Topographic anatomy of the esophagus after thyroidectomy

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Introduction

One of the most important areas of anatomical research is related to the introduction into clinical practice of such methods of intravital visualization as ultrasound, computed tomography and magnetic resonance imaging [1–4]. They allow studying the intravital anatomy of organs and cavities before and after surgical interventions for various diseases [5]. To date, information has been accumulated on topographic and anatomical changes occurring after surgical operations on the organs of the chest and abdominal cavities, retroperitoneal space [6; 7].

In the work of I.I. Kagan, M.N. Vasyukov (2021), anatomical changes before and after pulmonectomy are described, and topographic and anatomical patterns of post-pneumonectomy changes in the chest cavity are substantiated [8]. P.V. Samoilov (2015) provided data on the topography and anatomy of the mediastinum after the Lewis operation. For this purpose, CT scans of the chest were performed on 115 people without digestive pathology and 40 patients diagnosed with thoracic esophagus cancer. It was found that in the postoperative period, the transverse size of the posterior mediastinum increases and shifts to the right. At the same time, the esophagus expands, the trachea, left main bronchus, aorta and heart shift [9].

A.E. Rykov also studied the anatomy of the mediastinum in normal conditions and in cancer of the thoracic esophagus. The study presents individual, gender, and age-related changes in the anthropometric parameters of the mediastinum and its organs. Thus, the dimensional parameters of the esophagus in men are larger, its location is more lateral, further from the sternum and spine. In people with a brachymorphic chest, the esophagus is larger than in people with a dolichomorphic chest. With age, the lower part of the esophagus expands. In cancer of the thoracic esophagus, the author describes the displacement of the heart forward and to the left, the trachea and left main bronchus forward, the descending thoracic aorta to the left and back [10].

The topography of the retroperitoneal space after nephrectomy was studied by S.V. Chemezov and Yu.V. Monina (2014). It turned out that in the absence of a kidney on the right, the right lobe of the liver, the ascending colon, and the head of the pancreas move into the residual space. After left-sided nephrectomy, the descending colon, pancreas, and spleen shift. It was noted that, in addition to the position, the size and shape of the organs change [11].

An analysis of the literature showed that if there is a clinical and anatomical database after operations on the lungs, thoracic esophagus, and kidney, there is no information in publications about thyroid pathology and radical operations in the neck area. Such studies may be interesting, since the anatomical factors of fixation and stabilization of the neck organs differ from the studied localizations due to the absence of walls and intracavitary pressure. In addition, an assessment of pre- and postoperative changes is necessary to improve surgical technique in repeated operations on the thyroid gland.

The aim of the study is to describe the topographic anatomy of the esophagus before and after thyroidectomy based on the results of magnetic resonance imaging.

Мaterials and Methods

The data of pre- and postoperative magnetic resonance imaging of soft tissues of the neck were studied in 61 patients. Among them were 8 men and 53 women aged from 37 to 75 years. The study included patients diagnosed with multinodular colloid or diffuse-nodular toxic goiter, autoimmune thyroiditis. The organ enlargement was due to uniform damage to both lobes within the neck. The thyroid gland volume according to the ultrasound examination results was over 100 cm³. Dysphagia was reported by 11% of patients. The rest sought medical help due to changes in the neck configuration. All patients underwent thyroidectomy. The postoperative period was uneventful. The studies were conducted after obtaining the patient's informed consent.

The tomograms obtained before surgery and two, six, and twelve months after thyroidectomy were used to evaluate the esophagus topography in three planes: axial, frontal, and sagittal. The quantitative parameters of the organ, its transverse, anteroposterior, and angular dispositions were measured. The displacement was estimated relative to the horizontal and vertical lines drawn through the middle of the body and the anterior edge of the cervical vertebra. Skeletotopically, the section was tied to the sixth, seventh cervical, and first thoracic vertebrae. Additional levels were introduced if necessary. Statistical analysis was performed using the Statistica 6.0 program.

Results & Discussion

When studying preoperative magnetic resonance tomograms of soft tissues of the neck, the topography of the cervical esophagus corresponded to the classical concepts of the surgical anatomy of the organ. Despite the significant volume of the thyroid gland, no displacement or compression of the esophagus was detected (Fig. 1).

 

Fig. 1. Patient K., 44 years old. Diagnosis: multinodular colloid goiter, euthyroidism. Thyroid gland volume is 173 cm³. There is no displacement or compression of the esophagus

 

An assessment of tomographic sections 12 months after surgery made it possible to determine a change in the shape of the lumen of the esophagus due to an increase in its anteroposterior size and the displacement of the organ to the left lateral wall of the trachea (Fig. 2).

 

Fig. 2. Patient K., 44 years old. Diagnosis: multinodular colloid goiter, euthyroidism. Thyroid gland volume 173 cm³. Condition 12 months after thyroidectomy. Esophagus located at the left lateral wall of the trachea. Increased anteroposterior size of the esophagus

 

The lumen of the esophagus increased in the anteroposterior direction in the postoperative period. The preoperative median of this parameter was 0.37 cm. Two months after thyroidectomy, it also corresponded to the preoperative values. However, six months after surgery, its increase was observed by an average of 1.3 cm. After six months, the median of the anteroposterior size of the organ increased 4-fold, after 12 months – 6-fold, which significantly exceeds the preoperative values (Wilcoxon T-test, p ≤ 0.01). The organ acquired a spherical shape (Table 1).

 

Table 1

Comparison of median anteroposterior esophageal diameters before surgery,two, six and 12 months after intervention

Cut-off level	Median anteroposterior size of the esophagus, cm				Wilcoxon T-test
	Before surgery	Two months after the surgery	Six months after the surgery	Twelve months after the surgery
С VI (sixth cervical vertebra)	0.37	0.45	1.8*	2.3**	*p ≤ 0.01 ** p ≤ 0.01
С VII (seventh cervical vertebra)	0.34	0.4	1.76*	2.6**	*p ≤ 0.01 ** p ≤ 0.01
Th1 (first dorsal vertebra)	0.4	0.48	1.74*	1.96**	* p ≤ 0.01 ** p ≤ 0.01

Note: here and in Tables 2, 3: * p ≤ 0.01 (Wilcoxon T-test) – parameter six months after surgery relative to preoperative value; **p ≤ 0.01 (Wilcoxon T-test) – parameter 12 months after surgery relative to preoperative value.

 

Simultaneously with the expansion of the esophagus, its displacement to the left lateral wall of the trachea occurred. Before the surgery, the median displacement relative to the vertical axis was 0.32 cm. Two months after the surgery, it increased to 0.41 cm, six months later – to 1.1 cm, and 12 months later – to 2.12 cm. The displacement of the esophagus along the horizontal axis to the left was observed from the second month of the postoperative period, and in 73 % of cases, one year after thyroidectomy, the esophagus was located parallel to the trachea (Tables 2, 3).

 

Table 2

Median esophageal displacement relative to the vertical axis before surgery, two, six and 12 months after the intervention

Cut-off level	Median displacement of the esophagus along the vertical axis, cm				Wilcoxon T-test
	Before surgery	Two months after the surgery	Six months after the surgery	Twelve months after the surgery
С VI (sixth cervical vertebra)	0.3	0.42	0.9*	2.0**	* p ≤ 0.01 ** p ≤ 0.01
С VII (seventh cervical vertebra)	0.39	0.49	1.1*	2.4**	* p ≤ 0.01 ** p ≤ 0.01
Th1 (first dorsal vertebra)	0.42	0.62	1.4*	1.98**	* p ≤ 0.01 ** p ≤ 0.01

 

Table 3

Median esophageal displacement relative to the horizontal axis before surgery

Cut-off level	Median displacement of the esophagus along the vertical axis, cm				Wilcoxon T-test
	Before surgery	Two months after the surgery	Six months after the surgery	Twelve months after the surgery
С VI (sixth cervical vertebra)	0.14	0.24	0.73*	0.83*	* p ≤ 0.01 ** p ≤ 0.01
С VII (seventh cervical vertebra)	0.11	0.26	0.62*	0.64*	* p ≤ 0.01 ** p ≤ 0.01
Th1 (first dorsal vertebra)	0.21	0.27	0.71*	0.79*	* p ≤ 0.01 ** p ≤ 0.01

 

The literature contains isolated publications on the topographic anatomy of the thyroid gland with an increase in its volume [12]. We did not find any information on postoperative changes in the topography of the neck organs after thyroidectomy. The anatomical changes that were discovered are probably associated with intraoperative destruction of the connective tissue structures that connect the thyroid gland with other organs and fix the posterior surface of the organ to the larynx, trachea, and esophagus.

Conclusions

During the year after thyroidectomy, changes in the shape, diameter and topography of the cervical esophagus occur. Twelve months after thyroidectomy, the anteroposterior size of the esophagus increases sixfold compared to the preoperative size, and it shifts toward the left lateral wall of the trachea relative to the vertical axis by 2.12 cm. The results obtained may be useful for repeated surgical interventions in this area.

About the authors

A. S. Zhirnova

Orenburg State Medical University

Author for correspondence.
Email: oringirl@mail.ru

PhD (Medicine), Associate Professor of the Department of General Surgery

 

Russian Federation, Orenburg

O. M. Abramzon

Orenburg State Medical University

Email: oringirl@mail.ru

DSc (Medicine), Professor of the Department of General Surgery

Russian Federation, Orenburg

S. N. Lyashchenko

Orenburg State Medical University

Email: oringirl@mail.ru

DSc (Medicine), Professor, Head of the Department of Operative Surgery and Clinical Anatomy

Russian Federation, Orenburg

References

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