeal nerve(s) when performing thyroid surgery; (7) document whether there has been a change in voice between 2 weeks and 2 months following thyroid surgery; (8) examine vocal fold mobility or refer the patient for examination of vocal fold mobility in patients with a change in voice following thyroid surgery; (9) refer a patient to an otolaryngologist when abnormal vocal fold mobility is identified after thyroid surgery; (10) counsel patients with voice change or abnormal vocal fold mobility after thyroid surgery on options for voice rehabilitation. The group made an option that the surgeon or his or her designee may monitor laryngeal electromyography during thyroid surgery. The group made no recommendation regarding the impact of a single intraoperative dose of intravenous corticosteroid on voice outcomes in patients undergoing thyroid surgery.

Prevention of complications in transaxillary single-incision robotic thyroidectomy

BACKGROUND

Transaxillary robotic thyroidectomy, developed by the Yonsei University group from Seoul, Korea, is a new approach that eliminates the need for a cervical incision. Originally, this technique was performed using a two-incision technique (ipsilateral axilla and anterior chest wall). More recently, the chest wall incision is being eliminated and a less invasive robotic thyroid procedure is being performed through a single axillary incision.

SUMMARY

The complexity of this new technique introduces the potential for new complications particularly during the initial learning curve that are not routinely or previously associated with conventional open thyroidectomy. This article will aide surgeons in overcoming the learning curve of transaxillary single-incision robotic thyroidectomy (TSI-RT), giving a detailed explanation of the robotic surgical procedure, the possible complications, and complication management.

CONCLUSIONS

If surgeons have mastery of the multiple steps of the robotic surgical procedure and a good understanding of possible complications and how to prevent them, TSI-RT can be performed safely and offers numerous advantages over multi-incision robotic thyroidectomy as well as conventional open thyroidectomy.

Acute pulmonary edema secondary to upper airway obstruction by bilateral vocal cord paralysis after total thyroidectomy -A case report-

This paper reports the case of a 65-year-old woman with a history of mild arterial hypertension who presented with acute pulmonary edema immediately after a total thyroidectomy. The edema was found to have been caused by an acute upper airway obstruction secondary to bilateral vocal cord paralysis. Her pulmonary edema resolved with treatment including reintubation, mechanical ventilation with positive end-expiratory pressure, diuretics, morphine, and fluid restriction. This report discusses the possible pathogenesis of this rare clinical situation. This case highlights the possibility of an acute upper airway obstruction caused by bilateral vocal cord paralysis after a total thyroidectomy and the need for prompt treatment to prevent the development of pulmonary edema.

Anatomy of thyroid and parathyroid glands and neurovascular relations

Historically, thyroid surgery has been fraught with complications. Injury to the recurrent laryngeal nerve, superior laryngeal nerve, or the parathyroid glands may result in profound life-long consequences for the patient. To minimize the morbidity of the operation, a surgeon must have an in-depth understanding of the anatomy of the thyroid and parathyroid glands and be able to apply this information to perform a safe and effective operation. This article will review the pertinent anatomy and embryology of the thyroid and parathyroid glands and the critical structures that lie in their proximity. This information should aid the surgeon in appropriate identification and preservation of the function of these structures and to avoid the pitfalls of the operation.

Electrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery: international standards guideline statement

Intraoperative neural monitoring (IONM) during thyroid and parathyroid surgery has gained widespread acceptance as an adjunct to the gold standard of visual nerve identification. Despite the increasing use of IONM, review of the literature and clinical experience confirms there is little uniformity in application of and results from nerve monitoring across different centers. We provide a review of the literature and cumulative experience of the multidisciplinary International Neural Monitoring Study Group with IONM spanning nearly 15 years. The study group focused its initial work on formulation of standards in IONM as it relates to important areas: 1) standards of equipment setup/endotracheal tube placement and 2) standards of loss of signal evaluation/intraoperative problem-solving algorithm. The use of standardized methods and reporting will provide greater uniformity in application of IONM. In addition, this report clarifies the limitations of IONM and helps identify areas where additional research is necessary. This guideline is, at its forefront, quality driven; it is intended to improve the quality of neural monitoring, to translate the best available evidence into clinical practice to promote best practices. We hope this work will minimize inappropriate variations in monitoring rather than to dictate practice options.

Laryngeal mask airways in ear, nose, and throat procedures

The use of laryngeal mask airway (LMA) and its variants in ear, nose, and throat procedures have been extensively described in case reports, retrospective reviews, and randomized clinical trials. The LMA has developed a considerable following because of its lack of tracheal stimulation, which can be a considerable advantage in ear, nose, and throat (ENT) procedures. The incidence of coughing on emergence has been shown to be lower with the LMA than with the endotracheal tube (ETT). Although other approaches to smooth emergence have been described, few would argue that it is as easy to achieve a smooth emergence with an ETT as with an LMA. Although patients certainly exist for whom the LMA is contraindicated, many will experience better results with the LMA because of the features delineated in this article.

Comparing the Long-Term Outcome of Immediate Postoperative Facial Nerve Dysfunction and Vocal Fold Immobility After Parotid and Thyroid Surgery

SUMMARY

HYPOTHESIS

The long-term recovery rate of immediate postoperative facial nerve dysfunction with an electrophysiologically and anatomically intact facial nerve is higher than the long-term recovery rate of immediate postoperative vocal fold immobility with an electrophysiologically and anatomically intact recurrent laryngeal nerve.

METHODS

A retrospective review of parotid and thyroid surgery with electrophysiologic monitoring of the facial and recurrent laryngeal nerves, respectively.

RESULTS

Forty-five consecutive patients had electrophysiologic and anatomic integrity of the facial nerve at the conclusion of the parotidectomy. Eight of 45 (18%) patients developed a postoperative facial nerve dysfunction. All eight patients with facial nerve dysfunction had complete return of facial nerve function within 3 months. A total of 102 consecutive patients underwent dissection of the recurrent laryngeal nerve during thyroid surgery. Seven of 102 (7%) had immediate unilateral vocal fold dysfunction. All 102 had electrophysiologic and anatomic integrity of the recurrent laryngeal nerve at the conclusion of the procedure. Two of 102 (2%) have clinically complete permanent vocal fold dysfunction. Five of seven (71%) with immediate complete vocal fold immobility had complete return of mobility.

CONCLUSIONS

A higher immediate postoperative rate of transient facial nerve dysfunction is reported compared with vocal fold immobility in parotid and thyroid surgery, respectively (P < 0.05). Immediate postoperative facial nerve dysfunction with an electrophysiologically response at 1 mA and an anatomically intact facial nerve during parotid surgery resulted in a complete return of function in all cases in this series. Immediate postoperative vocal fold immobility with an electrophysiological response at 1 mA and an anatomically intact recurrent laryngeal nerve had a 30% rate of being permanent in this series.

Intraoperative neurophysiology testing of the recurrent laryngeal nerve: Plaudits and pitfalls

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.

Laryngeal nerve monitoring during thyroid surgery in pregnancy

A 32-week parturient required partial thyroidectomy for suspicious carcinoma. The surgeon requested laryngeal nerve monitoring to decrease the chances of laryngeal nerve injury during surgery. After rapid-sequence induction of general anesthesia and intubation, a size 3 laryngeal mask airway was inserted posterior to the endotracheal tube and the cuff inflated with 15 mL of air. A fiberoptic bronchoscope inserted through the laryngeal mask airway provided an unhindered view of vocal cords for laryngeal nerve identification and testing during surgery. This combined technique also offered the advantages of a secured airway, as well as positive pressure ventilation in the parturient during thyroid surgery.

Electrophysiologic Laryngeal Nerve Monitoring in High-Risk Thyroid Surgery

We recently began performing intraoperative electrophysiologic monitoring of the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve during high-risk thyroidectomies. Neuromonitoring can detect stimulation of these nerves and thereby prevent a mechanical or thermal injury that can result in neurapraxia or axonotmesis. Monitoring is also useful during dissection in an already operated-on field, when performing thyroidectomy on patients who depend on their voice for their livelihood, and when removing a large goiter or mediastinal mass.

Intraoperative Monitoring of the Recurrent Laryngeal Nerve Using Acoustic, Free-Run, and Evoked Electromyography

The purpose of this study was to explore advantages and disadvantages of electrodes used for monitoring of the recurrent laryngeal nerve (RLN) and to determine the postoperative outcome in 135 patients. A pilot study examined 11 patients to compare the clinical performance of two commercially available recording electrodes and three stimulation electrodes for RLN neuromonitoring. After determining the most reliable and consistent stimulating/recording electrode combination, 124 patients were then monitored. In a total of 135 patients there was no permanent iatrogenic nerve damage to the RLN, although 2 patients developed transient vocal hoarseness that resolved shortly postoperatively. An initial "searching" current for evoked electromyography (EMG) was delivered at 0.7 mA and then decreased to a value of 0.35 mA, which reliably elicited RLN stimulation with a minimal incidence of false-positive results. The combination of auditory feedback from the mechanically elicited EMG and a control channel involving EMG monitoring of an additional peripheral muscle improved the detection of artifact and improved the clinical efficacy of intraoperative electromyography. A video camera showed the surgical manipulation on the EMG screen, allowing the neurophysiologist to correlate dissection with RLN status and location. Auditory responses from the nerve helped to determine the type of distress the RLN was encountering.

Risk factors of paralysis and functional outcome after recurrent laryngeal nerve monitoring in thyroid surgery

BACKGROUND

Recurrent laryngeal nerve monitoring (RLNM) has been suspected to reduce postoperative RLN paralysis (RLNP). However, functional outcome of RLNM in comparison with no nerve identification and visual nerve identification only has not been analyzed.

METHODS

Analysis of 16,448 consecutive multi-institutional operations resulted in 29,998 nerves at risk. Three groups of different RLN treatment were compared: group 1, no RLN identification; group 2, visual RLN identification; and group 3, visual RLN identification and electromyographic monitoring. RLNM was performed with a bipolar needle electrode that was placed through the cricothyroid ligament into the vocal muscle.

RESULTS

Risk factors for permanent RLNP were recurrent benign and malignant goiter (odds ratios, [ORs]), 4.7, and 6.7, respectively), primary surgery in thyroid malignancy (OR, 2.0), lobectomy (OR, 1.8), no nerve identification (OR, 1.4), low or medium volume hospital (OR, 1.3), and low volume surgeons (OR, 1.2).

CONCLUSIONS

Based on these data, visual nerve identification was identified to be the gold standard of RLN treatment in thyroid surgery. RLNM is a promising tool for nerve identification and protection in extended thyroid resection procedures. However, because of the overall low frequency of RLNP, no statistical difference compared with visual nerve identification only was reached in the setting of this study.

Intraoperative electromyographic monitoring of the recurrent laryngeal nerve in reoperative thyroid and parathyroid surgery

BACKGROUND

Injury to the recurrent laryngeal nerve (RLN) is a rare complication of initial thyroid and parathyroid surgery, but the prevalence is much higher in the reoperative setting. The use of continuous, intraoperative electromyographic monitoring of the RLN has been suggested to improve the safety of cervical explorations.

METHODS

Outcomes of a group of reoperative thyroid and parathyroid cases that used EMG monitoring with endoscopically applied hook-wire electrodes were compared with a group of cervical reoperations without monitoring. Office laryngoscopy (indirect or fiberoptic) was used to evaluate and follow suspected RLN complications.

RESULTS

Electromyography was used in 52 cervical reexploration procedures. Patients averaged 1.8 previous explorations (range, 1-7 explorations) and underwent procedures for parathyroid (31%) and/or thyroid (77%) disease (overall, 72% malignant). The non-monitored group had 59 patients with similar characteristics. Only 1 permanent nerve complication in each group was unintended (electromyography, 1.9%; non-electromyography, 1.7%). Seven false-negative and 2 false-positive electromyographic findings occurred. No complications resulted from placement of the electromyography electrodes.

CONCLUSIONS

Intraoperative electromyographic monitoring of the RLN in reoperative neck surgery can be performed safely but did not decrease RLN complications in this study. Experience and routine nerve exposure remain crucial to the minimization of RLN complications.

Developments in general airway management

Since the 1970s, improvements in airway management have been significant. New imaging modalities such as CT and MRI can display airway structures with unparalleled detail, which improves preoperative planning and the treatment of patients with pathologic processes involving the respiratory tract or with difficult-to-manage airways. Because of the introduction of flexible fiberscopes, pulmonologists and thoracic surgeons can diagnose diseases of the respiratory tract effectively and treat patients with these diseases safely. The use of flexible fiberscopes has expanded rapidly into other medical specialties, including anesthesia and critical care. Modem anesthesiologists now use flexible fiberscopes daily to intubate patients safely, especially when traditional intubating techniques fail. The cost of fiberscopes has decreased dramatically, and their optical systems have improved. Several centers of excellence have been developed where clinicians can learn basic and advanced techniques of fiberoptic intubation. The LMA has shown that the supraglottic airway approach is not only feasible, but also in many situations superior to tracheal intubation. Although the LMA initially was recommended as an alternative to the facemask, its use has expanded, benefiting many children and adults undergoing a variety of diagnostic and therapeutic procedures. Use of an LMA in combination with a flexible fiberscope has opened up new possibilities for treating patients safely and effectively while providing optimal comfort during a procedure and has been particularly beneficial in thoracic surgery. The most recent iteration of the ASA Difficult Airway Algorithm has revised further a systematic approach to the clinical care of patients with different types of difficult-to-manage airways.

Recurrent laryngeal nerve paralysis: anatomy and etiology

Etiologies of adult vocal paralysis are varied by the site of the lesion as well as the extent and cause of the damage. Most large series point to surgery and neoplastic causes for recurrent nerve paralysis. A detailed history is important when working up a patient with this voice disorder. Knowledge of the anatomy of the head, neck, and chest as well as the mechanisms behind vocal fold paralysis is essential in the evaluation and treatment of recurrent nerve paralysis. Many of the surgical and traumatic causes of hoarseness are from compression type injuries. Recovery is dependent on the type, extent, and site of nerve lesion. Familiarity with this data allows the otolaryngologist to tailor management to suit each patient with vocal fold paralysis.

Neuromonitoring in thyroid surgery: prospective evaluation of intraoperative electrophysiological responses for the prediction of recurrent laryngeal nerve injury

OBJECTIVE

We evaluated the ability of neuromonitoring to predict postoperative outcome in patients undergoing thyroid surgery for different indications.

SUMMARY BACKGROUND DATA

Neuromonitoring has been advocated to reduce the risk of vocal cord palsy and to predict postoperative vocal cord function.

METHODS

Three hundred twenty-eight patients (502 nerves at risk) were studied prospectively at a single center. Neuromonitoring was performed with the Neurosign 100 device by transligamental placement of the recording electrode into the vocalis muscles. Cumulative distribution of stimulation thresholds was determined by stepwise decreases in current (1 mA to 0.05 mA) for both the vagus and the recurrent nerve. Patients were grouped according to surgical risk (benign and malignant disease, reoperation for benign and for malignant disease).

RESULTS

If the electrophysiological response was correlated to postoperative vocal cord function, the sensitivity of neuromonitoring was modest (86% in surgery for benign disease) to low (25% in reoperation for malignant disease); the positive predictive value was modest (overall rate 62%) but acceptable (87%) if corrected for technical problems. Specificity and negative predictive values were high (ie, overall >95%). Stimulation thresholds were not augmented in 11 patients, in whom postoperative palsy developed despite normal intraoperative recordings. Similarly, an electrical field response was elicited in 14 of 21 patients with preoperative vocal cord palsy. Electromyographic recordings did not reveal an abnormal amplitude or a decline in nerve conduction velocity.

CONCLUSIONS

Neuromonitoring is useful for identifying the recurrent laryngeal nerve, in particular if the anatomic situation is complicated by prior surgery, large tissue masses, aberrant nerve course. However, neuromonitoring does not reliably predict postoperative outcome.

[Overview of the history of thyroid surgery]

Thyroid gland surgery passed through history from the suggestions for prohibition, during middle of XIX century due to unacceptable mortality even for medieval condition, to highest vel of surgical laser, as W. Halsted sad. First thyroidectomy was done by Albucasis (El Zahrawi) in 925 a.d. and after him by Roger from Salerno. While Pierre-Joseph Dusalt in 1791 has done first operation on thyroid gland than can fulfill todays criteria, Teodor Billroth gave scientific grounds of thyroid surgery. Genius attitude and surgical talent of Theodor Kocher raised thyroid surgery o scientific level, brought surgical skills on the top of surgical art pyramid, and brought him personally to the Nobel Prize in 1909. Every important contribution to development of thyroid surgery gave its giants: Johann von Mikulic, William Halsted, Charles Mayo, George W. Crile and Rank Lahey. Thomas P. Dunhill, F.A. Coller, A.M. Boydena and many others did important contribution, too. Development of thyroid srugery was constant to nowadays, with tendention for multidisciplinary approach in specialized centres. Thyroid surgery in Serbia followed this world trends, in spite of treat problems in the area during history.

Intraoperative cranial nerve monitoring

The purpose of intraoperative monitoring is to preserve function and prevent injury to the nervous system at a time when clinical examination is not possible. Cranial nerves are delicate structures and are susceptible to damage by mechanical trauma or ischemia during intracranial and extracranial surgery. A number of reliable electrodiagnostic techniques, including nerve conduction studies, electromyography, and the recording of evoked potentials have been adapted to the study of cranial nerve function during surgery. A growing body of evidence supports the utility of intraoperative monitoring of cranial nerve nerves during selected surgical procedures.

Surgical considerations and controversies in thyroid and parathyroid surgery

The techniques of thyroid surgery have been fully elucidated in several surgical texts and atlases. This article discuss surgical pearls of thyroid and parathyroid surgery. We discuss preoperative, intraoperative, and postoperative considerations and controversies for both procedures.

Early complications of thyroid surgery: Analysis of 2100 patients

Background/Aims. Thyroid gland surgery today is not saddled with high incidence of main complications. Miscellaneous surgical institutions with different surgical approach, operative technique and radicality have published reports with great discrepancy in incidence of complications, analyzing them with different methods of diagnosis and result evaluation. In the same way it is well known that higher latitude of operative procedure gave better control of thyroid diseases, but it can be accompanied with more complications. All of that motivate us to analyze complications of operative treatment in our patients under well known criteria, with hypothesis that higher radicality of operative procedure do not increase incidence of complications, and that this incidence is in correlations with results published in world literature. Aim of this nonrandomized study was to analyze results of operative treatment for huge number of consecutively operated patients in our teaching hospital, to analyze and compare results according to group of diseases and operative procedures, and to compare final results with results published in the world literature. Methods. Complications of operative treatment were analyzed retrospectively for period 1988-1997 (Group I) and prospectively in period 1998-2002 (Group II). Operations were performed by 20 surgeons and 20 young surgeons during their education. We have analyzed only complications during first 30 days after operation. Results. In Group I there was 1425 patients with 1451 operations (192 thyroid malignances, 247 hyperthireosis, 98 reoperations, 13% thyreoidectomies and 14,8% lobectomies), with complication rate of 14,3%. Most common complication was recurrent laryngeal nerve injury in 9,3% patients or 6,3% according to number of exposed nerves (?nerve at risk?), then postoperative hypocalcemia with rate of 4,7% (persistent in 1,3%). In Group II in 675 patients there was 687 operations (96 thyroid malignances, 111 hyperthireosis, 35 reoperations, 36,6% thyreoidectomies and 25% lobectomies), with complication rate of 10,7%. Most common postoperative complication was hypocalcemia with 5% rate (persistent in 0,7%), then recurrent laryngeal nerve injury in 4,4% patients or 2,9% according to number of exposed nerves (?nerve at risk?). Incidence of recurrent laryngeal nerve injury in Group II is less frequent than in Group I, highly statistically significant (p<0,01), while for other complications there is no statistically significant difference. Totally for both groups there was 0,7% tracheotomies, postoperative bleeding in 1,1% of patients, wound haemathoma in 0,5%, wound infections in 0,9%, pneumonia in 0,5%, mortality 0,5% and most common cause of death (8/11) was problem with respiration, ?Airway obstruction?. In Group II complications were less frequent in total thyreoidectomies in relation to lobectomy with contra lateral subtotal lobectomy. In both groups and totally incidence of complications was higher in reoperations, in patients with more extensive operative procedure, in malignant diseases and hyperthyreosis. Conclusion. In thyroid gland surgery more extensive operative treatment with improved operative technique (micro dissection, recurrent laryngeal nerve visualization and parathyroid gland preservation), in our teaching hospital, do not have influence on incidence of postoperative complications, even recurrent laryngeal nerve injury was significantly less frequent. This results are in correlation with published results of similar hospitals around the world.