Microsurgical Treatment of Posterior Cerebral Circulation Aneurysms Via Keyhole Approaches

Objective

To explore the techniques of microsurgical treatment for posterior cerebral circulation aneurysms via keyhole approaches and assess its feasibility.

Methods

A total of 27 patients with 28 posterior cerebral circulation aneurysms were treated surgically by keyhole approaches; 24 patients presented with subarachnoid hemorrhage and 3 with headache. Of these 27 patients, 15 patients were treated via the supraorbital keyhole approach, 6 via the retrosigmoid keyhole approach, 3 via the subtemporal keyhole approach, 2 via median suboccipital approach, and 1 via the pterional keyhole approach.

Results

Of the 28 posterior cerebral circulation aneurysms, 24 aneurysms were clipped and 4 trapped; 23 aneurysms clipped completely, and 1 had residual aneurysm. Glasgow Outcome Scores at discharge revealed 25 patients had a good recovery; 1 patient was slightly disabled, and 1 patient was severely disabled. Of 15 patients treated via the supraorbital keyhole approach, to make a wider operative space, drilling of anterior clinoid process (2 patients) and posterior clinoid process (3 patients) was performed; posterior communicating artery was cut off (1 patient). For 3 patients with multiple aneurysms, complete occlusion was achieved via the same approach at one-stage.

Conclusions

Individualized keyhole approaches for posterior cerebral circulation artery aneurysms are safe and effective. The anterior clinoid process or posterior clinoid process could be drilled to offer a wide operative space for clipping. The use of multiple working windows is very helpful for controlling the parent artery and clipping the aneurysm.

Introduction

The management of posterior circulation aneurysm remains challenging to neurosurgeons because of its deep location, difficult exposure, numerous surrounding cranial nerves and perforators, narrowness of surgical field, and limited space to operate. Great advances have been gained in surgery for posterior circulation aneurysms as the result of the skull base approach, which could reduce brain retraction, shorten distance, and enlarge the working space. The keyhole approach is one kind of skull base approach that avoids unnecessary destruction and exposure of the brain and preserves the required manipulating space, or the “key hole” part. Because of its narrow space, the internal structure feature is an unchangeable aspect regardless of the size of the bone window outside. The bone window for posterior circulation aneurysms could reach the size of the keyhole space via effective preoperative approach design.

Reisch and Perneczky (12) first reported the supraorbital keyhole approach for posterior circulation aneurysm clipping in 2005. We also demonstrated its feasibility through related anatomic studies (10). The classic example of a keyhole approach is supraorbital, which is used widely in sellar tumor resection and anterior circulation aneurysm clipping 1, 3, 6, 8, 11, 13. At that time, we fully opened cisterns to clean off subarachnoid hematocele and to observe posterior circulation by opening the interpeduncular cistern. Here, we report the results of our use of the keyhole approach in 27 patients with posterior circulation aneurysms after sufficient preoperative preparation.