Revisional surgery in severe nutritional complications after bariatric surgical procedures: report of four cases from a single institution and review of the literature

ABSTRACT Introduction: bariatric surgery is currently the only treatment that leads to long-term and sustained weight loss and decreased morbidity and mortality in morbidly obese individuals. Roux-en-Y bypass causes weight loss by restricting food intake associated with reduced intestinal absorption, in addition to multiple endocrine and satiogenic effects. Biliopancreatic diversion promotes weight loss mainly due to poor absorption of the nutrients ingested. Both procedures exclude parts of the gastrointestinal tract. Objective: to describe four cases of revisional surgery after primary bariatric surgery, due to serious nutritional complications, and to review the literature regarding this subject. Methods: a retrospective analysis of patients of Unicamps bariatric center database and review of the literatures were performed. Results: four patients were identified, 2 women and 2 men, with a mean age of 48 years. The mean body mass index before revisional surgery was 23.7 kg/m2. Three patients underwent Scopinaro biliopancreatic diversion, and onde patient underwent Roux-en-Y gastric bypass. The revisional surgeries were revision, conversion, and reversion. One patient died. For the review of the literature 12 articles remained (11 case reports and 1 case series). Another five important original articles were included. Conclusion: fortunately, revision surgery is rarely necessary, but when indicated it has increased morbidity, It can be revision, reverion or conversion according to the severity of the patient and the primary surgery performed.


INTRODUCTION
I n 2016, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 650 million were obese 1 .
Bariatric surgery is currently the only treatment that leads to long-term and sustained weight loss and decreased morbidity and mortality in morbidly obese individuals 2 .
However, lifestyle modifications that include changes in diet and increased physical activity usually result in inefficient weight loss and inadequate maintenance of weight in the long-term 3 .
Roux-en-Y bypass causes weight loss by restricting food intake associated with reduced intestinal absorption, in addition to multiple endocrine and satiogenic effects. Biliopancreatic diversion (BPD) promotes weight loss mainly because of poor absorption of nutrients.
Both procedures exclude parts of the gastrointestinal tract, which cause potential development of metabolic deficiencies and malabsorption of certain nutrients, including proteins and certain minerals and vitamins 4 .
Clinically relevant malabsorption should be considered if a patient shows one or more of the following symptoms/signs after the bariatric surgical procedure: gastrointestinal symptoms/signs, including diarrhea, abdominal distention, flatulence, abdominal pain and ascites, and other general symptoms, such as persistent weight loss, anemia, amenorrhea, impotence, infertility, night blindness, xerophthalmia, peripheral neuropathy, tiredness, fatigue, and weakness 5 . After the malabsorption procedure, a blood test panel must be requested, together with a regular postoperative follow-up, from the preoperative period, then in between the 3 rd and 6 th -month in the first two years, and annually thereafter 6 .
The present study aims to report the clinical aspects and treatment of four patients who underwent revisional surgery after primary bariatric surgery due to serious nutritional complications and to review the literature on this subject.

METHODS
Based on a retrospective analysis of data collected from the medical records in Unicamp's bariatric surgery center database, four cases of malnutrition revisional surgery were reported. The collected variables were age, sex, body mass index (BMI) before revisional surgery, bariatric surgery, and revisional surgery, follow-up before and after revisional surgery, outcomes, and reasons for revision.
Literature published in the last 10 years was reviewed through an online search for MeSH terms "Bariatric surgery" and "Malnutrition" in Medline (via PubMed) and Lilacs (via Bireme). Inclusion criteria were original studies, case reports, or case series of patients who underwent bariatric surgery, developed malnutrition or related conditions, and required revisional surgery.
Articles reporting in vitro or animal studies, articles wherein participant characteristics did not meet the inclusion criteria, abstracts from poster presentations, review articles, and duplicate publications were excluded. Other articles were used for contextualization and discussion.
Finally, four cases are presented from this bariatric center.
Based on a retrospective analysis of data  most often related to protein malabsorption, which is the most serious and potentially fatal side effect 10 .
In addition to postoperative follow-up, monitoring these patients preoperatively is extremely important to identify signs of malnutrition. A study conducted in this bariatric center compared individuals who underwent a preoperative interdisciplinary bariatric surgery program with those who did not. The major outcomes included decreased length of hospital stay, wound dehiscence, wound infection, pulmonary complications, fistulas, pulmonary thromboembolism, sepsis, incisional hernias, reoperations, and mortality 11 .
No randomized studies have evaluated the best revisional approach, and a consensus has not been

CONCLUSION
Severe malnutrition after bariatric surgery requiring surgical intervention is uncommon, but when present, it is associated with high mortality that is not negligible. Therefore, bariatric surgeons must be prepared to manage these difficult cases.
After bariatric surgery, patients should be assessed nutritionally on a regular basis. Malnutrition cases can be manifested in a drastic way, such as chronic diarrhea, acute renal failure, liver failure. Revision surgery is rarely necessary, but when indicated it is associated with increased morbidity. The revision procedure can be revision, reversion or conversion according to the severity of the patient and the primary performed operation.