Cage Implantation Research Articles

Implantation of the anterior atlantoaxial lateral mass intervertebral cage using the transoral approach.

The purpose of this study was to evaluate the possibility of implanting the anterior atlantoaxial lateral mass intervertebral cage, a new type of fixation, by the transoral approach. This study examined the possibility of implantation invivo by the quantitative measurement on the dry atlantoaxial bone and implantation of the anterior atlantoaxial lateral mass intervertebral cage in specimens. Anterior atlantoaxial lateral mass intervertebral cages were implanted in 10 atlantoaxial joint specimens using the transoral approach. Eight anatomical parameters (width, the thickness, ordinates, abscissas, and declination angles of the mass) from each of the 30 dry atlas and axis bone specimens were measured. These parameters determined the size and the design of the cage and the way of implantation. The course of the vertebral artery forms the safe boundary for transoral surgery. The shape of the area of work exposure was an inverted trapezoid. In specimens, the anterior atlantoaxial lateral mass intervertebral cages could be successfully implanted using the transoral approach. The parameters of the human atlantoaxial lateral masses exposed anteriorly showed that there was enough space, for the safe anterior implantation of the cage. The surgery using the transoral atlantoaxial reduction and plate makes possible the implantation of the anterior cage. The implantation of anterior atlantoaxial lateral mass intervertebral cage through transoral approach is possible.

Titanium versus polyetheretherketone implants for vertebral body replacement in the treatment of 77 thoracolumbar spinal fractures.

Background:Titanium and polyetheretherketone (PEEK) implants have been used in spinal surgery with low rejection rates. Compared to titanium, PEEK has many advantages, including a density more similar to that of bone, radiolucency, and a lack of artifacts in computed tomography (CT) and magnetic resonance imaging (MRI). In this study, we evaluated the effectiveness of PEEK cages as an alternative to titanium for bone fusion after fractures of the thoracolumbar spine. We also propose a classification to the impaction index.Methods:We evaluated 77 patients with fractures of the thoracic or lumbar spine who were treated by anterior fixation with titanium cages (TeCorp®) in 46 (59.7%) patients or PEEK (Verte-stak®) in 31 (40.3%) patients from 2006 to 2012 (Neurological Hospital of Lyon).Results:The titanium group achieved 100% fusion, and the PEEK group achieved 96.3% fusion. The titanium systems correlated with higher impact stress directed toward the lower and upper plateaus of the fused vertebrae; there were no nonunions for those treated with titanium group. Nevertheless, there was only one in the PEEK group. There was no significant difference in the pain scale outcomes for patients with ±10 degrees of the sagittal angle. Statistically, it is not possible to associate the variation of sagittal alignment or the impaction with symptoms of pain. The complication rate related to the implantation of cages was low.Conclusions:Titanium and PEEK are thus equally effective options for the reconstruction of the anterior column. PEEK is advantageous because its radiolucency facilitates the visualization of bone bridges.

Stand-Alone Anterior Cervical Decompression and Fusion in Three Levels with Peek Cages: A Possible Satisfactory Alternative

Anterior cervical decompression and fusion (ACDF) remains the gold standard for subaxial degeneration of anterior elements. By multilevel stenosis corpectomy or instrumentation with screws and plate are supported. Their potential complications, though, should be reckoned. The use of polyetheretherketone (PEEK) cages packed with demineralized bone matrix (DBM) alone can provide good fusion rates and clinical improvement even in cases of three levels degeneration. The purpose of this paper is to present retrospectively the outcomes of 15 patients with cervical stenosis in three levels treated with cage implantation reviewing the relevant literature, too.

First clinical results of minimally invasive vector lumbar interbody fusion (MIS-VLIF) in spondylodiscitis and concomitant osteoporosis: a technical note.

First description of MIS-VLIF, a minimally invasive lumbar stabilization, to evaluate its safety and feasibility in patients suffering from weak bony conditions (lumbar spondylodiscitis and/or osteoporosis). After informed consent, 12 patients suffering from lumbar spondylodiscitis underwent single level MIS-VLIF. Eight of them had a manifest osteoporosis, either. Pre- and postoperative clinical status was documented using numeric rating scale (NRS) for leg and back pain. In all cases, the optimal height for the cage was preoperatively determined using software-based range of motion and sagittal balance analysis. CT scans were obtained to evaluate correct placement of the construct and to verify fusion after 6months. Since 2013, 12 patients with lumbar pyogenic spondylodiscitis underwent MIS-VLIF. Mean surgery time was 169±28min and average blood loss was less than 400ml. Postoperative CT scans showed correct placement of the implants. Eleven patients showed considerable postoperative improvement in clinical scores. In one patient, we observed screw loosening. After documented bony fusion in the CT scan, the fixation system was removed in two cases to achieve lower material load. The load-bearing trajectories (vectors) of MIS-VLIF are different from those of conventional coaxial pedicle screw implantation. The dorsally converging construct combines the heads of the dorsoventral pedicle screws with laminar pedicle screws following cortical bone structures within a small approach. In case of lumbar spondylodiscitis and/or osteoporosis, MIS-VLIF relies on cortical bony structures for all screw vectors and the construct does not depend on conventional coaxial pedicle screws in the presence of inflamed, weak, cancellous or osteoporotic bone. MIS-VLIF allows full 360° lumbar fusion including cage implantation via a small, unilateral dorsal midline approach.

Сervical microdiscectomy: method and surgical strategy

Objective. To implement the interlaminar lateral approach for extraction of herniated discs (HD) in the cervical spine. Materials and methods. During 2012–2015 in Regional psychoneurological hospital 56 patients with cervical HD were operated. There were 22 females, 36 males among them. Disc herniation at the CV–CVI level occurred in 21 cases, CVI–CVII in 20 cases. The main disease signs were cervicalgia, monoradiculopathy. Fifty patients with medial hernia were operated using anterior cervical microscopic discectomy approach to HP extraction and intervertebral cage implantation (PEEK material). Six patients with lateral hernia were operated using posterior interlaminar cervical microdiscectomy. Anterior approach was performed by a standard method using CODMAN retractor, high-speed drill Stryker TPS. The posterior interlaminar approach was performed using paramedian incision 3 cm, intermuscular approach to the posterior lateral mass and arch on the affected side with Medtronic Metrix system followed by interlaminectomy performed by high-speed drill not more than 1 cm that was rather enough for hernia extraction from under nerve root. Results. In all cases we managed to achieve the regression of radicular and cervicalgia syndromes. No complications were fixed during both surgical approaches. There was no difference observed in duration of surgical intervention using both methods, which was about (64±12) min. All patients were verticalized and activated in 3–4 hours after surgery. Conclusion. Cervical microdiscectomy is a standard method for cervical HD surgery. The posterior interlaminar approach is an effective method used for lateral herniations, especially sequestered ones. It promotes the preservation of intervertebral disc and reduction of the total cost of surgery due to no necessity to use the implants-prosthesis. We suppose the posterior cervical microdiscectomy of lateral, sequestered intervertebral disc herniations in cervical spine to become a standard method of treatment.

A radiographic analysis of cage positioning in lateral transpsoas lumbar interbody fusion

Direct Lumbar Interbody Fusion (DLIF) and eXtreme Lateral Interbody Fusion (XLIF) are the most common surgical platforms available for performing transpsoas spinal fusion but no study has been carried out to compare them. We evaluated 21 DLIF and 22 XLIF cage positions by measuring the distance between the posterior vertebral border and the centre of the cage normalised to the midsagittal length of the inferior end plate. We found that DLIF cages were significantly more anteriorly located than XLIF (0.65 vs 0.52, p=0.001) at L4-5, suggesting that XLIF would permit implantation of wider cages than DLIF.

Facet Fixation Combined with Lumbar Interbody Fusion: Comparative Analysis of Clinical Experience and A New Method of Surgical Treatment of Patients with Lumbar Degenerative Diseases

For the treatment of patients with degenerative diseases of the lumbar spine the technique of pedicle fixation is widespread, when after open decompression channel structure locking screws are introduced into the vertebral body through the back vertebra legs. We first used a fundamentally new way of fixing the rear using the facet-boards Cage «Facet Wedge», when posterior fixation is done by closing the facet joints with minimally invasive, percutaneous method. We have not found data on the clinical efficacy of facet fixation in scientific literature. To compare the clinical efficacy of facet fixation combined with interbody fusion in the treatment of patients with degenerative lumbar spine disease. The study included 145 patients who were divided into 2 groups. The study group with long-term observation included patients (n=100) who underwent a new method for lumbar fixation; the method comprises unilateral or bilateral implantation of titanium Cage «facet Wedge» in the joint space facet joint in combination with the anterior, lateral, and transforaminal interbody fusion. Clinical comparison group (n=45) included retrospectively recruited patients who were performed titanium pedicle screw installation after open decompression and interbody fusion posterior lumbar fixation. Dynamic observation and comprehensive evaluation of the treatment clinical results was carried out for 18 months after surgery. Cage facet installation technology is quite simple, universal for the stabilization of the rear of the complex after interbody fusion from the front, side, and rear access; and does not require the intraoperative application of expensive high-tech equipment. Comparative analysis of the main group showed significantly better results in terms of the duration of the operation [CG 125 (90; 140) min, the CCG 205 (160; 220) min; p=0.01], the volume of blood loss [CG 80 (70; 120) ml, CCG 350 (300; 550) ml; p=0.008], activation time [CG 2 (1; 2) days, 4 CCG (3; 5) days; p=0.02], length of hospitalization [CG 9 (10; 11) days, the CCG 13 (12; 15) days; p=0.03], the level of pain on a visual analog scale [CG 3 (2; 4) mm, CCG 15 (12; 18) mm; p=0.001], quality of life (by index Oswestry) [CG 8 (6; 8) points, the CCG 23 (20; 28) points, p=0.003], and labor rehabilitation [CG 3 (2; 6) months, CCG 9 (6; 12) months; p=0.0001]. The number of postoperative complications in group 1 was 13%, in the 2nd ― 31,1% (p=0,0012). The new method involves fixing the back with considerably less surgical trauma of paravertebral soft tissue that results in early activation of patients, reduction of stay in hospital period, and better functional recovery of patients. The application of facet fixation combined with interbody fusion in the treatment of patients with degenerative diseases of the lumbar spine allows achieving the best clinical outcomes and fewer postoperative complications during the short and long-term follow-up if compared with the traditional method of transpedicular stabilization. The combination of low-impact and reliability facet fixation techniques for posterior stabilization of the operated segment creates favorable conditions for the restoration of a functional condition of patients, full social and physical rehabilitation.

Outcomes Evaluation of Zero-Profile Devices Compared to Stand-Alone PEEK Cages for the Treatment of Three- and Four-Level Cervical Disc Disease

Background: Anterior cervical discectomy and fusion (ACDF) is a well-accepted treatment option for patients with cervical spine disease. Three- and four-level discectomies are known to be associated with a higher complication rate and lower fusion rate than single-level surgery. This study was performed to evaluate and compare zero-profile fixation and stand-alone PEEK cages for three- and four-level ACDF.Methods: Two cohorts of patients who underwent ACDF for the treatment of three- and four-level disease were compared. Thirty-three patients underwent implantation of zero-profile devices that included titanium screw fixation (Group A). Thirty-five patients underwent implantation of stand-alone PEEK cages without any form of screw fixation (Group B).Results: In Group A, twenty-seven patients underwent a three-level and six patients a four-level ACDF, with a total of 105 levels. In Group B, thirty patients underwent a three-level and five patients underwent a four-level ACDF, with a total number of 110 levels. In Group A, the mean preoperative visual analog scale score (VAS) for arm pain was 6.4 (range 3-8), and the mean postoperative VAS for arm pain decreased to 2.5 (range 1-7). In group B, the mean preoperative VAS of arm pain was 7.1 (range 3-10), and the mean postoperative VAS of arm pain decreased to 2 (range 0-4). In Group A, four patients (12%) developed dysphagia, and in Group B, three patients (9%) developed dysphagia. Conclusions: This study found zero-profile instrumentation and PEEK cages to be both safe and effective for patients who underwent three- and four-level ACDF, comparable to reported series using plate devices. Rates of dysphagia for the cohort were much lower than reports using plate devices. Zero-profile segmental fixation devices and PEEK cages may be considered as viable alternatives over plate fixation for patients requiring multi-level anterior cervical fusion surgery.

Computational design and fabrication of a novel bioresorbable cage for tibial tuberosity advancement application

Tibial tuberosity advancement (TTA) is a promising method for the treatment of cruciate ligament rupture in dogs that usually implies the implantation of a titanium cage as bone implant. This cage is non-biodegradable and fails in providing adequate implant-bone tissue integration. The objective of this work is to propose a new process chain for designing and manufacturing an alternative biodegradable cage that can fulfill specific patient requirements. A three-dimensional finite element model (3D FEM) of the TTA system was first created to evaluate the mechanical environment at cage domain during different stages of the dog walk. The cage microstructure was then optimized using a topology optimization tool, which addresses the accessed local mechanical requirements, and at same time ensures the maximum permeability to allow nutrient and oxygen supply to the implant core. The designed cage was then biofabricated by a 3D powder printing of tricalcium phosphate cement. This work demonstrates that the combination of a 3D FEM with a topology optimization approach enabled the design of a novel cage for TTA application with tailored permeability and mechanical properties, that can be successfully 3D printed in a biodegradable bioceramic material. These results support the potential of the design optimization strategy and fabrication method to the development of customized and bioresorbable implants for bone repair.

Plasma treatment on novel carbon fiber reinforced PEEK cages to enhance bioactivity

Abstract Carbon fiber reinforced polyetheretherketone (CFR-PEEK) has similar mechanical properties to human bone and is considered as the best alternative material to substitute titanium for spine cage implants. To compensate its poor osteogenic properties and limited bioinertness, CFR-PEEK was coated with a thin film of titanium. In the study, we investigated the biological response in vitro of titanium coated CFR-PEEK with different vacuum plasma pretreatments. The so modified surface revealed first hints for a good cell response by excellent cell adhesion and morphology of human osteoblast – like cells MG 63 (ATXX:’CRL-1427). Thus, the findings show that surface roughness of CFR-PEEK material has a profound effect on the biological activity via vacuum plasma treatment.

Single-stage Treatment of Osteomyelitis of the Cervical Spine Using Anterior Instrumentation and Titanium Mesh Cages.

A case series. The aim of this study was to evaluate the clinical outcomes of patients with osteomyelitis of the cervical spine who were treated with single-stage anterior debridement and fusion using titanium mesh cages along with anterior plates. There have been few studies in single-stage surgical treatment of osteomyelitis of the cervical spine using titanium mesh cages along with anterior plates. Twenty-four patients treated for osteomyelitis of the cervical spine are presented. There were 11 male and 13 female with an average age of 53.3 years (42-63). Seventeen patients presented with a neurologic deficit at the time of diagnosis. Surgical treatment consisted of anterior debridement and fusion using titanium mesh cages along with anterior plates as a one-step procedure. The patients' records and radiographs were retrospectively analyzed and follow-up clinical and radiographic data obtained. The median follow-up period was 52 months. There were no implant failures. All patients showed a solid bony fusion without any recurrence of infection at latest follow-up. Changes in pain level, hematologic parameters, and neurologic status demonstrated a significant clinical improvement in all patients. This single-stage surgical treatment for osteomyelitis of the cervical spine provided satisfactory results. There is no increased risk of recurrence or persistence of infection related to the implantation of titanium mesh cages and instrumentation. 4.

Evolution of Design of Interbody Cages for Anterior Lumbar Interbody Fusion.

Anterior lumbar interbody fusion (ALIF) is one of the surgical procedures for the relief of chronic back pain, radiculopathy and neurogenic claudication in patients with degenerative lumbar spine disease that is refractory to conservative therapy, low-grade spondylolisthesis and pseudo arthrosis. Over the past half century, both the surgical techniques and instrumentation required for ALIF have changed significantly. In particular, the designs of ALIF cage and the materials used have evolved dramatically, the common goal being to improve fusion rates and optimize clinical outcomes. The increasing popularity of ALIF is reflected by the increasing abundance of published studies reporting clinical outcomes, surgical techniques and grafting options for ALIF. Developments in cage designs include cylindrical Bagby and Kuslich, cylindrical ray, cylindrical mesh, lumbar-tapered, polyethyl-etherketone cage and integral fixation cages. Biologic implants include bone dowels and femoral ring allografts. Methods for optimization of cage design have included cage dimensions, use of novel composite cage materials and integral fixation technologies. However, the historical development and evolution of cages used for ALIF has not been extensively documented. This article therefore aims to provide an overview of the historical basis for the anterior approach, evolution in design of ALIF cage implants and potential future research directions.

Anterior approach with expandable cage implantation in management of unstable thoracolumbar fractures: Results of a series of 93 patients

IntroductionAnterior approach indications in unstable thoracolumbar fractures (UTLF) are debated. The aim of this study was to evaluate the results of anterior fixation and expandable prosthetic vertebral body cage (EPVBC) implantation alone or combined with a posterior approach in the management of UTLF. Materials and methodsNinety-three patients underwent anterior fixation with implantation of an EPVBC for UTLF from T7 to L5. Long-term kyphosis and vertebral height loss reduction, functional outcomes including visual analogical scale and Oswestry disability index were evaluated. ResultsAnterior fixation led to a significant increase of vertebral body height with a gain of 13% after a previous posterior approach, 38% after a single anterior approach and 65% after combined posterior and anterior approaches (P=0.0001). However, anterior fixation did not significantly enhance the vertebral regional kyphosis angle (P=0.08), except in cases of single anterior approach for thoracic fractures (P=0.03). No significant difference was found between early, 3 months and 1 year postoperative vertebral regional kyphosis angle and vertebral body height (P=0.6). Complete fusion was routinely observed at 1 year postoperatively. rhBMP2 implantation in selected cases appears to be a safe and reliable strategy. No infections or surgical revisions were observed after the anterior approach. ConclusionAnterior approach and EPVBC implantation, in UTLF, is a safe and effective procedure, providing long-term vertebral body height and kyphosis correction. Adverse effects of anterior approach remain acceptable. Single anterior fixation is a reliable surgical alternative in thoracic fractures without posterior spine segment injury or spinal cord compression. These results prompted us to extend anterior approach indications in oncology and infectious diseases.

Development and Implantation of an Individualized 3D Printed Titanium Cage for Cervical Fusion

Introduction At present, all available cervical fusion cages have standardized sizes and mimic the anatomy of the intervertebral disc space more or less. Usually, the patient's anatomy is adapted during the surgery to the cage. Our idea was to respect the individual patient's anatomical situation and manufacture an individual cage with a perfect fitting accuracy. The production of individualized cages might be the next step for further improvement of spinal implants due to their perfect fit and improved load bearing surface. Material and Methods The computer-assisted planning, manufacturing, and implantation of the individualized cervical cage was performed in close co-operation with 3D-Systems Corporation, Rock Hill, SC 29730, USA and EIT Emerging Implant Technologies GmbH, Tuttlingen, Germany. A 3D model of the patient's cervical spine obtained from CT data was rendered. This model is the basis for the exact simulation of the operation. The newly developed 3D planning algorithms and special reconstruction software implemented in a high-end image-processing computer allow a virtual surgical procedure. The correction of degenerative deformities by repositioning of vertebrae and also the virtual resection of osteophytes is possible. The cage implantation can be simulated to check the accuracy of fit. These data are the basis for the production of the cage. This custom-made cage is manufactured of trabecular titanium by selective laser melting (3D printing procedure). Results The pilot project of the first implantation of an individualized cervical cage ever resulted in a high accuracy of fit of the implant. During surgery the cage ‘found’ its correct position after suspending disctraction due to its unique endplate design. Furthermore, it was impossible to move the cage in any direction. Thus, it can be assumed that the individualized cervical implant provides excellent primary fitting accuracy and stability. Conclusion Preconditions for the manufacturing of individualized cervical fusion cages using specific patient data are given. The implantation is uncomplicated. The improved load-bearing surface will lower the rate of implant dislocation and subsidence. The next essential steps will be to improve the workflow of the surgical simulation and shorten the time of the overall production process. The manufacturing of individualized cages at a reasonable price has to be figured out by spine surgeons and the industry.

Validation of Positioning, Lordotic Correction and Lack of Endplate Damage When using a New Expandable Articulated Lumbar Intervertebral Fusion Cage; A Cadaver Study

Introduction Intervertebral lumbar fusion cages became nowadays a useful tool by preserving disc space height, retaining proper tension of ligaments and providing better anterior column support with contained bone graft. Expandable cages, a new available category, help to approach the disc space with less invasive techniques adjusting its height to the local anatomy. There's need in using cages with the widest footprint, able to expand to increase disc height up to normal correcting lordotic alignment, particularly at L4–5 and L5-S1 levels, without damaging the endplates in the process and reducing pre-stress of posterior instrumentation. A 3-dimensional articulated expandable cage was tested in cadavers to verify: its effect on positioning in the disc space, by navigating its two-linked segments in the transversal plane; its expansion without endplate violation and its resultant lordotic correction in the sagittal plane. Material and Methods Five fresh-frozen human cadaver specimens were randomly assigned to two surgeon teams for discectomy and implantation of this new expandable titanium-alloy FLXfit cage through one-sided TLIF approach using fluoroscopy and standard spine instrumentation. No facetectomy or posterior instrumentation were performed. Every cadaver underwent a two level procedure, L2–3 and L5-S1. Each cage allowed a lordotic angled expansion of up to 10° with a dedicated cage tool. After implantation, all specimens were dissected and disc spaces incised for evaluation of positioning and endplate condition as result of expansion. Final positioning was documented with X-rays and lordotic angles were measured. Lordotic increments were calculated by level from pre and post-operatory measurements. Each surgeon rated his experience in designated questionnaires. Results Ten expandable cages of various sizes were implanted according to trial measurements obtained during the procedure. Surgeons successfully inserted, positioned and expanded the cages based on surgical technique. The procedure was reported as being easy to perform by the surgeons. Implant positioning was consistently accomplished in the anterior two-thirds of the disc space near the apophyseal ring due to the articulated feature covering a large footprint. Gradual cage angular expansion was performed till the maximal degree allowed in all cases, customized to each level treated. Analysis of dissected cadavers revealed an effective discectomy with preservation of the annulus except the entry portal. No endplate violation was reported in all specimens. On lateral X-rays, lordotic increment from preoperative values was significantly higher in L2–3 discs, being 7.8°±2.2 (from 5 to 10°). On L5-S1 discs the increase was 4.8°±1.3 (from 4 to 7°). The overall added lordotic correction was on average 12.6°±2.5 per spine. Conclusion The use of 3-dimensional expandable cages in this cadaver study allowed better endplate bone contact with a well-fitted adjustment, according to the level treated without endplate damage. Lordosis correction was achieved differentially depending on the level and original values of alignment. Added up individual correction was shown on overall sagittal correction using two cages, which would be likely enhanced with facet resection and posterior instrumentation. The use of well positioned, large footprint, expandable lordotic correcting cages may lead to a more biomechanically balanced results in lumbar spine fusion.

Report of One Year Follow up of Patients after TLIF using a 3-Dimensional Expandable Cage for Lumbar Fusion with Lordotic Correction

Introduction The use of a new 3 dimensional (3D) expandable cage for TLIF was extensively studied in biomechanical tests, cadaver specimens and preliminary clinical series. A wide footprint is achieved through a one side portal due to the articulated implant positioned in the anterior third of the disc space. The lordotic correction is accomplished due to the expansion of the device in place assisting on the overall sagittal alignment. Previous reports presented showed initial promising clinical results. One year follow up of the first 10 patients is now reported. Material and Methods Ten patients were included in a 12 months prospective review after a TLIF using a 3D Titanium alloy FLXFit expandable cage. The procedure was done for a single or two level fusion with positioning of the cage under fluoroscopy and expansion for disc space height and lordotic correction. All patients were supplemented with posterior instrumentation. Primary clinical outcomes were evaluated by preoperative, 6 months, 12 months and last follow-up visual analog scale (VAS) and the Oswestry Disability Index (ODI) scores. Complications and neurological impairment were recorded. Radiographic assessment of pre and post-operative results was performed with measurement of correction achieved in the frontal and sagittal planes with EOS imaging technology avoiding any distortion on X-Rays. All patients underwent CT scan control at 12 months. Results All ten patients underwent a successful one or two levels instrumented TLIF without any permanent neurological, vascular or visceral complication. The 3D cage implantation provided lordosis augmentation of 8° (± 2.1°) allowing restoration of the sagittal alignment according to pre-op planning. On early post-op CT scans, good footprint and no endplate violation were shown with no cage subsidence. Clinical outcomes showed significant improvement for both VAS and Oswestry scores ( P < 0.05), 3.7 (± 2.9) and 31% (±11) respectively. Similar outcomes were found at 12 months: no cage subsidence, VAS and Oswestry scores ( P < 0.05), 3.5 (± 2.7) and 28,4% (±12) respectively. Conclusion Lumbar interbody fusion using this new 3D expandable cage provided correction of the lordosis in a shorter and effective surgical procedure. A wide footprint well positioned cage, with customized height and angular correction achievement assured an optimal load transmission and biomechanical environment for fusion. Initial clinical results were followed with successful clinical outcomes in all patients.

Minimally Invasive Transforaminal Lumbar Interbody Fusion Using Expandable Technology: A Clinical and Radiographic Analysis of 50 Patients

Interbody cage implantation during minimally invasive surgery for transforaminal lumbar interbody fusion (MIS TLIF) presents challenges. Expandable cages when collapsed facilitate insertion; subsequent expansion in situ optimizes endplate contact. This report describes clinical and radiographic outcomes of MIS TLIF with an expandable cage. Researchers retrospectively analyzed prospective data from 50 patients (62 operative levels) when an expandable interbody spacer was combined with transpedicular posterior stabilization. Clinical outcomes, fusion rates, incidence of reoperation, and device-related complications were obtained from clinical and radiographic records. Mean patient age was 58.1 years (56.2% female). In all, 76% (38/50) underwent 1-level fusion, and 24% (12/50) 2-level fusion. Average operative time was 239.9 ± 86.9 minutes for 1-level and 350.3 ± 74.9 minutes for 2-level procedures; average hospital stay overall was 2.5 ± 1.7 days, with no intraoperative complications reported. Mean visual analogue scale and Oswestry Disability Index scores decreased significantly from preoperative to all postoperative assessment times (6, 12, and 24 months) (P<0.05). Intervertebral disc height (8.3 ± 2.7 vs. 11.3 ± 1.9 mm) increased significantly, with increases sustained over 24 months (P < 0.05). Postoperative radiographs showed no evidence of cage migration, subsidence, or collapse and suggested fusion at all operative levels by 12 months and 24 months (93%, 54/58; 97%, 28/29), respectively. An expandable interbody cage led to significant improvement in clinical and radiographic outcomes after MIS TLIF, including intervertebral disc height restoration and high fusion rates, with no evidence of device-related complications.

Traumatic Periprosthetic Acetabular Fracture Treated with One-Stage Exchange and Bone Reconstruction Using a Synthetic Bone Graft Substitute.

A case of a traumatic periprosthetic acetabular fracture in an elderly patient, which was treated by one-stage hip exchange with implantation of an antiprotrusio cage and reconstruction of the acetabular bone loss with an injectable calcium sulphate/hydroxyapatite bone graft substitute, is reported. The paste-like bone graft substitute was injected through the holes of the antiprotrusio cage. After a setting time of 15 minutes, a low-profile cup was cemented onto the cage using polymethylmethacrylate and a new stem was inserted. The patient was encouraged to ambulate three days postoperatively weight-bearing as tolerated. At the one-year follow-up visit the patient was ambulatory and full weight-bearing without any walking aids. The follow-up radiographs demonstrated stable position and articulation of the revision hip arthroplasty with no signs of loosening of the antiprotrusio cage. However, the most interesting finding was that the bone graft substitute had remodelled to a great extent into bone. This calcium sulphate/hydroxyapatite composite shows high osteoconductive potential and can be used to regenerate bone stock in revision arthroplasty.

Single-stage debridement and spinal fusion using PEEK cages through a posterior approach for eradication of lumbar pyogenic spondylodiscitis: a safe treatment strategy for a detrimental condition.

BackgroundPyogenic infections of the lumbar spine are a rare but critical pathology, yet with considerably high mortality rates. In cases indicating surgical therapy, the implantation of titanium cages or autologous bone grafts represent today's gold standard. Although non-metallic implants such as poly-ether-ether-ketone (PEEK) have proven to be advantageous in diverse degenerative conditions, their saftey and practicability in lumbar spine infection remains questionable. Moreover, the efficacy of a single-step radical debridement of the infected disc space with subsequent fusion from a strictly posterior approach continues to be an issue of debate. We therefore sought to evaluate the feasibility, clinical and radiological outcome of a single-step TLIF procedure using oblique PEEK cages in the surgical management of patients with lumbar pyogenic spondylodiscitis.MethodsFrom January 2009 through December 2013, all patients meeting the indication for surgical treatment of lumbar pyogenic spondylodiscitis were included. Patients demonstrating intact cortical bone on preoperative CT received a single-step radical debridement of the infected intervertebral disc space, posterior screw-and-rod instrumentation and implantation of an oblique PEEK cage using the TLIF technique. Oral antibiotics were continued for 12 weeks postoperatively and clinical and radiological results recorded throughout a minimum 1-year clinical follow-up.ResultsA total of 104 patients were admitted to receive surgical therapy for lumbar pyogenic spondylodiscitis. Within this patient population, 18 patients met the diagnostic criteria to receive the implantation of an oblique PEEK cage. Pathogens were detected in 13 cases with Staph. aureus being the predominant causative organism. All patients were discharged to recover in their domestic environment. Throughout the first year of clinical and radiological follow-up and beyond, none of the 18 patients demonstrated any signs of residual neurologic deficits or recurrent infection. Furthermore, two-plane conventional X-rays showed no significant implant subsidence or failure at any of the given time-points in up to 5 years postoperatively.ConclusionsIn patients meeting the criteria for surgical treatment of lumbar pyogenic spondylodiscitis, the implantation of PEEK cages using a single-step TLIF approach is a safe and feasible procedure. Based on our experience, the concern of a recurrent infection when implanting non-metallic cages may be refuted in carefully selected patients.

Autologous bone graft versus PEKK cage for vertebral replacement after 1- or 2-level anterior median corpectomy.

OBJECT Anterior cervical corpectomy with fusion has become the most widely used procedure for the treatment of multilevel cervical stenosis. Although an autologous bone graft is the gold standard for vertebral replacement after corpectomy, industrial implants have become popular because they result in no donor-site morbidity. In this study, the authors compared clinical and radiological results of autologous iliac grafts versus those of bone-filled polyetherketoneketone (PEKK) cage implants. METHODS The clinical and radiological data of 46 patients with degenerative multilevel cervical stenosis and who underwent 1- or 2-level anterior median corpectomy between 2004 and 2012 were analyzed. The patients in Group 1 were treated with vertebral replacement with an autologous iliac graft, and those in Group 2 were treated with a PEKK cage implant. Each patient also underwent osteosynthesis with an anterior plate-screw system. Visual analog scale (VAS) and European Myelopathy Scale scores, loss of height and regional cervical lordosis angle, and complication rates of the 2 groups were compared. RESULTS The mean follow-up time was 20 months. In both groups, the VAS and European Myelopathy Scale scores improved significantly. The loss of height was 3.7% in patients with iliac grafts and 5.3% in patients with PEKK implants. The rates of osseous fusion were similar in Groups 1 and 2 (94.7% and 91.3%, respectively). At the end of the follow-up period, none of the patients complained about donor-site pain. One patient in Group 1 suffered a fracture of the iliac bone that required osteosynthesis. Four patients in Group 2 had to receive revision surgery for cage and/or plate-screw dislocation and new neurological deficit or intractable pain. CONCLUSIONS Preoperative pain and radicularand myelopathic symptoms improve after decompression irrespective of the material used for vertebral replacement. The use of PEKK cages for vertebral replacement seems to result in a higher risk of implant-related complications. A prospective randomized study is necessary to supply evidence for the use of autografts and artificial implants after anterior cervical corpectomy with fusion.