how to convince my neice to get VSG

You got some great answers here already, so I just want to address one thing.. with the RNY she will still have a strict vite and lab regimen, whether she realizes this or not.. the same with the DS, a few more vites, but still a strict vite & lab routine.. but a much better chance of having a great outcome long term vs the RNY..

I won't push anyone in any direction, but the best suggestion I can make is press her to get on OH and read everything! Maybe pass along this transcript (below) to her. In my mind, there are two best surgeries out there- the VSG for those that really think they can maintain with restriction and a healthy diet only (all surgeries except the band, will make you lose the weight initially, the big issue is maintaining!) and the DS for those that need help maintaining.. stats do show, the higher the starting BMI, the harder it is to maintain long term.. factor in any metabolic issues, and what her real-life personality is.. know yourself is a biggie on this deal in choosing the right operation. There are exceptions to every study, but I won't argue with statistics..

Here's the transcript.. http://www.obesityhelp.com/forums/amos/4416773/quotDoes-the- Patient-Fail-the-Procedure-or-Does-the/ please make sure she's reading many of the med studies/peer reviewed studies out there.. so many of these seminars are one big sales pitch, and I know several folks who have had the RNY, one never even knew of the sleeve, and didn't have any idea of the real downsides of the RNY.. just went to a seminar or two, a couple classes, did no research on her own and just dove in. 

Perhaps you can get your niece to get a second opinion (second opinions are always a good idea on major surgery as a means of exploring options,) from another surgeon, preferrably one who also does the DS. This is not so much to promote the DS with her, though she sounds like a good candidate if her mind is behind it, but because it seems from reading many people's experiences here that a lot of the general bariatric surgeons are just getting into doing the VSG, so that any patient who presents challenges, such as high BMI or diabetes related issues, gets the RNY recommendation because that is the best that that surgeon can offer, and it is what he is most comfortable with. It seems that most of the DS qualified surgeons are more accepting of a patient's desire for a VSG since they have a better understanding of it, and they may not be so eager to perform a DS on a patient who may not be long term compliant. Having a surgeon with a somewhat different experience profile within the specialty makes for a good second opinion no matter which direction one chooses to go as you get a more complete view of the choices.

Another minor point (that may become major later on,) is that should the RNY or VSG not work for her and she has regain problems (which is a risk of any of these procedures, but particularly of the restrictive only procedures like the RNY and VSG, not to mention the bands,) the VSG is much easier to revise to a DS than an RNY - there are relatively few surgeons in the country who are really qualified to do RNY to DS revisions.

The juvenile arthritis stands out to me as a huge reason that she would not be a good candidate for RNY. Ask her what her plans are for medications when she can't take NSAIDS after she has the RNY. Ask her if she has discussed this with her rheumatologist - and if she hasn't, kindly suggest that she needs to!

I like califsleevin's suggestion to get a 2nd opinion from a surgeon who does the DS and the VSG. I think she'll get much better advice.