Bilateral Neck Exploration May Not Reduce the Risk of Persistence but Shows a Perspective Advantage
Authors: Buzanakov Dmitrii , Sleptsov Ilya , Semenov Arseny , Chernikov Roman , Novokshonov Konstantin , Karelina Julia , Makarin Viktor , Uspenskaya Anna , Chinchuk Igor , Gorskaya Natalya , Timofeeva Natalya , Malugov Yuri , Fedorov Elisey , Sablin Ilya , Alekseeva Svetlana , Pridvizhkina Tatyana , Borisenko Tatyana , Dzhumatov Timur , Gerasimova Ksenya , Zolotukho Anna , Pushkaruk Alexander , Bubnov Alexander 
Published: May 2021

Abstract
There is still no consensus for an optimal surgical treatment of primary hyperpararthyroidism (PHPT). Virtually, most of the patients could be successfully treated with the selective parathyroidectomy (SPTE) based on preoperative visualization. However, this approach still has a “blind area” of undetected multiglandular disease (MGD). Bilateral neck exploration (BNE) may serve as a reasonable alternative but it meets the higher requirements for the surgical technique. A retrospective cohort study was conducted in order to reveal factors associated with the persistence of PHPT. 587 cases of PHPT patients who had received surgical treatment at SPSU Hospital in 2017–2018 were included. All the patients have at least one preoperative visualization study (neck ultrasound performed by a surgeon) before the operation. In 356 cases two studies were performed (additional 4D CT or MIBI scan) and 116 cases had all three. A surgeon was free to choose a type of the operation (selective or explorative) according to their strategic preferences. Bilateral neck exploration was performed in 160 cases. There was no difference in bilateral exploration rate (p = 0.3896) between the groups (with 1, 2 or 3 studies performed) indicating that the additional visualization does not allow to avoid bilateral exploration. MGD rate accounted for 7.4% (40 cases). It is important that any set of preoperative visualization modalities prove the absence of MGD reliably and select patients for SPTE precisely. Negative predictive value for different combinations of concordant studies (US+MIBI, US+CT and US+CT+MIBI) did not differ significantly and was 96.95%, 97.4% and 97.7% respectively. 26 cases of persistent disease were reported with no significant difference between BNE and SPTE groups. (6 vs 20 respectively, p = 0.792). A history of the thyroid or parathyroid operations was found to be the only factor predicting the higher risk of persistence (OR = 7.98; 95% CI [2.62 - 24.27]), while neither the number of parathyroid glands found during the surgery nor the number of preoperative visualization studies showed statistical significance. Only 47,5% cases of BNE was reported to have all four glands visualized. There rate of failure to found each gland was similar. Surprisingly, the superior parathyroid adenomas (P4) were more likely to be removed (chi-squared 10.378, p = 0.0006) but not in the cases with all four glands visualized intraoperatively (chi-squared 1.822, p = 0.0884). The true rate difference due to a hypothetical feature of parathyroid physiology seems to be not very likely. One may rather suggest than it is not an uncommon for a surgeon to identify a P3 gland as a P4 unless all for glands are visualized. This fact shows a perspective advanantage which may prevent some cases of persistence.