Caveats to Bariatric Surgery

This blog provides free general information for anyone who is seeking to understand more about the weight loss surgery, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.

Failures of weight loss

Bariatric surgery (sleeve gastrectomy or gastric bypass) is the most effective treatment for patients with morbid obesity (BMI >40) and those with obesity (BMI >35) with associated medical co-morbidities.

But still about 20% of patient experiences <50% excess weight loss (EWL) or experiences <20-25% total body weight loss (TBWL) in the 1 to 2 years post op follow up period, even in the gastric bypass group.

The inferior weight loss outcome may result in persisting cardio-vascular risk factors, medical co-morbidities, psychological conditions and impaired health related quality of life.

Predictors of lower weight loss after surgery may include:

  • Higher age group (slower metabolism, menopause/hormonal change, limited mobility/physical activities, etc)
  • Certain medical conditions (hypothyroidism, being on insulin, prednisolone, antidepressants, pain killers, etc)
  • Bad eating behaviours (emotional eating, grazing, alcohol addiction, etc)
  • Psychological conditions (personality disorder, PTSD, anxiety/depression, etc)
  • Higher pre-op BMI 
  • Previous failed weight loss attempts (slower metabolism, genetic/physiology factors)
  • Lesser amount of weight loss during the pre-op VLCD phase (physiology factors, compliance, etc)

However bear in mind that obesity is a chronic disease and almost all patients tend to regain weight from 2 years or more after initial surgery.

Long term outcomes

In the long term (10 years) after a sleeve gastrectomy, up to half or more (58%) of patients may develop gastro-oesophageal reflux disease (GERD).

  • Erosive oesophagitis, hiatus hernia and Barrett’s oesophagus may occur in 5% of these patients.

The Roux Y gastric bypass (RYGBP) is superior to the sleeve to decrease the risk for gastro-oesophageal reflux disease (GERD) (pre-op reflux symptoms decrease by 90%), erosive oesophagitis (84%) and regression of Barrett’s oesophagus (62%).

  • However with time after a gastric bypass, there may be cardia dilatation and elongation of the proximal gastric pouch, this may lead to loss of restriction and relapse of the reflux symptoms.
  • In some reports even after a RYGBP there may be up to 13% of erosive oesophagitis in the non symptomatic and 53% of symptomatic reflux patients.
  • In another study there is a report for erosive oesophagitis in about 75% after a sleeve and 22% after one anastomosis and Roux Y gastric bypass.

Hence it is important for patients to keep in touch and contact their surgeon for post follow gastroscopy check if there are reflux symptoms, which may be 5 years or more after sleeve or gastric bypass.

  • Revision surgery may be necessary for refractory symptoms, marginal ulcer, stricture, hiatus hernia, erosive oesophagitis, etc.
  • Revision surgery for weight regain is much easier to do in the sleeve gastrectomy group. In the RYGBP group it is much more difficult and the results are uncertain.

Pregnancy after sleeve gastrectomy

Most surgeon recommend/advise patients to wait 12-18months after a sleeve gastrectomy before getting pregnant. This allows time for dietary/behaviour change and adequate weight loss to be achieved in this critical period of time.

The sleeve is also much safer than the gastric bypass when the patient gets pregnant.

Some studies now showed that there are no differences in maternal and neonatal complications when pregnancy occurred less than 1 year after a sleeve gastrectomy. But obviously the time frame to achieve significant total body weight loss is much shortened.

After multiple pregnancies weight regain often happen as well as the risk for reflux or hiatus hernia.

  • Revision surgery is becoming more common for the younger female patients for weight regain and reflux years after initial sleeve gastrectomy.

Special cautionary note for patients who became pregnant after a bypass procedure. Please ask your GP to do the usual antenatal blood test and have the multivitamin supplements as recommended.

  • During pregnancy fetal growth and immunity require vitamin A, D and zinc. Brain and neurological development require thiamine (B1), iodine and omega 3 fatty acids.
  • Deficiencies in vitamin C, B9, B12, E, Zinc, Selenium and iron had been linked to preterm birth and deficiencies in vitamin B9 and B12 have a higher abortion rate.
  • Also if a bowel obstruction occurs during pregnancy, it is not possible to do a CT scan and very difficult to operate when the patient is pregnant.

Revision surgery after sleeve gastrectomy, OAGB and RYGBP

Laparoscopic sleeve gastrectomy is the most commonly performed primary bariatric surgery and probably will remain so in the near future.

  • The sleeve is still the most technically simple procedure with proven successful weight loss result and resolution of medical co-morbidities.
  • It is also the most versatile operation which allows revision surgery in the future as a planned second stage procedure or for unplanned (perhaps not unexpected) reflux and weight regain in the long term, 5 or 10 years post op or more ?

Revision surgery for acid reflux after a sleeve gastrectomy has been reported for up to 83% of patients.

  • However most surgeons/physician advocate that the first line of treatment for reflux is dietary modification and anti-acid medications, not necessarily rushing in to convert the sleeve to a Roux Y gastric bypass (RYGBP).

Revision surgery for alkaline/bile reflux after a One Anastomosis Gastric Bypass (Minibypass or OAGB) to RYGBP may be needed.

  • Some reported that this to be in 6.8% of the patients.

Revision surgery may be needed for inadequate weight loss after RYGBP. Despite good long term data on the durability and efficacy of the RYGBP, 15-20% of patients regain weight, maybe up to 20% of the weight they lost initially.

To re-iterate revision surgery after initial RYGBP is technically much more difficult to do and the weight loss results may be unsatisfactory, the risk and complications much higher than the primary procedure.

This is a complex topic and won’t discussed at length here. Options may include:

  • reduction of the pouch
  • narrowing of a wide stoma at the gastro-jejunostomy anastomosis
  • excision of gastro-gastric fistula
  • lengthening the Roux limb
  • conversion to SADI-S or BPD-DS
  • or perhaps the newer innovations in the future such as SAJI ?

Often there is not a single reason for weight regain after a RYGBP, restriction of the gastric pouch (to <35mls volume), narrowing of the stoma (to <1.5 or 2cm diameter) and may be an additional malabsorptive component is needed as well.

  • Lengthening of the BP or alimentary limbs (shorten the common channel to 75-150cm) may result in diarrhoea, malabsorption, protein-calorie malnutrition and adverse nutritional consequences.
  • Placing a band on the gastric pouch or narrowing the stoma size endoscopically has yet to report the efficacy of these procedures in the long term.
  • Conversion back to sleeve, SADI-S or BPD-DS is technically challenging with higher morbidity and mortality rates.

Single jejuno-ileal anastomosis (SAJI) is performed by anastomosis of the jejunum Roux limb (30cm distal to the gastro-jejunal anastomosis) to the ileum (300cm proximal to the ileo-caecal valve).

  • This is technically more simple than distalizing the RYGBP but may result in severe malabsorption side effects in the future.


Obesity is a chronic disease and almost all patients tend to regain some weight from 2 years or more after initial surgery.

Reflux symptoms are also common after a sleeve gastrectomy and one anastomosis gastric bypass. Reflux may also occur after Roux Y gastric bypass but much less common.  

Follow up gastroscopy check for hiatus hernia, erosive oesophagitis, Barrett’s oesophagus, bile reflux, marginal ulcer, anastomotic strictures, etc are necessary many years after initial surgery.  

With the number of primary bariatric operations and with longer follow up time, complications will occur and revision bariatric surgery will become a bigger part of the workload for bariatric surgeons in the future.