The impact of raised body mass index on parathyroid surgery: a single centre experience

The impact of raised body mass index on parathyroid surgery: a single centre experience | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 13 September 2025 V1 Latest version Share on The impact of raised body mass index on parathyroid surgery: a single centre experience Authors : Nicholas O’Keeffe A 0000-0001-9700-3969 [email protected] , Freya Timon , Nial McInerney , Andreea Nae , and Conrad Timon Authors Info & Affiliations https://doi.org/10.22541/au.175775595.54283631/v1 190 views 87 downloads Contents Abstract References Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Background The prevalence of obesity continues to rise and presents increasing challenges in surgical care. Elevated body mass index (BMI) may affect perioperative management and outcomes. This study evaluates the impact of obesity on operative metrics in parathyroid surgery. Methods A retrospective review of 225 consecutive parathyroid surgeries performed by a single surgeon between September 2019 and September 2023 was conducted. Patient demographics, BMI, surgical time, preoperative imaging, and biochemical parameters were analyzed. Patients were categorized as normal weight, overweight, or obese according to WHO BMI classifications. Results Among 225 patients, 89 (39.6%) were of normal weight, 81 (36.0%) were overweight, and 55 (24.4%) were obese. Obese patients had significantly longer surgical times than normal-weight patients (p < 0.001). Four-gland exploration was also associated with longer surgical times as was bilateral neck exploration (P<0.05). Obese patients exhibited higher preoperative parathyroid hormone (PTH) levels (p < 0.01). Conclusion Obesity was independently associated with prolonged surgical times and elevated preoperative PTH levels in patients undergoing parathyroidectomy, though complication rates were comparable across BMI categories. Title: The impact of raised body mass index on parathyroid surgery: a single centre experience Background The prevalence of obesity continues to rise and presents increasing challenges in surgical care. Elevated body mass index (BMI) may affect perioperative management and outcomes. This study evaluates the impact of obesity on operative metrics in parathyroid surgery. Methods A retrospective review of 225 consecutive parathyroid surgeries performed by a single surgeon between September 2019 and September 2023 was conducted. Patient demographics, BMI, surgical time, preoperative imaging, and biochemical parameters were analyzed. Patients were categorized as normal weight, overweight, or obese according to WHO BMI classifications. Results Among 225 patients, 89 (39.6%) were of normal weight, 81 (36.0%) were overweight, and 55 (24.4%) were obese. Obese patients had significantly longer surgical times than normal-weight patients (p < 0.001). Four-gland exploration was also associated with longer surgical times as was bilateral neck exploration (P<0.05). Obese patients exhibited higher preoperative parathyroid hormone (PTH) levels (p < 0.01). Conclusion Obesity was independently associated with prolonged surgical times and elevated preoperative PTH levels in patients undergoing parathyroidectomy, though complication rates were comparable across BMI categories. Key Points Significant findings of the study The study underscores the increasing prevalence of obesity and its potential to complicate parathyroid surgical management. Operative time is significantly prolonged in obese patients: Elevated BMI was associated with an increase in operative duration, suggesting technical challenges or anatomical considerations. What the study adds Clarifies the surgical impact of obesity in parathyroid disease The first study to demonstrates that elevated BMI is associated with longer surgical duration in parathyroid surgery Key Words: Body Mass Index, Morbidity, Obesity, Parathyroid Hormone, Primary Hyperparathyroidism Introduction Obesity is a growing health concern, driven by lifestyle, environmental and behavioral factors such as poor diet and physical inactivity. In the United States, it ranks as the second leading cause of preventable death after smoking. 1, 2 According to The World Health Organization (WHO), overweight is defined as a body mass index (BMI) greater than 25 (kg/m 2 ) and obesity as a BMI greater than 30 kg/m 2 . The WHO estimates that there are over 1.9 billion adults who are overweight globally with 650 million classified as obese . 3, 4 Surgeons often consider obesity a complicating factor due to its association with increased perioperative risk and worse perioperative outcomes. 5 Multiple studies have demonstrated higher morbidity and mortality following major procedures, particularly abdominal surgeries, in obese patients. 6, 7 Limited data exists regarding the influence of elevated BMI on thyroid and parathyroid surgeries. A study by Canu et al. (2020) found no difference in postoperative complications or hospital stay among obese patients undergoing thyroidectomy. 8 The aim of this review of 225 consecutive patients with primary hyperparathyroidism (pHPT), was to evaluate the impact of BMI on parathyroid surgery particularly focusing on factors influencing surgical time in parathyroid surgery. Methods Patient population A retrospectively reviewed 225 patients who underwent parathyroid surgery at a tertiary referral centre between September 2019 and September 2023. Patient’s data were extracted from a prospectively maintained surgical database of a single surgeon (senior author). Clinical data was obtained through detailed chart and operative record review. Data including demographic information, BMI, type of surgery performed, preoperative imaging, serum calcium and parathyroid hormone (PTH) levels, and total surgical times were collected. Surgical method The senior author routinely obtained at least two imaging modalities prior to surgery, usually Ultrasound (US), SPECT-CT or Technetium (99mTc) Sestamibi scan in most cases for gland localization. A facial nerve monitor is used in all cases. Patients are generally positioned with a shoulder roll and head ring. To improve exposure in obese patients, we consider partial strap muscle division in select cases to enhance operative field. Biochemical markers including PTH and calcium are generally performed in the recovery room followed by repeat blood samples taken the following morning. At present the senior author does not use intraoperative PTH sampling or other surgical adjuncts to identify parathyroid glands. Definitions Patients were stratified into three BMI groups according to WHO criteria; Normal weight: BMI 18.5-24.9 kg/m 2 ; Overweight: BMI 25.0 – 29.9 kg/m 2 ; Obese: BMI > 30.0 kg/m 2 . Underweight patients (BMI <18.5) were included in the normal-weight group, as there was no statistically significant difference in outcomes between these subgroups. Inclusion and exclusion criteria Patients were included if they underwent primary parathyroidectomy for PHPT and had complete demographic, imaging, and operative records. Exclusion criteria included re-operative surgery, parathyroid carcinoma, or concurrent thyroidectomy. Statistical analysis Continuous variables were compared using one-way ANOVA, and categorical data with chi-squared tests. Multivariate linear regression was used to identify independent predictors of surgical time. A p -value < 0.05 was considered statistically significant. Results During the study period, 225 patients underwent parathyroidectomy for primary hyperparathyroidism (pHPT). Patients had height and weight information collected at the time of study and were included for analysis in this study. The mean age of the patients was 58 +/- 1 years and 81.3 % were female. The mean BMI was 28.2 kg/m 2 +/- 0.92 kg/m 2 . Of the 225 patients, 89 (39.6%) were classified as normal weight, 81 (36.0%) as overweight, and 55 (24.4%) as obese. Underweight patients were included in the normal weight group due to no statistically significant differences in measured outcomes. Table 1 presents preoperative characteristics of patients undergoing parathyroid surgery, stratified by BMI category (Normal, Overweight, Obese). Variables analyzed include age, sex, serum calcium, serum parathyroid hormone (PTH) and successful preoperative localization on imaging. Obese patients had a significantly higher preoperative parathyroid hormone as compared to normal and overweight patients ( p <0.05). No statistically significant differences were observed between the BMI groups in terms of age, serum calcium, sex or localization on imaging. Mean operative time was 35.8 minutes for normal weight patients (range: 20–65 mins), 35.5 minutes for overweight patients (range: 14–120 mins), and 50.9 minutes for obese patients (range: 18–120 mins). Obese patients had significantly longer operative times compared to both normal and overweight groups ( p < 0.001). The types of surgery performed included single gland excision (181, 80 %), 2 gland excision (8, 3.6 %), 3 gland excision (1, 0.4 %) and 1 hemithyroidectomy for an intrathyroidal adenoma (1, 0.4 %) Table 2. 42 (18 %) of patients underwent bilateral neck exploration which was an independent predictor of increased surgical time in multivariate analysis (P<0.05), reflecting more extensive surgical dissection. Most cases of bilateral neck exploration concerned cases where imaging failed to locate an adenoma preoperatively. Table 3 presents a univariate and multivariate linear regression analyses to assess factors associated with prolonged surgical time. In multivariate analysis after adjusting for age, sex, weight category, operation type and imaging localization, obesity was identified as an independent predictor of increased surgical time compared to normal weight (β = +13.55 minutes, p < 0.001). Four-gland exploration was also significantly associated with longer surgical times ( p < 0.001), while age, sex, and imaging localization were not statistically significant. Postoperative complications were uncommon and included transient hoarseness (3), transient hypocalcemia (6), wound infection (4), seroma formation (2) and 1 lower respiratory tract infection. There was no statistically significant difference in complication rates among normal weight, overweight, and obese patients ( p = 0.727). With a minimum of 6 month follow up after parathyroidectomy, eucalcemia or cure was achieved in 100 % of normal weight patients, 98.8 % of overweigh patients and 98.2 % 0f obese patients ( p = 0.485). Discussion Parathyroidectomy is the definitive treatment for primary hyperparathyroidism (pHPT), most commonly involving removal of a single hyperfunctioning gland. Approximately 10% of cases involve multiple adenomas or four gland hyperplasia. 9, 10 In 2017, an estimated 17,000 parathyroidectomies were performed in the United States . 11 Although the mortality associated with parathyroid surgery is low, notable complications include cervical haematoma, recurrent laryngeal nerve injury and persistent or recurrent disease. 9 Surgeon experience plays a critical role in minimizing these risks. Stavrakis et al. (2007) demonstrated that surgeons performing over 100 endocrine procedures annually had significantly lower complication rates. 12 Obesity is traditionally perceived as a complicating factor in surgery due to associations with increased morbidity, technical difficulty and perioperative management challenges. While this association is well documented in abdominal surgery. 6,7 The evidence is less clear for thyroid and parathyroid surgery. Certain studies suggest that obesity may not significantly increase complication rates for endocrine surgery. 8 In this study, obese patients exhibited higher preoperative parathyroid hormone (PTH) levels compared to individuals with normal weight which is consistent with published literature. 14, 15 The increased PTH may reflect delayed diagnoses in obese patients due to overlapping symptoms with metabolic syndrome or altered vitamin D metabolism. Pitt et al in their analysis of 776 patients identified a significantly higher preoperative PTH in obese patients as compared to non-obese as well larger glands and longer hospital stays without increased complication rates. 15 The longer surgical time in our study is likely multifactorial including reduced neck extension due to body habitus which may hinder surgical access, increase difficulty and prolong dissection. 8,15 While surgical times was significantly increased, complication rates remained consistent across BMI groups, underscoring the longer surgeries do not necessarily translate to poorer outcomes. These results align with a growing body of literature suggesting that, although obesity may influence certain surgical metrics (e.g. surgical times) it does not appear to affect safety or efficacy in parathyroidectomy. 15, 16 Limitations of this study include its retrospective nature, single-surgeon design, and relatively small sample size which may limit generalizability. Operative extent was inferred from pathology and broad classification of unilateral versus bilateral neck exploration as opposed to documented dissection field. Confounding variables such as previous neck surgery, gland weight, and specific anatomical challenges were not analyzed in this cohort. Conclusion While obesity is a significant public health issue, its impact on the safety and outcome of parathyroid surgery appears limited. Obesity was associated with higher preoperative PTH and longer operative time. This may reflect increased soft tissue dissection and localization difficulty. However, there is no significant increase in complications observed. These findings support the safe and effective management of obese patients undergoing parathyroidectomy in high-volume centers in experienced surgeons. Acknowledgements None. Ethics Statement Ethical approval was obtained from the regional research committee. Data Availability Statement Data are available upon request. Tables Table 1: Baseline Demographics and Preoperative Characteristics by BMI Category Age (mean, range) [years] 59.82 (23.0–93.0) 59.12 (21.0–83.0) 57.82 (20.0–78.0) 0.6702 Female (%) 82.0% 81.5% 80.0% 0.9544 Calcium (mean, range) [mmol/L] 2.73 (2.1–3.2) 2.78 (2.4–4.0) 2.74 (2.1–3.1) 0.3543 PTH (mean, range) [pg/mL] 96.25 (10.0–227.0) 118.28 (8.4–350.0) 125.41 (13.4–400.0) 0.0221 Localised on Imaging (%) 82.0% 74.1% 54.5% 0.0633 Table 2: Summary of operation type performed (glands excised/explored) 1 gland 181(80.4 %) 2 glands 8 (3.6 %) 3 glands 1 (0.4 %) 4 gland exploration 34 (15.1 %) Hemithyroidectomy (intrathyroidal adenoma) 1 (0.4 %) Table 3: Univariate and Multivariate regression of variables influencing surgical time Age –0.14 (–0.37 to 0.10) 0.250 –0.14 (–0.35 to 0.07) 0.180 Sex Female (Male) –0.54 (–8.17 to 7.08) 0.888 –0.03 (–6.83 to 6.77) 0.994 Weight Overweight (Normal) –0.38 (–6.87 to 6.11) 0.908 +1.53 (–4.63 to 7.69) 0.624 Obese (Normal) +16.21 (+9.62 to +22.80) <0.001 +13.55 (+7.19 to +19.91) <0.001 Operation type More than 1 gland (1 gland) +28.45 (+12.43 to +44.47) 0.001 +14.16 (–11.30 to +39.61) 0.273 4 glands (1 gland) +33.69 (+18.58 to +48.80) <0.001 +33.69 (+18.58 to +48.80) <0.001 Neck Exploration Bilateral (Unilateral) +3.96 (+0.39 to +7.54) 0.030 –8.70 (–15.96 to –1.44) 0.019 Imaging Localized (Not localized) +1.92 (–1.51 to +5.35) 0.268 +1.92 (–1.51 to +5.35) 0.268 References 1. 1. 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Authors Affiliations Nicholas O’Keeffe A 0000-0001-9700-3969 [email protected] Royal Victoria Eye and Ear Hospital View all articles by this author Freya Timon Royal Victoria Eye and Ear Hospital View all articles by this author Nial McInerney Royal Victoria Eye and Ear Hospital View all articles by this author Andreea Nae Royal Victoria Eye and Ear Hospital View all articles by this author Conrad Timon Royal Victoria Eye and Ear Hospital View all articles by this author Metrics & Citations Metrics Article Usage 190 views 87 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Nicholas O’Keeffe A, Freya Timon, Nial McInerney, et al. The impact of raised body mass index on parathyroid surgery: a single centre experience. Authorea . 13 September 2025. DOI: https://doi.org/10.22541/au.175775595.54283631/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. 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