Abstract: Objective To analyze the clinical effect of spinal cord decompression and lavage therapy on chronic cervical spinal cord injury and explore the possible mechanism. Methods Fifty-seven patients with chronic cervical spinal cord injury treated in our hospital from January, 2008 to January, 2015 were enrolled, including 17 with multilevel cervical disc herniation, 25 with long segmental ossification of the posterior longitudinal ligament, 13 with hypertrophy or calcification of neck ligamentum flavum, and 2 with old cervical fractures. Open-door spinal canal laminoplasty via a posterior approach and decompression in simple extramedullary decompression was performed in 31 cases (group A), and open-door spinal cord incision decompression via a posterior approach, saline irrigation, and spinal canal laminoplasty in intramedullary decompression was performed in 26 cases (group B). The pre-operative cerebrospinal fluid in group B patients was collected to examine the inflammatory factors. All the patients were followed up and evaluated for pre- and postoperative JOA scores to calculate the improvement rate with regular examinations by X-ray, CT or MRI. Results Imaging examinations 2 weeks after the operation showed obvious relief of the primary lesion in both groups, and the improvement of high signals was better in group B than in group A. The mean improvement rate at 12 months after the operation was 52.33% in group A and 61.52% in group B (P<0.05), and the mean JOA score was significantly higher in group B than in group A (14.80±1.51 vs 13.58±0.56; P<0.05). Cerebrospinal fluid leakage occurred in 3 cases, epidural hematoma in 2 cases, internal fixation loosening in 1 case in group A; portal shaft fracture and internal fixation loosening occurred in 1 case in group B. Postoperative recovery time was shorter in group B and entered the platform phase in 3 months. The inflammatory factors IFN-γ, IL-17F, IL-6 and sCD40L were all significantly higher than the normal levels after spinal cord injury, and the increment of IL-6 was the most conspicuous (P<0.05). Conclusion Intramedullary and extramedullary decompression can achieve better outcomes than extramedullary decompression in patients with chronic cervical cord injury. This may be related not only to relieving adhesions and secondary compression by cutting the dura under the microscope, but also to removal of local inflammatory factors.