Is insertion or replacement of a neurostimulator, such as the Enterra device, medically indicated for a patient with idiopathic gastroparesis who has not responded to conservative care and has refractory nausea and vomiting?

Gastric Electrical Stimulation (Enterra Device) is Medically Indicated for This Patient

This 38-year-old female with idiopathic gastroparesis meets criteria for gastric electrical stimulation (code 64590) based on documented very severe delayed gastric emptying (grade 4), refractory daily nausea and vomiting despite extensive conservative management, absence of mechanical obstruction, and failure of multiple therapeutic interventions including dietary modifications, prokinetic agents, and pyloric botulinum toxin injections. 1

Key Criteria Met

Documented Gastroparesis with Severe Delay

• Very severely delayed gastric emptying (grade 4) on gastric emptying study (8/29/25) with 79% retention at 4 hours confirms the diagnosis beyond question 1
• No mechanical gastric obstruction documented on multiple upper endoscopies and CT imaging 1

Refractory Symptoms Despite Adequate Conservative Management

The patient has exhausted appropriate medical therapy over an extended period (>18 months), which is the critical threshold for GES consideration 1:

• Prokinetic trials: Prucalopride (metoclopramide equivalent) with initial benefit but loss of efficacy even at increased doses 2
• Antiemetic therapy: Ondansetron (5-HT3 antagonist) used regularly with only partial benefit 2
• Dietary modifications: Small particle-size, low-fat diet management 1
• Pyloric-directed therapy: Three botulinum toxin injections (4/2024,1/2025,5/2025) with temporary benefit but recurrent symptom regression 1
• Surgical intervention: G-POEM procedure (10/2024) with no symptomatic improvement 1

Daily Refractory Nausea and Vomiting

• Most bothersome symptoms are nausea and vomiting experienced daily, which are the primary indications for GES 1
• Patient requires multiple daily interventions (alcohol pads, humming, wristbands, Zofran, Alka-Seltzer) just to maintain marginal symptom control 1

Critical Contraindications Assessment

Absence of Contraindications

The patient does NOT have contraindications that would preclude GES 1:

• No opioid use documented - this is an absolute contraindication to GES 1
• Abdominal pain is NOT the predominant symptom - nausea and vomiting are clearly the primary complaints 1
• Relatively shorter symptom duration (approximately 18 months of severe symptoms) predicts better response than prolonged intractable symptoms 1

Evidence Supporting Medical Necessity

FDA Approval and Guideline Support

• GES (Enterra Therapy) received FDA approval in 2000 specifically for drug-refractory nausea and vomiting due to gastroparesis 1
• The American Gastroenterological Association (2022) states: "GES could be an option for gastroparesis patients with refractory/intractable nausea and vomiting who have failed standard therapy, are not on opioids, and do not have abdominal pain as the predominant symptom" 1

Expected Clinical Outcomes

GES improves refractory nausea and vomiting in patients with gastroparesis and may improve glycemic control, nutritional status, and quality of life, while reducing hospitalizations and medication use 1:

• 75% of patients show symptomatic improvement with GES 3
• 43% achieve at least moderate improvement 3
• Nausea, loss of appetite, and early satiety respond best to GES 3
• Significant improvements in gastrointestinal-specific symptom scores and social functioning 4

Idiopathic vs Diabetic Gastroparesis

While diabetic gastroparesis may show superior response to GES compared to idiopathic gastroparesis, both etiologies demonstrate clinically meaningful benefit 1, 3:

• This patient has idiopathic gastroparesis, which still shows 75% response rate in clinical series 3
• The controversy regarding differential response should not preclude offering GES to appropriate idiopathic gastroparesis patients 1

Important Clinical Considerations

Temporary Stimulation Trial

If available, temporary electrical stimulation should be offered to predict response to permanent GES 1. However, unavailability of temporary stimulation should not preclude permanent device placement in patients meeting all other criteria.

Mechanism and Expectations

• GES does NOT accelerate gastric emptying - its mechanism involves neuromodulation of gastric pacemaker, sensory afferents, and other pathways 1
• Patients should understand that symptom improvement, not normalization of gastric emptying, is the therapeutic goal 1

Surgical Considerations

• The device can be safely placed via laparoscopic, robotic, or hybrid techniques 4, 5
• Postoperative morbidity is low (2% immediate, 7% long-term including device extrusion) 4
• Device adjustments post-implantation are necessary to optimize symptom control 4

Common Pitfalls to Avoid

Do Not Delay GES for Additional Botulinum Toxin Injections

Available data argue against continued use of botulinum toxin in refractory gastroparesis 1. This patient has already undergone three injections with diminishing returns - further injections would delay definitive therapy without evidence of benefit.

Ensure No Concurrent Opioid Use

Opioid use is an absolute contraindication to GES 1. Verify the patient is not taking any opioid medications, as they further delay gastric emptying and predict poor GES response.

Confirm Pain is Not the Predominant Symptom

Persistent abdominal pain is not an indication for GES 1. This patient's primary symptoms are clearly nausea and vomiting, making her an appropriate candidate.

Document Failure of Adequate Medical Therapy

The patient has documented trials of appropriate prokinetic agents (prucalopride/metoclopramide equivalent) and antiemetics (ondansetron) for adequate duration 1, 2. This documentation is essential for authorization.