Feasibility and early clinical outcomes of endoscopic trans-pedicular approach for ventral central rigid compression of cervical spinal cord

English Keywords:Cervical spondylotic myelopathy  Trans-pedicular approach  Trans-osseous endoscopic surgery  Ossification of posterior longitudinal ligament  Ventral central rigid compression of spinal cord

English Abstract:

  【Abstract】 Objectives: To evaluate the feasibility, safety, and early clinical efficacy of trans-pedicular approach (TPA) endoscopic decompression for the treatment of ventral central hard compression of the cervical spinal cord. Methods: The anatomical parameters related to TPA at C3-C7 levels were measured, and the feasibility rate of a 7-mm-diameter bone tunnel was assessed. Finite element biomechanical simulation was performed to analyze changes in cervical range of motion and bone stress distribution after TPA. A ventral central hard compression model of the spinal cord was created by injecting bone cement into the posterior aspect of the vertebral bodies of cadaveric cervical spine specimens, followed by simulated TPA surgery under endoscopic guidance to observe whether decompression could be achieved. Clinical data of 15 patients with cervical spondylotic myelopathy(CSM) who underwent TPA endoscopic surgery between January 2020 and January 2022 were retrospectively analyzed. The operative time, intraoperative blood loss, and surgery-related complications were recorded. The Japanese Orthopaedic Association(JOA) score and neck pain visual analog scale(VAS) score were assessed preoperatively and postoperatively, and CT and MRI were used to evaluate healing of the lateral mass bone defect and changes in spinal cord compression. All patients were followed up for at least 12 months. Results: The feasibility rate of a 7-mm bone tunnel was 100% at C3-C5, 93.33% at C6, and 20% at C7. Biomechanical simulation showed that during cervical extension after TPA, the peak stress at the operated pedicle was significantly higher than that in the non-operated group, whereas the range of motion at the operated segment showed no significant difference from the preoperative state. In the cadaveric model, injection of bone cement resulted in a stable ventral hard compression, which was successfully relieved by simulated TPA surgery under endoscopy. All 15 patients underwent surgery successfully without intraoperative or postoperative neurovascular complications. The mean operative time was 121.3±20.3min (range, 80-150min), and the mean intraoperative blood loss was 41.7±28.3mL(range, 5-80mL). At 12 months postoperatively, the JOA score improved from 12.2±1.7 to 16.0±1.2, and the neck VAS score decreased from 6.5±1.9 to 2.9±1.1(both P<0.001). At the final follow-up, CT showed a significant reduction in the lateral mass bone defect, and MRI demonstrated effective decompression of the ventral spinal cord at the operated segment. Conclusions: Cervical endoscopic TPA has anatomical feasibility, conforms to biomechanical principles, and possesses good surgical operability. Preliminary clinical application suggests that this approach is safe and effective for treating CSM caused by ventral central hard compression, with satisfactory early outcomes.