Parathyroid Vascular Anatomy Using Intraoperative Mapping Angiography: The Paratlas Study

Endocrinology Medicine
parathyroid vascular anatomy thyroidectomy vessel distribution intraoperative mapping

Academic Background

The preservation of the parathyroid glands (PGs) during thyroidectomy is crucial, as postoperative hypoparathyroidism is a common complication of thyroid surgery, particularly after total thyroidectomy. Approximately 30%-40% of patients experience transient hypoparathyroidism, with 5%-10% developing permanent hypoparathyroidism. The primary cause of hypoparathyroidism is intraoperative damage to the blood supply of the parathyroid glands. However, current research on the vascular anatomy of the parathyroid glands is mostly based on cadaveric dissections or intraoperative observations, resulting in fragmented and non-systematic information. Additionally, there is no dedicated anatomical atlas to provide surgeons with a visual guide to the vascular distribution of the parathyroid glands.

To address this gap, this study aims to systematically describe the distribution patterns of parathyroid vessels using intraoperative mapping angiography (IMAP) combined with indocyanine green (ICG) fluorescence imaging, and to construct an anatomical atlas of parathyroid vessels for surgical guidance.

Source of the Paper

This paper was co-authored by Fares Benmiloud (Endocrine Surgery Unit, Hôpital Européen Marseille, France), Neil Tolley (Endocrine Surgery Service, Imperial College Healthcare NHS Trust, London, UK), Anne Denizot (Endocrine Surgery Unit, Hôpital Européen Marseille, France), Aimee Di Marco (Endocrine Surgery Service, Imperial College Healthcare NHS Trust, London, UK), and Frédéric Triponez (Department of Thoracic and Endocrine Surgery, University Hospitals and Faculty of Medicine of Geneva, Switzerland). The paper was published in 2025 in the British Journal of Surgery (BJS), with the DOI: https://doi.org/10.1093/bjs/znae307.

Research Process

Study Design and Participants

This study retrospectively analyzed 200 real-time angiography images obtained from thyroid surgeries performed between February 2020 and September 2021 at Hôpital Européen Marseille, France. All patients underwent thyroid lobectomy or total thyroidectomy, with some also undergoing lymph node dissection. The angiography technique was based on ICG injection and fluorescence imaging (Fluobeam LX, Fluoptics, Grenoble, France).

Intraoperative Angiography Technique

During the surgery, the surgeon used 2.5x magnification, a neuromonitoring system, and a fluorescence imaging system. ICG solution (Infracyanine Serb, France) was injected intravenously at a dose of 1 ml (2.5 mg), and the angiography images were recorded using the Fluobeam LX system. The images were reviewed in slow motion, and the vascular tree structure was manually drawn by the surgeon to simplify the complexity of the images and highlight the relationship between the parathyroid vessels and the thyroid gland.

Classification of Vascular Patterns

Based on the contact patterns between the parathyroid vessels and the thyroid gland, the researchers classified the vessels into seven types: - Type 0: No contact with the thyroid, easy to preserve. - Type 1: Single-point contact with the thyroid, moderate difficulty in preservation. - Type 2: Posterior pathway along the thyroid, potentially high difficulty in preservation. - Type 3: Lateral pathway along the thyroid, potentially high difficulty in preservation. - Type 4: Intrathyroidal pathway, very high difficulty in preservation. - Type X1: Possible medial pathway along the thyroid, very high difficulty in preservation. - Type X2: Unknown pathway.

Data Collection and Analysis

The study collected data on patient gender, age, surgical indications, extent of surgery, and postoperative complications (e.g., hypoparathyroidism, recurrent laryngeal nerve palsy, compressive hematoma). The quality of the angiography images was classified into IMAP2 (clear visualization of parathyroid vessels), IMAP1 (only providing information on vessel distribution), and IMAP0 (no relevant information). Statistical analysis was performed using SAS 9.4 software, with quantitative data expressed as mean ± standard deviation and qualitative data expressed as frequency and percentage.

Main Results

Vascular Distribution Patterns

Among the 320 parathyroid glands analyzed, the vascular distribution patterns were as follows: - Type 0: 6% (20 glands). - Type 1: 23% (74 glands). - Type 2: 15% (47 glands). - Type 3: 21% (68 glands). - Type 4: 6% (19 glands). - Type X1: 8% (26 glands). - Type X2: 11% (36 glands).

Spatial Distribution Analysis

The superior parathyroid vessels were mainly concentrated around Zuckerkandl’s tubercle, while the inferior parathyroid vessels were more dispersed and anteriorly located. Vascular density analysis showed that the superior parathyroid vessels had a higher density at the posterior edge of the thyroid, while the inferior parathyroid vessels had a broader distribution area.

Postoperative Complications

Among the 159 patients who underwent total thyroidectomy, 8 (5%) had a parathyroid hormone (PTH) level below 10 pg/ml on postoperative day 1, with 3 (2%) developing hypocalcemia and receiving calcium and/or vitamin D treatment. All patients recovered within one month. Additionally, 8 patients experienced unilateral transient recurrent laryngeal nerve palsy (2% of 366 nerves), with no cases of hemorrhage.

Conclusions and Significance

This study systematically described the distribution patterns of parathyroid vessels using intraoperative mapping angiography and constructed an anatomical atlas of parathyroid vessels for surgical guidance. The results indicate that the contact patterns between parathyroid vessels and the thyroid gland are diverse, with most vessels in contact with or running over (and sometimes into) the thyroid. This finding emphasizes the importance of preserving parathyroid blood supply during thyroidectomy and provides surgeons with a visual anatomical reference.

Scientific Value

This study fills the gap in research on the vascular anatomy of the parathyroid glands, providing a systematic classification and distribution analysis based on intraoperative imaging, and offers scientific evidence for parathyroid preservation during thyroidectomy.

Clinical Value

The findings can be directly applied to clinical surgery, helping surgeons identify and preserve parathyroid vessels, thereby reducing the incidence of postoperative hypoparathyroidism.

Research Highlights

  1. Innovative Technique: First application of intraoperative mapping angiography to study the vascular anatomy of the parathyroid glands, providing real-time, dynamic information on vessel distribution.
  2. Systematic Classification: First systematic classification of the contact patterns between parathyroid vessels and the thyroid gland, offering clear guidance for vascular preservation during surgery.
  3. Clinical Utility: The findings can be directly applied to clinical practice, helping surgeons optimize surgical procedures and reduce postoperative complications.

Additional Valuable Information

The study also found that some parathyroid glands had already lost their blood supply at the time of the first ICG injection, suggesting that vascular damage may have occurred in the early stages of surgery. This finding reminds surgeons to pay more attention to preserving parathyroid blood supply during surgery, especially when handling the upper and lower thyroid pole vessels.

This study provides important anatomical evidence and technical support for parathyroid preservation during thyroidectomy, with significant clinical and scientific value.