SG is an effective operative method for inducing weight loss. 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.
Literature shows the benefits of LSG compared to laparoscopic gastric banding (LAGB) and laparoscopic RYGBP. Advantages of SG are non-resection of the pylorus, which prevents dumping syndrome; no intestinal anastomoses, no risk of developing an internal hernia and nearly regular intestinal absorption. Complication rate of SG procedure is still high, especially short term complications as leakage and staple line insufficiency influences the complication rate. In literature an increasing long term complication rate is reported due to stenosis, gastroesophageal reflux and re-operation rate due insufficient weight loss, regain of weight or insufficient amelioration of comorbidities. Evidence based data on nutrient deficiencies, especially vitamin B12 and iron, after SG is not available.
SG, however, reduces perioperative risks of morbidly obese patients with BMI > 60 kg/m2 as a first step procedure. The reported initial weight loss after SG spans a wide range, between 33 and 83 %.[13,14] In a prospective study of 100 patients, Johnston et al. presented a %EWL of 60 % after 5 years. That study group achieved a %EWL of 60.3 % after 12 months and 63.8 % after 24 months.
Over a 24-month period, the entire patient population experienced continuous weight loss. The weight loss remained constant (BMI 35.4 kg/m2) in clinical examinations through the 24th months. SG as a single step operation is suitable for patients with BMIs < 50 kg/m2. Only 8.1 % of these patients (3/37) required a second intervention to induce further weight loss within the follow-up period (vs. 34.9 % with BMI of 50 kg/m2). After 24 months, patients with a BMI between 35 to 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 (12.5 %) 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 kg/m2.
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 re-sleeve 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 8.0 % (8/100), 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 BMI > 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 BMI > 60 kg/m2 still needs to be addressed. Especially in patients with BMI above 60 kg/m2 general complication rate is increasing, due to the fact of an increased pulmonary complication risk, longer operation time and a higher risk for renal complications especially rhabdomyolysis.
In this study, there was a 30-day mortality of 0.0 %, a hospitalization mortality of 1.0 %, and a one-year mortality of 2.0 %. 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 follow-up). 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 multimorbid 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 98.0 %, with a mortality of 1.0 % and a non-responder rate of 1.0 %. Twenty-five percent of the patients 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 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 during supplementation. Therefore, it is likely that without supplementation, vitamin B12 deficiencies would have occurred. 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). 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 6 months after the operation and semiannually thereafter; if the patient's weight stabilizes, laboratory parameters should be determined once a year.
BMC Surg. 2012;12(13) © 2012 BioMed Central, Ltd.
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