Jonathan W. Serpell

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. Laryngoscope, 121:S1–S16, 2011

External branch of the superior laryngeal nerve monitoring during thyroid and parathyroid surgery: International Neural Monitoring Study Group standards guideline statement.

Intraoperative neural monitoring (IONM) during thyroid surgery has gained widespread acceptance as an adjunct to the gold standard of visual identification of the recurrent laryngeal nerve (RLN). Contrary to routine dissection of the RLN, most surgeons tend to avoid rather than routinely expose and identify the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy or parathyroidectomy. IONM has the potential to be utilized for identification of the EBSLN and functional assessment of its integrity; therefore, IONM might contribute to voice preservation following thyroidectomy or parathyroidectomy. We reviewed the literature and the cumulative experience of the multidisciplinary International Neural Monitoring Study Group (INMSG) with IONM of the EBSLN. A systematic search of the MEDLINE database (from 1950 to the present) with predefined search terms (EBSLN, superior laryngeal nerve, stimulation, neuromonitoring, identification) was undertaken and supplemented by personal communication between members of the INMSG to identify relevant publications in the field. The hypothesis explored in this review is that the use of a standardized approach to the functional preservation of the EBSLN can be facilitated by application of IONM resulting in improved preservation of voice following thyroidectomy or parathyroidectomy. These guidelines are intended to improve the practice of neural monitoring of the EBSLN during thyroidectomy or parathyroidectomy and to optimize clinical utility of this technique based on available evidence and consensus of experts.

RADICAL LYMPH NODE DISSECTION FOR MELANOMA

Background:  Therapeutic lymph node dissection for melanoma aims to achieve regional disease control. Radical lymphadenectomy (RLND) can be a difficult procedure associated with significant postoperative morbidity.

AUSTRALIAN ENDOCRINE SURGEONS GUIDELINES AES06/01. POSTOPERATIVE PARATHYROID HORMONE MEASUREMENT AND EARLY DISCHARGE AFTER TOTAL THYROIDECTOMY: ANALYSIS OF AUSTRALIAN DATA AND MANAGEMENT RECOMMENDATIONS

Background:  The risk of hypocalcaemia after thyroidectomy has traditionally mandated inpatient monitoring for signs and symptoms as well as frequent measurement of serum calcium levels. In recent years there has been much interest in the published work about the use of intact parathyroid hormone (PTH) to better predict hypocalcaemia after thyroidectomy. Although generally accurate, the use of intact parathyroid hormone in Australia has not become widespread. On behalf of the Australian Endocrine Surgeons an analysis of Australian data on the use of PTH levels to predict hypocalcaemia after thyroidectomy was carried out. The data were analysed with a view to making recommendations about the use of this test in clinical practice and the feasibility of achieving safe early discharge for patients.

The Motor Fibers of the Recurrent Laryngeal Nerve Are Located in the Anterior Extralaryngeal Branch

Objective:This study aimed to establish the prevalence of extralaryngeal bifurcation of the recurrent laryngeal nerve (RLN) and investigate the location of the motor fibers to the intrinsic muscles of the larynx within the branches of the RLN. Summary of Background Data:Recognition of extralaryngeal branching of the RLN is important, because inadvertent division of a branch may lead to significant vocal cord palsy despite the operator believing the nerve was preserved. Methods:Prospective operative data on branching of the RLN were collected in 579 patients undergoing thyroidectomy or open parathyroidectomy over a 3 year period and nerve integrity monitoring was utilized to document the position of the motor fibers of the last 176 RLNs. Adduction of the vocal cords was detected by the electromyography–endotracheal tube and abduction by finger palpation of muscle contraction in the posterior cricoarytenoid. Results:A total of 838 RLN were studied (right–432, left–406). Bifurcations occurred on the right in 111 (25.7%) and left 93 (22.9%). Bilateral bifurcation occurred in 23 (8.9%) of bilaterally dissected nerves. Overall 176 RLNs in 118 patients were assessed by the nerve integrity monitoring. Of these 41 (23.3%) were bifid RLN. In all 41 (100%) cases of bifid RLN, motor fibers for both adduction and abduction of the vocal cords were located exclusively in the anterior branches of RLN, and none in the posterior branches. Conclusion:Extralaryngeal bifurcation of RLN is a common anatomical variant. The motor fibers of RLN are located in the anterior branch, for both adduction and abduction. Great care is therefore required following the presumed identification of the RLN to ensure there is no unidentified anterior branch.

Fine-needle aspiration cytology of thyroid nodules: How useful is it?

Background:  Thyroid nodules are common and the principal method of diagnosis is fine‐needle aspiration cytology (FNAC).

Recurrent laryngeal nerve injury in thyroid surgery: a review

Recurrent laryngeal nerve palsy (RLNP) is an important and potentially catastrophic complication of thyroid surgery. Permanent RLNP occurs in 0.3–3% of cases, with transient palsies in 5–8%. A literature review and analysis of recent data regarding RLNP in thyroid surgery was performed, with particular focus on the identification of high‐risk patients, the role of intraoperative identification and dissection of the nerve, and the role of intraoperative neuromonitoring (IONM) and optimal perioperative nerve assessment. In conjunction with the review, data from the Monash University/Alfred Hospital Endocrine Surgery Unit between January 2007 and October 2011 were retrospectively analysed, including 3736 consecutive nerves at risk (NAR). The current literature and our data confirm that patients undergoing re‐operative thyroid surgery and thyroid surgery for malignancies are at increased risk of RLNP. Intraoperative visualization and capsular dissection of the RLN remain the gold standard for intraoperative care during thyroid surgery for reducing RLNP risk. IONM should not be used as the sole mechanism for identifying and preserving the nerve, although it can be used to aid in the identification and dissection of the nerve, and may aid in nerve protection in high‐risk cases including cancer surgery and re‐operative surgery.

SAFETY OF TOTAL THYROIDECTOMY

Background:  Total thyroidectomy is the preferred operation for multinodular goitre, Graves’ disease and thyroid cancer. This study reviewed prospectively collected data on a personal consecutive series of 336 total thyroidectomies to assess whether results reported in world centres of excellence could also be achieved elsewhere.

Hypothyroidism Following Hemithyroidectomy: A Retrospective Review

Objective:To investigate the incidence, time to onset, and risk factors for the development of hypothyroidism after hemithyroidectomy. Background:The incidence and risk factors for hypothyroidism in patients undergoing partial thyroid surgery remains unclear. Hypothyroidism is an under appreciated sequel of hemithyroidectomy. The early recognition of this postoperative complication may prevent symptoms of hypothyroidism and recurrent thyroid disease. Methods:We conducted a retrospective review of all patients undergoing hemithyroidectomy from August 1992 to June 2006 by a single surgeon. Patients were analyzed for age, sex, family history of thyroid disease, thyroid antibody levels, pre- and postoperative thyroid stimulating hormone (TSH), histologic diagnosis, weight of resected tissue, histologic evidence of thyroiditis, and lag time to diagnosis of hypothyroidism. χ2 or Fisher exact test or Student t test were performed. Results:Hypothyroidism was diagnosed in 10.9% of 294 patients. The mean time to diagnosis was 8.2 ± 10.9 months. The mean thyroxine dose was 69.4 ± 31.6 micrograms. Patients with postoperative hypothyroidism had a higher incidence of a high-normal preoperative TSH level (TSH: 2.5–4.0 mIU/L, 18.8% vs. 3.8%; P < 0.01), thyroiditis on histology (46.8% vs. 11.8%; P < 0.01) and elevated thyroid antibodies levels (47.8% vs. 11.5%; P < 0.01). Age, gender, family history of thyroid disease, thyroid pathology, and weight of resected tissue were not significant risk factors for hypothyroidism. Conclusions:An incidence of 10.9% is higher than anticipated and all patients should have postoperative thyroid function assessment. However, a high-normal preoperative TSH, elevated thyroid antibody levels, and the presence of thyroiditis on histology are indications for close monitoring.

Differential recurrent laryngeal nerve palsy rates after thyroidectomy.

INTRODUCTION Recurrent laryngeal nerve (RLN) palsy is a devastating complication of thyroidectomy. Although neurapraxia is thought to be the most common cause, the underlying mechanisms are poorly understood. The objectives of this study were to examine the differential palsy rates between the left and right RLNs, and the role of intraoperative nerve swelling as a risk factor of postoperative palsy. METHODS Thyroidectomy data were collected, including demographics, change in RLN diameter, and RLN electromyographic (EMG) reading. Left and right RLNs, as well as bilateral and unilateral subgroup analyses were performed. RESULTS A total of 5,334 RLNs were at risk in 3,408 thyroidectomies in this study. The overall RLN palsy rate was 1.5%, greater on the right side than the left for bilateral cases (P = .025), and greater on the left side than the right for unilateral cases (P = .007). In a subgroup of 519 RLNs, the diameter and EMG amplitude were measured. The RLN diameter increased by approximately 1.5-fold (P < .001), and corresponded to increased EMG amplitude (P = .01) during the procedure. The diameter of the right RLN was larger than the left RLN, both at the beginning and end of the dissection (P = .001). CONCLUSION The right-left differential rates of post-thyroidectomy RLN palsy seemed to be due in part to differential RLN diameters, with stretch having a more deleterious effect on RLNs with a smaller diameter; also, edema as a result of stretch might be an underlying mechanism for postoperative neurapraxia and palsy. Thyroid surgeons should be aware of the different vulnerabilities of each RLN and develop practices to avoid iatrogenic injury.