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Kitamura et al. Mini-invasive Surg 2022;6:44 https://dx.doi.org/10.20517/2574-1225.2022.27 Page 3 of 9

The device is implanted laparoscopically under general anesthesia. In contrast to laparoscopic
fundoplication, the gastric fundus and short gastric arteries are not mobilized or transected. Hiatal
dissection is minimized, and the phreno-esophageal ligament and hepatic branch of the vagus nerve are
preserved, if possible [5,14] . The gastrohepatic ligament remains largely intact, and the posterior and greater
curvature of the stomach is not extensively mobilized. The plane between the vagal nerves and the
esophagus is entered, and the esophagus is circumferentially dissected, then measured. The appropriately
sized MSA device is then introduced in this location and the opposing ends are clasped. Postoperatively, a
chest film is performed to check the correct placement of the device. Patients are instructed to start a soft
diet immediately after and patients are typically discharged within 24 h [5,15] .

Laparoscopic fundoplication
Laparoscopic Nissen Fundoplication has been the gold standard for anti-reflux surgery. First described by
Dr. Rudolph Nissen in 1955, the procedure has undergone several modifications over time, and technique
may vary between surgeon and institution today. The aim is to augment the pressure of the LES by
mobilizing the gastric fundus and creating a short and floppy 360-degree wrap around the gastroesophageal
junction (GEJ). Typically, this is done over a bougie to prevent narrowing. The mediastinal esophagus is
mobilized to ensure at least 2-3 cm of the tension-free intra-abdominal esophagus and the hiatus is repaired.
Although the 360-degree Nissen fundoplication has been the gold standard, partial wraps are becoming
increasingly popular, with recent data supporting lower rates of postoperative dysphagia, gas bloat
[7]
symptoms, and equivalent long-term patient satisfaction and reflux control .
OUTCOMES
MSA safety and efficacy
In the treatment of uncomplicated reflux disease, MSA is safe and significantly more effective than maximal
[16]
medical treatment alone . The CALIBER study is a randomized control trial, which demonstrated the
superiority of MSA over twice daily PPI use at 12 months in terms of patient satisfaction, regurgitation
symptoms, bloating, flatulence, and dysphagia .
[17]
Current data on MSA outcomes are encouraging, however, limited to five years. Patients have reliably
reported significant improvement in satisfaction scores, PPI cessation, and maintained the ability to belch
and vomit if needed. Mild dysphagia may occur immediately postoperatively but is usually self-limiting.
Severe dysphagia requiring endoscopic dilation or reoperation is rare and does not occur more frequently
than after surgical wraps. There have been sporadic reports of device erosion. Most recently, an erosion rate
of 0.3% was reported at a 5-year follow-up. Thus far, all eroded devices were able to be removed safely via
laparoscopic or endoscopic approaches with unremarkable postoperative courses [18,19] .

Comparative studies
Initial short-term comparative studies of MSA and LF excluded patients with complicated GERD from the
MSA arm - that is, the prevalence of patients with a hiatal hernia > 3 cm, grade C or D esophagitis, BE, or
2
BMI above 35 kg/m were higher in LF groups. However, 6 months after implantation, significant and
similar improvements were seen in both MSA and LF patients for GERD-health-related quality of life
(GERD-HRQL) scores and DeMeester scores. MSA patients report fewer gas bloat symptoms and felt they
were capable of belching more than the LF group [13,20,21] .

After one year, Riegler et al. compared 202 MSA and 47 LF patients and reported similar improvement in
GERD-HQRL scores between groups . Despite patients in the LF cohort having larger hiatal hernias and a
[22]
higher prevalence of BE, both groups reported similar improvements in regurgitation and PPI cessation.
However, MSA patients had less gas bloat (10% vs. 31.9%; P < 0.001) symptoms, and preserved ability to