Martin Van Wezenbeek

DISCUSSION

As stated in the introduction, bariatric surgery is the best therapeutic option for the treatment of morbid obesity in terms of weight loss and a reduction of obesity-related comorbidities, while reducing the lifetime health care costs and 1-4 elevating the postoperative quality of life. Although the majority of bariatric patients benefit from these positive outcomes, a small but significant amount of patients is confronted with some type of complication. The aim of this thesis was to contribute to the reduction of before mentioned complications by analyzing current results of revisional surgery, finding predictors for complications and assessing the effect of different intra-operative techniques.

Part one

To develop a notion on treating complications in the future, it is essential to have a proper understanding of the past. Therefore, Chapter 1 described the long-term outcome of primary vertical banded gastroplasty (VBG) in 392 patients. With a mean follow-up of 66 months, VBG provided an acceptable mean excess weight loss of 53%, with a 55% improvement of obesity-related comorbidities. Nonetheless, this chapter underlined the major disadvantage of this procedure, with a reported complaint rate of 58% and a total revision rate of nearly 40%. These numbers are similar to previously reported statistics and 5-9 strengthen the believe to abandon this old restrictive bariatric procedure. Nowadays, sleeve gastrectomy appears more suitable, as the first reported 10 results are superior to those of the VBG. Even though VBG is abandoned in the Netherlands, an interest should be taken in its anatomical similarities with the more modern banded gastric bypass. The main difference between the two procedures is the presence or absence of the pyloric valve. The results of the older VBG may be helpful in improving the banded gastric bypass, as literature is already reporting a complication rate up 11 to 20%.

It is becoming more and more clear that the success of bariatric also depends on many psychological factors such as eating behavior. Chapter 2 attempted to find more of these predictors for success or failure. Among others, it identified that successful patients depend less on the procedure than patients who failed. This supports the results presented by Mitchell et al. that proper lifestyle changes may be more important than the bariatric procedure itself for 13 achieving sufficient long-term weight loss. This chapter showed a few other potential predictors. Unfortunately, the outcome of this study does not provide the solution for a standard pre- and postoperative psychological evaluation. On the contrary, psychological guidance before and after bariatric surgery needs to be individualized, while keeping track of the major (psychosocial) risk factors associated with failure. Unfortunately, the conclusion remains similar to the majority of other psychological bariatric publications: more (high quality) research is highly needed and current results are inconsistent. 13-17

After developing an understanding of the primary VBG, the next task was understanding its revisional procedures. Chapter 3 described the results of different revisional procedures after primary failed VBG. Even though the groups in this study were skewed and some of the groups were small, the results were still very clear. The best revisional option after failed VBG is a Roux-en-Y gastric bypass (RYGB) when compared to revision of the VBG or conversion to a sleeve gastrectomy. This study proved a superiority for conversion to RYGB in terms of (additional) weight loss, improvement of obesity-related comorbidities, the occurrence of long-term complaints or complications and the need for additional revisional surgery. Revision of the VBG or conversion to sleeve gastrectomy should be not be considered as revisional option for failed primary VBG based on these results. These statements are supported by other studies on this subject. 9,18-20 Therefore, if revision of a failed primary VBG is indicated, it is suggested to only perform a revision to RYGB unless this is technically not possible.

As shown in Chapter 3, RYGB appears to be a feasible and effective option as revisional procedure after VBG. Can this statement be extended to other restrictive procedures such as the adjustable gastric banding (AGB)? The suggestion is supported by previously published literature, which shows good results of RYGB as revision after failed AGB. Furthermore, conversion to RYGB appears to be superior after failed AGB when compared to band revision or conversion to sleeve gastrectomy. 21-24 A drawback is a high postoperative complication rate after revision, as a gastric pouch is created around the old location of the AGB. 24, 4 hypothesized that the complication rate may be lower when converting a failed sleeve gastrectomy to RYGB. The thought behind this hypothesis was to further strengthen the believe that AGB should be abandoned as a primary bariatric procedure, besides the high long-term failure rate of this procedure. 23,26,27 Furthermore, this study investigated the effectiveness of RYGB as revisional procedure after either failed AGB or sleeve gastrectomy (SG). The results did not support the believe that conversion to RYGB after sleeve is a safer procedure when compared to RYGB after failed AGB as it reported a similar postoperative complication rate (8.8% vs. 11.8%; p=0.530). Although these results suggested a similar effectiveness of RYGB as revisional procedure after either AGB or SG, they should be interpreted with caution. During follow-up, a slight decrease in total weight loss was observed in the SG group compared to an increase in the AGB group. The results in this chapter confirmed that RYGB is a valuable option as revisional procedure after failed AGB, however, it cannot be irrefutably stated that it is as valuable after failed sleeve gastrectomy for achieving additional weight loss. Keeping the high failure rate of the AGB and the high complication rate after revision in mind, AGB should not be performed routinely as a primary bariatric procedure until reliable selection criteria are developed. 23,26-28 Nowadays, both SG and RYGB are considered longer lasting and safer bariatric procedures. 29-31

Recently, fast track protocols were introduced to counterattack the increasing demand for bariatric surgery and have proven to be safe and effective. 32,33 It is expected that many revisional procedures will be performed over the next years when considering the amount of performed VBG’s, AGB’s and SG’s in the last decades. With the increasing demand for revisional surgery, the question rises whether fast track surgery would be safe in this challenging group of patients. The main goal would be to stabilize or even decrease the significant complication rate. Despite being comparable with previous literature, Chapter 3 and 4 reported a high complication rate between 8-13%. 34- 5 reported on the results of the use of a fast track protocol in revisional bariatric surgery. This study reported a significant decrease of the postoperative complication rate after implementing the fast track protocol. Based on these results, fast track care is safe to implement in bariatric revisional surgery, potentially reducing health care costs by lowering hospital stay and increasing logistics without increasing the complication rate. 32,33 Even though a significantly lower complication rate is reported (19.2% vs. 11.2%; p=0.038), caution should be taken in assuming that fast track care decreases the complication rate. Strong confounding factors such as an increased experience of the operating team, the surgeon’s learning curve or improved surgical equipment may also be the cause of the reduced complication rate over the years. 39,40

When aiming for relief of reflux complaints, RYGB appears to be effective, but the value of RYGB as revision after failed sleeve gastrectomy to achieve 41 additional weight loss, is debatable. Casillas et al. reported similar results as shown in Chapter 4, which is a decline in (additional) weight loss over time after 42 RYGB as revisional for failed primary sleeve gastrectomy. Yorke et al. reported on the lowest BMI after revision of primary sleeve gastrectomy to RYGB. A mean BMI of 36.4 kg/m is reported. Despite the fact that this is lower than the reported BMI after primary sleeve gastrectomy, this is well within range to be 43 called morbid obesity. Even though some studies do report good results on RYGB as revisional procedure after failed primary SG, the search for a potentially better alternative has started. Homan et al. and Carmeli et al. have explored the potentials of the biliopancreatic diversion compared with Roux-en-Y gastric bypass. Even though a higher weight loss is reported, a drawback is that this type of procedure is technically more challenging and may lead to an even higher rate of postoperative complications. 44,45 Therefore, the single-anastomosis duodenoileal bypass (SADI) was chosen to investigate as an alternative for RYGB after sleeve gastrectomy in Chapter 6. Even though the knowledge on this relatively new procedure is limited, the first results seem promising. 46,47 After 12 months, this study showed a slightly higher weight loss and less early postoperative complications in the SADI group, which were not significantly different when compared to the RYGB group. Biggest drawbacks were the limited group sizes and the total follow-up. Based on these limited results, SADI appears to be safer compared to a biliopancreatic diversion in terms of postoperative complications.

Recent studies do support the hypothesis that SADI is a valuable alternative to achieve additional weight loss after sleeve gastrectomy. 48-50 The biggest drawback of these results are the retrospective nature of the studies. Good prospective, preferably randomized controlled trials are necessary to place current results into perspective. With the current knowledge of the SADI and the results from Chapter 6 in mind, Chapter 7 reported on a study protocol for a prospective, randomized controlled trial.

Part two

As mentioned before, part two of this thesis focused on postoperative complications after bariatric surgery. Obviously, prevention is the best way to lower the postoperative complication rate. Prevention is based on knowing the risk factors. Chapter 8 reported on predicting factors for the occurrence of major complications (Clavien-Dindo ≥3a) after primary RYGB. Even though the study population was small (only 773 patients), this study identified two independent risk factors: male gender and chronic obstructive pulmonary disease. It seems unlikely that the male gender itself is a risk factor for the occurrence of postoperative complications, however, the male bariatric population are more often diagnosed with metabolic syndrome. This in turn is correlated to an increased risk at postoperative complications in bariatric surgery. Is it an option to stabilize or even treat this syndrome before performing bariatric surgery so the postoperative complication rate may be lowered? Recent