ProDisc artificial total lumbar disc replacement: introduction and early results from the United States clinical trial. Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. 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. A prospective, randomized, multicenter Food and Drug Administration investigational device exemptions study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: part I: evaluation of clinical outcomes. Prospective, randomized trial of metal-on-metal artificial lumbar disc replacement: initial results for treatment of discogenic pain. Results of the prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of the ProDisc-L total disc replacement versus circumferential fusion for the treatment of 1-level degenerative disc disease. Total disc replacement compared to lumbar fusion: a randomised controlled trial with 2-year follow-up. Neurological complications of lumbar artificial disc replacement and comparison of clinical results with those related to lumbar arthrodesis in the literature: results of a multicenter, prospective, randomized investigational device exemption study of Charité intervertebral disc. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004. The ProDisc-C prosthesis: clinical and radiological experience 1 year after surgery.
Multicenter prospective randomized study of artificial disc replacement (ProDisc) versus circumferential fusion (standard of care) for one- and two-level degenerative disc disease. This is an interim analysis on patients seen at the Spine Institute Saint John's Health Center, Santa Monica, California.
                To evaluate early pain and functional outcomes of patients treated with disc replacement or fusion and to assess the capacity of this intervertebral disc replacement for preserving motion in the lumbar spine.
                Disc replacement is intended to reduce pain via removal of the diseased disc while restoring physiologic motion and height at the affected level. The long-term physiologic advantage of disc replacement to fusion is that preservation of motion may prevent additional degeneration at adjacent levels.
                Patients meeting inclusion criteria were consented for study. Randomization was performed using a 2 to 1 ratio of disc replacement procedure to a fusion procedure. Patients rated their pain on the Visual Analogue Scale and completed the Oswestry Disability Index questionnaire. Radiographs were taken. Assessments were made before surgery and after surgery at 6 weeks, 3 months, 6 months, and 1 year (ongoing). Changes from preoperative pain, disability, or motion were separately evaluated as a function of treatment using repeated measures mixed design analysis of variance.
                This analysis includes data up to 6 months from the first 53 randomized patients. There were 35 patients who underwent disc replacements, and 18 patients had fusion procedures. Disc replacement patients had a significant reduction in pain and disability at earlier evaluations. By 6 months, the relative improvement on both the Visual Analogue Scale and Oswestry (both, P < 0.05) were similar for disc replacement and fusion patients. Greater motion was found at L4-L5 for disc replacement patients (P < 0.05) than fusion patients. A similar trend was noted at L5-S1 (P was not significant).
                Disc replacement patients reported significantly less pain (Visual Analogue Scale) and disability (Oswestry) in the early period following surgery compared to fusion patients. This difference disappeared by 6 months. When compared to fusion, the disc replacement allowed preservation of motion at L4-L5 with a similar trend at L5-S1. Single blind randomized study.
                To compare the effectiveness of lumbar instrumented fusion with cognitive intervention and exercises in patients with chronic low back pain and disc degeneration.
                To the authors' best knowledge, only one randomized study has evaluated the effectiveness of lumbar fusion. The Swedish Lumbar Spine Study reported that lumbar fusion was better than continuing physiotherapy and care by the family physician.
                Sixty-four patients aged 25-60 years with low back pain lasting longer than 1 year and evidence of disc degeneration at L4-L5 and/or L5-S1 at radiographic examination were randomized to either lumbar fusion with posterior transpedicular screws and postoperative physiotherapy, or cognitive intervention and exercises. The cognitive intervention consisted of a lecture to give the patient an understanding that ordinary physical activity would not harm the disc and a recommendation to use the back and bend it. This was reinforced by three daily physical exercise sessions for 3 weeks. The main outcome measure was the Oswestry Disability Index.
                At the 1-year follow-up visit, 97% of the patients, including 6 patients who had either not attended treatment or changed groups, were examined. The Oswestry Disability Index was significantly reduced from 41 to 26 after surgery, compared with 42 to 30 after cognitive intervention and exercises. The mean difference between groups was 2.3 (-6.7 to 11.4) (P = 0.33). Improvements inback pain, use of analgesics, emotional distress, life satisfaction, and return to work were not different. Fear-avoidance beliefs and fingertip-floor distance were reduced more after nonoperative treatment, and lower limb pain was reduced more after surgery. The success rate according to an independent observer was 70% after surgery and 76% after cognitive intervention and exercises. The early complication rate in the surgical group was 18%.
                The main outcome measure showed equal improvement in patients with chronic low back pain and disc degeneration randomized to cognitive intervention and exercises, or lumbar fusion. 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. A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial.
                The purpose of this study was to compare the safety and effectiveness of lumbar total disc replacement, using the CHARITE artificial disc (DePuy Spine, Raynham, MA), with anterior lumbar interbody fusion, for the treatment of single-level degenerative disc disease from L4-S1 unresponsive to nonoperative treatment.
                Reported results of lumbar total disc replacement have been favorable, but studies have been limited to retrospective case series and/or small sample sizes.
                Three hundred four (304) patients were enrolled in the study at 14 centers across the United States and randomized in a 2:1 ratio to treatment with the CHARITE artificial disc or the control group, instrumented anterior lumbar interbody fusion. Data were collected pre- and perioperatively at 6 weeks and at 3, 6, 12, and 24 months following surgery. The key clinical outcome measures were a Visual Analog Scale assessing back pain, the Oswestry Disability Index questionnaire, and the SF-36 Health Survey.
                Patients in both groups improved significantly following surgery. Patients in the CHARITE artificial disc group recovered faster than patients in the control group. Patients in the CHARITE artificial disc group had lower levels of disability at every time interval from 6 weeks to 24 months, compared with the control group, with statistically lower pain and disability scores at all but the 24 month follow-up (P < 0.05). At the 24-month follow-up period, a significantly greater percentage of patients in the CHARITE artificial disc group expressed satisfaction with their treatment and would have the same treatment again, compared with the fusion group (P < 0.05). The hospital stay was significantly shorter in the CHARITE artificial disc group (P < 0.05). The complication rate was similar between both groups.
                This prospective, randomized, multicenter study demonstrated that quantitative clinical outcome measures following lumbar total disc replacement with the CHARITE artificial disc are at least equivalent to clinical outcomes with anterior lumbar interbody fusion. These results support earlier reports in the literature that total disc replacement with the CHARITE artificial disc is a safe and effective alternative to fusion for the surgical treatment of symptomatic disc degeneration in properly indicated patients. The CHARITE artificial disc group demonstrated statistically significant superiority in two major economic areas, a 1-day shorter hospitalization, and a lower rate of reoperations (5.4% compared with 9.1%). At 24 months, the investigational group had a significantly higher rate of satisfaction (73.7%) than the 53.1% rate of satisfaction in the control group (P = 0.0011). This prospective randomized multicenter study also demonstrated an increase in employment of 9.1% in the investigational group and 7.2% in the control group. This study presents data on 67 patients from 2 study sites involved in the multicenter, prospective, randomized, controlled investigational device exemption study of FlexiCore artificial disc replacement versus fusion with a 2-year follow-up.
                To compare the outcomes achieved with the FlexiCore disc replacement versus standard circumferential fusion for the treatment of discogenic pain due to single level degenerative disc disease (DDD).
                The FlexiCore Intervertebral Disc (Stryker Spine, Allendale, NJ) is a metal-on-metal artificial lumbar disc replacement device currently being studied for the treatment of DDD under an investigational device exemption protocol approved by the United States Food and Drug Administration. Artificial disc replacement in the spine is designed to preserve motion at the intervertebral segment and subsequently reduce adjacent segment degeneration. This is the first study to compare a metal-on-metal artificial lumbar disc replacement with circumferential fusion. Here we report the 2-year follow-up results.
                Forty-four patients were treated with the FlexiCore and 23 patients were treated with fusion. The FlexiCore treatment group consisted of 23 men and 21 women, with an average age of 36 and an average body mass index of 28. Thirty-two of the FlexiCore surgeries were performed at L5-S1, and 12 were performed at L4-L5. The control treatment group consisted of 10 men and 13 women, with an average age of 41 and an average body mass index of 28. Seventeen of the control surgeries were performed at L5-S1, 5 were performed at L4-L5, and 1 was a 2-level fusion performed at L4-L5 and L5-S1. Prospective data were collected before surgery and after surgery at 6 weeks, and at 3, 6, 12, and 24 months. Disability and pain were assessed using the Oswestry Disability Index and the Visual Analog Scale. Range of motion was determined by independent radiologic assessment of flexion/extension and lateral bending radiographs.
                The mean Oswestry Disability Index scores were 62 (FlexiCore) and 58 (control) before surgery, 36 (FlexiCore) and 50 (control) at 6 weeks, and 6 (FlexiCore) and 12 (control) at 2 years. The mean Visual Analog Scale scores were 86 (FlexiCore) and 82 (control) before surgery, 32 (FlexiCore) and 43 (control) at 6 weeks, and 16 (FlexiCore) and 20 (control) at 2 years. The FlexiCore group's angular rotation averaged 2.8 degrees before surgery and 3.8 degrees at 6 weeks after surgery. The group's lateral bending averaged 4.7 degrees before surgery and 4.2 degrees at 6 weeks after surgery. The average operative time (skin to skin) was 82 minutes for the FlexiCore group versus 179 minutes for the control group (P < 0.001). The average estimated blood loss was 97 mL for the FlexiCore group versus 179 mL for the control group (P < 0.02). The average hospital stay was 2 days for the FlexiCore group versus 3 days for the control group (P < 0.005).
                These initial results from 2 study sites demonstrate that the FlexiCore compares very favorably to circumferential fusion for the treatment of lumbar DDD unresponsive to conservative treatment. These results are not intended to represent the overall study results. A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial.
                To evaluate the safety and effectiveness of the ProDisc-L (Synthes Spine, West Chester, PA) lumbar total disc replacement compared to circumferential spinal fusion for the treatment of discogenic pain at 1 vertebral level between L3 and S1.
                As part of the Investigational Device Exemption clinical trial, favorable single center results of lumbar total disc replacement with the ProDisc-L have been reported previously.
                Two hundred eighty-six (286) patients were treated on protocol. Patients were evaluated before and after surgery, at 6 weeks, 3, 6, 12, 18, and 24 months. Evaluation at each visit included patient self-assessments, physical and neurologic examinations, and radiographic evaluation.
                Safety of ProDisc-L implantation was demonstrated with 0% major complications. At 24 months, 91.8% of investigational and 84.5% of control patients reported improvement in the Oswestry Low Back Pain Disability Questionnaire (Oswestry Disability Index [ODI]) from preoperative levels, and 77.2% of investigational and 64.8% of control patients met the > or =15% Oswestry Disability Index improvement criteria. Overall neurologic success in the investigational group was superior to the control group (91.2% investigational and 81.4% control; P = 0.0341). At 6 weeks and 3 months follow-up time points, the ProDisc-L patients recorded SF-36 Health Survey scores significantly higher than the control group (P = 0.018, P = 0.0036, respectively). The visual analog scale pain assessment showed statistically significant improvement from preoperative levels regardless of treatment (P < 0.0001). Visual analog scale patient satisfaction at 24 months showed a statistically significant difference favoring investigational patients over the control group (P = 0.015). Radiographic range of motion was maintained within a normal functional range in 93.7% of investigational patients and averaged 7.7 degrees.
                ProDisc-L has been found to be safe and efficacious. In properly chosen patients, ProDisc-L has been shown to be superior to circumferential fusion by multiple clinical criteria. The study design includes a prospective, randomised controlled study comparing total disc replacement (TDR) with posterior fusion. The main objective of this study is to compare TDR with lumbar spinal fusion, in terms of clinical outcome, in patients referred to a spine clinic for surgical evaluation. Fusion is effective for treating chronic low back pain (LBP), but has drawbacks, such as stiffness and possibly adjacent level degradation. Motion-preserving options have emerged, of which TDR is frequently used because of these drawbacks. How the results of TDR compare to fusion, however, is uncertain. One hundred and fifty-two patients with a mean age of 40 years (21-55) were included: 90 were women, and 80 underwent TDR. The patients had not responded to a conservative treatment programme and suffered from predominantly LBP, with varying degrees of leg pain. Diagnosis was based on clinical examination, radiographs, MRI, and in unclear cases, diagnostic injections. Outcome measures were global assessment (GA), VAS for back and leg pain, Oswestry Disability Index, SF36 and EQ5D at 1 and 2 years. Follow-up rate was 100%, at both 1 and 2 years. All outcome variables improved in both groups between preoperative and follow-up assessment. The primary outcome measure, GA, revealed that 30% in the TDR group and 15% in the fusion group were totally pain-free at 2 years (P = 0.031). TDR patients had reached maximum recovery in virtually all variables at 1 year, with significant differences compared to the fusion group. The fusion patients continued to improve and at 2 years had results similar to TDR patients apart from numbers of pain-free. Complications and reoperations were similar in both groups, but pedicle screw removal as additive surgery, was frequent in the fusion group. One year after surgery, TDR was superior to spinal fusion in clinical outcome, but this difference had diminished by 2 years, apart from (VAS for back pain and) numbers of pain-free. The long-term benefits have yet to be examined. Arthrodesis is the gold standard for surgical treatment of lumbar degenerative disc disease (DDD). Solid fusion, however, can cause stress and increased motion in the segments adjacent to the fused level. This may initiate and/or accelerate the adjacent-segment disease process. Artificial discs are designed to restore and maintain normal motion of the lumbar intervertebral segment. Restoring and maintaining normal motion of the segment reduces stresses and loads on adjacent level segments. A US Food and Drug Administration Investigational Device Exemptions multicentered study of the Charité artificial disc was completed. The control group consisted of individuals who underwent anterior lumbar interbody fusion involving BAK cages and iliac crest bone graft. This is the first report of Class I data in which a lumbar artificial disc is compared with lumbar fusion.
                Of 304 individuals enrolled in the study, 205 were randomized to the Charité disc-treated group and 99 to the BAK fusion-treated (control) group. Neurological status was equivalent between the two groups at 6, 12, and 24 months postoperatively. The number of patients with major, minor, or other neurological complications was equivalent. There was a greater incidence of both major and minor complications in the BAK fusion group at 0 to 42 days postoperatively. Compared with data reported in the lumbar fusion literature, the Charité disc-treated patients had equivalent or better mean changes in visual analog scale and Oswestry Disability Index scores.
                The Charité artificial disc is safe and effective for the treatment of single-level lumbar DDD, resulting in no higher incidence of neurological complications compared with BAK-assisted fusion and leading to equivalent or better outcomes compared with those obtained in the control group and those reported in the lumbar fusion literature. 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.
Although statistically significant, the differences between disc replacement and conventional fusion surgery for degenerative disc disease were not beyond the generally accepted clinical important differences with respect to short-term pain relief, disability and Quality of Life. Moreover, these analyses only represent a highly selected population. The primary goal of prevention of adjacent level disease and facet joint degeneration by using total disc replacement, as noted by the manufacturers and distributors, was not properly assessed and not a research question at all. Unfortunately, evidence from observational studies could not be used because of the high risk of bias, while these could have improved external validity assessment of complications in less selected patient groups. Non-randomised studies should however be very clear about patient selection and should incorporate independent, blinded outcome assessment, which was not the case in the excluded studies. Therefore, because we believe that harm and complications may occur after years, we believe that the spine surgery community should be prudent about adopting this technology on a large scale, despite the fact that total disc replacement seems to be effective in treating low-back pain in selected patients, and in the short term is at least equivalent to fusion surgery.