Abstract
BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed metabolic and bariatric surgeries (MBS) worldwide due to its simplicity and efficacy. However, long-term outcomes have revealed limitations, including recurrent weight regain, inadequate weight loss, and nutritional deficiencies, leading to an increasing need for revisional bariatric surgery. While revisional procedures can restore weight loss efficacy, they may also carry additional risks of micronutrient and protein deficiencies due to anatomical and physiological alterations. METHODS: This review was conducted in accordance with PRISMA guidelines and included studies published up to April 2025. A systematic search of PubMed, Scopus, Web of Science, and Cochrane Library was performed. Eligible studies reported nutritional outcomes after revisional bariatric procedures following LSG. Data on vitamin D, vitamin B12, iron, calcium, albumin levels, and anemia were extracted. Meta-analyses were conducted for both continuous and categorical outcomes. RESULTS: Fourteen studies with a total of 1,049 patients were included. Deficiencies in key micronutrients such as vitamin D, vitamin B12, albumin, calcium, zinc and iron were reported across revision types. A co-author network analysis was performed to identify and address overlapping cohorts. The analysis revealed notable rates of nutritional deficiencies across all procedures. Vitamin D deficiency was more frequent in certain revision surgeries. Iron deficiency showed statistically significant differences between groups (p = 0.025), with one revision type associated with a higher risk (p = 0.0106). Albumin and anemia rates did not differ significantly between procedures, but anemia remained a common complication overall. CONCLUSION: Micronutrient deficiencies are notably prevalent following revisional bariatric surgery after LSG. Despite the routine use of supplementation regimens, deficiencies in vitamin D, vitamin B12, iron, and protein continue to be frequently reported. Considerable variability among surgical techniques highlights the need for individualized nutritional monitoring and the implementation of standardized supplementation protocols.