Introduction
Hiatal hernia (HH) is a condition that involves herniation of abdominal contents into the mediastinum via the diaphragmatic hiatus and is characterized by a dilated esophageal hiatus [
1]. HH is considered a major cause of gastroesophageal reflux disease (GERD), which may also be related to abnormal lower esophageal sphincter pressure [
2]. Therefore, many patients with HH have GERD. Patients with GERD who do not respond to proton pump inhibitors (PPIs) may undergo laparoscopic HH repair with anti-reflux surgery [
3,
4], which aims to reconstruct the local anatomical structures and address functional deficiencies at the esophagogastric junction [
5]. The current primary treatment for HH with GERD involves the use of the traditional bilateral surgical approach (TBSA) to perform laparoscopic HH repair and Nissen fundoplication [
6]. While this procedure can provide local protection of the vagus nerve, the integrity of the entire vagus nerve cannot be evaluated. Furthermore, the vagus nerve trunk and its branches are located in the lesser omentum, which must be incised during the TBSA. Although the vagus nerve trunk can be easily protected, small vagus nerve branches within the lesser omentum are usually not visible, thus leading to inadvertent injury during incision of the lesser omentum. These injuries can affect the patient’s reflux symptoms and quality of life [
7,
8].
Therefore, we developed a new surgical approach that we called the “total left-side surgical approach” (TLSA) for laparoscopic HH repair with fundoplication. The potential advantages of the TLSA are that it is technically simple and preserves the lesser omentum and the hepatogastric ligament to a great extent based on the anatomical characteristics of the vagus nerve. This technique may also help improve the postoperative quality of life of patients with HH and GERD. This report describes our findings regarding the anatomical characteristics of the vagus nerve from a cadaver study, which we used to develop the TLSA. Further, we describe the detailed surgical procedure and discuss the preliminary results regarding the safety and short-term effectiveness of the TLSA in five patients who underwent surgical treatment for HH and GERD.
Discussion
The Society of American Gastrointestinal and Endoscopic Surgeons issued guidelines for the management of HH in 2013 [
10]; however, these guidelines did not provide detailed techniques for HH repair or discuss how to avoid nerve damage and protect organ functions during surgery. Moreover, cadaver studies and clinical trials on the treatment of functional diseases, such as HH and GERD, are still lacking [
11,
12].
With the deepening of scholars’ understanding of HH, clinicians are paying more attention to improvements in postoperative quality of life of patients while pursuing curative effects, of which protection of the vagus nerve is particularly important. Studies have established that the hepatic branch of the vagus nerve regulates the movement of the liver and biliary tract [
13,
14]. When the nerve is damaged, it leads to decreased gallbladder peristalsis, limited bile secretion, and gastrointestinal hormone secretion imbalance, which increases the incidence of gallstones and necrotizing cholecystitis [
15,
16]. In severe cases, surgical intervention is required. Therefore, to reduce the incidence of gallstones, the hepatic branch of the vagus nerve needs to be effectively protected during surgery. In addition, the terminal branches of the vagus nerve control the peristaltic movements of the pylorus and duodenum, prevent the occurrence of gastric emptying disorders, reduce the secretion of gastric acid, and control gastric reflux to a certain extent [
7,
17]. Therefore, when operating patients with functional disorders, injury to the vagus nerve is related not only to the expertise and skill of the surgeon but also to factors such as surgical approach, number of operations required, and anatomical variations of the vagus nerve. In our study, we have explained the anatomy of the vagus nerve in detail and have provided a reference for nerve protection in the treatment of functional disorders.
Advancements in laparoscopic tools and techniques and the associated advantages (less trauma, rapid recovery, and operative flexibility) have led to an increased use of minimally invasive techniques for treating HH. As a result, the primary treatment of HH now involves laparoscopic repair with fundoplication via the TBSA [
18,
19]. The vagus nerve can be locally protected during procedures performed using the TBSA; however, the integrity of the entire vagus nerve cannot be evaluated. Thus, some cases involve unidentifiable injury to the hepatobiliary branch of the vagus nerve, which only becomes apparent after the patient experiences postoperative complications, such as bile secretion disorders and gastrointestinal dysfunction, that seriously affect their quality of life [
5,
7,
14,
17].
Here, we performed a cadaver study to evaluate the anatomical characteristics of the vagus nerve and used the results to develop the TLSA, which is currently being tested in a clinical trial involving patients with HH and GERD. Through the present study, we found that the TLSA can theoretically preserve the physiological function of the vagus nerve and the organs it innervates, which is supported by the fact that none of our five patients experienced any postoperative adverse effects or complications. Moreover, compared with the TBSA, the TLSA permits full dissociation of the gastrosplenic ligament at the stomach’s greater curvature, which allows the surgeon to stretch the stomach to the right and, thus, obtain a broader surgical field. The increased working area may permit better outcomes in terms of laparoscopic hiatus reconstruction, mesh placement, suturing, and fixation, especially in bariatric and morbidly obese patients. Finally, the TLSA may also help shorten the operation time, reduce surgical trauma, and improve short-term therapeutic effects and postoperative quality of life.
Both TBSA and TLSA can be used in function-preserving procedures, however the TLSA is a modification of the TBSA. The significant difference between the two is that the TLSA can reduce the involvement of the lesser omentum, so that the vagus trunk and its branches that are distributed in the lesser omentum can be protected to the maximum extent possible, thereby decreasing the probability of injury to the vagus nerve.
At present, neurophysiological monitors are widely used in the management of thyroid and orthopedic diseases with good efficacy; however, their use in the treatment of HH is still controversial. In their study involving mice, Berthoud et al. used neurophysiological monitors to discover that the hepatic branch of the vagus nerve is mainly distributed in the distal stomach and the celiac branch is distributed in the duodenum [
20]. Based on the anatomical structure of the vagus nerve in mice, a clinical trial conducted by Korean scholars found that the nerve endings of the hepatic and celiac branches are mainly distributed in the duodenum [
21]. During surgery, electrical stimulation acts on the hepatic and celiac branches of the vagus nerve. By recording the surface electrical activity of the duodenum, the integrity of the vagus nerve can be effectively determined, which suggests that electrophysiological evaluation of nerves has some practical implication in the protection of the vagus nerve around the stomach[
21]. Although we cannot directly evaluate the integrity of the vagus nerve after surgery, we can indirectly evaluate its function based on the improvement in patient’s postoperative clinical symptoms, quality of life, and long-term gallbladder stone incidence, which can confirm the viability of the TLSA. In the future, the neurological function of the vagus nerve can be preserved to a greater extent with the help of neurophysiological monitors.
This study has several strengths. First, it is a prospective study; therefore, the efficacy and safety endpoints to be studied were clearly and completely recorded, guaranteeing high quality and objectivity of the data. Second, the successful treatment and progress of patients in this study will encourage treatment of patients with HH and GERD using a novel approach. Lastly, the TLSA procedure was developed based on the results of the cadaver study, which has laid a theoretical foundation for the implementation of the TLSA.
This study has some limitation. Our findings are limited due to its single-center design, small sample size, and a short follow-up period. In addition, this is an observational study. Although the safety and efficacy of the TLSA can be demonstrated to some extent, the study lacks a comparison with the clinical data of procedures performed using the TBSA. Therefore, a multi-centered prospective trial which we conducted currently that includes long-term follow-up periods and a large sample to compare the outcomes of the TLSA and TBSA to validate our preliminary findings of good safety and efficacy [
9].
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