the goals of surgical treatment for thoracolumbar burst fractures are to restore vertebral column stability and to decompress neural elements4 ) . due to several problems associated with extensive long - level instrumentation , posterior short - segment instrumentation has been recently preferred for the treatment of thoracolumbar burst fractures in cases mild communition or load sharing score5 ) . because , a fracture with mild communition or load sharing score indicates adequate sharing of load through the injured vertebral body itself along with the implant to permit short segment instrumentation and fusion5 ) . short - segment instrumentation ( that is , pedicle screw instrumentation at the fracture level and the levels above and below ) is being selected among warrant surgical interventions . pedicle screw insertion makes it possible to maintain vertebral column stability until the desired alignment is achieved , and simultaneously restores canal dimensions and vertebral body height6 ) . furthermore , it has been assumed to facilitate early painless mobilization by providing substantial stabilization of the fractured vertebra . some authors have hypothesized that bone grafting may be unnecessary in combination with short - segment fixation for the treatment of thoracolumbar burst fractures8 ) . moreover , recent reports have demonstrated the efficacy of vertebral augmentation procedures in terms of preventing implant failure in osteoporotic patients1 ) . in addition , to minimize the negative consequences of traditional open surgery , such as , muscular denervation and atrophy , screw fixation via percuaneous technique has been proposed and applied . we conducted this study to compare and evaluate the efficacies of bone cement augmentation and bone fusion procedure for the treatment of thoracolumbar burst fractures accompanying osteopenia . this retrospective study included 70 patients ( 47 males and 23 females ) with thoracolumbar burst fractures with osteopenia treated at our institute from january 2005 to january 2008 . study inclusion criteria limited enrollment to single level thoracolumbar burst fractures with ; 1 ) a neurologically intact status , despite severe canal encroachment , 2 ) patients with osteopenia ( -2.5 < mean t - score by bone mineral densitometry < -1.0 ) , 3 ) a loss of anterior body height exceeding 40% or more than 30 of sagittal angulation , and 4 ) intact bilateral pedicles , enabling screw insertion at the fractured vertebra . the exclusion criteria were major neurological deficits that required open decompression due to severe canal compromise and an accompanying pedicle fracture preventing screw insertion at the fracture level . the 70 patients were divided into three groups by operation technique : 1 ) group i ( n=26 ) : short segment fixation with posterolateral bone fusion , 2 ) group ii ( n=23 ) : bone cement augmented short segment fixation with posterolateral bone fusion , 3 ) group iii ( n=21 ) : bone cement augmented short segment percutaneous screw fixation without bone fusion ( fig . clinical outcomes were assessed using a visual analogue scale ( vas ) and modified mac nab 's criteria . the effects of the procedures were analyzed preoperatively , 10 days postoperatively , and at final follow - up . radiological findings , including height restoration , kyphotic angle , and other systemic complications , were analyzed . extent of vertebral body collapse was determined using vertebral heights at the point of maximal collapse on lateral radiographs or on midsagittal computed tomography scans . kyphotic angle was measured by drawing a straight line from the superior endplate of the vertebra one level above the fractured body and a straight line from the inferior endplate of the vertebra one level below the fractured body . the three groups were compared with respect to age , gender , mean t - score , kyphotic angle , preoperative degree of pain , and vertebral height . preoperative group differences were evaluated using the student 's t - test for unpaired data , and intra - group changes associated with the procedure were evaluated using the student 's t - test for paired data . group demographics , that is , age , gender , pain , vertebral height , mean t - score , mean follow - up period , and mean kyphotic angle were not significantly different . significant pain relief was achieved in all three groups at last follow - up ( p<0.01 ) . for group i , mean vas scores were ; 7.6 before surgery , 3.0 at 10 days after surgery , and 3.0 at last follow - up . for group ii , mean vas scores were ; 7.5 before surgery , 2.7 at 10 days after surgery , and 2.5 at last follow - up . for group iii , mean vas scores were ; 7.5 before surgery , 2.5 at 10 days after surgery , and 2.6 at last follow - up ( fig . 1 ) . most patients achieved an ' excellent ' or ' good ' result at final follow - up according to modified macnab 's criteria . however , patients that underwent short segment screw fixation with bone fusion ( group i ) showed higher complication rates for screw loosening and implant failure after the procedure than patients in group ii or iii ( p=0.002 ) . the inter - group pairwise comparisons of complications revealed no significant difference between group ii and iii ( p=0.279 ) ( table 2 ) . screw loosening or implant failure was detected in 7 group i patients ( 26.9% ) , 2 group ii patients ( 8.6% ) , and 2 group iii patients ( 9.5% ) during the follow - up period ( fig . i , one male patient developed symptomatic infectious spondylitis that needed revision surgery at six months after screw fixation . no major complications related to bone cement , such as , pulmonary embolism or epidural leakage , were encountered in group ii or iii , although asymptomatic cement leakage occurred into the disc space or posterior spinal canal in some patients . mean kyphotic angle and vertebral height increased significantly at last follow - up in all three groups ( p<0.01 ) , but group i showed more correction loss of kyphotic deformities and vertebral height loss than with group ii or iii ( table 3 ) . minimizing the number of vertebral levels in screw fixation is another important goal of internal fixation . traditional short segment fixation , which is , pedicle screw fixation one level cephalad and one level caudad a fracture , is used to save the motion segments by limiting the number of the fusion segments . despite the theoretical benefits of motion preservation , clinical studies on traditional short segment instrumentation failure to restore anterior column support can lead to secondary kyphosis , depending on the residual load transfer capacity of the fractured vertebral body . however , the trend toward preservation of motion segments using short segment instrumentation has continued to gain popularity , especially when anterior column support is not severely compromised5 ) . in the present study , the radiographic and clinical outcomes of neurologically intact patients with a thoracolumbar burst fracture that underwent short segment fixation at the level of the fracture with or without posterolateral fusion and a vertebral augmentation procedure were analyzed . although kyphotic angle , vertebral height restoration , and clinical outcome were not significantly different in the three groups , our results show that bone cement augmentation seems to be essential in terms of reducing screw loosening and implant failure rates . the pedicle screw - based instrumentation system has been used widely for the treatment of thoracolumbar fractures , and posterior fixation with pedicle instrumentation not only allows satisfactory fracture reduction but also provides immediate mechanical stability and alignment while preventing additional damage to non - injured segments . with regard to posterior fixation , spinal fusion however , short segment fixation with bone has also been associated with considerable rates of implant failure and correction loss2,4 ) . some authors have recently reported the results for posterior screw fixation without bone fusion for the treatment of thoracolumbar burst fractures . sanderson et al.6 ) , in a retrospective study , examined 24 patients who had undergone short - segment fixation without fusion , and concluded that routine posterior or posterolateral fusion is unnecessary . in 2006 , wang et al.8 ) , also reported satisfactory results for short - segment fixation without fusion in surgically - treated thoracolumbar burst fractures , and found that low back outcome scores were no different for patients treatment with or without bone fusion . however , in the osteoporotic or osteopenic spine , the screw anchoring effect is reduced and the probability of hardware failure is high , and thus , the possibility of non - union is increased7 ) . therefore , screw loosening or vertebral collapse may occur more frequently after screw fixation without bone fusion in osteoporotic or osteopenic spines . however , insertion of pedicle screws at the fracture level results in a segmental construct that improves biomechanical stability by protecting the fractured body and by supporting the anterior column indirectly3 ) . in addition , the insertion of bone cement to augment pedicle screws at the fracture level probably results in a segmental construct with improved biomechanical stability by providing protection to the fractured vertebral body and indirectly supporting the anterior column3 ) . furthermore , bone cement augmentation at fractured level itself and adjacent vertebrae can significantly reduce pedicle screw bending and increase initial stiffness in the flexion - extension plane . wittenberg et al.9 ) reported that pmma can increase pull - out strength from 96% to 262% and transverse bending stiffness by up to 153%9 ) . in the present study mean kyphotic angle and vertebral height increased significantly at last follow - up in all three groups . however , improved vertebral height and kyphotic angle were maintained during the follow - up and lower complication rates were observed in bone cement augmented screw fixation groups ( group ii and iii ) . as a result , bone cement augmented screw fixation procedure including fractured level was helpful for prevent screw loosening and implant failure . moreover , due to the advance in minimally invasive instrumentation , bone cement augmented , percutaneous screw fixation was a safe and effective management to reduce screw loosening implant failure for the thoracolumbar burst fractures without neurologic deficits . all surgical procedures in this study were performed by a single surgeon to eliminate the effects of different surgeons on outcome variables . however , larger - scale , multicenter studies involving more surgeons and fracture types are required to validate our results . bone cement augmentation procedure is an effective and reliable operative technique for reducing screw loosening and implant failure after short segment fixation for thoracolumbar burst fractures accompanying osteopenia .