Vertebroplasty or kyphoplasty is a widely accepted minimally invasive procedure for treating painful vertebral compression fractures. Although considered safe, rare but serious complications such as spinal subdural hematoma (SDH) can occur, particularly in patients receiving long-term anticoagulation therapy. We present a rare case of spinal SDH following kyphoplasty in a 78-year-old woman with a mechanical aortic valve on chronic warfarin therapy. Anticoagulation was managed perioperatively with warfarin discontinuation and bridging enoxaparin. Postoperative X-ray showed subtle posterior cement leakage. MRI on postoperative day 1 revealed lumbar SDH, which progressed cranially by day 2. The patient remained neurologically intact and was treated conservatively with corticosteroids and temporary suspension of anticoagulation. Follow-up imaging showed gradual hematoma resolution, and she was discharged without deficits. This case suggests the importance of maintaining a high index of suspicion for spinal hematoma in anticoagulated patients, especially when new symptoms or even minor cement leakage are present. Careful perioperative planning, including early imaging and multidisciplinary management, is crucial in such high-risk patients.