Laparoscopic Sleeve Gastrectomy: Efficacy and Safety of Classic vs. Hard Techniques in Long-Term Weight Loss: A Retrospective Cohort Study

Abstract

Purpose

This study aimed to compare the efficacy and safety of Classic and Hard laparoscopic sleeve gastrectomy (LSG) techniques, with a focus on long-term weight loss outcomes and complication rates over a 3-year follow-up period.

Materials and Methods

A retrospective cohort study was conducted on 785 patients who underwent LSG between January 2019 and December 2022, with follow-up completed by 2023. Patients were divided into 2 groups according to surgical technique: Classic LSG (n=372), involving standard resection along the lesser curvature using a 36-French bougie; and Hard LSG (n=413), characterized by more extensive fundal mobilization and creation of a narrower gastric tube using a 32-French bougie.

Results

Both techniques resulted in significant body mass index (BMI) reductions; however, Hard LSG demonstrated superior weight loss. At 12 months, 70.7% of Hard LSG patients achieved a normal BMI (<25 kg/m²), compared to 42.2% in the Classic group. At 3 years, 59.3% and 20.4% maintained normal BMI, respectively (P<0.001). However, Hard LSG was associated with higher complication rates: early metabolic complications occurred in 64.3% vs. 25.7% (P<0.001), and late surgical complications in 10.4% vs. 2.4% (P<0.001).

Conclusion

While Hard LSG provides greater and more durable weight loss, it is associated with increased risks of complications. These findings support the need for individualized surgical decision-making to balance efficacy and safety in the management of obesity.

INTRODUCTION

The global obesity epidemic represents one of the most significant public health challenges of the 21st century. With steadily increasing prevalence across all age groups, obesity is strongly associated with multiple comorbid conditions, including type 2 diabetes mellitus, cardiovascular disease, obstructive sleep apnea, and non-alcoholic fatty liver disease [1]. Among available treatment modalities, bariatric surgery remains the most effective long-term intervention for achieving sustained weight loss and metabolic improvement in patients with severe obesity.

Laparoscopic sleeve gastrectomy (LSG) has emerged as the most commonly performed bariatric procedure worldwide due to its relative technical simplicity, lack of intestinal bypass, and favorable short- to mid-term outcomes [2]. Initially introduced as the first stage of a multistep approach for super-obese patients, LSG has evolved into a standalone operation with durable weight loss effects and metabolic benefits.

Despite its growing popularity, considerable variability persists in surgical technique among centers and individual surgeons. Two predominant approaches have been identified in clinical practice: Classic LSG, involving standard resection along the lesser curvature with limited fundal mobilization, and Hard LSG, which employs more extensive dissection and a narrower gastric tube. These differences may influence both weight loss durability and complication profiles.

While both techniques are technically feasible and generally safe, comparative long-term data on their efficacy and safety remain limited, particularly regarding weight loss sustainability and postoperative complications.

This retrospective cohort study aims to evaluate and compare the long-term outcomes of Classic and Hard LSG techniques over a 36-month follow-up period, focusing on weight loss effectiveness, metabolic stability, and postoperative complication rates. Findings may help guide individualized surgical decision-making in the management of morbid obesity.

MATERIALS AND METHODS

This retrospective cohort study evaluated 785 patients with morbid obesity who underwent LSG at a single center between January 2019 and December 2022. All participants had a minimum follow-up duration of 36 months, ensuring assessment of long-term outcomes. The primary endpoints included measures of weight loss efficacy—percentage total weight loss (%TWL), percentage excess weight loss (%EWL), and percentage excess body mass index (BMI) loss (%EBL)—as well as the incidence of early (within 30 days) and late (beyond 30 days) surgical and metabolic complications. A secondary endpoint was the rate of weight regain at 36 months postoperatively.

Patients were divided into 2 groups based on the surgical technique applied during the procedure:

• Classic LSG (n=372): This approach involved standard longitudinal resection along the lesser curvature of the stomach using a 36-French bougie for calibration, with limited fundal mobilization and preservation of anatomical structures around the angle of His.

• Hard LSG (n=413): This modified technique entailed a more proximal resection line, approximately 2–3 cm closer to the pylorus, and the use of a smaller 32-French bougie for gastric calibration. It also included complete dissection of the angle of His, extensive fundal mobilization, and creation of a more vertically oriented and restrictive gastric remnant.

Inclusion criteria were defined as follows: age between 18 and 65 years, preoperative BMI of 40 kg/m² or higher, or 35 kg/m² or higher with significant comorbid conditions; absence of prior bariatric surgical interventions; and availability of complete preoperative and follow-up data.

Exclusion criteria comprised follow-up duration shorter than 36 months, concomitant procedures such as hiatal hernia repair or revisional surgery, and incomplete documentation of postoperative outcomes.

Data collection encompassed demographic characteristics (age, sex, baseline BMI), intraoperative metrics (operative time, estimated blood loss, conversion rates), and postoperative outcomes (hospital length of stay, readmission rates, reoperation rates). Weight loss outcomes were calculated using the following formulas:

%TWL = [(Preoperative Weight − Current Weight)/Preoperative Weight] × 100

%EWL = [(Preoperative Weight − Current Weight)/Excess Weight] × 100

%EBL = [(Preoperative BMI − Current BMI)/Excess BMI] × 100

Postoperative complications were categorized according to the Clavien-Dindo classification system and stratified into early (occurring within 30 days) and late (beyond 30 days) events. Metabolic complications included metabolic acidosis, hypovolemia, hypercoagulability, and micronutrient deficiencies. Surgical complications consisted of bleeding, anastomotic leak, thromboembolic events, stenosis, and gastroesophageal reflux disease (GERD).

Statistical analysis was performed using IBM SPSS Statistics version 27.0 (IBM Corp., Armonk, NY, USA). Continuous variables were presented as mean ± standard deviation and compared using independent samples t-tests. Categorical variables were analyzed using the χ² test. Statistical significance was set at P<0.05.

Technique selection was guided by institutional guidelines based on the following criteria:

• - Baseline BMI (>45 kg/m² favored Hard LSG)

• - Presence of metabolic syndrome (elevated HbA1c or insulin resistance favored Hard LSG)

• - Preoperative GERD severity (mild GERD was not considered a contraindication)

• - Intraoperative gastric anatomy (greater fundal volume favored Hard LSG)

All decisions were made by experienced bariatric surgeons, and intraoperative findings were used to confirm final technique selection.

1. Ethical approval

The study protocol was approved by the Institutional Ethics Committee of Tashkent Medical Academy (Ref: TMA/IRB/2018-12). Written informed consent was obtained from all participants. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments.

RESULTS

This retrospective cohort study evaluated 785 patients who underwent LSG between January 2019 and December 2022, with a minimum follow-up of 36 months. Patients were divided into 2 groups based on surgical technique: Classic LSG (n=372) and Hard LSG (n=413) (Table 1).

Table 1. Baseline demographic and clinical characteristics.

Variable	Classic LSG (n=372)	Hard LSG (n=413)	P value
Age (years)	42.3±6.5	43.1±6.8	0.092
Female	250 (67.2)	275 (66.6)	0.854
Preoperative BMI (kg/m2)	45.2±5.1	46.7±5.9	<0.050
Diabetes mellitus	132 (35.5)	167 (40.4)	<0.050
Hypertension	174 (46.8)	203 (49.1)	0.403
Obstructive sleep apnea	89 (23.9)	112 (27.1)	0.247
GERD symptoms	45 (12.1)	78 (18.9)	<0.050

Values are presented as mean ± standard deviation or number (%).

LSG = laparoscopic sleeve gastrectomy, BMI = body mass index, GERD = gastroesophageal reflux disease.

There were no significant differences in age (P=0.092), sex (P=0.854), hypertension (P=0.403), or obstructive sleep apnea (P=0.247) between the 2 groups. However, patients in the Hard LSG group had a significantly higher preoperative BMI (46.7±5.9 vs. 45.2±5.1 kg/m², P<0.05), higher rates of type 2 diabetes mellitus (40.4% vs. 35.5%, P<0.05), and a greater proportion with preoperative GERD symptoms (18.9% vs. 12.1%, P<0.05).

Both surgical approaches resulted in substantial weight loss; however, the Hard LSG group demonstrated significantly greater and more durable outcomes.

At 12 months postoperatively, 70.7% of patients in the Hard LSG group achieved a normal BMI (<25 kg/m²), compared to 42.2% in the Classic group. By 36 months, sustained BMI normalization was maintained in 59.3% of Hard LSG patients vs. 20.4% in the Classic group (P<0.001) (Tables 2 and 3).

Table 2. Mean weight loss parameters at 12 months post-surgery.

Parameter	Classic LSG (n=372)	Hard LSG (n=413)	P value
%TWL	35.3±9.7	38.6±8.5	<0.001
%EWL	68.4±15.2	71.9±13.7	<0.001
%EBL	72.5±16.3	75.6±14.9	<0.001

Values are presented as mean ± standard deviation.

LSG = laparoscopic sleeve gastrectomy, %TWL = percentage total weight loss, %EWL = percentage excess weight loss, %EBL = percentage excess body mass index loss.

Table 3. Distribution of patients by BMI categories at 12 months.

BMI category	Classic LSG (%)	Hard LSG (%)	P value
Normal BMI (<25 kg/m2)	42.2	70.7	<0.001
Overweight (25–29.9 kg/m2)	36.8	23.7	<0.001
Obesity grade I (30–34.9 kg/m2)	15.6	4.4	<0.001
Obesity grade II (≥35 kg/m2)	5.4	1.2	<0.001

BMI = body mass index, LSG = laparoscopic sleeve gastrectomy.

Hard LSG was associated with significantly lower rates of weight regain. By 36 months, 62.37% of patients in the Classic LSG group experienced weight regain (defined as an increase of ≥1 BMI category), compared to only 40.7% in the Hard LSG group (P<0.001).

1. Complication rates

Although Hard LSG yielded superior weight loss, it was associated with a significantly higher incidence of early and late complications.

2. Early complications

Early complications were categorized as metabolic or surgical (Table 4).

Table 4. Early metabolic complications within 30 days post-surgery.

Complication	Classic LSG (%)	Hard LSG (%)	P value
Metabolic acidosis	14.75	39.76	<0.001
Hypovolemia	18.23	50.36	<0.001
Hypercoagulability	2.41	19.28	<0.001
Severe liver failure	0.00	0.24	0.640
Any metabolic complication	25.74	64.34	<0.001

"Any metabolic complication" refers to the composite outcome of one or more of the listed metabolic events.

LSG = laparoscopic sleeve gastrectomy.

The overall rate of any early metabolic complication was significantly higher in the Hard LSG group (64.3% vs. 25.7%, P<0.001) (Table 5).

Table 5. Early surgical complications within 30 days post-surgery.

Complication	Classic LSG (%)	Hard LSG (%)	P value
Bleeding	0.54	0.72	1.000
Anastomotic leak	0.00	0.48	0.498
Pulmonary embolism	0.27	0.24	1.000
Mesenteric venous thrombosis	0.00	0.24	0.640
Trocar site bleeding	0.54	0.72	1.000
Total surgical complications	1.34	2.41	0.273

"Total surgical complications" represents the cumulative incidence of any of the listed surgical events.

LSG = laparoscopic sleeve gastrectomy.

There was no statistically significant difference in the overall rate of early surgical complications between the 2 groups (2.41% vs. 1.34%, P=0.2728).

3. Late complications

During the 1–36 months follow-up period, late complications were significantly more frequent in the Hard LSG group (Table 6).

Table 6. Late surgical and metabolic complications (1–36 months).

Complication	Classic LSG (%)	Hard LSG (%)	P value
Gastroesophageal reflux disease	0.7	5.1	<0.001
Gastric stenosis	0.2	1.7	<0.001
Micronutrient deficiency	1.1	3.4	<0.001
Reoperation/revision surgery	0.3	0.9	0.367
Total complications	2.4	10.4	<0.001

LSG = laparoscopic sleeve gastrectomy.

The total rate of late complications was significantly higher in the Hard LSG group (10.4% vs. 2.4%, P<0.001). The most notable differences were in the incidence of GERD (5.1% vs. 0.7%, P<0.001), gastric stenosis (1.7% vs. 0.2%, P<0.001), and micronutrient deficiencies (3.4% vs. 1.1%, P<0.001).

Two patients in the Hard LSG group developed severe gastric stenosis at the angular incisura, necessitating revisional surgery to Roux-en-Y gastric bypass due to cachexia and persistent vomiting.

DISCUSSION

The comparative analysis of Classic and Hard LSG techniques reveals a clear clinical trade-off between weight loss efficacy and postoperative complication risk. While both approaches are technically feasible and widely used, Hard LSG—characterized by extensive fundal mobilization, a more proximal resection line, and narrower gastric calibration—demonstrates significantly greater short- and long-term weight loss compared to Classic LSG.

Consistent with prior evidence, Hard LSG achieved higher rates of BMI normalization at 12 months (70.7%) and 36 months (59.3%) compared to Classic LSG (42.2% and 20.4%, respectively). This improved outcome is likely attributable to increased gastric restriction and reduced gastric capacity, resulting in earlier satiation and lower caloric intake. Furthermore, Hard LSG was associated with significantly lower rates of weight regain over a 3-year follow-up, reinforcing its role in achieving durable weight control.

However, this enhanced efficacy comes at the cost of a higher incidence of both early and late complications. Early metabolic complications—including metabolic acidosis, hypovolemia, and hypercoagulability—occurred in 64.3% of Hard LSG patients vs. 25.7% in the Classic group (P<0.001). These findings suggest that aggressive gastric restriction may disrupt fluid and electrolyte homeostasis, necessitating close metabolic monitoring and proactive hydration management in the early postoperative period.

Late surgical complications were also significantly more frequent in the Hard LSG group (10.4% vs. 2.4%, P<0.001), primarily due to the development of GERD and gastric stenosis. Symptomatic narrowing at the angular incisura was observed in 2 patients, necessitating revisional surgery to Roux-en-Y gastric bypass due to cachexia and persistent vomiting. These cases highlight the importance of meticulous surgical technique—particularly in relation to staple line tension and preservation of the angularis incisura—to minimize the risk of mechanical obstruction.

A notable finding is the association between extensive fundal dissection and angular incisura stenosis. Complete mobilization of the short gastric vessels may alter the biomechanics of the gastric angle, increasing tension along the staple line and potentially compromising local vascularity. This may predispose to ischemia, fibrosis, and luminal narrowing, particularly at the angularis incisura. Surgeons should be mindful of preserving the left gastric artery branches and minimizing traction during stapling to maintain perfusion and reduce stenosis risk.

Notably, a higher proportion of patients with preoperative GERD symptoms were assigned to the Hard LSG group (18.9% vs. 12.1%, P<0.05). While this may appear counterintuitive given the increased risk of postoperative GERD associated with greater gastric restriction, the decision was guided by a multifactorial assessment, including baseline BMI (>45 kg/m²), presence of metabolic syndrome, and intraoperative gastric anatomy. In selected cases, the potential for superior weight loss was prioritized over the risk of GERD exacerbation, particularly in patients without hiatal hernia or esophagitis. These findings underscore the importance of individualized decision-making and suggest that mild preoperative GERD should not be an absolute contraindication to Hard LSG, provided that patients are adequately counselled and monitored.

The study identifies several potential risk factors for increased complication rates following Hard LSG. Patients with baseline micronutrient deficiencies, preoperative dehydration, or a history of GERD appeared more susceptible to metabolic and surgical complications. These findings support the need for comprehensive preoperative evaluation and tailored patient selection.

This study has several limitations. Its retrospective, single-center design may limit generalizability. Although all procedures were performed by experienced bariatric surgeons, variability in surgical technique could influence outcomes. Moreover, the non-randomized allocation introduces the possibility of selection bias. Prospective, multicenter studies are warranted to validate these findings and refine patient selection criteria.

Despite these limitations, this study contributes meaningfully to the ongoing discussion about balancing efficacy and safety in bariatric surgery. As the global burden of obesity grows, surgical strategies must be individualized to optimize outcomes based on each patient’s metabolic profile, comorbidity burden, and lifestyle.

CONCLUSION

Hard LSG provides significantly greater and more durable weight loss compared to Classic LSG, but at the cost of higher early metabolic and late surgical complication rates. These findings highlight a critical trade-off between efficacy and safety in bariatric surgery. While Hard LSG may be preferable for patients with high metabolic risk or extreme obesity, Classic LSG offers a safer profile for those prioritizing postoperative stability. The choice between techniques should be individualized, based on comprehensive assessment of BMI, comorbidities, GERD status, and patient goals. Future prospective studies are needed to validate these outcomes and refine selection criteria.