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Subcutaneous Trigeminal Nerve Field Stimulation for Refractory Facial Pain
Published on: May 10, 2017
Quantitative intraoperative lateral spread response amplitudes in hemifacial Spasm: Associations with vascular burden
Minsoo Kim1, Soung Wook Park2, Hyun Seok Lee2
1Department of Neurosurgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, the Republic of Korea.
Objective:
To determine whether intraoperative lateral spread response (LSR) amplitudes reflect vascular burden and configuration in hemifacial spasm.
Methods:
We retrospectively reviewed consecutive microvascular decompressions at a single center. LSR I (mentalis) and LSR II (frontalis) were recorded using a standardized protocol. The primary exposure was arterial vessel count (single vs. multiple); vein-only cases were exploratory owing to imbalance. Amplitudes and derived indices (I/II ratio, I-II difference) were compared using variance-aware parametric and nonparametric tests.
Results:
LSRs were obtained in most patients. LSR I exceeded LSR II with a significant paired effect. Arterial burden showed a graded pattern in LSR I, with higher amplitudes in multiple-vessel compression; however, differences across vessels counts were not significant after adjustment. No differences were observed for LSR II. Derived indices better reflected vascular burden, showing significant contrasts where raw amplitudes did not, including single-versus-multiple comparisons. Vein-only cases appeared lower but remained exploratory.
Conclusions:
Intraoperative LSR amplitudes, especially at the mentalis muscle, reflect arterial burden, and derived indices improve discrimination. Findings support amplitude-based monitoring, with multicenter studies needed to confirm underlying mechanisms and predictive utility.
Significance:
LSR monitoring offers a practical marker of vascular burden, potentially guiding surgical decisions and improving outcomes.
