Temporal muscle thickness and area are an independent prognostic factors in patients aged 75 or younger with aneurysmal subarachnoid hemorrhage treated by clipping

Abstract

Background: Skeletal muscle mass is an important factor for various diseases' outcomes. As for its indicators, temporal muscle thickness (TMT) and temporal muscle area (TMA) on the head computed tomography are useful, and TMT and TMA were reported as potential prognostic factors for aneurysmal subarachnoid hemorrhage (SAH). We examined the clinical characteristics, including TMT and TMA, of SAH patients aged 75 or younger.

Methods: We retrospectively investigated 127 SAH patients with all World Federation of Neurosurgical Societies (WFNS) grades and treated by clipping between 2009 and 2019. Clinical outcome was measured with the modified Rankin Scale (mRS) at 6 months, with favorable outcome defined as mRS 0-2. The associations between the clinical variables and the outcomes were analyzed.

Results: The mean age was 60.6 (32-74) years, and 65% were women. The mean ± standard deviation of WFNS grade was 2.8 ± 1.4. TMT and TMA were larger in the favorable outcome group than the poor one. Multivariate analysis revealed that age, smoking, WFNS grade, and TMT or TMA were associated with favorable outcome. Receiver operating characteristic analysis found that the threshold of TMT was 4.9 mm in female and 6.7 mm in male, and that of TMA was 193 mm² in female and 333 mm² in male.

Conclusion: The odds ratios for TMT and TMA related to clinical outcome were lower than for smoking and WFNS grade; however, on multivariate analysis they remained independent prognostic factors in SAH patients aged 75 or younger treated by clipping. Further studies are needed to confirm these findings.

Keywords: Cerebral aneurysm; Clipping; Prognostic factor; Sarcopenia; Subarachnoid hemorrhage; Temporal muscle thickness and area.

Figure 1:

Head CT image measuring temporal muscle thickness (TMT) and area (TMA). The slice is 5 mm above the superior wall of the orbit (a). The rectangular part in (a) is enlarged in (b) and (c). CT image representing TMT. The line between the arrows indicates TMT (b). CT image representing TMA (c). Patient with a large TMT and TMA (d); patient with a small TMT and TMA (e).

Figure 2:

Temporal muscle thickness (TMT) was significantly larger in the favorable outcome groups than in the poor outcome groups (P = 0.001 in both sex, P = 0.007 in female, P = 0.007 in male, respectively) (a). Temporal muscle area (TMA) was also significantly larger in the favorable outcome groups (P = 0.005 in both sex, P = 0.007 in female, P = 0.040 in male, respectively) (b). Receiver operating characteristic (ROC) analysis was performed to determine the threshold of the TMT and TMA for outcomes. The threshold of TMT was 4.9 mm in female (sensitivity = 0.661, specificity = 0.750. AUC = 0.703, 95%CI 0.523–0.811, P = 0.003) and 6.7 mm in male (sensitivity = 0.647, specificity = 0.909. AUC = 0.767, 95%CI 0.602–0.933, P = 0.008) (c). The threshold of TMA was 193 mm² in female (sensitivity = 0.729, specificity = 0.700. AUC = 0.699, 95%CI 0.536–0.813, P = 0.024) and 333 mm² in male (sensitivity = 0.735, specificity = 0.727. AUC = 0.699, 95%CI 0.521–0.878, P = 0.049) (d).