Pseudarthrosis in anterior cervical discectomy and fusion with a self-locking, stand-alone cage filled with hydroxyapatite

J Neurosurg Spine 33:717–726, 2020

The goal of this study was to evaluate the incidence of pseudarthrosis after the treatment of cervical degenerative disc disease (CDDD) with anterior cervical discectomy and fusion (ACDF) in which self-locking, stand-alone intervertebral cages filled with hydroxyapatite were used.

METHODS The authors performed a retrospective cohort study of 49 patients who underwent 1- to 3-level ACDF with self-locking, stand-alone intervertebral cages without plates, with a minimum 2 years of follow-up. The following data were extracted from radiological and clinical charts: age, sex, time and type of pre- and postoperative signs and symptoms, pain status (visual analog scale [VAS]), functional status (Neck Disability Index [NDI]), history of smoking, bone quality (bone densitometry), and complications. Pseudarthrosis was diagnosed by a blinded neuroradiologist using CT scans. Clinical improvement was assessed using pre- and postoperative comparison of VAS and NDI scores. The Wilcoxon test for paired tests was used to evaluate statistical significance using a p value of < 0.05.

RESULTS Three patients (6%) developed symptomatic pseudarthrosis requiring reoperation, with only 1 patient showing clinical worsening due to pseudarthrosis, while the other 2 with pseudarthrosis had associated disc disease at an adjacent level. The rate of symptomatic pseudarthrosis according to the number of operated levels was 0% for 1 level, 8.7% (2/23 patients) for 2 levels, and 7.7% (1/13 patients) for 3 levels. The total pseudarthrosis rate (including both symptomatic and asymptomatic patients) was 16.4%. Considering the clinical outcomes, there was a significant improvement of 75.6% in neck pain and 95.7% in arm pain, as well as a 64.9% improvement in NDI scores. Complications were observed in 18.4% of patients, with adjacent-level degenerative disease being the most prevalent at 14.3%.

CONCLUSIONS ACDF with self-locking, stand-alone cages filled with a hydroxyapatite graft can be used for the surgical treatment of 1- to 3-level CDDD with clinical and radiological outcomes significantly improved after a minimum 2-year follow-up period. Comparative studies are necessary.

 

Two-level cervical disc arthroplasty versus anterior cervical discectomy and fusion: 10-year outcomes of a prospective, randomized investigational device exemption clinical trial

J Neurosurg Spine 31:508–518, 2019

The authors assessed the 10-year clinical safety and effectiveness of cervical disc arthroplasty (CDA) to treat degenerative cervical spine disease at 2 adjacent levels compared to anterior cervical discectomy and fusion (ACDF).

METHODS A prospective, randomized, controlled, multicenter FDA-approved clinical trial was conducted comparing the low-profile titanium ceramic composite–based Prestige LP Cervical Disc (n = 209) at two levels with ACDF (n = 188). Ten-year follow-up data from a postapproval study were available on 148 CDA and 118 ACDF patients and are reported here. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at regular postoperative follow-up intervals for up to 10 years. The primary endpoint was overall success, a composite variable that included key safety and efficacy considerations. Ten-year follow-up rates were 86.0% for CDA and 84.9% for ACDF.

RESULTS From 2 to 10 years, CDA demonstrated statistical superiority over ACDF for overall success, with rates at 10 years of 80.4% versus 62.2%, respectively (posterior probability of superiority [PPS] = 99.9%). Neck Disability Index (NDI) success was also superior, with rates at 10 years of 88.4% versus 76.5% (PPS = 99.5%), as was neurological success (92.6% vs 86.1%; PPS = 95.6%). Improvements from preoperative results in NDI and neck pain scores were consistently statistically superior for CDA compared to ACDF. All other study effectiveness measures were at least noninferior for CDA compared to ACDF through the 10-year follow-up period, including disc height. Mean angular ranges of motion at treated levels were maintained in the CDA group for up to 10 years. The rates of grade IV heterotopic ossification (HO) at the superior and inferior levels were 8.2% and 10.3%, respectively. The rate of severe HO (grade III or IV) did not increase significantly from 7 years (42.4%) to 10 years (39.0%). The CDA group had fewer serious (grade 3–4) implantrelated or implant/surgical procedure–related adverse events (3.8% vs 8.1%; posterior mean 95% Bayesian credible interval [BCI] of the log hazard ratio [LHR] -0.92 [-1.88, -0.01]). The CDA group also had statistically fewer secondary surgical procedures at the index levels (4.7%) than the ACDF group (17.6%) (LHR [95% BCI] -1.39 [-2.15, -0.61]) as well as at adjacent levels (9.0% vs 17.9%).

CONCLUSIONS The Prestige LP Cervical Disc, implanted at two adjacent levels, maintains improved clinical outcomes and segmental motion 10 years after surgery and is a safe and effective alternative to fusion.

Clinical trial registration no.: NCT00637156 (clinicaltrials.gov)

Long-term clinical and radiographic outcomes of the Prestige LP artificial cervical disc replacement at 2 levels

J Neurosurg Spine 27:7–19, 2017

The aim of this study was to assess long-term clinical safety and effectiveness in patients undergoing anterior cervical surgery using the Prestige LP artificial disc replacement (ADR) prosthesis to treat degenerative cervical spine disease at 2 adjacent levels compared with anterior cervical discectomy and fusion (ACDF).

METHODS A prospective, randomized, controlled, multicenter FDA-approved clinical trial was conducted at 30 US centers, comparing the low-profile titanium ceramic composite-based Prestige LP ADR (n = 209) at 2 levels with ACDF (n = 188). Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at regular postoperative intervals to 84 months. The primary end point was overall success, a composite variable that included key safety and efficacy considerations.

RESULTS At 84 months, the Prestige LP ADR demonstrated statistical superiority over fusion for overall success (observed rate 78.6% vs 62.7%; posterior probability of superiority [PPS] = 99.8%), Neck Disability Index success (87.0% vs 75.6%; PPS = 99.3%), and neurological success (91.6% vs 82.1%; PPS = 99.0%). All other study effectiveness measures were at least noninferior for ADR compared with ACDF. There was no statistically significant difference in the overall rate of implant-related or implant/surgical procedure–related adverse events up to 84 months (26.6% and 27.7%, respectively). However, the Prestige LP group had fewer serious (Grade 3 or 4) implant- or implant/surgical procedure–related adverse events (3.2% vs 7.2%, log hazard ratio [LHR] and 95% Bayesian credible interval [95% BCI] -1.19 [-2.29 to -0.15]). Patients in the Prestige LP group also underwent statistically significantly fewer second surgical procedures at the index levels (4.2%) than the fusion group (14.7%) (LHR -1.29 [95% BCI -2.12 to -0.46]). Angular range of motion at superior- and inferior-treated levels on average was maintained in the Prestige LP ADR group to 84 months.

CONCLUSIONS The low-profile artificial cervical disc in this study, Prestige LP, implanted at 2 adjacent levels, maintains improved clinical outcomes and segmental motion 84 months after surgery and is a safe and effective alternative to fusion.

Arthroplasty Versus Fusion in Single-Level Cervical Degenerative Disc Disease

Fusion

Spine 2013;38:E1096–E1107

Study Design. A systematic review of randomized controlled trials (RCTs).

Objective. To assess the effects of arthroplasty versus fusion in the treatment of radiculopathy or myelopathy, or both, due to singlelevel cervical degenerative disc disease.

Summary of Background Data. There is ongoing debate about whether fusion or arthroplasty is superior in the treatment of single-level cervical degenerative disc disease. Mainly because the intended advantage of arthroplasty compared with fusion, prevention of symptoms due to adjacent segment degeneration in the long term, is not confirmed yet. Until sufficient long-term results become available, it is important to know whether results of 1 of the 2 treatments are superior to the other in the first 1 to 2 years.

Methods. We searched electronic databases for randomized controlled trials. We included randomized controlled trials that directly compared any type of cervical fusion with any type of cervical arthroplasty, with at least 1 year of follow-up. Study selection was performed independently by 3 review authors, and “risk of bias” assessment and data extraction were independently performed by 2 review authors. In case of missing data, we contacted the study authors or the study sponsor. We assessed the quality of evidence.

Results. Nine studies (2400 participants) were included in this review; 5 of these studies had a low risk of bias. Results for the arthroplasty group were better than the fusion group for all primary comparisons, often statistically significant. For none of the primary outcomes was a clinically relevant difference in effect size shown. Quality of the evidence was low to moderate.

Conclusion. There is low to moderate quality evidence that results are consistently in favor of arthroplasty, often statistically significant. However, differences in effect size were invariably small and not clinically relevant for all primary outcomes.

Level of Evidence: 1