Biomechanical study of expandable pedicle screw fixation in severe osteoporotic bone comparing with conventional and cement-augmented pedicle screws

Abstract Background The management of thoracolumbar burst fractures traditionally involves posterior pedicle screw fixation, but it has some drawbacks. The aim of this study is to evaluate the clinical and radiological outcomes of patients with thoracolumbar burst fractures. They were treated by a modified technique that monoaxial pedicle screws instrumentation and distraction-compression technology assisted end plate reduction. Methods From March 2014 to February 2016, a retrospective study including 42 consecutive patients with thoracolumbar burst fractures was performed. The patients had undergone posterior reduction and instrumentation with monoaxial pedicle screws. The fractured vertebrae were also inserted screws as a push point. The distraction -compression technology was used as assisting end plate reduction. All patients were followed up at a minimum of 2 years. These parameters including segmental kyphosis, severity of fracture, neurological function, canal compromise and back pain were evaluated in preoperatively, postoperatively and at the final follow-up. Results The average follow-up period was 28.9 ± 4.3 months (range, 24-39mo). No patients had postoperative implant failure at recent follow-up. The mean Cobb angle of the kyphosis was improved from 14.2°to 1.1° (correction rate 92.1%). At final follow-up there was 1.5% loss of correction. The mean preoperative wedge angle was improved from 17.1 ± 7.9°to 4.4 ± 3.7°(correction rate 74.3%). The mean anterior and posterior vertebral height also showed significant improvements postoperatively, which were maintained at the final follow-up(P < 0.05). The mean visual analogue scale (VAS) scores was 8 and 1.6 in preoperation and at the last follow-up, and there was significant difference (p < 0.05). Conclusion Based on our experience, distraction-compression technology can assist reduction of collapsed endplate directly. Satisfactory fracture reduction and correction of segmental kyphosis can be achieved and maintained with the use of monoaxial pedicle screw fixation including the fractured vertebra. It may be a good treatment approach for thoracolumbar burst fractures.

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Treatment of thoracolumbar burst fractures by short-segment pedicle screw fixation using a combination of two additional pedicle screws and vertebroplasty at the level of the fracture: a finite element analysis

BMC Musculoskeletal Disorders ◽

10.1186/s12891-017-1623-0 ◽

2017 ◽

Vol 18 (1) ◽

Cited By ~ 11

Author(s):

Jen-Chung Liao ◽

Weng-Pin Chen ◽

Hao Wang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Short Segment ◽

Element Analysis ◽

Thoracolumbar Burst Fractures ◽

Burst Fractures

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Removal of broken pedicle screws

Journal of Neurosurgery Spine ◽

10.3171/spi.2001.95.1.0150 ◽

2001 ◽

Vol 95 (1) ◽

pp. 150-151 ◽

Cited By ~ 2

Author(s):

Kei Miyamoto ◽

Katsuji Shimizu ◽

Ken Kouda ◽

Hideo Hosoe

Keyword(s):

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

New Method ◽

Content Type ◽

Screw Hole ◽

Narrow Slot ◽

Power Drill ◽

Diamond Burr

✓ The authors describe a simple, new method for removing broken pedicle screws. Under microscopic visualization a straight, narrow slot is etched in the broken surface of the pedicle screw by using a power drill with a 2-mm diamond burr. A minus screwdriver is then inserted into the slot, and the broken screw is rotated and removed. There is no need to enlarge the screw hole around the broken screw or to use any special devices. The authors succeeded in removing broken screws in two cases, and there were no complications. This method allows preservation of both the pedicle and the screw hole. Consequently, it is possible to insert new pedicle screws into the same hole without losing the strength and stability of pedicle screw fixation. The authors recommend this simple and new method for removal of broken pedicle screws.

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The Benefits of Cement Augmentation of Pedicle Screw Fixation Are Increased in Osteoporotic Bone: A Finite Element Analysis

Spine Deformity ◽

10.1016/j.jspd.2014.03.002 ◽

2014 ◽

Vol 2 (4) ◽

pp. 248-259 ◽

Cited By ~ 7

Author(s):

Wenhai Wang ◽

George R. Baran ◽

Hitesh Garg ◽

Randal R. Betz ◽

Missoum Moumene ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screw Fixation ◽

Cement Augmentation ◽

Osteoporotic Bone ◽

Element Analysis

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Balancing Rigidity and Safety of Pedicle Screw Fixation via a Novel Expansion Mechanism in a Severely Osteoporotic Model

BioMed Research International ◽

10.1155/2015/318405 ◽

2015 ◽

Vol 2015 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Thomas M. Shea ◽

James J. Doulgeris ◽

Sabrina A. Gonzalez-Blohm ◽

William E. Lee ◽

Kamran Aghayev ◽

...

Keyword(s):

Cortical Bone ◽

Pedicle Screw ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Cortical Layer ◽

Fixation Strength ◽

Osteoporotic Bone ◽

Pullout Strength ◽

Initial Fixation ◽

Increased Risk

Many successful attempts to increase pullout strength of pedicle screws in osteoporotic bone have been accompanied with an increased risk of catastrophic damage to the patient. To avoid this, a single-armed expansive pedicle screw was designed to increase fixation strength while controlling postfailure damage away from the nerves surrounding the pedicle. The screw was then subsequently tested in two severely osteoporotic models: one representing trabecular bone (with and without the presence of polymethylmethacrylate) and the other representing a combination of trabecular and cortical bone. Maximum pullout strength, stiffness, energy to failure, energy to removal, and size of the resulting block damage were statistically compared among conditions. While expandable pedicle screws produced maximum pullout forces less than or comparable to standard screws, they required a higher amount of energy to be fully removed from both models. Furthermore, damage to the cortical layer in the composite test blocks was smaller in all measured directions for tests involving expandable pedicle screws than those involving standard pedicle screws. This indicates that while initial fixation may not differ in the presence of cortical bone, the expandable pedicle screw offers an increased level of postfailure stability and safety to patients awaiting revision surgery.

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Freehand pedicle screw fixation: A safe recipe for dorsal, lumbar and sacral spine

Pakistan Journal of Medical Sciences ◽

10.12669/pjms.35.3.981 ◽

2019 ◽

Vol 35 (3) ◽

Author(s):

Muhammad Junaid ◽

Ali Afzal ◽

Anisa Kalsoom ◽

Syed Sarmad Bukhari

Keyword(s):

Pedicle Screw ◽

Screw Fixation ◽

Tertiary Care ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Tertiary Care Centre ◽

Disc Space ◽

Creative Commons ◽

Open Access Article ◽

Sacral Spine

Objective: To determine outcome of freehand pedicle screw fixation for dorsal, lumbar and sacral fractures at a tertiary care centre in the developing world. Methods: A retrospective review was performed of 150 consecutive patients who underwent pedicle screw fixation from January 1, 2012 to 31st December 2017. A total of 751 pedicle screws were placed. Incidence and extent of cortical breach by misplaced pedicle screw was determined by review of intra-operative and post-operative radiographs and/or computed tomography. Results: Among the total 751 free hand placed pedicle screws, four screws (0.53%) were repositioned due to a misdirected trajectory towards the disc space. six screws (0.79%) were identified to have cause moderate breach while four screws (0.53%) cause severe breach. There was no occurrence of iatrogenic nerve root damage or violation of the spinal canal. Conclusion: Free hand pedicle screw placement based on external landmarks showed remarkable safety and accuracy in our center. The authors conclude that assiduous adherence to technique and preoperative planning is vital to success. doi: https://doi.org/10.12669/pjms.35.3.981 How to cite this:Junaid M, Afzal A, Kalsoom A, Bukhari SS. Freehand pedicle screw fixation: A safe recipe for dorsal, lumbar and sacral spine. Pak J Med Sci. 2019;35(3):---------. doi: https://doi.org/10.12669/pjms.35.3.981 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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