Comparison between anterior and posterior decompression with instrumentation for cervical spondylotic myelopathy: sagittal alignment and clinical outcome

Comparison of anterior and posterior approaches for functional improvement in cervical myelopathy: A systematic review and meta-analysis of 33,025 patients

Background

Cervical myelopathy is caused by pressure on the spinal cord in the neck, leading to pain, numbness, and balance issues. Surgery aims to decompress the spinal cord, with different approaches; anterior, posterior, or both depending on specifies. This systematic review and meta-analysis aimed to compare the risks and benefits of anterior and posterior surgical techniques.

Methods

Adhering to the PRISMA guidelines, we conducted a systematic search across the databases including PubMed, Scopus, and Web of Science for studies comparing anterior and posterior surgical approaches for cervical myelopathy. Studies that met our predefined inclusion criteria were selected by 2 independent reviewers. The methodological quality of the selected studies was assessed using NOS and Rob-2 tools and analysis was done using the Review Manager tool. One RCT and 22 cohort studies including 33,025 patients were included in the analysis.

Results

The anterior approach was associated with better neurological recovery and a greater improvement in Cobb's angle with MD of 4.18 (95%CI: 0.38, 7.91, p=.03), and 6.91 (95%CI: 1.85, 11.97, p=.007), respectively. The anterior approach showed a statistically significant decrease in VAS, and NDI scales with MD of -0.44 (95%CI: -0.75, -0.12, p=.007), and -1.91 (95%CI: -3.74, -0.09, p=.04), respectively as compared to posterior approach.

Conclusions

Studies suggest that an anterior approach for cervical myelopathy may improve nerve function, correct spinal curvature more effectively, and lead to fewer complications, less pain, reduced blood loss, and a shorter hospital stay compared to a posterior approach.

Safety and Efficacy of Anterior Cervical Corpectomy and Reconstruction With Expandable Cages for Treatment of Cervical Myelopathy-Focusing on Stand-Alone Cages: A Systematic Review and Meta-Analysis

Study DesignSystematic review and Meta-analysis.ObjectivesThis study aims to evaluate the efficacy, postoperative outcomes, and potential complications of using expandable cages in cervical spine surgery.MethodsA comprehensive search was performed across Medline, Scopus, Web of Science, Cochrane, and Embase up to May 22, 2023. Meta-analyses and subgrouping analyses were performed using "OpenMetaAnalyst" and R software to analyze efficacy outcomes and complications. The assessment of heterogeneity utilized the i2 and chi-squared tests, applying the random effect model.ResultsThirty studies were included, with 22 eligible for meta-analysis. The pooled data showed a significant improvement in the Cobb angle, Nurick's score and modified Japanese Orthopedic Association (mJOA) score. The pooled stability rate post-surgery was 0.94 based on 7 studies, but the stand-alone cages showed a lower stability rate (0.83). Fusion rate showed high success at 0.94 across 14 studies but also the fusion rate in the stand-alone group was lower (0.89) with substantial heterogeneity (I2 = 91.81%) suggests that stand-alone cages may not consistently achieve the same level of fusion as cages with anterior plating (fusion rate of 0.98, I2 = 0%). Dysphagia was observed in 16% of patients, and hardware-related issues were reported in 9% of cases.Conclusionsexpandable cages offer significant advantages in terms of fusion, stability, and neurological recovery. In particular, stand-alone expandable cages were associated with higher rates of complications, including dysphagia, subsidence, and hardware failure, compared to cages with anterior plating.

Comparison of Anterior Surgery Versus Posterior Surgery for the Treatment of Multilevel Cervical Spondylotic Myelopathy: A Meta-Analysis

STUDY DESIGN

A meta-analysis.

OBJECTIVE

To evaluate the impact of anterior versus posterior surgical approaches on outcomes in MCSM.

BACKGROUND

Multilevel cervical spondylotic myelopathy (MCSM) is the most common cause of spinal cord dysfunction, and the clinical effectiveness of anterior versus posterior surgical approaches remains elusive.

METHODS

A comprehensive search was conducted across electronic databases, including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, to evaluate the effects of anterior surgery versus posterior surgery on outcomes, such as Japanese Orthopedic Association (JOA) score, neck disability index (NDI) score, neck visual analog scale (VAS), blood loss, operation time, length of stay, cervical range of motion, cervical Cobb angle, and complications. The baseline characteristics of the included studies were assessed using the Newcastle-Ottawa Scale score to measure the risk of bias.

RESULTS

In this meta-analysis, 14 retrospective and 6 prospective cohort studies, involving 2712 patients, were included. The analysis indicated no significant difference between the 2 groups in preoperative JOA score, postoperative JOA score, JOA recovery rate, postoperative neck VAS score, operation time, preoperative range of motion (ROM), or SF-36 score (P=0.95, 0.15, 0.20, 0.31, 0.94, 0.33, and 0.43, respectively). However, the NDI score and blood loss were significantly lower in the anterior surgery group compared with the posterior surgery group (P<0.04, P=0.0003). The anterior surgery group was also associated with shorter length of stay (P<0.00001), while had higher rates of complications (P=0.04). C2-7 Cobb angle and postoperative ROM were significantly lower in the anterior surgery group than those in the posterior surgery group (P=0.0002 and 0.01, respectively).

CONCLUSION

This meta-analysis found no clear advantage of 1 surgical approach over the other for MCSM in terms of neurological function recovery, as measured by JOA scores. The anterior approach was associated with improved NDI scores, lower blood loss, shorter length of stay, and better recovery of cervical lordosis, accompanied by limited postoperative mobility. Careful consideration should be given to potential complications, including dysphagia with the anterior surgery, axial pain, and C5 palsy with the posterior surgery.

Cervical Alignment and Range of Motion Change after Anterior 3-Level Hybrid Surgery Compared with Cervical Laminoplasty: A Matched Cohort Study

OBJECTIVES

Cervical alignment and range of motion (ROM) changes after cervical spine surgery are related to cervical biomechanical and functions. Few studies compared these parameters between posterior laminoplasty and anterior 3-level hybrid surgery incorporating anterior cervical discectomy and fusion (ACDF) with cervical disc replacement (CDR). This study is aimed to detect the differences of cervical alignment and ROM changes of the two surgeries in a matched-cohort study.

METHODS

From January 2018 and May 2020, 51 patients who underwent 3-level hybrid surgery incorporating ACDF with ACDR were included. A 1:1 match of the patients who underwent cervical laminoplasty based on age, gender, duration of symptoms, body mass index, and cervical alignment type was utilized as control group. General data (operative time, blood loss, etc.), Japanese Orthopaedic Association (JOA) score, VAS (Visual Analog Score), NDI (The Neck Disability Index), cervical sagittal alignment, and cervical range of motion (ROM) were recorded and compared.

RESULTS

Both groups gained significant improvement in JOA, VAS, NDI scores postoperatively (p < 0.05). Cervical alignment significantly increased in hybrid group and decreased in control group after surgeries (p < 0.001). ROM decrease was similar in two groups. For cervical lordosis, though cervical alignment angle in control group decreased, the final follow-up cervical alignment and cervical alignment changes were not significantly different between hybrid and control groups. For cervical non-lordosis, cervical alignment decreased in control group while increased in hybrid group. At final follow-up, cervical alignment and the changes between the two groups were significantly different. Both control group and hybrid group had similar ROM decrease after the surgery no matter whether there was cervical lordosis or non-lordosis. Hybrid surgery showed cervical alignments significantly improved and similar ROM preservation compared with control group at final follow-up both for 1-level and 2-level disc replacement subgroups.

CONCLUSIONS

The hybrid surgery demonstrated advantages of preserving cervical alignment and gaining similar cervical ROM preservation compared with cervical laminoplasty, especially for cervical non-lordosis. Given the importance of restoring lordotic cervical alignment, hybrid surgery may be preferred over laminoplasty to treat multilevel cervical disc herniation.

Comparison of Three Grafting Options for Anterior Cervical Corpectomy and Fusion: A Retrospective 3-Arms Case Control Study

BACKGROUND

Anterior cervical corpectomy and fusion achieves foraminal radicular and central medullary decompression and spinal stabilization in staged lesions. Many bone graft materials have been developed for the reconstruction of cervical lordosis and the restoration of intervertebral height after corpectomy. The PolyEtherKetoneEtherKetoneKetone (PEKEKK) is a semicrystalline thermoplastic polymer that can be reinforced with carbon fibers to create long and highly fenestrated rectangular cervical cages for corpectomy. This study aimed to evaluate the radiological outcomes of an innovative PEKEEKK cage compared with others grafting options.

METHODS

Forty-five consecutive patients who underwent surgery with PEKEKK cages between 2017 and 2019 at a spine institution, were matched with 15 patients with a titanium mesh cylindrical cage (TMC) and 15 patients with a tricortical structural iliac bone graft. The restoration of vertebral height and cervical lordosis postoperatively, and subsidence of the construct were evaluated. Complications were reported.

RESULTS

The minimal follow-up was 5.1±2years. A better, but nonsignificant, postoperative gain in height was observed for PEKEKK (+8.1 ± 20%) and TMC cages (+8.2 ± 16%) than for iliac crest autograft reconstruction (+2.3 ± 15%, P = 0.119). The mean subsidence at the last follow-up was greater for TMC cages (-10.2 ± 13%), but was not significant, with -6.1 ± 10% for PEKEKK cages and -4.1 ± 7% for iliac crest autografts (P = 0.223). The gain in segmental cervical lordosis was significant (P < 0.001) and remained stable in all the groups.

CONCLUSIONS

Although an improvement in radiologic anatomical parameters can be achieved with all cage groups, the PEKEKK cage can be considered as a safe alternative for reducing subsidence.

Comparing two surgical approaches for treating multilevel cervical spondylotic myelopathy: A meta-analysis

PURPOSE

This meta-analysis aims to evaluate the therapeutic efficacy of anterior versus posterior surgical approaches for multisegment cervical spondylotic myelopathy (MCSM).

METHODS

Eligible studies published between the period of January 2001 and April 2022 and comparing the anterior and posterior surgical approaches for treating cervical spondylotic myelopathy were retrieved from the PubMed, Web of Science, Embase, and Cochrane databases.

RESULTS

A total of 17 articles were selected based on the inclusion and exclusion criteria. This meta-analysis failed to show any significant difference in the duration of surgery, the hospitalization time, or the improvement in the Japanese Orthopedic Association score between the anterior and posterior approaches. The anterior approach, however, exhibited increased efficacy in the improvement of the neck disability index, reduction in the visual analog scale for cervical pain, and improvement in the cervical curvature compared with the posterior approach.

CONCLUSION

Bleeding was also less with the anterior surgical approach. The posterior approach provided a significantly higher range of motion of the cervical spine and showed fewer postoperative complications compared with the anterior approach. While both the surgical approaches have good clinical outcomes and show postoperative neurological function improvement, the meta-analysis shows that both anterior and posterior approaches have certain merits and shortcomings. A meta-analysis of a larger number of randomized controlled trials with longer follow-up can conclusively determine which of the surgical approaches is more beneficial in the treatment of MCSM.

Cervical vertebral body replacement using a modern in situ expandable and angulable corpectomy cage system: early clinical and radiological outcome

PURPOSE

Vertebral body replacement (VBR) cages are commonly implanted to reconstruct the cervical vertebrae in cases of tumour, trauma, spondylodiscitis, and degeneration. Expandable cages have been widely used for this purpose; however, the lacking congruence at the implant-bone interface and consequent implant displacement were considered as a serious drawback of such systems. Aim of this study is to evaluate the early clinical and radiological outcome of a modern in situ not only expandable but also angulable cervical corpectomy cage system.

METHODS

A total of 42 patients who underwent a single or multilevel cervical VBR procedure were included and retrospectively evaluated in this single-centre case series. The neurological status was assessed using American Spinal Injury Association (ASIA) score. Complications were categorized into surgical (including implant-associated) and general medical. Radiographic parameters included regional angulation, segmental height, and coronal alignment.

RESULTS

Mean age was 59.5 ± 20.6 years. The recorded ASIA score improved postoperatively by 10 points (p  0.0001). Surgical including implant-associated complication rates were 19.05%. Radiographic evaluation showed a height gain of 11.2 mm (p < 0.0001), lordotic correction of 7° (p < 0.0001), and coronal alignment of 3° (p < 0.0001). At the last follow-up, loss of angulation correction of 1.9° (p  0.0002), subsidence of 1.92 mm (p  0.0006), and fusion rates of 68.42% were observed.

CONCLUSIONS

The use of an in situ angulable and expandable cage system in cervical VBR seems to offer better results compared to conventional static or expandable cages regarding segmental height gain, lordotic correction, and clinical improvement as well as low complication and revision rates. Significant height gain in multilevel surgeries is associated with higher rates of implant-associated complications.

Predicting surgical outcome and sagittal alignment change in patients with cervical spondylosis and degenerative kyphosis after anterior cervical discectomy and fusion

The aim of this study was to forecast the risk factors of poor outcomes and postoperative loss of lordosis or recurrence of kyphosis. In this retrospective study, 101 patients with cervical spondylosis and preoperative kyphosis who underwent anterior cervical discectomy and fusion (ACDF) were enrolled, between June 2015 and June 2019. Patients were grouped according to the recovery rate of Japanese Orthopaedic Association (JOA) score whether more than 50%, and the change of postoperative cervical Cobb angle. There were 22 cases with less than 50% of recovery rate and 35 cases with the worsening of postoperative sagittal alignment (WPSA). Multivariate linear-regression analysis was conducted with the data. Advanced age (p = 0.019), longer duration of symptoms (p = 0.003) and loss of local Cobb angle (LCA) after surgery (p = 0.031) was significantly associated with a poor clinical outcome. A whole kyphosis (p = 0.009), aggravated neck pain after surgery (p = 0.012), preoperative lower thoracic 1 (T1) (p < 0.001), bigger change of C2-7 sagittal vertical axis (SVA) (p = 0.008) and adjacent segment degeneration (ASD) (p = 0.024) was significantly associated with the WPSA. Preoperative health education, nutritional support and early postoperative rehabilitation intervention, in perioperative period, were recommended for patients with advance age, longer duration of symptoms, whole cervical kyphosis and lower T1. Postoperative sagittal malalignment was related to neck pain and ASD after surgery.

Cervical sagittal alignment changes following anterior cervical discectomy and fusion, laminectomy with fusion, and laminoplasty for multisegmental cervical spondylotic myelopathy

OBJECTIVE

Cervical sagittal alignment changes (CSACs) influence outcomes and health-related quality-of-life. Anterior cervical discectomy and fusion (ACDF), laminectomy with fusion (LCF), and laminoplasty (LP) are common treatments for multisegmental cervical spondylotic myelopathy; however, these approaches need to be compared.

METHODS

Our study included 167 patients who underwent ACDF, LCF, or LP. Patients were divided into four groups according to C2-C7 Cobb angle (CL): kyphosis (CL < 0°), straight (0° ≤ CL < 10°), lordosis (10° ≤ CL < 20°), and extreme lordosis (20° ≤ CL) groups. CSACs consist of two parts. CSAC from the preoperative period to the postoperative period is surgical correction change (SCC). CSAC from the postoperative period to the final follow-up period is postoperative lordosis preserving (PLP). Outcomes were evaluated using the Japanese Orthopaedic Association score and the neck disability index.

RESULTS

ACDF, LCF, and LP had equivalent outcomes. ACDF had greater SCC than LCF and LP. During follow-up, lordosis decreased in the ACDF and LCF groups but increased in the LP group. For straight alignment, ACDF had greater CSAC and greater SCC than the LCF and LP groups but similar PLP. For lordosis alignment, ACDF and LP had positive PLP, and LCF had negative PLP. For extreme lordosis, ACDF, LP, and LCF had negative PLP; however, cervical lordosis in the LP group was relatively stable during follow-up.

CONCLUSIONS

ACDF, LCF, and LP have different CSAC, SCC, and PLP according to a four-type cervical sagittal alignment classification. Preoperative cervical alignment is an important consideration in deciding the type of surgical treatment in CSM.

Perioperative Complications of Surgery for Degenerative Cervical Myelopathy: A Comparison Between 3 Procedures

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

To compare the perioperative complications of propensity score-matched cohorts of patients with degenerative cervical myelopathy (DCM), who were treated with anterior cervical discectomy and fusion (ACDF), posterior laminectomy with fusion, or laminoplasty.

METHODS

The Humana PearlDiver Patient Record Database was queried using the International Classification of Diseases (ICD-9 and ICD-10) and the Current Procedural Terminology (CPT) codes. Propensity score-matched analysis was done using multiple Chi-squared tests with Bonferroni correction of the significance level.

RESULTS

Cohorts of 11,790 patients who had ACDF, 2,257 patients who had posterior laminectomy with fusion, and 477 patients who had laminoplasty, were identified. After propensity score matching, all the 3 groups included 464 patients. The incidence of dysphagia increased significantly following ACDF compared to laminoplasty, P < 0.001, and in laminectomy with fusion compared to laminoplasty, P < 0.001. The incidence of new-onset cervicalgia was higher in ACDF compared to laminoplasty, P = 0.005, and in laminectomy with fusion compared to laminoplasty, P = 0.004. The incidence of limb paralysis increased significantly in laminectomy with fusion compared to ACDF, P = 0.002. The revision rate at 1 year increased significantly in laminectomy with fusion compared to laminoplasty, P < 0.001, and in ACDF compared to laminoplasty, P < 0.001.

CONCLUSIONS

The incidence of dysphagia following laminectomy with fusion was not different compared to ACDF. Postoperative new-onset cervicalgia and revisions were least common in laminoplasty. The highest rate of postoperative limb paralysis was noticed in laminectomy with fusion.

Complications associated with subaxial placement of pedicle screws versus lateral mass screws in the cervical spine (C2-T1): systematic review and meta-analysis comprising 4,165 patients and 16,669 screws

Lateral mass screw (LMS) and cervical pedicle screw (CPS) fixation are among the most popular techniques for posterior fusion of the cervical spine. Early research prioritized the LMS approach as the trajectory resulted in fewer neurovascular complications; however, with the incorporation of navigation assistance, the CPS approach should be re-evaluated. Our objective was to report the findings of a meta-analysis focused on comparing the LMS and CPS techniques in terms of rate of various complications with inclusion of all levels from C2 to T1. We conducted a systematic review of PubMed and EMBASE databases with final inclusion criteria focused on identifying studies that reported outcomes and complications for either the CPS or LMS technique. These studies were then pooled, and statistical analyses were performed from the cumulative data. A total of 60 studies comprising 4165 participants and 16,669 screws placed within the C2-T1 levels were identified. Within these studies, the LMS group had a significantly increased odds for lateral mass fractures (odds ratio [OR] = 43.2, 95% confidence interval [CI] = 2.62-711.42), additional cervical surgeries (OR = 5.56, 95%CI = 2.95-10.48), and surgical site infections (SSI) (OR = 5.47, 95%CI = 1.65-18.16). No other significant differences between groups in terms of complications were identified. Within the subgroup analysis of navigation versus non-navigation-guided CPS placement, no significant differences were identified for individual complications, although collectively significantly fewer complications occurred with navigation (OR = 5.29, 95%CI = 2.03-13.78). The CPS group had significantly fewer lateral mass fractures, cervical revision surgeries, and SSIs. Furthermore, navigation-assisted CPS placement was associated with a significant reduction in complications overall.

Anterior and Posterior Approaches for 4-Level Degenerative Cervical Myelopathy: Low-Profile Cage Versus Cervical Pedicle Screws Fixation

(1) Background: The choice of surgical access for 4-level degenerative cervical myelopathy (DCM) remains controversial, and the clinical and radiological outcomes of anterior surgery using a low-profile cage (Low-P) versus posterior surgery using cervical pedicle screw fixation (CPS) have not been compared. (2) Methods: This is a retrospective controlled study conducted between January 2019 and June 2021 of 72 patients with 4-level DCM who underwent ACDF using a low-profile cage (n = 39) or laminectomy and instrument fusion using CPS (n = 33). The minimum follow-up time was 12 months. The outcomes were C2−7Cobb angle, C2−7sagittal vertical axis (SVA) fusion rate, the Japanese Orthopedic Association (JOA) score, pain visual analog scale (VAS), neck disability index (NDI), and complications. (3) Results: Both anterior and posterior procedures significantly improved the patients’ quality-of-life parameters. Anterior cervical convexity and SVA significantly increased in both groups, but the SVA was greater in the posterior group than in the anterior group (p < 0.001). The C2−7 Cobb angle significantly improved in both groups postoperatively, and at the final follow-up, there was a slight but nonsignificant reduction in cervical lordosis in both groups (p = 0.567). There was a longer operative time, less intraoperative blood loss, and reduced mean hospital stay in the anterior group compared to the posterior group, with two cases of postoperative hematoma requiring a second operation, two cases of axial pain (AP), five cases of dysphagia, two cases of c5 palsy in the anterior group, and four cases of axial pain, and three cases of c5 palsy in the posterior group. According to Bridwell fusion grade, anterior fusion reached grade I in 28 cases (71.8%) and grade II in 10 cases (25.6%) in the anterior group, and posterior fusion reached grade I in 25 cases (75.8%) and grade II in 8 cases (24.2%) in the posterior group. (4) Conclusions: There was no difference between the anterior and posterior surgical approaches for MDCM in terms of improvement in neurological function. Posterior surgery using CPS achieved similar recovery of cervical anterior convexity as anterior surgery with a shorter operative time but was more invasive and had a greater increase in SVA. The use of Low-P in anterior surgery reduced the incidence of dysphagia and cage subsidence and was less invasive, but with a longer operative time.

Variation in Prevertebral Soft Tissue Swelling after Staged Combined Multilevel Anterior-Posterior Complex Cervical Spine Surgery: Anterior Then Posterior (AP) versus Posterior Then Anterior-Posterior (PAP) Surgery

The influence of the sequence of surgery in the development of prevertebral soft tissue swelling (PSTS) in staged combined multilevel anterior-posterior complex spine surgery was examined. This study was conducted as a retrospective study of patients who underwent staged combined multilevel anterior-posterior complex cervical spine surgery from March 2014 to February 2021. Eighty-two patients were identified, of which fifty-seven were included in the final analysis after screening. PSTS was measured from routine serial monitoring lateral cervical radiographs prior to and after surgery for five consecutive days at each cervical level from C2 to C7 in patients who underwent anterior then posterior (AP) and posterior then anterior-posterior (PAP) surgery. The mean PSTS measurements significantly differed from the preoperative to postoperative monitoring days at all cervical levels (p = 0.0000) using repeated measures analysis of variance in both groups. PSTS was significantly greater in PAP than in AP at level C2 on postoperative day (POD) 1 (p = 0.0001). PSTS was more prominent at levels C2-4 during PODs 2-4 for both groups. In staged combined multilevel anterior-posterior complex spine surgery, PSTS is an inevitable complication. Therefore, surgeons should monitor PSTS after surgery when performing anterior-posterior complex cervical spine surgery, especially in the immediate postoperative period after PAP surgery.

Anterior Cervical Corpectomy and Fusion for Degenerative Cervical Spondylotic Myelopathy: Case Presentation With Surgical Technique Demonstration and Review of Literature

Anterior cervical corpectomy and fusion (ACCF) provides an extensive decompression and provides a large surface area for fusion in patients presenting with cervical spondylotic myelopathy. Unfortunately, this procedure is a more difficult spinal surgery to perform (compared with a traditional anterior cervical discectomy and fusion) and has a higher incidence of overall complications. In literature, ACCF has functional outcomes that seem clinically equivalent to those for multilevel anterior cervical discectomy and fusion, especially when contained to 1 vertebral body level, and in cases, for which both posterior and anterior procedures would be appropriate surgical options, may provide greater long-term clinical benefit than posterior fusion or laminoplasty. In this manuscript, we summarize the indications and outcomes following ACCF for degenerative cervical spondylotic myelopathy. We then describe a case presentation and associated surgical technique with a discussion of complication avoidance with this procedure.

Cost analysis comparison between anterior and posterior cervical spine approaches

Background

The costs of cervical spine surgery have steadily increased. We performed a 5-year propensity scoring-matched analysis of 276 patients undergoing anterior versus posterior cervical surgery at one institution.

Methods

We performed propensity score matching on financial data from 276 patients undergoing 1-3 level anterior versus posterior cervical fusions for degenerative disease (2015-2019).

Results

We found no significant difference between anterior versus posterior approaches for hospital costs ($42,529.63 vs. $45,110.52), net revenue ($40,877.25 vs. $34,036.01), or contribution margins ($14,230.19 vs. $6,312.54). Multivariate regression analysis showed variables significantly associated with the lower contribution margins included age (β = -392.3) and length of stay (LOS; β = -1151). Removing age/LOS from the analysis, contribution margins were significantly higher for the anterior versus posterior approach ($17,824.16 vs. $6,312.54, P = 0.01).

Conclusion

Anterior cervical surgery produced higher contribution margins compared to posterior approaches, most likely because posterior surgery was typically performed in older patients requiring longer LOS.

Mechanisms of compensatory for cervical lordosis changes after laminectomy with fusion

Background

The compensatory mechanisms for cervical lordosis change after laminectomy with fusion was not clear. The objective of this study was to evaluate the compensatory behaviors for cervical lordosis change after laminectomy with fusion.

Methods

This was a retrospective radiological analysis of 43 patients with cervical spondylotic myelopathy who underwent laminectomy with fusion (LCF). The following cervical parameters were measured: C2-7 Cobb angle (C2-7), occiput-C2 angle (O-C2), the cervical sagittal vertical axis (cSVA), and T1 slope (T1S). The difference was calculated for all angle parameters between the two time points using the following formula: the amount of change (Δ) = (value at the follow-up)—(preoperative value). Non-parametric tests and the t-test were used to compare the difference. The Pearson correlation test was performed, and stepwise multiple regression analysis was performed to determine the best correlation between ∆cSVA and ∆T1S.

Results

The mean age of 43 patients was 65.51 ± 9.80 years. All patients were classified into two subgroups based on ΔcSVA: Group M (maintained) and, Group I (increased). The preoperative O-C2, C2-7, T1S, and cSVA were similar between Group M and group I (p = 0.950, p = 0.731, p = 0.372, and p = 0.152, respectively). Postoperative O-C2 and postoperative cSVA were significantly different (p = 0.036 and p = 0.004, respectively). ∆O-C2, ∆T1S and ∆cSVA were significantly different between the two groups (p = 0.006, p = 0.000, and p = 0.000, respectively). ΔcSVA had significant correlations with ΔO-C2 neutral angle (r = 0.377) and ΔT1S (r = 0.582). A linear regression equation was established: ΔcSVA = 0.602 + 0.103 * ΔT1S (R = 0.582, R² = 0.339).

Conclusions

The decrease of TIS should be the first and foremost compensation for the loss of lordosis in C2-7 segments after LCF. When the change of T1S alone can not prevent the deterioration of cervical sagittal balance, further increases in the O-C2 segment occur.

ACDF and posterior spinal fusion revision for posterior nonunion with deformity, myelopathy, and osteoporosis in an 87-year-old: A case report and literature review

Introduction

Cervical spondylotic myelopathy (CSM) is a spinal degenerative disorder that can ultimately lead to compression of the vertebral column with neurological sequelae. Although CSM is the most common spine pathology in the elderly American population, it remains a challenging disorder to treat among older patients.

Case presentation

We report an 86 year old female patient with CSM with a history of posterior cervical fusion attempt on C3-C6 that progressed to C3-C6 nonunion with loose instrumentation. The patient had severe osteoporosis. With these indications, the patient underwent a combined anterior-posterior decompression and fusion (CAPDF) consisting of anterior cervical discectomy and fusion (ACDF) of the C3-C5, corpectomy of C6 and C7 with off FDA label use of polymethyl methacrylate augmentation (PMMA) fixation of T1 screws anteriorly for C3-T1 plate fixation and second stage instrumented posterior spinal fusion (PSF) of C3-T3. The patient had a successful fusion and reduction of her cervical spine pain with preservation of her neurological status.

Discussion

We report this case of multi-stage combined anterior and posterior fusion as a corrective measure for pseudarthrosis of a prior posterior cervical spinal fusion attempt.

Conclusion

In the event of posterior spinal fusion instrumentation failure in patients with severe osteoporosis, combined multi-stage anterior-posterior fusion is a viable corrective intervention in octogenarians. This case also illustrated the utility of using PMMA for anterior cervical plate and screw stabilization in osteoporotic bone. The authors are not aware of the prior use of PMMA for screw fixation augmentation in the anterior cervical spine.

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Combined anterior-posterior cervical fusion for cervical spondylotic myelopathy and pseudarthrosis of prior intended fusion.

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Polymethylmethacrylate (PMMA) demonstrated as safe and effective for screw purchase augmentation in anterior cervical spine

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Multi stage spinal fusion to limit prolonged one-stage anesthesia identified to be safe and effective for this patient

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Management of cervical fusion pseudarthrosis in the setting of osteoporosis in the elderly

Use of a smartphone leveling application to optimize cervical thoracic alignment prior to posterior instrumentation

OBJECTIVE

Posterior cervical decompression and instrumentation (PCDI) is often associated with increase in sagittal balance and loss of lordosis. Here we propose a simple method of surgical positioning utilizing a readily available smartphone application to optimize cervical thoracic alignment in PCDI. The intent of this optimization is to minimize losses in lordosis and increases in sagittal balance.

METHODS

For patients since 2019, the position of the head was adjusted so that the occiput to thoracic spine was aligned and the chin brow angle was parallel to the rails of the surgical table utilizing a leveling smart application (RIDGID Level). Patients before 2019 who were not optimized were compared.

RESULTS

There were 13 patients in the nonoptimized cohort (NOC) and 20 in the optimized cohort (OC). In the NOC, the change in lordosis was -7° (p=0.016) and change in C2-SVA was 7 mm (p<0.001) from preoperative to postoperative values. In the OC, the change in lordosis was 2° (p=0.104) and change in C2-SVA was 2 mm (p=0.592) from preoperative to postoperative values. Between the NOC and OC cohorts, the changes in lordosis and sagittal balance between cohorts were significant (p=0.002 and p=0.001 respectively). There was no significant difference in clinical outcomes as measured by JOA or complication rates.

CONCLUSION

Positioning of the patient in preparation for PCDI can influence post-operative lordosis and sagittal balance. Using the leveling application on the smart phone (RIDGID Level), is a rapid and free alternative for the maintenance of lordosis and sagittal balance during instrumentation in the operating room.

Cervical alignment in the obese population following posterior cervical fusion for cervical myelopathy

STUDY DESIGN

Retrospective cohort study OBJECTIVE: The aim of this study was to investigate the effect of body mass index (BMI) on the reoperation rate and cervical sagittal alignment of patients who underwent posterior cervical decompression and fusion for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Cervical sagittal balance has been correlated with postoperative clinical outcomes. Previous studies have shown worse postoperative sagittal alignment and higher reoperation rates in patients with high BMI undergoing anterior decompression and fusion. Similar evidence for the impact of obesity in postoperative sagittal alignment for patients with (CSM) undergoing posterior cervical decompression and fusion (PCF) is lacking.

METHODS

A retrospective analysis of 198 patients who underwent PCF for cervical myelopathy due to degenerative spine disease was performed. Demographics, need for reoperation, and perioperative radiographic parameters were collected. Cervical lordosis (CL), C2-7 sagittal vertical axis (SVA), and T1 slope (T1S) was measured on standing lateral radiographs. Comparative analysis of the patient cohort was performed by stratifying the sample population into three BMI categories (<25, 25-30, ≥30).

RESULT

Of the 198 patients that met inclusion criteria, 53 had BMI normal (<25), 65 were overweight (25-30), and 80 were obese (≥30). Mean SVA increased postoperatively in all groups, 4 mm in the normal group, 13 mm in the overweight group, and 13 mm in the obese group (p = 0.003). There was no significant difference in the postoperative change of cervical lordosis or T1 slope between the groups. Multivariate analysis demonstrated fusions involving the cervicothoracic junction and those involving 5 or more levels significantly affected alignment parameters. There were 27 complications requiring reoperation (14%) with no significant differences among the groups stratified by BMI (p = 0.386).

CONCLUSIONS

Overweight patients (BMI>25) with CSM undergoing PCF had a greater increase in SVA than normal weight patients while reoperation rates were similar. In addition, preoperative CL increased with increasing BMI, although this trend was not Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation significant and there was not found to be a significant difference between the change in CL from baseline to post-fusion between BMI cohorts. This study further highlights the importance of considering BMI when attempting to optimize sagittal alignment in patients undergoing PCF.

Biomechanical Evaluation of Different Surgical Approaches for the Treatment of Adjacent Segment Diseases After Primary Anterior Cervical Discectomy and Fusion: A Finite Element Analysis

Symptomatic adjacent segment disease (ASD) is a common challenge after anterior cervical discectomy and fusion (ACDF). The objective of this study was to compare the biomechanical effects of a second ACDF and laminoplasty for the treatment of ASD after primary ACDF. We developed a finite element (FE) model of the C2-T1 based on computed tomography images. The FE models of revision surgeries of ACDF and laminoplasty were simulated to treat one-level and two-level ASD after primary ACDF. The range of motion (ROM) and intradiscal pressure (IDP) of the adjacent segments, and stress in the cord were analyzed to investigate the biomechanical effects of the second ACDF and laminoplasty. The results indicated that revision surgery of one-level ACDF increased the ROM and IDP at the C2–C3 segment, whereas two-level ACDF significantly increased the ROM and IDP at the C2–C3 and C7-T1 segments. Furthermore, no significant changes in the ROM and IDP of the laminoplasty models were observed. The stress in the cord of the re-laminoplasty model decreased to some extent, which was higher than that of the re-ACDF model. In conclusion, both ACDF and laminoplasty can relieve the high level of stress in the spinal cord caused by ASD after primary ACDF, whereas ACDF can achieve better decompression effect. Revision surgery of the superior ACDF or the superior and inferior ACDF after the primary ACDF increased the ROM and IDP at the adjacent segments, which may be the reason for the high incidence of recurrent ASD after second ACDF.

Does cervical facet degeneration impact surgical outcomes and sagittal balance in patients with radiculopathy?

Purpose

In our present study, we aimed to investigate (1) whether cervical facet degeneration (FD) affects the clinical functional scores of patients with cervical radiculopathy after single-segment anterior cervical discectomy fusion (ACDF) and (2) whether FD affects the sagittal parameters of the cervical spine.

Methods

A total of 120 enrolled patients who underwent single-segment ACDF for radiculopathy with more than 2 years of follow-up were classified into two groups based on whether the preoperative mean FD was greater than or less than the mean FD grading score: mild FD group (mean score ≤ 2, n = 102) or severe FD group (mean score > 2, n = 48). Sagittal alignment changes and clinical functional scores were compared between the 2 groups. The relevant factors for FD were identified using multivariate logistic regression.

Results

Age, duration of symptoms, disc height and interfacet distance were independently associated with preoperative FD (age: P < 0.001; duration of symptoms: P = 0.020; disc height: P < 0.001; interfacet distance: P = 0.045). Compared with the mild FD group, the preoperative VAS (neck pain) score and NDI of the severe FD group were also higher, and the improvement of neck symptoms was better during the follow-up period. However, all clinical scores and radiographic parameters showed no significant differences during the 2-year follow-up. Additionally, no significant differences in the sagittal parameter changes were presented.

Conclusion

Patients with severe FD tended to experience more severe neck pain before surgery and greater improvement of neck symptoms at the follow-up visit. However, 2-year clinical efficacy and sagittal alignment after ACDF may not be markedly affected by preoperative FD severity. ACDF is considered to be a good choice for patients with radiculopathy, especially for patients with severe FD.

Assessment of spino cranial angle of cervical spine sagittal balance system after multi-level anterior cervical discectomy and fusion

Background

To analyze the impact of spino cranial angle (SCA) on alteration of cervical alignment after multi-level anterior cervical discectomy fusion (ACDF) and explore the relationship between SCA and health-related quality of life (HRQOL) scores.

Material and methods

In total, 49 patients following multi-level ACDF for multi-level cervical spondylotic myelopathy (MCSM) with more than 2 years follow-up period were enrolled. Radiographic data including SCA were measured. Receiver operating characteristics (ROC) curve analysis was applied to confirm the optimal cut-off values of SCA for predicting sagittal balance. Patients were divided into two groups on the basis of the cut-off value of preoperative SCA. Correlation coefficients were analyzed between SCA and HRQOL scores.

Results

Optimal cut-off values for predicting sagittal balance was SCA of 88.6°. Patients with higher SCA, no matter preoperatively, postoperatively and at follow-up, got lower T1-Slope (T1s), C2–C7 lordosis angle (CA) and higher △SCA (pre vs post: p = 0.036, pre vs F/U: p = 0.022). Simultaneously, pre-SCA, post-SCA, and F/U-SCA in the high SCA group were positively correlated with the pre-NDI, post-NDI, and F/U-NDI scores respectively (pre: p < 0.001, post: p = 0.015, F/U: p = 0.003). However, no correlation was performed in the low SCA group.

Conclusion

An excessive SCA can be considered to cause poorer clinical outcomes at preoperative and better correction after surgery. The SCA could be used as a new reference value to determine sagittal balance parameters of the cervical spine and to assess the quality of life.

Results of Four-Level Anterior Cervical Discectomy and Fusion Using Stand-Alone Interbody Titanium Cages

Study Design

This is a retrospective study with a minimum follow-up of 2 years.

Purpose

The aim of this study is to assess the long-term outcomes after performing the four-level anterior cervical discectomy and fusion (ACDF) in the treatment of degenerative cervical spine disease using stand-alone titanium cages.

Overview of Literature

Over the last decades, a rapid increase in the use of stand-alone cages for ACDF has been observed. However, research on their application in the treatment of four-level diseases is insufficient.

Methods

In this study, 130 patients presenting with symptomatic cervical spondylosis who underwent four-level ACDF using stand-alone cages in our institution between 2008 and 2016 were assessed. Fifty-two patients were women and 78 men with a mean age of 60.5 years. Their clinical and radiological outcomes were assessed. The results of the Neck Disability Index (NDI) and Visual Analog Scale as well as bony fusion were evaluated, and the revisions were analyzed. All of the patients underwent the four-level microscopic ACDF using the same titanium rectangular cage.

Results

The mean follow-up was 47±11.4 months. A fusion of all four levels was achieved in 80.72% of the patients. In 25 patients (19.23%), an incomplete bony bridging was observed in at least one fusion level at the final follow-up. However, only two patients (1.5%) were symptomatic and underwent revision. The mean NDI improved significantly from 39.4±9.3 at presentation to 8.3±6.6 at the final follow-up. Cervical lordosis improved significantly from a mean of 5.5° preoperatively to a mean of 15° postoperatively. Cage sinking and loss of segment height during healing had a mean of 3 mm.

Conclusions

Overall, the application of four-level ACDF using titanium cages in a stand-alone technique has been proven to be a safe and effective treatment method for degenerative disease. In a large cohort, a high rate of good long-term clinical and radiological results was achieved.

Determining the Difference in Clinical and Radiologic Outcomes Between Expandable and Nonexpandable Titanium Cages in Cervical Fusion Procedures: A Systematic Review and Meta-Analysis

BACKGROUND

Expandable cages have been increasingly used in cervical and lumbar reconstructions; however, there is a paucity in the literature on how they compare with traditional nonexpandable cages in the cervical spine. We present a systematic review and meta-analysis, comparing the clinical and radiologic outcomes of expandable versus nonexpandable corpectomy cage use in the cervical spine.

METHODS

A database search identified studies detailing the outcomes of expandable and nonexpandable titanium cage use in the cervical spine. These studies were screened using the PRISMA protocol. Fixed-effects and random-effects models were used with a 95% confidence interval. Two analyses were carried out for each outcome: one including all studies and the other including only studies reporting on exclusively 1-level and 2-level cases.

RESULTS

Forty-one studies were included. The mean change in segmental lordosis was significantly greater in expandable cages (all, 6.72 vs. 3.69°, P < 0.001; 1-level and 2-level, 6.81° vs. 4.31°, P < 0.001). The mean change in cervical lordosis was also significantly greater in expandable cages (all, 5.71° vs. 3.11°, P = 0.027; 1-level and 2-level, 5.71° vs. 2.07°, P = 0.002). No significant difference was found between the complication rates (all, P = 0.43; 1-level and 2-level, P = 0.94); however, the proportion of revisions was significantly greater in expandable cages (all, 0.06 vs. 0.02, P = 0.03; 1-level and 2-level, 0.08 vs. 0.01, P = 0.017).

CONCLUSIONS

The use of expandable cages may carry a modest improvement in radiologic outcomes compared with nonexpandable cages in the cervical spine; however, they may also lead to a higher rate of revisions based on our analyses.

Influence of SCA on clinical outcomes and cervical alignment after laminoplasty in patients with multilevel cervical spondylotic myelopathy

Background

To study the impact of changes in spino-cranial angle (SCA) on sagittal alignment and to investigate the relationship between SCA and Neck Disability Index (NDI) scores after laminoplasty (LP)

Material and methods

In total, 72 patients with multilevel cervical spondylotic myelopathy (MCSM) after laminoplasty (LP) were retrospectively enrolled. Based on the optimal cut-off values of preoperative SCA, patients were classified into low SCA and high SCA groups. Radiographic data were measured, including spino-cranial angle (SCA), T1-slope (T1s), C2–7 lordosis (CA), T1s minus CA (T1sCA), and C2–7 sagittal vertical axis (cSVA). JOA and NDI scores were both applied to assess postoperative and follow-up clinical efficacy. Pearson correlation coefficient and linear regression analysis were respectively calculated between radiographic data and between SCA and NDI.

Results

The preoperative SCA was significantly correlated with T1s (r = − 0.795), CA (r = − 0.857), and cSVA (r = 0.915). A receiver operating characteristic (ROC) curve model predicted a threshold of SCA (value of 85.2°). At the follow-up period, patients with lower SCA had a higher T1s and CA and a lower cSVA, simultaneously accompanied by greater △T1s, △CA, and △cSVA. The linear regression model demonstrated that SCA in the higher group was positively correlated with NDI, and patients with higher SCA had worse NDI scores (pre: p < 0.001; post: p < 0.001; F/U: p = 0.003) and greater changes of NDI (post: p < 0.010; F/U: p = 0.002).

Conclusion

SCA may be a good predictor of evaluating sagittal balance and planning surgery. Changes in sagittal alignment in the low SCA group were affected more easily, and a higher SCA was associated with worse quality of life. Laminoplasty could be a good choice for patients with lower SCA.

Vertebral Body Replacement With an Anchored Expandable Titanium Cage in the Cervical Spine: A Clinical and Radiological Evaluation

BACKGROUND

Expandable cervical cages have been used successfully to reconstruct the anterior spinal column.

OBJECTIVE

To perform clinical and radiological evaluation of vertebral body replacement with an anchored expandable titanium cage in the cervical spine after single-level and 2-level corpectomies.

METHODS

Between 2011 and 2017, 40 patients underwent a single-level (N = 32) or 2-level (N = 8) anterior corpectomy and fusion using an anchored expandable vertebral body replacement cage. Clinical and radiological data at admission, postoperatively, and at 3- and 12-mo follow-up were retrospectively analyzed. Clinical assessment was performed via standardized neurological evaluation, Odom score, and McCormick classification. Radiological assessment was performed via evaluation of sagittal profile, postoperative position, fusion, and subsidence rates.

RESULTS

Mean last follow-up was 14.8 ± 7 mo. Overall clinical and myelopathy-related improvements were shown directly after operation and at last follow-up. A stable centralized positioning of cages was achieved in 37 patients (93%). A mild ventral (>1.5 mm) malplacement was noted in 3 patients (7%) without clinical consequences. Sagittal alignment and preoperative cervical kyphosis improved significantly (7.8° gain of lordosis) and remained stable. Mean preoperative height of operated segments increased by 10 mm postoperatively and remained stable. Fusion rate in non-neoplastic patients and subsidence rate at last follow-up comprised 87.5% and 17.8%. With exception of 1 patient suffering from severe osteoporosis and cage subsidence, no patient needed additional secondary stabilization.

CONCLUSION

Anterior corpectomy and fusion by an expandable anchored titanium cage with anchor screws without additional instrumentation resulted in overall clinical improvement and radiological anterior column support, achieving significant and reliable restoration of the physiological sagittal cervical profile.

A prospective randomized cohort study on 3D-printed artificial vertebral body in single-level anterior cervical corpectomy for cervical spondylotic myelopathy

Background

This was a prospective randomized cohort study aiming at examining the safety and efficacy of artificial vertebral body (AVB) fabricated by electron beam melting (EBM) in comparison to conventional titanium mesh cage (TMC) used in single-level anterior cervical corpectomy and fusion (SL-ACCF).

Methods

Forty patients with cervical spondylotic myelopathy (CSM) underwent SL-ACCF using either the EBM-AVB or the TMC. Patients were evaluated for their demographics, radiological characteristics, neurologic function [using the Japanese Orthopaedic Association (JOA) scale], and health-related quality-of-life (HRQoL) aspects [using the Short Form 36 (SF-36)] before and after the surgery and comparison was made between the two groups both at baseline and the last follow-up. The Student t-text, paired-sample t-text, and Fisher's exact test were used when appropriate to detect any statistical significance at the level of α=0.05.

Results

Post-operative recovery was uneventful for all patients and no revision surgery was required. There were no significant differences between the EBM-AVB group and the TMC group at baseline. Patients in both groups demonstrated significant improvement in cervical alignment, JOA score, and SF-36 score after the surgery. Six months post-operatively, patients in the EBM-AVB group were found to have significantly less loss of fusion height and lower incidence for severe implant subsidence compared with the TMC group. Patients in the two groups were comparable at the last follow-up regarding their rate of fusion, cervical alignment, JOA recovery rate, SF-36 score, and by Odom's criteria.

Conclusions

For CSM patients undergoing SL-ACCF, the EBM-AVB group demonstrated comparable outcomes regarding patient cervical alignment, neurologic function, and HRQoL in comparison with the TMC group. Furthermore, the use of EBM-AVB was associated with decreased loss of the height of the fusion mass and a lower rate for severe implant subsidence.

Cervical Sagittal Alignment: Literature Review and Future Directions

Cervical alignment as a concept has come to the forefront for spine deformity research in the last decade. Studies on cervical sagittal alignment started from normative data, and expanded into correlation with global sagittal balance, prognosis of various conditions, outcomes of surgery, definition and classification of cervical deformity, and prediction of targets for ideal cervical reconstruction. Despite the recent robust research efforts, the definition of normal cervical sagittal alignment and cervical spine deformity continues to elude us. Further, many studies continue to view cervical alignment as a continuation of thoracolumbar deformity and do not take into account biomechanical features unique to the cervical spine that may influence cervical alignment, such as the importance of musculature connecting cranium-cervical-thoracic spine and upper extremities. In this article, we aim to summarize the relevant literature on cervical sagittal alignment, discuss key results, and list potential future direction for research using the '5W1H' framework; "WHO" are related?, "WHY" important?, "WHAT" to evaluate and "WHAT" is normal?, "HOW" to evaluate?, "WHEN" to apply sagittal balance?, and "WHERE" to go in the future?

The safety and efficacy of anterior versus posterior decompression surgery in degenerative cervical myelopathy: a prospective randomized trial

OBJECTIVE

The safety and efficacy of anterior and posterior decompression surgery in degenerative cervical myelopathy (DCM) have not been validated in any prospective randomized trial.

METHODS

In this first prospective randomized trial, the patients who had symptoms or signs of DCM were randomly assigned to undergo either anterior cervical discectomy and fusion or posterior laminectomy with or without fusion. The primary outcome measures were the change in the visual analog scale (VAS) score, Neck Disability Index (NDI), and Nurick myelopathy grade 1 year after surgery. The secondary outcome measures were intraoperative and postoperative complications, hospital stay, and Odom's criteria. The follow-up period was at least 1 year.

RESULTS

A total of 68 patients (mean age 53 ± 8.3 years, 72.3% men) underwent prospective randomization. There was a significantly better outcome in the NDI and VAS scores in the anterior group at 1 year (p < 0.05). Nurick myelopathy grading showed nonsignificant improvement using the posterior approach group (p = 0.79). The mean operative duration was significantly longer in the anterior group (p < 0.001). No significant difference in postoperative complications was found, except postoperative dysphagia was significantly higher in the anterior group (p < 0.05). There was no significant difference in postoperative patient satisfaction (Odom's criteria) (p = 0.52). The mean hospital stay was significantly longer in the posterior group (p < 0.001).

CONCLUSIONS

Among patients with multilevel DCM, the anterior approach was significantly better regarding postoperative pain, NDI, and hospital stay, while the posterior approach was significantly better in terms of postoperative dysphagia and operative duration.

Predictors of poor outcome in cervical spondylotic myelopathy patients underwent anterior hybrid approach: focusing on change of local kyphosis

Objective

This study was a retrospective multivariable analysis for risk factors of poor outcome in patients who underwent anterior hybrid approach, and discussed the causes of worsening of postoperative local alignment.

Methods

A total of 86 patients with progressive spinal cord compression and local kyphosis underwent an anterior hybrid approach (ACDF+ACCF), between June 2011 and June 2017. We evaluated clinical outcome by the Japanese Orthopaedic Association (JOA) score and recovery rate. Patients were divided into two groups according to the worsening and improving of postoperative local alignment. Multivariate logistic regression analysis was applied to the evaluation of risk factors. Mann-Whitney U test, independent t test, and chi-squared test were performed for the comparison of local kyphosis between postoperative and last follow-up.

Results

There were twenty patients who had a recovery rate of less than 50%. Advance age, longer duration of symptoms, bigger T1 slope angle, and lower change of local kyphosis angle were significantly associated with a poor clinical outcome by multivariate logistic regression analysis. The cause of worsening of postoperative local alignment had T1 slope, C2–7 sagittal vertical axis (SVA), adjacent segment degeneration (ASD), and implant subsidence.

Conclusions

The change of local kyphosis was a predictor of clinical outcome after the hybrid approach. Furthermore, postoperative ASD, implant subsidence, T1 slope, and C2–7 Cobb were associated with recurrence of postoperative cervical kyphosis.

Comparison between repeat anterior and posterior decompression and fusion in the treatment of two-level symptomatic adjacent segment disease after anterior cervical arthrodesis

BACKGROUND

Two-level symptomatic adjacent segment disease (ASD) is rarely reported, but remains a challenge after anterior cervical arthrodesis. The purpose of this study was to compare the clinical and radiological outcomes of repeat anterior and posterior decompression and fusion procedures for two-level symptomatic ASD.

METHODS

Thirty-two patients with two-level symptomatic ASD were retrospectively reviewed and underwent repeat anterior cervical discectomy and fusion (ACDF) or posterior decompression and fusion (PDF). Clinical outcomes (JOA, NDI, and VAS scores), perioperative parameters (blood loss, operation time, and length of hospital stay), radiological parameters (cervical lordosis and ROM), and complications were compared.

RESULTS

Eighteen patients underwent ACDF, and 14 patients underwent PDF. Patients who underwent PDF were older, more frequently presented with myelopathic deficits, and were fused at more levels. Patients who underwent ACDF experienced significantly shorter surgery time (p < 0.001), lower blood loss (p < 0.001), and reduced hospital stay (p = 0.002). Both groups exhibited significant increases in JOA scores and decreases in NDI and both neck pain and arm pain VAS scores (p < 0.05), but patients who underwent PDF had significantly higher NDI scores (p = 0.012), neck pain VAS scores (p = 0.019), loss of cervical lordosis (p < 0.001), and loss of ROM (p = 0.001). Three patients developed dysphagia in the ACDF group, and two patients had C5 root palsy and one had hematoma in the PDF group. Recurrent ASD after the second operation occurred in two patients in the ACDF group but no patients in the PDF group.

CONCLUSIONS

For patients with two-level symptomatic ASD, both anterior and posterior decompression and fusion were effective for improving the neurological function. For patients with radicular symptoms, ACDF had less surgical trauma, better restoration of lordosis, and less postoperative neck pain, but higher chance of recurrent ASD. PDF was an effective surgical option for older patients with myelopathy developing in adjacent segments.

Impact of the Inclusion of C2 in Posterior Cervical Fusions for Cervical Myelopathy on Sagittal Cervical Alignment

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine the impact of including C2 in posterior fusions on radiographic parameters of cervical alignment in cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

Despite the use of posterior instrumentation and arthrodesis after cervical laminectomy, loss of lordosis and the development of kyphosis are prevalent. Inadequate cervical lordosis and other measures of sagittal cervical alignment have been shown to correlate with disability, general health scores, and severity of myelopathy. The role of C2 in the posterior tension band, which maintains sagittal alignment, differs from the subaxial spine, as it is the insertion point for erector spinae muscles that play a critical role in maintaining posture.

PATIENTS AND METHODS

This study compares the radiographic outcomes of sagittal balance between 2 cohorts of patients who underwent posterior cervical decompression and fusion for cervical myelopathy over a 12-year period at a single institution. Demographic and surgical characteristics were collected using the electronic medical record of patients undergoing posterior cervical fusions (PCF) which included the axis [axial fusion (AF)] and those that were subaxial fusions (SAF). Radiographic measurements included preopertaive and postoperative C2-C7 lordosis (CL), C2-C7 sagittal vertical axis (SVA), and T1 slope (T1S).

RESULTS

After review of the electronic medical records, 229 patients were identified as having PCF and decompression for treatment of myelopathy. One hundred sixty-seven patients had AF, whereas 62 had SAF. PCF resulted in loss of CL in both cohorts. Although there was no statistical difference in postoperative CL, there was a significant increase in SVA (P<0.001) and T1S (P<0.001) with AF.

CONCLUSIONS

PCF often result in loss of lordosis. When compared with SAF, inclusion of C2 into the fusion construct may result in worsened sagittal balance, increasing the SVA and T1S.

Follow-up of a new titaniumcoated polyetheretherketone cage for the cervical spine

Poly-ether-ether-ketone (PEEK) cages have lower modulus of elasticity when compared with Titanium (TTN) cages. This suggests that PEEK-cages could show a lower rate of subsidence after anterior cervical discectomy-fusion (ACDF) and might lead to a lower loss of correction. We investigated the one to five year-results of standalone PEEK-TTN-porous coated cages in a patient cohort from 2014 to 2017. The patients underwent single-level ACDF for disc herniation and degenerative discopathy. Clinical and radiological outcome were assessed in 50 eligible patients after a mean of 27 months. Results: Solid arthrodesis was found in 84%. Neck disability index (NDI), and visual analogue scale (VAS) of neck and arm show comparable results to the literature. Conclusions: Clinical and radiological outcomes of ACDF with PEEK-body-cages with a porous coated surface show good bony integration. The modulus of elasticity, design, shape, size, cage surface architecture, as well as bone density, endplate preparation, radical microdiscectomy and distraction during surgery should be considered as important factors influencing the clinical results. One main advantage, over titanium cages, is the absence of MRI artifacts, allowing an excellent postoperative follow-up.

Sagittal alignment of the cervical spine: do we know enough for successful surgery?

Over the past decade, there has been growing interest in the sagittal alignment of the cervical spine and its correlation to clinical outcomes. It is now known that cervical lordosis is not universally physiological and should not be pursued in all patients undergoing surgery. Rather, it is increasingly understood that it is how these angular parameters (lordosis or kyphosis) interact with translational parameters that is reflective of overall cervical spine and whole spine balance, which in turn impacts patient outcomes. This review synthesises currently available evidence relating to the sagittal alignment of the cervical spine. Radiographic assessment of the cervical spine including horizontal gaze is discussed and alignment in physiological and pathological states analysed. The interdependence of spinal segments is reviewed, with cervical alignment correction influencing the adjacent thoracic spine, and similarly lumbar lordosis (LL) and global balance correction changing cervical spine alignment. Cervical kyphosis with associated cervical sagittal imbalance is known to lead to poorer post-operative outcomes, and this dichotomy in outcomes has not been shown to improve even with alignment correction. Further work is required to uncover the extent to which cervical spine alignment correction should be attempted toward improved patient outcomes, in order to plan and deliver patient-specific surgical realignment targets.

A National Snapshot Detailing the Impact of Parkinson's Disease on the Cost and Outcome Profiles of Fusion Procedures for Cervical Myelopathy

BACKGROUND

Studies suggest a higher prevalence of cervical deformities in Parkinson's Disease (PD) patients who predispose to cervical myelopathy (CM). Despite the profound effect of CM on function and quality of life, no study has assessed the influence of PD on costs and outcomes of fusion procedures for CM.

OBJECTIVE

To conduct the first national-level study that provides a snapshot of the current outcome and cost profiles for different fusion procedures for CM in PD and non-PD populations.

METHODS

Patients with or without PD who underwent cervical decompression and fusion anteriorly (ACDF), posteriorly (PCDF), or both (Frontback), for CM were identified from the 2013 to 2014 National Inpatient Sample using International Classification of Disease codes.

RESULTS

A total of 75 870 CM patients were identified, with 535 patients (0.71%) also having PD. Although no difference existed between in-hospital mortality rates, overall complication rates were higher in PD patients (38.32% vs 22.05%; P < .001). PD patients had higher odds of pulmonary (P = .002), circulatory (P = .020), and hematological complications (P = .035). Following ACDFs, PD patients had higher odds of complications (P = .035), extended hospitalization (P = .026), greater total charges (P = .003), and nonhome discharge (P = .006). Although PCDFs and Frontbacks produced higher overall complication rates for both populations than ACDFs, PD status did not affect complication odds for these procedures.

CONCLUSION

PD may increase risk for certain adverse outcomes depending on procedure type. This study provides data with implications in healthcare delivery, policy, and research regarding a patient population that will grow as our population ages and justifies further investigation in future prospective studies.

0.5- to 1-Fold Intervertebral Distraction Is a Protective Factor for Adjacent Segment Degeneration in Single-level Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

This study aimed to compare the clinical and radiological outcomes of different degrees of distraction in anterior cervical discectomy and fusion (ACDF) and evaluate the risk factors for adjacent segment degeneration (ASD).

SUMMARY OF BACKGROUND DATA

ASD is a common complication following ACDF. Inadequate distraction of the intervertebral space during surgery is associated with ASD; however, there is still an ongoing debate regarding what degree of distraction is appropriate.

METHODS

This retrospective study enrolled 130 patients who underwent single-level ACDF for cervical degenerative disc disease and were followed up at least 2 years. The patients were divided into the following three groups according to the degree of distraction (≤0.5, 0.5-1, ≥1): insufficient distraction group (ID group), appropriate distraction group (AD group), and excessive distraction group (ED group). The clinical outcomes and radiological parameters were evaluated before and after operation and at the last follow-up. Risk factors for ASD were identified through logistic regression analysis.

RESULTS

A significant difference was found in the Visual Analog Scale values between the AD group and ED group at the final follow-up. Moreover, the highest upper segmental disc height (DH), highest lower segmental DH, and lowest incidence of ASD were found in the AD group among the three groups at last follow up. Logistic regression analysis revealed that segmental kyphosis (odds ratio = 2.821, P = 0.020) was a risk factor for the occurrence of ASD and 0.5- to 1-fold distraction (odds ratio = 0.350, P = 0.025) was a protective factor.

CONCLUSION

Good clinical and radiological outcomes were achieved in ACDF with 0.5- to 1-fold distraction. Segmental kyphosis is a risk factor for ASD in ACDF, whereas 0.5- to 1-fold distraction is a protective factor of ASD.

LEVEL OF EVIDENCE

4.

Is Cervical Sagittal Balance Related to the Progression of Patients with Cervical Spondylotic Myelopathy?

OBJECTIVE

To examine the preoperative patients with cervical spondylotic myelopathy (CSM): (1) whether cervical sagittal parameters are related to the progress of patients with CSM, and (2) whether cervical sagittal parameters can predict disease progression or prognosis in patients with CSM.

METHODS

From 2015 to 2018, 126 preoperative patients with CSM were enrolled. The inclusion criteria included cervical lateral radiograph, flexion (F), extension (E), and some clinical function scores (visual analog score, modified Japanese Orthopedic Association, Neck Disability Index [NDI], the Medical Outcomes Study 36-Item Short-Form Health Survey, Patient Health Questionnaire-9). Health Transition was used to evaluate the patient's disease progress. The following radiographic parameters were measured: (1) C0-C2 lordosis, (2) C2-C7 lordosis, (3) C7 slope, (4) T1 slope, (5) C2-C7 sagittal vertical axis, (6) cervical tilt, (7) cranial tilt, (8) cervical curvature index (CCI), and (9) CCI change constant (CCI-CC). Of the 126 patients, 101 chose surgical treatment. We followed up for 1 year and grouped the patients with the C2-C7 Cobb angle (F) > 29°. We compared the prognosis of the surgical group and the disease progression of the nonsurgical group.

RESULTS

In preoperative patients with CSM, modified Japanese Orthopedic Association was positively correlated with cervical tilt (E), cervical tilt (range of motion), and CCI (range of motion). The larger CCI-CC is the only independent risk factor for the NDI increase. High C2-7F, low cervical tilt, and low cervical tilt (F) values are independent predictors of high Health Transition scores. Whether in the surgical group or the nonsurgical group, the recovery of patients with C2-7F > 29° was better than that of patients with C2-7F ≤ 29°.

CONCLUSION

In preoperative patients with CSM, the larger CCI-CC is the only independent risk factor for the NDI increase. When the patient has a C2-C7 Cobb angle (F) > 29°, the patient's condition progresses slowly.

Effect of microscopically assisted decompression with micro-hook scalpel in the surgical treatment of ossification of the posterior longitudinal ligament

Objective

This study was performed to investigate the effect of microscopically assisted decompression using a micro-hook scalpel on ossification of the posterior longitudinal ligament (OPLL).

Methods

Sixty-one patients with OPLL were divided into Group A (posterior surgery with laminectomy of the responsible segment and lateral mass screw fixation) and Group B (anterior cervical corpectomy with intervertebral titanium cage fusion). Neurological function was assessed by the Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score, and recovery rate. The fixation status and the result of spinal canal decompression were radiographically assessed.

Results

In Groups A and B, the JOA score was significantly higher and the VAS score was significantly lower at 1 week postoperatively and at the final follow-up than during the preoperative period. The mean recovery rate in Group A and B was 59.92% ± 13.46% and 62.28% ± 14.00%, respectively. Postoperative radiographs showed good positioning and no damage to the internal fixation materials. The spinal canal was also fully decompressed.

Conclusions

Microscopically assisted decompression with a micro-hook scalpel in both anterior and posterior surgeries achieved good clinical effects in patients with OPLL.

Cervical Laminectomy With or Without Lateral Mass Instrumentation: A Comparison of Outcomes

STUDY DESIGN

Narrative review.

BACKGROUND

Cervical decompressive laminectomy is a common posterior approach for addressing multilevel cervical spondylotic myelopathy. However, there is a concern that cervical laminectomy can lead to kyphotic deformity with subsequent neurological decline. In this context, cervical laminectomy with fusion using lateral mass instrumentation has become increasingly utilized with the aim of reducing the risk of developing postoperative kyphotic deformity, which is thought to predispose to poorer neurological outcomes in the long term.

OBJECTIVE

To compare the evidence for stand-alone cervical laminectomy with laminectomy with posterior fusion in terms of clinical outcomes and the incidence of adverse events, particularly the development of postoperative cervical kyphosis.

MATERIAL AND METHODS

Initial Medline search using MeSH terms yielded 226 articles, 23 of which were selected. An additional PubMed search and the reference list of individual papers were utilized to identify the remaining papers of relevance.

RESULTS

Cervical laminectomy both with and without fusion offers effective decompression for symptomatic multilevel cervical spondylotic myelopathy. The incidence of postlaminectomy kyphosis is lower following posterior fusion; however, there seems to be no clinical-radiologic correlation given that patients who develop postoperative kyphosis often do not progress to clinical myelopathy. Furthermore, there are specific additional risks of posterior instrumentation that need to be considered.

CONCLUSION

In carefully selected patients with normal preoperative cervical sagittal alignment, stand-alone cervical laminectomy may offer acceptably low rates of postoperative kyphosis. In patients with preoperative loss of cervical lordosis and/or kyphosis, posterior fusion is recommended to reduce the risk of progression to postoperative kyphotic deformity, bearing in mind that radiologic evidence of kyphosis may not necessarily correlate with poorer clinical outcomes. Furthermore, the specific risks associated with posterior fusion (instrumentation failure, pseudarthrosis, infection, C5 nerve root palsy, and vertebral artery injury) need to be considered and weighed up against potential benefits.

Anterior versus posterior approach for the therapy of multilevel cervical spondylotic myelopathy: a meta-analysis and systematic review

BACKGROUND

The goal of this meta-analysis is to explore the overall efficacy as well as the safety of anterior versus posterior approach for the therapy of patients with multilevel cervical spondylotic myelopathy based on qualified studies.

METHODS

Three electronic databases, PubMed, Cochrane, Embase were searched updated to January 2018 to identify all relevant and qualified studies using the index words. The qualified studies were including prospective or retrospective comparative studies. Relative risk (RR) and mean difference (MD) along with 95% confidence interval (95% CI) were used to analyze the main outcomes.

RESULTS

In this meta-analysis, there were a total of 24 studies with 959 patients in the anterior approach group and 1072 patients in the posterior approach group. The final results showed, in comparison of the posterior approach group, the anterior approach group significantly increased the JOA score (SMD: 0.36, 95% CI 0.10-0.62), the operation time (WMD: 49.87, 95% CI 17.67-82.08), and the neurological recovery rate (WMD: 10.55, 95% CI 3.99-17.11) with higher complication rate (RR: 1.53, 95% CI 1.24-1.89). Besides, there was no significant difference of the blood loss (SMD: - 0.40, 95% CI - 1.12 to 0.32) and ROM (SMD: - 0.28, 95% CI - 0.78 to - 0.22) between posterior approach group and anterior approach group.

CONCLUSIONS

Studies found a significant increase of JOA score as well as neurological recovery rate by the anterior approach treatment when compared with posterior approach treatment. However, increased operation time and complications could also occur through the anterior approach treatment. More high-quality randomized controlled trials with larger sample size, multi-centric and longer follow-ups are needed to support our current conclusions.

Anterior and Posterior Approaches for Cervical Myelopathy: Clinical and Radiographic Outcomes

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to identify advantages and disadvantages of the anterior and posterior approaches in the treatment of cervical stenosis and myelopathy.

SUMMARY OF BACKGROUND DATA

Both anterior and posterior surgical approaches for cervical stenosis and myelopathy have been shown to result in improvement in health-related outcomes. Despite the evidence, controversy remains regarding the best approach to achieve decompression and correct deformity.

METHODS

We retrospectively reviewed patients with cervical stenosis and myelopathy who had undergone anterior cervical fusion and instrumentation (n = 38) or posterior cervical laminectomy and instrumentation (n = 51) with at least 6 months of follow-up. Plain radiographs, magnetic resonance imaging, and computed tomography scans, as well as health-related outcomes, including Visual Analog Scale for neck pain, Japanese Orthopedic Association score for myelopathy, Neck Disability Index, and Short Form-36 Health Survey, were collated before surgery and at follow-up (median 12.0 and 12.1 months for anterior and posterior group, respectively).

RESULTS

Both anterior and posterior approaches were associated with significant improvements in all studied quality of life parameters with the exception of general health in the anterior group and energy and fatigue in the posterior group. In the anterior group, follow-up assessment revealed a significant increase in C2-7 lordosis. Both approaches were accompanied by significant increases in C2-7 sagittal balance [sagittal vertical axis (SVA)]. There were two complications in the anterior group and nine complications in the posterior group; the incidence of complications between the two groups was not significantly different.

CONCLUSION

When the benefits of one approach over the other are not self-evident, the anterior approach is recommended, as it was associated with a shorter hospital stay and more successful restoration of cervical lordosis than posterior surgery.

LEVEL OF EVIDENCE

3.

The effect of dural release on extended laminoplasty for the treatment of multi-level cervical myelopathy

Objective

The effects of dural release on extended laminoplasty for the treatment of multi-level cervical myelopathy were explored and discussed.

Method

Patients, who underwent extended laminoplasty combined with dural release for the treatment of multi-level cervical myelopathy (35 cases, group A), were compared with patients who underwent simple extended laminoplasty (38 cases, group B). The JOA score, improvement rate, VAS score, distance of retroposition of the spinal cord, cervical lordosis were compared between the two groups.

Results

Dural laceration occurred to five patients during surgery, three in group A and two in group B; cerebrospinal fluid leakage occurred to five patients, three in group A and two in group B. All patients were followed up for 10 to 48 months (mean 20.3 months). JOA scores and VAS scores in the last follow up period were significantly improved in the two groups than preoperative scores (p < 0.05). The improvement rate and JOA scores in group A were significantly higher than group B, while VAS scores in group A were significantly lower than group B (p < 0.05). There were no significant differences in cervical lordosis in the two groups in the last follow up (p > 0.05), and the distance of retroposition of the spinal cord in group A was higher than B (p < 0.05). No shut-up of the ‘door’ of vertebral lamina occurred in the period of follow-up.

Conclusion

Dural release on extended laminoplasty can achieve retroposition of the spinal cord for multi-level cervical myelopathy, which is more effective than simple extended laminoplasty.

Preoperative Modic changes are related to axial symptoms after anterior cervical discectomy and fusion

Background

The objective of this study was to compare the clinical and radiological outcomes between patients with or without axial symptoms (AS) and investigate the risk factors associated with AS by multivariate regression analysis in anterior cervical discectomy and fusion (ACDF).

Materials and methods

The records of 117 patients who underwent ACDF were reviewed for clinical and radiological outcomes. These outcomes were evaluated before and after surgery and at the last follow-up. Preoperative Modic changes (MCs) adjacent to the treated disc were identified. Risk factors for AS were detected through logistic regression analysis.

Results

The patients were divided into two groups: one with AS (AS group, n=35) and the other without (NAS group, n=82). Visual Analog Scale values after the operation (P=0.013) and at final follow-up (P<0.001) and preoperative segmental angle (P=0.031) were significantly different between the two groups. There were no significant differences with respect to other clinical and radiographic outcomes between the two groups (P>0.05). Logistic regression analysis revealed that preoperative segmental kyphosis (OR =2.912, P=0.035) and MCs (odds ratio =3.268, P=0.015) were the risk factors for the occurrence of AS.

Conclusion

AS do not correlate with recovery of neural function in patients treated by ACDF. In addition, preoperative segmental kyphosis and MCs at the fusion segment were found to affect the incidence of AS after ACDF.

Cervical Sagittal Range of Motion as a Predictor of Symptom Severity in Cervical Spondylotic Myelopathy

STUDY DESIGN

A retrospective review of radiographic data and functional outcomes.

OBJECTIVE

The aim of this study was to evaluate whether myelopathy symptom severity upon presentation corresponds to sagittal plane alignment or nonmyelopathy symptoms, such as pain, in patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Cervical sagittal balance is an important parameter in the outcome of surgical reconstruction. However, the effect of sagittal alignment on symptom severity in patients who have not undergone spine surgery is not well defined.

METHODS

A consecutive series of CSM patients was identified at an academic institution. Preoperative radiographs were analyzed for sagittal vertical axis (C2SVA), C7 slope (C7S), C2-C7 angle in neutral (C27N), flexion (C27F), and extension (C27E), and range of motion (C27ROM). Neutral alignment was categorized as lordotic, kyphotic, or sigmoid/straight. Outcomes collected were SF-12, neck disability index, arm pain, neck pain, and modified JOA (mJOA). Pearson coefficients determined correlations between radiographic and outcome parameters. Multivariate regression evaluated predictive factors of mJOA.

RESULTS

Radiographic parameters did not correlate with pain. Increasing age, smaller C27ROM, and smaller flexion angles correlated to lower (more severe) baseline mJOA scores. ROM (and not static alignment) was the only significant predictor of mJOA in the multivariate regression. Despite significant radiographic differences between lordotic, kyphotic, and sigmoid/straight alignment groups, myelopathy severity did not differ between these groups.

CONCLUSION

Static, neutral alignment, including SVA and lordosis, did not correlate with myelopathy or pain symptoms. Greater C27ROM and increased maximal flexion corresponded to milder myelopathy symptoms, suggesting that patients with myelopathy may compensate for cervical stenosis with hyperflexion, similar to that which is observed in the lumbar spine. In a CSM patient population, dynamic motion and compensatory deformities may play a more significant role in myelopathy symptom severity than what can be discerned from standard, neutral position radiographs.

LEVEL OF EVIDENCE

3.

Cervical sagittal balance parameters after single-level anterior cervical discectomy and fusion: Correlations with clinical and functional outcomes

Background:

Normal sagittal cervical alignment has been associated with improved outcome after anterior cervical discectomy and fusion (ACDF).

Objective:

The aim of this study is to identify alterations of cervical sagittal balance parameters after single-level ACDF and assess correlations with postoperative functionality.

Methods:

A retrospective chart review was performed between January 2010 and January 2014 to identify adult patients with no previous cervical spine surgery who underwent ACDF at any one level between C2 and C7 for the single-level degenerative disease. Tumor, infection, and trauma cases were excluded from the study. For the included cases, the following data were recorded preoperatively and 6 months–1 year after surgery: sagittal balance-marker measurements of the C1–C2 angle, C2–C7 angle, C7 slope, segmental angle at the operated level, and sagittal vertical axis (SVA) distance between C2 and C7, as well as the neck disability index and visual analog scale of pain.

Results:

The present study included 47 patients (average age: 51.2 years; range: 28–86 years). A moderate negative correlation between a smaller C2–C7 angle and the presence of right arm pain before treatment was found (P = 0.0281). Postoperatively, functionality scores significantly improved in all patients. C1–C2 angle increased with statistical significance (P = 0.0255). C2–C7 angle, segmental angle, C7 slope, and SVA C2–C7 distance did not change with statistical significance after surgery. C7 slope significantly correlated with overall cervical sagittal balance (P < 0.05).

Conclusions:

Single-level ACDF significantly increases upper cervical lordosis (C1–C2) without significantly changing lower cervical lordosis (C2–C7). The C7 slope is a significant marker of overall cervical sagittal alignment (P < 0.05).

Ossification of the Posterior Longitudinal Ligament in Cervical Spine: Prevalence, Management, and Prognosis

Ossification of the posterior longitudinal ligament (OPLL) in the cervical spine and related neurological complications are not uncommon in East Asian countries. The estimated prevalence of cervical OPLL-related hospitalization is 7.7 per 100,000 person-years in Taiwan, and higher incidence rates have been observed in elderly and male patients. Although cervical OPLL is frequently insidious, it can eventually cause myelopathy and predispose patients to spinal cord injury (SCI). There are multiple options for managing cervical OPLL, ranging from observation to many kinds of surgical procedures, including posterior laminoplasty, laminectomy with or without fusion, anterior corpectomy with or without instrumentation, and circumferential decompression and fusion. None of these surgical approaches is free of complications. However, to date, there is still a lack of consensus regarding the choice of the surgical approach and the timing of surgical intervention. Cervical SCI and related neurological disabilities are more likely to occur in OPLL patients, who should therefore be cautioned regarding the possibility of a subsequent SCI if treated without surgery. This article aimed to review the prevalence, management strategies, and prognosis of cervical OPLL.