Morbid ObesityTSBL-OAGBNCT07796503
TSBL-Based Versus BMI-Based Biliopancreatic Limb Length in One-Anastomosis Gastric Bypass
A study testing TSBL-based biliopancreatic limb length determination and BMI-based biliopancreatic limb length determination in people with Morbid Obesity and Obesity, run by National Scientific Center of Surgery named after A.N.Syzganov at 1 site in Kazakhstan.
Trial summary
This study compares two surgical techniques used during one-anastomosis gastric bypass (OAGB) surgery for patients with severe obesity. During this operation, surgeons create a bypass of part of the small intestine, and the length of this bypassed segment (called the biliopancreatic limb) affects both weight loss and… Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Morbid Obesity, Obesity
- What is being tested?
- TSBL-based biliopancreatic limb length determination and BMI-based biliopancreatic limb length determination
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteKazakhstan
- Study dates
- 1 Oct 2023to 1 Nov 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age between 18 and 65 years
- BMI ≥35 kg/m² in non-Asian populations or ≥32.5 kg/m² in Asian populations
- Presence or absence of metabolic comorbidities (including type 2 diabetes, hypertension, and dyslipidaemia)
- Eligibility for primary one-anastomosis gastric bypass (OAGB)
- Provision of written informed consent
Who cannot join
- BMI below the defined thresholds
- Severe decompensated cardiac, pulmonary, hepatic, or renal disease
- Acute inflammatory conditions
- Active gastric or duodenal ulcer
- Psychiatric disorders or substance abuse
- Pregnancy or breastfeeding
Show all 9Show fewer
- Active malignancy
- Severe intra-abdominal adhesions due to prior surgery
- Secondary obesity related to hypothalamic-pituitary-adrenal axis disorders
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Kazakhstan1 site, 1 recruiting
- Recruiting
JSC "National Scientific Center of Surgery named after A.N. Syzganov"
Almaty
Nurbol Orynbassar, +77474528797, nurbolorynbassar@gmail.com
Adil Shokebaev
About this study
Official title: TSBL-Based Versus BMI-Based Biliopancreatic Limb Length in One-Anastomosis Gastric Bypass: Interim Results of a Randomized Trial
This study compares two surgical techniques used during one-anastomosis gastric bypass (OAGB) surgery for patients with severe obesity. During this operation, surgeons create a bypass of part of the small intestine, and the length of this bypassed segment (called the biliopancreatic limb) affects both weight loss and the risk of nutritional side effects. In this trial, one group of patients has the limb length calculated individually based on the measured total length of their small intestine (TSBL-based method), while the other group receives a limb length based on standard body mass index (BMI) categories (BMI-based method). The study compares weight loss outcomes, improvement of obesity-related health problems, and complication rates between the two approaches over 12 months after surgery. The trial is being conducted at a single center in Almaty, Kazakhstan, and plans to enroll 100 patients total; this record reflects an interim analysis based on the first 75 patients enrolled.
Read the detailed description
This is a single-center, prospective, randomized controlled trial comparing two methods for determining biliopancreatic limb length (BPLL) during laparoscopic one-anastomosis gastric bypass (OAGB) in patients with morbid obesity. Eligible patients aged 18-65 years with BMI ≥35 kg/m² (non-Asian) or ≥32.5 kg/m² (Asian populations) who were candidates for primary OAGB were randomized 1:1 using a computer-generated randomization sequence with sequentially numbered, opaque sealed envelopes.
In the intervention (TSBL-based) group, total small bowel length (TSBL) was measured intraoperatively from the ligament of Treitz to the ileocecal valve, and BPLL was calculated as 0.35 × TSBL. In the control (BMI-based) group, BPLL was determined using standard fixed lengths based on BMI category (150 cm, 180 cm, or 200 cm). All other surgical steps were identical between groups.
The primary outcome is percentage excess weight loss (%EWL) assessed longitudinally at baseline, 3, 6, and 12 months. Secondary outcomes include percentage total weight loss (%TWL), BMI, BMI loss, improvement of obesity-related comorbidities, and postoperative complications graded using the Clavien-Dindo classification. Statistical analysis uses linear mixed models to evaluate effects of group, time, and group-by-time interaction.
Because blinding of patients and surgeons was not feasible given the nature of the surgical intervention, outcome assessment relied on objective anthropometric and clinical measures. This record reflects a planned interim analysis conducted on the first 75 of a planned total of 100 enrolled patients, with 51 patients having completed 12-month follow-up at the time of this analysis.
- Conditions
- Morbid Obesity, Obesity
- Being tested
- TSBL-based biliopancreatic limb length determination, BMI-based biliopancreatic limb length determination
- Keywords
- One Anastomosis Gastric Bypass, Biliopancreatic Limb Length, Bariatric Surgery, Total Small Bowel Length, Weight Loss
- Medical subject headings
- Obesity, Morbid, Obesity, Weight Loss
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TSBL-based biliopancreatic limb length determinationProcedure or surgery
Biliopancreatic limb length individualized intraoperatively based on measured total small bowel length (TSBL), calculated as BPL = 0.35 × TSBL, prior to laparoscopic one-anastomosis gastric bypass.
BMI-based biliopancreatic limb length determinationProcedure or surgery
Biliopancreatic limb length determined using standard fixed lengths based on preoperative BMI category (150 cm, 180 cm, or 200 cm), prior to laparoscopic one-anastomosis gastric bypass.
| Study group | Role | What they receive |
|---|---|---|
| TSBL-Based Group | Experimental | Biliopancreatic limb length (BPL) individualized based on intraoperatively measured total small bowel length (TSBL), calculated as BPL = 0.35 × TSBL. Receives: Procedure: TSBL-based biliopancreatic limb length determination |
| BMI-Based Group | Active comparator | Biliopancreatic limb length (BPL) determined using standard fixed lengths based on BMI category: 150 cm for BMI 35-39.9, 180 cm for BMI 40-49.9, 200 cm for BMI ≥50. Receives: Procedure: BMI-based biliopancreatic limb length determination |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of Excess Weight Loss (%EWL)
EWL defined as the proportion of weight loss relative to excess baseline weight, with ideal body weight defined as BMI 25 kg/m². Assessed longitudinally over time using linear mixed models.
Measured: Baseline, 3 months, 6 months, and 12 months post-surgery
Secondary outcomes (5)
Percentage of Total Weight Loss (%TWL)
TWL assessed as percentage of total body weight loss relative to baseline weight. Assessed longitudinally over time using linear mixed models.
Measured: Baseline, 3 months, 6 months, and 12 months post-surgery
BMI Change
Change in body mass index (BMI, kg/m²) from baseline over time.
Measured: Baseline, 3 months, 6 months, and 12 months post-surgery
BMI Loss (BMIL)
Reduction in BMI from baseline, expressed as BMI loss (BMIL).
Measured: Baseline, 3 months, 6 months, and 12 months post-surgery
Improvement in Obesity-Related Comorbidities
Change in obesity-related comorbidities, including hypertension and ischemic heart disease, compared between groups.
Measured: 12 months post-surgery
Postoperative Complications
Postoperative complications documented and categorized according to the Clavien-Dindo classification system, including anaemia, hair loss, and bowel movement disorder.
Measured: 12 months post-surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Sep 2026
- Study start1 Oct 2023
- Primary completion1 Nov 2027 (estimated)
- Study completion1 Nov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Morbid ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Scientific Center of Surgery named after A.N.Syzganov
- Sponsor type
- Other government
- Collaborators
- Kazakh Medical University "Higher School of Public Health", Klaipėda University
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07796503
- Sponsor's protocol ID
- TSBL-BMI-OAGB
- Acronym
- TSBL-OAGB
- Status last verified
- Aug 2026
- First submitted
- 27 Aug 2026
- Last updated
- 1 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data underlying the results reported in this article, after deidentification, may be shared with researchers upon reasonable request.
Study at a glance
From the registry record, last updated by the sponsor on 1 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- TSBL-Based Versus BMI-Based Biliopancreatic Limb Length in One-Anastomosis Gastric Bypass: Interim Results of a Randomized Trial
- ClinicalTrials.gov ID
- NCT07796503
- Acronym / sponsor ID
- TSBL-OAGB / TSBL-BMI-OAGB
- Conditions
- Morbid Obesity, Obesity
- Keywords
- One Anastomosis Gastric Bypass, Biliopancreatic Limb Length, Bariatric Surgery, Total Small Bowel Length, Weight Loss
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- National Scientific Center of Surgery named after A.N.SyzganovOther government
- Collaborators
- Kazakh Medical University "Higher School of Public Health", Klaipėda University
- Study start
- 1 Oct 2023 (actual)
- Primary completion
- 1 Nov 2027 (estimated)
- Study completion
- 1 Nov 2027 (estimated)
- First posted
- 1 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study compares two surgical techniques used during one-anastomosis gastric bypass (OAGB) surgery for patients with severe obesity. During this operation, surgeons create a bypass of part of the small intestine, and the length of this bypassed segment (called the biliopancreatic limb) affects both weight loss and the risk of nutritional side effects. In this trial, one group of patients has the limb length calculated individually based on the measured total length of their small intestine (TSBL-based method), while the other group receives a limb length based on standard body mass index (BMI) categories (BMI-based method). The study compares weight loss outcomes, improvement of obesity-related health problems, and complication rates between the two approaches over 12 months after surgery. The trial is being conducted at a single center in Almaty, Kazakhstan, and plans to enroll 100 patients total; this record reflects an interim analysis based on the first 75 patients enrolled.
Detailed description
This is a single-center, prospective, randomized controlled trial comparing two methods for determining biliopancreatic limb length (BPLL) during laparoscopic one-anastomosis gastric bypass (OAGB) in patients with morbid obesity. Eligible patients aged 18-65 years with BMI ≥35 kg/m² (non-Asian) or ≥32.5 kg/m² (Asian populations) who were candidates for primary OAGB were randomized 1:1 using a computer-generated randomization sequence with sequentially numbered, opaque sealed envelopes.
In the intervention (TSBL-based) group, total small bowel length (TSBL) was measured intraoperatively from the ligament of Treitz to the ileocecal valve, and BPLL was calculated as 0.35 × TSBL. In the control (BMI-based) group, BPLL was determined using standard fixed lengths based on BMI category (150 cm, 180 cm, or 200 cm). All other surgical steps were identical between groups.
The primary outcome is percentage excess weight loss (%EWL) assessed longitudinally at baseline, 3, 6, and 12 months. Secondary outcomes include percentage total weight loss (%TWL), BMI, BMI loss, improvement of obesity-related comorbidities, and postoperative complications graded using the Clavien-Dindo classification. Statistical analysis uses linear mixed models to evaluate effects of group, time, and group-by-time interaction.
Because blinding of patients and surgeons was not feasible given the nature of the surgical intervention, outcome assessment relied on objective anthropometric and clinical measures. This record reflects a planned interim analysis conducted on the first 75 of a planned total of 100 enrolled patients, with 51 patients having completed 12-month follow-up at the time of this analysis.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| TSBL-Based Group | Experimental | Procedure: TSBL-based biliopancreatic limb length determinationBiliopancreatic limb length (BPL) individualized based on intraoperatively measured total small bowel length (TSBL), calculated as BPL = 0.35 × TSBL. |
| BMI-Based Group | Active comparator | Procedure: BMI-based biliopancreatic limb length determinationBiliopancreatic limb length (BPL) determined using standard fixed lengths based on BMI category: 150 cm for BMI 35-39.9, 180 cm for BMI 40-49.9, 200 cm for BMI ≥50. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Age between 18 and 65 years
- BMI ≥35 kg/m² in non-Asian populations or ≥32.5 kg/m² in Asian populations
- Presence or absence of metabolic comorbidities (including type 2 diabetes, hypertension, and dyslipidaemia)
- Eligibility for primary one-anastomosis gastric bypass (OAGB)
- Provision of written informed consent
Key exclusion criteria (9 listed)
- BMI below the defined thresholds
- Severe decompensated cardiac, pulmonary, hepatic, or renal disease
- Acute inflammatory conditions
- Active gastric or duodenal ulcer
- Psychiatric disorders or substance abuse
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TSBL-based biliopancreatic limb length determinationBiliopancreatic limb length individualized intraoperatively based on measured total small bowel length (TSBL), calculated as BPL = 0.35 × TSBL, prior to laparoscopic one-anastomosis gastric bypass. | Procedure or surgery | TSBL-Based Group |
| BMI-based biliopancreatic limb length determinationBiliopancreatic limb length determined using standard fixed lengths based on preoperative BMI category (150 cm, 180 cm, or 200 cm), prior to laparoscopic one-anastomosis gastric bypass. | Procedure or surgery | BMI-Based Group |
Primary outcome
Percentage of Excess Weight Loss (%EWL)
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
EWL defined as the proportion of weight loss relative to excess baseline weight, with ideal body weight defined as BMI 25 kg/m². Assessed longitudinally over time using linear mixed models.
5 secondary outcomes
Percentage of Total Weight Loss (%TWL)
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
BMI Change
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
BMI Loss (BMIL)
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
Improvement in Obesity-Related Comorbidities
Time frame: 12 months post-surgery
Postoperative Complications
Time frame: 12 months post-surgery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Sep 2026.
- Individual participant dataSharing planned: Yes. Individual participant data underlying the results reported in this article, after deidentification, may be shared with researchers upon reasonable request.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing TSBL-based biliopancreatic limb length determination and BMI-based biliopancreatic limb length determination in people with Morbid Obesity and Obesity, run by National Scientific Center of Surgery named after A.N.Syzganov at 1 site in Kazakhstan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 1 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Kazakhstan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Nurbol Orynbassar (+77474528797, nurbolorynbassar@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of Excess Weight Loss (%EWL) (time frame: Baseline, 3 months, 6 months, and 12 months post-surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Sep 2026; AzTrials last refreshed its copy on 26 Oct 2026.