Metastatic renal cell carcinoma of the lumbar spine with long posterior instrumented fusion and repetitive dislodgement of the set screws of the S2 alar-iliac screw

Background

S2 alar-iliac screws (S2AIS) are widely used to anchor the pelvis to a lumbar fusion. Here, we report a patient who experienced repetitive dislodgement of the set screws of the S2AIS following a posterior instrumented fusion.

Case Description

A 68-year-old male presented with an L3 metastasis and L2-L3 subluxation attributed to renal cell cancer. Following an L2-L5 posterior decompression and T9-pelvic fusion utilizing bilateral S2AIS fixation, the set screws of the S2AIS repeatedly dislodged, requiring two additional operations. The final surgery required multiple anchors to the ilium and provided adequate fixation until the patient's expiration.

Conclusion

The set screw fixing force was weaker than the fixing force of the S2AIS; multiple iliac anchors effectively salvaged this condition.

P10 A possible link between sarcopenia and major bleeding risk among patients with atrial fibrillation treated with oral anticoagulation undergoing coronary stenting

Background/Introduction

In patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) with stent implantation, oral anticoagulation (OAC) plus dual antiplatelet therapy (DAPT) increases the risk of bleeding. The PRECISE-DAPT (P-DAPT) and DAPT scores were created to predict increased bleeding versus ischemic risk in patients undergoing DAPT. However, not much information is available on predicting bleeding risk associated with OAC concomitant with DAPT in patients with AF treated with coronary stents. Physical frailty or sarcopenia is considered an emerging predictor for bleeding in AF patients.

Purpose

To investigate the relationship between skeletal muscle mass and major bleeding risk in AF patients undergoing PCI and subsequent OAC and DAPT.

Methods

A total of 1,234 consecutive patients after PCI using newer-generation drug eluting stents were evaluated. An anti-thrombotic regimen without OAC was given to 1,077 patients, whereas OAC was required in 157 patients (12.7%) including AF (n = 96). The P-DAPT, DAPT, and HAS-BLED scores were calculated for each of the patients. Any out-of-hospital major bleeding events were identified based on BARC criteria during a median follow-up of 2.9 years. The fat-free mass index (FFMI; kg/m2) was calculated to evaluate skeletal muscle mass as follows: (7.38 + 0.02908 × urinary creatinine (mg/day)) / (height squared (m2)). A Cox proportional hazards model was used to test the significance of the FFMI and these risk scores as predictors of major bleeding, defined as BARC 3 or 5 events in AF patients. The receiver operating characteristic curve (ROC) analyses were used to examine the predictive ability of the FFMI and these scores to identify patients with major bleeding events.

Results

Major bleeding events were observed in 9 (9.3%) patients. Major bleeding was associated with a lower FFMI (hazard ratio [HR] 0.53; 95% confidence interval [CI] 0.36-0.79; p = 0.002), and higher P-DAPT score (HR, 1.07; 95% CI, 1.02-1.11; p = 0.003), but not with the DAPT (HR, 0.71; 95% CI, 0.45-1.12; p = 0.147) and the HAS-BLED score (HR, 1.00; 95% CI, 0.48-2.09; p = 0.990). In the non-OAC cohort, major bleeding was related to a higher P-DAPT score (HR, 1.05; 95% CI, 1.02-1.07; p < 0.0001), but the FFMI (HR, 0.89; 95% CI, 0.73-1.09; p = 0.265) and the DAPT score were not correlated. C-statistics for major bleeding events were 0.82 (95% CI, 0.71-0.93, p = 0.001) for the FFMI and 0.79 (95% CI, 0.68-0.90, p = 0.004) for the P-DAPT score.

Conclusions

Assessment of the FFMI for screening sarcopenia is useful to predict major bleedings specifically in patients with AF undergoing coronary stenting. Both the FFMI and P-DAPT could successfully predict major bleedings in AF patients after PCI. Whether novel bleeding risk scores combined with measuring body composition adequately identify high risk patients needs to be validated.

Improvement in Classification of Tactile Event-Related Potentials using Random-Interval Tasks∗

The classification accuracy of an event-related potential (ERP) induced by a tactile stimulus is investigated to create a brain-computer interface (BCI). Mechanical tactile stimuli were applied to the left and right index fingers using two piezo actuator probes that were used as a Braille display for the visually impaired. In an experiment, two-class classification was investigated using three kinds of tactile stimulus pattern. The subjects were instructed to pay attention to unusual target stimuli while avoiding other frequent nontarget stimuli. The extracted features were classified using stepwise linear discriminant analysis. As a result, high accuracy was obtained by the task of random intervals compared with the task of constant intervals. It was suggested that the accuracy of the BCI using tactile stimuli is influenced by the concentration on the task.