Gastric Electrical Stimulation With Enterra for Drug-resistant Gastroparesis

Nv G Jayanthi, MD FRCS, Sp L Dexter, MD FRCS, Ai Sarela, MD FRCS. Department of Upper Gastrointestinal, Metabolic & Bariatric Surgery, St James’s University Hospital, Leeds, UK

Introduction: Drug-resistant gastroparesis is a debilitating condition. Several clinical studies have demonstrated that most, but not all, patients get significant relief from vomiting by gastric electrical stimulation (GES) with the Enterra^TM device (Medtronic). Enterra^TM therapy has been approved by the U.S. Food & Drug Administration on a humanitarian device exemption basis. Selection criteria for Enterra^TM therapy remain uncertain and trial of temporary GES may be of predictive value. We commenced our Enterra^TM programme in May 2008, with a policy of routine temporary GES trial, and present our early results.

Patients & Methods: Consecutive patients referred to a specialist upper gastrointestinal surgery unit, at a university hospital in the UK, between May 2008 and June 2011, for consideration of Enterra^TM therapy were identified from a prospectively-maintained database. Patients were referred by gastroenterologists, who believed that medical therapy had been exhausted. The diagnosis of gastroparesis was confirmed and the extent of gastric emptying was measured by a radionuclide-labelled meal and gastric scintigraphy. Clinically suitable patients underwent temporary GES, by an endoscopically-placed electrode. A gastroparesis cardinal symptom index diary was used to evaluate clinical benefit and select patients for permanent Enterra^TM therapy. The permanent device was implanted laparoscopically, with electrodes placed in the gastric wall at 9cm and 10cm proximal to pylorus along the lesser and greater curvature, respectively. Position of the electrodes was confirmed by on-table endoscopy. A previously published energy algorithm (Abidi, 2006) was used to modify the stimulation program during follow-up.

Results: A total of 63 patients with medical therapy-resistant gastroparesis were referred for Enterra^TM therapy during the study period. One patient died whilst awaiting transfer. To date, 42 patients have undergone temporary GES. There was clinically-meaningful symptom improvement in 31 patients (74%), who were selected for permanent placement of the Enterra^TM device. Laparoscopic placement of the permanent device has been completed in 29 patients. 22 patients have been assessed following permanent Enterra^TM therapy. At a median follow up of 31 weeks, clinically-significant symptomatic improvement was noted in 16 patients (73%). One patient has required placement of a feeding jejunostomy following failure of symptom resolution despite sequential increase in energy delivery.

Conclusions: Gastric electrical stimulation with Enterra^TM provides clinically significant symptom resolution in the majority of patients with severe gastroparesis. Patient-selection for implantation of a permanent Enterra^TM device is aided by a prior trial temporary GES, with an endoscopically-placed electrode. However, despite use of selection measures, patients need to be cautioned about uncertainty of the ultimate outcome.