***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: Summary The FREEDOM study and its Extension provide long-term information about the effects of denosumab for the treatment of postmenopausal osteoporosis . Treatment for up to 8 years was associated with persistent reduction of bone turnover , continued increases in bone mineral density , low fracture incidence , and a favorable benefit/risk profile . Introduction This study aims to report the results through year 5 of the FREEDOM Extension study , representing up to 8 years of continued denosumab treatment in postmenopausal women with osteoporosis . Methods Women who completed the 3-year FREEDOM study were eligible to enter the 7-year open-label  FREEDOM Extension in which all participants are scheduled to receive denosumab , since placebo assignment was discontinued for ethical reasons . A total of 4550 women enrolled in the Extension ( 2343 long-term ; 2207 cross-over ) . In this analysis , women in the long-term and cross-over groups received denosumab for up to 8 and 5 years , respectively . Results Throughout the Extension , sustained reduction of bone turnover markers ( BTMs ) was observed in both groups . In the long-term group , mean bone mineral density ( BMD ) continued to increase significantly at each time point measured , for cumulative 8-year gains of 18.4 and 8.3 % at the lumbar spine and total hip , respectively . In the cross-over group , mean BMD increased significantly from the Extension baseline for 5-year cumulative gains of 13.1 and 6.2 % at the lumbar spine and total hip , respectively . The yearly incidence of new vertebral and nonvertebral fractures remained low in both groups . The incidence of adverse and serious adverse events did not increase over time . Through Extension year 5 , eight events of osteonecrosis of the jaw and two events of atypical femoral fracture were confirmed . Conclusions Denosumab treatment for up to 8 years was associated with persistent reductions of BTMs , continued BMD gains , low fracture incidence , and a consistent safety profile Study Design . Retrospective case-control study . Objective . To determine the association of Hounsfield unit ( HU ) measurements with adjacent segment fractures after spinal fusion . Summary of Background Data . Adjacent segment fracture is a potentially devastating complication after spinal fusion surgery in osteoporotic patient . Recently , a technique for assessing bone mineral density using HU measurements from computed tomography was described and correlated with both dual-energy x-ray absorptiometry – assessed bone mineral density and compressive strength in an osseous model . Methods . Patients with adjacent segment fractures after spinal fusion were identified from a prospect ively collected patient data base and matched 1:1 with nonfracture controls on the basis of age , sex , and fusion construct . Minimum follow-up was 6 months . Patients with metabolic bone disease other than osteoporosis or those taking medications known to negatively alter bone strength were excluded .  HU assessment was done according to the previously published protocol using the preoperative computed tomography . Results . Twenty patients had complete imaging data and could be matched to nonfracture  controls  . The groups were well matched with respect to age , sex , body mass index , and number of levels fused . Following the index surgical procedure , the fracture group had more positive sagittal balance than the control group ( 10.7 cm vs. 9.1 cm ) . Analysis of HU values at the fracture level showed a significantly lower value in the fracture group than in the controls ( 145.6 vs. 199.4 , P = 0.006 ) . Similarly , global assessment of HU across the thoracic and lumbar spines was significantly lower in the fracture group ( 139.9 vs. 170.1 , P = 0.032 ) . Conclusion . HU was significantly lower both locally and globally in the fracture cohort . Because computed tomographic scans are frequently part of preoperative planning for spinal fusion , this information should be incorporated in preoperative planning . Studies to prospect ively vali date HU as a predictor of adjacent segment fracture risk and to assess the effect of increasing HU preoperatively with medications for osteoporosis are needed . Level of Evidence : Osteoporosis is a major global health problem , with over 10 million people currently diagnosed with the disease . Although 80 % of osteoporotic patients are women , a considerable number of men are also affected . Also , due to increasing life expectancy , the number of elderly patients with osteoporosis affected by degenerative and traumatic spinal diseases will increase further . Osteoporosis reduces bone quality through negative bone remodelling . Low bone quality can reduce the pull-out strength of pedicle screw , and negative bone remodelling can cause delayed bone fusion . However , pedicle screw instrumentation of the osteoporotic spine carries an increased risk of screw loosening , pull-out , and fixation failure . Our preliminary study aims to investigate the efficiency of exp and able pedicle screws ( OsseoScrew-Spinal Fixation System , Alphatec Spine Inc. , Carlsbad , CA ) in osteoporotic spinal patients . All osteoporotic patients with degenerative and traumatic spinal diseases admitted in our department underwent a pre-operative spinal x-Ray and MRI or CT . Pre-operative clinical assesment of patients was based on the visual analog scale ( VAS ) and Owestry Disability ( ODI ) question naire-a disease-specific outcome measure . Ten osteoporotic patients were treated with exp and able pedicle screws ( OsseoScrew ) . Post-operative clinical assessment of patients was based on the VAS and ODI question naire at 3 months and 1 year of follow-up . Post-operative radiologic follow-up was performed after 3 days ( CT , x-ray ) ; 3 months ( x-ray ) ; 6 months ( spinal CT ) ; and 1 year ( spinal CT ) . Exp and able pedicle screws improved pull-out strength as compared to st and ard pedicle screws in osteoporotic patients with degenerative and traumatic spinal diseases Purpose The LLIF procedure is a useful st and -alone and adjunct surgical approach for many spinal conditions . One complication of LLIF is subsidence of the interbody graft into the vertebral bodies , result ing in severe pain , impaired arthrodesis and potentially fracture of the body . Low bone density , as measured by T score on DEXA scanning , has also been postulated to increase the risk of subsidence . Methods A retrospective review of prospect ively collected data was performed on all patients who underwent LLIF at this institution consisting of 712 levels in 335 patients . Patients with subsidence following LLIF were recorded . We utilized the  T score obtained from the femoral neck DEXA scans , which is used to determine overall fracture risk . The T score of patients with subsidence was compared to those without subsidence . Results 20 of 57 ( 35 % ) patients without subsidence had a DEXA T score between −1.0 and −2.4 consistent osteopenia , one patient ( 1.8 % ) exhibited a T score less than −2.5 , consistent with osteoporosis . 13 patients of 23 ( 57 % ) with subsidence exhibited a T score between −1.0 and −2.4 , consistent with osteopenia , five ( 22 % ) exhibited a T score of −2.5 or less , consistent with osteoporosis . The mean DEXA T score in patients with subsidence was −1.65 ( SD 1.04 ) compared to −0.45 ( SD 0.97 ) in patients without subsidence ( p < 0.01 ) . The area under the receiver operating characteristic curve for patients with a T score of −1.0 or less was 80.1 % . Conclusions Patients with DEXA T scores less than −1.0 who undergo st and -alone LLIF are at a much higher risk of developing graft subsidence . Further , they are at an increased risk of requiring additional surgery . In patients with poor bone quality , consideration could be made to supplement the LLIF cage with posterior instrumentation Study Design . Prospect i ve trial . Objective . To examine the clinical efficacy of teriparatide for bone union after instrumented lumbar posterolateral fusion using local bone grafting in women with postmenopausal osteoporosis . Summary of Background Data . Intermittent parathyroid hormone ( PTH ) treatment increases bone mass and reduces the risk for osteoporotic vertebral fractures . Recombinant human PTH ( 1–34 ) has already been approved as a treatment for severe osteoporosis . Pre clinical data support the efficacy of PTH for lumbar spinal fusion . However , clinical results of PTH for spinal fusion have not yet been reported . Methods . Fifty-seven women with osteoporosis diagnosed with degenerative spondylolisthesis were divided into 2 treatment groups , a teriparatide group ( n = 29 ; daily subcutaneous injection of 20 & mgr;g of teriparatide ) and a bisphosphonate group ( n = 28 ; weekly oral administration of 17.5 mg of risedronate ) . All patients underwent decompression and 1- or 2-level instrumented posterolateral fusion with a local bone graft .  Fusion rate , duration of bone union , and pain scores were evaluated 1 year after surgery . Results . Pain scores improved after surgery ; however , no significant difference was noted between the groups after surgery . The rate of bone union was 82 % in the teriparatide group and 68 % in the bisphosphonate group . Average duration of bone union was 8 months in the teriparatide group and 10 months in the bisphosphonate group . The rate of bone union and average of duration of bone union in the teriparatide group patients were significantly superior to those in the bisphosphonate group . Conclusion . Daily subcutaneous injection of teriparatide for bone union using local bone grafting after instrumented lumbar posterolateral fusion in women with postmenopausal osteoporosis was more effective than oral administration of bisphosphonate Type of study A 2 to 4-year clinical and radiologic prospect i ve study was conducted for 39 patients over the age of 65 treated by lumbar arthrodesis .  Objectives Evaluate the quality of lumbar arthrodesis results in elderly patients , in which the bone osteoporosis ( poor quality of the spine 's anatomic components ) and general factors ( frequent comorbidity ) are likely to make this surgery difficult if not dangerous and evaluate a dedicated instrumentation for osteoporotic bone . Material s and Methods Thirty-nine patients over 65 years of age ( average 73 y ) underwent arthrodesis surgery in 2001 and 2002 and were followed for at least 2 years . The instrumentation used ( Equation , Medtronic , Memphis , USA ) was selected for its mechanical properties adapted for bone of poor mechanical quality . The clinical analysis was based on Oswestry , Visual Analog Scale , and Japanese Orthopaedic Association scores . Radiologic results were evaluated on st and ard anteroposterior , lateral , and 3/4 radiographs , and computed tomography scans if necessary . Results All the patients were followed for 2 to 4 years . Clinical analysis confirmed a very satisfactory progression of the clinical parameters such as lumbar and radicular pain , and the results were maintained between the first and second years and at last follow-up . No serious general complication or need for reoperation was seen in this series . On x-rays , 35 grafts appear to have fused . The anchors did not come out nor did the instrumentation come apart . On the other h and , 2-year radiographs revealed that 2 screws and 2 rods had failed , but this did not affect correction in the 4 completely asymptomatic patients . These 4 cases are considered stable at last follow-up . Conclusions Arthrodesis for elderly patients will undoubtedly increase in the coming years . The conditions for this surgery are different than those for younger patients and it is desirable to try to provide reliable surgical techniques and solutions regarding options for instrumentation and overall perioperative care for these fragile patients . Dedicated instrumentation for osteoporotic bone seems to allow good clinical outcomes BACKGROUND CONTEXT Pedicle screw fixation in osteoporotic bone and in revision of previous pedicle screw fixation cases presents a significant challenge to spine surgeons . Biomechanical tests have shown that a pedicle screw that exp and s within the vertebrae body can substantially improve fixation in the presence of compromised bone . PURPOSE To review the clinical and radiographic results with the use of exp and able pedicle screws . STUDY DESIGN One hundred forty-five patients received one or more exp and able pedicle screws from the Omega21 spinal fixation system ( EBI , L.P. , Parsippany , NJ ) to obtain thorocolumbar or lumbosacral stabilization . PATIENT SAMPLE The indications for use of the exp and able screws were osteoporosis ( 21 cases ) , reoperation of previous pedicle instrumentation ( 27 cases ) , intraoperative screw relocation ( 17 cases ) , construct reinforcement ( 23 cases ) , and sacral anchoring to avoid the necessity of anterior penetration of the sacral cortex ( 57 cases ) . OUTCOME MEASURES The presence of radiographic fusion and complications arising from the instrumentation were review ed at a mean follow-up period of 35 months ( range , 24 - 72 months ) . METHODS A retrospective clinical and radiographic review was performed . Fusion was evaluated based on anterior-posterior and lateral radiographs as well as dynamic radiographs in flexion and extension . RESULTS Radiographic evidence of fusion was obtained in 125 of the 145 cases ( 86 % ) . Eighty-six 
    Output:
    
The strongest evidence was for perioperative teriparatide .
Conclusion : There are 15 articles evaluating osteoporosis in patients undergoing lumbar fusion and the highest level of evidence is for perioperative use of teriparatide