Transorbital Keyhole Approach to Anterior Communicating Artery Aneurysms

Abstract

In Reply: We appreciate the comments of Drs. Grand, Landi, and Daré, who report that they have used a supraorbital minicraniotomy alone or in combination with orbitotomy for a variety of intracranial lesions. In a recent article, Shanno et al. (1) reported that they used a transorbital roof craniotomy in 72 patients, primarily for tumor resection. Obviously, this type of approach is increasingly used for various indications. However, we want to emphasize that, in our opinion, incorporating the orbital roof is a crucial point, particularly in surgery for anterior communicating artery (AcomA) aneurysms. In contrast to the pure supraorbital craniotomy, removal of the orbital roof allows a very low basal approach with minimal brain retraction and entirely extracerebral dissection of the AComA complex, in the majority of cases. The extent or need for a gyrus rectus resection should be reduced as far as possible, especially in view of the minimal invasiveness of endovascular procedures and possible cognitive deficits. We agree with Grand et al. that it is always difficult to prove the benefit of a new procedure and to establish its advantages over the old, more standard procedure. We certainly do not recommend this approach when a neurosurgeon deals with his first AComA aneurysm. However, once the neurosurgeon is familiar with the surgical anatomy of the AComA complex and its variants, the transorbital approach provides approximately the same wide exposure and instrumentation space with less brain retraction or resection than the standard pterional approach. In this respect, the term “keyhole” might be misleading. With growing experience, the time required for this approach at our institution is even less than for the standard pterional approach, with drilling off the sphenoid ridge and flattening of the roof of the orbit. The long-term cosmetic results seem superior. We prefer an incision line behind the hairline, as for the pterional approach, instead of an eyebrow incision because an incision line remains even with the most meticulous closure technique. To date, we have operated on more than 60 AComA aneurysms using this approach exclusively (2). We have not observed any cerebrospinal fluid leakage, which has been said to be more common with the use of the transorbital than the pterional approach (1). This result might be related to the use of a hairline incision instead of an eyebrow incision. The hairline incision facilitates harvesting a piece of temporal muscle or fascia for dural repair or fashioning a pericranial flap when the frontal sinus is opened. Encouraged by recent reports, we are looking forward to extending the use of the transorbital approach to other indications. Robert Schmid-Elsaesser Hans-Jakob Steiger