A Comparative Biomechanical Analysis of Stand Alone Versus Facet Screw and Pedicle Screw Augmented Lateral Interbody Arthrodesis: An In Vitro Human Cadaveric Model.

Study Design: Cadaveric biomechanical study.

Objective: To investigate the kinematic response of a stand-alone lateral lumbar interbody cage compared with supplemental posterior fixation with either facet or pedicle screws after lateral discectomy.

Summary Of Background Data: Lateral interbody fusion is a promising minimally invasive fixation technique for lumbar interbody arthrodesis.

Epidural application of spinal instrumentation particulate wear debris: a comprehensive evaluation of neurotoxicity using an in vivo animal model.

Object: The introduction and utilization of motion-preserving implant systems for spinal reconstruction served as the impetus for this basic scientific investigation. The effect of unintended wear particulate debris resulting from micromotion at spinal implant interconnections and bearing surfaces remains a clinical concern. Using an in vivo rabbit model, the current study quantified the neural and systemic histopathological responses following epidural application of 11 different types of medical-grade particulate wear debris produced from spinal instrumentation.

Comparative in vitro biomechanical analysis of a novel posterior cervical fixation technique versus conventional posterior-based constructs.

Study Design: Comparative in vitro, cadaveric biomechanical study.

Objective: To compare the kinematic response of a new posterior cervical midline surgical technique versus that of conventional fixation techniques.

Summary Of Background Data: A new method was designed using alternating bilateral intralaminar screws connected with a single midline rod.

Adjacent-level range of motion and intradiscal pressure after posterior cervical decompression and fixation: an in vitro human cadaveric model.

Study Design: This in vitro human cadaveric study measured adjacent-level kinematics after posterior cervical decompression and fixation.

Objective: Quantify adjacent-level changes in range of motion (ROM) and intradiscal pressure after posterior cervical decompression and fixation.

Summary Of Background Data: Optimal length of instrumentation after posterior decompression is unclear.

Multidirectional flexibility of the spine following posterior decompressive surgery after single-level cervical disc arthroplasty: an in vitro biomechanical investigation.

Study Design: In vitro human cadaveric biomechanical study.

Objective: This study quantifies the multidirectional flexibility of the spine following laminoplasty and laminectomy after cervical disc arthroplasty.

Summary Of Background Data: Posterior decompressive surgery may be used to treat recurrence of myeloradiculopathy following disc arthroplasty.

The effect of spinal instrumentation on kinematics at the cervicothoracic junction: emphasis on soft-tissue response in an in vitro human cadaveric model.

Object: Thoracic pedicle screw instrumentation is often indicated in the treatment of trauma, deformity, degenerative disease, and oncological processes. Although classic teaching for cervical spine constructs is to bridge the cervicothoracic junction (CTJ) when instrumenting in the lower cervical region, the indications for extending thoracic constructs into the cervical spine remain unclear. The goal of this study was to determine the role of ligamentous and facet capsule (FC) structures at the CTJ as they relate to stability above thoracic pedicle screw constructs.

Autologous growth factors versus autogenous graft for anterior cervical interbody fusion: an in vivo caprine model.

Object: Using an in vivo caprine model, authors in this study compared the efficacy of autologous growth factors (AGFs) with autogenous graft for anterior cervical interbody arthrodesis.

Methods: Fourteen skeletally mature Nubian goats were used in this study and followed up for a period of 16 weeks postoperatively. Anterior cervical interbody arthrodesis was performed at the C3-4 and C5-6 vertebral levels.

Surgical management of two- versus three-column injuries of the cervicothoracic junction: biomechanical comparison of translaminar screw and pedicle screw fixation using a cadaveric model.

Study Design: An in vitro cadaveric biomechanical study.

Objective: To determine the stability of translaminar screws compared to pedicle screws at T1-T2 for constructs bridging the cervicothoracic junction.

Summary Of Background Data: Instrumented fixation of the cervicothoracic junction is challenging both biomechanically, due to the transition from the mobile cervical to the rigid thoracic spine, and technically, due to the anatomic constraints of the T1-T2 pedicles.

Biomechanical evaluation of a posterolateral lumbar disc arthroplasty device: an in vitro human cadaveric model.

Study Design: This in vitro analysis defines biomechanical properties of the Triumph Lumbar Disc (TLD) for posterolateral lumbar disc arthroplasty.

Objectives: To quantify segmental kinematics afforded by the TLD, determine whether intervertebral positional changes of the device affect spinal kinematics, and compare kinematics following TLD reconstruction with historical CHARITE data.

Summary Of Background Data: As an alternative to arthrodesis, total disc arthroplasty serves to restore the biomechanical properties of the spine.

Preclinical evaluation of the Dynesys posterior spinal stabilization system: a nonhuman primate model.

Background Context: Posterior dynamic spinal stabilization systems are intended to restore near-normal biomechanical function of the spine without inducing unnatural stresses to the spinal elements or eliciting a histopathological response. These devices must resist loosening within the challenging biomechanical environment of the lumbar spine.

Purpose: To determine the biomechanical effects of the Dynesys dynamic stabilization system (Zimmer, Inc.

Biomechanical comparison of single- and two-level cervical arthroplasty versus arthrodesis: effect on adjacent-level spinal kinematics.

Background Context: The use of motion-preserving spinal implants versus conventional arthrodesis instrumentation systems, which stabilize operative segments, necessitates improved understanding of their effect on spinal kinematics and the biomechanically optimal method for surgical reconstruction.

Purpose: The primary objective of this study was to measure operative- and adjacent-level kinematics after single- and two-level cervical arthroplasty and compare them with those after anterior cervical arthrodesis. A secondary objective was to locate the centers of intervertebral rotation at the operative and adjacent levels after arthroplasty and compare them to those after arthrodesis.

Biomechanical comparison of iliac screws versus interbody femoral ring allograft on lumbosacral kinematics and sacral screw strain.

Study Design: This study evaluates the effect of iliac screw fixation versus interbody femoral ring allograft (FRA) on lumbosacral kinematics and sacral screw strain in long segment instrumentations.

Objective: (1) Quantify kinematic properties of 3 lumbosacral fixation techniques; (2) Evaluate sacral screw strain as instrumented levels extend cephalad; and (3) Determine whether iliac screws or FRA biomechanically protect sacral screws.

Summary Of Background Data: High failure rates at the lumbosacral junction have been reported with long posterior instrumentation ending with S1 pedicle screws.

Comparative fixation methods of cervical disc arthroplasty versus conventional methods of anterior cervical arthrodesis: serration, teeth, keels, or screws?

Object: Using a synthetic vertebral model, the authors quantified the comparative fixation strengths and failure mechanisms of 6 cervical disc arthroplasty devices versus 2 conventional methods of cervical arthrodesis, highlighting biomechanical advantages of prosthetic endplate fixation properties.

Methods: Eight cervical implant configurations were evaluated in the current investigation: 1) PCM Low Profile; 2) PCM V-Teeth; 3) PCM Modular Flange; 4) PCM Fixed Flange; 5) Prestige LP; 6) Kineflex/C disc; 7) anterior cervical plate + interbody cage; and 8) tricortical iliac crest. All PCM treatments contained a serrated implant surface (0.

Bioactive titanium calcium phosphate coating for disc arthroplasty: analysis of 58 vertebral end plates after 6- to 12-month implantation.

Background Context: From a biomechanical perspective, the successful outcome of total disc replacement is largely based on the mechanisms of acute fixation obtained at the index procedure and the extent of porous biological osseointegration at the prosthesis-bone interface, ensuring long-term device fixation.

Purpose: The present retrospective investigation quantifies the extent of porous osseointegration in cervical and lumbar disc arthroplasty implants containing a bioactive titanium/calcium phosphate coating.

Study Design: Based on radiographic analysis and quantitative histomorphometry, the study was designed to determine the extent of porous osseointegration and whether osseointegration was affected by arthroplasty implant position.

Revision strategies for single- and two-level total disc arthroplasty procedures: a biomechanical perspective.

Background Context: The utilization of motion-preserving implants versus conventional instrumentation systems, which stabilize the operative segments, necessitates improved understanding of their comparative biomechanical properties and optimal biomechanical method for surgical revision.

Purpose: Using an in vitro human cadaveric model, the primary objective was to compare the multidirectional flexibility properties of single- versus two-level total disc arthroplasty procedures and determine the acute in vitro biomechanical characteristics of two methods of surgical revision-posterior transpedicular instrumentation alone or circumferential spinal arthrodesis.

Study Design: This in vitro biomechanical study was undertaken to compare the multidirectional flexibility kinematics of single- versus two-level lumbar total disc arthroplasty reconstructions using an in vitro model.

Ceramic granules enhanced with B2A peptide for lumbar interbody spine fusion: an experimental study using an instrumented model in sheep.

Object: New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep.

Methods: Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep.

Regeneration of a spinal ligament after total lumbar disk arthroplasty in primates.

Total disk arthroplasty (TDA) is a new procedure that replaces the intervertebral disk space with an artificial motion segment and necessitates the resection of the anterior longitudinal ligament (ALL). We assessed whether a collagen-based graft made from porcine small-intestine submucosa (SIS) can be used as a regenerative scaffold to restore the function and structure of the ALL in the lumbar spine. A total of 10 mature male baboons underwent TDA at L5-L6 using one of two treatments: (1) TDA only (n = 5) or (2) TDA combined with SIS (n = 5).

Evaluation of total disc arthroplasty: a canine model.

The study reported here was designed to examine the biomechanical and histopathologic properties of total disc arthroplasty (TDA) using a canine model. Thirty-seven dogs were divided into 3 groups (intact spine, fusion, TDA) and sacrificed either at study commencement or at 3 months. Results showed progressive fusion from 0 to 3 months in the fusion group.

Influence of a platelet concentrate on prosthetic bone ingrowth in a rabbit model.

Recent studies have shown that an increase in bone ingrowth by addition of osteogenic growth factors can reduce micro motion and gross implant motion and contribute to joint implant stability through osseointegration. Platelet-rich plasma (PRP) has the potential to provide growth factors that may be conducive to osteointegration at the bone-implant interface. This study analyzed the influence of PRP on bone ingrowth upon a beaded metal implant in distal femurs of 22 rabbits.

A comparative biomechanical analysis of spinal instability and instrumentation of the cervicothoracic junction: an in vitro human cadaveric model.

Objective: Stabilization of the cervicothoracic junction is challenging but commonly required in patients with traumatic, neoplastic, congenital, and postlaminectomy conditions. Although extensive research has been performed on stabilization of the cervical spine, there remains a paucity of published data on instrumentation at the cervicothoracic junction. Using 2-column, 3-column, and corpectomy instability models, a biomechanical analysis was performed on the effects of increasing the number of posterior segmental fixation points and/or anterior column reconstruction at the cervicothoracic junction.

Biomechanical analysis of rotational motions after disc arthroplasty: implications for patients with adult deformities.

Study Design: An anatomic and biomechanical bench-top basic scientific comparative analysis to determine the appropriateness of total disc replacement (TDR) in a lumbar spine with scoliotic tendencies.

Objectives: Only limited data are currently available studying the application of disc replacement adjacent to scoliosis fusions. Theoretically, motion preservation should help delay the continuum of lumbar degeneration adjacent to scoliosis fusions and rotationally unstable lumbar segments.

A comparison of retraction pressure during anterior cervical plate surgery and cervical disc replacement: a cadaveric study.

Background Context: Dysphagia is a well-recognized complication after anterior cervical discectomy and fusion, observed in as high as 50% of cases by videofluoroscopic evaluation postoperatively. Esophageal injury due to surgical retraction is a complication due to which swallowing difficulties may ensue. There are limited published data evaluating the effect of soft tissue retraction on intraesophageal pressures during anterior cervical instrumentation procedures.

Porous coated motion cervical disc replacement: a biomechanical, histomorphometric, and biologic wear analysis in a caprine model.

Study Design: The biomechanical, histopathologic, and histomorphometric characteristics of cervical disc replacement were assessed in a caprine animal model.

Objective: To investigate the biomechanical, porous ingrowth, and histopathologic characteristics of the Porous Coated Motion (PCM) Cervical Disc replacement (Cervitech, Inc., Rockaway, NJ).

Adjacent level intradiscal pressure and segmental kinematics following a cervical total disc arthroplasty: an in vitro human cadaveric model.

Study Design: In vitro investigation of cervical adjacent level intradiscal pressures (IDPs) following a total disc replacement arthroplasty.

Objectives: The current in vitro study was undertaken to compare adjacent level IDPs and operative level kinematics following a cervical arthroplasty versus an arthrodesis procedure.

Summary Of Background Data: Clinical data indicate the incidence of symptomatic transition syndrome to be as high as 3% annually following a cervical interbody arthrodesis.

General principles of total disc replacement arthroplasty: seventeen cases in a nonhuman primate model.

Study Design: To investigate the biomechanical, histochemical, and biologic ingrowth characteristics of two different lumbar disc prostheses-AcroFlex (DePuy-AcroMed) and the SB Charitè (DePuy-AcroMed)-for total disc replacement arthroplasty.

Methods: A total of 17 mature baboons (n = 17, Papio cynocephalus) underwent L5-L6 total disc replacement procedures. The AcroFlex device (n = 10 levels) consisted of sintered titanium beaded ingrowth surfaces, bound together by a hexene-based polyolefin rubber core.