Yes, you can.
But not as a person with an unfused spine would. Practicing one-on-one or in a small specialized group with a qualified teacher (500 hours of training+) or yoga therapist (800hrs+) is your safest bet. It is important to note that all yoga certifications are NOT the same. Many yoga studios have mainly 200hr trained teachers and gyms often have teachers that have only attended a weekend training. A good friend of mine took a 200 hour training that never taught them how to teach the physical yoga poses!
General group classes often are taught by new teachers (or those having no experience in scoliosis and fused spines) and those classes will include repetitions of the yoga pose “DON’TS” listed below:
Twists: after a fusion your spine no longer has the ability to fully rotate.
Forward bends & Back bends: after spinal fusion surgery you no longer have a natural curve that bends. Areas of the spine that aren’t fused will pick up the slack and end up overused and subject to injury.
Full head/neck rotations: this movement isn’t safe for anyone, especially if we’ve had any kind of fusion or surgery into the cervical spine. If a teacher cues this movement, that’s your cue to find another teacher.
NEVER FEAR! Yoga can still be practiced happily and with the many benefits it has to offer. Yes, even leaving out those poses mentioned above. 😉