A novel dedicated endoscopic stent for staple-line leaks after laparoscopic sleeve gastrectomy: a case series

Efficacy of LigaSure Versus Harmonic Devices in Laparoscopic Sleeve Gastrectomy: A Systematic Review and Meta-Analysis

Our goal is to conduct a thorough systematic review and meta-analysis of comparative studies to evaluate the efficacy of LigaSure (Valleylab, Boulder, CO) compared with Harmonic (Ethicon Endo-Surgery, Inc., Cincinnati, OH) devices in patients undergoing laparoscopic sleeve gastrectomy (LSG). Our search strategy, from inception until March 1, 2024, involved multiple databases, including the Cochrane Controlled Register of Trials (CENTRAL), Web of Science (WOS), PubMed, Scopus, and Google Scholar. We evaluated randomized clinical trials using the Cochrane Risk of Bias tool for randomized trials (RoB-2) tool and non-randomized studies using the Risk of Bias In Non-randomized Studies for Interventions (ROBINS-I) tool. The primary outcomes assessed were operative time, mean length of hospital stay, and the rates of intraoperative complications such as bleeding, organ injury, leakage, and hematoma formation. Additionally, we collected data on postoperative complications, including bleeding, abscess formation, leakage, fever (>38°C), and reoperation rates. Data were analyzed using random-effects models and reported as mean difference (MD) or risk ratio (RR) with a 95% confidence interval (CI) using Review Manager software (RevMan, version 5.4 for Windows, The Cochrane Collaboration, 2020). Four studies, comprising two randomized clinical trials (RCTs) and two retrospective cohort studies, involving a total of 692 patients, were included in the analysis. Both the operative time and length of hospital stay did not significantly differ between the LigaSure and Harmonic groups (p>0.05). The pooled analysis also revealed no significant difference between the LigaSure and Harmonic groups in terms of intraoperative and postoperative complications (p>0.05). In conclusion, our systematic review and meta-analysis found no significant statistical or clinical differences between LigaSure and Harmonic devices in terms of operative outcomes and complication rates in patients undergoing LSG.

Endoscopic Management of Post-Sleeve Gastrectomy Complications

Obesity is associated with several chronic conditions including diabetes, cardiovascular disease, and metabolic dysfunction-associated steatotic liver disease and malignancy. Bariatric surgery, most commonly Roux-en-Y gastric bypass and sleeve gastrectomy, is an effective treatment modality for obesity and can improve associated comorbidities. Over the last 20 years, there has been an increase in the rate of bariatric surgeries associated with the growing obesity epidemic. Sleeve gastrectomy is the most widely performed bariatric surgery currently, and while it serves as a durable option for some patients, it is important to note that several complications, including sleeve leak, stenosis, chronic fistula, gastrointestinal hemorrhage, and gastroesophageal reflux disease, may occur. Endoscopic methods to manage post-sleeve gastrectomy complications are often considered due to the risks associated with a reoperation, and endoscopy plays a significant role in the diagnosis and management of post-sleeve gastrectomy complications. We perform a detailed review of the current endoscopic management of post-sleeve gastrectomy complications.

Long-term follow-up of a cohort with post sleeve gastrectomy leaks: results of endoscopic treatment and salvage surgery

INTRODUCTION

Laparoscopic sleeve gastrectomy (LSG) is the most performed bariatric procedure worldwide. The most challenging postoperative complication is gastric leak. The objectives of this study are to examine the efficacy and morbidity of different therapeutic strategies addressing leakage, and the long-term outcomes of a cohort of LSG leaks.

METHODS

A retrospective review of patients treated for LSG leaks between September 2014 and January 2023 at our high-volume bariatric surgery center was performed.

RESULTS

The charts of 37 patients (29 women and 8 men) were reviewed, with a mean age of 43 years and a median follow-up of 24 months. The mean preoperative body mass index was 45.1 kg/m2. Overall, 30/37 (81%) patients were successfully treated with endoscopic management, and 7/37 (19%) ultimately underwent salvage surgery. If the leak was diagnosed earlier than 6 weeks, endoscopic treatment had a 97% success rate. The median number of endoscopic procedures was 2 per patient, and included internal pigtails, stents, septoplasty, endoluminal vacuum therapy and over-the-scope clips. Complications included stent-related ulcers (10), esophageal stenosis requiring endoscopic dilatations (4), stent migrations (2) and kinking requiring repositioning (1), and internal pigtail migration (3). Revisional surgery consisted of proximal gastrectomy and Roux-en-Y esophago-jejunal anastomosis, Roux-en-Y fistulo-jejunostomy or classic Roux-en-Y gastric bypass proximal to the gastric stricture. In 62% of the cases, the axis/caliber of the LSG was abnormal. Beyond 4 attempts, endoscopy was unsuccessful. The success rate of endoscopic management dropped to 25% when treatment was initiated more than 45 days after the index surgery.

CONCLUSIONS

Purely endoscopic management was successful in 81% of cases; with 97% success rate if diagnosis earlier than 6 weeks. After four failed endoscopic procedures, a surgical approach should be considered. Delayed diagnosis appears to be a significant risk factor for failure of endoscopic treatment.

Endoscopic stent placement for the management of gastro-pleural and gastro-cutaneous fistula post laparoscopic sleeve gastrectomy: a case report

BACKGROUND

Gastro-pleural and gastro-cutaneous fistulae formation are rare yet life-threatening complications post-bariatric surgery. To our knowledge so far only limited cases of gastro-pleural and gastro-cutaneous fistulae post gastric sleeve surgery have been reported in the literature with their corresponding management. Therefore, we are reporting a case of placement of an endoscopic stent in the management of gastro-cutaneous fistula post laparoscopic sleeve gastrectomy.

CASE PRESENTATION

A 42 years old Pakistani, female morbidly obese patient, underwent laparoscopic sleeve gastrectomy. Within a week after the procedure, the patient presented with dyspnea. Workup showed a gastric leak for which percutaneous drain placement was done. Later, gastro-pleural and gastro-cutaneous fistulae were formed for which endoscopic fistula closure was done using a metallic stent.

CONCLUSION

Endoscopic stent placement is an emerging field and it is considered safe and effective for the management of complications related to bariatric surgery.

Niti-S Esophageal Mega-Stent: An Emerging Endoscopic Tool with Different Applications in the Management of Surgical Anastomotic Leaks

Introduction

Anastomotic leak (AL) is a dangerous complication in the early postoperative period after total gastrectomy or esophagectomy being associated with high mortality. Self-expandable metal stents (SEMS) play a significant role in AL management. Only one case report described the use of Mega-Stent in AL setting. The authors report a two-case series with different applications of a Niti-S esophageal Mega-Stent in AL management.

Case Report

Case 1 is a 67-year-old male who underwent an esophagectomy due to a squamous cell carcinoma of the distal esophagus. The early postoperative period was complicated with AL and gastropleural fistula. Initially, an OTSC was deployed in the dehiscence but failed to resolve AL. The esophageal Mega-Stent was further placed in-between the esophagus and the bulbus. Post-stenting contrast studies confirmed no further AL.Case 2 is an 86-year-old woman who underwent total gastrectomy with roux-en-y esophagojejunostomy due to a gastric adenocarcinoma, complicated with AL. A partially covered metal stent (PCMS) was placed to cover the anastomosis. Computed tomography confirmed leakage persistence and a second PCMS was deployed, resolving the AL. Several weeks later, both PCMSs presented ingrowth from granulation tissue. An esophageal Mega-Stent was placed (stent-in-stent technique) and 2 weeks later, all stents were removed, with no AL recurrence.

Discussion/Conclusion

SEMS placement for AL is a safe, well-established therapeutic technique. Limitations include stent migration and incomplete cover of large AL. Mega-Stent can be an emerging tool for endoscopic AL management.

Endoscopic management of refractory leak and gastro-cutaneous fistula after laparoscopic sleeve gastrectomy: a randomized controlled trial

BACKGROUND

Gastro-cutaneous fistula is a rare complication after laparoscopic sleeve gastrectomy (LSG) with incidence of occurrence 1-2%. Most of gastro-cutaneous fistulae do not respond to conservative management and need intervention either surgically or endoscopically.

METHODS

This prospective randomized clinical study included referred patients who had LSG performed at our department or other centers, and complicated with post-LSG leak or gastro-cutaneous fistula between December/2019 and March/2021. Included patients were ASA Physical status I-II. Primary and secondary outcomes were recurrence of the fistula and mortality in each group after the intervention during the 18 months follow-up period, respectively.

RESULTS

Thirty patients were randomized into two groups: Surgery Group (SG, n = 15) and Endoscopy Group (EG, n = 15). Mean age of patients was 42.3 ± 8.7 and 42.6 ± 8.3 years-old in SG and EG, respectively. Females constituted 73.3% and 80% in SG and EG, respectively. Median time-to-gastric leak post LSG was six (range: 4-7) days in both groups. SG patients were surgically managed with primary repair of the gastric fistula and gastrojejunostomy in 13 patients or converting SG into Roux-en-Y gastric bypass in two patients, while EG patients were endoscopically managed with stitching, stenting, stenting and dilation, and clipping and dilation in 5, 4, 4 and 2 patients, respectively. Incidence of recurrent leak during 1^st week was significantly higher in SG than EG (p < 0.001). No mortality reported in EG, while 2 patients died in SG (p = 0.48).

CONCLUSION

Endoscopic intervention may offer a successful modality in managing post-LSG gastric leak and gastro-cutaneous fistula that do not respond to conservative measures in stable patients.

Stent Management of Leaks After Bariatric Surgery: a Systematic Review and Meta-analysis

BACKGROUND

Despite the low rates of complications of bariatric surgery, gastrointestinal leaks are major adverse events that increase post-operative morbidity and mortality. Endoscopic treatment using self-expanding stents has been used in the therapeutic management of these complications with preliminary good results.

METHODS

We performed a systematic review and meta-analysis of self-expanding stents placement for the management of gastrointestinal leaks after obesity surgery. Overall proportion of successful leak closure, stent migration, and reoperation were analysed as primary outcomes. Secondary outcomes were patients' clinical characteristics, duration and type of stent, other stent complications, and mortality.

RESULTS

A meta-analysis of studies reporting stents was performed, including 488 patients. The overall proportion of successful leak closure was 85.89% (95% CI, 82.52-89.25%), median interval between stent placement and its removal of 44 days. Stent migration was noted in 18.65% (95% CI, 14.32-22.98%) and the overall proportion of re-operation was in 13.54% (95% CI, 9.94-17.14%). The agreement between reviewers for the collected data gave a Cohen's κ value of 1.0. No deaths were caused directly by complications with the stent placement.

CONCLUSIONS

Endoscopic placement of self-expanding stents can be used, in selected patients, for the management of leaks after bariatric surgery with a high rate of effectiveness and low mortality rates. Nevertheless, reducing stent migration and re-operation rates represents an important challenge for future studies.

Current status in endoscopic management of upper gastrointestinal perforations, leaks and fistulas

Recent advancement in endoscopic closure techniques have revolutionized the treatment of gastrointestinal perforations, leaks and fistulas. Traditionally, these have been managed surgically. The treatment strategy depends on the size and location of the defect, degree of contamination, presence of healthy surrounding tissues, patients' condition and the availability of expertise. One of the basic principles of management includes providing a barricade to the flow of luminal contents across the defect. This can be achieved with a wide range of endoscopic techniques. These include endoclips, stenting, suturing, tissue adhesives and glue, and endoscopic vacuum therapy. Each method has their distinct indications and shortcomings. Often, a combination of these techniques is required. Apart from endoscopic closure, drainage procedures by the interventional radiologist and surgical management also play an important role. In this review article, the outcomes of each of these endoscopic closure techniques in the literature is provided in tables, and practical management algorithms are being proposed.

Endoscopic Stent Placement Can Successfully Treat Gastric Leak Following Laparoscopic Sleeve Gastrectomy If and Only If an Esophagoduodenal Megastent Is Used

PURPOSE

Gastric staple line leakage (GL) is a serious complication of laparoscopic sleeve gastrectomy (LSG), with a specific mortality ranging from 0.2 to 3.7%. The current treatment of choice is stent insertion. However, it is unclear whether the type of stent which is inserted affects treatment outcome. Therefore, we aimed not only to determine the effectiveness of stent treatment for GL but also to specifically clarify whether treatment outcome was dependent on the type of stent (small- (SS) or megastent (MS)) which was used.

PATIENTS AND METHODS

A single-centre retrospective study of 23 consecutive patients was conducted to compare the outcomes of SS (n = 12) and MS (n = 11) for the treatment of GL following LSG. The primary outcome measure was the success rate of stenting, defined as complete healing of the GL without changing the treatment strategy. Treatment change or death were both coded as failure.

RESULTS

The success rate of MS was 91% (10/11) compared to only 50% (6/12) for SS (p = 0.006). An average of 2.3 ± 0.5 and 6.8 ± 3.7 endoscopies were required to achieve healing in the MS and SS groups respectively (p < 0.001). The average time to resumption of oral nutrition was shorter in the MS group (1.4 ± 1.1 days vs. 23.1 ± 33.1 days, p = 0.003).

CONCLUSIONS

Stent therapy is only effective and safe for the treatment of GL after LSG if a MS is used. Treatment with a MS may not only increase treatment success rates but may also facilitate earlier resumption of oral nutrition and shorten the duration of hospitalization.

A Comprehensive Review of Endoscopic Management of Sleeve Gastrectomy Leaks

BACKGROUND

Bariatric surgery leaks result in significant morbidity and mortality. Experts report variable therapeutic approaches, without uniform guidelines or consensus.

OBJECTIVE

To review the pathogenesis, risk factors, prevention, and treatment of gastric sleeve leaks, with a focus on endoscopic approaches. In addition, the efficacy and success rates of different treatment modalities are assessed.

DESIGN

A comprehensive review was conducted using a thorough literature search of 5 online electronic databases (PubMed, PubMed Central, Cochrane, EMBASE, and Web of Science) from the time of their inception through March 2020. Studies evaluating gastric sleeve leaks were included. MeSH terms related to "endoscopic," "leak," "sleeve," "gastrectomy," "anastomotic," and "bariatric" were applied to a highly sensitive search strategy. The main outcomes were epidemiology, pathophysiology, diagnosis, treatment, and outcomes.

RESULTS

Literature search yielded 2418 studies of which 438 were incorporated into the review. Shock and peritonitis necessitate early surgical intervention for leaks. Endoscopic therapies in acute and early leaks involve modalities with a focus on one of: (i) defect closure, (ii) wall diversion, or (iii) wall exclusion. Surgical revision is required if endoscopic therapies fail to control leaks after 6 months. Chronic leaks require one or more endoscopic, radiologic, or surgical approaches for fluid collection drainage to facilitate adequate healing. Success rates depend on provider and center expertise.

CONCLUSION

Endoscopic management of leaks post sleeve gastrectomy is a minimally invasive and effective alternative to surgery. Their effect may vary based on clinical presentation, timing or leak morphology, and should be tailored to the appropriate endoscopic modality of treatment.

Management of Leaks Following Laparoscopic Sleeve Gastrectomy Using Specifically Designed Large Covered Metal Stents

BACKGROUND

Leaks are the major complication associated with laparoscopic sleeve gastrectomy.

OBJECTIVE

The study aimed to assess the efficacy and safety of specifically designed large covered metal stents for the management of post-laparoscopic sleeve gastrectomy leaks.

METHODS

Prospectively collected databases from three Italian Endoscopy Units were reviewed. The primary outcome of the study was to evaluate the clinical success of stents placement, defined as complete resolution of clinical and laboratory signs of sepsis with radiological evidence of leak closure. Secondary outcomes were stent-related adverse events and mortality.

RESULTS

Twenty-one patients (67% females, mean age 45 years) were included in the study and a total of 26 stents were placed. Technical success of stent placement was achieved in all cases (100%). Clinical success was observed in 85.5% of patients. Stent-related adverse events occurred in 9 patients (43%), with stent migration as the most frequent complication (33%). Adverse events were more frequently observed in patients who had undergone bariatric surgery prior to laparoscopic sleeve gastrectomy compared to patients without previous surgery (83% et al. 27%, p=0.018).

CONCLUSION

The placement of specifically designed covered metal stents appears to be an effective and safe therapeutic approach for post-laparoscopic sleeve gastrectomy leaks. Stent migration can be a frequent complication.

Gastric Fistula After Sleeve Gastrectomy: Clinical Features and Treatment Options

PURPOSE

To trace the clinical profile of fistula cases after sleeve gastrectomy (SG) and evaluate the efficacy and safety of endoscopic treatments and the admission costs of these patients.

METHODS

This is a retrospective study of patients who developed gastric fistulas after SG. All patients were submitted to surgical and/or endoscopic interventions (self-expandable stent, septotomy, and balloon dilation). The main studied variables were need for reoperation, number of endoscopic procedures, endoscopic complications, time until fistula diagnosis, fistula location, time until resolution, length of hospital stay, and health costs.

RESULTS

The sample was mainly female (76.2%) with a mean age of 39.5 years and a BMI of 39.6 kg/m². In 90.5% of cases, the fistula occurred in the topography of the His angle. Thirteen patients required surgical intervention. Of the patients who underwent endoscopic interventions, it was necessary to place more than one self-expandable stent of a maximum duration of 4 weeks. Six patients underwent more than two sessions of septotomy. There was one case of bleeding after septotomy. Dilatation was required in 71.4% of patients and an average of two sessions (1-5) per patient. The diagnosis of fistula occurred 14.4 days after surgery. The average time to resolve fistulas was 50.6 days. The average hospital stay was 75.8 days. The total cost of hospitalization was on average US$ 75,180.00.

CONCLUSION

The surgical and endoscopic treatment of gastric fistulas after SG was safe and effective. There was a very low rate of complications. The time of onset of fistulas was not decisive for patient improvement.

Endoscopic treatment of postoperative esophagogastric leaks with fully covered self-expanding metal stents

BACKGROUND

the management of postoperative esophageal leaks is a huge therapeutic challenge. Thanks to the advances in endoscopy, treatment with esophageal stents has been proposed as a valid option.

AIMS

the main objective of the study was to evaluate the effectiveness and safety of the use of fully covered esophageal metal stents in the treatment of postoperative esophageal leaks.

METHODS

a retrospective observational study was performed in patients with postoperative esophageal leaks, treated with fully covered self-expandable metal stents between June 2011 and May 2018.

RESULTS

twenty-five patients were evaluated and 34 stents were placed. The closure of the leak was observed in 21 patients after removal of the stent, with an overall technical success rate of 84 %. The mean time with a stent placed for closure of the fistula was 55.7 ± 27.11 days/patient (mean of 39 ± 24.30 days/stent). The most frequent complication was a partial distal stent migration (7/34 stents), followed by five cases of complete migration into the stomach.

CONCLUSIONS

endoscopic treatment with fully covered self-expandable metal stents seems to be an effective and safe first-line treatment for postoperative esophageal leaks, according to the experience in our center.

Endoscopic management of leaks and fistulas after bariatric surgery: a systematic review and meta-analysis

Background

Endoscopic techniques have become the first-line therapy in bariatric surgery-related complications such as leaks and fistulas. We performed a systematic review and meta-analysis on the effectiveness of self-expandable stents, clipping, and tissue sealants in closing of post-bariatric surgery leak/fistula.

Methods

A systematic literature search of the Medline/Scopus databases was performed to identify full-text articles published up to February 2019 on the use of self-expandable stents, clipping, or tissue sealants as primary endoscopic strategies used for leak/fistula closure. Meta-analysis of studies reporting stents was performed with the PRISMA guidelines.

Results

Data concerning the efficacy of self-expanding stents in the treatment of leaks/fistulas after bariatric surgery were extracted from 40 studies (493 patients). The overall proportion of successful leak/fistula closure was 92% (95% CI, 90–95%). The overall proportion of stent migration was 23% (95% CI, 19–28%). Seventeen papers (98 patients) reported the use of clipping: the over-the-scope clips (OTSC) system was used in 85 patients with a successful closure rate of 67.1% and a few complications (migration, stenosis, tear). The successful fistula/leak closure using other than OTSC types was achieved in 69.2% of patients. In 10 case series (63 patients), fibrin glue alone was used with a 92.8–100% success rate of fistula closure that usually required repeated sessions at scheduled intervals. The complications of fibrin glue applications were reported in only one study and included pain and fever in 12.5% of patients.

Conclusions

Endoscopic techniques are effective for management of post-bariatric leaks and fistulas in properly selected patients.

Electronic supplementary material

The online version of this article (10.1007/s00464-020-07471-1) contains supplementary material, which is available to authorized users.

Efficacy and Safety of Stents in the Treatment of Fistula After Bariatric Surgery: a Systematic Review and Meta-analysis

Fistula development is a serious complication after bariatric surgery. We performed a systematic review and meta-analysis to assess the efficacy of fistula closure and complications associated with endoscopic stent treatment of fistulas, developed after bariatric surgeries, particularly Roux-en-Y gastric bypass (RYGB) and gastric sleeve (GS). Studies involving patients with fistula after RYGB or GS and those who received stent treatment only were selected. The analyzed outcomes were overall success rate of fistula closure, mean number of stents per patient, mean stent dwelling time, and procedure-associated complications. Current evidence from identified studies demonstrates that, in selected patients, endoscopic stent treatment of fistulas after GS or RYGB can be safe and effective.

Endoscopic Management of Gastrobronchial Fistula after Laparoscopic Sleeve Gastrectomy: A Case Report

Bariatric surgery has rapidly emerged as a modality for managing morbid obesity; however, despite being considered safe, some complications do exist. Formation of a gastrobronchial fistula is a rare complication of laparoscopic sleeve gastrectomy that is associated with high morbidity and mortality. Nowadays, novel endoscopic techniques have widely been adopted in the management of such cases, as they provide minimally invasive options that decrease the morbidity and mortality. Here, the author presents a report of a middle-aged, morbidly obese male who had previously undergone laparoscopic sleeve gastrectomy and returned with a 3-month history of productive cough. On upper gastrointestinal series, the patient was found to have a fistula communicating the stomach to the bronchial tree of his left lung (gastrobronchial fistula). He was treated with endoscopic fistula closure using an over-the-scope clip and a fully-covered Niti-S metallic stent. After this treatment, the patient's symptoms improved dramatically, and the stent was successfully removed 12 weeks later. This report highlights the management of a patient with gastrobronchial fistula formation following laparoscopic sleeve gastrectomy as well as provides a literature review of using combined endoscopic management to treat gastrobronchial fistulas.

Comparison between LigaSure™ and Harmonic® in Laparoscopic Sleeve Gastrectomy: A Single-Center Experience on 422 Patients

BACKGROUND

New laparoscopic devices, such as electrothermal bipolar-activated devices (LigaSure™ (LS)) or ultrasonic systems (Harmonic® scalpel (HS)), have been applied recently to bariatric surgery allowing to reduce blood loss and surgical risks. The aim of this study was to retrospectively compare intraoperative performance of HS and LS, postoperative results, and clinical outcomes in a large cohort of patients undergoing LSG.

METHODS

Data from 422 morbidly obese patients undergoing LSG in our Bariatric Unit at the Advanced Biomedical Sciences Department of the "Federico II" University of Naples (Italy) between January 2009 and December 2017 were retrospectively analyzed. Subjects were divided into two groups (HS and LS), and operative time, intraoperative complications, and postoperative (within 30 days from surgery) complications were compared. Bleeding from the omentum or from the staple line, use of hemostatic clips, and absorbable hemostat were recorded as intraoperative complications; hemorrhages, abscess formation, gastric leaks, fever, and mortality were considered as postoperative complications.

RESULTS

Statistical analysis showed no difference in terms of baseline demographics between the two cohorts. Operative time (48 ± 9 vs 49 ± 6 min, p=0.646) and the rates of intraoperative and postoperative complications did not significantly differ between groups.

CONCLUSION

Harmonic® and LigaSure™ are both useful tools in bariatric surgery, and these two advanced power devices are user-friendly and can facilitate surgeon work; from this point of view, the choice of the energy device should be based on the preference of the surgeon and on the hospital costs policy and availability.

Predictors of fat-free mass loss 1 year after laparoscopic sleeve gastrectomy

PURPOSE

Laparoscopic sleeve gastrectomy (LSG) is one of the most frequently performed bariatric surgery interventions because of its safety and efficacy. Nevertheless, concerns have been raised on its detrimental effect on patient nutritional state that can ultimately lead to the loss of fat-free mass (FFM). There is interest in identifying predictors for the early identification of patients at risk of this highly unwanted adverse because they could benefit of nutritional preventive interventions. Therefore, we investigated whether anthropometric parameters, body composition or resting energy expenditure (REE) measured before surgery could predict FFM loss 1 year after LSG.

METHODS

Study design was retrospective observational. We retrieved data on body weight, BMI, body composition and REE before and 1 year after LSG from the medical files of 36 patients operated on by LSG at our institutions. Simple regression, the Oldham's method and multilevel analysis were used to identify predictors of FFM loss.

RESULTS

Averaged percentage FFM loss 1 year after LSG was 17.0 ± 7.7% with significant differences between sexes (20.8 ± 6.6 in males and 12.2 ± 6.1% in females, p < 0.001). FFM loss was strongly predicted by pre-surgery FFM and this effect persisted also after correcting for the contribution of sex.

CONCLUSIONS

High FFM values before surgery predict a more severe FFM loss after LSG. This factor could also account for the higher FFM loss in men than in women. Our finding could help in the early identification of patient requiring a nutritional support after LSG.

Endoscopic Full-Thickness Defects and Closure Techniques. ACTA ACUST UNITED AC. 2018;16:386-405. [PMID: 30382572 DOI: 10.1007/s11938-018-0199-6]

PURPOSE OF REVIEW

Gastrointestinal transmural defects are defined as total rupture of the gastrointestinal wall and can be divided into three main categories: perforations, leaks, and fistulas. Due to an increase in the number of therapeutic endoscopic procedures including full-thickness resections and the increase incidence of complications related to bariatric surgeries, there has been an increase in the number of transmural defects seen in clinical practice and the number of non-invasive endoscopic treatment procedures used to treat these defects.

RECENT FINDINGS

The variety of endoscopic approaches and devices, including closure techniques using clips, endoloop, and endoscopic sutures; covering techniques such as the cardiac septal occluder device, luminal stents, and tissue sealants; and drainage techniques including endoscopic vacuum therapy, pigtail, and septotomy with balloon dilation are transforming endoscopy as the first-line approach for therapy of these conditions. In this review, we describe the various transmural defects and the endoscopic techniques and devices used in their closure.

Early and late complications of bariatric operation

Weight loss surgery is one of the fastest growing segments of the surgical discipline. As with all medical procedures, postoperative complications will occur. Acute care surgeons need to be familiar with the common problems and their management. Although general surgical principles generally apply, diagnoses specific to the various bariatric operations must be considered. There are anatomic considerations which alter management priorities and options for these patients in many instances. These problems present both early or late in the postoperative course. Bariatric operations, in many instances, result in permanent alteration of a patient’s anatomy, which can lead to complications at any time during the course of a patient’s life. Acute care surgeons diagnosing surgical emergencies in postbariatric operation patients must be familiar with the type of surgery performed, as well as the common postbariatric surgical emergencies. In addition, surgeons must not overlook the common causes of an acute surgical abdomen—acute appendicitis, acute diverticulitis, acute pancreatitis, and gallstone disease—for these are still among the most common etiologies of abdominal pathology in these patients.

Results following laparoscopic sleeve gastrectomy in elderly obese patients: a single center experience with follow-up at three years

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) represents the most performed bariatric surgical procedure worldwide. Morbid Overweight in elderly patients is becoming a significant health problem even in Italy. As well as in younger age groups, bariatric surgery could be indicated even in this subset of patients. However the advantages and results of LSG in patients over 60 years old have received minimal attention.

METHODS

The records of 375 patients underwent LSG between 2008 and 2016 were reviewed. In the entire series 18 patients were aged 60 years or older at the time of surgery. Since a 3 years follow-up was available for 12 patients out of the 18 aged over 60 we included in the study only these. General epidemiologic data, clinical findings, BMI and comorbidities surgical treatment and follow-up data were collected; postoperative measurements such as operative time, intraoperative complications, mortality rate, length of stay, incidence of early and late complications, Body mass Index (BMI), excess weight loss rate (EWL%) and comorbidities resolution were also recorded.

RESULTS

LSG was successfully performed for all geriatric patients. Global complications rate was 16.6% At 3 years mean BMI was 34.4±3.8 with a mean EWL% 66.1±31.9. Postoperative resolution of obesity comorbidities was observed; Hypertension (71.4%), type 2 Diabetes Mellitus (T2DM) (50.0%), obstructive sleep apnea syndrome (OSAS) (66.6%) respectively. No intraoperative complications or mortality were recorded.

CONCLUSIONS

LSG offered cure in geriatric patients affected by morbid obesity for weight loss and comorbidities resolution. Larger studies are necessary to analyze and minimize the incidence of postoperative complications associated to this surgical procedure in elderly patients.

Endoscopic Therapy for Treatment of Staple Line Leaks Post-Laparoscopic Sleeve Gastrectomy (LSG): Experience from a Large Bariatric Surgery Centre in New Zealand

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed bariatric procedures for treatment of morbid obesity. Despite its popularity, it is not without risks, the most serious of which is the staple line leak. Staple line leaks are difficult to manage and require significant resources in the form of surgical, radiological and endoscopic interventions; long hospital and intensive care stay and significant morbidity. International experience is slowly emerging, but there are still no clear guidelines regarding optimal management of leaks. This study aims to describe the experience of endoscopic management of these leaks by the authors and the development of a customised stent for this condition.

METHODS

Middlemore Hospital is the largest bariatric surgery centre in New Zealand. Since June 2007, a total of 21 patients have received endotherapy for post-LSG leak management. Treatment included the deployment of primary self-expanding metal stents (SEMS) across the leak site, combined with complementary endoscopic modalities. Persistent leaks were treated with follow-up stenting. This study aimed to evaluate the effectiveness of post-LSG staple line leak management at Middlemore Hospital.

RESULTS

A total of 20/21 (95 %) patients now have resolved leaks following a mean of 75 days of treatment (median 47, range 9-187). The mean number of endoscopic procedures required was five. Inpatient stay and average duration till leak resolution has been notably reduced since the addition of customised stents. Clinically significant stent migration occurred in 19 % of primary stents.

CONCLUSION

The use of SEMS in conjunction with complementary endotherapy has shown to be both safe and effective in treating sleeve leaks; however, migration is the limiting factor for optimal management. Recent improvements in stent design, such as the one proposed in this paper, show promise in addressing this problem. Earlier use of SEMS seems to reduce the time till closure as well as the total hospital stay, as is apparent from our data.

Gastroesophageal stenting for the management of post sleeve gastrectomy leak. A single institution experience

OBJECTIVES

To retrospectively evaluate the effectiveness of gastroesophageal stenting for post sleeve gastrectomy staple line leaks using removable self-expandable stents.

METHODS

Between April 2012 and June 2015, 12 consecutive patients (6 males) with mean age of 34 years (21-38 years) presented with staple line leak 1-8 weeks after the operation (mean 2.8 weeks). Patients underwent gastroesophageal stenting by interventional radiology. A total of 23 stents were deployed with mean length of 17.8 cm (7-24 cm) and mean diameter 25.6 mm (18-36 mm). Stent re-insertion was needed in 7 patients (9 procedure), while 6 patients required percutaneous collection drainage and 3 patients required endoscopic glue injection with clipping. Two stent removal procedures were carried out under endoscopic visualization after failed stent capture under fluoroscopy, while the remaining stents were successfully removed by interventional radiology. Results: Stent placement was technically successful in all patients. Stent migration occurred in 6 patients (50%). There is a tendency for stent migration with shorter stent length (R= -0.557, p=0.008). The mean duration of stenting was 60.5 days (14-137 days). All patients underwent stent removal and resumed oral intake with no recurrence of leak at a mean follow up time of 190 days (14-410 days). Complications included gastrointestinal bleeding (n=1), proximal esophageal stricture (n=1) and stent occlusion (n=1).

CONCLUSION

Gastroesophageal stenting as a primary measure after diagnosis of early post sleeve gastrectomy leak appears to offer a safe and effective alternative option in obviating repeat surgical interventions. Minimally invasive interventions may still be required for the management of persistent leak.

Review article including treatment algorithm: endoscopic treatment of luminal complications after bariatric surgery

The worldwide number of performed bariatric surgeries is increasing continuously, whereas laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy are conducted most frequently. Alongside with the usual post-operative and metabolic complications, luminal complications such as anastomotic bleeding, ulceration, leakage, fistula formation, enlargement and stenosis of the anastomosis may occur. Evolution of interventional endoscopy frequently allows endoscopic management of complications, avoiding surgical interventions in most cases. Here, we review the various luminal complications after bariatric surgery with a focus on their endoscopic management.

Endoluminal solutions to bariatric surgery complications: A review with a focus on technical aspects and results

Obesity is a growing problem in developed countries, and surgery is the most effective treatment in terms of weight loss and improving medical comorbidity in a high proportion of obese patients. Despite the advances in surgical techniques, some patients still develop acute and late postoperative complications, and an endoscopic evaluation is often required for diagnosis. Moreover, the high morbidity related to surgical reintervention, the important enhancement of endoscopic procedures and technological innovations introduced in endoscopic equipment have made the endoscopic approach a minimally-invasive alternative to surgery, and, in many cases, a suitable first-line treatment of bariatric surgery complications. There is now evidence in the literature supporting endoscopic management for some of these complications, such as gastrointestinal bleeding, stomal and marginal ulcers, stomal stenosis, leaks and fistulas or pancreatobiliary disorders. However, endoscopic treatment in this setting is not standardized, and there is no consensus on its optimal timing. In this article, we aim to analyze the secondary complications of the most expanded techniques of bariatric surgery with special emphasis on those where more solid evidence exists in favor of the endoscopic treatment. Based on a thorough review of the literature, we evaluated the performance and safety of different endoscopic options for every type of complication, highlighting the most recent innovations and including comparative data with surgical alternatives whenever feasible.

Evolution of endoscopic treatment of sleeve gastrectomy leaks: from partially covered to long, fully covered stents

BACKGROUND

Laparoscopic sleeve gastrectomy (SG) has become a widely accepted option in the treatment of morbid obesity. Gastric leaks after SG occur in .9%-2.2% of the patients, mostly at the gastroesophageal junction. The current treatment algorithm includes drainage, antibiotics, nutritional support, and endoluminal control.

OBJECTIVES

Our hypothesis is that long, fully covered stents represent a safe, effective solution for SG leaks.

SETTING

University hospital.

METHODS

A retrospective analysis of our prospectively collected bariatric database was performed between June 2014 and May 2016. We included all patients treated for leaks after SG. Endoscopic treatment included partially covered metallic stent (Wallstent, Boston Scientific, Galway, Ireland), fully covered stent (Mega stent, Taewoong Medical Industries, Gyeonggi-do, South Korea), over-the-scope clip (Ovesco Endoscopy, Tubingen, Germany), and internal pigtail drainage.

RESULTS

A total of 872 SGs were performed. Overall, 10 of 872 patients (1.1%) developed a gastric leak. One patient was an outside referral. The 11 patients underwent endoscopic treatment accompanied by either percutaneous or laparoscopic abscess drainage. Endoscopic fistula closure at the gastroesophageal junction was achieved in 10 of 11 cases and the average time for closure was 9.9 (range: 4-24) weeks. One patient developed a second leak in the antrum, treated by subtotal gastrectomy. Overall, treatment with Wallstent failed in 3 of 5 patients, and these patients were eventually successfully treated with a Mega stent. The initial use of long, fully covered stents was successful in 5 of 6 cases.

CONCLUSION

Long, fully covered stents appear to be a good alternative to traditional stents either as primary treatment or after failure of other endoscopic treatments.

Endoscopic Approach for Major Complications of Bariatric Surgery

As lifestyle and diet patterns have become westernized in East Asia, the prevalence of obesity has rapidly increased. Bariatric surgeries, such as Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and laparoscopic adjustable gastric banding (LAGB), are considered the first-line treatment option in patients with severe obesity. However, postoperative complications have increased and the proper management of these complications, including the use of endoscopic procedures, has become important. The most serious complications, such as leaks and fistulas, can be treated with endoscopic stent placement and injection of fibrin glue, and a novel full-thickness closure over-the-scope clip (OTSC) has been used for treatment of postoperative leaks. Stricture at the gastrojejunal (GJ) anastomosis site after RYGB or incisura angularis in SG can be managed using stents or endoscopic balloon dilation. Dilation of the GJ anastomosis or gastric pouch may lead to failure of weight loss, and the use of endoscopic sclerotherapy, novel endoscopic suturing devices, and OTSCs have been attempted. Intragastric migration of the gastric band can be successfully treated using various endoscopic tools. Endoscopy plays a pivotal role in the management of post-bariatric complications, and close cooperation between endoscopists and bariatric surgeons may further increase the success rate of endoscopic procedures.

An Endoscopic Strategy Combining Mega Stents and Over-The-Scope Clips for the Management of Post-Bariatric Surgery Leaks and Fistulas (with video)

BACKGROUND AND AIMS

Endoscopic stenting has proved effective in the management of post-surgical leaks but is strongly hampered by the high rate of stent migration. In this study, we evaluate our experience with a new approach involving the use of novel ultra-large expandable stents tailored for bariatric surgery leaks (Mega stents), combined with the use of the innovative over-the-scope clips (OTSC).

METHODS

Retrospective analysis of patients with post-bariatric surgery leaks managed at our institution by an approach combining Mega stents and over-the-scope clips.

RESULTS

Twenty-two patients were treated for post-bariatric surgery leaks; 13 (59%) had a sleeve gastrectomy while nine (41%) had a RYGB. A total of 30 stents were inserted. Successful endoscopic insertion and removal were achieved in all patients. OTSC clips were applied in 12 patients (55%); five simultaneously with stents and seven after stent removal. Primary closure (after one endoscopic procedure) was achieved in 13 patients (59%) and in a total of 18 patients after multiple endoscopic procedures (82%). An average of 1.4 stents and 2.8 endoscopic procedures were required per patient. Stent migration occurred in four patients (18%), and all were retrievable endoscopically. Other complications included retrosternal pain and vomiting in 20 patients (91%) including one necessitating early removal, bleeding in two patients (9%), and perforation and esophageal stricture in one patient each (5%). Two mortalities were encountered, and one of them was stent-related (bleeding).

CONCLUSION

Mega stents are effective in the management of post-bariatric surgery leaks. The combined use of Mega stents and OTSC clips is associated with a low incidence of migration and a low number of stents and procedures required per patient.

Endoscopic stenting for laparoscopic sleeve gastrectomy leaks

OBJECTIVE

Laparoscopic sleeve gastrectomy is a widely accepted and effective bariatric surgery method. The rate of leakage at the staple-line has been reported to be between 1.5 and 5%. Aside from the use of percutaneous drainage, re-laparoscopy, or abdominal sepsis control by laparotomy, endoscopic esophagogastric stent placement is increasingly preferred as a treatment method. Because laparoscopic sleeve gastrectomy is a widely used modality in our hospital, we aimed to evaluate the rate of leaks and the results of stent placements in our patients.

MATERIAL AND METHODS

Between January 1^st 2010 and August 31^st 2014, laparoscopic sleeve gastrectomy was performed on 236 patients by three surgeons. The demographic information and postoperative discharge summaries were collected and analyzed with the permission of the hospital ethics committee. Information about leak treatment management was also collected.

RESULTS

Leaks after laparoscopic sleeve gastrectomy in four patients were stented in the first postoperative month. Short (12 cm) Hanora® (M.I.Tech, Gyeonggi-do, Korea) self-expandable coated stents were placed in two patients, and long (24 cm) Hanora® self-expandable coated stents were placed in the other two. The stents were removed after one month in two patients, two and a half months later in one, and five months later in another patient. The leaks were demonstrated to be healed in all patients after stent removal. Endoscopic stent revision was performed in one patient due to migration of the stent and in another for stent breakage.

CONCLUSION

The success rate of treatment of leaks after laparoscopic sleeve gastrectomy by stent placement has been variable in the literature. The success in early stent placement has been shown to be related to physician expertise. According to the results of our patients, we suggest that endoscopic stent placement in the early stage after controlling sepsis is an effective method in the management of leaks.

Management of gastric leaks after laparoscopic sleeve gastrectomy for morbid obesity: A tertiary care experience and design of a management algorithm

BACKGROUND:

Laparoscopic sleeve gastrectomy (LSG) is the most commonly performed ‘standalone’ bariatric procedure in India. Staple line gastric leaks occur infrequently but cause significant and prolonged morbidity. The aim of this retrospective study was to analyse the management of patients with a gastric leak after LSG for morbid obesity at our institution.

PATIENTS AND METHODS:

From February 2008 to 2014, 650 patients with different degrees of morbid obesity underwent LSG. Among these, all those diagnosed with a gastric leak were included in the study. Patients referred to our institution with gastric leak after LSG were also included. The time of presentation, site of leak, investigations performed, treatment given and time of closure of all leaks were analysed.

RESULTS:

Among the 650 patients who underwent LSG, 3 (0.46%) developed a gastric leak. Two patients were referred after LSG was performed at another institution. The mean age was 45.60 ± 15.43 years. Mean body mass index (BMI) was 44.79 ± 5.35. Gastric leak was diagnosed 24 h to 7 months after surgery. One was early, two were intermediate and two were late leaks. Two were type I and three were type II gastric leaks. Endoscopic oesophageal stenting was used variably before or after re-surgery. Re-surgery was performed in all and included stapled fistula excision (re-sleeve), suture repair only or with conversion to roux-en-Y gastric bypass or fistula jujenostomy. There was no mortality.

CONCLUSION:

Leakage closure time may be shorter with intervention than expectant management. Sequence and choice of endoscopic oesophageal stenting and/or surgical re-intervention should be individualized according to clinical presentation.

Laparo-Endoscopic Gastrostomy (LEG) Decompression: a Novel One-Time Method of Management of Gastric Leaks Following Sleeve Gastrectomy

BACKGROUND

Leakage is the most feared and challenging complication following laparoscopic sleeve gastrectomy (LSG) as it can either be life-threatening or lead to major morbidity. Its management can be very complex. Endoscopic stents seem to be the mainstay of the current modality of treatment but are associated with a high rate of complications and also need supportive procedures for sepsis control and feeding. We aimed to approach this problem through a one-step intervention, achieving three objectives: a prolonged decompression of the gastric tube through a laparo-endoscopically placed gastrostomy, feeding jejunostomy and external drainage.

METHODS

Between 2014 January and March 2015, seven patients were managed for gastric leaks (post LSG) in our center by this novel approach. Their records were reviewed for details like prior operation, presence of comorbidities, if revisional surgery, day of presentation following surgery, intraoperative findings, post-op recovery, length of hospital stay, and time to heal. The results were tabulated and studied.

RESULTS

Three were post primary LSG. Four were following revisional surgeries. Six out of seven (85.7 %) healed without alternative intervention. One patient with a large rent was managed by fistulojejunostomy. The average length of stay was 20.7 days. All patients were on postoperative enteral feeding through jejunostomy. There were no gastrostomy-related complications or mortality.

CONCLUSIONS

Laparo-endoscopic gastrostomy (LEG) decompression is a feasible, single-step, successful procedure in managing post LSG leaks and may be a viable alternative to avoid stent-related morbidity.

Major complications of bariatric surgery: endoscopy as first-line treatment

Leaks are the most frequent early postoperative complication in the two most popular bariatric procedures, Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy. Multimodal therapy based on self-expandable stent insertion 'to cover' the defect is the most widely documented technique to date with a reported success rate >80%. Additional experimental techniques 'to close' the defect or 'to drain' the paradigestive cavity have been reported with encouraging results. The role of endoscopy in early postoperative bleeding is limited to management of bleeds arising from fresh sutures and the diagnosis of chronic sources of bleeding such as marginal ulcer after RYGB. Post-RYGB stricture is a more delayed complication than leaks and the role of endoscopic dilation as a first-line treatment in this indication is well documented. Ring and band placement are outdated procedures for obesity treatment, but might still be an indication for endoscopic removal, a technique which does not compromise further surgery, if needed.

Endoscopic modalities for upper gastrointestinal leaks, fistulae and perforations

Background

Endotherapy techniques are a recent addition to the suite of non‐surgical and minimally invasive strategies to manage patients with perforations, leaks and fistulae. The emergency nature of these conditions and the heterogeneity of pathologies encountered create difficulties when trying to select appropriate tools in these complex situations. The purpose of this article is to review experience at a tertiary academic centre, describe the various endoscopic tools available and the situations where they can be considered for use.

Methods

Single‐centre series and review of the published literature.

Results

Of 64 patients, 57 were successfully treated using endoscopic therapy, with surgery used only to provide drainage and suture fully covered metal stents in place to prevent migration.

Discussion

Selection of an appropriate endotherapy or stent for a patient with an oesophago‐gastric perforation or fistula requires an understanding of the anatomy and physiology underlying the patient's presentation and an understanding of the strengths and weaknesses of the available methods. Standard surgical principles of drainage, avoidance of distal obstruction and nutrition remain central to successful outcomes. A combination of surgical and endoscopic treatments may reduce the number of required treatments and can provide the ability to anchor fully covered stents to prevent them from migrating.

Endoscopic Therapy for Treatment of Staple Line Leaks Post-Laparoscopic Sleeve Gastrectomy (LSG): Experience from a Large Bariatric Surgery Centre in New Zealand

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed bariatric procedures for treatment of morbid obesity. Despite its popularity, it is not without risks, the most serious of which is the staple line leak. Staple line leaks are difficult to manage and require significant resources in the form of surgical, radiological and endoscopic interventions; long hospital and intensive care stay and significant morbidity. International experience is slowly emerging, but there are still no clear guidelines regarding optimal management of leaks. This study aims to describe the experience of endoscopic management of these leaks by the authors and the development of a customised stent for this condition.

METHODS

Middlemore Hospital is the largest bariatric surgery centre in New Zealand. Since June 2007, a total of 21 patients have received endotherapy for post-LSG leak management. Treatment included the deployment of primary self-expanding metal stents (SEMS) across the leak site, combined with complementary endoscopic modalities. Persistent leaks were treated with follow-up stenting. This study aimed to evaluate the effectiveness of post-LSG staple line leak management at Middlemore Hospital.

RESULTS

A total of 20/21 (95 %) patients now have resolved leaks following a mean of 75 days of treatment (median 47, range 9-187). The mean number of endoscopic procedures required was five. Inpatient stay and average duration till leak resolution has been notably reduced since the addition of customised stents. Clinically significant stent migration occurred in 19 % of primary stents.

CONCLUSION

The use of SEMS in conjunction with complementary endotherapy has shown to be both safe and effective in treating sleeve leaks; however, migration is the limiting factor for optimal management. Recent improvements in stent design, such as the one proposed in this paper, show promise in addressing this problem. Earlier use of SEMS seems to reduce the time till closure as well as the total hospital stay, as is apparent from our data.

Endoscopic management of bariatric surgical complications

PURPOSE OF REVIEW

Bariatric surgery is recognized as the most effective treatment against obesity as it results in significant weight reduction and a high rate of remission of obesity-related comorbidities. However, bariatric surgery is not uncommonly associated with complications and an endoscopic approach to management is preferred over surgical reintervention. This review illustrates the latest developments in the endoscopic management of bariatric surgical complications.

RECENT FINDINGS

For successful management of complications, precipitating and perpetuating factors must be addressed in addition to directing therapy at the target pathology. Endoscopy is well tolerated even in the acute postoperative setting when performed carefully with CO2 insufflation. Chronic proximal staple-line leaks/fistulas frequently do not respond to primary closure with diversion therapy, and a new technique of stricturotomy has been reported to improve outcomes. Innovations in the field of transoral endoscopic instruments have led to the development of a single-session entirely internal endoscopic retrograde cholangiopancreatography by creating a gastrogastric anastomosis.

SUMMARY

Endoscopy allows for early diagnosis and prompt institution of therapy and should, therefore, be the first-line intervention in the management of complications of bariatric surgery in patients who do not need urgent surgical intervention. Computed tomography-guided drainage may be necessary in patients with drainable fluid collections.

VIDEO ABSTRACT

http://links.lww.com/COG/A11.

Staple-line leak after sleve gastrectomy in obese patients: A hot topic in bariatric surgery

Laparoscopic sleeve gastrectomy is a surgical procedure that is being increasingly performed on obese patients. Among its complications, leaks are the most serious and life threatening. The placement of esophageal, covered, self-expandable metal stents in these cases has been performed by many authors but reports on the outcome of this procedure are limited and the technical aspects are not well defined. Stent migration is the main complication of the procedure and poses a challenge to the surgeon, with a limited number of options. Here we evaluate the technical and clinical outcome of a new, dedicated, self-expanding metal stent, comparing the advantages of this stent to those traditionally used to treat staple-line leak after sleeve gastrectomy. While published data are limited, they seem support the use of this kind of new stent as the best option for the stenting treatment of a staple-line leak after sleeve gastrectomy, over other kinds of stents. Further studies based on larger series are needed to better evaluate patient outcome.