RESUMO
STUDY DESIGN: An in vitro biomechanical study. OBJECTIVE: The aim of this study was to determine the effect of an optional sleeve on height restoration and compare it with the fracture reduction achieved by a commercially available inflatable bone tamp under simulated physiological load (110 N). SUMMARY OF BACKGROUND DATA: Loss of reduction after bone tamp deflation before cement injection still remains a concern. The optional sleeve surrounds the bone tamp to help maintain height during the kyphoplasty procedure while filling the created cavity with bone cement on the contralateral side. METHODS: Eighteen osteoporotic vertebral bodies (VBs) (T11-L4) were alternately assigned to 1 of the 2 treatment groups: group A: KYPHON (Kyphon Inc.) and group B: AFFIRM with sleeve (Globus Medical Inc.). The VBs were compressed axially at a rate of 5 mm/min until compressed to 40% of the initial anterior height. The fractured VBs then underwent kyphoplasty with cement augmentation while still maintaining load (110 N). The augmented VBs were then recompressed and anterior VB height (mm) and wedge angle (degrees) were measured initially after mechanically creating an anterior wedge fracture, and after repairing the compression fracture. The effect of kyphoplasty on vertebral height, kyphotic angle, cement volumes, and inflation pressures were compared between the treatment groups. Failure load (N) data were compared between intact and repaired VBs. RESULTS: Average percentage of lost VB height restored in group A was 30%, compared with 56% for group B. The mean changes in wedge angle were similar to those of vertebral height measurements. No significant difference in mean inflation pressures (group A: 175±37 psi; group B: 160±36 psi) were found between the 2 groups. Average percentage increase in failure load was 241% and 212% in groups A and B, respectively. CONCLUSIONS: Some height restoration was observed using the commercially available bone tamp in fractured VBs under simulated physiological load. The use of an outer sleeve significantly enhanced height restoration compared with the inflatable bone tamp alone.
Assuntos
Fenômenos Biomecânicos , Cimentos Ósseos/uso terapêutico , Cifoplastia/métodos , Fraturas da Coluna Vertebral/cirurgia , Estresse Mecânico , Absorciometria de Fóton , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Fluoroscopia , Humanos , Técnicas In Vitro , Estatísticas não ParamétricasRESUMO
STUDY DESIGN: An in vitro biomechanical study. OBJECTIVE: To determine the fracture reduction achieved by a novel inflatable bone tamp under simulated physiological load. SUMMARY OF BACKGROUND DATA: Previous biomechanical studies have showed that kyphoplasty allows near-total restoration of lost vertebral height in unloaded conditions and partial height restoration under simulated physiological loads. Clinically, loss of reduction has been observed after bone tamp deflation, before cement injection. The present study evaluated fracture reduction achieved by an inflatable bone tamp during kyphoplasty while maintaining physiological load. Comparison to commercially available inflatable bone tamp was also performed. MATERIALS AND METHODS: Eighteen osteoporotic vertebral bodies (T11-L4) were alternately assigned to one of the 2 treatment groups: group A-AFFIRM (Algea Thearpies, a division of Globus Medical Inc., Audubon, PA); and group B-KYPHON (Kyphon Inc., Sunnyvale, CA). The vertebral bodies were compressed axially on an MTS Bionix 858 machine at a rate of 5 mm/min until compressed to 40% of the initial anterior height. Load versus displacement was recorded. The fractured VBs then underwent kyphoplasty with cement augmentation. The augmented vertebral bodies were then recompressed and anterior vertebral body height (mm) and wedge angle (degrees) was measured initially, after mechanically creating an anterior wedge fracture, and after repairing the compression fracture. Each vertebral body was subjected to 111 N load to simulate in vivo physiological loading during inflation and cement augmentation. The vertebral height, wedge angle, cement volume, and inflation pressures were compared between the treatment groups using an unpaired t test (P<0.05). Failure loads were compared between intact and repaired VBs using a paired t test (P<0.05). RESULTS: Average lost height restored in group A was 29%, and 30% in group B compared to the compressed state. Similar trends were observed in the mean changes of vertebral body wedge angle in both the groups. No significant difference in mean inflation pressures (group A 182±33 psi; group B 175±37 psi) were found between the 2 groups. Average percentage increase in failure load was 218% and 241% for groups A and B, respectively. Mean injected cement volume was 6.65±0.65 and 6.73±0.41 mL for groups A and B, respectively. CONCLUSIONS: Some height restoration was observed using the 2 bone tamps in fractured vertebral bodies under simulated physiological load. The fracture reduction achieved by the 2 inflatable bone tamps was equivalent. No significant difference between mean inflation pressures and failure load was demonstrated between the 2 groups.
Assuntos
Fenômenos Biomecânicos , Fixadores Internos , Cifoplastia/métodos , Fraturas da Coluna Vertebral/terapia , Estresse Mecânico , Suporte de Carga/fisiologia , Idoso , Idoso de 80 Anos ou mais , Cimentos Ósseos , Cadáver , Feminino , Humanos , Técnicas In Vitro , Masculino , Coluna VertebralRESUMO
STUDY DESIGN: Prospective, multicenter, randomized, and controlled Investigational Device Exemption clinical trial. OBJECTIVE: To compare the clinical safety and effectiveness of the selectively constrained SECURE-C (Globus Medical, Audubon, PA) Cervical Artificial Disc to anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Cervical total disc replacement has been developed as an alternative to ACDF by allowing segmental motion. Current cervical total disc replacement designs incorporate constrained and unconstrained metal-on-metal or metal-on-polymer articulating designs with various means of fixation. METHODS: A total of 380 patients from 18 investigational sites were prospectively enrolled in the study. Patients were randomized, treated surgically, and evaluated postoperatively at 6 weeks, 3 months, 6 months, 12 months, and 24 months. Clinical outcomes include overall success, visual analogue scale pain (right arm, left arm, and neck), neck disability index, neurological status, Short Form 36 (SF-36) Health Status Survey questionnaires, range of motion, and adverse events. Bayesian statistical methods were used to analyze the outcomes. RESULTS: Overall success results demonstrated statistical superiority of the randomized SECURE-C group compared with the randomized ACDF group at 24 months, with a posterior probability of 100% using the protocol-specified criteria and 98.1% using Food and Drug Administration-defined criteria. At 24 months postoperatively, SECURE-C demonstrated clinically significant improvement in pain and function in terms of neck disability index, visual analogue scale, and 36-Item Short Form Health Survey. At 24 months, the percentage of patients experiencing secondary surgical interventions at the index level was statistically lower for the SECURE-C group (2.5%) than the ACDF group (9.7%). At 24 months, 84.6% of as-treated SECURE-C patients were range-of-motion successes. Satisfaction was high among SECURE-C patients. CONCLUSION: The selectively constrained SECURE-C Cervical Artificial Disc is as safe and effective as the standard of care, an anterior cervical discectomy and fusion. SECURE-C is statistically superior in terms of overall success, index-level subsequent surgical procedures, and patient satisfaction, making it an attractive surgical option for patients with symptomatic cervical disc disease. LEVEL OF EVIDENCE: 1.