Circumferential Distal Dural Ring Opening Through a Natural Microsurgical Dissection Corridor: A Plane-Oriented Strategy for Paraclinoid Aneurysm Surgery.

BACKGROUND

Safe circumferential distal dural ring (DDR) opening remains one of the most technically demanding steps in microsurgical clipping of paraclinoid aneurysms. This study aimed to characterize the anatomical conditions associated with successful circumferential distal dural ring opening and to present a plane-oriented microsurgical strategy for paraclinoid aneurysm surgery.

METHODS

We retrospectively reviewed 51 consecutive patients who underwent microsurgical clipping for paraclinoid aneurysms requiring distal dural ring (DDR) opening. DDR opening was defined as any incision of the distal dural ring, whereas circumferential DDR opening was defined as near-circumferential opening around the internal carotid artery to permit dissection along its medial aspect. Patients were classified into the circumferential DDR opening group and the non-circumferential DDR opening group. Factors associated with circumferential DDR opening were analyzed using univariate analysis followed by multivariable logistic regression. Two representative surgical cases were included to illustrate the anatomical concept and microsurgical technique.

RESULTS

Among 51 patients, circumferential DDR opening was achieved in 22 (43%). Univariate analysis identified carotid cave aneurysm (Barami type IIIb) as significantly associated with circumferential DDR opening. On multivariable logistic regression analysis, only Barami type IIIb remained independently associated with successful circumferential DDR opening.

CONCLUSIONS

Successful circumferential distal dural ring (DDR) opening is best understood not as the extent of dural incision itself, but as the natural consequence of correctly identifying and faithfully following the natural microsurgical dissection corridor. This anatomical principle may facilitate safer and more reproducible microsurgical treatment of paraclinoid aneurysms.