Treating multi-level cervical disc disease with hybrid surgery compared to anterior cervical discectomy and fusion: a systematic review and meta-analysis

Biomechanical Effects on the Prostheses and Vertebrae of Three-Level Hybrid Surgery: A Finite Element Study

PURPOSE

Three-level hybrid surgery (HS) consisting of cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) has been partly used for the treatment of multi-level cervical degenerative disc disease (CDDD). The complications related to the implants and the collapse of the surgical vertebral bodies had been reported in multi-level anterior cervical spine surgery. Thus, this study aimed to explore the biomechanical effects on the prostheses and vertebrae in three-level HS.

METHODS

A FE model of cervical spine (C0-T1) was constructed. Five surgical models were developed. They were FAF model (ACDF-CDA-ACDF), AFA model (CDA-ACDF-CDA), FFF model (three-level ACDF), SF model (single-level ACDF), and SA model (single-level CDA). A 75-N follower load and 1.0-N·m moment was applied to produce flexion, extension, lateral bending, and axial rotation.

RESULTS

Compared with the intact model, the range of motion (ROM) of total cervical spine in FAF model decreased by 34.54%, 54.48%, 31.76%, and 27.14%, respectively, in flexion, extension, lateral bending, and axial rotation, which were lower than those in FFF model and higher than those in AFA model. The ROMs of CDA segments in FAF and AFA models were similar to the intact model and SA model. Compared with the intact model, the ROMs at C3/4 segment in FFF model increased from 5.71% to 7.85%, and increased from 5.31% to 6.81% at C7/T1 segment, following by FAF model, then the FAF model. The maximum interface pressures of the Prestige-LP in FAF model were similar to SA model, however the corresponding values were increased in AFA model. The maximum interface pressures of the Zero-P were increased in FAF and AFA model compared with those in SF and FFF models. The stress was mainly distributed on the screws. In AFA model, the maximum pressures of the ball and trough articulation in superior and inferior Prestige-LP were all increased compared with those in SA and FAF model. In FFF model, the maximum pressures of the vertebrae were higher than those in other models. The stress was mainly distributed on the anterior area of the vertebral bodies.

CONCLUSIONS

HS seemed to be more suitable than ACDF for the surgical treatment of three-level CDDD in consideration of the biomechanical effects, especially for the two-level CDA and one-level ACDF construct. But a more appropriate CDA prosthesis should be explored in the future.

Biomechanical Analysis of Hybrid Artificial Discs or Zero-Profile Devices for Treating 1-Level Adjacent Segment Degeneration in ACDF Revision Surgery

OBJECTIVE

Cervical hybrid surgery optimizes the use of cervical disc arthroplasty (CDA) and zero-profile (ZOP) devices in anterior cervical discectomy and fusion (ACDF) but lacks uniform combination and biomechanical standards, especially in revision surgery (RS). This study aimed to investigate the biomechanical characteristics of adjacent segments of the different hybrid RS constructs in ACDF RS.

METHODS

An intact 3-dimensional finite element model generated a normal cervical spine (C2-T1). This model was modified to the primary C5-6 ACDF model. Three RS models were created to treat C4-5 adjacent segment degeneration through implanting cages plus plates (Cage-Cage), ZOP devices (ZOP-Cage), or Bryan discs (CDA-Cage). A 1.0-Nm moment was applied to the primary C5-6 ACDF model to generate total C2-T1 range of motions (ROMs). Subsequently, a displacement load was applied to all RS models to match the total C2-T1 ROMs of the primary ACDF model.

RESULTS

The ZOP-Cage model showed lower biomechanical responses including ROM, intradiscal pressure, maximum von Mises stress in discs, and facet joint force in adjacent segments compared to the Cage-Cage model. The CDA-Cage model exhibited the lowest biomechanical responses and ROM ratio at adjacent segments among all RS models, closely approached or lower than those in the primary ACDF model in most motion directions. Additionally, the maximum von Mises stress on the C3-4 and C6-7 discs increased in the Cage-Cage and ZOP-Cage models but decreased in the CDA-Cage model when compared to the primary ACDF model.

CONCLUSION

The CDA-Cage construct had the lowest biomechanical responses with minimal kinematic change of adjacent segments. ZOP-Cage is the next best choice, especially if CDA is not suitable. This study provides a biomechanical reference for clinical hybrid RS decision-making to reduce the risk of ASD recurrence.

Biomechanical analysis of single and multi-level artificial disc replacement (ADR) in cervical spine using multi-scale loadings: A finite element study

Artificial disc replacement (ADR) is a clinical procedure used to diagnose cervical degenerative disc disease, preserving range of motion (ROM) at the fixation level and preventing adjacent segment degeneration (ASD). This study analyzed the biomechanics of ADR by examining range of motion (ROM), stress levels in bone and implants, and strain in the bone-implant interface using multi-scale loadings. The study focused on single- and double-level patients across various loading scales during physiological motions within the cervical spine. Results showed increased ROM in single-level and double-level fixations during physiological loadings, while ROM decreased at the adjacent level of fixation with the intact cervical spine model. The Prodisc-Implant metal endplate experienced a maximum von Mises stress of 432 MPa during axial rotation, confirming the long durability and biomechanical performance of the bone-implant interface.

Assessing Surgical Outcomes for Cage Plate System versus Stand-Alone Cage in Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is a common surgical procedure for addressing cervical spine conditions. It involves the utilization of either cage plate system (CPS) or stand-alone cage (SC). The objective of our study is to compare perioperative complications, patient-reported clinical outcomes measures, and radiographic outcomes of SC versus CPS in ACDF.

METHODS

We carried out a literature search in PubMed, Embase, Cochrane library, Web of science, Medline, and Google Scholar. All studies comparing the outcomes between CPS versus SC in ACDF were included.

RESULTS

Forty-one studies, 33 observational and 8 randomized clinical trials met the inclusion criteria. We found that both devices demonstrated comparable effectiveness in monosegmental ACDF with respect to Japanese Orthopedic Association Score, Neck Disability Index score, visual analog score, and fusion rates. CPS demonstrated superior performance in maintaining disc height, cervical lordosis, and exhibited lower incidence rates of cage subsidence. SC showed significant advantages over CPS in terms of shorter surgical duration, less intraoperative bleeding, shorter duration of hospitalization, as well as lower incidence rates of early postoperative dysphagia and adjacent segment disease.

CONCLUSIONS

Most of the included studies had monosegmented fusion, and there wasn't enough data to set recommendations for the multisegmented fusions. Larger studies with longer follow-up are necessary to draw more definitive conclusions to provide evidence for clinicians to make clinical decisions.

No Difference in Two-Year Revisions Between Hybrid Fusion and Two-Level Anterior Discectomy and Fusion: A National Database Study

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

This study utilized a large national database to compare two-year revision rates, in addition to complications and costs, of hybrid surgery (HS) compared to two-level anterior cervical discectomy and fusion (ACDF).

METHODS

This study used the PearlDiver Mariner dataset selecting for patients aged 18 and older who had at least 90-day active longitudinal follow-up who underwent two-level ACDF or two-level Hybrid surgery (single level ACDF and single level CDA). Patients with prior spinal trauma, infection, cancer, or posterior fusion were excluded. Primary outcomes measures were 90-day major and minor medical complications, ED visits, readmissions, as well as two-year revisions. Patients were also assessed for postoperative dysphagia, incidental durotomy, vascular injury, 90-day surgical site, and implant complications. Additionally, hospitalization and postoperative costs were evaluated.

RESULTS

There were 4570 two-level ACDF surgeries and 888 hybrid surgeries. After matching the cohorts, no statistical differences in demographics were found. There were no differences in reoperation rates at all measured time points nor 2-year complications. HS had a lower incidence of major (1.6% vs 3.1%, P = .003) and minor complications (3.0% vs 4.6%, P = .009) than ACDF. 90-day readmission was lower in the HS cohort (2.8% vs 4.2%), P = .024. HS was associated with reduced hospitalization costs -$2614 (-$3916 to -$904, P < .001). 3516 patients had ACDF, and 699 had HS with at least 2 years of follow-up.

CONCLUSION

Hybrid surgery is a safe and effective surgical treatment for cervical disease in appropriately selected patients.

Changes in the centre of rotation and the anterior bone loss of the vertebral body in Mobi-C artificial disc replacement segments after cervical hybrid surgery: a retrospective study

OBJECTIVE

To examine the short-term efficacy and imaging results of using the Mobi-C in cervical hybrid surgery on 2-level cervical spondylolisthesis. To observe post-operative changes in the flexion-extension centre of rotation (FE-COR) and anterior bone loss (ABL) of the anterior cervical disc replacement (ACDR) segment.

METHODS

Forty-two patients (20 males and 22 females, aged 42‒67 years) who underwent cervical hybrid surgery were retrospectively analysed. Their ACDR segment used Mobi-C, and the fusion segment used ROI-C, with a follow-up of 25‒42 months (31.1 ± 4.8 months). The modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI), and visual analogue scale (VAS) were used to assess clinical outcomes. Pre-operative, 6-month post-operative, and final follow-up radiographs were collected to compare total cervical spine curvature (C2-C7), curvature of the operated segments, range of motion (ROM) in the total cervical spine, operated segmental ROM, ACDR segmental ROM, and operated adjacent segmental ROM. The height of the superior articular process (HSAP), the orientation of zygapophyseal joint spaces (OZJS), and the length of the superior articular surface (LSAS) were measured. The FE-COR of the ACDR segment was measured using the mid-plumb line method. The translation distance of the Mobi-C was measured. The degree of disc degeneration in the adjacent segment, bony fusion of the ACDF segment, and ABL of the upper and lower vertebra of the ACDR segment were observed.

RESULTS

In our group, all patients have shown improvements in their postoperative mJOA, NDI, and VAS scores. Overall cervical ROM and surgical segmental ROM decreased (P < 0.05). However, there was no significant decrease in ACDR segmental ROM and upper or lower adjacent segmental ROM compared with pre-operatively (P > 0.05). For FE-COR-X, only the last follow-up compared with pre-surgery showed statistical significance (46.74 ± 7.71% vs. 50.74 ± 6.92%, P < 0.05). For FE-COR-Y, the change was statistically significant at both 6 months post-operation and the final follow-up compared to pre-operation (45.37% ± 21.11% vs. 33.82% ± 10.87%, 45. 37% ± 21.11% vs. 27.48% ± 13.58%, P < 0.05). No significant difference in the Mobi-C translation distance was observed (P > 0.05). Moreover, the difference in HSAP was not statistically significant at each node (P > 0.05). The OZJS and LSAS were significantly different at the final follow-up compared to the pre-operative period (P < 0.05). All the ACDF segments were observed in a stable condition at the final follow-up. Furthermore, 9 of the adjacent segments showed imaging ASD (9/82, 10.98%), and all were present at the last follow-up, of which 6 were mild, and 3 were moderate. Twenty of the 42 Mobi-C segments had no significant ABL (grade 0) 6 months post-operatively (47.62%). Sixteen cases (38.10%) showed mild ABL (grade 1), and 6 cases (14.28%) showed moderate ABL (grade 2). No severe ABL occurred.

CONCLUSION

The cervical hybrid surgery using Mobi-C artificial cervical discs can achieve satisfactory results. The Mobi-C segmental FE-COR-X shows a slow forward shift trend, and FE-COR-Y drops noticeably within 6 months post-surgery before stabilizing. It's common to see mild to moderate ABL after cervical hybrid surgery using Mobi-C, and significant progression is unlikely in the short term. Furthermore, changes in the FE-COR after hybrid surgery in the Mobi-C segment might not affect clinical outcomes.

The Role of Osteobiologics in Augmenting Spine Fusion in Unplated Anterior Cervical Discectomy and Fusion Compared to Plated Constructs: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To compare clinical and radiographic outcomes as well as complications of unplated vs plated anterior cervical discectomy and fusion (ACDF) surgery considering the role of osteobiologics in single- and multi-level procedures.

METHODS

A systematic search of PubMed/MEDLINE, Scopus, CINAHL, EMBASE, CENTRAL, Cochrane and ClinicalTrials.gov databases was performed. Briefly, we sought to identify studies comparing unplated vs. plated ACDF for cervical degenerative disc disease reporting the use of osteobiologics in terms of clinical outcomes, radiographic fusion, and complications. Data on study population, follow-up time, type of cage and plate used, type of osteobiologic employed, number of levels treated, patient-reported outcomes (PROs), radiographic outcomes and complications were collected and compared. Relevant information was pooled for meta-analyses.

RESULTS

Thirty-eight studies met the inclusion criteria. No significant difference was found in terms of clinical outcomes between groups. Unplated ACDF was characterized by reduced blood loss, operation time and length of hospital stay. Fusion was achieved by the majority of patients in both groups, with no evidence of any specific contribution depending on the osteobiologics used. Dysphagia was more commonly associated with anterior plating, while cage subsidence prevailed in the unplated group.

CONCLUSION

Unplated and plated ACDF seem to provide similar outcomes irrespective of the osteobiologic used, with minor differences with doubtful clinical significance. However, the heterogeneity and high risk of bias affecting included studies markedly prevent significant conclusions.

Sagittal sequence and clinical efficacy of cervical disc replacement and hybrid surgery in the treatment of cervical spondylotic myelopathy: a retrospective study

Background

Hybrid surgery (HS) combines anterior cervical discectomy and fusion (ACDF) with cervical disc replacement (CDR) is gradually being more frequently implemented, but there are few studies reporting the safety and effectiveness of hybrid surgery in three levels cervical spondylotic myelopathy.

Methods

The clinical and radiographic data of patients with three-segment cervical spondylosis, who underwent CDR, ACDF and HS in our hospital from February 2007 to February 2013 were analyzed. The Visual Analog Scale (VAS), Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) were used to evaluate the clinical efficacy post surgery. Cervical spine x-rays were conducted to assess ROM, CL, T1S and relevant outcomes.

Results

A total of 94 patients were included in the study: 26 in the CDR group, 13 in the HS1 group, 31 in the HS2 group, and 24 in the ACDF group. Most patients in the CDR group were younger. There was no difference in the follow-up duration, blood loss volume or surgery time (P > 0.05). Four groups reported improvements in JOA and NDI scores compared to baseline. There was no significant difference in the final JOA, final NDI or recovery rate among the 4 groups. The final ROM was smaller in the ACDF group than in the other 3 groups. There was no difference among the four groups in the final UROM, final LROM or their changes. There was no difference in the final T1S, final SVA or their change among the four groups. All groups showed similar changes in CL and T1S-CL.

Conclusions

There was no difference in the clinical outcomes of ACDF, CDR, or hybrid surgery. CDR can better preserve the mobility of the cervical spine. Neither CDR nor hybrid surgery was significantly advantageous over ACDF in restoring the sagittal sequence in patients with three-level CSM.

Risk Factors for Significant Intraoperative Blood Loss during Anterior Cervical Decompression and Fusion for Degenerative Cervical Diseases

OBJECTIVES

Anterior cervical decompression and fusion (ACF) has become a widely accepted surgical treatment for degenerative cervical diseases, but occasionally, significant intraoperative blood loss (SIBL), which is defined as IBL of 500 mL or more, will occur. We aimed to investigate the independent risk factors for SIBL during ACF for degenerative cervical diseases.

METHODS

We enrolled 1150 patients who underwent ACF for degenerative cervical diseases at our hospital between 2013 and 2019. The patients were divided into two groups: the SIBL group (n = 38) and the non-SIBL group (n = 1112). Demographic, surgical and radiographic data were recorded prospectively to investigate the independent risk factors for SIBL. For counting data, the chi-square test or Fisher's exact probability test was used. Student's t-test or the Mann-Whitney rank sum test was used for comparisons between groups of measurement data. Univariate analysis and multivariate logistic regression analysis were further used to analyze the significance of potential risk factors.

RESULTS

The incidence of SIBL during ACF was 3.3% (38/1150). A multivariate analysis revealed that female sex (odds ratio [OR], 6.285; 95% confidence interval [CI], 2.707-14.595; p < 0.001), corpectomy (OR, 3.872; 95% CI, 1.616-9.275; p = 0.002), duration of operation ≥150 min (OR, 8.899; 95% CI, 4.042-19.590; p < 0.001), C3 involvement (OR, 4.116; 95% CI, 1.808-9.369; p = 0.001) and ossification of posterior longitudinal ligament (OPLL) at the surgical level (OR, 6.007; 95% CI, 2.218-16.270; p < 0.001) were independent risk factors for SIBL. Patients with SIBL had more days of first-degree/intensive nursing (p = 0.003), longer length of stay (p = 0.003) and higher hospitalization costs (p = 0.023).

CONCLUSION

Female sex, corpectomy, duration of operation, C3 involvement and OPLL at the surgical level were independent risk factors for SIBL during ACF. SIBL in ACF was associated with more days of first-degree/intensive nursing, longer length of stay and higher hospitalization costs.

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.

Anterior Fusion and Long-Term Cervical Mobility in Patients With Traumatic Spinal Cord Injury: An Observational Study

Objective This study aims to determine and quantify the impairment of cervical mobility and range of motion in patients with traumatic spinal cord injury (SCI) and subsequent cervical subaxial fusion surgery. Methods A total of 89 patients who underwent interbody fusion of the cervical spine and were admitted to the Spinal Cord Injury Center of the BG Klinikum Hamburg, Germany between 2003 and 2018 were examined after their in-facility rehabilitation was successfully completed. Reclination, inclination, tilt, and rotation of the cervical spine were examined and documented in addition to overall patient characteristics and fusion extent. Results We could identify fusion length and age to be independently negatively correlated with the cervical range of motion in different degrees of movement. We could also show a significant decrease in cervical mobility within our patients when compared to healthy adults. The ability to tilt and rotate the cervical spine was particularly impaired. Conclusions Patients with traumatic SCI and intervertebral fusion suffer from significant impairment of mobility in different degrees of movement. This knowledge can be used to evaluate the rehabilitative challenges and reintegrative needs of individuals after traumatic SCI. Rehabilitation should be adjusted accordingly.

Classification of three-level hybrid surgery for the treatment of cervical degenerative disc disease: a retrospective study of 108 patients

INTRODUCTION

According to the different numbers and locations of cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF), three-level hybrid surgery (HS) has many constructs. The purpose of the present study was to introduce a classification system for three-level HS and compare the two types with each other and with ACDF.

METHODS

A retrospective study was conducted involving patients with three-level cervical degenerative disc disease (CDDD) who underwent ACDF or HS in our hospital between June 2012 and May 2019. According to the different numbers and locations of ACDFs and CDAs, we classified the three-level HS into two types (type I: one-level CDA and two-level ACDF, and type II: two-level CDA and one-level ACDF). The differences of clinical and radiological outcomes were compared with each other and with three-level ACDF.

RESULTS

A total of 108 patients were analyzed. The Neck Disability Index (NDI) of the ACDF group at 3 months postoperatively was significantly higher than that in the type I and type II groups (p < 0.05). The cervical lordosis was significantly lower in the ACDF group than that in the type I and II groups at 3 days, 6, 12 months postoperatively and the final follow-up (p < 0.05). The range of motion (ROM) of the total cervical spine decreased significantly in all three groups at 3, 6, and 12 months postoperatively and at the final follow-up (p < 0.05). The ACDF group was observed with the most severe loss of ROM of the total cervical spine, followed by the type I group. The type II group could preserve the most ROM of the total cervical spine. The ROM of adjacent segments increased most in the ACDF group, followed by the type I group.

CONCLUSIONS

Compared with ACDF, three-level HS may yield a faster recovery rate and superior radiological outcomes, such as a superiority in maintaining the cervical curvature and ROM of the total cervical spine and a smaller increase in the ROM of adjacent segments. The advantages were most remarkable in the type II group.

Comparison of Radiographic Reconstruction and Clinical Improvement between Artificial Cervical Disc Replacement and Anterior Cervical Discectomy and Fusion

Background

The surgical management of cervical degenerative disc degeneration (CDDD) has not reached a consensus. Artificial cervical disc replacement (ACDR) has been shown to be efficient in reducing symptoms after CDDD, although the topic remains highly controversial in this field. This study aimed to evaluate the effectiveness of ACDR on the treatment of CDDD on the aspect of radiographic reconstruction and clinical improvement compared with anterior cervical discectomy and fusion (ACDF).

Methods

This was a retrospective comparative study with 47 patients who underwent single-level ACDR and 46 patients who underwent single-level ACDF. The radiographic reconstruction was assessed by the cervical sagittal alignment parameters, consisting of two aspects, distance and angle, such as cervical sagittal vertical axis (cSVA), cervical lordosis (CL), T1 slope (T1s), and intervertebral space height (ISH). The clinical improvement was assessed by patient-related outcomes (PROs), consisting of two aspects, relief of axial neck pain and recovery of cervical dysfunction, measured through the Visual Analogue Scale (VAS), Neck Disability Index (NDI), and Japanese Orthopedic Association (JOA).

Results

Significant variations were achieved on aspects of radiographic reconstruction and clinical improvement after ACDR (P < 0.05), which were similar to that of the ACDF group (P < 0.05). A significantly larger postoperative range of motion (ROM) was found in patients less than 45 years of age in the ACDR group (P < 0.05). In addition, a significantly better postoperative JOA was found in patients with a preoperative ISH less than 4 mm in the ACDF group than that in the ACDR group (P < 0.05). Other than that mentioned above, no significant variations in radiographic and clinical outcomes were found between the two groups (P > 0.05).

Conclusions

Overall, this study showed that a similar capability in terms of radiographic reconstruction and clinical improvement was found between the two methods. Specific concerns should be analyzed while choosing between an ACDR and an ACDF. It should be pointed out that, based on our experience, if the patient is younger, ACDR is recommended; for patients with preoperative ISH less than 4 mm, ACDF is more recommended.

Hybrid Anterior Cervical Discectomy and Fusion and Cervical Disc Arthroplasty: An Analysis of Short-Term Complications, Reoperations, and Readmissions

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Although cervical disc arthroplasty (CDA) has become a well-established and effective treatment for symptomatic cervical degeneration, many patients with multilevel disease are not good candidates for CDA at all levels. For such patients, hybrid surgery (HS)-a combination of adjacent anterior cervical discectomy and fusion (ACDF) and CDA-may be more appropriate. Given the novelty of HS and the relative dearth of studies adequately assessing short-term perioperative complications, this current study sought to assess the short-term morbidity profile of HS, differences in operative duration, length of stay (LOS), and readmission and reoperation rates and reasons relative to a 2-level ACDF cohort.

METHODS

All patients who underwent HS and 2-level ACDF were identified between 2011 and 2018 using a large, prospectively collected registry. Baseline patient characteristics and postoperative complications were compared using bivariate and/or multivariate analysis.

RESULTS

A total of 390 patients undergoing HS were identified. Two-level procedures were the most common (74.9%). Patients undergoing HS were more likely to be younger, male, and have fewer comorbidities. There were no differences between HS and 2-level ACDF in rates of any postoperative complication, transfusion, readmissions, and operative duration. However, HS had a decreased LOS (0.5 days), relative to a 2-level ACDF. HS patients had low rates of reoperation (1.28%) with 1 case for hematoma evacuation and another for revision CDA.

CONCLUSIONS

This study represents one of the largest cohorts of patients undergoing HS reported to date. Patients undergoing HS are not at increased risk of perioperative complications relative to a 2-level ACDF and may benefit from shorter LOS.

Anterior hybrid construction of multilevel cervical disc disease and spondylotic spinal stenosis: surgical results and factors affecting adjacent segment problems

Objective

We aimed to evaluate reliability, radiological outcomes, and the impacts of anterior cervical hybrid construction on the adjacent segments for the multilevel cervical degenerative disc disease (mCDDD) and spondylotic spinal stenosis (SSS).

Methods

A retrospective analysis was performed using data extracted from the medical files of 195 patients (105 males, 90 females; mean age: 47.7 years). From 2008 to 2018, these patients underwent anterior cervical hybrid construction for symptomatic contiguous at least 2-level cervical degenerative disc diseases and cervical spondylosis. Clinical and radiological data including Neck Disability Index (NDI), visual analogue scale (VAS), local cervical degenerative disk disease in adjacent segments on magnetic resonance imaging (MRI) views, and complications were reviewed.

Results

The mean clinical and radiological follow-up was 45.2 months (range 24 to 102). Radiculopathy and/or myelopathy were the main clinical problems in all patients. The mean VAS scores of HC for arm pain were 7.4 ± 0.8 preoperatively; 2.8 ± 0.6, 1 month after surgery; 2.3 ± 0.6, 6 months after surgery; 1.8 ± 0.6, 12 month after surgery; and 1.6 ± 0.6, 24 months after surgery. The mean NDI scores (mean ± SD) of HC significantly improved after surgery (on admission, 57.2 ± 5.5%; 1 month after surgery, 27.35 ± 5.3%; 6 month after surgery, 21.43 ± 2.8%; 12 months after surgery, 21.9 ± 2.3%; 24 months after surgery, 20.6 ± 2.6%, p = 0.006). Hoarseness and dysphagia were the most common complications and osteophyte formation was the most frequent radiographic change.

Conclusion

Anterior cervical hybrid construction appears to be an acceptable option in the management of multilevel cervical degenerative disc diseases and spondylotic spinal stenosis.

A Comparison of 2 Anterior Hybrid Techniques for 3-Level Cervical Degenerative Disc Disease

Background

Novel hybrid surgical techniques that incorporate anterior cervical discectomy and fusion with total disc replacement are widely used. Based on the number of implanted discs, 3-level hybrid surgery can be classified as single fusion combined with double replacement and single replacement combined with double fusion. Few studies to date have directly compared these hybrid techniques. The present study compared the clinical and radiological outcomes of these methods and assessed their characteristics and benefits.

Material/Methods

Clinical and radiological outcomes were retrospectively evaluated in 64 consecutive patients who underwent 3-level hybrid surgery by single fusion combined with double replacement or single replacement combined with double fusion.

Results

Significant differences between the 2 groups were observed in postoperative range of motion of C2–C7. C2–C7 cervical lordosis assessed preoperatively and at final follow-up differed significantly in patients who underwent single replacement combined with double fusion. This group showed a higher incidence of heterotopic ossification than patients who underwent double replacement combined with single fusion.

Conclusions

Both types of hybrid surgery are safe and effective in treating 3-level cervical degenerative disc diseases. Single replacement combined with double fusion showed greater accuracy in correcting cervical lordosis, but was associated with a higher incidence of heterotopic ossification. In contrast, single fusion combined with double replacement was superior in maintaining cervical range of motion.

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.

A comparison study between hybrid surgery and anterior cervical discectomy and fusion for the treatment of multilevel cervical spondylosis

AIMS

Whether to perform hybrid surgery (HS) in contrast to anterior cervical discectomy and fusion (ACDF) when treating patients with multilevel cervical disc degeneration remains a controversial subject. To resolve this we have undertaken a meta-analysis comparing the outcomes from HS with ACDF in this condition.

METHODS

Seven databases were searched for studies of HS and ACDF from inception of the study to 1 September 2019. Both random-effects and fixed-effects models were used to evaluate the overall effect of the C2-C7 range of motion (ROM), ROM of superior/inferior adjacent levels, adjacent segment degeneration (ASD), heterotopic ossification (HO), complications, neck disability index (NDI) score, visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, Odom's criteria, blood loss, and operating and hospitalization time. To obtain more credible results contour-enhanced funnel plots, Egger's and Begg's tests, meta-regression, and sensitivity analyses were performed.

RESULTS

In total, 17 studies involving 861 patients were included in the analysis. HS was found to be superior to ACDF in maintaining C2-C7 ROM and ROM of superior/inferior adjacent levels, but HS did not reduce the incidence of associated level ASD. Also, HS did not cause a higher rate of HO than ACDF. The frequency of complications was similar between the two techniques. HS failed to achieve more favourable outcomes than ACDF using the NDI, VAS, JOA, and Odom's scores. HS did not show any more advantages in operating or hospitalization time but did show reduction in blood loss.

CONCLUSION

Although HS maintained cervical kinetics, it failed to reduce the incidence of ASD. This finding differs from previous reports. Moreover, patients did not show more benefits from HS with respect to symptom improvement, prevention of complications, and clinical outcomes. Cite this article: Bone Joint J 2020;102-B(8):981-996.

Making the Most of Systematic Reviews and Meta-analyses in Spine Surgery: A Primer for the Practicing Spine Surgeon

STUDY DESIGN

Review.

OBJECTIVE

To provide practicing spine surgeons a primer with key insights for reading, interpreting, and clinically integrating systematic reviews and meta-analyses.

SUMMARY OF BACKGROUND DATA

Evidence-based medicine (EBM) refers to a family of standardized techniques for critical appraisal of clinical research. Within the contemporary spine literature, EBM is most commonly encountered in the form of systematic reviews and meta-analyses. Although these analytic techniques are potentially useful when appropriately applied to well-formulated questions with adequate primary data in the literature, the rapid and somewhat indiscriminate increase in volume of systematic reviews and meta-analyses published may be associated with an overall dilution in their quality, as well as misperceptions regarding the applicability of particular EBM studies to spine surgery in general.

METHODS

The collective experience of spine specialists with vested interests in advancing EBM and its utility was summarized into a primer.

RESULTS

We emphasize components that are pertinent methodologically (search strategy, study number, meta-analysis, bias, and certainty), and pertinent clinically (outcomes) to interpreting, and clinically integrating systematic reviews and meta-analyses into spine surgery practice.

CONCLUSIONS

Armed with these insights into these five perspectives, we anticipate that practicing spine surgeons will be better equipped to interpret systematic reviews and meta-analyses in a fashion that will meaningfully impact their patient care.

LEVEL OF EVIDENCE

2.

Pearls for Interpreting Neurosurgical Systematic Reviews and Meta-Analyses: Lessons From a Collaborative Effort

Systematic reviews and meta-analyses in the neurosurgical literature have surged in popularity over the last decade. It is our concern that, without a renewed effort to critically interpret and appraise these studies as high or low quality, we run the risk of the quality and value of evidence-based medicine in neurosurgery being misinterpreted. Correspondingly, we have outlined 4 major domains to target in interpreting neurosurgical systematic reviews and meta-analyses based on the lessons learned by a collaboration of clinicians and academics summarized as 4 pearls. The domains of (1) heterogeneity, (2) modeling, (3) certainty, and (4) bias in neurosurgical systematic reviews and meta-analyses were identified as aspects in which the authors’ approaches have changed over time to improve robustness and transparency. Examples of how and why these pearls were adapted were provided in areas of cranial neuralgia, spine, pediatric, and neuro-oncology to demonstrate how neurosurgical readers and writers may improve their interpretation of these domains. The incorporation of these pearls into practice will empower neurosurgical academics to effectively interpret systematic reviews and meta-analyses, enhancing the quality of our evidence-based medicine literature while maintaining a critical focus on the needs of the individual patients in neurosurgery.

Optimization of Three-Level Cervical Hybrid Surgery to Prevent Adjacent Segment Disease: A Finite Element Study

Hybrid surgery (HS) allows surgeons to tailor fusion and arthroplasty in the treatment of multiple-level cervical disc degeneration. However, the decision making of selecting either ACDF or ADR for each level in three-level HS remains controversial and has not been fully investigated. This study was aimed to optimize three-level cervical hybrid constructs by systematically investigating their biomechanical properties and their effect on adjacent levels. A finite element model of cervical spine (C2–C7) was developed, and eight C3–C6 surgical models including six HS were constructed. The range of motion (ROM) in flexion, extension, lateral bending, and axial rotation under 2.0 Nm moments with 30 N follower load were simulated. The von Mises stress, strain energy at the adjacent intervertebral disc (IVD) and force at the adjacent facet were calculated. The ROM of the hybrid constructs and adjacent levels was close to that of the intact spine. HS with arthroplasty performed at C5-6 had better performance in terms of ROM reduction at the inferior adjacent level (C6-7). Moreover, C-D-D and 3ADR had best performance in reducing the von Mises stress and strain energy at C6-7. All HS reduced the facet burden at both C2-3 and C6-7 levels. However, the major drawback of HS revealed here is that the effect of C6-7 protection is at the cost of increased C2-3 IVD burden. In conclusion, we recommend C-D-D and 3ADR for patient with C3–C6 disc degeneration without predisposing C2-3 condition. C-C-D could be a good alternative with a lower medical cost. This analysis guides the decision making in three-level cervical HS before future cadaver studies or human clinical trials.

THE EFFECTIVENESS OF THE MOST USED TECHNIQUES IN PATIENTS WITH DEGENERATIVE CERVICAL DISEASE

ABSTRACT The objective of this study was to discuss the three main surgical techniques currently applied in the treatment of degenerative cervical discopathy and their repercussions on patient quality of life. We considered the impact of the surgical techniques applied to the quality of life of 24 patients who underwent surgery during the period from 2010 to 2017 using the Oswestry and SF-36 scales. With the application of the questionnaires we observed, through the applicability and analysis of the quality of life results indicated in the questionnaires, that pain improvement and a reduction in work and daily activity disability were more effective with cervical arthroplasty. We concluded that with the individualization of surgical treatment, that is, through the choice of the surgical technique most appropriate for the clinical condition, the postoperative recovery and consequently the quality of life of the patient are enhanced. Level of evidence IV; Descriptive study.

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.

Comparison of 2-year follow-up results of the hybrid surgery using Mobi-C combined with ROI-C and anterior cervical discectomy and fusion for the treatment of contiguous two-level cervical degenerative disc diseases

Although the Mobi-C artificial disc and the ROI-C cervical cage have been widely used in the treatment of cervical degenerative disc diseases (CDDD), few reports addressed the features of combined application of both devices. This study is aimed at comparing the clinical and radiological outcomes of treating contiguous two-level CDDD using Mobi-C and ROI-C combined in a hybrid surgery (HS) with anterior cervical discectomy and fusion (ACDF) using ROI-C. We reviewed ninety-one patients who underwent HS (n = 48) or ACDF (n = 43) surgery for symptomatic contiguous two-level CDDD. >2 years' clinical and radiological outcomes were reviewed and evaluated retrospectively. At the last follow-up, significant improvement in the mean VAS, JOA, and NDI scores was found both in the HS and ACDF groups (p < 0.05), while the differences between groups were not significant (p > 0.05). The global range of motion (ROM) in the HS group was significantly larger than that in the ACDF group (p < 0.05). The local lordosis improved significantly after surgery in all patients (p < 0.05). Bone resorption and heterotopic ossification (HO) were found after surgery. The result showed that, for the selected patients, HS may provide an alternative approach for the treatment of contiguous two-level CDDD. HS also offers the benefit of both greater global ROM and greater ROM at the Mobi-C index level. Some degree of bone resorption may be an integral component in the early stage of bony fusion in the cage index level. Further studies and long-term follow-up are still needed.

The safety and efficacy of hybrid surgery for multilevel cervical degenerative disc disease versus anterior cervical discectomy and fusion or cervical disc arthroplasty: a systematic review and meta-analysis

BACKGROUND

Multilevel cervical degenerative disc disease (CDDD) can be treated surgically with anterior cervical discectomy and fusion (ACDF), cervical disc arthroplasty (CDA), or a hybrid surgery (HS) of the two in which both procedures are used at different vertebral levels. A systematic review and meta-analysis was performed to compare the clinical and radiographical outcomes of HS against ACDF or CDA alone.

METHODS

Three electronic databases were searched for articles published before December 2018. The literature was searched and assessed by independent reviewers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement.

RESULTS

Eight papers were identified as eligible with a total of 424 patients. Post-operative C2-C7 range of motion (ROM) was significantly greater after HS than ACDF (p = 0.004; mean difference (MD) 6.14°). The ROM of the superior adjacent segment was significantly lower after HS than ACDF (p < 0.0001; MD - 2.87°) as was the ROM of the inferior adjacent segment (p = 0.0005; MD - 3.11°). HS patients' return to work was shorter than those who underwent ACDF (p < 0.00001; MD - 32.01 days) and CDA (p < 0.00001; MD - 32.92 days). There were no statistically significant differences in functional outcomes following CDA compared with HS. There was no significant difference in operation time, intra-operative blood loss, or post-operative complications between any of the procedures.

CONCLUSION

The number of included studies was small, the heterogeneity between them was substantial, and the quality of evidence was very low. Large randomised controlled trials are required to provide strong evidence that would enable recommendation of one intervention over another.

Comparison of Anterior Cervical Discectomy and Fusion With a Stand-Alone Interbody Cage Versus a Conventional Cage-Plate Technique: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Compare the clinical and radiographic outcomes of anterior cervical discectomy and fusion (ACDF) with a stand-alone interbody cage versus a conventional cage and anterior cervical plate technique.

METHODS

A systematic Medline search was conducted using PubMed, EMBASE, and Cochrane Library Database of Systematic Reviews. Search terms included "anterior cervical discectomy and fusion," "cage," and "bone plates," or variations thereof. Only studies involving a direct comparison of ACDF with a stand-alone cage versus a cage and plate were included. From the selected studies, we extracted data on patient demographics, comorbidities, surgical risk factors, and pre- and postoperative radiographic findings. A meta-analysis was performed on all outcome measures. The quality of each study was assessed using the Downs and Black checklist.

RESULTS

Nineteen studies met the inclusion and exclusion criteria. Patients who underwent ACDF with a cage-only technique had significantly lower rates of postoperative dysphagia and adjacent segment disease compared with patients who underwent ACDF with a cage-plate technique. However, patients who underwent ACDF with a cage-plate technique had better radiographic outcomes with significantly less subsidence and better restoration of cervical lordosis. There were no other significant differences in outcomes or postoperative complications.

CONCLUSIONS

ACDF with a cage-only technique appears to have better clinical outcomes than the cage-plate technique, despite radiographic findings of increased rates of subsidence and less restoration of cervical lordosis. Future randomized controlled trials with longer term follow-up are needed to confirm the findings of this meta-analysis.

The future of disc surgery and regeneration

Low back and neck pain are among the top contributors for years lived with disability, causing patients to seek substantial non-operative and operative care. Intervertebral disc herniation is one of the most common spinal pathologies leading to low back pain. Patient comorbidities and other risk factors contribute to the onset and magnitude of disc herniation. Spine fusions have been the treatment of choice for disc herniation, due to the conflicting evidence on conservative treatments. However, re-operation and costs have been among the main challenges. Novel technologies including cage surface modifications, biologics, and 3D printing hold a great promise. Artificial disc replacement has demonstrated reduced rates of adjacent segment degeneration, need for additional surgery, and better outcomes. Non-invasive biological approaches are focused on cell-based therapies, with data primarily from preclinical settings. High-quality comparative studies are needed to evaluate the efficacy and safety of novel technologies and biological therapies.

Comparative Study Between M6-C and Mobi-C Cervical Artificial Disc Replacement: Biomechanical Outcomes and Comparison with Normative Data

OBJECTIVE

Cervical spondylosis affects a huge proportion of the middle-aged population. Degenerative changes can occur in multiple regions of the cervical spine typically affecting the joints, intervertebral discs and endplates. These changes lead to compression of adjacent nervous structures, which results in radiculopathic and myelopathic pain. Various treatment modalities are currently available with non-surgical approaches the initial go to if there is no symptomatic cord compression. Anterior cervical discectomy and fusion, or arthroplasty are the two common surgical approaches if non-surgical treatments fail to relieve symptoms of the patients or there are signs of central cord compression. However, studies have shown that there is an increased risk of adjacent segment disease related to fusion. Cervical disc arthroplasty aims to restore normal range of motion (ROM) in patients with pain and disability due to degenerative disc disease resistant to conservative care. Two common disc prostheses used include M6-C and Mobi-C. Both prostheses comprise a mobile polymer segment sandwiched between two metal endplates with mechanisms resembling an actual intervertebral disc. This study aims to compare the kinematics associated with these prostheses, against the normal range of motion in the non-degenerative population.

METHOD

Patients who underwent M6-C or Mobi-C disc replacements by the senior author from 2012 to 2015 were identified at a single tertiary institution. Routine 3-month postoperative lateral radiographs were analyzed for flexion and extension ROM angles at the involved vertebral level by two independent authors. Data was compared to previous published studies investigating cervical spine ROM of asymptomatic patients.

RESULTS

There was no statistical significance in the difference of overall flexion range between M6-C and Mobi-C prostheses. However, overall range of extension of Mobi-C was greater compared to M6-C (P = 0.028). At C_5-6 , the range of flexion for both implants were similar but lesser compared to asymptomatic patients (P < 0.001). Range of extension was greater in the Mobi-C group (14.2° ± 5.1°) compared to the M6-C (7.3° ± 4.6°) (P = 0.0009). At C_6-7 , there were no statistical differences in both range of flexion and extension between the two prostheses and asymptomatic patients (P > 0.05).

CONCLUSION

The early results regarding restoration of ROM following cervical arthroplasty using either M6-C or Mobi-C prosthesis are encouraging. Long-term follow-up studies are necessary to observe the change in ROM over time with physiological loading and wear patterns.

Comparison of 6-year Follow-up Result of Hybrid Surgery and Anterior Cervical Discectomy and Fusion for the Treatment of Contiguous Two-segment Cervical Degenerative Disc Diseases

STUDY DESIGN

A retrospective study.

OBJECTIVE

To compare the mid-term outcomes of hybrid surgery (HS) and anterior cervical discectomy and fusion (ACDF) for the treatment of contiguous two-segment cervical degenerative disc diseases.

SUMMARY OF BACKGROUND DATA

HS has become one of the most controversial subjects in spine communities, and the comparative studies of HS and ACDF in the mid- and long-term follow-up are rarely reported.

METHODS

From 2009 to 2012, 42 patients who underwent HS (n = 20) or ACDF (n = 22) surgery for symptomatic contiguous two-level cervical degenerative disc diseases were included. Clinical and radiological records, including Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), Visual Analogue Scale (VAS), local cervical lordosis, and range of motion (ROM), were reviewed retrospectively. Complications were recorded and evaluated.

RESULTS

Mean follow-up was 77.25 and 79.68 months in HS group and ACDF group, respectively (P > 0.05). Both in HS group and ACDF group, significant improvement for the mean JOA, NDI, and VAS scores was found at 2-week postoperation and at the last follow-up (P < 0.05). However, there were no significant differences between the two groups (P > 0.05). At the last follow-up, the range of motion (ROM) of superior adjacent segments in ACDF group was significantly larger than HS group (P < 0.05), while the ROM of C2-C7 was significantly smaller (P < 0.05). In the HS group, two (10%) sagittal wedge deformities, one (5%) heterotopic ossification, and one (5%) anterior migration of the Byran disc prosthesis were found. No symptomatic adjacent segment degeneration occurred in two groups.

CONCLUSION

HS appears to be an acceptable option in the management of contiguous two-segment cervical degenerative disc diseases. It yielded similar mid-term clinical improvement to ACDF, and demonstrated better preservation of cervical ROM. The incidence of postoperative sagittal wedge deformity was low; however, it can significantly reduce the cervical lordosis.

LEVEL OF EVIDENCE

4.

Cervical Burst Fracture in a Patient with Contiguous 2-Level Cervical Stand-Alone Cages

BACKGROUND

Cervical stand-alone interbody cages have seen increasingly wider use over the plate-and-screw construct in single-level anterior cervical discectomy and fusion (ACDF) in the treatment of cervical disc herniation and degenerative spondylotic conditions. Despite positive clinical outcomes, the efficacy and safety of using these devices in contiguous multilevel ACDF has remained controversial. This report discusses a burst fracture seen as a complication in multilevel cervical stand-alone cage use.

CASE DESCRIPTION

A 39-year-old woman with a history of C5-C6 and C6-C7 ACDF with contiguous stand-alone interbody cages 2 years prior, presented with recurrent arm and neck pain with myelopathy. Computed tomography scan revealed a burst fracture of the C6 vertebral body with retropulsion of fragments compressing the spinal cord.

CONCLUSIONS

This case suggests that use of cervical stand-alone cages in contiguous levels may cause late complications despite good instrumentation and illustrates the need for more careful consideration of technique selection in multilevel ACDF.