Peroral endoscopic myotomy (POEM) is an innovative, minimally invasive procedure for achalasia and other oesophageal muscle disorders. Achalasia has an annual incidence of approximately 1.5-2 per 100,000 people in the UK, while its prevalence is estimated at 27 per 100,000, and can lead to debilitating malnutrition and poor quality of life if left untreated. Learn more from Dr Jason Dunn, consultant gastroenterologist at St Thomas’ Hospital, as he discusses our private POEM service for achalasia patients.

Physiological assessment to guide POEM 

Guy’s and St Thomas’ hospitals are home to the gastrointestinal department’s physiology laboratory, one of the busiest oesophageal physiology laboratories in the world with over 1,000 patients diagnosed each year. 

In some patients with dysphagia, a diagnosis of achalasia is made using high-resolution manometry. This is a very safe and effective test for measuring the oesophageal pressure wave and relaxation of the lower valve. Recently, our specialists have introduced the EndoFLIP procedure, which can act as a complementary test to measure the distensibility of the oesophagus in real time in endoscopy. 

Our expert team carries this out at the beginning of the POEM procedure. “In terms of diagnosis, we use the EndoFLIP to get a measurement of how severe the patient’s achalasia is,” explains Dr Dunn. “Then, we can use that figure to tailor the myotomy, which essentially makes the procedure a more personalised POEM. Our recent work has shown that a good EndoFLIP measurement at the end of the procedure correlates well with symptomatic improvement.” 

The EsoFLIP (a balloon catheter) may also be used to dilate the lower oesophageal sphincter, ensuring it opens adequately without over-stretching. This is often used in patients who cannot tolerate the anaesthetic for POEM. 

How POEM works and why patients benefit 

The POEM procedure is carried out under general anaesthetic and takes around 2 hours to complete. An endoscope is passed into the patient’s mouth, before our interventional endoscopist makes a small cut in the lining of the lower oesophagus. A liquid solution is injected into this small incision, and the endoscope can then be passed through to divide the lining from the muscle. 

The endoscopist cuts the muscle fibres in the oesophageal sphincter, which allows food to pass down into the upper stomach, instead of remaining in the oesophagus or being regurgitated. Once this part of the procedure is finished, the incision is closed with clips to keep the oesophageal lining together while it heals. There are no external scars. 

Patients are then free to consume liquids and often feel the benefit of the surgery from their first sip of water upon waking from the procedure. Our team typically keeps POEM patients under observation for 24–48 hours and on a liquid diet for the first week to allow the oesophageal lining to heal, before reintroducing solid foods. 

Most achalasia patients are good candidates for POEM, although in patients aged over 75, Botox may be a more suitable treatment. “For patients in this age group, due to the general anaesthetic required, the risk benefit ratio for POEM doesn’t always add up,” explains Dr Dunn. “POEM is also considered for patients who have had previous surgery for achalasia that has not provided long term success, or those who have not responded to prior dilatation.” Our team can also offer dilatation with the EsoFLIP as a standalone treatment, which is a viable alternative to POEM for some patients.

A commitment to holistic patient care 

Often, patients who have been living with achalasia for an extended period suffer from psychological impacts of the condition too. “They often have food avoidance problems, as well as social eating avoidance,” explains Dr Dunn. “We work with dietitians at St Thomas’ Hospital to provide holistic care, especially as our achalasia patients regularly come in undernourished or, in some cases, malnourished.” 

Ensuring that patients are cared for beyond their physical achalasia symptoms is a priority for our gastroenterology team and, with consultants specialising in psychological, nutritional and gastrointestinal care, we’re proud of the holistic approach our patients benefit from. 

Clinical studies show that POEM provides long-term symptom relief in the vast majority of patients (90% clinical response at 1 year), making it an effective and durable option for achalasia management. “Private care is a good option for achalasia patients as they can get a faster diagnosis, which in turn may lead to a better treatment outcome and recovery experience,” says Dr Dunn.

Expertise behind minimally invasive oesophageal care 

Dr Dunn has been a consultant gastroenterologist since 2011 and has focused mainly on oesophageal care in that time. With specific expertise in Barrett’s oesophagus and minimally invasive ways to treat cancer, Dr Dunn has been the clinical lead for endoscopy at Guy’s and St Thomas’ hospitals and chairman of the oesophagio-gastric cancer group for southeast London. 

“St Thomas’ Hospital is one of the biggest centres in the UK for resectional work for early cancer, giving us a skillset where we’re very used to dealing with complex cases,” explains Dr Dunn. “We’ve created a tertiary referral base for the complex oesophageal work that stretches out to the whole of the southeast, so we have a great understanding with gastroenterologists around the region regarding oesophageal specialist care, and we receive multiple referrals.” 

As well as a dedicated private POEM service, St Thomas’ gastroenterology department is home to a busy NHS practice too. “This is crucial as it means our gastro nurses and anaesthetists have a lot of experience with the POEM procedure, offering exceptional wraparound care,” says Dr Dunn.

When to refer 

Patients should be referred to our consultant gastroenterologists if they have dysphagia and often feel that their oesophagus is filling up when eating and drinking. Some patients who end up having the POEM procedure also experience regurgitation of undigested food, a spasm-like chest pain, heartburn and weight loss. 

While the NHS dysphagia referral target is 2 weeks for patients aged over 50, younger patients often face longer wait times due to cancer rarely being suspected in this age group. However, dysphagia in younger patients can often occur as a result of achalasia, requiring prompt treatment, and referral should therefore not be delayed. 

Reviewed regularly to reflect clinical best practice
Last reviewed: 26 February 2026