Conversion of One-Anastomosis Gastric Bypass (OAGB) Is Rarely Needed if Standard Operative Techniques Are Performed

Mini-gastric bypass (MGB)/One-anastomosis gastric bypass (OAGB) is currently performed by an increasing number of surgeons around the world [2, 3]. Published experiences have escalated in recent years and are positioning MGB/OAGB as a safe and effective alternative in bariatric/metabolic surgery [2‐4]. Although a controversy has arisen in regard to the name of the procedure [5], this should not divert attention and demerit overall outcomes achieved and reported.

The main argument in opposition to MGB/OAGB has been the possibility of bile reflux (BR) and its repercussions. This was critically stated by Johnson et al. [6] in a review from complications managed at different hospitals, whose purpose was to assess (and discredit) the claim that revisional surgery was rarely required in this patient population [7]. This article, however, was full of assumptions, and as previously expressed [8], drawing valid conclusions without a denominator (total number of patients) is impossible. Moreover, no descriptions about operative findings were given, particularly in those cases with “intractable” BR; some may have been similar to the present case [1], which, due to its gastric pouch characteristics, in fact resemble the old (and abandoned) Mason’s loop—see below [9].

BR after MGB/OAGB has been reported to be rare, presenting sporadically after specific triggers, usually at night and subsiding after medical treatment [2, 3, 10‐15]. In addition, BR in these instances has usually been identified clinically and through ancillary studies only in the stomach [10, 12, 16]. Even those highly critical of MGB described “intractable” BR gastritis (and not esophagitis) as the indication to reoperate on their patients [6]. The fact that BR does not reach the esophagus has important implications [17].

Fear of cancer due to BR has also been an issue mainly based on older studies from the time of peptic ulcer surgery. Several of these have been contradictory and did not take into account various confounding variables such as Helicobacter pylori [18]. In any case, even the highly criticized Mason’s loop with its proven BR has not been associated with esophageal cancer, and so far, only one case of gastric pouch cancer has been reported 26 years after [19]. Three other cases of cancer after Mason’s loop have been found; however, these were unrelated to BR as they were in the bypassed stomach; cancer in this location has also been identified after other bariatric operations [20]. The MGB/OAGB concept started ∼20 years ago, and after thousands of operated patients, the only case of cancer reported thus far, also originated in the excluded stomach, is an Asian patient 9 years after MGB [21]. This is in contrast to other bariatric operations in which cancer in the gastric reservoir or esophagus has indeed been reported [20].

Almost a decade after the cited critical paper by Johnson et al. [6], conversions due to “intractable” reflux have rarely been reported; rates range from 0 % (most MGB/OAGB series) to 0.7 % [2, 3, 7, 10‐15, 22]. Furthermore, the fact that “intractability” has seldom been described precisely is noteworthy. During the phases of digestive adaptation to MGB/OAGB, some patients experience dyspeptic symptoms which may be due to transient BR, or could be completely unrelated to it; recognizing and classifying them appropriately may avoid unwarranted stress to both patient and surgeon and elude needless reoperations. If after an appropriate diagnostic approach BR is considered to be the problem, medical treatment must be instituted for a reasonable period of time, as some of these symptoms are temporary.

On the technical standpoint, it is important to clarify BR was frequent and in fact the reason to abandon Mason’s loop [9]. Its short gastric reservoir was based on the fundus and formed after a high horizontal transection. Since bypassed small bowel averaged <80 cm, undiluted biliopancreatic secretion was placed in close proximity to the esophagus and led to intractable symptoms. MGB’s anatomical configuration through its long, narrow, and vertical pouch, which is based on the lesser curvature, makes esophageal BR highly improbable [7]. Our OAGB with its anti-reflux technique and longer segment of bypassed small bowel (Fig. 1) take this procedure a step further [10]. The case reported by Facchiano et al. [1] is illustrative in several ways. They clearly describe endoscopic and operative findings, and identify a rather short pouch as the potential cause of BR. When reoperations due to “intractable” BR have been carried out, such accounts have not always been given [6]; this information is quite valuable and its reporting should be encouraged.

For the very few patients that require a reoperation due to intractable BR, alternatives include Braun entero-enterostomy (EE) and conversion to Roux-en-Y gastric bypass (RYGB) with or without gastric pouch shortening [6, 14, 22]. Precise anatomical details are needed before a decision among these options is taken. Whereas gastric reservoir delineation may be achieved preoperatively (through an upper gastrointestinal swallow and/or endoscopy), information about limb lengths must be obtained intraoperatively. Technically, the easiest alternative is the Braun EE [6, 7, 15]. This was successfully performed by Kular et al. [13] in only one patient (out of 18 with BR) that required a reoperation in their series (0.09 %). Since bile is not completely diverted, a short gastric pouch (such as the one in Facchiano et al. case [1]) would perhaps be a contraindication for this operation. Conversely, an increased incidence of marginal ulcer has been a concern leading some to propose a formal (complete) conversion to RYGB, which is the most cumbersome procedure. In order to restore the digestive tract, it requires anastomotic resection followed by an EE; RYGB is then constructed by pouch shortening and a (regular) 1.5-m-long alimentary limb. This has been done with excellent results at a mean of ∼2 years after OAGB by Chevallier et al. in 7 (0.7 %) patients who also kept their weight loss in their series [14]. A less technically demanding option is conversion to RYGB without resection of the anastomosis and pouch shortening. Division of the afferent loop close to the gastro-enteric anastomosis is followed by an EE to form the alimentary (Roux) limb. This latter measured 50 cm in 3 (0.2 %) patients in the Lee et al. series [22] and 70 cm in 4 (0.4 %) patients in the Noun et al. series [11] and also in the current report of Facchiano et al. [1]. We believe concern in regard to marginal ulcer is unfounded. Its incidence after such reoperations should not be different from that of primary MGB/OAGB whose range is 0.6–4 % [2, 3], and is similar or even lower than that of RYGB [23].