Cage technology simplified anterior cervical interbody fusion and proved efficient. The fact there was no graft harvesting saved operating time and hospital stay. STATEMENT: It is not the intention of the author to indicate material preference in this article.

BAK-C is a new autostabilizing interbody cage which is implanted during an anterior cervical procedure to provide stability to the motion segment and allow fusion to occur. Special instrumentation is provided with a bone collecting reamer. The system utilizes surgical site bone graft as the osteo-inductive material within the implant. Biomechanical testing indicates improved stability and animal studies show good fusion. The basic principle is distraction-compression using the tension forces of the annulus fibrosus. Operative material concerns a two years experience with 80 patients (101 levels), 72 with cervical radiculopathy, 8 with myelopathy. Clinical evaluation is assessed on a ten point analogue pain scale for neck and arm/shoulder pain, with neurological examination. Radiological evaluation includes dynamic X-rays, myelo-CT and MRI. Patients are re-evaluated at 1, 6, 12 months postoperatively. Results for neck and radicular pain is excellent, but neurological recovery for radiculopathy and myelopathy is quite different. Radiological results are also good with (except one case) no instability, no cage migration, no kyphosis, no pseudarthrosis. Bone fusion is assessed at 6 and 12 months. Complications are few with proper technique, mainly correct distraction, symmetrical endplate drilling and lateral X-ray control. Only one patient needed an early re-operation with additional miniplate fixation. Immediate stability with good clinical response and no graft morbidity are the advantages of this implant compared to conventional cervical interbody grafting techniques.

Cervical and lumbar interbody fusions with threaded titanium cages appear to be efficacious with few complications. Long term follow-up (4 years cervical, 7 years lumbar) confirms that impression.

OBJECT Although cervical total disc replacement (TDR) has shown equivalence or superiority to anterior cervical discectomy and fusion (ACDF), potential problems include nonphysiological motion (hypermobility), accelerated degeneration of the facet joints, particulate wear, and compromise of the mechanical integrity of the endplate during device fixation. Dynamic cervical stabilization is a novel motion-preserving concept that facilitates controlled, limited flexion and extension, but prevents axial rotation and lateral bending, thereby reducing motion across the facet joints. Shock absorption of the Dynamic Cervical Implant (DCI) device is intended to protect adjacent levels from accelerated degeneration. METHODS The authors conducted a prospective evaluation of 53 consecutive patients who underwent DCI stabilization for the treatment of 1-level (n = 42), 2-level (n = 9), and 3-level (n = 2) cervical disc disease with radiculopathy or myelopathy. Forty-seven patients (89%) completed all clinical and radiographic outcomes at a minimum of 24 months. Clinical outcomes consisted of Neck Disability Index (NDI) and visual analog scale (VAS) scores, neurological function at baseline and at latest follow-up, as well as patient satisfaction. Flexion-extension radiography was evaluated for device motion, implant migration, subsidence, and heterotopic ossification. Cervical sagittal alignment (Cobb angle), functional spinal unit (FSU) angle, and range of motion (ROM) at index and adjacent levels were evaluated with WEB 1000 software. RESULTS The NDI score, VAS neck and arm pain scores, and neurological deficits were significantly reduced at each postoperative time point compared with baseline (p < 0.0001). At 24 months postoperatively, 91% of patients were very satisfied and 9% somewhat satisfied, while 89% would definitely and 11% would probably elect to have the same surgery again. In 47 patients with 58 operated levels, the radiographic assessment showed good motion (5°–12°) of the device in 57%, reduced motion (2°–5°) in 34.5%, and little motion (0–2°) in 8.5%. The Cobb and FSU angles improved, showing a clear tendency for lordosis with the DCI. Motion greater than 2° of the treated segment could be preserved in 91.5%, while 8.5% had a near segmental fusion. Mean ROM at index levels demonstrated satisfying motion preservation with DCI. Mean ROM at upper and lower adjacent levels showed maintenance of adjacent-level kinematics. Heterotopic ossification, including 20% minor and 15% major, had no direct impact on clinical results. There were 2 endplate subsidences detected with an increased segmental lordosis. One asymptomatic anterior device migration required reoperation. Three patients underwent a secondary surgery in another segment during follow-up, twice for a new disc herniation and once for an adjacent degeneration. There was no posterior migration and no device breakage. CONCLUSIONS Preliminary results indicate that the DCI implanted using a proper surgical technique is safe and facilitates excellent clinical outcomes, maintains index-and adjacent-level ROM in the majority of cases, improves sagittal alignment, and may be suitable for patients with facet arthrosis who would otherwise not be candidates for cervical TDR. Shock absorption together with maintained motion in the DCI may protect adjacent levels from early degeneration in longer follow-up.

Two recent cases of vertebral artery injury from cervical fracture-dislocation prompted us to review the literature of these wrongly thought uncommon lesions. Extracranial vertebral artery injury during cervical trauma needs to be suspected not only in the case of vertebrobasilar ischemia, but also in asymptomatic patients presenting serious flexion-distraction deformities. Fracture of a transverse foramen or facet joint dislocation should alert the clinician. Magnetic resonance evaluates blood flow and vessel injury, usually unilateral, localized to the traumatized unstable vertebral segment. A four-stage classification is useful to understand and treat vertebral artery injury, also a standardized therapeutic protocol is not documented. Anterior cervical fusion seems indicated to decompress the injured vessel, and to avoid further damage to both vertebral arteries. Unstable spine conditions may also promote clot mobilization at the traumatized vessel leading to vertebrobasilar embolization. The benefit of antithrombotic therapy in reducing neurological morbidity and improving outcome is not yet established and needs long-term follow-up.