Abnormal variations in the facial soft tissues of adult uremic patients on chronic dialysis

Renal osteodystrophy is a common complication of uremic patients, mainly when they are in long-term regular dialysis treatment. The craniofacial skeleton is one of the peculiar targets of renal osteodystrophy, the more dramatic pattern of which is a form of leontiasis. To assess facial deformities in uremic conditions and to understand the possible relation with hyperparathyroidism, the three-dimensional coordinates of 50 soft tissue facial landmarks were obtained by an electromagnetic digitizer in 10 male and 10 female patients (aged 53-81 years) with chronic renal insufficiency and regular dialysis treatment. Similar three-dimensional coordinates were also collected for 34 healthy individuals of the same age, ethnicity, and sex. From the landmarks, facial distances, angles, and volumes were calculated according to a geometrical model of the face. Data were compared with those collected in the normal subjects by computing z-scores. Facial volumes of the chronic renal insufficiency patients were significantly larger than those of the control subjects. The increment was particularly evident in the facial middle third (maxilla), leading to a significant inversion of the mandibular-to-maxillary ratio. The lips tended to be more prominent (reduced interlabial angle). Some of these facial modifications (facial and nose height, maxillary dimensions, mandibular shape) were significantly related to the clinical characteristics of the patients (duration of renal insufficiency, duration of dialysis, parathormone (PTH) plasma levels). In regular dialysis treatment, some of the facial modifications are related to hyperparathyroidism, which supports the need for a strict metabolic control also in the early phase of uremia.