İflas etmiş pedikül vidası revizyonunda kalsiyum sülfat veya polimetilmetakrilat ile kuvvetlendirmenin biyomekanik olarak karşılaştırılması

Yıl 2014, , 202 - 206, 21.04.2014

Umit Ozgur Guler Alihan Derincek Murat Ali Hersekli Metin Ozalay Bekir Murat Cinar Emre Acaroglu

https://doi.org/10.3944/AOTT.2014.3193

Öz

Amaç: Çalışmamızın amacı başarısız pedikül vidalarına polimetilmetakrilat (PMMA) ve kalsiyum sülfat (CAS) kemik çimentolarının uygulanması ile elde edilen kuvvetlendirmenin biyomekanik sıyrılma testleriyle karşılaştırılması idi.

Çalışma planı: Altı danadan 30 lomber omur elde edilerek, kemik mineral yoğunlukları (KMY) ölçüldü. Primer poliaksiyel pedikül vidaları pediküllere rastgele yerleştirildi ve sıyrıldı. Bu esnada sıyrılma kuvvetleri ölçülerek kaydedildi. Revizyon için örnekler rastgele CAS ile güçlendirilmiş pedikül vidası grubuna (Grup 1) veya PMMA ile güçlendirilmiş pedikül vidası grubuna (Grup 2) alındı. Grupların karşılaştırılması için vida sıyrılma testleri tekrarlandı.

Bulgular: Örneklerin ortalama KMY değeri 1.006±0.116 g/cm2 olarak kaydedildi. Her iki grubun KMY sonuçları arasında istatistiksel olarak anlamlı bir fark saptanmadı (p=0.116). Birinci grupta; primer vidalarda tespit edilen sıyrılma kuvveti ortalaması 2,441.3±936.4 N; CAS kuvvetlendirmesi sonrası 2,499.5±1,425.1 N olarak belirlenirken, her iki sonuç arasında istatistiksel olarak anlamlı bir fark bulunmadı (p=0.865). İkinci grupta; primer vidaların ortalama sıyrılma kuvveti 2,876.6±926.6 N’den PMMA kuvvetlendirmesi sonrası 3,745.5±1,299.2 N’ye artış gösterirken, bu artış istatistiksel olarak anlamlı bulundu (p=0.047). Ayrıca, CAS ve PMMA ile kuvvetlendirilmiş revizyon vidalarının sıyrılma kuvvetleri değerlendirildiğinde aradaki fark istatistiksel olarak anlamlı idi (p=0.026).

Çıkarımlar: Kalsiyum sülfat kuvvetlendirmesi revizyon vidalarının sıyrılma kuvvetini primer vidaların değerleri kadar yükseltebilse de, PMMA kadar kuvvetlendirme yapamamaktadır.

Anahtar Kelimeler

Kalsiyum sülfat; pedikül vidası; PMMA; sıyrılma kuvveti.

Restoration of pull-out strength of the failed pedicle screw: biomechanical comparison of calcium sulfate vs polymethylmethacrylate augmentation

Öz

Objective: The aim of the present study was to compare calcium sulfate (CAS) and polymethylmethacrylate (PMMA) bone cements used for the augmentation of a failed pedicle screw with biomechanical pull-out strength (POS) testing.

Methods: Thirty lumbar vertebrae were harvested from 6 calves and bone mineral densities (BMD) were measured. Primary polyaxial pedicle screws were randomly inserted and pulled out and the POSs of the specimen were recorded. For revision, specimens were randomly assigned to the CAS-augmented pedicle screws group (Group 1) or PMMA-augmented pedicle screw group (Group 2). Pull-out tests were repeated to compare both groups.

Results: Mean BMD of the specimens was 1.006±0.116 g/cm2. There were no statistically significant differences between BMD results of the two groups (p=0.116). For Group 1, mean POS of primary screws was 2,441.3±936.4 N and was 2,499.5±1,425.1 N after CAS augmentation, demonstrating no statistically significant difference (p=0.865). In Group 2, mean POS of the primary screws was 2,876.6±926.6 N and significantly increased to 3,745.5±1,299.2 N after PMMA augmentation (p=0.047). There was also a significant difference in mean POS between the CAS and PMMA groups (p=0.026).

Conclusion: Although CAS augmentation facilitates a revision screw POS as strong as that of primary screws, it is not as strong as PMMA augmentation.

Anahtar Kelimeler

Calcium sulfate, pedicle screw, PMMA, pull-out strength

Kaynakça

• Lonstein JE, Denis F, Perra JH, Pinto MR, Smith MD, Winter RB. Complications associated with pedicle screws. J Bone Joint Surg Am 1999;81:1519-28.
• Chang MC, Liu CL, Chen TH. Polymethylmethacrylate augmentation of pedicle screw for osteoporotic spinal sur- gery: a novel technique. Spine 2008;33:E317-24. CrossRef
• Lotz JC, Hu SS, Chiu DF, Yu M, Colliou O, Poser RD. Carbonated apatite cement augmentation of pedicle screw fixation in the lumbar spine. Spine 1997;22:2716-23. CrossRef
• Moore DC, Maitra RS, Farjo LA, Graziano GP, Goldstein SA. Restoration of pedicle screw fixation with an in situ setting calcium phosphate cement. Spine 1997;22:1696- 705. CrossRef
• Motzkin NE, Chao EY, An KN, Wikenheiser MA, Lewallen DG. Pull-out strength of screws from polymeth- ylmethacrylate cement. J Bone Joint Surg Br 1994;76:320- 3.
• Rohmiller MT, Schwalm D, Glattes RC, Elalayli TG, Spengler DM. Evaluation of calcium sulfate paste for aug- mentation of lumbar pedicle screw pullout strength. Spine J 2002;2:255-60. CrossRef
• Spivak JM, Neuwirth MG, Labiak JJ, Kummer FJ, Ricci JL. Hydroxyapatite enhancement of posterior spinal in- strumentation fixation. Spine 1994;19:955-64. CrossRef
• Wilkes RA, Mackinnon JG, Thomas WG. Neurological deterioration after cement injection into a vertebral body. J Bone Joint Surg Br 1994;76:155.
• Yerby SA, Toh E, McLain RF. Revision of failed pedicle screws using hydroxyapatite cement. A biomechanical analysis. Spine 1998;23:1657-61. CrossRef
• Bucholz RW. Nonallograft osteoconductive bone graft substitutes. Clin Orthop Relat Res 2002;395:44-52. CrossRef
• Stürup J, Nimb L, Kramhİft M, Jensen JS. Effects of po- lymerization heat and monomers from acrylic cement on canine bone. Acta Orthop Scand 1994;65:20-3. CrossRef
• Mitzner E, Albertus P, Pelt HM, Mueller C, Strohwig A, Mueller WD. Material properties and in vitro biocompat- ibility of a newly developed bone cement. Materials Re- search 2009;12:447-54. CrossRef
• Belkoff SM, Sanders JC, Jasper LE. The effect of the monomer-to-powder ratio on the material properties of acrylic bone cement. J Biomed Mater Res 2002;63:396-9.
• Akbay A, Bozkurt G, Ilgaz O, Palaoglu S, Akalan N, Ben- zel EC. A demineralized calf vertebra model as an alter- native to classic osteoporotic vertebra models for pedicle screw pullout studies. Eur Spine J 2008;17:468-73. CrossRef
• Esses SI, Sachs BL, Dreyzin V. Complications associated with the technique of pedicle screw fixation. A selected survey of ABS members. Spine 1993;18:2231-9. CrossRef
• Okuyama K, Abe E, Suzuki T, Tamura Y, Chiba M, Sato K. Influence of bone mineral density on pedicle screw fixa- tion: a study of pedicle screw fixation augmenting poste- rior lumbar interbody fusion in elderly patients. Spine J 2001;1:402-7. CrossRef
• Yi X, Wang Y, Lu H, Li C, Zhu T. Augmentation of pedi- cle screw fixation strength using an injectable calcium sul- fate cement: an in vivo study. Spine 2008;33:2503-9. CrossRef
• Derincek A, Wu C, Mehbod A, Transfeldt EE. Biome- chanical comparison of anatomic trajectory pedicle screw versus injectable calcium sulfate graft-augmented pedicle screw for salvage in cadaveric thoracic bone. J Spinal Dis- ord Tech 2006;19:286-91. CrossRef
• Wittenberg RH, Lee KS, Shea M, White AA 3rd, Hayes WC. Effect of screw diameter, insertion technique, and bone cement augmentation of pedicular screw fixation strength. Clin Orthop Relat Res 1993;296:278-87.
• Fogel GR, Reitman CA, Liu W, Esses SI. Physical char- acteristics of polyaxial-headed pedicle screws and bio- mechanical comparison of load with their failure. Spine 2003;28:470-3. CrossRef
• Lehman RA Jr, Polly DW Jr, Kuklo TR, Cunningham B, Kirk KL, Belmont PJ Jr. Straight-forward versus anatomic trajectory technique of thoracic pedicle screw fixation: a biomechanical analysis. Spine 2003;28:2058-65. CrossRef
• Yamagata M, Kitahara H, Minami S, Takahashi K, Isobe K, Moriya H, et al. Mechanical stability of the pedi- cle screw fixation systems for the lumbar spine. Spine 1992;17(3 Suppl):S51-4. CrossRef