Complications in bariatric surgery

Mervi Javanainen

Research output: ThesisDoctoral ThesisCollection of Articles


Since 1975, the prevalence of obesity has nearly tripled, and 39% of the world’s population is now overweight. Bariatric surgery has proven to be the most effective treatment for obesity and obesity-related diseases. Roux-en-Y gastric bypass (RYGB) is one the most popular and well-studied operation types worldwide. However, in recent years, the popularity of sleeve gastrectomy (SG) has risen rapidly, surpassing the RYGB. Bariatric surgery has proven to be safe; however, there is still limited information about some of the complication types. The complications that occur after bariatric surgery can be divided into early complications (under 30 days after the operation) and late ones (over 30 days after the operation); late complications can further be divided into surgical and non-surgical complications. This thesis consists of four different studies on the common complication types related to bariatric surgery. Study I analyses the relationship between bleeding/venous thromboembolic complications and different enoxaparin protocols, and Study II reviews the changes in pulmonary complications under different perioperative protocols. The last two studies compare late complications, vitamin deficiencies, and fractures between RYGB and SG operations. In Study IV, we also compare the number of fractures that occur after surgery to fractures in non-surgically treated patients. All the data from the patients were collected between 2007 and 2016 at Peijas Hospital, affiliated to Helsinki University Hospital. The patient characteristics and the data from the first two years were collected prospectively and later retrospectively. In addition to analyzing the patients who underwent operations, Study IV includes 199 non-surgically treated obese patients as a control group. In Studies I and II, the follow-up times were 30 days. In Study III, the follow-up time was two years, and, in Study IV, the follow-up time was at least six years. The results of Study I showed that enoxaparin was safest when administered in a 40-mg dose once a day. Study II revealed that, alongside avoiding the use of drains and urinary catheters, fast mobilization was favorable to prevent postoperative pneumonia and shorten the hospital stay. The last two studies compared RYGB to SG. It was observed that, compared to the SG patients, the RYGB patients had more late complications treated surgically or endoscopically. In Study IV, vitamin D, albumin, and B12 levels were at an acceptable level two years after either operation. It was shown that the bariatric patients had a higher risk of fractures compared to the non-surgically treated patients. Higher age, bariatric surgery, and lower body mass index (BMI) at the two-year control mark increased the risk of fracture after obesity treatment.
Original languageEnglish
  • Leivonen , Marja, Supervisor
  • Scheinin, Tom, Supervisor
  • Mustonen, Harri K, Supervisor
Place of PublicationHelsinki
Print ISBNs978-951-51-5221-3
Electronic ISBNs978-951-51-5222-0
Publication statusPublished - 2019
MoE publication typeG5 Doctoral dissertation (article)

Bibliographical note

M1 - 102 s. + liitteet

Fields of Science

  • Bariatric Surgery
  • +adverse effects
  • +methods
  • Postoperative Complications
  • Enoxaparin
  • +administration & dosage
  • Thromboembolism
  • +prevention & control
  • Age Factors
  • Avitaminosis
  • Gastric Bypass
  • 3126 Surgery, anesthesiology, intensive care, radiology

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