The anterior skull base nasal inventory (ASK nasal inventory): a clinical tool for evaluating rhinological outcomes after endonasal surgery for pituitary and cranial base lesions

The goal of this project was to develop a prospectively-validated, site-specific patient quality of life survey for assessing nasal outcomes following endonasal pituitary and skull base surgery. (ClinicalTrials.gov #NCT01322945) An 9-item patient survey (the ASK Nasal Inventory) focusing on the most common postoperative complaints, such as crusting, sinusitis, pain, and ease of breathing, was developed by the anterior skull base team at the Barrow Neurological Institute. Content was validated in structured patient interviews and by four subject matter experts. This survey was self-administered before and 3 months after surgery to 94 patients (52 endonasal surgery and 42 controls) between October 2010 and June 2011. Standard methods for psychometric evaluation were applied. Cronbach's alpha was 0.83 indicating good internal consistency. Test-retest reliability was excellent in both groups (r = 0.87 and 0.95; P < 0.001). Discriminant validity was determined by comparing mean scores at 3 months in the endonasal and control groups and the difference was significant (13.5 vs. 17.2, P = 0.001). Standardized response mean was 0.17 suggesting that the scale was sensitive to clinical change. Concurrent validity was determined by mean ASK Nasal score for each level of self-reported overall functioning at 3 months (P = 0.001). Preliminary psychometric evaluation of the performance of the ASK Nasal Inventory suggests that it meets criteria as a clinical and research instrument in endonasal surgery. This study also suggests modifications to the instrument, which will serve as key quality of life endpoint in an ongoing multicenter nasal outcomes study.