Application of Zero-profile Spacer in the Treatment of Three-level Cervical Spondylotic Myelopathy: 5-year Follow-up Results

Does Focal Kyphotic Deformity at Non-responsible Levels Affect the Outcomes of Anterior Cervical Decompression and Fusion?

OBJECTIVE

Focal cervical kyphotic deformity (FCK) without neurologic compression is not uncommon in patients with cervical spondylotic myelopathy (CSM) who underwent anterior cervical decompression and fusion (ACDF) surgery. It remains unclear whether FCK at non-responsible levels needs to be treated simultaneously. This study aims to investigate whether FCK at non-responsible levels is the prognostic factor for CSM and elucidate the surgical indication for FCK.

METHODS

Patients with CSM who underwent ACDF between January 2016 and April 2021 were included. Patients were divided into two groups according to the presence of FCK and two classifications according to global cervical sagittal alignment. Clinical outcomes were compared using Japanese Orthopaedic Association (JOA) scores and recovery rate (RR) of neurologic function. Univariate and multivariate analysis based on RR assessed the relationship between various possible prognostic factors and clinical outcomes. The receiver operating characteristic curve (ROC) was used to determine the optimal cutoff value of the focal Cobb angle to predict poor clinical outcomes.

RESULTS

A total of 94 patients were included, 41 with FCK and 53 without. Overall, the RR of neurologic function was significantly lower in the FCK than in the non-FCK group. Further analysis showed that the RR difference between the two groups was only observed in hypo-lordosis classification (kyphotic and sigmoid alignment), but not in the lordosis classification. Multivariate analysis showed that the preoperative focal Cobb angle in the FCK level (OR = 0.42; 95% CI = 0.18-0.97) was independently associated with clinical outcomes in the hypo-lordosis classification. The optimal cutoff point of the preoperative focal kyphotic Cobb angle was calculated at 4.05°.

CONCLUSION

For CSM with hypo-lordosis, FCK was a risk factor for poor postoperative outcomes. Surgeons may consider treating the FCK simultaneously if the focal kyphotic Cobb angle of FCK is greater than 4.05° and is accompanied by cervical global kyphotic or sigmoid deformity.

The Role of Osteobiologics in Augmenting Spine Fusion in Unplated Anterior Cervical Discectomy and Fusion Compared to Plated Constructs: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To compare clinical and radiographic outcomes as well as complications of unplated vs plated anterior cervical discectomy and fusion (ACDF) surgery considering the role of osteobiologics in single- and multi-level procedures.

METHODS

A systematic search of PubMed/MEDLINE, Scopus, CINAHL, EMBASE, CENTRAL, Cochrane and ClinicalTrials.gov databases was performed. Briefly, we sought to identify studies comparing unplated vs. plated ACDF for cervical degenerative disc disease reporting the use of osteobiologics in terms of clinical outcomes, radiographic fusion, and complications. Data on study population, follow-up time, type of cage and plate used, type of osteobiologic employed, number of levels treated, patient-reported outcomes (PROs), radiographic outcomes and complications were collected and compared. Relevant information was pooled for meta-analyses.

RESULTS

Thirty-eight studies met the inclusion criteria. No significant difference was found in terms of clinical outcomes between groups. Unplated ACDF was characterized by reduced blood loss, operation time and length of hospital stay. Fusion was achieved by the majority of patients in both groups, with no evidence of any specific contribution depending on the osteobiologics used. Dysphagia was more commonly associated with anterior plating, while cage subsidence prevailed in the unplated group.

CONCLUSION

Unplated and plated ACDF seem to provide similar outcomes irrespective of the osteobiologic used, with minor differences with doubtful clinical significance. However, the heterogeneity and high risk of bias affecting included studies markedly prevent significant conclusions.

Comparison study of anterior cervical zero-profile fusion cage (ROI-C) and traditional titanium plate plus fusion technique for the treatment of spinal cord type cervical spondylosis

A retrospective comparative study. To compare and analyze the differences in the efficiency and safety of ROI-C and traditional titanium plate with fusion cage for the treatment of CSM patients. Clinical data of 105 patients with CSM who underwent surgical treatment at our hospital from January 2019 to December 2020 were retrospectively reviewed. Patients were divided into ROI-C and traditional groups according to the different fusion methods. The operation time, intraoperative blood loss, preoperative and postoperative JOA score, NDI score, cervical Cobb angle, intervertebral space height, and postoperative complications were recorded and compared between the 2 groups. A total of 105 patients were included in this study, with 57 patients in the ROI-C group and 48 patients in the traditional group. The baseline data were similar between the 2 groups (P > .05). The operative time, intraoperative blood loss, and the incidence of postoperative dysphagia were significantly lower in the ROI-C group than in the traditional group (P < .05). There were no significant differences in the JOA score, NDI score, cervical Cobb angle, intervertebral space height, the incidence of postoperative axial symptoms, and adjacent segment degeneration between the 2 groups (P > .05). However, both groups showed significant improvement in the JOA score, NDI score, cervical Cobb angle, and intervertebral space height compared with before surgery (P < .05). The ROI-C zero-profile internal fixation system and traditional titanium plates with fusion cages can achieve satisfactory clinical treatment results for CSM patients. However, ROI-C has advantages of a shorter operative time, less blood loss, and less postoperative dysphagia. Therefore, the ROI-C zero-profile internal fixation system can be safely and effectively used to treat patients with CSM.

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.

Anterior cervical tunnectomy and fusion (ACTF): a novel technique for cervical canal decompression

OBJECTIVE

To describe a novel surgical technique note coined as anterior cervical tunnectomy and fusion (ACTF) which applying on removal of posterior vertebral bony protrusions or soft extrusions.

METHODS

Total twenty-three patients from January 2016 to January 2021 who experienced with spinal cord compression and performed by ACTF were retrospectively reviewed. Herein, relevant information including patient's gender, age, BMI, intraoperative time, intraoperative blood loss, postoperative complications and postoperative hospitalized stay were collected. Furthermore, JOA and VAS score were both collected. Moreover, imaging parameters were measured and calculated on radiographs. Correlated data were analyzed by t test. Significance was considered when P < 0.05.

RESULTS

All patients in this study were validated with favorable outcomes and none of postoperative complications. The Nurick grade of patients dramatically deceased postoperation (P < 0.001). And postoperative VAS score of patients (P < 0.001), as well as JOA score (P < 0.001), was given dramatical significance comparing to preoperation. Furthermore, occupying rate (OR) (P < 0.001) was obviously reduced while space available cord (SAC) (P < 0.001) and diameter of spinal cord (P < 0.001) was significantly increased postoperation. Meanwhile, disc height of involved segment, C2-7 SVA, and C2-C7 Cobb angle were measured on sagittal plane of lateral radiograph. Postoperative disc height of involved segment (P < 0.001) significantly elevated comparing to preoperation. However, there were no significance on C2-7 SVA (P = 0.460) and C2-C7 Cobb angle (P = 0.097).

CONCLUSIONS

The novel surgical technique coined by ACTF is a practicable approach during taking charge of bony and soft narrowing behind vertebral space.

Biomechanical performance of the novel assembled uncovertebral joint fusion cage in single-level anterior cervical discectomy and fusion: A finite element analysis

Introduction: Anterior cervical discectomy and fusion (ACDF) is widely accepted as the gold standard surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the low fusion rate in the early period after ACDF surgery using the Zero-P fusion cage. We creatively designed an assembled uncoupled joint fusion device to improve the fusion rate and solve the implantation difficulties. This study aimed to assess the biomechanical performance of the assembled uncovertebral joint fusion cage in single-level ACDF and compare it with the Zero-P device.

Methods: A three-dimensional finite element (FE) of a healthy cervical spine (C2−C7) was constructed and validated. In the one-level surgery model, either an assembled uncovertebral joint fusion cage or a zero-profile device was implanted at the C5–C6 segment of the model. A pure moment of 1.0 Nm combined with a follower load of 75 N was imposed at C2 to determine flexion, extension, lateral bending, and axial rotation. The segmental range of motion (ROM), facet contact force (FCF), maximum intradiscal pressure (IDP), and screw−bone stress were determined and compared with those of the zero-profile device.

Results: The results showed that the ROMs of the fused levels in both models were nearly zero, while the motions of the unfused segments were unevenly increased. The FCF at adjacent segments in the assembled uncovertebral joint fusion cage group was less than that that of the Zero-P group. The IDP at the adjacent segments and screw–bone stress were slightly higher in the assembled uncovertebral joint fusion cage group than in those of the Zero-P group. Stress on the cage was mainly concentrated on both sides of the wings, reaching 13.4–20.4 Mpa in the assembled uncovertebral joint fusion cage group.

Conclusion: The assembled uncovertebral joint fusion cage provided strong immobilization, similar to the Zero-P device. When compared with the Zero-P group, the assembled uncovertebral joint fusion cage achieved similar resultant values regarding FCF, IDP, and screw–bone stress. Moreover, the assembled uncovertebral joint fusion cage effectively achieved early bone formation and fusion, probably due to proper stress distributions in the wings of both sides.

Anterior and Posterior Approaches for 4-Level Degenerative Cervical Myelopathy: Low-Profile Cage Versus Cervical Pedicle Screws Fixation

(1) Background: The choice of surgical access for 4-level degenerative cervical myelopathy (DCM) remains controversial, and the clinical and radiological outcomes of anterior surgery using a low-profile cage (Low-P) versus posterior surgery using cervical pedicle screw fixation (CPS) have not been compared. (2) Methods: This is a retrospective controlled study conducted between January 2019 and June 2021 of 72 patients with 4-level DCM who underwent ACDF using a low-profile cage (n = 39) or laminectomy and instrument fusion using CPS (n = 33). The minimum follow-up time was 12 months. The outcomes were C2−7Cobb angle, C2−7sagittal vertical axis (SVA) fusion rate, the Japanese Orthopedic Association (JOA) score, pain visual analog scale (VAS), neck disability index (NDI), and complications. (3) Results: Both anterior and posterior procedures significantly improved the patients’ quality-of-life parameters. Anterior cervical convexity and SVA significantly increased in both groups, but the SVA was greater in the posterior group than in the anterior group (p < 0.001). The C2−7 Cobb angle significantly improved in both groups postoperatively, and at the final follow-up, there was a slight but nonsignificant reduction in cervical lordosis in both groups (p = 0.567). There was a longer operative time, less intraoperative blood loss, and reduced mean hospital stay in the anterior group compared to the posterior group, with two cases of postoperative hematoma requiring a second operation, two cases of axial pain (AP), five cases of dysphagia, two cases of c5 palsy in the anterior group, and four cases of axial pain, and three cases of c5 palsy in the posterior group. According to Bridwell fusion grade, anterior fusion reached grade I in 28 cases (71.8%) and grade II in 10 cases (25.6%) in the anterior group, and posterior fusion reached grade I in 25 cases (75.8%) and grade II in 8 cases (24.2%) in the posterior group. (4) Conclusions: There was no difference between the anterior and posterior surgical approaches for MDCM in terms of improvement in neurological function. Posterior surgery using CPS achieved similar recovery of cervical anterior convexity as anterior surgery with a shorter operative time but was more invasive and had a greater increase in SVA. The use of Low-P in anterior surgery reduced the incidence of dysphagia and cage subsidence and was less invasive, but with a longer operative time.

Is 3D-printed Titanium cage a reliable option for 3-level anterior cervical discectomy and fusion in treating degenerative cervical spondylosis?

Background

To assess the clinical and radiographical outcomes of 3-level anterior cervical discectomy and fusion (ACDF) with a 3D-printed titanium cage in treating degenerative cervical spondylosis.

Methods

In this study, 25 patients with degenerative cervical spondylosis who underwent 3-level ACDF using a 3D-printed titanium cage from March 2019 to June 2021 were retrospectively enrolled. The patient-reported outcome measures (PROMs) were evaluated by visual analog scale (VAS) for the neck (VAS-neck) and arm pain (VAS-arm), Neck Disability Index (NDI) score, Japanese Orthopedic Association (JOA) score, SF-12 concise health survey, and the Odom criteria. The radiographical parameters, including C2-C7 lordosis, segmental angle, segmental height, and subsidence, were assessed. The mean duration of follow-up was 25.6 months.

Results

Bony fusion was achieved in all patients (100%). In three patients (12%) mild dysphagia was observed during the follow-up. The VAS-neck, VAS-arm, NDI score, JOA score, SF-12 score, C2-C7 lordosis, and segmental angle improved noticeably at the latest follow-up. Based on the Odom criteria, 22 patients (88%) reported satisfactory (excellent or good). The mean loss of C2-C7 lordosis and segmental angle between the immediate postoperative and the latest follow-up values were 1.6° ± 0.5° and 1.1° ± 0.5°, respectively. The mean subsidence was 0.9 ± 0.6 mm.

Conclusion

In patients with multi-level degenerative cervical spondylosis, 3-level ACDF using the 3D-printed titanium cage can effectively relieve the symptoms, stabilize the spine, and restore segmental height and cervical curvature. It is proven to be a reliable option for patients with 3-level degenerative cervical spondylosis. However, a future comparative study involving a larger population and longer follow-up time may be required to further evaluate the safety, efficacy and outcomes of our preliminary results.

Role of a Qualified Physician and Health Behavior in Effective Treatment of Cervical Spondylotic Myelopathy

Objectives: This research investigated the impact of having a qualified physician on improving disease awareness and effective treatment for cervical spondylotic myelopathy. Previous studies have observed that patients with cervical spondylotic myelopathy are less satisfied with their treatment and medical facilities. This study hence aimed to investigate the role of a qualified physician and the moderating influence of health behavior between disease awareness and effective treatment for cervical spondylotic myelopathy. Methods: The primary data was collected from 144 cervical spondylotic myelopathy patients admitted in Meram Medical Faculty Hospital. A questionnaire on 5-point Likert scale was developed, whose items were checked for validity and reliability. The study adopted a cross- sectional approach, by conducting a normality test, correlation measurement of all variables like disease awareness, qualified physician and health behavior, and a regression analysis to explore the impact of independent variables on the dependent variable, and to test the hypotheses of the study. Results: The results of this research revealed that patients of cervical spondylotic myelopathy would get effective treatment when their health behavior is positive and when they have an awareness of the critical health situation. Conclusion: This research contributed a framework significantly to the research gap. It demonstrated the extraordinary practical and theoretical implications related to cervical spondylotic myelopathy. Future directions are also recommended by highlighting the limitations of this research, in order to continue to contribute to the effective treatment of cervical spondylotic myelopathy patients.

Changes in cervical alignment of Zero-profile device versus conventional cage-plate construct after anterior cervical discectomy and fusion: a meta-analysis

BACKGROUND

Anterior cervical diskectomy and fusion (ACDF) has been widely accepted as a gold standard for patients with cervical spondylotic myelopathy (CSM). However, there was insufficient evidence to compare the changes in the cervical alignment with different fusion devices in a long follow-up period. This meta-analysis was performed to compare the radiologic outcomes and loss of correction (LOC) in cervical alignment of Zero-profile (ZP) device versus cage-plate (CP) construct for the treatment of CSM.

METHODS

Retrospective and prospective studies directly comparing the outcomes between the ZP device and CP construct in ACDF were included. Data extraction was conducted and study quality was assessed independently. A meta-analysis was carried out by using fixed effects and random effects models to calculate the odds ratio and mean difference in the ZP group and the CP group.

RESULTS

Fourteen trials with a total of 1067 participants were identified. ZP group had a lower rate of postoperative dysphagia at the 2- or 3-month and 6-month follow-up than CP group, and ZP group was associated with a decreased ASD rate at the last follow-up when compared with the CP group. The pooled data of radiologic outcomes revealed that there was no significant difference in postoperative and last follow-up IDH. However, postoperative and last follow-up cervical Cobb angle was significantly smaller in the ZP group when compared with the CP group. In subgroup analyses, when the length of the last follow-up was less than 3 years, there was no difference between two groups. However, as the last follow-up time increased, cervical Cobb angle was significantly lower in the ZP group when compared with the CP group.

CONCLUSION

Based on the results of our analysis, the application of ZP device in ACDF had a lower rate of postoperative dysphagia and ASD than CP construct. Both devices were safe in anterior cervical surgeries, and they had similar efficacy in correcting radiologic outcomes. However, as the last follow-up time increased, ZP group showed greater changes cervical alignment. In order to clarify the specific significance of LOC, additional large clinical studies with longer follow-up period are required.

Is the Zero-P Spacer Suitable for 3-Level Anterior Cervical Discectomy and Fusion Surgery in Terms of Sagittal Alignment Reconstruction: A Comparison Study with Traditional Plate and Cage System

The Zero-P spacer was primarily developed aiming to reduce the morbidity associated with the traditional anterior cervical plate. During the past decade, many authors have reported the use of Zero-P spacers for anterior cervical discectomy and fusion (ACDF) of one or two segments. Nevertheless, there is still a paucity of knowledge on the safety and feasibility of using Zero-P spacers for 3-level fixation. The objective of this study was to investigate the clinical and radiological outcomes, with a focus on the sagittal alignment reconstruction of 3-level ACDF surgery using Zero-P spacers versus those using a traditional plate and cage system. From Sep 2013 to Aug 2016, a total of 44 patients who received 3-level ACDF surgery due to cervical spondylotic myelopathy were recruited. The Zero-P spacer was used in 23 patients (group ZP) and the traditional plate and cage system in 21 (group PC). Clinical outcomes were analyzed by Neck Disability Index (NDI) and Japanese Orthopedic Association (JOA) scores, and dysphagia was evaluated using the Bazaz score. Radiological outcomes, including fusion rate, adjacent segment degeneration (ASD), and especially changes in cervical sagittal alignment, were analyzed. The NDI and JOA scores did not differ significantly between the two groups postoperatively (p > 0.05); however, there was significantly less dysphagia in patients using Zero-P spacers at the 3- and 6-month follow-up (p < 0.05). At the 24-month follow-up, the fusion rate and ASD were similar between the two groups (p > 0.05). Interestingly, patients using Zero-P spacers had a significantly lower postoperative C2-7 Cobb angle and fused segment Cobb angle, compared to those using a traditional plate and cage system (p < 0.05); meanwhile, the fused segment disc wedge was also found to be significantly smaller in patients using Zero-P spacers after surgery (p < 0.05). Moreover, we further divided patients into subgroups according to their cervical lordosis. In patients with a preoperative C2-7 Cobb angle ≤ 10°, significantly less cervical and local lordosis, as well as disc wedge, were seen in group ZP after surgery (p < 0.05), while in others with a preoperative C2-7 Cobb angle > 10°, no significant difference in postoperative changes of the cervical sagittal alignment was seen between group ZP and group PC (p > 0.05). Zero-P spacers used in 3-level ACDF surgery could provide equivalent clinical outcomes and a lower rate of postoperative dysphagia, compared to the traditional plate and cage system. However, our results showed that it was inferior to the cervical plate in terms of sagittal alignment reconstruction for 3-level fixation. We recommend applying Zero-P spacers for 3-level ACDF in patients with good preoperative cervical lordosis (C2-7 Cobb angle > 10°), in order to restore and maintain physiological curvature of the cervical spine postoperatively.

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.

Application of a new integrated low-profile anterior plate and cage system in single-level cervical spondylosis: a preliminary retrospective study

Background

Although ACDF has been widely used in treating cervical spondylosis and related diseases, the complications along with this anterior surgical technique have hindered its application and affected the postoperative outcome of the patients. Here, we investigated the clinical and radiological outcomes of a new integrated low-profile anterior plate and cage system for anterior cervical discectomy and fusion (ACDF) in treating cervical spondylosis.

Methods

A total of 96 cervical spondylosis patients who underwent single-level ACDF between 2018 to 2020 in our institute were enrolled. There were 28 patients using the new implants and 68 patients using the zero-profile (Zero-P) implants. The Japanese Orthopedic Association (JOA) score and the visual analog scale (VAS) were used to evaluate the clinical outcomes. The cervical and segmental Cobb angle and range of motion (ROM) were used to assessed the radiological outcomes. Incidence of complications were also recorded. All data were recorded at pre-operation, 6-month and 12-month post-operation.

Results

All patients were followed-up for at least 1-year, the mean follow-up time was over one year. The fusion rate was similar in the two groups. There was no significant difference in the postoperative JOA score recovery rate, postoperative VAS score of neck and arm pain, postoperative ROM, and incidence of complications between two groups (P > 0.05). However, postoperative cervical and segmental Cobb angle were better maintained in the new low-profile implant group compared to Zero-P group.

Conclusions

The clinical outcomes of the new low-profile implant were satisfactory and comparable to that of zero-profile system. It may have advantages in improving and maintaining the cervical lordosis, and can be an alternative device for single-level cervical spondylosis treated with ACDF.

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.

Long-term Radiologic and Clinical Outcomes after Three-level Contiguous Anterior Cervical Diskectomy and Fusion without Plating: A Multicentric Retrospective Study

BACKGROUND

 Anterior cervical diskectomy and fusion (ACDF) has been providing good surgical, clinical, and radiologic outcomes in patients suffering from cervical degenerative disk disease (DDD). However, the role of anterior plating is still debated, especially in three-level procedures. This study aimed to investigate long-term clinical and radiologic outcomes and complications after three-level contiguous ACDF without plating for cervical DDD.

METHODS

 Two institutional databases were retrieved (January 2009-December 2014) for patients treated with three-level contiguous ACDF without plating. Minimum follow-up (FU) was 5 years. Demographical data, smoking status, implant types, Neck Disability Index (NDI), visual analog scale (VAS) for neck pain, complications, fusion rate, adjacent segment degeneration (ASD), cervical lordosis (CL), and residual segmental mobility were evaluated.

RESULTS

 We enrolled 21 patients. Tantalum and carbon fiber cages were implanted, respectively, in 13 and 8 patients. The mean FU length was 5.76 ± 0.87 years. Mean NDI score was 78.29 ± 9.98% preoperatively and 8.29 ± 1.67% at last FU (p < 0.01), whereas mean VAS score decreased from 7.43 ± 1.14 preoperatively to 0.95 ± 0.95 at last FU (p < 0.01). Complications were one postoperative hematoma, one superficial wound infection, and five cases of postoperative dysphagia (recovered within 3 days). The fusion rate was 90% and ASD was reported in three (14%) cases. The mean CL was 6.33 ± 2.70 degrees preoperatively, 8.19 ± 1.97 degrees 3 months after surgery (p = 0.02), and 7.62 ± 1.96 degrees at latest FU. There was no residual mobility on every operated segment at last FU. The smoking status was an independent risk factor for nonfusion in this case series (p = 0.02).

CONCLUSIONS

 Three-level contiguous ACDF without plating seems to be an effective treatment for cervical DDD. Properly designed comparative clinical trials are needed to further investigate this topic.