SALVAGE OF FAILED SACRAL PEDICLE SCREW: BIOMECHANICAL COMPARISON OF ALA SCREW, BIGGER PEDICLE SCREW, POLYMETHYLMETHACRYLATE AUGMENTED PEDICLE SCREW
Journal Title: Journal of Turkish Spinal Surgery - Year 2009, Vol 20, Issue 1
Abstract
Background Data: Salvage procedures are needed to restore the stability of lumbosacral arthrodesis when pedicle screw fixation in the sacrum fails. Purpose: The aim of this study is to determine biomechanical differences ala, polymethylmethacrylate (PMMA) augmented and larger pedicle screws as salvage techniques for failed primary sacral pedicle screw. Material and Methods: Primary pedicle screws were inserted to 21 fresh frozen calf’s first sacral vertebra (S1) pedicle bicorticaly. The screws were pulled out in a random order at 5mm/min Materials Testing Machine. The pull-out strengths (POS) were measured. Afterwards, these pedicle screws were randomly assigned to be replaced by PMMA augmented screws (group 1), larger screws (group 2) and ala screws (group 3) as a revision technique. Finally, POS of the revision screws were recorded. Results: The mean POS of all primary screws was 1981 N/m2. Group 1: The mean POS of primary screws was 1650 N/m2. After PMMA augmentation, mean POS was 1295 N/m2 (p=0,139). The mean POS ratio (primary POS/revision POS) was 1.54±0,24. Group 2: The mean POS of primary screws was 2046 N/m2. After larger screw replacement, mean POS was 1320 N/m2 (p=0,007). The mean POS ratio was 1.84±0,22. Group 3: The mean POS of primary screws was 2247 N/m2. After ala screw insertion, mean POS was 1290 N/m2 (p=0,011). The mean POS ratio was 2.98±0,91. There was no statistical differences between POS (p=0,381) and POS ratio (p=0,185) of revision pedicle screws. Conclusion: PMMA augmentation achieved close POS to that of the primary screw so it can be concluded that it is a stronger revision technique compare to the larger or ala screws. On the other hand, there were no statistical differences between revision screws based on POS and POS ratio.
Authors and Affiliations
Alihan DERINCEK, Cenk BALÇIK, Murat ÇINAR, Mustafa UYSAL, Metin ÖZALAY
Keywords
Related Articles
- EP ID EP676587
- DOI -
- Views 121
- Downloads 0
ADULT LUMBAR SCOLIOSIS
Scoliosis in the adult is a disorder that involves a convergence of deformity and degenerative disease in the spine. It can be defined as a coronal deformity with Cobb angle of more than 10 degrees in mature patients. Th...
EFFECTS OF OBESITY ON ELECTIVE SPINAL SURGERY
Background: Obesity (Body Mass Index > 30 kg/m2) is currently a public health problem with increasing incidence. Obesity increases the challenges and complications of surgery in all surgical branches. In this study, w...
AETIOLOGICAL, CLINICAL AND LABORATORY COMPARISON OF THE PATIENTS WITH SPINAL INFECTION: PRELIMINARY REPORT
Purpose: To evaluate patients with brucellar spondylodiscitis (BS), tuberculous spondylodiscitis (TS) and pyogenic spondylodiscitis (PS) clinically, radiologically and with labaratory findings, and aid the clinician i...
ANATOMICAL COMPARISON BETWEEN HUMAN AND CALF SACRAL SPINE: FIRST SACRAL VERTEBRA PEDICLE MORPHOLOGY
Study Design: Quantitative anatomic Background Data: There is no anatomical comparative study between human versus calf first sacral vertebra in English literatüre. Purpose: To determine quantitative anatomic...
RECOVERY OF PULMONARY FUNCTION AFTER COTREL-DUBOUSSET INSTRUMENTATION
The preservation or improvement of pulmoner function in Idiopathic scoliosis is the ultimate goal of surgical treatment. In this study, we presented 26 patients, 24 adolescants, 2 adults (23 idiopathic, 3 paralytic)....