Upgraded bidirectional approach video-assisted neck surgery (BAVANS) using a rigid endoscope with variable viewing direction for advanced endoscopic lymph node dissection in thyroid cancer patients
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In 2011, we developed bidirectional approach video-assisted neck surgery (BAVANS) for endoscopic thyroid cancer surgery. BAVANS combines two different approach pathways at 180 degrees to the cervical lesion for endoscopic thyroidectomy and complete cervical lymphadenectomy. We reported previously that the cranio-caudal approach is extremely useful for endoscopic complete lymph node dissection around the trachea. In 2014, we upgraded the initial BAVANS for better maneuverability and quality of lymph node dissection. A new high-tech rigid endoscope with a variable viewing direction (EndoCAMeleon™), has enabled us to reduce the camera port in the anterior neck while keeping the easy maneuverability and the same quality of central lymph node dissection (LND) as with the initial BAVANS. Endoscopic thyroid cancer surgery is now evolving concurrently with new visual technology.
KeywordsBAVANS Video-assisted neck surgery Lymph node dissection
Body position and setting of the equipment
The patient is placed in the supine position with slight neck extension achieved by a shoulder pillow, under general endotracheal anesthesia. Because the surgeon must be positioned over the head of the patient and have access to the central node from the submandibular neck area for the second half of surgery, the anesthetic equipment is set up to the right of the patient.
Upgraded BAVANS procedure
First, total or hemithyroidectomy is performed, followed by LND of the upper part of the central node via a gasless precordial (or axillary) approach using a 5 mm oblique tip endoscope with a 30° angle. When performing thyroidectomy, the axillary approach or areolar approach is possible, but we generally select a precordial approach with modification of the video-assisted neck surgery (VANS) technique developed by Shimizu et al. . In the precordial approach, a 3-cm skin incision is made in the right anterior chest area, 6 cm beneath the inferior margin of the clavicle, as well as a 5-mm camera port incision in the left side. (Fig. 2b). Dissection is performed along with the subplatysmal layer, extending up to the level of the neck wrinkle above the thyroid cartilage. Laterally, this dissection can be continued up to the medial border of the sternocleidomastoid muscle on the tumor side, and up to the contralateral internal borderline of the sternocleidomastoid muscle in patients undergoing lobectomy. In total thyroidectomy, lateral dissection is extended up to the medial borderline of the sternocleidomastoid muscles on both sides. After dissection of the subplatysmal plane, a mistless VANS retractor is inserted through the right main incision and elevated by the retracting wire system fixed to the pole above the patient’s neck. Pulling the strap muscles laterally with an exclusive detachable wire retractor creates an excellent visual field and working space. Following dissection around the thyroid gland, all the vessels, including the upper and lower thyroid arteries and veins, are transected by using ultrasonic coagulating shears. The recurrent laryngeal nerve and outer branch of the superior laryngeal nerve are identified and isolated by using a nerve integrity monitoring system (NIM-Response® 3.0). More details are provided in our previous article describing BAVANS .
Dissection of the upper part of the central node
After thyroidectomy, LND of the upper part of the central nodes (upper area in level VI) is performed by extending the precordial approach. Here, the upper part of the central node refers to the lymph node located above the horizontal line, 2 cm beneath the inferior border of the cricoid cartilage.
Dissection of the lower part of the central node
The average operating times for the upgraded BAVANS were 193 min and 245 min in the hemithyroidectomy with unilateral central node dissection (CND) group and the total thyroidectomy with bilateral CND group, respectively. The mean blood loss with the upgraded BAVANS was 26 ± 16.4 ml (n = 5) for total thyroidectomy with bilateral CND and 15.6 ± 26.8 ml (n = 46) for hemithyroidectomy with unilateral CND. The average number of harvested lymph nodes in unilateral and bilateral CND was 10 ± 4.5 (n = 8) and 7.4 ± 3.8 (n = 5), respectively, in the initial BAVANS vs. 9.2 ± 6.1 (n = 46) and 15.2 ± 8.5 (n = 6), respectively, in the upgraded BAVAS.
The combination approach of two different directions is a useful and promising surgical procedure for complete lymph node dissection in thyroid cancer surgery. In particular, the cranio-caudal approach is effective for lymphadenectomy of the lower paratracheal area and the supraclavicular area. The introduction of a new rigid endoscope featuring variable viewing direction improves the efficiency of BAVANS. If this rigid “Endowrist” camera is introduced into a medical robot system represented by DaVinci, its working range and validity will be further expanded. Endoscopic thyroid surgery involving robotics will advance with new developments in visual technology and surgical instruments.
Compliance with ethical standards
Conflict of interest
Akihiro Nakajo and his co-authors have no conflicts of interest to declare regarding the publication of this article.
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