Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: a randomized controlled clinical trial. Prospective, randomized, multicenter study of cervical arthroplasty: 269 patients from the Kineflex|C artificial disc investigational device exemption study with a minimum 2-year follow-up: clinical article. The ProDisc-C prosthesis: clinical and radiological experience 1 year after surgery. Vertical bone augmentation versus 7-mm-long implants in posterior atrophic mandibles. Results of a randomised controlled clinical trial of up to 4 months after loading. Comparison of BRYAN cervical disc arthroplasty with anterior cervical decompression and fusion: clinical and radiographic results of a randomized, controlled, clinical trial. Autograft versus interbody fusion cage without plate fixation in the cervical spine: a randomized clinical study using radiostereometry. Lumbar disc arthroplasty with Maverick disc versus stand-alone interbody fusion: a prospective, randomized, controlled, multicenter investigational device exemption trial. A prospective, randomized study comparing the results of open discectomy with those of video-assisted arthroscopic microdiscectomy. Clinical outcomes with the Prestige II cervical disc: preliminary results from a prospective randomized clinical trial.
The authors report the results of a prospective randomized 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).
                Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and randomly 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.
                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. Cervical total disc replacement (CTDR) represents a relatively novel procedure intended to address some of the shortcomings associated with anterior cervical discectomy and fusion (ACDF) by preserving motion at the treated level. This prospective, randomized, multicenter study evaluates the safety and efficacy of a new metal-on-metal CTDR implant (Kineflex|C) by comparing it with ACDF in the treatment of single-level spondylosis with radiculopathy.
                The study was a prospective, randomized US FDA Investigational Device Exemption (IDE) pivotal trial conducted at 21 centers across the US. The primary clinical outcome measures included the Neck Disability Index (NDI), visual analog scale (VAS) scores, and a composite measure of clinical success. Patients were randomized to CTDR using the Kineflex|C (SpinalMotion, Inc.) cervical artificial disc or ACDF using structural allograft and an anterior plate.
                A total of 269 patients were enrolled and randomly assigned to either CTDR (136 patients) or to ACDF (133 patients). There were no significant differences between the CTDR and ACDF groups when comparing operative time, blood loss, length of hospital stay, or the reoperation rate at the index level. The overall success rate was significantly greater in the CTDR group (85%) compared with the ACDF group (71%) (p = 0.05). In both groups, the mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the 24-month follow-up (p < 0.0001). Similarly, the VAS pain scores improved significantly by 6 weeks and remained significantly improved through the 24-month follow-up (p < 0.0001). The range of motion (ROM) in the CTDR group decreased at 3 months but was significantly greater than the preoperative mean at 12- and 24-month follow-up. The ROM in the ACDF group was significantly reduced by 3 months and remained so throughout the follow-up. Adjacent-level degeneration was also evaluated in both groups from preoperatively to 2-year follow-up and was classified as none, mild, moderate, or severe. Preoperatively, there were no significant differences between groups when evaluating the different levels of adjacent-level degeneration. At the 2-year follow-up, there were significantly more patients in the ACDF group with severe adjacent-level radiographic changes (p < 0.0001). However, there were no significant differences between groups in adjacent-level reoperation rate (7.6% for the Kineflex|C group and 6.1% for the ACDF group).
                Cervical total disc replacement allows for neural decompression and clinical results comparable to ACDF. Kineflex|C was associated with a significantly greater overall success rate than fusion while maintaining motion at the index level. Furthermore, there were significantly fewer Kineflex|C patients showing severe adjacent-level radiographic changes at the 2-year follow-up. These results from a prospective, randomized study support that Kineflex|C CTDR is a viable alternative to ACDF in select patients with cervical radiculopathy. This is a prospective randomized and controlled study, approved by the local ethical committee of Saarland (Germany).
                The aim of the current study was to analyze segmental motion following artificial disc replacement using disc prosthesis over 1 year. A second aim was to compare both segmental motion as well as clinical result to the current gold standard (anterior cervical discectomy and fusion [ACDF]).
                ACDF may be considered to be the gold standard for treatment of symptomatic degenerative disc disease within the cervical spine. However, fusion may result in progressive degeneration of the adjacent segments. Therefore, disc arthroplasty has been introduced. Among these, artificial disc replacement seems to be promising. However, segmental motion should be preserved. This, again, is very difficult to judge and has not yet been proven.
                A total of 49 patients with cervical disc herniation were enrolled and assigned to either study group (receiving a disc prosthesis) or control group (receiving ACDF, using a cage with bone graft and an anterior plate). Roentgen stereometric analysis (RSA) was used to quantify intervertebral motion immediately as well as 3, 6, 12, 24, and 52 weeks after surgery. Also, clinical results were judged using visual analog scale and neuro-examination at even RSA follow-up.
                Cervical spine segmental motion decreased over time in the presence of disc prosthesis or fusion device. However, the loss segmental motion is significantly higher in the fusion group, when looked at 3, 6, 12, 24, and 52 weeks after surgery. We observed significant pain reduction in neck and arm after surgery, without significant difference between both groups.
                Cervical spine disc prosthesis remains cervical spine segmental motion within the first 1 year after surgery. The clinical results are the same when compared with the early results following ACDF. To evaluate whether 7-mm-long implants could be a suitable alternative to longer implants placed in vertically augmented bone for the treatment of atrophic posterior mandibles.
                Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on a computed tomography scan above the mandibular canal were randomised to receive either two to three submerged 7-mm-long NanoTite External Hex implants (Biomet 3i) or 10-mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with anorganic bovine bone blocks (Bio-Oss) using a sandwich technique and resorbable barriers. The grafts were left healing for 5 months before placing the implants, which were submerged. Four months after implant placement, provisional acrylic prostheses were delivered. Definitive screw-retained metal-ceramic prostheses were delivered 4 months later. Outcome measures were: prosthesis and implant failures, any complications, and time needed to fully recover mental nerve sensitivity. All patients were followed up to the delivery of the final restorations (4 months after loading).
                No patient dropped out. In two patients of the augmented group, there was not enough space to place 10-mm or longer implants as planned and 7-mm-long implants were used instead. The most likely reason for this is that the Bio-Oss blocks fractured in many pieces at placement. One prosthesis could not be placed when planned in the 7-mm group versus three prostheses in the augmented group, because of failure of one implant in each patient. The difference was not statistically significant. All implants were successfully replaced and final prostheses delivered. Four complications (wound dehiscence) occurred during graft healing in the augmented group (one possibly associated with the failure of one implant) versus none in the 7-mm-long implant group. The difference was not statistically significant. No patient suffered from permanent paraesthesia of the alveolar inferior nerve; however, sensitivity was recovered significantly faster in the short implant group.
                The early results of this study suggest that, when the residual bone height over the mandibular canal is between 7 and 8 mm, 7-mm short implants might be a preferable choice since the treatment is faster, cheaper and associated with less morbidity than vertical bone augmentation. These preliminary results must be confirmed by follow-ups of 5 years or more in order to monitor the performance of short implants over time. A prospective, randomized, multicenter study of surgical treatment of cervical disc disease.
                To assess the safety and efficacy of cervical disc arthroplasty using a new arthroplasty device at 24-months follow-up.
                Cervical disc arthroplasty preserves motion in the cervical spine. It is an alternative to fusion after neurologic decompression, whereas anterior decompression and fusion provides a rigorous comparative benchmark of success.
                We conducted a randomized controlled multicenter clinical trial enrolling patients with cervical disc disease. Ultimately 242 received the investigational device (Bryan Cervical Disc), and 221 patients underwent a single-level anterior cervical discectomy and decompression and fusion as a control group. Patients completed clinical and radiographic follow-up examinations at regular intervals for 2 years after surgery.
                Analysis of 12- and 24-month postoperative data showed improvement in all clinical outcome measures for both groups; however, 24 months after surgery, the investigational group patients treated with the artificial disc had a statistically greater improvement in the primary outcome variables: Neck disability index score (P = 0.025) and overall success (P = 0.010). With regard to implant- or implant/surgical-procedure-associated serious adverse events, the investigational group had a rate of 1.7% and the control group, 3.2%. There was no statistical difference between the 2 groups with regard to the rate of secondary surgical procedures performed subsequent to the index procedure. Patients who received the artificial cervical disc returned to work nearly 2 weeks earlier than the fusion patients (P = 0.015).
                Two-year follow-up results indicate that cervical disc arthroplasty is a viable alternative to anterior cervical discectomy and fusion in patients with persistently symptomatic, single-level cervical disc disease. A primary object with a fusion cage is avoidance of graft collapse with subsequent subsidence and malalignment of the cervical spine that is observed after bone grafting alone. No randomized studies exist that demonstrate the difference between these two methods in terms of graft subsidence and angulation of the fused segment. The size of the study population was calculated to be 24 patients to reach a significant difference at the 95% CI level. Patients with one-level cervical radiculopathy scheduled for surgery were randomized to anterior discectomy and fusion (ACDF) with autograft or to fusion cage, both without plate fixation. Tantalum markers were inserted in the two adjacent vertebrae at the end of surgery. Radiostereometry was performed immediately postoperatively and at regular intervals for 2 years. Questionnaires were used to evaluate the clinical outcome and an unbiased observer graded the outcome after 2 years. No significant differences were found between the two methods after 2 years in regard of narrowing of the disc space (mean 1.7 and 1.4 mm, respectively) or deformation of the fused segment into flexion (mean 7.7 degrees and 4.6 degrees , respectively). Patients in the cage group had a significantly better clinical outcome. The findings of subsidence and flexion deformation of the fused segment after 2 years seem to be of no clinical importance after one-level cervical disc surgery. However, in multi-level surgery using the same methods, an additive effect of the deformations of the fused segments may affect the clinical outcome. Randomized, controlled, multicenter, investigational device exemption trial.
                To investigate the safety and effectiveness of the first two-piece, metal-on-metal lumbar disc prosthesis for treating patients with single-level degenerative disc disease.
                For patients with degenerative disc disease unresponsive to conservative measures, lumbar disc arthroplasty provides an alternative to fusion designed to relieve persistent discogenic pain and maintain motion.
                After 2:1 randomization, 577 patients were treated in either the investigational group (405), receiving lumbar disc arthroplasty, or the control group (172), receiving anterior lumbar interbody fusion. Patients were evaluated preoperatively, at surgery/discharge, and at 1.5, 3, 6, 12, and 24 months after surgery. The primary study endpoint was overall success, a composite measure of safety and effectiveness as recommended by the Food and Drug Administration and defined in the protocol.
                Both treatment groups demonstrated significant improvements compared with preoperative status. The investigational group had statistically superior outcomes (P < 0.05) at all postoperative evaluations in Oswestry Disability Index, back pain, and Short Form-36 Physical Component Summary scores as well as patient satisfaction. Investigational patients had longer surgical times (P < 0.001) and greater blood loss (P < 0.001) than did control patients; however, hospitalization stays were similar for both groups. Investigational patients had fewer implant or implant/surgical procedure-related adverse events (P < 0.001). Return-to-work intervals were reduced for investigational patients. Disc height and segmental angular motion were maintained throughout the study in the investigational group. In the investigational group, overall success superiority was found when compared to the control group as defined by the Food and Drug Administration Investigational Device Exemption protocol.
                The investigational group consistently demonstrated statistical superiority versus fusion on key clinical outcomes including improved physical function, reduced pain, and earlier return to work. The usefulness of video-assisted arthroscopic microdiscectomy for the treatment of a herniated lumbar disc has been studied previously. In the current prospective, randomized study, the results of this procedure were compared with those of conventional open laminotomy and discectomy.
                Sixty patients who had objective evidence of a single intracanalicular herniation of a lumbar disc caudad to the first lumbar vertebra were randomized into two groups consisting of thirty patients each; Group 1 was managed with open laminotomy and discectomy, and Group 2 was managed with video-assisted arthroscopic microdiscectomy. None of the patients had had a previous operation on the low back, and all had failed to respond to nonoperative measures. Analysis of the outcomes of both procedures was based on the patient's self-evaluation before and after the operation, the preoperative and postoperative clinical findings, and the patient's ability to return to a functional status. The patients were followed for nineteen to forty-two months postoperatively.
                On the basis of the patient's preoperative and postoperative self-evaluation, the findings on physical examination, and the patient's ability to return to work or to normal activity, twenty-eight patients (93 percent) in Group 1 and twenty-nine patients (97 percent) in Group 2 were considered to have had a satisfactory outcome. The mean duration of postoperative disability before the patients were able to return to work was considerably longer in Group 1 than in Group 2 (forty-nine compared with twenty-seven days). The patients in Group 1 used narcotics for a longer duration postoperatively. No neurovascular complications or infections were encountered in either group.
                Although the rate of satisfactory outcomes was approximately the same in both groups, the patients who had had an arthroscopic microdiscectomy had a shorter duration of postoperative disability and used narcotics for a shorter period. These findings suggest that arthroscopic microdiscectomy may be useful for the operative treatment of specific symptoms, including radiculopathy, that are caused by lumbar disc herniation, provided that patients are properly selected--that is, they must have a herniated disc at a single level as confirmed on imaging studies, have failed to respond to nonoperative management, have no evidence of spinal stenosis, and have a herniation not exceeding one-half of the anteroposterior diameter of the spinal canal. Moreover, the surgeon must be familiar with this technique and must have received training in its use. A prospective, randomized clinical trial was conducted to compare the Prestige II Cervical Disc with anterior decompression and fusion for the treatment of single-level degenerative disease. Standardized clinical outcome measures and radiographic examinations were used at prescribed postoperative intervals to compare the treatment groups.
                Patients with symptomatic single-level cervical disc disease who met the inclusion/exclusion criteria defined in the protocol were randomized to receive the Prestige II disc or iliac crest autograft fusion. All patients underwent a standardized neurological and radiographic examination and completed outcomes questionnaires (Neck Disability Index and Short Form-36) preoperatively and at each postoperative interval (6 weeks and 3, 6, 12, and 24 months). Two independent radiologists reviewed all x-ray films and assessed motion at the treated level and adjacent segments. Standard statistical methods were used to compare all outcome measures. Preliminary results in 55 patients enrolled in the study are presented. Several patients have reached the final (24-month) follow-up interval. Clinical and radiographic results are encouraging, with significant improvement seen in both treatment groups. Radiographic results show that the Prestige II disc maintains motion at the treated level without adjacent-segment compromise.
                Cervical spine arthroplasty is an exciting and rapidly developing surgical treatment option. An objective comparison with fusion is important to advance this option. This is the first prospective randomized trial in which cervical arthroplasty is compared with fusion. The preliminary results from this limited number of patients indicate that the Prestige II disc is potentially a viable alternative to fusion for primary cervical disc disease; however, further clinical studies with larger sample sizes will be required to show statistical equivalence.
There was a tendency for clinical results to be in favour of arthroplasty; often these were statistically significant. However, differences in effect size were invariably small and not clinically relevant for all primary outcomes. Significance was often gained or lost in the varying sensitivity analyses, probably owing to the relatively small number of studies, in combination with the small differences that were found. Given the fact that all of the included studies were not blinded, this could be due to patient or carer expectations. However, at this time both treatments can be seen as valid options with respect to results at a maximum of one to two years. Given the current absence of truly long-term results, use of these mobile disc prostheses should still be limited to clinical trials.There was high-quality evidence that the goal of preservation of segmental mobility in arthroplasty was met. A statistically significant effect on the incidence of secondary symptoms at adjacent levels, the primary goal of arthroplasty over fusion, was not found at one to two years. If there was a protective effect, this should become clearer over time. A future update, when studies with 'truly long-term' results (five years or more) become available, should focus on this issue.