Use of spinous processes to determine the optimal trajectory for placement of lateral mass screws: technical note.

STUDY DESIGN: Retrospective chart analysis. OBJECTIVE: In the current report, we present a new technique for the placement of lateral mass screws from C3 to C7. The safety, complications, and long-term clinical and imaging follow-up were analyzed. To address potential risk factors for this technique, relevant literature was reviewed and discussed herein. SUMMARY OF BACKGROUND DATA: Multiple techniques have been reported to place lateral mass screws in the subaxial cervical spine. The trajectory used aims to avoid the vertebral artery and the exiting nerve root. Because of inherent differences in determining the screw trajectory for placement, there can be considerable differences among surgeons. METHODS: A retrospective analysis of our experience over the period from 2003 to 2006 was undertaken. Standard practices for obtaining institutional review board approval were followed. Radiographs, hospital records, and office charts of 34 patients were reviewed. There was an equal distribution between males and females and the mean age was 56.3 years. Pain was the most frequent presentation. The indications for posterior instrumentation included instability secondary to pseudoarthrosis, infection, spondylosis, osseous metastasis, trauma, and iatrogenic etiologies. RESULTS: The follow-up period ranged from 1 to 30 months (average 9.1 mo). Postoperative complications included wound infection (3 cases), malpositioned screw (1 case), cerebrospinal fluid leak (1 case), and dislodged rod (1 case). There were no mortalities directly related to the procedure. CONCLUSIONS: This technique for placement of lateral mass screws yielded adequate fixation without any appreciable neurovascular complications. It provides a useful alternative for screw placement in patients with intact spinous processes.

Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: five-year follow-up.

BACKGROUND CONTEXT: The CHARITE artificial disc, a lumbar spinal arthroplasty device, was approved by the United States Food and Drug Administration in 2004 based on two-year safety and effectiveness data from a multicenter, prospective, randomized investigational device exemption (IDE) study. No long-term, randomized, prospective study on the CHARITE disc or any other artificial disc has been published to date. PURPOSE: The purpose of this study was to compare the safety and effectiveness at the five-year follow-up time point of lumbar total disc replacement using the CHARITE artificial disc (DePuy Spine, Raynham, MA) with that of anterior lumbar interbody fusion (ALIF) with BAK cages and iliac crest autograft, for the treatment of single-level degenerative disc disease from L4 to S1, unresponsive to nonoperative treatment. STUDY DESIGN/SETTING: Randomized controlled trial-five-year follow-up. PATIENT SAMPLE: Ninety CHARITE patients and 43 BAK patients. OUTCOME MEASURES: Self-reported measures: visual analog scale (VAS); validated Oswestry disability index (ODI version 1.0); Short-Form 36 Questionnaire, and patient satisfaction. Physiologic measures: radiographic range of motion, disc height, and segmental translation. Functional measures: work status. METHODS: Of the 375 subjects enrolled in the CHARITE IDE trial, 277 were eligible for the five-year study and 160 patients thereof completed the five-year follow-up. The completers included 133 randomized patients. Overall success was defined as improvement> or =15 pts in ODI vs. baseline, no device failure, absence of major complications, and maintenance or improvement of neurological status. Additional clinical outcomes included an ODI questionnaire as well as VAS, SF-36, and patient satisfaction surveys. Work status was tracked for all patients. Safety assessments included occurrence and severity of adverse events and device failures. Radiographic analyses such as index- and adjacent-level range of motion, segmental translation, disc height, and longitudinal ossification were also carried out. RESULTS: Overall success was 57.8% in the CHARITE group vs. 51.2% in the BAK group (Blackwelder's test: p=0.0359, Delta=0.10). In addition, mean changes from baseline for ODI (CHARITE: -24.0 pts vs. BAK: -27.5 pts), VAS pain scores (CHARITE: -38.7 vs. BAK: -40.0), and SF-36 questionnaires (SF-36 Physical Component Scores [PCS]: CHARITE: 12.6 pts vs. BAK: 12.3 pts) were similar across groups. In patient satisfaction surveys, 78% of CHARITE patients were satisfied vs. 72% of BAK patients. A total of 65.6% patients in the CHARITE group vs. 46.5% patients in the BAK group were employed full-time. This difference was statistically significant (p=0.0403). Long-term disability was recorded for 8.0% of CHARITE patients and 20.9% of BAK patients, a difference that was also statistically significant (p=0.0441). Additional index-level surgery was performed in 7.7% of CHARITE patients and 16.3% of BAK patients. Radiographic findings included operative and adjacent-level range of motion (ROM), intervertebral disc height and segmental translation. At the five-year follow-up, the mean ROM at the index level was 6.0 degrees for CHARITE patients and 1.0 degrees for BAK patients. Changes in disc height were also similar for both CHARITE and BAK patients (0.7 mm for both groups, p=0.9827). Segmental translation was 0.4 and 0.8mm in patients implanted with CHARITE at L4-L5 vs. L5-S1, respectively, and 0.1mm in BAK patients. CONCLUSIONS: The results of this five-year, prospective, randomized multicenter study are consistent with the two-year reports of noninferiority of CHARITE artificial disc vs. ALIF with BAK and iliac crest autograft. No statistical differences were found in clinical outcomes between groups. In addition, CHARITE patients reached a statistically greater rate of part- and full-time employment and a statistically lower rate of long-term disability, compared with BAK patients. Radiographically, the ROMs at index- and adjacent levels were not statistically different from those observed at two-years postsurgery.

Prospective, Randomized, Multicenter FDA IDE Study of CHARITÉ Artificial Disc versus Lumbar Fusion: Effect at 5-year Follow-up of Prior Surgery and Prior Discectomy on Clinical Outcomes Following Lumbar Arthroplasty.

BACKGROUND: Candidates for spinal arthrodesis or arthroplasty often present with a history of prior surgery such as laminectomy, laminotomy or discectomy. In this study, lumbar arthroplasty patients with prior surgery, and in particular patients with prior discectomy, were evaluated for their clinical outcomes at the 5-year time point. METHODS: Randomized patients from the 5-year CHARITÉ investigational device exemption (IDE) study were divided as follows: 1) fusion prior surgery (excluding prior decompression with fusion) group (FSG); 2) fusion prior discectomy group (FDG); 3) fusion no prior surgery group (FNG); 4) arthroplasty prior surgery group (ASG); 5) arthroplasty prior discectomy group (ADG); and 6) arthroplasty no prior surgery group (ANG). The 5-year clinical outcomes included visual analog scale (VAS), Oswestry Disability Index 2.0 (ODI), patient satisfaction, and work status. RESULTS: In the arthroplasty group, all subgroups had statistically significant VAS improvements from baseline (VAS change from baseline: ASG = -36.6 ± 29.6, P < 0.0001; ADG = -40.2 ± 30.9, P = 0.0002; ANG = -36.5 ± 34.6, P < 0.0001). There was no statistical difference between subgroups (P = 0.5587). In the fusion group, VAS changes from baseline were statistically significant for the FNG and FSG subgroups, but not for the FDG patients (FNG = -46.3 ± 28.8, P < 0.0001; FSG = -24.2 ± 36.4, P = 0.0444; FDG = -26.7 ± 38.7, P = 0.2188). A trend of decreased VAS improvements was observed for FSG versus FNG (P = 0.0703) subgroups. Similar findings and trends were observed in ODI scores (Changes in ODI from baseline: ASG = -20.4 ± 23.8, P < 0.0001; ANG = -26.6±21.1, P < 0.0001; ADG= -17.6 ± 28.6, P = 0.0116; FSG = -14.5 ± 21.2, P = 0.0303; FNG= -32.5 ± 22.6, P < 0.0001; FDG = -10.7 ± 9.4, P = 0.0938). The greatest improvement in work status from preoperative to postoperative was seen in the ADG subgroup (28% increase in part- and full-time employment), while the FDG subgroup showed the greatest reduction in work status (17% decrease). CONCLUSIONS: Arthroplasty patients with prior surgery or prior discectomy had similar clinical outcomes as arthroplasty patients without prior surgery, while fusion patients with prior surgery or prior discectomy showed trends of lowered clinical outcomes compared to fusion patients without prior surgery or discectomy.

Complications of Lumbar Artificial Disc Replacement Compared to Fusion: Results From the Prospective, Randomized, Multicenter US Food and Drug Administration Investigational Device Exemption Study of the Charité Artificial Disc.

BACKGROUND: Previous reports of lumbar total disc replacement (TDR) have described significant complications. The US Food and Drug Administration (FDA) investigational device exemption (IDE) study of the Charité artificial disc represents the first level I data comparison of TDR to fusion. METHODS: In the prospective, randomized, multicenter IDE study, patients were randomized in a 2:1 ratio, with 205 patients in the Charité group and 99 patients in the control group (anterior lumbar interbody fusion [ALIF] with BAK cages). Inclusion criteria included confirmed single-level degenerative disc disease at L4-5 or L5-S1 and failure of nonoperative treatment for at least 6 months. Complications were reported throughout the study. RESULTS: The rate of approach-related complications was 9.8% in the investigational group and 10.1% in the control group. The rate of major neurological complications was similar between the 2 groups (investigational = 4.4%, control = 4.0%). There was a higher rate of superficial wound infection in the investigational group but no deep wound infections in either group. Pseudarthrosis occurred in 9.1% of control group patients. The rate of subsidence in the investigational group was 3.4%. The reoperation rate was 5.4% in the investigational group and 9.1% in the control group. CONCLUSIONS: The incidence of perioperative and postoperative complications for lumbar TDR was similar to that of ALIF. Vigilance is necessary with respect to patient indications, training, and correct surgical technique to maintain TDR complications at the levels experienced in the IDE study.

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 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. 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 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. RESULTS: 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. CONCLUSIONS: 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.

Preliminary outcomes and efficacy of the first 360 consecutive kyphoplasties for the treatment of painful osteoporotic vertebral compression fractures.

BACKGROUND CONTEXT: Osteoporosis is a major cause of morbidity in worldwide elderly populations. Patients may become susceptible to vertebral compression fractures (VCFs) from low-impact situations. For patients who have failed conventional, palliative medical therapy, kyphoplasty not only reduces pain associated with vertebral fractures, but also offers a minimally invasive procedure with the potential to address fracture reduction and spinal sagittal alignment. Kyphoplasty involves expanding an inflatable balloon tamp to create a cavity within a vertebral body before cement deposition. PURPOSE: To evaluate the safety and efficacy of kyphoplasty to reduce and fix painful osteoporotic VCFs. STUDY DESIGN/SETTING: A retrospective, single-arm cohort study of consecutive kyphoplasty patients treated at a single center. PATIENT SAMPLE: Three hundred sixty VCFs were treated during 254 kyphoplasty procedures on 222 osteoporotic patients (mean age, 76 years [range, 28-98]; 28% male and 72% female). OUTCOME MEASURES: Patient-reported pain ratings were examined. Cement extravasation was monitored by intraoperative fluoroscopy and on postoperative radiographs. Anterior and midline vertebral height were assessed from standing, lateral radiographs obtained preoperatively and postoperatively. The number of patients who returned with symptomatic, new fractures was monitored. Perioperative complications were recorded. Mean follow-up occurred 21 months after kyphoplasty (range, 6 months through 36 months). RESULTS: Immediate pain relief was reported by 89% of patients by the first follow-up visit. One patient experienced postoperative pain as a result of radiculopathy related to bone filler leakage into the foramen. The remaining patients had persistent pain and were diagnosed with either a new fracture or underlying degenerative disc disease. Greater than or equal to 20% restoration of lost vertebral height (anterior) was observed in 63% of fractures with an overall mean restoration of 30%, and > or = 20% restoration of lost vertebral height (midline) was detected in 69% of fractures with an overall mean restoration of 50%. In this cohort, 12% (30/254) of the patients required additional kyphoplasty procedures to treat 36 symptomatic, new adjacent and remote fractures. No device-related complications occurred. CONCLUSIONS: Kyphoplasty is a safe and effective, minimally invasive procedure for relief of pain associated with VCF. In our series we also demonstrated some restoration of vertebral height and partial correction of sagittal alignment.

The efficacy of anterior spine exposure by an orthopedic surgeon.

This retrospective study was designed to document the incidence and types of perioperative complications that occurred with anterior spinal fusion surgery performed solely by an orthopedic spine surgeon. This study is contrasted to previous studies that document complications from anterior approaches performed by an orthopedic surgeon with the assistance of a general or a vascular surgeon. Specifically, the procedures included thoracotomies, thoracolumbar retroperitoneal, and lumbosacral approaches. Our sample consisted of 450 patients who underwent anterior spinal fusion between levels T1 and S1, from 1985 to 1997. Patient and surgery characteristics included age, sex, diagnosis, levels of fusion, blood loss, operative time, hospitalization time, complications, American Society of Anesthesiologists state, assessment of risk factors, previous surgery, and surgical approach used. Average follow-up was 41.69 months, with a minimum of 12 months and a maximum of 132 months. Our results indicated that anterior procedures performed solely by our senior orthopedic surgeon had a lower incidence of complications, less blood loss, and shorter operative time than anterior procedures performed by an orthopedic surgeon and a vascular or a general surgeon. Our findings suggest that the anterior spinal exposure is a safe approach that may be performed solely by a spinal surgeon who is knowledgeable and experienced.

Do autologous growth factors enhance transforaminal lumbar interbody fusion?

Pseudarthrosis remains a significant problem in spinal fusion. The objective of our study was to investigate the effects of autologous growth factors (AGF) in instrumented transforaminal lumbar interbody spinal fusion (TLIF). A prospective review was carried out of 23 patients who underwent TLIF with application of AGF, with a minimum 2-year follow-up. Comparison with our historical cohort (without AGF application) was performed. Mean age at surgery was 44.3 years in the AGF treatment group. Twelve had a positive smoking history. Fourteen had undergone previous spinal surgeries. Thirteen received one-level fusions and ten received two-level fusions. The radiographic results showed a fusion rate of 100% in one-level fusions and 90% in two-level fusions. There was no significant difference in pseudarthrosis rates between the AGF treatment group and historical cohort. Excluding the cases with pseudarthrosis, there was faster bony healing in patients who had been treated with AGF application. This study indicates that although AGF may demonstrate faster fusions, it does not result in an overall increase in spinal fusion rates. Further studies are needed before AGF can routinely be used as an adjunct in spinal fusion.

Complications of multilevel cervical corpectomies and reconstruction with titanium cages and anterior plating.

The ideal surgical treatment of multilevel cervical spondylosis remains unclear. This study analyzed the complications in using titanium cages and plating to reconstruct multilevel cervical corpectomies. This was a retrospective analysis of 21 consecutive patients who had multilevel cervical corpectomies and reconstruction with titanium cages and anterior plating. Sixteen had 2-level, one had 2.5-level, three had 3-level, and one had 3.5-level corpectomies. All had reconstruction with titanium cages and anterior plating. Thirty-three percent of the patients developed complications. Radiographs revealed bony consolidation in 95% of patients. Reconstructing multilevel cervical corpectomies with titanium cages and plating is associated with complications. Advantages include rigid immobilization and the avoidance of iliac crest bone graft harvesting. Major complications are largely the result of failures of the cage and plate construct, especially in patients with osteopenic bone. Supplemental posterior stabilization may be considered for cases with spasticity or greater than 2-level corpectomies with profound osteoporosis.

Selection of fusion levels in scoliosis surgery.

Fusion levels are selected with the goal of having a balanced physiologic spine on the postoperative films. We have proposed an algorithm for selecting fusion levels based on the King-Moe scoliosis classification scheme and the flexibility of a compensatory curve. We propose the acronym TEAMS as a pneumonic. Curve type defines the region of the spine to be fused. The ends of the Cobb measurement around the region are the temporary endpoints. The endpoints are extended to avoid an apex due to the sagittal or frontal planes. The mobile disc is defined at the caudal end of the fusion area. Finally, the bending films, traction films, or intraoperative films are used to define the stable zone of Harrington that must contain the ends of the fusion mass. This scheme yields a simple, easily taught algorithm that results in reproducible endpoints for scoliosis fusion.

Better treatment of vertebral osteomyelitis using posterior stabilization and titanium mesh cages.

There is no scientific consensus on the role of posterior instrumentation in vertebral osteomyelitis. No study has examined the use of titanium cages to reconstruct the anterior column of the spine with vertebral osteomyelitis. Here the authors evaluated the efficacy of using titanium mesh cages anteriorly and posterior instrumentation after anterior debridement in the surgical treatment of vertebral osteomyelitis. In one center, 21 consecutive patients had surgery for vertebral osteomyelitis. The mean follow-up time was 67 months (range, 24 to 120 months). Ten patients received supplemental posterior instrumentation. Five patients had reconstruction of the anterior column with titanium cages. Greater improvement in sagittal alignment was noted for patients with cages implanted (p = 0.0009) and for those with posterior instrumentation (p = 0.005). Patients who received cages had greater (p = 0.0006) correction of their coronal alignment than did those patients without cages. A trend toward fewer postoperative complications emerged for patients who had posterior stabilization or titanium cages. These results support the use of posterior stabilization and titanium cages in the surgical treatment of vertebral osteomyelitis.