The ruptured anterior communicating aneurysm poses challenges due to variations in anatomy and due to depth and dominance of the anterior cerebral artery, approaches and surgical strategies may also vary. Many questions run through a surgeon’s mind before surgery on these aneurysms. What are the specific criteria for choosing between a pterional craniotomy and a transbasal anterior interhemispheric approach for Acom A aneurysms? What are the potential complications associated with temporary clipping and how can they be mitigated? How does the presence of atheromatous vessels impact the choice of clipping technique during surgery? While a digital subtraction angiogram with three-dimensional (3D) reconstruction can provide the details of the aneurysm’s projection and dominance, a 3D computed tomography (CT) angiogram, particularly with the floor of the anterior cranial fossa, can provide a more realistic forecast that can be used as a simulation for preoperative planning.1 The surgeon should attempt to view the images and reconstruct the 3D rendering volume images himself in the CT console, in a manner that corresponds to the patient’s position, thereby enabling real-time intraoperative aneurysm projection and visualization of the relationship to distal anterior cerebral arteries. While a pterional craniotomy (through dominant A1) is the main surgical workhorse, a few cases of giant Acom A aneurysms may warrant a trans basal anterior interhemispheric approach.2 Minimally invasive techniques such as supraorbital keyhole craniotomy and purely endoscopic approaches are being done in select cases with the least morbidity.3,4 To reach the aneurysm depth, a relaxed brain is of paramount importance; there are many ways to achieve this, including preoperative lumbar cerebro spinal fluid (CSF) drainage, CSF release from the carotico-optic cisterns, and external ventricular drainage if hydrocephalus is present. The surgeon should be aware of Paine’s point to tap the frontal horn in case of an unexpected brain bulge after durotomy.5 The key steps involved in reaching the aneurysm are to identify and trace the ipsilateral A1 and follow it to the interhemispheric cistern, where the A1 turns vertically to form the A2, and the aneurysm would be mostly projected in this junction. A gyrus rectus resection becomes mandatory in most cases for exploring the detailed anatomy in that location, especially to identify the contralateral A2. Identifying both A1 and A2, the frontopolar branches, and Huebner’s artery is essential for safe clip deployment. In rare instances, one can sacrifice the frontopolar branch if deemed necessary to prevent aneurysm rupture, especially when the branch loop is adherent to the fundus or neck of the aneurysm. Often, the subfrontal approach is the primary corridor rather than the trans-sylvian corridor. The only word of caution when retracting the frontal lobe base is that, in cases of anterior-inferior aneurysm projection, if the fundus becomes adherent to the chiasm surface, retraction can lead to premature rupture. Even if that happens, the surgeon should remain cool, get the suction to the bleeding point to avoid spillage and to clear the field (the role of the assistant surgeon is very crucial at this juncture) and at the same time, a tentative clipping has to be done to prevent further bleed and once that is done, further dissection and permanent clipping can be done after proper exposure.6 While most aneurysmal projections can be managed with ease, the posterior projection poses unique challenges, as hypothalamic perforators may be close to the neck and could be occluded by apermanent clip if not recognised. Hence, after clipping, a thorough inspection should be conducted, especially using a sodium fluorescence filter, to ensure that the clip blades do not contain any perforator. Another common mistake is the tip of the clip catching the origin of the contralateral A2. Releasing the clip blade and partially withdrawing it can help manage this. In aneurysms with anterolateral projection, especially superiorly, the distal neck may be missed, resulting in residual neck and potentially leading to rebleeding in the postoperative period. Even ICG angiography could miss this, and when in doubt, puncturing the fundus post clip application and the collapse of the sac may be the best way to ensure complete aneurysmal obliteration. The other end of the spectrum is the overzealous application of the clip too close to the neck, especially in elderly patients with atheromatous vessels, which can lead to narrowing or occlusion of the ipsilateral A2 and/or the contralateral A2. In such instances of atheromatous vessels, placing the permanent clip just distal to the identified neck can prevent in-flow occlusion of the distal vessels.7 The other topic of discussion is the use of temporary clipping: Whether it is required and what the ideal duration is, both of which remain debatable. However, the consensus is to use temporary clipping, preferably on both A1, for a period not exceeding 10 min, to ensure safe dissection of the neck and placement of the permanent clip. Some surgeons do not want to use the temporary clip for fear of causing ischemia in the already compromised circulation, and it is completely their discretion. In general, temporary clipping reduces the incidence of intraoperative aneurysmal rupture.8 After clipping the aneurysm, it is essential to irrigate all cisterns with warm saline or Ringer’s lactate to remove clots and open the lamina terminalis to reduce the incidence of delayed hydrocephalus. This also helps in washing the subarachnoid cisterns.9 Postoperative management is very crucial for a good outcome. One should be very watchful of the fluid and electrolyte disturbances, which are very common in the vasospasm period. Adequate hydration, maintenance of blood pressure, and avoidance of hyperthermia are imperative. Postoperative CT angiography can be performed for immediate assessment, followed by transcranial Doppler, to optimize the management of vasospasm.10 To summarize, surgery for Acom aneurysms requires strategic planning and execution to ensure proper clip placement and achieve favorable outcomes. Despite advances in endovascular management, surgery remains indicated for these aneurysms in a significant subset of patients. Contribution details Dr. R. Raghavendran contributed toward concept, design, definition of intellectual content, literature search, clinical studies, manuscript preparation, manuscript editing, and manuscript review.
R Raghavendran (Thu,) studied this question.