Anatomic considerations in dacryocystorhinostomy: The middle turbinate

BACKGROUND: A successful dacryocystorhinostomy creates a fistula between the lacrimal sac and the nasal cavity. Failure rates range from 5-10%, and are commonly related to scar formation with adjacent structures including the middle turbinate. The normal relationship of the middle turbinate to the nasolacrimal fossa is unknown. This study evaluates that relationship in a normal population. METHODS: Computed tomography (CT) data from 50 normal patients was obtained. Two independent reviewers measured the overlap of the lacrimal fossa with the ipsilateral middle turbinate. RESULT S: Eighty-two percent of patients (41 out of 50) had overlap of the lacrimal fossa with the middle turbinate. Overlap was 2.2±2.9 mm (right) and 2.0±2.7 mm (left). Concordance between the two independent readers was very high (x²>0.99). CONCLUSIONS: One of the most common reasons for DCR failure is postoperative scarring. This study finds that 82 percent of normal CT scans have overlap between the lacrimal fossa and middle turbinate. Surgeons should be careful to avoid abrasion of opposing mucosal surfaces that may lead to scaring and persistent epiphora. If middle turbinate overlap is noted intraoperatively, consideration should be given to trimming of overlapping turbinate mucosa.