Patient-reported quality-of-life (QOL) end points are becoming increasingly important health care metrics. To date, no nasal morbidity instrument specifically designed for patients undergoing endonasal skull base surgery has been developed. In this study, the authors describe the development and validation of a site-specific nasal morbidity instrument to assess patient-reported rhinological outcomes following endonasal skull base surgery.
Eligible patients included those with planned endonasal transsphenoidal surgery for sellar pathology identified in outpatient neurosurgical clinics of 3 skull base centers from October 2011 to July 2012. An initial 23-question pool was developed by subject matter experts, review of the literature, and from the results of a previous validation study to assess for common rhinological complaints. Symptoms were ranked by patients from “No Problem” to “Severe Problem” on a 6-point Likert scale. Exploratory factor analysis, change scores, and importance rank were calculated to define the final instrument consisting of 12 items (The Anterior Skull Base Nasal Inventory-12, or ASK Nasal-12). Psychometric validation of the final instrument was performed using standard statistical techniques.
One hundred four patients enrolled in the study. All patients completed the preoperative survey and 100 patients (96%) completed the survey 2–4 weeks after surgery. Internal consistency of the final instrument was 0.88. Concurrent validity measures demonstrated a strong correlation between overall nasal functioning and total scores (p < 0.001). Test-retest reliability measures demonstrated a significant intraclass correlation between responses (p < 0.001). Effect size as calculated by standardized response mean suggested a large effect (0.84). Discriminant validity calculations demonstrated that the instrument was able to discriminate between preoperative and postoperative patients (p < 0.001).
This prospective study demonstrates that the ASK Nasal-12 is a validated, site-specific, unidimensional rhinological outcomes tool sensitive to clinical change. It can be used in conjunction with multidimensional QOL instruments to assess patient-reported nasal perceptions in endonasal skull base surgery. This instrument is being used as a primary outcome measure in an ongoing multicenter nasal morbidity study. Clinical trial registration no.: NCT01504399 (ClinicalTrials.gov).