Robert J. Jackson, Reginald J. Davis, Gregory A. Hoffman, Hyun W. Bae, Michael S. Hisey, Kee D. Kim, Steven E. Gaede and Pierce Dalton Nunley
Cervical total disc replacement (TDR) has been shown in a number of prospective clinical studies to be a viable treatment alternative to anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic degenerative disc disease. In addition to preserving motion, evidence suggests that cervical TDR may result in a lower incidence of subsequent surgical intervention than treatment with fusion. The goal of this study was to evaluate subsequent surgery rates up to 5 years in patients treated with TDR or ACDF at 1 or 2 contiguous levels between C-3 and C-7.
This was a prospective, multicenter, randomized, unblinded clinical trial. Patients with symptomatic degenerative disc disease were enrolled to receive 1- or 2-level treatment with either TDR as the investigational device or ACDF as the control treatment. There were 260 patients in the 1-level study (179 TDR and 81 ACDF patients) and 339 patients in the 2-level study (234 TDR and 105 ACDF patients).
At 5 years, the occurrence of subsequent surgical intervention was significantly higher among ACDF patients for 1-level (TDR, 4.5% [8/179]; ACDF, 17.3% [14/81]; p = 0.0012) and 2-level (TDR, 7.3% [17/234]; ACDF, 21.0% [22/105], p = 0.0007) treatment. The TDR group demonstrated significantly fewer index- and adjacent-level subsequent surgeries in both the 1- and 2-level cohorts.
Five-year results showed treatment with cervical TDR to result in a significantly lower rate of subsequent surgical intervention than treatment with ACDF for both 1 and 2 levels of treatment.
Clinical trial registration no.: NCT00389597 (clinicaltrials.gov)
Pierce D. Nunley, Marcus B. Stone, Michael S. Hisey, Kee D. Kim, Robert J. Jackson, Hyun W. Bae, Gregory A. Hoffman, Steven E. Gaede, Guy O. Danielson III, Charles Gordon, Reginald J. Davis and Bimal Rami
Reginald J. Davis, Pierce Dalton Nunley, Kee D. Kim, Michael S. Hisey, Robert J. Jackson, Hyun W. Bae, Gregory A. Hoffman, Steven E. Gaede, Guy O. Danielson III, Charles Gordon and Marcus B. Stone
The purpose of this study was to evaluate the safety and effectiveness of 2-level total disc replacement (TDR) using a Mobi-C cervical artificial disc at 48 months' follow-up.
A prospective randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc was conducted at 24 centers in the US. Three hundred thirty patients with degenerative disc disease were randomized and treated with cervical total disc replacement (225 patients) or the control treatment, anterior cervical discectomy and fusion (ACDF) (105 patients). Patients were followed up at regular intervals for 4 years after surgery.
At 48 months, both groups demonstrated improvement in clinical outcome measures and a comparable safety profile. Data were available for 202 TDR patients and 89 ACDF patients in calculation of the primary endpoint. TDR patients had statistically significantly greater improvement than ACDF patients for the following outcome measures compared with baseline: Neck Disability Index scores, 12-Item Short Form Health Survey Physical Component Summary scores, patient satisfaction, and overall success. ACDF patients experienced higher subsequent surgery rates and displayed a higher rate of adjacent-segment degeneration as seen on radiographs. Overall, TDR patients maintained segmental range of motion through 48 months with no device failure.
Four-year results from this study continue to support TDR as a safe, effective, and statistically superior alternative to ACDF for the treatment of degenerative disc disease at 2 contiguous cervical levels.
Clinical trial registration no.: NCT00389597 (clinicaltrials.gov)
Reginald J. Davis, Kee D. Kim, Michael S. Hisey, Gregory A. Hoffman, Hyun W. Bae, Steven E. Gaede, Ralph F. Rashbaum, Pierce Dalton Nunley, Daniel L. Peterson and John K. Stokes
Cervical total disc replacement (TDR) is intended to treat neurological symptoms and neck pain associated with degeneration of intervertebral discs in the cervical spine. Anterior cervical discectomy and fusion (ACDF) has been the standard treatment for these indications since the procedure was first developed in the 1950s. While TDR has been shown to be a safe and effective alternative to ACDF for treatment of patients with degenerative disc disease (DDD) at a single level of the cervical spine, few studies have focused on the safety and efficacy of TDR for treatment of 2 levels of the cervical spine. The primary objective of this study was to rigorously compare the Mobi-C cervical artificial disc to ACDF for treatment of cervical DDD at 2 contiguous levels of the cervical spine.
This study was a prospective, randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc conducted at 24 centers in the US. The primary clinical outcome was a composite measure of study success at 24 months. The comparative control treatment was ACDF using allograft bone and an anterior plate. A total of 330 patients were enrolled, randomized, and received study surgery. All patients were diagnosed with intractable symptomatic cervical DDD at 2 contiguous levels of the cervical spine between C-3 and C-7. Patients were randomized in a 2:1 ratio (TDR patients to ACDF patients).
A total of 225 patients received the Mobi-C TDR device and 105 patients received ACDF. At 24 months only 3.0% of patients were lost to follow-up. On average, patients in both groups showed significant improvements in Neck Disability Index (NDI) score, visual analog scale (VAS) neck pain score, and VAS arm pain score from preoperative baseline to each time point. However, the TDR patients experienced significantly greater improvement than ACDF patients in NDI score at all time points and significantly greater improvement in VAS neck pain score at 6 weeks, and at 3, 6, and 12 months postoperatively. On average, patients in the TDR group also maintained preoperative segmental range of motion at both treated segments immediately postoperatively and throughout the study period of 24 months. The reoperation rate was significantly higher in the ACDF group at 11.4% compared with 3.1% for the TDR group. Furthermore, at 24 months TDR demonstrated statistical superiority over ACDF based on overall study success rates.
The results of this study represent the first available Level I clinical evidence in support of cervical arthroplasty at 2 contiguous levels of the cervical spine using the Mobi-C cervical artificial disc. These results continue to support the use of cervical arthroplasty in general, but specifically demonstrate the advantages of 2-level arthroplasty over 2-level ACDF. Clinical trial registration no.: NCT00389597 (ClinicalTrials.gov).
Kathryn L. Holloway, Steven E. Gaede, Philip A. Starr, Joshua M. Rosenow, Viswanathan Ramakrishnan and Jaimie M. Henderson
Functional neurosurgical interventions such as deep brain stimulation (DBS) are traditionally performed with the aid of a stereotactic frame. Although frameless techniques have been perceived as less accurate, data from a recent phantom study of a modified frameless approach demonstrated a laboratory accuracy exceeding that obtained using a common frame system. The present study was conducted to evaluate the accuracy of a frameless system in routine clinical use.
Deep brain stimulation leads were implanted in 38 patients by using a skull-mounted trajectory guide and an image-guided workstation. Registration was accomplished with bone fiducial markers. Final lead positions were measured on postoperative computerized tomography scans and compared with the planned lead positions. The accuracy of the Leksell frame within the clinical situation has been reported on in a recent study; these raw data served as a comparison data set.
The difference between expected and actual lead locations in the x plane was 1.4 mm in the frame-based procedure and 1.6 mm in the frameless procedure. Similarly, the difference in the y plane was 1.6 mm in the frame-based system and 1.3 mm in the frameless one. The error was greatest in the z plane, that is, 1.7 mm in the frame-based method and 2 mm in the frameless system. Multivariate analysis of variance demonstrated no statistically significant difference in the accuracy of the two methods.
The accuracy of the frame-based and frameless systems was not statistically significantly different (p = 0.22). Note, however, that frameless techniques offer advantages in patient comfort, separation of imaging from surgery, and decreased operating time.
David G. Malone, Nevan G. Baldwin, Frank J. Tomecek, Christopher M. Boxell, Steven E. Gaede, Christopher G. Covington and Kenyon K. Kugler
The authors report a series of 22 patients in whom major complications developed after cervical spinal manipulation therapy (CSMT). A second objective was to estimate the regional incidence of these complications and to compare it with the very low incidences reported in the literature.
During a 5-year period, practioners at a single group neurosurgical practice in Tulsa, Oklahoma, treated 22 patients, who were markedly worse during, or immediately after, CSMT. The details of these cases are reported. The 1995 US Government National Census was used to define the regional referral population for Tulsa. The published data regarding the incidence of serious CSMT-related complications and the rate of CSMTs undertaken nationally were used to estimate the expected number of CSMT-related complications in the authors' region. The number (22 cases) reported in this series was used to estimate the actual regional incidence.
Complications in the series included radiculopathy (21 cases), myelopathy (11 cases), Brown–Séquard syndrome (two cases), and vertebral artery (VA) occlusion (one case). Twenty-one patients underwent surgery. Poor outcomes were observed in three, outcome was unchanged in one, and 17 improved. The number of patients in this series exceeded the expected number for the region.
Cervical spinal manipulation therapy may worsen preexisting cervical disc herniation or cause disc herniation resulting in radiculopathy, myelopathy, or VA compression. In cases of cervical spondylosis, CSMT may also worsen preexisting myelopathy or radiculopathy. Manipulation of the cervical spine may also be associated with higher complication rates than previously reported.