Subcutaneous translocation of residual thyroid tissue: a novel functional-preserving technique for partial thyroidectomy with 1-year follow-up retrospective case series

Introduction

In recent years, the incidence of thyroid nodules and benign thyroid tumors has increased continuously (1). Surgical treatment is not generally required for benign thyroid tumors, however, for patients with clear surgical indications, it is necessary to preserve as much normal thyroid tissue as possible while completely resecting the lesion (2). Excessive resection of normal thyroid tissue may cause or aggravate postoperative hypothyroidism. Conversely, if only mass resection is performed and normal thyroid tissue is left in situ, the recurrence rate of residual glandular tumors is higher (3). If reoperation becomes necessary, local scarring can increase the risk of recurrent laryngeal nerve and parathyroid gland injury. Therefore, preserving normal thyroid tissue without increasing the risk of parathyroid gland and recurrent laryngeal nerve injury during reoperation has become an important clinical challenge. Traditional thyroid autotransplantation mainly adopts free gland tissue grafts, with either intramuscular or subcutaneous implantation. Existing techniques rely on fragmented, devascularized tissue transplantation, which is associated with uncertain long-term graft viability, slow functional recovery, persistent hypothyroidism risk, and unresolved concerns about in-stump tumor recurrence (4).

In this study, we propose the technique of translocating the remaining normal thyroid tissue into the subcutaneous space through the cleft at the sternocleidomastoid and sternohyoid muscle junction. This method enables maximal preservation of normal thyroid tissue, and may theoretically lower the risk of recurrent laryngeal nerve and parathyroid gland injury if reoperation is needed. To the best of our knowledge, this surgical approach has not been previously reported. We present this article in accordance with the STROBE reporting checklist (available at https://gs.amegroups.com/article/view/10.21037/gs-2026-0308/rc).

Methods

Study design and population

We performed a retrospective analysis of clinical data from 106 consecutively enrolled eligible patients who underwent residual thyroid gland transposition at The First Hospital of Qinhuangdao between May 2022 and May 2025, with no intentional case exclusion (Figure 1). All patients screened within this period who satisfied anatomical and clinical criteria received this translocation procedure; patients failing to meet inclusion standards underwent conventional thyroid resection instead. The cohort comprised 26 males and 80 females, aged 26–74 years, with a mean age of 52.3±12.2 years. This single-center retrospective cohort inevitably carries selection bias, as only patients meeting strict anatomical inclusion criteria were included. No formal sample size calculation was performed for this exploratory retrospective case series. The sample size consisted of all consecutive eligible patients treated from May 2022 to May 2025. Outcome estimates have limited precision, particularly for the small bilateral subgroup (n=12), whose findings are presented descriptively without broad generalization.

Figure 1 Patient flowchart of the retrospective study.

Inclusion criteria: (I) patients had surgical indications, such as local compression symptoms or progressive nodule growth, requiring surgical treatment; (II) normal thyroid function was documented before the operation; (III) preoperative fine-needle aspiration or intraoperative frozen‑section pathology suggested benign lesions; (IV) all patients underwent primary surgery; (V) the lower border of the normal gland in the upper thyroid extended above the cricoid cartilage level.

Exclusion criteria: (I) patients with hyperthyroidism or hypothyroidism; (II) Hashimoto’s thyroiditis or other thyroid disorders [routine assessment of anti-thyroperoxidase (TPO) and anti-Tg antibodies was applied to screen for autoimmune thyroid disease]; (III) preoperative fine-needle aspiration or intraoperative frozen‑section pathology could not exclude the possibility of malignancy; (IV) history of previous thyroid or neck surgery.

Ethical consideration

This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of The First Hospital of Qinhuangdao (No. 2022A007). Written informed consent was obtained from all patients. The patients and their families were informed of the advantages and disadvantages of retaining and transposing the residual glands before they agreed to the operation and signed the consent form.

Surgical technique

After successful general anesthesia, the neck was padded into a high‑extension position. A skin incision was made along the natural skin lines of the neck, and the cervical fascia was opened along the midline to expose the thyroid gland. The recurrent laryngeal nerve and parathyroid glands were protected using traditional fine capsular dissection. The upper pole vascular pedicle of the thyroid was carefully dissected to maintain intact arterial and venous outflow. The gland and tumor were mobilized from inferior to superior toward the upper pole vascular pedicle. Viable upper-pole normal thyroid tissue with intact blood supply was selected for translocation. Tumor enucleation was performed to preserve the remaining normal thyroid tissue in the upper pole (Figure 2A), creating a thyroid flap pedicled by the upper pole vascular pedicle. The residual tissue ranged from 2.0 to 3.5 cm in maximum diameter, with an estimated volume of 1.5–5.0 cm³. Adequate perfusion was confirmed by visual inspection for arterial pulsation, observation of capillary bleeding from the cut edge of the residual tissue, and Doppler ultrasound confirmation of blood flow in the pedicle. A hiatus of approximately 1.5–2.0 cm in diameter was created at the junction of the sternocleidomastoid and sternohyoid muscles to form an implantation pocket, through which the pedicled thyroid flap was passed. The flap was placed in the muscle space indentation at the sternocleidomastoid-sternohyoid junction, maintaining its normal anatomical orientation (Figure 2B). Intraoperative maneuvers aimed to prevent vascular pedicle torsion, extrinsic compression and venous congestion. The flap was fixed in the subcutaneous space with tension‑free sutures (Figure 2C). Translocation was unilateral when only one lobe contained eligible viable upper-pole tissue; bilateral translocation was undertaken if suitable tissue was available on both sides. A drain was placed, and the wound was closed in layers.

Figure 2 Intra‑operative photographs showing creation and placement of the vascularized pedicled thyroid flap. (A) Thyroid gland dissection with preservation of the upper pole vascular pedicle only. (B) Passage of the residual gland through the hiatus at the sternocleidomastoid-sternohyoid junction. (C) Fixation of the residual gland in the superficial subcutaneous muscle space.

Outcome assessment

Thyroid function tests were performed on admission and repeated at 1 month and 1 year postoperatively. Postoperative thyroid function [thyroid-stimulating hormone (TSH), free thyroxine (FT4)] at these two time points was defined as the primary outcome, while secondary outcomes included ultrasound-confirmed graft viability, graft atrophy, tumor recurrence, cervical cosmetic appearance, and postoperative surgical complications. Serum TSH and FT4 levels were recorded. TSH and FT4 were measured using the standard i4000 chemiluminescence method at our institution. The normal reference ranges were: TSH, 0.35–4.94 µIU/mL and FT4, 0.70–1.48 ng/dL. Standardized neck ultrasonography, conducted by radiologists within the same imaging department, was used to evaluate the location, size, echogenicity, internal blood flow, and morphology of transposed tissue at scheduled follow-up visits. Serial ultrasound images were compared longitudinally to assess temporal changes in graft characteristics. Graft viability was comprehensively judged based on preserved glandular morphology, maintained parenchymal echotexture, and detectable intralesional blood flow signal. All ultrasound reports were generated by attending radiologists blinded to thyroid function results; discrepancies in interpretation were resolved via consensus review. Postoperative hypothyroidism was defined as elevated TSH with decreased FT4 that required levothyroxine supplementation. Graft survival was defined as persistent viable translocated thyroid tissue with homogeneous echotexture and no atrophy on ultrasound. Graft atrophy was defined as a notable reduction in graft size with decreased parenchymal homogeneity. Tumor recurrence was defined as newly developed or enlarged nodules within residual or translocated thyroid tissue. Surgical complications including bleeding, surgical site infection, recurrent laryngeal nerve injury, and hypoparathyroidism were systematically documented during follow-up.

Statistical analysis

All statistical analyses were performed using SPSS software (version 21.0). Descriptive statistics were computed for clinical variables and TSH/FT4 parameters. Results are expressed as mean ± standard deviation. No formal sample‑size calculation was performed, as this was an exploratory case series; the sample size reflects all eligible patients treated with this technique during the study period (consecutive enrollment). All 106 patients completed both the 1‑month and 1‑year follow‑up visits; there was no loss to follow‑up.

Results

All 106 enrolled patients completed both 1-month and 1-year scheduled follow-up; no patients were lost to follow-up during the surveillance period. Among the 106 patients, 94 underwent unilateral thyroid surgery and 12 underwent bilateral surgery. In all bilateral cases, at least one normal gland was located in the upper pole. Baseline characteristics are summarized in Table 1.

All 106 patients were re-examined and followed up at our hospital. At the 1‑month postoperative review, mild localized swelling of the anterior neck was noted in some patients (Figure 3A), but there were no signs of inflammation (redness, swelling, heat, or pain). Thyroid ultrasonography confirmed that the residual thyroid tissue remained in the subcutaneous space and superficial muscle layer, and was viable without necrosis or pathological findings (Figure 3B). Thyroid function at 1 month is shown in Table 2.

Figure 3 Post‑operative clinical photographs and ultrasound images. (A) Mild localized swelling of the anterior neck at 1 month postoperatively. (B) Representative ultrasound image at 1 month showing the residual thyroid tissue located subcutaneously without pathological findings. (C) Normal neck appearance at 1‑year follow‑up, without local swelling. (D) Representative ultrasound image at 1 year showing the residual thyroid tissue located subcutaneously without pathological findings.

All 94 patients who underwent unilateral resection had normal thyroid function postoperatively and did not require thyroid hormone supplementation. Of the 12 patients who underwent bilateral resection, 5 developed hypothyroidism and were managed by the Department of Endocrinology, while the remaining 7 had normal thyroid function.

At the 6‑month follow‑up, neck appearance had returned to normal without local swelling (Figure 3C). Ultrasonography showed that the residual thyroid tissue remained in the subcutaneous space, maintained normal morphology, and had no pathological findings (Figure 3D). Thyroid function at 1 year is presented in Table 3, and overall clinical and imaging outcomes are summarized in Table 4.

The 5 patients with hypothyroidism were followed up by the Endocrinology Department, and the remaining 101 patients maintained normal thyroid function without hormone supplementation.

Discussion

Thyroid tumors are defined as one or more abnormal tissue masses within the thyroid gland that may arise from various causes. They are among the most common endocrine disorders. The prevalence of thyroid tumors detected by palpation ranges from 3% to 7%, while high-resolution ultrasound detects them in 19% to 68%of individuals. Although the majority of thyroid tumors are benign, approximately 7–15% are malignant (1,5). Many benign thyroid tumors can be managed with observation alone and do not require surgical intervention. Although controversial and less commonly used, radiofrequency ablation, microwave ablation, and anhydrous ethanol sclerotherapy may be considered for benign thyroid tumors that require intervention (6,7). Nevertheless, surgical resection remains the most conventional treatment.

The optimal extent of surgery for benign thyroid tumors that require operative management remains debated. Simple tumor enucleation or limited partial resection is not ideal because, if the tumor recurs and reoperation becomes necessary, scarring increases the risk of surgical complications. Injury to the recurrent laryngeal nerve and parathyroid glands is a primary concern. The reported incidence of transient and permanent recurrent laryngeal nerve injury during primary thyroid surgery is 1.4% and 0.2%, respectively (8). The incidence of accidental parathyroidectomy is 6.4% (9), while transient and permanent hypoparathyroidism occur in 25.9% and 2% of cases, respectively (8). When thyroid surgery must be repeated, the recurrent laryngeal nerve and parathyroid glands are at substantially higher risk because of local tissue adhesion and distorted anatomy. Indeed, the incidence of transient and permanent recurrent laryngeal nerve injury during reoperation rises to 4.6% and 0.7%, and transient and permanent hypoparathyroidism to 56.6% and 10%, respectively (9). These rates are significantly higher than those of primary surgery. Total lobectomy of the affected side is a safe and effective treatment for benign thyroid tumors and can reduce the risk of recurrence and the need for secondary surgery (10,11). However, more extensive thyroidectomy increases the risk of postoperative hypothyroidism and lifelong thyroid hormone replacement (12). Total thyroidectomy carries a significantly higher risk of postoperative hypothyroidism and long-term hormone dependence compared with subtotal thyroidectomy, underscoring the value of preserving functional thyroid tissue during surgery (13). Furthermore, the full physiological role of the thyroid gland is not completely understood, and the long‑term consequences of total thyroidectomy remain unclear. In contrast, the more normal thyroid tissue that is preserved, the lower the likelihood of needing thyroid hormone replacement, thereby reducing potential lifelong risks (14).

Our modified resection technique aims to preserves as much thyroid tissue as possible while protecting thyroid function, without increasing the risk of recurrent laryngeal nerve and parathyroid gland injury during reoperation. Animal studies have confirmed that thyroid autotransplantation is safe and does not adversely affect other tissues and organs (15). Human thyroid tissue transplanted into a prevascularized Cell Pouch™ device survived, maintained stable thyroglobulin production without adverse events, and shows promise for treating postoperative hypothyroidism (16). In our study, all patients underwent thorough preoperative evaluation, including fine-needle aspiration cytology or intraoperative frozen‑section pathology. If cytology or frozen section suggested possible malignancy, translocation was not performed. When a benign diagnosis was confirmed, the residual normal thyroid tissue was transposed to the subcutaneous space. The upper pole vascular pedicle, which contains both arteries and veins that nourish the residual thyroid tissue, was preserved to ensure graft survival and function (17). Functional recovery after free thyroid autotransplantation generally takes 6–9 months due to delayed graft revascularization (14). Our procedure preserves the upper-pole vascular pedicle, and most patients maintained stable thyroid function at the 1-month follow-up. However, this comparison should be interpreted cautiously, as inter-study differences in patient selection, tissue volume, implantation site and functional definitions may influence outcomes. Intraoperatively, the fascial hiatus at the sternocleidomastoid-sternohyoid junction was tailored to match the width of the vascular pedicle to avoid extrinsic compression. Adequate perfusion of the thyroid flap was confirmed visually by intact tissue color and brisk capillary bleeding after gentle incision of the gland capsule. The volume of retained tissue was determined by anatomical constraints and the extent of lesion resection. A key trade‑off exists between retaining enough tissue to preserve thyroid function and residual parenchyma-related recurrence risk. Larger residual tissue volumes facilitate functional preservation but carry a theoretically higher recurrence risk. Conversely, smaller tissue remnants may lower recurrence risk yet increase the probability of postoperative hypothyroidism (3,18). Our technique attempts to balance these competing priorities by harvesting only normal-appearing upper-pole tissue with reliable vascular supply and translocating it to a site convenient for long-term surveillance. In our cohort, retained tissue accounting for 15–30% of the original thyroid lobe volume was adequate to maintain euthyroidism in most patients, and the subcutaneous position enables early identification and intervention if recurrence develops.

Compared with mainstream treatments for benign thyroid nodules, subcutaneous thyroid remnant translocation offers unique merits. Lobectomy reduces recurrence but increases postoperative hypothyroidism risk, whereas in‑situ residual tissue raises complication risks in the event of reoperation. Radiofrequency ablation is only applicable for small nodules and cannot provide intact pathological specimens for large lesions (19). The tissue is easily accessible for clinical examination and ultrasound surveillance. Over long-term follow-up, any abnormalities—including recurrence or malignant transformation—can be readily detected and managed. Should resection of the translocated tissue become necessary, the procedure can theoretically be performed in the subcutaneous space without concern for recurrent laryngeal nerve and parathyroid gland injury. Our technique balances functional preservation and theoretical reoperative safety. Given the limited 1‑year follow‑up, longer‑term surveillance is required to confirm long‑term graft performance, recurrence risk and overall safety.

A key clinical consideration involves patients preoperatively diagnosed with benign thyroid lesions who are found to harbor incidental thyroid carcinoma on final histopathologic examination (20). Although this translocation technique was originally developed for benign thyroid disease, it allows timely and straightforward remedial management when unexpected malignancy is confirmed. The heterotopic thyroid graft located subcutaneously can be directly excised within the subcutaneous plane to perform completion thyroidectomy without deep dissection of the native thyroid bed, which theoretically prevents injury to the recurrent laryngeal nerve and parathyroid glands. Since the translocated thyroid tissue retains physiological iodine uptake function, complete resection of the graft eliminates functional thyroid parenchyma; failure to remove this tissue would interfere with postoperative radioactive iodine remnant ablation. Moreover, the superficial location of the graft facilitates repeated cervical ultrasonography during long-term oncologic surveillance.

Patients are often concerned about the cosmetic impact of subcutaneous transposition will affect this (21). However, the technique transposes only a small amount of residual normal tissue from the thyroid bed to the superficial muscle layer, without increasing overall tissue volume. Moreover, the tissue is placed in the natural anatomical depression between the sternocleidomastoid and sternohyoid muscle. In the short term, postoperative local swelling may cause a slightly raised appearance, but by 1‑year follow-up, the swelling had fully resolved, and neck appearance was normal in all patients.

Limitations

There are several limitations in this study. First, this was a retrospective, singlecenter, uncontrolled single-arm study lacking a control group receiving conventional partial thyroidectomy; without comparative data, the quantitative advantages of our technique cannot be statistically validated, and confounders cannot be balanced via randomization. Inherent selection bias further limits the generalizability of our findings. Second, the volume and weight of the translocated residual thyroid tissue were not quantitatively measured; therefore, we could not analyze the correlation between the amount of preserved tissue and postoperative thyroid function. Third, the follow-up duration was only 1 year. Although our data provide preliminary evidence of short-term graft viability and thyroid function, conclusions on long-term outcomes are restricted. We cannot reliably evaluate late tumor recurrence, progressive graft morphological changes, long-term complications, or risks related to potential future reoperation. Concerns about possible malignant transformation remain merely theoretical hypotheses and cannot be confirmed with the current dataset; extended surveillance is needed to clarify these issues. Fourth, we did not routinely measure anti‑TPO or anti‑Tg antibodies, which may have influenced thyroid function outcomes in patients with underlying autoimmune thyroid disease. Finally, the theoretical advantage of reducing reoperative complications could not be verified because no patient in this series required reoperation during the follow‑up period.

Conclusions

Subcutaneous translocation of residual normal thyroid tissue during partial thyroidectomy for benign tumors appears feasible and safe in this retrospective case series. It preserves thyroid function in most patients and maintains excellent cosmetic outcomes at 1‑year follow‑up. The potential benefit of reducing recurrent laryngeal nerve and parathyroid gland injury during reoperation remains theoretical and requires validation through longer-term follow-up and prospective comparative studies. This technique represents a promising surgical option for selected patients.

Acknowledgments

The authors would like to thank all patients who participated in this study.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-0308/rc

Data Sharing Statement: Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-0308/dss

Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-0308/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-2026-0308/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of The First Hospital of Qinhuangdao (No. 2022A007). Written informed consent was obtained from all patients.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Durante C, Hegedüs L, Czarniecka A, et al. 2023 European Thyroid Association Clinical Practice Guidelines for thyroid nodule management. Eur Thyroid J 2023;12:e230067. [Crossref] [PubMed]
2. Hao Q, Segel JE, Vanness DJ, et al. Hemithyroidectomy versus total thyroidectomy for patients with differentiated thyroid cancer: a systematic review and meta-analysis. Gland Surg 2025;14:2271-87. [Crossref] [PubMed]
3. Brady JS, Konuthula N, Lam A, et al. Risks Associated With Extent of Surgical Management for Benign, Non-Toxic Goiter. Laryngoscope Investig Otolaryngol 2025;10:e70214. [Crossref] [PubMed]
4. Sakr M, Mahmoud A. Review of Heterotopic Thyroid Autotransplantation. Clin Exp Otorhinolaryngol 2017;10:289-95. [Crossref] [PubMed]
5. Mu C, Ming X, Tian Y, et al. Mapping global epidemiology of thyroid nodules among general population: A systematic review and meta-analysis. Front Oncol 2022;12:1029926. [Crossref] [PubMed]
6. Sun J, Huang X, Zhang L, et al. Ultrasound-Guided Radiofrequency Ablation of Benign Thyroid Nodules: 2-Year Follow-Up Results from a Single Center. J Ultrasound Med 2026. [Epub ahead of print]. doi: 10.1002/jum.70346.
7. Xie G, Chen R, Liu F. Efficacy and safety of ultrasound-guided microwave ablation for benign thyroid nodules: A retrospective 12-month follow-up study. Journal of Radiation Research and Applied Sciences 2025;18:101980.
8. Medas F, Tuveri M, Canu GL, et al. Complications after reoperative thyroid surgery: retrospective evaluation of 152 consecutive cases. Updates Surg 2019;71:705-10. [Crossref] [PubMed]
9. Lin YS, Hsueh C, Wu HY, et al. Incidental parathyroidectomy during thyroidectomy increases the risk of postoperative hypocalcemia. Laryngoscope 2017;127:2194-200. [Crossref] [PubMed]
10. Papini E, Crescenzi A, D'Amore A, et al. Italian Guidelines for the Management of Non-Functioning Benign and Locally Symptomatic Thyroid Nodules. Endocr Metab Immune Disord Drug Targets 2023;23:876-85. [Crossref] [PubMed]
11. Ringel MD, Sosa JA, Baloch Z, et al. 2025 American Thyroid Association Management Guidelines for Adult Patients with Differentiated Thyroid Cancer. Thyroid 2025;35:841-985. [Crossref] [PubMed]
12. Takata K, Kojima T, Okanoue Y, et al. Risk factors and timing of postoperative hypothyroidism onset following hemithyroidectomy. Auris Nasus Larynx 2025;52:597-604. [Crossref] [PubMed]
13. Javidi S, Sadrizadeh S, Sadrizadeh A, et al. Postoperative complications and long-term outcomes after total and subtotal thyroidectomy: a retrospective study. Sci Rep 2025;15:3705. [Crossref] [PubMed]
14. Sakr M, El-Kerm Y, Abo-Elwafa W, et al. Heterotopic thyroid autotransplantation: A preliminary clinical study. Head Neck 2018;40:34-45. [Crossref] [PubMed]
15. Memarnejadian A, Pakshir P, Tomlinson M, et al. Enhancing post-operative hypothyroidism treatment: rat thyroid autotransplantation into a pre-vascularized, retrievable cell pouch™ device. Front Endocrinol (Lausanne) 2025;16:1642916. [Crossref] [PubMed]
16. Wiseman SM, Memarnejadian A, Boyce GK, et al. Subcutaneous transplantation of human thyroid tissue into a pre-vascularized Cell Pouch™ device in a Mus musculus model: Evidence of viability and function for thyroid transplantation. PLoS One 2022;17:e0262345. [Crossref] [PubMed]
17. Monib S, Habashy H, Ibrahim M. Thyroid autotransplantation after total thyroidectomy in multi-nodular goiter—a case series analysis. Indian Journal of Surgery 2021;83:1451-6.
18. Arraf M, Safia A, Sharabi-Nov A, et al. Association Between Thyroid Gland Volume and Postoperative Hypothyroidism Following Hemithyroidectomy. OTO Open 2026;10:e70239. [Crossref] [PubMed]
19. Ben Hamou A, Marchand JG, Poiree S, et al. Predictors of retreatment after radiofrequency ablation of benign thyroid nodules: role of pre-treatment growth rate and viable volume. Eur Thyroid J 2026;15:ETJ250254. [Crossref] [PubMed]
20. Pavone G, Lamanna E, Pacilli M, et al. Incidental thyroid carcinoma in surgically treated multinodular goiter: a retrospective study. Front Surg 2026;13:1825352. [Crossref] [PubMed]
21. Palaniswamy SS, Subramanyam P. Dual Thyroid Ectopia and Heterotopic Thyroid Autotransplantation. Clin Nucl Med 2020;45:623-5. [Crossref] [PubMed]