scholarly journals Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

2016 ◽  
Author(s):  
Hope B. Pearson ◽  
Christopher J. Dobbs ◽  
Eric Grantham ◽  
Glen L. Niebur ◽  
James L. Chappuis ◽  
...  
Keyword(s):  
Back Pain ◽  
Pedicle Screw ◽  
Statistical Power ◽  
Lumbar Fusion ◽  
Pedicle Screws ◽  
Screw Loosening ◽  
Screw Insertion ◽  
Screw Misplacement ◽  
Lumbar Spinal ◽  
Pedicle Screw Loosening

AbstractPedicle screw loosening has been implicated in recurrent back pain after lumbar spinal fusion, but the degree of loosening has not been systematically quantified in patients. Instrumentation removal is an option for patients with successful arthrodesis, but remains controversial. Here, we quantified pedicle screw loosening by measuring screw insertion and/or removal torque at high statistical power (β = 0.98) in N = 108 patients who experienced pain recurrence despite successful fusion after posterior instrumented lumbar fusion with anterior lumbar interbody fusion (L2-S1). Between implantation and removal, pedicle screw torque was reduced by 58%, indicating significant loosening over time. Loosening was greater in screws with evoked EMG threshold under 11 mA, indicative of screw misplacement. A theoretical stress analysis revealed increased local stresses at the screw interface in pedicles with decreased difference in pedicle thickness and screw diameter. Loosening was greatest in vertebrae at the extremities of the fused segments, but was significantly lower in segments with one level of fusion than in those with two or more.Clinical significanceThese data indicate that pedicle screws can loosen significantly in patients with recurrent back pain and warrant further research into methods to reduce the incidence of screw loosening and to understand the risks and potential benefits of instrumentation removal.

Biomechanical Effects of Lumbar Pedicle Screw Insertion Depth on Screw Loosening and Fulcrum Location

2013 ◽  
Author(s):  
Laura E. Buckenmeyer ◽  
Kristophe J. Karami ◽  
Ata M. Kiapour ◽  
Vijay K. Goel ◽  
Constantine K. Demetropoulos ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Pedicle Screws ◽  
Screw Loosening ◽  
Pullout Strength ◽  
Insertion Depth ◽  
Bone Implant ◽  
Screw Insertion ◽  
Pedicle Screw Insertion ◽  
Increased Risk ◽  
Screw Length

Osteoporosis is a critical challenge in orthopedic surgery. Osteoporotic patients have an increased risk of loosening and failure of implant constructs due to a weaker bone-implant interface than with healthy bone. Pullout strength of pedicle screws is enhanced by increased screw insertion depth. However, more knowledge is needed to define optimal pedicle screw insertion depth in relation to screw-bone interface biomechanics and the resulting loosening risk. This study evaluates the effects of screw length on loosening risk in the osteoporotic lumbar spine.

scholarly journals CT-to-fluoroscopy registration versus scan-and-plan registration for robot-assisted insertion of lumbar pedicle screws

2022 ◽  
Vol 52 (1) ◽  
pp. E8
Keyword(s):  
Pedicle Screw ◽  
Lumbar Fusion ◽  
Pedicle Screws ◽  
Retrospective Chart Review ◽  
Robot Assisted ◽  
Registration Method ◽  
Screw Insertion ◽  
Pedicle Screw Insertion ◽  
Radiology Reports ◽  
Lumbar Pedicle

OBJECTIVE Pedicle screw insertion for stabilization after lumbar fusion surgery is commonly performed by spine surgeons. With the advent of navigation technology, the accuracy of pedicle screw insertion has increased. Robotic guidance has revolutionized the placement of pedicle screws with 2 distinct radiographic registration methods, the scan-and-plan method and CT-to-fluoroscopy method. In this study, the authors aimed to compare the accuracy and safety of these methods. METHODS A retrospective chart review was conducted at 2 centers to obtain operative data for consecutive patients who underwent robot-assisted lumbar pedicle screw placement. The newest robotic platform (Mazor X Robotic System) was used in all cases. One center used the scan-and-plan registration method, and the other used CT-to-fluoroscopy for registration. Screw accuracy was determined by applying the Gertzbein-Robbins scale. Fluoroscopic exposure times were collected from radiology reports. RESULTS Overall, 268 patients underwent pedicle screw insertion, 126 patients with scan-and-plan registration and 142 with CT-to-fluoroscopy registration. In the scan-and-plan cohort, 450 screws were inserted across 266 spinal levels (mean 1.7 ± 1.1 screws/level), with 446 (99.1%) screws classified as Gertzbein-Robbins grade A (within the pedicle) and 4 (0.9%) as grade B (< 2-mm deviation). In the CT-to-fluoroscopy cohort, 574 screws were inserted across 280 lumbar spinal levels (mean 2.05 ± 1.7 screws/ level), with 563 (98.1%) grade A screws and 11 (1.9%) grade B (p = 0.17). The scan-and-plan cohort had nonsignificantly less fluoroscopic exposure per screw than the CT-to-fluoroscopy cohort (12 ± 13 seconds vs 11.1 ± 7 seconds, p = 0.3). CONCLUSIONS Both scan-and-plan registration and CT-to-fluoroscopy registration methods were safe, accurate, and had similar fluoroscopy time exposure overall.

Republished: Parapedicular vertebral augmentation with polymethylmetacrylate for pedicle screw loosening

2018 ◽  
Vol 11 (9) ◽  
pp. e7-e7 ◽  
Author(s):  
Olivier Clerk-Lamalice ◽  
Zubin Irani ◽  
Marion Growney ◽  
Douglas P Beall ◽  
Joshua A Hirsch
Keyword(s):  
Back Pain ◽  
Pedicle Screw ◽  
Low Grade ◽  
Low Back ◽  
Screw Loosening ◽  
Analog Scale ◽  
Compression Fractures ◽  
Open Surgical Procedure ◽  
The Right ◽  
Pedicle Screw Loosening

A 71-year-old man who had a L1/S1 posterior fusion revision surgery complained of increasing back pain 5 weeks after the open surgical procedure. The pain was initially estimated at 9/10 on the visual analog scale (VAS) and thought to be related to a right-sided L2 screw loosening. A right parapedicular vertebroplasty was performed and polymethylmethacrylate cement was instilled around the right pedicle screw, filling the anterior two-thirds of the vertebral body. On postvertebroplasty day 1, the patient had significant improvement in his low back pain. The pain further decreased at 1 and 3 months after the intervention (2/10 on the VAS). Vertebroplasty is a minimally invasive, accessible, effective, and long lasting treatment for compression fractures. We believe that this technique could also be indicated to treat pain related to low grade screw loosening in properly selected patients.

scholarly journals The Effect of the Lumbar Pedicle and Pediculo-Corporal Junction Histology on the Pedicle Screw Insertion Technique

2020 ◽  
Vol 8 (B) ◽  
pp. 177-180
Author(s):  
Murat Yilmaz ◽  
Beyza Alkis ◽  
Kemal Yucesoy
Keyword(s):  
Pedicle Screw ◽  
Pedicle Screws ◽  
Preparation Technique ◽  
Insertion Technique ◽  
Pilot Hole ◽  
Screw Insertion ◽  
Clinical Center ◽  
Spinal Segments ◽  
Lumbar Spinal ◽  
Lumbar Pedicle

Background Posterior lumbar pedicle screw instrumentation has gained a wide acceptance in the treatment of the various spinal lesions requiring fusion. Inserting screws into the pedicles take a great deal of skill, as the dense bony parts are not large, and a mistake could push a bone fragment into the spinal nerves, causing pain, loss of mobility and other damage. Aim: To investigate the histological and gross-anatomical properties of the pediculocorporal junction, which can have important clinical implications on the insertion technique of the pedicle screws. Study Design: This study was approved by the University Clinical Center Review Board. Human cadaveric lumbar spinal segments which were fixed with formaldehyde were used in the study. Methods: Twenty pedicles from 10 lumbar spinal segments (L3-L5) were prepared for histological and gross-anatomical investigation. Thin slice cuts were taken from the specimens and examined histologically and macroscopically. Results: There were not any differences in the histological characteristics of the pedicles and the pediculo-corporal junction. Thin compact osseous formation or web like connective tissue formation was not identifiable in the pediculo-corporal junction. Conclusion: All kind of pedicle screws can be attempted to be inserted just after preparation of the insertion point with an awl or just decortication of the entrance point with a rongeur. This can also reduce the pilot hole preparation technique related complications like perforation of the pedicle walls.  

Comparison of Pedicle Screw Loosening Mechanisms and the Effect on Fixation Strength

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Hedayeh Mehmanparast ◽  
Yvan Petit ◽  
Jean-Marc Mac-Thiong
Keyword(s):  
Pedicle Screw ◽  
Lumbar Vertebrae ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Fixation Strength ◽  
Screw Loosening ◽  
Spinal Fixation ◽  
Bending Load ◽  
Biomechanical Evaluation ◽  
Pedicle Screw Loosening

Screw loosening is a common complication in spinal fixation using pedicle screws which may lead to loss of correction and revision surgery. The mechanisms of pedicle screw loosening are not well understood. The purpose of this study was to compare the pedicle screw pullout force and stiffness subsequent or not to multidirectional cyclic bending load (toggling). Pedicle screws inserted into porcine lumbar vertebrae underwent toggling in craniocaudal (CC), mediolateral (ML) directions, and no toggling (NT) before pullout. This study suggests that toggling and in particular CC toggling should be included in biomechanical evaluation of pedicle screw fixation strength.

Augmented reality–assisted pedicle screw insertion: a cadaveric proof-of-concept study

2019 ◽  
Vol 31 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Camilo A. Molina ◽  
Nicholas Theodore ◽  
A. Karim Ahmed ◽  
Erick M. Westbroek ◽  
Yigal Mirovsky ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Pedicle Screw ◽  
User Experience ◽  
Pedicle Screws ◽  
Screw Insertion ◽  
Pedicle Screw Insertion ◽  
Insertion Method ◽  
Comparative Accuracy ◽  
Placement Accuracy ◽  
Surgical Field

OBJECTIVEAugmented reality (AR) is a novel technology that has the potential to increase the technical feasibility, accuracy, and safety of conventional manual and robotic computer-navigated pedicle insertion methods. Visual data are directly projected to the operator’s retina and overlaid onto the surgical field, thereby removing the requirement to shift attention to a remote display. The objective of this study was to assess the comparative accuracy of AR-assisted pedicle screw insertion in comparison to conventional pedicle screw insertion methods.METHODSFive cadaveric male torsos were instrumented bilaterally from T6 to L5 for a total of 120 inserted pedicle screws. Postprocedural CT scans were obtained, and screw insertion accuracy was graded by 2 independent neuroradiologists using both the Gertzbein scale (GS) and a combination of that scale and the Heary classification, referred to in this paper as the Heary-Gertzbein scale (HGS). Non-inferiority analysis was performed, comparing the accuracy to freehand, manual computer-navigated, and robotics-assisted computer-navigated insertion accuracy rates reported in the literature. User experience analysis was conducted via a user experience questionnaire filled out by operators after the procedures.RESULTSThe overall screw placement accuracy achieved with the AR system was 96.7% based on the HGS and 94.6% based on the GS. Insertion accuracy was non-inferior to accuracy reported for manual computer-navigated pedicle insertion based on both the GS and the HGS scores. When compared to accuracy reported for robotics-assisted computer-navigated insertion, accuracy achieved with the AR system was found to be non-inferior when assessed with the GS, but superior when assessed with the HGS. Last, accuracy results achieved with the AR system were found to be superior to results obtained with freehand insertion based on both the HGS and the GS scores. Accuracy results were not found to be inferior in any comparison. User experience analysis yielded “excellent” usability classification.CONCLUSIONSAR-assisted pedicle screw insertion is a technically feasible and accurate insertion method.

scholarly journals Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 12: Pedicle screw fixation as an adjunct to posterolateral fusion

2014 ◽  
Vol 21 (1) ◽  
pp. 75-78 ◽  
Author(s):  
Michael W. Groff ◽  
Andrew T. Dailey ◽  
Zoher Ghogawala ◽  
Daniel K. Resnick ◽  
William C. Watters ◽  
...  
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Clinical Outcome ◽  
Pedicle Screw ◽  
Chronic Low Back Pain ◽  
Screw Fixation ◽  
Lumbar Fusion ◽  
Pedicle Screw Fixation ◽  
Controlled Study ◽  
Low Back

The utilization of pedicle screw fixation as an adjunct to posterolateral lumbar fusion (PLF) has become routine, but demonstration of a definitive benefit remains problematic. The medical evidence indicates that the addition of pedicle screw fixation to PLF increases fusion rates when assessed with dynamic radiographs. More recent evidence, since publication of the 2005 Lumbar Fusion Guidelines, suggests a stronger association between radiographic fusion and clinical outcome, although, even now, no clear correlation has been demonstrated. Although several reports suggest that clinical outcomes are improved with the addition of pedicle screw fixation, there are conflicting findings from similarly classified evidence. Furthermore, the largest contemporary, randomized, controlled study on this topic failed to demonstrate a significant clinical benefit with the use of pedicle screw fixation in patients undergoing PLF for chronic low-back pain. This absence of proof should not, however, be interpreted as proof of absence. Several limitations continue to compromise these investigations. For example, in the majority of studies the sample size is insufficient to detect small increments in clinical outcome that may be observed with pedicle screw fixation. Therefore, no definitive statement regarding the efficacy of pedicle screw fixation as a means to improve functional outcomes in patients undergoing PLF for chronic low-back pain can be made. There appears to be consistent evidence suggesting that pedicle screw fixation increases the costs and complication rate of PLF. High-risk patients, including (but not limited to) patients who smoke, patients who are undergoing revision surgery, or patients who suffer from medical conditions that may compromise fusion potential, may appreciate a greater benefit with supplemental pedicle screw fixation. It is recommended, therefore, that the use of pedicle screw fixation as a supplement to PLF be reserved for those patients in whom there is an increased risk of nonunion when treated with only PLF.

Depth of vertebral screw insertion using a cortical bone trajectory technique in lumbar spinal fusion: radiological significance of a long cortical bone trajectory

2021 ◽  
pp. 1-6
Author(s):  
Keitaro Matsukawa ◽  
Yoshihide Yanai ◽  
Kanehiro Fujiyoshi ◽  
Takashi Kato ◽  
Yoshiyuki Yato
Keyword(s):  
Cortical Bone ◽  
Vertebral Body ◽  
Screw Loosening ◽  
Lumbar Spinal Fusion ◽  
Insertion Depth ◽  
Cortical Bone Trajectory ◽  
Screw Insertion ◽  
Bone Fusion ◽  
Screw Length ◽  
Lumbar Spinal

OBJECTIVE Contrary to original cortical bone trajectory (CBT), “long CBT” directed more anteriorly in the vertebral body has recently been recommended because of improved screw fixation and load sharing within the vertebra. However, to the authors’ knowledge there has been no report on the clinical significance of the screw length and screw insertion depth used with the long CBT technique. The aim of the present study was to investigate the influence of the screw insertion depth in the vertebra on lumbar spinal fusion using the CBT technique. METHODS A total of 101 consecutive patients with L4 degenerative spondylolisthesis who underwent single-level posterior lumbar interbody fusion at L4–5 using the CBT technique were included (mean follow-up 32.9 months). Screw loosening and bone fusion were radiologically assessed to clarify the factors contributing to these outcomes. Investigated factors were as follows: 1) age, 2) sex, 3) body mass index, 4) bone mineral density, 5) intervertebral mobility, 6) screw diameter, 7) screw length, 8) depth of the screw in the vertebral body (%depth), 9) facetectomy, 10) crosslink connector, and 11) cage material. RESULTS The incidence of screw loosening was 3.1% and bone fusion was achieved in 91.7% of patients. There was no significant factor affecting screw loosening. The %depth in the group with bone fusion [fusion (+)] was significantly higher than that in the group without bone fusion [fusion (−)] (50.3% ± 8.2% vs 37.0% ± 9.5%, respectively; p = 0.001), and multivariate logistic regression analysis revealed that %depth was a significant independent predictor of bone fusion. Receiver operating characteristic curve analysis identified %depth > 39.2% as a predictor of bone fusion (sensitivity 90.9%, specificity 75.0%). CONCLUSIONS This study is, to the authors’ knowledge, the first to investigate the significance of the screw insertion depth using the CBT technique. The cutoff value of the screw insertion depth in the vertebral body for achieving bone fusion was 39.2%.

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