A novel laparoscopic assisted mediastinal dissection with gastric tube inversion technique for gastric tube cancer reconstructed through a retrosternal route

Abstract A median sternotomy is often performed in patients with gastric tube cancer reconstructed through the retrosternal route; however, this procedure is invasive and has the risk of severe infectious complications. To overcome these problems, we created a novel method to perform the reconstructed gastric tube resection using a gastric tube inversion technique combined with a laparoscopic mediastinal approach. After the duodenum was divided, the oral side of the cut end was sutured with silken threads for traction. The gastric tube was dissected from the caudal side under a laparoscopic mediastinal approach, whereas the cervical esophagus was taped. After the adhesion between the middle side of the posterior sternum and the reconstructed gastric tube was dissected to the cervix, the gastric tube was inverted by guiding and pulling the thread toward the cervical side. Sharp dissection was facilitated between the inverted gastric tube and the surrounding organs under moderate traction and a favorable surgical view. We have performed this procedure and evaluated the short‐term outcomes in six cases. The laparoscopic mediastinal approach was completed without a median sternotomy in all six cases. Restorable intraoperative lung injury was observed in one case and no major vessel injuries were observed. The postoperative course was satisfactory with a 29.5‐day median length of hospital stay (range, 16‐60 days). The gastric tube inversion technique combined with the laparoscopic mediastinal approach for patients with retrosternal‐reconstructed gastric tube cancer was shown to be safe and less invasive and should be considered in resection of the reconstructed gastric tube.


| INTRODUC TI ON
With the advances in multidisciplinary treatment, the prognosis of esophageal cancer patients who have undergone esophagectomy has improved. [1][2] With the resulting increase in the long-term survival of such patients, the incidence of gastric tube cancer has also increased. [3][4][5] In patients with gastric tube cancer reconstructed through the retrosternal route, a median sternotomy is often performed [6][7][8] ; however, this procedure is invasive and has the risk of severe complications, including sternal dehiscence or mediastinitis. 7,9 Recently, although there have been some reports of procedures without a median sternotomy for patients with retrosternal gastric tube cancer, nearly all of the reports only involve single cases. [7][8][9][10] Herein we report our novel gastric tube inversion technique combined with a laparoscopic mediastinal approach in performing radical total gastric tube resection for patients with gastric tube cancer reconstructed through the retrosternal route.

| Patients
We retrospectively reviewed medical records of patients who underwent total gastric tube resection for gastric tube cancer reconstructed through a retrosternal route at the Aichi Cancer Center Hospital between May 2009 and August 2020. This study was approved by the Review Board of Aichi Cancer Center Hospital (Approval No. ACC 2020-1-672). Regarding the surveillance after esophagectomy, patients received periodic physical and laboratory examinations at 3-month intervals. Computed tomography was performed at 6-month intervals, and endoscopic examination was performed annually in principle.

| Surgical technique
Under general anesthesia, the patient was placed in the supine position. An upper abdominal midline incision was performed ( Figure 1A) and the adhesions around the gastric tube were divided. Following lymph node dissection around the right gastric and right gastroepiploic arteries, the duodenum was dissected using a linear stapler and the gastric side of the stump was sutured with five silken threads for traction. The open wound in the upper abdomen was retracted with a Kent retractor (Takasago Medical Industry Co. Ltd.) to secure the operative field ( Figure 1B). At the entry hole to the retrosternal space, sharp dissection was performed under direct vision between the lower part of the gastric tube and the diaphragm. A collar-shaped skin incision was simultaneously made in the cervix ( Figure 1A), and the cervical esophagus was identified and separated from the surrounding tissues, then the cervical esophagus was taped. We used

| RE SULTS
The patients' clinical characteristics are summarized in Table 1. All of the patients were males. Poorly differentiated adenocarcinoma was the most common pathologic diagnosis. Total gastric tube resections were completed using a laparoscopic mediastinal approach without a median sternotomy in all cases. With respect to intraoperative complications, a pulmonary injury occurred in one case and was repaired using TachoSil ® (CSL Behring KK Japan). No major vessel injuries occurred. The operative outcomes and postoperative complications are summarized in Table 2

| D ISCUSS I ON
This novel gastric tube inversion technique combined with a laparoscopic mediastinal approach was shown to be safe and less inva-  sternum. Therefore, we can safely dissect the anterior aspect of the gastric tube to the cervix. By connecting the dissection to the cervix, we can guide the silken threads to the cervix and perform the gastric tube inversion. When the staple line of the gastric tube is on the anterior aspect, dense adhesions often exist between the gastric tube and the posterior aspect of the sternum. In such cases, it is necessary to perform sharp dissection of the adhesions laparoscopically and it is essential to keep the midline of the sternum intact for the prevention of vascular injury during the dissection. In addition, it is also advisable to perform a full circumferential dissection of the lower half of the gastric tube before inverting the gastric tube. These preparations make it possible to invert the gastric tube. We were able to perform the gastric tube inversion technique in all six cases. Furthermore, we performed sharp dissection with moderate traction under a good surgical view by pulling the inverted gastric tube from the cervical side. As mentioned above, using the laparoscopic mediastinal approach, securing the surgical view and operability in the upper mediastinum can be problematic. Therefore, we believe that our novel gastric tube inversion technique, which can overcome these shortcomings, is useful and safe. This method may not be suitable for large tumors in which the gastric tube cannot be inverted, but in such cases a total gastric tube resection with a median sternotomy may be indicated. Another limitation of this technique is that it is only available when gastric tube cancer is reconstructed by the retrosternal route.
In conclusion, the novel gastric tube inversion technique combined with a laparoscopic mediastinal approach is safe and effective and may become a standardized surgical procedure for gastric tube cancer reconstructed through the retrosternal route.

D I SCLOS U R E
Funding: Authors have no financial ties to disclose.
Conflict of interest: The authors declare that they have no conflicts of interest.