Why does a LBL incision dissect the butt crack or sits above it?

The position of the incision is key to prevent the elongation. If it is located above the cleft or over the lower back it definitely will lengthen it  
As expert on the After weight loss surgery and a passionate of The lower body lift procedure I always try to prevent that. 
Be encouraged!!Dr  Cardenas 

Thank you for your question: "Why does an LBL incision dissect the butt crack or sit above it?" During a 360 circumferential lower body lift, an incision is made on the abdomen, travels over the hips, and meets at the top of the buttock. The incision would not complete and would stop at the center of the buttock. This would result in dog ears or collections of excess skin and fat. This would not be optimal; one option would be to bring the incision higher than the buttock crack. However, if this is done when you are wearing pants, the incision would be visible from behind. Another option would be to bring the incision low on the buttock, but the incision would meet in the buttock crack and would not heal well and lead to a deformed buttock. This explains the positioning of the lower body lift incision. The buttock lift becomes "extended" because of the skin folds. If you look carefully at body lift pictures, it is not that the buttock crack is brought above the scar; the buttock crack is brought to the scar. In the after photos, you see folds of skin above the buttock crack. This is not the native or original buttock crack creases of skin above the buttock crack. This explains the buttock crack above the body lift scar. Thank you for your question regarding buttock crack elongation and why the incision from a body lift meets at the top of the buttock crack.

I specialize in reconstructive plastic surgery after weight loss. If you have any more questions regarding the lower body lift, 360 circumferential lower body lift, belt lipectomy, belt abdominoplasty, or belt dermolipectomy please contact my office. Since the body lift is a big procedure, please seek an experienced, board certified plastic surgeon with significant experience performing the lower body lift. Do your research. Make sure they have performed at least 100 circumferential lower body lift surgeries and have the before and after pictures to prove it. Carefully examine their before and after pictures and check their reviews on RealSelf.  If you cannot find an experienced, lower body lift surgeon in your neighborhood, consider traveling out of state if you must. Sincerely, Dr. Katzen. (“Verified” Plastic Surgeon, President of the American Society of Bariatric Plastic Surgeons, certified by the American Board of Plastic Surgery, Fellow of the International Society of Aesthetic Plastic Surgery, American College of Surgery, and International College of Surgery and ​member of the American Society of Plastic Surgery, American Academy of Cosmetic Surgery and RealSelf Hall of Fame.)

Thank you for your question. The incision is placed above the butt crack along the lower back to maximize the lift. The skin that's above the butt crack is where you will get a better pulling of the skin and if needed the butt crack can be extended. For the best results I would recommend that you have a consult with a Board-certified plastic surgeon.