Oesophageal leiomyomas are the most common benign tumours of the oesophagus. It has been reported that the disease mainly occurs in the middle part of the oesophagus, followed by the lower and upper parts of the oesophagus (4). The tumour grows slowly, and small oesophageal leiomyomas are usually asymptomatic. With the growth of the tumour, patients may present acid regurgitation, chest pain, dysphagia and dyspepsia. With the development of gastroscopy and ultrasonic gastroscopy technology, an increasing number of asymptomatic small oesophageal leiomyomas have been detected and treated (5). However, in symptomatic patients, oesophageal leiomyomas are usually larger, which increases the difficulty in treatment.
At present, surgical treatment is the preferred choice for oesophageal leiomyoma, and enucleation is widely accepted as an adequate treatment (6). However, surgical indications for oesophageal leiomyoma are still controversial. Oesophageal leiomyoma may grow gradually, which may lead to surrounding tissue compression and potential malignant transformation. It is also difficult to differentiate leiomyoma from stromal tumour and leiomyosarcoma before surgery. Therefore, it is suggested that once diagnosed, surgical treatment should be performed regardless of symptoms (7). Codipilly et al summarized the clinical data of 105 patients with submucosal tumours and found that small leiomyomas grew very slowly, with an average growth rate of 0.5 mm every 6 years (8). At the same time, the rate of dysphagia in patients with larger leiomyoma surgery was higher than that in the conservative observation group, indicating that the risk of digestive tract obstruction caused by larger leiomyoma is lower than that caused by scar stenosis after surgery. However, there are some shortcomings in this study, such as a high rate of loss to follow-up and retrospective design. In our study, the average size of the tumour was 4.31 ± 1.96 cm, and the proportion of symptomatic patients was 44.4% (16/36). Therefore, we indicate surgical enucleation for patients with symptomatic or larger oesophageal leiomyomas (larger than 2 cm), while patients with smaller and asymptomatic oesophageal leiomyomas could be observed and then treated when they were obviously enlarged or had the possibility of malignancy.
Surgery consists of enucleation of smaller tumours. Oesophageal resection is advocated for large lesions, circular tumours, or if the tumour is densely adhesive to the mucosa. Compared with traditional thoracotomy, video-assisted thoracoscopic surgery has the advantages of minimal scarring, less pain, better postoperative respiratory function with fewer perioperative respiratory complications, and an enhanced fast recovery. It is generally considered that a right thoracic approach is used for middle and upper oesophageal tumours, and a left thoracic approach is used for lower oesophageal tumours (9). In our study, all patients completed tumour resection through the right thoracic approach, indicating that the right thoracic approach can complete all operations. Traditional double-lumen endotracheal intubation can achieve single-lung collapse to provide enough surgical vision, but due to the complex intubation process, the incidence of intraoperative tube displacement is high, and there are many postoperative respiratory complications. Thoracoscopic surgery in the prone position has been adopted in the majority of minimally invasive surgeries for oesophagus because it is easy to mobilize the oesophagus (10). Single-lumen endotracheal intubation combined with a bronchial blocker under artificial pneumothorax has the following advantages: 1. Single-lumen endotracheal intubation is relatively simple, and a bronchial blocker can provide an effective seal of the bronchus with minimal trauma to achieve single-lung ventilation. 2. Single-lumen endotracheal intubation causes less damage to the airway mucosa and respiratory tract, which can reduce postoperative pharyngeal discomfort or pain. 3. Artificial pneumothorax (8 mmHg) can obtain good lung collapse, cause capillaries to collapse and reduce bleeding, maintain a better surgical field and reduce side injury. In our study, complete tumour enucleation was achieved in patients in the SLET-B group, with a larger average tumour size and no mucosal damage or other complications and a shorter postoperative hospital stay than patients in the DLET group. Thoracoscopic operation in the prone position with artificial pneumothorax with CO2 insufflation may add merits to the conventional decubitus position.
Oesophageal mucosal injury is the most common complication, especially when the tumour is large and close to the oesophageal mucosa. According to the author's experience, the main operation approach should be designed based on the tumour location, such as the 4th or 5th intercostal space for high and middle thoracic oesophageal leiomyomas and the 6th or 7th intercostal space for lower thoracic oesophageal leiomyomas. Blunt dissection should be used to dissect the tumour, and energy instruments should be avoided near the oesophageal mucosa side to prevent intraoperative oesophageal mucosal injury. After the enucleation of the tumour, the mucosal wound should be carefully examined. Air inflation of the oesophagus through endoscopy or a Levin tube should be used to check the dissected area to confirm the integrity of the mucosa. Absorbable sutures should be used to repair the injured oesophageal mucosa. For large mucosal injuries, the mediastinal pleura should be used to cover the injured part after repair, and the levin tube should be reserved. After 7 days of fasting, upper oesophagography should be performed to determine whether the injury had healed.
According to previous research, carbon dioxide artificial pneumothorax under low pressure (< 8 mmHg) has no significant effect on respiration and circulation (11). In our study, we did not observe any respiratory or haemodynamic disorders perioperatively. Another disadvantage is the inability of continuous sucking of the operative field, which may cause difficulty in the haemostatic process and increase the operation time. In our study, however, the operation time was significantly shorter in the SLET-B group. Therefore, we believe that this shortcoming can be overcome through more experience with this surgical technique.
Nevertheless, several limitations in our study are noted. First, as our data were retrospectively collected, patient selection bias may exist even though baseline characteristics were comparable. The SLET-B group has only been applied since 2017, thus, more experience with surgical technique may contribute to a better outcome in this group. In addition, the sample size was small; thus, larger-scale studies, especially multicentre collaboration, are needed.