Minimum four-year subsequent surgery rates of cervical disc replacement versus fusion: A meta-analysis of prospective randomized clinical trials

Comparing outcomes between anterior cervical disc replacement (ACDR) and minimally invasive posterior cervical foraminotomy (MI-PCF) in the treatment of cervical radiculopathy

BACKGROUND CONTEXT

Anterior cervical disc replacement (ACDR) and minimally invasive posterior cervical foraminotomy (MI-PCF) have emerged as two increasingly popular alternatives to anterior cervical discectomy and fusion (ACDF) for the management of cervical radiculopathy. Both techniques provide advantages of segmental motion preservation and lower rates of adjacent segment degeneration (ASD) compared to ACDF.

PURPOSE

The purpose of this study was to analyze the clinical and functional outcomes of patients undergoing ACDR or MI-PCF for the treatment of unilateral cervical radiculopathy.

STUDY DESIGN/SETTING

Retrospective Cohort Review.

PATIENT SAMPLE

A total of 152 patients were included (86 ACDR and 66 MI-PCF).

OUTCOME MEASURES

(1) Patient demographics; (2) perioperative data; (3) rates of complications and revisions; (5) visual analogue scale (VAS) and Neck Disability Index (NDI) scores.

METHODS

A retrospective cohort review was performed to identify all patients at a single institution between 2012-2020 who underwent 1- or 2- level ACDR or MI-PCF from C3-C7 with a minimum follow-up of 24 months. Patient demographics, perioperative data, postoperative complications, and revisions were analyzed. Patient reported outcome measures including VAS and NDI scores were compared.

RESULTS

The ACDR group had a significantly greater mean operative time (99.8 minutes vs 79.2 minutes, p<.001), but comparable estimated blood loss and length of stay following surgical intervention (p=.899). The overall complication rate was significantly greater in the ACDR group than the MI-PCF group (24.4% vs 6.2%; p=.003) but was largely driven by approach-related dysphagia in 20.9% of ACDR patients. The MI-PCF group had significantly greater revision rates (13.6% vs 1.2%; p=.002) with an average time to revision of 20.7 months in the MI-PCF group compared to 40.3 months in the ACDR group. The ACDR cohort had significantly greater improvements in NDI scores at the final follow-up (25.0 vs 21.3, p<.001).

CONCLUSION

Our results suggest that ACDR offer clinically relevant advantages over MI-PCF in terms of long-term revision rates despite an increased approach-related risk of transient postoperative dysphagia. Additionally, patients in the ACDR cohort achieved greater mean improvements in NDI scores but these results may have limited clinical significance due to inability to reach minimally clinically important difference (MCID) thresholds.

An additively manufactured model for preclinical testing of cervical devices

Purpose

Composite models have become commonplace for the assessment of fixation and stability of total joint replacements; however, there are no comparable models for the cervical spine to evaluate fixation. The goal of this study was to create the framework for a tunable non-homogeneous model of cervical vertebral body by identifying the relationships between strength, in-fill density, and lattice structure and creating a final architectural framework for specific strengths to be applied to the model.

Methods

The range of material properties for cervical spine were identified from literature. Using additive manufacturing software, rectangular prints with three lattice structures, gyroid, triangle, zig-zag, and a range of in-fill densities were 3D-printed. The compressive and shear strengths for all combinations were calculated in the axial and coronal planes. Eleven unique vertebral regions were selected to represent the distribution of density. Each bone density was converted to strength and subsequently correlated to the lattice structure and in-fill density with the desired material properties. Finally, a complete cervical vertebra model was 3D-printed to ensure sufficient print quality.

Results

Materials testing identified a relationship between in-fill densities and strength for all lattice structures. The axial compressive strength of the gyroid specimens ranged from 1.5 MPa at 10% infill to 31.3 MPa at 100% infill and the triangle structure ranged from 2.7 MPa at 10% infill to 58.4 MPa at 100% infill. Based on these results, a cervical vertebra model was created utilizing cervical cancellous strength values and the corresponding in-fill density and lattice structure combination. This model was then printed with 11 different in-fill densities ranging from 33% gyroid to 84% triangle to ensure successful integration of the non-homogeneous in-fill densities and lattice structures.

Conclusions

The findings from this study introduced a framework for using additive manufacturing to create a tunable, customizable biomimetic model of a cervical vertebra.

Cervical Total Disc Replacement: Expanded Indications

Cervical total disc replacement (cTDR) is now a firm alternative to anterior cervical discectomy and fusion (ACDF) for degenerative disc disease (DDD). Robust level 1 data from Federal Drug Administration-approved clinical trials demonstrated that cTDR is in any case equally safe and effective compared with ACDF for 1- or 2-level DDD. Furthermore, from early postoperative to long-term follow-up of 10 to 15 years, cTDR rates superiorly in many primary clinical outcomes. According to the published literature, at least nine different cTDR devices share this consistent pattern. On the other hand, the surgical treatment of more than 2-level disc disease is haunted by an elusive paradox. It is easily understandable that 3- and 4-level ACDF, with the well-known associated limitations, is not the superlative intervention for a spine segment anatomically designed to provide motion, as cervical spine is. Furthermore, multilevel ACDF exacerbates many of the clinical and biomechanical complications related with single-level fusion. However, as cTDR is not immaculate of constraints and failures, its clinical safety and efficacy and cost-effectiveness in multilevel anterior compressive pathology need to be established. This article analyses the current available evidence supporting the expanded indication of cTDR to 3- and 4-level disc disease, either stand-alone or adjacent to fusion, from a less stringent European perspective.

Mid- to long-term rates of symptomatic adjacent-level disease requiring surgery after cervical total disc replacement compared with anterior cervical discectomy and fusion: a meta-analysis of prospective randomized clinical trials

Background

Thus far, no meta-analysis focusing on the mid- to long-term incidence of adjacent segment disease requiring surgery after cervical total disc replacement and anterior cervical discectomy and fusion has been published yet. This study aimed to compare mid- to long-term rates of symptomatic adjacent-level disease requiring surgery after cervical disc replacement and anterior cervical fusion.

Methods

A meta-analysis was performed, and only randomized controlled trials with a follow-up period of more than 48 months reporting rates of symptomatic adjacent-level disease requiring surgery after cervical total disc replacement and anterior cervical discectomy and fusion were included.

Results

The analysis revealed that the overall rate of symptomatic adjacent-level disease requiring surgery in the cervical disc replacement group was significantly lower than that of the anterior cervical fusion group at 48–120 months’ follow-up. The subgroup analysis of different follow-up periods also yielded the same results. The rate of symptomatic adjacent-level disease requiring surgery in the cervical disc replacement group using unrestricted prosthesis was significantly lower than that of the anterior cervical fusion group (p < 0.001); however, the cervical disc replacement group using semi-restricted prosthesis showed no statistical difference compared with the fusion group.

Conclusions

Our review suggests that cervical disc replacement is preferable to anterior cervical fusion in reducing the incidence of symptomatic adjacent-level disease requiring surgery at mid- to long-term follow-up. A review of the literature also demonstrated that randomized controlled trials investigating the rate of symptomatic adjacent-level disease requiring surgery were insufficient; therefore, studies focusing on this subject with longer-term follow-up are warranted.

Cervical Disc Replacement: Trends, Costs, and Complications

Study Design

Retrospective review of insurance database.

Purpose

To investigate national trends, complications, and costs after cervical disc replacement (CDR) using an administrative insurance database representative of the United States population.

Overview of Literature

As CDR continues to be used to treat patients with cervical stenosis, it is important to gain a better understanding of its use on a national level, potential complications, and cost. This information will allow for optimal patient counseling, risk stratification, and healthcare cost assessments. Several prior studies have investigated complications associated with CDR, but they have been limited by small sample size, single institution experiences, limited follow-up, and potential conflicts of interest.

Methods

Patients who underwent single or multilevel CDR between 2007 and 2015 were identified using an insurance database. We collected data on annual trends, reimbursement costs, patient demographic information, hospital information, and information on complications from the time of operation to 1 year postoperative.

Results

Total of 293 patients underwent either single or multilevel CDR. The number of procedures increased nonlinearly over time at an average of 17% per year, with a greater increase seen in the outpatient setting. Less than 3.7% of patients had new onset pain within 1 year after CDR. Within 1 year, 12.3% of patients reported a mechanical and/or bone-related complication. There were no patients who indicated a new nerve injury within 6 months of follow-up. Less than 3.7% of patients presented with dysphagia or dysphonia within 6 months, infection within 3 months, or a revision or reoperation within 1 year. Average reimbursement for single-level inpatient versus outpatient CDR was US $33,696.28 and US $34,675.12, respectively (p=0.29).

Conclusions

This study demonstrated that the use of CDR continued to increase. The most common complication was mechanical and/or bone-related, and cost analysis demonstrated no significant difference between inpatient and outpatient CDR.

Effect of Myelopathy on Early Clinical Improvement After Cervical Disc Replacement: A Study of a Local Patient Cohort and a Large National Cohort

Objective

Cervical disc replacement (CDR) is an effective long-term treatment for both cervical radiculopathy and myelopathy. However, there may be unique differences in the early postoperative clinical improvement for patients with and without myelopathy. In addition, previous studies using CDR to treat cervical myelopathy were underpowered to determine risk factors for relatively postoperative medical complications.

Methods

Two different cohorts were studied. A local cohort of patients undergoing CDR by a single surgeon was utilized to study the early postoperative course of clinical improvement. In addition, a national cohort of patients undergoing CDR in the 2015 and 2016 National Surgical Quality Improvement Program database was utilized to study differences in postoperative medical complications after CDR. Patients with a preoperative diagnosis of cervical myelopathy were identified in both cohorts, and perioperative outcomes and complications were compared to patients without myelopathy.

Results

A total of 43 patients undergoing CDR were included in the institutional cohort, of those 16 patients (37% of cohort) had a preoperative diagnosis of cervical myelopathy. A total of 3,023 patients undergoing CDR were included in the national cohort, of those 411 (13% of cohort) had a preoperative diagnosis of cervical myelopathy. In the institutional cohort, the nonmyelopathy group had a lower initial Neck Disability Index (NDI) and saw a faster improvement in NDI by 2 weeks postoperative. However, at 24 weeks there was no significant difference between groups in terms of NDI. Interestingly, only the nonmyelopathy cohort had a significant improvement in modified Japanese Orthopaedic Association score by 6 weeks (p<0.05). In the national cohort, myelopathy was associated with longer operative time and length of stay (p<0.05). However, there was no significant difference in perioperative complications (p>0.05) between myelopathy and nonmyelopathy patients.

Conclusion

Significant improvements in NDI, visual analogue scale (VAS)-arm pain, and VAS-neck pain are seen in both myelopathy and nonmyelopathy populations undergoing CDR by 6 weeks postoperatively. However, nonmyelopathy populations improve faster by 2 weeks postoperatively. In the national cohort analysis, medical complications were similarly low in both myelopathy and nonmyelopathy groups.

Superiority of 2-Level Total Disk Replacement Using a Cervical Disk Prosthesis Versus Anterior Cervical Diskectomy and Fusion

The purpose of this study was to evaluate the superiority of total disk replacement (TDR) using a cervical disk prosthesis vs anterior cervical diskectomy and fusion (ACDF). Ninety-six patients with a diagnosis of degenerative disk disease with radiculopathy or myeloradiculopathy at 2 contiguous levels from C-3 to C-7 were randomly allocated to the TDR group (n=48) or the ACDF group (n=48). Outcome measures were recorded preoperatively and 1 week and 3, 6, 12, 24, and 81 months postoperatively. A total of 80 patients completed the follow-up, including 38 in the TDR group and 42 in the ACDF group. Japanese Orthopaedic Association, visual analog scale, and Neck Disability Index scores showed statistically significant improvement from baseline in both groups. Moreover, compared with the TDR group, the ACDF group had statistically greater visual analog scale scores from 12 months and Neck Disability Index scores from 3 months. Compared with the ACDF group, the TDR group had statistically greater range of motion at both the superior and the inferior treated levels at 3, 6, 12, 24, and 81 months postoperatively. Compared with the TDR group, the ACDF group had statistically greater range of motion at the superior adjacent levels at 6, 12, 24, and 81 months and at the inferior adjacent levels at 24 and 81 months postoperatively. The occurrence of adjacent-segment degeneration at both the superior and the inferior adjacent levels was greater in the ACDF group than in the TDR group. Total disk replacement was safe and effective and a statistically superior alternative to ACDF for degenerative disk disease at 2 contiguous levels. It could reduce the occurrence of adjacent-segment degeneration at the superior and the inferior adjacent segments by reducing the range of motion. [Orthopedics. 2018; 41(6):344-350.].

Clinical and Radiologic Features of 3 Reconstructive Procedures for the Surgical Management of Patients with Bilevel Cervical Degenerative Disc Disease at a Minimum Follow-Up Period of 5 Years: A Comparative Study

OBJECTIVE

To assess the mid-long-term follow-up of the safety and efficacy of anterior cervical discectomy and fusion (ACDF), cervical artificial disc replacement (CADR) and hybrid surgery (HS) for bilevel cervical degenerative disc disease (cDDD).

METHODS

77 patients who underwent ACDF, HS, and CADR were retrospectively reviewed. Clinical effects were evaluated based on Neck Disability Index (NDI), Visual Analog Scale (VAS), and Japanese Orthopedic Association (JOA) scores and the Odom criteria. Radiographic outcomes were evaluated, including cervical range of motion (ROM), ROM in the operative and adjacent segments, incidence of degeneration in the adjacent segments (ASD), and heterotopic ossification (HO).

RESULTS

NDI, VAS, and JOA scores significantly improved in all patients after surgery without significant differences between groups. The excellent-to-good ratio in the Odom scale was 28/30 for the HS group, 30/33 for the ACDF group, and 13/14 for the CADR group. No significant differences in clinical outcomes or complication were found between groups (P > 0.05). Furthermore, the HS and CADR groups had less decreased ROM in the cervical and operative segments and less compensatory ROM in adjacent segments (P < 0.05). By contrast, the ACDF group had decreased ROM in the cervical and operative segments and significantly increased ROM in adjacent segments (P < 0.05). Moreover, the incidence of ASD was higher in the ACDF group, but the difference was not statistically significant (P > 0.05). HO was found in 10 patients (33.3%) in the HS group and 5 patients (35.7%) in the CADR group.

CONCLUSION

HS was superior to ACDF with regard to equivalent clinical outcomes in the mid-long-term follow-up. Furthermore, HS was superior in the maintenance of ROM and had less impact on its adjacent segments. The efficacy of HS is similar to that of CADR.

Indirect meta-analysis comparing clinical outcomes of total cervical disc replacements with fusions for cervical degenerative disc disease

Anterior cervical discectomy and fusion (ACDF) and total cervical disc replacement (TDR) are considered effective treatments for patients with cervical degenerative disc disease (CDDD). An indirect meta-analysis including 19 randomized controlled trials (5343 patients) was conducted to compare the clinical outcomes of ACDF with TDR. Primary outcomes including functional indicators (NDI [neck disability index] score, neurological success and patient satisfaction), secondary outcomes including surgical outcomes (operation time, blood loss and length of stay) and secondary surgical procedures (secondary surgery at an adjacent level, secondary surgery at the index level, secondary surgery at both levels, removal, reoperation, revision and supplemental fixation) were included in the study. TDR using the Bryan disc was associated with a greater improvement in NDI score than ACDF (MD = -5.574, 95% CrIs [credible intervals] -11.73--0.219). For neurological success, the Bryan (odds ratio [OR] = 0.559, 95% CrIs 0.323-0.955) and Prestige (OR = 0.474, 95% CrIs 0.319-0.700) discs were superior to ACDF. However, no differences in the patient satisfaction rate were shown between TDR and ACDF. For patients with CDDD, ACDF using allograft and a plate is most effective for determining the surgical parameters. Moreover, TDR using the ProDisc-C, Mobi-C, Prestige and Bryan discs are good choices for improving functional outcomes and reducing secondary surgeries.