Methods: Cases of 50 patients with ASD who underwent long spinal fusion (>9 levels) with S2AI screws were retrospectively reviewed. Loosening of S2AI screws and S1 pedicle screws and bone fusion at the level of L5–S1 at 2 years after surgery were investigated using computed tomography. In addition, risk factors for loosening of S2AI screws were determined in patients with ASD. Results: At 2 years after surgery, 33 cases (66%) of S2AI screw loosening and six cases (12%) of S1 pedicle screw loosening were observed. In 40 of 47 cases (85%), bone fusion at L5–S1 was found. Pseudarthrosis at L5–S1 was not significantly associated with S2AI screw loosening (19.3% vs. 6.3%, p=0.23), but significantly higher in patients with S1 screw loosening (83.3% vs. 4.9%, p<0.001). On multivariate logistic regression analyses, high upper instrumented vertebra (UIV) level (T5 or above) (odds ratio [OR], 4.4; 95% confidence interval [CI], 1.0–18.6; p=0.045) and obesity (OR, 11.4; 95% CI, 1.2–107.2; p=0.033) were independent risk factors for S2AI screw loosening. Conclusions High UIV level (T5 or above) and obesity were independent risk factors for S2AI screw loosening in patients with lumbosacral fixation in surgery for ASD. The incidence of lumbosacral fusion is associated with S1 screw loosening, but not S2AI screw loosening.

In acute Stanford type A aortic dissection, except for some thrombosed false-lumen types, graft replacement is a standard treatment. On the other hand, thoracic endovascular aortic repair (TEVAR) might be considered for high-risk patients with retrograde type A aortic dissection when entry is in the descending aorta, although its efficacy in a case of an extensive thrombosed false lumen without obvious entry is unknown. We report a case of successful zone 3 TEVAR using RelayPro NBS for Stanford type A aortic dissection with a localized CT-enhanced false lumen in the proximal descending aorta. An 83-year-old woman was admitted for acute Stanford type A aortic dissection with a thrombosed false lumen of the ascending thoracic aorta. She was initially treated conservatively because of being a high-risk patient for open surgery. One week after hospitalization, the ascending aorta diameter increased and the false lumen in the proximal descending aorta grew sporadically in a CT image. We suspected that the ascending aorta was enlarged due to a partially patent false lumen of the descending thoracic aorta, and performed zone 3 TEVAR using RelayPro NBS to close a possible entry in the proximal descending aorta even though there was no obvious entry. The patient had a good postoperative course and was discharged 15 days after TEVAR. Shrinkage of the false lumen in the ascending aorta was observed in CT images two months after TEVAR.