Several anatomical variations of the radial artery have been described in the literature. Common variations include radial artery loop, recurrent branch, and anastomotic channels connecting the radial and brachial arteries. These variations can pose significant technical challenges to safe radial artery catheterization. Because radial access for neurointervention is becoming popular, appreciation of these variations and mastery of techniques for safe radial artery catheterization are of paramount importance. In this operative video,(video 1) we present a case of a 75-year-old man who underwent middle meningeal artery embolization for treatment of chronic subdural hematoma using a transradial approach. The patient was found to have a radial artery loop and a recurrent branch off the radial artery. The loop could not be negotiated with the conventional technique. We therefore used a microcatheter system with a stiff microwire to navigate and straighten the radial loop under road map guidance. The remaining procedure was performed successfully.

BACKGROUND:Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) can be catastrophic complications associated with adult spinal deformity (ASD) surgery. These complications are markedly influenced by osteoporosis, leading to additional vertebral fracture and pedicle screw loosening. The MRI-based vertebral bone quality score (VBQ) is a newly developed tool that can be used to assess bone quality.OBJECTIVE:To investigate the utility of the VBQ score in predicting PJK and/or PJF (PJF/PJK) after ASD correction.METHODS:We conducted a retrospective chart review to identify patients age ≥50 years who had received ASD surgery of 5 or more thoracolumbar levels. Demographic, spinopelvic parameters, and procedure-related variables were collected. Each patient's VBQ score was calculated using preoperative T1-weighted MRI. Univariate analysis and multivariate logistic regression were performed to determine potential risk factors of PJK/PJF. Receiver operating characteristic analysis and area-under-the-curve values were generated for prediction of PJK/PJF.RESULTS:A total of 116 patients were included (mean age, 64.1 ± 6.8 years). Among them, 34 patients (29.3%) developed PJK/PJF. Mean VBQ scores were 3.13 ± 0.46 for patients with PJK/PJF and 2.46 ± 0.49 for patients without, which was significantly different between the 2 groups (P < .001). On multivariate analysis, VBQ score was the only significant predictor of PJK/PJF (odds ratio = 1.745, 95% CI = 1.558-1.953, P < .001), with a predictive accuracy of 94.3%.CONCLUSION:In patients undergoing ASD correction, higher VBQ was independently associated with PJK/PJF occurrence. Measurement of VBQ score on preoperative MRI may be a useful adjunct to ASD surgery planning.