An interventional study of TSBL-based biliopancreatic limb length determination and BMI-based biliopancreatic limb length determination in Morbid Obesity and Obesity, sponsored by National Scientific Center of Surgery named after A.N.Syzganov. Recruiting at 1 site in Kazakhstan. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-01.
Sponsored by National Scientific Center of Surgery named after A.N.Syzganov · Not applicable, Interventional, and Treatment
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.
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.
941 studies on the registry are indexed under Obesity, Morbid; 163 are open to participants now.
This study's planned enrollment of 100 is above the median of 62 across 602 interventional studies indexed under Obesity, Morbid.
Browse Obesity, Morbid studies →This is the only study on the registry with National Scientific Center of Surgery named after A.N.Syzganov as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biliopancreatic limb length (BPL) individualized based on intraoperatively measured total small bowel length (TSBL), calculated as BPL = 0.35 × TSBL.
Procedure: TSBL-based biliopancreatic limb length determination
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.
Procedure: BMI-based biliopancreatic limb length determination
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.
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.
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.
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
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.
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
BMI Change
Change in body mass index (BMI, kg/m²) from baseline over time.
Time frame: Baseline, 3 months, 6 months, and 12 months post-surgery
BMI Loss (BMIL)
Reduction in BMI from baseline, expressed as BMI loss (BMIL).
Time frame: 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.
Time frame: 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.
Time frame: 12 months post-surgery
Plan to share: Yes — Individual participant data underlying the results reported in this article, after deidentification, may be shared with researchers upon reasonable request.
Supporting information: Study protocol
Time frame: Data will be available beginning 3 months after article publication, with no defined end date, for researchers who provide a methodologically sound proposal.
Access criteria: Data will be available to researchers who provide a methodologically sound proposal, upon reasonable request to the corresponding author (Nurbol Orynbassar, nurbolorynbassar@gmail.com).
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.