Obesity can be treated conservatively (diet, medications, physical activity) or surgically. Lack of permanent outcome of the conservative treatment is presented in figure 1 (1).

Such discouragingly poor results of the conservative treatment of obesity resulted in the development of surgical techniques in the second half of the 20th century. An increase in the number of surgically treated obesity cases in the US confirms this fact. Figure 2 shows how much the number of surgical procedures in the US has increased recently (2).

Of note is the fact that in 2006 the number of surgical procedures for obesity treatment in the US exceeded 171,000 and was higher than the number of cholecystectomies.

What do we expect from the surgical treatment of obesity? The surgical treatment can be acceptable if it meets the following conditions:

It will result in a considerable and permanent decrease in body mass (60-80% of overweight);

It will make co-morbidities regress or alleviate them substantially;

It will affect the quality of life including the possibility to go back to work;

The perioperative complication and mortality rates will be acceptable.

One of the objectives of surgical obesity treatment is body mass loss. The treatment is considered effective if at least 50% excess weight loss (EWL) is achieved. Following different types of surgery, this parameter varies; it is also more or less permanent. Mean EWL at 12 months after laparoscopic procedures is for DS-BPD 70-80%, for G-B 77%, for AGB 69% (3, 4). These data prove that the most extensive procedures, i.e. with potentially the highest risk for complications, result in the highest body mass loss (fig. 3).

Yet, many studies also report that such surgery causes the biggest metabolic disturbances in the form of deficiency syndromes. A patient after surgical obesity treatment loses weight. But is this weight loss permanent? Or sufficiently long? Today, when the follow-ups have been long enough, we can say it is. Patients with a low-pressure adjustable gastric band lose weight regardless of their BMI before surgery (from 35 to more than 60 kg/m²), age or sex, and the corrected body mass is maintained for many years with only minor modifications at 12 months after surgery (5).

When qualifying a patient for an appropriate type of surgery the parameters which must be considered are: the past highest and present body mass, co-morbidities, and the patient´s compliance in each stage of treatment. This should make the surgical procedure bring expected and permanent results with the smallest risk for the patient.

Does the type of surgery affect the weight loss in the postoperative period? Many authors believe that the type and outcome of surgery cannot be associated with the body mass loss expressed in EWL.

The analysis of the type of surgery performed (weight loss has been reported in literature) shows that what Scopinaro introduced in 1976, i.e. biliopancreatic diversion (BPD) and duodenal switch (DS), lead to the greatest excess weight loss, in the range 65-75%, which is permanent. The fact has been confirmed by studies performed by Hess and Hess, Marceu et al. and many others (acc. 6,7). After reviewing the relevant world literature.

Neugebauer et al. designed guidelines for treating obesity for EAES and published them in 2007 (7). In the study mentioned above, the authors reported the following results. In the comparison of RYGN with VBG, a randomized trial carried out by Sugerman showed that EWL was higher after RYGB (68% vs 43%) but absorption disorders, vomiting and gastroenterostomy stenosis were more common after RYGB. These facts were confirmed by the studies performed by Hal et al., Howard et al., and Mac Lean et al. Randomized studies carried out by Nussel et al., which compared VBG with ASGB in open surgery with LASGB done by Morino et al., revealed that at 5 years EWL was similar in all patients. Rabkin et al. and Murr et al. compared BPD with RYGB and reported EWL to have dropped more after BPD (78 and 74%) than after RYGB (71 and 57%). Yet in a trial by Deveney et al., EWL decrease was similar in both groups. Bjardi et al. found EWL to have dropped more after LRYGB in comparison with LASGB – 64% vs 48%. Miller and Hell reported that at 12 months after laparoscopic surgery, EWL drop for DS-BPD was 70-80%, for LRYGB 77%, and for LASGB 69% (acc 6,7).

Pa?nik assessed EWL rate after restrictive surgery and found the highest weight loss after vertical banded gastroplasty (67%), smaller after LASGB (57%). Overall, 84% of his outcomes were good; a better outcome was observed in patients with BMI<50 (8).

Kwiatkowski assessed EWL rate at 12 months after various types of surgery and reported the weight loss as 77.5% after VBG and 60.8% after LASGB. A detailed analysis of the groups studied showed that after LASGB almost 20% failed to reach a 50% EWL, whereas in the VBG group, it was 5%, and in the LRYGB group, all patients exceeded 50% EWL (9).

A literature analysis proves that the highest body mass loss can be achieved after procedures in the following descending sequence: BPD-DS, RYGB, VBG, SG; after ASGB the weight loss is the smallest. The procedures which result in the biggest weight loss are the most difficult technically, need a long learning curve and are associated with the highest risk for such complications as bleeding and leakage as well as deficiency syndromes (vitamin deficiency, especially vitamin B, and microelements). The deficiency resulting from restrictive surgery is easy to supplement if patients are routinely monitored and supplemented accordingly. Such procedures as BPD-DS, RYGB and SG require more staple magazines and that makes them less cost-effective (acc. 6, 7).

Co-morbidities caused by obesity or accompanied by it include type 2 diabetes, arterial hypertension, coronary artery disease, lipid metabolism disorders, diseases caused by osteoarticular system overload, young women´s infertility, and others. Long studies on large groups of patients have proved that, in comparison to people with normal parameters, high BMI, waist circumference and body fat tissue percentage significantly influence the development of co-morbidities.

An important aspect of surgical obesity treatment is the resolution of co-morbidities. Following surgery, type 2 diabetes was found to subside in 74%, arterial hypertension in 57%, manifestations of gastroesophageal reflux in 55%, dyslipidaemia in 38%; EWL at 6 months was 30%, at 12 months 41%, and at 24 months 41%. Many studies do not show any difference or prove the differences insignificant in terms of resolution of co-morbidities depending on the type of surgery (7, 8, 9). Clegg et al. found diabetes to subside in 74% of patients, hypertension in 57%, manifestations of gastroesophageal reflux in 55%, dyslipidaemia in 38% (10). According to Kwiatkowski, Brolin et al. found that co-morbidities subsided or improved in 95% of patients who had undergone surgical obesity treatment. Gordon and Kannel reported NT, dyslipidaemia and carbohydrate disturbances resolution in over 50%, and significant improvement in 24% at 12 months following surgery. Three years after bariatric surgery (VBG, LASGB), Hell and Miller found that co-morbidities had improved or resolved completely in more than 80% of surgical patients. Alvarez et al. found that arterial hypertension had subsided in 90% of patients, and 60% of them could discontinue hypoglycaemic therapy (acc. 6, 7, 8, 9).

In Polish studies, Pa?nik compared the outcome of vertical banded gastroplasty and adjustable gastric band restrictive surgery procedures and found diabetes to have subsided in 28% and improved in a further 44%. Arterial hypertension was found to have subsided in 31% and improved in 44% of patients. He found no significant relevant differences between the types of surgery (8).

Kwiatkowski (9) analyzed metabolic syndrome (MS) improvement after various bariatric surgical procedures and found that MS subsided in 44.5% of patients with BMI below 50; in those with BMI above 50, it subsided in 79.4%. A similar beneficial phenomenon is observed over patients´ age.

Although MS subsided in 50% of patients aged below 50 years, it subsided in 72% of those older than 50. One year after surgical obesity treatment procedures, the metabolic syndrome prevalence decreased from 53% to below 16%. When types of surgery were analyzed, LRYGB was found to decrease MS in 67.2%, LASGB in 54.6% and VGB in 63%. Arterial hypertension decreased from 54.6% to 16.4% at 12 months after surgery. When the type of surgery and persistent hypertension were analyzed, hypertension was present in 7.5% of patients after LASGB, 20% after VGB and 26% after LRYGB. MS subsided in 63-75% regardless of the type of surgery but in the case of arterial hypertension, the most effective was the simplest procedure, i.e. LASGB, and the least effective was LRYGB. Following surgery, diabetes improved from 39.5% to 21.7%. Glycaemia subsidence, depending on the type of surgery, was 39% after VBG, 50% after LRYFB, 66.7.5 after LASGB. Hypertriglyceridaemia before surgery was diagnosed in 39.5% and at 12 months after surgery in 13.5%, so it subsided in 65% of patients who underwent surgery. The best outcome at 12 months after surgery was observed after VBG (71.9%), after LRYGB (64.3%), and after LASGB (56.2%). HDL cholesterol fraction was lowered in 40% of obese patients before surgery, and in only 8.5% at 12 months after surgery. The best outcome was achieved in the LRYGB group (88.9%), in the VGB group (80%), and in the LASGB group (66.7%). MS prevalence analysis proved to be BMI dependent. In patients with BMI<50, MS improved: after LASGB from 26.5% to 2.0%, after VBG from 56.7% to 13.3%; after LRYGB an improvement was observed in all surgical patients. In the excessive obesity group, with BMI>50, MS improved in the LASGB group from 75% to 25%, in the VGB group from 70% to 50%, and in the LRYGB group from 86.6% to 26.7%. When MS prevalence was analyzed in terms of surgery type, patients´ age and sex, no relations between MS improvement and these parameters were found (9).

When obesity treatment outcome is assessed, the assessment should include body mass loss, improvement in co-morbidities but also changes in the quality of life. The outcome is greatly influenced by surgery-induced complications (both short- and long-term) and, first of all, perioperative mortality (complications resulting from surgical obesity treatment are discussed in another paper). Just as important is the aesthetic effect of body mass reduction in the form of excessive skin, post-operative scars and others (10, 11). The results that are reported by physicians treating obesity conservatively and those published from surgical trials are very discrepant. They highlight perioperative mortality and surgery-related complications. Simultaneously, they reveal a completely different approach to the surgical treatment of obesity. This particularly concerns the choice of the moment a surgical procedure should be carried out. Unfortunately, physicians still commonly believe that the surgical procedure is an extreme. Surgeons argue that the surgical procedure should be undertaken when two attempts of comprehensive conservative treatment have failed or when BMI exceeds 40 because such patients will not succeed in achieving a permanent result using conservative methods only (12).

Women who decide to be treated surgically expect to gain a slim figure, which is considered today an ideal of feminine beauty so promoted by the media. For men, on the other hand, it is more important to be physically fit and able to work. A surgeon is mainly interested in the health effect of surgery translated into patients´ body mass loss, improvement in co-morbidities and quality of life. The cosmetic effect of surgery is very important for surgeons too but usually it is not their foremost objective. Modern cosmetic surgery has very much to offer in this field. Besides, surgical procedures should produce very few complications, cause very few postoperative deaths and yield permanent, or at least long-term, good effects (13, 14).

The perioperative mortality rate depends on the type of surgery and ranges between 0.1% and 1%. The lowest mortality rate is associated with gastric banded surgery, but it increases with such comprehensive procedures as gastric bypass or biliopancreatic diversion. Perioperative mortality has been proved to be influenced by the number of surgical procedures performed in a given centre.

Where the yearly number of procedures is small, the mortality rate is relatively high (1.1%); in centres with a medium number of procedures it is 0.4%, to drop to 0.2% in centres where the annual number of procedures is the highest. In a 10-year follow-up, the mortality rate was 6.1%. The mortality rate within 30 or 90 days from surgery refers to the procedure itself, but mortality rates during a 10-year follow-up refer to the group of patients who underwent surgery and results from deaths caused by the surgery, but also by neoplastic diseases, heart diseases or endocrine or metabolic disorders. The paper is particularly valuable because of a very long follow-up covering the years 1980-2005. When a group of obese patients who underwent surgical obesity treatment was compared with a group of obese people who did not, in a 5-year follow-up the mortality rate in the former group was 0.68%, in the latter (not operated) 6.17%. The conclusion from these data is that the surgical obesity treatment improves the 5-year survival rate by 89% (14, 15).

When the causes of deaths of obese people, both operated and unoperated, were analyzed, the frequencies and causes of these deaths turned out to be significantly different. In the operated patient group, the causes of death included:cardiovascular diseases (4.7%), neoplastic diseases (2.0%), and endocrine diseases (9.5%). Among obese people who did not undergo surgical treatment,the causes of death included: cardiovascular diseases (26.7%), neoplastic diseases (8.5%), and endocrine diseases (27.3%). These studies confirm that the mortality rate due to the diseases mentioned above was 3 to 5 times higher in unoperated patients than in operated ones. The conclusion is that the life expectancy of a 40-year-old woman with BMI of 40 kg/m², who undergoes a gastric bypass procedure, will be prolonged by 2.6 years (from 36.2 to 38.8) (14, 15).

Americans studied the impact of the RYGB procedure on the long-term mortality rates in a group of operated patients and compared them with a group of obese people who did not undergo surgical obesity treatment. The study was based on comparable groups of almost 8000 patients in a 7.1-year follow-up. The analysis showed that the mortality rate in the operated group was 40% smaller (37.6 vs 57.1 deaths per 10,000 patients per year of follow-up; P<0.001), and the greatest mortality rate decrease resulted from a drop by 92% of diabetes-induced mortality and a 56% decrease in mortality due to coronary artery disease and other heart diseases. But large, more radical, surgical procedures result in a higher number of complications (15, 16, 17, 18).

Similarly, no significant differences in the costs of particular procedures were demonstrated. The mean cost of such a procedure in the UK is around Ł11,000, and the differences between particular procedures are insignificant. The data were compared with the Cost per Quality-Adjusted Life Years (QALYs) model (5, 10).

In Polish conditions, such procedures as RYGB, BPD-DS, SG, which need a few staple magazines to complete, are much more expensive than gastric banding or procedures which do not need staples. Unfortunately, the National Health Fund pricing regulations do not include these differences.

An interesting aspect of the analysis of the surgical obesity treatment outcome is how the learning curve and experience of the operating surgeon influence the outcome of the treatment including mortality and complications. John Angstadt presented a new programme of pre-, intra- and postoperative proceedings whose aim was to improve the outcome of surgical obesity treatment. The programme included a restrictive antithrombotic policy, antibiotic prophylaxis, appropriate teaching and training for operating surgeons, and an attempt to make each surgeon perform over 70 bariatric procedures per year.

The most important factor found to contribute to outcome improvement was the number of surgical procedures performed yearly. If it exceeded 70, the outcome was significantly better than in the case of other surgeons who operated less frequently. Other factors analyzed did not significantly influence the rate of surgical treatment complications (18, 19).

A very interesting observation comes from R. Gonzalez, who investigated the association between the number of procedures performed and the leakage rates from the line of gastroenterostomy and enteroenterostomy after LRYGB. He did not find any dependence between a surgeon´s experience expressed as the number of surgical obesity treatment procedures performed and the rates of anastomotic leakage or dehiscence. Another paper reports that an operator´s experience affects the incidence of stapled anastomotic strictures between stomach and intestine or intestine and intestine, but does not influence body mass loss following surgery (20, 21).

Many authors believe that operating on obese patients older than 50 years is very risky and such procedures should be as rare as possible. The study by R. Gonzalez, which compared the outcome of surgical obesity treatment in patients younger than 50 and those older than 50 years of age, proved that the results were comparable and existing differences insignificant. Bigger differences are observed in patients with morbid obesity, operated on after the age of 60. The postoperative mortality rate in this group is around 0.7%. Cardiopulmonary complications are more common and problems with wound healing more severe (19, 20, 21). An important element of the assessment of surgical morbid obesity treatment outcome is the evaluation of reconstructive surgery after previous operations. It is now believed that in morbid obesity it is acceptable, or even recommended, to perform the surgical treatment in 2 or 3 stages. Data from multi-centre studies show that in super morbid obesity it is safer to proceed in a few stages than in one stage.

Thus, the outcome of multi-stage procedures and the outcome of reconstructive operations should be assessed separately. Most reconstructive surgery procedures can be done laparoscopically. These procedures do not belong to those of increased risk and their outcome is comparable with that of primary procedures (19, 21, 22).

It is obvious that the surgical treatment of obesity is now the most effective way to treat this severe disease with so many consequences. Surgical obesity treatment has developed significantly since the 1950s. Also the expectations of this branch of surgery have changed. It is not only the body mass loss that is the objective of the treatment. The patient should be able to resume normal life after surgery, free of co-morbidities, physically fit and with an appearance that does not attract the attention of others. And here we encounter the metabolic surgery (18, 19, 20, 23, 24). Technical improvement and development create new horizons for surgical obesity treatment, which can be exemplified by the introduction of robotics and procedures through natural body orifices (25, 26).