Are there common back problems after bariatric surgery?

Depends. Not that I am aware of; most patients experience some adjustment to there new way of eating; and some post-op scarring but i would expect as weight loss occurs that back pains resolve. Best to as this question to those who have undergone the procedure; or to those who perform the procedure routinely. If i hear anything different i'll 're-tap'. Cheers!
Not really. If anything, most patients find relief of back pain after significant weight loss. Many patients increase their physical activity and exercise helps, as well.
Back gets better. Actually, with successful Bariatric surgery and weight loss, back problems tend to improve. The spine has less weight to support, and the exaggerated curvature associated with obesity tends to lessen providing more of a mechanical advantage in regards to your upright posture.
Usually better back. Most patients have much improved back symptoms. However, a herniated disc will usually remain a problem. In many cases, a surgically correctable cause for back pain becomes more reasonable after the weight loss.