Anterior cervical discectomy and fusion (ACDF) autograft versus graft substitutes: what do patients prefer?-A clinical study

Synthetic Interbody Devices and Traditional Bone Graft Are Associated With a Similar Rate of Surgical Complications After 1-2 Level Anterior Cervical Discectomy and Fusions

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To compare the rates of all-cause surgical complications of synthetic interbody devices versus allograft or autograft in patients undergoing 1-2 levels anterior cervical discectomy and fusion (ACDF) procedures.

SUMMARY OF BACKGROUND DATA

Cervical degenerative disorders affect up to 60% of older adults in the United States. Both traditional allograft or autograft and synthetic interbody devices (polyetheretherketone or titanium) are used for decompression and arthrodesis, with increasing utilization of the latter. However, the differences in their postsurgical complication profiles are not well-characterized.

PATIENTS AND METHODS

Patients who underwent 1-2 level ACDFs for cervical radiculopathy or myelopathy between 2010 and 2022 were identified using the PearlDiver Mariner all-claims insurance database. Patients undergoing surgery for nondegenerative pathologies, such as tumors, trauma, or infection, were excluded. 1:1 exact matching was performed based on factors that were significant predictors of all-cause surgical complications in a linear regression model. The primary outcome measure was the development of all-cause surgical complications after 1-2 level ACDFs. The secondary outcome was all-cause medical complications.

RESULTS

1:1 exact matching resulted in two equal groups of 11,430 patients who received treatment with synthetic interbody devices or allograft/autograft. No statistically significant difference in all-cause surgical complications was found between the synthetic cohort and the allograft or autograft cohort after 1-2 level ACDFs (Relative Risk: 0.86, 95% confidence interval: 0.730-1.014, P = 0.079). No significant differences were observed regarding any specific surgical complications except for pseudoarthrosis (Relative Risk: 0.73, 95% confidence interval: 0.554-0.974, P = 0.037), which was higher in the allograft/autograft cohort.

CONCLUSION

After 1:1 exact matching to control for confounding variables, the findings of this study suggest that all-cause surgical complications are similar in patients undergoing ACDFs with synthetic interbody devices or allograft/autographs. However, the rate of pseudarthrosis appears to be higher in patients with allograft/autographs. Future prospective studies are needed to corroborate these findings.

Safety and Efficacy of Zero-Profile Polyetheretherketone (PEEK) Cages Filled with Biphasic Calcium Phosphate (BCP) in Anterior Cervical Discectomy and Fusion (ACDF): A Case Series

Background: In the evolving landscape of anterior cervical discectomy and fusion (ACDF), the integration of biomechanical advancements and proper fusion-enhancing materials is crucial for optimizing patient outcomes. This case series evaluates the efficacy and clinical implications of employing zero-profile polyetheretherketone (PEEK) cages filled with biphasic calcium phosphate (BCP) in ACDF procedures, focusing on fusion and subsidence rates alongside patient disability, residual pain, and quality of life. Methods: This case series comprises 76 consecutive patients, with a median follow-up of 581 days. The Bridwell classification system was used for assessing fusion rates while subsidence occurrence was recorded, correlating these radiographic outcomes with clinical implications. Results: The results demonstrated a satisfactory fusion rate (76.4% for grades I and II). The subsidence rate was low (6.74% of segments). Significant clinical improvements were observed in pain, disability, and quality-of-life metrics, aligning with the minimum clinically important difference thresholds; however, subgroup analyses demonstrated that subsidence or pseudoarthrosis group improvement of PROMs was not statistically significant with respect to baseline. ANOVA analyses documented that subsidence has a significant weight over final follow-up pain and disability outcomes. No dysphagia cases were reported. Conclusions: These findings underscore the efficacy of zero-profile PEEK cages filled with BCP in ACDF, highlighting their potential to improve patient outcomes while minimizing complications. Pseudoarthrosis and subsidence have major implications over long-term PROMs. The study reinforces the importance of selecting appropriate surgical materials to enhance the success of ACDF procedures.

Do Osteobiologics Augment Fusion in Anterior Cervical Discectomy and Fusion Surgery Performed With Mechanical Interbody Devices (Polyether ether ketone, Carbon Fiber, Metal Cages) and is the Fusion Rate Comparable to that With Autograft? A Systematic Review

STUDY DESIGN

Systematic Review of the Literature.

OBJECTIVE

The purpose of this study was to perform a systematic review describing fusion rates for anterior cervical discectomy and fusion (ACDF) using autograft vs various interbody devices augmented with different osteobiologic materials.

METHODS

A systematic review limited to the English language was performed in Medline, Embase and Cochrane library using Medical Subject Heading (MeSH) terms. Studies that evaluated fusion after ACDF using autografts and osteobiologics combined with PEEK, carbon fibre, or metal cages were searched for. Articles in full text that met the criteria were included in the review. The main outcomes evaluated were the time taken to merge, the definition of the fusion assessment, and the modality of the fusion assessment. The risk of bias of each article was assessed by the MINORS score or ROB 2.0 depending on the randomisation process.

RESULTS

The total number of references reviewed was six hundred and eighty-two. After applying the inclusion criteria, 54 were selected for the retrieval of the full text. Eight studies were selected and included for final analysis in this study. Fusion rates were reported between 83.3% and 100% for autograft groups compared to 46.5% and 100% for various interbody device/osteobiological combinations. The overall quality of the evidence in all radiographic fusion studies was considered insufficient due to a serious risk of bias.

CONCLUSION

Mechanical interbody devices augmented with osteobiologics performed similarly to autografts in terms of reliability and efficacy. Their time to fusion and fusion rate were comparable to autografts at the end of the final follow-up.

[Comparison of cervical fusion with autografting of fibula vs titanium cage]

Background

The anterior cervical discectomy and fusion (ACDF) is the gold standard in the treatment of cervical compression pathology and the titanium cage for fusion represents the most used procedure at an institutional level. A technique using fibular autograft has been described, with good results, lower morbidity and lower cost.

Objective

To compare the rate of fusion, subsidence and functional clinical results after discectomy with titanium cage and fibular autograft.

Material and methods

A clinical trial with follow-up at 3 and 6 months was carried out in patients diagnosed with cervical spondylosis, candidates for ACDF. 2 groups were formed: fibular autograft and titanium cage. Pre and post functional evaluation using the cervical disability score was made, as well as radiographic fusion and subsidence evaluation. Descriptive statistics, Fisher's exact test, t-test and ANOVA were obtained, establishing p < 0.05.

Results

A sample of 20 patients with an average age of 56 years was obtained, finding a fusion rate of 90% for fibular autograft and 30% for titanium (p = 0.02) at 3 months. 10% of patients with fibular autograft presented subsidence and 70% with titanium cage at 3 and 6 months (p = 0.02). In the functional results was not found difference between both procedures (p = 0.874).

Conclusions

The use of autologous fibular graft offers a better rate of fusion and subsidence compared to the titanium cage, as well as similar functional results at 3 months of follow-up. It represents an excellent treatment option for cervical spondylosis.

Clinical Outcomes and Cost Profiles for Cage and Allograft Anterior Cervical Discectomy and Fusion Procedures in the Adult Population: A Propensity Score-Matched Study

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To characterize the postoperative outcomes and economic costs of anterior cervical discectomy and fusion (ACDF) procedures using synthetic biomechanical intervertebral cage (BC) and structural allograft (SA) implants.

OVERVIEW OF LITERATURE

ACDF is a common spine procedure that typically uses an SA or BC for the cervical fusion. Previous studies that compared the outcomes between the two implants were limited by small sample sizes, short-term postoperative outcomes, and procedures with single-level fusion.

METHODS

Adult patients who underwent an ACDF procedure in 2007-2016 were included. Patient records were extracted from MarketScan, a national registry that captures person-specific clinical utilization, expenditures, and enrollments across millions of inpatient, outpatient, and prescription drug services. Propensity-score matching (PSM) was employed to match the patient cohorts across demographic characteristics, comorbidities, and treatments.

RESULTS

Of 110,911 patients, 65,151 (58.7%) received BC implants while 45,760 (41.3%) received SA implants. Patients who underwent BC surgeries had slightly higher reoperation rates within 1 year after the index ACDF procedure (3.3% vs. 3.0%, p=0.004), higher postoperative complication rates (4.9% vs. 4.6%, p=0.022), and higher 90-day readmission rates (4.9% vs. 4.4%, p =0.001). After PSM, the postoperative complication rates did not vary between the two cohorts (4.8% vs. 4.6%, p=0.369), although dysphagia (2.2% vs. 1.8%, p<0.001) and infection (0.3% vs. 0.2%, p=0.007) rates remained higher for the BC group. Other outcome differences, including readmission and reoperation, decreased. Physician's fees remained high for BC implantation procedures.

CONCLUSIONS

We found marginal differences in clinical outcomes between BC and SA ACDF interventions in the largest published database cohort of adult ACDF surgeries. After adjusting for group-level differences in comorbidity burden and demographic characteristics, BC and SA ACDF surgeries showed similar clinical outcomes. Physician's fees, however, were higher for BC implantation procedures.

Speed and quality of interbody fusion in porous bioceramic Al2O3 and polyetheretherketone cages for anterior cervical discectomy and fusion: a comparative study

BACKGROUND

The objective of this prospective randomized monocentric study is to compare the speed and quality of interbody fusion of implanted porous Al₂O₃ (aluminium oxide) cages with PEEK (polyetheretherketone) cages in ACDF (anterior cervical discectomy and fusion).

MATERIALS AND METHODS

A total of 111 patients were enrolled in the study, which was carried out between 2015 and 2021. The 18-month follow-up (FU) was completed in 68 patients with an Al₂O₃ cage and 35 patients with a PEEK cage in one-level ACDF. Initially, the first evidence (initialization) of fusion was evaluated on computed tomography. Subsequently, interbody fusion was evaluated according to the fusion quality scale, fusion rate and incidence of subsidence.

RESULTS

Signs of incipient fusion at 3 months were detected in 22% of cases with the Al₂O₃ cage and 37.1% with the PEEK cage. At 12-month FU, the fusion rate was 88.2% for Al₂O₃ and 97.1% for PEEK cages, and at the final FU at 18 months, 92.6% and 100%, respectively. The incidence of subsidence was observed to be 11.8% and 22.9% of cases with Al₂O₃ and PEEK cages, respectively.

CONCLUSIONS

Porous Al₂O₃ cages demonstrated a lower speed and quality of fusion in comparison with PEEK cages. However, the fusion rate of Al₂O₃ cages was within the range of published results for various cages. The incidence of subsidence of Al₂O₃ cages was lower compared to published results. We consider the porous Al₂O₃ cage as safe for a stand-alone disc replacement in ACDF.

Allograft Versus Autograft in Anterior Cervical Discectomy and Fusion: A Propensity-Matched Analysis

Objective

To compare the 30-day complication rate associated with allograft versus autograft in anterior cervical discectomy and fusion (ACDF) and to determine preoperative factors that may influence complication rate.

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was retrospectively queried from 2014 to 2017 for all procedures with CPT codes for ACDF (22551). Patients undergoing ACDF with either autograft or allograft were matched by propensity scores based on age, sex, body mass index, and comorbidities. The incidence of adverse events in the 30-day postoperative period was compared.

Results

A total of 21,588 patients met the inclusion and exclusion criteria. Following the 10:1 propensity match, 17,061 remained in the study (1,551 autograft and 15,510 allograft). The overall adverse event rate was 3.18%; 3.48% for autograft and 3.15% for allograft (P=0.494). Autograft had a significantly greater incidence of extended length of stay (>2 d) (LOS) (48.9% vs 34.8%; P<0.001). Multivariate analysis suggested that autograft selection was associated with extended LOS (OR 1.4; 95% CI 1.3-1.5).

Conclusion

The results of this study provide information regarding how graft selection can relate to extended hospital LOS and influence postoperative complications. Extended LOS may be associated with worse patient outcomes and increase the overall cost of care. Further study should be performed to determine which patients would benefit from autograft versus allograft with regards to long-term outcomes, in consideration of these increased short-term complications.

Structural Allograft Versus Synthetic Interbody Cage for Anterior Cervical Discectomy and Fusion: A Comparison of 1-Year Outcomes From a National Database

STUDY DESIGN

Observational cohort study.

OBJECTIVE

To compare 1-year perioperative complications between structural allograft (SA) and synthetic cage (SC) for anterior cervical discectomy and fusion (ACDF) using a national database.

METHODS

The TriNetX Research Network was retrospectively queried. Patients undergoing initial single or multilevel ACDF surgery between October 1, 2015 and April 30, 2019 were propensity score matched based on age and comorbidities. The rates of 1-year revision ACDF surgery and reported diagnoses of pseudoarthrosis, surgical site infection (SSI), and dysphagia were compared between structural allograft and synthetic cage techniques.

RESULTS

A comparison of 1-year outcomes between propensity score matched cohorts was conducted on 3056 patients undergoing single-level ACDF and 3510 patients undergoing multilevel ACDF. In single-level ACDF patients, there was no difference in 1-year revision ACDF surgery (P = .573), reported diagnoses of pseudoarthrosis (P = .413), SSI (P = .620), or dysphagia (P = .529) between SA and SC groups. In multilevel ACDF patients, there was a higher rate of revision surgery (SA 3.8% vs SC 7.3%, odds ratio = 1.982, P < .001) in the SC group, and a higher rate of dysphagia in the SA group (SA 15.9% vs SC 12.9%).

CONCLUSION

While the overall revision and complication rate for single-level ACDF remains low despite interbody graft selection, SC implant selection may result in higher rates of revision surgery in multilevel procedures despite yielding lower rates of dysphagia. Further prospective study is warranted.

Using a mixture of local bone dust and morselized bone as graft materials in single- and double-level ACDF

Background

Using a cage filled with local bone in anterior cervical discectomy and fusion (ACDF) can eliminate morbidities associated with autograft harvest from the iliac crest while achieving high fusion rates. However, there is still no consensus regarding the methods for using local bone grafts. This retrospective study was performed to compare the clinical and radiological outcomes of using a mixture of bone dust and morselized bone versus morselized bone alone in ACDF.

Methods

A retrospective study of 228 patients affected by cervical degenerative disease who had undergone single- or double-level ACDF between January 2014 and June 2018 was performed. Nanohydroxyapatite/polyamide-66 (n-HA/PA66) combined with morselized bone was used in 111 patients (group A: single-level ACDF in 51 patients and double-level ACDF in 60 patients), whereas the n-HA/PA66 cage combined with a mixture of bone dust and morselized bone was used in 117 patients (group B: single-level ACDF in 58 patients and double-level ACDF in 59 patients). The fusion rate, extent of cage subsidence, fusion segmental height (FSH), C2-7 lordosis, segmental sagittal alignment (SSA), 10-point visual analog scale (VAS) score, and Neck Disability Index (NDI) were compared between the two groups.

Results

The VAS score and NDI were significantly reduced after the operation in group A and group B. At the final follow-up, the fusion rate was 90.2 % (46/51) and 94.8 % (55/58) in patients treated with single-level ACDF in group A and group B, respectively (p > 0.05). In patients treated with double-level ACDF, bone fusion was achieved in 52 patients (86.7 %) in group A and 55 patients (93.2 %) in group B (p > 0.05). The fusion rate of single- and double-level ACDF was higher in patients in group B than those in group A at the 3-month, 6-month and 12-month follow-ups (p < 0.05). The extent of cage subsidence after single- and double-level ACDF was lower in patients in group B (1.5 ± 0.5 mm and 2.3 ± 0.8 mm, respectively) than in those in group A (1.8 ± 0.7 mm and 2.9 ± 1.4 mm, respectively) (p < 0.05). There was no significant difference between the two groups in the C2-7 lordosis, FSH, SSA, VAS score, or NDI before or after the operation (p > 0.05).

Conclusions

Using a mixture of local bone dust and morselized bone as cage-filling materials yielded comparably good clinical outcomes as using morselized bone alone in single- and double-level ACDF. However, the mixture graft of bone dust and morselized bone was more beneficial in promoting early fusion and reducing cage subsidence.

Short Plate with Screw Angle over 20 Degrees Improves the Radiologic Outcome in ACDF: Clinical Study

BACKGROUND

Anterior cervical discectomy and fusion surgery is a common procedure for degenerative cervical spine. This describes allospacer and implant-related outcomes, comparing medium plate-low screw angle and short plate-high screw angle techniques.

METHODS

From January 2016 to June 2019, 79 patients who underwent ACDF were prospectively enrolled. Patients were divided, depending on the plate-screw system used: medium plate-low screw angle (12.3 ± 2.5 to 13.2 ± 3.2 degrees), and short plate-high screw angle (22.8 ± 5.3 to 23.3 ± 4.7 degrees). Subsidence, ALOD, and sagittal cervical balance were analyzed using lateral cervical X-rays. NDI and VAS scores were also evaluated.

RESULTS

Age for medium plate-low-angled screw group is 58.0 ± 11.3 years, and 55.3 ± 12.0 in the short plate-high-angled screw group (p-value = 0.313). Groups were comparable in mean NDI (p-value = 0.347), VAS (p-value = 0.156), C2-C7 SVA, (p-value = 0.981), and lordosis angle (p-value = 0.836) at 1-year post-surgery. Subsidence was higher in the medium plate-low-angled screw than in the short plate-high-angled screw (25% and 8.5%, respectively, p-value = 0.045). ALOD is also more common in the medium plate group (p-value = 0.045).

CONCLUSION

Use of a short plate and insertion of high-angled screws (more than 20 degrees) has less chance of subsidence and occurrence of ALOD than the traditional technique of using medium plate and low angle.

Analysis of the Variables Affecting the Incidence, Location, and Severity of Cage Subsidence Following Anterior Cervical Discectomy and Fusion Operation

BACKGROUND

For surgical management of degenerative cervical spine disease with myeloradiculopathy, stand-alone cages are frequently used in 1- and 2-level anterior cervical discectomy and fusion (ACDF) operations with a paucity of literature on factors influencing cage subsidence. The aim of this study was to analyze the variables affecting the incidence, location, and severity of cage subsidence.

METHODS

Retrospective review of prospectively collected data of 77 patients (95 levels) undergoing ACDF surgery was conducted. Variables analyzed were age, gender, sagittal alignment, maximum disc height (superior, inferior, and procedure levels), cage size, shape, location, degree of subsidence (minor <2 mm, mild 2-4 mm, moderate 5-7.5 mm, severe >7.5 mm) and location of subsidence.

RESULTS

The incidence of cage subsidence was 34% (32 levels), and 91% were minor or mild. Significantly lower mean maximum height of the inferior disc compared to the nonsubsidence group (5.17 versus 5.96; P = 0.0025) was recorded. Significantly greater incidence of subsidence (40%) was recorded in patients with abnormal cervical spine alignment (focal or diffuse kyphosis) versus 18% with normal alignment (P = 0.02). Greater incidence of subsidence was recorded with more anterior positioned cages (52%; p=0.01). No statistical significance was found for age, gender, superior disc height, or cage shape/size.

CONCLUSIONS

Greater incidence of cage subsidence is significantly associated with a lower maximum disc height of the disc below the operated level (<5.5 mm), abnormal sagittal alignment, and more anteriorly positioned cages. We found that the vast majority of cage subsidence was focal, minor to mild, without having any immediate or late clinical implications in terms of need for revision surgery.

Anterior Cervical Arthrodesis With Polyetheretherketone Spacers: What is the Role of the Grafting Material?

STUDY DESIGN

This was a retrospective study of 2 surgeons' use of a single polyetheretherketone (PEEK) device.

OBJECTIVE

Our objective was to investigate the fusion adjunct placed within PEEK devices to examine the likelihood of an arthrodesis, regardless of the PEEK interbody device itself.

SUMMARY OF BACKGROUND DATA

The effectiveness of PEEK interbody devices in anterior cervical arthrodesis has been questioned.

METHODS

The authors retrospectively reviewed the results of 121 patients with demineralized bone matrix (DBM) and 96 with local autograft bone placed within identical PEEK devices for anterior cervical arthrodesis (from 2011 to 2018); 1 surgeon used DBM and another local autograft bone. Arthrodesis was determined independently by a surgeon and 2 blinded neuroradiologists.

RESULTS

For DBM versus autograft; mean age was 60 versus 61 years, smoking status 42.1% versus 31%, diabetes mellitus 18.2% versus 28%, mean body mass index 31 versus 30, and follow up averaged 17 months in both groups. For DBM versus autograft; a radiographic arthrodesis was observed in 22.3% versus 76% of patients. Refusion at the index level was required in 5.8% of the DBM and 0% of the autograft patients.

CONCLUSIONS

A PEEK interbody device filled with local autograft resulted in a higher radiographic fusion rate and a lower need for reoperation at the index level than an identical device filled with DBM. Caution is warranted in assigning fusion failure to the PEEK device alone in anterior cervical discectomy and fusion surgery.

PEEK interbody devices for multilevel anterior cervical discectomy and fusion: association with more than 6-fold higher rates of pseudarthrosis compared to structural allograft

OBJECTIVE

Common interbody graft options for anterior cervical discectomy and fusion (ACDF) include allograft and polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucent properties and a modulus of elasticity similar to that of bone. PEEK devices also result in higher billing costs than allograft, which may drive selection. A previous study found a 5-fold higher rate of pseudarthrosis with the use of PEEK devices compared with structural allograft in single-level ACDF. Here the authors report on the occurrence of pseudarthrosis with PEEK devices versus structural allograft in patients who underwent multilevel ACDF.

METHODS

The authors retrospectively reviewed 81 consecutive patients who underwent a multilevel ACDF and had radiographic follow-up for at least 1 year. Data were collected on age, sex, BMI, tobacco use, pseudarthrosis, and rate of reoperation for pseudarthrosis. Logistic regression was used for data analysis.

RESULTS

Of 81 patients, 35 had PEEK implants and 46 had structural allograft. There were no significant differences between age, sex, smoking status, or BMI in the 2 groups. There were 26/35 (74%) patients with PEEK implants who demonstrated radiographic evidence of pseudarthrosis, compared with 5/46 (11%) patients with structural allograft (p < 0.001, OR 22.2). Five patients (14%) with PEEK implants required reoperation for pseudarthrosis, compared with 0 patients with allograft (p = 0.013).

CONCLUSIONS

This study reinforces previous findings on 1-level ACDF outcomes and suggests that the use of PEEK in multilevel ACDF results in statistically significantly higher rates of radiographic pseudarthrosis and need for revision surgery than allograft. Surgeons should consider these findings when determining graft options, and reimbursement policies should reflect these discrepancies.

Comparison of the effectiveness and safety of bioactive glass ceramic to allograft bone for anterior cervical discectomy and fusion with anterior plate fixation

Recently, a bioactive glass ceramic (BGC) has been developed for use as intervertebral cages for anterior cervical discectomy and fusion (ACDF). However, the effectiveness and safety of BGC cages remain to be evaluated. We completed a retrospective comparison of the radiological and clinical outcomes of 36 patients (52 levels) who underwent ACDF with a BGC cage and 35 patients (54 levels) using allograft bone. The following variables were compared between the two groups: the visual analog (VAS) neck and arm pain score and the neck disability index (NDI), measured before surgery and 1 year after; the change in Cobb's angle, between the C2 and C7 vertebrae, the global sagittal angle, and disc height compared from before surgery to 1 year after; and the rate of spinal fusion and cage subsidence at 1 and 2 years after surgery. The VAS and NDI scores were not different between the two groups. Similarly, the spinal fusion rate was not different between the BGC and allograft bone group at 1 year (73% and 87%, respectively; p = 0.07) and 2 years (94% and 91%, respectively; p = 0.54) after surgery. However, the rate of cage subsidence was higher in the allograft bone (43%) than the BGC (19%) group (p = 0.03), as was the rate of instrument-related failure (p = 0.028), with a specifically higher incidence of implant fracture or failure in the allograft bone group (p = 0.025). Overall, our findings indicate that BGC cages provide a feasible and safe alternative to allograft bone for ACDF.

Escherichia coli BMP-2 showed comparable osteoinductivity with Chinese hamster ovary derived BMP-2 with demineralized bone matrix as carrier

Escherichia coli bone morphogenetic protein-2 (ErhBMP-2) had a larger yield but less osteoinductivity than Chinese hamster ovary cell bone morphogenetic protein-2 (CrhBMP-2). Since the release profile of rhBMP-2 affects its osteoinductivity, an appropriate carrier could improve the effect of ErhBMP-2. Demineralized bone matrix (DBM) was one of the most widely used bone substitutes, but few studies evaluated the osteoinductivity of ErhBMP-2 while it was carried by DBM. Therefore, we compared the osteoinductivity of ErhBMP-2 with CrhBMP-2 with DBM as the carrier of each. In vitro results showed ErhBMP-2 had slightly less osteoinductivity than CrhBMP-2. However, with DBM as the carrier, ErhBMP-2 induced significantly more bone regeneration in rat calvaria defects. Therefore, ErhBMP-2 might have comparable osteoinductivity with CrhBMP-2 while carried by DBM.

Integral Fixation Titanium/Polyetheretherketone Cages for Cervical Arthrodesis: Evolution of Cage Design and Early Radiological Outcomes and Fusion Rates

Objective

To evaluate the initial outcomes of a composite cage with integral fixation using the Redmond titanium (Ti)/polyetheretherketone (PEEK) anterior cervical discectomy and fusion (ACDF) device.

Methods

Data from 50 consecutive patients were prospectively collected from a single senior surgeon cohort. All cages were between 5 and 8 mm in height, and were packed with supercritical CO₂ sterilized allograft. Patients were followed up for a minimum of 6 months, and implant complications were assessed.

Results

From the original cohort, three were unavailable for follow‐up. Forty‐seven patients with a total of 58 operative levels were observed for a mean of 7.9 months. A fusion rate of 96% was achieved. Good to excellent outcomes were seen in 92% of patients. There were no cases of implant Ti/PEEK delamination or implant failure, with excellent early fusion rates using supercritical CO₂ allograft.

Conclusions

The present study demonstrates the development of a composite ACDF cage design that is a safe and effective treatment option with the potential for early osseointegration and interbody fusion. Supercritical CO₂ sterilized allograft was an effective graft material supporting fusion.

Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion

In BriefThe authors examined fusion rates after single-level anterior cervical discectomy and fusion, comparing use of a structural allograft with use of polyetheretherketone (PEEK) interbody devices packed with bone graft. The results demonstrate superior results of structural allograft in terms of arthrodesis rates and reoperation rates. Currently, reimbursement rates substantially favor the use of PEEK and other synthetic devices, which the authors believe should be changed based on the results of this study.

A single center retrospective clinical evaluation of anterior cervical discectomy and fusion comparing allograft spacers to silicon nitride cages

BACKGROUND

Iliac crest autograft or allograft spacers have been traditionally utilized in anterior cervical discectomy and fusion (ACDF) to provide vertebral stabilization and enhanced osteogenesis. However, abiotic cages have largely replaced these allogenic sources due to host-site morbidities and disease transmission risks, respectively. Although devices made of polyetheretherketone (PEEK) or titanium-alloys (Ti) have gained wide popularity, they lack osteoinductive or conductive capabilities. In contrast, silicon nitride (Si3N4) is a relatively new implant material that also provides structural stability and yet purportedly offers osteopromotive and antimicrobial behavior. This study compared radiographic outcomes at ≥12 months of follow-up for osseous integration, fusion rate, time to fusion, and subsidence in ACDF patients with differing intervertebral spacers.

METHODS

Fifty-eight ACDF patients (108 segments) implanted with Si3N4 cages were compared to thirty-four similar ACDF patients (61 segments) implanted with fibular allograft spacers. Lateral radiographs (normal, flexion, and extension) were obtained at 3, 6, 12, and 24 months to assess osseous integration, the presence of bridging bone, the absence of peri-implant radiolucencies, subsidence, and fusion using both interspinous distance (ISD) and Cobb angle methods.

RESULTS

In patients with ≥12 months of follow-up, fusion for the allograft spacers and Si3N4 cages was 86.84% and 96.83%, respectively (ISD method, P=0.10), and 67.65% and 84.13%, respectively (Cobb angle method P=0.07), while osseointegration was 76.32% and 93.65%, respectively (P=0.02). The time to fusion significantly favored the Si3N4 cages (4.08 vs. 8.64 months (ISD method, P=0.01), and 6.76 vs. 11.74 months (Cobb angle method, P=0.04). The assessed time for full osseointegration was 7.83 and 19.24 months for Si3N4 and allograft, respectively (P=0.00). Average subsidence at 1-year follow-up was 0.51 and 2.71 mm for the Si3N4 and allograft cohorts, respectively (P=0.00).

CONCLUSIONS

In comparison to fibular allograft spacers, Si3N4 cages showed earlier osseointegration and fusion, higher fusion rates, and less subsidence.

Pain Management After Bone Reconstruction Surgery Using an Analgesic Bone Cement: A Functional Noninvasive In Vivo Study Using Gait Analysis

Postoperative pain after bone reconstruction is a serious complication that could jeopardize the global success of a surgery. This pain must be controlled and minimized during the first 3 to 4 postoperative days to prevent it from becoming chronic. In this study, a critical-size bone defect was created at the femoral distal end of rats and filled by an injectable calcium phosphate cement (CPC) loaded or not with local anesthetics (bupivacaine or ropivacaine). A functional evaluation of the gait was performed using the CatWalk system to compare the postoperative pain relief enhanced by the different CPCs after such a bone filling surgery. The results demonstrated significant pain relief during the short-term postoperative period, as shown by the print area and intensity parameters of the operated paw. At 24hours, the print area decreased by 65%, 42%, and 24%, and the intensity decreased by 25%, 9%, and 1% for unloaded, ropivacaine-loaded, and bupivacaine-loaded CPCs, respectively, compared with the preoperative values. Bupivacaine-loaded CPC provided an earlier return to full functional recovery than ropivacaine-loaded CPC. Moreover, the CPCs retained their biologic and mechanical properties. For all these reasons, anesthetic-loaded CPCs could be part of the global pain management protocol after bone reconstruction surgery such as iliac crest bone grafting procedures.

PERSPECTIVE

Bupivacaine-loaded CPC provided an earlier return to full gait function than ropivacaine-loaded CPC, with preserved bone filling properties. Such analgesic CPCs deserve further in vivo investigation and may be part of the global pain management protocol after bone reconstruction or bone augmentation surgery such as iliac crest bone grafting.

Local delivery of a novel PTHrP via mesoporous bioactive glass scaffolds to improve bone regeneration in a rat posterolateral spinal fusion model

With the development of tissue engineering, bone defects, such as fractured long bones or cavitary lesions, may be efficiently repaired and reconstructed using bone substitutes. However, high rates of fusion failure remain unavoidable in spinal fusion surgery owing to the lack of appropriate materials for bone regeneration under such challenging conditions. Parathyroid hormone (PTH), a major regulator of bone remodeling, exerts both anabolic and catabolic effects. In this study, we modified PTH(1-34) and designed and synthesized a novel PTH-related peptide, namely PTHrP-1. Further, we fabricated a local PTHrP delivery device from mesoporous bioactive glass (MBG) to address the need for a suitable material in spinal fusion surgery. Using MBG scaffolds as a control, the biological properties of PTHrP-MBG scaffolds were evaluated in terms of attachment, proliferation, and alkaline phosphatase activity, as well as osteogenic gene and angiogenic gene expression in co-cultured rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. Furthermore, PTHrP-1-MBG scaffolds were tested in a rat posterolateral spinal fusion model. Our data showed that PTHrP-1-MBG scaffolds possessed good ability to facilitate attachment and stimulation of rBMSC proliferation and differentiation. Importantly, the in vivo results revealed that the PTHrP-1-MBG scaffolds facilitated faster new bone formation and a higher rate and quality of spinal fusion. Therefore, the results suggest that devices consisting of the present novel PTHrP and MBG possess wider potential applications in bone regeneration and should serve as a promising bone substitute for spinal fusion.

Relationship between depression and clinical outcome following anterior cervical discectomy and fusion

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure for patients with symptomatic degenerative conditions of the cervical spine. The objective is to assess the impact of preoperative depression and other baseline characteristics on patient reported clinical outcomes following ACDF surgery based on the experience at our institution.

METHODS

This was a retrospective cohort study of some patients undergoing ACDF at a single institution from 2012 to 2014. Ninety-three patients that underwent an ACDF procedure were included. The primary outcome measure was post-operative Nurick score.

RESULTS

Sixteen (17.2%) patients had a formal diagnosis of depression compared to 77 (82.8%) patients without depression. On univariate analysis, patients with depression had statistically significantly higher Nurick scores compared to patients without depression after surgery (coefficient =0.55, 95% CI: 0.21-0.90, P=0.002). On multivariate analysis, there was a trend toward higher postoperative Nurick scores in patients that had depression (coefficient =0.31, 95% CI: -0.01-0.63, P=0.057).

CONCLUSIONS

This small retrospective study reveals an inverse relationship between preoperative depression and functional outcome. Further research should be performed to investigate this relationship and to investigate if treating depression can improve postoperative outcomes.

Smith-Robinson procedure with and without Caspar plating as a treatment for cervical spondylotic myelopathy: A 26-year follow-up of 23 patients

PURPOSE

The purpose of this study was to assess long-term follow-up data after anterior cervical decompression and fusion (ACDF) with and without Caspar plating (ACDF + PS) for the treatment of cervical spondylotic myelopathy (CSM) with special focus on functional outcome, pain, and repeat surgery for adjacent segment disease (ASD).

METHOD

Hospital records of 45 patients who were affected by CSM and underwent ACDF or ACDF + PS at least 17 years ago were reviewed. Information about diagnosis, surgical report, pre- and postoperative clinical process, and complications was analyzed. Clinical outcome was assessed using a standardized questionnaire including the Neck Disability Index (NDI), modified JOA-score, Odom's criteria, limitations in quality of life, and questions about the current neurological status and pain.

RESULTS

Twenty-three patients with a mean follow-up of 26 years were evaluated. ACDF was performed in nine and ACDF + PS in 14 patients, respectively. At follow-up 78.3% of patients were free of pain, 91.3% had no motor deficit, 73.9% had no sensory deficit, and 60.7% had no gait disturbance. The current mean NDI is 14% (range 2-44%), the mean modified JOA-score was 17.2 (range 15-18). According to Odom's criteria 78.3% of patients had clinical success. In four patients repeat surgery was indicated due to pseudarthrosis or symptomatic ASD (17.4%).

CONCLUSIONS

ACDF and ACDF + PS yield significant decrease in neck pain, a significant increase in sensorimotor function and a high rate of clinical success. Patients with preoperative gait disturbance completely recovered in about 60% of cases. Overall prevalence for ASD was 17.4% after 25 years.