Surgeon Perception of Cancellous Screw Fixation

2012 ◽  
Author(s):  
Michael J. Stoesz ◽  
James R. Jastifer ◽  
Joseph L. Chess ◽  
Bipin Patel ◽  
Peter A. Gustafson
Keyword(s):  
Cancellous Bone ◽  
Screw Fixation ◽  
Insertion Torque ◽  
Cancellous Screw ◽  
Screw Insertion ◽  
Factors Associated

The ability of surgeons to optimize screw insertion torque in nonlocking fixation constructs is important for stability, particularly in osteoporotic and cancellous bone. This study evaluated screw torque applied by surgeons during simulated cancellous fixation. It evaluated the frequency that synthetic cancellous bone were stripped by the surgeon, factors associated with bone stripping, and the ability of surgeons to recognize it.

BIOMECHANICAL STUDY OF PEDICLE SCREW FIXATION STRENGTH: ASSOCIATION OF SCREW MALPOSITION AND SCREW INSERTION TORQUE

2019 ◽  
Vol 19 (02) ◽  
pp. 1940012
Author(s):  
TSUNG-TING TSAI ◽  
YU-HUNG CHEN ◽  
CHAO-YAUG LIAO ◽  
HSIN-TZU LIN ◽  
MU-YI LIU ◽  
...  
Keyword(s):  
Real Time ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Fixation Strength ◽  
Control Group ◽  
Insertion Torque ◽  
Pullout Strength ◽  
Screw Insertion ◽  
Medial Cortex ◽  
Screw Penetration

Pedicle screws have been widely used for the treatment of spinal diseases, but improper screw placement is not uncommon and may lead to neurovascular injuries and reduced screw fixation strength. This study aimed to investigate the feasibility of using real-time screw insertion torque monitoring to prevent screw penetration. Commercially available synthetic L4 vertebrae were divided in to seven test groups based on different screw placements. Screw insertion torque and maximal pullout strength were compared among groups. The results indicated that the insertion torque gradually increased when the screw tip was within vertebral cancellous bone without penetration. However, an instantaneous decrease of torque value was observed once the screw tip penetrated the cortex wall. When compared to the control group, higher pullout strength was found for the groups with medial cortex penetration. However, vertebrae with medial cortex penetration may lead to the concern of neurovascular damage. Meanwhile, lower pullout strength was found for the groups with lateral cortex penetration and end-plate penetration, which may lead to the concern of screw loosening. We concluded that pedicle screw penetration can be judged using real-time screw insertion torque monitoring during surgery, which may aid surgeons in avoiding neurovascular injury and reduction of screw fixation strength.

Does cancellous screw insertion torque depend on bone mineral density and/or microarchitecture?

2014 ◽  
Vol 47 (2) ◽  
pp. 347-353 ◽  
Author(s):  
Rosidah Ab-Lazid ◽  
Egon Perilli ◽  
Melissa K. Ryan ◽  
John J. Costi ◽  
Karen J. Reynolds
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Insertion Torque ◽  
Cancellous Screw ◽  
Mineral Density ◽  
Screw Insertion

Pullout Strength of Screws in Foal Third Metacarpal Bone after Overdrilling a 4.5 mm Hole

1998 ◽  
Vol 11 (04) ◽  
pp. 200-204 ◽  
Author(s):  
K. Kelly ◽  
G. S. Martin ◽  
D. J. Burba ◽  
S. A. Sedrish ◽  
R. M. Moore
Keyword(s):  
Cortical Bone ◽  
Metacarpal Bone ◽  
Pullout Strength ◽  
Cancellous Screw ◽  
Bone Screw ◽  
Screw Insertion ◽  
Holding Power ◽  
Cortical Screw ◽  
Metaphyseal Bone

SummaryThe purpose of the study was to determine and to compare the in vitro pullout strength of 5.5 mm cortical versus 6.5 mm cancellous bone screws inserted in the diaphysis and metaphysis of foal third metacarpal (MCIII) bones in threaded 4.5 mm cortical bone screw insertion holes that were then overdrilled with a 4.5 mm drill bit. This information is relevant to the selection of a replacement screw if a 4.5 mm cortical screw is stripped during orthopaedic surgery. In vitro pullout tests were performed in two independent cadaver studies, each consisting of 12 foal MCIII bones. Two 4.5 mm cortical screws were placed either in the mid-diaphysis (study 1) or distal metaphysis (study 2) of MCIII bones. The holes were then overdrilled with a 4.5 mm bit and had either a 5.5 mm cortical or a 6.5 mm cancellous screw inserted; screw pullout tests were performed at a rate of 0.04 mm/s until screw or bone failure occurred.The bone failed in all of the tests in the diaphyseal and metaphyseal bone. The holding power for 6.5 mm cancellous screws was significantly (p <0.05) greater than for 5.5 mm cortical screws in both the diaphysis and metaphysis. There was not any difference in the holding power of screws in either the diaphysis or the metaphysis between proximal and distal screw holes.If a 4.5 mm cortical bone screw strips in MCIII diaphyseal or metaphyseal bone of foals, a 6.5 mm cancellous screw would provide greater holding power than a 5.5 mm cortical screw.In order to provide information regarding selection of a replacement screw if a 4.5 mm cortical screw is stripped, the in vitro pullout strength was determined for 5.5 mm cortical and 6.5 mm cancellous screws inserted in third metacarpal diaphyseal and metaphyseal bone of foals in which threaded 4.5 mm cortical bone screw insertion holes had been overdrilled with a 4.5 mm bit. The holding power of the 6.5 mm cancellous screw was significantly greater than the 5.5 mm cortical screw in both the diaphysis and metaphysis of foal third metacarpal bone. Thus, it appears that if a 4.5 mm cortical screw is stripped during orthopaedic surgery in foals, a 6.5 mm cancellous screw would provide superior holding power.

scholarly journals Cancellous Screw Fixation for Undisplaced Femoral Neck Fractures in the Elderly

2014 ◽  
Vol 22 (3) ◽  
pp. 282-286 ◽  
Author(s):  
Ruben Manohara ◽  
Shen Liang ◽  
Deborah Huang ◽  
Lingaraj Krishna
Keyword(s):  
Femoral Neck ◽  
Screw Fixation ◽  
The Elderly ◽  
Femoral Neck Fractures ◽  
Cancellous Screw

Finite element analysis of the impact of screw insertion distal to the trochanter minor on the risk of iatrogenic subtrochanteric fracture

2018 ◽  
Vol 232 (8) ◽  
pp. 807-818 ◽  
Author(s):  
Ersin Sensoz ◽  
Fatih Mehmet Özkal ◽  
Volkan Acar ◽  
Ferit Cakir
Keyword(s):  
Finite Element ◽  
Femoral Neck ◽  
Screw Fixation ◽  
Subtrochanteric Fracture ◽  
Femoral Neck Fractures ◽  
Cannulated Screws ◽  
Screw Insertion ◽  
Subtrochanteric Fractures ◽  
Trochanter Minor ◽  
The Impact

Iatrogenic subtrochanteric fractures are rarely encountered after cannulated screw fixation of femoral neck fractures; however, when they do occur, there can be several complications. Many orthopedic surgeons have concerns about the potential for iatrogenic subtrochanteric fractures after screw fixation distal to the trochanter minor; therefore, some surgeons are typically reluctant to perform this procedure. This study focused on the risk of an iatrogenic subtrochanteric fracture after treating femoral neck fractures with cannulated screws. The main purpose of the study was to understand iatrogenic subtrochanteric fractures and evaluate the effects on these fractures of an inverted triangular–shaped configuration for placement of the cannulated screws. A femur bone with an femoral neck fracture at a 40° incline to the horizontal plane was generated along with a representation of a three-dimensional finite element model, and three inverted triangular–shaped configurations for placement of the cannulated screws were investigated using finite element analyses. Statistical results indicated that the occurrence risk of ISF increases when the screw is located distal to the trochanter minor. Moreover, the risk of occurrence of intertrochanteric fracture increases when the screw is located medial to the trochanter minor because of local concentrated stress on the surface of the screw canals. To avoid the vulnerability of the subtrochanteric region, it was found that proximal placement of the screws using the inverted triangular–shaped configuration could yield better results. In addition, the results of this study provide suggestions on improved screw configurations.

Insertion Torque Profile During Pedicle Screw Insertion of the Thoracic Spine With and Without Violation of the Pedicle Wall

Spine ◽  
2006 ◽  
Vol 31 (22) ◽  
pp. E840-E846 ◽  
Author(s):  
Hwan T. Hee ◽  
Mohammad Shazad Khan ◽  
James C. Goh ◽  
Hee K. Wong
Keyword(s):  
Pedicle Screw ◽  
Thoracic Spine ◽  
Insertion Torque ◽  
Screw Insertion ◽  
Pedicle Screw Insertion ◽  
Pedicle Wall
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