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SASI bypass safe but concerns over potential of malnutrition and excessive weight loss

Single anastomosis sleeve ileal (SASI) bypass appears to be an effective procedure for the treatment of morbid obesity and its related comorbidities however, it is important to note that protein malnutrition and excessive weight loss are potential complications that may require further surgical intervention, according to researchers from Helwan University, Helwan, Egypt. The findings were reported in the paper, ‘Unpredictable Malnutrition and Short-Term Outcomes after Single Anastomosis Sleeve Ileal (SASI) Bypass in Obese Patients’, published in the Journal of Obesity.

Figure 1: Hand-sewn anastomosis of the stomach and jejunum (Credit: Journal of Obesity)

The researchers said the study sought to evaluate the feasibility and efficacy of the SASI technique in 30 patients with morbid obesity who underwent SASI bypass at their centre from March 2019 to March 2020. The average BMI was 47.3 ± 7.6 kg/m2 and patients were morbidly obese for an average of 24 years.

During the surgery, dissection was started on the greater curvature, 5cm from the pylorus up to the cardio-oesophageal junction until full mobilisation of the gastric fundus was achieved. Once the greater curvature was liberated, a 36-French orogastric tube was inserted into the stomach and duodenum. The stomach was resected using endo-GIA linear staplers that were applied parallelly to the lesser curvature, starting from 3 to 5cm from the pylorus and extending up to the angle of Hiss.

After the creation of the sleeved gastric tube the transverse mesocolon was pulled towards the head of the patient and 250cm of the ileum was measured from the ileocecal junction. A 4cm antecolic side-to-side gastrojejunostomy was then performed at the anterior wall of the area between the antrum and the body of the stomach using hand-sewn PDS 2/0 sutures (Figure 1). Full intestinal measurements were not performed. A leak test was performed by injecting 50–100 cc of methylene blue. The resected stomach was removed through the left midclavicular port, and the procedure was completed with a gastric tube having two outlets: one to the duodenum and the other to the ileum. Drains were left in place for 24 hours.

The researchers followed patients in the outpatient clinic (OPC) on a weekly basis during the first month after their surgery for an early detection of any postoperative complications, such as fever, collection, bleeding, or leakage. Subsequently, they were followed up at two, six and 12 months after surgery to evaluate surgical outcomes such as BMI, fasting blood sugar, lipid profile, and indicators of nutritional complications such as plasma levels of albumin, haemoglobin,and calcium. During the 12 months of follow-up, micromalnutrition was assessed by vitamin D levels less than 30 ng/mL, while macromalnutrition was assessed by hemoglobin levels less than 10 g/dL or albumin levels less than 3.5 g/dL.


They reported that the most significant comorbidity was hyperlipidaemia (in approximately two-thirds of the studied patients (70%)), followed by type 2 diabetes mellitus (63.3% ) and hypertension (40%). Symptomatic gallstones were identified in 10% of the studied patients (3 patients), whilst gastroesophageal reflux disease was found in 26.7% of the cases (8 patients). Hypertension, GERD, and DM were completely cured with highly statistically significant differences, with values of ≤0.001, ≤0.001, and ≤0.005, respectively. One patient developed new-onset GERD postoperatively, which was managed with cruroplasty and gastric bypass due to concurrent macromalnutrition.

Malnutrition was identified in 19 patients (63%), with 3 cases of micromalnutrition which improved with medical management and nutritionists, while 16 cases had macromalnutrition, in which one case improved with medical management and nutritionists and the other 15 patients (50%) required revision. Six patients (20%) had steatorrhea, which was managed by nutritionists. The majority of patients (70%) experienced food intolerance, primarily severe protein intolerance, with 6 cases improving with dietary interventions, and the remaining cases requiring reoperation due to macromalnutrition. Male patients and those with longer duration of obesity had significantly higher rates of revision and malnutrition (p≤0.001).

The authors stated that the study provides insight into the safety and effectiveness of primary SASI bypass in morbidly obese patients, particularly those with poor nutritional habits that may hinder weight loss or lead to weight regain after a restrictive bariatric procedure such as SG. However, although the SASI bypass has been accepted as a standard procedure by the expert bariatric surgical consensus panel in 2018, its lack of approval by IFSO highlights the need for continued evaluation and discussion of this procedure.

“To minimise these risks (malnutrition and excessive weight loss), continuous refinement of the technique is necessary and special consideration should be given to patients with longer exposure to obesity, especially males,” the authors concluded. “In addition, it is worth noting that SASI bypass can be easily reversed to a sleeve gastrectomy if needed. Nonetheless, further studies are needed to fully evaluate the long-term outcomes and potential risks associated with this procedure.”

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