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

Facet joint loading after 1-, 2- and 3-level cervical disc arthroplasty: a comparison of spiked versus keeled baseplates

Background

The purpose of this study was to examine facet contact forces above, below, and at surgical index levels induced by artificial disc implantation and compare the results from spiked versus keeled baseplates comprising the arthroplasty device.

Methods

Human specimens from C2 to C7 were subjected to flexion, extension, and lateral bending prior to, and following random allocation to spiked or keeled cervical arthroplasty at the index (C5-C6), inferior (C6-C7), and superior (C4-C5) levels. Thin film force sensors were inserted unilaterally into the corresponding facets prior to intact testing. Force data was normalized to the minimum forces recorded during each loading mode under each condition, reported as (Max/Min) force ratio and subjected to a 1-way ANOVA with Dunnett's post-hoc tests for comparison to intact specimens.

Results

Under flexion, compared to intact, all levels displayed a significant reduction in force ratio following a 1- and 3-level implantation for the spiked baseplate device. An increase in force ratio was observed at the index level for a 2-level implantation but was mitigated with the completion of a superior device insertion. No statistical differences were noted for keeled devices. In extension, the spiked baseplate device reduced the force ratio for 1- and 2-level implantations. A 3-level insertion did not alter facet force ratios. For the keeled device, no statistical changes were noted. Lateral bending associated with spiked devices resulted in statistically reduced or nonsignificant changes in facet loading ratios. The keeled devices did not display significant changes to facet force ratios.

Conclusions

Implantation of multilevel disc devices can reduce or sustain unaltered facet loading conditions. In general, 3-level arthroplasty statistically reduced or does not increase facet force ratios compared to intact values. The use of spiked versus keel device baseplates is a clinical selection involving anterior/posterior placement and endplate degeneration conditions.

Correlation between axial symptoms and cervical sagittal alignment parameters in patients with two-level or three-level cervical spondylotic myelopathy: anterior cervcial discectomy and fusion versus hybird surgery

OBJECTIVE

To comparatively analyze the correlation between axial symptoms (AS) and cervical sagittal alignment parameters after anterior cervical discectomy and fusion (ACDF) and hybrid surgery (HS).

METHODS

From January 2018 to June 2023, 74 patients who underwent ACDF (n = 36) or HS (n = 38) for two-level or three-level cervical spondylotic myelopathy were retrospectively analyzed. The Visual Analogue Scale (VAS), Japanese Orthopedic Association (JOA), Neck Disability Index (NDI) were recorded to assess clinical outcomes. Cervical sagittal alignment parameters (Cobb's angle C2-7, C7 slope [C7S], and C2-7 sagittal vertical axis [C2-7 SVA]) were measured preoperatively, 3 days postoperatively, and at the last follow-up. The range of motion (ROM) of C2-7 and ROM of surgical segment were measured. The occurrence of AS was observed at the last follow-up. Logistic regression was used to analyze the correlation between postoperative AS and cervical sagittal alignment parameters.

RESULTS

Both in ACDF group and HS group, VAS, JOA and NDI scores showed significant improvements at 3-day postoperation and at the last follow-up (P < 0.05). However, there was no significant difference between the two groups (P > 0.05). The Cobb's angle C2-7 and C7S were significantly increased at 3 days postoperation compared with pre-operatively in both groups (P < 0.05). C2-7SVA was increased in both groups 3 days after surgery compared with pre-operatively, but there was no significant difference (P > 0.05). At the last follow-up, the ROM of C2-7 in ACDF group was significantly smaller than HS group (P < 0.05). The prevalence of postoperative AS in the ACDF group and HS group was 41.7 and 18.4%, respectively, with statistical difference between the two groups (P < 0.05). When simple Logistic regression analysis was used, the last Cobb's angle C2-7 (β = -0.088), the last C2-7SVA (β = 0.099) in ACDF group and the last C2-7SVA (β = 0.222) in HS group were all correlated with the occurrence of postoperative AS. When multiple Logistic regression analysis was used, only the last C2-7SVA (β = 0.181) in the HS group was positively correlated with the occurrence of postoperative AS.

CONCLUSIONS

Both ACDF and HS can achieve satisfied clinical outcomes. ACDF and HS can improve cervical sagittal balance to a certain extent, and HS is superior to ACDF in maintaining ROM. The decrease of the last Cobb's angle C2-7 and the increase of the last C2-7SVA may be related to the occurrence of AS after ACDF. The increase of the last C2-7SVA was an independent risk factor for the occurrence of AS after HS.

Comparison of the efficacy of ROI-C cage with Zero-P device in anterior cervical discectomy and fusion of cervical degenerative disc disease: a two-year follow-up study

Background

This study aimed to compare the clinical outcomes of Zero-P and ROI-C devices applied to anterior cervical discectomy and fusion (ACDF) surgery of cervical degenerative disc disease (CDDD).

Methods

From January 2020 and December 2020, 56 patients with CDDD who underwent ACDF using Zero-P or ROI-C were included in this retrospective study. The outcomes included visual analogue scale (VAS) score, Japanese Orthopedic Association (JOA) score, neck disability index (NDI) score, Cobb angle, dysphagia, and bone fusion rate. Dysphagia was assessed using the Bazaz grading system. The comparison of outcomes between the two groups was based on the 2-year follow-up time point, which was defined as the last follow-up visit.

Results

The Zero-P group included 16 males and 14 females, with a mean age of 56.2 (range, 35-65) years. The ROI-C group included 11 males and 15 females, with a mean age of 57.4 (range, 36-67) years. There was no significant difference in gender and mean age between the two groups. There were no significant differences in VAS score, JOA score, NDI score, Cobb angle, dysphagia, and bone fusion rate between two groups at the last follow up visit. In the Zero-P group, the duration of surgeries involving C3-4 or C6-7 segments was significantly longer than those including C4-5 or C5-6 segments (135.0 ± 19.0 vs. 105.6 ± 17.5 min, P < 0.05). In surgeries involving C3-4 or C6-7 segments, the operation time of ROI-C was significantly shorter than that of Zero-P (106.5 ± 19.5 vs.112.2 ± 20.5 min, P < 0.05). There were no significant differences in the dysphagia or cage subsidence rates between the Zero-P and ROI-C groups (P > 0.05). The Cobb angle in the last follow-up visit in the Zero-P group (24.4 ± 4.5°) was significantly higher than that in the ROI-C group (18.1 ± 2.3°) (P < 0.05).

Conclusions

ACDF using ROI-C device showed an efficacy similar to the Zero-P device, as well as a shorter operation time for surgeries involving C3-4 or C6-7 segments. However, ROI-C could cause more loss of Cobb angle over time, which could lead to uncomfortable symptoms.

Segment selection for fusion and artificial disc replacement in the hybrid surgical treatment of noncontiguous cervical spondylosis: a finite element analysis

Introduction: The treatment of skip-level cervical degenerative disease (CDD) with no degenerative changes observed in the intervening segment (IS) is complicated. This research aims to provide a reference basis for selecting treatment approaches for noncontiguous CDD. Methods: To establish accurate finite element models (FEMs), this study included computed tomography (CT) data from 21 patients with CDD (10 males and 11 females) for modeling. The study primarily discusses four cross-segment surgical approaches: upper (C3/4) anterior cervical discectomy and fusion (ACDF) and lower (C5/6) cervical disc arthroplasty (CDA), FA model; upper CDA (C3/4) and lower ACDF (C5/6), AF model; upper ACDF (C3/4) and lower ACDF (C5/6), FF model; upper CDA (C3/4) and lower CDA (C5/6), AA model. An initial axial load of 73.6 N was applied at the motion center using the follower load technique. A moment of 1.0 Nm was applied at the center of the C2 vertebra to simulate the overall motion of the model. The statistical analysis was conducted using STATA version 14.0. Statistical significance was defined as a p value less than 0.05. Results: The AA group had significantly greater ROM in flexion and axial rotation in other segments compared to the FA group (p < 0.05). The FA group consistently exhibited higher average intervertebral disc pressure in C2/3 during all motions compared to the AF group (p < 0.001); however, the FA group displayed lower average intervertebral disc pressure in C6/7 during all motions (p < 0.05). The AA group had lower facet joint contact stresses during extension in all segments compared to the AF group (p < 0.05). The FA group exhibited significantly higher facet joint contact stresses during extension in C2/3 (p < 0.001) and C6/7 (p < 0.001) compared to the AF group. Discussion: The use of skip-level CDA is recommended for the treatment of non-contiguous CDD. The FA construct shows superior biomechanical performance compared to the AF construct.

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.

A Novel Intraoperative Posture-Adjustment Apparatus for Correction of Cervical Lordosis in Anterior Cervical Surgery

OBJECTIVE

Cervical alignment is a crucial factor related to the success of anterior cervical surgical procedures. In patients with severe spinal cord compression, a traditional neck pillow (TNP) may not adequately correct cervical position during surgery. Therefore, the aim of this study was to introduce this innovative intraoperative posture-adjustment apparatus (IPAA), and explored its clinical and radiological results in cervical angle correction against TNP in patients who had undergone anterior cervical surgery.

METHODS

The clinical and radiological data of 86 patients who underwent anterior cervical surgery with a minimum follow-up period of 1 year were retrospectively reviewed. Of these, 58 patients underwent IPAA, whereas 28 underwent TNP. Radiological parameters such as the degree of C2-C7 lordosis (CL), functional spinal unit angle (FSUA), C7 slope (C7S), fusion rate, and adjacent segment disease (ASD) were recorded and compared between the groups. Clinical outcomes including the Japanese Orthopaedic Association (JOA), neck disability index (NDI), visual analogue scale (VAS) for neck and arm were recorded. Complications such as kyphosis, dysphagia, Braden Scale score, revision surgery, hematoma, cerebrospinal fluid leakage, wound infection, and deep venous thrombosis were also recorded. The independent t-test or Mann-Whitney U test was used to compare continuous data, and categorical variables were assessed using the Pearson's chi-square test or Fisher's exact test.

RESULTS

Compared with the pre-operative data, the post-operative CL, FSUA, and C7S were significantly increased in both groups. CL, FSUA, and C7S in the IPAA group (14.44 ± 4.94°, 7.36 ± 2.91°, 16.54 ± 4.63°) were significantly higher than those in the TNP group (7.17 ± 8.19°, 4.99 ± 5.36°, 14.19 ± 4.48°; P < 0.05). Although there were no significant differences between the groups in terms of VAS arm and JOA scores, the post-operative and final follow-up NDI and VAS neck scores in the IPAA group were significantly lower than those in the TNP group (p < 0.05). At the last follow-up, the TNP group had significantly more kyphotic patients than the IPAA group (2 vs. 0, p = 0,041). There was no significant difference between the groups in terms of fusion rate, ASD, or complications such as dysphagia, Braden's Scale score, revision surgery, hematoma, cerebrospinal fluid leakage, wound infection, or deep venous thrombosis.

CONCLUSION

IPAA was shown to be more effective than TNP in adjusting cervical alignment (CL, FSUA, and C7S). These findings suggest that IPAA could be used as an alternative way to TNP in neck setting and cervical alignment adjustment and IPAA could potentially improve clinical outcomes after anterior cervical surgery.

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.

Biomechanical effects of hybrid constructions in the treatment of noncontinuous cervical spondylopathy: a finite element analysis

BACKGROUND

Hybrid construction (HC) may be an ideal surgical strategy than noncontinuous total disc replacement (TDR) and noncontinuous anterior cervical discectomy and fusion (ACDF) in the treatment of noncontinuous cervical spondylopathy. However, there is still no consensus on the segmental selection for ACDF or TDR in HC. The study aims to analyse the effects of different segment selection of TDR and ACDF on cervical biomechanical characteristics after HC surgery.

METHODS

Twelve FEMs of C2-C7 were constructed based on CT images of 12 mild cervical spondylopathy volunteers. Two kinds of HC were introduced in our study: Fusion-arthroplasty group (Group 1), upper-level (C3/4) ACDF, and lower-level TDR (C5/6); Arthroplasty-fusion group (Group 2), upper-level (C3/4) TDR and lower-level ACDF (C5/6). The follow-load technique was simulated by applying an axial initial load of 73.6 N through the motion centre of FEM. A bending moment of 1.0 Nm was applied to the centre of C2 in all FEMs. Statistical analysis was carried out by SPSS 26.0. The significance threshold was 5% (P < 0.05).

RESULTS

In the comparison of ROMs between Group 1 and Group 2, the ROM in extension (P = 0.016), and lateral bending (P = 0.038) of C4/5 were significantly higher in Group 1 group. The average intervertebral disc pressures at C2/3 in all directions were significantly higher in Group 1 than those in Group 2 (P < 0.005). The average contact forces in facet joints of C2/3 (P = 0.007) were significantly more than that in Group 2; however, the average contact forces in facet joints of C6/7 (P < 0.001) in Group 1 group were significantly less than that in Group 2.

CONCLUSIONS

Arthroplasty-fusion is preferred for intervertebral disc degeneration in adjacent upper segments. Fusion-arthroplasty is preferred for patients with lower intervertebral disc degeneration or lower posterior column degeneration.

TRIAL REGISTRATION

This research was registered in Chinese Clinical Trial Registry (ChiCTR1900020513).

Kinematics of a cervical disc prosthesis implanted above or below one- and two-level fusions

Background

The theoretical advantages of hybrid constructs over multi-level fusion have been illustrated in clinical and biomechanical studies. However, there is no biomechanical data on hybrid constructs using load control analyses. There is also no clear data on whether there is a biomechanical difference if the arthroplasty is below or above a 1- or 2-level fusion. This work investigated the effect on segmental motion of having a cervical total disc arthroplasty implanted above or below a 1- or 2-level fusion.

Methods

Segmental motions of 16 C2-T1 cervical spine specimens were measured as the specimens were tested to 1.5Nm in axial rotation and in flexion-extension under compressive preload. Tests were conducted on intact specimens, and then after arthroplasty with a 1-level and 2-level fusion. 8 specimens were in test Group 1, where the hybrid configuration had a total disc arthroplasty above a 1- or 2-level fusion. The arthroplasty was below the 1- and 2-level fusion in Group 2. Load control and displacement control analyses were conducted to determine the effect of the hybrid configurations on segmental motion.

Results

In load control, compensatory motion increases were found at all non-instrumented cervical spine segments in flexion-extension and axial rotation. Flexion-extension and axial rotation ranges of motion at the total disc arthroplasty level were less than 1° different than intact.

In displacement control, there was no consistent pattern of compensatory motion. Range of motion at the arthroplasty level was within 3.5° of intact.

Conclusions

The total disc arthroplasty segmental level in a hybrid construct has similar amounts of motion as intact. This may shield the arthroplasty level and adjacent levels from supra-physiological motion and loading. These results suggest that a hybrid construct may be protective of adjacent segments, whether the total disc arthroplasty is above or below the fusion.

Diagnostic Investigations as a Basis for Optimising Surgical Management of Vertebrobasilar Insufficiency Syndrome

Vertebrobasilar insufficiency (VBI) is one of the most common forms of cerebrovascular pathology. The progression of the VBI, especially in the context of inadequate therapy, often leads to the formation of a persistent neurological deficits within the framework of dyscirculatory encephalopathy and the consequences of a stroke in the vertebrobasilar system. This study demonstrate the importance of objective methods of patient investigation to optimize the choice of the most effective methods of surgical treatment for VBI in cases of ineffective medical treatment. We have shown that the optimization of the diagnostic algorithm contributes to the correct individualized determination of types of surgical treatment for patients with VBI. It was found that, in addition to traditional diagnostic methods, the use of radiographic methods (ultrasound Doppler, multispiral computed tomography with contrast enhancement) is invaluable for choosing the tactics of surgical treatment. We propose a significant outcome indicator like the blood flow reactivity index to determine the postoperative improvement of blood flow in the vertebral arteries. In addition, the need to perform cerebral angiography and consultations with related specialists to exclude pathologies with a similar clinical picture is emphasized.

Anterior Approaches for Two-Level Cervical Degenerative Disease: A Comparative Study of at least 6-Year Follow-Up

Objective

To compare the clinical and radiogrincaphic results of a hybrid surgery (HS) and cervical artificial disc replacement (ADR) for contiguous two-level cervical spondylosis.

Methods

A total of 56 patients with contiguous two-level degenerative cervical spondylosis who underwent cervical HS and ADR via an anterior approach and completed at least 6 years of follow-up were included in this study. Patients were divided into two groups: group I, comprising 22 patients who underwent ADR, and group II, comprising 34 patients who underwent HS combined ADR and anterior cervical discectomy and fusion using a cage. Clinical outcomes were evaluated based on the visual analog scale (VAS) scores for arm pain, neck disability index (NDI), and modified MacNab criteria. Radiological parameters were assessed by measuring the bone fusion status, cervical range of motion (ROM C2-C7), heterotopic ossification (HO), adjacent segment disease (ASD) incidence, and fused segment height (FSH).

Results

The VAS scores and NDI significantly improved in both groups, without significant differences between the groups. The incidences of HO, ROM C2-C7, and FSH were similar between groups, without significant differences. New osteophyte formation and osteophyte enlargement at adjacent segments were more frequently found in the HS group; however, the difference was not significant.

Conclusion

Clinical results of this study showed that the clinical efficacy and radiological changes in HS were similar to those of ADR. HS can be an alternative procedure for the treatment of two-level cervical spondylosis.

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.

Is There a Relationship Between Bony Fusion After Anterior Cervical Discectomy and Fusion and Heterotopic Ossification After Cervical Disc Arthroplasty in Hybrid Surgery?

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

The aim of this study was to investigate the relationship between bony fusion after anterior cervical discectomy and fusion (ACDF) and heterotopic ossification (HO) after cervical disc arthroplasty (CDA) in hybrid surgery (HS).

SUMMARY OF BACKGROUND DATA

The mechanism of postoperative bone formation still remains unknown. It is considered a risk factor in CDA but is essential for a solid union in ACDF. With HS, we could directly study the mechanism and relationship of different forms of postoperative bone formation.

METHODS

Clinical data of 91 patients who had undergone consecutive two-level HS between January 2011 and January 2018 and with a minimum of 2-year follow-up was analyzed. HO was assessed based on McAfee's classifications, whereas fusion success was evaluated according the Food and Drug Administration approved criteria. Clinical outcomes and radiographic parameters were collected and used for the relevant comparisons.

RESULTS

HO was identified in 48.4% of patients (44/91). The fusion rates of patients in the HO group and the non-HO group at 3, 6, and 12 months postoperatively, and the final follow-up were 81.8% and 19.1%, 95.4% and 74.5%, 95.4% and 85.1%, and 97.7% and 93.6%, respectively. The fusion rates were significantly higher at 3 and 6 months after operation in the HO group than in the non-HO group (P < 0.05). Patients in both groups had significant improvements across all clinical outcomes at final follow-up.

CONCLUSION

There was a significant relationship between bony fusion and occurrence of HO after HS, suggesting that both bony fusion and HO are reflections of individual osteogenic capacity. However, a reliable predictor of postoperative bone formation is needed in the future to guarantee a solid bony fusion after ACDF and to further take full advantage of the motion-preserving from CDA.

LEVEL OF EVIDENCE

3.

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.

Is Cervical Disc Replacement Valuable in 3-Level Hybrid Surgery Compared with 3-Level Anterior Cervical Discectomy and Fusion?

BACKGROUND

Cervical degenerative disc disease is common in clinical practice. Surgery is among the most effective treatments for patients with cervical radiculopathy, myelopathy, or stenosis. Which treatment is the best option for multilevel cervical degenerative disc disease is controversial. Hybrid surgery, combined cervical disc replacement and anterior cervical discectomy and fusion, may be an alternative treatment for multilevel cervical degenerative disc disease.

METHODS

Sixty-four patients with 3-level hybrid surgery and 37 patients with 3-level anterior cervical discectomy and fusion were reviewed retrospectively. Clinical outcomes were based on visual analog scale, Neck Disability Index, 36-Item Short Form Survey, and Japanese Orthopaedic Association scores and Japanese Orthopaedic Association recovery rate. Radiologic assessments included range of motion (ROM) of C2-C7 and adjacent level and cervical lordosis of C2-C7. Perioperative parameters, fusion condition, and complications were assessed.

RESULTS

There were no statistical differences observed between the 2 groups for Japanese Orthopaedic Association, Neck Disability Index, or visual analog scale scores. The hybrid surgery group had better physical and mental 36-Item Short Form Survey scores than the fusion group at 1-year follow-up (physical component summary: 49.34 vs. 46.70, P = 0.012; mental component summary: 45.67 vs. 43.95, P = 0.004). ROM of C2-C7 and adjacent levels was less compromised in the hybrid group compared with baseline (64.60% vs. 51.34%, P < 0.001). Cervical lordosis was decreased with time in both groups but was acceptable at final follow-up, and both groups showed solid fusion.

CONCLUSIONS

Normal ROM and solid fusion were achieved at both arthroplasty and arthrodesis levels. ROM of replacement levels in different locations of the 3-level construct was acceptable.

Association between anterior bone loss and anterior heterotopic ossification in hybrid surgery

Background

Hybrid surgery (HS) has become an alternative procedure for the treatment of multilevel cervical degenerative disc disease with satisfactory outcomes. However, some adverse outcomes have recently emerged, such as heterotopic ossification (HO) and anterior bone loss (ABL). Furthermore, HO was found mostly located in the posterior and lateral of the cervical intervertebral disc space. The mechanism of anterior heterotopic ossification (AHO) formation may be different, and its relationship with ABL was uncertain.

Methods

Radiographical and clinical outcomes of ninety-seven patients who had undergone contiguous two-level HS between December 2010 and December 2017 and with a minimum of 2-year follow-up were analyzed. Postoperative radiographs were evaluated and compared to the initial postoperative films to determine the incidence of ABL and AHO.

Results

The overall incidence rate of ABL was 44.3% (43/97). It was identified in 70.6% of AHO cases (33.3% mild, 41.7% moderate, 25.0% severe) and 38.8% of non-AHO cases (38.7% mild, 45.2% moderate, 16.1% severe). A significant association between ABL and AHO occurrence was found (P = 0.016). There was no significant difference in prosthesis–endplate depth ratio or disc space angle change between the AHO group and the non-AHO group (P > 0.05). Compared with data preoperatively, clinical outcome scores significantly improved after surgery in both the AHO and non-AHO groups, with no significant differences between the two groups (P > 0.05).

Conclusion

ABL was common in HS, and it related to AHO. The formation of AHO could be an integral part of postoperative bone remodeling, as well as ABL.

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.

Does Fusion Affect Anterior Bone Loss in Adjacent Cervical Disc Arthroplasty in Contiguous Two-Level Hybrid Surgery?

OBJECTIVE

To investigate whether anterior bone loss (ABL) in cervical discarthroplasty (CDA) in 2-level hybrid surgery (HS) is affected by adjacent fusion in vivo compared with 1-level CDA alone.

METHODS

A total of 180 patients undergoing either a 1-level CDA or contiguous 2-level HS were retrospectively reviewed. The clinical and radiographic outcomes were collected preoperatively and at routine postoperative intervals of 1 week, 3, 6, and 12 months, and at the last follow-up. The initial and postoperative radiographs were compared to determine the incidence and degree of ABL.

RESULTS

ABL was identified in 68.7% of CDA cases (37.9% mild, 34.8% moderate, and 27.3% severe) and 44.0% of HS cases (54.1% mild, 27.0% moderate, and 18.9% severe). Sex, age, bone mineral density, operation time, blood loss, postoperative alignment, and range of movement at the arthroplasty segment were not related to the incidence of ABL. According to the logistic regression analysis results, ABL showed a significant correlation with the surgery type and body mass index. However, there was no significant difference in the incidence and degree of ABL with or without an adjacent fusion level. Compared with preoperative values, clinical outcome scores significantly improved after surgery in both the HS and CDA groups. No definite clinical effect associated with ABL was found.

CONCLUSIONS

ABL was common in both CDA and HS. Although HS had a lower incidence rate and degree than did CDA, the fusion location in HS did not affect the ABL of adjacent CDA.

Percutaneous posterior full-endoscopic cervical foraminotomy and discectomy: a finite element analysis and radiological assessment

Percutaneous posterior full-endoscopic cervical foraminotomy and discectomy (PECFD) is recognized as a safe, effective, and minimally invasive treatment for cervical spondylotic radiculopathy (CSR). However, the potential mechanisms of the degenerative changes and postoperative recurrence after PECFD are unclear. In this study, a finite element (FE) analysis and radiological assessment were performed to evaluate the biomechanical effects after PECFD. The FE model indicated that the ROM and IDP of C5-C6 increased significantly after PECFD in the extension loading. The radiological evaluation revealed that the extension ROM of C2-C7 and the operative level increased significantly at the one-year follow-up compared with that obtained preoperatively. Combining the FE results and radiological changes, we conclude that the increase in the ROM and IDP at the operative level in the extension loading is the potential cause of the degenerative changes and recurrences after PECFD surgery.

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.

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.

Artificial disc replacement in spine surgery

Total disc replacement (TDR) is an innovative procedure that has gained traction in spine surgery. A large amount of data in the literature report on the short-term outcomes of TDR surgery favorably. However, surgeons remain reluctant to opt for TDR surgery due to uncertainty of long-term outcomes. Recently, long term data regarding TDR surgery has become available, with some studies showing superior outcomes to fusion surgery. The goal of this review is to synthesize and clinically contextualize the recent literature on TDR surgery. This article also provides brief discussion of the biggest challenges currently facing disc arthroplasties and the ways in which they are being tackled.

Influence of Fusion on the Behavior of Adjacent Disc Arthroplasty in Contiguous 2-Level Hybrid Surgery In Vivo

OBJECTIVE

To investigate whether the behavior of disc arthroplasty in 2-level hybrid surgery (HS) was affected by adjacent fusion in vivo compared with cervical disc arthroplasty (CDA) alone.

METHODS

Seventy-nine patients undergoing either a 1-level CDA or contiguous 2-level HS were retrospectively reviewed. Radiologic assessments included segmental lordosis (SL), intervertebral disc height (IDH), changes in SL and IDH, range of motion (ROM) of the disc replacement and its adjacent segments, migration and subsidence of the prosthesis, heterotopic ossification (HO), and adjacent segment degeneration (ASD) adjacent to the arthroplasty level. Clinical features and outcome scores were also recorded.

RESULTS

Compared with 1-level CDA, the increased SL and IDH immediately after surgery in 2-level HS were more likely to be lost throughout the follow-up period. However, both groups generally maintained the SL and IDH of the arthroplasty segment postoperatively. Two-level HS did not exhibit hypermobility of the disc prosthesis and preserved preoperative ROM of the adjacent segment of the device. The HS group showed adverse effects on the prosthesis stability, but there was no significant difference in the number of cases of obvious migration or subsidence between the groups. The differences in HO, ASD, and clinical outcomes between the groups were not significant at the final follow-up.

CONCLUSIONS

Although the fusion in 2-level HS partially affected the behavior of adjacent disc arthroplasty compared with CDA alone, it did not cause severe complications and adverse clinical outcomes. However, large-scale and long follow-up trials are warranted.

Outcome Evaluation of Zero-Profile Device Used for Single-Level Anterior Cervical Discectomy and Fusion with Osteoporosis Compared without Osteoporosis: A Minimum Three-Year Follow-Up Study

OBJECTIVE

We compared the mid-term efficacy and safety of anterior cervical discectomy and fusion (ACDF) using a Zero-Profile device for cervical degenerative disc disease (CDDD) with and without osteoporosis.

METHODS

We performed a retrospective study of elderly patients with CDDD treated by single-level ACDF with a Zero-Profile device. The patients were divided into group A (osteoporosis) and group B (no osteoporosis) according to the bone mineral density. The clinical outcomes (Japanese Orthopaedic Association, neck disability index, visual analog scale, and short-form 36 scores), radiological outcomes (cervical lordosis and fusion rate), and complications were reviewed at each follow-up examination.

RESULTS

All procedures were successfully performed in all patients. The Japanese Orthopaedic Association, neck disability index, visual analog scale, and short-form 36 scores and cervical lordosis were significantly improved postoperatively in both groups (P < 0.05). However, no significant difference was found between the 2 groups at each follow-up point (P > 0.05). No significant difference was found in the fusion rate at 3 months postoperatively (group A, 88.9%; group B, 90.0%), dysphagia rate at 1 month postoperatively (group A, 11.1%; group B, 15.0%), or cage subsidence rate at the final follow-up visit (group A, 11.1%; group B, 10.0%; P > 0.05). All patients achieved solid fusion, and no patient had dysphagia at the final follow-up examination.

CONCLUSIONS

ACDF with the Zero-Profile device can be used as an effective and reliable treatment for single-level CDDD with osteoporosis.