D-Line Predicts When Posterior Longitudinal Cervical Ligament Ossification In Cervical 3-4 Occupancy Should Be Expanded And Decompressed Toward The Cephalade

Objective:To analyze the correlation between D-line staging and the choice of surgical approach in patients with posterior longitudinal ligament ossification with varying degrees of compression-causing material in C3-4 segments and their postoperative outcomes.Methods:A total of 19 patients underwent posterior cervical single-opening spinal canal enlargement surgery,including 14 patients who underwent C3-7 single-opening surgery and 5 patients who underwent C3-7 enlargement and decompression of the inferior edge of the C2 vertebral plate.The patients were divided into D-line(+)and D-line(-)groups according to whether the D-line passed through the anterior compressor of C3-4.The clinical efficacy was evaluated using the Japanese Orthopaedic Association Scores(JOA)and the recovery rate,and the imaging evaluation was performed using the median sagittal diameter of the spinal canal,anterior spinal cord space,spinal cord diameter,spinal cord distension,and spinal cord posterior displacement distance,spinal cord posterior displacement distance,etc.The correlation between the D-line subgroup,the manual subgroup,and the imaging subgroup was also compared.Results:There were no statistical differences in the preoperative JOA scores;preoperative C2-7 anterior convexity angle;C3-4 segmental compressibility size;preoperative and postoperative median sagittal diameter of the spinal canal;preoperative and postoperative anterior spinal cord clearance;preoperative and postoperative mean spinal cord diameter;postoperative spinal cord posterior displacement;mean spinal cord distension and mean postoperative overall spinal cord posterior displacement distance between the two groups classified by D-line(P > 0.05).The postoperative JOA scores(14.00±0.75 in the D(+)group and 13.38±0.65 in the D(-)group)and their improvement rates(65.31±8.48 in the D(+)group and 57.43±6.07 in the D(-)group)were better in the D(+)group than in the D(-)group,and there was a statistical difference between them(P< 0.05).There was no statistical significance(P > 0.05)between the D-line subgroup and the imaging subgroup,but there was a statistical difference between them and the surgical subgroup(P < 0.000).Conclusion:The D-line can provide a degree of reference for clinical surgical decision making.The findings suggest that in patients with posterior longitudinal ligament ossification in the cervical spine with varying degrees of compressibility in the C3-4 segment,if the preoperative D-line(+)is present,intraoperative decompression should be expanded toward the cervical 2 vertebral plate to achieve better clinical outcomes.