Single-level Bryan cervical disc arthroplasty: evaluation of radiological and clinical outcomes after 18 years of follow-up

Comparable long-term outcomes in patients undergoing total disc replacement or anterior cervical discectomy and noninstrumented fusion

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) is the leading surgical treatment for cervical radiculopathy. However, ACDF surgery has been suggested for to accelerate the degeneration of the adjacent cervical discs, which causes so-called adjacent segment disease (ASD). Over the past 2 decades, total disc replacement (TDR)/cervical disc arthroplasty (CDA) has become an increasingly common method for treating degenerative cervical diseases. The rationale is that a synthetic disc prosthesis may preserve motion at the operated level, which is expected to lead to reduced stress on the other cervical levels and thus decrease the risk of developing ASD. However, since the method was first introduced in the early 2000s, the long-term outcome after it is still not completely understood.

PURPOSE

Our goal was to compare the long-term outcomes of TDR and ACDF procedures.

STUDY DESIGN

Retrospective case-control study.

PATIENT SAMPLE

All patients who underwent TDR due to degenerative cervical disease at Helsinki University Hospital between 2006 and 2012 (38 patients) and matched control patients who underwent ACDF during this period (76 patients) for degenerative disc disease.

OUTCOME MEASURES

The primary outcome measure was the rate of reoperations and further cervical surgeries. Secondary outcome measures included neck symptoms (Neck Disability Index, or NDI), health-related quality of life (EQ-5D-3L), satisfaction with the surgery, radiological outcomes, and employment status.

METHODS

The medical records of all patients who underwent TDR due to degenerative cervical disease at Helsinki University Hospital between 2006 and 2012 and those of the matched control patients were analyzed retrospectively. Questionnaires were sent to all available patients at the end of the follow-up (median 14 years) to evaluate their employment status, levels of satisfaction with the surgery, current neck symptoms, and health-related quality of life. Radiological outcomes were evaluated from the cervical plain radiographs, which were taken either at the end of the follow-up as a part of the present study or earlier on for other clinical reasons, but at least 2 years after index surgery.

RESULTS

The total rate of reoperations and further cervical surgeries during the follow-up of a median of 14 years was 7/38 (18%) in the TDR group and 6/76 (8%) in the ACDF group (p=.096, ns.). Total disc replacement patients were reoperated earlier, and the 5-year reoperation rate was significantly higher in the TDR group (11% vs 1.3%, p=.026). None of the TDR patients underwent further cervical surgery more than 6 years after index surgery, whereas 5/6 (83%) of the reoperated ACDF patients were reoperated after that time. There were no significant differences in the NDIs between the patient groups. The employment rate and health-related quality of life were slightly higher in the TDR group, but the differences were statistically nonsignificant. TDR was significantly better at maintaining the angular range of motion at the operated level, and the fusion rate was significantly lower among this group.

CONCLUSIONS

There were no significant differences in the long-term outcomes of ACDF and TDR when measured by reoperation rates, employment status, NDI, EuroQoL, and satisfaction with surgery. Reoperation rate and, on the other hand, employment rate and health-related quality of life, were higher in the TDR group, but the differences were statistically nonsignificant. However, TDR patients were reoperated earlier, and the 5-year reoperation rate was significantly higher in the TDR group. Randomized long-term studies in which these methods are compared are needed to further clarify the differences between them.

Cervical disc arthroplasty with the Baguera C prosthesis: clinical and radiological results of a 10-year follow-up study

PURPOSE

We evaluated the long-term safety, mobility and complications of cervical total disc arthroplasty with the Baguera®C prosthesis over 10 years.

METHODS

We included 91 patients treated by arthroplasty for cervical degenerative disc disease. A total of 113 prostheses were implanted (50 one-level, 44 two-level and 19 hybrid constructs). They were assessed for complications, clinically, with NDI and SF-12 questionnaires and by independent radiologists for ROM, HO, disc height and adjacent level degeneration.

RESULTS

No spontaneous migration, loss of fixation, subsidence, vascular complication or dislocation were observed. The reoperation rate was 1%. About 82.7% of the patients were pain free. About 9.9% were taking occasional grade I painkillers. Motricity and sensitivity were preserved in 98.8% and 96.3%. The NDI showed an average functional disability of 17.58%, 26% lower than preoperatively. The SF-12 scores were close to normal health. The average ROM at the treated level was 7.4°. Motion was preserved in 86.6%. Lack of motion was observed in 13.4%. Grades II and III H0 were present in 53.7% and 31.7%, respectively, Grade IV was present in 13.4%. Motion was preserved in 100% of the grades 0-III. The preoperative adjacent level disc height of 4.3 mm remained stable during all the follow-ups at 4.4 mm and 4.2 mm, respectively, at 5 and 10 years.

CONCLUSIONS

After 10 years, cervical arthroplasty with the Baguera®C prosthesis presents excellent safety and functional results and low complications. Motion was preserved in 86.6%, with a 7.4° ROM. Although common, HO did not hinder motion. Adjacent disc height preservation confirms some adjacent level degeneration protection.

Incidence of Heterotopic Ossification at 10 years After Cervical Disk Replacement: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

This study aimed to assess the incidence of heterotopic ossification (HO) 10 years after cervical disk replacement (CDR).

SUMMARY OF BACKGROUND DATA

HO is a common complication after CDR and may limit the range of motion of the artificial disk. As HO usually progresses slowly, a long-term follow-up is required to better understand its incidence. In recent years, the increasing number of original articles reporting 10-year outcomes gives us the opportunity to better understand the long-term incidence of HO.

MATERIALS AND METHODS

We searched PubMed, Medline, Embase, and Cochrane Library databases to identify eligible studies. The incidence of HO was pooled, and subgroup analysis was performed. Meta-regression analyses were conducted to identify factors contributing to heterogeneity.

RESULTS

Eleven studies with at least 10 years of follow-up comprising 1140 patients who underwent CDR were included. The pooled incidence of overall HO was 70% (95% CI, 60%-81%) at 10 years postoperatively, 60% (95% CI, 44%-75%) at five or six years postoperatively, and 50% (95% CI, 27%-72%) at one or two years postoperatively. The pooled incidence of severe HO (grade 3 or 4) was 37% (95% CI, 29%-45%), and mild HO (grade 1 to 2) was 30% (95% CI, 17%-44%) at 10 years of follow-up. Pooled range of motion decreased from 8.59° before surgery to 7.40° 10 years after surgery. Subgroup analysis showed that HO incidence differed according to the prosthesis type. The earlier publication was associated with a higher pooled incidence of severe HO in the meta-regression analysis.

CONCLUSIONS

This is the first meta-analysis providing detailed information on the pooled 10-year incidence of HO after CDR. The incidence of HO seems to increase with the length of follow-up.

LEVEL OF EVIDENCE

3.

Long-Term Clinical and Radiographic Outcomes After Bryan Cervical Disk Arthroplasty: A Systematic Literature Review

Introductionː Cervical disk arthroplasty is a potential alternative procedure to anterior cervical decompression and fusion for the treatment of cervical disk disease. The aim of the study was to perform a systematic literature review on long-term clinical and radiological outcomes after Bryan cervical disk arthroplasty.Material and Methodsː A systematic literature review was performed according to PRISMA guidelines via PubMed and Embase, Scopus, and the Cochrane Library database by using the following keywords: "Bryan prosthesis"; "cervical disk arthroplasty"; "outcomes"; and "long-term follow-up." Eight articles with at least 10 years of follow-up were considered for eligibility.Resultsː In total, 481 patients were enrolled in the studies. Because of the occurrence of multiple treated levels, 588 arthroplasties were performed, divided as follows: 12 C3/4 cervical disk arthroplasties (2.01%), 63 C4/5 (10.71%), 325 C5/6 (55.27%), and 188 C6/7 (31.97%). The mean preoperative cervical lordosis was 13.6 ± 9.3°, whereas the last follow-up value was 12.8 ± 8.7°. In the last follow-up, the mean segmental range of motion was 8.2 ± 3.3°.Discussion: Recent studies have suggested that cervical disk arthroplasty should be safely performed in healthy young patients with disk degeneration who may need future revision surgery. The results suggest that this procedure preserves native cervical spinal biomechanics at long-term follow-up with acceptable adjacent segments disease and periprosthetic ossifications.Conclusionsː Cervical disk arthroplasty has good long-term device survival, motility, adjacent segment degeneration, and clinical outcomes. Therefore, it represents a valid alternative for the treatment of cervical spine degenerative pathologies, especially in young patients.

Long-term follow-up MRI shows no hastening of adjacent segment degeneration following cervical disc arthroplasty

Cervical disc arthroplasty is an established procedure, but studies with data on long-term clinical outcome, reoperation for symptomatic adjacent segment degeneration (sASD), and degenerative changes based on MRI findings are rare. Thus, a file review was performed and patients with complete documentation of neurological status at preoperative, postoperative, 12 month, 3–4 years follow-up including surgical reports for reoperation with a minimum follow-up of 9 years were included. Final follow-up assessment included a physical examination, assessment of pain levels, Odoms criteria, Neck disability index. The degeneration of each cervical segment at preoperative and at final follow-up was assessed using an MRI. Forty-six out of 68 included patients participated, the mean follow-up was 11 (range 9–15) years, at which 71.7% of patients were free of arm pain, 52.2% of patients were free of neck pain, 63% of patients had no sensory dysfunction, and full motor strength was noted in 95.6% of patients. The clinical success rate was 76.1%, the mean NDI was 12%. Overall repeated procedure rate was 17%, the reoperation rate for sASD was 9%, and removal of CDA was performed in 4%. MRI showed progressive degeneration but no significant changes of SDI from preoperative to final follow-up.

Mid-long-term follow-up of operated level kinematics after single-level artificial cervical disc replacement with Bryan disc

OBJECTIVE

Evaluation of the mid-long-term kinematics of single-level Bryan artificial cervical disc replacement (ACDR) in vivo by analyzing the center of rotation (COR) at the operated level.

METHODS

A retrospective analysis was conducted using data collected from 38 patients who underwent single-level Bryan ACDR from January 2010 to March 2013. Radiological parameters including range of motion (ROM), lordosis angle, translation, and COR were obtained. Clinical outcomes were assessed based on Odom Criteria, modified Japanese Orthopedic Association (mJOA), Neck Disability Index (NDI), and Visual Analogue Scale (VAS) scores. Correlations between COR and other follow-up data were discussed at the last follow-up.

RESULTS

Compared with preoperative values, the last follow-up data showed that 86.84% of cases achieved good-or-excellent outcomes based on Odom criteria; Significant improvements were observed across all scales assessed for clinical outcomes (P < 0.05); Lordosis angle was significantly increased in both the overall cervical spine and the operated level (P < 0.05); ROM of the overall cervical spine, operated level, and adjacent levels was preserved (P > 0.05); There was no significant change in COR at the operated level (P > 0.05). At the last follow-up and at the operated level, COR (Y) showed negative correlations with ROM and translation (P < 0.05), but no follow-up data correlated with COR (X) were found (P > 0.05).

CONCLUSIONS

Satisfactory clinical and radiological outcomes were achieved 7 years or more after single-level Bryan ACDR. At the operated level, preoperative COR was maintained, probably due to replicating the physiological interrelations of COR (Y), translation, and ROM.

Effects of endplate coverage and intervertebral height change on heterotopic ossification following cervical disc replacement

Background

Heterotopic ossification (HO) is a common complication after cervical disc replacement (CDR). Biomechanical factors including endplate coverage and intervertebral disc height change may be related to HO formation. However, there is a dearth of quantitative analysis for endplate coverage, intervertebral height change and their combined effects on HO.

Methods

Patients who underwent single-level or two-level CDR with Prestige-LP were retrospectively reviewed. Clinical outcomes were evaluated through Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI) score, and visual analogue scale (VAS) score. Radiological data, including the prosthesis-endplate depth ratio, intervertebral height change, posterior heterotopic ossification (PHO) and angular parameters, were collected. Logistic regression analysis was used to identify the potential risk factors. Receiver operating characteristic curves were plotted and the cut-off values of each potential factors were calculated.

Results

A total of 138 patients with 174 surgical segments were evaluated. Both the prosthesis-endplate depth ratio (P < 0.001) and post-operative disc height change (P < 0.001) were predictive factors for PHO formation. The area under the curve (AUC) of the prosthesis-endplate depth ratio, disc height change and their combined effects represented by the combined parameter (CP) were 0.728, 0.712 and 0.793, respectively. The risk of PHO significantly increased when the prosthesis-endplate depth ratio < 93.77% (P < 0.001, OR = 6.909, 95% CI 3.521–13.557), the intervertebral height change ≥ 1.8 mm (P < 0.001, OR = 5.303, 95% CI 2.592–10.849), or the CP representing the combined effect < 84.88 (P < 0.001, OR = 10.879, 95% CI 5.142–23.019).

Conclusions

Inadequate endplate coverage and excessive change of intervertebral height are both potential risk factors for the PHO after CDR. Endplate coverage less than 93.8% or intervertebral height change more than 1.8 mm would increase the risk of PHO. The combination of these two factors may exacerbate the non-uniform distribution of stress in the bone-implant interface and promote HO development.

Computed tomography-occult discoligamentous instability following blunt cervical spine trauma

Plain CT is routinely ordered following blunt trauma of the cervical spine, and performs well in the exclusion of significant bony injuries. MRI is reserved for cases of suspected neural or posterior ligamentous compromise, and when other imaging modalities are contraindicated. There are patients however, with unremarkable radiology, and without suggestive clinical features, who are later found to have significant discoligamentous instability. In this report, we present two such cases. In both instances, worsening neurological symptoms prompted follow-up imaging, that demonstrated interval development of sub-axial cervical spondylolisthesis, requiring surgery and instrumentation. We identify and discuss radiological features that may be associated with occult discoligamentous injury, and highlight them as avenues for future research. These may prove useful in stratifying at-risk patients for further imaging in the acute setting.

Heterotopic Ossification After Prestige-LP Cervical Disc Arthroplasty Is Related to Insufficient Sagittal Coverage of the Endplate By the Prosthesis

Background

Heterotopic ossification (HO) is a major complication after cervical disc arthroplasty (CDR) that has attracted the attention of spine surgeons. There remains a great deal of controversy regarding the surgical risk factors. The present study investigated the correlation between insufficient sagittal coverage of the prosthesis-endplate and HO after CDR and explored strategies to prevent it.

Material/Methods

We included 73 patients who underwent Prestige-LP arthroplasty. Patients were divided into HO and non-HO groups. Related data, including radiological, clinical information, were collected. HO was graded using the McAfee classification. Analysis was performed to correlate HO to the surgical segmental range of motion (ROM) at last follow-up. To evaluate the insufficient sagittal coverage of the prosthesis-endplate and other factors for developing HO, receiver operating characteristic (ROC) curves were analyzed for insufficient sagittal coverage.

Results

Among 73 patients, 24 patients had HO at the last follow-up (HO incidence: 32.9%). The ROM in the HO group was significantly lower (P<0.001). The insufficient sagittal coverage of the upper and lower prosthesis-endplate, the height of intervertebral space, and the preoperative and postoperative ROM were related to HO (P<0.05). Multivariate logistic regression analysis showed that only insufficient sagittal coverage of the upper prosthesis-endplate was related to HO (P=0.023), and ROC curve analysis revealed that HO was more likely to occur with insufficient sagittal coverage distance ≥2.5 mm.

Conclusions

HO after CDR causes a reduction in ROM, the occurrence of which is associated with insufficient sagittal coverage of the prosthesis-endplate. HO was more likely to occur with insufficient sagittal coverage distance ≥2.5 mm.