Objectives:To establish a cadaveric model of ossification of posterior longitudinal ligament(OPLL)in thoracic spine and explore the feasibility of performing the endoscopic sink boat technique(SBT)for OPLL decompression on the cadaveric model.Methods:A fresh frozen cadaveric specimen was utilized.Under the guidance of a navigation robotic arm and CT,a puncture was made through the lateral thoracic wall into the posterior edge of the T9 vertebra,mimicking the pre-planned surgical trajectory.Once the puncture reached the midpoint of the venebral body,bone cement was injected to penetrate the spinal canal along the posterior longitudinal ligament.CT scans confirmed successful cement distribution behind the T9 vertebra,simulating OPLL preparation.Subsequently,the endoscopic SBT was performed by entering the vertebral body through the ipsilateral intervertebral foramen and the contralateral partial pedicle.Bilateral center-directed resection of the vertebral body created a trough-like defect accommodating the simulated OPLL.Using suture anchors,the OPLL mass was anchored,sunk,and secured within the vertebral trough to achieve ventral decompression of the spinal canal.Results:A bone cement model of thoracic OPLL in cadaveric specimen was successfully established with the simulated OPLL occupying 49％of the posterior margin of the T9 vertebra.Endoscopic SBT surgery smoothly decompressed the ventral side of the thoracic spinal cord,and postoperative CT scans confirmed the simulated OPLL was successfully embedded and fixed within the vertebra using the endoscopic SBT technique,with a sagittal diameter restoration rate of 218％.Conclusions:Endoscopic SBT is an innovative thoracic endoscopic technique,which has demonstrated in cadavers to achieve decompression of the spinal canal by sinking simulated segmental thoracic OPLL into the vertebral body.