Two-level ACDF with a zero-profile stand-alone spacer compared to conventional plating: a prospective randomized single-center study

A retrospective comparative analysis of anterior cervical discectomy and fusion using stand-alone titanium cage versus cage and plate fixation in two-level cervical disc herniation

BACKGROUND

This study aims to compare the outcomes of two-level anterior cervical discectomy and fusion (ACDF) procedures using stand-alone cages versus cage and plate fixation in patients diagnosed with cervical disc herniation (CDH).

MATERIALS AND METHODS

This retrospective analysis included 60 patients who underwent two-level ACDF procedures. Patients were divided into two groups: one treated with stand-alone cages and the other with cage and plate fixation. Data on surgical duration, blood loss, fusion stability, and complication rates were collected. Clinical outcomes, including neck pain and functional status, were assessed using standard scoring systems.

RESULTS

Plate fixation provided superior fusion stability but was associated with longer surgery durations, higher intraoperative blood loss, and increased complication rates. Stand-alone cages reduced intraoperative trauma but demonstrated higher subsidence rates and prolonged fusion times. Both techniques resulted in significant improvements in neck pain and disability scores.

DISCUSSION

While both approaches are effective for managing cervical disc herniation, each has distinct advantages and limitations. Surgical technique selection should be individualized, considering patient-specific anatomical factors, functional demands, and the risk-benefit profile of each approach.

A Comparative Analysis of the Clinical and Radiological Results of a Zero-Profile Device Versus Conventional Cage and Plate Following Single-Level Anterior Cervical Discectomy and Fusion

Background Conventional cage and plating (CCP) and stand-alone self-interlocking zero profile cage (ZPC) are the two devices used in anterior cervical discectomy and fusion (ACDF) for the treatment of cervical spondylosis refractory to medical treatment. The utilization of zero-profile implants in ACDF for the management of degenerative cervical spondylosis has gained popularity. Nevertheless, the available evidence regarding its effectiveness and safety remains insufficient. Objective To compare the clinical and radiological outcomes of CCP and ZPC for single-level ACDF. Methodology In this retrospective cohort study, the records of patients who underwent single-level ACDF with CCP and ZPC between December 2021 and December 2023 were recruited in December 2024. Patients with ossified posterior longitudinal ligament, history of previous cervical surgery, severe comorbidities, older than 70 years and patients who utilized the circumferential fusion approach in combination were excluded from the study. The means and frequencies of clinical and radiological outcomes were compared between two groups via Mann-Whitney test, Fisher's exact test, and Chi-square test of significance, where p<0.05 was considered significant. The six-month follow-up data were recorded for all the patients included in the study. Results Of the 53 included patients, CCP was utilized in 30 (56.6%) and ZPC in 23 (43.4%) patients. The mean age of study participants was 53.8±9.3 years, with 35 (66%) males and 18 (34%) females. The ZPC implant resulted in reduced blood loss (p=0.001). However, no statistically significant difference was observed in operation time and the incidence of postoperative transient dysphagia between the two groups (p=0.532, p=0.569, respectively). Additionally, the ZPC implant demonstrated a significantly lower occurrence of postoperative dysphagia at two weeks and six months postoperatively (p=0.015 and p=0.039 respectively) compared to the CCP implant. Conclusion The utilization of ZPC may lead to positive clinical and radiological outcomes and decrease the frequency of postoperative dysphagia in ACDF procedures involving a single level.

Does Two-level Hybrid Surgery Promote Early Fusion Compared with Two-level Anterior Cervical Discectomy and Fusion?

BACKGROUND CONTEXT

Hybrid surgery (HS), which involves both anterior cervical discectomy and fusion (ACDF) and cervical disc replacement (ACDR), is increasingly used to treat multilevel cervical disc degenerative disease, yielding satisfactory clinical outcomes. Early fusion is critical after anterior cervical fusion surgeries, but there are no studies comparing the rate of early fusion of HS with that of ACDF.

PURPOSE

The purpose of this study was to compare the rate of early fusion (3-6 months postoperatively) of two-level HS with that of two-level ACDF surgery.

STUDY DESIGN

The fusion statuses of consecutive patients who underwent two-level ACDF were compared with those of consecutive patients who underwent HS, which involves both ACDF and ACDR.

PATIENT SAMPLE

The study included 860 patients who underwent two-level ACDF or HS for CDDD. After the patients who did not meet the study criteria were excluded, 376 patients were included (165 males, 211 females).

OUTCOME MEASURES

Radiographic measures included fusion rate of the ACDF level. Self-report measures included visual analog scale (VAS) neck, VAS arm, neck disability index (NDI), satisfaction with the surgery and other symptoms reported by patients during the follow-ups.

METHODS

Eight hundred sixty patients who underwent two-level ACDF or HS for cervical disc degenerative disease between January 2015 and January 2023 at our hospital were screened. After excluding the patients who did not meet the study criteria, 376 patients were included (165 males, 211 females). The patients who underwent dual-segment ACDF were categorized into the ACDF-ACDF (FF) group (n=205), while those who underwent dual-segment HS were divided into the ACDF-ACDR (FR) group (n=82) and the ACDR-ACDF (RF) group (n=89) on the basis of the relative positions of the segments selected for ACDF and ACDR. The fusion rates of the segments subjected to ACDF and the clinical outcomes, including the neck VAS score, arm VAS score, NDI score, and other complications, were compared among the three groups at 3 months, 6 months, and 1 year postoperatively. Fusion was defined as the formation of a continuous bone bridge in the target fusion area, as observed on three-dimensional computed tomography (CT) images.

RESULTS

The average age of the patients in the FF group was higher than that of the patients in the FR and RF groups (p<0.001). At 3 months postoperatively, the fusion rate was 70.7% (58/82) in the FR group, 39.5% (162/410) in the FF group, and 42.7% (78/89)in the RF group (P<0.001). At 6 months postoperatively, the fusion rate was 74.6% (306/410) in the FF group, 91.5% (75/82) in the FR group, and 87.6% (78/89) in the RF group (P<0.001). At 1 year postoperatively, the fusion rate was 91.9% (377/410) in the FF group, 98.8% (81/82) in the FR group, and 100% (89/89) in the RF group (P=0.002). At 3 months postoperatively, the fusion rate was higher in the FR group than in the FF group (70.7% vs. 45.4%) (P<0.001). At 6 months postoperatively, the fusion rate of the distal segment was higher in the RF group than in the FF group (87.6% vs. 66.3%). In the FF group, the fusion rate in the proximal segment was higher than that in the distal segment at 3, 6, and 12 months postoperatively. One year after surgery, 15 segments-3 proximal and 12 distal-in the FF group developed pseudoarthrosis. Compared with the other two groups, the FR group had lower neck VAS scores at 3 months postoperatively and a lower rate of dizziness complaints during the 1-year follow-up period. There were no statistically significant differences in the remaining clinical outcomes.

CONCLUSIONS

The early fusion rate after two-level HS was higher than that after two-level ACDF. The early fusion rate of two-level HS was higher in the FR group than in the RF group. For two-level ACDF, the early fusion rate was higher in the proximal segment than in the distal segment. Additional biomechanical studies are needed to explore the biomechanical differences in fusion levels between HS and multilevel ACDF.

Does the Angulation of the Screws in the Zero-P Implant Affect the Clinical and Radiological Outcomes of Patients?

OBJECTIVE

When implanting the Zero-P device, the screws of Zero-P form a bone wedge with a 40 ± 5° cranial and caudal angle (CCA). However, no study has been performed in the optimal CCA of the Zero-P implant. To investigate whether the cranial/caudal angles (CCA) of the screws affect the clinical and radiological outcomes in patients undergoing ACDF with the Zero-P implant.

METHODS

From January 2016 to December 2023, we retrospectively analyzed 186 patients who underwent 1-level ACDF with the Zero-P device. The patients were divided into four groups: group A (cranial angle ≤40°, caudal angle ≤40°); group B (cranial angle ≤40°, caudal angle >40°); group C (cranial angle >40°, caudal angle ≤40°); and group D (cranial angle >40°, caudal angle >40°). The clinical outcomes, including Japanese Orthopaedic Association (JOA), neck disability index (NDI), and visual analogue scale (VAS) scores, the radiological parameters, including cervical lordosis (CL), cervical lordosis of operated segments (OPCL), intervertebral space height (ISH) and fusion rate (FR), and the complications, were evaluated and compared. Parametric tests, non-parametric tests, and chi-square tests were conducted to analyze the data.

RESULTS

The OPCL of group A was significantly less than that of the other groups at the final follow-up (p < 0.05). The ISH of group D was significantly less than that of group A at the final follow-up (p < 0.05). The subsidence rate of group A was significantly less than that of group D at the final follow-up (p < 0.05). At the final follow-up, the upper adjacent-level degeneration (ASD) of group D was significantly less severe than that of groups A and B (p < 0.05). The clinical outcomes do not differ among groups (p > 0.05).

CONCLUSION

A larger CCA of the screws (cranial angle >40°, caudal angle >40°) was better for maintaining OPCL and reducing the incidence of ASD. A smaller CCA of the screws (cranial angle ≤40°, caudal angle ≤40°) was better for maintaining ISH and reducing the rate of subsidence.

Clinical and Radiological Outcomes of Anchored Stand-Alone Cage Compared to Conventional Plating in Multilevel Anterior Cervical Discectomy and Fusion: A Systematic Review

Multilevel cervical degenerative disc disease (cDDD) is typically treated through anterior cervical discectomy and fusion (ACDF). Traditionally, the plate-cage construct (PCC) has been utilized, though alternatives such as the locking stand-alone cage (LSC) have become popular. This systematic review aims to assess differences in clinical and radiological outcomes between LSC and PCC methods in the ACDF management of multilevel cDDD by aggregating existing literature. A comprehensive search of five electronic databases (PubMed, Medline, Ovid, Embase, and Cochrane) was conducted from 2015 to 2022 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The comparative studies were assessed using the Methodological Index for Non-randomized Studies (MINORS) criteria and the two randomized controlled trials (RCTs) were assessed using the Jadad scale for RCT. Eight studies met the inclusion criteria, comprising a total cohort of 516 contiguous multilevel cDDD cases treated via ACDF, with 254 (49%) managed with PCC and 262 (51%) treated with LSC. The comparative outcomes assessed included the rate of subsidence and the rate of postoperative dysphagia. The LSC approach exhibited a higher incidence of cage subsidence compared to PCC. Conversely, dysphagia was observed more frequently in patients receiving PCC compared to those treated with LSC. Clinical outcomes and functional scores did not reveal significant differences. Clinical measures such as the Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), visual analog scale (VAS), and Odom's and Robinson's criteria revealed no significant differences between treatment groups in seven of the studies. However, one of the included studies reported a statistically significant improvement in the LSC group for VAS and Odom's criteria. The incidence of cage subsidence in ACDF surgery varies depending on the cage type employed. Among the reviewed studies, the LSC group exhibited a higher incidence of subsidence compared to the PCC group, with the exception of one study that reported no cases of subsidence. Variability in subsidence rates across studies may be attributed to differences in surgical techniques, patient demographics, and follow-up periods. Further research is necessary to investigate associated risk factors and to develop strategies aimed at minimizing this complication in ACDF procedures.

Comparison of Interbody Fusion Strategies in Anterior Cervical Discectomy and Fusion: A Network Meta-Analysis and Systematic Review

OBJECTIVE

The optimal choice for fusion strategy in Anterior Cervical Discectomy and Fusion (ACDF) remains an unresolved issue. This study aims to perform a network meta-analysis and systematic review of fusion rate and complication rate of various fusion strategies used in ACDF.

METHODS

This study followed Prisma guidelines, and we searched PubMed, Embase, Cochrane Library, and Web of Science from inception to November 11, 2022, for Randomized Controlled trials comparing the efficacy and safety of fusion modalities in ACDF. The primary outcome was the fusion rate and complication rate. The PROSPERO number is CRD42022374440.

RESULTS

This meta-analysis identified 26 Randomized Controlled trial studies with 1789 patients across 15 fusion methods. The cage with autograft + plating showed the highest fusion rate, surpassing other methods like iliac crest bone graft (ICBG) and artificial bone graft (AFG). The stand-alone cage with autograft (SATG) had the second highest fusion rate. Regarding complication rate, the cage with AFG (CAFG) had the highest rate, more than other methods. The ICBG had a higher complication rate compared to ICBG + P, AFG, stand-alone cage with artificial bone graft, SATG, and CALG. The SATG performed well in both fusion and complication rate.

CONCLUSIONS

In this study, we conducted the first network meta-analysis to compare the efficacy and safety of various fusion methods in ACDF. Our findings suggest that SATG, with superior performance in fusion rate and complication rate, may be the optimal choice for ACDF. However, the results should be interpreted cautiously until additional research provides further evidence.

Assessing Surgical Outcomes for Cage Plate System versus Stand-Alone Cage in Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is a common surgical procedure for addressing cervical spine conditions. It involves the utilization of either cage plate system (CPS) or stand-alone cage (SC). The objective of our study is to compare perioperative complications, patient-reported clinical outcomes measures, and radiographic outcomes of SC versus CPS in ACDF.

METHODS

We carried out a literature search in PubMed, Embase, Cochrane library, Web of science, Medline, and Google Scholar. All studies comparing the outcomes between CPS versus SC in ACDF were included.

RESULTS

Forty-one studies, 33 observational and 8 randomized clinical trials met the inclusion criteria. We found that both devices demonstrated comparable effectiveness in monosegmental ACDF with respect to Japanese Orthopedic Association Score, Neck Disability Index score, visual analog score, and fusion rates. CPS demonstrated superior performance in maintaining disc height, cervical lordosis, and exhibited lower incidence rates of cage subsidence. SC showed significant advantages over CPS in terms of shorter surgical duration, less intraoperative bleeding, shorter duration of hospitalization, as well as lower incidence rates of early postoperative dysphagia and adjacent segment disease.

CONCLUSIONS

Most of the included studies had monosegmented fusion, and there wasn't enough data to set recommendations for the multisegmented fusions. Larger studies with longer follow-up are necessary to draw more definitive conclusions to provide evidence for clinicians to make clinical decisions.

The efficacy of anchored stand-alone spacers in comparison to conventional cage and plate in anterior cervical discectomy and fusion surgery: A meta-analysis of randomised controlled trials for clinical and radiological outcomes

Introduction

Anterior cervical discectomy and fusion (ACDF) is commonly performed with cage and plate constructs to stabilise diseased or injured cervical segments. Despite it being a commonly performed procedure, there are notable rates of associated morbidity reported in the literature. Stand-alone spacers represent a novel form of instrumentation to conventional cage and plate constructs.

Research question

Do stand-alone spacers have improved operative characteristics and postoperative outcomes in ACDF cohorts when compared to cage and plate constructs?

Methods

A systematic review and meta-analysis was conducted of PubMed/Medline, Embase and Google Scholar databases per the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes guidelines. Studies of interest included cage and plate instrumentation versus anchored stand-alone spacers for patients undergoing ACDF. Pre- and post-operative clinical and radiological outcomes were collated and compared for significance between cohorts.

Results

10 RCTs were identified and included with 779 patients total. Mean age of the entire cohort was 50.1 years. 62% (483/779) of the cohort were male. 384 patients underwent ACDF with stand-alone cage, while 395 had ACDF with conventional cage and plate. Stand-alone spacers significantly outperformed conventional instrumentation in terms of estimated blood loss (p < 0.01), total postoperative complications (p < 0.01), dysphagia rates (p = 0.04) and adjacent segment disease (p = 0.04). Non-inferiority was evident in both patient reported outcome measures and radiological outcomes.

Conclusion

This meta-analysis highlights the efficacy of stand-alone spacers for the management of primarily cervical spondylitic disease for both single-level and multi-level pathology, and thus presents an attractive alternative to conventional instrumentation for patients undergoing ACDF surgery.

Clinical and Radiographic Outcomes for Patients with Cervical Adjacent Segment Disease Treated with Anterior Cervical Discectomy and Fusion with Integrated Interbody Spacers

INTRODUCTION

Anterior cervical discectomy and fusion (ACDF) is among the most common spine procedures. Adjacent segment disease (ASD), characterized by degenerative disease at an adjacent spinal level to a prior fusion, is a well-recognized and significant sequela following ACDF. Adjacent segment ACDF may be considered after the failure of non-surgical options for patients with symptomatic ASD. This study aimed to assess the incidence of dysphagia and other complications as well as radiographic outcomes in adult patients who have undergone ACDF with an integrated interbody spacer device for symptomatic ASD.

METHODS

This was a retrospective review of patients who underwent ACDF for symptomatic ASD with commercially available integrated interbody spacers by three spine surgeons at an academic institution from March 2018 to April 2022. Demographic, radiographic, and postoperative data were collected, including dysphagia, device-related complications, and the need for revision surgery.

RESULTS

There were 48 patients (26 male, 22 female) who met inclusion criteria (mean age 59.7 years, mean body mass index 19.5 kg/m2) who underwent ACDF for symptomatic ASD (1one-level, n = 44; 2-level, n = 4). Overall, 12 patients (25%) experienced dysphagia postoperatively before the first follow-up appointment. Nine of 44 (20.4%) of 1-level ACDF patients experienced dysphagia, and 3 of 4 (75%) of 2-level ACDF patients experienced dysphagia. Three patients had severe dysphagia which prompted an otolaryngology referral. Two of those patients remained symptomatic at 6 weeks postoperatively. Of 43 patients with prior plate cage systems, none required hardware removal at the time of surgery. Preoperative global and segmental lordosis were 9.07° ± 8.36° (P = 0.22) and 3.58° ± 4.57° (P = 0.14), respectively. At 6 weeks postoperatively, global and segmental lordosis were 11.44° ± 9.06° (P = 0.54) and 5.11° ± 4.44° (P = 0.44), respectively. This constitutes a change of +2.37° and +1.53° in global and segmental lordosis, respectively. The mean anterior disc height change between preoperative and immediate postoperative time points was 6.3 ± 3.1 mm. Between the immediate postoperative and 6-week postoperative time points, the mean anterior disc height change was -1.5 ± 2.7 mm. Between the immediate postoperative and 3-month postoperative time points, the mean anterior disc height change was -3.7 ± 5.0 mm. The posterior disc height changes at the same time points were 2.5 ± 1.7 mm, -0.4 ± 1.8. and -0.5 ± 1.4 mm, respectively. This fusion rate was 50% and 70% at 6 months and 1 year post-surgery, respectively.

CONCLUSIONS

ACDF with integrated spacer is a viable alternative to traditional plate-cage systems for symptomatic ASD. An advantage over traditional plate-cage systems is that the removal of prior instrumentation is not needed in order to place implants. Based on a review of the literature, these standalone systems allowed for a shorter operative time and had less incidence of dysphagia than plate-cage systems for ASD after ACDF. The different standalone and plate-cage systems used in treating ASD after ACDF surgeries should be compared in prospective studies.

Evaluation of outcome measures for post-operative dysphagia after anterior cervical discectomy and fusion

PURPOSE

The goal is to conduct a review of the current literature to determine and evaluate the current classification metrics available for quantifying post-operative dysphagia.

METHODS

We surveyed the literature for the subjective and objective measures used to classify dysphagia, and further described and analyzed them in the context of post-operative dysphagia (PD) after anterior cervical spine surgery, with a focus on anterior cervical discectomy and fusion (ACDF). We searched PubMed from the years 2005-2021 using the terms "anterior cervical discectomy and fusion" and "dysphagia or postoperative dysphagia." We included papers that were meta-analyses, systemic reviews, prospective, or retrospective studies. Our selection was further consolidated via abstract and title screening. Ultimately, nineteen articles were included and had full-text reviews.

RESULTS

EAT-10 tool was shown to be more valid and reliable than the commonly used Bazaz grading system. HSS-DDI was found to have a high diagnostic accuracy in stratifying mild, moderate, and severe PD. A shortened 16-item version of the original 44-item SWAL-QOL was found to be statistically and clinically significant. When compared to PROMs, objective tests more accurately diagnose PD.

CONCLUSION

We found that the most valuable subjective tests were the EAT-10 and HSS-DI because they are quick, sensitive, and correlated strongly with the well-established measurements of PD. The MBS and FEES provided accurate measurements of the severity of PD, but they required more time and equipment than the surveys. In some patient populations, such as those with pre-surgical dysphagia, objective testing should always be done.

Follow-up of a new titanium cervical plate for fusion of the cervical spine

Cervical plates are in use since the 1990ies for anterior cervical discectomy and fusion (ACDF). The latest step in development was a dynamic plate that allows sliding of the screws facilitating the natural settling of the bone after surgery. We investigated the clinical and radiological results of such a dynamic plate in a patient cohort that underwent single or multi-level ACDF for various cervical degenerative indications, including revision cases, from 2014 to 2019. Clinical and radiological outcome were assessed in 60 eligible patients after a mean of 2.9 years. The assessed neck disability index (NDI), and the visual analogue scale (VAS) of neck and arm pain show comparable results to the literature of ACDF, and specifically other plate designs. Forty-eight Adverse and Serious Adverse Events do not show a link to the product used. Clinical and radiological outcomes of ACDF with dynamic, third generation cervical plates show comparable results to the literature. Careful reporting of all Adverse Events revealed a variety of concomitant diseases, but could not be correlated to the implant used.

Biomechanical evaluation of a novel individualized zero-profile cage for anterior cervical discectomy and fusion: a finite element analysis

Introduction: Anterior cervical discectomy and fusion (ACDF) is a standard procedure for treating symptomatic cervical degenerative disease. The cage and plate constructs (CPCs) are widely employed in ACDF to maintain spinal stability and to provide immediate support. However, several instrument-related complications such as dysphagia, cage subsidence, and adjacent segment degeneration have been reported in the previous literature. This study aimed to design a novel individualized zero-profile (NIZP) cage and evaluate its potential to enhance the biomechanical performance between the instrument and the cervical spine. Methods: The intact finite element models of C3-C7 were constructed and validated. A NIZP cage was designed based on the anatomical parameters of the subject's C5/6. The ACDF procedure was simulated and the CPCs and NIZP cage were implanted separately. The range of motion (ROM), intradiscal pressure (IDP), and peak von Mises stresses of annulus fibrosus were compared between the two surgical models after ACDF under four motion conditions. Additionally, the biomechanical performance of the CPCs and NIZP cage were evaluated. Results: Compared with the intact model, the ROM of the surgical segment was significantly decreased for both surgical models under four motion conditions. Additionally, there was an increase in IDP and peak von Mises stress of annulus fibrosus in the adjacent segment. The NIZP cage had a more subtle impact on postoperative IDP and peak von Mises stress of annulus fibrosus in adjacent segments compared to CPCs. Meanwhile, the peak von Mises stresses of the NIZP cage were reduced by 90.0-120.0 MPa, and the average von Mises stresses were reduced by 12.61-17.56 MPa under different motion conditions. Regarding the fixation screws, the peak von Mises stresses in the screws of the NIZP cage increased by 10.0-40.0 MPa and the average von Mises stresses increased by 2.37-10.10 MPa. Conclusion: The NIZP cage could effectively reconstruct spinal stability in ACDF procedure by finite element study. Compared with the CPCs, the NIZP cage had better biomechanical performance, with a lower stress distribution on the cage and a more moderate effect on the adjacent segmental discs. Therefore, the NIZP cage could prevent postoperative dysphagia as well as decrease the risk of subsidence and adjacent disc degeneration following ACDF. In addition, this study could serve as a valuable reference for the development of personalized instruments.

Zero-profile anchored spacer versus conventional plate-cage construct in bilevel anterior cervical discectomy and fusion: a systematic review and meta-analysis

BACKGROUND

Zero-profile anchored spacers (ZAS) and plate-cage constructs (PCC) are currently employed when performing anterior cervical discectomy and fusion (ACDF). Nevertheless, the efficacy and safety of both devices in bilevel ACDF remain controversial. The goal of our meta-analysis is to assess the overall long-term efficacy and security among ZAS and PCC in bilevel ACDF.

METHODS

A search of four electronic databases was conducted to identify researches that compared ZAS with PCC for bilevel ACDF. Stata MP 17.0 software was used for this meta-analysis.

RESULTS

Nine researches with a total of 580 patients were involved. In comparison to PCC, ZAS significantly reduced intraoperative bleeding and postoperative dysphagia rates. No significant differences were found concerning operation time, JOA score, NDI score, cervical Cobb angle, fusion rates, the incidence of adjacent segmental degeneration (ASD) and implant sinking rates at last follow-up.

CONCLUSION

Compared to PCC, ZAS achieved similar efficacy and security in bilevel ACDF with respect to operative time, JOA score, NDI score, cervical Cobb angle, fusion rates, implant sinking rates and ASD rates at final follow-up. It is worth noting that ZAS offered considerable benefits over conventional PCC for the reduction of intraoperative bleeding and postoperative dysphagia. Therefore, for patients requiring bilevel ACDF, ZAS seems superior to PCC. Given the limitations of our study, larger prospective randomised controlled trials are needed to establish reliable proof to consolidate our conclusions.

A Retrospective Evaluation and Review of Radiographic Outcomes for Anterior Cervical Discectomy and Fusion (ACDF) Procedures: Northern Ireland's Experience

Introduction Anterior Cervical Discectomy and Fusion (ACDF) is the gold standard treatment for symptomatic cervical spondylosis refractory to analgesic medical management. Currently, there are numerous approaches and devices used; however, there is no single implant that is preferred for this procedure. The aim of this study is to evaluate the radiological outcomes of ACDF procedures performed in the regional spinal surgery centre in Northern Ireland. The results of this study will aid surgical decision-making, specifically with regard to the choice of implant. The implants that will be assessed in this study are the stand-alone polyetheretherketone (PEEK) cage (Cage) and the Zero-profile augmented screw implant (Z-P). Methods A total of 420 ACDF cases were reviewed retrospectively. Following exclusion and inclusion criteria, 233 cases were reviewed. In the Z-P group, there were 117 patients, with 116 in the Cage group. Radiographic assessment was carried out at the pre-operative stage, day one post-operation, and follow-up (> three months). Measured parameters included segmental disc height, segmental Cobb angle, and spondylolisthesis displacement distance. Results Patient characteristic features showed no significant difference between the two groups (p>0.05) and no significant difference in mean follow-up time (p=0.146). The Z-P implant was superior in increasing and maintaining disc height post-operatively (+0.4±0.94mm, 5.20±0.66mm) compared to the Cage (+0.1±1.00mm, 4.40±0.95mm) (p<0.001). Z-P was also more successful in restoring and maintaining cervical lordosis in comparison to the Cage group, as it had a significantly smaller kyphosis incidence (0.85% vs. 34.5%) at follow-up (p<0.001). Conclusions Results of this study show a more advantageous outcome in the Zero-profile group as it restores and maintains both disc height and cervical lordosis; it is also more successful in treating spondylolisthesis. This study advocates cautious endorsement of the use of the Zero-profile implant in ACDF procedures for symptomatic cervical disc disease.

Clinical and imaging outcomes of self-locking stand-alone cages and anterior cage-with-plate in three-level anterior cervical discectomy and fusion: a retrospective comparative study

BACKGROUND

Anterior cervical discectomy and fusion has been considered standard management for cervical myelopathy and radiculopathy. However, the option of using self-locking stand-alone cages or cage-with-plate in three-level anterior cervical discectomy and fusion still remains controversial. The aim of this study was to evaluate the clinical and imaging outcomes of the two procedures in multilevel anterior cervical discectomy and fusion.

METHODS

Sixty-seven patients who underwent three-level anterior cervical discectomy and fusion were enrolled in this study, of which 31 patients underwent surgery using self-locking stand-alone cages (group cage) and 36 patients using cage-with-plate (group plate). For the evaluation of clinical outcomes, modified Japanese Orthopedic Association scores, visual analogue scale for neck pain, neck disability index, Odom's criteria and dysphagia status were measured. Imaging outcomes were evaluated by cervical sagittal angle, fusion segmental Cobb's angle, fusion segmental height, range of motion, cage subsidence rate, fusion rate and adjacent segment degeneration. Statistical analyses were performed using the SPSS software (version 19.0).

RESULTS

Both groups showed improvement in modified Japanese Orthopedic Association scores, visual analogue scale for neck pain and neck disability index, after surgery, and there was no significant difference between the groups. The occurrence rate of dysphagia is significantly lower in the group cage compared with the group plate (p < 0.05). The postoperative cervical sagittal angle, fusion segmental Cobb's angle, fusion segmental height and cage subsidence rate in the group plate were significantly superior to that in the group cage (p < 0.05). However, the rate of adjacent segment degeneration was significantly lower in the group cage compared with the group plate (p < 0.05). Both groups showed no significant difference in terms of fusion rate (p > 0.05).

CONCLUSIONS

The self-locking stand-alone cages are effective, reliable and safe in anterior cervical discectomy and fusion for the treatment of cervical myelopathy and radiculopathy. Self-locking stand-alone cages showed a significantly lower rate of dysphagia and adjacent segment degeneration, while anterior cervical cage-with-plate could provide stronger postoperative stability and maintain better cervical spine alignment.

Anterior cervical discectomy and fusion with zero-profile versus stand-alone cages for two-level cervical spondylosis: A retrospective cohort study

OBJECTIVE

To assess the mid-long-term clinical and radiological outcomes of zero-profile (ZP) compared with stand-alone (ST) cages for two-level anterior cervical discectomy and fusion (ACDF).

METHODS

We included 77 patients (39 women and 38 men) who underwent two-level ACDF between May 5, 2016, and May 5, 2020, and who were followed up for at least 1 year. The subjects were divided into the ST (n = 38) and ZP (n = 39) group. For the evaluation of functional status, Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), and Visual Analogue Scale (VAS) scores were used. Additionally, radiological outcomes and procedure complications were observed at final follow-up.

RESULTS

Both groups had excellent clinical outcomes at the final follow-up. There were no significant intergroup (ZP vs. ST) differences in the fusion rate (91.02% vs. 90.79%, P > 0.05) and postoperative dysphagia (15.4% vs. 2.6%, P = 0.108). However, the disc height at the final follow-up in the ZP group was higher than that in the ST group (6.86 ± 0.84 vs. 6.17 ± 1.03, P = 0.002). The ZP group accomplished a lower loss of cervical lordosis (18.46 ± 4.78 vs. 16.55 ± 4.36, P = 0.071), but without reaching statistical significance.

CONCLUSION

ACDF with either ZP or ST cages turns out to be a dependable strategy for two-level ACDF in terms of clinical results. However, compared with the ST, the ZP cage may achieve a significantly lower loss of disc height.

Clinical and radiological comparison of the zero-profile anchored cage and traditional cage-plate fixation in single-level anterior cervical discectomy and fusion

BACKGROUND

The aim of this study was to compare the clinical outcomes and radiographic parameters of the zero-profile anchored cage and traditional cage-plate fixation in single-level anterior cervical discectomy and fusion (ACDF).

METHODS

Between January 2016 and November 2018, a total of 68 patients with degenerative cervical spondylosis who underwent single-level ACDF were evaluated in this retrospective study. Thirty-five patients were treated with the zero-profile anchored cage (Zero-P group), and 33 patients were treated with the traditional cage-plate fixation (Cage group). The two groups were compared in reference to clinical outcomes and radiographic parameters.

RESULTS

The mean operation time in the Zero-P group was significantly shorter than that in the Cage group. The incidence of postoperative dysphagia in the Cage group was higher than that in the Zero-P group at 3 months and 12 months postoperatively. No bony spurs were found in the Zero-P group, whereas 5 patients in the Cage group developed bony spurs. There were no statistically significant differences between the two groups in the JOA scores, VAS scores, NDI scores, C2-7 Cobb angles, segmental Cobb angles, total interbody height or fusion rates at 3 months or 12 months postoperatively.

CONCLUSION

In this study, both the zero-profile anchored cage and traditional cage-plate fixation were demonstrated to be effective and safe strategies. Given the lower incidence of dysphagia and degenerative changes, zero-profile anchored cage is a good option.

A New Potential Complication in 2-Level Anterior Cervical Discectomy and Fusion with Zero-Profile Devices: Collapse of the Middle Cervical Vertebra

OBJECTIVE

The objective of this study was to describe a new potential complication, collapse in the middle cervical vertebra of consecutive 2-level anterior cervical discectomy and fusion (ACDF), and discuss its possible mechanism.

METHODS

Clinical and radiologic outcome data from 27 consecutive 2-level ACDF patients using zero-profile devices were collected at 1, 3, 6, and 12 months postoperatively, as well as the last follow-up. Dysphagia was assessed using the Bazaz score, and clinical outcomes were analyzed using the neck disability index and Japanese Orthopaedic Association score. Radiographic evaluation included measurements of the overall and surgical segment curvature, identification of collapse, and assessment of the ratio of anterior height and wedge of the upper, middle, and lower vertebrae in the surgical segment.

RESULTS

The application of zero-profile devices to treat consecutive 2-level cervical spondylosis mostly resulted in good midterm clinical outcomes. Surprisingly, as evidenced by the significantly decreased anterior height and wedge ratio of the middle cervical vertebra, collapse was noted immediately in the middle vertebra in 4 patients at 1 month (n = 3) and 3 months (n = 1). The collapse increased for no more than 6 months, and there was no deterioration of clinical and radiological outcomes at the last follow-up.

CONCLUSIONS

Collapse in the middle cervical vertebra of consecutive 2-level ACDF with the application of zero-profile devices can occur in the early postoperative period, which may be due to axial stress concentration and blood supply damage in the middle cervical vertebral body.

Comparison of outcomes between Zero-p implant and anterior cervical plate interbody fusion systems for anterior cervical decompression and fusion: a systematic review and meta-analysis of randomized controlled trials

Purpose

The clinical outcomes of using a zero-profile for anterior cervical decompression and fusion were evaluated by comparison with anterior cervical plates.

Methods

All of the comparative studies published in the PubMed, Cochrane Library, Medline, Web of Science, EBSOChost, and EMBASE databases as of 1 October 2021 were included. All outcomes were analysed using Review Manager 5.4.

Results

Seven randomized controlled studies were included with a total of 528 patients, and all studies were randomized controlled studies. The meta-analysis outcomes indicated that the use of zero-profile fixation for anterior cervical decompression and fusion was better than anterior cervical plate fixation regarding the incidence of postoperative dysphagia (P < 0.05), adjacent-level ossification (P < 0.05), and operational time (P < 0.05). However, there were no statistically significant differences in intraoperative blood loss, Visual Analogue Scale, Neck Disability Index, or Japanese Orthopaedic Association scale (all P > 0.05) between the zero-profile and anterior cervical plate groups.

Conclusions

The systematic review and meta-analysis indicated that zero-profile and anterior cervical plates could result in good postoperative outcomes in anterior cervical decompression and fusion. No significant differences were found in intraoperative blood loss, Visual Analogue Scale, Neck Disability Index, or Japanese Orthopaedic Association scale. However, the zero-profile is superior to the anterior cervical plate in the following measures: incidence of postoperative dysphagia, adjacent-level ossification, and operational time.

PROSPERO registration CRD42021278214.

Anterior Cervical Discectomy and Fusion Using Zero-P System for Treatment of Cervical Spondylosis: A Meta-Analysis

Objective

The current study aimed to explore the efficacy of Zero profile intervertebral fusion system (Zero-P) and traditional anterior plate cage system (PC) in the treatment of cervical spondylotic myelopathy (CSM). Further, the present study evaluated effects of the treatments on medical security, height of intervertebral disc, adjacent-level ossification development (ALOD), and adjacent segmentation disease (ASD) through a systematic retrospective analysis.

Methods

Studies on Zero-P system and traditional anterior plate cage system for ACDF in the treatment of CSM were searched in PubMed, Web of Science, Ovid, Embase, and Cochrane Library databases. Two independent researchers screened articles, extracted data, and evaluated the quality of the articles based on the inclusion and exclusion criteria of the current study. RevMan5.3 software was used for meta-analysis following the guidelines of Cochrane collaboration network. Cervical curvature, interbody fusion rate, preoperative and postoperative disc height index (DHI), fusion cage sinking rate, postoperative dysphagia, ASD, ALOD, and loosening of screw were compared between the two groups.

Results

A total of 17 literatures were included in the present study, including 6 randomized controlled trials and 11 observational studies. The studies comprised a total of 1204 patients with CSM, including 605 patients in the Zero-P system group (Zero-P group) and 599 patients in the traditional animal plate cage group (PC group). Results of this meta-analysis showed that postoperative dysphagia [OR = 0.40, CI (0.28, 95% 0.58), P < 0.00001], ALOD [OR = 0.09, CI (0.02, 95% 0.39), P = 0.001], ASD [OR = 0.42, CI (0.20, 95% 0.86), P = 0.02], and screw loosening [OR = 0.20, CI (0.08, 95% 0.52), P = 0.0009] of the Zero-P group were significantly lower compared with the PC group. On the other hand, preoperative cervical curvature [WMD = −0.23, CI (−1.38, 95% 0.92), P = 0.69], postoperative cervical curvature [WMD = −0.38, CI (−1.77, 95% 1.01), P = 0.59], cage sinking rate [OR = 1.41, CI [0.52, 95% 3.82], P = 0.50], intervertebral fusion rate [OR = 0.76, CI (0.27, 95% 2.48), P = 0.38], preoperative DHI [WMD = −0.04, CI (−0.14, 95% 0.22), P = 0.65], and postoperative DHI [WMD = 0.06, CI (−0.22, 95% 0.34), P = 0.675] were not significantly different between the two groups.

Conclusion

It was evident that the Zero-P system used in ACDF is superior compared with the traditional anterior plate cage system in postoperative dysphagia, avoiding ALOD, ASD, and screw loosening.

Is the fusion order of the cranial and caudal levels different in two-level anterior cervical discectomy and fusion for cervical spondylopathy? A retrospective study

STUDY DESIGN

Retrospective study.

OBJECTIVE

This study aimed to compare the fusion order between the cranial and caudal levels in two-level anterior cervical discectomy and fusion (ACDF) with a zero-profile device in the treatment of cervical spondylopathy. Fusion is the standard used to judge the success of ACDF. However, the fusion order in two-level ACDF remains uncertain. The mechanical environment of different levels is different, which may affect the fusion rate or fusion order.

METHODS

From 2014 to January 2019, data of consecutive patients with two-level cervical disk degenerative disease who underwent ACDF were retrospectively reviewed. Radiological assessments were based on the range of motion of the fusion level, segment slope, and disk height, and complications were assessed. Data were analyzed using the paired t, Mann-Whitney U, χ2, Fisher exact, and rank-sum tests and logistic regression analysis.

RESULTS

In total, 118 patients were ultimately enrolled for analysis in the study. The respective fusion rates of the cranial and caudal levels were 26.27% and 10.17% (p < 0.05) at 3 months, 58.47% and 42.37% (p < 0.05) at 6 months, 86.44% and 82.20% (1 0.05) at 1 year, and 92.37% and 89.83% (p > 0.05) at the last follow-up. Multivariate logistic regression analysis indicated that the preoperative segmental slope and cranial level were independent risk factors for non-fusion. The adjacent segment degeneration (ASD) and subsidence rates were comparable between the two levels.

CONCLUSION

The caudal level had a slower fusion process than the cranial level. A higher preoperative segment slope was a risk factor for fusion. However, the subsidence and ASD rate were comparable between the caudal and cranial levels in the two-level ACDF.