There's no way, short of not riding at all (not an option) to prevent all snowboarding injuries. Our beloved sport is loaded with potential hazards, always lurking, ready to jump up and smack you down, especially if you're driving to improve every time you strap in. Crashes are inevitable, but getting hurt doesn't have to be. Protective gear has become very refined and specialized for snowboarding in the past several years. It's grown smaller, lighter, more ergonomic and comfortable and is designed to protect against snowboard specific injuries.
A helmet is the most obvious protective device. It might not necessarily be the the protection you'll USE every day (unless you have a penchant for bashing your head) but it holds the biggest penalty for neglecting to wear it. You can survive and come back from sprains, broken bones, blown achilles tendons and most other physical disasters but a solid crack to the noggin, well, that could mean lights out for good.
Now almost any head protection is better than none but if you're going to wear one it's a good idea to use a helmet designed specifically for snowboarding. In the US these will carry an ASTM 2040 sticker or CE 1077 in Europe which indicates they have passed tests according to established snow-sports standards in each region. If you're thinking you can simply get double duty out of your skate helmet, be aware that many skate helmets offer only about 20% of the protection packed in a certified snowboard helmet. ASTM and CE certified lids are optimized to work consistently in cold weather, it is a winter sport after all, and offer protection from certain snowboard only impacts, like a back of the head edge strike as additional payment for a big skorp. How many stitches d'ya think that'll save…?
There's other gear that's handy and you'll more likely use every day, like wrist, elbow, hip, back, knee and shin guards, goggles, foot beds and mouth guards. Mouth guards..? Whaaatt….!!??.
Think about it…. You're a good rider trying to get maximum days in, pushing hard, elevating your game. Odds are, gravity is going to win occasionally and the ground, or maybe a cold steel rail with a bad attitude will abruptly rise up to violently greet you.
I'm not advocating everyone ride around all trussed up like the Stay-Puft Marshmallow Man. Base your usage of protective gear on riding style and ability. Beginners really need wrist, knee and butt protection Experienced riders enjoying soft pow on mellow terrain are pretty low risk. Venturing into the woods ratchets up that risk factor considerably with a corresponding need for body, head and eye protection in case of an unintended encounter with Jack Pine. If you're building two story cheese wedges trying to out huck Mads or Travis, a full padded suit might be a good idea.
Somewhere in between is the pipe/park junkie who are prone to separated shoulders, fractured collarbones and other upper extremity trauma. Several manufacturers (Ok, a quick note here. I don't want to call out any specific manufacturers cuz I can't name them all, they're all good and I don't want to cause bad feelings if I neglect someone. Hit up Mr. Google and find the shit that works for you) Upper body protective suits are pretty low profile and easy to move in these days and might prevent internal injuries like my co-worker who had to have his spleen removed a couple years ago after coming up short on a big gap.
Shinners on rails really suck. They tend to be more nuisance injuries but hurt like hell and take a long time to heal. Do you want to live through weeks of stitches in your shin or bruised ribs because you were a little rusty on a rail you had dialed last spring..? Good gear is available and way cheaper than the Dr.'s office
And let's not forget unscheduled dentistry… Toothless might be cool for old school hockey players and Scotty Whitlake but let me be the first to tell you it's no fun going to your dentist wwith your busted grille in your hands and periodontal surgery isn't worth the laughing gas. My mom wasn't very happy either. Comfortable mouth guards are widely available and are so low profile it's hard to tell you're using one. Guard your grille…
Wondering why footbeds made it into my list…? Well, your feet are the basic interface between the rest of you and your board. They absorb tremendous punishment while snowboarding and are still expected to respond instantly to subtle feedback transmitted thru the board/binding/boot. A good footbed supports the foot, reducing stress on the complex structure and can prevent crippling heel bone bruises or fractures even. Not much blood gets to the bones of the ankle or heel so they take forever to heal. You might even consider running commercially available jell heel cushions if you're working urban rails most of the time. Repetitive hard landings on flat concrete add up quick.
The name of the game is protect your vital interests. I don't know about you but I'm vitally interested in riding hard, all the time, pain free.