***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 clinical prospect i ve observational cohort study of 15 patients undergoing cervical intervertebral disc replacement .  Objective . To assess the safety , clinical stability , and capacity of a newly design ed cervical intervertebral disc replacement for preserving motion in the cervical spine of patients with degenerative disc disease . Summary of Background Data . Anterior cervical discectomy and interbody fusion results in loss of motion segments and there is evidence of accelerated degenerative changes occurring at adjacent levels . Intervertebral disc replacement may be a valid alternative to fusion . There is a need for cervical disc replacement to be evaluated in prospect i ve studies before it can be adopted as an acceptable surgical technique . Methods . The study enrolled 15 patients with cervical radiculopathy or myelopathy and radiologically confirmed cervical disc herniation or posterior vertebral body osteophytes . Eligibility for the study required that patients have either a previous adjacent-level surgical or congenital spinal fusion or radiologic evidence of adjacent-level degenerative disc disease . After decompressive surgery via an anterior approach , all 15 patients received the  artificial joint . Follow-up visits were at set intervals and included clinical examination , radiologic assessment , and evaluation by patient-completed question naires . Results . In all cases , the artificial joint maintained motion at the operative levels while reestablishing intervertebral height . The procedure was considered safe for experienced spine surgeons to perform , and the device was stable , with no dislocation of components or backing out of screws . Two screws broke , but without any consequence . Improvements in assessment scores were noted . Conclusions . Cervical intervertebral motion can be maintained with the new device , which is clinical ly stable . Meticulous attention must be paid to the surgical technique to maximize the chances of a good result . The pilot study was successful , although it has yet to be determined what conditions will benefit most from this technology BACKGROUND CONTEXT Cervical total disc replacement ( TDR ) is intended to address radicular pain and preserve functional motion between two vertebral bodies in patients with symptomatic cervical disc disease ( SCDD ) . PURPOSE The purpose of this trial is to compare the safety and efficacy of cervical TDR , ProDisc-C ( Synthes Spine Company , L.P. , West Chester , PA ) , to anterior cervical discectomy and fusion ( ACDF ) surgery for the treatment of one-level SCDD between C3 and C7 . STUDY DESIGN / SETTING The study was conducted at 13 sites . A noninferiority design with a 1:1 r and omization was used . PATIENT SAMPLE Two hundred nine patients were r and omized and treated ( 106 ACDF ; 103 ProDisc-C ) . OUTCOME MEASURES Visual analog scale ( VAS ) pain and intensity ( neck and arm ) , VAS satisfaction , neck disability index ( NDI ) , neurological exam , device success , adverse event occurrence , and short form-36 ( SF-36 ) st and ardized question naires . METHODS A prospect i ve , r and omized , controlled clinical trial was performed . Patients were enrolled and treated in accordance with the US Food and Drug Administration ( FDA ) -approved protocol . Patients were assessed pre- and postoperatively at six weeks , 3 , 6 , 12 , 18 , and 24 months . RESULTS Demographics were similar between the two patient groups ( ProDisc-C : 42.1+/-8.4 years , 44.7 % males ; Fusion : 43.5 + /- 7.1 years , 46.2 % males ) . The most commonly treated level was C5-C6 ( ProDisc-C : 56.3 % ; Fusion=57.5 % ) . NDI and SF-36 scores were significantly less compared with presurgery scores at all follow-up visits for both the treatment groups ( p<.0001 ) . VAS neck pain intensity and frequency as well as VAS arm pain intensity and frequency were statistically lower at all follow-up timepoints compared with preoperative levels ( p<.0001 ) but were not different between treatments . Neurologic success ( improvement or maintenance ) was achieved at 24 months in 90.9 % of ProDisc-C and 88.0 % of Fusion patients ( p=.638 ) . Results show that at 24 months postoperatively , 84.4 % of ProDisc-C patients achieved a more than or equal to 4 degrees of motion or maintained motion relative to preoperative baseline at the operated level . There was a statistically significant difference in the number of secondary surgeries with 8.5 % of Fusion patients needing a re-operation , revision , or supplemental fixation within the 24 month postoperative period compared with 1.8 % of ProDisc-C patients ( p=.033 ) . At 24 months , there was a statistically significant difference in medication usage with 89.9 % of ProDisc-C patients not on strong narcotics or muscle relaxants , compared with 81.5 % of Fusion patients . CONCLUSIONS The results of this clinical trial demonstrate that ProDisc-C is a safe and effective surgical treatment for patients with disabling cervical radiculopathy because of single-level disease . By all primary and secondary measures evaluated , clinical outcomes after ProDisc-C implantation were either equivalent or superior to those same clinical outcomes after Fusion OBJECT The authors report the results of a prospect i ve r and omized multicenter study in which the results of cervical disc arthroplasty were compared with anterior cervical discectomy and fusion ( ACDF ) in patients treated for symptomatic single-level cervical degenerative disc disease ( DDD ) . METHODS Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and r and omly assigned to one of two treatment groups : 276 patients in the investigational group underwent anterior cervical discectomy and decompression and arthroplasty with the PRESTIGE ST Cervical Disc System ( Medtronic Sofamor Danek ) ;  265 patients in the control group underwent decompressive ACDF . Eighty percent of the arthroplasty-treated patients ( 223 of 276 ) and 75 % of the control patients ( 198 of 265 ) completed clinical and radiographic follow-up examinations at routine intervals for 2 years after surgery . Analysis of all currently available postoperative 12- and 24-month data indicated a two-point greater improvement in the neck disability index score in the investigational group than the control group . The arthroplasty group also had a statistically significant higher rate of neurological success ( p = 0.005 ) as well as a lower rate of secondary revision surgeries ( p = 0.0277 ) and supplemental fixation ( p = 0.0031 ) . The mean improvement in the 36-Item Short Form Health Survey Physical Component Summary scores was greater in the investigational group at 12 and 24 months , as was relief of neck pain . The patients in the investigational group returned to work 16 days sooner than those in the control group , and the rate of adjacent-segment reoperation was significantly lower in the investigational group as well ( p = 0.0492 , log-rank test ) . The cervical disc implant maintained segmental sagittal angular motion averaging more than 7 degrees . In the investigational group , there were no cases of implant failure or migration . CONCLUSIONS The PRESTIGE ST Cervical Disc System maintained physiological segmental motion at 24 months after implantation and was associated with improved neurological success , improved clinical outcomes , and a reduced rate of secondary surgeries compared with ACDF BACKGROUND Ten-year follow-up data from the US Food and Drug Administration investigational device exemption trial comparing BRYAN ® Cervical Disc ( Medtronic , Dublin , Irel and ) arthroplasty to anterior cervical discectomy and fusion ( ACDF ) demonstrated that disc arthroplasty maintained range of motion and improvements in overall success and neck disability . OBJECTIVE To compare the 10-yr rates of symptomatic adjacent level disease requiring surgery ( SALDRS ) . METHODS Prospect i ve r and omized trial data were analyzed comparing BRYAN ® Cervical Disc arthroplasty to ACDF  for single-level cervical disc disease with concordant radiculopathy or myelopathy with clinicoradiographic analysis at 10 yr . Secondarily , 84-mo data were pooled with PRESTIGE ® Cervical Disc arthroplasty ( Medtronic ) study data to provide overall rates of SALDRS . RESULTS Significantly greater overall success was maintained at every postoperative interval with an overall success rate of 81.3 % with BRYAN ® disc and 66.3 % with ACDF ( P = .005 ) without loss of motion preservation ( 8.69 ° vs 0.60 ° ) . Reoperation at adjacent levels up to the 120-mo visit was 9.7 % in the arthroplasty group and 15.8 % in the ACDF group ( P = .146 ) . The combined data from BRYAN ® and Prestige ST demonstrate that BRYAN ® and Prestige disc groups had a lower rate of second surgeries at the adjacent levels , up to the 84-mo visit , compared to the combined ACDF groups ( 6.9 % vs 11.7 % ; P = .023 ) . CONCLUSION Compared with ACDF , fewer patients with the BRYAN ® disc required surgery for symptomatic adjacent level degeneration , but this did not achieve statistical significance . Analysis of combined study data using Bryan and Prestige discs shows significant differences in SADLRS as early as 7 yr Study Design . Prospect i ve , multicenter , r and omized , and controlled Investigational Device Exemption clinical trial . Objective . To compare the clinical safety and effectiveness of the selectively constrained SECURE-C ( Globus Medical , Audubon , PA ) Cervical Artificial Disc to anterior cervical discectomy and fusion ( ACDF ) . Summary of Background Data . Cervical total disc replacement has been developed as an alternative to ACDF by allowing segmental motion . Current cervical total disc replacement design s incorporate constrained and unconstrained metal-on-metal or metal-on-polymer articulating design s with various means of fixation . Methods . A total of 380 patients from 18 investigational sites were prospect ively enrolled in the study . Patients were r and omized , treated surgically , and evaluated postoperatively at 6 weeks , 3 months , 6 months , 12 months , and 24 months . Clinical outcomes include overall success , visual analogue scale pain ( right arm , left arm , and neck ) , neck disability index , neurological status , Short Form 36 ( SF-36 ) Health Status Survey question naires , range of motion , and adverse events . Bayesian statistical methods were used to analyze the outcomes . Results . Overall success results demonstrated statistical superiority of the r and omized SECURE-C group compared with the r and omized ACDF group at 24 months , with a posterior probability of 100 % using the protocol -specified criteria and 98.1 % using Food and Drug Administration-defined criteria . At 24 months postoperatively , SECURE-C demonstrated clinical ly significant improvement in pain and function in terms of neck disability index , visual analogue scale , and 36-Item Short Form Health Survey . At 24 months , the percentage of patients experiencing secondary surgical interventions at the index level was statistically lower for the SECURE-C group ( 2.5 % ) than the ACDF group ( 9.7 % ) . At 24 months , 84.6 % of as-treated SECURE-C patients were range-of-motion successes . Satisfaction was high among SECURE-C patients . Conclusion . The selectively constrained SECURE-C Cervical Artificial Disc is as safe and effective as the st and ard of care , an anterior cervical discectomy and fusion . SECURE-C is statistically superior in terms of overall success , index-level subsequent surgical procedures , and patient satisfaction , making it an attractive surgical option for patients with symptomatic cervical disc disease . Level of Evidence : BACKGROUND In patients with single-level cervical degenerative disc disease , total disc arthroplasty can relieve radicular pain and preserve functional motion between two vertebrae . We compared the efficacy and safety of cervical total disc arthroplasty with that of anterior cervical discectomy and fusion ( ACDF ) for the treatment of single-level cervical degenerative disc disease between C3-C4 and C6-C7 . METHODS Two hundred and nine patients at thirteen sites were r and omly treated with either total disc arthroplasty with ProDisc-C ( n = 103 ) or with ACDF ( n = 106 ) . Patients were assessed preoperatively ; at six weeks and three , six , twelve , eighteen , and twenty-four months postoperatively ; and then annually until seven years postoperatively . Outcome measures included the Neck Disability Index ( NDI ) , the Short Form-36 ( SF-36 ) , postoperative neurologic parameters , secondary surgical procedures , adverse events , neck and arm pain , and satisfaction scores . RESULTS At seven years , the overall follow-up rate was 92 % ( 152 of 165 ) . There were no significant differences in demographic factors , follow-up rate , or patient-reported outcomes between groups . Both procedures were effective in reducing neck and arm pain and improving and maintaining function and health-related quality of life . Neurologic status was improved or maintained in 88 % and 89 % of the patients in the ProDisc-C and ACDF groups , respectively . After seven years of follow-up , thirty secondary surgical procedures had been performed in nineteen ( 18 % ) of 106 patients in the ACDF group compared with seven secondary surgical procedures in seven ( 7 % ) of 103 patients in the ProDisc-C 
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However , around 5 years , a statistically significant divergence emerged , where the rate of adjacent-level surgery rose steeply for ACDF .
Index-level reoperations were less frequent with CDA in both the short- and long-term .
These data indicate CDA may have a superior longevity to ACDF with regard to need for subsequent adjacent-level operation