Clinical and radiological outcomes following hybrid surgery in the treatment of multi-level cervical spondylosis: over a 2-year follow-up

The Evidence for the Use of Osteobiologics in Hybrid Constructs (Anterior Cervical Discectomy and Fusion and Total Disc Replacement) in Multilevel Cervical Degenerative Disc Disease: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

Examine the clinical evidence for the use of osteobiologics in hybrid surgery (combined anterior cervical discectomy and fusion (ACDF) and total disc replacement (TDR)) in patients with multilevel cervical degenerative disc disease (DDD).

METHODS

PubMed and Embase were searched between January 2000 and August 2020. Clinical studies investigating 18-80 year old patients with multilevel cervical DDD who underwent hybrid surgery with or without the use of osteobiologics were considered eligible. Two reviewers independently screened and assessed the identified articles. The methodological index for non-randomized studies (MINORS) tool and the risk of bias (RoB 2.0) assessment tool were used to assess risk of bias. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to evaluate quality of evidence across studies per outcome.

RESULTS

Eleven studies were included. A decrease in cervical range of motion was observed in most studies for both the hybrid surgery and the control groups consisting of stand-alone ACDF or TDR. Fusion rates of 70-100% were reported in both the hybrid surgery and control groups consisting of stand-alone ACDF. The hybrid surgery group performed better or comparable to the control group in terms of adjacent segment degeneration. Studies reported an improvement in visual analogue scale for pain and neck disability index values after surgery compared to preoperative scores for both treatment groups. The included studies had moderate methodological quality.

CONCLUSIONS

There is insufficient evidence for assessing the use of osteobiologics in multilevel hybrid surgery and additional high quality and controlled research is deemed essential.

Comparison of the effects of different artificial discs on hybrid surgery: A finite element analysis

In recent years, artificial cervical discs have been used in intervertebral disc replacement surgery and hybrid surgery (HS). The advantages and disadvantages of different artificial cervical discs in artificial cervical disc replacement surgery have been compared. However, few scholars have studied the biomechanical effects of various artificial disc prostheses on the human cervical spine in HS which include the Anterior Cervical Discectomy and Fusion (ACDF) and Cervical Disc Arthroplasty (CDA). This study compared the biomechanical behavior of Mobi-C and Prestige LP in the operative and adjacent segments during two-level hybrid surgery. A three-dimensional finite element model of C2-C7 was first established and validated. Subsequently, clinical surgery was then simulated to establish a surgical model of anterior cervical fusion at the C4-C5 level. Mobi-C and Prestige-LP artificial disc prostheses were implanted at the C5-C6 level to create two hybrid models. All finite element models were fixed on the lower endplate of the C7 vertebra and subjected to a load of 73.6 N and different directions of 1 Nm torque on the odontoid process of the C2 vertebra to simulate human flexion, extension, lateral bending, and axial rotation. This paper compares the ROM, intervertebral pressure, and facet joint force after hybrid surgery with the intact model. The results show that compared with Prestige LP, Mobi-C can improve ROM of the replacement segment and compensate for the intervertebral pressure of the adjacent segment more effectively, but the facet joint pressure of the replacement segment may be higher.

Current Evidence for Hybrid Constructs: Simultaneous ACDF/Arthroplasty and Arthroplasty Adjacent to Previous ACDF

It is not surprising that the utilization of hybrid constructs, combining cervical disc arthroplasty with anterior cervical disc arthroplasty, has steadily increased over the last decade. Known limitations exist with multi-level anterior cervical disc arthroplasty and cervical disc arthroplasty procedures. Hybrid surgery offers the possibility to address patient-specific pathology in a more tailored manner by restoring functional mobility and promoting fusion where appropriate. This review discusses the current evidence, both biomechanical and clinical, of hybrid surgery for 2-level and 3-level cervical disease.

Cervical disc arthroplasty combined with two-level ACDF for the treatment of contiguous three-level cervical degenerative disc disease: A comparative study

To compare the differences among constructs with one-level cervical disc arthroplasty (CDA) and two-level anterior cervical discectomy and fusion (ACDF). A retrospective study was conducted involving patients who underwent one-level CDA and two-level ACDF between June 2012 and July 2020. According to the different locations of CDA and ACDF, we divided the constructs into three types: type Ⅰa: CDA-ACDF-ACDF; type Ⅰb: ACDF-CDA-ACDF; type Ⅰc: ACDF-ACDF-CDA. The differences of clinical and radiological outcomes were evaluated. Fifty-three patients were included with 29 in type Ⅰa group, 11 in type Ⅰb group, and 13 in type Ⅰc group. After surgery, all groups showed significant improvement in apanese Orthopedic Association, Neck Disability Index, and Visual Analog Scale scores (p < 0.001). Range of motion (ROM) of the total cervical spine in type Ⅰc group decreased significantly compared with those in type Ⅰa and type Ⅰb groups (p < 0.05). No significant differences in ROM of the arthroplasty segment and the variations in ROM of the superior adjacent segment were observed among the three groups. The fusion rates of the superior ACDF segments were significantly higher at 6 and 12 months postoperatively than those of the inferior ACDF segments (p < 0.05). The clinical outcomes were similar among constructs concerning different locations of CDA and ACDF in three-level hybrid surgery. ROM of the cervical spine in type Ⅰc group decreased significantly compared with that in type Ⅰa and type Ⅰb groups. The fusion rates of superior ACDF segments were higher at early time points after surgery than those of inferior ACDF segments.

Clinical Outcomes of Cervical Hybrid Reconstructions: A Prospective Study

BACKGROUND

The study design was a prospective clinical cohort study. The aim of this study was to assess the patient-reported outcome measures (PROMs), patient satisfaction, as well as complication and reoperation rate of cervical hybrid procedures for symptomatic cervical multilevel degenerative disc disease (MLDDD). Cervical total disc replacement (CTDR) has been shown to be safe and effective for the treatment of degenerative pathologies. However, there is minimal PROMs data on the outcomes of combined CTDR and anterior cervical decompression and fusion procedures, commonly referred to as cervical hybrid surgery.

METHODS

Prospectively collected PROMs were analyzed from patients receiving cervical hybrid surgery for symptomatic cervical MLDDD. Between 2004 and 2016, data were collected preoperatively and postoperatively at 3, 6, and 12 months, then yearly thereafter. Patient reported outcome measures included patient satisfaction, visual analog score for neck and arm, and Neck Disability Index. Complication and reoperation rates were also assessed.

RESULTS

A total of 151 patients (80 males, 71 females) who had a minimum of 12 months follow up were included. The mean age was 53 years (range = 24-81), and median follow up was 2 years (range = 1-10). The median number of levels treated was 3, with 29.8%, 49.0%, and 21.2% of patients having 2, 3, and 4 levels treated, respectively. The most common indication for surgery was multilevel cervical spondylotic radiculopathy (52.8%), followed by combined cervical spondylotic radiculomyelopathy (16.7%), axial neck pain (16%), and cervical spondylotic myelopathy (13.9%). Improvement in pain and disability scores were both clinically and statistically significant (P < .001), and these improvements were sustained throughout the course of follow up. There was a 16% incidence of minor adverse events, and 3 (1.9%) reoperations.

CONCLUSIONS

Cervical hybrid surgery for cervical MLDDD demonstrates favorable and sustained clinical outcomes at short-term to midterm follow up.

LEVEL OF EVIDENCE

4.

CLINICAL RELEVANCE

Statistically and substantial clinical benefits can be achieved by cervical hybrid surgery, in the treatment of cervical pathologies including radiculopathy and myelopathy. The key principles is to follow strict indications, and to match technology with the pathology.

Cervical Spine Balance of Multilevel Total Disc Replacement, Hybrid Surgery, and Anterior Cervical Discectomy and Fusion With A Long-term Follow-up

STUDY DESIGN

Comparative study.

OBJECTIVE

The aim of this study was to compare cervical alignment among three-level total disc replacement (TDR), two prosthesis with one cage (2D1C), one prosthesis with two cages (1D2C), and anterior cervical discectomy and fusion (ACDF), then identify the importance of cervical balance of cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

There were few long-term comparisons on cervical alignment and cervical balance among three-level TDR, 2D1C, 1D2C, and ACDF for CSM.

METHODS

Twenty-eight patients with TDR, 15 with 2D1C, 36 with 1D2C, and 32 cases with ACDF were included with a mean follow-up of 90.9 ± 8.9 months. C2-C7 cervical lordosis (CL), C2-C7 sagittal vertical axis (SVA), T1 slope (T1S) were measured on x-ray at preoperation, immediate postoperation, and final follow-up, as well as range of motion (ROM), upper/lower adjacent ROM (UROM/LROM), and adjacent segment degeneration (ASD); cervical balance was assessed by T1S minus CL (T1SCL; 20°). Clinical outcomes included neck disability index (NDI) and Japanese Orthopedic Association (JOA) score.

RESULTS

NDI and JOA improved (P < 0.01)at postoperation and final-visit with no difference among four groups. ROM decreased mostly in ACDF group, although with a comparable inter-group UROM/LROM and ASD. All groups gained equal CL-improvement at final-visit. SVA and T1S together with their change were of no differences among groups (P > 0.05). There was a correlation among alignment parameters and between CL and ROM. The inter-group capacity of balance maintaining and imbalance correction was comparable (P > 0.05). The change of T1SCL was not correlated to NDI and JOA (P > 0.05).

CONCLUSION

Adjacent segments were seldom affected. Cervical alignment was equivalently rebuilt among TDR, 2D1C, 1D2C, and ACDF. It was not essential to pay excessive attention to balance.

LEVEL OF EVIDENCE

3.

Hybrid decompression and reconstruction technique for cervical spondylotic myelopathy: case series and review of the literature

The primary treatment of choice for patients with cervical spondylotic myelopathy (CSM) is surgical decompression. The benefit of operative intervention has been well established but, the surgeons' decision of operative approach remains nuanced based on patient-specific variables and surgeon preference. Decompression can involve a cervical corpectomy or a discectomy. A hybrid construct is when both a cervical corpectomy and a discectomy are done in the same patient. The purpose of this study was to review the evidence on the clinical and biomechanical outcomes of hybrid decompression and reconstruction techniques in patients with multilevel CSM. A retrospective study was performed on consecutive patients who received hybrid anterior decompression and reconstruction at Rush University between 2013-2018. Preoperative clinical and radiographic variables were analyzed to characterize specific factors leading to the decision of the surgical approach. In addition, we performed a systematic review and meta-analysis to assess superiority in terms of operative time, blood loss, cervical lordosis, patient-reported outcomes (PRO), fusion rates, and complications. Hybrid surgery (HS) was utilized in cases where multilevel CSM was present in conjunction with stenosis posterior to the vertebral body or acute kyphotic deformity. Our meta-analysis highlighted comparable PRO, complications, and rate of success fusion between 3-level anterior cervical discectomy and fusion (ACDF) and hybrid technique. Furthermore, hybrid fusion led to increased postoperative cervical lordosis, higher fusion rate, lower total complication rate, lower implant failure/mesh subsidence rate, and lower blood loss than 2-level corpectomy. The cervical hybrid technique that combines cervical corpectomy and discectomy represents a balanced option with the benefits of two commonly utilized cervical spine procedures in patients with multilevel CSM. The literature on hybrid technique suggests in cases where multilevel ACDF is not feasible, combining discectomy and corpectomy is superior to two-level corpectomy with lower complication rates, improved clinical outcome, spinal alignment correction, and stronger biomechanical properties.

Exploration on sagittal alignment and clinical outcomes after consecutive three-level hybrid surgery and anterior cervical discectomy and fusion: a minimum of a 5-year follow-up

Purpose

To compare sagittal alignment and clinical outcomes between three-level hybrid surgery (HS) and anterior cervical discectomy and fusion (ACDF) on cervical spondylotic myelopathy (CSM) over a 5-year follow-up.

Method

The study included 32 patients with ACDF, 36 patients with 1 prosthesis and 2 cages (HS1 group), and 25 cases with 2 prostheses and 1 cage (HS2 group). Alignment parameters included C2–C7 cervical lordosis (CL), C2–C7 sagittal vertical axis (SVA), T1 slope (T1S), and T1S minus CL (T1SCL). Radiographic parameters were range of motion (ROM), upper and lower adjacent ROM (UROM and LROM), and operated-segment lordosis (OPCL), as well as adjacent segment degeneration (ASD). Clinical outcomes included the neck disability index (NDI) and Japanese Orthopedic Association (JOA) score.

Results

Three groups were well-matched in demographics. All groups gained comparable improvement on NDI and JOA (P < 0.01). All groups gained CL improvement at the final visit (P < 0.05). There were no statistical differences on SVA and T1SCL among the groups and among preoperation, 1 week later, and final follow-up (P > 0.05) while T1S improved at 1 week later and final follow-up with HS2. The final change of all alignment parameters among the three groups was of no differences. ROM decreased and OPCL increased in all groups at the final follow-up (P < 0.05). UROM and LROM increased with ACDF but kept stable with HS1 and HS2. There was no inter-group difference on the incidence of ASD (P > 0.05).

Conclusion

Cervical alignment was comparably improved. HS and ACDF provided identified mid-term efficacy, and it was not necessary to have to use prosthesis on three-level CSM.

Biomechanical comparison of noncontiguous cervical disc arthroplasty and noncontiguous cervical discectomy and fusion in the treatment of noncontinuous cervical degenerative disc disease: a finite element analysis

Background

Biomechanical characteristics of noncontinuous ACDF and noncontinuous CDA in the treatment of noncontinuous cervical degenerative disc disease were still unclear. The aim of this research is to compare the differences between these two kinds of treatment methods and to verify the effectiveness of Prodisc-C in noncontinuous CDA.

Methods

Eight FEMs of the cervical spine (C2–C7) were built based on CT images of 8 mild CDDD volunteers. In the arthroplasty group, we inserted Prodisc-C at C3/4 and C5/6. In the fusion group, CoRoent® Contour and NuVasive® Helix ACP were implanted at C3/4 and C5/6. Initial loads of 75 N were used to simulate the head weight and muscle forces. The application of 1.0 N m moment on the top on the C2 vertebra was used to create motion in all directions. Statistical analyses were performed using STATA version 14.0 (Stata Corp LP, College Station, Texas, USA). Statistical significance was set at P < 0.05.

Results

The IDPs in C2/3 (P < 0.001, P = 0.005, P < 0.001, P < 0.001), C4/5 (P < 0.001), and C6/7 (P < 0.001) of the intact group were significantly less than that in the fusion group in flexion, extension, lateral bending, and axial rotation, respectively. In addition, the IDPs in C2/3 (P < 0.001, P = 0.001, P < 0.001, P < 0.001), C4/5 (P < 0.001), and C6/7 (P < 0.001) of the arthroplasty group were significantly less than that in the fusion group in flexion, extension, lateral bending, and axial rotation, respectively. Contact forces of facet joints in C2/3 (P = 0.010) in the arthroplasty group was significantly less than that in the intact group. Contact forces of facet joints in C2/3 (P < 0.001), C4/5 (P < 0.001), and C6/7 (P < 0.001) in the arthroplasty group was significantly less than that in the fusion group. Contact forces of facet joints in C2/3 (P < 0.001), C4/5 (P < 0.001), and C6/7 (P < 0.001) in the intact group were significantly less than that in the fusion group.

Conclusions

Noncontinuous CDA could preserve IDP and facet joint forces at the adjacent and intermediate levels to maintain the kinematics of cervical spine near preoperative values. However, noncontinuous ACDF would increase degenerative risks at adjacent and intermediate levels. In addition, the application of Prodisc-C in noncontinuous CAD may have more advantages than that of Prestige LP.

A comparison of anterior cervical discectomy and fusion combined with cervical disc arthroplasty and cervical disc arthroplasty for the treatment of skip-level cervical degenerative disc disease: A retrospective study

Anterior cervical discectomy and fusion (ACDF) has been widely performed for the treatment of multilevel cervical degenerative disc disease (CDDD). In recent decades, cervical disc arthroplasty (CDA) and hybrid surgery (HS) have been developed to overcome the shortcomings of ACDF. Controversy still remains with regard to the optimal surgical procedure for skip-level CDDD.A total of 55 patients who received surgical treatment for skip-level CDDD in our department were reviewed. The patients were divided into the HS group (n = 29) and the CDA group (n = 26). The collected data included Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), and Visual Analog Scale (VAS) scores, and cervical lordosis (CL), range of motion (ROM), and intervertebral disc height (IDH). Radiological changes at the intermediate segment (IS) were also collected. All data were collected preoperatively and at routine postoperative intervals of 1 week and 3, 6, and 12 months and at the last follow-up period.Compared with preoperative values, mean JOA, NDI, and VAS scores significantly improved after surgery in both the HS and CDA groups (P < .05). However, there were no significant differences between the groups (P > .05). The HS group had better CL recovery than the CDA group after surgery (P < .05). There was no significant difference in the ROM of C2-C7 between the 2 groups (P > .05). A significant difference in the ROM of the IS was found at the last follow-up between the 2 groups (P < .05). At the last-follow-up, 4 discs (14.29%) in the CDA group and 6 discs (19.36%) in the HS group had adjacent segment degeneration (ASD) without symptoms.Both HS and CDA might be considered safe and effective surgical strategies for the treatment of skip-level CDDD. Although the clinical outcomes were similar in the 2 groups, CDA altered the ROM of the IS to a lesser degree.

Multilevel cervical disc replacement versus multilevel anterior discectomy and fusion: A meta-analysis

BACKGROUND

Cervical disc replacement (CDR) has been developed as an alternative surgical procedure to anterior cervical discectomy and fusion (ACDF) for the treatment of single-level cervical degenerative disc disease. However, patients with multilevel cervical degenerative disc disease (MCDDD) are common in our clinic. Multilevel CDR is less established compared with multilevel ACDF. This study aims to compare the outcomes and evaluate safety and efficacy of CDR versus ACDF for the treatment of MCDDD.

METHODS

A meta-analysis was performed for articles published up until August 2016. Randomized controlled trials (RCTs) and prospective comparative studies associated with the use of CDR versus ACDF for the treatment of MCDDD were included in the current study. Two reviewers independently screened the articles and data following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement.

RESULTS

Seven studies with 702 enrolled patients suffering from MCDDD were retrieved. Patients who underwent CDR had similar operative times, blood loss, Neck Disability Index (NDI) scores, and Visual Analog Scale (VAS) scores compared to patients who underwent ACDF. Patients who underwent CDR had greater overall motion of the cervical spine and the operated levels than patients who underwent ACDF. Patients who underwent CDR also had lower rates of adjacent segment degeneration (ASD). The rate of adverse events was significantly lower in the CDR group.

CONCLUSION

CDR may be a safe and effective surgical strategy for the treatment of MCDDD. However, there is insufficient evidence to draw a strong conclusion due to relatively low-quality evidence. Future long-term, multicenter, randomized, and controlled studies are needed to validate the safety and efficacy of multilevel CDR.

Prevalence of adjacent segment disease following cervical spine surgery: A PRISMA-compliant systematic review and meta-analysis

Prevalence estimates of adjacent segment degeneration (ASD) following cervical spine surgery varied greatly in current studies. We conducted a systematic review and meta-analysis to summarize the point prevalence of ASD after cervical spine surgery.

METHODS

Comprehensive electronic searches of PubMed, Embase, Web of Knowledge, and Cochrane Library databases were conducted to identify any study published from initial state to January 2016. Those reporting the prevalence of ASD after cervical surgery were included. A random-effects model was used to estimate the prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD. Univariate meta-regression analyses were conducted to explore the potential associations between prevalence and length of follow-up. All analyses were performed using R version 3.2.3 (R Foundation for Statistical Computing).

RESULTS

A total of 83 studies were included in the meta-analysis. The prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD after cervical surgery was 28.28% (95% confidence interval [CI], 20.96-36.96), 13.34% (95% CI, 11.06-16.00), and 5.78% (95% CI, 4.99-6.69), respectively, in a general analysis. It was found 2.79%, 1.43%, and 0.24% additions per year of follow-up in the incidence of radiographic ASD, symptomatic ASD, and reoperation ASD, respectively.

CONCLUSION

This meta-analysis provides some details about the prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD after cervical spine surgery. However, the results of this meta-analysis should be interpreted with caution because of the heterogeneity among the studies.

Biomechanical Analysis of a Novel Prosthesis Based on the Physiological Curvature of Endplate for Cervical Disc Replacement

STUDY DESIGN

Biomechanical analysis of a novel prosthesis based on the physiological curvature of endplate was performed.

OBJECTIVE

To compare the biomechanical differences between a novel prosthesis based on the physiological curvature of the endplate and the Prestige LP prosthesis after cervical disc replacement (CDR).

SUMMARY OF BACKGROUND DATA

Artificial disc prostheses have been widely used to preserve the physiological function of treated and adjacent motion segments in CDR, while most of those present a flat surface instead of an arcuate surface which approximately similar to anatomic structures in vivo. We first reported a well-designed artificial disc prosthesis based on the physiological curvature of the endplate.

METHODS

Three motion segments of 24 ovine cervical spines (C2-5) were evaluated in a robotic spine system with axial compressive loads of 50N. Testing conditions were as follows: 1) intact, 2) C3-4 CDR with artificial disc prosthesis based on the physiological curvature of the endplate, and 3) C3-4 CDR with the Prestige LP prosthesis. The range of motion (ROM) and the pressures on the inferior surface of the two prostheses were recorded and analyzed.

RESULTS

As compared to the intact state, the ROM of all three segments had no significant difference in the replacement group. Additionally, there was no significant difference in ROM between the two prostheses. The mean pressure on the novel prosthesis was significantly less than the Prestige LP prosthesis.

CONCLUSION

ROM in 3 groups (intact group, CDR group with novel prosthesis and CDR group with Prestige LP) showed no significant difference. The mean pressure on the inferior surface of the novel prosthesis was significantly lower than the Prestige LP prosthesis. Therefore, the novel artificial disc prosthesis is feasible and effective, and can reduce the implant-bone interface pressure on the endplate, which may be one possible reason of prosthesis subsidence.

The Role of Posterior Longitudinal Ligament in Cervical Disc Replacement: An Ovine Cadaveric Biomechanical Analysis

Background

Cervical disc replacement (CDR) has been widely used to restore and maintain mobility and function of the treated and adjacent motion segments. Posterior longitudinal ligament (PLL) resection has been shown to be efficient in anterior cervical decompression and fusion. However, less is known about the biomechanical effect of PLL removal versus preservation in cervical disc arthroplasty.

Material/Methods

Three motion segments of 24 ovine cervical spines (C2–C5) were evaluated in a robotic spine system with axial compressive loads of 50 N. These cervical spines were divided in three groups according to the following conditions: (1) intact spine, (2) C3/C4 CDR with the Prestige LP prosthesis and PLL preservation, and (3) C3/C4 CDR with the Prestige LP prosthesis and PLL removal. The ranges of motion (ROMs) were recorded and analyzed in each group.

Results

The C3/C4 ROM in group 3 (CDR with PLL removed) increased significantly in flexion-extension and axial rotation compared with group 1 (intact spine). Moreover, in flexion-extension, the mean total ROM was significantly larger in group 3 than in group 1. All the ROM observed in group 2 (CDR with PLL preserved) did not significantly differ from the ROM observed in group 1.

Conclusions

Compared with intact spines, CDR with PLL removal partly increased ROM. Moreover, the ROM in CDR with PLL preservation did not significantly differ from the ROM observed in intact spines. The PLL appears to contribute to the balance and stability of the cervical spine and should thus be preserved in cervical disc replacement provided that the posterior longitudinal ligament is not degenerative and the compression can be removed without PLL takedown.