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4.

Introduction Lumbar fusion in elderly patients is increasingly common. This study prospectively investigated the clinical and radiological outcome of osteoporotic patients [70 years with degenerative lumbar instability treated with fusion using a new cannulated, cemented, pedicle screw instrumentation augmented with PMMA. Materials and Methods The surgical protocols, patient records, densitometry, imaging studies, and pre-and postoperative patient-reported outcome questionnaires of 23 patients (mean age, 77 years) with a follow-up of 20-49 months were reviewed. All patients underwent postoperative 3D CT scan control to assess cement leakage and instrumentation position. Serial radiological controls were analyzed for secondary complications, i.e., adjacent fractures, hardware mobilization and radiological evidence of fusion. Results Pain and function improved at 6 months and were maintained at the final follow-up. No clinical complications secondary to PMMA leakage developed. No clinical or radiological cases of non-union were observed with a mean of 1.8 levels fused. No fractures occurred in adjacent segments. There were four cases of adjacent disc disease. Three deep infections required surgical revision without removal of material and one superficial infection, all with complete remission. ConclusionThis new instrumentation for degenerative lumbar disease in elderly patients is safe and effective.

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Agreement on the assessment of metastatic spine instability is moderate. The SINS can help improve communication among clinicians in oncology care.

Until fusion occurs, tantalum cage settlement into the vertebral body is to be expected. Further subsidence could be the result of segmental adaptative changes. Graft subsidence did not affect the clinical outcome in any of our patients during long-term follow-up. The occurrence of dynamical implant subsidence had a positive effect on cervical lordosis, especially at the posterior IH.

Good reproducibility and agreement using the first and second vertebrae above the UIV to measure the angle of PJK was found in this study.

Introduction Cement augmentation is an established method to increase the pedicle screw (PS) anchorage in osteoporotic vertebral bodies. The ideal timing for augmentation when a reposition maneuver is necessary is controversial. While augmentation of the PS before reposition maneuver may increase the force applied it on the vertebrae, it bears the risk to impair PS anchorage, whereas augmenting the PS after the maneuver may restore this anchorage and prevent early screw loosening. The purpose of the present study was to evaluate the effect of cement application timing on PS anchorage in the osteoporotic vertebral body. Methods Ten lumbar vertebrae (L1-L5) were used for testing. The left and right pedicles of each vertebra were instrumented with the same PS size and used for pairwise comparison of the two timing points for augmentation. For the reposition maneuver, the left PS was loaded axially under displacement control (2 9 ±2 mm, 3 9 ±6 mm, 3 9 ±10 mm) to simulate a reposition maneuver.Subsequently, both PS were augmented with 2 ml PMMA cement. The same force as measured during the left PS maneuver was applied to the previously augmented right hand side PS [2 9 F (±2 mm), 3 9 F (±6 mm), 3 9 F (±10 mm)]. Both PS were cyclically loaded with initial forces of ?50 and -50 N, while the lower force was increased by 5 N every 100 cycles until total failure of the PS. The PS motion was measured with a 3D motion analysis system. After cyclic loading stress, X-rays were taken to identify the PS loosening mechanism. Results In comparison with PS augmented prior to the reposition maneuver, PS augmented after the reposition maneuver showed a significant higher number of load cycles until failure (5930 ± 1899 vs 3830 ± 1706, p = 0.015). The predominant loosening mechanism for PS augmented after the reposition maneuver was PS toggling with the attached cement cloud within the trabecular bone. While PS augmented prior to the reposition, maneuver showed a motion of the screw within the cement cloud. Conclusion The time of cement application has an effect on PS anchorage in the osteoporotic vertebral body if a reposition maneuver of the instrumented vertebrae is carried out. PS augmented after the reposition maneuver showed a significant higher number of load cycles until screw loosening.