Following the division of the isthmus, the edge on the resection side is grasped with Babcock forceps, placing it on lateral traction. The thyroid gland is then separated from the cricothyroid muscle and the trachea medially, leaving the berry's suspensory ligament adjacent to the first tracheal ring intact. The avascular space between the superior pole and the cricothyroid muscle is open. Finally, in the most critical step, the berry's ligament lateral to the first tracheal ring is placed on differential traction using two retractors - facilitating careful identification of the RLN as it courses under the superior edge of the berry's ligament - entering the larynx beneath the cricopharyngeus muscle. The RLN is identified at its most distal and consistent location as it enters the larynx.

In the lateral approach group, the superior thyroid pedicle is mobilized and ligated, followed by medial rotation of the thyroid gland with division of the middle thyroid vein. Then, the RLN is identified in between the tubercle of Zuckerkandl and the cricothyroid joint. Berry's suspensory ligament is then divided. The thyroid lobe will then be completely dissected from the trachea as the final step in lobectomy.

Medial vs Lateral Approach to RLN during thyroidectomy

1. LOS - as defined by a decline of amplitude to <100uV as measured by CIONM
2. Combined adverse events - an event wherein both 50% reduction in EMG amplitude and 10% latency are observed on CIONM

1. Temporary hypocalcemia - ionized calcium <1.0 mmol/L on post operative day 1 OR any requirement for calcium AND vitamin D supplementation for 6 months or less post surgery
2. Permanent hypocalcemia - any hypocalcemia requiring calcium AND vitamin D supplementation for over 6 months post surgery