Analysis of a β-tricalcium phosphate (β-TCP) bone graft soaked with bone marrow aspirate explanted during revision surgery after 28 months.

In case of revision or minimal invasive spinal surgery, the amount of autograft possibly harvested from the lamina and the spinous processes is limited. Ekanayake and Shad (Acta Neurochir 152:651–653, 2010) suggest the application of bone shavings harvested via high speed burr additionally or instead, but so far no data regarding their osteogenic potential exist. Aim of the study was to compare the osteogenic potential of bone chips and high speed burr shavings, and to evaluate the applicability of bone shavings as an autograft for spinal fusion. Bone chips and shavings from 14 patients undergoing spinal decompression surgery were analyzed using in vitro tissue culture methods. Osteoblast emigration and proliferation, viability and mineralization were investigated and histological evaluation was performed. Bone chips from all patients showed successful osteoblast emigration after average 5.5 days. In contrast, only 57% of the corresponding bone shavings successfully demonstrated osteoblast emigration within an average time span of 14.8 days. Average osteoblast mobilisation was 1.25 × 106 cells per gram from bone chips and 1.73 × 105 cells per gram from the corresponding bone shavings. No difference was observed regarding cell viability, but population doubling times of bone chip cultures were significantly lower (50.5 vs. 121 h) and mineralization was observed in osteoblasts derived from bone chips only. Although some authors suggest the general applicability of laminectomy bone shavings as autografts for spinal fusion, autologous bone grafts obtained from laminectomy bone chips are superior in terms of cell delivery, cell proliferation and mineralization.

Purpose. To compare efficacy of balloon kyphoplasty in restoring vertebral height and correcting kyphosis in patients having vertebra plana with or without osteonecrosis. Methods. 12 women and 3 men (mean age, 76 years), who had a complete vertebra plana with or without osteonecrosis (n=8 vs n=7), underwent balloon kyphoplasty. No external manoeuvres were performed before or during balloon kyphoplasty, except for positioning the patients in a prone posture on the operating table. The anterior, middle, and posterior vertebral height and the kyphotic angle were measured pre- and post-operatively with a digital imaging system. The vertebral height was measured as a percentage of the adjacent normal vertebral height. Results. Respectively in vertebra plana patients with or without osteonecrosis, the mean corrections of (1) kyphosis were 10° and 4° (p=0.099), (2) anterior vertebral height were 33% and 5% (p<0.001), (3) middle vertebral height were 38% and 18% (p=0.004), and (4) posterior vertebral height were 19% and 2% (p=0.031). Conclusion. In patients with vertebra plana, it is important to identify any osteonecrosis, which is an indication for balloon kyphoplasty to restore vertebral height and correct kyphosis.

Vertebroplasty and kyphoplasty are associated with a recurrent fracture rate of 2.4% to 23%, which is lower than the general natural history of untreated osteoporotic fractures. Some authors suggest the risk of refracture at adjacent vertebra will be reduced by prophylactic stabilization. We therefore compared the refracture rate after prophylactic balloon kyphoplasty in 60 patients randomized into groups with either monosegmental balloon kyphoplasty or adjacent prophylactic balloon kyphoplasty. The level (superior versus inferior) for prophylactic stabilization was chosen according to fracture type. We evaluated patients for 12 months using radiographs, visual analog scale scores, and SF-36 scores. We followed 23 of 30 patients in the monosegmental group and 27 of 30 patients in the prophylactic group. We observed no difference in the 1-year refracture rates between the two groups (five patients in the monosegmental group and seven in the prophylactic group). Leakage into the disc was the presumed cause of adjacent fractures in 50% of the patients. Disc leakage and refracture rate did not correlate as a result of the low patient number. Based on our data, we believe there is no indication for prophylactic stabilization of adjacent segments with balloon kyphoplasty.Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

OBJECTIVE:To eradicate treatment-resistant lower back pain caused by painful degeneration of the intervertebral disks. To avoid the disadvantages of alternative fusion surgery, especially degenerative wear and tear on adjacent segments, by maintaining the mobility of the affected motion segments.INDICATIONS:Treatment-resistant lower back pain due to painful degeneration of the intervertebral disks ("degenerative disk disease").CONTRAINDICATIONS:Spondylolisthesis, scoliosis, osteoporosis, infection, spinal stenosis, degeneration of the vertebral articulations.SURGICAL TECHNIQUE:The intervertebral disk is excised through an anterior approach. It is essential to retain good mobility of the motion segment, if necessary, by resection of the posterior longitudinal ligament. After revitalization of the vertebral base and cover plates and chiseling of a groove for the keel of the prosthesis, the upper and lower prosthetic plates are inserted and the polyethylene inlay is locked into place.RESULTS:From April 2002 to May 2004, 36 ProDisc (Synthes Spine, West Chester, PA, USA) modular intervertebral disk prostheses were implanted in 34 patients (26 women, eight men, average age 44.3 years). Clinical evaluation was based on the visual analog scale (VAS), the Oswestry Disability Index (ODI), and the SF-36 Questionnaire. Follow-up assessment also included radiographic views of the lumbar spine in two planes in flexion and extension and standing. The follow-up interval for all patients was at least 1 year and 2 years for 14 patients. 26 patients were very satisfied with the operation, five patients were satisfied, and three patients were less satisfied. The clinical parameters recorded on the VAS, ODI and SF-36 improved from 7.4 to 2.8 (VAS), 48.0 to 13.1 (ODI) and 31.3 to 44.2 (SF-36, Physical Component Summary Score) from the time of the preoperative assessment to the 1-year follow-up. The range of motion at the segment with the implanted prosthesis was 10 degrees on average at L4/5 and 7 degrees on average at L5/S1 1 year postoperatively.