Importance of Sagittal Alignment of the Cervical Spine in the Management of Degenerative Cervical Myelopathy

The Relationship Between Craniocervical Morphology and the Presence and Level of Cervical Facet Joint Degeneration

OBJECTIVE

To investigate the relationship between craniocervical morphology and the presence and level of cervical facet joint degeneration (FJD).

METHODS

A total of 108 consecutive female patients aged 45-55 years who had undergone neck + brain CT angiography were included in this retrospective sectional study. Only patients of a certain age and of the same gender were included in order to eliminate the differences that create a disposition to the development of spinal degeneration. The presence of facet joint (FJ) arthritis (grade ≥2 degeneration in at least one affected facet joint) and the grade of the facet joint degeneration for each patient were recorded. A total of 20 lengths and 3 angles of craniocervical morphology were measured. The differences between the individuals with and without FJ arthritis were investigated with the independent-sample t test, and the relationship between the FJD grade and craniocervical morphology was investigated using the Spearman correlation test.

RESULTS

Individuals with FJ arthritis were found to have longer Grabb-Oakes measurement, shorter FM AP length, lower ADI, lower EOP thickness, higher clivus length, higher crista gall-ATS distance, lower CCA angle, lower distance between the C1 vertebra lateral masses, and higher BAI than those without FJ arthritis (P ˂ 0.05). Besides, we found that the FJD grade increased as the Grabb-Oakes measurement increased, ADI distance decreased, FM AP length decreased, EOP thickness decreased, clivus length increased, basal angle increased, distance between the C1 vertebra lateral masses decreased, and BAI increased (P ˂ 0.05).

CONCLUSIONS

Differences in craniocervical morphology are statistically associated with degenerative processes that result in degenerative changes in the facet joint. Therefore, some morphological changes in craniocervical anatomy cause changes in the momentum and distribution of the load on the facet joints, predisposing the patient to facet arthropathy and osteoarthritis.

Assessing the predictive capability of machine learning models in determining clinical outcomes for patients with cervical spondylotic myelopathy treated with laminectomy and posterior spinal fusion

BACKGROUND

Cervical spondylotic myelopathy (CSM) is a prevalent degenerative condition resulting from spinal cord compression and injury. Laminectomy with posterior spinal fusion (LPSF) is a commonly employed treatment approach for CSM patients. This study aimed to assess the effectiveness of machine learning models (MLMs) in predicting clinical outcomes in CSM patients undergoing LPSF.

METHODS

A retrospective analysis was conducted on 329 CSM patients who underwent LPSF at our institution from Jul 2017 to Jul 2023. Neurological outcomes were evaluated using the modified Japanese Orthopaedic Association (mJOA) scale preoperatively and at the final follow-up. Patients were categorized into two groups based on clinical outcomes: the favorable group (recovery rates ≥ 52.8%) and the unfavorable group (recovery rates < 52.8%). Potential predictors for poor clinical outcomes were compared between the groups. Four MLMs-random forest (RF), logistic regression (LR), support vector machine (SVM), and k-nearest neighborhood (k-NN)-were utilized to predict clinical outcome. RF model was also employed to identify factors associated with poor clinical outcome.

RESULTS

Out of the 329 patients, 185 were male (56.2%) and 144 were female (43.4%), with an average follow-up period of 17.86 ± 1.74 months. Among them, 267 patients (81.2%) had favorable clinical outcomes, while 62 patients (18.8%) did not achieve favorable results. Analysis using binary logistic regression indicated that age, preoperative mJOA scale, and symptom duration (p < 0.05) were independent predictors of unfavorable clinical outcomes. All models performed satisfactorily, with RF achieving the highest accuracy of 0.922. RF also displayed superior sensitivity and specificity (sensitivity = 0.851, specificity = 0.944). The Area under the Curve (AUC) values for RF, Logistic LR, SVM, and k-NN were 0.905, 0.827, 0.851, and 0.883, respectively. The RF model identified preoperative mJOA scale, age, symptom duration, and MRI signal changes as the most significant variables associated with poor clinical outcomes in descending order.

CONCLUSIONS

This study highlighted the effectiveness of machine learning models in predicting the clinical outcomes of CSM patients undergoing LPSF. These models have the potential to forecast clinical outcomes in this patient population, providing valuable prognostic insights for preoperative counseling and postoperative management.

The Radiological Characteristics of Degenerative Cervical Kyphosis with Cervical Spondylotic Myelopathy

Introduction

In this study, we aim to describe the radiological characteristics of degenerative cervical kyphosis (DCK) with cervical spondylotic myelopathy (CSM) and discuss the relationship between DCK and the pathogenesis of spinal cord dysfunction.

Methods

In total, 90 patients with CSM hospitalized in our center from September 2017 to August 2022 were retrospectively examined in this study; they were then divided into the kyphosis group and the nonkyphosis group. The patients' demographics, clinical features, and radiological data were obtained, including gender, age, duration of illness, cervical Japanese Orthopaedic Association (JOA) score, cervical lordosis (CL), height of intervertebral space, degree of wedging vertebral body, degree of osteophyte formation, degree of disc herniation, degree of spinal cord compression, and anteroposterior diameter of the spinal cord. In the kyphosis group, kyphotic segments, apex of kyphosis, and segmental kyphosis angle were recorded. Radiological characteristics between the two groups were also compared. Correlation analysis was performed for different spinal cord compression types.

Results

As per our findings, the patients in the kyphosis group showed more remarkable wedging of the vertebral body, more severe anterior compression of the spinal cord, and a higher degree of disc herniation, while the posterior compression of the spinal cord was relatively mild when compared with the nonkyphosis group. CL was related to the type of spinal cord compression, as cervical kyphosis is an independent risk factor for anterior spinal cord compression.

Conclusions

DCK might play a vital role in the pathogenesis of spinal cord dysfunction. In patients with DCK, it was determined that the anterior column is less supported, and more severe anterior spinal cord compression is present. The anterior approach is supposed to be preferred for CSM patients with DCK.

Abnormal Static Sagittal Cervical Curvatures following Motor Vehicle Collisions: A Retrospective Case Series of 41 Patients before and after a Crash Exposure

Previous investigations have found a correlation between abnormal curvatures and a variety of patient complaints such as cervical pain and disability. However, no study has shown that loss of the cervical curve is a direct result of exposure to a motor vehicle collision (MVC). This investigation presents a retrospective consecutive case series of patients with both a pre-injury cervical lateral radiograph (CLR) and a post-injury CLR after exposure to an MVC. Computer analysis of digitized vertebral body corners on CLRs was performed to investigate the possible alterations in the geometric alignment of the sagittal cervical curve.

METHODS

Three spine clinic records were reviewed over a 2-year period, looking for patients where both an initial lateral cervical X-ray and an examination were performed prior to the patient being exposed to a MVC; afterwards, an additional exam and radiographic analysis were obtained. A total of 41 patients met the inclusion criteria. Examination records of pain intensity on numerical pain rating scores (NPRS) and neck disability index (NDI), if available, were analyzed. The CLRs were digitized and modeled in the sagittal plane using curve fitting and the least squares error approach. Radiographic variables included total cervical curve (ARA C2-C7), Chamberlain's line to horizontal (skull flexion), horizontal translation of C2 relative to C7, segmental translations (retrolisthesis and anterolisthesis), and circular modelling radii.

RESULTS

There were 15 males and 26 females with an age range of 8-65 years. Most participants were drivers (28) involved in rear-end impacts (30). The pre-injury NPRS was 2.7 while the post injury was 5.0; p < 0.001. The NDI was available on 24/41 (58.5%) patients and increased after the MVC from 15.7% to 32.8%, p < 0.001. An altered cervical curvature was identified following exposure to MVC, characterized by an increase in the mean radius of curvature (265.5 vs. 555.5, p < 0.001) and an approximate 8° reduction of lordosis from C2-C7; p < 0.001. The mid-cervical spine (C3-C5) showed the greatest curve reduction with an averaged localized mild kyphosis at these levels. Four participants (10%) developed segmental translations that were just below the threshold of instability, segmental translations < 3.5 mm.

CONCLUSIONS

The post-exposure MVC cervical curvature was characterized by an increase in radius of curvature, an approximate 8° reduction in C2-C7 lordosis, a mild kyphosis of the mid-cervical spine, and a slight increase in anterior translation of C2-C7 sagittal balance. The modelling result indicates that the post-MVC cervical sagittal alignment approximates a second-order buckling alignment, indicating a significant alteration in curve geometry. Future biomechanics experiments and clinical investigations are needed to confirm these findings.

Current Concepts of Cervical Spine Alignment, Sagittal Deformity, and Cervical Spine Surgery

There are not many reports on cervical spine alignment, and only a few analyze ideal surgical approaches and optimal amounts of correction needed for the various types of deformity. We comprehensively reviewed the present literature on cervical spinal deformities (with or without myelopathy) and their surgical management to provide a framework for surgical planning. A general assessment of the parameters actually in use and correlations between cervical and thoracolumbar spine alignment are provided. We also analyzed posterior, anterior, and combined cervical surgical approaches and indications for the associated techniques of laminoplasty, laminectomy and fusion, and anterior cervical discectomy and fusion. Finally, on the basis of the NDI, SF-36, VAS, and mJOA questionnaires, we fully evaluated the outcomes and measures of postoperative health-related quality of life. We found the need for additional prospective studies to further enhance our understanding of the importance of cervical alignment when assessing and treating cervical deformities with or without myelopathy. Future studies need to focus on correlations between cervical alignment parameters, disability scores, and myelopathy outcomes. Through this comprehensive literature review, we offer guidance on practical and important points of surgical technique, cervical alignment, and goals surgeons can meet to improve symptoms in all patients.

Positive Outcomes Following Cervical Acceleration-Deceleration (CAD) Injury Using Chiropractic BioPhysics® Methods: A Pre-Auto Injury and Post-Auto Injury Case Series

This series illustrates how rear-end impact motor vehicle collisions (MVCs) alter the cervical spine's alignment and demonstrates therapeutic use of cervical extension traction to improve lordotic alignment and other outcomes. This is a retrospective reporting of 7 adult patients (4 males and 3 females, 28-42 years) treated for cervical hypolordosis. These subjects received Chiropractic BioPhysics® (CBP®) rehabilitation and then were involved in a rear-end MVC. All cases had radiographic assessment that quantified the buckling of the cervical spine, presumably resulting directly from the CAD trauma. After an average of 3 years and 9 months (range: 1-7.6 years) following their initial program of care, the 7 patients sought care for a second time after the MVC. At this time, compared with their previously recorded post-treatment spine radiographs, there was an average 18.7° (range: 7.6-35.4°) reduction in cervical lordosis, a 9.2 mm (range: 3.6-19.8 mm) increase in anterior head translation (AHT), an 11.3° (range: 0.2-19.9°) decrease in the atlas plane line (APL), as well as a 35.7% (range: 22-52%) average neck disability index score (NDI) measured after the MVC. After the crash, a second round of CBP rehabilitation was administered, resulting in an average 15.1° improvement in cervical lordosis, 10.9 mm reduction in AHT, 10.4° increase in APL, and a 23.7% drop in NDI after an average of 35 treatments over 9 weeks. Treatment was universally successful, as an average 80% re-establishment of the lordosis toward its pre-injury state was found. There were no adverse events reported. This case series demonstrates that motor vehicle collisions may alter the alignment of the cervical spine. Rehabilitation of the cervical curve using extension traction improved the patients' initial pre-crash alignments toward their pre-injury alignments and was likely responsible for improvement in the patients' conditions. Clinical trials are needed to confirm these findings.

Clinicoradiological Risk Factors Associated with Inability to Achieve Minimum Clinically Important Difference in Operated Cases of Cervical Spondylotic Myelopathy

STUDY DESIGN

This is a retrospective cohort study.

PURPOSE

This study aimed to identify the clinicoradiological risk factors associated with the inability to achieve minimum clinically important difference (MCID) on the modified Japanese Orthopaedic Association (mJOA) Scale in operated cases of cervical spondylotic myelopathy (CSM).

OVERVIEW OF LITERATURE

Only a few studies have evaluated the outcomes of surgery performed for CSM using MCID on the mJOA scale.

METHODS

We analyzed 124 operated CSM cases from March 2019 to April 2021 for preoperative clinical features, cervical sagittal radiographic parameters, and magnetic resonance imaging (MRI) signal intensities (SI). The risk factors associated with missing the MCID (poor outcome) on mJOA at the final follow-up were identified using binary logistic regression. Multivariate analysis was used to find significant risk factors, and odds ratios (OR) were computed.

RESULTS

A total of 110 men (89.2%) and 14 women (10.8%) with an average age of 53.5±13.2 years were included in the analysis. During the last follow-up, 89 cases (72.1%) achieved MCID (meaningful gains following surgery) while 35 (27.9%) could not. The final model identified the following parameters as significant risk factors for poor outcome: increased duration of symptoms (OR, 6.77; p=0.001), lower preoperative mJOA scale (OR, 0.75; p=0.029), the presence of multilevel T2-weighted (T2W) MRI SI (OR, 4.79; p=0.004), and larger change in cervical sagittal vertical axis (ΔcSVA) (OR, 1.06; p=0.013). Also, an increase in cSVA postoperatively correlated with a reduced functional recovery rate (r=-0.4, p<0.001).

CONCLUSIONS

Surgery for CSM leads to significant functional benefits. However, poorer outcomes are observed in cases of greater duration of symptoms, higher preoperative severity with multilevel T2W MRI SI, and a larger increase in the postoperative cSVA (sagittal imbalance).

Influence of Preoperative Sagittal Alignment on Functional Recovery in Operated Cases of Cervical Spondylotic Myelopathy

Objective  We examine the influence of preoperative cervical sagittal curvature (lordotic or nonlordotic) on the functional recovery of surgically managed cases of cervical spondylotic myelopathy (CSM). The impact of sagittal alignment on the functional improvement of operated CSM cases has not been thoroughly investigated. Materials and Methods  We did retrospective analysis of consecutively operated cases of CSM from March 2019 to April 2021. Patients were grouped into two categories: lordotic curvature (with Cobb angle > 10 degrees) and nonlordotic curvature (including neutral [Cobb angle 0-10 degrees] and kyphotic [Cobb angle < 0 degrees]). Demographic data, and preoperative and postoperative functional outcome scores (modified Japanese Orthopaedic Association [mJOA] and Nurick grade) were analyzed for dependency on preoperative curvature, and correlations between outcomes and sagittal parameters were assessed. Results  In the analysis of 124 cases, 63.1% (78 cases) were lordotic (mean Cobb angle of 23.57 ± 9.1 degrees; 11-50 degrees) and 36.9% (46 cases) were nonlordotic (mean Cobb angle of 0.89 ± 6.5 degrees; -11 to 10 degrees), 32 cases (24.6%) had neutral alignment, and 14 cases (12.3%) had kyphotic alignment. At the final follow-up, the mean change in mJOA score, Nurick grade, and functional recovery rate (mJOArr) were not significantly different between the lordotic and nonlordotic group. In the nonlordotic group, cases with anterior surgery had a significantly better mJOArr than those with posterior surgery ( p  = 0.04), whereas there was similar improvement with either approach in lordotic cases. In the nonlordotic group, patients who gained lordosis (78.1%) had better recovery rates than those who had lost lordosis (21.9%). However, this difference was not statistically significant. Conclusion  We report noninferiority of the functional outcome in the cases with preoperative nonlordotic alignment when compared with those with lordotic alignment. Further, nonlordotic patients who were approached anteriorly fared better than those approached posteriorly. Although increasing sagittal imbalance in nonlordotic spines portend toward higher preoperative disability, gain in lordosis in such cases may improve results. We recommend further studies with larger nonlordotic subjects to elucidate the impact of sagittal alignment on functional outcome.

Cervical Spondylotic Myelopathy: From the World Federation of Neurosurgical Societies (WFNS) to the Italian Neurosurgical Society (SINch) Recommendations

Cervical spondylotic myelopathy (CSM) is a progressively growing pathology to afford by a spinal surgeon due to the aging of the population, associated with better treatment management and the best diagnosis and treatment solutions are greatly discussed. Nowadays that scientific literature is progressively increasing to identify the gold standard in diagnosis and treatment can be very challenging. This is particularly evident in spinal surgery with many different indications not only in different countries but also in the same local reality. In this scenario, many neurosurgical societies works to identify some guideline or recommendations to help spinal surgeons in daily practice. Furthermore, in an era in which legal issues are increasingly present in clinical practice to have some indications globally accepted can be very useful. World Federation of Neurosurgical Societies (WFNS) few years ago starts this process creating a list of recommendations originating from a worldwide steering committee to respect all the local reality. The spinal section of Italian Neurosurgical Society decides to adopt the WFNS recommendations with some revision basing on Italian scenario. The steering committee of the Spinal Section of Italian Neurosurgical Society identify 7 groups to review the literature of the last 10 years about different topics on CSM and to analyses the WFNS recommendations to adapt it to the Italian daily practice. The statements were discussed and voted in 2 sessions to obtain the final version. A list of recommendations on natural course and clinical presentation; diagnostic tests; conservative and surgical treatment; anterior, posterior and combined surgical treatment; role of neurophysiological monitoring and follow-up and outcome was created with only few new or revised statements respect the ones of WFNS. The Spine Section of Italian Neurosurgical Society create a list of recommendations that represent the more contemporary treatment concepts for CSM as presented in the highest quality clinical literature and best clinical practices available on this subject.

Concepts and Techniques to Prevent Cervical Spine Deformity After Spine Surgery: A Narrative Review

Adult cervical spine deformity is associated with decreased health-related quality of life, disability, and myelopathy. A number of radiographic parameters help to characterize cervical deformity and aid in the diagnosis and treatment. There are several etiologies for cervical spine deformity, the most common being iatrogenic. Additionally, spine surgery can accelerate adjacent segment degeneration which may lead to deformity. It is therefore important for all spine surgeons to be aware of the potential to cause iatrogenic cervical deformity. The aim of this review is to highlight concepts and techniques to prevent cervical deformity after spine surgery.

Predictors of poor clinical outcome in patients with cervical spondylotic myelopathy undergoing cervical laminectomy and fusion

BACKGROUND

Cervical spondylotic myelopathy (CSM) is a common degenerative disease that arises from spinal cord compression and injury. Laminectomy with posterior spinal fusion (LPSF) is one of the most common approaches used to treat patients with CSM. The present study aimed to evaluate predictors of poor clinical outcome in patients with CSM undergoing LPSF.

METHODS

We retrospectively evaluated 157 patients with CSM who underwent LPSF at our center between April 2014 and June 2019. The neurological outcome was assessed using the modified Japanese Orthopaedic Association (mJOA) scale before the surgery and at the last follow-up visit. Based on the clinical outcomes, all patients were divided into two groups [the good group (recovery rates ≥ 75%) and the poor group (recovery rates < 75%)]. The following suggested variables as potential predictors for the poor clinical outcome were compared between the two groups:age, gender, body mass index (BMI), smoking, diabetes, number of laminectomy levels, presence of signal changes in Magnetic Resonance Imaging (MRI), duration of symptoms, preoperative JOA scale, preoperative Pavlov ratio, preoperative cervical curvature, and preoperative cervical range of motion (ROM).

RESULTS

There were 86 males (54.8%) and 71 females (45.2%) with the mean follow-up time of 24.96 ± 1.67 months. Overall, 114 patients (72.6%) had a good clinical outcome. However, 43 subjects (27.4%) failed to achieve a good outcome. According to the binary logistic regression analysis, age (odds ratio [OR], 2.14; 95% confidence interval [95% CI], 1.87-2.63; P = 0.014) and preoperative JOA scale (OR, 3.73; 95% CI 2.96-4.87; p < 0.001) were independent predictors of poor clinical outcome.

CONCLUSIONS

The results of the present study showed that age and preoperative JOA scale were predictors of poor clinical outcome in patients with CSM undergoing LPSF. These findings will be of great value in preoperative counseling and management of postoperative expectations.

REVISION RECONSTRUCTION OF THE CERVICAL SPINE IN A PATIENT WITH EARLY DEEP SSI COMPLICATED BY ANGULAR KYPHOSIS: clinical case and literature review

Background. Deep surgical site infection (DSSI) is one of the most severe complications in spinal surgery. The timing and nature of DSSI are the determining criteria in the choice of treatment tactics. Aim. To present a unique clinical case of early deep SSI after ACDF in a patient with multisegmental degenerative spinal canal stenosis, complicated by epidural abscess and angular kyphotic deformity. Angular kyphosis correction, corpectomy of C4-6 and three-column cervical reconstruction were performed in one surgical session. Case presentation. A 57-year-old patient was admitted to the clinic after staged surgical interventions on the cervical spine for multilevel degenerative stenosis of the spinal canal. The primary surgical interventions were complicated by DSSI in the early period after the second surgery with formation of angular kyphosis of the cervical spine. The patient underwent revision one-stage reconstructive intervention to correct the deformity, decompress the spinal canal, and three-column reconstruction of C3-7 segments. Long-term follow-up showed persistent reduction of pain syndrome, improved quality of life and absence of recurrence of DSSI. Conclusion. The presented case illustrates the possibilities of one-stage revision three-column cervical spine reconstruction for correction of sagittal profile, decompression of intracanal neural structures and ensuring stability of operated segments. Use of DSSI treatment algorithms based on Prinz V. and Vajkoczy P. classification contributes to the selection of the optimal tactics of patient management.

Comparing Combined Anterior and Posterior to Posterior-Only Decompression and Fusion Crossing the Cervico-Thoracic Junction in Octogenarians

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The purpose of the study was to compare early complication, morbidity and mortality risks associated with fusion surgery crossing the cervico-thoracic junction in patients aged over 80 years undergoing combined anterior and posterior approach versus a posterior-only approach.

METHODS

We retrospectively identified octogenarian patients with myelopathy who underwent fusion crossing the cervico-thoracic junction. Patient demographics, Nurick score, surgical characteristics, complications, hospital course, early outcome and 90-day mortality were collected. Comorbidities were classified using the age-adjusted Charlson Comorbidity Index (AACCI). Radiographic measurements for deformity correction included the C2-C7 sagittal Cobb angle, C2-7 sagittal vertical axis and T1 slope pre- and postoperatively.

RESULTS

Out of 8,521 surgically treated patients, 12 octogenarian patients had a combined anterior and posterior approach (AP group) and 14 were treated from posterior-only (P group). Mean age was 81.4 ± 1.2 and 82.5 ± 2.7 years, respectively. There was no significant difference in Nurick scores between the groups (P > 0.05). The major complication risk in the AP group was significantly higher, requiring PEG tube placement due to severe dysphagia in 4 patients (33%) compared to none in the P group. A greater improvement in cervical lordosis could be achieved through a combined approach. The 90-day mortality risk was 8% for the AP group and 0% for the P group.

CONCLUSIONS

A combined anterior and posterior approach is associated with a significantly higher major complication rate and can result in severe dysphagia requiring PEG tube placement in one-third of patients over 80 years of age.

Incidence of cervical kyphosis and cervical posterior translation in neck pain associated with radiological evidence of degenerative disc disease

BACKGROUND

Cervical kyphosis mechanically influences the intervertebral discs, which may lead to neck, shoulder, and scapular pain.

OBJECTIVES

To investigate the incidence of cervical kyphosis and posterior displacement of cervical vertebrae (cervical posterior translation index) in patients with radiologically evident degenerative disc disease.

DESIGN

Retrospective-cohort study.

METHODS

Ninety-five patients with radiologically evident degenerative disc disease were recruited at our clinic from 2015 to 2019. Radiography images were used to analyze the straight-line index in each patient in the upright posture. The straight-line index was calculated by drawing a reference line connecting the posterior inferior edges of C2 to C7 and normalizing the addition of the distances from the posterior inferior edges of C3, C4, C5, and C6 to the reference line, respectively. Straight-line index <0 was defined as cervical kyphosis and ≥0 as cervical lordosis, the cervical kyphosis. In cervical kyphosis group, the distance from the posterior inferior edges of C3, C4, C5, and C6 to the reference line was normalized by the reference line distance to determine posterior displacement. Multiple comparison tests aside from simple and multiple linear regression analysis were performed.

RESULTS

The incidence of cervical kyphosis in patients with radiologically evident degenerative disc disease was 60% (57/95 patients). Multiple comparison tests revealed that the cervical posterior translation indexes of C4 and C5 were significantly higher than those of C3, C4, and C6, in cervical kyphosis group.

CONCLUSIONS

Cervical kyphosis was present in 60% of patients with radiologically evident degenerative disc disease, with C5 showing the most posterior displacement.

Cervical Sagittal Alignment in Patients with Cervical Spondylotic Myelopathy: An Observational Study From the Canadian Spine Outcomes and Research Network

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Among patients with CSM, we aimed to evaluate the extent to which: (1) Preoperative cervical sagittal alignment is associated with health-related quality of life, function, and symptoms; (2) Surgery leads to changes in cervical sagittal alignment; and (3) Postoperative cervical sagittal alignment is associated with health-related quality of life, function, and symptoms at 12 months of follow-up.

SUMMARY OF BACKGROUND DATA

The importance of maintaining or improving cervical sagittal alignment in the surgical management of patients with CSM has not been established.

METHODS

We measured C2-C7 Cobb angle, T1 slope, and C2-C7 cervical sagittal vertical axis (cSVA). We tested for associations with Neck Disability Index, Pain Scales for neck and arm pain, EuroQol 5D, Short Form 12 Physical and Mental Component Summaries, and modified Japanese Orthopaedic Association scores. We adjusted for potential confounders using multiple linear regression, and we performed various prespecified subgroup (cSVA > 40 mm, surgical approach) and sensitivity analyses.

RESULTS

Among 250 patients, adjusted analyses yielded significant inverse associations prior to surgery between each of cSVA and T1 slope with SF12 Physical Component Summaries (T1 slope: -0.14, 95% CI -0.26 to -0.01, P = 0.03; C2-C7 cSVA: -0.13, 95% CI --0.21 to -0.05 P < 0.01). Surgery was associated with a small but statistically significant increase in cSVA across the cohort (+5.8 mm [SD 11.7], P < 0.01) but no change in Cobb angle or T1 slope. At 12-months after surgery, there were no significant associations between alignment parameters or change in alignment and any measures of health-related quality of life, function, or symptoms. Results were consistent across subgroup and sensitivity analyses.

CONCLUSION

Increased cSVA and T1 slope were associated with inferior health-related quality of life at presentation among patients with CSM, but no significant associations were observed following surgical treatment.Level of Evidence: 3.

Anterior Canal Reconstruction and Fusion for Myelopathy Caused by Degenerative Cervical Kyphosis and Stenosis With or Without Ossification of the Posterior Longitudinal Ligament

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To introduce an anterior surgical technique for myelopathy caused by degenerative cervical kyphosis and stenosis (DCKS) with or without ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

The optimal approach in the treatment of DCKS remains a controversy because each anterior or posterior route surgery has advantages and disadvantages.

MATERIALS AND METHODS

In the period from June 2017 through June 2019, a consecutive cohort of adults diagnosed with DCKS underwent anterior canal reconstruction and fusion (ACRF). All patients underwent x-ray, computed tomography, and magnetic resonance imaging of the cervical spine. Radiologic assessment included kyphosis, canal area, canal reconstruction, OPLL, and spinal cord curvature and morphology. The Japanese Orthopaedic Association (JOA) scoring system was used to evaluate the neurological status. Surgery-related and implant-related complications were all recorded. Follow-up was carried out at 3, 6, 12, 24, and 36 months postoperation.

RESULTS

Fourty-one patients were included in the study, of which 19 presented with OPLL. Postoperatively, the canal area were significantly greater at last follow-up compared with preoperation (208.4 vs. 123.2 mm2; P=0.001). There was significant kyphosis correction (-17.6 vs. 8.5 degrees, P=0.001) at last follow-up. Ninety-six segmental canal reconstruction were performed, 89 (92.7%) reached bone fusion at both grooves with a mean time of 7.9 months. On sagittal magnetic resonance imaging, 33 (80.5%) patients presented with lordosis in the spinal cord curvature, 8 (19.5%) with straight. The mean JOA score at last follow-up was significantly better than preoperation (15.0 vs. 9.3 points; P<0.01). One patient presented with cerebrospinal fluid leakage, 1 with screw displacement and 2 with dysphagia.

CONCLUSION

ACRF, receiving good correction of kyphosis, amplified canal area, solid instrumented fusion and circumferential decompression, is an effective and safe surgical technique for cervical myelopathy caused by DCKS with or without OPLL.

LEVEL OF EVIDENCE

Level III-a retrospective analysis.

Risk factors for the development of degenerative cervical myelopathy: a review of the literature

Degenerative cervical myelopathy (DCM) encompasses various pathological conditions causing spinal cord (SC) impairment, including spondylosis (multiple level degeneration), degenerative disc disease (DDD), ossification of the posterior longitudinal ligament (OPLL), and ossification of the ligamentum flavum (OLF). It is considered the most common cause of SC dysfunction among the adult population. The degenerative phenomena of DDD, spondylosis, OPLL and OLF, is likely due to both inter-related and distinct factors. Age, cervical alignment, and range of motion, as well as congenital factors such as cervical cord-canal mismatch due to congenital stenosis, Klippel-Feil, Ehler-Danlos, and Down syndromes have been previously reported as potential factors of risk for DCM. The correlation between some comorbidities, such as rheumatoid arthritis and movement disorders (Parkinson disease and cervical dystonia) and DCM, has also been reported; however, the literature remains scare. Other patient-specific factors including smoking, participation in contact sports, regular heavy load carrying on the head, and occupation (e.g. astronauts) have also been suggested as potential risk of myelopathy development. Most of the identified DCM risk factors remain poorly studied however. Further researches will be necessary to strengthen the current knowledge on the subject, especially concerning physical labors in order to identify patients at risk and to develop an effective treatment strategy for preventing this increasing prevalent disorder.

Audit and Comparison Between Radiographic Markers of Gaze Direction Using EOS Imaging - An Essential Step to Streamline Existing Methods

STUDY DESIGN

Retrospective cohort study on prospectively implemented EOS protocol.

OBJECTIVE

This study aims to audit and compare existing radiological definitions of gaze direction-chin brow vertical angle (CBVA), McGregor slope (McGS), slope of line of sight (SLS), orbital-internal occipital protuberance (OIOP) slope angle, and Tangent to the hard palate (THP) in a neutral, healthy, and asymptomatic cohort.

SUMMARY OF BACKGROUND DATA

The ability to accurately define direction of gaze is the first step when striving for horizontal gaze restoration in any affected individual with rigid sagittal deformity. Yet, the radiological definition of gaze direction remains poorly standardized.

METHODS

Hundred healthy subjects who could achieve horizontal gaze underwent whole-body standing EOS radiographs taken under a strictly standardized protocol. Radiographic measurements of global spinal sagittal parameters and surrogate measures of horizontal gaze were analyzed and compared.

RESULTS

The mean age was 45 ± 15.9 years, with a balanced male-to-female-ratio. Their C7 SVA was -7.7 mm ± 24.8 mm, PI was 51.0o ± 11.4o, PI-LL was -0.9o ± 13.0o and T1-slope was 21.2o ± 9.2o. Measured horizontal gaze parameters were as follows: CBVA (1.07o ± 5.48o), McGS (-3.23o ± 5.63o), SLS (0.45o ± 5.34o), OIOP (5.03o ± 4.66o), THP (-0.17o ± 6.27o). CBVA correlated strongly with McGS (r = 0.679, P < 0.001), SLS (r = 0.592, P < 0.001), OIOP (r = 0.697, P < 0.001), and THP (r = -0.504, P < 0.001). OIOP had the lowest variance amongst all parameters and showed less variability compared to CBVA (SD 4.66 Var 21.69 vs. SD 5.48 Var 30.08, P = .012). Multivariate analysis showed that C2-7 angle was the only parameter found to be associated with OIOP values (P = 0.006).

CONCLUSION

OIOP is the least variable, and most robust radiological method in determining gaze direction. It uses easily recognizable anatomical landmarks and an angular criterion, which makes it advantageous both with x-rays or slot scanners.Level of Evidence: 3.

Association between pre-operative sagittal alignment and radiographic measures of decompression following cervical laminectomy: a retrospective cohort study

Background

The primary purpose of this study was to determine the association between pre-operative cervical sagittal alignment and the extent of cord decompression in the form of increased spinal cord width and cerebrospinal fluid (CSF) space in front of and behind the cord in patients undergoing laminectomy for cervical spondylotic myelopathy (CSM). Secondary objectives included an assessment of the correlation between increasing numbers of levels decompressed and the post-operative cervical spine sagittal alignment, the effect of laminectomy on the change in alignment, as well as effect of laminectomy on pre-existing spinal cord signal abnormality.

Methods

This retrospective cohort study included patients who underwent cervical laminectomies, without fusion, between 2015 and 2020. Chart review was used to collect baseline variables. Cervical sagittal alignment, width of the spinal cord, and the CSF space in-front and behind the cord was measured pre-operatively and post-operatively using magnetic resonance imaging (MRI) scans for each patient. The correlation between change in measured parameters and pre-operative cervical sagittal alignment was assessed using Spearman's correlation.

Results

Thirty-five patients were included. Average age was 65.29±10.98 years old. The majority of patients (80%) underwent laminectomies at 3-4 levels. Average pre-operative sagittal alignment determined by the Cobb angle was 6.05°±14.17°, while the average post-operative Cobb angle was 3.15°±16.64°. The change in Cobb angle was not statistically significant (P=0.998). Eleven patients (32%) had pre-operative kyphotic sagittal alignment. The average time from surgery to post-operative MRI scan was 20.44±13.18 months (range, 3-39; median, 18.5; IQR, 23.5). There was no statistically significant association between increasing levels of decompression and change in alignment (P=0.546). Cord signal abnormality persisted after decompression. There was a moderate correlation between lordotic pre-operative cervical sagittal alignment and change in space in-front of the cord (correlation coefficient 0.337, P=0.048) and change in cord width (correlation coefficient 0.388, P=0.021).

Conclusions

Severity of pre-operative kyphotic sagittal alignment is associated with decreased spinal cord drift and extent of decompression. The pre-operative sagittal alignment is not significantly associated with the change in post-operative alignment. Increasing number of levels decompressed does not worsen a kyphotic cervical spine sagittal alignment.

Restoring cervical lordosis by cervical extension traction methods in the treatment of cervical spine disorders: a systematic review of controlled trials

[Purpose] To systematically review the literature on the use of cervical extension traction methods for increasing cervical lordosis in those with hypolordosis and cervical spine disorders. [Methods] Literature searches for controlled clinical trials were performed in Pubmed, PEDro, Cochrane, and ICL databases. Search terms included iterations related to the cervical spine, neck pain and disorders, and extension traction rehabilitation. [Results] Of 1,001 initially located articles, 9 met the inclusion/exclusion criteria. The trials demonstrated increases in radiographically measured lordosis of 12-18°, over 5-15 weeks, after 15-60 treatment sessions. Untreated controls/comparison groups not receiving extension traction showed no increase in cervical lordosis. Several trials demonstrated that both traction and comparison treatment groups experienced immediate pain relief. Traction treatment groups maintained their pain and disability improvements up to 1.5 years later. Comparative groups not receiving lordosis improvement experienced regression of symptoms towards pre-treatment values by 1 years' follow-up. [Conclusion] There are several high-quality controlled clinical trials substantiating that increasing cervical lordosis by extension traction as part of a spinal rehabilitation program reduces pain and disability and improves functional measures, and that these improvements are maintained long-term. Comparative groups who receive multimodal rehabilitation but not extension traction experience temporary relief that regresses after treatment cessation.

Demonstration of central conduction time and neuroplastic changes after cervical lordosis rehabilitation in asymptomatic subjects: a randomized, placebo-controlled trial

A randomized controlled study was conducted to evaluate the effect of rehabilitation of the cervical sagittal configuration on sensorimotor integration and central conduction time in an asymptomatic population. Eighty (32 female) participants with radiographic cervical hypolordosis and anterior head translation posture were randomly assigned to either a control or an experimental group. The experimental group received the Denneroll cervical traction while the control group received a placebo treatment. Interventions were applied 3 × per week for 10 weeks. Outcome measures included radiographic measured anterior head translation distance, cervical lordosis (posterior bodies of C2–C7), central somatosensory conduction time (latency) (N13–N20), and amplitudes of potentials for spinal N13, brainstem P14, parietal N20 and P27, and frontal N30. Outcomes were obtained at: baseline, after 10 weeks of intervention, and at 3 months follow up. After 10 weeks and 3-months, between-group analyses revealed statistically significant differences between the groups for the following measured variables: lordosis C2–C7, anterior head translation, amplitudes of spinal N13, brainstem P14, parietal N20 and P27, frontal N30 potentials (P < 0.001), and conduction time N13–N20 (P = 0.004). Significant correlation between the sagittal alignment and measured variables were found (P < 0.005). These findings indicate restoration of cervical sagittal alignment has a direct influence on the central conduction time in an asymptomatic population.

Surgical anatomy of microsurgical 3-level anterior cervical discectomy and fusion C4-C7

Anterior cervical discectomy and fusion (ACDF) is one of the most common spinal procedures, frequently used for the treatment of cervical spine degenerative diseases. It was first described in 1958. Interestingly, to our knowledge, 3-level ACDF has not been previously published as a peer-reviewed video case with a detailed description of intraoperative microsurgical anatomy. In this video, we present the case of a 33-year-old male who presented with a combination of myelopathy (hyperreflexia and long tract signs in the upper and lower extremities) and bilateral radiculopathy of the upper extremities. He had been previously treated conservatively with physical therapy and pain management for 6 months without success. We performed 3-level microsurgical ACDF from C4 to C7. All 3 levels were decompressed, and bone allografts were placed to achieve intervertebral body fusion. A titanium plate was utilized from C4 to C7 for internal fixation. The patient was discharged home on the first postoperative day. His pain, numbness and tingling resolved, as well as his myelopathy. No perioperative complications were encountered. Herein we present the surgical anatomy of our operative technique including certain technical tips. Written consent was obtained directly from the patient.

Cervical Deformity: Evaluation, Classification, and Surgical Planning

Cervical deformity is a challenging condition to treat and requires complex decision-making. Apart from a thorough history and physical examination, a thoughtful and quantitative analysis of multiple imaging modalities is critical for understanding the nature and driver of the cervical deformity. A few classification schemes have emerged, and it is now clear that dynamic films are invaluable as they capture the extension reserve that patients can use to compensate for malalignment. These classification systems can help guide surgical planning, because the various subgroups have different properties that lend themselves to specific treatment paradigms. Here we review the clinical and radiographic evaluation, classification, and surgical planning for cervical deformity.

The Impact of Older Age on Functional Recovery and Quality of Life Outcomes after Surgical Decompression for Degenerative Cervical Myelopathy: Results from an Ambispective, Propensity-Matched Analysis from the CSM-NA and CSM-I International, Multi-Center Studies

Background: The effect on functional and quality of life (QOL) outcomes of surgery in elderly degenerative cervical myelopathy (DCM) patients has not been definitively established. Objective: To evaluate the effect of older age on the functional and QOL outcomes after surgery in an international, multi-center cohort of patients with DCM. Methods: 107 patients aged over 70 years old (mean 75.6 ± 4.4 years) were enrolled in the AOSpine CSM-North America and International studies. A propensity-matched cohort of 107 patients was generated from the remaining 650 adults aged <70 years old (mean 56.3 ± 9.6 years), matched to gender, complexity of surgery, co-morbidities, and baseline functional impairment (modified Japanese Orthopedic Association scale (mJOA). Functional, disability, and QOL outcomes were compared at baseline and at two years post-operatively, along with peri-operative adverse events. Results: Both cohorts were equivalently matched. At two years, both cohorts showed significant functional improvement from the baseline but the magnitude was greater in the younger cohort (mJOA 3.8 (3.2–4.4) vs. 2.6 (2.0–3.3); p = 0.007). This difference between groups was also observed in the SF-36 physical component summary (PCS) and mental component summary (MCS) outcomes (p = <0.001, p = 0.007), but not present in the neck disability index (NDI) scores (p = 0.094). Adverse events were non-significantly higher in the elderly cohort (22.4% vs. 15%; p = 0.161). Conclusions: Elderly patients showed an improvement in functional and QOL outcomes after surgery for DCM, but the magnitude of improvement was less when compared to the matched younger adult cohort. An age over 70 was not associated with an increased risk of adverse events.

Outcome Measures and Variables Affecting Prognosis of Cervical Spondylotic Myelopathy: WFNS Spine Committee Recommendations

This study is conducted to review the literature systematically to determine most reliable outcome measures, important clinical and radiological variables affecting the prognosis in cervical spondylotic myelopathy patients. A literature search was performed for articles published during the last 10 years. As functional outcome measures we recommend to use modified Japanese Orthopaedic Association scale, Nurick’s grade, and Myelopathy Disability Index. Three clinical variables that affect the outcomes are age, duration of symptoms, and severity of the myelopathy. Examination findings require more detailed study to validate their effect on the outcomes. The predictive variables affecting the outcomes are hand atrophy, leg spasticity, clonus, and Babinski’s sign. Among the radiological variables, the curvature of the cervical spine is the most important predictor of prognosis. Patients with instability are expected to have a poor surgical outcome. Spinal cord compression ratio is a critical factor for prognosis. High signal intensity on T2-weighted magnetic resonance images is a negative predictor for prognosis. The most important predictors of outcome are preoperative severity and duration of symptoms. T2 hyperintensity and cord compression ratio can also predict outcomes. New radiological tests may give promising results in the future.

Spinal alignment, surgery, and outcomes in cervical deformity: A practical guide to aid the spine surgeon

Compared to the thoracolumbar spine, the literature on cervical spine alignment is scarce. While a consistent number of articles have been published, few analyze the ideal surgical approaches for each type of deformity and the optimal amount of correction to achieve. This paper provides a comprehensive review of current literature on cervical spinal deformities (with or without myelopathy) and their surgical management; it is our goal to create a framework on which surgical planning can be made. A general assessment of the actually utilized parameters and correlation between the cervical and thoracolumbar spine alignment is presented. Moreover, we provide an analysis of cervical surgical approaches (anterior, posterior, or combined), techniques (laminoplasty, laminectomy and fusion, anterior cervical discectomy and fusion, corpectomy), and their indications. Finally, a complete evaluation of outcomes and postoperative health-related quality of life (HRQOL) measures based on questionnaires (NDI, VAS, SF-36, mJOA) is discussed. Several prospective studies would be useful in understanding how cervical alignment may be important in the assessment and treatment of cervical deformities with or without myelopathy. In particular, future works should concentrate on the correlation between cervical alignment parameters, disability scores, and myelopathy outcomes. We propose, via comprehensive literature review, a guide of practical key points on surgical techniques, cervical alignment, and symptom improvement goals surgeons should aim to achieve for each patient.