Imaging of bariatric surgery: normal anatomy and postoperative complications

Hyperirritable stomach as a cause of obstructive symptoms after sleeve gastrectomy: clinical and radiographic findings

PURPOSE

To characterize clinical and radiographic features of a hyperirritable stomach after sleeve gastrectomy.

MATERIALS/METHODS

Radiology reports revealed that 10/76 patients (13%) with obstructive symptoms after sleeve gastrectomy had a hyperirritable stomach.

RESULTS

All 10 patients presented with nausea, vomiting, and/or regurgitation. All 10 had emesis on barium studies in the absence of gastric outlet obstruction, gastroparesis, or small bowel obstruction/ileus. Five had extraintestinal causes of nausea/vomiting. Eight had improvement/resolution of symptoms on medical treatment.

CONCLUSION

In 13% of patients with nausea/vomiting after sleeve gastrectomy, barium studies revealed a hyperirritable stomach, which likely is multifactorial and self-limited in most patients.

A new proposed mechanism of action for gastric bypass surgery: Air hypothesis

Roux-en-Y gastric bypass (RYGB) surgery is one of the most effective treatments for obesity and type II diabetes. RYGB was originally believed to work by mechanically restricting caloric intake or causing macronutrient malabsorption. However, such mechanical effects play no role in the remarkable efficacy of gastric bypass. Instead, mounting evidence shows that altered neuroendocrine signaling is responsible for the weight reducing effects of RYGB. The exact mechanism of this surgical response is still a mystery. Here, we propose that RYGB leads to weight loss primarily by inducing a functional shift in the gut microbiome, manifested by a relative expansion of aerobic bacteria numbers in the colon. We point to compelling evidence that gastric bypass changes the function of the microbiome by disrupting intestinal gas homeostasis, causing excessive transit of swallowed air (oxygen) into the colon.

Early postoperative imaging after non-bariatric gastric resection: a primer for radiologists

Abstract

Surgical resection represents the mainstay treatment and only potentially curative option for gastric carcinoma, and is increasingly performed laparoscopically. Furthermore, other tumours and selected cases of non-malignant disorders of the stomach may require partial or total gastrectomy. Often performed in elderly patients, gastric resection remains a challenging procedure, with significant morbidity (14–43% complication rate) and non-negligible postoperative mortality (approximately 3%). This paper provides an overview of contemporary surgical techniques for non-bariatric gastric resection, reviews and illustrates the expected postoperative imaging appearances, common and unusual complications after partial and total gastrectomy. Albeit cumbersome or unfeasible in severely ill or uncooperative patients, contrast fluoroscopy remains useful to rapidly check for anastomotic patency and integrity. Currently, emphasis is placed on multidetector CT, which comprehensively visualizes the surgically altered anatomy and consistently detects complications such as anastomotic leaks and fistulas, duodenal stump leakage, afferent loop syndrome, haemorrhages, pancreatic fistulas and porto-mesenteric venous thrombosis. Our aim is to help radiologists become familiar with early postoperative imaging, in order to understand the surgically altered anatomy and to differentiate between expected imaging appearances and abnormal changes heralding iatrogenic complications, thus providing a consistent basis for correct choice between conservative, interventional or surgical treatment.

Teaching points

• Radical gastrectomy is associated with frequent postoperative morbidity and non-negligible mortality.

• In cooperative patients fluoroscopy allows checking for anastomotic patency and leaks.

• Multidetector CT with / without oral contrast comprehensively visualizes the operated abdomen.

• Awareness of surgically altered anatomy and expected postoperative appearances is warranted.

• Main complications include anastomotic and duodenal leaks, haemorrhages and pancreatic fistulas.

Thoracic Imaging After Bariatric Surgery

Obesity and its association with long-term health problems constitutes one of the major challenges in medicine. Though diet regulation and exercise are the primary treatment strategies, surgery is the most reliable long-term solution. Although bariatric surgical complications continue to decline, prompt recognition is essential to optimize patient outcomes. Despite their relative rarity, it is important to recognize thoracic complications, as several of these can result in severe morbidity and mortality. This article describes common bariatric surgical procedures performed, their expected postoperative appearances, and intrathoracic complications.

Gastric and colonic erosion caused by laparoscopic gastric band: a case report

Laparoscopic adjustable gastric banding is commonly used to treat obesity. It rarely results in complications, one of which is gastrointestinal erosion. Simultaneous erosion of the stomach and colon is a rare finding that has been documented in only a few case reports. We present a 62-year-old female with abdominal pain, nausea, and hematochezia. She was found to have simultaneous gastric and colonic erosion identified on CT scan. Imaging findings were confirmed and device was removed during surgery.

Validation of a new method for the endoscopic measurement of post-bariatric gastric outlet using a standard guidewire: an observer agreement study

Background and aims

Between 10 and 20% of all patients undergoing bariatric surgery procedures regain weight secondary to a gastrojejunostomy enlargement. The aim of this study was to validate the interobserver agreement while measuring gastric outlet diameters using a new standard guidewire.

Methods

We selected thirty-five videos of consecutive endoscopic procedures on patients undergoing esophagogastroduodenoscopy after a Roux-en-Y gastric bypass procedure. All videos were evaluated by four raters: two expert endoscopists and two trainees. We excluded videos having a slipped Fobi ring or a strictured gastric outlet. Anastomosis diameter was measured using a novel device with standardized markings on a guidewire (Hydra jagwire, Boston Scientific, Natick. MA) as well as the current gold standard defined as a calibrated endoscopic measuring instrument (Olympus America, Center Valley, PA).

Results

We obtained 272 measurements of the gastric outlet. Overall agreement measured through intra-class correlation coefficients for the gold standard was 0.84 (p < 0.01) and 0.83 (p < 0.01) for the new guidewire. Agreement among experts was 0.699 (p < 0.01), while among trainees it was 0.822 (p < 0.01).

Conclusion

The new guidewire demonstrated a high degree of observer reliability, also presenting similar results between expert endoscopists and trainees.

Gastric infarction following gastric bypass surgery

Gastric infarction is an extremely rare occurrence owing to the stomach's extensive vascular supply. We report an unusual case of gastric infarction following gastric bypass surgery. We describe the imaging findings and discuss possible causes of this condition.

Prediction of excess weight loss after laparoscopic Roux-en-Y gastric bypass: data from an artificial neural network

INTRODUCTION

Laparoscopic Roux-en-Y gastric bypass (LRYGB) has become the gold standard for surgical weight loss. The success of LRYGB may be measured by excess body mass index loss (%EBMIL) over 25 kg/m(2), which is partially determined by multiple patient factors. In this study, artificial neural network (ANN) modeling was used to derive a reasonable estimate of expected postoperative weight loss using only known preoperative patient variables. Additionally, ANN modeling allowed for the discriminant prediction of achievement of benchmark 50% EBMIL at 1 year postoperatively.

METHODS

Six hundred and forty-seven LRYGB included patients were retrospectively reviewed for preoperative factors independently associated with EBMIL at 180 and 365 days postoperatively (EBMIL180 and EBMIL365, respectively). Previously validated factors were selectively analyzed, including age; race; gender; preoperative BMI (BMI0); hemoglobin; and diagnoses of hypertension (HTN), diabetes mellitus (DM), and depression or anxiety disorder. Variables significant upon multivariate analysis (P < .05) were modeled by "traditional" multiple linear regression and an ANN, to predict %EBMIL180 and %EBMIL365.

RESULTS

The mean EBMIL180 and EBMIL365 were 56.4 ± 16.5 % and 73.5 ± 21.5%, corresponding to total body weight losses of 25.7 ± 5.9% and 33.6 ± 8.0%, respectively. Upon multivariate analysis, independent factors associated with EBMIL180 included black race (B = -6.3%, P < .001), BMI0 (B = -1.1%/unit BMI, P < .001), and DM (B = -3.2%, P < .004). For EBMIL365, independently associated factors were female gender (B = 6.4%, P < .001), black race (B = -6.7%, P < .001), BMI0 (B = -1.2%/unit BMI, P < .001), HTN (B = -3.7%, P = .03), and DM (B = -6.0%, P < .001). Pearson r(2) values for the multiple linear regression and ANN models were 0.38 (EBMIL180) and 0.35 (EBMIL365), and 0.42 (EBMIL180) and 0.38 (EBMIL365), respectively. ANN prediction of benchmark 50% EBMIL at 365 days generated an area under the curve of 0.78 ± 0.03 in the training set (n = 518) and 0.83 ± 0.04 (n = 129) in the validation set.

CONCLUSIONS

Available at https://redcap.vanderbilt.edu/surveys/?s=3HCR43AKXR, this or other ANN models may be used to provide an optimized estimate of postoperative EBMIL following LRYGB.

Multidetector CT imaging of bariatric surgical complications: a pictorial review

The prevalence of obesity is increasing, along with the number of bariatric surgical procedures performed to treat obesity. Laparoscopic sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and laparoscopic gastric banding (GB) comprise the vast majority of procedures with SG now the dominant procedure in the USA. Although multidetector computed tomography (MDCT) is not always the examination of choice for a particular suspected complication, many of these patients present with non-specific abdominal symptoms and undergo MDCT evaluation as an initial diagnostic test. This pictorial essay will review and discuss the normal post-surgical bariatric appearance on MDCT, and the appearance of common and uncommon complications associated with the common bariatric procedures on MDCT with correlative imaging. SG complications include leak/abscess, hemorrhage, splenic injury, and portomesenteric thrombosis. RYGB complications include leak/abscess, gastrogastric fistula, small bowel obstruction, internal hernia, and intussusception. Although GB is waning in popularity, radiologists continue to see the legacy of these patients and complications include gastric prolapse, band erosion, and port/tubing mechanical failures. Awareness of the characteristic findings of bariatric complications on MDCT is critical, allowing for earlier recognition and prompt intervention.

Cross-sectional imaging, with surgical correlation, of patients presenting with complications after remote bariatric surgery without bowel obstruction

Both restrictive and malabsorptive types of bariatric surgery may be associated with short- and long-term complications. The lack of small bowel obstruction is not necessarily indicative of a normal study, as a variety of non-obstructed complications exist. These include stenosis at the gastrojejunostomy, leaks, abscesses, hemorrhage, internal hernias, and gastric band erosions. Radiologists should be familiar with these complications for early diagnosis and intervention before symptoms become life threatening. An understanding of the intraoperative appearances of these complications may improve imaging descriptions and add value to radiological consults for surgeons. This review provides surgical correlations to the imaging features of post-bariatric complications without obstruction of the bowel.

Experience of imaging following laparoscopic sleeve gastrectomy

BACKGROUND

We aimed to report our experience with upper gastrointestinal (UGI) contrast studies and computed tomography (CT) swallow studies after laparoscopic sleeve gastrectomy, and comment on the merits of each modality.

METHOD

Retrospective review of all patients undergoing laparoscopic sleeve gastrectomy (LSG) in a New Zealand hospital between 2011 and 2014 was conducted. Over this time period, routine UGI was replaced by CT swallow studies. All medical records and radiology were reviewed and pertinent findings reported.

RESULTS

Seventy-nine patients underwent LSG over this time period and one patient had to be excluded; 48 (61.5%) had a UGI study and 30 patients (38.5%) had CT swallow. There were no leaks in this study and no leaks became clinically significant. Sixteen of 30 patients (53.3%) undergoing CT swallow had significant incidental findings demonstrated on axial imaging that required follow-up.

CONCLUSION

CT swallow can provide the same information as a UGI but has a significant rate of incidental findings. The rate of incidental pathology on CT is higher than that quoted in the general population. In a bariatric population, this may allow early detection and treatment of co-existent pathology.

Revisional bariatric surgery following failed primary laparoscopic sleeve gastrectomy: a systematic review

Revisional bariatric surgery following laparoscopic sleeve gastrectomy (LSG) failure presents a clinical challenge for the bariatric surgeon. Limited evidence exists in selecting the appropriate revisional operation: laparoscopic gastric bypass (LGB), laparoscopic re-sleeve gastrectomy (LRSG), or other surgical intervention (OSI), to address weight regain. We systematically reviewed the literature to assess the efficacy of existing revisional surgery. A comprehensive search of electronic databases (e.g., Medline, Embase, Scopus, Web of Science, and the Cochrane Library) was completed. All randomized controlled trials, non-randomized comparison study, and case series were included. Eleven primary studies (218 patients) were identified and included in the systematic review. Studies were grouped into three main categories: LGB, LRSG, and OSI. Preoperative body mass index (BMI) was 41.9 kg/m(2) (LGB), 38.5 kg/m(2) (LRSG), and 44.4 kg/m(2) (OSI). After conversion to LGB, BMI decreased to 33.7 and 35.7 kg/m(2) at 12 and 24 months of follow-up, respectively. Excess weight loss (EWL) was 60 and 48 % over the same periods. After LRSG, BMI decreased to 30.4 and 35.3 kg/m(2) with corresponding EWL of 68 and 44 %, at 12 and 24 months, respectively. After OSI, BMI decreased to 27.3 kg/m(2) with an EWL of 75 % at 24-month follow-up but could not be analyzed due to incomplete data collection in primary studies. Both LGB and LRSG achieve effective weight loss following failed LSG. The less technically challenging nature of LRSG may be more widely applicable. Further research is required to elicit sustainability in long-term weight loss benefits.

Relationship between gastric pouch and weight loss after laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is considered safe and effective even as conversion procedure after primary bariatric operations. The correlation between gastric pouch volumes and patients weight loss remains unclear.

METHODS

To assess a correlation between the gastric remnant size and the weight loss, we reviewed 49 consecutive barium swallow UGS performed at our institute from August 2012 through May 2014 in LSG patients with symptoms and/or unsatisfactory weight loss. The anteroposterior (AP), laterolateral (LL) and vertical (CC) diameters of the gastric pouch were measured to calculate the volume by the formula of the ellipsoid (AP × LL × CC × 0.5). Patients were divided in two groups: group 1 without gastric pouch (n = 36) and group 2 with gastric pouch (n = 13). Correlation between pouch volume and weight loss data was calculated with t Student's and Fisher tests to compare the percent excess body mass index (BMI) and percent excess body mass loss (EBL) between two groups, and P < 0.05 was considered statistically significant.

RESULTS

The mean percent EBL was 26.54 ± 11.02 and 27.12 ± 12.35 kg/m(2) in groups with and without pouch, respectively. The mean volume of the pouch after LSG was 17.13 ± 21.56 mm(3). Pouch volume, when present, was not significantly correlated to weight loss (P = 0.88 95% CI, CL 19.88-33.20 group 2; CL 22.94-31.30 group 1).

CONCLUSIONS

No statistical correlation was found between the volume of the gastric pouch and weight loss (percent EBL) after LSG in symptomatic or with unsatisfactory weight loss patients.

Utility of barium studies for patients with recurrent weight gain after Roux-en-Y gastric bypass

AIM

To determine the utility of barium studies for detecting abnormalities responsible for recurrent weight gain after gastric bypass surgery.

METHODS

A computerized search identified 42 patients who had undergone barium studies for recurrent weight gain after gastric bypass and 42 controls. The images were reviewed to determine the frequency of staple-line breakdown and measure the length/width of the pouch and gastrojejunal anastomosis. A large pouch exceeded 6 cm in length or 5 cm in width and a wide anastomosis exceeded 2 cm. Records were reviewed for the amount of recurrent weight gain and subsequent weight loss after additional treatment.

RESULTS

Staple-line breakdown was present in 6/42 patients (14%) with recurrent weight gain. When measurements were obtained, 13/35 patients (37%) with recurrent weight gain had a large pouch, three (9%) had a wide anastomosis, and four (11%) had both, whereas 22/42 controls (52%) had a large pouch, one (2%) had a wide anastomosis, and two (5%) had both. Ten patients (24%) with recurrent weight gain underwent staple-line repair (n = 3) or pouch/anastomosis revision (n = 7). These 10 patients had a mean weight loss of 38.1 lbs versus a mean loss of 8.6 lbs in 19 patients managed medically.

CONCLUSION

Only 14% of patients with recurrent weight gain after gastric bypass had staple-line breakdown, whereas 57% had a large pouch, wide anastomosis, or both. Not all patients with abnormal anatomy had recurrent weight gain, but those who did were more likely to benefit from surgical intervention than from medical management.