The "Keystone Angle": Geometry in Preservation Rhinoplasty.

Rhinoplasty outcome may depend on different factors and bony dorsum shape has proven to significantly influence the lateral view result. The "Keystone angle" corresponds to the osseocartilaginous angle formed between bony and cartilaginous dorsum. Usually, the "V" shaped bony dorsum is characterized by a more acute "Keystone angle" compared to the "S" shaped bony dorsum. To achieve the ideal dorsum flatness, corresponding to a "Keystone angle" of 180°, different techniques may be used. Bearing these concepts in mind we suggest that preoperative assessment of the "Keystone angle" can guide the choice of the most appropriate technique for each patient. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .