Abstract
Objective Suprameatal tubercle (SMT), a bony prominence located above the internal acoustic
meatus, is reported to impede the microscopic view during microvascular decompression
(MVD) for trigeminal neuralgia (TN). For an enlarged SMT, removal of the SMT may be
required in addition to the routine MVD to precisely localize the offending vessels.
The objective of this study is to investigate the predictive factors influencing the
requirement of SMT removal during trigeminal MVD.
Methods We retrospectively reviewed 197 patients who underwent MVD for TN, and analyzed the
correlation of the SMT height and other clinicosurgical data with the necessity to
remove the SMT during MVD. The parameters evaluated in the statistical analyses included
maximum SMT height, patient's clinical characteristics, surgical data including the
type and number of offending vessels, and surgical outcomes.
Results SMT removal was required for 20 patients among a total of enrolled 197 patients.
In the univariate analysis, maximum SMT height, patient's age, and number (≥ 2) of
offending vessels were associated with the requirement for SMT removal. Multivariate
analysis with binary logistic regression revealed that the maximum SMT height and
number (≥ 2) of offending vessels were significant factors influencing the necessity
for SMT removal. A receiver operating characteristic curve analysis revealed that
an SMT height ≥ 4.8 mm was the optimal cutoff value for predicting the need for SMT
removal.
Conclusion Large SMTs and the presence of multiple offending vessels are helpful in predicting
the technical difficulty of trigeminal MVD associated with the necessity of SMT removal.
Keywords
suprameatal tubercle - trigeminal neuralgia - microvascular decompression - petrous
bone - offending vessels
