Posterior communicating artery aneurysms causing facial pain: A comprehensive review

- PComAAs causing trigeminal neuralgia are uncommon lesions with particular features.
- TN-PComAAs have large size and predominantly project posterior-medial-inferiorly.
- PComAAs cause atypical TN with predominant V1 and V2 distributions involvement.
- TN-PComAAs have a high tendency to cause third nerve palsy due to their large size.
- Surgical TN-PComAAs clipping provides good neurological outcome and pain relief.

Posterior communicating aneurysms are commonly associated with oculomotor nerve palsy. However, trigeminal nerve involvement among these aneurysms is a rare event with no previous analysis. In order to describe the main features of posterior communicating aneurysms causing trigeminal neuralgia (TGN-PComAAs) eight cases (six from the literature plus two more illustrative cases) were included in the present series. All cases were thoroughly studied in order to collect their epidemiological, radiological, clinical, therapeutic, pathogenic, and outcome data. The mean age at diagnosis was 57 years. Gender distribution showed a female predominance (M-to-F ratio 3:5), while side distribution showed a slight left dominance (62%). The aneurysms mean size was 24.7 mm (range: 7-40 mm). In 7 cases (87.5%) the PComAA was reported to project posteriorly, associated with cavernous sinus extension/compression in two of them and posterior fossa extension in three. No case presented with hemorrhage. Facial pain was the clinical onset in all eight cases, which was reported as an atypical TGN (continuous with exacerbating fits) in 87.5%. Trigger points were absent in all cases but one (87.5%). The most frequent anatomical distribution of the pain was V2 alone (n = 3), followed by V1-2 (n = 2) and V1-2-3 (n = 2). Three different mechanisms for trigeminal neuralgia were observed, namely, cavernous sinus compression (n = 4), direct trigeminal root compression (n = 3), and oculomotor nerve compression (n = 1). Three different treatment options were performed: surgery (n = 6), trigeminal thermo-rhizotomy (n = 1) and medical management (n = 1). According to the Barrow Neurological Institute (BNI) score the pain control after main treatment was I (no pain with no medication) in 7 cases (87.5%). The average modified Rankin scale (mRS) score was 1. In sum, TGN-PComAAs are infrequent lesions characterized by large size and posterior-medial-inferior projection. They mainly cause atypical TGN, most commonly involving the first and second trigeminal distributions (V1-V2). Surgical aneurysmal clipping has been the most frequent treatment option for these aneurysms, providing good neurological results in a vast majority and complete trigeminal pain relief in all cases.