Effect of differences in proximal neck angles on biomechanics of abdominal aortic aneurysm based on fluid dynamics.

BACKGROUND: This study aimed to analyze the effect of proximal neck angulation on the biomechanical indices of abdominal aortic aneurysms (AAA) and to investigate its impact on the risk of AAA rupture. METHODS: CT angiography (CTA) data of patients with AAA from January 2015 to January 2022 were collected. Patients were divided into three groups based on the angle of the proximal neck: Group A (âˆ ß ≤ 30°), Group B (30°<âˆ ß ≤ 60°), and Group C (âˆ ß > 60°). Biomechanical indices related to the rupture risk of AAA were analyzed using computational fluid dynamics modeling (CFD-Post) based on the collected data. RESULTS: Group A showed slight turbulence in the AAA lumen with a mixed laminar flow pattern. Group B had a regular low-speed eddy line characterized by cross-flow dominated by lumen blood flow and turbulence. In Group C, a few turbulent lines appeared at the proximal neck, accompanied by eddy currents in the lumen expansion area following the AAA shape. Significant differences were found in peak wall stress, shear stress, and the maximum blood flow velocity impact among the three groups. The maximum blood flow velocity at the angle of the proximal neck impact indicated the influence of the proximal neck angle on the blood flow state in the lumen. CONCLUSION: As the angle of the proximal neck increased, it caused stronger eddy currents and turbulent blood flow due to a high-speed area near the neck. The region with the largest diameter in the abdominal aortic aneurysm was prone to the highest stress, indicating a higher risk of rupture. The corner of the proximal neck experienced the greatest shear stress, potentially leading to endothelial injury and further enlargement of the aneurysm.

A Retrospective Comparison of Clinical Efficacy between Multimodal Analgesia and Patient-Controlled Epidural Analgesia in Patients Undergoing Total Knee Arthroplasty.

Background and Objectives: Adequate pain management during early rehabilitation is mandatory for improving the outcomes of patients undergoing total knee arthroplasty (TKA). Conventional pain management, mainly comprising opioids and epidural analgesia, may result in certain adverse effects such as dizziness, nausea, and motor blockade. We proposed a multimodal analgesic (MA) strategy involving the use of peripheral nerve block (NB), periarticular injection (PAI), and intravenous patient-controlled analgesia (IVPCA). This study compared the clinical efficacy and adverse effects of the proposed MA strategy and patient-controlled epidural analgesia (PCEA). Materials and Methods: We enrolled 118 patients who underwent TKA under spinal anesthesia. The patients followed either the MA protocol or received PCEA after surgery. The analgesic effect was examined using a numerical rating scale (NRS). The adverse effects experienced by the patients were recorded. Results: A lower proportion of patients in the MA group experienced motor blockade (6.45% vs. 22.98%) compared to those in the PCEA group on the first postoperative day. Furthermore, a lower proportion of patients in the MA group experienced numbness (18.52% vs. 43.33%) than those in the PCEA group on the first postoperative day. Conclusions: The MA strategy can be recommended for reducing the occurrence of motor blockade and numbness in patients following TKA. Therefore, the MA strategy ensures early rehabilitation while maintaining adequate pain relief.

Comparison of minimally invasive transforaminal lumbar interbody fusion and midline lumbar interbody fusion in patients with spondylolisthesis.

BACKGROUND: This study aimed to compare surgical outcomes, clinical outcomes, and complications between minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) and midline lumbar interbody fusion (MIDLIF) in patients with spondylolisthesis. METHODS: This study retrospectively compared the patients who underwent MIS TLIF (n = 37) or MIDLIF (n = 50) for spinal spondylolisthesis. Data of surgical outcomes (postoperative one-year fusion rate and time to bony fusion), clinical outcomes (visual analog scale [VAS] for pain and Oswestry Disability Index [ODI] for spine function), and complications were collected and analyzed. RESULTS: There was more 2-level fusion in MIDLIF (46% vs. 24.3%, p = 0.038). The MIS TLIF and MIDLIF groups had similar one-year fusion rate and time to fusion. The MIDLIF group had significantly lower VAS at postoperative 3-months (2.2 vs. 3.1, p = 0.002) and postoperative 1-year (1.1 vs. 2.1, p = < 0.001). ODI was not significantly different. The operation time was shorter in MIDLIF (166.1 min vs. 196.2 min, p = 0.014). The facet joint violation is higher in MIS TLIF (21.6% vs. 2%, p = 0.009). The other complications were not significantly different including rate of implant removal, revision, and adjacent segment disease. CONCLUSION: In this study, postoperative VAS, operation time, and the rate of facet joint violation were significantly higher in the MIS TLIF group. Comparable outcomes were observed between MIDLIF and MIS TLIF in terms of fusion rate, time to fusion, and postoperative ODI score.

Unplanned emergency department visits within 90 days of hip hemiarthroplasty for osteoporotic femoral neck fractures: Reasons, risks, and mortalities.

Objectives: Bipolar hemiarthroplasty is commonly performed to treat displaced femoral neck fractures in osteoporotic patients. This study aimed to assess the occurrence and outcomes of unplanned return visits to the emergency department (ED) within 90 days following bipolar hemiarthroplasty for displaced femoral neck fractures. Methods: The clinical data of 1322 consecutive patients who underwent bipolar hemiarthroplasty for osteoporotic femoral neck fractures at a tertiary medical center were analyzed. Data from the patients' electronic medical records, including demographic information, comorbidities, and operative details, were collected. The risk factors and mortality rates were analyzed. Results: Within 90 days after surgery, 19.9% of patients returned to the ED. Surgery-related reasons accounted for 20.2% of the patient's returns. Older age, a high Charlson comorbidity index score, chronic kidney disease, and a history of cancer were identified as significant risk factors for unplanned ED visits. Patients with uncemented implants had a significantly greater risk of returning to the ED due to periprosthetic fractures than did those with cemented implants (P = 0.04). Patients who returned to the ED within 90 days had an almost fivefold greater 1-year mortality rate (15.2% vs 3.1%, P < 0.001) and a greater overall mortality rate (26.2% vs 10.5%, P < 0.001). Conclusions: This study highlights the importance of identifying risk factors for unplanned ED visits after bipolar hemiarthroplasty, which may contribute to a better prognosis. Consideration should be given to the use of cemented implants for hemiarthroplasty, as uncemented implants are associated with a greater risk of periprosthetic fractures.