A systematic approach to the recurrent laryngeal nerve dissection at the cricothyroid junction

Age-stratified comparison of active surveillance versus radiofrequency ablation for papillary thyroid microcarcinoma using decision analysis

BACKGROUND

Papillary thyroid microcarcinomas may be treated with radiofrequency ablation, active surveillance, or surgery. The objective of this study was to use mathematical modeling to compare treatment alternatives for papillary thyroid microcarcinomas among those who decline surgery. We hypothesized that radiofrequency ablation would outperform active surveillance in avoiding progression and surgery but that the effect size would be small for older patients.

METHODS

We engaged stakeholders to identify meaningful long-term endpoints for papillary thyroid microcarcinoma treatment-(1) cancer progression/surgery, (2) need for thyroid replacement therapy, and (3) permanent treatment complication. A Markov decision analysis model was created to compare the probability of these endpoints after radiofrequency ablation or active surveillance for papillary thyroid microcarcinomas and overall cost. Transition probabilities were extracted from published literature. Model outcomes were estimated to have a 10-year time horizon.

RESULTS

The primary outcome yielded a number needed to treat of 18.1 for the avoidance of progression and 27.4 for the avoidance of lifelong thyroid replacement therapy for radiofrequency ablation compared to active surveillance. However, as patient age increased, the number needed to treat to avoid progression increased from 5.2 (age 20-29) to 39.1 (age 60+). The number needed to treat to avoid lifelong thyroid replacement therapy increased with age from 7.8 (age 20-29) to 59.3 (age 60+). The average 10-year cost/treatment for active surveillance and radiofrequency ablation were $6,400 and $11,700, respectively, translating to a cost per progression-avoided of $106,500.

CONCLUSION

As an alternative to active surveillance, radiofrequency ablation may have a greater therapeutic impact in younger patients. However, routine implementation may be cost-prohibitive for most patients with papillary thyroid microcarcinomas.

A Comparison of Harmonic Scalpel and Conventional Techniques for Thyroidectomy

Thyroidectomy is one of the most frequently performed surgeries. Conventional techniques using electrocautery carry the risk of tissue injury. Recently, there has been increased use of harmonic scalpels in thyroid surgery. The harmonic scalpel utilizes ultrasonic shears for cutting and coagulation, thus minimizing thermal injury. The objective of our study was to determine differences in operative duration, hypocalcemia, and RLN palsy. This single-center retrospective comparative study included consecutive patients undergoing hemithyroidectomies using the harmonic scalpel and conventional technique in the past one year (n = 64, harmonic group = 28 and conventional group = 36). The mean operative duration for the harmonic scalpel group was 70.4 min, vs. 81.31 min for the conventional technique group, and the difference in mean duration was found to be 10.84 min (p = 0.027). There was no statistically significant difference in the rates of hypocalcemia (p = 0.751) or RLN palsy (p = 0.121). None of the patients in either group developed permanent hypocalcemia or RLN palsy. The use of a harmonic scalpel during thyroidectomy is safe. The overall surgical duration was reduced when the harmonic scalpel was used, and the complication rates were comparable to those of the conventional technique, making it a non-inferior technique for surgical intervention in thyroidectomy and warranting harmonic scalpel consideration as a valuable addition to the armamentarium of thyroid surgeons.

An Exposition on Surgical Experiences in Identification, Exposure, and Injuries of Recurrent Laryngeal Nerve (RLN) During Thyroid Operations: Gleanings, Narrative, and the Reflections

BACKGROUND

Identifying and preserving the recurrent laryngeal nerve (RLN) is of paramount importance during thyroid surgeries. Iatrogenic injuries to RLN (RLNI) are considered one of the most serious and feared complications of thyroidectomies. Surgically, there are four routes/approaches (lateral, inferior, superior, and medial) for localizing and identifying the RLN. This study aims to estimate the incidence of RLNI in the context of various approaches taken intra-operatively for nerve localization and identification.

MATERIALS AND METHODS

This retrospective analytical study included 54 cases of thyroidectomies operated for various benign and malignant thyroid disorders in a tertiary care center from January 2018 to December 2020. Intraoperative search, identification, and dissection of the nerve were done with superior, inferior, medial, and lateral approaches. The chi-square test and exact test were used to analyze the data and p-value < 0.05 was considered significant. Pre- and post-operative recurrent laryngeal nerve evaluation was done with 90 degrees Hopkins laryngoscope.

RESULTS

Overall in this series, the incidence of post-thyroidectomy RLNI was 3.7% and 3.7% for permanent and temporary nerve insults, respectively. Non-recurrent RLN on the right side was identified in one case and extra-laryngeal branching of RLN was identified in two cases. There was no statistically significant difference (p = 0.929) between the different approaches taken and the incidence of RLNI. The type of surgery and pathology also expressed no statistically significant relevance with the incidence of RLNI (p = 0.463 and p = 0.277, respectively).

CONCLUSION

Adoption of a particular surgical approach to localize and identify RLN during thyroid surgery carries no statistically significant difference between RLNI and approaches taken. Meticulous handling and dissection of the tissue in the correct surgical plane are crucial determinants in preventing RLNIs.

Relationship of Recurrent Laryngeal Nerve with Inferior Horn of Thyroid Cartilage, Berry's Ligament and Zuckerkandl's Tubercle

During neck surgery; Zuckerkandl's tubercle, Berry's ligament, the inferior horn of thyroid cartilages have become crucial anatomical landmarks in order to protect the integrity of the recurrent laryngeal nerve. Forty-two male postmortem human cadavers were used. The proximal part of the recurrent laryngeal nerve, before the inferior thyroid artery arises from its source has been observed in 87% inside the tracheoesophageal groove and in 13% running laterally to the trachea. The recurrent laryngeal nerve was encountered passing behind and through the branches of the inferior thyroid artery in 92% and 8% respectively. At all sides; the nerve was piercing the larynx 0.6 ± 0.1 mm below the inferior horn of thyroid cartilage, passing next to the inner-lower side of Berry's ligament and running under the lower middle part of Zuckerkandl's tubercle. These landmarks and their upper mentioned distances to the laryngeal nerve can be taken into consideration as important surgical guides.

Is craniocaudal dissection of recurrent laryngeal nerve safer than lateral approach: a prospective randomized study comparing both techniques by using continuous intraoperative nerve monitoring

Purpose

This study was performed to compare the real-time electromyographic (EMG) changes and the rate of recurrent laryngeal nerve (RLN) injury in craniocaudal and lateral approaches for RLN during thyroidectomy.

Methods

One hundred twelve and 86 patients were prospectively randomized to receive lateral (group 1) or craniocaudal (group 2) approach to RLN, respectively, under continuous intraoperative nerve monitoring.

Results

Loss of signal (LOS) occurred in 7 (2.0%) of 356 nerves at risk (NAR). LOS was significantly associated with repeated adverse EMG changes and presence of RLN entrapment at the ligament of Berry (LOB), which was accompanied by other clinicopathological or anatomical features, such as tubercle of Zuckerkandl (TZ), extralaryngeal branching, hyperthyroidism, autoimmune thyroid disease (ATD), or thyroid lobe volume of >29 cm³ (P = 0.001 and P = 0.030, respectively). The rate of repeated adverse EMG changes and LOS in the NARs with LOB entrapment accompanied by other clinicopathological and anatomical features was higher in group 1 vs. group 2 (11.1% vs. 2.2%, respectively and 9.7% vs. 0%, respectively; P = 0.070). The total rate of vocal cord palsy (VCP) was significantly higher in group 1 than in group 2 (P = 0.005). The rate of permanent VCP showed no significant difference between the 2 groups.

Conclusion

The craniocaudal approach to the RLN is safer than the lateral approach in the RLNs with entrapment at the LOB accompanied by other features, such as TZ, extralaryngeal branching, hyperthyroidism, ATD, or high thyroid lobe volume.

Improving Voice Outcomes after Thyroid Surgery and Ultrasound-Guided Ablation Procedures

The field of endocrine surgery has expanded from the traditional open neck approach to include remote access techniques as well as minimally invasive approaches for benign and malignant thyroid nodules. In experienced hands and with careful patient selection, each approach is considered safe, however complications can and do exist. Post-operative dysphonia can have serious consequences to the patient by affecting quality of life and ability to function at work and in daily life. Given the significance of post-procedural dysphonia, we review the surgical and non-surgical techniques for minimizing and treating recurrent laryngeal nerve injury that can be utilized with the traditional open neck approach, remote access thyroidectomy, or minimally invasive thermal ablation.

Anterolateral approach for thyroid swellings: impact on postoperative voice outcomes

Background

The sternothyroid muscle (ST) is routinely divided during grossly enlarged thyroid surgery to facilitate gland exposure. However, the ST is considered to play a role in controlling of pitch in the human voice. In this prospective cohort study, we described an anterolateral approach (AA) by which it was easy to expose the enlarged gland while preserving the ST, and evaluated the impact of this approach on vocal outcomes after total thyroidectomy.

Methods

The AA was performed on eligible patients from October 2018 to January 2020 in our department. Consecutive cases hospitalized from March 2020 and followed up to June 2021 who received total thyroidectomy via the midline approach (MA) served as controls. All participants underwent voice analysis before the operation and at 2 weeks and 3 months after the surgery. In 26 patients from AA group, strap muscles were mobilized along the anterior margin of both sternocleidomastoid muscles (SCMs) until 3 cm above the sternal notch followed by thyroidectomy, and their voice outcomes were compared to those of 36 patients from the MA group with a bilateral division of ST.

Results

Distribution of age, gender, specimen size, thyroid histopathology and laryngeal nerve identification rates did not differ significantly between groups. At 2 weeks post-surgery, objective assessment of voice change rate indicated no significant difference between groups, whereas the difference appeared to be partially manifest 3 months later. In the single-arm study, the AA group showed a decrease of maximum and fundamental pitch frequency 2 weeks after surgery but showed no difference in fundamental frequency after 3 months. The MA group continued to show a mild decrease in maximum and fundamental frequency at 3 months after surgery.

Conclusions

The AA affords sufficient visualization of the superior thyroid vessels and external branch of the superior laryngeal nerve (EBSLN) without sacrificing the integrity of the strap muscles. This approach is a feasible solution for selective difficult thyroid surgery and could reduce the postoperative changes in pitch of voice.

Anatomical Variations in Recurrent Laryngeal Nerves in Thyroid Surgery

OBJECTIVE

To study terminal bifurcation of recurrent laryngeal nerves (RLNs) with original direction to larynx entry and to decrease the risk of vocal cord paralysis in thyroid patients.

METHODS

The RLNs of 294 patients (482 sides) were dissected according to the branches into the larynx, and the original direction of each RLN trunk in thyroid surgery was recorded.

RESULTS

(1) About 30.9% of the RLNs gave off multiple branches into the larynx. (2) Two and 3 branches of RLNs into the larynx were found in 25.5% and 5.4% of the cases, respectively. (3) In 0.4% or 2 cases, the RLN trunk combined with the inferior branch of the vagus nerve. (4) Nonrecurrent laryngeal nerve appeared in 2 cases. (5) On the left side, 68.0%, 25.6%, and 6.4% of cases were found with 1, 2, and 3 bifurcations of RLN to larynx entry, respectively. On the right side, 69.8%, 25.8%, and 4.4% cases were identified with 1, 2, and 3 bifurcations of RLN to larynx entry, respectively. (6) The combining dissection approach was proved as successful and safe for protecting the RLN with no permanent RLN paresis.

CONCLUSIONS

Because of the anatomical variation in RLNs with extralaryngeal bifurcation, it is necessary to increase the awareness of surgeons about these variations so as to protect bifurcated nerves in thyroid surgery.

Superior Approach of Recurrent Laryngeal Nerve: Review of the Literature

The identification and dissection of the recurrent laryngeal nerve is essential to guarantee its anatomical and functional integrity. The superior approach of the recurrent nerve is a reliable surgical alternative. Various indications are recognized with a reliable landmark. This is the entry point into the larynx under the inferior horn of the thyroid cartilage. The limits of this technique, namely, the extralaryngeal divisions and the hemorrhages encountered at the point of entry of the larynx are a source of morbidity of the recurrent laryngeal nerve. A careful dissection, respect for the surgical steps, and the surgeon's experience are guarantees of a good result. We wanted through a review of the literature and our experience in the superior approach to discuss surgical indications, to identify landmarks at the point of entry of the larynx, to determine the limits of this approach, and to take precautions to mitigate the risk of recurrent laryngeal nerve injury.