Clinical Research For Postoperative Subsidence After Unilateral Pedicle Screw Fixation

Objective:1. To analyze clinical and radiological results of pedicle screw fixation and interbody fusion in degenerative lumbar disorders.2. To instigate postoperative risk factors affecting subsidence after unilateral pedicle screw fixation and interbody fusion.Methods:1. A clinical study was performed from 2009 to 2011, and patients with degenerative lumbar disorders were divided into the unilateral or bilateral pedicle screw fixation group based on operative method, moreover, patients were categorized into the subsidence and nonsubsidence groups based on radiological results.2. Risk factors such as age,sex,diagnosis,blood loss and or so were recorded and analyzed statistically. Clinical effect was evaluated with VAS?ODI and JOA scores,while mean disc height of fused segments?LLA and LSA were analyzed with GE Medical System for radiological assessment.Results:1. A certain degree of subsidence after surgery,which was not correlative with clinical effect,would be found within unilateral and bilateral groups.2. L5/S1 level of cage and elder patients may be linked to lack of symptom relief.Conclusions:Unilateral pedicle screw fixation and interbody cage is safe for lumbar degenerative diseases, and a certain degree of subsidence after surgery would be occurred while which is not correlative with clinical effect. L5/S1 level of cage and elder patients are identified as risk factors of cage subsidence.