Preoperative 3D slicer reconstruction and the prognostic value of dynamic intraoperative lateral spread response assessment in vertebrobasilar dolichoectasia-associated hemifacial spasm.

OBJECTIVE

To evaluate the value of 3D Slicer-based reconstruction for preoperative identification of offending vessels in patients with vertebrobasilar dolichoectasia (VBD)-associated hemifacial spasm (HFS) undergoing microvascular decompression (MVD), and to investigate the prognostic value of dynamic intraoperative lateral spread response (LSR) assessment.

METHODS

This retrospective study included 176 patients with HFS who underwent MVD between June 2021 and February 2023; among them, 84 patients had VBD. All patients underwent preoperative 3D time-of-flight magnetic resonance angiography and 3D fast imaging employing steady-state acquisition magnetic resonance imaging, followed by 3D Slicer-based reconstruction. Intraoperative findings were used as the reference standard to compare conventional image assessment with 3D Slicer-based reconstruction for offending-vessel identification in patients with VBD. Postoperative outcomes, complications, and the associations of conventional LSR findings, dynamic intraoperative LSR findings, and immediate postoperative symptom relief with 1-year outcome were also analyzed.

RESULTS

In patients with VBD, the concordance rate with intraoperative findings for identification of a single offending vessel was significantly higher with 3D Slicer-based reconstruction than with conventional image assessment (88.37% vs. 60.47%, P = 0.006). For multiple offending vessels, the concordance rates were 81.08% and 62.16%, respectively (P = 0.121). Overall concordance rates were 82.14% and 58.33%, respectively (P = 0.001). The difficulty score for neurovascular relationship assessment was lower with 3D Slicer-based reconstruction than with conventional image assessment (0.369 ± 0.757 vs. 1.13 ± 0.915, P < 0.001). At 1 year, 78 of 84 patients in the VBD group achieved complete symptom resolution. Symptom relief did not differ significantly between the VBD and non-VBD groups at any follow-up time point (all P > 0.05). Postoperative hearing loss was more frequent in the VBD group (22.62% vs. 11.24%, P = 0.036), whereas facial palsy rates were comparable (P = 0.494). Within the VBD group, dynamic intraoperative LSR findings and immediate postoperative symptom relief were significantly associated with 1-year outcome (both P < 0.001), whereas conventional LSR findings were not (P = 0.683).

CONCLUSIONS

In VBD-associated HFS, 3D Slicer-based reconstruction improved offending-vessel identification and reduced the difficulty of preoperative neurovascular assessment. Dynamic intraoperative LSR findings, rather than conventional LSR findings, were associated with 1-year outcome and may represent a potentially useful prognostic indicator.