SG is an effective operative method for inducing weight loss. SG may be used as a single operation, or in the case of insufficient weight loss, it can be suggested as a second operation, such as RYGBP or DS. Additionally, SG can be performed as the first step of a two-stage procedure for high-risk patients to reduce the perioperative risks of DS or RYGBP.
An analysis of the literature shows the benefits of LSG compared to laparoscopic gastric banding (LAGB) and laparoscopic RYGBP. There are several technical advantages of SG: nonresection of the pylorus, which prevents dumping syndrome; no intestinal anastomoses and, consequently, no insufficiencies of anastomoses; nearly regular intestinal absorption and a lower risk of developing an internal hernia [11
]. Due to high complication rate of SG procedure is still in discussion. particulary short-term complications as leakage and staple line insufficiency influence the complication rate. In the literature an increasing long-term complication rate is reported to be due to stenosis, gastroesophageal reflux, and reoperation rate due to insufficient weight loss, regain of weight or insufficient amelioration of comorbidities [12
]. Evidence-based data on nutrient deficiencies, especially vitamin B12 and iron, after SG is not available.
RYGBP and BPD are the most effective, but also the riskiest, bariatric methods. Both procedures tend to increase the risk of perioperative complications based on the difficult technical circumstances surrounding the patients' weight and the associated comorbidities, such as hypertension, diabetes, and sleep apnea. The complication rates for super-super obese patients are 23% for RYGBP and 38% for DS. The mortality after RYGBP is 0.5% and 1.0% after DS [13
]. SG, however, reduces perioperative risks of morbidly obese patients with BMI above 60 as a first step procedure.
The reported initial weight loss after SG spans a wide range, between 33 and 83% [14
]. In a prospective study of 100 patients, Johnston et al. presented a %EWL of 60% after 5 years [16
That study group achieved a %EWL of 59.1% after 12 months and 63.8% after 24 months.
Over a 24-month period, the entire patient population experienced continuous weight loss up to the 18th month. After 24 months a weight loss to a BMI of 35.4
kg/m² was achieved. SG as a single operation is suitable for patients with BMIs <50
kg/m². Only 10.3% of these patients (3/29) required a second intervention to induce further weight loss within the follow-up period (versus 41.5% with BMIs ≥50
After 24 months, patients who only underwent SG with BMIs between 35 and 39.9
kg/m² achieved the highest %EWL. Therefore, there was no correlation between the resected volume of the stomach and the %EWL. Only one patient (16.7%) needed to undergo a second operation for further weight loss.
After 18 months, patients who only underwent SG demonstrated increased mean weights, which may have been due to sleeve dilatation. This possibility was considered by Gluck et al., who presented %EWLs of 67.9% after 1 year, 62.4% after 2 years, and 62.2% after 3 years for patients after SG with preoperative BMIs between 35 and 43
There is not always sufficient weight loss after SG; insufficient changes in food patterns or potential recidivism to old food patterns may cause a sleeve dilatation. One option for treatment may be a resleeve operation. There are inadequate data to properly appraise this option, and further studies must clarify the utility of this procedure in comparison to RYGBP or DS as a second operation.
In addition because of the moderate rate of major complications of 9.8% (8/82), SG can be recommended as a first-step operation before malabsorptive interventions. Regarding postoperative complications, there were no significant differences among the BMI categories. However, patients with BMIs ≥60
kg/m² required a change to laparotomy significantly more often because of an insufficient intraabdominal view. Preoperative implantation of a gastric balloon to reduce morbidity for patients with BMIs over 60
kg/m² still needs to be addressed.
In this study, there was a 30-day mortality of 0.0%, a hospitalization mortality of 1.2%, and a one-year mortality of 2.4%.
There were 2 patients who did not benefit from SG. One patient with a preoperative BMI of 50.5
kg/m² first lost weight after SG, but his weight eventually increased to a higher level than before SG (59.7
kg/m² by the end of the followup). An insufficient change in food patterns and intake of high-calorie foods appeared to be the cause. The other patient, with a preoperative BMI of 55.5
kg/m², died after a prolonged course with various complications on day 73 after SG.
One other severe obese patient with a preoperative BMI of 68.0
kg/m² died 10 months postoperatively. A causal relationship with SG was excluded after consultation with the family doctor.
The definitive success rate for SG in this study was 97.6%, with a mortality of 1.2% and a nonresponder rate of 1.2%.
Twenty-five patients (30.5%) in this study required a second operation via a two-stage procedure for further weight loss.
Nutritional deficits after LSG are rarely evaluated. In postoperative course there is no suggestion for vitamin supplementation. Evidence-based data on necessity of supplementation after SG does not exist in the literature. After evaluating nutritional deficiencies, there is no need for supplementation after SG, although preoperative existing deficits should be supplemented. Laboratory parameters should be monitored regularly to detect early nutritional deficiencies and to initiate appropriate therapies.
Vitamin B12 levels were in the lower third of the reference range without supplementation. Therefore, it is likely that, without supplementation, vitamin B12 deficiencies can occur, especially more than two years after operation due to empting of vitamin B12 storage. Therefore, a general vitamin B12 supplementation is advisable to avoid pernicious anemia and to prevent neuropathic pain.
Patients with deficiencies in albumin, vitamin D, or calcium have a higher risk of developing osteoporosis; therefore, it is recommended that appropriate supplementations be initiated, even if the concentrations of these parameters are only slightly decreased. PTH levels should be determined to diagnose secondary hyperparathyroidism.
Based on to parameters, iron supplementation should be initiated similar to the supplementation of folic acid. Moreover, supplementation of zinc should be based on symptoms (hair loss, immune deficiency, dry skin). High zinc intake reduces absorption of copper and iron and vice versa. Medication of zinc and calcium should be suggested to intake at different times, because zinc reduces calcium absorption. Supplementation of selenium is not generally necessary because postoperative deficiencies normalize on their own without supplementation, and an adequate, varied food intake seems to be sufficient.
Regular determination of laboratory parameters should be performed 3 and 6 months after the operation and semiannually thereafter; if the patient's weight stabilizes, laboratory parameters should be determined once a year.