title: Etiology, definition, and classification of gluteal ptosis.
abstract: BACKGROUND
  Despite the growing interest in aesthetic surgery of the buttocks and posterior body contouring, there is no clear definition of gluteal ptosis nor any classification enabling standardized diagnoses and treatments of the problem. The author proposes a classification to differentiate between pseudo-ptosis, PRE-ptosis, and true ptosis. The classification includes five degrees of severity and two factors (the length of the lower gluteal crease and the measurement, in centimeters, of posterior gluteal tissue exceeding the crease at a sagittal line that passes through the middle of the thigh, seen from behind, which the author proposes to call the "M" line). The article exposes the anatomy involved in ptosis and presents a theory about the mechanism through which gluteal ptosis is formed.
  
  
  METHODS
  During a 1-year period, 87 patients, eligible for different types of body aesthetic surgery, were assessed according to the proposed classification. Their ages ranged from 16 to 64 years, and their weight ranged from 43 to 82 kg. Body mass index was used to classify overweight patients. Weight loss was considered in 10% increments.
  
  
  RESULTS
  The authors were able to classify all the patients according to the proposed classification. Weight, age, and weight loss were directly related to the severity of the ptosis.
  
  
  CONCLUSIONS
  The proposed classification is easy to apply and has the ability to standardize diagnoses and treatments for gluteal ptosis. This study also shows that weight gain, aging, and weight loss are etiologic agents of ptosis.
authors.affiliation: Clinica Raul Gonzalez, Plastic Surgery, Ribeirao Preto, Sao Paulo, Brazil. rg@raulgonzalez.com.br
authors.forename: Raul
authors.initials: R
authors.lastname: Gonzalez
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D002081:Buttocks / Q000033:anatomy & histology* / Q000473:pathology* / Q000601:surgery; D007839:Functional Laterality; D006801:Humans; D008875:Middle Aged; D019651:Plastic Surgery Procedures / Q000379:methods*; D015431:Weight Loss