A variety of options are currently available for treating excess trunk skin following massive weight loss. The specific procedure chosen is dependent upon the patient's anatomic findings and aesthetic goals.Unfortunately, there continues to be some confusion regarding the terminology utilized to describe these procedures. Abdominoplasty describes procedures that are utilized to remove excess abdominal skin while simultaneously tightening the abdominal muscles. When the abdominal incision is extended into the flank region, an extended abdominoplasty is performed. When the procedure is extended circumferentially around to the back, a lower body lift is performed. Excision of excess back skin results in the buttock being lifted in an upward directionAlthough your pictures are helpful, they don't demonstrate the degree of buttock sag. For this reason, it's difficult to make a recommendation without additional pictures or a physical examination. Based on your history and a single picture, I believe you would benefit from either an extended abdominoplasty augmented with liposuction of the hips or a lower body lift.If you're considering this type of procedure, it's appropriate to consult a board certified plastic surgeon with experience in this area. This surgeon should be able to formulate a treatment plan that addresses your anatomic findings and achieves your aesthetic goals.