Biomechanics of Grade I degenerative lumbar spondylolisthesis. Part 2: Treatment with threaded interbody cages/dowels and pedicle screws

2001 ◽  
Vol 94 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Sedat Çagli ◽  
Neil R. Crawford ◽  
Volker K. H. Sonntag ◽  
Curtis A. Dickman
Keyword(s):  
Pedicle Screw ◽  
Degenerative Spondylolisthesis ◽  
Pedicle Screws ◽  
Cyclic Fatigue ◽  
Pedicle Screw Fixation ◽  
Biomechanical Stability ◽  
Content Type ◽  
Degenerative Lumbar Spondylolisthesis ◽  
Lumbar Spondylolisthesis ◽  
Fine Print

Object. The authors sought to determine the biomechanical effectiveness of threaded interbody cages or dowels compared with that achieved using pedicle screw instrumentation in resisting Grade I lumbar spine degenerative spondylolisthesis. Methods. Thirty-three levels obtained from seven cadaveric lumbar spines were instrumented with cages or dowels, pedicle screw/rod instrumentation, or both. Entire specimens were loaded with nonconstraining torques. Each level was loaded with anteroposterior shear forces while an optical system was used to measure the specimen's motion at individual levels. Pedicle screw/rods outperformed interbody cages and dowels in treating spondylolisthesis. Cages or dowels alone provided only moderate biomechanical stability, and their effectiveness depended heavily on the integrity of the ligaments and remaining annulus, whereas the success of pedicle screw fixation relied predominantly on the integrity of the bone for solid fixation. Little biomechanical difference was demonstrated between cages and dowels; both devices were susceptible to loosening with cyclic fatigue. Conclusions. Biomechanically, cages or dowels alone were suboptimal for treating lumbar spondylolisthesis, especially compared with pedicle screw/rods. Threaded cages or dowels used together with pedicle screws/rods created the most stable construct.

Percutaneous pedicle screw fixation of the lumbar spine: preliminary clinical results

2002 ◽  
Vol 97 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Kevin T. Foley ◽  
Sanjay K. Gupta
Keyword(s):  
Lumbar Spine ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Posterior Fixation ◽  
Content Type ◽  
Insertion Device ◽  
Lumbar Pedicle ◽  
Fine Print

Object. Standard techniques for pedicle screw fixation of the lumbar spine involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine. Methods. An existing multiaxial lumbar pedicle screw system was modified to allow screws to be placed percutaneously by using an extension sleeve that permits remote manipulation of the polyaxial screw heads and remote engagement of the screw-locking mechanism. A unique rod-insertion device was developed that linked to the screw extension sleeves, allowing for a precut and -contoured rod to be placed through a small stab wound. Because the insertion device relies on the geometrical constraint of the rod pathway through the screw heads, minimal manipulation is required to place the rods in a standard submuscular position, there is essentially no muscle dissection, and the need for direct visual feedback is avoided. Twelve patients (six men and six women) who ranged in age from 23 to 68 years underwent pedicle screw fixation in which the rod-insertion device was used. Spondylolisthesis was present in 10 patients and osseous nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5—S1, three at L4–5, and one at L2–3), and two underwent two-level fusions (one from L3–5 and the other from L4—S1). The follow-up period ranged from 10 to 19 months (mean 13.8 months). Conclusions. Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience involving the use of this device has been promising.

One-stage posterior decompression and reconstruction of the cervical spine by using pedicle screw fixation systems

1999 ◽  
Vol 90 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Kuniyoshi Abumi ◽  
Kiyoshi Kaneda ◽  
Yasuhiro Shono ◽  
Masanori Fujiya
Keyword(s):  
Cervical Spine ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Spinal Cord Tumor ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Posterior Decompression ◽  
Content Type ◽  
One Stage ◽  
Fine Print

Object. This retrospective study was conducted to analyze the results of one-stage posterior decompression and reconstruction of the cervical spine by using pedicle screw fixation systems in 46 patients. Methods. Causes of cervical myelopathy in these 46 patients included spondylosis or ossification of the posterior longitudinal ligament, rheumatoid arthritis, metastatic or primary vertebral tumors, cervical spinal injuries, and spinal cord tumor. Thirty-three patients underwent this one-stage procedure as primary surgery. In the remaining 13 patients who had previously undergone laminectomies, the one-stage procedure was performed as salvage surgery. Cervical pedicle screws were inserted into the pedicles after probing and tapping. Graft bone was placed on the bilateral lateral masses, and pedicle screws were interconnected longitudinally by either plates or rods. Postoperatively, 26 patients showed improved neurological status (at least one grade improvement on Frankel's functional classification). There were no cases of neurological deterioration postoperatively. Solid bony fusion was obtained in all patients, except in seven patients with metastatic tumor who did not receive bone grafts. Correction of kyphosis was satisfactory. Postoperative radiological evaluation revealed that 10 (5.3%) of 190 screws inserted into the cervical vertebrae had perforated the cortex of the pedicles; however, no neurovascular complications were caused by the perforations. Conclusions. The pedicle screw fixation procedure, which does not require the lamina to be used as a stabilizing anchor, has proven to be valuable when performing one-stage posterior decompressive and reconstructive surgery in the cervical spine. The risk to neurovascular structures in this procedure, however, cannot be completely eliminated. Thorough knowledge of local anatomy and application of established surgical techniques are essential for this procedure.

Thoracic transfacet pedicle screw fixation: a new instrumentation technique

2005 ◽  
Vol 3 (3) ◽  
pp. 224-229 ◽  
Author(s):  
Atilla Akbay ◽  
Serkan İnceoğlu ◽  
Ryan Milks ◽  
Richard Schlenk ◽  
Selcuk Palaoglu ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screws ◽  
Transverse Process ◽  
Pedicle Screw Fixation ◽  
Content Type ◽  
Thoracic Surgical Procedures ◽  
Flexion Extension ◽  
Fixation Techniques ◽  
Fine Print

Object. Pedicle screw instrumentation of the thoracic spine remains technically challenging. Transverse process and costotransverse screw fixation techniques have been described as alternatives to pedicle screw fixation (PSF). In this study, the authors introduce thoracic transfacet PSF and compare its experimental biomechanical results with those of standard PSF in short-term cyclic loading in cadaveric thoracic specimens. Methods. Specimens were tested intact for six cycles at compressive loads of 250 N offset by 1 cm along appropriate axes to induce flexion, extension, and left and right lateral bending. The specimens were then fixed with either a pedicle screw/rod construct or transfacet pedicle screws and retested in the same fashion. After this sequence, specimens were loaded until failure in flexion mode at a rate of 5 mm/minute was observed. Both fixation constructs provided significantly greater stiffnesses than that demonstrated when the specimen was intact (p < 0.05, two-way analysis of variance). Additionally, the two constructs were statistically equivalent in terms of stiffness and load-to-failure values (p < 0.05, two-tailed nonpaired t-test). The only difference observed was that the low midthoracic region (T7–9) was biomechanically weaker than the upper midthoracic and lower thoracic areas in flexion after the destabilization and instrumentation-augmented stabilization procedures. Conclusions. In selected thoracic surgical procedures, transfacet PSF may, after analysis of long-term biomechanical data, potentially become a reasonable alternative to conventional PSF.

Anterior transvertebral interbody cage with posterior transdiscal pedicle screw instrumentation for high-grade spondylolisthesis

2006 ◽  
Vol 20 (3) ◽  
pp. 1-7 ◽  
Author(s):  
Will Forest Beringer ◽  
Jean-Pierre Mobasser ◽  
Dean Karahalios ◽  
Eric Alfred Potts
Keyword(s):  
Pedicle Screw ◽  
Degenerative Spondylolisthesis ◽  
Pedicle Screws ◽  
Pedicle Screw Fixation ◽  
Technical Note ◽  
Slip Angle ◽  
Fibular Graft ◽  
High Grade ◽  
Shear Forces

✓Adult high-grade degenerative spondylolisthesis represents the extreme end of the spectrum for spondylolisthesis and is consequently rarely encountered. Surgical management of high-grade spondylolisthesis requires constructs capable of resisting the shear forces at the slipped L5–S1 interspace. The severity of the slip, sacral inclination, and slip angle may make conventional approaches to 360° fusion difficult or hazardous. Transdiscal pedicle screw fixation, transvertebral fibular graft fusion, and transvertebral cage fixation are techniques that have been developed to establish anterior column load sharing and to resist shear forces at the L5–S1 interspace, given the anatomical constraints accompanying high-grade spondylolisthesis. In this technical note the authors describe the procedure for implanting an in situ anterior L5–S1 transvertebral cage and performing L4–5 anterior lumbar interbody fusion, followed by placement of posterior S1–L5 vertebral body transdiscal pedicle screws for management of high-grade spondylolisthesis.

Application of frameless stereotaxy to pedicle screw fixation of the spine

1995 ◽  
Vol 83 (4) ◽  
pp. 641-647 ◽  
Author(s):  
Iain H. Kalfas ◽  
Donald W. Kormos ◽  
Michael A. Murphy ◽  
Rick L. McKenzie ◽  
Gene H. Barnett ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Spinal Surgery ◽  
Screw Fixation ◽  
Ct Images ◽  
Pedicle Screw Fixation ◽  
Lumbosacral Spine ◽  
Frameless Stereotaxy ◽  
Content Type ◽  
Screw Length ◽  
Fine Print

✓ Interactive frameless stereotaxy has been successfully applied to intracranial surgery. It has contributed to the improved localization of deep-seated brain lesions and has demonstrated a potential for reducing both operative time and morbidity. However, it has not been as effectively applied to spinal surgery. The authors describe the application of frameless stereotactic techniques to spinal surgery, specifically pedicle screw fixation of the lumbosacral spine. Preoperative axial computerized tomography (CT) images of the appropriate spinal segments are obtained and loaded onto a high-speed graphics supercomputer workstation. Intraoperatively, these images can be linked to the appropriate spinal anatomy by a sonic localization digitizer device that is interfaced with the computer workstation. This permits the surgeon to place a pointing device (sonic wand) on any exposed spinal bone landmark in the operative field and obtain multiplanar reconstructed CT images projected in near-real time on the workstation screen. The images can be manipulated to assist the surgeon in determining the proper entry point for a pedicle screw as well as defining the appropriate trajectory in the axial and sagittal planes. It can also define the correct screw length and diameter for each pedicle to be instrumented. The authors applied this device to the insertion of 150 screws into the lumbosacral spines of 30 patients. One hundred forty-nine screws were assessed to be satisfactorily placed by postoperative CT and plain film radiography. In this report the authors discuss their use of this device in the clinical setting and review their preliminary results of frameless stereotaxy applied to spinal surgery. On the basis of their findings, the authors conclude that frameless stereotactic technology can be successfully applied to spinal surgery.

Outcome analysis for adults with spondylolisthesis treated with posterolateral fusion and transpedicular screw fixation

1997 ◽  
Vol 86 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Charles L. Schnee ◽  
Andrew Freese ◽  
Lee V. Ansell
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Fusion Rate ◽  
Pedicle Screw Fixation ◽  
Outcome Analysis ◽  
Low Grade ◽  
Content Type ◽  
Poor Outcomes ◽  
Transpedicular Screw Fixation ◽  
Fine Print

✓ The outcomes of 52 adult patients with symptomatic low-grade spondylolisthesis treated with autologous posterolateral arthrodesis and pedicle screw fixation were retrospectively reviewed. Although a 90% rate of successful fusion was obtained using this technique, only 60% of patients were considered to have good outcomes. Treatment failures consisted mostly of back pain and were not predicted by preoperative symptoms. Compensation claims and smoking had very significant adverse impacts on both employment and pain results despite high fusion rates, particularly in patients under the age of 55 years. Overall, patients who required more than one operation demonstrated poor outcomes compared to those who only needed one. However, patients with at least two prior operations or preoperative pseudoarthrosis fared particularly poorly, whereas those who had undergone only one prior surgery and had no attendant compensation issue reported good results. A trend toward poor outcome was observed in patients with postlaminectomy spondylolisthesis, versus those with isthmic or degenerative etiologies. Gender did not exert an impact on outcome. The authors conclude that autologous posterolateral arthrodesis combined with pedicle screw fixation resulted in a high fusion rate, and contributed to successful outcomes in the treatment of certain subgroups of adults with spondylolisthesis. In the absence of other risk factors, patients may obtain significant benefit from surgery despite older age and a single failed operation. Careful patient selection appears critical in predicting the maximum benefit from this technique.

Removal of broken pedicle screws

2001 ◽  
Vol 95 (1) ◽  
pp. 150-151 ◽  
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.

Three-dimensional fluoroscopy-guided percutaneous thoracolumbar pedicle screw placement

2003 ◽  
Vol 99 (3) ◽  
pp. 324-329 ◽  
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.

Clinical outcomes and complications associated with pedicle screw fixation—augmented lumbar interbody fusion

2004 ◽  
Vol 1 (3) ◽  
pp. 261-266 ◽  
Author(s):  
Dennis J. Rivet ◽  
David Jeck ◽  
James Brennan ◽  
Adrian Epstein ◽  
Carl Lauryssen
Keyword(s):  
Carbon Fiber ◽  
Pedicle Screw ◽  
Interbody Fusion ◽  
Screw Fixation ◽  
Pedicle Screw Fixation ◽  
Lumbar Interbody Fusion ◽  
Content Type ◽  
Repeated Surgery ◽  
Fine Print

Object. The authors conducted a prospective study to evaluate the clinical and radiological outcomes and complications associated with uni- and bilateral transforaminal lumbar interbody fusion (TLIF) performed using carbon fiber Brantigan I/F Cages and pedicle screw fixation. Methods. Forty-two consecutive patients who had undergone uni- or bilateral TLIF between February 1999 and July 2000 were prospectively evaluated. Clinical outcome was graded using a modified Prolo Scale, the McGill Pain Index Scale, a follow-up questionnaire, and charts. An independent radiologist assessed radiological outcomes. All patients were followed for at least 1 year. Based on Prolo Scale scores, an excellent or good 1-year outcome was achieved in 73% of patients; 90% of patients responded that they would undergo the procedure again. At 1 year, radiographic fusion was demonstrated in 74% and was statistically related to clinical outcome (p < 0.05). There were no deaths or major hardware failures. Complications requiring repeated surgery included one case of cerebrospinal fluid (CSF) leakage and one case in which the hemovac drain was retained. There were four cases involving minor wound infections, eight involving CSF leaks, and none requiring repeated surgery. On routine follow-up radiography one pedicle screw was found to be broken; the patient remained asymptomatic and fusion occurred. Conclusions. Unilateral and bilateral TLIF involving placement of carbon fiber cages and pedicle screw fixation are effective treatment options in patients with indications for lumbar arthrodesis. The procedures result in acceptable rates of fusion and clinical success, and a minimal incidence of morbidity when performed by an experienced surgeon.

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