Esophagectomy with radical lymphadenectomy still plays the most important role in the multimodality treatment for locally advanced esophageal carcinoma. In recent years, complete 2FL- or 3FL-LN dissection along the esophagus, especially along the bilateral RLNs has been emphasized in the surgical treatment for ESCC. It can not only increase the accuracy of pathological staging, but also improve the prognosis for the patients with thoracic ESCC . However, extensive LN dissection also increase the risk of RLNP and the incidence of associated complications, such as aspiration, respiratory complication, anastomotic leakage, et al. Permanent RLNP also compromises patients’ life quality. As reported in the literatures, the incidence of RLNP after esophagectomy ranged from 10.0–58.9% [4–9]. These disparities may be attributed to variation in the extent of lymph node dissection, usage of surgical technique, the T-stage of the primary tumor, and number of metastatic lymph nodes, and surgeons’ experience [10–11]. Patients with RLNP may present with symptoms from hoarseness, dyspnea during speech, aspiration, difficulty with coughing and expectation of sputum, and may even suffocate in case of bilateral damage. Consequently, dysfunction of RLNs may result in other post-operative complications such as pneumonia, anastomotic leakage, which prolong hospital-stay and severely compromised the post-operative life quality of the patients with esophageal cancer [12–13]. Our study demonstrated that extensive lymph nodes dissection along recurrent laryngeal nerves increased the risk of RLN injury, and subsequently resulted in high incidence of pneumonia and anastomotic leakage, this is consistent with what reported in the literature [12–13]. The patients with temporary or permanent RLNP after esophagectomy usually have difficulties with swallowing and coughing, suffer from the associated pulmonary complications, they can’t recover smoothly and need much longer treatment and hospital stay. Their life quality was deteriorated and medical cost significantly increased. These results stress the importance of preserving the RLN for both short- and long-term outcomes.
The incidence of RLNP after esophagectomy with radical 2FL or 3FL LN dissection was 11.5% in this series, which is similar to the results of previous studies [4–9], Our diagnosis of RLNP mainly based on the symptoms such as hoarseness, aspiration, difficulty with coughing except a few by bronchoscopy or esophagoscopy. And most RLNPs were temporary, and most of them recovered within 6 months, indicating that injury of the RLNs might be caused by compression or stretching or compromised blood supply of the nerves other than structure damage. In this study, univariate analysis showed that patients with extensive 3FL lymph node dissection had a higher RLNP rate than that those with 2FL (24.0% vs 8.0%, P༜0.001) and the incidence of RLNP increased as the number of metastatic LNs along RLN increased. This suggested that more extensive LN dissection could lead to higher RLNP rate and neoadjuvant therapy was needed for patients with suspicious RLN LNs metastasis.
Pulmonary complication was reported to be the most common postoperative complication after esophagectomy [14–15]. Our study showed that RLNP was an independent risk factor for postoperative pulmonary complication. In our study, 8 patients were transferred to ICU due to respiratory failure, 7 of the 8 patients were reintubated, 1 patient had tracheotomy eventually. And 2 of them died within 30 days postoperatively, both of them experienced RLNP. Patients with RLNP could not close the glottis completely, which resulted in pulmonary infection leading to weak coughing, ineffective expectoration aspiration and retention of secretion, which finally result in pulmonary infection even respiratory failure . These results stress the importance of preserving the RLN to decrease the incidence of postoperative pulmonary complications.
Anastomotic leakage is also a common and serious complication after esophagectomy. which does not prolong hospital stay and treatment, but also increase medical expense significantly. [17–19]. Our results showed that the incidence of anastomotic leakage was significantly correlated with RLNP (17.9% vs 7.0%, P=0.029). This may be due to the inability of coughing in patients with RLNP, which lead to the rising of pressure in the thoracic cavity and was transmitted to the anastomosis site when patient tried to cough and expect the sputum hardly . Another possible reason may be poor nutritional status caused by difficulty in swallowing, which affects tissue healing .
Considering harmful consequences of RLNP, it is impressive to prevent RLNP during esophagectomy. It was reported in literatures that noninvasive intraoperative neurological monitoring (IONM) is safe and feasible, which can help avoid intraoperative RLN injury and reduce the incidence of RLNP . IONM has been a routine application during thyroid surgery to avoid RLN injury, and its positive effects have been proven . Therefore, IONM may enable surgeons to identify and preserve the RLN during lymph nodes dissection near bilateral RLN. The usage of energy instruments such as electric knife, electric hook, and ultrasonic knife brings great convenience to the operation, which can significantly reduce surgical hemostasis and operation time . However, thermal injury during the use of energy instruments is a substantial reason of RLNP. Therefore, direct contact with the RLN should be avoided and a safe distance of more than 3mm should be maintained when using energy instruments . And it has been proven that the use of non-energy devices such as scissors and hemostatic clips can reduce the incidence of RLNP [24–26].
One limitation of this study is that this is a retrospective study and all patients included were from a single center and operated by a group of surgeons with difference in surgical skills and experience. Another limitation is that diagnosis of RLNP were mainly based on clinical symptoms instead of laryngoscopy.
RLNP after esophagectomy is significantly associated with an increased incidence of pulmonary complication, anastomotic leakage and much longer hospital stay. It is impressive that renovation and usage of new technologies are needed to reduce RLNP.