Revision of the failed pedicle screw in osteoporotic lumbar spine: Biomechanical comparison of kyphoplasty versus transpedicular polymethylmethacrylate augmentation

Derinçek A., Türker M., Çınar M., Çetik Ö., Kalaycıoğlu B.

Joint Diseases and Related Surgery, cilt.23, sa.2, ss.106-110, 2012 (SCI-Expanded)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 23 Sayı: 2
  • Basım Tarihi: 2012
  • Dergi Adı: Joint Diseases and Related Surgery
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED)
  • Sayfa Sayıları: ss.106-110
  • Ankara Yıldırım Beyazıt Üniversitesi Adresli: Hayır

Özet

Objectives: In this study, we aimed to compare of kyphoplasty

versus transpedicular polymethylmethacrylate (PMMA)

augmentation biomechanically in the revision of the failed pedicle

screw in osteoporotic lumbar spine.

Materials and methods: Bone mineral density (BMD) of

lumbar vertebrae collected from four bovines were measured.

Each vertebra was decalcified with hydrochloric acid solution to

obtain osteoporotic specimens. Primary polyaxial pedicle screws

were inserted into the pedicles and pulled out until they failed. The

pullout strength results of all specimens were recorded. Revision

pedicle screws were randomly inserted into the same pedicles by

either pedicle hole PMMA augmented (group 1) or kyphoplasty

(XvoidTM) PMMA augmented pedicle screws (group 2). The

pullout strength results of all specimens were re-recorded.

Results: The mean BMD significantly decreased from

1.686±227.9 g/cm2 to 1.432±157.1 g/cm2 following decalcification

(p<0.001). In group 1, the mean pullout strength of primary screws

significantly decreased from 3443±1086 N/m2 to 2088±924 N/m2

following pedicle screw augmentation (p=0.006). In group 2,

the mean pullout strength of primary screws decreased from

3702±1063 N/m2 to 3664±1057N/m2 following kyphoplasty

augmentation (p=0.934). Pedicle screw augmentation group

achieved significantly lower pullout strength values than

kyphoplasty pedicle hole augmentation group (p=0.002).

Conclusion: Although pedicle hole PMMA augmentation is

the gold standard for the failed screws in an osteoporotic bone,

kyphoplasty augmented pedicle screw seems to be more effective

method increasing the pullout strength.