Objective: Adjacent vertebral fractures (AVFs) are frequent in the early postoperative period following balloon kyphoplasty (BKP) for osteoporotic vertebral fractures (OVFs); however, the mechanism remains unclear. This study aimed to elucidate the mechanism of AVF by comparing early radiographic changes in patients with and without AVF. Methods: Sixty-three patients who underwent BKP within 60 days of OVF onset and were followed for at least 3 months postoperatively were included. Patients were divided into AVF and non-AVF groups. Comparative analyses were conducted for demographics, volume of bone cement injected, and radiological assessments presurgery, postsurgery, 1 and 2 weeks postoperatively, and at final follow-up. Key radiographic parameters, including vertebral kyphotic angle (VKA) and anteroposterior vertebral height ratio (A/P ratio), were evaluated between the groups. Results: AVF occurred in 8 out of 63 patients (12.7%). Demographics and bone cement volume showed no significant differences between groups. Radiographic analysis revealed earlier VKA deterioration in the non-AVF group, with significant differences at 2 weeks postoperatively. In the AVF group, VKA and the A/P ratio showed more pronounced changes from preoperative to postoperative measurements. The change in the A/P ratio was significantly greater in the AVF group than in the non-AVF group. Conclusions Vertebral correction deteriorated earlier in the non-AVF group, while BKP resulted in a more substantial correction of vertebral bodies in the AVF group. These findings suggest that the mechanical stability achieved by BKP may contribute to the differential progression of AVF, highlighting the need for tailored postoperative management.

Stiff-person syndrome (SPS) is an extremely rare disease that is characterised by progressive rigidity and muscle spasms affecting the axial and limb muscles and is difficult to diagnose. In SPS, autoantibodies such as anti-GAD antibody or anti-amphiphysin antibody may be proved, and it is speculated that SPS is GABAergic neurons disorder with the central nervous system due to these antibodies. We report a case of advanced breast cancer with a paraneoplastic SPS. Case: A 52-year-old woman was diagnosed with advanced breast cancer with bilateral multiple lung metastases, bilateral cancerous pleurisy, multiple liver metastases, cancerous peritonitis, and bilateral ovarian metastases. Anti-cancer treatment was not indicated due to poor condition, and oxygenation and pleural drainage and ascites drainage were performed in the palliative care unit. A series of symptoms due to muscle rigidity progressed rapidly which initially manifested as dysphagia, then stiffness of the upper extremities and locomotive disability. So she was diagnosed as paraneoplastic SPS by a neurologist. Despite the partial efficacy of diazepam, it was difficult to increase dosage due to sedation.