Cervical Cage Research Articles

Preliminary results of anterior cervical arthroplasty by porous alumina ceramic cage for cervical disc herniation surgery.

Objective:Anterior cervical arthroplasty (ACA) is the gold standard surgery in severe or unresponsive cases of cervical disc herniation, uncarthrosis, and foraminal stenosis. The aim of this study is to establish the impact and outcome evaluations of managing the patients operated for cervical arthroplasty by the intersomatic porous alumina ceramic cervical cages (PACC). The authors describe their experience in the area to allow the comparison of effectiveness of ceramic cages versus other interbody fusion cages.Materials and Methods:Between April 2015 and September 2018, we operated 118 for ACA by using PACC. Among them, 52 were female and 66 were male, with an average age of 46.78 years.Results:The mean symptoms duration was 14.1 months. The most frequent level of the disorder was C5–C6 followed by C6–C7 level. Mean follow-up was 3.3 years. The Neck Disability Index (NDI) and the visual analog scale (VAS) were used to evaluate the patients status. No significant differences were observed between our results and literature data regarding operative time, duration of hospitalization, and NDI; however, we observed a shorter period and higher rate of bony fusion.Conclusion:The results from the present study corroborate that implementing of PACC is a good alternative treatment for the patient operated by ACA for cervical disc herniation or foraminal cervical stenosis.

Evaluation of Different Modalities of Anterior Cervical Discectomy for Treatment of Single and Double Level Cervical Disc Herniation

Introduction: Cervical disc herniation and degenerative disease of the cervical spine are the most common causes of cervical cord and nerve root dysfunction. The surgical treatment of cervical radiculopathy is still controversial. Instead of two possibilities, nowadays three possible treatments concur with each other: anterior cervical discectomy without implantation of any structure, anterior cervical discectomy with fusion, and finally, cervical discectomy with implantation of disc prosthesis. Patients and methods: Twenty patients with cervical disc herniation with radiculopathy, which had not responded to conservative treatment were treated by anterior decompression and cervical disc replacement. All these patients were evaluated preoperatively clinically and radiologically (plain X-rays of cervical spine; A-P, Lateral and dynamic films: flexion, extension and oblique and MRI cervical spine). Nerve conduction study was done to exclude peripheral compression neuropathy and to confirm radiculopathy in selected cases where double entrapment phenomena suspected and followed up for a period of 1 month to 12 months. The technique followed anterior decompression differed according to the way of reconstruction at each level and the patients were accordingly classified into three groups: group A (1-level fusion); where the anterior decompression was accomplished by single level cervical discectomy, and then insertion of cervical cage at this leve, group B (2-level fusion); where the anterior decompression was accomplished by double level cervical discectomy, and then insertion of cervical cage at both levels, group C (hybrid construct); where the anterior decompression was in the form of one level cervical discectomy, followed by cage implantation at this level and another level cervical discectomy followed by insertion of cervical disc prosthesis at the same time. Functional outcome was assessed according to Odom’s criteria. Postoperative plain X-rays of cervical spine (A-P and Lateral) were done at follow-up visits (immediate postoperative, 3 months, 6 months 12 month postoperatively. MRI or CT of the cervical spine is done for patients routinely and for patients not improving or with persistent preoperative complaint or any new neurologic deficit. Results and Discussion: The ages in our patient population ranged from 30 to 50 years, with a mean of 40 ± 5.9 years (mean ± standard deviation). 11/20 patients (55%) were males, and 9/20 (45%) were females. The commonest level affected is C5-C6 level. The most common complaint of patients is neck pain and radiculopathy. Anterior cervical discectomy followed by single level cervical fusion was done on 13 patients, while 5 patients were subjected to anterior cervical discectomy followed by double level cervical fusion and another 2 patients had anterior cervical discectomy followed by cervical artificial disc replacement at one level and zero profile implant insertion and fusion at another level. Regarding the mean duration of hospital stay it was 2.4 days in the single level group while it was 3.8 days in the double level group and 4 days in the hybrid group. Regarding the functional outcome 9 patients (69.2%) had excellent outcome in the single level group versus 3 patients (60%) In the double level group and 2 patients (100%) in the hybrid group, while there were 3 patients (23.1%) who had good outcome in the single level group and 1 patient (20%) in the double level group, finally only one patient in the single level group and 1 patient in the double level group who had satisfactory outcome. There were 2 complications in this study, one (7.7%) in the single level group and one (20%) in the double level group. In the single level group 1 patient had removal of prosthesis due to device failure and hypermobility. In the double level group, one patient had temporary dysphagia and dysphonia. Conclusion: Ideal treatment for cervical degenerative disc disease must deal with and improve its three components (axial neck pain, radiculopathy, and myelopathy), normalize cervical spine biomechanics so not to act as a nidus accelerating the degenerative process, and improves the functional outcome of the patient without serious complications. CDR and ACDF are both effective treatment strategies for managing degenerative conditions of the cervical spine. There is insufficient evidence to show which technique is the most effective and provides the longest-lasting symptom relief.

66 - Effect of Posterior Cervical Cages Supplemental to Anterior Cervical Integrated Cage Fusion on Lordotic Alignment, Foraminal Height, and Intersegmental Space

66 - Effect of Posterior Cervical Cages Supplemental to Anterior Cervical Integrated Cage Fusion on Lordotic Alignment, Foraminal Height, and Intersegmental Space

P16 - Posterior Cervical Cages as a Supplement to the Anterior Integrated Cage and Comparison with Plated ACDF Biomechanical Assessment

P16 - Posterior Cervical Cages as a Supplement to the Anterior Integrated Cage and Comparison with Plated ACDF Biomechanical Assessment

Bioabsorbable self-retaining PLA/nano-sized β-TCP cervical spine interbody fusion cage in goat models: an in vivo study.

Study designThis is an experimental animal study.ObjectiveThe objective of this study was to compare an anterior cervical discectomy and interbody fusion of a novel polylactide/nano-sized β-tricalcium phosphate (PLA/nβ-TCP) bioabsorbable self-retaining cervical fusion cage (BCFC) with an autologous bone graft and polyetheretherketone (PEEK) cages.BackgroundAlthough PLA cervical cages have potential advantages compared with traditional materials, they are not currently routinely used in spine surgery because of undesirable effects such as the lack of osteoconductivity and osteolysis around the implant. This study involved the manufacturing of a bioabsorbable cage from PLA/nβ-TCP that was then used as a device for anterior cervical discectomy and fusion (ACDF) on a goat cervical spine fusion model.Materials and methodsEighteen goats underwent C3/C4 discectomy and were randomly divided into three groups based on the following methods: Group A (n=6), an autologous bone graft; Group B (n=6), PEEK cage filled with an autologous graft; and Group C (n=6), BCFC filled with an autologous iliac bone. Radiography was performed preoperatively and postoperatively and at 1, 4, 8, and 12 weeks after the operation. Disc space height (DSH) was measured at the same time. After 12 weeks, the fused segments were harvested and evaluated with functional radiographic views, biomechanical testing, and histological analyses.ResultsOver a 12-week period, the BCFC and PEEK cage groups exhibited significantly higher DSH values than the bone graft group. Additionally, the BCFC group yielded a significantly lower range of motion in axial rotation than both the autologous bone graft and PEEK cage groups. A histologic evaluation revealed an increased intervertebral bone volume/total volume ratio and better interbody fusion in the BCFC group than in the other groups.ConclusionThe BCFC device exhibited better results than the autologous bone graft and PEEK cages in single-level ACDF models in vivo. This device may be a potential alternative to the current PEEK cages.

Failure Patterns in Standalone Anterior Cervical Discectomy and Fusion Implants.

Anterior cervical discectomy and fusion is commonly performed using an allograft or autograft implant and anterior screw-supported plate. There has been an increase in the use of standalone cage devices due to ease of use and studies suggesting a lower rate of acute postoperative dysphagia. We review our experience with standalone cage devices and identify risk factors, patterns of failure, and revision surgery approaches. We performed a retrospective case series of patients treated at a single tertiary care institution between March 2014 and March 2015. Inclusion criteria were aged 18-100 years, 1- or 2-level anterior cervical discectomy and fusion with a standalone cervical cage. Data collected included demographics, comorbidities, Charlson comorbidity score, primary diagnosis, and surgical characteristics. Descriptive statistics were performed for risk of readmission, implant failure, revision, and other complications. We identified 211 patients who met our study criteria. Average surgical time was 107 ± 43 minutes, with an estimated blood loss of 84.6 ± 32.4 mL. There were 11 (5.2%) readmissions. There were 10 (4.74%) implant failures (5 involving single-level surgery and 5 involving 2-level surgery), with 7 cases of pseudoarthrosis. Mechanisms of failure included a C5 body fracture, fusion in a kyphotic alignment after graft subsidence, and acute spondylolisthesis. Revision surgery after standalone anterior cervical implants can be complex. Posterior cervical fusion remains a valuable approach to avoid possible vertebral body fracture and loss of fusion area associated with the removal of implants secured through the endplates of adjacent vertebral bodies.

Single anterior cervical discectomy and fusion (ACDF) using self- locking stand-alone polyetheretherketone (PEEK) cage: evaluation of pain and health-related quality of life.

Anterior cervical discectomy and fusion (ACDF) constitutes the conventional treatment of cervical disc herniation due to degenerative disc disease (DDD). ACDF with plating presents a variety of complications postoperatively and stand-alone cages are thought to be a promising alternative. The aim of this study was firstly, to analyze prospectively collected data from a sample of patients treated with single ACDF using C-Plus self-locking stand-alone PEEK cage system, without the use of plates or screws, in order to evaluate pain levels of patients, utilizing Neck and Arm Pain scale as an expression of visual analogue scale (VAS). Secondly, we aimed to evaluate health-related quality of life, via the short-form 36 (SF-36) and Neck Disability Index (NDI). Thirty-six patients (19 male and 17 female) with mean age 49.6±7 years old who underwent successful single ACDF using self-locking stand-alone PEEK cage for symptomatic cervical DDD were selected for the study. Neck and Arm pain, as well as SF-36 and NDI were estimated preoperatively and 1, 3, 6, and 12 months postoperatively. Patients underwent preoperative and postoperative clinical, neurological and radiological evaluation. The clinical and radiological outcomes were satisfactory after a minimum 1-year follow-up. All results were statistically important (P<0.05), excluding improvement in NDI measured between 6 and 12 months. SF-36, Neck Pain, as well as Arm Pain featured gradual and constant improvement during follow-up, with best scores presenting at 12 months after surgery, while NDI reached its best at 6 months postoperatively. Generally, all scores showed improvement postoperatively during the different phases of the follow-up. Subsequently, ACDF using C-Plus cervical cage constitutes an effective method for cervical disc herniation treatment, in terms of postoperative improvement on pain levels and health-related quality of life and a safe alternative to the conventional method of treatment for cervical DDD.

Application of biodegradable 3D-printed cage for cervical diseases via anterior cervical discectomy and fusion (ACDF): an in vitro biomechanical study.

To design and fabricate a 3D-printed cervical cage composite of polylactic acid (PLA)/nano-sized and β-tricalcium phosphate (β-TCP). CAD analysis provided a useful platform to design the preliminary cage. In vitro cell culture and in vivo animal results showed promising results in the biocompatibility of the constructs. Endplate matching evaluation showed better matching degree of 3D-printed cages than those of conventional cages. Biomechanical evaluation showed better mechanical properties of 3D-printed cages than those of conventional cages. The novel 3D printed PLA/pβ-TCP cage showed good application potential, indicating a novel, feasible, and inexpensive method to manufacture cervical fusion cages.

A new zero-profile, stand-alone Fidji cervical cage for the treatment of the single and multilevel cervical degenerative disc disease

To investigate the clinical and radiological results of the new zero-profile, stand-alone Fidji cervical cage to treat single- and multiple-level cervical DDD, and evaluate the safety and efficiency. Between October 2011 and July 2014, 72 consecutive patients (41 males and 31 females; mean age 50.9years [range, 33–68years]) with cervical DDD who underwent surgery and were followed for more than 2years were enrolled in this study (mean 31.1months, range 24–47months). The study compared clinical outcomes, radiologic parameters and complication rates. The SF-36, VAS, NDI, and JOA scores of all patients were improved significantly after surgery at any time point. (all p<0.05). The C2–C7 Cobb angle and the disc height index (DHI) of all patients were improved significantly after surgery at any time point (all p<0.05). From 3months after surgery to final follow-up the DHI showed a significant reduction comparing 1week after surgery (all p<0.05). The fusion rates were 91.7% (66/72) and the radiologic mean fusion time was 9.9months. Radiological evidence of adjacent segment degeneration (ASD) was observed in 4/41 patients (9.8%). Postoperative complications included epidural hematoma, hoarseness, dysphagia, axial neck pain, and subsidence. The zero-profile, stand-alone Fidji cervical cage for ACDF can be considered an effective, reliable and safe alternative procedure in the treatment of cervical DDD.

Comparison of polyetheretherketone (PEEK) cage and cervical disc prostheses used in anterior cervical microscopic discectomy operations

Objective: The aim of this study was to radiologically and clinically compare the polyetheretherketone (PEEK) cage and cervical disc prostheses used in anterior cervical microdiscectomy operations during the postoperative period. Methods: The study evaluated 25 cervical disc hernia patients. The cervical disc prosthesis group (Group A) comprised 10 patients while the PEEK cage group (Group B) comprised 15 patients. Before and after the operation, the cervical graphics from radiological monitoring and VAS, NDI and Odom scores from clinical monitoring were used. The patients’ preoperative and postoperative cervical graphics disc height, cervical axis and segmental angles were evaluated to determine statistical relationships with neurological situation and quality of life. Results: In the cervical disc prosthesis group (Group A) in the early postoperative period (3rd week), 3rd month and late period (18-36 months), the intervertebral disc height measurements were significantly higher than the cervical PEEK cage group (Group B) (early p

Perioperative complications in patients treated with posterior cervical fusion and bilateral cages.

Context:Posterior cervical cages have recently become available as an alternative to lateral mass fixation in patients undergoing cervical spine surgery.Aims:The purpose of this study was to quantify the perioperative complications associated with cervical decompression and fusion in patients treated with a posterior cervical fusion (PCF) and bilateral cages.Settings and Design:A retrospective, multicenter review of prospectively collected data was performed at 11 US centers.Subjects and Methods:The charts of 89 consecutive patients with cervical radiculopathy treated surgically at one level with PCF and cages were reviewed. Three cohorts of patients were included standalone primary PCF with cages, circumferential surgery, and patients with postanterior cervical discectomy and fusion pseudarthrosis. Follow-up evaluation included clinical status and pain scale (visual analog scale).Statistical Analysis Used:The Wilcoxon test was used to test the differences for the data. The P level of 0.05 was considered significant.Results:The mean follow-up interval was 7 months (range: 62 weeks - 2 years). The overall postsurgery complication rate was 4.3%. There were two patients with neurological complications (C5 palsy, spinal cord irritation). Two patients had postoperative complications after discharge including one with atrial fibrillation and one with a parietal stroke. After accounting for relatedness to the PCF, the overall complication rate was 3.4%. The average (median) hospital stay for all three groups was 29 h.Conclusions:The results of our study show that PCF with cages can be considered a safe alternative for patients undergoing cervical spine surgery. The procedure has a favorable overall complication profile, short length of stay, and negligible blood loss.

Research Regarding the Manufacturing through AM Technologies of an Implant for Cervical Disc Replacement

Worldwide, accidents are one of the main causes of illness in developed and undeveloped socio-economic countries. Additive Manufacturing (AM) technologies bring extremely useful and advantageous applications for the new neurosurgical procedures. Because the surgical insertion of devices for cervical disc replacement is very difficult, the development of new devices that can minimize these disadvantages, are needed. The aim of this paper was to improve the characteristics of an implant for cervical intervertebral disc replacement, a model based on an existing implant. A cervical cage designed for stabilization and arthrodesis between the cervical vertebrae was analyzed. A new design of a cage that have some improvements, useful for patient safety, as well as for facilitating the surgery was developed. The new proposed design was verified through Fine Element Analysis.

Multilevel cervical laminectomy and fusion with posterior cervical cages.

Context:Cervical spondylotic myelopathy (CSM) is a progressive disease that can result in significant disability. Single-level stenosis can be effectively decompressed through either anterior or posterior techniques. However, multilevel pathology can be challenging, especially in the presence of significant spinal stenosis. Three-level anterior decompression and fusion are associated with higher nonunion rates and prolonged dysphagia. Posterior multilevel laminectomies with foraminotomies jeopardize the bone stock required for stable fixation with lateral mass screws (LMSs).Aims:This is the first case series of multilevel laminectomy and fusion for CSM instrumented with posterior cervical cages.Settings and Design:Three patients presented with a history of worsening neck pain, numbness in bilateral upper extremities and gait disturbance, and examination findings consistent with myeloradiculopathy. Cervical magnetic resonance imaging demonstrated multilevel spondylosis resulting in moderate to severe bilateral foraminal stenosis at three cervical levels.Materials and Methods:The patients underwent a multilevel posterior cervical laminectomy and instrumented fusion with intervertebral cages placed between bilateral facet joints over three levels. Oswestry disability index and visual analog scores were collected preoperatively and at each follow-up. Pre- and post-operative images were analyzed for changes in cervical alignment and presence of arthrodesis.Results:Postoperatively, all patients showed marked improvement in neurological symptoms and neck pain. They had full resolution of radicular symptoms by 6 weeks postoperatively. At 12-month follow-up, they demonstrated solid arthrodesis on X-rays and computed tomography scan.Conclusions:Posterior cervical cages may be an alternative option to LMSs in multilevel cervical laminectomy and fusion for cervical spondylotic myeloradiculopathy.

Minimally invasive cervical spine surgery.

Degenerative disorders of the cervical spine requiring surgical intervention have become increasingly more common over the past decade. Traditionally, open surgical approaches have been the mainstay of surgical treatment. More commonly, minimally invasive techniques are being developed with the intent to decrease surgical morbidity and iatrogenic spinal instability. This study will review four minimally invasive cervical techniques that have been increasingly utilized in the treatment of degenerative cervical spine disease. A series of PubMed-National Library of Medicine searches were performed. Only articles in English journals or with published with English language translations were included. Level of evidence of the selected articles was assessed. The significant incidence of postoperative dysphagia following ACDF has led to the development and increased use of zero-profile, stand-alone anterior cervical cages. The currently available literature examining the safety and effectiveness of zero-profile interbody devices supports the use of these devices in patients undergoing single-level ACDF. A multitude of studies demonstrating the significant incidence and impact of axial neck pain following open posterior spine surgery have led to a wave of research and development of techniques aimed at minimizing posterior cervical paraspinal disruption while achieving appropriate neurological decompression and/or spinal fixation. The currently available literature supports the use of minimally invasive posterior cervical laminoforaminotomy for the treatment of single-level radiculopathy. The literature suggests that fluoroscopically-assisted percutaneous cervical lateral mass screw fixation appears to be a technically feasible, safe and minimally invasive technique. Based on the currently available literature it appears that the DTRAX® expandable cage system is an effective minimally invasive posterior cervical technique for the treatment of single-level cervical radiculopathy. Minimally invasive posterior cervical techniques continue to expand with the improvement of surgical instrumentation, microsurgical techniques and improved understanding of spinal biomechanics. While several MIS approaches already exist, there is a need for advanced and improved techniques for use in posterior cervical surgery.

Use of a Zero-Profile Device for Contiguous 2-Level Anterior Cervical Diskectomy and Fusion: Comparison with Cage with Plate Construct

A new zero-profile, standalone device (Zero P) was recently developed and has shown a lower incidence rate of complications and competitive clinical outcomes compared with anterior cervical cage with plate construct (CP) in single and multilevel anterior cervical diskectomy and fusion (ACDF). However, there is still concern whether Zero P is appropriate for multilevel ACDF. In addition, there have been few reports of contiguous 2-level ACDF used in conjunction with Zero P. We reviewed contiguous 2-level ACDF performed from December 2006 to February 2015. A total of 63 patients met inclusion criteria for the study (CP group= 32 cases; Zero P group= 31 cases). All preoperative and postoperative clinical and radiologic parameters were recorded. These parameters were compared between both groups. The postoperative change of Cobb S over time in the Zero P group was significantly different from that in the CP group. The maintenance of Cobb S in the Zero Pgroup was better than that in the CP group (P < 0.05). The maintenance of anterior intervertebral disk height (IDH) at postoperative assessment for the Zero P group was significantly better than that in the CP group (P < 0.05). Within-group comparison of the postoperative change of anterior and posterior IDH over time revealed that the anterior IDH was significantly lower than the posterior IDH in the Zero P group (P < 0.05). For 2-level contiguous ACDF, the use of a zero-profile device has the capacity to show compatible outcomes in correction and maintenance of segmental angle if the anterior titanium alloy plate is properly positioned at the anterior vertebral line.

A comparison of a new zero-profile, stand-alone Fidji cervical cage and anterior cervical plate for single and multilevel ACDF: a minimum 2-year follow-up study.

To compare perioperative parameters, clinical outcomes, radiographic parameters, and complication rates of the new zero-profile, stand-alone Fidji cervical cage with those of the stand-alone cages with a titanium plate for anterior cervical discectomy and fusion (ACDF) for the surgical treatment of single- and multilevel cervical degenerative disc disease (DDD). Between October 2009 and December 2013, 152 consecutive patients [86 males and 52 females; mean age 51.0years (range 30-69years)] with cervical DDD, who underwent surgery and were followed for more than 2years, were enrolled in this study and divided into the cage group and plate group. The study compared perioperative parameters, surgery-related and implant-related complication rates, clinical outcomes, and radiologic parameters. The clinical and radiologic results in both groups were satisfactory after a minimum 2-year follow-up. No significant differences between the cage group and plate group in terms of improvement in the 36-Item Short Form Health Survey, visual analogue scale, Neck Disability Index, Japanese Orthopedic Association scores, disc height, mean fusion time, fusion rate, adjacent segment degeneration, and restoration of cervical lordosis, but the cage group was associated with a lower risk of postoperative dysphagia, shorter operation time, less blood loss, less cost of index surgery, and relatively greater simplicity than the plate group. The zero-profile, stand-alone Fidji cervical cage for ACDF is an effective, reliable, and safe alternate to the conventional method for the treatment of cervical DDD. However, there is no definitive evidence that Fidji cervical cage has better intermediate-term outcomes than the stand-alone cages with a titanium plate for ACDF.

Bilateral posterior cervical cages provide biomechanical stability: assessment of stand-alone and supplemental fixation for anterior cervical discectomy and fusion.

IntroductionSupplemental posterior instrumentation has been widely used to enhance stability and improve fusion rates in higher risk patients undergoing anterior cervical discectomy and fusion (ACDF). These typically involve posterior lateral mass or pedicle screw fixation with significant inherent risks and morbidities. More recently, cervical cages placed bilaterally between the facet joints (posterior cervical cages) have been used as a less disruptive alternative for posterior fixation. The purpose of this study was to compare the stability achieved by both posterior cages and ACDF at a single motion segment and determine the stability achieved with posterior cervical cages used as an adjunct to single- and multilevel ACDF.MethodsSeven cadaveric cervical spine (C2–T1) specimens were tested in the following sequence: intact, C5–C6 bilateral posterior cages, C6–C7 plated ACDF with and without posterior cages, and C3–C5 plated ACDF with and without posterior cages. Range of motion in flexion–extension, lateral bending, and axial rotation was measured for each condition under moment loading up to ±1.5 Nm.ResultsAll fusion constructs significantly reduced the range of motion compared to intact in flexion–extension, lateral bending, and axial rotation (P<0.05). Similar stability was achieved with bilateral posterior cages and plated ACDF at a single level. Posterior cages, when placed as an adjunct to ACDF, further reduced range of motion in both single- and multilevel constructs (P<0.05).ConclusionThe biomechanical effectiveness of bilateral posterior cages in limiting cervical segmental motion is comparable to single-level plated ACDF. Furthermore, supplementation of single- and multilevel ACDF with posterior cervical cages provided a significant increase in stability and therefore may be a potential, minimally disruptive option for supplemental fixation for improving ACDF fusion rates.

Clinical and Radiographic Results of Indirect Decompression and Posterior Cervical Fusion for Single-Level Cervical Radiculopathy Using an Expandable Implant with 2-Year Follow-Up.

Background Indirect posterior cervical nerve root decompression and fusion performed by placing bilateral posterior cervical cages in the facet joints from a posterior approach has been proposed as an option to treat select patients with cervical radiculopathy. The purpose of this study was to report 2-year clinical and radiologic results of this treatment method. Methods Patients who failed nonsurgical management for single-level cervical radiculopathy were recruited. Surgical treatment involved a posterior approach with decortication of the lateral mass and facet joint at the treated level followed by placement of the DTRAX Expandable Cage (Providence Medical Technology, Lafayette, California, United States) into both facet joints. Iliac crest bone autograft was mixed with demineralized bone matrix and used in all cases. The Neck Disability Index (NDI), visual analog scale (VAS) for neck and arm pain, and SF-12 v.2 questionnaire were evaluated preoperatively and 2 years postoperatively. Segmental (treated level) and overall C2-C7 cervical lordosis, disk height, adjacent segment degeneration, and fusion were assessed on computed tomography scans and radiographs acquired preoperatively and 2 years postoperatively. Results Overall, 53 of 60 enrolled patients were available at 2-year follow-up. There were 35 females and 18 males with a mean age of 53 years (range: 40-75 years). The operated level was C3-C4 (N = 3), C4-C5 (N = 6), C5-C6 (N = 36), and C6-C7 (N = 8). The mean preoperative and 2-year scores were NDI: 32.3 versus 9.1 (p < 0.0001); VAS Neck Pain: 7.4 versus 2.6 (p < 0.0001); VAS Arm Pain: 7.4 versus 2.6 (p < 0.0001); SF-12 Physical Component Summary: 34.6 versus 43.6 (p < 0.0001), and SF-12 Mental Component Summary: 40.8 versus 51.4 (p < 0.0001). No significant changes in overall or segmental lordosis were noted after surgery. Radiographic fusion rate was 98.1%. There was no device failure, implant lucency, or surgical reinterventions. Conclusions Indirect decompression and posterior cervical fusion using an expandable intervertebral cage may be an effective tissue-sparing option in select patients with single-level cervical radiculopathy.

The Stand-Alone Cervical Cages with Integrated Screw Fixation: Results in 315 Consecutive Operated Levels

Introduction Background: Cervical disc disease at C2/3, C3/4 and C7/T1 is less common. Fusion with cages &amp; plating is the standard treatment at these levels and in multi-level disc disease. This is not without significant risks related to the need of larger exposure and anterior muscular dissection. Stand-alone cages with integrated screw fixation obviate the need for plating and larger exposure. Material and Methods To assess the exposure / cage related morbidities and fusion rates in Stand-Alone cervical cages with Integrated Screw Fixation. Design: Retrospective chart review. Subjects: 315 levels were operated in 253 patients from February 2009 to February 2015. Single and Multilevel cages were performed in 201 and 52 patients respectively. 201 of the 253 patients underwent single level discectomy with Stand-Alone cervical cages with Integrated Screw Fixation at C3/4 and C7/T1 levels. 52 patients underwent 114 multi-level discectomies with Stand-Alone cervical cages with Integrated Screw Fixation Results Operative time was shorter. There was no reported permanent exposure/ cage related morbidities in all operated levels. 3 patients with traumatic disc disruption required further surgery for lateral mass fixation. 12 patients had mild dysphagia that resolved during follow up with no patient having complains of dysphagia at 3- months follow up. Fusion rates were 95% at single level and 90% at multi-level discectomies at the last follow up. No patient required cage related surgical revision. Conclusion The current results support the use of Stand-Alone cervical cages with Integrated Screw Fixation especially at difficult levels at C3/4 and C7/T1 and in multi-level discectomies as it obviate the need for plating and larger exposure with less reported dysphagia and implant related complications.

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.