|Year : 2014 | Volume
| Issue : 4 | Page : 985-990
Esophageal suspension method in scavenging peripheral lymph nodes of the left recurrent laryngeal nerve in thoracic esophageal carcinoma through semi-prone-position thoracoscopy
Wei Zheng, Yong Zhu, Chao-Hui Guo, Bin Zheng, Zi-Yang Han, Chun Chen
Department of Thoracic Surgery, The Affiliated Union Hospital of Fujian Medical University, Fuzhou 350001, China
|Date of Web Publication||9-Jan-2015|
Department of Thoracic Surgery, The Affiliated Union Hospital of Fujian Medical University, No. 29 Xinquan Road, Fuzhou 350001
Source of Support: None, Conflict of Interest: None
Objective: Many Chinese doctors have performed microinvasive esophageal cancer resection in the semi-prone position. However, few reports have focused on high-quality methods of scavenging the peripheral lymph nodes (PLNs) of the left recurrent laryngeal nerve (RLN).
Materials and Methods: Retrospective analysis was performed on 145 cases of microinvasive esophageal cancer resection in the semi-prone position. Among which, 75 cases underwent complete freeing of the thoracic esophagus and subsequent scavenging of the PLNs of the left RLN from April 2011 to April 2012 (Group A). In the other 70 cases, the incompletely freed upper thoracic esophagus was suspended, and the PLNs of the left RLN were scavenged from May 2012 to April 2013 (Group B).
Results: The average number of scavenged PLNs of the left RLN in Groups A and B was 4.6 ± 2.9 and 5.2 ± 3.0 pieces, respectively (P = 0.799). The total scavenged PLNs of the left RLN in Groups A and B were 344 and 357 pieces, respectively. Among which, the broken lymph nodes were 109 and 66 pieces, respectively (P < 0.0001). The postoperative hoarseness rate in Groups A and B was respectively 12.0% and 2.8% (P = 0.038).
Conclusions: Dissection of the left RLN can be easily performed after esophageal suspension, thus ensuring the quality of PLN scavenging.
结果：平均左喉返神经外周淋巴结清除数量，A和B组分别为4.6± 2.9和5.2± 3（P = 0.799）。总左喉返神经外周淋巴结清除数量，A和B组分别为344和357。其中，破碎的淋巴结分别为109和66（P＜0.0001）。A和B组分别有12%和2.8%术后声音嘶哑率（P = 0.038）。
Keywords: Esophageal cancer, lymph node scavenging, recurrent laryngeal nerve, thoracoscope
|How to cite this article:|
Zheng W, Zhu Y, Guo CH, Zheng B, Han ZY, Chen C. Esophageal suspension method in scavenging peripheral lymph nodes of the left recurrent laryngeal nerve in thoracic esophageal carcinoma through semi-prone-position thoracoscopy. J Can Res Ther 2014;10:985-90
|How to cite this URL:|
Zheng W, Zhu Y, Guo CH, Zheng B, Han ZY, Chen C. Esophageal suspension method in scavenging peripheral lymph nodes of the left recurrent laryngeal nerve in thoracic esophageal carcinoma through semi-prone-position thoracoscopy. J Can Res Ther [serial online] 2014 [cited 2020 May 27];10:985-90. Available from: http://www.cancerjournal.net/text.asp?2014/10/4/985/144354
| > Introduction|| |
With the development of endoscopic techniques in the past decade, the feasibility and safety of microinvasive esophageal cancer resection has been increasingly recognized by doctors due to its advantages, including minimal trauma, minimal bleeding, low postoperative mortality, low incidence of respiratory complications, and short hospital stay.,,,, The metastasis rate of the peripheral lymph nodes (PLN) of the recurrent laryngeal nerve (RLN) is high in esophageal cancer patients. Several Japanese scholars reported the metastasis to be ranging from 18.0% to 43.4%. , A significant correlation between the RLN-PLN metastasis and the cervical lymph node metastasis has also been reported.  Therefore, thorough lymph node dissection not only reduces the recurrence of the local lymph node,  but also helps improve the postoperative survival rate. ,, Nevertheless, this type of dissection has high technical requirements. Therefore, the incidence of associated complications is also high, which could range from 41.7% to 75.3%, respectively. 
Regardless of the posture, thorough cleaning of the PLN of RLN and avoiding nerve injury are among the main difficulties in minimally invasive surgery for esophageal carcinoma because of the anatomical position of the left RLN. To improve the cleaning effect on the PLN of the left RLN, we conducted thoracoscopic esophageal cancer resection in the lateral prone position. We scavenged the PLN of the left RLN after complete freeing of the thoracic esophagus (nonsuspension method) and found that this method performs poorly in exposing the tissues in the left RLN region. From May 2012, we performed the above dissection after suspending the incompletely freed upper thoracic esophagus (suspension method). We found that this method can expose the tissues in the left RLN region satisfactorily, thus improving the cleaning quality of the PLN of the left RLN.
| > Materials and methods|| |
Patients and grouping
Retrospective analysis was performed on patients who underwent thoracoscopic esophageal cancer resection and thoracic lymph node dissection in the lateral prone position from April 2012. Prior to this, the treatment group had completed more than 100 cases of thoracoscopic esophageal cancer resection in the lateral prone position. The patients who first underwent complete freeing of the thoracic esophagus, followed by scavenging of the left RLN-PLN from April 2011 to April 2012, were assigned to Group A (nonsuspension method). The patients who first underwent suspension of the incompletely freed upper thoracic esophagus, followed by scavenging of the left RLN-PLN from May 2012 to April 2013, were assigned to Group B (suspension method). All patients underwent gastroscopy to confirm the esophageal cancer, with the pathological types being squamous carcinoma or adenosquamous carcinoma. The patients also underwent cervical lymph node B ultrasound, ventrum computed tomography (CT) normal and enhanced scan, or total body positron emission tomography-CT examination.
The clinical stage was in T1-3N0-1M0 (the staging criteria were according to the International tumor-node-metastasis [TNM] Staging of Esophageal Cancer, 7 th edition, 2009), without fused and integrated swelled lymph nodes. The patient did not receive preoperative adjuvant therapy (including chemotherapy and radiotherapy), had no previous history of cancer, tuberculosis, and silicosis and had no previous history of thoracic surgery except for the thoracic surgery cases due to intraoperative bleeding or intraconversed from tumor outward invasion. A total of 75 and 70 patients in Groups A and B met the above criteria, respectively.
Thoracic surgery procedure
Under general anesthesia, the patients underwent double-lumen endotracheal intubation into the right main bronchus of the left lung for one-lung ventilation. The patient was in the lateral prone position; the right chest side was elevated about 45°; the left upper arm protracted forward, forming 90° with the body; and the right upper arm protracted forward forming 120° with the body and was placed on the head side [Figure 1]. The chief doctor and the endoscope-operating doctor stood in the ventral side of the patient. The seventh intercostal skin along the right axillary midline was incised and implanted into the 12 mm trocar. CO 2 was injected (CO 2 pressure: 6-8 mm Hg) to establish artificial pneumothorax. The right lung then collapsed. The thoracoscope was placed inside the lung to observe whether pleural adhesions were present in the thoracic cavity. The positions of the three other trocars were as follows: A 12 mm trocar was placed in the fourth intercostal along the right axillary midline; 2-5 mm trocars were placed in the sixth and eighth intercostal along the right infrascapular line. An endoscopic electric hook, ultrasound knife, grasping forceps, isolating forceps, or suction could be implanted depending on the operating needs. First, the esophageal anterior and posterior mediastinal pleurae were opened to detect tumor. The azygos vein arch was then double-clamped with Hem-o-lock and cut-off with an ultrasound knife by using an electric hook or ultrasound knife to free the esophagus and para-esophageal lymph node. The right RLN-PLN was first scavenged: The mediastinal pleura was opened along the right vagus nerve and the right subclavian artery surface. The right RLN could be observed when the junction of the vagus nerve and the subclavian artery was bluntly dissected with isolating forceps. After freeing the right RLN, an electric hook or an ultrasound knife was used to resect the PLN and soft tissues, and the upper edge scavenged should be close to the anus perineum of the thyroid pole. Subsequently, the left RLN-PLN was dissected. The carina-inferior lymph nodes, para-left main bronchus lymph nodes, and diaphragm-superior lymph nodes were finally dissected. The thoracic esophagus was not cut-off during the operation.
The middle and lower esophagus were fully freed, with the upper edge parallel to the arch of the azygos vein. The arch of the azygos vein was cut-off, and both sides of the mediastinal pleura of the upper thoracic esophagus were cut-off. In the anterior part, the tissues between the esophagus and the membranous parts of the trachea were freed until the left edge of the left main bronchus was reached. In the posterior part, the tissues between the esophagus and the spine were freed, and the thoracic duct was fully exposed. Number 7 silk was used to suspend the middle and lower esophagus. Subsequently, the suspension line was punctured out from the fifth intercostal space of the scapular inner edge by using the perforator. An electric hook was used to perform full freeing in the area close to the trachea and the left edge of the left main bronchus. The assistant used grasping forceps to push aside the lower trachea. The left side of the left main bronchus wall was pushed forward and downward to fully reveal the surgical field of the esophagus-trachea groove and the aortic arch [Figure 2]a. The PLN and soft tissues of the aortic arch and left RLN were freed. The inferior lymph nodes of the aortic arch were first scavenged. Dissection close to the inferior anatomy of the aortic arch was performed, and the sympathetic cardiac branch and left RLN were identified. The left RLN sharply separated to the level of the chest from bottom to top, which required cutting of two to three branches during the separation process. The upper thoracic esophagus was completely freed, and the PLN and soft tissues surrounding the left RLN from the upper thoracic esophagus were isolated [Figure 2]b. Earlier, we placed the left-sided double-lumen endotracheal tube. However, poking the left lower tracheal wall and exposing the surgical field were laborious. Therefore, we adopted the right-sided double-lumen endotracheal tube and found that poking the left lower tracheal wall and exposing the surgical field were easy. Before operation, the main trachea and the right bronchus cuff were relaxed, allowing temporary air leakage, while observing blood oxygen saturation and heart rate. This procedure was performed to avoid protuberance of the tracheal membrane that may affect vision and the operation and to reduce the opportunities of accidentally injuring the membrane during operation.
The thoracic esophagus was completely freed. Afterward, the esophagus was pulled to the front. An electric hook was used to fully free the area close to the trachea and the left edge of the left main bronchus. The assistant used a pair of grasping forceps to push forward the left side wall of the lower trachea. The lymph nodes and soft tissues beneath the aortic arch were first scavenged. The grasping forceps were used to lift the lymph nodes and soft tissues. Dissection close to the bottom of the aortic arch was performed, and the left RLN was identified. The RLN was dissected and freed from the bottom up to the chest level and was separated from the lymph nodes.
SPSS 15.0 software package was applied in the analysis. Student's t-test and χ test were performed to determine whether the difference was significant, with P < 0.05 considered as statistically significant.
| > Results|| |
Clinical characteristics of patients
A total of 75 patients in Group A and 70 patients in Group B participated in the study. The tumor characteristics of the patients of both groups were summarized in [Table 1]. According to International TNM Staging of Esophageal Cancer, the diagnoses were determined to be advanced tumor invasion (7 th edition, 2009). No significant difference was present in terms of age, sex, tumor location, invasion depth, and pathological types between the two groups.
The length of thoracic surgery, lymphadenectomy conditions, and recognition rates of the sympathetic cardiac branch of the two groups were summarized in [Table 2]. The length of thoracic surgery in Group A was 109.8 ± 20.5 min. Although the length of the surgery is longer in Group A than in Group B (105.0 ± 21.1 min), the difference in length was not statistically significant (P = 0.885). The average number of lymph node dissection of each case in Group A was 4.6 ± 2.9 pieces, which was less than that in Group B (5.2 ± 3.0 pieces); nevertheless, the difference was not statistically significant (P = 0.799). The total number of left RLN-PLN dissected in Group A was 344 pieces, among which 109 pieces were broken, with the breaking rate being 31.7%. The total number of left RLN-PLN dissected in Group B was 357 pieces, among which 66 pieces were broken, with the breaking rate being 18.5%. Statistically significant difference (P < 0.0001) was observed. In Group B, 69 cases (97.2%) have clearly identifiable sympathetic cardiac branch, whereas in Group A, number of patients having the same characteristic is 48 (64.0%). This difference between the two groups was statistically significant (P < 0.0001). Selective cervical lymph node scavenging was performed in 30 patients in Group A and 28 patients in Group B. The scavenging cases and metastasis are shown in [Table 3].
The complication occurrence is summarized in [Table 4]. The overall incidence of postoperative complications in Group A was 30.7% (23/75), which is higher than that in Group B (18.6%, 13/70); nevertheless, the difference was not statistically significant (P = 0.093). No statistical significance in the incidence of chylothorax and anastomotic leakage was observed in the two groups. For patients with postoperative hoarseness, routine fiberoptic bronchoscopy was conducted within 7 postoperative days. An obstacle in moving the unilateral vocal cord was observed, which indicated the side of RLN damage. The incidence of postoperative hoarseness in Group B was 2.8% (2/70), which is lower than that in Group A (12.0%, 9/75), with the difference being statistically significant (P = 0.038). This finding was mainly attributed to the fact that the left RLN injury rate of Group B was significantly lower than that of Group A. The associated pneumonia incidence in Group B was 7.1% (5/70), which is lower than that in Group A (13.3%, 10/75); nevertheless, the difference was not statistically significant (P = 0.223).
| > Discussion|| |
Certain literature has reported that microinvasive esophagectomy in the prone position has better surgical field exposure than the left lateral position has. Microinvasive esophagectomy can reduce surgery fatigue of doctors due to laparoscopic posture, can shorten the operative time, and can reduce bleeding, among others. , The technique could also better reveal the left RLN;  nevertheless, its largest drawback is that during emergency cases, which require position changes and thoracotomy, difficulties arise.  Therefore, the prone position is unsuitable for situations closely associated with the blood vessels and trachea membrane and in esophageal cancer patients who received neo-adjuvant chemotherapy. , After the performance of an artificial pneumothorax in the semi-prone position, microinvasive esophageal cancer resection may have some advantages. Given that a collapsed lung naturally falls forward, the esophageal bed could achieve better exposure. This phenomenon, coupled with the pressure of the artificial pneumothorax, can help the dissecting spaces surrounding the esophageal tissues become clearer. In addition, conducting thoracotomy during emergency situations and handling simple lung diseases simultaneously become easier. Therefore, microinvasive esophageal cancer resection with this body posture is being increasingly accepted by more Chinese doctors. We have encountered the technique in three patients who were preoperatively judged to be in the T3 stage. Intraoperative exploration revealed that the tumors of two patients invaded into the descending aorta, and the tumor of the other patient was closely adhesive with the tracheal membrane. In these three patients, the surgery was successfully performed without changing position while conversing to posterolateral thoracotomy. Endoscopic esophageal cancer surgery was chosen more frequently in T1-T3 patients. Tumor resection was performed without difficulty because of mediastinal lymph node dissection. The quality of the mediastinal lymph node dissection is an important factor that affects postoperative survival rate. ,, The quality of mediastinal lymph node dissection mainly depended on whether the massive resection could be performed toward the left and right RLN-PLN. In the semi-prone position, the right RLN was at the junction of the right vagus nerve and right subclavian artery. In this position, the right RLN is easy to be recognized and exposed, and the lymph node dissection can be formed easily. The left RLN wound beneath the aortic arch extended upward along the trachea and esophageal sulcus; the distance was long, and the position was deep and difficult to be exposed. PLN dissection is susceptible to damaging the nerves and cause hoarseness, resulting in postoperative weak expectoration, lung infection, as well as aspiration and choking, which will seriously affect the patient's quality of life. Thus, the quality of the left RLN-PLN dissection is the key to successful endoscopic esophageal cancer resection in the semi-prone position.
Good exposure of the left mediastinal surgical field is the prerequisite for high-quality cleaning of the PLN of the left RLN. In the suspension method, because of the suspension of the esophagus, the generated tension will pull the left RLN and the surrounding lymph nodes backward and upward along the esophagus. Therefore, the position will become superficial and recognizing and freeing the left RLN will be easier. The assistant could use the grasping forceps to pull the left wall of the lower trachea, forming tension and making the surgical field of this region wider. Therefore, the anatomy of the tissue structure in this region can be determined easily. In addition, the suspension can save the instrument from stretching, and the chief surgeon could operate through two instruments in this large space. Compared with the nonsuspension method, the suspension method allows for easier exposure and identification of the sympathetic cardiac branch, which originated from the neck and descended along the left subclavian artery. All of these reasons provided us with a strong foundation in performing the massive resection of the left RLN-PLN from beneath the aortic arch to the thoracic entrance. During scavenging, upon encountering the lymph node fragments, the broken lymph nodes will be individually bagged and submitted for testing as a single lymph node. The average number of dissected lymph nodes through microinvasive esophageal cancer resection was 10.8 pieces to 23 pieces.  In our study, the average number of lymph nodes dissected using the suspension method and the nonsuspension method was 22.6 and 20.8 pieces, respectively. The average number of scavenged PLN of the left RLN was 5.2 and 4.6, respectively, which was satisfactory in quantity. No significant difference in the average number of scavenged lymph nodes was observed between the suspension and nonsuspension methods. The complete lymph node dissection rate of the suspension method was significantly better than that of the nonsuspension method. This finding can be attributed to the fact that in the nonsuspension method, the lymph nodes will often be clipped and pulled by grasp forceps, which will likely cause breaking of the lymph. By contrast, in the suspension method, the suspension of the esophagus pulled the lymph nodes. This method rarely requires the use of grasping forceps to clip the lymph nodes; the grasping forceps were used to pull the tissues to expose the operative field, which is not likely to cause breaking of the lymph, thus ensuring better quality of dissection. The previous characteristics of neck lymph node dissection include esophageal cancer in the breasts period, lymphadenectasis by color Doppler ultrasound detection, and quasi cancer metastasis in frozen pathological examination of intraoperatively dissection right RLN. Because of the improved techniques and methods, we have paid attention to the lymphadenectomy around the left RLN since April 2011. Simultaneously, generally, frozen pathological examination is also performed during operation, and the lymphadenectomy in the neck is also performed if cancerometastasis exists. Therefore, the A and B Groups of cervical lymph node scavenging increased 8.0% and 10.0%, respectively, and the transfer rates of cervical lymph node increased 2.7% and 2.9%, respectively. However, it is unclear that whether additional frozen pathological examination around of left RLN during operation is a feature of the scavenged lymph nodes in the neck if cancerometastasis exists, and further studies should be performed using increased the number of patients (larger sample sizes). The suspension method was superior to the nonsuspension method in point of left RLN exposure. However, no significant difference was observed in the thoracic operating time between the two groups. The surgery in this area required not only complete lymph node dissection but also protection of the nerve. The chief surgeon in this study had already completed more than 100 cases of thoracoscopic esophageal cancer resection in the lateral prone position, achieving considerable proficiency toward the surgical anatomy of this region. We spent much time in exploring the fine anatomy of the mediastinal tissue structure. Specifically, we spent time freeing and baring the thoracic left RLN, exposing the sympathetic cardiac branch, avoiding injury to the thoracic duct, and reducing breakage of the lymph nodes. The operations were all close to the inferior part of the aortic arch when seeking the left RLN. The anatomy was also checked upward, and the nerve was never cut-off in any of the cases. The nerve injury rate of RLN was reported to be 14.0-45.3%  in open surgery, whereas the rate was 1.5-20% in microinvasive surgery. ,,, The nerve injury rate of RLN in the suspension method was significantly lower than that in the nonsuspension method. In the suspension method, the tension generated by esophageal suspension allows the position of the left RLN to become superficial, thus making the dissection easier and potentially reducing pulling and clipping toward the nerves. We supposed that the clearer the RLN is exposed, the smaller chance of harming the nerves. In addition, when using an electric hook to dissect the nerve, the device should be maintained at a certain distance from the nerve. The power of the hooks should also be noted, with the maximum power not exceeding 40 W. Esophageal branches should be cut with scissors when encountered during RLN analyzed anatomy check. During dissection, local-small-vessel hemorrhage could be stopped with small dry gauze.
| > Conclusions|| |
The thoracoscopic esophageal suspension method in semi-prone position could complete scavenging toward the left RLN-PLN well. Compared with the nonsuspension method, the thoracoscopic esophageal suspension method has several advantages, such as easier exposure and dissection of the left RLN, higher exposure rate of the sympathetic cardiac branch, lower broken rate of the scavenged lymph nodes, and lower hoarseness rate.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]