Comparison of laparoscopic sleeve gastrectomy to laparoscopic Roux-en-Y gastric bypass for morbid obesity in a military institution

Surgery for Obesity and Related Diseases 10 (2014) 269–276

Original article

Comparison of laparoscopic sleeve gastrectomy to laparoscopic Roux-en-Y gastric bypass for morbid obesity in a military institution David M. Lim, D.O.a, Janos Taller, M.D.a, William Bertucci, M.D.a, Robert H. Riffenburgh, Ph.D.b, Jack O’Leary, R.N.a, Gordon Wisbach, M.D.a,* b

a Department of General Surgery, Naval Medical Center San Diego, San Diego, California Clinical Investigation Department, Naval Medical Center San Diego, San Diego, California Received May 18, 2012; accepted August 15, 2012

Abstract

Background: Laparoscopic sleeve gastrectomy (LSG) is gaining acceptance in the bariatric community as a definitive weight loss procedure; however, longitudinal data remain limited. The objective of this study was to compare weight loss results of LSG with laparoscopic Roux-en-Y gastric bypass (LRYGB) up to 5 years postoperatively using anthropometric measurements. Methods: Prospectively collected bariatric database at the Naval Medical Center San Diego was retrospectively reviewed from 2005–2011 . Anthropometric factors, including weight and hip circumference were measured during standard yearly follow-up appointments. Surgical outcomes were tested by the Student t test and demographic variables by Fisher’s exact and Wilcoxon rank-sum tests. Results: Follow-up was achieved in 147/226 LRYGB versus 130/208 LSG at year 1, 92/195 versus 81/151 at year 2, 64/145 versus 50/100 at year 3, 32/81 versus 18/54 at year 4, and 12/42 versus 14/15 at year 5. The excess weight loss (EWL) for LRYGB versus LSG was 72% versus 64.7% at 1 year (P ¼ .002), 71.3% versus 65.5% at 2 years (P ¼ .113), and 68.3% versus 57.4% at 5 years (P ¼ .252), respectively. Similarly, the body mass index (BMI) decrease was statistically significant at 1 year (P ¼ .001) but not on subsequent annual visits. Mean percent body adiposity index (BAI) decrease was 28.4% for LRYGB versus 26.8% for LSG at 1 year (P ¼ .679) and 21.8% versus 29.8% at 2 years (P ¼ .134), respectively. Weight loss measured in terms of %EWL and decrease in BMI and BAI did not show significance between LRYGB and LSG 2 years after surgery. Conclusion: Our study provides similar long-term weight loss between LSG and LRYGB, and therefore, LSG is a viable option as a definitive bariatric procedure. (Surg Obes Relat Dis 2014;10:269-276.) Published by Elsevier Inc. on behalf of American Society for Metabolic and Bariatric Surgery.

Keywords:

Morbid obesity; Bariatric surgery; Roux-en-Y gastric bypass; Sleeve gastrectomy; Weight loss; Body adiposity index

Obesity is an unbridled twenty-first century epidemic that poses a medical and financial burden on society. In 2007, 66% of adults were overweight or obese in the United States, and by the year 2015, this percentage will increase to 75%, with 41% of adults being obese [1]. Morbid obesity can cause severe major sequelae, including metabolic This study was supported by the Naval Medical Center San Diego. * Correspondence: Gordon Wisbach, M.D., 4442 Vereda Luna Llena, San Diego, CA 92130. E-mail: [email protected]

syndrome, obstructive sleep apnea, osteoarthritis, and diabetes mellitus type 2; most important, these illnesses can resolve with significant weight loss. Although medical treatment can be successful in treating moderate obesity, surgical weight loss procedures are the most effective treatment for long-term weight loss in severe obesity [2]; therefore, weight loss surgery has been accepted to play a vital role in treating patients with metabolic syndrome, sleep apnea, osteoarthritis, and diabetes mellitus [3–6]. Currently, laparoscopic Roux-en-Y gastric bypass (LRYGB) is accepted as the gold standard weight loss procedure. First

1550-7289/14/$ – see front matter Published by Elsevier Inc. on behalf of American Society for Metabolic and Bariatric Surgery. http://dx.doi.org/10.1016/j.soard.2012.08.012

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Table 1 Number of cases (April to March) Time frame (year) LRYGB LSG

2010–2011 *

11 40*

2009–2010

2008–2009

2007–2008

2006–2007

2005–2006

31 57

50 51

64 46

39 39

42 15

LRYGB ¼ laparoscopic Roux-en-Y gastric bypass; LSG ¼ laparoscopic sleeve gastrectomy. Patients with o6 months of follow-up were omitted from this figure.

*

performed by laparoscopy in 1994 [7], LRYGB gradually gained popularity due to the benefits of minimally invasive surgery (MIS) as well as literature showing effectiveness in weight loss and co-morbidity resolution [2–6]. Laparoscopic sleeve gastrectomy (LSG) was introduced initially as a first step in a staged approach to biliopancreatic diversion with duodenal switch [8]. Favorable outcomes toward treating obesity-related co-morbidities led to the consideration of this first stage as a stand-alone procedure [9–11]. LSG is a restrictive technique performed by resecting most of the fundus of the stomach, but the weight loss may also be due to neurohormonal changes secondary to gastric resection or expedited nutrient transport into the small bowel [12]. Efforts are ongoing to elucidate the exact mechanism. Despite the unknown mechanism of this procedure, there has been rapid adoption of LSG due to excellent early weight loss data, ease of procedure, and comparable or decreased complication rate in comparison with LRYGB [13–16]. The first objective of this study is to compare postoperative weight loss results of LRYGB versus LSG postoperatively from 1 year to 5 years to determine whether LSG is a feasible alternative for long-term weight loss to LRYGB. The second objective of this study is to introduce a unique application to measure percent body adiposity loss called body adiposity index (BAI) that is based on a hip circumference to height rather than weight to height ratio. Methods The study population consisted of a consecutive series of patients who underwent LRYGB or LSG for morbid obesity from August 2005 to March 2011 at a group bariatric practice at the Naval Medical Center San Diego, California. After institutional review board approval, our prospectively collected bariatric database was retrospectively reviewed and revealed 485 patient candidates. All patients were military retirees or family members of active duty service personnel; no patients were active duty. The postoperative weight loss surgery longitudinal visits were scheduled at 6 months, 1 year, and then annually. When indicated, more frequent clinical visits occurred; however, the data point closest to the patient’s annual follow-up was used for data analysis. Furthermore, patients who received the procedure before March 2011 who did not have at least 6 months of follow-up were excluded. The number of procedures performed for each year time frame was established

(Table 1), and the number of eligible patients for annual follow-up was determined. The eligible number of patients was then compared with actual number of patients followed up to calculate the final percentage (Table 2). All patients were evaluated in terms of weight loss, resolution of comorbidities, and complications, although co-morbidities and complications were not included in the scope of this paper. Starting in 2008, all patients underwent additional anthropometric measurements, including hip circumference. Mean excess weight loss (EWL), mean decrease in body mass index (BMI), and mean percent decrease in BAI were extrapolated. EWL was calculated using ‘‘ideal’’ weights for women and men described by National Institutes of Health [17]. BMI was defined as the individual’s body mass divided by the square of his or her height (kg/m2). BAI was derived using the formula described by Bergman et al. [18], using patient’s hip measurement as a parameter to define patient’s adiposity after surgery. BAI ¼

Hip pffiffiffiffiffiffiffiffiffiffiffiffiffi 18 Height Height

We performed a statistical analysis of each patient’s continuous variables in comparison to his or her baseline characteristics. All results are expressed as the mean and standard deviations, except as indicated. Possible differences between groups were tested by the t test and demographic variables by Fisher’s exact and rank-sum tests. The durability of each procedure was analyzed using regression line Table 2 Number of patients eligible for annual follow-up versus number of patients lost to follow-up Postoperative year Group

1

2

3

4

5

LRYGB Eligible for follow-up Actual no. of patients followed-up* No. of patients lost to follow-up % followed-up LSG Eligible for follow-up Actual no. of patients followed-up* No. of patients lost to follow-up % followed-up

226 147 79 65.0 208 130 78 62.5

195 92 103 47.2 151 81 70 53.6

145 64 81 44.1 100 50 50 50.0

81 32 49 39.5 54 18 36 33.3

42 12 30 28.6 15 14 1 93.3

LRYGB ¼ laparoscopic Roux-en-Y gastric bypass; LSG ¼ laparoscopic sleeve gastrectomy. * Only 1 visit per patient per year was recorded if multiple visitations were made in 1 year. Selection was made on the data point closest to actual annual follow-up date.

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on postoperative %EWL. Statistical significance was interpreted considering a P value o.05.

completed to create a gastrojejunostomy. A methylene blue leak test was performed to assess the gastrojejunostomy.

Roux-en-Y gastric bypass

Sleeve gastrectomy (laparoscopic and robotic)

Two different methods were used in our institution. Totally linear stapled technique. Four ports were used for access to the abdomen, and a Nathanson liver retractor (Mediflex, Bloomington, IN) was placed through a stab incision in the epigastrium to expose the hiatus. The anterior surface of the stomach was marked after advancing an orogastric tube into the stomach and insufflating a 30-mL balloon in the proximal stomach. The balloon was then desufflated and retracted into the esophagus. With use of the harmonic scalpel, the retrogastric space was entered through the pars flaccida to divide the gastrohepatic ligament to the level of the anterior gastric marks. A linear laparoscopic stapler with a 3.5-mm staple height was used to create the gastric pouch based on the lesser curvature blood supply. The stomach was fully divided, and the fundus was excluded. After an anterior gastrotomy was made using harmonic scalpel, a loop of jejunum, 30–60 cm from the ligament of Treitz, was pulled without tension in an antecolic antegastric fashion to the gastric pouch. After an enterotomy on the antimesenteric side of the loop was created, the gastrojejunostomy was fashioned between the enterotomy and gastrotomy using a linear laparoscopic stapler with a 3.5-mm staple height. The orogastric tube was then advanced across the anastomotic defect into the Roux limb. Another enterotomy was created 100 cm distally down the Roux limb, on the antimesenteric side, using the harmonic scalpel. As for the distal end of the biliary limb, an enterotomy was made on the antimesenteric side, and then the jejunojejunostomy was formed using a linear laparoscopic stapler with a 2.5-mm staple height between the 2 enterotomies. A leak test was performed by insufflating the gastric pouch with methylene-stained saline. Hand-sewn technique (laparoscopic and robotic). The operation was initiated in a similar fashion, including the same 4-ports technique. A perigastric technique along the lesser curve was used to gain access to the lesser sac. The gastric pouch was created by using a linear laparoscopic stapler with a 3.5-mm staple height to divide the stomach transversely 5–7 cm from the gastroesophageal junction. From the ligament of Treitz, the proximal jejunum (or biliopancreatic limb) was measured 30–60 cm and divided with a linear laparoscopic stapler of 2.5-mm staple height. An additional 100 cm of jejunum (or the roux limb) was measured, and a stapled jejunojejunostomy was created. The mesenteric defect was closed with a running permanent suture. After steep reverse Trendelenburg positioning, the case was continued laparoscopically or the robot was docked for the robotic-assisted technique; the same 4-ports technique was used for either method. The 34F orogastric tube was orally placed for sizing; a 2-layered sewn anastomosis was

The operation was initiated in a similar fashion, including using the same 4-ports technique. The patient was placed in steep reverse Trendelenburg position, and the procedure continued laparoscopically or the robot was docked for robotic assistance. A point on the greater curvature of the stomach 8 cm proximal to the pylorus was identified for later transaction. The lesser sac was entered using ultrasonic shears, and the greater curvature was mobilized from the omentum up to the left crus of the diaphragm. Any retrogastric attachments to the posterior stomach were divided to ensure complete mobilization of the stomach while preserving the lesser curve blood supply. A 32F orogastric tube was placed into the distal stomach against the lesser curve to provide a sizing guide. Starting at the previously marked point along the greater curvature, serial firing of a laparoscopic stapler by the operative field surgeon resulted in a partial gastrectomy that excluded the fundus. A 4.8-mm staple height was used across the antrum, and 3.5-mm staple height fired to the angle of His. The stomach was extracted through a trocar site. A methylene blue leak test was performed to evaluate the integrity of the long staple line. Results The study group consisted of 485 patients (443 women, 42 men) who underwent either LRYGB or LSG. The 2 groups of patients had similar distribution of age, gender, preoperative BMI, and hip size without any significant statistical differences (Table 3). The annual number of LRYGB has not shown any significant trend since 2005, although there is an increase in number of cases for LSG with time (Table 1). Furthermore, there is a gradual decline in follow-up ratio up until year 5 follow-up for both procedures. At year 5, however, a Table 3 Patient preoperative demographic characteristics Characteristics

LRYGB (n ¼ 237)

LSG (n ¼ 248)

P value

Gender, F/M Female age, median (range) Male age, median (range) Female BMI, mean (range) Male BMI, mean (range) Hip size in inches, median (range)

219/18 40 (22–69) 54 (26–67) 41 (30–63) 41 (34–55) 53 (41–65)y

224/24 39 (22–68) 52 (23–68) 40 (33–70) 42 (35–78) 52 (42–68)z

0.425* 0.063 0.493 0.248 0.647 0.448

LRYGB ¼ laparoscopic Roux-en-Y gastric bypass; LSG ¼ laparoscopic sleeve gastrectomy; F/M ¼ number of female/male; BMI ¼ body mass index. * Derived from Fisher’s exact test; remaining P values are derived using rank-sum test. y Measurements from n ¼ 68. z Measurements from n ¼ 127.

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Fig. 1. Mean percent excess weight loss (EWL) with error bars (shown above mean for LRYGB and below mean for LSG) indicating standard deviation for post-bariatric surgery from 0–5 years follow-up. LRYGB versus LSG. Follow-up ratio indicated on each data point starting from year 1.

significantly higher percentage of follow-up was noticed for patients who underwent LSG (93.3%), whereas continued decline was seen for those who received LRYGB (28.6%). Combined, our study had 26 patients (12 LRYGB and 14 LSG), with 57 patients eligible for 5-year follow-up, which is approximately a 45.6% follow-up rate. The resulting power of our study was 89% at 1 year, and 2- to 5-year powers culminated at 45% and 23%, respectively. Mean %EWL and mean BMI decrease for the 2 groups are shown in Figs. 1 and 2. At year 1 postoperation, LRYGB weight loss is statistically greater than that achieved with LSG (P = .002), but by year 2 and later, LSG weight loss was comparable to that achieved with LRYGB. Durability, which was verified using a regression line on %EWL, had a slope of .59% per year (P = .479) for LRYGB and a slope .39% per year (P = .479) for LSG. Using patients’ hip measurements, BAI was calculated for each group up to 2 years. Unlike the significant weight loss measured by mean %EWL and mean decrease in BMI, measurement of adiposity loss or mean %BAI decrease between LRYGB and LSG indicated no statistical difference up to 2 years postoperatively (Table 2 and Fig. 3). Discussion With obesity reaching a pandemic level, bariatric procedures will be increasingly used due to the proven durability of significant weight loss resulting in decrease of co-morbidities [19]. Of the available procedures, Roux-

en-Y gastric bypass is the most commonly performed, with superior efficacy, and remains the gold standard weight loss procedure [20,21]. Numerous other operative procedures have been implemented but failed to provide a viable replacement for laparoscopic LRYGB. The latest procedure to gain popularity and acceptance is LSG. Short-term results are abundant and predominantly supportive of this weight loss procedure; however, there remains a paucity of long-term data [11,22–25]. Our study found statistically greater weight loss with LRYGB at 1 year postoperation, but subsequently, there was an equivalency with that achieved with LSG. The hybrid weight loss mechanism of the LRYGB with both restrictive and malabsorptive effects may contribute to greater short-term weight loss; long-term weight loss may result from exclusion of the fundus shared by both procedures. The equivalency between these 2 procedures is consistent with other studies, including randomized designs [13,14]. The durability of weight loss with LSG is evidenced by 455% EWL up to 5 years postoperation and by negligible change in regression line or best-fit line. According to Reinhold criteria, the weight loss result after bariatric surgery is ‘‘excellent’’ when the percentage of excess weight lost is 475%; ‘‘good’’ between 50% and 75%; ‘‘fair’’ from 25% to 50%; and ‘‘poor’’ below 25% [26]. Per Reinhold criteria, our study reported good results by both procedures up to 5 years. Similar durability of weight loss after LSG is also seen in other studies [27–30]. A more detailed and proven mechanism of action for these 2 weight loss surgeries remains to be elucidated.

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Fig. 2. Mean body mass index (BMI) decrease with error bars (shown above mean for LRYGB and below mean for LSG) indicating standard deviation for post-bariatric surgery from 0–5 years follow-up. LRYGB versus LSG. Follow-up ratio indicated on each data point starting from year 1.

LRYGB is considered a hybrid procedure that includes both restriction and malabsorptive characteristics. Although the exact mechanism by which weight loss is achieved is not well understood, some speculated that LRYGB accomplished weight loss through substantial malabsorption and the dumping effect [31]. Contrarily, reports from MacLean et al. [32] and Cummings et al. [33] reported that there is no

Fig. 3. Mean percent body adiposity index (BAI) with error bars (shown above mean for LRYGB and below mean for LSG) indicating standard deviation for post-bariatric surgery from 0–2 years follow-up for BAI. LRYGB versus LSG. Follow-up ratio indicated on each data point starting from month 6.

significant malabsorption after a gastric bypass, with dumping effects being applicable only to sweet consumers. Evidence for LRYGB supports an increase in anoretic hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) or a decrease in orexigenic hormone ghrelin [34–36]. However, a prospective, double-blind study conducted by Karamanakos et al. [14] reported that ghrelin may not play a significant role in weight loss due to inconsistent findings of ghrelin level postoperatively. Finally, studies demonstrate that gastric bypass may promote weight loss by reducing the food cues in mesolimbic pathway [37]. LSG is a restrictive procedure due to a partial gastrectomy and does not offer any known malabsorptive characteristics. There are indications that this procedure may cause weight loss by effects on ghrelin levels. Initial level of ghrelin may decrease with reduction of ghrelin producing cells from excision of the fundus. According to Bohdjalian et al. [30], this decrease is sustained up to 5 years in a longitudinal study, with a mean EWL of 55%. Wang and Liu [38] also reported a similar decrease in plasma ghrelin levels 2 years after LSG. Santoro et al. [39] reported that PYY response to food was enhanced after several bariatric procedures, including LSG, an omentectomy, and a jejunectomy, for 1 and 5 years. However, this effect seems to be transient due to physiologic adaptation of the gastric remnant [14]. Although the mechanism of action for the bariatric procedures is not fully understood, a commonality is exclusion of the gastric fundus from the functional alimentary tract. The neurohormonal effect of the fundus

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requires further elucidation. The benefit of weight loss surgery should be offered to obese patients, and further study is required in this burgeoning area of research. Of the currently accepted weight loss procedures, LSG will likely become the most common bariatric operation in the United States over the next 5 years, foreshadowed by the increasing popularity in our institution. Factors supporting this prediction include the technical ease compared with LRYGB, lower complication rate [15,16], and similar comorbidity reduction profile [40–42]. The estimated total cost of LSG excluding the cost of further surgical intervention is $1300 (in Canadian dollars) lower than LRYGB according to data published from the Royal Alexandra Hospital [43]. Potential complications unique to LSG include potential leaks along a long staple line, narrowing of the gastroesophageal junction or incisura, and developing worse reflux symptoms [44–46]. A possible study limitation was the variation in operative technique for the LRYGB with a total linear stapler or a hand-sewn method. Despite this variation, the patients underwent a similar hybrid operation that offered restriction and malabsorption in a gastric bypass configuration. Other variations included use of laparoscopy or robotic assistance. The LSG technique was more standardized in our program; however, like the LRYGB, some of these operations were performed with robotic assistance. The intent of robotic surgery is to facilitate performing the same operation offered laparoscopically for LRYGB or LSG, thereby providing a similar context to compare the two procedures. Although the potential differences are estimated to be minimal, further study of these operative techniques and outcomes is necessary. A challenge encountered in our bariatric study was maintaining long-term follow-up for our patients. Distinctive to the military community is our transient population due to base transfers and deployments as well as attrition from active-duty status, which leads to family members’ loss of military medical benefits. However, maintaining an adequate long-term follow-up seems to be a universal challenge among other nonmilitary institutions. According to American Society for Metabolic and Bariatric Surgery’s ‘‘Updated Position Statement on Sleeve Gastrectomy as a Bariatric Procedure,’’ revised October 2011, 6 groups are reporting on long-term efficacy (Z5 years) of sleeve gastrectomy [27–30,47,48]. Of these groups, the mean number of patients in each study was 22 (range, 8–41 ), although clear eligibility of each patients for long-term follow-up is not defined. Our overall follow-up rate of 45.6% is higher than those of other reports, including 22.5% by D’Hondt et al. [48], with an initial patient population of 102, and 6.7% by Weiner et al. [28], with an initial patient population of 120. Other long-term studies with higher follow-up rates had much smaller initial patient numbers [27,29,30,47]. These long-term studies lack the desired statistical power similar to our study as a result of

the poor follow up. However, this low power does not have an inimical effect on our conclusion. We have no evidence that one bariatric operation is better, given the similar successful weight loss results and demonstration of durability. Therefore, multiple clinical factors, including complication rate, co-morbidity resolution, and cost, along with patient and surgeon preferences, will play a dominant role in choosing an appropriate procedure. One of the unique aspects of our study was the incorporation of BAI to compare the two procedures. The impetus for incorporating this anthropometric measurement was the recognized weaknesses of the currently accepted approach to characterize an individual’s obesity, namely, BMI. BMI is a proxy for human body fat based on an individual’s weight and height. This measurement is inaccurate in measuring adiposity in individual patients as well as estimating obesity in athletes and in various ethnic groups [49–51]. The concept of BAI, calculated as the ratio of hip circumference to height times the square root of height, was used as a simple, inexpensive, and potentially more accurate means of measuring adiposity loss [18]. BAI has been validated from using percent body fat derived from dual-energy x-ray absorption (DXA). In our study, both LRYGB and LSG resulted in comparable adiposity loss up to 2 years postoperatively. This anthropometric measurement was introduced into our program in 2008; therefore, determining the longitudinal success of each procedure by BAI is ongoing. Importantly, BAI has stronger correlation to percent body fat calculated from dual-energy x-ray absorptiometry than BMI in nonstratified patients for their gender and age [52]. There are two main advantages of BAI as opposed to BMI. First, BAI does not require a weight measurement and avoids the need for an expensive bariatric scale, and it may be obtained with only the use of a tape measure. Therefore, it can be applied in a wider range of medical settings, including the primary care office without an expensive bariatric scale and the military healthcare system in a smaller U.S. medical clinic caring for an obese family member. Second, the BAI may be superior to BMI, because BMI cannot be generalized in certain populations such as athletes and children. Although the practicality of BAI application among bariatric patients in future healthcare remains to be seen, it may prove to be a useful alternative anthropometric parameter in the care of obese patients. Conclusion In conclusion, our study provides suggestive, long-term results with similar successful weight loss for LSG compared with LRYGB. The BAI is a unique method of determining percent adiposity that provides another anthropometric parameter in evaluating bariatric patients and demonstrated similar percent adiposity short-term loss between the two weight loss operations. The LSG should

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