Endoscopic augmentation of the lower oesophageal sphincter using hydrogel implants for the treatment of gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GORD) is caused by failure of the sphincter mechanism at the lower end of the oesophagus. It is commonly associated with hiatus hernia.

Symptoms of GORD include heartburn and retrosternal chest pain, regurgitation, waterbrash, respiratory symptoms, dysphagia and odynophagia (painful swallowing).

Mild symptoms of GORD can be managed with lifestyle modification and pharmacological therapy, which are effective in most patients. However, endoluminal gastroplication or antireflux surgery may be required for those with refractory symptoms or persistent oesophagitis.

The procedure is usually carried out under sedation on an outpatient basis. The aim is to augment the lower oesophageal sphincter mechanism by implantation of one or more prostheses. An endoscope and implant delivery mechanism (comprising a needle, trocar, dilator and delivery sheath) are inserted into an overtube – a tubular device with a shelf or notch near its tip. The overtube is guided to the gastro-oesophageal junction and suction applied, pulling a fold of the oesophageal wall into the shelf of the overtube. Saline is injected into this fold to create a space within the submucosa, and a hydrogel prosthesis is implanted. Suction is released and the overtube is rotated to the next location on the oesophageal wall. The prosthesis absorbs water and expands fully within 24 hours, bulking out the oesophageal wall.

In one case series (n=69), GORD/heartburn-related quality-of-life (GORD-HRQL) scores improved significantly, from 24 at baseline (n=64) to 5 at 6 months (n=53; p<0.05). Regurgitation scores also improved, from 16 at baseline (n=55) to 2 at 6 months (n=49; p<0.05). Physical aspects of quality of life (as measured by the SF‑36 Health Survey) improved significantly over 6 months (from 43 at baseline [n=60] to 52 at 6 months [n=57]; p<0.05), but the mental component of quality of life did not change significantly (from 49 at baseline [n=60] to 50 at 6 months [n=57]).

A case series of nine patients also reported improvement in mean GORD‑HRQL score from 35.5 at baseline to 9.4 at 6‑month follow-up (p<0.01).

In the case series of 69 patients oesophagitis was reported to be present at baseline in 58% of patients (39 out of 67) and at 6 months in 32% (17 out of 53).

In the case series of nine patients, acid exposure time of the distal oesophagus decreased in all patients but only reached normal levels (defined as below pH 4 for less than 4% of the time) in three. In the case series of 69 patients, acid exposure data were available for 45 patients. Only 40% of these (18 out of 45) had a normal pH level (using the same definition as above) at 6 months. For more details, see the overview.

The Specialist Advisers are uncertain whether the procedure has a long-lasting effect. They commented that few patients have shown a sustained reduction in objective measures of GORD, such as oesophageal acid exposure, after the procedure.

The case series of 69 patients reported safety outcomes. One patient's pharynx was perforated during overtube insertion, requiring a week of inpatient care, but surgical intervention was not required. In this case series the most common complication reported was erosion of the prosthesis into the oesophagus which occurred in 22% (15 out of 67) of patients by 6 months. For more details, see the overview.

The Specialist Advisers listed potential complications as pharyngeal perforation, mucosal erosion and migration of the device.