Prospective, multicenter study of 2-level cervical arthroplasty with a PEEK-on-ceramic artificial disc.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of a PEEK-on-ceramic cervical total disc replacement (cTDR) device for the treatment of 2-level cervical disc disease with radiculopathy and/or myelopathy. METHODS: The study was a prospective, nonrandomized, historically controlled FDA investigational device exemption trial evaluating the Simplify Cervical Artificial Disc for use at 2 levels. The anterior cervical discectomy and fusion (ACDF) control group was derived from a propensity score-matched (using subclassification) cohort of patients who participated in an earlier prospective trial in which similar indications were used. The follow-up duration was 24 months. The primary outcome was a 4-point composite success classification. Other validated clinical and radiographic assessments were also evaluated. RESULTS: The investigational group (n = 182) was compared with patients who underwent ACDF (n = 170) in a historical control group using propensity score analysis. The overall composite success rate was statistically significantly greater in the cTDR group compared with the ACDF group (86.7% vs 77.1%; p < 0.05). The mean Neck Disability Index scores improved significantly in both groups, with cTDR significantly lower at some follow-up points. At the 24-month follow-up, a minimum 15-point improvement in Neck Disability Index scores was achieved in 92.9% of the cTDR group and 83.5% of the ACDF group (p > 0.05). In both groups, neck and arm pain scores improved significantly (p < 0.05) by 6 weeks and improvement was maintained throughout follow-up. Segmental range of motion was maintained at both treated segments in the cTDR group. MRI performed in the cTDR group at 24 months postoperatively found minimal changes in facet joint degeneration. The rate of subsequent surgical intervention was 2.2% in the cTDR group and 8.8% in the ACDF group. CONCLUSIONS: This study adds to the growing body of literature supporting cTDR for 2-level cervical disc disease with radiculopathy or myelopathy. cTDR showed a superior overall success rate compared to ACDF, while maintaining motion. These results support that the Simplify disc is a viable alternative to ACDF in appropriately selected patients with 2-level cervical spondylosis.

Single-Level Cervical Disc Replacement Using a PEEK-on-Ceramic Implant: Results of a Multicenter FDA IDE Trial With 24-Month Follow-up.

BACKGROUND: Many early cervical total disc replacements (TDRs) produced motion through a ball-and-socket action, with metal endplates articulating with a plastic core. Polyetheretherketone (PEEK) is used increasingly for spinal implants due to its mechanical properties and lack of artifacts on imaging. A TDR was designed with titanium-coated PEEK endplates and a ceramic core. The purpose of this study was to compare this TDR with anterior cervical discectomy and fusion (ACDF) to treat single-level cervical disc degeneration. METHODS: This was a prospective, nonrandomized, historically controlled, multicenter US Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trial. Patients received the PEEK-on-ceramic Simplify® Cervical Artificial Disc (n = 150). The historic control group included 117 propensity-matched ACDF patients from an earlier IDE trial. The primary outcome was a composite success classification at the 24-month follow-up. Outcome measures included the Neck Disability Index (NDI), neurological status, adverse events, subsequent surgery, a visual analog scale assessing neck and arm pain, and the Dysphagia Handicap Index. Radiographic assessment included flexion/extension range of motion and heterotopic ossification. Facet joints were assessed at 24 months using MRI. RESULTS: The success rate was significantly greater in the TDR group vs the ACDF group (93.0% vs 73.6%; P < .001). Mean NDI, neck pain, and arm pain scores improved significantly in both groups at all follow-up points. Mean NDI scores in the TDR group were significantly lower than ACDF scores at all follow-up points. There were no significant differences in the rates of serious adverse events. The range of motion of the TDR level had increased significantly by 3 months and remained so throughout follow-up. Facet joint assessment by MRI in the TDR group showed little change from preoperation. CONCLUSIONS: The TDR had an acceptable safety profile and a significantly greater composite success rate than ACDF. These results support that the PEEK-on-ceramic TDR is a viable alternative to ACDF for single-level symptomatic disc degeneration. CLINICAL RELEVANCE: This study found that the PEEK-on-ceramic TDR is a viable treatment for symptoms related to cervical disc degeneration and offers similar or superior outcomes compared with fusion. LEVEL OF EVIDENCE: 2.

Economic Analysis of Transforaminal Lumbar Interbody Fusion Surgery Utilizing a Curved Bone Removal Device.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) represents a commonly performed spinal procedure that poses a significant financial burden on patients, hospitals and insurers. Reducing these costs, while maintaining efficacy, may be assisted by a new powered endplate preparation device, designed to shorten procedural time while offering positive impacts on other elements that contribute to the cost of care. OBJECTIVE: The aim of the study was to assess and compare the individual cost elements of TLIF procedures with and without the use of the device, to determine whether application of this technology translated into any material procedural savings. METHODS: The records of 208 single-level TLIF procedures in a single hospital were reviewed. Surgical time, length of hospital stay, blood loss, infection rate, and other parameters were compared for the cases where the device was used (device group; n = 143) and cases which used standard tools (control group; n = 65). The cost per unit of each element was derived from the literature, online resources, and the hospital's financial department. RESULTS: The analysis revealed a shorter surgery duration in the device group (23 min, after controlling for procedure year and patient characteristics; statistically significant at p < 0.001) and lower complication and readmission rates (p = 0.67 and p = 0.21, respectively) associated with the use of the device, leading to a statistically significant cost reduction of approximately 2060 US dollars (US$) (p < 0.01). CONCLUSION: The study suggests that use of the device may lead to a cost reduction and shorter procedure without deteriorating the clinical outcome.

Lumbar disc arthroplasty versus anterior lumbar interbody fusion: 5-year outcomes for patients in the Maverick disc investigational device exemption study.

OBJECTIVE: Despite evidence of its safety and effectiveness, the use of lumbar disc arthroplasty has been slow to expand due in part to concerns about late complications and the risks of revision surgery associated with early devices. More recently, FDA approval of newer devices and improving reimbursements have reversed this trend in the United States. Additional long-term data on lumbar disc arthroplasty are still needed. This study reports the 5-year results of the FDA investigational device exemption clinical trial of the Medtronic Spinal and Biologics' Maverick total disc replacement. METHODS: Patients with single-level degenerative disc disease from L4 to S1 were randomized 2:1 at 31 investigational sites. In the period from April 2003 to August 2004, 405 patients received the investigational device and 172 patients underwent the control procedure of anterior lumbar interbody fusion. Outcome measures included the Oswestry Disability Index (ODI), numeric rating scales (NRSs) for back and leg pain, the SF-36, disc height, interbody motion, heterotopic ossification (investigational device), adverse events (AEs), additional surgeries, and neurological status. Treatment was considered an overall success when all of the following criteria were met: 1) ODI score improvement ≥ 15 points over the preoperative score; 2) maintenance or improvement in neurological status compared with preoperatively; 3) disc height success, that is, no more than a 2-mm reduction in anterior or posterior height; 4) no serious AEs caused by the implant or by the implant and the surgical procedure; and 5) no additional surgery classified as a failure. RESULTS: Compared to that in the control group, improvement in the investigational group was statistically greater according to the ODI and SF-36 Physical Component Summary (PCS) at 1, 2, and 5 years; the NRS for back pain at 1 and 2 years; and the NRS for leg pain at 1 year. The rates of heterotopic ossification increased over time: 1.0% (4/382) at 1 year, 2.6% (9/345) at 2 years, and 5.9% (11/187) at 5 years. Investigational patients had fewer device-related AEs and serious device-related AEs than the control patients at both 2 and 5 years postoperatively. Noninferiority of the composite measure overall success was demonstrated at all follow-up intervals; superiority was demonstrated at 1 and 2 years. CONCLUSIONS: Lumbar disc arthroplasty is a safe and effective treatment for single-level lumbar degenerative disc disease, resulting in improved physical function and reduced pain up to 5 years after surgery.Clinical trial registration no.: NCT00635843 (clinicaltrials.gov).

Evaluation of Decompression and Interlaminar Stabilization Compared with Decompression and Fusion for the Treatment of Lumbar Spinal Stenosis: 5-year Follow-up of a Prospective, Randomized, Controlled Trial.

INTRODUCTION: If nonoperative treatment for lumbar stenosis fails, surgery may be considered. This traditionally includes decompression often combined with fusion. Desire for less extensive surgery led to developing new techniques and implants, including an interlaminar device designed with the goal of providing segmental stability without fusion, following decompression. The purpose of this study was to investigate 5-year outcomes associated with an interlaminar device. METHODS: This prospective, randomized, controlled trial was conducted at 21 centers. Patients with moderate to severe lumbar stenosis at one or two contiguous levels and up to Grade I spondylolisthesis were randomized (2:1 ratio) to decompression and interlaminar stabilization (D+ILS; n=215) using the coflex(®) Interlaminar Stabilization(®) device (Paradigm Spine, LLC) or decompression and fusion with pedicle screws (D+PS; n=107). Clinical evaluations were made preoperatively and at 6 weeks and 3, 6, 12, 18, 24, 36, 48, and 60 months postoperatively. Overall Food and Drug Administration success criteria required that a patient meet 4 criteria: 1) >15 point improvement in Oswestry Disability Index (ODI) score; 2) no reoperation, revision, removal, or supplemental fixation; 3) no major device-related complication; and 4) no epidural steroid injection after surgery. RESULTS: At 5 years, 50.3% of D+ILS vs. 44% of D+PS patients (p>0.35) met the composite success criteria. Reoperation/revision rates were similar in the two groups (16.3% vs. 17.8%; p >0.90). Both groups had statistically significant improvement through 60 months in ODI scores with 80.6% of D+ILS patients and 73.2% of D+PS patients demonstrating >15 point improvement (p>0.30). VAS, SF-12, and ZCQ scores followed a similar pattern of maintained significant improvement throughout follow-up. On the SF-12 and ZCQ, D+ILS group scores were statistically significantly better during early follow-up compared to D+PS. In the D+ILS group, foraminal height, disc space height, and range of motion at the index level were maintained through 5 years. CONCLUSION: Both treatment groups achieved and maintained statistically significant improvements on multiple outcome assessments throughout 5-year follow-up. On some clinical measures, there were statistically significant differences during early follow-up favoring D+ILS. At no point were there significant differences favoring D+PS. Results of this 5-year follow-up study demonstrate that decompression and interlaminar stabilization with coflex is a viable alternative to traditional decompression and fusion in the treatment of patients with moderate to severe stenosis at one or two lumbar levels. LEVEL OF EVIDENCE AND ETHICAL STATEMENTS: This is a Level I study. Institutional approval was received at each of the sites participating in the trial. Each patient gave informed consent to participate in the trial.

Retrograde ejaculation following single-level anterior lumbar surgery with or without recombinant human bone morphogenetic protein-2 in 5 randomized controlled trials: clinical article.

OBJECT: The aim of this study was to determine the incidence and assess specific risk factors in the postoperative development of retrograde ejaculation (RE) in men treated for degenerative lumbar disc disease at the L4-5 or L5-S1 level with stand-alone anterior interbody implants with or without recombinant human bone morphogenetic protein-2 (rhBMP-2). METHODS: Patients enrolled in 5 prospective, randomized, multicenter FDA-approved investigational device exemption studies were observed for a minimum of 2 years to assess the rate of RE. Five hundred eight men with symptomatic single-level lumbar degenerative disc disease with up to Grade 1 spondylolisthesis underwent anterior lumbar interbody surgery with stand-alone anterior implants at either L4-5 or L5-S1. All patient self-reported and physician-documented adverse events were recorded over the entire course of follow-up. In the investigational groups, 207 patients were treated with an open surgical procedure using dual paired constructs and rhBMP-2 on an absorbable collagen sponge. The control groups (n = 301) were treated with lumbar fusion cage implants and iliac crest autograft or a metal-on-metal disc arthroplasty device. Multivariate analyses of RE were performed to assess the influence of treatment (rhBMP-2), surgical approach, and treated level. Data were analyzed for each trial individually and for the data pooled from the 5 trials. RESULTS: Retrograde ejaculation occurred at the highest rates in the earliest clinical trial. Of the 146 men, 6 (4.1%) developed RE postoperatively. In subsequent studies, the rates of RE ranged from 0% to 2.1%. Combining the data from the 5 trials, RE was reported in 7 (3.4%) of the 207 patients who received the rhBMP-2 treatment compared with 5 (1.7%) of the 301 patients who received the autograft or lumbar disc treatment (p = 0.242, Fisher exact test). Cases of RE were reported in 7 (1.6%) of 445 patients who underwent a retroperitoneal spinal exposure; 5 RE cases were reported in 58 patients (8.6%) who underwent a transperitoneal approach. The difference in surgical approaches was significant (p = 0.007, Fisher exact test). There was no difference in the rate of RE based on the lumbar level exposed (p = 0.739). Multivariate analyses were consistent with the conclusions from Fisher exact tests. In the initial rhBMP-2 trial, after adjusting for effects of surgical approach and treated level, the difference in RE between the treatment groups (rhBMP-2 vs autograft or disc arthroplasty) was not significant (p = 0.177); however, the difference in RE between the retroperitoneal and transperitoneal approaches was significant (p = 0.029). CONCLUSIONS: In these 5 prospective randomized trials involving anterior lumbar interbody surgery, the use of rhBMP-2 was associated with a higher incidence of RE (3.4% vs 1.7%) but did not reach statistical significance. Based on surgical approach, the difference in rates of RE was statistically significant. This study reports on the outcomes of 5 prospective randomized FDA-approved investigational device exemption trials. Registration for studies became law in 2007. Four of these trials were completed before the law went into effect. The registration number for the lumbar disc arthroplasty trial is NCT00635843.

Lumbar disc arthroplasty with Maverick disc versus stand-alone interbody fusion: a prospective, randomized, controlled, multicenter investigational device exemption trial.

STUDY DESIGN: Randomized, controlled, multicenter, investigational device exemption trial. OBJECTIVE: 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. SUMMARY OF BACKGROUND DATA: 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. METHODS: 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. RESULTS: 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. CONCLUSION: The investigational group consistently demonstrated statistical superiority versus fusion on key clinical outcomes including improved physical function, reduced pain, and earlier return to work.

A randomized, placebo-controlled trial of intradiscal electrothermal therapy for the treatment of discogenic low back pain.

BACKGROUND: Intradiscal electrothermal therapy (IDET) is a treatment for discogenic low back pain the efficacy of which has not been rigorously tested. PURPOSE: To compare the efficacy of IDET with that of a placebo treatment. STUDY DESIGN/SETTING: Randomized, placebo-controlled, prospective trial. PATIENT SAMPLE: Patients were recruited by referral and the media. No inducements were provided to any patient in order to have them participate. Of 1,360 individuals who were prepared to submit to randomization, 260 were found potentially eligible after clinical examination and 64 became eligible after discography. All had discogenic low back pain lasting longer than 6 months, with no comorbidity. Thirty-seven were allocated to IDET and 27 to sham treatment. Both groups were satisfactorily matched for demographic and clinical features. METHODS: IDET was performed using a standard protocol, in which the posterior annulus of the painful disc was heated to 90 C. Sham therapy consisted of introducing a needle onto the disc and exposing the patient to the same visual and auditory environment as for a real procedure. Thirty-two (85%) of the patients randomized to the IDET group and 24 (89%) of those assigned to the sham group complied fully with the protocol of the study, and complete follow-up data are available for all of these patients. OUTCOME MEASURES: The principal outcome measures were pain and disability, assessed using a visual analog scale for pain, the Short Form (SF)-36, and the Oswestry disability scale. RESULTS: Patients in both groups exhibited improvements, but mean improvements in pain, disability and depression were significantly greater in the group treated with IDET. More patients deteriorated when subjected to sham treatment, whereas a greater proportion showed improvements in pain when treated with IDET. The number needed to treat, to achieve 75% relief of pain, was five. Whereas approximately 40% of the patients achieved greater than 50% relief of their pain, approximately 50% of the patients experienced no appreciable benefit. CONCLUSIONS: Nonspecific factors associated with the procedure account for a proportion of the apparent efficacy of IDET, but its efficacy cannot be attributed wholly to a placebo effect. The results of this trial cannot be generalized to patients who do not fit the strict inclusion criteria of this study, but IDET appears to provide worthwhile relief in a small proportion of strictly defined patients undergoing this treatment for intractable low back pain.