External Nasal Valve Efficacy Index: a simple test to evaluate the external nasal valve.

Many methods and techniques have been proposed for the assessment of the nasal valve, most requiring special equipment. Furthermore the main focus has been on the internal valve, while the role of the external nasal valve (ENV) has usually been underestimated. An index to assess ENV is presented herein. Two photographs of the basal view of the nose are taken, one in the resting position and the other after deep inspiration. These two life-size views are used to calculate the External Nasal Valve Efficacy Index (ENVE Index). Using simple software, the surface area of the nostril in the resting view (A) and breathing view (B) is measured. The ENVE Index is calculated by dividing the deep inspiration surface area by the resting surface area (B/A). The clinical indications for the use of the ENVE Index include rhinoplasty treatment planning, postoperative evaluation to assess the effects of surgery with regard to improvement or deterioration of the airway, and orthognathic surgery and the planning of appropriate postoperative care (such as elastic or intermaxillary fixation) according to the airway patency. The ENVE Index is a relatively simple, reproducible, and documentable test. This index can help the surgeon to make better decisions during treatment planning and postoperative care.