Optic Nerve Sheath Fenestration: Current Preferences in Surgical Approach and Biopsy

Purpose: Optic nerve sheath fenestration (ONSF) has evolved since its inception in 1872. Surgical approaches include a lateral orbitotomy, a medial orbitotomy, or a superomedial lid crease. The actual fenestration can be done with slits or a window excision with biopsy. Each variation has its advantages and disadvantages. We describe the current preferences in surgical approach and biopsy for ONSF and examine the value of biopsy in patients who have undergone ONSF. Design: Eight-question survey and retrospective, noncomparative case review. Subjects: All American Society of Ophthalmic Plastic and Reconstructive Surgeons (ASOPRS) members are invited to participate in a survey and ONSFs from 1998 to 2013 at the University of Iowa Hospital and Clinics. Methods: Data from the survey was analyzed and patient records were reviewed. Main outcome measures: Preferred surgical approach, type of fenestration, and biopsy results. Results: Sixty-four percent of responding ASOPRS members (150/236) have not performed an ONSF in the last year. One third of that group has performed an ONSF in the last 5 years. Fifty-nine percent perform a medial; 10%, a lateral and 31%, a superomedial approach. Seventy-three percent perform a window fenestration, and about half of those surgeons send the specimen for pathologic evaluation. Anecdotally, some biopsies from surgeons who were surveyed have revealed new diagnoses. In a chart review of 90 cases of ONSF, no biopsy gave an unexpected result. Conclusion: The medial approach for ONSF is most common in our respondents; however, the superomedial lid crease incision is gaining popularity for its efficiency and elegance. Three quarters of surgeons remove a window and a quarter fenestrate with slits. Optic nerve sheath biopsy has limited diagnostic value. In the absence of any evidence to suggest a diagnosis other than idiopathic intracranial hypertension, the usefulness of biopsy during fenestration is low.