Cortical Trajectory Pedicle Screw Research Articles

Minimally invasive lumbar endoscopic discectomy and interbody fusion with percutaneous posterior cortical-trajectory pedicle screw and rod stabilization – A case series

Minimally invasive (MIS) lumbar endoscopic discectomy and MIS interbody cage fusion, augmented by a posterior percutaneous pedicle screw and rod instrumented stabilization is increasing in popularity for the surgical management of degenerative lumbar pathology. Minimally invasive techniques are favored as they entail less muscle and tissue dissection, shorter recovery time, less blood loss, and shorter hospital length of stay compared to conventional open techniques. We provide a novel description of performing an endoscopic discectomy with interbody cage placement followed by minimal access posterior approach cortical-trajectory pedicle screw and rod stabilization. MethodsWe performed a retrospective chart review of five patients who underwent a MIS single level lumbar endoscopic discectomy and interbody fusion augmented by posterior cortical-trajectory pedicle screw and rod instrumented stabilization. Surgical techniques are discussed in detail and clinical outcomes for each case were reviewed. ResultsWe present five patients who underwent MIS endoscopic discectomy and interbody cage fusion augmented by percutaneous cortical-trajectory pedicle screw and rod instrumented stabilization. All patients demonstrated improvement in pain postoperatively with only one relevant complication. ConclusionsThe cases reviewed illustrate the feasibility of performing MIS endoscopic discectomy and interbody cage fusion augmented by percutaneous cortical-trajectory pedicle screw and rod instrumented stabilization for select patient populations.

MORPHOMETRY OF THE POSITIONING OF CORTICAL TRAJECTORY PEDICLE SCREWS IN BRAZILIANS

ABSTRACT Objective Morphometric study of the positioning of the cortical trajectory pedicle screw in the lumbar spine of Brazilian patients of different sexes and ages, through the use of computed tomography images, in order to obtain more reliable data about cortical screw insertion and the variations observed, providing assistance for a safer, more effective approach with fewer complications. Methods Selection of 100 patients from a database, alternating by sex, measuring the length, diameter, cephalic angulation, and lateral angulation of the vertebrae from L1 to L5. Results Statistically significant measurements were obtained for the four different parameters in relation to sex. The mean age was 56, with a minimum of 20 and a maximum of 87 years. The L4 and L5 screws showed a reduction in relation to the other levels, while the width showed a progressive increase starting at L3. Lateral angulation was the parameter with the least variation among the levels, while there was greater variation and a reduction from L4 to L5 in cephalic angulation. Conclusion Statistically significant results were obtained for length, diameter, lateral and cephalic angulation. Sex was a significant factor in spine surgery instrumentation using the cortical trajectory pedicle screw technique. Level of evidence I; Diagnostic study (investigation of an examination for diagnosis).

Spinal instrumentation in infants, children, and adolescents: a review.

OBJECTIVEThe evolution of pediatric spinal instrumentation has progressed in the last 70 years since the popularization of the Harrington rod showing the feasibility of placing spinal instrumentation into the pediatric spine. Although lacking in pediatric-specific spinal instrumentation, when possible, adult instrumentation techniques and tools have been adapted for the pediatric spine. A new generation of pediatric neurosurgeons with interest in complex spine disorder has pushed the field forward, while keeping the special nuances of the growing immature spine in mind. The authors sought to review their own experience with various types of spinal instrumentation in the pediatric spine and document the state of the art for pediatric spine surgery.METHODSThe authors retrospectively reviewed patients in their practice who underwent complex spine surgery. Patient demographics, operative data, and perioperative complications were recorded. At the same time, the authors surveyed the literature for spinal instrumentation techniques that have been utilized in the pediatric spine. The authors chronicle the past and present of pediatric spinal instrumentation, and speculate about its future.RESULTSThe medical records of the first 361 patients who underwent 384 procedures involving spinal instrumentation from July 1, 2007, to May 31, 2018, were analyzed. The mean age at surgery was 12 years and 6 months (range 3 months to 21 years and 4 months). The types of spinal instrumentation utilized included occipital screws (94 cases); C1 lateral mass screws (115 cases); C2 pars/translaminar screws (143 cases); subaxial cervical lateral mass screws (95 cases); thoracic and lumbar spine traditional-trajectory and cortical-trajectory pedicle screws (234 cases); thoracic and lumbar sublaminar, subtransverse, and subcostal polyester bands (65 cases); S1 pedicle screws (103 cases); and S2 alar-iliac/iliac screws (56 cases). Complications related to spinal instrumentation included hardware-related skin breakdown (1.8%), infection (1.8%), proximal junctional kyphosis (1.0%), pseudarthroses (1.0%), screw malpositioning (0.5%), CSF leak (0.5%), hardware failure (0.5%), graft migration (0.3%), nerve root injury (0.3%), and vertebral artery injury (0.3%).CONCLUSIONSPediatric neurosurgeons with an interest in complex spine disorders in children should develop a comprehensive armamentarium of safe techniques for placing rigid and nonrigid spinal instrumentation even in the smallest of children, with low complication rates. The authors' review provides some benchmarks and outcomes for comparison, and furnishes a historical perspective of the past and future of pediatric spine surgery.

Early clinical results with cortically based pedicle screw trajectory for fusion of the degenerative lumbar spine

This study reviews the outcomes and revision rates of degenerative lumbar fusion surgery using cortical trajectory pedicle screws in lieu of traditional pedicle screw instrumentation. Pedicle screw fixation can be a challenge in patients with low bone mineral density. Wide posterior approaches to the lumbar spine exposing lateral to the facet joints and onto transverse processes causes an additional degree of muscular damage and blood loss not present with a simple laminectomy. A cortical bone trajectory pedicle screw has been proposed as an alternative to prevent screw pullout and decrease the morbidity associated with the wide posterior approach to the spine. We present a series of eight consecutive patients using a cortical bone trajectory instead of traditional pedicle screw fixation for degenerative conditions of the lumbar spine. A retrospective review of our institutional registry data identified eight patients who had cortical screws placed with the assistance of O-arm Stealth navigation (Medtronic Sofamor Danek, Memphis, TN, USA) from 2010–2013. We analyzed the need for revision, the maintenance of reduction and the incidence of screw pullout or breakage. Our review demonstrated that two of eight patients were revised at an average of 12months. The reasons for these revisions were pseudarthrosis and caudal adjacent segment failure. All patients who were revised had frank screw loosening. We present early clinical results of a new technique that has been shown to have a better fixation profile in laboratory testing. Our less than favorable early clinical results should be interpreted with caution and highlight important technical issues which should be considered.

Minimally invasive PLIF with divergent, cortical trajectory pedicle screws.

Minimally invasive PLIF with divergent, cortical trajectory pedicle screws.

Cortical and Standard Trajectory Pedicle Screw Fixation Techniques in Stabilizing Multisegment Lumbar Spine with Low Grade Spondylolisthesis.

Cortical screw (CS) fixation has been recently proposed as an alternative to the standard pedicle screw (PS) fixation technique. Biomechanical studies involving individual screw pullout and single level motion segment stabilization showed comparable performance of both techniques. However, whether this new fixation technique can be applied to the stabilization of multilevel lumbar segments with significant destabilization has been unclear. To compare stability of CS fixation to the traditional PS fixation in an unstable 3 level spondylolisthesis model. This is a biomechanical study comparing cortical trajectory pedicle screw fixation to traditional trajectory pedicle screw fixation in an unstable cadaveric model using nondestructive flexibility test. Eight fresh frozen cadaveric lumbar spines (T12- S1) were obtained. After intact baseline testing, a 3-level lowgrade spondylolisthesis was simulated at the L1-4. Each specimen was instrumented with the PS and CS fixation systems. Standard nondestructive flexibility test was performed. Range of motion at each level was compared between the constructs during flexion-extension, lateral bending, and axial rotation. The destabilization model significantly increased the ROM in all planes (P<0.05). Both fixation techniques provided significant reduction in the ROM (P<0.05). There was no significant difference in ROM between the PS and CS groups in any of planes (P>0.05). Cortical trajectory pedicle screw fixation provided stabilization to multilevel lumbar segment with low-grade spondylolisthesis comparable to the standard trajectory pedicle screw construct.