***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: STUDY DESIGN A prospect i ve clinical study . OBJECTIVE To evaluate whether a percutaneous dorsal instrumentation of thoracolumbar fractures  prevents irreversible damage to the spinal muscles . METHODS A total of 57 patients with thoracolumbar fractures ( Th12-L4 ) were divided into two groups , comparable in terms of gender , fracture level , classification and surgical concept . In the first , 24/57 patients were treated using an open procedure ( OP-G ) ; in the second , 33/57 were treated via percutaneous dorsal instrumentation ( PER-G ) . Fracture localisation and classification , accuracy of pedicle screw placement , perioperative blood loss , OR- and image converter time as well as muscle damage ( needle-EMG )  were evaluated . RESULTS OR- and image converter time as well as the accuracy of pedicle screw placement were not statistically different between groups . The difference in perioperative blood loss [ 43 ( 10 - 90 ) ml ( PER-G ) vs [ 870 ( 570 - 1,200 ml ( OP-G ) ] was statistically significant ( P < 0.005 ) . Needle EMG revealed no muscle damage , and the physiological activity and muscle potentials were normal ( PER-G ) . In the OP-G , polyphasic EMG signals were most common ( 80 % ) , a sign of the drop-out of numerous motor units . CONCLUSIONS The open procedure caused permanent and significant damage to the strongest extensors of the autochthonus back musculature , the m. multifidus , which results from multisegment combined damage to the r. posterior nervi spinalis and muscle fibres . In contrast , percutaneous placement of an internal fixative reduces perioperative access morbidity causing little iatrogenic damage to back muscles and only a minor perioperative blood loss OBJECTIVE To compare the clinical results between computer assisted minimally invasive spine surgery ( CAMISS ) and traditional open fixation surgery which used in thoracolumbar fractures . METHODS A prospect i ve r and omized controlled trial of patients who had undergone surgery for thoracolumbar fracture from January 2006 to March 2011 was performed . The patients were r and omly divided into CAMISS group and traditional open treatment group ( control group ) by r and om number table . Clinical results were assessed by comparing the following parameters between patients who had undergone CAMISS or traditional open surgery :  operative time , estimated blood loss , visual analogue scale ( VAS ) of the low back pain , the accuracy of pedicle screw , the status and the correction of kyphosis . RESULTS Forty-seven patients underwent CAMISS , and fifty patients underwent traditional open surgery .  The follow-up periods were 3 - 50 months ( mean 12 months ) . According to the preoperative data , the two groups did not differ with respect to age , gender , marriage , occupation , mechanism of injury , classification of fracture , preoperative VAS scores of the low back pain , preoperative functional spine unit ( FSU ) Cobb 's angle and preoperative local angle of the fracture vertebral body ( P > 0.05 ) . Compare to the control group , the patients who got CAMISS had more accuracy of pedicle screw , less blood loss , short immobilized time , lower postoperative fever , and better VAS score of the low back pain ( t = 2.162 - 8.736 , P < 0.05 ) . The improvement of FSU Cobb 's angle and local angle of the fracture vertebral body were better at control group after operation ( 13.8 ° ± 6.8 ° vs. 10.9 ° ± 5.5 ° , 11.0 ° ± 6.0 ° vs. 7.7 ° ± 4.8 ° , t = 2.108 and 2.610 , P < 0.05 ) . But there was no significant difference of the FSU Cobb 's angle , or local angle of the fracture vertebral body between the two groups at post-operation and follow-up ( P > 0.05 ) . CONCLUSIONS CAMISS has the characteristics of fewer traumas , less bleeding , faster recovery , high accuracy of pedicle screws . It has comparable vertebral deformity correction and fixation result of the traditional open operation OBJECTIVE To investigate the methods for , and clinical outcome of , the operative treatment of thoracolumbar fractures through an approach via the paravertebral muscle ( PVM ) . METHODS From June 2005 to August 2006 , 62 patients , comprising 48 men and 14 women with an average age of 45.2 years ( range , 21 - 58 ) with thoracolumbar fractures without neurological involvement underwent surgical treatment .  Twenty-one fractures were located at T12 , 24 at L1 and 17 at L2 . The study comprised 15 compression and 47 burst fractures with an intact posterior column . Thirty-four cases were selected r and omly to undergo surgery through the above approach , while the other 28 cases underwent the traditional procedure . After making a posterior midline incision , which not only facilitates insertion of pedicle screws and fusion of the graft bone at facet joints , but spares the attachment of PVM , the interval between the longissimus and multifidus muscles was undermined . Drainage was not routinely needed and the patients became ambulant with a brace earlier post-operatively . RESULTS The new approach had statistically significant advantages ( P < 0.005 ) over the traditional one in regard to blood loss , drainage , duration of recumbency and visual analogue scale ( VAS ) , although the time required was almost the same for the two procedures . Till August 2007 , 56 patients were successfully followed up for 12 to 26 months ( mean , 18.6 ) and bone fusion was identified in all cases . Neither reduction loss nor loosening or breakage of the fixation occurred . CONCLUSION The technique of operating through an approach between the PVM is recommended for thoracolumbar fractures because it is much less invasive , can reduce blood loss and accelerates rehabilitation OBJECTIVE  Anterior lumbar interbody fusion ( ALIF )  is a common procedure used to treat various lumbar degenerative pathologies . The purpose of this study is to describe 30-day postoperative outcomes following ALIF on a national scale . METHODS The American College of Surgeons National Surgery Quality Improvement Program ( ACS NSQIP ) was search ed for ALIF patients between 2005 and 2011 . The top preoperative diagnoses were determined using ICD-9 codes . All available 30-day complications were grouped as overall composite morbidity and were compared between preoperative diagnosis groups by univariable and multivariable analyses . RESULTS There were a total of 1352 ALIF patients . Overall , 6.73 % of patients experienced a postoperative complication . Unplanned reoperations ( 2.48 % ) , urinary tract infection ( 1.55 % ) , superficial surgical site infection ( 1.41 % ) , and sepsis ( 1.11 % ) were the most common morbidity events . The morbidity rates for each sub-group were : intervertebral disc degeneration ( 4.41 % ) , spondylosis ( 6.72 % ) , lumbosacral spinal stenosis(8.21 % ) , and spondylolisthesis ( 8.41 % ) . After extensive adjustment for patient characteristics and preoperative morbidities , multivariable analysis revealed spondylolisthesis ( OR=3.29 ; 95 % CI:1.04 - 10.46 ) and spinal stenosis ( OR=3.76 ; 95 % CI:1.33 - 10.63 ) to be associated with significantly higher overall morbidity odds when compared with lumbar disc degeneration . Lumbosacral spondylosis was associated with similar outcomes as degenerative disc disease ( OR = 1.70 ; 95 % CI:0.48 - 6.06 ) . CONCLUSIONS Diverse postoperative complications need to be managed following ALIF . Patients with spondylolisthesis and spinal stenosis may carry increased 30-day postoperative morbidity profiles in ALIF when compared to those with degenerative disc disease . Prospect i ve studies are needed to better delineate the outcomes of ALIF procedures , particularly in the spondylolisthesis and spinal stenosis patient population PURPOSE OF THE STUDY A prospect i ve cohort study evaluates the functional and radiological outcome of thoracolumbar spine fractures treated either with open or percutaneous dorsal instrumentation .  In recent years , several studies advocate percutaneous stabilization of spinal fractures in patients without neurological deficits . However , it is still debated whether percutaneous stabilization is superior to open dorsal instrumentation in spinal trauma . MATERIAL AND METHODS This study was performed between 2010 and 2012 at a Level 1 trauma center . Patients treated either with an open or a percutaneous dorsal instrumentation for traumatic fractures of the thoracolumbar spine ( T11 to L2 ) were included .  Fracture morphology , screw positioning and clinical parameters were analyzed . St and ardized question naires ( VAS-spine-score ; Oswestry-disability-score ; SF-36 ) and follow up radiographs were performed . RESULTS Overall 72 patients ( 29 percutaneous ; 43 open ) could be included . The surgical and the early postsurgical course were similar between both groups . Furthermore the operative approach had no influence on the functional and radiological outcome one year after surgery , but the question naires showed moderate impairments within both groups . Also both groups showed a significant loss of reduction after the first postoperative month ( p < 0.01 ) . Within the open group a significantly higher amount of fracture reduction ( p < 0.01 ) and a significantly reduced intraoperative radiation exposure was seen ( open 105.9 sec. ; percutaneous 143.1 sec ; p < 0.05 ) ; whereas the percutaneous approach was associated with significantly reduced intraoperative blood loss ( open 2.2 g/dl ; percutaneous 1.2 g/dl ; p < 0.001 ) . CONCLUSION The functional and the radiological outcome of both groups was comparable one year after trauma . Minor advantages of the percutaneous system was less blood loss , whereas the open approach was associated with a significantly higher amount of initial reduction and significantly less intraoperative radiation exposure . Independent from the type of posterior fixation loss of reduction was already significant in the early postoperative course Purpose To evaluate the outcome of pure percutaneous fixation of unstable single level fractures at the thoraco-lumbar junction ( A1 to B2 Magerl/AO Spine ) . Method Neurological intact patients were included in a 2-year prospect i ve study ( follow-up 36 months ) . Two groups were considered : the group in which additional short bilateral screws in the fractured vertebra were placed was called lordorizing screw group ( LSG ) , the other was called non lordorizing screw group ( nLSG ) . Clinical outcome was evaluated using the SF-36 , the Oswestry disability index and the recovery time needed to go back work . The following radiological parameters were also evaluated on the follow-up exams : the Mid-Sagittal Index , the Cobb ’s angle and the Sagittal Index . Results In the LSG , the correction values of MSI , Cobb ’s angle and SI were statistically significantly higher than in nLSG . Conclusion When feasible we recommend a pure percutaneous short segment pedicle screw fixation adding a lordorizing screw OBJECTIVE : This prospect i ve r and omized controlled study compared the efficacy and safety of two paraspinal muscle-sparing surgical approaches for the management of neurologically intact patients with thoracolumbar burst fractures and posterior ligamentous complex injuries . METHODS : Patients were r and omized to undergo either percutaneous ( n = 31 ) or paraspinal ( n = 30 ) fluoroscopically-guided pedicle screw — rod fixation , and were followed for ≥ 3 years . Preoperative postural reduction was attempted in all patients . RESULTS : The percutaneous approach was associated with significantly less intraoperative blood loss and shorter duration of surgery and hospitalization , as well as less pain and better functional recovery at 3 months after surgery compared with the paraspinal approach . Paraspinal surgery result ed in significantly better correction of kyphosis and restoration of vertebral height compared with percutaneous surgery . There were no differences in long-term clinical outcomes between the two groups . CONCLUSIONS : The minimally invasive percutaneous approach appears to be better in cases of successful postural reduction . The paraspinal approach results in better surgical correction and is , therefore , recommended for patients without successful postural reduction OBJECT Flexion-distraction injuries occur due to distractive forces causing disruption of the posterior and middle spinal columns . These fractures classically consist of a fracture line through the posterior bony elements ; involvement of the posterior ligamentous complex is , however , common . Surgical treatment is often required for these unstable injuries to avoid neurological deterioration and posttraumatic kyphosis , and the surgery traditionally consists of an open posterior approach with instrumented fusion . Percutaneous pedicle screw fixation for these injuries , with the goal of minimal tissue disruption and preservation of normal anatomy while achieving adequate stabilization , has recently been reported in the literature , but to date , a direct comparative study comparing open and percutaneous fixation has not been reported . The authors report their experience treating these fractures with both techniques and review the available literature . METHODS Patients with flexion-distraction injury who were treated between May 20 
    Output:
    
Percutaneous approach was associated with better ODI score , less Cobb angle correction , less Cobb angle correction loss , less postoperative VBA correction , and lower infection rate compared with open approach .
Percutaneous approach was also associated with shorter operative duration , longer intraoperative fluoroscopy , less postoperative VAS , and postoperative VBH% in comparison with traditional open approach .
No significant difference was found in Cobb angle correction , postoperative VBA , VBA correction loss , Postoperative VBH% , VBH correction loss , and pedicle screw misplacement between percutaneous approach and open approach .
There was no significant difference in operative duration , intraoperative fluoroscopy , postoperative VAS , and postoperative VBH% between percutaneous approach and paraspianl approach .
Conclusions The functional and the radiological outcome of percutaneous approach would be better than open approach in the long term .
Although trans-muscular spatium approach belonged to open fixation methods , it was strictly defined as less invasive approach , which provided less injury to the paraspinal muscles and better reposition effect