CASE REPORT J Neurosurg 128:1808–1812, 2018 A s many as 30%–37% of all cerebral aneurysms oc- cur within the region of the anterior communicat- ing artery (ACoA). 1,4,6 Due to their proximity to the optic apparatus, ACoA aneurysms may present with symp- toms of compressive optic neuropathy (CON). 3,9 Multiple reports have described exacerbation of CON secondary to aneurysm expansion following coil embolization. 5,7,8,10 Mi- crosurgical clipping of ACoA aneurysms has been reported to result in favorable optic nerve function when compres- sion by the aneurysm is suspected, as the aneurysm can be decompressed after clipping. 2 However, clip-related CON after microsurgical treatment has not been well described. We report 3 cases in which an afferent pupillary defect (APD) was detected following clip ligation of ACoA an- eurysms, in which reexploration with repositioning of the clip led to resolution of visual symptoms. Case Reports Case 1 A 61-year-old woman presented to the emergency de- partment with severe headache and lethargy. At presenta- tion she demonstrated a Hunt and Hess Grade V and World Federation of Neurosurgical Societies (WFNS) Grade V subarachnoid hemorrhage (SAH). CT demonstrated modi- fed Fisher Grade 4 SAH (Fig. 1). A diagnostic cerebral angiogram revealed an ACoA aneurysm. We performed a right-sided frontotemporal craniotomy for microsurgical clip ligation of the aneurysm., applying a Mizuho (Mizuho Medical Co.) MRI-compatible bayonet- ed clip applied to the aneurysm neck. Twenty-four hours following the procedure, there was concern for an APD on the right side, which was confrmed though evaluation by ABBREVIATIONS ACoA = anterior communicating artery; APD = afferent pupillary defect; CON = compressive optic neuropathy; SAH = subarachnoid hemorrhage; WFNS = World Federation of Neurosurgical Societies. SUBMITTED October 19, 2016. ACCEPTED February 9, 2017. INCLUDE WHEN CITING Published online August 25, 2017; DOI: 10.3171/2017.2.JNS162654. Optic neuropathy after anterior communicating artery aneurysm clipping: 3 cases and techniques to address a correctable pitfall Joseph R. Linzey, BS, 1 Kevin S. Chen, MD, 2 Luis Savastano, MD, 2 B. Gregory Thompson, MD, 2 and Aditya S. Pandey, MD 2 1 University of Michigan Medical School, and 2 Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan Brain shifts following microsurgical clip ligation of anterior communicating artery (ACoA) aneurysms can lead to me- chanical compression of the optic nerve by the clip. Recognition of this condition and early repositioning of clips can lead to reversal of vision loss. The authors identifed 3 patients with an afferent pupillary defect following microsurgical clipping of ACoA aneurysms. Different treatment options were used for each patient. All patients underwent reexploration, and the aneurysm clips were repositioned to prevent clip-related compression of the optic nerve. Near-complete restoration of vision was achieved at the last clinic follow-up visit in all 3 patients. Clip ligation of ACoA aneurysms has the potential to cause clip-related compression of the optic nerve. Postoperative visual examination is of utmost importance, and if any changes are discovered, reexploration should be considered as repositioning of the clips may lead to resolution of visual deterioration. https://thejns.org/doi/abs/10.3171/2017.2.JNS162654 KEY WORDS afferent pupillary defect; anterior communicating artery aneurysm; intracranial aneurysm; optic nerve injuries; surgical clips; vascular disorders J Neurosurg Volume 128 • June 2018 1808 ©AANS 2018, except where prohibited by US copyright law Unauthenticated | Downloaded 09/13/21 11:21 AM UTC