Restricted cement augmentation in unstable geriatric midthoracic fractures treated by long-segmental posterior stabilization leads to a comparable construct stability

AbstractThe goal of this study is to compare the construct stability of long segmental dorsal stabilization in unstable midthoracic osteoporotic fractures with complete pedicle screw cement augmentation (ComPSCA) versus restricted pedicle screw cement augmentation (ResPSCA) of the most cranial and caudal pedicle screws under cyclic loading. Twelve fresh frozen human cadaveric specimens (Th4–Th10) from individuals aged 65 years and older were tested in a biomechanical cadaver study. All specimens received a DEXA scan and computer tomography (CT) scan prior to testing. All specimens were matched into pairs. These pairs were randomized into the ComPSCA group and ResPSCA group. An unstable Th7 fracture was simulated. Periodic bending in flexion direction with a torque of 2.5 Nm and 25,000 cycles was applied. Markers were applied to the vertebral bodies to measure segmental movement. After testing, a CT scan of all specimens was performed. The mean age of the specimens was 87.8 years (range 74–101). The mean T-score was − 3.6 (range − 1.2 to − 5.3). Implant failure was visible in three specimens, two of the ComPSCA group and one of the ResPSCA group, affecting only one pedicle screw in each case. Slightly higher segmental movement could be evaluated in these three specimens. No further statistically significant differences were observed between the study groups. The construct stability under cyclic loading in flexion direction of long segmental posterior stabilization of an unstable osteoporotic midthoracic fracture using ResPSCA seems to be comparable to ComPSCA.

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Posterior monoaxial screw fixation combined with distraction-compression technology assisted endplate reduction for thoracolumbar burst fractures: a retrospective study

BMC Musculoskeletal Disorders ◽

10.1186/s12891-020-3038-6 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Xuhong Xue ◽

Sheng Zhao

Keyword(s):

Retrospective Study ◽

Pedicle Screw ◽

Screw Fixation ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Thoracolumbar Burst Fractures ◽

Correction Rate ◽

Burst Fractures ◽

The Mean

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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Three-dimensional fluoroscopy-guided percutaneous thoracolumbar pedicle screw placement

Journal of Neurosurgery Spine ◽

10.3171/spi.2003.99.3.0324 ◽

2003 ◽

Vol 99 (3) ◽

pp. 324-329 ◽

Cited By ~ 22

Author(s):

Langston T. Holly ◽

Kevin T. Foley

Keyword(s):

Pedicle Screw ◽

Three Dimensional ◽

Pedicle Screws ◽

Screw Placement ◽

Content Type ◽

Image Guided ◽

Spinal Navigation ◽

Mean Diameter ◽

The Mean ◽

Fine Print

✓ The authors sought to evaluate the feasibility and accuracy of three-dimensional (3D) fluoroscopic guidance for percutaneous placement of thoracic and lumbar pedicle screws in three cadaveric specimens. After attaching a percutaneous dynamic reference array to the surgical anatomy, an isocentric C-arm fluoroscope was used to obtain images of the region of interest. Light-emitting diodes attached to the C-arm unit were tracked using an electrooptical camera. The image data set was transferred to the image-guided workstation, which performed an automated registration. Using the workstation display, pedicle screw trajectories were planned. An image-guided drill guide was passed through a stab incision, and this was followed by sequential image-guided pedicle drilling, tapping, and screw placement. Pedicle screws of various diameters (range 4–6.5 mm) were placed in all pedicles greater than 4 mm in diameter. Postoperatively, thin-cut computerized tomography scans were obtained to determine the accuracy of screw placement. Eighty-nine (94.7%) of 94 percutaneous screws were placed completely within the cortical pedicle margins, including all 30 lumbar screws (100%) and 59 (92%) of 64 thoracic screws. The mean diameter of all thoracic pedicles was 6 mm (range 2.9–11 mm); the mean diameter of the five pedicles in which wall violations occurred was 4.6 mm (range 4.1–6.3 mm). Two of the violations were less than 2 mm beyond the cortex; the others were between 2 and 3 mm. Coupled with an image guidance system, 3D fluoroscopy allows highly accurate spinal navigation. Results of this study suggest that this technology will facilitate the application of minimally invasive techniques to the field of spine surgery.

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Biomechanical analysis of stiffness and fracture displacement after using PMMA-augmented sacroiliac screw fixation for sacrum fractures

Biomedical Engineering / Biomedizinische Technik ◽

10.1515/bmt-2016-0235 ◽

2017 ◽

Vol 62 (4) ◽

pp. 421-428 ◽

Cited By ~ 14

Author(s):

Andreas Höch ◽

Richard Schimpf ◽

Niels Hammer ◽

Stefan Schleifenbaum ◽

Michael Werner ◽

...

Keyword(s):

Screw Fixation ◽

Pedicle Screws ◽

Osteoporotic Fractures ◽

Fragility Fractures ◽

Cement Augmentation ◽

Biomechanical Analysis ◽

Human Donor ◽

Sacroiliac Screw ◽

Fracture Stabilization ◽

Sacroiliac Screw Fixation

AbstractCement augmentation of pedicle screws is the gold standard for the stabilization of osteoporotic fractures of the spine. In-screw cement augmentation, in which cement is injected through the cannula, is another option for fracture stabilization of fragility fractures of the sacrum. However, biomechanical superiority of this technique compared to conventional sacroiliac screw fixation has not been tested. The present study compares the stability of cement-augmented and non-cement-augmented sacroiliac screw fixation in osteoporotic sacrum fractures under cyclic loading. Eight human donor pelvises with intact ligaments and 5

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Surgical treatment of degenerative and traumatic spinal diseases with expandable screws in patients with osteoporosis: 2-year follow-up clinical study

Journal of Neurosurgery Spine ◽

10.3171/2016.3.spine151294 ◽

2016 ◽

Vol 25 (5) ◽

pp. 610-619 ◽

Cited By ~ 15

Author(s):

Roberto Gazzeri ◽

Raffaelino Roperto ◽

Claudio Fiore

Keyword(s):

Pedicle Screw ◽

Spinal Instrumentation ◽

Pedicle Screws ◽

Posterior Fixation ◽

Spinal Diseases ◽

Fixation Failure ◽

Increased Risk ◽

Screw Breakage ◽

The Mean

OBJECTIVE Pedicle screw instrumentation of the osteoporotic spine carries an increased risk of screw loosening, pullout, and fixation failure. A variety of techniques have been used clinically to improve pedicle screw fixation in the presence of compromised bone. Pedicle screws may be augmented with cement, but this may lead to cement leakage and result in disastrous consequences. To avoid these complications, a multiaxial expandable pedicle screw has been developed. This was a prospective, single-center study designed to evaluate the clinical results of patients with osteoporosis with traumatic and degenerative spinal diseases treated with expandable pedicle screws. METHODS Thirty-three patients (mean age 61.4 years) with osteoporosis and traumatic or degenerative spinal diseases underwent spinal posterior fixation with expandable screws. Preoperative and postoperative visual analog scale (VAS) for pain and Oswestry Disability Index (ODI) questionnaire scores were obtained. The immediate postoperative screw position was measured and compared with the final position on lateral plain radiographs and axial CT scans at the 1- and 2-year follow-up examinations. RESULTS A total of 182 pedicle screws were used, including 174 expandable and 8 regular screws. The mean preoperative patient VAS score improved from 8.2 to 3.6 after surgery. The mean ODI score improved from 83.7% before surgery to 29.7% after the operation and to 36.1% at the final follow-up. No screw migration had occurred at the 1-year follow-up, but 1 screw breakage/migration was visualized on spinal radiography at the 2-year follow-up. CONCLUSIONS The results of this study show that the multiaxial expandable pedicle screw is a safe and practical technique for patients with osteoporosis and various spinal diseases and adds a valuable tool to the armamentarium of spinal instrumentation.

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Biomechanical Comparison of Translaminar Versus Pedicle Screws at T1 and T2 in Long Subaxial Cervical Constructs

Operative Neurosurgery ◽

10.1227/01.neu.0000345642.50726.a3 ◽

2009 ◽

Vol 65 (suppl_6) ◽

pp. ons167-ons172 ◽

Cited By ~ 2

Author(s):

Matthew J. McGirt ◽

Edward G. Sutter ◽

Risheng Xu ◽

Daniel M. Sciubba ◽

Jean-Paul Wolinsky ◽

...

Keyword(s):

Pedicle Screw ◽

Rotational Motion ◽

Pedicle Screws ◽

Rigid Fixation ◽

Lateral Bending ◽

Flexion Extension ◽

Translaminar Screw ◽

Cyclical Loading ◽

The Mean ◽

Upper Thoracic

Abstract Objective: The first in vitro biomechanical investigation comparing the immediate and postcyclical rigidities of thoracic translaminar versus pedicle screws in posterior constructs crossing the cervicothoracic junction (CTJ). Methods: Ten human cadaveric spines underwent C4–C6 lateral mass screw and T1–T2 translaminar (n = 5) versus pedicle (n = 5) screw fixation. Spines were then potted in polymethylmethacrylate bone cement and placed on a materials testing machine. Rotation about the axis of bending was measured using passive retroreflective markers and infrared motion capture cameras. The motion of C6 relative to T2 in flexion-extension and lateral bending was assessed uninstrumented, immediately after instrumentation, and after 40,000 cycles of 4 N•m flexion-extension and lateral bending moments at 1 Hz. The effect of instrumentation and cyclical loading on rotational motion across the CTJ was analyzed for significance. Results: Compared with preinstrumented spines, pedicle and translaminar screw constructs significantly (P < 0.001) decreased motion during flexion-extension and lateral bending. After cyclical loading, rotational motion at the CTJ was significantly increased (P < 0.05) during flexion-extension and lateral bending in both groups. With flexion-extension, the mean rotational motion across the CTJ was similar in the translaminar and pedicle constructs immediately after fixation, but slightly greater (P = 0.03) after cyclical loading in the translaminar versus the pedicle screw constructs (0.39 degrees versus 0.26 degrees). Nevertheless, after cyclical loading, the mean angular motion across the CTJ remained less than one half of a degree in both groups. With lateral bending, the mean rotational motion was similar in both translaminar and pedicle screw constructs. Conclusion: Both upper thoracic translaminar and pedicle screws allow for rigid fixation at the CTJ. Although translaminar screw constructs demonstrated one eighth of a degree more motion at the CTJ after cycling, this minimal difference is likely less than would influence the biological fusion process. Upper thoracic translaminar screws are a biomechanically effective option to rigidly stabilize the CTJ.

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First in-human report of the clinical accuracy of thoracolumbar percutaneous pedicle screw placement using augmented reality guidance

Neurosurgical FOCUS ◽

10.3171/2021.5.focus21217 ◽

2021 ◽

Vol 51 (2) ◽

pp. E10

Author(s):

Alexander T. Yahanda ◽

Emelia Moore ◽

Wilson Z. Ray ◽

Brenton Pennicooke ◽

Jack W. Jennings ◽

...

Keyword(s):

Augmented Reality ◽

Lower Extremity ◽

Pedicle Screw ◽

Pedicle Screws ◽

Screw Placement ◽

Spinal Tumors ◽

Pedicle Screw Placement ◽

Percutaneous Pedicle Screw ◽

Clinical Accuracy ◽

The Mean

OBJECTIVE Augmented reality (AR) is an emerging technology that has great potential for guiding the safe and accurate placement of spinal hardware, including percutaneous pedicle screws. The goal of this study was to assess the accuracy of 63 percutaneous pedicle screws placed at a single institution using an AR head-mounted display (ARHMD) system. METHODS Retrospective analyses were performed for 9 patients who underwent thoracic and/or lumbar percutaneous pedicle screw placement guided by ARHMD technology. Clinical accuracy was assessed via the Gertzbein-Robbins scale by the authors and by an independent musculoskeletal radiologist. Thoracic pedicle subanalysis was also performed to assess screw accuracy based on pedicle morphology. RESULTS Nine patients received thoracic or lumbar AR-guided percutaneous pedicle screws. The mean age at the time of surgery was 71.9 ± 11.5 years and the mean number of screws per patient was 7. Indications for surgery were spinal tumors (n = 4, 44.4%), degenerative disease (n = 3, 33.3%), spinal deformity (n = 1, 11.1%), and a combination of deformity and infection (n = 1, 11.1%). Presenting symptoms were most commonly low-back pain (n = 7, 77.8%) and lower-extremity weakness (n = 5, 55.6%), followed by radicular lower-extremity pain, loss of lower-extremity sensation, or incontinence/urinary retention (n = 3 each, 33.3%). In all, 63 screws were placed (32 thoracic, 31 lumbar). The accuracy for these screws was 100% overall; all screws were Gertzbein-Robbins grade A or B (96.8% grade A, 3.2% grade B). This accuracy was achieved in the thoracic spine regardless of pedicle cancellous bone morphology. CONCLUSIONS AR-guided surgery demonstrated a 100% accuracy rate for the insertion of 63 percutaneous pedicle screws in 9 patients (100% rate of Gertzbein-Robbins grade A or B screw placement). Using an ARHMS system for the placement of percutaneous pedicle screws showed promise, but further validation using a larger cohort of patients across multiple surgeons and institutions will help to determine the true accuracy enabled by this technology.

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Increased pedicle screw pullout strength with vertebroplasty augmentation in osteoporotic spines

Journal of Neurosurgery Spine ◽

10.3171/spi.2002.96.3.0309 ◽

2002 ◽

Vol 96 (3) ◽

pp. 309-312 ◽

Cited By ~ 30

Author(s):

John S. Sarzier ◽

Avery J. Evans ◽

David W. Cahill

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Pullout Strength ◽

Mineral Density ◽

Content Type ◽

Pullout Force ◽

Grade Ii ◽

The Mean ◽

Grade Iii ◽

Fine Print

Object. The authors conducted a biomechanical study to evaluate pedicle screw pullout strength in osteoporotic cadaveric spines. Nonaugmented hemivertebrae were compared with pressurized polymethylmethacrylate (PMMA)—augmented hemivertebrae. Methods. Six formalin-fixed cadaveric thoracolumbar spines at least two standard deviations below the mean bone mineral density (BMD) for age were obtained. Radiographic and BMD studies were correlated to grades I, II, and III osteoporosis according to the Jekei scale. Each of the 21 vertebrae underwent fluoroscopic placement of 6-mm transpedicular screws with each hemivertebra serving as the control for the contralateral PMMA-augmented hemivertebra. Pedicle screws were then evaluated for biomechanical axial pullout resistance. Augmented hemivertebrae axial pullout forces were increased (p = 0.0005). The mean increase in pullout force was 181% for Grade I, 206% for Grade II, and 213% for Grade III osteoporotic spines. Augmented Grade I osteoporotic spines demonstrated axial pullout forces near those levels reported in the literature for nonosteoporotic specimens. Augmented Grade II osteoporotic specimens demonstrated increases to levels found in nonaugmented vertebrae with low-normal BMD. Augmented Grade III osteoporotic specimens had increases to levels equal to those found in nonaugmented Grade I vertebrae. Conclusions. Augmentation of osteoporotic vertebrae in PMMA-assisted vertebroplasty can significantly increase pedicle screw pullout forces to levels exceeding the strength of cortical bone. The maximum attainable force appears to be twice the pullout force of the nonaugmented pedicle screw for each osteoporotic grade.

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The Value of Cement Augmentation in Patients With Diminished Bone Quality Undergoing Thoracolumbar Fusion Surgery: A Review

Global Spine Journal ◽

10.1177/2192568220965526 ◽

2021 ◽

Vol 11 (1_suppl) ◽

pp. 37S-44S

Author(s):

Joshua M. Kolz ◽

Brett A. Freedman ◽

Ahmad N. Nassr

Keyword(s):

Bone Quality ◽

Revision Surgery ◽

Revision Rate ◽

Pedicle Screws ◽

Cost Effective ◽

Cement Augmentation ◽

Fusion Surgery ◽

The Mean ◽

The Cost ◽

Mean Cost

Study Design: Systematic review. Objectives: Osteoporosis predisposes patients undergoing thoracolumbar (TL) fusion to complications and revision surgery. Cement augmentation (CA) improves fixation of pedicle screws to reduce these complications. The goal of this study was to determine the value and cost-effectiveness of CA in TL fusion surgery. Methods: A systematic literature review was performed using an electronic database search to identify articles discussing the cost or value of CA. As limited information was available, the review was expanded to determine the mean cost of primary TL fusion, revision TL fusion, and the prevalence of revision TL fusion to determine the decrease of revision surgery necessary to make CA cost-effective. Results: Two studies were identified discussing the cost and value of CA. The mean cost of CA for two vertebral levels was $10 508, while primary TL fusion was $87 346 and revision TL fusion was $76 825. Using a mean revision rate of 15.4%, the use of CA for TL fusion would need to decrease revision rates by 13.7% to be cost-effective. Comparison studies showed a decreased revision rate of 11.3% with CA, which approaches this value. Conclusion: CA for TL fusion surgery improves biomechanical fixation of pedicle screws and decreases complications and revision surgery in patients with diminished bone quality. The costs of CA are substantial and reported decreases in revision rates approach but do not reach the calculated value to be a cost-effective technique. Future studies will need to focus on the optimal CA technique to decrease complications, revisions, and costs.

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Can cavity-based pedicle screw augmentation decrease screw loosening? A biomechanical in vitro study

European Spine Journal ◽

10.1007/s00586-020-06676-1 ◽

2020 ◽

Author(s):

Hans-Joachim Riesner ◽

Thomas R. Blattert ◽

Renate Krezdorn ◽

Simone Schädler ◽

Hans-Joachim Wilke

Keyword(s):

Cyclic Loading ◽

Pedicle Screw ◽

Pedicle Screws ◽

In Vitro Study ◽

Complex Loading ◽

Control Group ◽

Slight Reduction ◽

Screw Loosening ◽

Screw Augmentation

Abstract Purpose In an osteoporotic vertebral body, cement-augmented pedicle screw fixation could possibly be optimized by the creation of an initial cavity. The aim of this study is to compare three test groups with regard to their loosening characteristics under cyclic loading. Methods Eighteen human, osteoporotic spine segments were divided in three groups. Flexibility tests and cyclic loading tests were performed with an internal fixator. The screws were fixed after creation a cavity and with cement (cavity-augmented group), without cavity and with cement (augmented group), and without cavity and without cement (control group). Cyclic loading up to 100,000 cycles was applied with a complex loading protocol. Screw loosening was measured with flexibility tests after implantation and after cyclic loading. Cement distribution was visualized from CT scans. Results In all groups, range of motion increased during cyclic loading, representing significant screw loosening after 100,000 cycles. In both augmented groups, screw loosening was less pronounced than in the control group. The cavity-augmented group showed only a slight tendency of screw loosening, but with smaller variations compared to both other groups. This may be explained with a trend for a more equal and homogeneous cement volume around each tip for the cavity-augmented group. Conclusion This study demonstrated that creating a cavity may allow a more equal fixation of all pedicle screws with slight reduction of loosening. However, augmentation only through a cannulated screw is almost equivalent, if care is taken that enough cement volume can be pushed out around the tip of the screw.

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Does robot-assisted navigation influence pedicle screw selection and accuracy in minimally invasive spine surgery?

Neurosurgical FOCUS ◽

10.3171/2021.10.focus21526 ◽

2022 ◽

Vol 52 (1) ◽

pp. E4

Keyword(s):

Minimally Invasive ◽

Pedicle Screw ◽

Surgical Navigation ◽

Lumbar Fusion ◽

Pedicle Screws ◽

Screw Placement ◽

Robotic Assistance ◽

Pedicle Screw Placement ◽

Screw Length ◽

The Mean

OBJECTIVE The accuracy of percutaneous pedicle screw placement has increased with the advent of robotic and surgical navigation technologies. However, the effect of robotic intraoperative screw size and trajectory templating remains unclear. The purpose of this study was to compare pedicle screw sizes and accuracy of placement using robotic navigation (RN) versus skin-based intraoperative navigation (ION) alone in minimally invasive lumbar fusion procedures. METHODS A retrospective cohort study was conducted using a single-institution registry of spine procedures performed over a 4-year period. Patients who underwent 1- or 2-level primary or revision minimally invasive surgery (MIS)–transforaminal lumbar interbody fusion (TLIF) with pedicle screw placement, via either robotic assistance or surgical navigation alone, were included. Demographic, surgical, and radiographic data were collected. Pedicle screw type, quantity, length, diameter, and the presence of endplate breach or facet joint violation were assessed. Statistical analysis using the Student t-test and chi-square test was performed to evaluate the differences in pedicle screw sizes and the accuracy of placement between both groups. RESULTS Overall, 222 patients were included, of whom 92 underwent RN and 130 underwent ION MIS-TLIF. A total of 403 and 534 pedicle screws were placed with RN and ION, respectively. The mean screw diameters were 7.25 ± 0.81 mm and 6.72 ± 0.49 mm (p < 0.001) for the RN and ION groups, respectively. The mean screw length was 48.4 ± 4.48 mm in the RN group and 45.6 ± 3.46 mm in the ION group (p < 0.001). The rates of “ideal” pedicle screws in the RN and ION groups were comparable at 88.5% and 88.4% (p = 0.969), respectively. The overall screw placement was also similar. The RN cohort had 63.7% screws rated as good and 31.4% as acceptable, while 66.1% of ION-placed screws had good placement and 28.7% had acceptable placement (p = 0.661 and p = 0.595, respectively). There was a significant reduction in high-grade breaches in the RN group (0%, n = 0) compared with the ION group (1.2%, n = 17, p = 0.05). CONCLUSIONS The results of this study suggest that robotic assistance allows for placement of screws with greater screw diameter and length compared with surgical navigation alone, although with similarly high accuracy. These findings have implied that robotic platforms may allow for safe placement of the “optimal screw,” maximizing construct stability and, thus, the ability to obtain a successful fusion.

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