Anterior Plate Construct Research Articles

Comparative analysis of risk factors associated with degeneration of adjacent segments: zero-profile anchored spacer vs. anterior cervical plate and cage construct.

Anterior cervical discectomy and fusion (ACDF) is an established treatment for cervical degenerative disc disease, but cervical spine surgery may affect sagittal alignment parameters and induce adjacent segment degeneration (ASD). This study aimed to determine the risk factors for developing ASD following anterior cervical plate and cage (ACPC) compared with the use of zero-profile anchored spacer (ROI-C). A retrospective contrastive study included 105 patients who underwent ACPC or ROI-C between January 2014 and October 2019 at our treatment centre. There were 50 cases in the ROI-C group and 55 patients in the ACPC group. Clinical and radiological results and the incidence of ASD were assessed after surgery. All patients were further divided into the ASD and non-ASD groups for subgroup analysis. At each follow-up time, there was no statistically significant in radiographic parameters between the two groups. The overall ASD rate was higher in the ACPC group than in the ROI-C group (65.5% vs. 44.0%, p = 0.027). The low preoperative Cobb angle, low preoperative segment angle (SA), and loss of Cobb (ΔCobb) were significantly correlated with ASD. However, clinical outcomes were not associated with ASD at any postoperative follow-up visit. Equally good therapeutic effects were achieved with both the ROI-C and ACPC. The occurrence of ASD was considerably higher in the ACPC group than in the ROI-C group. The preoperative Cobb angle, preoperative SA, and ΔCobb were the most associated with an increase in the risk of ASD.

Stand-Alone Anchored Spacer vs Anterior Plate Construct in the Management of Adjacent Segment Disease after Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis of Comparative Studies.

Systematic Review and Meta-Analysis. This study aimed to evaluate the clinical and radiological outcomes of surgically treated adjacent segment disease (ASDis) following ACDF with either anterior plate construct (APC) or stand-alone anchored spacers (SAAS). Multiple databases were searched until December 2022 for pertinent studies. The primary outcome was health-related quality of life outcomes [JOA, NDI, and VAS], whereas, the secondary outcomes included operative characteristics [estimated blood loss (EBL) and operative time (OT)], radiological outcomes [C2-C7 Cobb angle, disc height index (DHI) changes, fusion rate], and complications. A total of 5 studies were included, comprising 210 patients who had been surgically treated for cervical ASDis. Among them, 113 received APC, and 97 received SAAS. Postoperative dysphagia was significantly higher in the APC group [47% vs 11%, OR = 7.7, 95% CI = 3.1-18.9, P < .05]. Similarly, operative time and blood loss were higher in the APC group compared to the SAAS group; [MD = 16.96, 95% CI = 7.87-26.06, P < .05] and [MD = 5.22, 95% CI = .35 - 10.09, P < .05], respectively. However, there was no difference in the rate of prolonged dysphagia and clinical outcomes in terms of JOA, NDI, and VAS. Furthermore, there was no difference in the radiological parameters including the C2-7 Cobb angle and DHI as well as the fusion rate. Our meta-analysis demonstrated that both surgical techniques (APC and SAAS) are effective in treating ASDis. However, with low certainty of the evidence, considering patients are at high risk of dysphagia following revision cervical spine surgery SAAS may be the preferred choice.

Stand-alone anterior cervical decompression and fusion surgery: A cohort study evaluating a shaped cage without plates or screws.

BackgroundThe anterior approach to the cervical spine is the most commonly used surgery with effective decompression and less surgical trauma. Anterior plate construct (APC) is considered a standard technique. However, it appears to cause implant failure and postoperative dysphagia. Due to these reasons, locking stand-alone cages (LSCs) without the addition of an anterior plate have been developed and gained popularity in the past decade. In theory, an LSC could provide immediate load-bearing support to the anterior column of the cervical spine and may enhance the rate of arthrodesis. However, screw skiving and backing off are known complications of LSC. Given the characteristic shape of cervical discs, we wondered whether there may be a role for a shape-conforming cage without screws and plates to achieve desired outcomes, i.e., a true stand-alone cage (TSC). A single surgeon cohort using the cage in a heterogenic set of indications was evaluated.MethodsA total of 45 patients with degenerative cervical conditions who underwent surgery using TSC using CoRoent Small Contoured peek cage (Nuvasive, San Diego, CA) and Orthoblend™ (Medtronics, Memphis, TN) were retrospectively reviewed. Comparisons between preoperative and postoperative Numeric Rating Scale (NRS), the modified AAOS-Modems disability outcome, Neck Disability Index (NDI) scores, and Short Form 36 were evaluated. Operative time, the occurrence rate of fusion, lordosis change of cervical spine, and occurrence rate of complications were evaluated.ResultsThere were one-level (n = 15), two-level (n = 24), and three-level (n = 6) cases making a total of 81 cages implanted and studied. The mean operative time was 132.7 min. The group demonstrated significant improvements in NRS, AAOS-Modems disability outcome, and NDI scores after surgery (mean follow-up 12 months). The cervical lordosis at pre- and last follow-up period was 8.7 ± 2.2° and 8.3 ± 3.2°, respectively. The complication rate was 21.2%.ConclusionsTSC yielded satisfactory long-term clinical and radiological outcomes; this preliminary report can form the basis of a cost–benefit analysis study either prospectively or by way of meta-modeling comparing APC, LSC to TSC.

Functional Outcomes of Patella Fractures Treated With Anterior Plate Osteosynthesis at One Year.

To evaluate the functional outcomes of patients with displaced patellar fractures treated with anterior plate constructs. Prospective cohort and retrospective clinical and radiographic assessment. Level I Trauma Center. Between 2014 and 2018, 18 patients who underwent operative intervention for an isolated, displaced patella fracture (OTA/AO 34C1-3) with a minimum of 1-year follow-up agreed to participate in the study. The mean follow-up was 19.5 ± 6.0 months. Patients were treated with 2.4 or 2.7-mm plates and supplemental screws or cerclage wires. Patients were evaluated with the Short Form-36 Survey and the Knee Injury and Osteoarthritis Outcome Scores and asked about symptomatic implants. The range of motion was assessed by goniometer. The cohort had no wound complications, infections, nonunion, loss of reduction, or implant failure. Active knee flexion was 131 ± 7 degrees. Five patients (28%) endorsed implant irritation. Only one patient (5.5%) underwent implant removal, which consisted of transverse screw removal alone. Twelve of the 14 patients (86%), who were previously employed, returned to work at 10 ± 7 weeks. All Knee Injury and Osteoarthritis Outcome Scores subscale scores and the Short Form-36 Survey scores for physical functioning, limitations due to physical health, limitations due to mental health, and social functioning were significantly lower than reference population norms (P < 0.05). Anterior plating provides reliable fixation for displaced patellar fractures and results in a low incidence of implant irritation. However, patients who had anterior fixation for displaced patella fractures continue to exhibit functional deficits at 1-year postoperatively. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Impact Plate Application on the Sagittal Plane Correction after Anterior Cervical Discectomy and Fusion Compared to Stand Alone Cage.

Background Data: Anterior cervical discectomy and fusion (ACDF) is the treatment of choice for cervical degenerative disc disease, which causes neurological symptoms such as radiculopathy and/or myelopathy. Anterior cervical discectomy and fusion with stand-alone cage (ACDF-CA) is a successful option to treat cervical disc disease, but long-term follow-up showed complications like cage subsidence and pseudoarthrosis. Then, anterior cervical decompression and fusion with cage and plate (ACDF-CP) was developed to decrease complications of the stand-alone cage; however, it showed complications like dysphagia. Study Design: This is a retrospective clinical case series. Purpose: To compare the role of anterior plate constructs (ACDF-CP) and stand-alone cage (ACDF-CA) in maintaining sagittal plane correction. Patients and Methods: We retrospectively reviewed the lateral cervical radiographs of all patients who underwent ACDF-CA or ACDF-CP between 2011 and 2015. Radiological findings (cervical lordosis, segmental lordosis, cage subsidence, and disc height) were compared (preoperatively, immediately, and 6 and and 12 months postoperatively). Results: Sixty-five patients underwent ACDF, including 88 operative disc levels, 29 (44.6%) ACDF-CA, and 36 (55.6%) ACDF-CP. There were 41 (63.1%) males and 24 (36.9%) females, with a mean age of 47.7 ± 9.32 years. Forty percent of the procedures were conducted by orthopedic spine surgeons and 60% by neurosurgeons. The most common operated level was C5-C6 followed by C6-C7. Initially, ACDF-CA showed better surgical correction than ACDF-CP in terms of cervical lordosis and segmental lordosis but did not reach the statistically significant value (p = 0.692, CI: [-4.8]-7.28), whereas ACDF-CP maintains these corrections more than ACDF-CA at final follow-up despite being statistically insignificant (p = 0.506, CI: [-7.05]-3.54). No difference was detected in disc height and cage subsides between the two groups. Conclusion: The data in this study may suggest that the ACDF-CA construct was slightly better than ACDF-CP in the surgical correction of the cervical curve, whereas ACDF-CP maintained the correction at final follow-up despite the insignificant statistical value. (2020ESJ216)

Locking stand-alone cage versus anterior plate construct in anterior cervical discectomy and fusion: a systematic review and meta-analysis based on randomized controlled trials.

To evaluate the efficacy of locking stand-alone cage (LSC) compared with anterior plate construct (APC) in anterior cervical discectomy and fusion (ACDF). A comprehensive literature search was carried out in PubMed, Embase, Web of Science, and Cochrane Library to screen randomized controlled trials (RCTs) that directly compared LSC with APC in ACDF. The Cochrane Collaboration's tool was used for assessment of study quality. Data were analyzed with the Review Manager 5.3 software. A total of seven RCTs were included. The results revealed no significant differences between LSC and APC in ACDF regarding the fusion rate, Japanese Orthopaedic Association score, visual analogue scale score, neck disability index score, hospital stay, subsidence rate, cervical lordosis, segmental Cobb angle, and disc height. However, LSC was associated with a significantly shorter operation time, less blood loss, lower overall incidence of dysphagia, and lower adjacent-level ossification (ALO) rate compared with APC. In summary, LSC is not only a safe and effective device for ACDF but also has the advantages of significantly reduced operation time, blood loss, overall incidence of dysphagia, and ALO rate over APC. Therefore, LSC is a better alternative than APC for the patients undergoing ACDF procedures.

Radiographic Fusion Rates Following a Stand-alone Interbody Cage Versus an Anterior Plate Construct for Adjacent Segment Disease After Anterior Cervical Discectomy and Fusion

Case-control. The aim of this study was to evaluate fusion rates and compare a stand-alone cage construct with an anterior-plate construct in the setting revision anterior cervical discectomy and fusion (ACDF) for adjacent segment disease. Anterior cervical discectomy and fusion are considered the criterion standard of surgical treatment for cervical myelopathy and radiculopathy. One common consequence is adjacent segment disease. Treatment of adjacent segment disease is complicated by the previous surgical implants, which may make application of an additional anterior cervical plate difficult. Stand-alone cage constructs obviate the need for removal or revision of prior implants in the setting of adjacent segment disease. All patients undergoing surgery for adjacent segment disease in a 2-year period were identified and separated into groups based on implant construct. A control group of patients undergoing primary, single-level ACDF were selected from during the same 2-year period. Demographic variables, fusion rate, and reoperation rate were compared between groups. Continuous variables were compared using Student t test, fusion, and revision rates were compared using Pearson χ test. Patients undergoing primary ACDF had lower age and American Society of Anesthesia score as well as shorter operative time. Fusion rate was higher for primary ACDF compared to all patients who underwent ACDF for adjacent segment disease (95% vs. 74%). When compared to primary ACDF, patients with a stand-alone cage construct had significantly lower fusion rate (69% vs. 95%) and higher reoperation rate (14% vs. 0%). There were no significant differences in anterior plate construct versus stand-alone cage construct in terms of fusion and reoperation. Symptomatic adjacent segment disease can be managed surgically with either revision anterior plating or a stand-alone cage constructs, although our results raise questions regarding a difference in fusion rates that requires further investigation. 3.

Cervical Spine Fusion: Biomechanics of a Three-Level Cadaver Model Comparing Anterior Plate versus Stand-Alone Cage.

Study Design-Biomechanical cadaveric study. Objective-Long anterior cervical plate and cage (APC) constructs have a risk of pseudarthrosis with minor bone resorption. Stand-alone cages (SACs) allow settling. The biomechanics of SAC have been investigated, but not multilevel, compression screw SAC. The purpose of this study is to evaluate the biomechanical safety of three-level SAC versus APC. Methods-Discectomies at three levels of five human cadaver spines (T1-C3) were fixed with SAC. A 0.18 mm thick shim was interposed between the cage and the superior endplate, and a pressure transducer map was placed between the cage and the inferior endplate. Tests were performed in flexion-extension and then repeated after removing the shims to simulate minor bone resorption. Subsequently, APC was applied and experiments were repeated. The pressure between each cage and endplate and motion of the implants were measured. Results-The range of motion (ROM) of SAC and APC constructs were comparable. The contact area and pressure between cage and endplate did not significantly change during motion with SAC. Shim removal did not significantly affect ROM, contact area, or average pressure measures. For APC, both contact area and pressure decreased from extension to flexion. Shim removal caused a significant loss of contact area and pressure. Conclusions-SAC provided comparable rigidity to the conventional APC construct while maintaining compression at the endplate-cage interface throughout flexion-extension and after minor bone resorption.

Peritalar Motion after Simulated Ankle Fusion in a Cadaveric Model

Category:Ankle Arthritis, Basic Sciences/BiologicsIntroduction/Purpose:Adjacent joint disease often occurs after many orthopaedic surgical interventions. Specifically in the foot and ankle, subtalar arthritis has been demonstrated as a long term sequelae after ankle arthrodesis. The purpose of this study was to evaluate real time qualitative and quantitative motion differences in the hindfoot and midfoot during simulated gait, both before and after ankle fusion in a cadaveric model. Data recorded from each cadaveric trial is used in conjunction with a CT scan of each specimen, allowing creation of a three-dimensional, real time, anatomic model of motion of the foot and ankle.Methods:Three human cadaveric specimens (lower leg and foot) were obtained and prepared for testing. Taking care to preserve the ligamentous and tendinous attachments, radiopaque fiducial makers were placed in each bone (tibia, fibula, talus, calcaneus, navicular, all cuneiforms, 1st metatarsal). CT scan of each specimen was then performed, and used to develop a three dimensional anatomic model of the specimen. Each specimen was then mounted into a custom built apparatus, and load was applied to the construct using a follower load model. Each specimen was taken through two full cycles of the simulated stance phase. Kinematic data of the individual bones/joints were measured in real time, using optoelectronic targets, and saved for later comparison. Next, tibiotalar fusion was performed on each of the previously tested specimens using an anterior plate and screw construct. The specimens were again cycled in the same fashion and data was recorded in the same manner.Results:Tibiotalar fusion successfully eliminated motion between the talus and tibia, directly altering the normal kinematics of the foot ankle complex. Quantitatively, the motion at the subtalar and talonavicular joints increased only slightly with fusion. However, this represents a relative increased motion demand at each joint that exceeds what was observed in the non-fusion condition.Qualitatively, the motion curves for the talocalcaneal and talonavicular joints were altered when compared to the non-fusion state (Figure 1). The qualitative change in motion revealed a relative linkage of motion between the subtalar and talonavicular joints and this was consistently observed across all specimens.Conclusion:Simulated ankle fusion via an anterior plate and screw construct directly alters the kinematics of the downstream (talocalcaneal and talonavicular) joints. Real time observation demonstrates a relative linkage of the motion occurring in the subtalar and talonavicular joints. This linkage resulted in alteration from the observed physiologic motion that occurred in these joints during the non-fusion condition. These findings may provide insight into the etiology of adjacent segment disease seen in the subtalar and talonavicular joints after ankle fusion.

Clinical outcomes of locking stand-alone cage versus anterior plate construct in two-level anterior cervical discectomy and fusion: a systematic review and meta-analysis

Two-level cervical degenerative disc disease (cDDD) can be effectively treated by anterior cervical discectomy and fusion (ACDF) similarly to single-level cDDD. Traditionally an anterior plate construct (APC) approach has been utilized, but ACDF without plate with a locking stand-alone cage (LSC) approach has emerged as an alternative option. The aim of this study was to compare the clinical outcome of LSC and APC in contiguous two-level ACDF used to treat cDDD the current literature. Searches of seven electronic databases from inception to March 2018 were conducted following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Extracted data were analysed using meta-analysis of proportions. The nine observational studies that satisfied all criteria described a pooled cohort of 687 contiguous two-level cDDD cases managed by ACDF, with 302 (44%) and 385 (56%) managed by LSC and APC approaches, respectively. When compared with APC, LSC was associated with significantly increased subsidence likelihood (OR 2.75; p < 0.001), greater disc height (MD 0.60mm; p = 0.04) and reduced cervical lordosis (MD - 2.52°; p = 0.04) at last follow-up. Operative outcomes, fusion rates, functional scores and postoperative dysphagia rates were comparable. Although significant radiological differences were most evident, the comparability between LSC and APC in contiguous two-level ACDF with respect to all other clinical outcomes does not implicate one approach as clearly superior to the other in two-level ACDF. Larger, randomized studies with longer follow-up are required to delineate outcomes further to validate the findings of this study. These slides can be retrieved under Electronic Supplementary Material.

Early Outcomes on the Use of an Anterior Plate for complicated Ankle Fusions

Category: Ankle Introduction/Purpose: An ankle fusion is indicated for severe osteoarthritis of the ankle. An anterior ankle fusion plate for tibiotalar fusions provides a rigid and reproducible solution to treat ankle arthritis. With a plate fixation it might be possible to treat more complex deformities and provide additional stability in compromised patients. This study documents the early outcomes on the use of an anterior plate for patients undergoing an ankle arthrodesis. Methods: All ankle fusions using the anterior plate at our center were included and followed. Fifty-one patients (53 ankles) presented to the senior author between September 2014 and February 2017. Patients experienced ongoing ankle pain due to degenerative changes, a previous ankle fusion, post-traumatic arthritis (PTA) or failure of a total ankle arthroplasty (TAA). All patients’ medical and ankle surgical history was documented. This study was conducted in compliance and approved with a local IRB. Outcomes were evaluated pre-operatively and post-operatively with the Veterans Rand Health Survey (VR-12), Ankle Osteoarthritis Scale (AOS) and Visual Analog Scale (VAS) Pain scale. A patient satisfaction survey was distributed to all patients and results were tabulated. Average follow up for outcome scores 16.8 months (range 6 – 38 months). Results: Fifty-one patients(29 females) with the mean age of 56.56 years(26.3–74.8) had a mean follow-up of 16.6months(6– 38months). Diagnoses included 17 primary, 10 revision, 6 TAA failures and 20 PTA. 86.3%(44 patients) were non-diabetic. Non-smokers included 43.1%(22). VR-12 Physical improved from 29.46 to 37.72, and Mental 47.34 to 52.55 pre-operatively to post-operatively, respectively. AOS Pain improved: 462.41 to 252.8; AOS Disability: 567.52 to latest 387.77. Mean VAS improved from pre-operatively of 54.28 to latest of 30.61. Arthrodesis rate was 98%(52/53 ankles). 45 ankles were fused at 3 months by x-rays. Symptomatic patients (with pain) had a CT scan done at a minimum of 3 months (1/8 CT scans showed non-union &amp; 7 were fused). Major complications were 3.8%(2 patients). There were no wound complications. Conclusion: An anterior plate construct is more invasive compared to arthroscopic or other arthrodesis options. However, the stability of the construct allows for a reliable option in complex situations, and the arthrodesis rate appears to be exceptional. In this complex patient population, the arthrodesis rate was 98%, while major complications only 4%. Summary Sentence: Anterior plate construct is more invasive compared to arthroscopic/other arthrodesis options. However, stability of the construct allows for a reliable option and fusion rates seem to be exceptional.

Biomechanical Stability of a Stand-Alone Interbody Spacer in Two-Level and Hybrid Cervical Fusion Constructs.

Study Design:In vitro human cadaveric biomechanical analysis.Objective:To evaluate the segmental stability of a stand-alone spacer (SAS) device compared with the traditional anterior cervical plate (ACP) construct in the setting of a 2-level cervical fusion construct or as a hybrid construct adjacent to a previous 1-level ACP construct.Methods:Twelve human cadaveric cervical spines (C2-T1) were nondestructively tested with a custom 6-degree-of-freedom spine simulator under axial rotation (AR), flexion-extension (FE), and lateral bending (LB) at 1.5 N m loads. After intact analysis, each specimen underwent instrumentation and testing in the following 3 configurations, with each specimen randomized to the order of construct: (A) C5-7 SAS; (B) C5-6 ACP, and C6-7 SAS (hybrid); (C) C5-7 ACP. Full range of motion (ROM) data at C5-C7 was obtained and analyzed by each loading modality utilizing mean comparisons with repeated measures analysis of variance with Sidak correction for multiple comparisons.Results:Compared with the intact specimen, all tested constructs had significantly increased segmental stability at C5-C7 in AR and FE ROM, with no difference in LB ROM. At C5-C6, all test constructs again had increased segmental stability in FE ROM compared with intact (10.9° ± 4.4° Intact vs SAS 6.6° ± 3.2°, P < .001; vs.Hybrid 2.9° ± 2.0°, P = .005; vs ACP 2.1° ± 1.4°, P < .001), but had no difference in AR and LB ROM. Analysis of C6-C7 ROM demonstrated all test groups had significantly greater segmental stability in FE ROM compared with intact (9.6° ± 2.7° Intact vs SAS 5.0° ± 3.0°, P = .018; vs Hybrid 5.0° ± 2.7°, P = .018; vs ACP 4.4° ± 5.2°, P = .005). Only the hybrid and 2-level ACP constructs had increased stability at C6-C7 in AR ROM compared with intact, with no difference for all test groups in LB ROM. Comparison between test constructs demonstrated no difference in C5-C7 and C6-C7 segmental stability in all planes of motion. However, at C5-C6 comparison between test constructs found the 2-level SAS had significantly less segmental stability compared to the hybrid (6.6° ± 3.2° vs 2.9° ± 2.0°, P = .025) and ACP (6.6° ± 3.2° vs 2.1° ± 1.4°, P = .004).Conclusions:Our study found the currently tested SAS device may be a reasonable option as part of a 2-level hybrid construct, when used below an adjacent 1-level ACP, but should be used with careful consideration as a 2-level SAS construct. Consequences of decreased segmental stability in FE are unknown; however, optimal immediate fixation stability is an important surgical principle to avoid loss of fixation, segmental kyphosis, interbody graft subsidence, and pseudarthrosis.

Locking stand-alone cages versus anterior plate constructs in single-level fusion for degenerative cervical disease: a systematic review and meta-analysis.

To conduct a meta-analysis to compare the clinical and radiological outcomes in single-level anterior cervical discectomy and fusion (ACDF) surgery for degenerative cervical disease performed by either single-level locking stand-alone cage (LSC) or anterior plate construct (APC). We performed a comprehensive database search of Medline, PubMed, EMBASE and Cochrane Database of Systematic Reviews according to PRISMA guidelines and identified six articles that satisfied our inclusion criteria. We excluded all non-English language articles and articles which did not directly compare LSC and APC. Only papers which focussed on single-level ACDF were included in the study. There were no significant differences in blood loss, clinical outcomes (JOA, VAS, NDI scores) or radiological outcomes (cervical lordosis, segmental Cobb angle, subsidence and fusion) between the two groups. Operative time was significantly shorter in the LSC group (MD 7.2min, 95% CI 0.3-14.1, p=0.04). APC was associated with a statistically significant increase in dysphagia in the follow-up period (OR 6.2, 95% CI 1.0-36.6, p=0.05). LSC and APC have similar clinical and radiological outcomes. Further blinded randomised trials are required to establish conclusive evidence in favour of LSC with regards to minimising post-operative dysphagia. We also encourage future studies to make use of formalised dysphagia outcome measures in reporting complications.

Anterior Cervical Discectomy and Fusion (ACDF): Comparison Between Zero Profile Implants and Anterior Cervical Plate and Spacer.

Introduction: Interposition grafts combined with anterior plating currently remain the gold standard for anterior cervical discectomy and fusion. The use of anterior plates increases fusion rates but may be associated with higher rates of postoperative dysphagia. The aim of the current study was to determine the clinical and radiological outcomes following anterior cervical discectomy and fusion (ACDF) using zero-profile anchored spacers versus standard interposition grafts with anterior plating.Methods: This was a retrospective case series. A total of 53 male and 51 female consecutive patients (164 total operated levels) who underwent ACDF between 2007 and 2011 were included. The mean clinical follow-up was 15.7 ± 1.2 (SEM) months for patients with zero-profile implants and 14.8 ± 2.1 months for patients with conventional ACDF with anterior plating. Patient demographics, operative details, clinical outcomes, complications, and radiographic imaging were reviewed. Dysphagia was determined using the Bazaz criteria.Results: Clinical outcome scores improved in both groups as measured by the modified Japanese Orthopedic Association and Nurick scores. Zero-profile constructs gave rise to significantly less prevertebral soft tissue swelling compared to constructs with anterior plates postoperatively (15.74 ± 0.52 as compared to 20.48 ± 0.85 mm, p < 0.001) and at the latest follow-up (10.88 ± 0.39 mm vs. 13.72 ± 0.67 mm, p < 0.001). There was a significant difference in the incidence of dysphagia at the latest follow-up (1.5% vs. 20%, p=0.001, zero-profile vs. anterior plate, respectively).Conclusion: Zero-profile implants lead to functional outcomes similar to standard anterior plate constructs. Avoiding the use of an anterior locking plate may decrease the risk of persistent postoperative dysphagia.

Plate Construct versus Stand-Alone Cage in ACDF. Does the Plate Maintain a Sagittal Plane Correction: Clinical Outcome and Radiological Findings Correlation

Introduction Anterior cervical discectomy and fusion (ACDF) is the treatment of choice of cervical degenerative disc disease which cause neurological symptoms include radiculopathy and myelopathy, and it can be done by different techniques which includes several options for implants like disc spacers made of autograft or allograft bone, porous metal, polyether ether ketone (PEEK) and anterior plates and screws. The purpose of this study is to compare the role of anterior plate constructs (ACDF-CPC) and stand-alone cage (ACDF-CA) in maintain of Sagittal plane correction, clinical and radiological findings. Material and Methods Retrospective study of 24 patients who underwent ACDF in Hamad General Hospital, 16 cases with ACDF-CA and 8 cases ACDF-CPC. Radiological findings (cervical lordosis, segmental lordosis, cage subsidence, disc height) and clinical outcome (Odom's criteria, dysphagia and swallowing problems) are compared (pre-op, 3–6 months post op, 12–18 months post op). Results Cervical Lordosis, segmental lordosis, and disc space height at the operated levels increased an average of 5.4°, 3.1°, and 1.5 mm in ACDF-CA and 3.2°, 3.4°, 3.5 mm in ACDF-CPC, with good to excellent result in ACDF-CA and fair to good result in ACDF-CPC according to Odom's criteria, with more dysphagia and dysphonia in ACDF-CPC. The maintaining of sagittal plane correction, disc space height, and cage subside are decrease during follow up in both groups, but clinical outcome was stable in most of the cases comparing to immediate post op finding. Conclusion Anterior cervical discectomy and fusion by stand-alone cage or anterior plate is achieved good clinical outcome and significant correction in sagittal plane and disc space height, but no significant difference between two groups in maintaining the sagittal plane correction and disc space.

Magnetic resonance imaging artifact following anterior cervical discectomy and fusion with a trabecular metal cage.

This study was undertaken to evaluate the impact of postoperative MRI artifact on the assessment of ongoing spinal cord or nerve root compression after anterior cervical discectomy and fusion (ACDF) using a trabecular tantalum cage or bone autograft or allograft. The authors conducted a retrospective review of postoperative MRI studies of patients treated surgically for cervical disc degenerative disease or cervical instability secondary to trauma. Standard ACDF with either a trabecular tantalum cage or interbody bone graft had been performed. Postoperative MR images were shown twice in random order to each of 3 assessors (2 spine surgeons, 1 neuroradiologist) to determine whether the presence of a tantalum interbody cage and/or anterior cervical fixation plate or screws imparted MRI artifact significant enough to prevent reliable postoperative assessment of ongoing spinal cord or nerve root compression. A total of 63 patients were identified. One group of 29 patients received a tantalum interbody cage, with 13 patients (45%) undergoing anterior plate fixation. A second group of 34 patients received bone auto- or allograft, with 23 (68%) undergoing anterior plate fixation. The paramagnetic implant construct artifact had minimal impact on visualization of postoperative surgical level spinal cord compression. In the cage group, 98% (171/174) of the cases were rated as assessable versus 99% in the bone graft group (201/204), with high intraobserver reliability. In contrast, for the assessment of ongoing surgical level nerve root compression, the presence of a tantalum cage significantly decreased visualization of nerve roots to 70% (121/174) in comparison with 85% (173/204) in the bone graft group (p < 0.001). When sequences using turbo spin echo (TSE), a T2-weighted axial sequence, were acquired, nerve roots were rated as assessable in 88% (69/78) of cases; when only axial T2-weighted sequences were available, the nerve roots were rated as assessable in 54% (52/96) of cases (p < 0.01). The presence of anterior plate fixation had minimal impact on visualization of the spinal cord (99% [213/216] for plated cases vs 98% [159/162] for nonplated cases; p = 1.0) or nerve roots (79% [170/216] for plated cases vs 77% [124/162] for nonplated cases; p = 0.62). Interbody fusion with tantalum cage following anterior cervical discectomy imparts significant paramagnetic artifact, which significantly decreases visualization and assessment of ongoing surgical level nerve root, but not spinal cord, compression. Anterior plate constructs do not affect visualization of these structures. TSE T2-weighted sequences significantly improve nerve root visualization and should be performed as part of a standard postoperative protocol when imaging the cervical spine following interbody implantation of materials with potential for paramagnetic artifact.

Biomechanical Stability of the Stalif-C Stand-Alone Spacer in Multi-level and Hybrid Cervical Fusion Constructs

Introduction Anterior plate constructs for cervical discectomy and fusion have been linked to postoperative dysphagia, increased operative times, and wider surgical exposures. Several “low profile” integrated stand-alone spacers (SAS) have been developed. While these spacers have demonstrated successful clinical outcomes and similar biomechanical stability to anterior plate constructs in single-level fusions, their biomechanical stability in multi-level constructs has not yet been established. Methods Twelve human cadaveric cervical spines (C2-T2) were nondestructively tested with a six-degree-of-freedom simulator under axial rotation (AR), flexion-extension (FE), and lateral bending (LB) loading. After intact analysis, each specimen underwent sequential instrumentation and testing: (A) C5-6 spacer/plate with C6-7 SAS; (B) C5-7 SAS; (C) C5-7 spacer/plate. Range of motion (ROM) data was obtained and analyzed with paired t-tests and Bonferroni correction. Results The 2-level plate construct significantly reduced flexion-extension ROM compared to the 2-level SAS (5.6 ± 3.4 degrees versus 11.6 ± 4.6 degrees, respectively; p &lt; 0.05). There was a significantly increased segmental ROM in the 2-level SAS construct compared to the 2-level hybrid construct in flexion-extension as well (11.6 ± 4.6 degrees versus 7.2 ± 2.4 degrees, respectively, p &lt; 0.05). There was no significant difference in lateral bending and axial rotation ( p &gt; 0.05) between the three different 2-level constructs. Conclusions Our study found that hybrid and 2-level SAS constructs are comparable to conventional anterior plate constructs in lateral bending and axial rotation, but there was an increase in flexion-extension motion allowed with constructs that incorporated a SAS. Stand-alone cervical spacers with integrated screws for hybrid and 2-level SAS constructs are reasonable alternatives to two-level plate fixation; however, clinical trials are necessary to determine if the increased ROM in flexion-extension noted in the SAS constructs translates to clinical outcome.

Anterior Cervical Discectomy and Fusion: Comparison between Zero-Profile Implants and Anterior Cervical Plate and Spacer

Introduction Interposition grafts combined with anterior plating currently remain the gold standard for anterior cervical discectomy and fusion. The use of anterior plates increases fusion rates, but may be associated with higher rates of postoperative dysphagia. The current study aimed to compare the clinical and radiological outcomes following anterior cervical discectomy and fusion (ACDF) using zero-profile anchored spacers versus standard interposition grafts with anterior plating. Materials and Methods This was a retrospective case series. A total of 53 male and 51 female consecutive patients (164 total operated levels) who underwent ACDF between 2007 and 2011 were included. The mean clinical follow-up was 15.7 ± 1.2 months (SEM) for patient with zero-profile implants and 14.8 ± 2.1 months for patients with conventional ACDF with anterior plating. Patient demographics, operative details, clinical outcomes, complications, and radiographic imaging were reviewed. Dysphagia was determined using Bazaz criteria. Results Clinical outcome scores were similar between the two groups as measured by the modified JOA and Nurick scores. Zero-profile constructs gave rise to significantly less prevertebral soft-tissue swelling compared with constructs with anterior plates postoperatively (15.74 ± 0.52 vs. 20.48 ± 0.85 mm, p &lt; 0.001, respectively) and at the latest follow-up (10.88 ± 0.39 vs. 13.72 ± 0.67 mm, p &lt; 0.001, respectively). At latest follow-up, there was a significantly lower incidence of dysphagia associated with utilization of zero-profile constructs as compared with anterior plate (1.5 vs. 20%, p = 0.001, respectively). Conclusion Zero-profile implants lead to functional outcomes similar to standard anterior plate constructs. Avoiding the use of anterior locking plate may decrease the risk of postoperative dysphagia.

Early Radiographic and Clinical Outcomes Study Evaluating an Integrated Screw and Interbody Spacer for One- and Two-Level ACDF

Multiple techniques and implants can be used in ACDF, the newest of which are integrated cage and screw constructs. These devices may be beneficial over anterior plate constructs due to a negligible anterior profile that may reduce dysphagia. The goal of this study is to review the early radiographical and clinical results associated with a low profile integrated intervertebral cage in one- and two-level anterior column fusions. Fusion rates, incidence of hardware failure and deformity correction were assessed through 1 year. Patientreported scores, including VAS for neck pain, and improvements in axial neck pain and neurologic deficit from the preoperative baseline were quantified at 3, 6 and 12 months post-operatively. The incidence of dysphagia was recorded. Lordosis and disc space height at the operated levels increased an average of 4.5° and 3.3mm after device placement (p<0.001). Sagittal plane correction was maintained at 1 year. VAS improved from an average of 5.1 preoperatively to 3.1 immediately postoperatively and was maintained at 12 months. At 3 months, patient-reported improvements in axial neck pain and neurologic deficit were 85% and 93%, respectively. Reported improvements were sustained for both parameters at 12 months (77% and 86%, respectively). Fusion was noted in 93% of the operated levels. There were two documented cases of dysphagia that lasted more than 5 weeks, both following two level ACDFs with the test device (3.5% rate of chronic dysphagia). The low profile integrated device improved lordosis at the operated level that was maintained at 1 year. Fusion rates with the new device are consistent with ACDF using anterior plating. In combination with improvements in pain and a minimal rate of dysphagia, study findings support the use of integrated interbody spacers for use in one- and two-level ACDF procedures. Level IV, Case Series.

Biomechanical evaluation of a biomimetic spinal construct

BackgroundLaboratory spinal biomechanical tests using human cadaveric or animal spines have limitations in terms of disease transmission, high sample variability, decay and fatigue during extended testing protocols. Therefore, a synthetic biomimetic spine model may be an acceptable substitute. The goal of current study is to evaluate the properties of a synthetic biomimetic spine model; also to assess the mechanical performance of lateral plating following lateral interbody fusion.MethodsThree L3/4 synthetic spinal motion segments were examined using a validated pure moment testing system. Moments (±7.5 Nm) were applied in flexion-extension (FE), lateral bending (LB) and axial rotation (AR) at 1Hz for total 10000 cycles in MTS Bionix. An additional test was performed 12 hours after 10000 cycles. A ±10 Nm cycle was also performed to allow provide comparison to the literature. For implantation evaluation, each model was tested in the 4 following conditions: 1) intact, 2) lateral cage alone, 3) lateral cage and plate 4) anterior cage and plate. Results were analysed using ANOVA with post-hoc Tukey’s HSD test.ResultsRange of motion (ROM) exhibited logarithmic growth with cycle number (increases of 16%, 37.5% and 24.3% in AR, FE and LB respectively). No signification difference (p > 0.1) was detected between 4 cycles, 10000 cycles and 12 hour rest stages. All measured parameters were comparable to that of reported cadaveric values. The ROM for a lateral cage and plate construct was not significantly different to the anterior lumbar interbody construct for FE (p = 1.00), LB (p = 0.995) and AR (p = 0.837).ConclusionsBased on anatomical and biomechanical similarities, the synthetic spine tested here provides a reasonable model to represent the human lumbar spine. Repeated testing did not dramatically alter biomechanics which may allow non-destructive testing between many different procedures and devices without the worry of carry over effects. Small intra-specimen variability and lack of biohazard makes this an attractive alternative for in vitro spine biomechanical testing. It also proved an acceptable surrogate for biomechanical testing, confirming that a lateral lumbar interbody cage and plate construct reduces ROM to a similar degree as anterior lumbar interbody cage and plate constructs.