Can a doctor accidentally stab you in your back (spine) or stomach while doing lipo? Does this cannula scrape the insides?

Liposuction is a very safe procedure in the hands of an experienced board-certified plastic surgeon. In an inexperienced non-plastic surgeon it can be fraught with disaster. 

Whenever a surgical procedure is undertaken certain complications fall within the realm of possibilities. However, perforation of organs or major vital structures is extremely rare. It's of the most importance that you research carefully the surgeon you select. When a properly trained surgeon is selected, the probabilities decrease exponentially.Always seek out the opinion of a surgeon certified by the American Board of Plastic Surgery with years of experience in liposuction . Furthermore request to see before and after photos of previous patients by that doctor....not a clinic or surgery center. Do your homework......research and verify the doctor's credentials. Have they had problems with the Board of Medicine, disciplinary or otherwise. Any law suits? How about the center, clinic or facility? Are they accredited by a national organization or do they just have State approval. Understand that at the current time, there are three nationally recognized organizations responsible for the highest levels of patient safety, AAAASF, AAACH and JCHO. You owe it to yourself to position yourself for the best possible results but under the most stringent safety regulations, If you have kids, even more so.How about anesthesia? Will you have a medical doctor certified by the American Board of Anesthesiology or a certified nurse anesthetist (CRNA)? Understand that there is no substitute for research. Cosmetic surgery, no matter how simple it may be to the patients, are invasive procedures and as such carry certain risks and complications.

Practically anything's possible during operation but with a properly trained board-certified plastic surgeon damage to anything but the subcutaneous fat with liposuction should be almost unheard of.

Liposuction technique is very safe when performed by a trained professional, i.e., board certified plastic surgeon.  Nonetheless there have been rare cases of complications from cannula perforations etc.  Ensure your plastic surgeon is experienced in the procedure you are interested in. 

It is always best to seek an experienced Board Certified Plastic Surgeon for in person consultation to address all of your questions.

If you are so unsure about doing liposuction with fat transfer than better to see a few boarded PSs in South Florida to fully explain the operation to you in detail. Over the internet we can not alleviate your paranoia. 

You are right to be concerned.  Much more important than which techniques are employed is the hand that wields the instruments.  Many doctors hold themselves out to be "cosmetic surgeons" but are not certified by the American Board of Plastic Surgery.  Be sure to check your surgeon's credentials carefully.  "Certification" by anything other than "The American Board of Plastic Surgery" (ABPS) is meaningless as regards training and expertise.Anyone can buy liposuction equipment; anyone can take a weekend course; anyone can become a member of any number of non-ACGME accredited "boards."  Does your surgeon have privileges at a hospital to perform that which is offered in an office or surgicenter? Did you surgeon complete a full residency/fellowship and obtain Board Certification?People die from liposuction from embolisms and from ruptured organs.  Be sure your doctor is properly trained and certified.  Beware of the practitioner who offers you other than ABPS credentials.

Don't be frightened. It is not likely a perforation of the spine or body cavity would happen with lipo. BUT, to be most cautious make sure you check the credentials of your plastic surgeon. Board Certified by the American Board of Plastic Surgery.