PMC5458621_01
(A) Tilepro image of ultrasound use prior to starting dissection. A large blood vessel is seen in the deep lateral portion of the planned dissection (arrow). (B) Preoperative computed tomography scan of this patient shows vasculature in the area of dissection (arrows). (C) Following vessel identification, initial dissection proceeds as planned to excise the tumor.
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F1
Additionally, pulsation of the carotid system could be seen along the left pharyngeal wall in the area of this lesion, and vessels could be seen deep to this tumor using the ultrasound probe (Figure 1A). While vessels in the area of dissection were seen on preoperative computed tomography (CT) scans (Figure 1B), these scans do not provide the same correlation to the intraoperative view as the real-time ultrasound imaging. Surgical dissection was performed using monopolar cautery to initially define the superior, lateral, and inferior boundaries of dissection until the constrictor muscle was encountered (Figure 1C).
(A) After initial dissection, the ultrasound is used to visualize the large blood vessel near the plane of resection (arrow). (B) Careful dissection in the area identified on ultrasound leads to identification and preservation of the artery (arrow).
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F2
Given the risk of vascular injury in this area, a hockey stick ultrasound probe was then placed into the tumor bed, allowing for visualization of a large artery just deep to the plane of dissection (Figure 2A). With this information, dissection proceeded, and the vessel was safely identified without injury in the area predicted by the ultrasound (Figure 2B).
(A) After resection of the tumor, the ultrasound again identifies several large blood vessels within the parapharyngeal space just lateral and deep to the surgical bed. (B) Final surgical defect.
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F3
At the conclusion of the dissection, large-caliber vessels in the parapharyngeal space, including the carotid artery, could be clearly seen using the ultrasound within the wound bed (Figure 3).
PMC5458621_02
(A) Intraoperative ultrasound still from patient No. 2 demonstrating the tongue base squamous cell carcinoma, with an echogenic line (white arrow) indicating the interface between tumor and adjacent normal tissue. Tumor thickness was measured to be 1.36 cm. (B) After removal from the patient, the tumor specimen was sectioned and measured. The tumor margin is marked with a black arrowhead; the overall tumor thickness was found to be approximately 1.3 to 1.4 cm.
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F4
TORS resection, the ultrasound was used to examine the tumor (Figure 4A). Once the tumor was removed, the specimen was examined, and the tumor margin was clearly seen as demonstrated previously by the ultrasound, and the tumor thickness was noted to be similar to that measured by ultrasound (Figure 4B).