Scott L. Blumenthal

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

Study Design. A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial. Objectives. The purpose of this study was to compare the safety and effectiveness of lumbar total disc replacement, using the CHARITÉ™ 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. Summary of Background Data. Reported results of lumbar total disc replacement have been favorable, but studies have been limited to retrospective case series and/or small sample sizes. Methods. 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 CHARITÉ™ 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. Results. Patients in both groups improved significantly following surgery. Patients in the CHARITÉ™ artificial disc group recovered faster than patients in the control group. Patients in the CHARITÉ™ artificial discgroup 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 CHARITÉ™ 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 CHARITÉ™ artificial disc group (P < 0.05). The complication rate was similar between both groups. Conclusions. This prospective, randomized, multicenter study demonstrated that quantitative clinical outcome measures following lumbar total disc replacement with the CHARITÉ™ 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 CHARITÉ™ artificial disc is a safe and effective alternative to fusion for the surgical treatment of symptomatic disc degeneration in properly indicated patients. The CHARITÉ™ 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.

The role of anterior lumbar fusion for internal disc disruption.

Internal disc disruption is a syndrome of traumatically induced low-back pain arising from the intervertebral disc. The diagnosis is confirmed by abnormal discography with concordant pain reproduction at the affected level or levels. Thirty-four patients with internal disc disruption at one level were followed for an average of 29 months. Eighteen (53%) underwent anterior lumbar fusion at the L4–5 disc, 11 (32%) at the L5-S1 disc and the remainder at the L3–4 or L2–3 disc. Bank bone was used in all but seven patients for interbody fusion. Treatment was Judged a success by the patient returning to work or normal activities and requiring either no medications or an anti-inflammatory drug only. By the above criteria 25 patients (74%) had successful outcome of treatment. The average time to return to work or normal activities was 6.1 months. The overall union rate was 73% with an average time to union of approximately 12 months. Complications consisted of graft extrusion requiring revision and retrograde ejaculation. These occurred in one patient and were the only complications in the series. We concluded that disc excision and anterior interbody fusion is an effective treatment for internal disc disruption.

Revisability of the CHARITE artificial disc replacement: analysis of 688 patients enrolled in the U.S. IDE study of the CHARITE Artificial Disc.

Study Design. A prospective, randomized, multicenter, FDA-regulated Investigational Device Exemption clinical trial. Objectives. To analyze the incidence of, and reasons for, reoperation in all patients (treatment and control) enrolled in the IDE study. Summary of Background Data. This is the first report of the incidence and nature of reoperations following lumbar TDR as part of a controlled, prospective, multicenter trial. Methods. A total of 688 patients meeting the inclusion and exclusion criteria were enrolled in one of three arms of the study at 14 centers across the United States. This cohort includes 71 nonrandomized cases, 205 randomized cases, and 313 continued access cases, all receiving the CHARITÉ Artificial Disc, as well as 99 randomized cases in the control group (ALIF with threaded fusion cages and autograft). A detailed analysis was performed of clinical chart notes, operative notes, and adverse event reports for all patients requiring reoperation following their index surgery. Results. Of the 589 patients with TDR, 52 (8.8%) required reoperation. Of the 99 patients with lumbar fusion, 10 (10.1%) required reoperation, and an additional 2 required surgery for adjacent level disease (P = 0.7401). There were 24 TDR patients who underwent a repeated anterior retroperitoneal approach, with 22 (91.7%) having had a successful removal of the prosthesis. Seven of the 24 TDR prostheses requiring removal were revised to another CHARITÉ Artificial Disc. The mean time to reoperation in all patients was 9.7 months. A total of 29 patients (4.9%) in the TDR group required posterior instrumentation and fusion as did 10 (10.1%) in the control group (P = 0.0562). At 2 years or more follow-up, 93.9%(553/589 = 93.9%) of patients receiving TDR with the CHARITÉ Artificial Disc had a successfully functioning prosthesis with a mean of over 7° of flexion-extension mobility. Conclusions. Lumbar TDR with the CHARITÉ Artificial Disc did not preclude any further procedures at the index level during primary insertion, with nearly one third being revisable to a new motion-preserving prosthesis and just over two thirds being successfully converted to ALIF and/ or posterior pedicle screw arthrodesis, the original alternative procedure.

Artificial disc: preliminary results of a prospective study in the United States

Abstract. Artificial discs have been used in Europe for many years with good results. This technology has recently been available in the United States on a limited, investigational basis. The purpose of this study is to review the preliminary results of one centers experience using the SB Charité III disc replacement. The study group consisted of the series of our first consecutive 56 patients who received the Link SB Charité III artificial disc. There were 25 men and 31 women, with a mean age of 39.9 years. All patients had single-level symptomatic disc disruption at L4-5 or L5-S1. The discs were implanted using the same approach as used for mini-open anterior lumbar interbody fusion procedures. The primary data recorded included visual analog scales (VAS) assessing pain and the Oswestry Disability Questionnaire. Data were collected pre-operatively and at 6 weeks, 3 months, 6 months, and 12 months post-operatively. Peri-operative data as well as complications were recorded. At the time of this preliminary study, 22 patients have reached the 12-month post-operative follow-up period. There was a significant improvement in the VAS and Oswestry scores at the 6-week follow-up period. These improvements were maintained throughout the 12-month follow-up period. The preliminary results of this prospective study indicate that the artificial disc yields significant improvement that is maintained during a 12-month follow-up. Data from more patients and with longer follow-up are needed to determine whether these results can be maintained in the long term.

Functional results after anterior lumbar fusion at L5-S1 in patients with normal and abnormal MRI scans

The debate continues as to which patient responds best to surgical versus nonsurgical intervention for painful degenerative disc syndrome. Discography is often used as the basis for that decision. In a review of 53 cases followed for an average of 20 months after surgery, only 50% of patients with type I (contained) discography and normal magnetic resonance imaging findings were found to be improved. In those patients with types II and III (noncontained) discography and abnormal magnetic resonance imaging scans, a 75% success rate was seen. There was an overall 80% fusion rate for all patients who underwent anterior lumbar fusion at L5-S1. Average age was 34 years, with average length of disability from low-back pain of 11 months. All patients were placed in a similar presurgery and postsurgery rehabilitation protocol and had failed nonsurgial treatment options. In this matched group of patients, those with abnormal magnetic resonance imaging scans and abnormal discography, clearly fared better, with a 75% percent success rate versus 50% success rate in those with normal magnetic resonance imaging findings. This series raises the question as to whether those patients with normal magnetic resonance imaging findings are surgical candidates.

Lumbar Scheuermann's: A Clinical Series and Classification

Scheuermanns disease of the thoracic spine is a well-defined entity, although its exact etiology is unknown. In the thoracolumbar or lumbar spine however, the criteria are much less strict for the application of this eponym. A retrospective review of all the cases of lumbar Scheuermanns disease seen at the Texas Scottish Rite Hospital revealed two distinct radiographic pictures. These consisted of a “classic” Scheurermanns and an “atypical” type characterized by vertebral end plate changes, disc space narrowing, and anterior Schmorls nodes, but not otherwise fulfilling Sorensons criteria. This group tended to occur in more athletic adolescents or those with a history of increased axial stress to the spine. A subgrouping of atypical Scheuermanns disease is proposed and includes acute traumatic intraosseous disc herniation. Based on these findings, a classification of lumbar Scheuermanns disease is proposed.

Complications of the Wiltse Pedicle Screw Fixation System.

The purpose of the current study is to retrospectively review the incidence and types of complications occurring using a single pedicle screw fixation system for lumbar spine fusions. For a 3-year period beginning in July 1987, 470 patients underwent spinal fusion and instrumentation with the Wiltse Pedicle Screw Fixation System. Although multiple configurations of the Wiltse System were included, the predominant construct was that of segmental pedicle screw fixation. Complications occurred in a total of 29 patients, for an overall complication rate of 6%. Among the complications were 10 wound problems (2%) that included 2 seromas requiring drainage and 3 superficial wound infections. The remaining five wound complications were deep wound infections requiring irrigation and debridement. The overall deep wound infection rate was 1%. Neurologic complications occurred in two patients, one with temporary foot drop and one with persistent L5 nerve root irritation confirmed by electromyogram (EMG). Both of these patients underwent anatomic workup, which failed to reveal any evidence of impingement by either screw or other hard tissue. Two intraoperative complications occurred, both involving fracture of the L5 pedicle. No adverse sequela resulted. There were 15 hardware complications, for an overall rate of 3%. This included four patients with broken screws (a total of eight screws). There were three failures at the screw-bone interface, as well as four patients with uncoupling of the screw rod linkage. In addition, there were four broken rods encountered. A total of 122 Wiltse devices were removed, for an overall removal rate of 25%.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of surgical volume and the early experience with lumbar total disc replacement as part of the investigational device exemption study of the Charité Artificial Disc.

Study Design. A prospective, randomized, multicenter, Food and Drug Administration regulated Investigational Device Exemption (IDE) clinical trial. Objectives. To discern whether there is a correlation between surgical volume and clinical outcomes, as well as the complication rate and perioperative data points, for lumbar total disc replacement. To examine the early experience for lumbar total disc replacement as part of an IDE study. Summary of Background Data. To our knowledge, an analysis of the effect of surgical volume has not been performed for any spine surgical procedure. Prior reports of the early experience with lumbar total disc replacement consist of retrospective reviews with nonspecific indications. Methods. An analysis was performed of the Food and Drug Administration IDE Study of the Charité Artificial Disc (DePuy Spine, Inc., Raynham, MA). Patients enrolled in the control group were omitted from the analysis. Up to 5 nonrandomized cases (representing the early experience) were performed at each site before beginning the randomized arm of the study. There were 3 comparisons performed: nonrandomized cases (71) versus randomized cases (205); randomized cases performed by high-enrolling surgeons versus low-enrolling surgeons; and randomized cases at high-volume institutions versus low-volume institutions. Results. The high-enrolling groups had a significantly lower mean hospital stay and operating time compared to the low-enrolling groups (P < 0.05). High-enrolling surgeons and institutions showed significantly shorter operating times, length of hospital stay, and complication rates. High-enrolling surgeons had significantly fewer device failures and cases of neurologic deterioration. Mean operating time and hospital stay were significantly lower in the randomized group (P < 0.05) compared to the nonrandomized group. Blood loss and approach-related complications were similar between the 2 groups. Device failure requiring removal was 4.2% in the nonrandomized group and 1.5% in the randomized group. Conclusions. Surgeons and institutions with a high volume of lumbar total disc replacement cases have a reduction in key perioperative and postoperative parameters that provide a clinical and/or economic benefit. Surgeons may expect longer hospital stays, higher blood loss, and a higher rate of certain complications in their early experience with total disc replacement procedures, but there was no effect on clinical outcomes.

Distribution of in vivo and in vitro range of motion following 1-level arthroplasty with the CHARITÉ artificial disc compared with fusion

OBJECT One of the goals of lumbar arthroplasty is to restore and maintain range of motion (ROM) and to protect adjacent levels from abnormal motion, which may be a factor in transition syndrome following arthrodesis. In this study, in vitro ROM results were compared with in vivo, 2-year postoperative radiographic ROM evaluations. METHODS Radiographs of patients enrolled in the CHARITE investigational device exemption study were analyzed at baseline and at 2 years postoperatively. The ROM in flexion/extension at the implanted and adjacent levels was measured, normalized, and compared with ROM results obtained using cadaver (in vitro) evaluations. RESULTS Preoperative ROM distributions in patients enrolled for arthroplasty or fusion at the L4-5 level was as follows: 28% motion was observed at L3-4, 35% at L4-5 and 37% at L5-S1. Following a one-level arthroplasty at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 36% at L3-4, 30% at L4-5 and 35% at L5-S1. Following a one-level fusion with BAK and pedicle screws at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 45% at L3-4, 9% at L4-5 and 46% at L5-S1. CONCLUSIONS The baseline as well as the 2-year in vivo data confirmed previously published in vitro data. One-level arthroplasty was shown herein to replicate the normal distribution of motion of the intact spine.

Prospective study evaluating total disc replacement: Preliminary results

For many years, there has been an interest in disc replacements. There are a few retrospective studies from Europe reporting promising results for these devices. The purpose of this study is to review the preliminary results of the SB Charité disc replacement device in a prospective study. The study group consists of a consecutive series of our first 57 patients who received the Link SB Charité device implanted through a mini–open anterior approach. The primary clinical indications for disc replacement were single-level symptomatic disc disease at L4–L5 or L5–S1 and no significant facet joint changes. The outcome data include the Visual Analog Scale (VAS) assessing pain intensity and the Oswestry Low Back Pain Disability Questionnaire. Data were collected prior to surgery and at 6 weeks, 3 months, 6 months, and 12 months after surgery. Twenty-four-month follow-up data are currently being collected. The mean VAS score improved 50.8% by the 6-week follow-up, and significant improvement was maintained throughout follow-up. The mean Oswestry score improved 38.7% at the 6-week follow-up, and further slight improvement was noted during the later follow-up periods. This study found that significant improvements were achieved by the 6-week postoperative visit in the pain and disability scores following disc replacement surgery. Significant improvement was maintained through the 12-month follow-up visit. Although these preliminary results are encouraging, long-term follow-up and a greater number of patients are needed to further evaluate the outcome of these devices.