Clinical significance of retrograde inferior parathyroid protection technique based on thymus preservation in thyroid surgery

Clinical significance of retrograde inferior parathyroid protection technique based on thymus preservation in thyroid surgery | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Clinical significance of retrograde inferior parathyroid protection technique based on thymus preservation in thyroid surgery Shouyi Yan, Yuhan Chen, Wenxin Zhao, Liyong Zhang, Shaojun Cai This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4935264/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 26 Jan, 2025 Read the published version in BMC Endocrine Disorders → Version 1 posted 4 You are reading this latest preprint version Abstract Background The importance of parathyroid gland protection has been widely recognized in thyroid surgery. However, it remains difficult to quickly identify parathyroid gland, especially the inferior parathyroid gland (IPG). This study aimed to evaluate the effectiveness of retrograde inferior parathyroid protection technique (RIPPT) based on thymus preservation. Methods A total of 236 patients was enrolled in this study from August 2019 to December 2020. We used RIPPT to identify and protect inferior parathyroid gland (IPG), followed by analyzing its identification rate and anatomical types of IPG. Thereafter, we compared the parathyroid hormone (PTH) and serum calcium level of IPG orthotopic retention patients with that of IPG auto-transplantation patients among different IPG anatomical types. Results In all cases, the rate of IPG identification and auto-transplantation was 97.88% (231/236) and 74.46% (172/231) respectively. The proportion of patients with an anatomical relationship between the IPG and thymus was 77.97% (184/236). Furthermore, we found that PTH level in patients with IPG orthotopic retention was higher than that in those with IPG auto-transplantation in 1 day or 6 months after surgery; PTH level was also found higher in patients with superior parathyroid gland (SPG) and IPG orthotopic retention than the ones receiving both auto-transplantation. Conclusion Retrograde inferior parathyroid protection technique (RIPPT) argues for the primacy of the protection concept of inferior parathyroid gland (IPG) in thyroid surgery, and is proven to be effective in the rapid identification and functional protection of IPG based on short-term data. Inferior parathyroid gland Papillary thyroid cancer Thymus-related inferior parathyroid gland Thyroid surgery Retrograde inferior parathyroid protection technique Thymus preservation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Thyroid papillary cancer (PTC) was the most common endocrine malignancy. The incidence rate of PTC has been increasing over the past 30 years[ 1 ][ 2 ] and its main treatment was surgery. The surgical intention was to quickly identify the recurrent laryngeal nerve (RLN) and PG to avoid vocal cord paralysis and hypoparathyroidism[ 3 ][ 4 ], the latter can lead to patient’s osteoporosis, numbness of the hands and feet etc.[ 5 ][ 6 ] As technology develops, finding RLN has become easier with the help of intraoperative neuromonitoring (IONM)[ 7 ][ 8 ]. In terms of parathyroid glands, improvement in PG protection is still strongly needed. It was known that the anatomic location of the SPG was fixed at the dorsal side of the upper pole of the thyroid lobe, at which the level of the inferior border of the cricoid cartilage settled. However, the location of IPG was variable due to its embryologic relations to the thymus[ 9 ]. Ordinarily, the keys to PG identification were its light brown color, its texture and micro vessels on PG’s surface[ 10 ]. To identify PG, most surgeons rely on the its anatomical location and characteristics, sometimes with the help of Nano carbon[ 11 ]; but there are still many difficulties in PG identification, especially IPG. The Chinese guideline had reported the correlations between the PG and thyroid gland[ 12 ], but it was not helpful in rapid IPG searching during surgery, especially when IPG was wrapped by the thymus. Also, the traditional way of searching for IPG was easily affected by various factors such as surgical experience, obesity, PG fatty degeneration and intraoperative bleeding[ 13 ][ 14 ]. PG fluorescence technology can help to identify PG during surgery despite disadvantages like defective recognition effect, obesity limitation and time-consuming[ 15 ], making the technology difficult to popularize in primary hospitals. As far as we knew, the IPG and thymus were closely related to each other during the development of embryonic tissues[ 16 ]. Thus, we propose the hypothesis that RIPPT can improve IPG’s identification and orthotopic retention rates. Methods Patients Characteristics A total of 236 continuous patients were enrolled from August 2019 to December 2020 in this prospective single-arm study. The inclusion criteria were as below: All the patients were diagnosed as unilateral PTC by preoperative fine needle aspiration with the longest PTC diameter under 4cm. Patients with any of the following conditions will be excluded: tumor having invaded IPG and surrounded tissue; having a history of thyroid surgery or less than 16 years old or unavailable for the follow-up protocols; metastatic lymph nodes found in the preoperative examination. General characteristics, intraoperative factors, pathological examination, the number of total LNs and metastatic LNs in the resected specimens, and postoperative complications were collected retrospectively. The main observation was the rates of SPG and IPG recognition, orthotopic retention, auto-transplantation, serum calcium level, and PTH levels in both hands. All the patients had the operation of thyroid lobectomy plus dissection of the central lymph node, which was performed by the same surgeon. IPG types According to the relationship between the IPG and thymus and its location, IPG was classified into five types (Fig. 1 ). Type A: within the thymus (Fig. 1 A); Type B: at the top of the thymus (Fig. 1 B); Type C: extremely near the top of the thymus, where the distance was equal to or less than 5mm (Fig. 1 C); Type D: near the top of the thymus, but the distance was more than 5mm (Fig. 1 D); Type E: anatomically irrelevant with thymus or IPG was attached to the thyroid (Fig. 1 E). Surgical procedure of IPG identification by RIPPT Initially, the lateral side of the thyroid gland was separated to expose the common carotid sheath from the upper pole of the thyroid to the thymus. The thyroid gland was then pulled to the contralateral side for the convenience of IPG observation. Next, we pulled the thyroid gland and observed the IPG in the lower part of the thyroid gland (Fig. 2 ). If the IPG was attached closely to the thyroid or difficult to be retained in situ, then timely auto-transplantation was mandatory. Employing the previous method[ 17 ], we later exposed the RLN quickly and found the thymus which would be separated to its top from the caudal to the cephalic direction (Fig. 3 ). During this process, we might find the IPG within the thymus or at the top of the thymus (Fig. 4 ). Simultaneously, IPG and thymus could be in situ reserved as a whole (Fig. 5 ). However, IPG was wrapped by the thymus in some patients, making it difficult to be identified (Fig. 6 ). In this case, we continued to separate the thyroid thymus ligament along the thyroid. Generally, IPG can be found within 10 mm from the top of thymus. If IPG was 10 mm further from the top of thymus or IPG was found with no blood supply, IPG auto-transplantation into the brachioradialis muscle of the left forearm was needed promptly because existing studies had shown that PG auto-transplantation could preserve its function[ 18 ]. In all the patients, the suspected parathyroid tissue was punctured 3–5 times with a 1ml needle (Fig. 7 ), and then the needle was thoroughly rinsed in 1ml saline. Finally, the PTH rapid test paper combined with the dropping of 100ul of eluent was applied to detect whether the suspected tissue was parathyroid. The testing result was observed 5 mins later, with a certain color for positive and no color for negative (Fig. 8 ) Subsequently, we continued to perform thyroidectomy and central lymph node dissection according to China’s thyroid guidelines[ 19 ][ 20 ]. If the IPG was not found during the procedure mentioned above, searching for IPG in the excised specimen was indispensable. Follow-up and postoperative treatment of hypoparathyroidism All patients were accompanied by 12–20 months of following up. The PTH level and serum calcium level were tested in 1 day, 2 months, and 6 months after surgery. When PTH level was under 1.3mmol/L six months after surgery, postoperative hypoparathyroidism was confirmed. Levothyroxine treatment was necessary for all patients after surgery. Calcium supplementation and vitamin D were prescribed before the PTH level of patients with symptomatic hypoparathyroidism reaching normal. Intravenous substitution therapy of calcium was adopted in the case of serious symptomatic hypocalcemia. Statistical analysis Statistical analysis was performed by SPSS 26.0, Chicago, IL, USA. All data was presented as mean ± standard deviation. Comparisons between the two groups were conducted by independent sample T-test or Chi-Square test, requiring P < 0.05 was statistically significant. P values are represented as P < 0.05, no significance and P ≥ 0.05. Results Patient characteristics: IPG anatomical types, SPG and IPG recognition, orthotopic retention, auto-transplantation. The overall proportion of patients showing a positive anatomical association between the IPG and thymus was 79.65% (184/231), and the specific distributions of IPG anatomic type were as follows: Type A, 11.69% (27/231); Type B, 11.69% (27/231); Type C, 23.38% (54/231); Type D, 32.9% (76/231); and Type E, 20.35% (47/231). Their corresponding IPG orthotopic retention rate were 100% (27/27), 92.59% (25/27), 20.37% (11/54), 0% (0/76), and 0% (0/47) respectively. Among the patients with IPG Type E, 35/47 patients had an IPG closely attached to the thyroid surface, and only 12/47 patients required a careful search of the IPG in the resected specimens. The SPG identification and auto-transplantation rate was 100% (236/236) and 8.47% (20/236), while IPG identification and auto-transplantation rate was 97.88% (231/236) and 74.46% (172/231), respectively. The rate of one or two PG auto-transplantation was 67.80% (160/236) and 6.8% (16/236). The overall PG survival rate was 86.36% (152/176). However, PG survival rate significantly differed by the number of PG being auto-transplanted, as one PG is 85% and two is 100%. We also found the patients’ right-hand and the left-hand PTH level from two PG auto-transplantation group were both higher than those from one PG auto-transplantation group in 2 months and 6 months after surgery. (Table 1 ) Table 1 PTH level and survival rate of PG in the patients with different numbers of PG auto-transplantation Variable Time points of postoperative review One IPG auto-transplantation Two IPG auto-transplantation P value Right-hand PTH level pre-operation 3.95 ± 1.52 4.3 ± 1.98 0.092 1 days after surgery 2.90 ± 1.36 2.57 ± 1.24 0.349 2 months after surgery 3.90 ± 1.81 2.86 ± 1.05 0.026 6 months after surgery 3.59 ± 1.56 3.38 ± 1.12 0.587 Left-hand PTH level 6 months after surgery 23.46 ± 12.54 35.46 ± 20.65 0.045 Survival rate of PG auto-transplantation 6 months after surgery 122/176 (86.36%) 16/16 (100%) 0.007 The risk factors in the patients with IPG unidentified during the operation We found IPG in most patients during operation, but some IPG (5/236) were still missing. Meanwhile, our postoperative paraffin pathology results revealed that there were 15 patients with accidental removal of IPG, except the previous five cases. We suspect the IPG found in postoperative paraffin specimens may be the fifth PG. Further analysis also showed the IPG unidentified was mainly related to the age(P = 0.013), but not associated with IPG anatomical type, body mass index, tumor size, total numbers of lymph nodes, numbers of lymph node metastases, diabetes, hypertension, or thyroid disease. (Table 2 ) Table 2 The risk factors in the patients with IPG unidentified during the operation Variable IPG identified 231 cases IPG unidentified 5 cases Chi-square or T value P value Age 45.06 ± 11.14 57.06 ± 9.76 -2.496 0.013 Tumor side 106/125 1/4 / 0.381 Body mass index (Kg/m2) 23.00 ± 2.69 22.59 ± 5.54 0.165 0.877 Years(≤ 55y/>55y) 189/42 3/2 / 0.234 Sex (Male/Female) 58/173 1/4 / 1.000 Total numbers of lymph nodes 9.42 ± 8.14 8.6 ± 2.88 0.223 0.824 Numbers of lymph node metastases 1.09 ± 1.99 0.60 ± 1.34 0.544 0.587 Diabetes 18/231 1/5 / 0.345 Hypertension 30/231 2/5 / 0.137 Thyroid disease (Hashimoto or nodular goiter) 194/231 3/5 / 0.192 Comparison of serum PTH and calcium level between patients with different characteristics We found that PTH level of patients with IPG orthotopic retention was higher than that of patients with IPG auto-transplantation; however, this difference was only found at 1 day and 6 months after surgery. Nevertheless, there was no statistical difference in serum calcium levels between the two groups after surgery. (Table 3 ) Table 3 The PTH and serum calcium level between the patients with IPG orthotopic retention and auto-transplantation after surgery. Variable IPG orthotopic retention IPG auto- transplantation Chi-square value P value PTH (pre-operation) 3.98 ± 1.30 4.00 ± 1.58 -0.074 0.941 PTH (1 days after surgery) 3.36 ± 1.31 2.89 ± 1.36 2.424 0.016 PTH (2 months after surgery) 3,82 ± 1.12 3.83 ± 1.79 -0.041 0.968 PTH (6 months after surgery) 4.18 ± 1.47 3.57 ± 1.52 2.767 0.006 Ca (pre-operation) 2.34 ± 0.07 2.35 ± 0.17 -0.185 0.853 Ca (1 days after surgery) 2.21 ± 0.10 2.19 ± 0.10 1.268 0.206 Ca (2 months after surgery) 2,39 ± 0.11 2.38 ± 0.11 0.448 0.654 Ca (6 months after surgery) 2.42 ± 0.35 2.35 ± 0.10 1.678 0.098 We further analyzed the PTH level and serum calcium level in 3 types of IPG orthotopic retention and found them with no statistical difference in the single factor analysis of variance in three-time nodes after surgery. Neither was there any difference in PTH and serum calcium level in further comparisons between any two groups. (Table 4 ) Table 4 The PTH and serum calcium level among the patients with different IPG type of orthotopic retention Variable IPG type of orthotopic retention F value P value Type A Type B Type C PTH (pre-operation) 3.64 ± 1.07 4.33 ± 1.61 3.88 ± 0.90 1.577 0.204 PTH (1 days after surgery) 3.35 ± 1.38 3.44 ± 1.44 3.30 ± 0.88 0.138 0.937 PTH (2 months after surgery) 3.83 ± 1.08 3.87 ± 1.21 3.68 ± 1.20 0.074 0.974 PTH (6 months after surgery) 4.04 ± 1.28 4.24 ± 1.53 4.38 ± 1.94 0.203 0.894 Ca (pre-operation) 2.34 ± 0.06 2.36 ± 0.07 2.31 ± 0.08 1.339 0.270 Ca (1 days after surgery) 2.19 ± 0.10 2.23 ± 0.10 2.20 ± 0.08 1.136 0.342 Ca (2 months after surgery) 2.38 ± 0.10 2.40 ± 0.12 2.40 ± 0.11 0.306 0.821 Ca (6 months after surgery) 2.35 ± 0.12 2.39 ± 0.10 2.37 ± 0.07 0.641 0.591 We also found that the PTH level in patients with SPG and IPG orthotopic retention was significantly higher than that in patients with SPG and IPG auto-transplantation at the three-time node after surgery. However, there was no statistical difference in the serum calcium level between them at the three-time node after surgery. (Table 5 ) Table 5 the differences of the PTH and serum calcium level between the patients with SPG and IPG orthotopic retention or not (SPG and IPG auto-transplantation) variable SPG and IPG orthotopic retention SPG and IPG auto-transplantation Chi-square value P value PTH (pre-operation) 4.02 ± 1.33 4.30 ± 1.98 -0.546 0.592 PTH (1 days after surgery) 3.44 ± 1.29 2.57 ± 1.24 2.422 0.018 PTH (2 months after surgery) 3.90 ± 1.10 2.86 ± 1.05 3.388 0.001 PTH (6 months after surgery) 4.23 ± 1.44 3.37 ± 1.12 2.203 0.031 Ca (pre-operation) 2.34 ± 0.07 2.28 ± 0.31 0.871 0.397 Ca (1 days after surgery) 2.21 ± 0.09 2.19 ± 0.07 0.943 0.349 Ca (2 months after surgery) 2.38 ± 0.11 2.34 ± 0.11 1.121 0.266 Ca (6 months after surgery) 2.37 ± 0.10 2.31 ± 0.10 0.712 0.053 Side effects and operative complications Some patients encountered complications including postoperative bleeding (1/236), transient hypoparathyroidism (3/236) and transient recurrent laryngeal nerve palsy (6/236). Patients with transient hypoparathyroidism showed no low-calcium symptoms and PTH level reached normal after two weeks. Also, patients with transient vocal cord dyskinesia recovered after 2 months according to electronic laryngoscope. Discussion In this study, a new strategy was used to search IPG by RIPPT and results showed IPG identification and auto-transplantation rate was 97.88% and 74.46% respectively. Meanwhile, the proportion of identified and transplanted IPG was higher than that recorded in previous literature[ 21 ][ 22 ][ 23 ]. The proportion of patients with anatomical relationship between IPG and thymus was 77.97% (184/236), and the survival rate of one PG and two PG auto-transplantation was 85% and 100% respectively. The result mentioned above indicated that there was an anatomical relationship between IPG and thymus for most patients, even with 5/236 IPG unidentified and 15/236 IPG accidental removal. The theoretical basis lies in the embryonic development relationship between IPG and thymus, as well as the simplicity and feasibility of thymus identification during surgery by RIPPT. RIPPT did help to find the IPG quickly, but it was uncertain whether IPG orthotopic retention was beneficial to its functional protection. In this study, we found PTH level of patients with IPG orthotopic retention was significantly higher than that of patients with IPG auto-transplantation at 1 day and 6 months after surgery. However, we did not observe differences in the PTH and serum calcium levels among the 3 IPG anatomical types with orthotopic retention, and this result might be due to our clinical decision of IPG auto-transplantation. We choose IPG orthotopic retention when we were confident with its blood supply. Otherwise, we would choose IPG auto-transplantation. Meanwhile, the question that whether auto-transplantation or orthotopic retention should be chosen to protect IPG well when IPG has been found could be explained by our data revealing elevated PTH level of patients with SPG and IPG orthotopic retention versus the one with both auto-transplantation. More importantly, RIPPT not only increases the efficiency of IPG protection but also reduces the difficulty of thyroid surgical operation. During surgery, we separated the external side of the thyroid gland before searching for the thymus, dealing with the middle and lower thyroid veins on the superficial surface of the common arterial sheath, so as not to cause bleeding which could affect surgical field; Then, we found and protected RLN quickly, avoiding damage in the process of IPG searching according to our previous method; Moreover, we advocated the priority of IPG protection and IPG orthotopic retention, but auto-transplantation should be carried out timely when IPG could not be preserved in situ; Finally, complete the surgery with the help of RIPPT could reduce the difficulty of LNs dissection and avoid RLN injury and PG midsection, on the premise that RLN and IPG had been protected. So RIPPT is simple and safe, especially suitable for surgeons lacking surgical experience. This study was only applicable to "thyroid cancer patients who receive unilateral/bilateral surgery", and the technique can be performed on the central neck dissection (CND) side. Additionally, as the indications for CND in the guidelines are gradually restricted, the indications of RIPPT will also be more limited. Wang JB reported the way of detecting blood supply to the IPG based on the "layer of thymus-blood vessel-inferior parathyroid gland" concept[ 24 ], and Wang X also used a novel meticulous thyrothymic ligament dissection technique to explore the inferior parathyroid gland. But their approach was more difficult to preserve the branches of the inferior thyroid artery, not advised to be popularized and recommended in the primary hospital[ 25 ]. Different from their surgical techniques, our study focused on searching IPG by RIPPT and decide whether IPG should be retained in situ according to IPG type. Since IPG in situ with blood supply from the thymus are more likely to survive, we chose the more aggressive auto-transplantation for patients with type D IPG and shortened the time of IPG searching to avoid its function impairment[ 26 ]. Although this technology was widely used in our hospital, it still remained some shortcomings that required to be improved as follows: 1. Further validation was needed for the blood supply or later microcirculation establishment in the IPG orthotopic retention; 2. The PTH level in this study was affected by the IPG auto-transplantation and contralateral PG compensation; 3. More IPG auto-transplantation was selected in the patients with type D IPG, so there was no comparison in the PTH level between the type C and D IPG, an active strategy of IPG situ retention with type D was needed for further validation. Conclusion The RIPPT technique emphasizes the primary concept of IPG protection during thyroid surgery. It is beneficial for rapid IPG searching and functional protection based on short-term data. Therefore, it might be a method worth popularizing to hospitals for protecting PG function. Abbreviations PTC papillary thyroid carcinoma RLN recurrent laryngeal nerve PG parathyroid gland SPG superior parathyroid gland IPG Inferior parathyroid gland PTH parathyroid hormone TC thyroid carcinoma IONM intraoperative neuromonitoring TRIPG thymus-related inferior parathyroid gland RIPPT retrograde inferior parathyroid protection technique LNs Lymph nodes Declarations Ethics approval and consent to participate The study was approved by the ethics committee of Fujian Medical University Union Hospital. (2019KY122) Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests Funding This study was supported by Joint Funds for the Innovation of Science and Technology, Fujian province (grant number: 2019KY122) and Clinical Research Center for Precision Management of Thyroid Cancer of Fujian Province (grant number: 2022Y2006) Author Contribution No editorial services were used for this manuscript. Wenxin Zhao contributed to the concept of study design and final approval of the work. Shouyi Yan contributed by writing and data analysis. Yuhan Chen contributed through the collection and analysisof data, preservation of original data, and preparation of the manuscript. Liyong Zhang contributed by review of data and analysis of data. Shaojun Cai contributed through data acquisition. All authors read and approved the final manuscript. Acknowledgement All contributors of this manuscript are named co-authors. Shouyi Yan and Yuhan Chen are named co-first authors. Wenxin Zhao is named corresponding author. No other acknowledgments are applicable. Availability of data and materials The datasets generated and/or analyzed during the current study are not publicly available due to the complexity and amount of data, which requires special processing software. However, data are available from the corresponding author on reasonable request. References Siegel RL, Miller KD, Goding Sauer A, Fedewa SA, Butterly LF, Anderson JC, Cercek A, Smith RA, Jemal A. Colorectal cancer statistics, 2020. Cancer J Clin. 2020;70(3):145–64. Cabanillas ME, McFadden DG, Durante C. Thyroid cancer. Lancet. 2016;388(10061):2783–95. Cirocchi R, Arezzo A, D’Andrea V, Abraha I, Popivanov GI, Avenia N, Gerardi C, Henry BM, Randolph J, Barczyñski M. Intraoperative neuromonitoring versus visual nerve identification for prevention of recurrent laryngeal nerve injury in adults undergoing thyroid surgery. Cochrane Database Syst Reviews (1) (2019). 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Cite Share Download PDF Status: Published Journal Publication published 26 Jan, 2025 Read the published version in BMC Endocrine Disorders → Version 1 posted Editorial decision: Revision requested 27 Aug, 2024 Editor assigned by journal 22 Aug, 2024 Submission checks completed at journal 22 Aug, 2024 First submitted to journal 18 Aug, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4935264","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":345545713,"identity":"8a5ad818-8aa4-465c-ae6c-ac4a4984bb8c","order_by":0,"name":"Shouyi Yan","email":"","orcid":"","institution":"Fujian Medical University Union Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shouyi","middleName":"","lastName":"Yan","suffix":""},{"id":345545718,"identity":"2967641d-a720-4781-ace2-dfb1fa81e3e0","order_by":1,"name":"Yuhan Chen","email":"","orcid":"","institution":"Fujian Medical University Union Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuhan","middleName":"","lastName":"Chen","suffix":""},{"id":345545723,"identity":"c20858d9-04f5-4929-afb3-3cf2335cde46","order_by":2,"name":"Wenxin Zhao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0klEQVRIiWNgGAWjYBAC9gYeEGUjx8/efODAhx9EaOE5ANaSZizZcyzx4Mwe4rUcSjS4kWN8mIONGC38Zw9/5m07kCDZc+bDYQYeBnl+sQMEtDCcSzDmOXMnj5+9d8PhAgsGw5mzE/BrsWfsMUjOqXhWLNlzdsPhGTwMCQa3CWjhYeYxOJxjcDhxw42cB4d52IjRwsZj2JxTAdbCQKQWHh5j5j9nwIFsAAxkCcJ+4eE/Y/xxZhs4Kh9/+PDDRp5fmoAWdCBBmvJRMApGwSgYBdgBAAPVSKoknbHaAAAAAElFTkSuQmCC","orcid":"","institution":"Fujian Medical University Union Hospital","correspondingAuthor":true,"prefix":"","firstName":"Wenxin","middleName":"","lastName":"Zhao","suffix":""},{"id":345545729,"identity":"ab6a86b4-3329-404f-87da-d8d486724dbc","order_by":3,"name":"Liyong Zhang","email":"","orcid":"","institution":"Fujian Medical University Union Hospital","correspondingAuthor":false,"prefix":"","firstName":"Liyong","middleName":"","lastName":"Zhang","suffix":""},{"id":345545732,"identity":"79efa732-3658-4658-92de-44e0c9cebbde","order_by":4,"name":"Shaojun Cai","email":"","orcid":"","institution":"Fujian Medical University Union Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shaojun","middleName":"","lastName":"Cai","suffix":""}],"badges":[],"createdAt":"2024-08-19 02:06:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4935264/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4935264/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12902-025-01838-y","type":"published","date":"2025-01-26T15:58:26+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":66743721,"identity":"582e5137-aed8-47bd-9756-598cf6deac5e","added_by":"auto","created_at":"2024-10-16 06:10:02","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":100998624,"visible":true,"origin":"","legend":"\u003cp\u003eIPG classifications: Type A to Type E\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/181c471dc0400e762ded24dc.jpg"},{"id":66743717,"identity":"ba7c61be-cb62-46c0-8fcc-e36ddc142066","added_by":"auto","created_at":"2024-10-16 06:10:01","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":858358,"visible":true,"origin":"","legend":"\u003cp\u003eWe pulled the thyroid gland to the contralateral side and observed the IPG in the lower part of the thyroid gland\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/3db7e0a0961f17c9b6d18482.png"},{"id":66743719,"identity":"32455798-149e-45e0-b35a-88ff6e75cb41","added_by":"auto","created_at":"2024-10-16 06:10:01","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1502422,"visible":true,"origin":"","legend":"\u003cp\u003eWe found the thymus and separated it from the tail to head side\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/0347f4d289426d7abc9b9d59.png"},{"id":66743714,"identity":"c0b13228-8cf3-4aca-845b-7b06175ea843","added_by":"auto","created_at":"2024-10-16 06:10:00","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1682008,"visible":true,"origin":"","legend":"\u003cp\u003eWe found that the IPG was located within the top of the thymus.\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/f3fa3d8cdeb49331e8b6ec64.jpg"},{"id":66744475,"identity":"c5ef2b86-82f9-403f-9460-0d25012127ed","added_by":"auto","created_at":"2024-10-16 06:18:01","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1879844,"visible":true,"origin":"","legend":"\u003cp\u003eIPG and thymus could be situ reservation as an organic whole\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/9cb2cba5464fa8c278b33467.png"},{"id":66743716,"identity":"7a1431cc-758b-4474-bbbb-c32bd829212f","added_by":"auto","created_at":"2024-10-16 06:10:01","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1700597,"visible":true,"origin":"","legend":"\u003cp\u003eIPG was wrapped by thymus, which was difficult to be identified directly and clearly by\u003c/p\u003e\n\u003cp\u003enaked eye unless we open the capsule of the thymus\u003c/p\u003e","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/db07ce5350b1ab086a4f27eb.png"},{"id":66743715,"identity":"e66ae489-554c-4df3-8823-1714aecd7a3a","added_by":"auto","created_at":"2024-10-16 06:10:01","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":1313439,"visible":true,"origin":"","legend":"\u003cp\u003eThe suspected parathyroid tissue was punctured 3-5 times with a 1ml needle\u003c/p\u003e","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/0f9a7c926dc3106c277664e6.png"},{"id":66744476,"identity":"627a2797-09e1-4c4e-b8e0-d69a860eb350","added_by":"auto","created_at":"2024-10-16 06:18:01","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":1593892,"visible":true,"origin":"","legend":"\u003cp\u003eWhen the parathyroid tissue was confirmed, the reaction line would display\u003c/p\u003e","description":"","filename":"Figure8.png","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/b2772827257bfb3784d82a5b.png"},{"id":74858564,"identity":"c17de52f-8870-44c7-97f2-e3b2612b024d","added_by":"auto","created_at":"2025-01-27 16:11:36","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":118273459,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4935264/v1/8175d7cb-15a6-418a-8513-536158dd45db.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Clinical significance of retrograde inferior parathyroid protection technique based on thymus preservation in thyroid surgery","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThyroid papillary cancer (PTC) was the most common endocrine malignancy. The incidence rate of PTC has been increasing over the past 30 years[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e][\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] and its main treatment was surgery. The surgical intention was to quickly identify the recurrent laryngeal nerve (RLN) and PG to avoid vocal cord paralysis and hypoparathyroidism[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e][\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], the latter can lead to patient\u0026rsquo;s osteoporosis, numbness of the hands and feet etc.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e][\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] As technology develops, finding RLN has become easier with the help of intraoperative neuromonitoring (IONM)[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e][\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In terms of parathyroid glands, improvement in PG protection is still strongly needed.\u003c/p\u003e \u003cp\u003eIt was known that the anatomic location of the SPG was fixed at the dorsal side of the upper pole of the thyroid lobe, at which the level of the inferior border of the cricoid cartilage settled. However, the location of IPG was variable due to its embryologic relations to the thymus[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Ordinarily, the keys to PG identification were its light brown color, its texture and micro vessels on PG\u0026rsquo;s surface[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. To identify PG, most surgeons rely on the its anatomical location and characteristics, sometimes with the help of Nano carbon[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]; but there are still many difficulties in PG identification, especially IPG.\u003c/p\u003e \u003cp\u003eThe Chinese guideline had reported the correlations between the PG and thyroid gland[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], but it was not helpful in rapid IPG searching during surgery, especially when IPG was wrapped by the thymus. Also, the traditional way of searching for IPG was easily affected by various factors such as surgical experience, obesity, PG fatty degeneration and intraoperative bleeding[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e][\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. PG fluorescence technology can help to identify PG during surgery despite disadvantages like defective recognition effect, obesity limitation and time-consuming[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], making the technology difficult to popularize in primary hospitals. As far as we knew, the IPG and thymus were closely related to each other during the development of embryonic tissues[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Thus, we propose the hypothesis that RIPPT can improve IPG\u0026rsquo;s identification and orthotopic retention rates.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients Characteristics\u003c/h2\u003e \u003cp\u003eA total of 236 continuous patients were enrolled from August 2019 to December 2020 in this prospective single-arm study. The inclusion criteria were as below: All the patients were diagnosed as unilateral PTC by preoperative fine needle aspiration with the longest PTC diameter under 4cm. Patients with any of the following conditions will be excluded: tumor having invaded IPG and surrounded tissue; having a history of thyroid surgery or less than 16 years old or unavailable for the follow-up protocols; metastatic lymph nodes found in the preoperative examination. General characteristics, intraoperative factors, pathological examination, the number of total LNs and metastatic LNs in the resected specimens, and postoperative complications were collected retrospectively. The main observation was the rates of SPG and IPG recognition, orthotopic retention, auto-transplantation, serum calcium level, and PTH levels in both hands. All the patients had the operation of thyroid lobectomy plus dissection of the central lymph node, which was performed by the same surgeon.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eIPG types\u003c/h2\u003e \u003cp\u003eAccording to the relationship between the IPG and thymus and its location, IPG was classified into five types (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Type A: within the thymus (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA); Type B: at the top of the thymus (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB); Type C: extremely near the top of the thymus, where the distance was equal to or less than 5mm (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC); Type D: near the top of the thymus, but the distance was more than 5mm (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD); Type E: anatomically irrelevant with thymus or IPG was attached to the thyroid (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eE).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eSurgical procedure of IPG identification by RIPPT\u003c/h2\u003e \u003cp\u003eInitially, the lateral side of the thyroid gland was separated to expose the common carotid sheath from the upper pole of the thyroid to the thymus. The thyroid gland was then pulled to the contralateral side for the convenience of IPG observation. Next, we pulled the thyroid gland and observed the IPG in the lower part of the thyroid gland (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). If the IPG was attached closely to the thyroid or difficult to be retained in situ, then timely auto-transplantation was mandatory.\u003c/p\u003e \u003cp\u003eEmploying the previous method[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], we later exposed the RLN quickly and found the thymus which would be separated to its top from the caudal to the cephalic direction (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). During this process, we might find the IPG within the thymus or at the top of the thymus (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Simultaneously, IPG and thymus could be in situ reserved as a whole (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). However, IPG was wrapped by the thymus in some patients, making it difficult to be identified (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). In this case, we continued to separate the thyroid thymus ligament along the thyroid. Generally, IPG can be found within 10 mm from the top of thymus. If IPG was 10 mm further from the top of thymus or IPG was found with no blood supply, IPG auto-transplantation into the brachioradialis muscle of the left forearm was needed promptly because existing studies had shown that PG auto-transplantation could preserve its function[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In all the patients, the suspected parathyroid tissue was punctured 3\u0026ndash;5 times with a 1ml needle (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e), and then the needle was thoroughly rinsed in 1ml saline. Finally, the PTH rapid test paper combined with the dropping of 100ul of eluent was applied to detect whether the suspected tissue was parathyroid. The testing result was observed 5 mins later, with a certain color for positive and no color for negative (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eSubsequently, we continued to perform thyroidectomy and central lymph node dissection according to China\u0026rsquo;s thyroid guidelines[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e][\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. If the IPG was not found during the procedure mentioned above, searching for IPG in the excised specimen was indispensable.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eFollow-up and postoperative treatment of hypoparathyroidism\u003c/h2\u003e \u003cp\u003eAll patients were accompanied by 12\u0026ndash;20 months of following up. The PTH level and serum calcium level were tested in 1 day, 2 months, and 6 months after surgery. When PTH level was under 1.3mmol/L six months after surgery, postoperative hypoparathyroidism was confirmed. Levothyroxine treatment was necessary for all patients after surgery. Calcium supplementation and vitamin D were prescribed before the PTH level of patients with symptomatic hypoparathyroidism reaching normal. Intravenous substitution therapy of calcium was adopted in the case of serious symptomatic hypocalcemia.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed by SPSS 26.0, Chicago, IL, USA. All data was presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. Comparisons between the two groups were conducted by independent sample T-test or Chi-Square test, requiring P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was statistically significant. P values are represented as P\u0026thinsp;\u0026lt;\u0026thinsp;0.05, no significance and P\u0026thinsp;\u0026ge;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e \u003cb\u003ePatient characteristics: IPG anatomical types, SPG and IPG recognition, orthotopic retention, auto-transplantation.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe overall proportion of patients showing a positive anatomical association between the IPG and thymus was 79.65% (184/231), and the specific distributions of IPG anatomic type were as follows: Type A, 11.69% (27/231); Type B, 11.69% (27/231); Type C, 23.38% (54/231); Type D, 32.9% (76/231); and Type E, 20.35% (47/231). Their corresponding IPG orthotopic retention rate were 100% (27/27), 92.59% (25/27), 20.37% (11/54), 0% (0/76), and 0% (0/47) respectively. Among the patients with IPG Type E, 35/47 patients had an IPG closely attached to the thyroid surface, and only 12/47 patients required a careful search of the IPG in the resected specimens.\u003c/p\u003e \u003cp\u003eThe SPG identification and auto-transplantation rate was 100% (236/236) and 8.47% (20/236), while IPG identification and auto-transplantation rate was 97.88% (231/236) and 74.46% (172/231), respectively. The rate of one or two PG auto-transplantation was 67.80% (160/236) and 6.8% (16/236). The overall PG survival rate was 86.36% (152/176). However, PG survival rate significantly differed by the number of PG being auto-transplanted, as one PG is 85% and two is 100%. We also found the patients\u0026rsquo; right-hand and the left-hand PTH level from two PG auto-transplantation group were both higher than those from one PG auto-transplantation group in 2 months and 6 months after surgery. (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePTH level and survival rate of PG in the patients with different numbers of PG auto-transplantation\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTime points of postoperative review\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOne IPG auto-transplantation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTwo IPG auto-transplantation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eRight-hand PTH level\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epre-operation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.95\u0026thinsp;\u0026plusmn;\u0026thinsp;1.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.092\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 days after surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.349\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 months after surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.026\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 months after surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.59\u0026thinsp;\u0026plusmn;\u0026thinsp;1.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.587\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft-hand PTH level\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 months after surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.46\u0026thinsp;\u0026plusmn;\u0026thinsp;12.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35.46\u0026thinsp;\u0026plusmn;\u0026thinsp;20.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.045\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurvival rate of PG auto-transplantation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 months after surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e122/176\u003c/p\u003e \u003cp\u003e(86.36%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16/16\u003c/p\u003e \u003cp\u003e(100%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.007\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eThe risk factors in the patients with IPG unidentified during the operation\u003c/h2\u003e \u003cp\u003eWe found IPG in most patients during operation, but some IPG (5/236) were still missing. Meanwhile, our postoperative paraffin pathology results revealed that there were 15 patients with accidental removal of IPG, except the previous five cases. We suspect the IPG found in postoperative paraffin specimens may be the fifth PG. Further analysis also showed the IPG unidentified was mainly related to the age(P\u0026thinsp;=\u0026thinsp;0.013), but not associated with IPG anatomical type, body mass index, tumor size, total numbers of lymph nodes, numbers of lymph node metastases, diabetes, hypertension, or thyroid disease. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe risk factors in the patients with IPG unidentified during the operation\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIPG identified\u003c/p\u003e \u003cp\u003e231 cases\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIPG unidentified\u003c/p\u003e \u003cp\u003e5 cases\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChi-square or T value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45.06\u0026thinsp;\u0026plusmn;\u0026thinsp;11.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e57.06\u0026thinsp;\u0026plusmn;\u0026thinsp;9.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-2.496\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.013\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor side\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e106/125\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.381\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody mass index (Kg/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.59\u0026thinsp;\u0026plusmn;\u0026thinsp;5.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.165\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.877\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYears(\u0026le;\u0026thinsp;55y/\u0026gt;55y)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e189/42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3/2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.234\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex (Male/Female)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58/173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal numbers of lymph nodes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.42\u0026thinsp;\u0026plusmn;\u0026thinsp;8.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.223\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.824\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumbers of lymph node metastases\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.09\u0026thinsp;\u0026plusmn;\u0026thinsp;1.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.544\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.587\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18/231\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1/5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.345\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30/231\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2/5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.137\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThyroid disease\u003c/p\u003e \u003cp\u003e(Hashimoto or nodular goiter)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e194/231\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3/5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.192\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eComparison of serum PTH and calcium level between patients with different characteristics\u003c/h2\u003e \u003cp\u003eWe found that PTH level of patients with IPG orthotopic retention was higher than that of patients with IPG auto-transplantation; however, this difference was only found at 1 day and 6 months after surgery. Nevertheless, there was no statistical difference in serum calcium levels between the two groups after surgery. (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe PTH and serum calcium level between the patients with IPG orthotopic retention and auto-transplantation after surgery.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIPG orthotopic retention\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eIPG auto-\u003c/p\u003e \u003cp\u003etransplantation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eChi-square value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (pre-operation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e3.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.074\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.941\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (1 days after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e3.36\u0026thinsp;\u0026plusmn;\u0026thinsp;1.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.424\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.016\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (2 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e3,82\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.041\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.968\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (6 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e4.18\u0026thinsp;\u0026plusmn;\u0026thinsp;1.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.767\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (pre-operation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e2.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.185\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.853\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (1 days after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e2.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.268\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.206\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (2 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e2,39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.448\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.654\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (6 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e2.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.678\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.098\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe further analyzed the PTH level and serum calcium level in 3 types of IPG orthotopic retention and found them with no statistical difference in the single factor analysis of variance in three-time nodes after surgery. Neither was there any difference in PTH and serum calcium level in further comparisons between any two groups. (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe PTH and serum calcium level among the patients with different IPG type of orthotopic retention\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eIPG type of orthotopic retention\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eF value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eType A\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eType B\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eType C\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (pre-operation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.64\u0026thinsp;\u0026plusmn;\u0026thinsp;1.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.88\u0026thinsp;\u0026plusmn;\u0026thinsp;0.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.577\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.204\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (1 days after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.35\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.44\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.30\u0026thinsp;\u0026plusmn;\u0026thinsp;0.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.138\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.937\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (2 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.68\u0026thinsp;\u0026plusmn;\u0026thinsp;1.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.074\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.974\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (6 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.24\u0026thinsp;\u0026plusmn;\u0026thinsp;1.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.203\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.894\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (pre-operation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.339\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.270\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (1 days after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.20\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.136\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.342\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (2 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.306\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.821\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (6 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.641\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.591\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe also found that the PTH level in patients with SPG and IPG orthotopic retention was significantly higher than that in patients with SPG and IPG auto-transplantation at the three-time node after surgery. However, there was no statistical difference in the serum calcium level between them at the three-time node after surgery. (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ethe differences of the PTH and serum calcium level between the patients with SPG and IPG orthotopic retention or not (SPG and IPG auto-transplantation)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003evariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSPG and IPG orthotopic retention\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSPG and IPG auto-transplantation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChi-square value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (pre-operation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.02\u0026thinsp;\u0026plusmn;\u0026thinsp;1.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-0.546\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.592\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (1 days after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.44\u0026thinsp;\u0026plusmn;\u0026thinsp;1.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.422\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.018\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (2 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.388\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTH (6 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.23\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.37\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.203\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.031\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (pre-operation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.871\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.397\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (1 days after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.943\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.349\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (2 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.121\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.266\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa (6 months after surgery)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.712\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.053\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSide effects and operative complications\u003c/h2\u003e \u003cp\u003eSome patients encountered complications including postoperative bleeding (1/236), transient hypoparathyroidism (3/236) and transient recurrent laryngeal nerve palsy (6/236). Patients with transient hypoparathyroidism showed no low-calcium symptoms and PTH level reached normal after two weeks. Also, patients with transient vocal cord dyskinesia recovered after 2 months according to electronic laryngoscope.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, a new strategy was used to search IPG by RIPPT and results showed IPG identification and auto-transplantation rate was 97.88% and 74.46% respectively. Meanwhile, the proportion of identified and transplanted IPG was higher than that recorded in previous literature[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e][\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e][\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The proportion of patients with anatomical relationship between IPG and thymus was 77.97% (184/236), and the survival rate of one PG and two PG auto-transplantation was 85% and 100% respectively. The result mentioned above indicated that there was an anatomical relationship between IPG and thymus for most patients, even with 5/236 IPG unidentified and 15/236 IPG accidental removal. The theoretical basis lies in the embryonic development relationship between IPG and thymus, as well as the simplicity and feasibility of thymus identification during surgery by RIPPT.\u003c/p\u003e \u003cp\u003eRIPPT did help to find the IPG quickly, but it was uncertain whether IPG orthotopic retention was beneficial to its functional protection. In this study, we found PTH level of patients with IPG orthotopic retention was significantly higher than that of patients with IPG auto-transplantation at 1 day and 6 months after surgery. However, we did not observe differences in the PTH and serum calcium levels among the 3 IPG anatomical types with orthotopic retention, and this result might be due to our clinical decision of IPG auto-transplantation. We choose IPG orthotopic retention when we were confident with its blood supply. Otherwise, we would choose IPG auto-transplantation. Meanwhile, the question that whether auto-transplantation or orthotopic retention should be chosen to protect IPG well when IPG has been found could be explained by our data revealing elevated PTH level of patients with SPG and IPG orthotopic retention versus the one with both auto-transplantation.\u003c/p\u003e \u003cp\u003eMore importantly, RIPPT not only increases the efficiency of IPG protection but also reduces the difficulty of thyroid surgical operation. During surgery, we separated the external side of the thyroid gland before searching for the thymus, dealing with the middle and lower thyroid veins on the superficial surface of the common arterial sheath, so as not to cause bleeding which could affect surgical field; Then, we found and protected RLN quickly, avoiding damage in the process of IPG searching according to our previous method; Moreover, we advocated the priority of IPG protection and IPG orthotopic retention, but auto-transplantation should be carried out timely when IPG could not be preserved in situ; Finally, complete the surgery with the help of RIPPT could reduce the difficulty of LNs dissection and avoid RLN injury and PG midsection, on the premise that RLN and IPG had been protected. So RIPPT is simple and safe, especially suitable for surgeons lacking surgical experience. This study was only applicable to \"thyroid cancer patients who receive unilateral/bilateral surgery\", and the technique can be performed on the central neck dissection (CND) side. Additionally, as the indications for CND in the guidelines are gradually restricted, the indications of RIPPT will also be more limited.\u003c/p\u003e \u003cp\u003eWang JB reported the way of detecting blood supply to the IPG based on the \"layer of thymus-blood vessel-inferior parathyroid gland\" concept[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], and Wang X also used a novel meticulous thyrothymic ligament dissection technique to explore the inferior parathyroid gland. But their approach was more difficult to preserve the branches of the inferior thyroid artery, not advised to be popularized and recommended in the primary hospital[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Different from their surgical techniques, our study focused on searching IPG by RIPPT and decide whether IPG should be retained in situ according to IPG type. Since IPG in situ with blood supply from the thymus are more likely to survive, we chose the more aggressive auto-transplantation for patients with type D IPG and shortened the time of IPG searching to avoid its function impairment[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough this technology was widely used in our hospital, it still remained some shortcomings that required to be improved as follows: 1. Further validation was needed for the blood supply or later microcirculation establishment in the IPG orthotopic retention; 2. The PTH level in this study was affected by the IPG auto-transplantation and contralateral PG compensation; 3. More IPG auto-transplantation was selected in the patients with type D IPG, so there was no comparison in the PTH level between the type C and D IPG, an active strategy of IPG situ retention with type D was needed for further validation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe RIPPT technique emphasizes the primary concept of IPG protection during thyroid surgery. It is beneficial for rapid IPG searching and functional protection based on short-term data. Therefore, it might be a method worth popularizing to hospitals for protecting PG function.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003ePTC papillary thyroid carcinoma\u003c/p\u003e\u003cp\u003eRLN recurrent laryngeal nerve\u003c/p\u003e\u003cp\u003ePG parathyroid gland\u003c/p\u003e\u003cp\u003eSPG superior parathyroid gland\u003c/p\u003e\u003cp\u003eIPG Inferior parathyroid gland\u003c/p\u003e\u003cp\u003ePTH parathyroid hormone\u003c/p\u003e\u003cp\u003eTC thyroid carcinoma\u003c/p\u003e\u003cp\u003eIONM intraoperative neuromonitoring\u003c/p\u003e\u003cp\u003eTRIPG thymus-related inferior parathyroid gland\u003c/p\u003e\u003cp\u003eRIPPT retrograde inferior parathyroid protection technique\u003c/p\u003e\u003cp\u003eLNs Lymph nodes\u003c/p\u003e"},{"header":"Declarations","content":" \u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003e The study was approved by the ethics committee of Fujian Medical University Union Hospital. (2019KY122)\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompeting interests\u003c/strong\u003e \u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis study was supported by Joint Funds for the Innovation of Science and Technology, Fujian province (grant number: 2019KY122) and Clinical Research Center for Precision Management of Thyroid Cancer of Fujian Province (grant number: 2022Y2006)\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eNo editorial services were used for this manuscript. Wenxin Zhao contributed to the concept of study design and final approval of the work. Shouyi Yan contributed by writing and data analysis. Yuhan Chen contributed through the collection and analysisof data, preservation of original data, and preparation of the manuscript. Liyong Zhang contributed by review of data and analysis of data. Shaojun Cai contributed through data acquisition. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eAll contributors of this manuscript are named co-authors. Shouyi Yan and Yuhan Chen are named co-first authors. Wenxin Zhao is named corresponding author. No other acknowledgments are applicable.\u003c/p\u003e\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e \u003cp\u003eThe datasets generated and/or analyzed during the current study are not publicly available due to the complexity and amount of data, which requires special processing software. However, data are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSiegel RL, Miller KD, Goding Sauer A, Fedewa SA, Butterly LF, Anderson JC, Cercek A, Smith RA, Jemal A. Colorectal cancer statistics, 2020. Cancer J Clin. 2020;70(3):145\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCabanillas ME, McFadden DG, Durante C. Thyroid cancer. Lancet. 2016;388(10061):2783\u0026ndash;95.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCirocchi R, Arezzo A, D\u0026rsquo;Andrea V, Abraha I, Popivanov GI, Avenia N, Gerardi C, Henry BM, Randolph J, Barczy\u0026ntilde;ski M. Intraoperative neuromonitoring versus visual nerve identification for prevention of recurrent laryngeal nerve injury in adults undergoing thyroid surgery. 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Int J Endocrinol. 2022;2022(1):6556252.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang X, Si Y, Cai J, Lu H, Tong H, Zhang H, Wen J, Shen M. Proactive exploration of inferior parathyroid gland using a novel meticulous thyrothymic ligament dissection technique. Eur J Surg Oncol. 2022;48(6):1258\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHicks G, George R, Sywak M. Short and long-term impact of parathyroid autotransplantation on parathyroid function after total thyroidectomy. Gland Surg. 2017;6(Suppl 1):75.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-endocrine-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bend","sideBox":"Learn more about [BMC Endocrine Disorders](http://bmcendocrdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bend/default.aspx","title":"BMC Endocrine Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Inferior parathyroid gland, Papillary thyroid cancer, Thymus-related inferior parathyroid gland, Thyroid surgery, Retrograde inferior parathyroid protection technique, Thymus preservation","lastPublishedDoi":"10.21203/rs.3.rs-4935264/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4935264/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThe importance of parathyroid gland protection has been widely recognized in thyroid surgery. However, it remains difficult to quickly identify parathyroid gland, especially the inferior parathyroid gland (IPG). This study aimed to evaluate the effectiveness of retrograde inferior parathyroid protection technique (RIPPT) based on thymus preservation.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA total of 236 patients was enrolled in this study from August 2019 to December 2020. We used RIPPT to identify and protect inferior parathyroid gland (IPG), followed by analyzing its identification rate and anatomical types of IPG. Thereafter, we compared the parathyroid hormone (PTH) and serum calcium level of IPG orthotopic retention patients with that of IPG auto-transplantation patients among different IPG anatomical types.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eIn all cases, the rate of IPG identification and auto-transplantation was 97.88% (231/236) and 74.46% (172/231) respectively. The proportion of patients with an anatomical relationship between the IPG and thymus was 77.97% (184/236). Furthermore, we found that PTH level in patients with IPG orthotopic retention was higher than that in those with IPG auto-transplantation in 1 day or 6 months after surgery; PTH level was also found higher in patients with superior parathyroid gland (SPG) and IPG orthotopic retention than the ones receiving both auto-transplantation.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003eRetrograde inferior parathyroid protection technique (RIPPT) argues for the primacy of the protection concept of inferior parathyroid gland (IPG) in thyroid surgery, and is proven to be effective in the rapid identification and functional protection of IPG based on short-term data.\u003c/p\u003e","manuscriptTitle":"Clinical significance of retrograde inferior parathyroid protection technique based on thymus preservation in thyroid surgery","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-10-16 06:09:55","doi":"10.21203/rs.3.rs-4935264/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-27T06:27:20+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-08-22T22:09:40+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-08-22T22:09:32+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Endocrine Disorders","date":"2024-08-19T02:04:07+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-endocrine-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bend","sideBox":"Learn more about [BMC Endocrine Disorders](http://bmcendocrdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bend/default.aspx","title":"BMC Endocrine Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5b531559-2823-4075-8112-155c8ea45989","owner":[],"postedDate":"October 16th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-01-27T16:05:29+00:00","versionOfRecord":{"articleIdentity":"rs-4935264","link":"https://doi.org/10.1186/s12902-025-01838-y","journal":{"identity":"bmc-endocrine-disorders","isVorOnly":false,"title":"BMC Endocrine Disorders"},"publishedOn":"2025-01-26 15:58:26","publishedOnDateReadable":"January 26th, 2025"},"versionCreatedAt":"2024-10-16 06:09:55","video":"","vorDoi":"10.1186/s12902-025-01838-y","vorDoiUrl":"https://doi.org/10.1186/s12902-025-01838-y","workflowStages":[]},"version":"v1","identity":"rs-4935264","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4935264","identity":"rs-4935264","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}