FLUOROSCOPIC NECESSITY AND APPEARANCE OF THE NISSEN FUNDOPLICATION POST-OPERATIVE By Jessie Krueger, B.A., R.T.(R) A thesis submitted to the School of Radiologic Sciences in collaboration with a research agenda team In partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN RADIOLOGIC SCIENCES (MSRS) WEBER STATE UNIVERSITY Ogden, Utah December 15, 2023 THE WEBER STATE UNIVERSITY GRADUATE SCHOOL SUPERVISORY COMMITTEE APPROVAL of a thesis submitted by Jessie Krueger, B.A., R.T.(R) This thesis has been read by each member of the following supervisory committee and by majority vote found to be satisfactory. ______________________________ Dr. Robert Walker, PhD Chair, School of Radiologic Sciences ______________________________ Dr. Laurie Coburn, EdD Director of MSRS RA ______________________________ Dr. Tanya Nolan, EdD Director of MSRS ______________________________________________________________________ Christopher Steelman, MS Director of MSRS Cardiac Specialist 2 Abstract Background This research aims to evaluate the post-operative success and challenges of the Nissen Fundoplication anti-reflux surgery, propose a clear radiologic definition, and establish a standardized method for the post-operative upper gastrointestinal fluoroscopy examination. Discussion Gastroesophageal reflux affects 44 percent of the US population, and the Nissen Fundoplication is the gold-standard treatment for this condition. While this procedure has a high success rate of 95 percent, potential complications can arise and require radiologic assessment. Standardizing post-Nissen Fundoplication fluoroscopy studies can help identify technical successes and challenges and provide efficient patient care. Imaging findings are essential in identifying post-surgical complications, providing pathophysiology information and a radiologic report for patient management. Conclusion Complications of the Nissen Fundoplication include esophageal perforation, loosening or tight fundal wrap, wrap herniation, recurrent gastroesophageal reflux, and esophageal dysmotility or dysphagia. Establishing a standardized method for the post-operative upper gastrointestinal fluoroscopy examination can aid in successfully identifying complications with this procedure, leading to timely diagnosis and intervention. Radiologists and Radiologist Assistants can accurately and effectively assess the success or complications of the Nissen Fundoplication by understanding the post-operative imaging findings. 3 Introduction Gastroesophageal reflux (GER) is a common condition in the United States, affecting 44 percent of the population1. The presentation of GER includes symptoms such as heartburn, dysphagia, upper abdominal or chest pain, and a globulus sensation in the throat. An upper gastrointestinal (UGI) study is a fluoroscopic examination that can be used to diagnose GER. This real-time imaging test uses an oral contrast agent to assess the anatomy and function of the esophagus, stomach, and duodenum2. During an UGI study, GER is apparent when contrast flows from the stomach back through the esophagogastric (EG) junction into the distal esophagus. Depending on the amount of contrast refluxed, the degree of GER can be mild, moderate, or severe. This information aids in the discovery, diagnosis, and plan of care for the patient. Persistent GER is routinely treated with anti-reflux medications, but if symptoms persist, surgical intervention may be necessary1. The Nissen Fundoplication is the gold-standard for treating GER. It is a minimally invasive laparoscopic procedure designed to restore the function of the lower esophageal sphincter and prevent reflux. During this procedure, the fundus of the stomach is wrapped 360 degrees around the distal esophagus and GE junction1,3–5. The Nissen Fundoplication has a high success rate of 95 percent, but there are potential complications that can arise, such as persistent reflux, wrap herniation, mechanical failure, and esophageal dysmotility6. These issues can be assessed by a post-operative UGI study. Standardizing post-gastrointestinal surgical fluoroscopy studies can help evaluate technical successes and challenges and provide more efficient and effective patient care. Routine postoperative UGI studies can also help identify and address complications promptly, expedite patient discharge, and allow patients to return to normal diets quickly. 4 The necessity of an immediate postoperative UGI study is a debated topic. While some articles argue against it due to the lack of standardized methods for performing and reporting the study, the majority of literature supports the use of an immediate postoperative UGI study. By providing detailed information on what to evaluate during the postoperative UGI study, radiologists and radiologist assistants can have a cohesive understanding of how to perform the study and produce standardized reports. The purpose of this research is to present detailed information on the fluoroscopic appearance of the Nissen Fundoplication's successes and complications, as well as describe the purpose and method for the postoperative UGI study. This retrospective study will review fluoroscopic case studies of the postoperative Nissen Fundoplication to provide case examples of fluoroscopic images and descriptions of post-Nissen Fundoplication successes and challenges. In conclusion, standardizing postoperative UGI studies and providing detailed information on the fluoroscopic appearance of the Nissen Fundoplication can help improve patient care and outcomes. This research aims to contribute to the standardization of postoperative UGI studies by providing a detailed description of the Nissen Fundoplication's successes and complications. 5 Literature Review To identify previous case studies, a search was conducted with online databases, including Weber State University’s Stewart Library’s OneSearch and Google Scholar. Combinations of the terms such as “fluoroscopic study”, “contrast study”, “barium study”, “radiographic”, “upper GI”, “upper gastrointestinal”, “Nissen fundoplication”, “fundoplication”, “post-fundoplication”, “gastroesophageal reflux”, “GERD”, and “anti-reflux procedure” were used to ascertain relevant literature. The search was supplemented with a reference search of key articles in the area of fluoroscopic post-Nissen Fundoplication imaging. Initially, numerous articles were found, but these were narrowed down based on a review of the case study's description of the Nissen Fundoplication, radiologic role, and imaging of successes and complications. To be included, the study had to be a retrospective analysis of successes and complications of the post-Nissen Fundoplication, contain a variable of pro and anti-postoperative fluoroscopic imaging, and upper gastrointestinal imaging. To determine the fluoroscopic necessity and standardized appearance of the successes and complications of the Nissen Fundoplication post-operatively, a literature review was conducted along with the researcher's expertise to develop primary data. A literature review was conducted to identify the relevant primary study. Fluoroscopy is a radiology modality that uses x-rays in real time to visualize the gastrointestinal system. These examinations are a method to diagnose gastroesophageal morphology, function, and post-operative assessment. An upper gastrointestinal series (UGI) is a fluoroscopic study that evaluates the pharynx, esophagus, stomach, and duodenum. It can help identify esophageal disorders, including achalasia, gastroesophageal reflux, hiatal hernia, or lesions. Gastroesophageal reflux (GER) can be surgically treated with a Nissen Fundoplication, 6 the gold standard anti-reflux procedure7–10. It is important to study the Nissen Fundoplication for gastroesophageal reflux via fluoroscopy UGI to evaluate for post-operative successes and challenges. A Radiologist or Radiologist Assistant is responsible for performing an UGI study, identifying post-operative changes, and reporting a diagnosis. It is essential that a standardized examination, imaging, and report is established to diagnose the success or failure of the Nissen Fundoplication most accurately via fluoroscopy. Knowing the radiographic appearance of a proper Nissen Fundoplication versus the challenges post operatively can help Surgeons and Radiologists achieve the patient’s best outcome. Gastroesophageal reflux is a common condition in which gastric fluid flows retrograde through the gastroesophageal (GE) junction and into the esophagus. It can be caused by a decreased lower esophageal sphincter (LES) pressure, a malfunctioning GE junction, or a hiatal hernia. While GER is often treated with proton pump inhibitor medication and diet modifications, surgical intervention is necessary for patients who have recurrent GER while taking medication1,4,10–13. The Nissen Fundoplication is a laparoscopic surgery that involves a 360° manipulation of the stomach fundus around the distal esophagus to create a functional gastroesophageal sphincter aimed at increasing the LES pressure and preventing reflux1–5,7,10– . It has a greater than 90% long-term success rate for reducing gastroesophageal reflux1,7. 12,14–16 The decision to undergo this procedure is often determined by a pre-operative fluoroscopic study known as an upper gastrointestinal series. Patients who have undergone a Nissen Fundoplication benefit from a post-operative UGI examination4–6,9,11,13,14,17,18. Performing a routine early contrast study provides valuable information on post-surgical changes, such as esophageal or gastric perforation, obstruction, wrap herniation, or persistent reflux. By standardizing post- 7 operative contrast studies for all patients undergoing a Nissen Fundoplication, immediate repair can be made2,4,7,13,14. A post-operative UGI study consists of two contrast techniques: a single-contrast study with a water-soluble agent or double-contrast using a high barium suspension and gas. The examination begins with the patient in an upright position with water-soluble contrast to rule-out concerns of esophageal perforation or wrap herniation1,4,7–9,18. The patient is then positioned prone in a right anterior oblique, water-soluble contrast is orally administered to evaluate for extravasation of contrast. Once no leak is identified, the contrast is exchanged for a barium agent, and the UGI study continues. The patient is positioned in an upright left lateral oblique where effervescent gas crystals are swallowed to distend the esophagus, followed by barium to coat the lining of the esophagus and stomach14. Additional upright barium swallows are performed in the anteroposterior projection, as well as in the left lateral with emphasis on the larynx. Fluoroscopic projections in the upright position are for evaluating mucosal relief and esophageal emptying1,8,13,14. The UGI study continues into the prone position to assess esophageal rings, strictures, motility, and herniation14. The patient starts in a left lateral decubitus and is rolled to coat the Fundoplication and stomach with barium. The turning stops when the patient is in a right anterior oblique position where motility assessment swallows are performed. Supine anteroposterior (AP) images are obtained to evaluate for gastroesophageal reflux and wrap herniation3. This is followed by right lateral projections of the Nissen Fundoplication and stomach. Recumbent imaging is concluded after AP shots of gastric emptying into the duodenum. Once more, the patient is upright, and a barium tablet is orally administered to evaluate for esophageal stricture or obstruction from a tight wrap 14. Imaging should include visualization of the distal esophagus, GE junction, Nissen Fundoplication, stomach, and the 8 duodenum16. By creating standardized expectations for Nissen Fundoplication post-operative UGI studies Surgeons, Radiologists, and patients will improve their roles. Radiologists and Radiologist Assistants who perform fluoroscopy examinations should have the ability to accurately identify a successful Nissen Fundoplication and any associated complications. A literature review revealed several common post-operative complications that may be detected through fluoroscopy. These challenges include esophageal or gastric perforation, obstruction, wrap herniation, GER, and wrap tightness. Contrast entering a redundant fold that overlays the cardia of the esophagus is an indicator of loosening of the Fundoplication, while an obstruction or stasis of contrast in the distal esophagus can indicate that the wrap is too tight 1,3,7. Anastomotic edema can also present with a similar stasis appearance, but it is a normal early postoperative occurrence3,4,4,5,7,13,14. If the patient experiences persistent reflux post-Fundoplication, then contrast flowing from the stomach or wrap back up the esophagus through the EG junction can be caused by the wrap either loosening and decreasing LES pressure, herniation, or surgical technical failure. Wrap herniation or migration is another complication that can occur following a Nissen Fundoplication. The wrap is still intact, but it has migrated above the hiatus. There are two types of hernia, the hiatal hernia or the paraoesophageal hernia. A hiatal hernia is visualized as the entire fundoplication and superior stomach move above the diaphragm1,5,7,8,11,14. While a paraesophageal hernia occurs when only the fundus herniates above the diaphragm, leaving the EG junction correctly positioned 1,3,8,9,11. Migration of the Nissen Fundoplication can cause persistent reflux or esophageal obstruction, and early detection can be accomplished through a post-operative UGI that results in immediate reoperation and repair. Esophageal or gastric perforation is a serious complication that requires immediate remediation to prevent infection, which is why a post-operative fluoroscopic 9 examination is essential. Water-soluble contrast is used to assess for a leak and will appear as an uncontained accumulation or stream of contrast extravasation outside of the esophagus or stomach4,5,7,9,18. An anastomotic leak will present in the same way and is equally concerning. It is important to be able to identify these postoperative Nissen Fundoplication challenges efficiently and accurately for the patient’s best interest. The literature review emphasizes the need to create a standardized method of performing, evaluating, and reporting UGI studies post-operatively while stressing the importance of correctly recognizing and imaging both the complications and successes of a Nissen Fundoplication procedure2,4,7,13,14. Providing more research, education, and visualizations will aid in the advancement of the radiologic role in post-operative gastrointestinal procedures. Fluoroscopic examinations provide a complementary assessment of patient symptoms, evaluation, and follow-up care8. This research is important to support improved fluoroscopic techniques and provide superior patient outcomes. 10 Discussion/Conclusion Etiology and Epidemiology: Gastroesophageal reflux (GER) is a prevalent disorder affecting 44 percent of the United States’ population1. Evaluation and analysis of GER epidemiology are carried out by gastroenterologists and abdominal radiologists, who diagnose the condition through an upper gastrointestinal or esophagram examination using radiographic fluoroscopy. GER occurs when stomach acid and contents flow back through the esophagogastric junction (commonly referred to as the lower esophageal sphincter, or LES) into the distal esophagus. Multiple factors can contribute to GER, including loss of LES function, hiatal hernia, delayed esophageal emptying, and decreased lower esophageal pressure. Symptoms associated with gastroesophageal reflux include heart burn or chest pain, dysphagia, a globus sensation, coughing, or sore throat. Recurrent or severe reflux can lead to esophageal diseases such as Barrett’s esophagus, esophagitis, or damage leading to strictures or lesions. While proton pump inhibitors are often used to treat reflux, surgical intervention is recommended for those with recurrent or severe symptoms. The gold standard for anti-reflux procedures is the Nissen Fundoplication (NF), which involves manipulating of the stomach fundus to wrap it 360° around the distal esophagus1– 5,7,10–12,14–16 . This wrap recreates a functional LES, which can improve the esophagogastric junction and increase lower esophageal pressure to prevent reflux. To ensure the creation of the fundoplication wrap is not too tight or loose, the wrap is created with a luminal dilator in place1,16. This aims to reduce the risk of creating a wrap that is too tight which can lead to postoperative challenges. To evaluate post-operative successes and challenges, it is crucial to study the Nissen Fundoplication using a fluoroscopic upper gastrointestinal study (UGI). Radiologists or Radiologist Assistants are responsible for performing the UGI study, identifying post- 11 operative changes, and reporting a diagnosis. It is essential to establish a standardized fluoroscopic examination, imaging, and report to diagnose post-Nissen Fundoplication successes or failures accurately. Understanding the radiographic appearance of a proper Nissen Fundoplication and identifying challenges post-operatively can help surgeons and radiologists achieve the best outcome for their patients. Early versus Routine Post-Nissen Fundoplication Imaging: The UGI fluoroscopic examination is used to assess the entire esophagus, esophagogastric junction, stomach, and first portion of the small bowel. The type of contrast agent used for postoperative fluoroscopic studies depends on the time elapsed since the surgery. A water-soluble contrast agent is used for the initial radiographic evaluation following post-operative patients8,7,11,18. A single contrast, water-soluble agent is recommended for post-operative gastrointestinal studies due to its ability to be rapidly absorbed from the extraluminal space if a leak occurs18. Dempsey, Swanson et al., and Houston, M.D. et al., suggest starting the UGI with a water-soluble contrast and then switching to Barium contrast if no leak is detected. Barium is the preferred contrast agent for evaluating the esophagus, stomach, and intestines because it coats and displays mucosal appearance more effectively. A double contrast study involves using both Barium and effervescent gas crystals to expand the esophagus, stomach, and intestine for better visualization of the gastrointestinal mucosal lining. For routine post-Nissen Fundoplication imaging, a double contrast study should only be performed once the patient has healed completely from the surgery. The effervescent gas crystals used in a double contrast examination could cause increased pressure on the surgical site leading to perforation or pain. Early postNissen Fundoplication UGI study is performed with water-soluble contrast as soon as one day after surgery and continues until a leak or severe complication has been ruled out and before 12 resuming oral feeding7,11,18. Once no post-operative extravasation of contrast is identified, a Barium UGI study can be performed to evaluate for success or complications of the Nissen Fundoplication procedure. This can be completed as a routine examination immediately following the water-soluble clearance or at the surgeon’s discretion, days or weeks after the antireflux procedure. UGI Imaging and Positioning: At present, there is no standardized method for conducting, interpreting, and reporting an UGI study for a post-operative NF. Therefore, one of the aims of this research is to propose a standardized practice that can serve as a cohesive resource for Radiologists and Radiologist Assistants. The proposed method is developed based on a thorough literature review, retrospective case studies, and examination recommendations. To ensure comprehensive evaluation, UGI imaging should encompass visualization of the distal esophagus, gastroesophageal junction, Nissen Fundoplication, stomach, and duodenum. The UGI study preparation consists of the patient fasting for six hours before the examination, obtaining the patient’s medical history, and addressing any contraindications 19. Before fluoroscopic imaging begins, an abdominal scout x-ray needs to be obtained to rule out free air in the extraluminal space (Fig. 1). Initially, a single contrast UGI examination is performed to evaluate for esophageal perforation19. The UGI examination starts with the patient in an upright left posterior oblique position, a water-soluble contrast is orally administered to rule out esophageal perforation or wrap herniation (Fig. 2). The patient is then positioned into a right lateral projection for evaluation of aspiration and post-operative changes to the lyngopharynx (Fig. 3). After that, the patient is moved into a left lateral decubitus position to rule out leakage (Fig. 4). Once no extravasation of contrast is identified, the water-soluble contrast is 13 exchanged for Barium, and the UGI study continues, as suggested by Dempsey, Swanson et al., and Houston, M.D. et al. Next, the patient is repositioned in an upright left posterior oblique position, and Barium is orally administered to coat the lining of the esophagus and stomach (Fig. 2). Additional upright barium swallows are performed in the anteroposterior projection, as well as in the right lateral. Obtain additional images as contrast reaches the distal esophagus and flows through the NF wrap19. Imaging of the GE junction is crucial for post-operative examinations to identify narrowing and other complications. The purpose of fluoroscopic projections in the upright position is to evaluate mucosal relief and esophageal emptying. The UGI study continues into the prone position to assess esophageal strictures, motility, and herniation. The patient starts in a left lateral decubitus position and is rolled to coat the Fundoplication and stomach with barium. The turning stops when the patient is in a right anterior oblique position, where motility assessment swallows are performed (Fig. 5). Barium should pass through the esophagus without breakup of the bolus propelled by the primary peristaltic wave. Additional images can be obtained if there is dysmotility or concerns for wrap herniation. Supine anteroposterior (AP) images are obtained to evaluate for reflux and wrap herniation (Fig. 6). This is followed by right lateral projections of the Nissen Fundoplication and stomach (Fig. 7). An UGI study must also include AP pictures of gastric emptying into the duodenum (Fig. 8). Finally, recumbent imaging is concluded after obtaining a prone abdomen x-ray that shows the distal esophagus, stomach, and first portion of the small bowel19 (Fig. 9). Once more, the patient is positioned upright, and a barium tablet is orally administered to evaluate for esophageal stricture or obstruction from a tight wrap. Once all fluoroscopic imaging has been obtained, the UGI study is complete. 14 The patient should be advised to keep will hydrated throughout the day due to Barium’s tendency to dehydrate and constipate. The images obtained during the examination are evaluated for anatomy, function, reflux, and abnormalities. A standardized method for performing and interpreting an UGI study for a post-Nissen fundoplication can provide consistent and reliable results, aiding in the diagnosis and management of complications related to the surgical repair. The proposed method is relatively simple and can be performed in most radiology departments. However, it is important to note that the interpretation of the images obtained from the study requires experience and expertise in radiology and gastroenterology. The proposed method involves patient preparation, contrast administration, fluoroscopic imaging, and interpretation. This method can help to diagnose and manage complications related to the surgical repair and can improve patient outcomes. Post-Nissen Fundoplication Success: The Nissen Fundoplication is a laparoscopic surgery with a success rate of over 90% for reducing gastroesophageal reflux1,7. A successful NF can be identified on UGI imaging as a 2-4 centimeter pseudomass with smooth borders surrounding the esophagogastric cardia 1,5,7,11,20. A properly positioned wrap should be situated completely below the diaphragm. During contrast imaging, a mildly narrowed distal esophagus should be observed, which is characteristic of the NF wrap1,7. There should be no delayed transit of contrast through the LES and into the stomach while upright, and no retrograde flow of contrast into the distal esophagus during the RAO motility swallows2,7,13. On fluoroscopic imaging, a successful NF will be characterized by a tapering of the distal esophagus with a smooth, round filling defect. The UGI study will show no delayed transit of contrast, a reduction in GER, as well as diminished esophagitis. Patients who 15 undergo successful NF will experience decreased reflux symptoms and be able to resume their routine daily activities. Post-Nissen Fundoplication Complications: Post-operative fluoroscopic imaging is a valuable tool for accurately evaluating surgical changes to the upper gastrointestinal system. Early post-Nissen Fundoplication UGI studies can provide immediate diagnosis of complications, allowing for prompt surgical corrections if necessary. It is important to create an imaging reference for Radiologists and Radiologist Assistants who perform these examinations to ensure prompt identification of post-operative complication and provide proper patient care. According to Carbo, MD, the Nissen Fundoplication has a 2.8 percent rate of patients who require revisional surgeries due to complications discovered from early post-operative fluoroscopic studies. Complications associated with post-Nissen Fundoplication include esophageal perforation, obstruction, wrap migration, persistent GER, and dysphagia. Early postoperative complications of NF include esophageal perforation or obstruction due to edema 14,19. While, late post-operative NF complications consist of recurrent GER or anatomic strictures14,19. It is important to assess patients for these complications, as it can significantly impact recovery or require additional surgical interventions. Perforation: A post-operative perforation is a severe complication of upper gastrointestinal surgery that typically occurs at the anatomic site3,18. Post-Nissen Fundoplication perforation is commonly observed in the lower esophagus or gastric fundus7. Initial evaluation for perforation should use a water-soluble contrast agent because it can be reabsorbed by the body if extravasation occurs 16 into the extraluminal space. Extravasation of contrast through an esophageal perforation can be visually identified as a relatively contained mediastinal collection of contrast 7 (Fig. 10). A leak can be caused by the formation of an abscess from surgical scarring, which is identified as a pocket with air-fluid levels at the level of the fundoplication3,5. Perforation can also be characterized as free extravasation of contrast into the extraluminal space, appearing as thin lines of contrast without smooth boarders, outside the contained walls of an abscess or the esophagus. In creating a standardized method for post-Nissen Fundoplication UGI studies, it is recommended that if leakage is identified, then the exam is complete. If no leak is identified, then Barium contrast should be used for the remainder of the examination. It is important to obtain additional imaging of the leak including upright, supine, and oblique views7,19. Patients with perforation can be asymptomatic, emphasizing the importance of early post-operative fluoroscopic evaluation. Tight/Loose Wrap: As previously discussed, moderate edema of the lower esophagus is expected and considered normal for early post-operative Nissen Fundoplication. However, this becomes a concern when narrowing of the LES is severe and causes delayed esophageal emptying or obstruction. These complications are caused by a wrap that is too tight around the LES, leading to functional failure of the NF. Symptoms may include dysphagia, persistent GER, and abdominal bloating1. Differentiating between esophageal stricture and a too-tight wrap can be accomplished by observing the recurrence of delayed contrast transit through the LES into the stomach14. Fluoroscopic assessment of esophageal emptying should be evaluated in the upright position. A tight wrap is characterized by contrast filling the distal esophagus with a smooth narrowing, along with dilation of the proximal lumen, and delayed passage of contrast through 17 the LES and wrap1 (Fig. 11). Another distinction for a tight wrap is a filling defect or indentation of the distal esophagus just superior the wrap7,8. In standardizing the post-Nissen Fundoplication method for UGI studies, the examination should conclude with the patient swallowing a 13millimeter Barium tablet. If the tablet is retained within the esophagus and does not pass through the EG junction or NF wrap, then a stricture or too-tight wrap is indicated. If an UGI study demonstrates a NF wrap that is too tight, then the surgeon can make corrections either by esophageal dilation or surgical revision1. Complications of a NF can also include a wrap that is too loose, which can lead to recurrent GER. This is caused by an inadequate constriction of the LES, leading to functional failure of the NF. An UGI study diagnoses a loose wrap when there is spontaneous GER with the wrap still intact and situated below the diaphragm1 . Imaging will show antegrade flow of contrast from the fundus and wrap into the distal esophagus (Fig. 12). Loosening also presents when contrast enters the redundant space within the folds of fundoplication wrap3 (Fig. 13). The severity of the loosening is determined by the amount of contrast that enters the wrap. There can also be a complete breakdown of the NF wrap, characterized by the pseudotumor no longer being visualized3 (Fig. 14). If an UGI study diagnoses a loose wrap, the surgeon can correct it by dilating the EG junction. Whereas, if there is a complete breakdown of the NF wrap, then surgical intervention is necessary to correct the procedure. Wrap Herniation: A potential post-operative complication of a Nissen Fundoplication is wrap herniation. According to Zarzour et al., there is an approximate 2.7 percent re-operation rate of a NF due to post-operative wrap herniation. This is when the NF wrap, or a portion of the stomach migrates above the diaphragm into the thoracic cavity. There are three variations of herniation that can 18 occur, including hiatal hernia, paraesophageal hernia, and herniation of abdominal contents through the diaphragm3. The type of herniation can be determined during a post-Nissen Fundoplication UGI examination. Visualizing the EG junction is crucial in differentiating between the three types of hernia. A hiatal hernia occurs when the entirety of the NF wrap and the upper portion of the stomach migrate through the esophageal hiatus3. The wrap can maintain its shape and function when it has herniated, but recurrent GER can present due to the loss of intraabdominal pressure3. A hiatal hernia can be determined if the EG junction and the wrap are located above the diaphragm (Fig. 15). This type of hernia is commonly referred to as a Hinder type I failure. During an UGI study, contrast highlights the passage of Barium through a hourglass-shaped transition from the distal esophagus into the herniated NF wrap20. A pronounced hiatal hernia can be visualized while the patient is in the upright position, but the EG junction and smaller hiatal hernias can be better identified in the prone right anterior oblique position. Paraoesophageal hernia occurs when only a portion of the stomach fundus migrates through the hiatus3. An UGI examination is necessary for localization of the EG junction. With a paraoesophageal hernia, the LES is correctly situated with the EG junction at the diaphragm, and only the stomach has migrated into the thoracic cavity (Fig. 16). This type of hernia usually involves the left posterolateral portion of the wrap where there are no sutures 3. A paraoesophageal hernia can typically be differentiated in the prone right anterior oblique position, but additional views may be necessary to confirm the location of the EG junction. Post-operative changes can cause an enlarged esophageal hiatus can lead to other abdominal contents migrating through the diaphragm into the thoracic cavity. A slipped NF wrap, or Hinder type II failure can also occur post-operatively (Fig. 17). This occurs when the 19 stomach herniates through the hiatus, while the NF wrap remains situated below the diaphragm1,7. If a hernia is observed during an UGI study, the EG junction needs to be localized in order to differentiate the type of hernia. Recurrent Gastroesophageal Reflux: The Nissen fundoplication is a highly effective surgical treatment for GER, but some patients may still experience post-operative reflux. According to a systematic review of postNissen Fundoplication complications, the overall incidence of post-operative reflux is 6.3 percent. This may suggest a technical failure of the NF procedure, such as wrap herniation or loosening3. An UGI study can be performed to identify GER, during which contrast is pushed out of the stomach, through the LES, and back into the distal esophagus. Reflux is best observed with the patient lying supine after esophageal clearance of contrast (Fig. 18). Provocative maneuvers, such as Valsalva exercise, can be used to entice GER by creating intraabdominal tension through abdominal muscle flexion. The severity of reflux can be determined by the amount of contrast and the distance it travels up the esophagus, categorized as mild, moderate, or severe. The management of post-operative reflux after NF depends on the severity and frequency of symptoms. Mild symptoms may be managed with lifestyle modifications and medications such as proton pump inhibitors. However, in cases of severe or persistent reflux, additional surgical procedures may be required. Dysphagia and Esophageal Dysmotility: Dysphagia is a common complication following a Nissen Fundoplication procedure, affecting up to 63 percent of patients. The etiology of dysphagia post-Nissen Fundoplication can 20 be attributed to anatomical changes from surgery, such as wrap tightness, edema, or esophageal dysmotility. While it is expected to have post-surgical esophageal edema at the LES, leading to dysphagia or dysmotility, it typically resolves within 10 days after the procedure 5. If longer episodes persist, it should be evaluated to identify any post-operative complications. Radiographic studies, such as an UGI study, can help identify any anatomical abnormalities that may be contributing to the dysphagia or dysmotility. During the motility assessment test of an UGI study, the patient is positioned in a prone right anterior oblique. A single bolus of contrast is swallowed, and adequate esophageal clearance with the primary peristaltic wave is evaluated (Fig. 19). A proper swallow should show no ballooning of the distal esophagus or retrograde flow of contrast 7. Dysmotility, on the other hand, can appear as a breakup of the contrast bolus during the primary peristaltic wave, sending a portion of the contrast retrograde and the other antegrade with tertiary contractions (Fig. 20). Contrast stasis with delayed esophageal emptying can also indicate dysmotility. The management of dysphagia following Nissen fundoplication is primarily focuses on addressing the underlying cause. If dysphagia is due to anatomical changes resulting from the surgery, a revision surgery may be necessary to adjust the wrap. In cases where dysphagia is due to esophageal motility disorders, medication or other treatments may be necessary to improve esophageal function. Swallowing therapy can also be helpful in improving swallowing function and reducing dysphagia symptoms. 21 Discussion Standardizing Post-Nissen Fundoplication UGI Studies Nissen fundoplication is a surgical procedure commonly performed to treat gastroesophageal reflux. The procedure involves wrapping the fundus of the stomach around the lower esophageal sphincter to prevent reflux of gastric contents into the esophagus. An upper gastrointestinal (UGI) study is a fluoroscopic examination often performed after a Nissen fundoplication to evaluate the anatomy and function of the surgical repair. However, currently, there is no standardized method for performing and interpreting this study. This paper aims to propose a standardized method for performing and interpreting a UGI study for a post-operative Nissen fundoplication. Patient preparation should begin with fasting for at least six hours before the examination. Any medications that may interfere with the study, such as antacids, should be discontinued prior to the study. A detailed patient history and description of the anti-reflux procedure performed must be obtained before the UGI study starts. According to a systematic review of 20 studies, it is recommended that early post-Nissen Fundoplication imaging occurs on the first post-operative day to ensure timely detection of complications1,7,9,11. To create a standardized method for early post-operative evaluation, the UGI study should start with a watersoluble contrast agent until perforation and leak are ruled out. Once perforation and leak have been ruled out, the contrast agent can be switched to a barium-based contrast agent to better evaluate the surgical repair. 22 To perform an UGI study, a radiopaque contrast agent, such as water-soluble contrast or Barium, is administered orally to the patient. The contrast agent should be given slowly to ensure that it reaches the stomach and does not cause aspiration. The post-Nissen Fundoplication UGI study starts with the patient in an upright right lateral position and a single swallow of water-soluble contrast is recorded and evaluated to assess the laryngopharynx portion of the esophagus for dysphagia or aspiration. If aspiration occurs, the examination is terminated, and the surgeon is notified. On the next swallow, with the patient in an upright left posterior oblique position, a single swallow of contrast is recorded to evaluate the entire esophagus to the EG junction for aspiration, extravasation of contrast, and esophageal emptying. The last upright swallow is to assess and image the EG junction in the upright AP position, evaluating for extravasation of contrast, esophageal emptying, LES edema, and NF complications. Next, the patient is positioned in the prone right anterior oblique position, and a single swallow of water-soluble contrast is recorded to evaluate the esophagus, EG junction, and NF wrap for a final leak check. If a perforation is identified, the examination is complete, and additional images are necessary, including AP, lateral, and the oblique view that gives the most detail. If no leak is identified, then the water-soluble contrast is switched for barium, and the study is repeated. An UGI study using barium provides enhanced visualization of the gastrointestinal mucosal lining. The study begins with upright images taken in the left posterior oblique position, evaluating the mucosal lining of the esophagus, esophageal emptying, and any hiatal hernia complications. An upright AP recording of the EG junction is obtained with barium to visualize mucosal detail, esophageal emptying, and any complications related to the NF. This is followed 23 by an upright right lateral projection of the laryngeal portion of the esophagus to further evaluate dysphagia and aspiration. The patient is then positioned on their left side for imaging of the EG junction, NF wrap, and stomach in the left lateral position. The patient is log rolled to coat the fundoplication and stomach with barium, stopping when in a right anterior oblique position for motility assessment swallows. The Radiologist or Radiologist Assistant records and observes the transit of the barium through the esophagus, EG junction, NF wrap, and into the stomach after a single bolus is swallowed. Adequate esophageal clearance is indicated by the swift passage of the barium bolus into the stomach with the primary peristaltic wave, with no ballooning of the distal esophagus or retrograde flow of contrast. Dysmotility can appear as a breakup of the primary peristaltic wave or contrast stasis with delayed esophageal emptying. This motility test is performed three times to accurately assess esophageal motility. A final swallow is obtained in the right anterior oblique position to evaluate for herniation. A Valsalva maneuver is performed when the contrast column is passing through the distal esophagus and LES to visualize herniation better. The patient is then positioned in the right lateral position for imaging of the distal esophagus, EG junction, NF wrap, and stomach. The patient rolls onto their back in the supine position to evaluate GER. The fundus fills with barium while in the right lateral position, and the abdominal tension during the roll onto the back can lead to spontaneous reflux. Imaging of the distal esophagus, EG junction, NF wrap, and stomach is obtained while still in the supine position. Recumbent imaging is concluded after obtaining AP images of gastric emptying into the duodenum. Lastly, the patient is repositioned upright, and a barium tablet is orally administered to evaluate for esophageal stricture or 24 obstruction from a tight wrap14. UGI examination imaging should include visualization of the distal esophagus, EG junction, Nissen Fundoplication, stomach, and the duodenum16. A standardized method for performing and interpreting an UGI fluoroscopic study for a post-operative Nissen fundoplication can provide valuable information regarding the anatomy and function of the surgical repair. The proposed method involves patient preparation, contrast administration, fluoroscopic imaging, and interpretation. By creating a standardized method, it promotes consistent and reliable results, which can aid in the diagnosis and management of complications. The proposed method is relatively simple and can be performed in most radiology departments. 25 Conclusion Medical imaging plays a vital role in the diagnosis and treatment of various conditions and diseases. However, interpretating of images can be challenging task due to the subjective nature of the interpretation. Therefore, it is essential to have standardized methods for performing and analyzing radiographic imaging to ensure accurate and reliable diagnoses. According to Levine et al., the Society of Abdominal Radiology recognizes the importance of fluoroscopic examinations in evaluating GER. Dempsey emphasizes that the results of a Barium study complement an EGD and other endoscopic examinations, and are crucial for patient care management. Performing a routine post-operative UGI study is a quality control measure for patients undergoing surgery, as the noninvasive nature of fluoroscopic imaging makes it an essential tool8,9. Fluoroscopic imaging is helpful in assessing post-surgical anatomy, identifying and reporting anatomic and physiologic challenges, and providing valuable information for the surgeon1. Zarzour et al. also agrees that radiographic imaging after anti-reflux surgery is important in assessing and managing patient care. By providing a standard for performing and identifying the successes and failures of a postoperative NF, Radiologists and Radiologist Assistants can better recognize the radiographic appearance of these complications, providing prompt treatment and improved patient outcomes5. 26 Imaging of Successful Nissen Fundoplication Post-Nissen Fundoplication: Fig. 1 Upright AP Scout image for evaluation of abdominal free-air and surgical changes. Fig. 2 Upright LPO fluoroscopic UGI imaging with Barium showing proper dilation of the esophagus, mucosal lining, and motility of contrast. 27 Fig. 3 Upright Right Lateral fluoroscopic UGI imaging with single contrast showing proper motility of contrast without evidence of aspiration. Fig. 4 Recumbent left lateral fluoroscopic spot image of the distal esophagus, Nissen Fundoplication wrap, stomach, and duodenum. 28 Fig. 5 Right Anterior Oblique fluoroscopic spot image of the distal esophagus, Nissen Fundoplication wrap, stomach, and duodenum. Fig. 6 Supine fluoroscopic spot image of the distal esophagus, Nissen Fundoplication wrap, stomach, and duodenum. 29 Fig. 7 Recumbent right lateral fluoroscopic spot image of the distal esophagus, Nissen Fundoplication wrap, stomach, and duodenum. Fig. 8 Prone fluoroscopic spot image of the distal esophagus, Nissen Fundoplication wrap, stomach, and duodenum. 30 Fig. 9 Post-UGI abdomen x-ray image to include distal esophagus, Nissen wrap, stomach, and duodenum. 31 Imaging of Nissen Fundoplication Complications Perforation: Fig. 10 Upright AP fluoroscopic imaging of post-Nissen Fundoplication extraluminal contrast collection, adjacent to the wrap7. Tight Nissen Fundoplication Wrap: Fig. 11 Upright AP imaging of post-Nissen Fundoplication reveals a distal esophageal narrowing due to a Nissen wrap being too tight or “bird-beaking”. 32 Loose Nissen Fundoplication Wrap: Fig. 12 Upright Left Posterior Oblique Post-Nissen Fundoplication fluoroscopic imaging of a complete breakdown of the wrap with reflux. Fig. 13 Supine fluoroscopic imaging of a post-Nissen Fundoplication with a partial breakdown of the wrap. Image A) reveals the partial wrap breakdown with an associated hiatal hernia, and Image B) reveals the partial wrap breakdown with reflux1. 33 Fig 14 Prone Left Anterior Oblique fluoroscopic imaging of a post-Nissen Fundoplication revealing a complete breakdown of the wrap. Nissen Fundoplication Wrap Herniation: Fig 15 Prone Right Anterior Oblique post-operative fluoroscopic imaging revealing a hiatal hernia with an intact Nissen Fundoplication below the diaphragm. 34 Fig 16 Recumbent Right lateral fluoroscopic imaging of a post-Nissen Fundoplication with a paraesophageal hernia and an intact wrap below the diaphragm. Fig 17 Post-Nissen Fundoplication UGI study revealing an intact wrap herniated above the diaphragm. The white arrow show the NF wrap while the black arrows show the distal esophagus1. 35 Recurrent Gastroesophageal Reflux: Fig 18 Anteroposterior fluoroscopic imaging of a post-Nissen Fundoplication revealing reflux into the distal esophagus. Dysphagia and Dysmotility: Fig 19 Gastroesophageal dysphagia with stasis of contrast within the esophagus on a post-operative UGI study on a patient with a Nissen Fundoplication. 36 Fig 20 Esophageal dysmotility during an UGI study on a post-Nissen Fundoplication patient, revealing tertiary contractions and contrast stasis. 37 References 1. Carbo AI, Kim RH, Gates T, D’Agostino HR. Imaging Findings of Successful and Failed Fundoplication. RadioGraphics. 2014;34(7):1873-1884. doi:10.1148/rg.347130104 2. Gan SW, Lee N, Tan SE, Edwards SM, Kiroff GK, Myers JC. Quantification of fluoroscopic fundoplication anatomy: inter- and intraobserver reliability. Diseases of the Esophagus. 2022;35(2):doab045. doi:10.1093/dote/doab045 3. Trinh T, Benson J. Fluoroscopic diagnosis of complications after Nissen antireflux fundoplication in children. : American Journal of Roentgenology : Vol. 169, No. 4 (AJR). Published 1997. 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