Situs inversus totalis (SIT) is a rare congenital anomaly with complete inversion of the viscera 1 . The altered anatomical position of the organs can cause great technical challenges in endoscopic procedures 2 .
A 33-year-old man underwent endoscopic ultrasonography (EUS) in our center. Computed tomography (CT) revealed a mirror image of the normal anatomy with complete inversion of the viscera ( Fig. 1 ). We used linear array EUS to examine the bile duct and pancreas. The process was successfully completed, with many differences compared with normal patients ( Video 1 ).
Fig. 1.
Computed tomographic image of a patient with situs inversus totalis.
Video 1 Process of linear array endoscopic ultrasonography in a patient with situs inversus totalis.
The patient lay in the left lateral position. In the stomach, the scan was similar to common EUS tracing the splenic artery and vein. Contrary to normal patients, the clockwise-rotating scan with pushing of the endoscope ranged from the tail of the pancreas to the head of the pancreas. The order of scanning markers on the screen from left to right changed from portal confluence, left kidney, left adrenal gland, and spleen to spleen, left kidney, left adrenal gland, and portal confluence.
We rotated the endoscope to the left and pushed along the lesser curvature of the stomach to reach the duodenal bulb ( Fig. 2 ). The direction of turn from the bulb to the descending segment of the duodenum changed from right to left ( Fig. 3 ). We pushed the endoscope, adhering to the anterior wall of the duodenal bulb, to scan the common bile duct.
Fig. 2.
Stomach cavity: the mirror image of normal.
Fig. 3.
Duodenal bulb: the mirror image of normal.
We rotated the endoscope carefully to the left and pushed it to the descending segment. The scanned image of the descending segment was the opposite of what is seen in the normal person, and the pancreatic uncinate process appeared on the left side of the screen.
EUS in the patient with SIT brings technical difficulties. For patients with SIT, doctors need to change the operating habits and skills formed through working in people with normal anatomy, and operating methods also need to be more precise.
Endoscopy_UCTN_Code_CCL_1AF_2AZ_3AD
Acknowledgments
Jun Yao is supported by the National Natural Science Foundation of China (no. 81800489).
Footnotes
Competing interests The authors declare that they have no conflict of interest.
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References
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