The Value of Intraoperative Ultrasound in Selective Lateral Cervical Neck Lymphadenectomy for Papillary Thyroid Cancer: A Prospective Pilot Study

SIMPLE SUMMARY: Selective neck dissection is currently accepted as the standard of care for lateral cervical nodal disease from papillary thyroid cancer. However, the clinical intraoperative detection of metastatic nodal involvement may be challenging, especially in difficult-to-spot neck levels behind the sternocleidomastoid muscle, and hinges on imaging investigations. In this respect, the significance of diagnostic intraoperative US in metastatic papillary thyroid cancer seems to be under-investigated in literature. We ran a prospective diagnostic study where an intraoperative ultrasound (IOUS) showed increased sensitivity for the detection of lateral neck nodes with respect to preoperative US scans, especially in the difficult-to-spot neck levels: in sublevels such as IIb and V, up to one quarter of patients examined had nodes newly detected by IOUS that were confirmed at pathology. This study offers evidence that IOUS may provide accurate intraoperative node mapping, supporting precise and more reliable selective neck dissection. ABSTRACT: (1) Background: Lymph node metastases from papillary thyroid cancer (PTC) are frequent. Selective neck dissection (SND) is indicated in PTC with clinical or imaging evidence of lateral neck nodal disease. Both preoperative ultrasound (PreUS) and intraoperative palpation or visualization may underestimate actual lateral neck nodal involvement, particularly for lymph-nodes located behind the sternocleidomastoid muscle, where dissection may also potentially increase the risk of postoperative complications. The significance of diagnostic IOUS in metastatic PTC is under-investigated. (2) Methods: We designed a prospective diagnostic study to assess the diagnostic accuracy of IOUS compared to PreUS in detecting metastatic lateral neck lymph nodes from PTC during SND. (3) Results: There were 33 patients with preoperative evidence of lateral neck nodal involvement from PTC based on PreUS and fine-needle cytology. In these patients, IOUS guided the excision of additional nodal compartments that were not predicted by PreUS in nine (27.2%) cases, of which eight (24.2%) proved to harbor positive nodes at pathology. The detection of levels IIb and V increased, respectively, from 9% (PreUS) to 21% (IOUS) (p < 0.0001) and from 15% to 24% (p = 0.006). (4) Conclusions: In the context of this study, IOUS showed higher sensitivity and specificity than PreUS scans in detecting metastatic lateral cervical nodes. This study showed that IOUS may enable precise SND to achieve oncological radicality, limiting postoperative morbidity.