Vagus nerve obesity treatment, specifically vagal nerve blockade (VBLOC), is an emerging approach that uses electrical impulses to modulate appetite and satiety signals. Unlike traditional bariatric surgery, which physically alters the digestive system, VBLOC involves implanting a device that delivers intermittent electrical pulses to the vagal trunks near the gastro-oesophageal junction. Whilst the therapy has regulatory approval in some jurisdictions, clinical evidence shows modest weight loss outcomes compared to established surgical procedures. In the UK, NICE advises that the procedure should only be used with special arrangements for clinical governance and research, and it is not routinely commissioned by the NHS. This article examines the mechanism, evidence, eligibility criteria, risks, and availability of vagal nerve blockade for obesity treatment.

What Is Vagal Nerve Blockade for Obesity?

Vagal nerve blockade (VBLOC) for obesity is an emerging therapeutic approach that uses electrical impulses to modulate the vagus nerve, which plays a role in regulating appetite, satiety, and gastrointestinal function. The vagus nerve is the tenth cranial nerve and forms part of the parasympathetic nervous system, transmitting signals between the brain and various organs including the stomach and intestines.

This therapy is distinct from cervical vagus nerve stimulation (VNS) used for epilepsy or depression. VBLOC involves implanting a small device, similar to a cardiac pacemaker, which delivers intermittent electrical pulses to the vagal trunks near the gastro-oesophageal junction. The most studied system is the Maestro® Rechargeable System (also known as vBloc® Therapy), which uses a neuroregulator implanted in the abdominal wall with leads attached to the anterior and posterior vagal trunks. The device is programmed by clinicians and delivers therapy in cycles; patients are responsible for daily charging using an external controller worn against the skin.

Mechanism of action: VBLOC aims to interrupt neural communication pathways involved in hunger and satiety. By modulating vagal nerve activity at the gastro-oesophageal junction, the therapy is intended to reduce appetite and increase feelings of fullness. The precise effects on gastric emptying and satiety vary between individuals and are not uniform across studies. This differs from traditional bariatric surgery, which physically alters the anatomy of the digestive system.

The procedure is performed laparoscopically under general anaesthesia, typically requiring an overnight hospital stay. Patients must charge the device daily, and therapy settings are adjusted by the clinical team based on individual response and tolerability.

Clinical Evidence and Effectiveness

The clinical evidence for vagal nerve blockade in obesity treatment remains limited but evolving. The pivotal ReCharge trial, a randomised controlled study conducted in the United States, demonstrated modest weight loss outcomes. At 12 months, participants with the active VBLOC device achieved approximately 9% total body weight loss (corresponding to roughly 25% excess weight loss), compared to approximately 6% total body weight loss in the control group—a difference that, whilst statistically significant, was relatively small in absolute terms.

Longer-term data from the ReCharge trial extension showed that at five years, patients maintained an average total body weight loss of approximately 8%, with corresponding excess weight loss of around 20%. However, it is important to note that these results are considerably more modest than those typically achieved with established bariatric surgical procedures such as gastric bypass (50–70% excess weight loss) or sleeve gastrectomy (40–50% excess weight loss).

Key findings from clinical studies include:

• Weight loss tends to be gradual and variable between individuals

• Some patients experience modest improvements in obesity-related comorbidities, including small reductions in HbA1c levels in those with type 2 diabetes, though data are limited

• The therapy appears most effective when combined with lifestyle modifications, including dietary changes and increased physical activity

• Response rates vary considerably, with some patients achieving minimal weight loss

In the United States, the Food and Drug Administration (FDA) approved the Maestro system for adults with a body mass index (BMI) of 40–45 kg/m² or 35–39.9 kg/m² with at least one obesity-related comorbidity, who have failed to achieve weight loss through conventional methods. In the UK and Europe, the device holds CE marking (now transitioning to UKCA marking under UK regulations), but NICE has issued Interventional Procedures Guidance advising that the procedure should only be used with special arrangements for clinical governance, consent, and audit or research. The therapy is not routinely commissioned within the NHS. Further long-term studies are needed to establish optimal patient selection criteria and to compare effectiveness against other weight management interventions.

Who Is Eligible for Vagal Nerve Blockade?

Eligibility criteria for vagal nerve blockade therapy are specific and based on regulatory approvals, device labelling, and clinical trial parameters. The treatment is not suitable for all individuals with obesity and requires careful patient selection to optimise outcomes and minimise risks.

General eligibility criteria (based on FDA labelling and clinical trial protocols) include:

• BMI requirements: Adults with a BMI of 40–45 kg/m² or 35–39.9 kg/m² with at least one obesity-related comorbidity (such as type 2 diabetes, hypertension, or dyslipidaemia)

• Age: Typically between 18 and 65 years

• Previous weight loss attempts: Documented failure to achieve or maintain clinically significant weight loss through supervised diet, exercise, and behavioural modification programmes

• Psychological assessment: Patients must undergo psychological evaluation to ensure they have realistic expectations, can commit to long-term lifestyle changes, and can adhere to daily device charging requirements

• Absence of contraindications: No history of certain gastrointestinal conditions, previous gastric or oesophageal surgery, or conditions that would make laparoscopic surgery unsafe

Specific contraindications (per device labelling) typically include:

• Cirrhosis or portal hypertension

• Significant hiatus hernia or gastro-oesophageal reflux disease requiring surgical intervention

• Previous gastric, oesophageal, or bariatric surgery

• Conditions requiring chronic anticoagulation that cannot be safely interrupted

• Pregnancy or plans to become pregnant (device should be switched off during pregnancy)

• Inability or unwillingness to comply with device charging and follow-up requirements

In the UK, vagal nerve blockade is not routinely commissioned by the NHS. Any use should be within specialist centres, typically under research protocols or special clinical governance arrangements as advised by NICE. Patients considering this therapy should first be referred to NHS Tier 3 weight management services for comprehensive multidisciplinary assessment. A multidisciplinary team involving bariatric physicians, surgeons, dietitians, and psychologists is essential before proceeding with any intervention. It is important to discuss all available treatment options, including established bariatric surgical procedures and newer pharmacological therapies, with a specialist obesity service.

Potential Risks and Side Effects

As with any surgical intervention, vagal nerve blockade for obesity carries both procedural risks and device-related adverse effects. Patients should be fully informed of these potential complications before consenting to treatment.

Surgical and procedural risks include:

• Infection at the implant site or within the abdominal cavity

• Bleeding or haematoma formation

• Injury to surrounding organs during laparoscopic placement

• Anaesthetic complications

• Need for revision surgery if leads become dislodged or the device malfunctions

• Scarring at incision sites

Device-related adverse effects reported in clinical trials include:

• Gastrointestinal symptoms: Nausea, vomiting, dyspepsia, abdominal pain, belching, and eructation are among the most commonly reported side effects. These symptoms are often most pronounced during the initial adjustment period and tend to improve over time

• Dysphagia: Difficulty swallowing has been reported in some patients

• Heartburn and gastro-oesophageal reflux: Some patients experience worsening reflux symptoms

• Pain at the neuroregulator site: Discomfort where the device is implanted may persist for weeks or months

Most adverse effects are mild to moderate in severity and tend to improve as patients adapt to the therapy. However, in clinical trials, a small proportion of patients required device explantation due to intolerable side effects or complications.

Important safety considerations:

• The device is MR-conditional: MRI scans may only be performed under specific conditions defined in the device instructions for use (IFU), including permitted field strengths and sequences. The device must be managed according to the manufacturer's MRI protocol

• Electrosurgical diathermy and electrocautery must be used with caution during any subsequent surgery; the clinical team must follow device-specific precautions

• Patients with other implanted electronic devices (e.g., cardiac pacemakers, defibrillators) require careful assessment for potential interactions

• Patients must charge the device daily; failure to do so may result in reduced effectiveness

• The long-term effects of chronic vagal nerve modulation remain under investigation

Reporting side effects: If you experience any side effects, talk to your doctor or specialist nurse. You can also report suspected side effects directly via the Yellow Card Scheme at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. Reporting helps provide more information on the safety of this device.

When to seek medical attention: Contact your healthcare provider immediately if you experience severe abdominal pain, persistent vomiting, signs of infection (fever, redness, or discharge at the implant site), difficulty swallowing liquids, or any sudden change in symptoms. Regular follow-up with the implanting centre is essential for device monitoring and adjustment.

Availability and Access in the UK

Access to vagal nerve blockade for obesity treatment in the UK is currently very limited, and the therapy is not routinely available through the NHS. Unlike established bariatric surgical procedures such as gastric bypass or sleeve gastrectomy, VBLOC for obesity has not been widely adopted in UK clinical practice.

Current status in the UK:

NICE has issued Interventional Procedures Guidance on laparoscopic electrical stimulation of the vagus nerve for obesity, advising that the procedure should only be used with special arrangements for clinical governance, consent, and audit or research. Without a positive NICE technology appraisal or routine commissioning recommendation, NHS funding of this intervention is unlikely, and most Integrated Care Boards do not commission VBLOC for obesity. The therapy is therefore primarily available through private healthcare providers. Indicative private costs may range from £15,000 to £25,000, including the device, surgical implantation, and initial follow-up care, though prices vary widely. Patients considering private treatment should request itemised quotes and detailed information about the provider's outcomes and complication rates.

The Medicines and Healthcare products Regulatory Agency (MHRA) regulates medical devices in the UK. VBLOC systems previously approved under EU CE marking are transitioning to UKCA marking under UK regulations. However, the limited evidence base and modest weight loss outcomes compared to conventional bariatric surgery have restricted uptake.

Alternative options available on the NHS:

For individuals with obesity who meet eligibility criteria, the NHS offers several evidence-based interventions:

• Tier 3 weight management services: Multidisciplinary programmes including dietary advice, physical activity support, behavioural interventions, and psychological support

• Bariatric surgery: Gastric bypass, sleeve gastrectomy, or adjustable gastric banding for those with BMI ≥40 kg/m² (or ≥35 kg/m² with obesity-related comorbidities such as type 2 diabetes or high blood pressure) who have tried other weight loss methods. NICE guidance (CG189) provides detailed eligibility criteria

• Pharmacological treatments: Medications such as orlistat, and more recently, GLP-1 receptor agonists like semaglutide (Wegovy®) or tirzepatide for eligible patients, in line with NICE guidance

Seeking treatment: Patients interested in weight management should first consult their GP to discuss all available options. Referral to a specialist NHS Tier 3 weight management service is appropriate for comprehensive assessment and access to multidisciplinary support. Those considering private treatment for VBLOC should ensure the provider is registered with the Care Quality Commission (CQC) and that the multidisciplinary team includes experienced bariatric surgeons, physicians, dietitians, and psychologists. It is advisable to request detailed information about success rates, complication rates, long-term follow-up arrangements, and the provider's experience with the device before proceeding. Further information on NHS weight management and bariatric surgery pathways is available on the NHS website.

Frequently Asked Questions