Stand-alone Cage Research Articles

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.

Postoperative Outcomes and Complications after Anterior Cervical Discectomy and Interbody Fusion with a Self-locking Stand-alone Cage

Postoperative Outcomes and Complications after Anterior Cervical Discectomy and Interbody Fusion with a Self-locking Stand-alone Cage

Self-Locking Stand-Alone Cage Used from Opposite Approach for the Treatment of Adjacent Segment Disease After an Anterior Cervical Corpectomy and Fusion.

To investigate the efficacy and safety of the self-locking stand-alone cage used from opposite approach for the treatment of adjacent segment disease (ASD) after an anterior cervical corpectomy and fusion (ACCF). In this study, we retrospectively analyzed the clinical data of 8 cases of ACCF in the treatment of ASD cervical spondylopathy. All patients received self-locking stand-alone cage treatment. At different time points, the clinical status was evaluated using the Japan Orthopedic Association (JOA) score, JOA recovery rate (RR), and Neck Disability index (NDI) score. X-ray measurements included C2-C7 Cobb angle, fusion segment angle (FSA), cervical vertebral bow depth (VBP), and height of surgical segment (HOS). Statistical imaging parameters of sagittal cervical spine. Bone graft fusion in all self-locking stand-alone cage segments was evaluated. All operations were successfully completed, and no infection, epidural hematoma, or rupture of the dura mater were observed in all patients. Compared with pre-operation, the JOA and NDI scores at 3 months and at the last follow-up were significantly improved (p < 0.05). The JOA recovery rate between the final follow-up and preoperatively was 64.8±5.2%. One patient had dysphagia postoperatively, but was resolved after 3 months. Three months after surgery, the sagittal radiographic outcomes improved significantly and were well maintained during the final follow-up. The self-locking stand-alone cage is a reliable and effective method used from the opposite approach for the treatment of ASD after ACCF in terms of JOA and NDI scores. The cervical alignment correction is considered satisfactory.

P116. Swallowing function following anterior cervical discectomy and fusion with and without anterior plating

BACKGROUND CONTEXT Anterior cervical plating in anterior cervical discectomy and fusion (ACDF) procedures are associated with improved outcomes compared to stand-alone cages. However, concerns exist regarding increased rates of postoperative dysphagia following an ACDF. PURPOSE To quantify the effect of anterior plating on SWAL-QOL scores and radiographic swelling assessments following a primary, single-level ACDF. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE A total of 68 patients who underwent a primary, single-level ACDF from 2014-2017. OUTCOME MEASURES SWAL-QOL scores, radiographic swelling. METHODS Patients were retrospectively reviewed and grouped by those receiving a stand-alone cage (cage) or cage with anterior plating (plate). SWAL-QOL scores were recorded preoperatively and 6-week and 12-week postoperatively. Lateral radiographs were used to create a swelling index with a ratio of the prevertebral swelling distance to the anterior-posterior diameter of each involved vertebral body. A tracheal air index was created using the same methodology. Statistical analysis was performed using chi-square analysis and independent t-tests for categorical and continuous variables. RESULTS A total of 68 primary, single-level ACDF patients were included. Forty-one (60.3%) received a stand-alone cage and 27 (39.7%) received a cage with anterior plating. No differences in demographics, comorbidities, operative time, estimated blood loss, or length of hospital stay were identified between cage and plate cohorts. Additionally, no differences were observed in postoperative SWAL-QOL scores. Swelling index was greater for the plate cohort at 6-weeks but was similar between groups at 12-weeks. The air index was similar at all time points. CONCLUSIONS The results demonstrate that patients undergoing a primary, single-level ACDF with or without anterior plating experience similar operative times and lengths of stay. Patients that receive a cage with anterior plating did not experience significant increases in dysphagia as measured by the SWAL-QOL questionnaire compared to patients that received a stand-alone cage. Furthermore, radiographic assessments of swelling are comparable between cohorts. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Reoperation rate after anterior cervical discectomy and fusion using standalone cages in degenerative disease: a study of 2,078 cases

BACKGROUND CONTEXTOver the last two decades, there has been a rapid increase in the use of cervical spine interbody fusion cages. Reoperation rate remains an important determinant of procedural efficacy and safety. PURPOSETo evaluate the rate and reasons for reoperations in cervical spondylosis patients undergoing anterior decompression and fusion using stand-alone cervical interbody fusion cages. STUDY DESIGNA retrospective study of 2,078 consecutive cases of degenerative cervical spine disease undergoing fusion using stand-alone cages. PATIENT SAMPLEBetween January 2005 and December 2014, 2,078 patients underwent anterior cervical decompression and fusion using stand-alone cages in our institution. OUTCOME MEASURESThe reoperations were analyzed and classified into early (during the first 90 days postoperatively) and late (after 90 days) reoperations. The rate and the causes of reoperation in both groups were reported and the results were compared. METHODSIn 1,558 patients, a short segment fusion (≤2 levels) was performed, while the remaining 520 patients underwent a long segment fusion (≥3 levels). RESULTSThe overall incidence of reoperation was 5.63%. The rate of early reoperations was 2.07%, mostly due to postoperative hematoma, and the rate of late reoperations was 3.56%, mostly due to adjacent segment disease. Revision due to pseudarthrosis was performed in 0.58% of cases. The early reoperation rate was significantly higher in the group with a long segment fusion, while the late reoperation rate was significantly higher in patients undergoing a short segment fusion. CONCLUSIONFollowing anterior cervical decompression and fusion with a stand-alone cage, the overall incidence of symptomatic pseudarthrosis is low. Patients undergoing long segment fusion should be closely observed in the early postoperative period as they have a higher early complication rate. On the other hand, long segment fusions have a lower incidence of adjacent segment disease over the years.

Swallowing Function Following Anterior Cervical Discectomy and Fusion With and Without Anterior Plating: A SWAL-QOL (Swallowing-Quality of Life) and Radiographic Assessment.

ObjectiveAnterior cervical plating in anterior cervical discectomy and fusion (ACDF) procedures are associated with improved outcomes compared to stand-alone cages. However, concerns exist regarding increased rates of postoperative dysphagia following an ACDF. This study aims to quantify the effect of anterior plating on swallowing-quality of life (SWAL-QOL) scores and radiographic swelling assessments following a primary, single-level ACDF. MethodsPatients retrospectively reviewed. Patients grouped into those receiving a cage or anterior plate. SWAL-QOL scores were recorded preoperatively and 6 weeks and 12 weeks postoperatively. Lateral radiographs were used to create a swelling index with a ratio of the prevertebral swelling distance to the anterior-posterior diameter of each involved vertebral body. An air index was created using the same methodology. Statistical analysis was performed using chi-square analysis and independent t-tests for categorical and continuous variables. ResultsSixty-eight primary, single-level ACDF patients were included. Forty-one (60.3%) received a stand-alone cage and 27 (39.7%) received a cage with anterior plating. No differences in demographics, comorbidities, operative time, estimated blood loss, or length of hospital stay were identified between Cage and Plate cohorts. Finally, no differences were observed in postoperative SWAL-QOL scores or swelling and air indices between groups. ConclusionThe results demonstrate that patients undergoing a primary, single-level ACDF with or without anterior plating experience similar operative times and lengths of stay. Patients that receive a cage with anterior plating did not experience significant increases in dysphagia as measured by the SWAL-QOL questionnaire compared to patients that received a stand-alone cage. Furthermore, radiographic assessments of swelling are comparable.

Is there any advantage of using stand-alone cages? A numerical approach

BackgroundSegment fusion using interbody cages supplemented with pedicle screw fixation is the most common surgery for the treatment of low back pain. However, there is still much controversy regarding the use of cages in a stand-alone fashion. The goal of this work is to numerically compare the influence that each surgery has on lumbar biomechanics.MethodsA non-linear FE model of the whole lumbar spine was developed to compare between two types of cages (OLYS and NEOLIF) with and without supplementary fixation. The motion of the whole spine was analysed and the biomechanical environment of the adjacent segments to the operated one was studied. Moreover, the risk of subsidence of the cages was qualitatively evaluated.ResultsA great ROM reduction occurred when supplementary fixation was used. This stiffening increased the stresses at the adjacent levels. It might be hypothesised that the overloading of these segments could be related with the clinically observed adjacent disc degeneration. Meanwhile, the stand-alone cages allowed for a wider movement, and therefore, the influence of the surgery on adjacent discs was much lower. Regarding the risk of subsidence, the contact pressure magnitude was similar for both intervertebral cage designs and near the value of the maximum tolerable pressure of the endplates.ConclusionsA minimally invasive posterior insertion of an intervertebral cage (OLYS or NEOLIF) was compared using a stand-alone design or adding supplementary fixation. The outcomes of these two techniques were compared, and although stand-alone cage may diminish the risk of disease progression to the adjacent discs, the spinal movement in this case could compromise the vertebral fusion and might present a higher risk of cage subsidence.

Locking Stand-Alone Cage Constructs for the Treatment of Cervical Spine Degenerative Disease.

Study DesignProspective case series study.PurposeDescription of the outcome of stand-alone cervical cages for single and multilevel cervical degenerative spine disease.Overview of LiteratureThe aim of anterior cervical discectomy and fusion (ACDF) for cervical spine disease is to improve patient symptoms and spine stability and restore lordosis. Locking stand-alone cages were developed with the goal of minimizing soft tissue disruption anterior to the vertebrae and reducing the profile of the construct by avoiding an anterior plate, thereby maximizing ACDF benefits.MethodsThis study comprises a case series of patients surgically treated between July 2015 and February 2018 who received single or multilevel ACDF with a zero-profile stand-alone cervical cage. Surgical and clinical preoperative evaluation and surgical outcomes were evaluated using pre- and postoperative Nurick, Visual Analog Scale (VAS), Neck Disability Index (NDI), Japanese Orthopedic Association (JOA) score for myelopathy scales, cervical Cobb angles, postoperative surgical complications, and fusion and subsidence rates.ResultsFifty-three patients underwent ACDF; the mean age of these patients was 58.8 years, and their preoperative VAS, NDI, and JOA scores were 8.1, 31.6, and 15.3, respectively. The preoperative Cobb angle was 30.7°. Forty-five percent of patients had one-level, 54.7% had two-level, and 13.2% had three-level procedures. On preoperative magnetic resonance imaging, foraminal stenosis was present in 94.3% of patients, whereas medullar stenosis was present in 41.5%. The rate of complications was 5.7%: two patients had postoperative dysphagia (3.7%), and one patient had a surgical site hematoma. Mean postoperative follow-up time was 6.7 months; postoperative VAS, NDI, and JOA scores were 2.4, 15.9, and 15.8, respectively. Postoperative Cobb angle was 35.9°, fusion rate was 84.9%, and subsidence rate was 11.3%.ConclusionsACDF with zero-profile stand-alone cervical devices is an excellent option for cervical degenerative disc disease of one, two, and three levels, with similar results reported when using ACDF with either cage or plate.

Segmental Motion of the Cervical Spine After Total Disc Replacement Using ActivC Versus Discectomy and Fusion Using Stand-alone Cage

Anterior cervical discectomy and fusion (ACDF) has been a widely accepted procedure for the treatment of cervical disc diseases. However, due to several reports regarding postfusion exacerbation of adjacent segments, a motion-preserving prosthesis was developed. In the present retrospective analysis, total disc replacement (TDR) using ActivC (Aesculap AG, Tuttlingen, Germany) was compared with ACDF using a stand-alone cage. Among patients diagnosed with cervical disc diseases, those who received either ACDF or TDR at a single level between C3 and C7 from January 2010 to December 2015 were reviewed. Clinical outcomes were assessed using the visual analogue scale for arm and neck pain and the neck disability index. Clinical scales, lateral neutral, and flexion-extension radiographs were taken for all patients preoperatively and 2 months, 6 months, 1 year, and 2 years postoperatively. Global lordosis, C2-C7 Sagittal vertical axis, and T1 slope were measured on lateral neutral radiographs. The segmental range of motion (ROM) of the operated level, cranial adjacent level, and caudal adjacent level were defined as the difference between Cobb angles on flexion-extension lateral radiographs. A total of 53 patients (mean age 48.5 years) were reviewed. Thirty patients were treated with ACDF and the remaining 23 patients received TDR. At the 2-year follow-up, the segmental ROM of operated level was significantly preserved in the TDR group compared with the ACDF group (P= 0.007). Conversely, no significant differences in the ROM at the adjacent segments were observed between the TDR and ACDF groups (P > 0.05). The clinical outcome was excellent in both ACDF and TDR groups and was maintained until the 2-year follow-up. In the present study, TDR using ActivC showed successful motion preservation at the operated level and equivalent results were observed with ACDF based on clinical and radiologic results.

Dynamic Fusion Process in the Anterior Cervical Discectomy and Fusion with Self-Locking Stand-Alone Cages

Self-locking stand-alone cages can achieve satisfactory clinical results and fusion rate. However, there have been no reports on the causes and relationship of different fusion state. This study is to classify the different fusion states of the index level and to explore the potential contributing factors and links of them. From June 2008 to October 2011, 42 patients underwent anterior cervical discectomy and fusion with MC+ cages. More than 5 years' follow-up was reviewed. The fusion state and the relevant clinical and radiologic records were reviewed retrospectively. At the last follow-up, the fusion proportion of type I, II, III, and IV was 11.7%, 16.9%, 26.9%, and 42.9%, respectively. The overall fusion rate was 97.4%. For all the fused types, significant improvement for the visual analog scale, Japanese Orthopaedic Association, and Neck Disability Index scores was found at the last follow-up (P<0.05). However, there were no significant differences between the 4 types (P > 0.05). For sagittal vertical axis, type IV was significantly larger than that of type I, II, and III (P < 0.05), and for range of motion, type III was significantly larger than that of type II and IV (P < 0.05). For anterior cervical discectomy and fusion with self-locking stand-alone cages, the fusion of the index level seems to be a progressive dynamic process during the mid-term follow-up, which may be influenced by the location of the cage, the aagittal vertical axis of the index level, and the global range of motion of the cervical spine. Satisfactory clinical results could be achieved by all the fused types.

The impact of adding posterior instrumentation to transpsoas lateral fusion: a systematic review and meta-analysis.

OBJECTIVETranspsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumentation posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors' knowledge, the literature on comparison of the two approaches is sparse.METHODSThe authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guidelines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP).RESULTSA total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confidence interval [CI] 0.04-0.11) compared to TPP (0.03, 95% CI 0.01-0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10-0.26) compared to TPP (0.03, 95% CI 0.00-0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient deficits were found to be comparable between the two groups.CONCLUSIONSThese results appear to suggest that addition of posterior instrumentation to transpsoas fusion is associated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique.

Comparison of Clinical and Radiologic Outcomes Between Self-Locking Stand-Alone Cage and Cage with Anterior Plate for Multilevel Anterior Cervical Discectomy and Fusion: A Meta-Analysis

This meta-analysis was conducted to evaluate the therapeutic effects in clinical and radiologic outcomes of a self-locking stand-alone cage (SSC) and cage-with-plate (CP) for multilevel anterior cervical discectomy and fusion (ACDF). A systematic search was performed for all comparative studies reported up to August 2018. Operative time, hospital stay, intraoperative blood loss, Japanese Orthopedic Association score, Neck Disability Index (NDI), cervical and segmental Cobb angle, intervertebral height, fusion rate, incidence of subsidence, dysphagia, and adjacent segment degeneration were analyzed with the RevMan 5.3.3 software. A total of 15 studies were included. There was no difference regarding preoperative or postoperative Japanese Orthopedic Association score, Neck Disability Index, segmental Cobb angle and intervertebral height, preoperative cervical Cobb angle, fusion rate, incidence of subsidence, and adjacent segment degeneration between the SSC and CP group (P > 0.05). However, the SSC group had shorter operative time (mean difference [MD],-11.35; 95% confidence interval [CI],-16.24 to-3.66) and hospital stay (MD,-0.64; 95% CI,-1.21 to-0.06), less intraoperative blood loss (MD,-13.22; 95% CI,-19.03 to-7.41) and postoperative cervical Cobb angle (MD,-0.70; 95% CI,-1.35 to-0.06), and lower incidence of dysphagia significantly (odds ratio,-0.57; 95% CI, 0.40-0.82) (P < 0.05). ACDF with SSC and CP in multilevel cervical spondylosis achieved similar clinical relief. Although CP maintained better cervical lordosis, SSC contributed to less surgical pain and fewer complications. ACDF with SSC is safe and efficient in treating multilevel cervical spondylosis.

Can Self-Locking Cages Offer the Same Clinical Outcomes as Anterior Cage-with-Plate Fixation for 3-Level Anterior Cervical Discectomy and Fusion (ACDF) in Mid-Term Follow-Up?

BackgroundSelf-locking stand-alone cages (MC+) and cage-with-pate fixation system are 2 different surgical methods used in anterior cervical discectomy and fusion (ACDF), but few systematic comparative studies comparing the 2 methods in treating multilevel cervical spondylotic myelopathy (MCSM) have been published.Material/MethodsSixty-two patients with MCSM who underwent multilevel ACDF were enrolled and completed at least a 3-year postoperative follow-up. The operative time, intra-operative blood loss, and clinical and radiological results were compared between the MC+ self-locking cages group and the cage-with-plate fixation group. Clinical parameters, including VAS for neck pain, Japanese Orthopedic Association (JOA) score, and neck disabled index (NDI), were evaluated. Surgical results according to Odom’s criteria and postoperative dysphagia status, C5 nerve root palsy, and loosening of the instrumentation were recorded. Postoperative radiological results, including fusion rates, fusion segmental Cobb’s angle (FSC), cervical lordosis, fusion segmental height (FSH), cage subsidence, and adjacent segment degeneration, were assessed.ResultsThe VAS score, JOA score, and NDI score were significantly improved in both groups. However, the patients in the cage-with-plate group were more likely to have neck pain at the last follow-up. The cervical lordosis, FSC, and FSH showed significant correction immediately after surgery. The loss of the cervical lordosis and FSH were higher in the MC+ group.ConclusionsWe found that use of MC+ cages is safe and effective in treating MCSM, but for patients who require strong postoperative stabilization and maintaining the cervical alignment better, the cage-with-plate fixation may best.

Integrated screws with cage spacer system in the treatment of cervical spine degenerative disease with a minimum follow-up of 2 years

Background: Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical treatment for cervical degenerative disease.Integrated screws with cage spacer system is a relatively new device designed for patients undergoing ACDF with the dual properties of plating and standalone cage. We are reporting our findings in term of clinico-radiological outcomes following the use of such devices in the treatment of cervical spine degenerative diseases. Materials and Methods: Retrospectively, we studied 18 patients treated with integrated screws and cage spacer system for cervical degenerative diseases with a minimum follow up period of 2 years.We compared the preoperative Visual analogue scale (VAS) pain score both neck and for arm, neck disability index (NDI), overall cervical sagittal alignment (OSA) and segmental sagittal alignment (SSA) with the postoperative data. The final outcome was assessed with Odom's criteria. Paired student t test was used for statistical analysis. Results: The mean age of the patient was 46 years (range: 29-63 years) with the mean follow up period of 28 months (range: 24-47 months). The total operated levels were 19.Out of which 11 were at C5-C6 level. The mean pain VAS score for neck and arm along with NDI improved significantly after surgery at last follow up. The mean OSA and SSA improved from 8.00 ± 5.00 to 10.61 ± 3.50 and 3.50 ± 3.20 to 8.11 ± 4.65 at last follow up. X ray showed 100% fusion rate and majority of the patients had a good outcome. Conclusion: Integrated screws and cage spacer device is a safe and effective alternative for the treatment of cervical degenerative diseases.

Comparative Study between Single-Level Anterior Cervical Discectomy and Fusion using Cage and Plate or Cage Alone

Background: anterior cervical discectomy and interbody fusion (ACDF) is a well-accepted management option for the treatment of persistent cervical radiculopathy or myelopathy due to cervical disc prolapse. Typically a fusion is performed to stabilize the segment, maintain foraminal height. Objective: to prospectively analyze the effect of one-level ACDF, comparing stand-alone cages and cage-with-plate fixation constructs with respect to clinical outcomes and radiologic changes. Patients and Methods: a total of 20 patients who underwent one-level for cervical disc disease and who completed 6 months of follow-up were included in this study. The patients were grouped into ACDF-Cage-only and ACDF-Cage-with-plate groups. The following parameters were assessed using radiographs: subsidence, adjacent disc space narrowing, clinical outcomes were assessed using the Odom's criteria. Results: in the comparison of one-level ACDF-cage-only and ACDF-cage-with-plate groups, at the 3-and 6-months follow-up: Regarding the functional outcome in the plate group 6 (60%) patients had excellent outcome, 2 (20%) patients had good outcome, 1 (10%) had satisfactory and 1 (10%) had poor outcome, while in the cage group 7 (70%) patients had excellent outcome, 110%) had good outcome, 1 (10%) had satisfactory and 1 (10%) had poor outcome. Conclusion: our results showed that for single-level cases, plate fixation had no additional benefit versus cage-only, although the cage-with-plate fixation group had a lower incidence of cage sinking than did the cage-only group. We conclude that physicians should be aware of these possible advantages and disadvantages associated with using cervical plates in one-level ACDF.

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.

PMD20 - COMPARATIVE STUDY OF SPINE ANTERIOR LUMBAR INTERBODY FUSION DEVICES

Patients may undergo anterior lumbar interbody fusion (ALIF) for treatment of degenerative disc disease, which can include the use of standalone cage devices to promote fusion across the disk space. During ALIFs with standalone devices, the surgeon may choose to additionally perform posterior fixation. To understand surgeon preferences during ALIF procedures, this study compared the rate of patients receiving fixation concurrent with ALIF of standalone cages. Patients who underwent ALIF of 2-3 vertebrae were identified in the Premier Healthcare Database using ICD-9/10 codes, 2010-2016. The cohort was categorized by cage: SYNFIX® LR System (DePuy Synthes, Raynham, MA) versus a group of comparator cages (non-SYNFIX). Patient, provider, hospital characteristics were collected. Patient outcomes evaluated were percent of fixation concurrent with ALIF, hospital costs, and operation room time (ORT). Logistic regression and generalized estimating equations were used to adjust outcomes. Of the 2,238 patients identified, 51.2% received SYNFIX® LR. Patients with SYNFIX® LR were younger (mean (SD), 47.9 (13.1) vs. 50.6 (12.1)), and more often male 47.1% vs. 43.7%; rates of diabetes (10.4% vs. 11.5%) and hypertension (37.3% vs. 42.0%), SYNFIX® LR vs. non-SYNFIX, were comparable. Procedures with SYNFIX® LR occurred more often at teaching hospitals (50.0% vs. 20.2%), but a similar frequency in urban hospitals (89.2% vs. 95.0%). SYNFIX® LR had a statistically significant lower odds of fixation, odds ratio, 0.75 (95% Confidence Interval (CI) 0.567, 0.996; p-value = 0.047). Overall procedure costs and ORT differences were not statistically significant, but mean values were lower for SYNFIX® LR: $31,839 (95% CI: $28,999-$34,957) vs. $33,694 ($30,565-$37,143); ORT 165.7 (157.9-173.9) vs. 176.6 (168.8-184.9) minutes. In patients treated with SYNFIX® LR vs. Non-SYNFIX, there was a statistically significant 25% reduction in fixation at the time of ALIF, with lower trends of overall procedure costs and ORT that were not statistically significant.

Anchored Spacers Versus Standalone Cages in Two Levels Anterior Cervical Discectomy for Treatment of Degenerative Cervical Disc Disease; A Comparative Study

Background Data: Anterior cervical discectomy and fusion (ACDF) has been standard procedure in treatment of degenerative cervical disc disease. In order to reduce risks associated with traditional methods of anterior cervical discectomy with fusion a new zero profile cage with screws has been introduced and widely used.Purpose: To compare the clinical and radiological outcomes of two levels ACDF using stand-alone peek cage and zero profile anchored cage with screws.Study Design: Two groups of patients were enrolled in this study; Group A involving 30 consecutive patients that underwent two levels ACDF using standalone peek cages, and Group B including 30 patients that underwent two levels ACDF with zero-profile anchored cage with screws.Patients and Methods: Both surgical groups were assessed clinically involving neck and arm pain Visual Analogue Score (VAS), neck disability index and Nurick score. Radiological evaluation involved the changes in vertebral heights (VH), both segmental (Cobb-s) and global (Cobb-c) Cobb angle and fusion rates via plain X-ray cervical spine that was done pre-operative, immediate post-operative and at 24 months post-operative.Results: The neck disability index and the Nurick score together with both VAS for neck and arm pain were significantly improved after surgery with no statistical difference between both groups. All patients in both groups showed satisfactory fusion rates except two patients in Group A. Both groups showed early marked increase in the VH followed later by cage subsidence that was significantly higher in Group A patients. In both groups; Cobb-c, and Cobb-s angles were significantly increased in the immediate postoperative compared to the preoperative measures. Terminal measures for both Cobb-c and Cobb-s, at 24 months follow up images, in both groups worsened but to a statistically significant lesser extent in Group B compared to Group A.Conclusion: The zero-profile anchored cage with screws compared to stand-alone peek cage was effective treatment for cervical disc disorders in two levels cervical discectomy and fusion and their results showed better result regarding the incidence of cage subsidence and maintaining cervical lordosis. (2018ESJ169)

A UK-based pilot study of current surgical practice and implant preferences in lumbar fusion surgery.

Lumbar fusion surgery is an established procedure for the treatment of low back pain. Despite the wide set of alternative fusion techniques and existing devices, uniform guidelines are not available yet and common surgical trends are scarcely investigated.The purpose of this UK-based study was to provide a descriptive portrait of current surgeons' practice and implant preferences in lumbar fusion surgery.A UK-based in-person survey was designed for this study and submitted to a group of consultant spinal surgeons (n = 32). Fifteeen queries were addressed based on different aspects of surgeons' practice: lumbar fusion techniques, implant preferences, and bone grafting procedures. Answers were analyzed by means of descriptive statistics.Thirty-two consultant spinal surgeons completed the survey. There was clear consistency on the relevance of a patient-centered management (82.3%), along with a considerable variability of practice on the preferred fusion approach. Fixation surgery was found to be largely adopted (96.0%) and favored over stand-alone cages. With regards to the materials, titanium cages were the most used (54.3%). The geometry of the implants influenced the choice of lumbar cages (81.3%). Specifically, parallel-shape cages were mostly avoided (89.2%) and hyperlordotic cages were preferred at the lower lumbar levels. However, there was no design for lumbar cages which was consistently favored. Autograft bone graft surgeries were the most common (60.0%). Amongst the synthetic options, hydroxyapatite-based bone graft substitutes (76.7%) in injectable paste form (80.8%) were preferred.Current lumbar fusion practice is variable and patient-oriented. Findings from this study highlight the need for large-scale investigative surveys and clinical studies aimed to set specific guidelines for certain pathologies or patient categories.

Comparison of Anterior Cervical Discectomy and Fusion With a Stand-Alone Interbody Cage Versus a Conventional Cage-Plate Technique: A Systematic Review and Meta-Analysis.

Study Design:Systematic review and meta-analysis.Objective:Compare the clinical and radiographic outcomes of anterior cervical discectomy and fusion (ACDF) with a stand-alone interbody cage versus a conventional cage and anterior cervical plate technique.Methods:A systematic Medline search was conducted using PubMed, EMBASE, and Cochrane Library Database of Systematic Reviews. Search terms included “anterior cervical discectomy and fusion,” “cage,” and “bone plates,” or variations thereof. Only studies involving a direct comparison of ACDF with a stand-alone cage versus a cage and plate were included. From the selected studies, we extracted data on patient demographics, comorbidities, surgical risk factors, and pre- and postoperative radiographic findings. A meta-analysis was performed on all outcome measures. The quality of each study was assessed using the Downs and Black checklist.Results:Nineteen studies met the inclusion and exclusion criteria. Patients who underwent ACDF with a cage-only technique had significantly lower rates of postoperative dysphagia and adjacent segment disease compared with patients who underwent ACDF with a cage-plate technique. However, patients who underwent ACDF with a cage-plate technique had better radiographic outcomes with significantly less subsidence and better restoration of cervical lordosis. There were no other significant differences in outcomes or postoperative complications.Conclusions:ACDF with a cage-only technique appears to have better clinical outcomes than the cage-plate technique, despite radiographic findings of increased rates of subsidence and less restoration of cervical lordosis. Future randomized controlled trials with longer term follow-up are needed to confirm the findings of this meta-analysis.