The results of anterior interbody fusion of the cervical spine. Review of ninety-three consecutive cases

Clinicosocial determinants of hospital stay following cervical decompression: A public healthcare perspective and machine learning model

OBJECTIVE

Post-operative length of hospital stay (LOS) is a valuable measure for monitoring quality of care provision, patient recovery, and guiding hospital resource management. But the impact of patient ethnicity, socio-economic deprivation as measured by the indices of multiple deprivation (IMD), and pre-existing health conditions on LOS post-anterior cervical decompression and fusion (ACDF) is under-researched in public healthcare settings.

METHODS

From 2013 to 2023, a retrospective study at a single center reviewed all ACDF procedures. We analyzed 14 non-clinical predictors-including demographics, comorbidities, and socio-economic status-to forecast a categorized LOS: short (≤2 days), medium (2-3 days), or long (>3 days). Three machine learning (ML) models were developed and assessed for their prediction reliability.

RESULTS

2033 ACDF patients were analyzed; 79.44 % had a LOS ≤ 2 days. Significant predictors of LOS included patient sex (HR:0.81[0.74-0.88], p < 0.005), IMD decile (HR:1.38[1.24-1.53], p < 0.005), smoking (HR:1.24[1.12-1.38], p < 0.005), DM (HR:0.70[0.59-0.84], p < 0.005), and COPD (HR:0.66, p = 0.01). Asian patients had the highest mean LOS (p = 0.003). Testing on 407 patients, the XGBoost model achieved 80.95 % accuracy, 71.52 % sensitivity, 85.76 % specificity, 71.52 % positive predictive value, and a micro F1 score of 0.715. This model is available at: https://acdflos.streamlit.app.

CONCLUSIONS

Utilizing non-clinical pre-operative parameters such as patient ethnicity, socio-economic deprivation index, and baseline comorbidities, our ML model effectively predicts postoperative LOS for patient undergoing ACDF surgeries. Yet, as the healthcare landscape evolves, such tools will require further refinement to integrate peri and post-operative variables, ensuring a holistic decision support tool.

The Positive Side Effect of Anterior Cervical Decompression and Fusion on Axial Neck Pain

STUDY DESIGN

Observational Cohort Study.

OBJECTIVES

This study aims to comprehensively assess the outcomes of anterior cervical spine surgery in patients who have undergone surgical intervention for radiculopathy or myelopathy, with a specific focus on the surgery's impact on axial neck pain.

METHODS

Data from an institutional spine surgery registry were analyzed for patients who underwent anterior cervical spine surgery between January 2016 and March 2022. Patient demographics, clinical variables, and outcome measures, including the Neck Disability Index (NDI), numeric rating scales for neck and arm pain (NRS-Neck and NRS-Arm), and 36-Item Short Form Health Survey (SF-36) scores, were collected. Statistical analysis included paired t-tests, chi-squared tests, and multivariate linear regression.

RESULTS

Of 257 patients, 156 met the inclusion criteria. Patients showed significant improvement in NDI, NRS-Neck, NRS-Arm, SF-36 (Physical and Mental components), and all changes exceeded the minimum clinically important difference. Multivariate regression revealed that lower preoperative physical and mental component scores and higher preoperative NRS-Neck predicted worse NDI scores at follow-up.

CONCLUSIONS

This study underscores that anterior cervical fusion not only effectively alleviates arm pain and disability but also has a positive impact on axial neck pain, which may not be the primary target of surgery. Our findings emphasize the potential benefits of surgical intervention when neck pain coexists with neurologic compression. This contribution adds to the growing body of evidence emphasizing the importance of precise diagnosis and patient selection. Future research, ideally focusing on patients with isolated neck pain, should further explore alternative surgical approaches to enhance treatment options.

The Impact of Posterior Intervertebral Osteophytes on Patient-Reported Outcome Measures After L5-S1 Anterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

(1) To develop a reliable grading system to assess the severity of posterior intervertebral osteophytes and (2) to investigate the impact of posterior intervertebral osteophytes on clinical outcomes after L5-S1 decompression and fusion through anterior lumbar interbody fusion (ALIF) and minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF).

BACKGROUND

There is limited evidence regarding the clinical implications of posterior lumbar vertebral body osteophytes for ALIF and MIS-TLIF surgeries and there are no established grading systems that define the severity of these posterior lumbar intervertebral osteophytes.

PATIENTS AND METHODS

A retrospective analysis of patients undergoing L5-S1 ALIF or MIS-TLIF was performed. Preoperative and postoperative patient-reported outcome measures of the Oswestry Disability Index (ODI) and leg Visual Analog Scale (VAS) at 2-week, 6-week, 12-week, and 6-month follow-up time points were assessed. Minimal clinically important difference (MCID) for ODI of 14.9 and VAS leg of 2.8 were utilized. Osteophyte grade was based on the ratio of osteophyte length to foraminal width. "High-grade" osteophytes were defined as a maximal osteophyte length >50% of the total foraminal width.

RESULTS

A total of 70 consecutive patients (32 ALIF and 38 MIS-TLIF) were included in the study. There were no significant differences between the two cohorts in patient-reported outcome measures or achievement of MCID for Leg VAS or ODI preoperatively or at any follow-ups. On multivariate analysis, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with leg VAS or ODI scores at any follow-up time point. In addition, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with the achievement of MCID for leg VAS or ODI at 6 months.

CONCLUSION

ALIF and MIS-TLIF are both valid options for treating degenerative spine conditions and lumbar radiculopathy, even in the presence of high-grade osteophytes that significantly occupy the intervertebral foramen.

LEVEL OF EVIDENCE

3.

Longer Screws Decrease the Risk of Radiographic Pseudarthrosis Following Elective Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

In patients undergoing elective anterior cervical discectomy and fusion (ACDF), we sought to determine the impact of screw length on: (1) radiographic pseudarthrosis, (2) pseudarthrosis requiring reoperation, and (3) patient-reported outcome measures (PROMs).

METHODS

A single-institution, retrospective cohort study was undertaken from 2010-21. The primary independent variables were: screw length (mm), screw length divided by the anterior-posterior vertebral body diameter (VB%), and the presence of any screw with VB% < 75% vs all screws with VB% ≥ 75%. Multivariable logistic regression controlled for age, BMI, gender, smoking, American Society of Anesthesiology grade, number of levels fused, and whether a corpectomy was performed.

RESULTS

Of 406 patients undergoing ACDF, levels fused were: 1-level (39.4%), 2-level (42.9%), 3-level (16.7%), and 4-level (1.0%). Mean screw length was 14.3 ± 2.3 mm, and mean VB% was 74.4 ± 11.2. A total of 293 (72.1%) had at least one screw with VB% < 75%, 113 (27.8%) had all screws with VB% ≥ 75%, and 141 (34.7%) patients had radiographic pseudarthrosis at 1-year. Patients who had any screw with VB% < 75% had a higher rate of radiographic pseudarthrosis compared to those had all screws with VB% ≥ 75% (39.6% vs 22.1%, P < .001). Multivariable logistic regression revealed that a higher VB% (OR = .97, 95%CI = .95-.99, P = .035) and having all screws with VB% ≥ 75% (OR = .51, 95%CI = .27-.95, P = .037) significantly decreased the odds of pseudarthrosis at 1-year, with no difference in reoperation or PROMs (all P > .05).

CONCLUSION

Longer screws taking up ≥75% of the vertebral body protected against radiographic pseudarthrosis at 1-year. Maximizing screw length in ACDF is an easily modifiable factor directly under the surgeon's control that may mitigate the risk of pseudarthrosis.

Cervical sagittal balance: a predictor of neck pain after anterior cervical spine surgery?

PURPOSE

To determine the possible relation between cervical sagittal balance and neck pain in patients having anterior cervical spine (ACS) surgery.

MATERIALS AND METHODS

Retrospective monocentric study on 85 patients who underwent ACS surgery between 2014 and 2016. Clinically, all patients were assessed using the Neck Disability Index (NDI). Radiological assessment was achieved by MRI or CT-scan of the cervical spine allowing measurement of radiological parameters for preoperative cervical sagittal balance. These same criteria were measured postoperatively using X-rays.

RESULTS

There is a statistically significant increase in the Cobb angle postoperatively (10.34 degrees) compared to preoperatively (6.68 degrees) (p < 0.05). Concomitantly, there is a statistically significant decrease in NDI postoperatively (22.69%) compared to preoperatively (42.31%) (p < 0.01). There is a negative correlation between Cobb angle and NDI (r= -0.31) (p < 0.05).

CONCLUSION

An improvement in the cervical sagittal balance after ACS surgery is accompanied by a reduction of neck pain. Radiological parameters of cervical sagittal balance may be taken into account when planning surgery in order to maintain cervical alignment and thereby limit the occurrence of neck pain.

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.

What is the role of dynamic cervical spine radiographs in predicting pseudarthrosis revision following anterior cervical discectomy and fusion?

BACKGROUND CONTEXT

Postoperative dynamic radiographs are used to assess fusion status after anterior cervical discectomy and fusion (ACDF) with comparable accuracy to computed tomography (CT) scans.

PURPOSE

To (1) determine if dynamic radiographs accurately predict pseudarthrosis revision in a cohort of largely asymptomatic patients who underwent ACDF, (2) determine how adjacent segment motion is affected by fusion status, and (3) analyze how clinical outcomes differ between patients with symptomatic and asymptomatic pseudarthrosis.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Patients ≥ 18 years who underwent primary one- to four-level ACDF at a single institution over a 10-year period.

OUTCOME MEASURES

Interspinous motion on preoperative and postoperative flexion-extension radiographs and preoperative and postoperative Visual Analogue Scale for Neck Pain (VAS Neck) and Arm Pain (VAS Arm), Neck Disability Index (NDI), Modified Japanese Orthopaedic Association scale (mJOA), Mental and Physical Component Scores of the Short-Form 12 (SF-12) Health Survey (MCS-12 and PCS-12) METHODS: The difference in spinous process motion between flexion and extension radiographs was used to determine motion at each level of the ACDF construct. Pseudarthrosis was defined as ≥ 1 mm spinous process motion on dynamic radiographs. A receiver operating characteristic (ROC) curve was generated to predict the probability of surgical revision for pseudarthrosis based on millimeters of interspinous motion at each instrumented level. Patient reported outcome measures (PROMs) were used to assess the effect of pseudarthrosis on clinical outcomes. Alpha was set at p<.05.

RESULTS

A total of 597 patients met inclusion criteria including 1,203 ACDF levels. Of those, 215 patients (36.0%) were diagnosed with a pseudarthrosis on dynamic radiographs with 29 patients (4.9%) requiring pseudarthrosis revision. ROC analysis identified a "cutoff" value of 1.00 mm of interspinous process motion for generating an optimal area under the curve (AUC). The negative predictive value (NPV) was 99.6%, whereas the positive predictive value (PPV) was 13.7%. When analyzing adjacent segment motion, the Δ supra-adjacent interspinous process motion (ISM) was significantly lower for patients with a superior construct pseudarthrosis (-1.06 mm vs. 1.80 mm, p<.001), whereas the Δ infra-adjacent level ISM was significantly lower for patients with an inferior construct pseudarthrosis (-1.21 mm vs. 2.15 mm, p<.001). Patients with a pseudarthrosis not requiring revision had worse postoperative NDI (29.3 vs. 23.4, p=.027), VAS Neck (3.40 vs. 2.63, p=.012), and VAS Arm (3.09 vs. 1.85, p=.001) scores at 3 months, but not 1-year, compared with patients who were fused. Patients requiring pseudarthrosis revision had higher 1-year postoperative NDI (38.0 vs. 23.7, p=.047) and lower 1-year postoperative Δ VAS Arm (-0.22 vs. -2.97, p=.016) scores.

CONCLUSIONS

One-year postoperative dynamic radiographs have a greater than 99% negative predictive value for identifying patients requiring pseudarthrosis revision, but they have a low positive predictive value. Most patients with a pseudarthrosis remain asymptomatic with similar 1-year postoperative patient-reported outcomes compared with patients without a pseudarthrosis.

Assessing Postoperative Pseudarthrosis in Anterior Cervical Discectomy and Fusion (ACDF) on Dynamic Radiographs Using Novel Angular Measurements

STUDY DESIGN

A retrospective review of operative patients at a single institution.

OBJECTIVE

The aim was to validate a novel method of detecting pseudarthrosis on dynamic radiographs.

SUMMARY OF BACKGROUND DATA

A common complication after anterior cervical discectomy and fusion is pseudarthrosis. A previously published method for detecting pseudarthrosis identifies a 1 mm difference in interspinous motion (ISM), which requires calibration of images and relies on anatomic landmarks difficult to visualize. An alternative is to use angles between spinous processes, which does not require calibration and relies on more visible landmarks.

MATERIALS AND METHODS

ISM was measured on dynamic radiographs using the previously published linear method and new angular method. Angles were defined by lines from screw heads to dorsal points of spinous processes. Angular cutoff for fusion was calculated using a regression equation correlating linear and angular measures, based on the 1 mm linear cutoff. Pseudarthrosis was assessed with both cutoffs. Sensitivity, specificity, inter-reliability and intrareliability of angular and linear measures used postoperative computed tomography (CT) as the reference.

RESULTS

A total of 242 fused levels (81 allograft, 84 polyetheretherketone, 40 titanium, 37 standalone cages) were measured in 143 patients (mean age 52.0±11.5, 42%F). 36 patients (66 levels) had 1-year postoperative CTs; 13 patients (13 levels) had confirmed pseudarthrosis. Linear and angular measurements closely correlated ( R =0.872), with 2.3° corresponding to 1 mm linear ISM. Potential pseudarthroses was found in 28.0% and 18.5% levels using linear and angular cutoffs, respectively. Linear cutoff had 85% sensitivity, 87% specificity; angular cutoff had 85% sensitivity, 96% specificity for detecting CT-validated pseudarthrosis. Interclass correlation coefficients were 0.974 and 0.986 (both P <0.001); intrarater reliability averaged 0.953 and 0.974 ( P <0.001 for all) for linear and angular methods, respectively.

CONCLUSIONS

The angular measure for assessing potential pseudarthrosis is as sensitive as and more specific than published linear methods, has high interobserver reliability, and can be used without image calibration.

LEVEL OF EVIDENCE

3.

Partial uncinatectomy combined with anterior cervical discectomy and fusion for the treatment of one-level cervical radiculopathy: analysis of clinical efficacy and sagittal alignment

BACKGROUND

Biomechanical studies have demonstrated that uncovertebral joint contributes to segment mobility and stability to a certain extent. Simultaneously, osteophytes arising from the uncinate process are a common cause of cervical spondylotic radiculopathy (CSR). For such patients, partial uncinatectomy (UT) may be required. However, the clinical efficacy and sagittal alignment of partial UT during anterior cervical discectomy and fusion (ACDF) have not been fully elucidated.

METHODS

A total of 87 patients who had undergone single level ACDF using a zero-profile device from July 2014 to December 2018 were included. Based on whether the foraminal part of the uncovertebral joint was resected or preserved, the patients were divided into the ACDF with UT group (n = 37) and the ACDF without UT group (n = 50). Perioperative data, radiographic parameters, clinical outcomes, and complications were compared between the two groups.

RESULTS

The mean follow-up was 16.86 ± 5.63 and 18.36 ± 7.51 months in the ACDF with UT group and ACDF without UT group, respectively (p > 0.05). The average preoperative VAS arm score was 5.89 ± 1.00 in the ACDF with UT group and 5.18 ± 1.21 in the ACDF without UT group (p = 0.038). However, the average VAS arm score was 4.22 ± 0.64, 4.06 ± 1.13 and 1.68 ± 0.71, 1.60 ± 0.70 at 1 week post operation and at final follow up, respectively, (p > 0.05). We also found that the C2-7 SVA and St-SVA at the last follow-up and their change (last follow-up value - preoperative value) in the ACDF with UT group were significantly higher than ACDF without UT group (p < 0.05). No marked differences in the other cervical sagittal parameters, fusion rate or complications, including dysphagia, ASD, and subsidence, were observed.

CONCLUSIONS

Our result indicates that ACDF using a zero-p implant with or without partial UT both provide satisfactory clinical efficacy and acceptable safety. However, additional partial UT may has a negative effect on cervical sagittal alignment.

Does the Predominant Pain Location Influence Functional Outcomes, Satisfaction and Return to Work After Anterior Cervical Discectomy and Fusion for Cervical Radiculopathy?

STUDY DESIGN

Retrospective review of prospectively-collected registry data.

OBJECTIVES

The aim of this study was to determine how different combinations of preoperative neck pain (NP) and arm pain (AP) influence functional outcomes, patient satisfaction, and return-to-work in patients undergoing anterior cervical discectomy and fusion (ACDF) for degenerative cervical radiculopathy (DCR).

SUMMARY OF BACKGROUND DATA

Surgeons often base decisions on the traditional belief that the predominance of radicular upper extremity symptoms is a stronger indication for cervical spine surgery than axial pain. However, there is a paucity of literature supporting this notion.

METHODS

A prospectively maintained registry was reviewed for all patients who underwent primary ACDF for DCR. Patients were categorized into three groups depending on predominant pain location: AP predominant ([APP]; AP > NP), NP predominant ([NPP]; NP > AP), and equal pain predominance ([EPP]; NP = AP). Patients were prospectively followed for at least 2 years.

RESULTS

In total, 303 patients were included: 27.4% APP, 38.9% NPP, and 33.7% EPP cases. The APP group was significantly older (P = 0.030), although there were no other preoperative differences among the three groups. After adjusting for baseline differences, the SF-36 Physical Component Summary was significantly better in the APP group at 6 months (P = 0.048) and 2 years (P = 0.039). In addition, they showed a trend towards better 6-month Neck Disability Index (P = 0.077) and 2-year SF-36 Mental Component Summary (P = 0.059). However, an equal proportion of patients in each group achieved the Minimal Clinically Important Difference for each outcome, were satisfied, and returned to work 2 years after surgery.

CONCLUSION

Although patients with NPP had slightly poorer function and quality of life, all patients experienced a clinically meaningful improvement in patient-reported outcomes, regardless of the predominant pain location. High rates of satisfaction and return-to-work were also achieved. In the context of proper indications, these findings suggest that ACDF can be equally effective for DCR patients with varying combinations of NP or AP.Level of Evidence: 3.

Comparison of adverse events between cervical disc arthroplasty and anterior cervical discectomy and fusion: a 10-year follow-up

BACKGROUND CONTEXT

Cervical disc arthroplasty (CDA) has been advocated as an alternative to anterior cervical discectomy and fusion (ACDF) with the added potential to reduce the risk of adjacent level disc degeneration and segmental instability. However, the long-term adverse events of arthroplasty have yet to be fully reported.

PURPOSE

To investigate the 10-year follow-up adverse events rates between CDA and ACDF.

STUDY DESIGN/SETTING

The study was a randomized, prospective, multicenter Investigational Device Exemption (IDE) trial and its continued follow-up as a postapproval study (PAS). Single level surgeries were performed for cervical disc pathologies between May 2002 and October 2004.

PATIENT SAMPLE

n=463 patients.

OUTCOME MEASURES

Adverse events comparison of CDA and ACDF from self-reported and physiologic measures.

METHODS

At each evaluation time point, subjects were queried for adverse events since their last visit; and all adverse events were documented, regardless of whether or not they appeared related to the surgery or device. Adverse events were recorded, categorized, and assessed for severity and relationship to the study device and/or surgical procedure. The 10-year cumulative rates for each type of adverse events were summarized using a life-table method for the time-to-event analysis. A log-rank test was used to compare the two treatment groups.

RESULTS

A total of 242 patients received CDA and 221 patients received ACDF. At 10-year follow-up, 54% (130/242) of CDA patients and 47% (104/221) of the ACDF subjects were evaluated. At up to 10-year follow-up, 231 patients in the CDA group (cumulative rate 98.4%) and 199 patients in the ACDF group (cumulative rate 98.7%) had at least one adverse event. Overall, the difference in the cumulative rate of all adverse events over 10 years was not statistically different (p=0.166). The cumulative rates of the following adverse events were not different between the two groups for cancer, cardiovascular, death, dysphonia/dysphagia, gastrointestinal, infection, urogenital, respiratory, implant displacement/loosening, implant malposition, neck and arm pain, neurological, other pain, spinal events, and intraoperative vascular injury. However, there were more adverse events in the CDA group resulting from trauma (p=.012) and more spinal events at the index level (p=.006). The ACDF group had significantly more nonunion events (p=.019), and nonunion outcome pending (p=.034), adjacent level spinal events (p=.033), and events that fell into the "other" category (p=.015).

CONCLUSIONS

The cumulative rates of patients who had any adverse events were not different between the artificial cervical disc and the anterior cervical arthrodesis groups. In addition, the cumulative rates were not different between the two groups for the majority of categories as well.

Intraoperative Spinal Cord Monitoring Does Not Decrease New Postoperative Neurological Deficits in Patients With Cervical Radiculopathy or Spondylotic Myelopathy Undergoing One or Two Level Anterior Cervical Discectomy And Fusion

BACKGROUND

Intraoperative neurological monitoring (IONM) is commonly used in spine surgery. However, the utility of IONM in anterior cervical decompression and fusion (ACDF) remains a topic of debate. The purpose of the study was to investigate the utility and cost of IONM (both Somatosensory evoked potentials (SSEPs) and Motor Evoked Potentials (Tc-MEPs)) in reducing postoperative neurological deficits in myelopathic and non-myelopathic patients undergoing ACDF.

METHODS

Retrospective chart review was performed to include only patients with cervical radiculopathy or myelopathy undergoing one or two level ACDF over a 7-year period at a busy academic center. SSEP and Tc-MEP tracings were reviewed for all monitored patients and significant changes and inconsistencies were noted. IONM billing codes (SSEP/Tc-MEP) were reviewed and summed to evaluate the average procedural cost. Medical records were reviewed for preoperative physical exam and for new postoperative neurological deficits on postoperative day one and again at six weeks and matched to the monitored tracings.

RESULTS

There were 249 total patients (48 Non-monitored, 201 monitored). There was no difference in gender, age, or BMI between monitored and non-monitored groups. There was no difference in new neurological deficits in monitored compared with non-monitored patients with radiculopathy (p=0.1935) or myelopathy (p=0.1977). However, when radiculopathy and myelopathy patients were combined, there was an increased incidence of new neurologic deficits in monitored patients (8.0%) versus non-monitored patients (0%) (p=0.0830). All new neurological deficits occurred in patients with normal IONM tracings. There were no new neurologic deficits in the non-monitored radiculopathy or myelopathy groups. The average IONM procedure charge was $6500.

CONCLUSION

Our results indicate that intraoperative spinal cord monitoring did not reduce new neurological deficits in our cohort of patients. The higher incidence in new neurological deficits despite no IONM changes in our monitored group suggests a lack of utility of IONM in ACDF. Furthermore, at an average of $6500 per IONM procedure, the present study underlines the importance of prudence when choosing to use IONM in the era of cost containment.Level of Evidence: III.

Biomechanical Analysis of an Anterior Cervical Discectomy and Fusion Pseudarthrosis Model Revised With Machined Interfacet Allograft Spacers

STUDY DESIGN

Biomechanics study.

OBJECTIVES

To evaluate the biomechanical advantage of interfacet allograft spacers in an unstable single-level and 2-level anterior cervical discectomy and fusion (ACDF) pseudoarthrosis model.

METHODS

Nine single-level and 8 two-level ACDF constructs were tested. Range of motion in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) at 1.5 N m were collected in 4 testing configurations: (1) intact spine, (2) ACDF with interbody graft and plate/screw, (3) ACDF with interbody graft and plate/loosened screws (loose condition), and (4) ACDF with interbody graft and plate/loosened screws supplemented with interfacet allograft spacers (rescue condition).

RESULTS

All fixation configurations resulted in statistically significant decreases in range of motion in all bending planes compared with the intact spine (P < .05). One Level. Performing ACDF with interbody graft and plate on the intact spine reduced FE, LB, and AR 60.0%, 64.9%, and 72.9%, respectively. Loosening the ACDF screws decreased these reductions to 40.9%, 44.6%, and 52.1%. The addition of interfacet allograft spacers to the loose condition increased these reductions to 74.0%, 84.1%, and 82.1%. Two Level. Performing ACDF with interbody graft and plate on the intact spine reduced FE, LB, and AR 72.0%, 71.1%, and 71.2%, respectively. Loosening the ACDF screws decreased these reductions to 55.4%, 55.3%, and 51.3%. The addition of interfacet allograft spacers to the loose condition significantly increased these reductions to 82.6%, 91.2%, and 89.3% (P < .05).

CONCLUSIONS

Supplementation of a loose ACDF construct (pseudarthrosis model) with interfacet allograft spacers significantly increases stability and has potential applications in treating cervical pseudarthrosis.

Does screw length for primary two-level ACDF influence pseudarthrosis risk?

BACKGROUND CONTEXT

Pseudarthrosis remains a major complication for patients undergoing anterior cervical discectomy and fusion (ACDF; 0%-15% at 1-year follow-up). Potentially modifiable risk factors are known in literature, such as smoking and osteoporosis. Biomechanical studies suggest that plates with locking screws can enhance the fixation rigidity and pull-out strength. Although longer screws are known to be correlated with increased pull-out strength, deeper screw depths can increase the risk for intraoperative complications. An important factor that has yet to be studied is the minimum screw length relative to the diameter of the vertebral body (VB) necessary to achieve successful fusion. In this study, we hypothesize that screws with shorter depths relative to the VB will increase the risk for radiographic pseudarthrosis and result in poor patient reported outcomes (PROs).

PURPOSE

To examine the impact of ACDF screw length on pseudarthrosis risk.

STUDY DESIGN

A review of prospectively collected data.

PATIENT SAMPLE

A total of 85 patients were included in this study. The mean age ±standard deviation was 58.9±10.3 and 42.4% of patients were female. The mean follow-up was 21.6±8.3 months.

OUTCOME MEASURES

The neck disability index (NDI) was used to assess PROs up to 2-years after surgery. For each ACDF level, the screw length and VB% (screw length divided by the anterior-posterior VB diameter) were measured. Radiographic pseudarthrosis (interspinous motion [ISM] ≥1 mm) was recorded at 6-weeks, 6-months, and 1-year for each patient. The positive and negative predictive values (PPV, NPV) for ISM ≥ 1mm were measured for different VB% thresholds. A VB% of <75% was found to have the highest PPV (93%) and NPV (70%) for radiographic pseudarthrosis. This threshold of <75% was then assessed in our bivariate and multivariate analyses.

METHODS

We reviewed a database (2015-2018) of adult (≥18 years old) patients who underwent a primary two-level ACDF with or without corpectomy. All ACDF constructs involved fixed angle screws. The minimum follow-up period was 1 year. Multivariate analyses were performed to determine if screw VB% was an independent risk factor for radiographic pseudarthrosis.

RESULTS

By 1-year, overall fusion success was achieved in 92.9% of patients. The 1-year revision rate was 4.7%. Patients with any screw VB% <75% had substantially worse fusion success (64.3%) than those who did not (98.6%) at 1-year. The VB% <75% increased the risk for radiographic pseudarthrosis at every follow up period. In comparison to other time-points, patients with radiographic pseudarthrosis at 6 weeks had significantly worse NDI scores by 2-years (p=.047). The independent risk factors for radiographic pseudarthrosis at 6-weeks included any screw VB% <75% (OR 77, p<.001), prior/current smoker (OR 6.8, p=.024), and corpectomy (OR 0.1, p=.010). Patients with ISM≥1 mm had a higher rate of revision surgery at 1-year (5.9% vs. 3.9%), but this was not statistically significant (p=.656).

CONCLUSIONS

In primary two-level ACDF, VB% <75% is significantly associated with increased ISM (≥1 mm) at all time points for this study. As an intraoperative guide, spine surgeons can use the screw VB% threshold of <75% to avoid unnecessarily short screws. This threshold can be easily measured pre- and intraoperatively, and has been found to be strongly correlated to radiographic pseudarthrosis in the early postoperative period.

Characterizing the fusion order and level-specific rates of arthrodesis in 3-level anterior cervical discectomy and fusion: A radiographic study

Pseudarthrosis is a well-recognized complication following multi-level ACDF. We aim to characterize the fusion order and level-specific rates of arthrodesis across four time points following 3-level ACDF. Patients who underwent 3-level ACDF by three UCSF spine surgeons from August 2012 to December 2019 were identified. Fusion status at each level was determined by measuring the interspinous motion on flexion and extension radiographs and assessing for evidence of bridging bone. Measurements were performed post-operatively at 6 weeks, 6 months, 12 months, and 18-24 months. A total of 77 patients with 3-level ACDF were identified and included in this study. Specific ACDF levels include C3-C6 (17 patients), C4-C7 (57 patients), and C5-T1 (3 patients). At 6 months, the cranial, middle, and caudal level fusion rates were 17.0%, 34.0%, and 3.8%, respectively. By 24 months, fusion rates were 61.1%, 88.9%, and 27.8% at the cranial, middle, and caudal level, respectively. PEEK cages were associated with lower odds of multi-level arthrodesis. Arthrodesis occurred the quickest at the middle level with an 88.9% fusion rate by 24 months after surgery. The caudal level had the slowest rate of arthrodesis with only a 27.8% fusion rate at 24 months, likely due to increased biomechanical stress at the most caudal level. Allograft was associated with higher odds of multi-level arthrodesis compared to PEEK cages.

Outcomes of Revision Surgery for Pseudarthrosis After Anterior Cervical Fusion: Case Series and Systematic Review

STUDY DESIGN

Case series/systematic review.

OBJECTIVES

To report on patients undergoing posterior cervical fusion for symptomatic pseudarthrosis following anterior cervical discectomy and fusion (ACDF), and to assess outcomes reporting in the literature.

METHODS

Patients undergoing posterior instrumented fusion for pseudarthrosis after primary ACDF from 2013 to 2018 by a single surgeon were reviewed consecutively. Neck Disability Index (NDI) and visual analogue scale (VAS) arm/neck were recorded at preoperative, 6-month, and 1-year time points. A systematic review of the literature was performed, and outcomes reporting was recorded.

RESULTS

NDI scores were 54.4 (SD 19.1), 36.6 (SD 18.1), and 41.2 (SD 19.2) at preoperative, 6-month, and 1-year time points, respectively, with improvement from preoperatively to 6 months (P = .004). VAS neck scores were 8.1 (SD 1.3), 5.0 (SD 2.9), and 5.8 (SD 2.2) at preoperative, 6-month, and 1-year time points, respectively, with improvement from preoperatively to 6 months (P = .038). VAS arm scores were 5.1 (SD 4.1), 3.5 (SD 3.2), and 3.6 (SD 2.7) at preoperative, 6-month, and 1-year time points, respectively, with improvement although these did not reach statistical significance (P = .145). The most common subjective outcomes reported in the literature were general symptoms assessments (43%), ordinal scales (43%), and VAS neck (19%) scales, with the majority of studies (67%) documenting one measure.

CONCLUSIONS

Patient-reported outcomes demonstrate clinically meaningful improvement within the first 6 months after posterior fusion for pseudarthrosis. Studies demonstrate substantial variability and no standardization in outcomes reporting, limiting the ability to compare results across interventions and pathologies. Standardized reporting will enable comparisons to inform patients and physicians on the optimal approach to treat this difficult problem.

A Comparison of Patient-Centered Outcome Measures to Evaluate Dysphagia and Dysphonia After Anterior Cervical Discectomy and Fusion

OF BACKGROUND DATA

Dysphagia and dysphonia are the most common complications after anterior cervical diskectomy and fusion (ACDF). No consensus system exists currently in the spine literature for the classification of these conditions postoperatively.

OBJECTIVE

The purpose of this analysis was to evaluate the validity and reliability of the Eating Assessment Tool (EAT-10) in the assessment of dysphagia when compared with the Bazaz score. A secondary goal was to assess the Voice Handicap Index (VHI-10) scores among patients following ACDF.

METHODS

Patients treated with ACDF (one, two, or three level) for cervical radiculopathy and/or cervical myelopathy at two tertiary hospitals were administered patient-reported outcome metrics preoperatively as well as at multiple time points postoperatively. The metrics administered included the EAT-10, VHI-10, Bazaz, Neck Disbability Index, and EuroQol Five Dimensions questionnaire (EQ-5D)/visual analog scale.

RESULTS

One hundred patients were included in this study. Eighty-nine percentage had a 1-year follow-up, and 100% had a 12-week follow-up. Mean Neck Disbability Index, EQ-5D, and EQ-visual analog scale scores all improved from baseline at both 6 months and 1 year postoperatively. Both the EAT-10 and VHI-10 demonstrated excellent internal reliability (α = 0.95 and α = 0.90, respectively). Analysis of variance of EAT-10 and VHI-10 scores by time point demonstrated a statistically significant relationship (P < 0.0001). The EAT-10 and VHI-10 scores were statistically greater on postoperative day 1 than at all other times (Tukey posthoc, P < 0.0001 and P < 0.004, respectively). Across all time points, 176 instances of clinically significant dysphagia (EAT-10 ≥ 3) were noted, 57 (32%) of which were classified as "None" on the Bazaz classification.

CONCLUSIONS

The EAT-10 score is an accurate measure for mild to severe dysphagia and better captured significant dysphagia that would have otherwise been missed when the Bazaz score is used. EAT-10 and VHI-10 are better measures of postoperative dysphagia and dysphonia than the current metrics used in spine surgery.

STUDY DESIGN

This was a prospective cohort study of consecutive patients.

Is allograft a more reliable treatment option than autograft in 2-level anterior cervical discectomy and fusion with plate fixation?

This study aimed to assess the efficacy of allograft in 2-level anterior cervical discectomy and fusion (ACDF) with plate fixation by comparing its clinical and radiological outcomes to those of autograft.Thirty five patients with femur cortical allografts and 32 patients with tricortical iliac autografts were evaluated. All surgeries were performed by a single senior surgeon. During routine follow-up (at 3 months, 6 months, and annually after the surgery), the fusion rate, subsidence rate, and fused segmental lordosis angle were assessed by radiologic evaluation. Clinical outcomes were assessed using the visual analog scale (VAS), neck disability index (NDI) scores, and Odom criteria. This study was conducted using the results of the 2-year postoperative follow-up.Among 67 patients, 62 (92.5%) showed successful bone fusion at 2 years postoperatively: 91.4% (32/35) in the allograft group and 93.8% (30/32) in the autograft group. The fusion rate was 37.1% (13/35) in the allograft group and 68.8% (23/32) in the autograft group at 6 months and 68.5% (24/35) in the allograft group and 93.8% (30/32) in autograft group at 1 year. Eight (72.7%) of the remaining 11 patients with allograft achieved bone fusion without any intervention at the 2-year follow-up. The fusion was achieved faster in the autograft group than in the allograft group (P = .003). There was no significant difference in the subsidence rate or change in the fused segmental lordosis angle between the 2 groups; there was also no significant difference in clinical outcomes (NDI scores, VAS scores, Odom criteria) between the 2 groups. However, the intraoperative blood loss was significantly greater in the autograft group, and the operative time was also significantly longer in the autograft group (P < .001). In the autograft group, 6 patients (18.8%) had minor complications at the donor site.In 2-level ACDF with plate fixation, the radiologic and clinical outcomes of autograft and allograft were similar at 2-year follow-up, although fusion was observed earlier in the autograft group.

Rigid-Plating and Cortico-Cancellous Allograft Are Effective for 3-Level Anterior Cervical Discectomy and Fusion: Radiographic and Clinical Outcomes

OBJECTIVE

To determine the risk factors associated with radiographic changes and clinical outcomes following 3-level anterior cervical discectomy and fusion (ACDF) using rigidplate constructs and cortico-cancellous allograft. ACDF has demonstrated efficacy for treatment of multilevel degenerative cervical conditions, but current data exists in small heterogeneous forms.

METHODS

A retrospective review included 98 patients with primary 3-level ACDF surgery at one institution from 2008 to 2013 with minimum 1-year follow-up. Cervical sagittal vertical axis (SVA), segmental height, fusion, and lordosis radiographs were measured preoperatively and at 2 postoperative periods.

RESULTS

Rates of asymptomatic pseudarthroses and total reoperations were 18% and 4%, respectively. Results demonstrated immediate improvements in cervical lordosis (5.5°, p < 0.01) and segmental height (5.0-mm increase, p < 0.01) with little changes in the cervical SVA (3.2-mm increase, p < 0.01). The segmental height decreased from immediate postoperative period to final follow-up (1.7-mm decrease, p < 0.01). Older age was protective against radiolucent lines (p < 0.05). Patient-reported outcomes significantly improved following surgery (p < 0.01). Current smoking status and diagnosis of diabetes mellitus had no impact on radiographic or clinical outcomes. Risk factors were not identified for the 5 reoperations (4%).

CONCLUSION

Three-level ACDF with rigid-plating and cortico-cancellous allograft is an effective procedure for degenerative diseases of the cervical spine without the application of additional adjuncts or combined anteriorposterior cervical surgeries. Significant improvements in cervical lordosis, segmental height, and segmental alignment can be achieved with little change in cervical SVA and a low rate of reoperations over short-term follow-up. Similarly, patient-reported outcomes show significant improvements.

Arm Pain Versus Neck Pain: A Novel Ratio as a Predictor of Post-Operative Clinical Outcomes in Cervical Radiculopathy Patients

Background

Informed patient selection and counseling is key in improving surgical outcomes. Understanding the impact that certain baseline variables can have on postoperative outcomes is essential in optimizing treatment for certain symptoms, such as radiculopathy from cervical spine pathologies. The aim was to identify baseline characteristics that were related to improved or worsened postoperative outcomes for patients undergoing surgery for cervical spine radiculopathic pain.

Methods

Retrospective review of prospectively collected data. Patient Sample: Surgical cervical spine patients with a diagnosis classification of "degenerative." Diagnoses included in the "degenerative" category were those that caused radiculopathy: cervical disc herniation, cervical stenosis, and cervical spondylosis without myelopathy. Baseline variables considered as predictors were: (1) age, (2) body mass index (BMI), (3) gender, (4) history of cervical spine surgery, (5) baseline Neck Disability Index (NDI) score, (6) baseline SF-36 Physical Component Summary (PCS) scores, (7) baseline SF-36 Mental Component Summary (MCS) scores, (8) Visual Analog Scale (VAS) Arm score, and (9) VAS Neck. Outcome Measures: Improvement in NDI (≥50%), VAS Arm/Neck (≥50%), SF-36 PCS/MCS (≥10%) scores at 2-years postoperative. An arm-to-neck ratio (ANR) was also generated from baseline VAS scores. Univariate and multivariate analyses evaluated predictors for 2-year postoperative outcome improvements, controlling for surgical complications and technique.

Results

Three hundred ninety-eight patients were included. Patients with ANR ≤ 1 (n = 214) were less likely to reach improvements in 2-year NDI (30.0% vs 39.2%, P = .050) and SF-36 PCS (42.4% vs 53.5%, P = .025). Multivariate analysis for neck disability revealed higher baseline SF-36 PCS (odds ratio [OR] 1.053) and MCS (OR 1.028) were associated with over 50% improvements. Higher baseline NDI were reduced odds of postoperative neck pain improvement (OR 0.958). Arm pain greater than neck pain at baseline was associated with both increased odds of postoperative arm pain improvement (OR 1.707) and SF36 PCS improvement (OR 1.495).

Conclusions

This study identified specific symptom locations and health-related quality of life (HRQL) scores, which were associated with postoperative pain and disability improvement. In particular, baseline arm pain greater than neck pain was determined to have the greatest impact on whether patients met at least 50% improvement in their upper body pain score. These findings are important for clinicians to optimize patient outcomes through effective preoperative counseling.

Does Additional Uncinate Resection Increase Pseudarthrosis Following Anterior Cervical Discectomy and Fusion?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To investigate whether unilateral or bilateral uncinate resection (UR) combined with anterior cervical discectomy and fusion (ACDF) increases the risk of pseudarthrosis at long-term follow-up.

SUMMARY OF BACKGROUND DATA

Uncoforaminotomy (or UR), performed along with ACDF, facilitates better and faster improvement of arm pain. As uncovertebral joints are important for maintaining stability, they may affect the fusion process by causing segmental instability if resected during ACDF.

METHODS

We retrospectively examined 167 patients (89 men, 78 women; mean age, 58.4 ± 10.5 yr) who consecutively underwent single- or double-level ACDF and were followed for >2 years. UR was not performed in 46 patients (N-UR group). UR of at least one foramen was performed in 121 patients (UR group), including unilateral UR in 89 patients (U-UR group) and bilateral UR in 32 patients (B-UR group). Demographic data, fusion rate, visual analog scale (VAS) scores for neck/arm pain, and neck disability index (NDI) scores were compared between the N-UR and UR groups. Moreover, the fusion rates after the single- and double-level procedures were compared among the groups.

RESULTS

There was no difference in sex, age, weight, height, body mass index (BMI), and smoking history between the N-UR and UR groups. The fusion rates after single-level ACDF were not significantly different among the N-UR, U-UR, and B-UR groups (91.4%, 97.8%, and 88.2%; P = 0.290). Solid fusion was achieved in all groups after double-level ACDF (72.7%, 95.5%, and 86.7%), although the rates did not significantly differ among the groups (P = 0.071). The improvement in the VAS score for arm pain was significantly better in the UR group than in the N-UR group at short-term follow-up (P < 0.001).

CONCLUSION

Unilateral or bilateral UR does not affect the fusion rate after single- or double-level ACDF. Hence, if necessary, additional UR can be performed during ACDF without concern regarding nonunion.

LEVEL OF EVIDENCE

4.

Modified high cervical approach for C3-4 anterior pathology in difficult neck patients

Introduction:

The anterior approach to cervical pathologies is a time-tested versatile approach. It is, however, associated with a number of pharyngo-tracheo-laryngeal complications (PTL complications) such as dysphonia, dysphagia, and aspiration, more commonly in high cervical C3-4 inclusive pathologies and even more so in patients with “difficult neck.” The modified high cervical approach was devised and employed to address these issues at our institution.

Materials and Methods:

Patients who underwent surgery for anterior cervical C3-4 inclusive pathologies between January 2015 and April 2018 were included in the study. Parameters for considering difficult neck were defined. Patient subgroup with difficult neck underwent surgery through a modified high cervical approach, whereas others underwent surgery through a standard approach. The incidence of pharyngo-tracheo-laryngeal complications in both subgroups of this patient set was compared among itself as well with a similar patient set with the same two subgroups, both of which underwent surgery through standard approach alone from May 2010 to December 2014 – before the introduction of modified high cervical approach.

Results:

A total of 280 patients underwent surgery for C3-4 level pathology between May 2010 and April 2018. There were 197 males and 93 females in this population. Mean age was 45.8 ± 6.3 years. Incidence of pharyngo-tracheo-laryngeal complications was 20.3% in patients who underwent surgery before the employment of modified high cervical approach – 32.4% of difficult neck and 16.6% of others developed features of pharyngo-tracheo-laryngeal complications. After employment of modified high cervical approach, 16.67% of difficult neck and 16.2% of other patients developed features of pharyngo-tracheo-laryngeal complications.

Conclusion:

The modified high cervical technique is a good surgical option to prevent pharyngo-tracheo-laryngeal complications in cases of anterior C3-4 pathology when operating of patients with difficult neck.

What Is the Fate of Pseudarthrosis Detected 1 Year After Anterior Cervical Discectomy and Fusion?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To investigate the consequences and appropriate management of pseudarthrosis after anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Pseudarthrosis is a frequent complication of ACDF and causes unsatisfactory results. Little is known about long-term prognosis of detecting pseudarthrosis 1 year after ACDF.

METHODS

Eighty-nine patients with a minimum 2-year follow-up were included. ACDF surgery using allograft and plating was performed: single-level in 51 patients, two-level in 26 patients, and three-level in 12 patients. Presence of pseudarthrosis was evaluated 1 year postoperatively and then the nonunion segments were re-evaluated 2 years postoperatively. Demographic data were assessed to identify the risk factors associated with pseudarthrosis. A visual analogue scale for neck/arm pain and the Neck Disability Index were analyzed preoperatively and at 1 and 2 years postoperatively.

RESULTS

Pseudarthrosis was detected in 29 patients (32.6%) 1 year postoperatively: 15of 51 patients after single-level surgery, 9 of 26 patients after two-level surgery, and 5 of 12 patients after three-level surgery. Only eight patients showed persistent nonunion at 2 years: 3 of 15 patients after single-level surgery, 3 of 9 after two-level surgery, and 2 of 5 after three-level surgery. The remaining 21 patients (72.4%) achieved bony fusion 2 years postoperatively without any intervention. Patients who underwent two-level or three-level ACDF had a significantly higher pseudarthrosis rate than those who underwent single-level ACDF, with odds ratios of 1.844 and 3.147, respectively. The improvements in visual analogue scale for neck pain and Neck Disability Index scores in the persistent nonunion group were significantly lower than those in the final union group at 2 years.

CONCLUSION

Patients with pseudarthrosis detected 1 year postoperatively may be observed without any intervention because approximately 70% of them will eventually fuse by the 2-year point. Early revision could, however, be considered if the pseudarthrosis is associated with considerable neck pain after multilevel ACDF.

LEVEL OF EVIDENCE

3.

Influence of plate fixation on cervical height and alignment after one- or two-level anterior cervical discectomy and fusion

PURPOSE

To evaluate the efficacy of plate fixation on cervical alignment after anterior cervical discectomy and fusion (ACDF) using a stand-alone cage (ACDF-CA), compared to ACDF performed using a cage and plate fixation (ACDF-CP) and ACDF using autologous iliac bone graft and plate fixation (ACDF-AP), for the treatment of one- or two-level cervical degenerative disease. A second objective was to assess the clinical and radiological outcomes between the groups.

METHODS

A total of 247 patients underwent ACDF and were divided into three groups: those who underwent ACDF-CA (n = 76), ACDF-CP (n = 82) or ACDF-AP (n = 89). Fusion rate and time-to-fusion, global cervical and segmental angle, fused segment height, subsidence rate, and clinical outcomes, were measured using the visual analogue scale (VAS), Oswestry Neck Disability Index (NDI), and Robinson's criteria, assessed preoperatively, immediately postoperatively, and at least 24 months, postoperatively.

RESULTS

ACDF-AP was associated with the shortest mean time-to-fusion, followed by ACDF-CP and ACDF-CA. Compared to the preoperative status, the fused segment height and segmental angle increased in all groups immediately postoperatively, being well-maintained in patients who underwent ACDF-AP, while decreasing in those who underwent ACDF-CP and ACDF-CA procedures. Global cervical lordosis increased with ACDF-AP, but decreased immediately postoperatively with ACDF-CP and ACDF-CA, and at the final follow-up. Univariate analysis confirmed that a change in fused segment height was positively associated with a change in both segmental and global cervical angles. Clinical outcomes, namely VAS and NDI scores, as well as Robinson's criteria, were comparable among the three techniques.

CONCLUSIONS

Supplementation with plate fixation, especially using autologous iliac bone graft, is beneficial for maintaining the fused segment height and cervical spine curvature, as well as reducing time-to-fusion and subsidence rate.

Cage with anterior plating is advantageous over the stand-alone cage for segmental lordosis in the treatment of two-level cervical degenerative spondylopathy: A retrospective study

OBJECTIVES

To compare retrospectively the clinical and radiological outcomes in cervical spinal alignment after two consecutive levels PEEK cage-assisted ACDF when performed with or without plate fixation PATIENTS AND METHODS: Seventy-eight patients underwent two consecutive levels PEEK cage-assisted ACDF without plating (56 patients) or supplemented with plating (22 patients). The average clinical follow-up was 31.40±12.98months. The authors compared clinical parameters (Neck disability index and Robinson criteria), perioperative parameters (hospital stays, complications), and radiological parameters (global lordotic curvature, segmental lordosis, segmental height).

RESULTS

Demographic features, neurological presentation, preoperative sagittal alignment, postoperative complications, length of hospitalization and clinical improvement were not different between groups. At 12-months radiological follow-up, the global lordotic curvature was similar in both groups (P=0.02). However, the use of anterior plate fixation versus stand-alone cage was associated with greater segmental lordosis (-7.68±4.82° versus -0.02±8.44°, P<0.0001) and greater segmental height (39.51±3.50 versus 36.75±3.90, P=0.005).

CONCLUSION

The clinical outcomes after two consecutive levels PEEK cage-assisted ACDF with and without plate fixation were similar, but the supplement of an anterior plate was advantageous for improving segmental alignment on long-term radiological follow-up.

Titanium cages versus autogenous iliac crest bone grafts in anterior cervical discectomy and fusion treatment of patients with cervical degenerative diseases: a systematic review and meta-analysis

OBJECTIVE

A systematic review and partial meta-analysis is conducted to compare the efficacy and safety of anterior cervical decompression and fusion procedures employing either rectangular titanium cages or iliac crest autografts in patients suffering from cervical degenerative disc diseases.

METHODS

Medline, PubMed, CENTRAL, and Google Scholar databases were searched up to June 2015, using the key words cervical discectomy; bone transplantation; titanium cages; and iliac crest autografts. Outcomes of interbody fusion rates were compared using odds ratios (ORs) with 95% confidence intervals (CIs). Values of the Japanese Orthopaedic Association score, and visual analog scale before and after operation were also compared.

RESULTS

The rate of interbody fusion was similar between patients in the iliac crest autograft and titanium cage groups (pooled OR = 0.33, 95% CI = 0.07 to 1.66, P = .178). The overall analysis showed that patients in the two groups did not have significantly different post-surgery Japanese Orthopaedic Association score (pooled difference in means = -0.05, 95% CI = 0.73 to 0.63, P = .876). Improvement in arm and neck pain scores were assessed with a visual analog scale and differed significantly between patients in the iliac crest autograft and titanium cage groups (pooled difference in means = 0.16, 95% CI = -0.44 to 0.76, P = .610; and pooled difference in means = -0.44, 95% CI = -2.23 to 1.36, P = .634, respectively).

CONCLUSIONS

Our results suggest that the use of titanium cages constitutes a safe and efficient alternative to iliac crest bone autografts for anterior cervical discectomy with fusion.

A rare case of pharyngeal perforation and expectoration of an entire anterior cervical fixation construct

Anterior cervical discectomy and fusion (ACDF) is a very common surgery performed globally. Although a few cases of expectorating screws or extrusion of screws into the gastrointestinal tract through esophageal perforations have previously been reported, there has not been a case reporting pharyngeal perforation and entire cervical construct extrusion in the literature to date. In this report the authors present the first case involving the extrusion of an entire cervical construct via a tear in the posterior pharyngeal wall. An 81-year-old woman presented to the emergency department (ED) with a complaint of significant cervical pain 5 days after a fall due to a syncopal event. Radiological findings showed severe anterior subluxation of C-2 on C-3 with no spinal cord signal change noted. She underwent ACDF at the C2–3 level utilizing a polyetheretherketone (PEEK) cage, allograft, autograft, and a nontranslational plate with a locking apparatus and expanding screws. The screw placement was satisfactory on postoperative radiography and the Grade II spondylolisthesis of C-2 on C-3 was reduced appropriately with the surgery. The postoperative radiographs obtained demonstrated good instrumentation placement. Three and a half years later the patient returned to the ED having expectorated the entire anterior cervical construct. A CT scan demonstrated the C-2 and C-3 vertebral bodies to be fused posteriorly with an anterior erosive defect within the vertebral bodies and the anterior fusion hardware at the C2–3 level no longer identified. The fiberoptic laryngoscopy demonstrated a 1 × 1 cm area over the importation of the hypopharynx, above the glotic area. The Gastrografin swallowing test ruled out any esophageal tear or fistula and confirmed the presence of a large ulcer on the posterior wall of the oropharynx. To the best of the authors' knowledge, this is the first ever reported case of a tear in the posterior pharyngeal wall along with extrusion of the entire cervical construct after ACDF. This case demonstrates a rare but potentially serious complication of ACDF. Based on the available literature, each case requires separate and distinct treatment from the others.

Surgical Outcomes of Anterior Cervical Fusion Using Deminaralized Bone Matrix as Stand-Alone Graft Material: Single Arm, Pilot Study

Objective

To investigate the safety and efficacy of demineralized bone matrix (DBM) as a bone graft substitute for anterior cervical discectomy and fusion (ACDF) surgery.

Methods

Twenty consecutive patients treated with ACDF using stand-alone polyestheretherketone (PEEK) cages (Zero-P) with DBM(CGDBM100) were prospectively evaluated with a minimum of 6 months of follow-up. Radiologic efficacy was evaluated with a 6-point scoring method for osseous fusion using plain radiograph and computed tomogrpahy scans. Clinical efficacy was evaluated using the visual analogue scale (VAS), Owestry disability index (ODI), and short-form health questionnaire-36. The safety of the bone graft substitute was assessed with vital sign monitoring and a survey measuring complications at each follow-up visit.

Results

There were significant improvements in VAS and ODI scores at a mean 6-month follow-up. Six months after surgery, solid fusion was achieved in all patients. Mean score on the 6-point scoring system was 5.1, and bony formation was found to score at least 4 points in all patients. There was no case with implant-related complications such as cage failure or migration, and no complications associated with the use of CGDBM100.

Conclusion

ACDF using CGDBM100 demonstrated good clinical and radiologic outcomes. The fusion rate was comparable with the published results of traditional ACDF. Therefore, the results of this study suggest that the use of a PEEK cage packed with DBM for ACDF is a safe and effective alternative to the gold standard of autologous iliac bone graft.

Pseudarthrosis of the Cervical Spine: Risk Factors, Diagnosis and Management

Cervical myelopathy and radiculopathy are common pathologies that often improve with spinal decompression and fusion. Postoperative complications include pseudarthrosis, which can be challenging to diagnose and manage. We reviewed the literature with regard to risk factors, diagnosis, controversies, and management of cervical pseudarthrosis.

Anterior Cervical Reconstruction Using Free Vascularized Fibular Graft after Cervical Corpectomy

Study Design Prospective study. Objective The aim of this study was to evaluate the clinical and radiologic results of using free vascularized fibular graft (FVFG) for anterior reconstruction of the cervical spine following with varying levels of corpectomy. Methods Ten patients underwent anterior cervical reconstruction using an FVFG after cervical corpectomy augmented with internal instrumentation. All patients were evaluated neurologically according to the Japanese Orthopaedic Association (JOA) and modified JOA scoring systems and the Nurick grading system. The neurologic recovery rate was determined, and the clinical outcome was assessed based on three factors: neck pain, dependence on pain medication, and ability to return to work. The fusion status and maintenance of lordotic correction by the strut graft were determined by measuring the lordosis angle and fused segment height (FSH). Results All patients achieved successful fusion. The mean follow-up period was 35.2 months (range, 28 to 44 months). Graft union occurred at a mean of 3.5 months. The mean loss of lordotic correction was 0.95 degrees, and the mean change in FSH was <1 mm. The neurologic recovery rate was excellent in four patients, good in five, and fair in one. All patients achieved satisfactory clinical outcome. No neurologic injuries occurred during the operations. Conclusion The use of FVFG is a valuable and effective technique in anterior cervical reconstruction for complex disorders.

Obesity Is an Independent Risk Factor of Early Complications After Revision Spine Surgery

STUDY DESIGN

Retrospective cohort analysis of risk factors in revision spine surgery using a prospectively collected database.

OBJECTIVE

To examine the risk of developing early (30-day) complications across obesity level after adjusting for comorbidities in patients undergoing revision spine surgery.

SUMMARY OF BACKGROUND DATA

Prior studies suggest obesity influences early complications after primary surgery. The association between obesity and early complications after revision surgery remains to be characterized.

METHODS

Data were abstracted from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2005 to 2012. Adult Caucasian patients undergoing removal/revision of instrumentation or exploration of fusion were included. Patients were categorized by WHO body mass index (BMI, kg/m): Non-Obese (18.5-29.9), Obese Class I (30-34.9), and Obese Class II/III (≥35). Univariate regression was performed to assess the predictive value of obesity level and baseline risk factors in the presence of at least one early complication, and significant predictors were entered into the multivariable model.

RESULTS

Of 2538 patients, 57.6% were nonobese, 23% Obese Class I, and 19.4% Obese Class II/III. Obesity was associated with diabetes, hypertension, respiratory disease, and American Society of Anesthesiologists (ASA) score of 3-4 (all P < 0.001). BMI group (P = 0.01), older age (P = 0.008), functional dependence (P < 0.001), ASA 3-4 (P = 0.008), bleeding disorder (P = 0.04), and diabetes (P = 0.016) were identified as univariate predictors for early complications. In the multivariable model, higher BMI (P = 0.04), older age (P = 0.014), and functional dependence (P < 0.001) remained significant predictors for early complications. Notably, patients who were Obese Class II/III (OR 1.66, 95% CI [1.12-2.45]), age ≥75 (OR 1.83, [1.20-2.81]), and functionally dependent (OR 3.02 [1.85-4.94]) had significantly higher risk compared with their reference groups.

CONCLUSION

Obesity is an independent risk factor for early complications after revision spine surgery. Although obesity may not contraindicate revision surgery, its status as a modifiable risk factor warrants disclosure and preoperative counseling to optimize outcomes.

LEVEL OF EVIDENCE

3.

Complications of Anterior and Posterior Cervical Spine Surgery

Cervical spine surgery performed for the correct indications yields good results. However, surgeons need to be mindful of the many possible pitfalls. Complications may occur starting from the anaesthestic procedure and patient positioning to dura exposure and instrumentation. This review examines specific complications related to anterior and posterior cervical spine surgery, discusses their causes and considers methods to prevent or treat them. In general, avoiding complications is best achieved with meticulous preoperative analysis of the pathology, good patient selection for a specific procedure and careful execution of the surgery. Cervical spine surgery is usually effective in treating most pathologies and only a reasonable complication rate exists.

Stand-Alone Cages for Anterior Cervical Fusion: Are There No Problems?

Objective

There are complications in stand-alone cage assisted anterior cervical discectomy and fusion (ACDF), such as cage subsidence and kyphosis. Here we report our clinical result on ACDF, comparing with stand-alone cages and with cervical plate system for degenerative cervical spine diseases.

Methods

Patients with degenerative cervical disease who were diagnosed and treated in Konyang University Hospital between January 2004 and December 2014 were included in this study. Patients who had operation in single level ACDF were selected. Patients scored the degree of pain using visual analog scale before and after the surgery. Subsidence was defined as ≥3-mm decrease of the segmental height, and cervical kyphosis was defined as progression of ≥5° at 12 months after postoperative follow-up compared to that measured at the immediate postoperative period.

Results

A total of 81 patients were enrolled for this study. Forty-five patients were included in a cervical plate group and the others were in stand-alone cage group. There was no statistical difference in pain score between the 2 groups. Segmental subsidence was observed in 7 patients (15.6%) in plate-assisted cervical fusion group, and 13 patients (36.1%) in stand-alone cage group. Segmental kyphosis was observed in 4 patients (8.9%) in plate-assisted cervical fusion group, and 10 patients (27.8%) in stand-alone cage group. There was statistical difference between the 2 groups.

Conclusion

There was no difference in pain between 2 groups. But stand-alone case group showed higher incidence rate than plate-assisted cervical fusion group in segmental subsidence and cervical kyphosis. When designing cervical fusion, more attention should be given selecting the surgical technique.

Comparison of the clinical and radiologic outcomes obtained with single- versus two-level anterior cervical decompression and fusion using stand-alone PEEK cages filled with allograft

BACKGROUND

Although anterior cervical decompression and fusion with a stand-alone cage (ACDF-SAC) is accepted as a suitable procedure, the outcomes of the multi-level procedure remain controversial. The aim of this study is to compare the clinical and radiologic outcomes achieved with single versus two-level ACDF-SAC along with identification of the factors that contribute to loss in mean disc height (MDH) and change in cervical lordotic angle (CLA).

METHODS

A total of 109 consecutive patients who underwent ACDF-SAC for degenerative spondylosis were reviewed. Patients were divided into two groups according to surgical level (group A, single; group B, two) and were followed for at least 1 year. Clinical outcomes were evaluated using the visual analog scale (VAS) and Robinson's criteria. The fusion and subsidence rates, MDH, CLA, anterior, and posterior vertebral body height of the fused segments (AVBH, PVBH) were measured retrospectively from plain radiographs.

RESULTS

Clinical outcomes were similar in both groups, in terms of decreasing VAS score and a grade higher than "good" by Robinson's criteria. The fusion and subsidence rates for each group were found to be 92.2, 91.1, 14.1, and 20.0 %, respectively. The MDH (mm) increased by 1.44 ± 0.96 in group A, 1.57 ± 0.79 and 1.66 ± 0.69 for each surgical level in group B over the 12 postoperative months. The CLA (°) decreased by 1.70 ± 4.04 and 0.75 ± 6.12 over the 12 postoperative months from its presurgery value, the rate of kyphosis >5° was 26.6 and 22.2 % for each group. All compared values were not significantly different between the two groups. Correlation analysis revealed that the AVBH/PVBH ratio exhibited a positive correlation with CLA change in both groups (r = 0.368, 0.397; p = 0.018, 0.040).

CONCLUSIONS

The overall outcomes achieved with two-level ACDF-SAC were similar to those achieved with single-level ones. In addition, the AVBH/PVBH ratio might be a predictable marker for a postoperative kyphosis.

Comparison of 1-Level Versus 2-Level Anterior Cervical Discectomy and Fusion: Clinical and Radiographic Follow-Up at 60 Months

STUDY DESIGN

This study represents a posthoc analysis of data collected from 2 control arms of a prospective, randomized study.

OBJECTIVE

The purpose of this study was to compare results of patients undergoing 1- versus 2-level anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

For single-level ACDF, reported outcomes have generally been good; however, results for 2 levels have been less consistent.

METHODS

This 60-month follow-up study was based on data from the prospective Food and Drug Administration regulated Mobi-C artificial disc trial. Serving as the control, ACDF was performed at 1 level in 81 patients and 2 levels in 105 patients. Study selection criteria, fusion technique, and outcome measures were identical, with the only exception being the number of levels that were pathological and operated.

RESULTS

Neck Disability Index (NDI) scores, visual analog scales assessing neck and arm pain, and SF-12 scores improved significantly in both groups. Significant differences were observed between groups on NDI and SF-12 PCS scores through 60 months. Fusion rates were 93.3% in the 1-level group and 86.1% in the 2-level (60 months, not significantly different). Adjacent segment degeneration occurred in 54.7% of patients at the superior level and 44.7% at the inferior segment in the 1-level group and 70.8%, and 55.0% respectively in 2-level patients (trend at superior level; 0.05 < P < 0.10). Subsequent index level surgery was performed in 11.1% of single-level patients versus 16.2% of the 2-level group (not significantly different).

CONCLUSION

One- and 2-level ACDF groups improved significantly and maintained improvement throughout 60 month follow-up. When comparing groups, outcomes were often similar, though the 1-level group demonstrated higher fusion rates at 6 and 12 months, greater improvement in NDI scores from 18 to 60-month follow-up, and greater improvement in SF-12 PCS from 12 to 60 months.

A novel technique to practice using a high-speed burr for spinal anterior cervical discectomy and fusion

BACKGROUND

Anterior cervical discectomy and fusion has been a successful procedure in terms of patient satisfaction in the management of cervical myelopathy and radiculopathy. The procedure involves an anterior approach to the cervical vertebral column and decompression of the neural elements.

AIM

A key part of the procedure is the removal of the posterior osteophyte. This is usually performed using a high-speed burr. In inexperienced hands, this part of the procedure can be a challenging one.

MATERIALS

Egg, egg cup, zinc oxide tape and high-speed burr.

CONCLUSION

We describe a simple and cost effective method of practicing this manoeuver, enabling the trainee to gain sufficient confidence in handling the tool around delicate tissues.

Reoperation Rates for Symptomatic Nonunions in Anterior Cervical Fusions From a National Spine Registry

STUDY DESIGN

A retrospective cohort study with chart review.

OBJECTIVE

To determine the reoperation rates for symptomatic nonunions for 1-level, 2-level, and 3-level anterior cervical discectomies and fusions (ACDFs) from a national spine registry.

SUMMARY OF BACKGROUND DATA

There is very little data reported in the literature on reoperation rates for symptomatic nonunions after ACDFs. The reported nonunion rates are primarily based on radiographical evidence, although some of these may be asymptomatic. Similarly, there may be symptomatic patients with nonunions who elect not to have a reoperation. We think, however, data from a national spine registry provide a realistic and unbiased assessment of routine cervical spine fusion care and represent a heterogeneous population with varied indications and surgical techniques and are best suited to determine reoperations for symptomatic nonunions.

METHODS

Using data from a Spine Implant Registry developed at a large integrated health care system (Kaiser Permanente), patients with ACDFs between January 2009 and December 2012 with 2-year follow-up were identified. Patient characteristics, admitting diagnosis, and number of levels fused were extracted from the registry. Reoperations for symptomatic nonunions from the index spinal procedure were identified by chart review.

RESULTS

A cohort of 1054 patients with more than 2 years of follow-up were found to have reoperations for nonunions of 0.2%, 2.9%, and 6.5% for 1-level, 2-level, and 3-level ACDFs, respectively.

CONCLUSION

A large cohort of ACDF patients with more than 2 years of follow-up had reoperations for nonunion rates significantly lower than reported in the literature for radiographical nonunions. We think our data add to the literature an important parameter (reoperations for nonunion rates) and provide useful information for patients, spine surgeons, and health care payers.

Cervical Arthroplasty for Traumatic Disc Herniation: An Age- and Sex-matched Comparison with Anterior Cervical Discectomy and Fusion

BACKGROUND

The efficacy and safety of using cervical arthroplasty for degenerative disc disease have been demonstrated by prospective, randomized and controlled clinical trials. However, there are scant data on using cervical arthroplasty for traumatic disc herniation. Therefore, this study aimed to investigate the outcomes of patients who underwent cervical arthroplasty for traumatic disc herniation.

METHODS

This cohort included patients who were admitted through the emergency department for trauma. Only patients who had newly-onset, one- or two-level cervical disc disease causing radiculopathy or myelopathy were identified. None of these patients had previously sought for medical attention for such problems. Those patients who had severe spinal cord injury (i.e. American Spinal Injury Association scale A, B or C) or severe myelopathy (i.e. Nurick scale 4 or 5), bony fracture, dislocation, perched facet, kyphotic deformity, or instability were also excluded. An age- and sex-matched one-to-one comparison was made between patients who underwent cervical arthroplasty, on the one hand, and anterior cervical discectomy and fusion (ACDF).

RESULTS

A total of 30 trauma patients (15 in the arthroplasty group and 15 in the ACDF group) were analyzed, with a mean follow-up of 29.6 months. The demographic data were similar. Post-operation, the arthroplasty group had significant improvement in VAS of neck and arm pain, JOA, and NDI when compared to their pre-operation status. Similarly, the ACDF group also improved significantly after the operation. There were no differences between the two groups in post-operative VAS neck and arm pain, and JOA scores. The arthroplasty group maintained a range of motion in the indexed levels and had better NDI scores at 6-months post-operation than the ACDF group.

CONCLUSIONS

For selected patients (i.e. no spinal cord injury, no fracture, and no instability) with traumatic cervical disc herniation, cervical arthroplasty yields similar improvement in clinical outcomes to ACDF and preserves segmental mobility.

A Meta-Analysis of the Clinical and Fusion Results following Treatment of Symptomatic Cervical Pseudarthrosis

Study Design Systematic literature review and meta-analysis. Objective This study is a meta-analysis assessing the fusion rate and the clinical outcomes of cervical pseudarthrosis treated with either a posterior or a revision anterior approach. Methods A literature search of PubMed, Cochrane, and Embase was performed. Variables of interest included fusion rate and clinical success. The effect size based on logit event rate was calculated from the pooled results. The studies were weighted by the inverse of the variance, which included both within- and between-study error. The confidence intervals were reported at 95%. Heterogeneity was assessed using the Q statistic and I (2), where I (2) is the estimate of the percentage of error due to between-study variation. Results Sixteen studies reported fusion outcomes; 10 studies reported anterior and/or posterior results. The pooled fusion success was 86.4% in the anterior group and 97.1% in the posterior group (p = 0.028). The anterior group demonstrated significant heterogeneity with Q value of 34.2 and I (2) value of 73.7%; no heterogeneity was seen in the posterior group. The clinical outcomes were reported in 10 studies, with eight reporting results of anterior and posterior approaches. The pooled clinical success rate was 77.0% for anterior and 71.7% for posterior (p = 0.55) approaches. There was significant heterogeneity in both groups (I (2) 16.1; 19.2). Conclusions Symptomatic cervical pseudarthrosis can be effectively managed with either an anterior or a posterior approach. The posterior approach demonstrates a significantly greater fusion rate compared with the anterior approach, though the clinical outcome does not differ between the two groups.

Surgical Outcome of a Zero-profile Device Comparing with Stand-alone Cage and Anterior Cervical Plate with Iliac Bone Graft in the Anterior Cervical Discectomy and Fusion

Objective

A Zero-profile device is a cervical stand-alone cage with integrated segmental fixation device. We characteristically evaluated the radiological changes as well as clinical outcomes in the application of Zero-profile devices compared with stand-alone cages and anterior cervical plates with iliac bone grafts for the cervical disease.

Methods

Retrospectively, total 60 patients at least more than one year follow-up were enrolled. Twenty patients were treated with Zero-profile devices (Group A), twenty patients with stand-alone cages (Group B) and twenty patients with anterior cervical plates and iliac bone grafts (Group C) for a single level cervical disease. The clinical outcomes were evaluated by Odom's criteria and Bazaz-Yoo dysphagia index. The radiologic parameters were by subsidence and the changes of the midpoint interbody height (IBH), the segmental kyphotic angle (SKA), the overall kyphotic angle (OKA) in index level.

Results

Although there was no significant clinical difference according to the Odom's criteria among them(p=0.766), post-operative dysphagia was significantly decreased in the Group A and B compared with the Group C (p=0.04). From the immediate postoperative to the last follow-up time, the mean change of IBH decrement and SKA increment were significant in the Group B compared with the Group A (p=0.025, p=0.033) and the Group C (p=0.001, p=0.000). The subsidence rate was not significant among all groups (p=0.338).

Conclusion

This Zero-profile device is a valuable alternative to the anterior cervical discectomy and fusion with a low incidence of postoperative dysphagia and without segmental kyphotic change.

Stand-alone cervical cages versus anterior cervical plate in 2-level cervical anterior interbody fusion patients: clinical outcomes and radiologic changes

STUDY DESIGN

Retrospective study.

OBJECTIVES

To compare the efficacy of 2-level anterior cervical discectomy and fusion with cage alone (ACDF-CA) and with cage and plate construct (ACDF-CPC) with regard to clinical outcome and radiologic changes.

SUMMARY OF BACKGROUND DATA

The use of stand-alone cervical interbody cages in ACDF has become popular, but high subsidence rates have been reported in the literature.

METHODS

A total of 54 consecutive patients who underwent 2-level ACDF-CA or ACDF-CPC after suffering from cervical radiculopathy were divided into 2 groups: group A (n = 28) underwent ACDF-CA, group B (n = 26) underwent ACDF-CPC. Fusion rate, global and segmental kyphosis, disk height, and subsidence rate were assessed by radiolographs. Clinical outcomes were assessed using Robinson's criteria.

RESULTS

Solid fusion was achieved in 96.43% (27/28) in group A and in 96.15% (25/26) in group B. Fusion segmental kyphosis of >5 degrees occurred in 14.29% (4/28) of group A and in 7.69% (2/26) of group B; however, there was no statistical difference between the 2 groups (P>0.05). Subsidence occurred in 35.71% (10/28) of group A as compared with 11.54% (3/26) of group B (P<0.05). Clinical outcomes were similar in the 2 treatment groups.

CONCLUSIONS

The use of cage and plate construct in 2-level ACDF results in a shorter fusion duration and a lower subsidence rate than that of cage alone; however, there is no significant difference in the postoperative global and segmental alignment and clinical outcomes between groups.

Fate of osteophytes and sclerosis in fused segments after lumbar fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate the fate of sclerosis and anterior osteophytes in the fused segments after instrumented lumbar fusion for degenerative lumbar disorders.

SUMMARY OF BACKGROUND DATA

Sclerosis and osteophytosis are well-known radiographical findings, but little is known of their significance with regard to spontaneous resorption after spine fusion.

METHODS

Thirty patients (9 males, 21 females; 60 vertebra; mean age of 66.9 yr [45-86 yr]) were divided into a posterolateral fusion group (n = 14, 28 vertebrae) and a posterior lumbar interbody fusion group (n = 16, 32 vertebrae). Using serial radiographs obtained preoperatively; postoperatively at 3, 6, 12, and 24 months; and last follow-up, sclerotic areas of each involved vertebra were mapped and osteophyte lengths were measured.

RESULTS

Sclerosis and osteophytes decreased with time for the instrumented fusion. The decrease in sclerotic areas and osteophytes length was observed as early as 3 months postoperatively, and the significant changes between each time point were noted in initial 3- and 6-month intervals. In terms of the type of surgery, similar changes were noted in the posterolateral fusion and posterior lumbar interbody fusion groups.

CONCLUSION

Resorption of osteophytes and sclerosis after instrumented spine fusion were observed. Significant resorption was noted at 3 and 6 months postoperatively. As well, most graft bone would be incorporated in postoperative 6 months. Resorption of osteophytes and sclerosis after instrumented spine fusion could be helpful to confirm the successful union.

LEVEL OF EVIDENCE

4.

National trends in revision spinal fusion in the USA

Using the United States Nationwide Inpatient Sample, we identified national trends in revision spinal fusion along with a comprehensive comparison of comorbidities, inpatient complications and surgical factors of revision spinal fusion compared to primary spinal fusion.

In 2009, there were 410 158 primary spinal fusion discharges and 22 128 revision spinal fusion discharges. Between 2002 and 2009, primary fusion increased at a higher rate compared with revision fusion (56.4% vs 51.0%; p < 0.001). In 2009, the mean length of stay and hospital charges were higher for revision fusion discharges than for primary fusion discharges (4.2 days vs 3.8 days, p < 0.001; USD $91 909 vs. $87 161, p < 0.001). In 2009, recombinant human bone morphogenetic protein (BMP) was used more in revision fusion than in primary fusion (39.6% vs 27.6%, p < 0.001), whereas interbody devices were used less in revision fusion (41.8% vs 56.6%, p < 0.001).

In the multivariable logistic regression model for all spinal fusions, depression (odds ratio (OR) 1.53, p < 0.001), psychotic disorders (OR 1.49, p < 0.001), deficiency anaemias (OR 1.35, p < 0.001) and smoking (OR 1.10, p = 0.006) had a greater chance of occurrence in revision spinal fusion discharges than in primary fusion discharges, adjusting for other variables. In terms of complications, after adjusting for all significant comorbidities, this study found that dural tears (OR 1.41; p < 0.001) and surgical site infections (OR 3.40; p < 0.001) had a greater chance of occurrence in revision spinal fusion discharges than in primary fusion discharges (p < 0.001). A p-value < 0.01 was considered significant in all final analyses.

Cite this article: Bone Joint J 2014;96-B:807–16.

Anterior cervical diskectomy and fusion for adjacent segment disease

Between January 1996 and December 2005, a total of 1241 patients underwent anterior cervical decompression and fusion for cervical degenerative diseases in the authors' institution. Sixty-three (5.1%) patients underwent revision anterior cervical diskectomy and fusion for adjacent segment disease between October 2003 and August 2010. This series included 35 men and 28 women with a mean±SD age of 52.6±6.7 years. A total of 81 segments underwent revision surgery, and most were distributed at C3-C4 and C6-C7. Patients were evaluated using the visual analog scale and Japanese Orthopaedic Association score pre- and postoperatively. Postoperative plain radiographs were used to detect implant failure, segmental collapse, and bone fusion. Clinical symptoms significantly improved postoperatively, and the rate of excellent and good outcomes reached 71.4% at 2-year follow-up. Five (7.9%) patients developed transient mild dysphagia postoperatively. No instrument failure or segmental collapse caused by implant subsidence was detected at the final 2-year follow-up, but 3 (4.8%) patients who received a polyetheretherketone cage did not develop solid fusion.Revision anterior cervical decompression and fusion provided results comparable with those of anterior cervical decompression and fusion as a primary surgery, and no clinical results were associated with the number of operated levels or instrument device type. Therefore, revision surgery does not adversely affect clinical results when performing anterior cervical decompression and fusion in patients with adjacent segment disease, and a Zero-P cage (Synthes GmbH, Oberdorf, Switzerland) is recommended for use in patients due to higher fusion rates.