Augmented Reality-Assisted Microsurgery for Severe Thoracic Ossification of the Ligamentum Flavum: A Case Report.

Ossification of the ligamentum flavum (OLF) can lead to dural ossification, significantly increasing the risk of complications, including intraoperative nerve injury. The application of augmented reality (AR) and advanced digital technologies in spine surgery has the potential to reduce these risks. This case report highlights a perioperative nerve injury-free microsurgery using elastic image fusion technology, which integrates preoperative imaging with intraoperative computed tomography for a patient with severe stenotic OLF and dural ossification. A 68-year-old Japanese man presented with persistent right-sided back pain. Additionally, the patient reported mild gait instability and difficulty maintaining balance on uneven surfaces, which had progressively worsened over the past six months. Magnetic resonance imaging revealed severe OLF with 81% spinal canal stenosis. Given the risks of dural injury and cerebrospinal fluid leakage, a microsurgical procedure using AR was planned to ensure nerve protection. The surgery employed an image-guided navigation system with elastic image fusion to accurately align intraoperative and preoperative images. Additionally, microscopy enabled the real-time projection of preoperative images and navigation screens onto the surgical field. The procedure was successful, and the patient experienced no postoperative nerve damage. He regained walking stability and was discharged on the 28th postoperative day. At the two-year follow-up, he remained free of recurrences and neurological deficits. OLF with dural involvement poses a high risk of complications. In such complex cases, AR technology provides valuable intraoperative reference information, enhancing the safety and precision of spinal surgery.