Influence of Anterior Cervical Plate Design on Dysphagia

Zero-Profile Stand-Alone Cages Versus Traditional Cage-and-Plate Constructs in Single and Multi-Level Anterior Cervical Discectomy and Fusion: A Propensity-Matched Analysis Using Validated Fusion Assessment Methods

ObjectivesStand-alone (SA) and anterior cage-and-plate (ACP) have been studied in anterior cervical discectomy and fusion (ACDF). However, fusion assessment methods vary and existing studies are not propensitymatched and often lack patient-reported outcomes (PROMs). We compare fusion rates between propensity-matched single- and multi-level SA versus ACP using a method validated by intraoperative motion testing during revision surgery. We also compare sagittal alignment, perioperative outcomes, and PROMs.MethodsPatients >18 years who underwent primary ACDF were included. 2:1 propensity score matching was performed. Fusions were assessed using 1 year computer tomography and flexion/extension radiographs via validated fusion assessment methods. ALOD was assessed at least 6-months postoperatively. Sagittal alignment was assessed at preoperative, short-term postoperative (2-6 weeks), and long-term postoperative (6 months or more) time points. PROMs, operative time, blood loss, dysphagia, and complications were analyzed.Results153 patients (51 SA) were included after matching. There were no differences in fusion rates overall (P = .662), or by number of surgical levels. There were no differences in ALOD at upper or lower levels, nor was there a difference in ALOD grade. Regarding segmental lordosis, overall lordosis, T1 slope, TS-CL, and PROMs (NDI, SF-12 PCS, VAS neck and arm), there were no differences at preoperative or any postoperative time point. Operative time and blood loss were greater in the ACP cohort, with no differences in complications or postoperative dysphagia.ConclusionsFusion rates, PROMs, radiographic outcomes, complications, and dysphagia rates were all comparable following single and multi-level ACDF between SA and ACP.

Table-mounted Versus Self-retaining Retraction: An Assessment of Postoperative Dysphagia Following Anterior Cervical Spine Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVE

To determine whether there are significant differences in postoperative dysphagia when using table-mounted versus self-retaining retractor tools.

SUMMARY OF BACKGROUND DATA

Retraction of prevertebral structures during anterior cervical spine surgery (ACSS) is commonly associated with postoperative dysphagia or dysphonia. Retractors commonly used include nonfixed self-retaining retraction devices or fixed table-mounted retractor arms. However, there is a paucity of literature regarding differences in dysphagia between retractor types.

METHODS

Patients who underwent ACSS and adhered to a minimum of 6-month follow-up were retrospectively evaluated. Patient-reported outcomes (PROs) were compared between table-mounted and self-retaining retractor groups at the preoperative and final postoperative time points, including the SWAL-QOL survey for dysphagia. Categorical dysphagia was assessed using previously defined values for the minimum clinically important difference (MCID).

RESULTS

Overall, 117 and 75 patients received self-retaining or table-mounted retraction. Average follow-up was significantly longer in the self-retaining cohort (14.8±15.0 mo) than in the table-mounted group (9.4±7.8, P =0.005). No differences were detected in swallowing function ( P =0.918) or operative time ( P =0.436), although 3-level procedures were significantly shortened with table-mounted retraction ( P =0.005). Multivariate analysis trended toward worse swallow function with increased operative levels ( P =0.072) and increased retraction time ( P =0.054), although the retractor used did not predict swallowing function ( P =0.759). However, categorical rates of postoperative dysphagia were lower with table-mounted retraction (13.3% vs. 27.4%, P =0.033).

CONCLUSIONS

There was no significant difference observed in long-term swallowing dysfunction between patients who underwent ACSS with self-retaining and table-mounted retractors, although the rate of dysphagia was lower with table-mounted retraction. In addition, the greater number of operated levels per case in the table-mounted group at a similar time suggests improved efficiency.

Comparison of Stand-Alone Anchored Spacer and Plate-Cage Construct for Surgical Treatment of Multilevel Cervical Degenerative Spondylopathy: A Meta-Analysis

Study DesignMeta-analysis study.ObjectivesWe aimed to compare clinical outcomes, radiologic parameters, and complications between the stand-alone anchored spacer and the plate-cage construct as treatment options for patients with multilevel cervical degenerative spondylopathy involving 3 or 4 levels.MethodsIn this meta-analysis, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search for relevant studies covered the Embase, PubMed, and Cochrane Central Register of Controlled Trials databases, encompassing data from the inception of each database up to July 1, 2024.ResultsThe analysis included 12 studies, involving a total of 817 patients. Patients in the stand-alone anchored spacer group exhibited decreased intraoperative blood loss and shorter surgical durations. Clinical outcomes, including visual analog scale (VAS) scores, Japanese Orthopaedic Association (JOA) scores, Neck Disability Index (NDI) scores, and Odom's criteria for clinical outcomes, demonstrated no significant differences between the two groups. Radiographic outcomes revealed no statistically significant difference in fusion rates between stand-alone cages and plate-cage constructs. However, the plate-cage group exhibited more favorable maintenance of segmental angle and cervical alignment (C2-C7 angle).ConclusionsBoth stand-alone anchored spacer and plate-cage constructs are viable treatment options for patients with cervical degenerative spondylopathy involving more than two levels. Stand-alone cages have the benefit of reducing intraoperative blood loss and shortening surgical durations, but they are associated with a higher risk of cage subsidence. Plate-cage constructs offer better maintenance of segmental angle and cervical alignment; however, they carry a higher risk of dysphagia.

Long-term effectiveness of stand-alone anchored spacer in multilevel anterior cervical discectomy and fusion compared with cage-plate system: a systematic review and meta-analysis

OBJECTIVE

For anterior cervical discectomy and fusion (ACDF), stand-alone anchored spacers (SAAS) and cage-plate system (CPS) are currently employed. However, controversy remains over the effectiveness and security of these two apparatuses in multilevel ACDF. The aim of this study was to demonstrate the global long-term effectiveness and safety of SAAS versus CPS with multilevel ACDF.

METHODS

We conducted a systematic review of studies comparing SAAS with CPS for multilevel ACDF using four electronic databases. Data from this meta-analysis were analyzed with Stata MP 17.0.

RESULTS

A total of nine trials comprising 584 patients were selected for inclusion. SAAS significantly reduced operative time, intraoperative bleeding and the incidence of postoperative dysphagia compared with CPS. The SAAS group exhibited significantly smaller cervical sagittal angle (CSA) and fusion segmental height (FSH) compared to CPS group. At final follow-up, the rate of cage sinking was higher in SAAS group compared to CPS group. At the endpoint, there was no difference in JOA score, NDI score, fusion rate or the incidence of adjacent segment degeneration (ASD).

CONCLUSIONS

SAAS provided comparable long-term effectiveness and safeness for multilevel ACDF regarding JOA scores, NDI scores, fusion rates and ASD rates at endpoint compared to CPS. In comparison to CPS, SAAS demonstrated significant advancement in the reduction of operative time, intraoperative blood loss and the incidence of postoperative dysphagia. As a consequence, SAAS appeared more desirable than CPS among people who needed multilevel ACDF. Yet in long-term observation, SAAS was inferior to CPS in maintaining CSA and FSH and in preventing cage descent. However, whether or not radiographic abnormality has an impact on clinical presentation awaits confirmation from research with more longitudinal follow-up.

Reducing Dysphagia Following Anterior Cervical Spine Surgery: Insights From a Meta-Analysis

A systematic search was conducted across PubMed, Embase, and Cochrane Library databases to identify relevant studies. The analysis focused on the influence of surgical duration, the number of cervical levels treated, and implant types. A total of 21 studies were included, and heterogeneity among studies was evaluated using the I² statistic.  The results indicated that longer surgeries, multi-level procedures, and certain implant designs were associated with an increased risk of dysphagia. In contrast, low-profile implants and stand-alone cage systems demonstrated a reduced risk compared to traditional plate-and-cage constructs. Anterior plates and specific cage designs were linked to higher dysphagia rates. The findings suggest that the risk of dysphagia after anterior cervical spine surgery (ACSS) is influenced by the length of surgery, the number of motion segments treated, and implant design. Optimizing these factors could help reduce postoperative complications and improve patient outcomes.

Comparative efficacy of zero-profile implant and conventional cage-plate implant in the treatment of single-level degenerative cervical spondylosis: a systematic review and meta-analysis

BACKGROUND

In recent years, the zero-profile implant (Zero-p) has emerged as a promising internal fixation technique. Although studies have indicated its potential superiority over conventional cage-plate implant (Cage-plate) in the treatment of degenerative cervical spondylosis, there remains a lack of definitive comparative reports regarding its indications, safety, and efficacy.

METHODS

A computerized search was conducted on English and Chinese databases, including PubMed, Web of Science, Cochrane Library, EMBASE, CNKI, Wanfang and VIP. Additionally, a manual search was meticulously carried out on Chinese medical journals, spanning from the inception of the respective databases until August 2023. The meta-analysis utilized a case-control study approach and was executed through the utilization of RevMan 5.3 software. Stringent quality evaluation and data extraction procedures were implemented to guarantee the reliability and validity of the findings.

RESULTS

Nine high-quality studies with 808 patients were included. Meta-analysis showed that the operation time (MD = - 13.28; 95% CI (- 17.53, - 9.04), P < 0.00001), intraoperative blood loss (MD = - 6.61; 95% CI (- 10.47, - 2.75), P = 0.0008), incidence of postoperative dysphagia at various time points: within the first month after surgery (OR = 0.36; 95% CI (0.22, 0.58), P < 0.0001), 1-3 months after surgery (OR = 0.20; 95% CI (0.08, 0.49), P = 0.0004), the final follow-up (OR = 0.21; 95% CI (0.05, 0.83), P = 0.003) and the rate of postoperative adjacent disc degeneration (OR = 0.46; 95% CI (0.25, 0.84), P = 0.01) were significantly lower in the Zero-p group than in the Cage-plate group. Additionally, was also significantly lower in the Zero-p group. However, there were no significant differences in the JOA score, the final follow-up NDI score, surgical segmental fusion rate, postoperative height of adjacent vertebrae, or postoperative subsidence rate between the two groups.

CONCLUSION

In summary, when treating single-segment degenerative cervical spondylosis, both internal fixation techniques are reliable and effective. However, Zero-P  implant offer several advantages over cage-plate implant, including shorter operation duration, less intraoperative blood loss, reduced postoperative dysphagia, and slower adjacent disc degeneration. Additionally, Zero-P implant has a broader application space, making them a preferred choice in certain cases.

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.

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

STUDY DESIGN

Systematic Review and Meta-Analysis.

OBJECTIVES

This study aimed to evaluate the clinical and radiological outcomes of surgically treated adjacent segment disease (ASDis) following ACDF with either anterior plate construct (APC) or stand-alone anchored spacers (SAAS).

METHOD

Multiple databases were searched until December 2022 for pertinent studies. The primary outcome was health-related quality of life outcomes [JOA, NDI, and VAS], whereas, the secondary outcomes included operative characteristics [estimated blood loss (EBL) and operative time (OT)], radiological outcomes [C2-C7 Cobb angle, disc height index (DHI) changes, fusion rate], and complications.

RESULTS

A total of 5 studies were included, comprising 210 patients who had been surgically treated for cervical ASDis. Among them, 113 received APC, and 97 received SAAS. Postoperative dysphagia was significantly higher in the APC group [47% vs 11%, OR = 7.7, 95% CI = 3.1-18.9, P < .05]. Similarly, operative time and blood loss were higher in the APC group compared to the SAAS group; [MD = 16.96, 95% CI = 7.87-26.06, P < .05] and [MD = 5.22, 95% CI = .35 - 10.09, P < .05], respectively. However, there was no difference in the rate of prolonged dysphagia and clinical outcomes in terms of JOA, NDI, and VAS. Furthermore, there was no difference in the radiological parameters including the C2-7 Cobb angle and DHI as well as the fusion rate.

CONCLUSION

Our meta-analysis demonstrated that both surgical techniques (APC and SAAS) are effective in treating ASDis. However, with low certainty of the evidence, considering patients are at high risk of dysphagia following revision cervical spine surgery SAAS may be the preferred choice.

Anterior cervical discectomy and fusion with a zero-profile VA spacer device: a clinical and radiological study with two-year follow-up

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to compare clinical and radiological outcomes of the anterior cervical discectomy and fusion (ACDF) with a novel zero-profile variable-angle (Zero-P VA) spacer and a traditional poly-ether-ether-ketone (PEEK) cage and plate system in cases pertaining to cervical radiculopathy/myelopathy. There are two conventional types of ACDF procedures aimed at treating symptomatic cervical spondylosis. The first one involves an uninstrumented "stand-alone" approach utilizing bone graft/cage, while the second incorporates bone graft/cage in conjunction with a front plate positioned before the vertebral bodies. Both procedures have their own inherent advantages and disadvantages. The Zero-P VA spacer, however, represents a unique synthesis by amalgamating the advantages of both traditionally typical procedures. Notably, this spacer can potentially circumvent the issue related to prevertebral soft-tissue disturbance and reduce the occurrence of dysphagia.

METHODS

Using our surgical database, the authors systematically conducted a retrospective analysis encompassing all patients who underwent single-level ACDF between January 2018 and January 2019, with a minimum two-year follow-up. Patients either received a Zero-P VA implant or PEEK cage coupled with plating. The Japanese Orthopedic Association (JOA) score and Visual Analogue Scale (VAS) for arm and neck pain were documented. Dysphagia was evaluated using the Eating Assessment Tool-10 (ETA-10). Additional parameters such as cervical alignment, fusion rate and the incidence of postoperative complications were assessed.

RESULTS

According to the outcomes of the statistical analysis, there was no substantial disparity that emerged in the advancements observed in the JOA and VAS metrics between the two study cohorts. Noteworthy, however, the ETA-10 scores were statistically significantly reduced in the Zero-P VA group compared to the cage and plating group (p < 0.05). At the final follow-up, there were no statistically significant differences in the height of the operated segment, Cobb angle of the fused segment, C2-C7 Cobb angle and fusion rate between the two groups (p > 0.05). However, postoperative complications were slightly lower in patients with the Zero-P VA group (7.69%) as compared to the cage and plating group (16.67%).

CONCLUSION

The clinical outcomes observed with the Zero-P VA spacer used for single-level ACDF were found to be satisfactory. The performance of this device is comparable or even superior to the traditional cage and plating method in preventing postoperative dysphagia and mitigating potential complications associated with the use of a plate.

Relative Efficacy of Cervical Total Disc Arthroplasty Devices and Anterior Cervical Discectomy and Fusion for Cervical Pathology: A Network Meta-Analysis

STUDY DESIGN

Systematic Review and Meta Analysis.

OBJECTIVE

This study sought to compare patient-reported outcomes, success, complications, and radiographic outcomes directly and indirectly between different cervical total disc arthroplasty (TDA) devices and anterior cervical discectomy and fusion (ACDF).

METHODS

Patients of prospective randomized controlled trials of 1-level cervical TDA with a minimum of 2 years follow up were identified in the literature. A frequentist network meta-analysis model was used to compare each outcome across the different TDA devices included and ACDF using the mixed effect sizes.

RESULTS

15 studies were included for quantitative analysis, reporting the outcomes of 2643 patients with an average follow-up was 67.3 months (range: 24-120 months), 1417 of whom underwent TDA and 1226 of whom underwent ACDF. Nine TDA devices were compared to ACDF, including the Bryan, Discover, Kineflex, M6, Mobi-C, PCM, Prestige ST, ProDisc-C, and Secure-C cervical prostheses. Several devices outperformed ACDF for certain outcomes, including Visual Analog Scale (VAS) Arm, Physical Component Score of the Short-Form Health Survey (SF PCS), neurological success, satisfaction, index-level secondary surgical interventions (SSI), and adjacent level surgeries. Cumulative ranking of each intervention assessed demonstrated the highest performance with the M6 prosthesis (P = .70), followed by Secure-C (P = .67), PCM (P = .57), Prestige ST (P = .57), ProDisc-C (P = .54), Mobi-C (P = .53), Bryan (P = .49), Kineflex (P = .49), Discover (P = .39), and ACDF (P = .14).

CONCLUSION

Cervical TDA was found to be superior on most outcomes assessed in the literature of high-quality clinical trials. While most devices demonstrated similar outcomes, certain prostheses such as the M6 were found to outperform others across several outcomes assessed. These findings suggest that the restoration of near-normal cervical kinematics may lead to improved outcomes.

Biomechanical analysis of the door-shaped titanium plate in single-level anterior cervical discectomy and fusion

BACKGROUND

Analyse and discuss the immediate stability of the cervical spine after anterior cervical discectomy and fusion using a door-shaped titanium plate and compare it with the traditional titanium plate, to provide biomechanical evidence for the rationality and effectiveness of the door-shaped titanium plate in clinical applications.

METHODS

Ten adult goat C4/5 vertebral bodies were obtained, and models were prepared using denture base resin. Biomechanical experiments were performed on the specimens before internal fixation. MTS was used to conduct non-destructive biomechanical loading tests in six directions, including flexion, extension, left-right bending, and left-right torsion, recording the range of motion (ROM) and neutral zone (NZ) of each specimen. The specimens were then randomly divided into two groups: the study group was fixed with a door-shaped titanium plate, and the control group was fixed with a traditional titanium plate. ROM and NZ in each direction were measured again. After measurements, both groups were subjected to 0.5 Hz torsion loading with a torque of 2 N m for a total of 3000 cycles, followed by measuring ROM and NZ in six directions once more.

RESULTS

Compared to before fixation, ROM and NZ in both groups significantly decreased in all six directions after fixation, with statistical significance (P < 0.05); after fixation, the study group showed slightly lower values for various mechanical reference parameters compared to the control group, with no statistical significance (P > 0.05); after 3000 torsional loads, both internal fixation groups showed increased ROM and NZ compared to after fixation but to a lower extent, and no screw or titanium plate loosening was observed. Compared to before fixation, the differences were still statistically significant (P < 0.05), with the study group having slightly lower ROM and NZ values in all directions compared to the control group, with no statistical significance (P > 0.05).

CONCLUSION

The door-shaped titanium plate exhibits mechanical properties similar to the traditional titanium plate in all directions, and its smaller size and simpler surgical operation can be used for anterior cervical endoscopic surgery, reducing surgical trauma. It is clinically feasible and deserves further research and promotion.

Postoperative Measurement of the Retropharyngeal Space Predicts the Risk of Dysphagia After Anterior Cervical Diskectomy and Fusion

BACKGROUND AND OBJECTIVES

Postoperative dysphagia is a common complication of anterior cervical diskectomy and fusion (ACDF), although its pathophysiology remains poorly understood. Patients with severe dysphagia may suffer from serious complications such as aspiration pneumonia, in addition to difficulty with oral intake or malnutrition; therefore, a prompt indicator for postoperative management would be helpful. We quantitatively evaluated the retropharyngeal space (RS) after ACDF and investigated its association with postoperative dysphagia.

METHODS

This multicenter retrospective study analyzed the clinical data of 82 consecutive patients who underwent ACDF. The anteroposterior distance (APD) of the RS was measured at the C2 level using a lateral radiographic view on postoperative day 1. Postoperative dysphagia was subjectively assessed using the Bazaz-Yoo Dysphagia Severity Scale. We statistically evaluated the association between the APD of the RS and postoperative dysphagia.

RESULTS

The mean APD of the RS in all 82 patients was 3.6 mm preoperatively and significantly increased to 8.2 mm postoperatively (P < .0001). Twenty-two patients (26.8%) had postoperative dysphagia. Multivariable analysis revealed that the postoperative APD was associated with postoperative dysphagia (odds ratio 1.27, 95% CI 1.10-1.50, P = .0007). The receiver operating characteristic curve (area under the curve 0.70, 95% CI 0.58-0.83) demonstrated that the postoperative APD of the RS cutoff value was 6.1 mm, with a sensitivity of 100% and a specificity of 35%. With this cutoff value, the positive and negative predictive values for postoperative dysphagia were 36% and 100%, respectively.

CONCLUSION

Our data demonstrate that a value of 6.1 mm for the APD of the RS is an effective indicator for dysphagia after ACDF, which contributes to optimizing the patient management in the acute postoperative period.

Hybrid fixation versus conventional cage-plate construct in 3-level ACDF: Introduce the "seesaw theory" of stand-alone cage

STUDY DESIGN

A retrospective study.

BACKGROUND

Conventional cage-plate construct (CCP) was widely used in anterior cervical discectomy and fusion (ACDF), but the rigid fixation limits the motion of fused segments. Self-locking stand-alone cage (SSC) was an alternative for ACDF procedures and showed several superiorities. However, the effect of hybrid fixation in 3-level ACDF remains unknown.

OBJECTIVE

To assess the clinical and radiological outcomes of hybrid fixation with SSC and CCP against conventional CCP in 3-level ACDF.

METHOD

A retrospective review of patients who underwent 3-level ACDF at Renji Hospital between January 2018 and December 2019 was performed. Eighty-three patients met the inclusion and exclusion criteria and were stratified into 2 groups based on the fixation methods. The clinical outcomes, functional outcomes, and radiological parameters were collected and analyzed.

RESULTS

No significant difference was observed between the two groups in the mean age, sex, body mass index, hospital stay, and duration of follow-up. The postoperative C2-7 Cobb angle in the CCP group was significantly greater than that in the hybrid group. The rate of cervical proximal junctional kyphosis (CPJK) in the hybrid group was significantly lower than that in the CCP group. The CCP group suffered significantly higher rates of adjacent segment degeneration (ASD) than the hybrid group at 2 years postoperatively. Moreover, the incidence of postoperative dysphagia was lower in the hybrid group. No significant differences were observed in JOA and NDI scores between the two groups.

CONCLUSION

The hybrid fixation achieved comparable clinical outcomes against CCP fixation, indicating that hybrid fixation is an alternative procedure in 3-level ACDF.

Interbody Cage Placement Without Plate Supplementation Adjacent to Plated Segments in Multilevel Anterior Cervical Decompression and Fusion

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To evaluate the clinical efficacy and safety of hybrid anterior cervical fixation, focusing on stand-alone segments.

SUMMARY OF BACKGROUND DATA

In the treatment of multilevel cervical stenosis, the number of segments fixed using a plate is limited by placing an interbody cage without plate supplementation at one end of the surgical segment to reduce long plate-related problems. However, the stand-alone segment may experience cage extrusion, subsidence, cervical alignment deterioration, and nonunion.

METHODS

Patients who underwent three-segment or four-segment fixation for cervical degenerative disease and completed one-year follow-up were included in this study. Patients were divided into two groups: a cranial group, with stand-alone segments located at the cranial end adjacent to plated segments, and a caudal group, with stand-alone segments located at the caudal end. Differences in radiographic outcomes between the groups were evaluated. Fusion was defined using dynamic radiographs or computed tomography. To identify factors associated with nonunion in stand-alone segments, multivariable logistic regression analyses were performed. To identify factors associated with cage subsidence, multiple regression analyses were performed.

RESULTS

A total of 116 patients (mean age, 59±11 y; 72% male; mean fixed segments, 3.7±0.5 segments) were included in this study. No case showed cage extrusion or plate dislodgement. In stand-alone segments, the fusion rate was significantly lower in the caudal group than in the cranial group (76% vs. 93%, P =0.019). Change in the cervical sagittal vertical axis was worse in the caudal group than in the cranial group (2.7±12.3 mm vs. -2.7±8.1 mm, P =0.006). One caudal group patient required additional surgery because of nonunion at the stand-alone segment. Multivariable logistic regression indicated factors associated with nonunion included the location of the stand-alone segment (caudal end: OR 4.67, 95% CI, 1.29-16.90), larger pre-disk space range of motion (OR 1.15, 95% CI, 1.04-1.27), and lower preoperative disk space height (OR 0.57, 95% CI, 0.37-0.87). Multiple regression analysis indicated that higher cage height and lower pre-disk space height were associated with cage subsidence.

CONCLUSION

Hybrid anterior cervical fixation with stand-alone interbody cage placement adjacent to plated segments may avoid long plate-related problems. Our results suggest that the cranial end of the construct may be more suitable for the stand-alone segment than the caudal end.

Zero-P and ROI-C implants versus traditional titanium plate with cage to treat cervical spondylotic myelopathy: clinical and radiological results with 5 years of follow-up

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is the gold standard for treating cervical spondylotic myelopathy (CSM). While implanting plates in ACDF may increase the risk of complications. Zero-P and ROI-C implants have been gradually applied for CSM.

METHODS

150 patients with CSM were retrospectively analyzed from January 2013 to July 2016. Group A consisted of 56 patients who received traditional titanium plates with cage. 94 patients underwent ACDF using zero-profile implants and were divided into 50 patients with the Zero-P device (Group B) and 44 with the ROI-C device (Group C). Related indicators were measured and compared. The clinical outcomes were evaluated by JOA, VAS, and NDI scores.

RESULTS

Compared with group A, group B and C had a less blood loss and shorter operation time. The JOA and VAS scores improved significantly from pre-operative to 3 months postoperative and last follow-up in three groups. The cervical physiological curvature and segmental lordosis at final follow-up were higher than that of pre-operation (p < 0.05). Dysphagia rate, adjacent level degeneration rate, and Osteophyma rate was the highest in group A (p < 0.05). The bone graft fusion was achieved at the final follow-up in three groups. There were no statistical significance in fusion rate and subsidence rate among the three groups.

CONCLUSIONS

ACDF with Zero-P or ROI-C implants can also obtain satisfactory clinical outcomes compared to traditional titanium plate with cage after 5 years follow-up. The zero-profile implant devices carry a simple operation, short operation time, less intraoperation blood loss, and incidence of dysphagia.

Self-locking stand-alone cage versus cage-plate fixation in monosegmental anterior cervical discectomy and fusion with a minimum 2-year follow-up: a systematic review and meta-analysis

BACKGROUND

Currently, self-locking stand-alone cages (SSC) are commonly applied in anterior cervical discectomy and fusion (ACDF), as are cage-plate constructs (CPC). However, it remains controversial concerning the long-term effectiveness of both apparatuses. Our purpose is to compare long-term effectiveness of SSC with CPC in monosegmental ACDF.

METHODS

Four electronic databases were queried to identify studies comparing SSC versus CPC in monosegmental ACDF. The meta-analysis was carried out with the use of the Stata MP 17.0 software package.

RESULTS

Ten trials with 979 patients were included. Compared to CPC, SSC significantly reduced operative time, intraoperative blood loss, duration of hospitalisation, cervical Cobb angle at final follow-up, 1-month postoperative dysphagia rate, and incidence of adjacent segment degeneration (ASD) at final follow-up. No significant difference was found regarding 1-month postoperative cervical Cobb angle, JOA scores, NDI scores, fusion rate and cage subsidence rate at final follow-up.

CONCLUSION

Both devices achieved similar long-term effectiveness in monosegmental ACDF regarding JOA scores, NDI scores, fusion rate and cage subsidence rate. SSC had significant advantages over CPC in reducing surgical duration, intraoperative bleeding, duration of hospitalisation, as well as rates of dysphagia and ASD after surgery. Therefore, SSC is a better option than CPC in monosegmental ACDF. However, SSC is inferior to CPC in maintaining cervical curvature at long-term follow-up. Whether radiological changes affect clinical symptoms needs confirmation in trials with longer follow-up.

The Effect of Plate Thickness on Fusion, Complications, and Outcomes in Anterior Cervical Spine Surgery

Background and objective Anterior cervical discectomy and fusion (ACDF) is a common surgery involving the cervical spine. The goals of ACDF include obtaining a solid fusion and minimizing complications such as dysphagia. The effect of plate thickness on fusion, dysphagia, and patient outcomes is not well established. In light of this, this study aimed to evaluate the effect of plate thickness on fusion rates, complications, and outcomes in ACDF. Methods A case-control study involving ACDF performed by a single surgeon was conducted with the aim of comparing two commercially available plating systems: the Medtronic plate (Atlantis Vision Elite, Medtronic, Memphis, TN) and Aegis plate (CastleLoc-P, Aegis, Englewood, CO). The patients treated with the Medtronic plate served as the control group (Std) as the plate is widely utilized, while those treated with the Aegis plate, which is touted as one of the thinnest plates on the market, constituted the case low-profile group (LP). Demographic variables, fusion status, and patient-reported outcome measures (PROM) were compared between the two systems. Results Baseline demographic data were not significantly different between groups. The LP plate group had a significantly lower rate of fusion per patient as well as per level at 12 months. PROM did not significantly differ at any time point between the groups. Dysphagia scores could be correlated with radiographic measures reported in the Prevertebral Soft Tissue Swelling - Index (PVSTS-I).  Conclusion Based on our findings, the plate thickness was not associated with dysphagia rates; however, the use of a thinner plate correlated with a lower rate of radiographic fusion at 12 months. The PVSTS-I may be useful for identifying patients with abnormal and severely abnormal dysphagia scores.

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.

A scoping review of the methods used to capture dysphagia after anterior cervical discectomy and fusion: the need for a paradigm shift

OBJECTIVE

Dysphagia is the most commonly reported complication of annterior cervical discectomy and fusion (ACDF) surgery. However, the incidence of dysphagia post-ACDF varies widely-partly attributable to differing outcome measures used to capture dysphagia. Our objective was to conduct a scoping review of the literature to quantify which dysphagia outcome measures have been employed post-ACDF and examine trends by study design, year, and location.

METHODS

After removing duplicates, 2396 abstracts were screened for inclusion. A total of 480 studies were eligible for full-text review. After applying exclusion criteria, data was extracted from 280 studies. We extracted the dysphagia outcome measure(s), study design (prospective vs retrospective), year, and location (country). Approximately 10% of studies were repeated for intra-rater agreement.

RESULTS

In total, 317 dysphagia outcome measures were reported in 280 studies (primarily retrospective-63%). The largest proportion of outcome measures were categorized as "unvalidated patient-reported outcome measures" (46%), largely driven by use of the popular Bazaz scale. The next most common categories were "insufficient detail" and "validated patient-reported outcome measures" (both 16%) followed by "chart review/database" (13%) and instrumental assessment (7%). Studies examining dysphagia post-ACDF steadily increased over the years and the use of validated measures increased in the past 10 years.

CONCLUSIONS

This scoping review of the literature highlights that nearly half of the ACDF dysphagia literature relies on unvalidated patient-reported outcome measures. The current understanding of the mechanism, timeline, and presentation of dysphagia post-ACDF are likely limited due to the metrics that are most commonly reported in the literature.

Dysphagia after cervical spine surgery: a review of risk factors and preventative measures

Dysphagia is a regular occurrence after cervical spine surgery, and the development of dysphagia postoperatively is associated with worsened quality of life for patients. Despite the frequency and negative implications of this adverse outcome, there is no clear consensus for defining dysphagia within the spinal literature. Numerous patient-reported outcomes questionnaires are currently used to elucidate the presence and severity of postoperative dysphagia, several of which are not validated instruments. This variability in reporting creates difficulty when trying to determine the prevalence of dysphagia and any potential mitigating factors. In the current review, the authors discuss the causes of postoperative dysphagia after cervical spine surgery, metrics for evaluating postoperative dysphagia, risk factors for the development of this adverse outcome, and strategies for preventing its development. Readers will be able to use this information to improve patient outcomes after cervical spine surgery.

Upper Instrumented Vertebrae, Number of Levels Fused, and Plate Morphology Do Not Affect Severity of Chronic Dysphagia After Anterior Cervical Spine Surgery

BACKGROUND

Disordered swallowing, or dysphagia, is the most common complication after anterior cervical spine (ACS) surgery. Many operative factors are associated with development of dysphagia. The aim of this study was to explore how number of levels instrumented, specific levels fused, and plate morphology affect chronic dysphagia after ACS surgery.

METHODS

Consecutive patients referred to a tertiary center for otolaryngology evaluation for chronic dysphagia after ACS surgery between 2012 and 2017 were enrolled. Basic demographic data were obtained. Plain radiographs were reviewed for number of levels fused, upper instrumented vertebrae, and plate morphology. Plate morphology was categorized as a closed, small window, large window, or no profile plate. The 10-item Eating Assessment Tool (EAT-10) was used to assess dysphagia severity.

RESULTS

Of 171 patients referred for dysphagia, 126 met inclusion criteria; 54% were female, with a mean age of 63 years (range, 32-88 years). Mean EAT-10 score was 18.5 ± 10.1. Mean time from spine surgery to videofluoroscopic swallow study for dysphagia was 58.3 months. Mean number of levels fused was 2.2 ± 0.9. There were no significant differences in EAT-10 scores in single-level versus multilevel fusion (19.0 vs. 18.4, P = 0.76) as well as with regard to upper instrumented vertebrae or plate morphology.

CONCLUSIONS

In this series of patients with chronic dysphagia following ACS surgery, the severity of dysphagia as measured by the EAT-10 was not affected by upper instrumented vertebrae, number of levels fused, or plate morphology.

The clinical efficacy of anterior cervical discectomy and fusion with ROI-C device vs. plate-cage in managing traumatic central cord syndrome

Purpose

To assess the efficacy and complications of anterior cervical discectomy and fusion (ACDF) with ROI-C device vs. conventional anterior plate and cage system (APCS) in managing traumatic central cord syndrome (TCCS).

Methods

A total of 37 patients diagnosed with TCCS who underwent ACDF with ROI-C implant and APCS were recruited in this retrospective study from June 2012 to February 2020. Radiological parameters and clinical results were recorded and compared through follow-up time. Characteristics of patients and complications were also recorded.

Results

All patients tolerated the procedure well. The average follow-up time was 25.00 ± 7.99 months in the ROI-C group, and 21.29 ± 7.41 months in the APCS group. The blood loss and operation time were significantly lower in the ROI-C group than in the APCS group. Radiological parameters and clinical results were all improved postoperatively and maintained at the final follow-up. Fusion was achieved in all patients. ROI-C group had a lower incidence of postoperative dysphagia than the APCS group. Only 1 case of ALD was observed at the final follow-up in the APCS group.

Conclusions

Both ROI-C device and APCS demonstrated satisfactory clinical effects and safety in managing symptomatic single-level traumatic central cord syndrome with underlying instability. Both techniques could improve and maintain cervical lordosis and disc height. ROI-C device was related to a lower incidence of postoperative dysphagia, shorter operation time, and less blood loss.

Comparing Clinical and Radiographic Outcomes Between the Self-locking Stand-alone Cage and Conventional Cage-plate Construct: A Five-year Retrospective Cohort Study

STUDY DESIGN/SETTING

A retrospective cohort study.

OBJECTIVE

To evaluate the clinical efficacy of the self-locking stand-alone (SA) cage and conventional cage-plate construct (CPC) in treating degenerative cervical spondylosis with a five-year follow-up.

SUMMARY OF BACKGROUND DATA

The SA approach was designed to reduce complications associated with traditional anterior cervical discectomy and fusion. These techniques have been shown to have satisfactory short-term clinical outcomes. Literature describing the mid-term clinical outcomes of SA cage is limited.

MATERIALS AND METHODS

We retrospectively analyzed patients with cervical spondylosis who had received an SA device or CPC between 2014 and 2016 at the Xijing Hospital. Participants were matched for sex, age, and operative level. Differences in clinical and radiographic outcomes and the occurrence of postoperative complications between the two groups were analyzed.

RESULTS

In total, 207 patients were included (101 with SA and 106 with CPC), the median follow-up for both groups were 60.2 and 60.9 months. Both groups exhibited significant improvements in all measured values compared with the preoperative values. The SA group had a shorter operation time, less intraoperative blood loss, and a significantly lower incidence of dysphagia after surgery than the CPC group ( P <0.05). At the last visit, cage subsidence was 6.9% and 3.8% in the SA and CPC groups, respectively ( P =0.365). The radiographic adjacent segment degeneration (ASD) was significantly lower in the SA group than in the CPC group (6.9% vs. 27.4%, P <0.01). No symptomatic ASD was observed in the SA group, and six (5.7%) cases occurred in the CPC group ( P =0.029).

CONCLUSIONS

In this study, the SA cage showed similar efficacy to that of the conventional CPC in treating cervical spondylosis using anterior cervical discectomy and fusion, with a significant reduction in the incidence of immediate postoperative dysphagia and mid-term ASD.

The improved bioactive n-HA/PA66 cage versus the PEEK cage in anterior cervical fusion: results from a 6-year follow-up and a case-matched study

BACKGROUND

The nanohydroxyapatite/polyamide 66 (n-HA/PA66) cage, a bioactive nonmetal cage, is fabricated in a hollow cylindrical shape and has been widely used for decades with good clinical outcomes for anterior cervical fusion. However, there remain some radiological complications, such as a slightly high subsidence rate. To improve the clinical outcomes, the improved n-HA/PA66 cage now has been developed into a trapezoidal and wedge shape, a better biomechanical shape matching the cervical spine that is similar to that of the PEEK cage. However, there have been no long-term comparisons of the improved n-HA/PA66 cage and PEEK cage in anterior cervical reconstruction.

METHODS

Fifty-eight patients who underwent single-level anterior cervical decompression and fusion (ACDF) with the improved n-HA/PA66 cage (n-HA/PA66 group) were matched with patients with the PEEK cage (PEEK group) by clinical presentation, segment, age and sex. All patients underwent a minimum of 6 years of follow-up. The radiographic parameters (cage subsidence, fusion status, cervical lordosis, and segmental sagittal alignment) and clinical parameters (10-point visual analogue scale, Neck Disability Index and Japanese Orthopedic Association scores) from patients were evaluated before surgery, immediately after surgery, and at the latest follow-up.

RESULTS

The n-HA/PA66 and PEEK groups were well matched in terms of clinical presentation, segment, age, and sex at surgery. The n-HA/PA66 and PEEK cages had similar fusion rates at 6 months postoperatively (n-HA/PA66: 58.6% vs. PEEK: 51.7%, P = 0.455) and at the last follow-up (n-HA/PA66: 96.6% vs. PEEK: 93.1%, P = 0.402). The respective cage subsidence rates in the n-HA/PA66 and PEEK groups were 6.9 and 12.1% (P = 0.342). The correction of SA was similar between the groups at the final follow-up (n-HA/PA66: 4.29 ± 1.99 vs. PEEK: 3.99 ± 2.59 P = 0.464). There were no significant differences between the two groups in mean cervical lordosis, visual analogue scale scores of the neck and arm, NDI scores, JOA scores or patients' overall satisfaction at the final follow-up.

CONCLUSION

After single-level ACDF, the improved n-HA/PA66 cage had similar excellent results in both radiological and clinical outcomes compared with the PEEK cage over 6 years of follow-up. According to these results, the improved n-HA/PA66 cage and the PEEK cage could be comparable for ACDF.

Realistic long-term dysphagia rates after anterior cervical discectomy with fusion: is there a correlation with postoperative sagittal alignment and lordosis at a minimum 2-year follow-up?

OBJECTIVE

Postoperative dysphagia after anterior cervical discectomy and fusion (ACDF) has many contributing factors, and long-term data are sparse. The authors evaluated dysphagia after ACDF based on levels fused and cervical sagittal parameters.

METHODS

Patients who underwent ACDF between 2009 and 2018 at the University of California, San Francisco (UCSF), were retrospectively studied. Dysphagia was evaluated preoperatively, immediately postoperatively, and at last follow-up using the UCSF dysphagia score. Dysphagia was categorized as normal (level 7), mild (levels 5 and 6), moderate (levels 3 and 4), and severe (levels 1 and 2). The UCSF mild dysphagia score was further classified as "minimal dysphagia," while moderate and severe dysphagia were classified as "significant dysphagia." "Any dysphagia" included any dysphagia, regardless of grade. Cervical sagittal parameters were measured preoperatively, immediately postoperatively, and at last follow-up.

RESULTS

A total of 131 patients met inclusion criteria. The mean follow-up was 43.89 (24-142) months. Seventy-eight patients (59.5%) reported dysphagia immediately postoperatively, and 44 patients (33.6%) reported some dysphagia at last follow-up (p < 0.001). The rates of moderate dysphagia were 13.0% immediately postoperatively and 1.5% at the last follow-up (p < 0.001). Twenty-two patients (16.8%) had significant dysphagia immediately postoperatively, and 2 patients (1.5%) had significant dysphagia at last follow-up (p < 0.001). Patients with immediate postoperative dysphagia had less C2-7 preoperative lordosis (-9.35°) compared with patients without (-14.15°, p = 0.029), but there was no association between C2-7 lordosis and dysphagia at last follow-up (p = 0.232). The prevalence rates of immediate postoperative dysphagia and long-term dysphagia were 87.5% and 58.3% in ≥ 3-level ACDF; 64.0% and 40.0% in 2-level ACDF; and 43.9% and 17.5% in 1-level ACDF, respectively (p < 0.001).

CONCLUSIONS

The realistic incidence of any dysphagia after ACDF was 59.5% immediately postoperatively and 33.6% at the minimum 2-year follow-up, higher than previously published rates. However, most dysphagia was not severe. The number of fused levels was the most important risk factor for long-term dysphagia, but not for immediate postoperative dysphagia. Loss of preoperative C2-7 lordosis was associated with immediate postoperative dysphagia, but not long-term dysphagia. ACDF segmental lordosis and cervical sagittal vertical axis were not associated with long-term dysphagia in ACDF.

Anterior cervical plating combined with zero-profile anchored spacer for the treatment of cervical facet dislocation in elderly patients

OBJECTIVE

The purpose of this study was to evaluate the efficacy of anterior cervical plating combined with zero-profile (Z-P) anchored spacer for the treatment of cervical facet dislocation in elderly patients.

METHODS

This is a retrospective study. Twelve elderly patients (from 57 to 77 years old, averaged 65 years) with unilateral or bilateral facet dislocation of sub-axial cervical spine from September 2015 to September 2019 surgically treated at the authors' hospital were enrolled in this study. The patients with osteoporosis or osteopenia were all surgically treated by anterior-only procedure using cervical plating combined with zero-profile anchored spacer after closed manual reduction under general anesthesia and spinal cord monitoring. The operation times (OT), estimated blood loss (EBL), perioperative complications, were recorded. The clinical evaluation included visual analogue scales (VAS) and the American Spinal Injury Association (ASIA) scale. The radiographic evaluation included kyphotic angle (KA) and disc height (DH) and the fusion rate.

RESULTS

Anterior discectomy, interbody fusion and fixation were performed in all patients after the disloctions were reduced by manual maneuver. The average OT was 66 minutes, with a range from 45 to 110 minutes. The EBL averaged 42 ml per surgical procedure, with a range from 20 to 60 ml. The VAS, ASIA, KA were improved significantly after surgery (P<0.05). The average follow-up time was 24.2 months, with a range from 12 to 38 months. There were no statistical differences between the immediately post-op KA and KA at the last follow-up (P>0.05). No disc space subsidence was observed statistically (P<0.05) Interbody fusion was obtained in all patients. Two patient experienced slight difficulty in swallowing, which were improved 6 weeks later. There were no hardware failure, no segmental instability, no wound infection or other complications.

CONCLUSIONS

Manual reduction with spinal cord monitoring under general anesthesia is a safe and efficient option and the anterior cervical plating combined with Z-P spacer could achieve reliable fixation for the patients with cervical facet dislocation in the elderly patients with osteoporosis or osteopenia.

Comparison of the Postoperative Motion Stabilization Between Anterior Cervical Decompression and Fusion with a Zero-Profile Implant System and a Plate-Cage Construct

OBJECTIVE

Due to the lack of an additional anterior plate, the motion stability of a zero-profile device with an anchored cage (AC) may be inferior to that of a traditional plate-cage construct (PCC). However, the impact of this difference in motion stability on various outcomes has not been fully explored. Therefore, the aim of this study was to compare the motion stabilization features of an AC and a PCC and analyze their impact on postoperative outcomes and complications.

METHODS

A retrospective study of patients treated with single-level anterior cervical discectomy and fusion from January 2008 to May 2016 was performed. First, clinical and radiological outcomes, postoperative complications and time to achieve motion stabilization were compared between the AC and PCC groups. Then, based on the time to achieve motion stabilization, all patients were divided into group A (time to achieve motion stabilization <3 months), group B (time to achieve motion stabilization from 3-6 months), and group C (time to achieve motion stabilization >6 months). The early postoperative complications were compared across the 3 groups. Motion stabilization was measured on dynamic cervical radiographs using the interspinous process method and Cobb angle method according to previously published methods.

RESULTS

A total of 160 patients met the inclusion criteria, including 90 patients in the AC group and 70 patients in the PCC group. There were no significant differences between the AC and PCC groups in the clinical outcomes, C2-7 angle change, segmental angle change, final fusion rate or adjacent-level degeneration (P > 0.05). The disc height loss was 2.26 ± 1.00 mm in the AC group and 1.76 ± 1.13 mm in the PCC group (P = 0.004), and the incidence of implant subsidence was 24.44% in the AC group and 11.43% in the PCC group (P = 0.036). In addition, the PCC was more dynamically stable than the AC at 3 months post-surgery (P < 0.001), and at this time, the disc height loss and implant subsidence in motion-stable patients were significantly lower than those in motion-unstable patients (P < 0.05). Furthermore, our results also showed that when the arrival time of motion stabilization was prolonged, the loss of disc height and occurrence of subsidence gradually increased.

CONCLUSIONS

More attention should be given to minimizing the adverse impact of poor motion stability in the design and development of future zero-profile cervical implants, although this has little impact on clinical efficacy.

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.

Comparative analysis of the biomechanics of anterior cervical discectomy and fusion with multiple segmental plates fixation versus single multilevel plate fixation: a finite element study

BACKGROUND

This study aimed to compare the biomechanical differences between anterior cervical discectomy and fusion (ACDF) with multiple-level separate plates and conventional long plates by using finite element analysis.

METHODS

The following four finite element models were created to simulate various fixations: (1) C4-6 ACDF with multiple plates, (2) C4-6 ACDF with a single plate, (3) C3-6 ACDF with multiple plates, and (4) C3-6 ACDF with a single plate. The maximum Von-mises stress of the cage and fixation, compressive force of the adjacent intervertebral discs and range of motion (ROM) of different segments in the four models were calculated and analyzed.

RESULTS

For C4-6 ACDF, the maximum Von-mises stress of the cage and fixation was lower in the multiple plate fixation model in all motion states. Similarly, for the C3-6 ACDF models, the peak stress of the C3-4 and C5-6 cages was lower with multiple plates fixation in all motions but the stress of the C4-5 cage in the multiple plates model was slightly higher in flexion, bending and rotation. Besides, applying multiple plates in C3-6 ACDF models resulted in a decreased maximum stress of the fixation under different motions except for bending. In both the C4-6 ACDF and C3-6 ACDF models, the ROM values of the adjacent motion segments were lower in the multiple plates models in extension, bending and rotation. In the C4-6 ACDF models, the peak stress on the adjacent intervertebral discs in the multiple plates models was slightly smaller. In C3-6 ACDF models, the maximum stress on the adjacent intervertebral discs was larger in the single-plate model under flexion, bending and rotation movements.

CONCLUSION

Multiple plates fixation has a positive effect on increasing stiffness and maintaining the ROM of adjacent segments, indicating lower risk of construct failure and adjacent segment degeneration. Further studies are required to confirm its efficacy in clinical practice.

Dysphagia as a Postoperative Complication of Anterior Cervical Discectomy and Fusion

Anterior cervical discectomy and fusion (ACDF), despite its possible complications, remains the gold standard for the surgical treatment of patients with radiculopathy and/or myelopathy caused by cervical intervertebral disc herniation or spondylosis. Despite its high rate of incidence, postoperative dysphagia following ACDF is still poorly understood; its pathogenesis remains relatively unknown, and its risk factors are still a subject of debate.

The aim of this study is to review the incidence, pathogenesis, diagnosis, and methods of prevention of dysphagia in ACDF patients. To this end, a literature review was conducted based on the PubMed internet database. Article titles were searched by using the following keywords: “dysphagia” and “anterior cervical discectomy and fusion” or “ACDF”. The search was limited to prospective clinical studies evaluating dysphagia after ACDF surgery. Studies published in non-English languages, retrospective studies, cadaveric studies, reviews, case reports, study protocols, and commentary studies were excluded.

Initially, 335 studies were identified after a primary search. After the application of the exclusion criteria, 73 studies remained for the final analysis. This literature review focused on identifying the rate of dysphagia and the various risk factors leading to this complication by comparing and evaluating the current literature with a wide spectrum of heterogeneity concerning patients, surgeons, and surgical techniques. A mean dysphagia rate of 19.4% (95% CI: 9.6%-29.1%) based on the findings of the included studies correlating dysphagia directly with ACDF procedures was calculated. Various established risk factors leading to dysphagia include the female sex, smoking, the surgical approach, rhBMP-2 use, and multilevel surgery, while zero-profile devices seem to reduce dysphagia risk. The diagnosis is based on clinical and radiological findings, especially prevertebral soft-tissue swelling. However, videofluoroscopic and endoscopic studies have been recently used for the evaluation of dysphagia. The role of local administration of steroids in the prevention of dysphagia has not yet been clarified. This review underscores the prevailing rudimentary understanding of the problem of dysphagia after ACDF procedures and highlights the need for more sensitive, factor-specific studies for understanding the impact of various risk factors on the incidence rate of dysphagia.

Efficacy and safety of anterior cervical discectomy and fusion (ACDF) through mini-incision and posterior laminoplasty (LAMP) for treatment of long-level cervical spondylosis: a retrospective cohort study

BACKGROUND

The efficacy and safety of anterior cervical discectomy and fusion (ACDF) through mini-incision and posterior laminoplasty for long-level cervical spondylosis were investigated.

METHOD

From January 2018 to September 2019, clinical patients data with 3-4 segments (C3-7) cervical spondylotic radiculopathy, cervical spondylotic myelopathy, or mixed cervical spondylosis who received ACDF (42 cases) throughwith mini-incision or LAMP (36 cases) treatment were retrospectively collected and analyzed. The operative time, bleeding volume, incisive length, and hospital stay were recorded. Moreover, the intervertebral height, functional segment height, cervical lordosis, cervical hyperextension and hyperflexion range-of-motion (ROM) and ROM in all directions of the cervical spine before and after the operation were measured. Additionally, all relevant postoperative complications were also recorded. Then, the therapeutic effects of both surgical methods were investigated.

RESULTS

Patients in the ACDF group had less bleeding, shorter incision, and fewer hospitalization days than the LAMP group. There was no significant difference in JOA, VAS score of the upper limb, NDI score after surgery between two groups. Postoperative intervertebral height and functional segment height in the ACDF group were significantly higher than those before the operation, and postoperative functional segment height of the ACDF group was significantly higher than that of the LAMP group. Moreover, the postoperative cervical lordosis angle in the ACDF group was significantly larger than the LAMP group. There was no significant difference between preoperative and postoperative ROM in all directions of the cervical spine for the two groups.

CONCLUSIONS

Both ACDF through mini-incision and LAMP are effective treatments for long-level cervical spondylosis. However, ACDF through mini-incision shows minor trauma, less bleeding, fast recovery, and it is beneficial for cervical lordosis reconstruction.

The surgical outcome of multilevel anterior cervical discectomy and fusion in myelopathic elderly and younger patients

The elderly population has an increased risk of degenerative cervical myelopathy due to multilevel disease, causing motor and sensory dysfunctions and a poor quality of life. Multilevel anterior cervical discectomy and fusion (ACDF) is an alternative surgical treatment option, but has a perceived higher risk of complications. The goal of this study is to report the outcome. We retrospectively reviewed patients from 2006 to 2019 undergoing multilevel ACDF for degenerative cervical myelopathy and compared outcomes and complications between elder patients (aged 70 and above) and younger patients (below 70). The patients' comorbidities, and postoperative complications, radiographic parameters such as C2-C7 Cobb angle, C2-C7 sagittal vertical axis, inter-body height of surgical levels and fusion rate were recorded. Japanese Orthopaedic Association (JOA) score and modified Odom's score were collected. Included were 18 elderly (mean age 74, range 70-87) and 45 young patients (mean age 56, range 43-65) with a follow-up of 43.8 and 55.5 months respectively. Three-level ACDF was the most common. The ratios of ASA class III patients were 94.4% and 48.9% (p < 0.001). The Charlson comorbidity indexes were 4.3 ± 1.03 and 2.1 ± 1.11 (p < 0.001). The average lengths of hospital stays were 4.9 and 4.6 days. Eleven patients (61.1%) in the elderly group experienced at least one short-term complication, compared with 16 patients (35.6%) in the younger group (p < 0.05). The middle-term complications were comparable (22.2% and 20.0%). The JOA score, recovery rate and modified Odom score showed comparable result between groups. Despite its extensiveness, multilevel ACDF is feasible for the elder patients with good clinical outcome and fusion rate. When compared to younger cohort, there is a trend of lower preoperative JOA score and recovery rate. The short-term complication rate is higher in the elderly group.

Cervical non-fusion using biomimetic artificial disc and vertebra complex: technical innovation and biomechanics analysis

Background

Changes in spinal mobility after vertebral fusion are important factors contributing to adjacent vertebral disease (ASD). As an implant for spinal non-fusion, the motion-preserving prosthesis is an effective method to reduce the incidence of ASD, but its deficiencies hamper the application in clinical. This study designs a novel motion-preserving artificial cervical disc and vertebra complex with an anti-dislocation mechanism (MACDVC-AM) and verifies its effect on the cervical spine.

Methods

The MACDVC-AM was designed on the data of healthy volunteers. The finite element intact model, fusion model, and MACDVC-AM model were constructed, and the range of motion (ROM) and stress of adjacent discs were compared. The biomechanical tests were performed on fifteen cervical specimens, and the stability index ROM (SI-ROM) were calculated.

Results

Compared with the intervertebral ROMs of the intact model, the MACDVC-AM model reduced by 28–70% in adjacent segments and increased by 26–54% in operated segments, but the fusion model showed the opposite result. In contrast to the fusion model, the MACDVC-AM model diminished the stress of adjacent intervertebral discs. In biomechanical tests, the MACDVC-AM group showed no significant difference with the ROMs of the intact group (p > 0.05). The SI-ROM of the MACDVC-AM group is negative but close to zero and showed no significant difference with the intact group (p > 0.05).

Conclusions

The MACDVC-AM was successfully designed. The results indicate that the MACDVC-AM can provide physiological mobility and stability, reduce adjacent intervertebral compensatory motion, and alleviate the stress change of adjacent discs, which contributes to protect adjacent discs and reduce the occurrence of ASD.

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.

Revision Surgery for Symptomatic Adjacent Segment Disc Degeneration after Initial Anterior Cervical Fusion: Is ROI-C Better than Plate-Cage Construct?

The optimal revision surgical strategy for patients who develop symptomatic adjacent segment disc degeneration (ASD) is controversial. The risks of intraoperative complications, especially the incidence of dysphagia, were relatively high for revision surgeries. This study was aimed at comparing the efficacy of revision surgery using a traditional plate-cage construct and zero-profile anchored spacer (ROI-C) device in treating symptomatic ASD after initial anterior cervical discectomy and fusion (ACDF) surgery. Forty-two patients who developed symptomatic ASD were retrospectively analyzed and classified into two groups (plate-cage group and ROI-C group). The clinical and radiological results were compared. We further evaluated the complication of dysphagia and dysphagia-related risk factors in these patients. The JOA and NDI scores, C2-7 lordotic angle, and intervertebral space height were significantly improved after revision surgery in both groups. The operative time and intraoperative blood loss both significantly decreased in the ROI-C group. The incidence of postoperative dysphagia was much lower in the ROI-C group than in the plate-cage group (18.75% vs. 57.69%; P = 0.01). The presence of dysphagia after initial surgery (P = 0.003) and revision surgery type (P = 0.01) was significantly related to the presence of dysphagia after revision surgery. These results indicated that both the plate-cage construct and ROI-C are effective in treating symptomatic ASD. However, compared with the traditional plate-cage construct, ROI-C with less operative time, less blood loss, and lower incidence of dysphagia is more suitable. Furthermore, ROI-C should preferably be used for patients who present with dysphagia after initial cervical surgery. This study will provide clinical guidance for spinal surgeons to choose the zero-profile device in treating specific and complicated cases, which will significantly improve the therapeutic efficacy of symptomatic adjacent segment degeneration.

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.

Bibliometric and visualized analysis of the top 100 most-cited articles on anterior cervical surgery

Anterior cervical surgery (ACS) owes its development to various pioneering individuals whose revolutionary works form key advances and guide current medical decisions. This bibliometric study aimed to identify, analyse and visualize the main features of the most-cited papers in ACS.

The citation count for the top 100 most-cited articles ranged from 148 to 1,197, and citations per year ranged from 3.1 to 89.8. The articles were published from 1958 to 2016, with the 2000s being the most active decade. There was an inverse correlation between the average citations per year since publication and article age.

The oldest as well as most-cited two articles were both published in 1958 by Smith and Robinson, and Cloward, respectively. In their studies, the authors individually described the technique of anterior cervical discectomy with fusion (ACDF).

The most popular keywords were: ‘fusion’ (22), ‘spine’ (20), ‘cervical spine’ (16), ‘complications’ (15), ‘arthrodesis’ (13), ‘interbody fusion’ (13), ‘bone morphogenetic protein’ (13), and ‘radiculopathy’ (12).

ACDF was the most frequent surgical procedure (80%), while cervical disc arthroplasty is of gradual greater impact.

The surgical techniques of ACDF have remained unaltered for over 60 years. More attempts are needed to promote its development.

Cite this article: EFORT Open Rev 2021;6:1203-1213. DOI: 10.1302/2058-5241.6.210074

Risk Factors for Dysphagia after Anterior Cervical Discectomy and Fusion with the Zero-P implant system: A Study with Minimum of 2 Years Follow-up

OBJECTIVE

To evaluate the risk factors for dysphagia after anterior cervical discectomy and fusion (ACDF) with the Zero-P Implant System by multidimensional analysis and investigated the predictive values of these risk factors for dysphagia.

METHODS

A retrospective analysis of 260 patients who underwent ACDF with the Zero-P Implant System and had at least 2 year of follow-up were performed. All patients were divided into a non-dysphagia group and a dysphagia group. Sex, age, body mass index (BMI), intraoperative time, estimated blood loss, diabetes mellitus, hypertension, smoking, alcohol consumption, prevertebral soft-tissue thickness, the levels of surgery, O-C₂ angle, C_2-7 angle, T₁ slope and segmental angle were analyzed. The Modified Japanese Orthopaedic Association (JOA) scoring system was used to determine functional status. NDI was used to evaluate neck pain and disability. The Bazaz grading system was chosen to evaluate dysphagia after surgery. Postoperative cerebrospinal fluid (CSF) leakage, infection, and dysphagia were recorded in both groups. An independent t-test was used to compare quantitative variables, a chi-square test was used to compare qualitative data between the two groups. To eliminate the influence of confounding factors, logistic regression was performed for multifactor regression of factors. The results were regarded as significant when the P-values were less than 0.05 in this study.

RESULTS

In total, the non-dysphagia group comprised 70 patients and the dysphagia group comprised 190 patients, with an average age of 58.33 ± 4.68 years (ranging, 42-82 years). These patients were followed up for 28.5 ± 3.5 months (range, 24-32 months). For clinical outcomes, both groups demonstrated significant improvement in the NDI and JOA scores (P < 0.001). According to the Bazaz dysphagia grading system, mild, moderate, and severe dysphagia were found in 50, 17, and 3 patients, respectively. In total, 37.1% (n = 26) had resolved by 3 month, 38.6% (n = 27) by 6 months, and 17.1% (n = 12) by 12 months. Chi-square test results indicated that number of operated levels, operation time dT1 slope, dO-C₂ angle, dC_2-7 angle, segmental angle and dPSTT were associated with a high incidence of dysphagia. Multivariate logistic regression analysis showed that number of operated levels, operation time, dC_2-7 angle and dPSTT were significantly associated with postoperative dysphagia.

CONCLUSIONS

More operated levels, more operation time, more dC_2-7 angle and dPSTT were the risk factors for postoperative dysphagia. In additional, sufficient preoperative preparation, evaluation combined with proficient and precise surgical treatment were suggested to reduce the incidence of postoperative dysphagia when ACDF was performed.

Does Local Steroid Reduce Dysphagia After Cervical Disc Replacement? A Prospective, Randomized, Placebo-controlled, Double-blinded Study

STUDY DESIGN

A prospective, randomized, placebo-controlled, double-blinded study.

OBJECTIVE

To examine the effect of intraoperatively administered local Depo-Medrol on the incidence and severity of postoperative dysphagia in patients undergoing cervical disk replacement (CDR) surgery.

SUMMARY OF BACKGROUND DATA

Dysphagia is often reported as an adverse event after anterior cervical surgeries. One method for reducing the incidence of postoperative dysphagia in patients undergoing anterior cervical discectomy and fusion surgeries is the intraoperative application of topical corticosteroids to the retroesophageal space. There have been no studies examining the effect of local steroids on dysphagia after CDR surgery.

MATERIALS AND METHODS

Seventy-three patients underwent CDR surgery by a single surgeon at a single institution. A 1 cm ×3 cm ×3 mm gel foam collagen sponge was saturated by the nurse with either saline (1 cc) or Depo-Medrol (40 mg/1 cc) based on randomization protocol. The sponge was placed ventral to the cervical disk implant in the retroesophageal space. Study follow-up occurred on postoperative day 1, 4, 7, 14 and postoperative month 1, 2, and 3. Dysphagia outcomes were classified using the Bazaz Dysphagia Score and Eating Assessment Tool 10.

RESULTS

The steroid group, compared with the control group, had significantly reduced incidence of dysphagia (50% vs. 75%; P=0.0427) and severe dysphagia (12% vs. 36% Bazaz score, P=0.0253; 18% vs. 42% Eating Assessment Tool 10, P=0.0378) at POD4. There was no significant long-term difference in rates of dysphagia between the control and the steroid group.

CONCLUSIONS

This study provides level 1 evidence that the use of intraoperative locally administered Depo-Medrol significantly reduces the incidence and severity of dysphagia within the first week after CDR surgery. The use of local steroid may provide patients undergoing CDR surgery with a more pleasant early recovery experience with respect to dysphagia.

A Potentially Advantageous Use of a Zero-Profile, Stand-Alone Anterior Interbody Spacer at C2-3 for the Treatment of Hangman's Fracture: A Technical Case Report

Hangman’s fracture or traumatic spondylolisthesis of the axis is a common fracture pattern in the cervical spine. Nonoperative management with an external orthosis is appropriate in select cases. However, when surgery is necessary, both anterior and posterior approaches can be used, and the optimal approach has not been established. Anterior discectomy and fusion with plating at C2-3 may cause dysphagia from plate prominence, while the posterior fusion of C1-3 eliminates motion of an otherwise healthy atlantoaxial joint, resulting in a significant loss of cervical range of motion. We describe the first published application of a stand-alone, zero-profile implant at the C2-3 segment to treat Hangman’s fracture, a technique already successfully used in the C3-7 region for trauma and degenerative applications. A stand-alone, zero profile interbody spacer was employed in anterior C2-3 arthrodesis surgery for Hangman’s fracture in a 61-year-old female following failure of healing after three months in a hard cervical collar. Late postoperative imaging showed successful fusion and the patient had favorable clinical results with relief of neck pain. A zero-profile, stand-alone implant at C2/3 is an attractive option to surgically treat C2 Hangman’s fracture, potentially minimizing dysphagia attributable to an anterior plate and spare the atlantoaxial joint that is fused with C1-3 posterior arthrodesis. The benefits of the application of this technique may be validated with additional studies.

Esophagopharyngeal perforation and prevertebral abscess after anterior cervical discectomy and fusion: a case report

Anterior cervical discectomy and fusion (ACDF) represents one of the most commonly performed spine surgeries. Dysphagia secondary to esophageal injury during retraction is one of the most common complications, and usually leads to self-limiting dysphagia. However, actual perforation and violation of the esophageal tissue is much rarer and can lead to delayed deep infections. Prevertebral abscess' are one of the most feared complications after ACDF, as they can lead to severe tissue swelling, osteomyelitis, hardware failure, and even death. Due to their rarity, a gold standard of workup and treatment is still unknown. A healthy 47-year-old female presents 9 months after a C4-C7 ACDF done at an outside institution with a large prevertebral abscess, osteomyelitis, hardware failure, and pseudoarthrosis secondary to esophagopharyngeal defect and prominent hardware. Overall, the patient underwent eight surgeries, and required an extended course of intravenous (IV) antibiotics, multiple diagnostic procedures, and complex soft tissue coverage using an anterolateral thigh free flap. Currently, the patient is doing well 6 months from her last procedure without any complications or plan for future surgery. This was an extremely rare case of a late occurring prevertebral abscess after ACDF. Dysphagia in the late postoperative setting should be evaluated carefully and thoroughly for any esophageal perforation and deep infection. As exemplified in this case, even partial thickness injuries to the esophageal-pharyngeal anatomy due to hardware irrigation can lead to catastrophic complications over time. Safe removal of all hardware anteriorly to avoid continued irritation of the esophagopharyngeal mucosa should be prioritized. If anterior hardware is necessary for stability, implants with the smallest footprint should be utilized. Early collaboration with ENT colleagues should be a priority and can provide crucial diagnostic and therapeutic interventions. Complex closure with a free flap was shown to be an effective way to provide successful definitive soft tissue coverage.

The effect of local intraoperative corticosteroid application on postoperative dysphagia following anterior cervical spine surgery

Dysphagia is a common complication following anterior cervical spine surgery (ACSS). Although several literatures have reported the potential benefit of local corticosteroid application on dysphagia, its safety and efficacy are still unclear. A systematic review was performed aiming to evaluate the evidence of local corticosteroid application in prevention or treatment of postoperative dysphagia following ACSS. A systematic search was performed in September 2018 in PubMed and Embase database. The following information was extracted: study investigator, year of publication, number of patients, study design, inclusion/exclusion criteria, administration protocol of steroid, type of surgical procedure, number of levels performed, assessment methodology of dysphagia, radiologic assessment of prevertebral soft tissue swelling (PSTS), follow-up time points, outcome of dysphagia, and corticosteroid-related complications. Qualitative synthesis was performed. Finally, 5 studies met the inclusion/exclusion criteria. Four studies found that local corticosteroid application could decrease the incidence and magnitude of postoperative dysphagia while 1 study showed no effect on dysphagia significantly at 6 weeks and 3 months follow-up time. A total of 2325 patients received local corticosteroid intraoperatively; no early corticosteroid-related complication was reported. Totally, 4 adverse events occurred in long-term follow-up time, including 2 bone nonunion at 1.5 and 2.5 years postoperatively, 2 esophageal perforation at 2 months and 11 months of follow-up, respectively. Local corticosteroid application can reduce the incidence and severity of dysphagia following ACSS without increasing early corticosteroid-related complications. But further high-quality study is necessary to analyze potential delayed complications.

Comparison of Patient-Reported Postoperative Dysphagia in Patients Undergoing One-Level Versus Two-Level Anterior Cervical Discectomy and Fusion with the Zero-P Implant System

To investigate whether dysphagia differs between one-level and two-level anterior cervical discectomy and fusion (ACDF) with the Zero Profile (Zero-P) Implant System. A retrospective analysis of 208 patients who underwent ACDF with the Zero-P Implant System and had at least one year of follow-up was performed from January 2013 to December 2018. The patients were divided into two groups based on the number of operated levels (one-level group, N = 86; two-level group, N = 122). Dysphagia was assessed based on the Bazaz grading system. The incidence of dysphagia and the severity of dysphagia at each follow-up were compared between the two groups. The patients were divided into two groups (nondysphagia group, N = 160; dysphagia group, N = 48), and covariates were obtained for multivariate analysis, including demographic parameters, surgical parameters, and radiographic parameters. The results showed that the incidence and severity of postoperative dysphagia in the two-level group were significantly greater at 1 week, 1 month and 3 months postoperatively than those in the one-level group. The results of ordinal logistic regression showed that older age, two-level surgery, greater prevertebral soft tissue swelling (PSTS) and the difference between the postoperative and preoperative C_2-7 angle (dC_2-7A) were significantly associated with a higher incidence of dysphagia after ACDF with the Zero-P. Two-level ACDF with the Zero-P can result in a significantly greater incidence and severity of transient postoperative dysphagia. Older age, greater PSTS and the dC_2-7A were also associated with postoperative dysphagia after ACDF with the Zero-P.

Local Retropharyngeal Space Anesthetic for Dysphagia Reduction after Anterior Cervical Discectomy and Fusion Surgery: A Single-Center, Prospective, Randomized, Double-Blinded, Placebo-Controlled Clinical Trial

OBJECTIVE

The main objective of this study was to analyze the ability of local anesthetic instillation into the retropharyngeal space to reduce dysphagia symptoms and occurrence rates in patients undergoing anterior cervical discectomy and fusion (ACDF) procedures.

METHODS

A single-center, prospective, randomized, double-blinded, and placebo-controlled clinical study was performed. We enrolled patients undergoing one- or two-level ACDF procedures for cervical degenerative disc disease with disc herniation, radiculopathy and/or myelopathy symptoms. The patients were randomly assigned (1:1 ratio) to receive either 0.5% bupivacaine hydrochloride or 0.9% NaCl solution.

RESULTS

Forty-three (74%) and 41 (77%) of patients reported dysphagia symptoms at the time of discharge in the investigational and control groups, respectively. There were no statistically significant differences in duration of dysphagia symptoms, Swallowing-Quality of Life (SWAL-QOL) survey or pain scores between the investigational and control patient groups at any of the follow-up time points. Controlling for independent variables, only younger age significantly predicted dysphagia symptoms at discharge, 2-week, and 3-month follow-ups (P ≤ 0.03; R ≥ -0.038; OR 0.96, 95% CI 0.93-0.99. Female sex was associated with lower SWAL-QOL scores at discharge (P = 0.046; R = 0.87; OR 2.38, 95% CI 1.02-5.56). A total of 8 (13.8%) and 6 (11.3%) patients in the investigational and control groups, respectively, were referred to a specialist or underwent speech therapy for their dysphagia symptoms. There were no adverse reactions to the study drug observed.

CONCLUSIONS

Local retropharyngeal space anesthetic instillation did not reduce dysphagia symptoms or occurrence rates in patients undergoing anterior discectomy and fusion surgeries.

Improved Dysphagia Outcomes in Anchored Spacers Versus Plate-Screw Systems in Anterior Cervical Discectomy and Fusion: A Systematic Review

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To perform a systematic review of clinical outcomes between stand-alone anchored spacers and traditional cages with plate fixation for dysphagia and pseudoarthrosis using data from clinical trials.

METHODS

Our search protocol was added to PROSPERO register and systematic review using PRISMA method was performed. Then, we systematically searched for studies addressing stand-alone anchored spacers in patients who underwent ACDF. Mean Neck Disability Index (NDI), dysphagia incidence % (Dinc%), and Swallowing-Quality of Life (SQOL) scores during preoperative, immediate postoperative and last follow-up visits were extracted. Chi-square and analysis of variance (ANOVA) tests were used for statistical comparisons (P ≤ .05).

RESULTS

The initial search generated 506 articles in CENTRAL and 40 articles in MEDLINE. Finally, 14 articles were included. Total number of patients was 1173 (583 anchored stand-alone and 590 plate). Dinc% scores were statistically significantly lower in the stand-alone anchored spacer compared to the plate-screw construct (P ≤ .05). ANOVA showed no statistically significant difference in the comparisons of SQOL. On the other hand, NDI scores were statistically significantly lower in baseline of stand-alone anchored spacer and the plate-screw construct compared with both immediate postoperative and last follow-up visits (P ≤ .05).

CONCLUSIONS

Our study results revealed that the stand-alone anchored spacers were associated with less dysphagia in the immediate and last follow-up.

Outcomes After Cervical Disc Arthroplasty Versus Stand-Alone Anterior Cervical Discectomy and Fusion: A Meta-Analysis

STUDY DESIGN

Systemic review and meta-analysis.

OBJECTIVES

To review and compare surgical outcomes for patients undergoing stand-alone anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty (CDA) for the treatment of cervical spine disease.

METHODS

A systematic search was performed on PubMed, Medline, and the Cochrane Library. Comparative trials measuring outcomes of patients undergoing CDA and stand-alone ACDF for degenerative spine disease in the last 10 years were selected for inclusion. After data extraction and quality assessment, statistical analysis was performed with R software metafor package. The random-effects model was used if there was heterogeneity between studies; otherwise, the fixed-effects model was used.

RESULTS

In total, 12 studies including 859 patients were selected for inclusion in the meta-analysis. Patients undergoing stand-alone ACDF had a statistically significant increase in postoperative segmental angles (mean difference 0.85° [95% confidence interval = 0.35° to 1.35°], P = .0008). Patients undergoing CDA had a decreased rate of developing adjacent segmental degeneration (risk ratio = 0.56 [95% confidence interval = -0.06 to 1.18], P = .0745). Neck Disability Index, Japanese Orthopedic Association score, Visual Analogue Scale of the arm and neck, as well as postoperative cervical angles were similar between the 2 treatments.

CONCLUSIONS

When compared with CDA, stand-alone ACDF offers similar clinical outcomes for patients and leads to increased postoperative segmental angles. We encourage further blinded randomized trials to compare rates of adjacent segmental degeneration and other postoperative outcomes between these 2 treatments options.

The effect of the difference in C2-7 angle on the occurrence of dysphagia after anterior cervical discectomy and fusion with the zero-P implant system

OBJECTIVES

To investigate the effect of the difference in C2-7 angle on dysphagia after anterior cervical discectomy and fusion (ACDF) with the Zero-P Implant System.

METHODS

A retrospective analysis of 181 patients who underwent ACDF with the Zero-P Implant System and had at least one year of follow-up from January 2011 to November 2018 was performed. All patients were divided into a non-dysphagia group and a dysphagia group to explore the effect of the difference between postoperative and preoperative C2-7 angle (dC2-7A) on postoperative dysphagia. At the same time, other possible related factors including the difference between postoperative and preoperative O-C2 angle (dO-C2A), sex, age, body mass index (BMI), intraoperative time, estimated blood loss, diabetes mellitus, hypertension, smoking, alcohol consumption, prevertebral soft-tissue swelling (PSTS), the highest segment involved in the surgery and the levels of surgery segments were analyzed.

RESULTS

In total, the non-dysphagia group comprised 139 patients and the dysphagia group comprised 42 patients. The single-factor analysis showed that smoking, PSTS and dC2-7A were significantly different between the two groups (P < 0.05). Spearman's correlation coefficient showed no significant correlation between the degree of dysphagia and dC2-7A (P > 0.05). The results of the multiple-factor analysis with an ordinal logistic regression model showed that smoking, PSTS and dC2-7A were significantly associated with the incidence of dysphagia (P < 0.05).

CONCLUSIONS

The postoperative C2-7 angle has an important effect on the occurrence of dysphagia in patients undergoing Zero-P implant system interbody fusion surgery.

Zero-profile versus cage-plate interbody fusion system in anterior cervical discectomy and fusion for the treatment of multilevel cervical spondylosis: A protocol of systematic review and meta-analysis

BACKGROUND

The objective of this meta-analysis was to summarize and identify the available evidence from these studies to estimate which device was better for multilevel cervical spondylotic myelopathy (MCSM). And provides clinicians with evidence on which to base their clinical decision making.

METHODS

This review will include all studies comparing the new Zero-profile versus cage-plate interbody fusion system in anterior cervical discectomy and fusion (ACDF) for the treatment of MCSM. The search strategy will be performed in 9 databases. We will not establish any limitations to language and publication status, published from inception to the July, 2020. Two reviewers will screen, select studies, extract data, and assess quality independently. Outcome is operative time, blood loss, clinical function outcome, radiologic outcomes, and complications. The methodological quality including the risk of bias of the included studies will be evaluated. We will carry out statistical analysis using RevMan 5.3 software.

RESULTS

This study will summarize current evidence to assess the efficacy and safety of Zero-profile versus cage-plate interbody fusion system in ACDF for the treatment of MCSM.

CONCLUSION

The findings of this study will provide helpful evidence for the clinician, and will promote further studies, as well as comparing the 2 devices in ACDF for MCSM REGISTRATION NUMBER:: INPLASY202070095 (DOI number: 10.37766/inplasy2020.7.0095).

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

PURPOSE

To evaluate the efficacy of locking stand-alone cage (LSC) compared with anterior plate construct (APC) in anterior cervical discectomy and fusion (ACDF).

METHODS

A comprehensive literature search was carried out in PubMed, Embase, Web of Science, and Cochrane Library to screen randomized controlled trials (RCTs) that directly compared LSC with APC in ACDF. The Cochrane Collaboration's tool was used for assessment of study quality. Data were analyzed with the Review Manager 5.3 software.

RESULTS

A total of seven RCTs were included. The results revealed no significant differences between LSC and APC in ACDF regarding the fusion rate, Japanese Orthopaedic Association score, visual analogue scale score, neck disability index score, hospital stay, subsidence rate, cervical lordosis, segmental Cobb angle, and disc height. However, LSC was associated with a significantly shorter operation time, less blood loss, lower overall incidence of dysphagia, and lower adjacent-level ossification (ALO) rate compared with APC.

CONCLUSION

In summary, LSC is not only a safe and effective device for ACDF but also has the advantages of significantly reduced operation time, blood loss, overall incidence of dysphagia, and ALO rate over APC. Therefore, LSC is a better alternative than APC for the patients undergoing ACDF procedures.

Effectiveness of cervical zero profile integrated cage with and without supplemental posterior Interfacet stabilization

BACKGROUND

Conditions requiring cervical decompression and stabilization are commonly treated using anterior cervical discectomy and fusion using an anterior cage-plate construct. Anterior zero profile integrated cages are an alternative to a cage-plate construct, but literature suggests they may result in less motion reduction. Interfacet cages may improve integrated cage stability. This study evaluated the motion reduction of integrated cages with and without supplemental interfacet fixation. Motion reduction of integrated cages were also compared to published cage-plate results.

METHODS

Seven cadaveric (C2-T1) spines were tested in flexion-extension, lateral bending, and rotation. Specimens were tested: 1) intact, 2) C6-C7 integrated cage, 3) C6-C7 integrated cage + interfacet cages, 4) additional integrated cages at C3-C4 and C4-C5, 5) C3-C4, C4-C5 and C6-C7 integrated cages + interfacet cages. Motion, lordosis, disc and neuroforaminal height were assessed.

FINDINGS

Integrated cage at C6-C7 decreased flexion-extension by 37% (P = .06) and C3-C5 by 54% (P < .01). Integrated + interfacet cages decreased motion by 89% and 86% compared to intact (P < .05). Integrated cages increased lordosis at C4-C5 and C6-C7 (P < .01). Integrated + interfacet cages returned C3-C5 lordosis to intact values, while C6-C7 remained more lordotic (P = .02). Compared to intact, neuroforaminal height increased after integrated cages at C3-C5 (P ≤ .01) and at all levels after interfacet cages (P < .01).

INTERPRETATION

Anterior integrated cages provides less stability than traditional cage-plate constructs while supplemental interfacet cages improve stabilization. Integrated cages provide more lordosis at caudal levels and increase neuroforaminal height more at cranial levels. After interfacet cages, posterior disc height and neuroforaminal height increased more at the caudal segments.