***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 
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    ***EXAMPLES*** 
    Input: This retrospective consecutive case study evaluated the effect of anterior plating on multilevel anterior cervical decompressions and fusions in smokers and non-smokers . Multilevel anterior cervical decompression and fusion surgery in smokers provides an important challenge . Higher nonfusion rates in smokers have been reported . Cigarette smoking has been shown to interfere with bone metabolism and revascularization and to suppress bone formation . One hundred six patients underwent anterior cervical decompression and fusion using autografts or allografts and anterior plating . The minimum follow-up was 12 months . The mean age was 50.12 years ( + /- 11.72 ; range , 27 to 80 years ) .  Autografts were used in 90 patients and allograft in 16 . The mean level fused was 2.74 ( + /- 0.61 ) . Forty-six ( 45.5 % ) patients were smokers .  Successful fusion was achieved in all but three patients ( 97.17 % ) . C5 root weakness was seen in four patients ( 3.8 % ) ; two patients experienced acute airway obstruction , of which one required tracheotomy . Temporary recurrent laryngeal nerve palsy developed in three ( 2.8 % ) patients . A fusion rate of 97 % was achieved in multilevel anterior cervical decompression and fusions using anterior plating . No difference in fusion rates between smokers and nonsmokers was seen . Anterior cervical plating markedly improved the fusion rate in smokers 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 Study Design : Prospect i ve study . Objective : The purpose of this study was to compare the long-term clinical and radiologic outcomes of hybrid surgery ( HS ) and 2-level anterior cervical discectomy and fusion ( 2-ACDF ) in patients with 2-level cervical disk disease . Summary of Background Data : In a previous study with a 2-year follow-up , HS was shown to be superior to 2-ACDF , with a better Neck Disability Index ( NDI ) score , less postoperative neck pain , faster C2–C7 range of motion ( ROM ) recovery , and less adjacent ROM increase . Material s and Methods : Between 2004 and 2006 , 40 patients undergoing 2-level cervical disk surgery at our hospital were identified as 2-level degenerative disk disease . Forty patients were included in the previous study ; 35 patients were followed up for 5 years . Patients completed the NDI and grade d their pain intensity before surgery and at routine postoperative until 5 years . Dynamic cervical radiographs were obtained before surgery and at routine postoperative intervals and the angular ROM for C2–C7 and adjacent segments was measured . Results : The HS group had better NDI recovery until 3 years after surgery ( P<0.05 ) . Postoperative neck pain was lower in the HS group at 1 and 3 years after surgery ( P<0.05 ) , but arm pain relief was not differently relieved . The HS group showed more angular ROM for C2–C7 at 2 and 3 years after surgery . The superior adjacent segment ROM showed hypermobility in the 2-ACDF group and hypomobility in the HS group at all follow-up periods without statistically significance , but the inferior adjacent segment ROM differed significantly ( P<0.05 ) . Conclusion : HS is superior to 2-ACDF ; it leads to better NDI recovery , less postoperative neck pain , faster C2–C7 ROM recovery , and less adjacent ROM increase over a 2-year follow-up , but these benefits of HS become similar to those of 2-ACDF with 5 years of follow-up Purpose Although several studies have established the safety and efficacy of cervical disc arthroplasty ( CDA ) as compared to anterior cervical discectomy and fusion ( ACDF ) , few studies have investigated the role of hybrid surgery ( HS ) that incorporates ACDF and CDA techniques in multilevel cervical degenerative disc disease ( MLCDDD ) . Methods This prospect i ve study enrolled patients with MLCDDD who underwent HS . Twenty consecutive patients who underwent HS were compared with patients who underwent ACDF and CDA  at the same level of surgery . Patients were followed up for more than 2 years . Intraoperative parameters , clinical features and outcome scores were recorded . Radiological assessment s included overall range of motion ( ROM ) , disc height ( DHI ) , and changes in adjacent disc spaces . Results Duration of surgery was significantly shorter for ACDF compared with HS and CDA ( P < 0.05 ) . The VAS , SF-36 , JOA , and NDI scores improved significantly after surgery in all the patients without significant differences among the groups . Cervical ROM increased significantly in CDA and HS groups as compared with ACDF-treated patients ( P < 0.05 ) . The mean DHI at the treated level was significantly restored after surgery in all the groups . The HS group returned to work faster ( 30 days ) when compared with both ACDF ( 62 days ) and CDA ( 65 days ) ( P < 0.05 ) . Conclusion HS is an effective , reliable , and safe procedure for the treatment MLCDDD . Such a surgical construct is comparable to ACDF and CDA in terms of safety and feasibility . However , large , r and omized controlled trials are warranted The optimal surgical approach for cervical disk disease remains a matter of debate , especially for multilevel disease . The purpose of this study was to compare the results of 2 surgical strategies for cervical disk disease involving 3 levels : hybrid constructs , artificial disk replacement combined with midlevel anterior cervical diskectomy and fusion ( ACDF ) , and 3-level ACDF . The authors prospect ively compared patients who had cervical disk disease involving 3 levels that was treated with hybrid constructs or with 3-level ACDF .  Patients were asked to use the Neck Disability Index ( NDI ) to grade their pain intensity preoperatively and at routine postoperative intervals of 1 , 3 , 6 , 12 , and 24 months . Dynamic flexion and extension lateral cervical radiographs were obtained while in the st and ing position preoperatively and at the postoperative intervals . The angular range of motion for C2-C7 and the adjacent segments was measured using the Cobb method . Twenty-four patients were treated , 12 with hybrid constructs  and 12 with 3-level ACDF . Both groups had significant postoperative improvement in NDI scores and neck pain ( P<.05 ) . However , no significant difference was found between the groups ( P>.05 ) . The hybrid constructs group showed faster recovery of C2-C7 range of motion . Mean C2-C7 range of motion of the hybrid constructs group recovered to that of the preoperative value , but that of the 3-level ACDF group did not ( P<.05 ) . Range of motion of the superior and inferior adjacent segments showed significant differences between the 2 groups at 12 and 24 months postoperatively ( P<.05 ) . These findings suggest that the hybrid constructs is a safe and effective alternative for cervical disk disease involving 3 levels . The definite stabilization and maintained range of motion can be achieved right away , which can ensure a good preliminary clinical outcome Purpose Few studies have investigated the role of hybrid surgery ( HS )  that incorporates anterior cervical discectomy and fusion ( ACDF ) and artificial disc replacement ( ADR ) techniques . To our knowledge , this is the first study that provides a direct comparison of all three groups in terms of intra-operative parameters and outcomes with a minimum follow-up of 2 years . Methods Seven consecutive patients who underwent HS were matched with another seven patients who underwent ACDF and ADR based on levels of surgery . Prospect i ve data on demographics , pre-operative and post-operative assessment s , complications and functional scores ( VAS , NDI , EQ-5D health score and index ) were analysed using Mann – Whitney U test . Type I error was set at 5 % . Results Duration of surgery was significantly shorter for ACDF at 135 min ( p = 0.025 ) compared with HS and ADR . ACDF also had greater blood loss when compared with ADR ( p < 0.036 ) . ADR has the shortest duration of hospitalization followed by HS and ACDF ( p < 0.031 ) . The HS group returned to work fastest ( 54 days ) when compared with both ACDF ( 107 days ) and ADR ( 73 days ) with statistical significance seen between HS and ACDF ( p = 0.035 ) . Cervical range of motion ( ROM ) and functional scores did not show any significant differences . Conclusion HS is comparable to ACDF and ADR in terms of safety and feasibility . Findings of shorter in-hospital stay and earlier return to work in HS group may be further explored in large , r and omised controlled trials In cervical multi-level degenerative pathology , considering the morbidity of the extensive fusion techniques , some authors advocate for the multilevel disc replacement . This study compared the safety and efficacy of disc replacement with an unconstrained prosthesis in multi- versus single-level patients . A total of 231 patients with cervical degenerative disc disease ( DDD ) who were treated with cervical disc replacement and completed their 24 months follow-up were analyzed prospect ively : 175 were treated at one level , 56 at 2 levels or more . Comparison between both groups was based on usual clinical and radiological outcomes [ Neck Disability Index ( NDI ) , Visual Analog Scale ( VAS ) , Range of Motion , satisfaction ] . Safety assessment s , including complication and subsequent surgeries , were also documented and compared . Mean NDI and VAS scores for neck and arm pain were improved in both groups similarly . Improvement of mobility at treated segments was also similar . Nevertheless , in the multi-level group , analgesic use was significantly higher and occurrence of Heterotopic Ossification significantly lower than in the single-level group . Subject satisfaction was nearly equal , as 94.2 % of single-level group patients would undergo the surgery again versus 94.5 % in the multi-level group . The overall success rate did not differ significantly . Multi-level DDD is a challenging indication in the cervical spine . This study showed no major significant clinical difference between the two groups . We need further studies to know more about the impact of multi-level arthroplasty , especially on the adjacent segments , but these results demonstrate initial safety and effectiveness in this patient sample Abstract . Several work-related , psychosocial and individual factors have been verified as being related to neck and shoulder pain , but the role of pathology visualized by magnetic resonance imaging ( MRI ) remains unclear . In this study , the relationship between neck and shoulder pain 
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Conclusions HS is a novel surgical approach to treat mCDD , associated with a greater operative time , less intraoperative blood loss and comparable if not superior clinical outcomes compared to ACDF .