© Springer Science+Business Media New York 2015
Ninh T. Nguyen, Robin P. Blackstone, John M. Morton, Jaime Ponce and Raul J. Rosenthal (eds.)The ASMBS Textbook of Bariatric Surgery10.1007/978-1-4939-1206-3_4040. Experimental Alternatives in Bariatric Surgery
(1)
Department of General Surgery, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
(2)
Department of Gastrointestinal Surgery, The Ohio State University Medical Center, 410 West 10th Ave. N717 Doan Hall, Columbus, OH 43210, USA
(3)
Division of GI/Minimally Invasive Surgery, Surgery Loyola University Medical Center, Stritch School of Medicine, 2160 South First Avenue Bldg., 110- Room 3291, Maywood, IL 60153, USA
Chapter Objectives
1.
Describe the role of current endoluminal bariatric therapies in the management of morbid obesity and analyze future directions of this form of therapy.
2.
Describe the results of current innovative surgical techniques for management of morbid obesity.
3.
Describe the principles of neurohormonal modulation and current results in management of morbid obesity.
Introduction
Bariatric surgery has gained tremendous popularity over the past two decades. This has been related in part to the increasing worldwide obesity epidemic and to the introduction of minimally invasive techniques [1, 2]. The quest for superior and even less invasive procedures continues to evolve with the development of less invasive devices and emerging procedures and technology.
Bariatric surgery remains the most effective treatment for obesity- and weight-related comorbidities [3]. However, surgical intervention is often underutilized for a multitude of reasons. Limitations may include side effects, insurance restrictions, and accessibility. Currently, only a small percent of qualifying patients have access to and undergo surgical procedures for weight loss and control or resolution of weight-related illnesses. Future direction should aim at developing therapies that are less invasive, safer, and potentially allow for greater acceptance and accessibility. These interventions should not only fill the gap between medical therapy (medications and lifestyle modifications) and bariatric surgery, but should also complement our scope of therapy in the management of obesity.
Endoluminal Bariatric Therapies (EBTS)
Flexible endoscopy has played a key role as a diagnostic and therapeutic modality in the management of the bariatric patient. Esophagogastroduodenoscopy (EGD) has become part of the routine preoperative evaluation and an invaluable procedure in the perioperative phase. Intraoperatively it is used not only in investigation of the integrity of an anastomosis or staple line, but also to evaluate for hemorrhage. It has also become the procedure of choice for the diagnosis and treatment of common postoperative complications such as strictures, gastrointestinal bleeding, and leaks [4, 5].
A wide range of EBTs is in various developmental stages and may offer potentially less invasive alternatives with lower morbidity. These procedures are intended to result in varying degrees of weight loss and/or improvement of weight-related metabolic comorbidities. The American Society for Gastrointestinal Endoscopy (ASGE) and the American Society for Metabolic and Bariatric Surgery (ASMBS) have created a combined document to promote the safe development and appropriate application of EBTs [6].
The goals of EBTs are to have an impact on obesity and its weight-related comorbidities. However, the threshold by which we measure the efficacy of these procedures should be tailored to the benefit/risk profile and the overall intent of the therapy. The potential indications for EBT include primary therapy (with significant effect on weight loss and similar benefit/risk profile to surgical intervention), early intervention/preemptive obesity (lesser degree of weight loss but emphasis on safety), bridge therapy (an intervention that should allow for lowering the risk of a subsequent intervention), metabolic therapy (inducing objective changes in metabolic parameters), and revisional therapy (augmenting or revising a surgical procedure). Based on the intent of therapy, safety and efficacy are evaluated in conjunction with repeatability, durability, and permanent or nonpermanent alteration of the anatomy [6].
Primary EBT
Primary EBT should result in significant weight loss and improvement in medical comorbidities with a benefit/risk profile similar to bariatric surgery. This treatment modality can be considered in morbidly obese patients as an alternative to conventional procedures and treatments. The resulting excess weight loss should be comparable to a bariatric operation with a similar risk profile. However, a lower efficacy can be acceptable for an EBT if the morbidity is also decreased. This therapy will also need to have a significant long-lasting effect as seen with a surgical intervention. It may be permanent or require repeatability if the durability of the effect is of shorter time period.
Early Intervention/Preemptive Therapy
The goal of early intervention/preemptive therapy is to achieve weight loss in potentially class I obese patients who are at risk of disease development or disease progression. The evidence to support this concept of treatment comes from prospective studies demonstrating significant weight loss and improvement/resolution of weight-related comorbidities in class I obese patients undergoing bariatric surgery (i.e., sleeve gastrectomy and adjustable gastric banding) [7, 8]. More recently, the US Food and Drug Administration (FDA) has approved the use of adjustable gastric banding for class I obese patients with weight-related comorbidities. The benefit/risk profile of an EBT performed as early intervention/preemptive therapy should have a predominant focus on safety. The intent of therapy of this particular EBT may also rest in behavior modification and therefore be applicable to adolescents. The EBT may not necessarily require a permanent alteration in anatomy or have a long-term effect (i.e., less durability).
Bridge Therapy
Morbidly obese patients with a higher body mass index (BMI) are at increased risk. This has been demonstrated in multiple surgical subspecialties including bariatric, orthopedics, cardiovascular, organ transplant, oncology, and many others [9, 10]. The negative impact of obesity is more accentuated in patients with a BMI > 60 [11]. The goal of this class of EBT should be to reduce enough preoperative weight to have a significant impact in the morbidity and mortality profile of a subsequent intervention. Examples may include a reduction in the ASA class or eligibility for organ transplantation. When evaluating the efficacy of this EBT, the durability of the intervention is less important.
Metabolic Therapy
EBTs may have a potential role in class I obese patients with a significant metabolic condition such as type II diabetes, hypertension, and dyslipidemia. Modest weight loss (~5 %) in these patients has shown a significant improvement in cardiovascular risk factors [12]. The efficacy of EBT should be measured by objective metabolic benefits and not necessarily excess weight loss. Procedures used in this patient population should have a lower risk profile and higher durability (or repeatability) than therapies intended for greater weight loss.
Revisional EBTs
As the number of patients undergoing bariatric surgery continues to increase, so will the number of cases requiring revisional procedures. Weight regain or weight recidivism has been cited as the most common indication for revision [5]. A number of endoluminal platforms will provide the tools necessary to perform stoma and pouch reduction after gastric bypass and modifications after other bariatric procedures.
Having now set up the framework of EBTs, the next part of this chapter will evaluate current therapies and report on their results. It is important to understand the limitations of many of these studies including small numbers, no comparators in many, and short-term follow-up. However, at the same time it is important to evaluate these modalities for their technical feasibility and benefit/risk profile. As in any technology, there will continue to be refinements that will allow for greater technical feasibility and potentially a more favorable benefit/risk profile, greater durability, and potential for repeatability.
Endoluminal Techniques Altering Gastric Capacity
Limiting the functional capacity of the stomach has been the goal for a wide variety of bariatric procedures. While many have fallen out of favor, restrictive physiology continues to be the goal of commonly practiced operations such as the gastric band, vertical sleeve gastrectomy, and now even gastric plication. Even though the therapy is altering the stomach’s capacity of a meal, there also is a hormonal alteration produced by these operations and potentially the EBTs [13]. During the last decade, a variety of EBTs have been developed to mimic this effect. These techniques vary from endoscopic suturing and stapling platforms to space occupying devices.
Endoscopic suturing and stapling platforms have been used to create a vertical gastroplasty. The EndoCinch™ (Bard-Davol, Warwick, RI) was the first-generation endoscopic suturing device approved by the Food and Drug Administration. Initial experience with the EndoCinch™ device was reported in the treatment of gastroesophageal reflux disease [14]. The first reported series of endoluminal vertical gastroplasty in managing obesity was reported in 64 patients. The authors employed a single running stitch through 5–7 anchor points. They reported a mean percentage of excess weight loss (%EWL) of 21.1 ± 6.2, 39.6 ± 11.3, and 58.1 ± 58.1 at 1, 3, and 12 months, respectively. However, the range of BMI was from 28 to 60.2 kg/m2. Fifty-nine of 64 patients were followed for 12 months [15]. With some modifications to the device and standardization of technique, a US feasibility study was developed. The TRIM trial was conducted at two centers and enrolled 18 patients. At a 1-year follow-up of the TRIM trial, a %EWL of 27.7 % was reported. There were no serious adverse events related to the device or procedure. In terms of durability, a 12-month EGD surveillance revealed spontaneous suture release in 5/14 subjects and partial release in 8/14 [16, 17].
More recently, transoral gastroplasty was described using an endoscopic stapling device (TOGA® System – Satiety™ Inc. Palo Alto, CA). Early trials had demonstrated the safety and feasibility of this procedure. Durability, however, remained a major concern. In the first study reported by Deviere et al., 11/21 patients were found to have either a proximal or mid-gap along the staple line prior to discharge. At 6 months, only five patients had intact sleeves or staple lines. A later study by Moreno et al. showed better results using a second-generation device. Mean excess weight loss at 6 months ranged from 26.5 to 46 % [18, 19].
The Incisionless Operating Platform (IOP – USGI Medical Inc., San Clemente, CA) is another new generation of endoscopic suturing platforms that is being applied as a primary EBT. The procedure has been called Primary Obesity Surgery Endoscopically (POSE) and features an instrument with larger arms, allowing for the purchase of more tissue within the plication. An animal model was developed to evaluate the feasibility of this EBT. This study recreated the anatomy of a dilated pouch with an enlarged stoma in a porcine model. The authors were able to reduce stoma size by a mean of 11.5 mm in the live animal model and pouch size by a mean of 28 mL in the ex vivo model [20].
The concept of placing an intragastric balloon to restrict oral intake dates back to the mid-1980s. In 1985, the Garren-Edwards gastric bubble was approved by the FDA to be used as an adjunct to diet and behavioral modifications for treatment of obesity [21]. Multiple devices have been developed since then and used worldwide. The BioEnterics Intragastric Balloon System (Inamed. Santa Barbara, CA) has been the most widely studied device. The Italian Collaborative Study Group for Lap Band and BIB (GILB) retrospectively reviewed 2,515 patients that were treated with the BioEnterics balloon for 6 months. They reported a mean %EWL of 33.9 % ± 18.7 % with an overall complication rate of 2.8 % [22]. A new-generation balloon developed by Spatz FGIA Inc. (Jericho, NY) incorporates adjustable volume technology and has been approved outside of the USA for implantation for up to 1 year. ReShape Medical has taken a different approach by developing a dual-balloon implant (ReShape Duo™) that occupies a larger volume (900 mL compared to the typical 500–700 mL balloons). The individual dual-balloon technology prevents unwanted migration in case of deflation of one of the balloons.
The Trans-oral Endoscopic Restrictive Implant System (TERIS – Barosense Inc., Redwood City, CA) is a device that attempts to recreate the effects of a gastric band by implanting an endoluminal prosthesis having a diaphragm configuration within the gastric cardia. Another similar device is the HourGlass (HourGlass Technologies, Redwood City, CA). These devices are still in early stages and no supporting data is available.
Metabolic Endoluminal Procedures
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