We investigated the osteopromotive properties of plasmatransglutaminase (F XIII), bone marrow and venous blood on a resorbable beta-tricalcium phosphate (beta-TCP) scaffold. A baseline binding and release study of F XIII from the scaffold showed a continuous release of 18% of the total dose after 48 h. The main study consisted of 18 adult sheep with cylindrical defects in both tibiae. The defects were filled with a beta-TCP cylinder impregnated either with bone marrow, venous blood, F XIII or sheep were treated with 1250 IU F XIII intravenously over 14 days (n = 4 in each group). The defects were left open in two sheep. QCT and histology was performed after 6 and 12 weeks. The best bone ingrowth was seen after 6 weeks in the bone marrow group and after 12 weeks in the local F XIII group. The highest ingrowth on the inside of the cylinder proving the osteopromoting potential of F XIII was found in the local F XIII group. In our opinion F XIII is a good and readily available osteopromoting agent which can be used with beta-TCP in cases of bone deficit to promote bone regeneration.

This is an experimental study on human cadaver spines. The objective of this study is to compare the pullout forces between three screw augmentation methods and two different screw designs. Surgical interventions of patients with osteoporosis increase following the epidemiological development. Biomechanically the pedicle provides the strongest screw fixation in healthy bone, whereas in osteoporosis all areas of the vertebra are affected by the disease. This explains the high screw failure rates in those patients. Therefore PMMA augmentation of screws is often mandatory. This study involved investigation of the pullout forces of augmented transpedicular screws in five human lumbar spines (L1–L4). Each spine was treated with four different methods: non-augmented unperforated (solid) screw, perforated screw with vertebroplasty augmentation, solid screw with vertebroplasty augmentation and solid screw with balloon kyphoplasty augmentation. Screws were augmented with Polymethylmethacrylate (PMMA). The pullout forces were measured for each treatment with an Instron testing device. The bone mineral density was measured for each vertebra with Micro-CT. The statistical analysis was performed with a two-sided independent student t test. Forty screws (10 per group and level) were inserted. The vertebroplasty-augmented screws showed a significant higher pullout force (mean 918.5 N, P = 0.001) than control (mean 51 N), the balloon kyphoplasty group did not improve the pullout force significantly (mean 781 N, P > 0.05). However, leakage occurred in some cases treated with perforated screws. All spines showed osteoporosis on Micro-CT. Vertebroplasty-augmented screws, augmentation of perforated screws and balloon kyphoplasty augmented screws show higher pullout resistance than non-augmented screws. Significant higher pullout forces were only reached in the vertebroplasty augmented vertebra. The perforated screw design led to epidural leakage due to the position of the perforation in the screw. The position of the most proximal perforation is critical, depending on screw design and proper insertion depth. Nevertheless, using a properly designed perforated screw will facilitate augmentation and instrumentation in osteoporotic spines.

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.

We report a case of cement leakage into the posterior spinal canal due to inadvertent pedicle perforation during balloon kyphoplasty. The leakage was corrected immediately without any sequelae. Features seen on radiography and the minimally invasive procedure used for removal are described. The postoperative radiographs of 100 consecutive patients treated with balloon kyphoplasty were subsequently reviewed. Only one patient had a similar leakage but had no neurological complications.

Zusammenfassung Operationsziel Beseitigung therapieresistenter, durch eine schmerzhafte Bandscheibendegeneration bedingter Kreuzschmerzen. Durch die Erhaltung der Beweglichkeit des betroffenen Bewegungssegments sollen die Nachteile alternativer Fusionsoperationen, insbesondere der degenerative Verschleiß von Nachbarsegmenten vermieden werden. Indikationen Therapieresistente, durch eine schmerzhafte Bandscheibendegeneration bedingte Kreuzschmerzen („degenerative disk disease“). Kontraindikationen Spondylolisthese, Skoliose, Osteoporose, Infektion, spinale Stenose, Spondylarthrose. Operationstechnik Über einen vorderen Zugang wird die Bandscheibe von ventral ausgeräumt. Entscheidend ist eine gute Mobilisierung des Bewegungssegments, ggf. mit Resektion des hinteren Längsbandes. Nach Anfrischen der Grund- und Deckplatten und Meißeln einer Nut für den Kiel der Prothese werden die Grund- und Deckplatte der Prothese eingebracht und abschließend das Polyethyleninlay eingerastet. Ergebnisse Zwischen April 2002 und Mai 2004 wurden 36 ProDisc-Bandscheibenprothesen (Synthes Spine, West Chester, PA, USA) bei 34 Patienten (26 weiblich, acht männlich, Durchschnittsalter 44,3 Jahre) implantiert. Für die klinische Bewertung wurden eine visuelle Analogskala (VAS), der Oswestry Disability Index (ODI) und der SF-36-Fragebogen benutzt. Aufnahmen der Lendenwirbelsäule in zwei Ebenen, im Stehen sowie in Flexion und Extension vervollständigten die Nachuntersuchung. Der Nachuntersuchungszeitraum betrug bei allen Patienten mindestens 1 Jahr, bei 14 Patienten 2 Jahre. 26 Patienten waren mit der Operation sehr zufrieden, fünf Patienten zufrieden und drei Patienten weniger zufrieden. Die klinischen Parameter VAS, ODI und SF-36 verbesserten sich von präoperativ bis zur 1-Jahres-Nachuntersuchung von 7,4 auf 2,8 (VAS), 48,0 auf 13,1 (ODI) und 31,3 auf 44,2 (SF-36, Physical Component Summary Score). 1 Jahr postoperativ betrug der Bewegungsumfang im Segment der Prothesenimplantation bei L4/5 durchschnittlich 10°, bei L5/S1 durchschnittlich 7°.