A Comparative Study On Efficacies Of Posterior Mini-open And Open Surgery For Thoracolumbar Burst Fractures With Severe Spinal Canal Stenosis

Objective: To compare efficacies of minimal invasive decompression by posterior microscopic mini-open technique(MOT)and posterior open surgery in patients with severe spinal canal stenosis resulting from AO Type A3 and A4 thoracolumbar burst fractures.Methods: A retrospectively comparative study on the clinical materials of 64 patients with severe spinal canal stenosis caused by AO Type A3 and A4 thoracolumbar burst fractures and treated in our department between January 2012 and January 2016.Patients were treated by a procedure,MOT,which performed unilateral or bilateral laminectomy assisted with microscope,poking reduction,intervertebral bone graft via spinal canal and percutaneous pedicle screw fixation by mini-open posterior approach as test group(group T,n=28),followed-up 12~24 months.While patients treated by posterior open surgery as control group(group C,n=36),followed-up 12~24 months.To assess clinical efficacies by inter-group comparison of blood loss,hospitalization time,operation time,and by intra-group comparison of American Spinal Injury Association(ASIA)grading at preoperative and last follow-up,and by intra-and inter-group comparison of preoperative,postoperative and last follow-up the visual analogue scale(VAS),percentage of anterior height of injured vertebrae(PAHIV),Cobb angle and rate of spinal compromise(RSC).Results: All the 64 patients were performed procedures successfully.The wounds healed primarily,without complications such as wound infection,cerebrospinal fluid leakage and failure in internal fixation.Group T: the average hospitalization time was 12.54±3.04 days,average operation time was 216.39±38.11 minutes,and average blood loss was 197.68±136.15 m L.Group C: the average hospitalization time was 13.89±3.76 days,average operation time was 165.22±24.15 minutes,and average blood loss was 340±150.54 m L.There was no significant difference in the hospitalization time in two groups(P>0.05).In group T,the operation time was longer(P<0.05),but the blood loss was smaller than those in group C(P<0.05).The radiological examinations showed all the fractures in two groups had healed.The PAHIV,Cobb angle,RSC at immediately after operation and at last follow-up in two groups were improved when compared with preoperative ones(P<0.05).The PAHIV,Cobb angle at immediately after operation without difference in those at last follow-up in two groups(P>0.05).And the RSC at last follow-up was improved when compared with that at immediately after operation in two groups(P<0.05).Compared among groups,there was no difference in the PAHIV,Cobb angle,RSC at immediately after operation(P>0.05).At last follow-up,the PAHIV in two groups without difference(P>0.05),RSC in group C was better than in group T(P<0.05),and Cobb angle in group T preferably preserved than that in group C(P<0.05).The preoperative VAS in two groups had no significant difference(P>0.05).The VAS at 1 day after operation and at last follow-up in two groups were improved when compared with preoperative ones(P<0.05).The VAS at different time points after operation in group T,preferably improved than those in group C(P<0.05).ASIA grading at last follow-up in two groups were improved,compared with preoperative ones(P<0.05).Conclusion: MOT and posterior open surgery are effective treatments for AO Type A3 and A4 thoracolumbar burst fractures with severe spinal canal stenosis.MOT is more accurate for spinal canal decompression,with less blood loss,and obvious pain relief.We recommend to choosing MOT as priority selection for patients who suffered Type A3 and A4 thoracolumbar burst fractures with severe spinal canal stenosis.