Object. The purposes of bone substitutes for anterior cervical fusion (ACF) are immediate biomechanical support and osteointegration of the graft. The authors report their preliminary results in performing ACF in which carbon fiber cages (CFCs) containing coralline hydroxyapatite (HA) are used as bone substitute. Methods. During a 24-month period, anterior microsurgical discectomy was performed in 45 consecutive patients for soft-disc cervical herniation. In all cases ACF was performed using a CFC containing a core of granulated coralline HA. Fifty-seven CFCs were implanted in 33 single-level and 12 two-level procedures. The mean operative time was 83 minutes for one-level and 97 minutes for two-level procedures. The mean hospital stay was 1.51 days, and there were no permanent complications. At a mean follow up of 22.3 months, the pain had decreased or disappeared in all patients, and the patients' satisfaction rate was very high. Good results were also obtained in patients who smoked cigarettes. Patients underwent radiographic evaluation at Day 1, and 1, 3, 6, and 12 months postoperatively. Implant-related complications were not observed and revision surgeries were not performed. Twelve-month cervical x-ray films demonstrated complete fusion in all cases, without evidence of breakage, collapse, pseudarthrosis, subsidence, angular deformity, or protrusion. Signs of pathological absorption and necrosis were not found in contiguous vertebral bodies, and inflammatory reactions were never seen around cages. Conclusions. These preliminary results suggest that implants composed of CFC containing granulated coralline HA are promising bone substitutes to be used in ACF, with a good rate of incorporation and no significant complications.

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BackgroundDisc arthroplasty is gaining popularity for treatment of low-back pain caused by degenerative disc disease (DDD). It can involve total disc replacement or partial disc or nucleus replacement (or augmentation). Compared with total disc replacement, nucleus replacement is less invasive, has less surgical risk, has faster postoperative recovery, and doesn't “burn bridges” should further surgery be required. However, nucleus replacement has a high risk of implant expulsion because the device is not fixed to the vertebrae. Nubac is the first polyetheretherketone (PEEK)-on-PEEK articulated disc arthroplasty device designed to optimally restore the lumbar anatomy and biomechanics.MethodsISO 10993 standards were used to evaluate the biocompatibility of the PEEK material. Chemical and thermal–mechanical tests and in vivo study assessed PEEK's biostability after exposure to high g irradiation and harsh oxidative conditions. Biomechanical tests to evaluate kinematic properties and anatomical restoration of the implanted lumbar motion segments and implant expulsion risk assessments were performed with a human cadaveric model. Because of the novelty of PEEK-on-PEEK as a self-mating articulating material, extensive wear tests were conducted with unidirectional and coupled motions. Static and fatigue strength also were tested. Animal study with a baboon model was conducted with gross, radiographic, biomechanical, and histological evaluations at 6 and 12 months postoperatively. Preliminary clinical data were collected through a prospective multicenter cohort study.ResultsPEEK demonstrated exceptional biocompatibility and biodurability. Nubac restored disc height and motion segment range of motion. The unique articulating design of the Nubac demonstrated low risk of implant expulsion in a human cadaveric model. Wear tests showed that the Nubac has minimal wear and compares favorably to other disc arthroplasty materials. The Nubac also had excellent static and fatigue properties for the intended application. The animal study showed that the Nubac caused no adverse local or systematic tissue reaction and there was no detectable wear debris. The preliminary clinical data showed no major intraoperative vascular and neurological complications. There was significant Visual Analog Scale and Oswestry Disability Index score improvement.ConclusionsThe preclinical data supported the design rationale, and the preliminary clinical data (level II evidence) on safety and efficacy were encouraging.Clinical RelevanceThe Nubac could be a viable first surgical option for patients with back pain caused by DDD.

We report a case of V ventricular cystic dilatation, presenting with specific neurological symptoms including low back pain, bilateral sciatica, weakness of dorsiflexion, and urinary retention. MRI showed a large cystic dilatation of the ventriculus terminalis. Surgical fenestration of the cyst allowed complete relief from symptoms and remission of the neurological deficit.