Cervical myelopathy caused by C3-C4 spondylosis in elderly patients: a radiographic analysis of pathogenesis

Age is Associated with Level of First-Time Anterior Cervical Discectomy and Fusion: An Ordinal Analysis of Factors Influencing Timing of Cervical Degeneration

BACKGROUND

Symptomatic cervical spondylosis is often treated with anterior cervical discectomy and fusion (ACDF). However, few factors can predict which cervical level will degenerate and require intervention. This analysis evaluates preprocedural factors associated with level of first-time single-level ACDF.

METHODS

We performed a retrospective analysis of patients who underwent single-level ACDF without prior history of spine surgery. Mann Whitney U-tests and Spearman rank-order correlation were performed for analyses of associations between variables of interest and ACDF level. Adjusted odds-ratios were calculated by proportional-odds logistic regression, with age, sex, body mass index, current tobacco use, history of neck trauma, preoperative radicular symptoms, and preoperative myelopathic symptoms as covariates.

RESULTS

One hundred forty-one patients met inclusion criteria, and age demonstrated a negative correlation with ACDF level, such that younger patients tended to have ACDF performed at inferior subaxial levels (P = 0.0006, rho = -0.31, moderately strong relationship). Patients with preoperative radicular symptoms and myelopathic symptoms were more likely to have ACDF performed at inferior (P = 0.0001) and superior (P < 0.0001) levels, respectively. Patient sex, body mass index, current tobacco use, and history of neck trauma were not predictive of ACDF level. When adjusting for the above variables in a proportional-odds ordinal logistic regression model, a one-year increase in age conferred a 4% increase in the odds of requiring an ACDF at a given superior level compared to the adjacent inferior level.

CONCLUSIONS

Age is correlated with level of first-time single level ACDF. Individual subaxial levels may have unique biomechanical properties that influence degeneration.

Feasibility of total and partial uncinectomy during anterior cervical approach: MRI-based analysis of 176 patients regarding vertebral artery location

PURPOSE

To determine the technical feasibility of uncinate process (UP) resection (uncinectomy) during anterior cervical approach with risk-avoidance of vertebral artery (VA) injury.

METHODS

One hundred and seventy-six magnetic resonance imaging images with cervical spondylosis were evaluated. The diameter between UP and VA (UP-VA distance), the presence of a fat plane, and the VA's anterior-posterior position relative to UP (anterior[A], middle[M], posterior[P]) at C3-4 to C6-7 segments were investigated. Subsequently, easy-to-use classifications were developed according to the feasibility of total and partial uncinectomy. Total uncinectomy: easy (distance: > 2 mm); moderate (distance: ≤ 2 and fat plane: +); advanced (no fat plane). Partial uncinectomy: easy (distance: > 2 mm and P, A, or M position); moderate (distance: ≤ 2; fat plane: + and P position), and advanced (no fat plane and P position).

RESULTS

UP-VA distance of C5-6 on the right side (left/right: 0.41/0.31 mm) was the smallest. The ratio of no fat plane of C5-6 (46.6%/49.4%) was the highest. C5-6 had a high rate of P position (7.4%/8.5%) while C6-7 had a high rate of A position (19.3%/18.2%). More than 90% individuals were classified as easy for partial uncinectomy at any vertebral segment (C3-7), while more than 30% were classified as advanced at C4-7 with the highest rate at C5-6 for total uncinectomy.

CONCLUSION

When performing uncinectomy during the anterior cervical approach, the C5-6 segment may be at the greatest risk of VA injury. Hence, preoperative MR images should be thoroughly evaluated to avoid VA injury.

Residual anterior cord compression after laminoplasty for cervical spondylotic myelopathy: evaluation of risk factors according to the most severely stenotic vertebral segment

OBJECTIVE

Residual anterior spinal cord compression (RASCC) after cervical laminoplasty, which has been confirmed on postoperative MRI, is reportedly associated with poor clinical outcomes. To date, only a few studies have described the risk factors associated with RASCC. The aim of this study was to identify the factors that can predict the occurrence of RASCC after laminoplasty for cervical spondylotic myelopathy (CSM), focusing on the location of the most stenotic segment.

METHODS

In this retrospective, single-center study, 120 patients who underwent C3-7 laminoplasty for multilevel CSM were included. Different techniques were used for C3 decompression, i.e., partial (dome-laminotomy) or complete (laminoplasty/laminectomy) decompression. RASCC was diagnosed using MRI conducted 3 weeks postoperatively. The patients were divided into two groups according to the segment with the most severe stenosis (Seg-MSS; C3-4 vs C4-7). Demographics, radiological data, and C3 decompression technique were compared between the two groups. Furthermore, intergroup comparisons were performed based on Seg-MSS. A logistic regression model was constructed to identify the factors predicting RASCC after patient stratification according to Seg-MSS.

RESULTS

Forty patients (33.3%) had RASCC. The patients with Seg-MSS at C3-4 (51.3%) had a significantly higher incidence of RASCC (p = 0.003) than those with Seg-MSS at C4-7 (24.7%). Logistic regression analysis showed that in patients with Seg-MSS at C3-4, C3 partial decompression demonstrated a greater association with RASCC as opposed to complete decompression. Conversely, in patients with Seg-MSS at C4-7, kyphotic segmental lordotic angle was associated with an increased risk of RASCC.

CONCLUSIONS

The risk factors for RASCC differed depending on the location of the most stenotic segment (C3-4 vs C4-7). If there is segmental kyphosis at the most stenotic segment at C4-7, anterior decompression and fusion should be considered. If C3-4 is the most stenotic segment, anterior surgery is also recommended, but alternatively, one can choose laminoplasty with complete C3 laminectomy and resection of the C2-3 ligamentum flavum.

Segmental cervical instability does not drive the loss of cervical lordosis after laminoplasty in patients with cervical spondylotic myelopathy

BACKGROUND/CONTEXT

Kyphotic deformity after cervical laminoplasty (CLP) often leads to unfavorable neurological recovery due to insufficient indirect decompression of the spinal cord. Existing literature has described that segmental cervical instability is a contraindication for CLP because it is a potential risk factor for kyphotic changes after surgery; however, this has never been confirmed in any clinical studies.

PURPOSE

To confirm whether segmental cervical instability was an independent risk factor for postoperative kyphotic change and to examine whether segmental cervical instability led to poor neurological outcomes after CLP for cervical spondylotic myelopathy (CSM).

STUDY DESIGN/SETTING

A retrospective study PATIENT SAMPLE: Patients who underwent CLP for CSM between January 2013 and January 2021 with a follow-up period of ≥1 year were enrolled.

OUTCOME MEASURES

Cervical radiographic measurements including C2-C7 lordosis (C2-7 angle), cervical sagittal vertical axis, C7 slope, flexion range of motion (fROM) and extension ROM (eROM) were assessed using neutral and flexion-extension views. Segmental cervical instability was classified into anterolisthesis (AL) of ≥2 mm displacement, retrolisthesis (RL) of ≥2 mm displacement, and translational instability (TI) of ≥3 mm translational motion. The amount of C2-7 angle loss at the follow-up period compared to the preoperative measurements was defined as cervical lordosis loss (CLL). Neurological outcomes were assessed using the recovery rate of the Japanese Orthopedic Association score (JOA-RR).

METHODS

CLL was compared among patients with and without segmental cervical instability. Further, multiple linear regression model for CLL was built for the evaluation with adjustment of the reported risks, including cervical sagittal vertical axis, C7 slope, fROM, eROM, and patient age together with AL, RL, and TI, as independent variables. The JOA-RR was also compared between patients with and without segmental cervical instability.

RESULTS

A total of 138 patients (mean age, 68.7 years; 65.9% male) were included in the analysis. AL, RL, and TI were found in 12 (8.7%), 33 (23.9%), and 16 (11.6%) patients, respectively. Comparisons among the groups showed that AL led to greater CLL; however, RL and TI did not. Multiple linear regression analysis revealed that greater CLL is significantly associated with greater fROM and smaller eROM (regression coefficient [β]=0.328, 95% confidence interval: 0.178 to 0.478, p<.001; β=-0.372, 95% confidence interval: -0.591 to -0.153, p=.001, respectively). However, there were no significant statistical associations in the AL, RL, and TI. Whereas, patients with AL tended to exhibit lower JOA-RR than those without AL (37.8% vs. 52.0%, p=.108).

CONCLUSIONS

Segmental cervical instability is not the definitive driver for loss of cervical lordosis after CLP in patients with CSM; thus, is not a contraindication in and of itself. However, it is necessary to consider the indications for CLP, according to individual cases of patients with AL on baseline radiograph, which is a sign of poor neurological recovery.

Influence of Intervertebral Level of Stenosis on Neurological Recovery and Reduction of Neck Pain After Posterior Decompression Surgery for Cervical Spondylotic Myelopathy: A Retrospective Multicenter Study with Propensity Scoring

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

To identify the impact of the intervertebral level of stenosis on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

As the upper affected cervical levels in elderly patients result from degenerative changes in the lower cervical levels with aging, it is usually difficult to determine the influence of the upper affected cervical levels on surgical outcomes after posterior decompression for CSM in older age.

METHODS

This study involved 636 patients with CSM who underwent posterior decompression. According to the most stenotic intervertebral level, patients were divided into upper (n = 343, the most stenotic intervertebral level was C2/3, C3/4, or C4/5) and lower (n = 293, the most stenotic intervertebral level was C5/6, C6/7, or C7/T1) cervical stenosis groups. Propensity score matching of the baseline factors (characteristics, comorbidities, and neurological function) was performed to compare surgical outcomes, the Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) for neck pain between the upper (n = 135) and lower (n = 135) cervical stenosis groups.

RESULTS

Before propensity score matching, age at surgery was older and pre- and postoperative JOA scores were lower in the upper cervical stenosis group (P < 0.001, P < 0.001, and P < 0.001, respectively). Following matching, baseline factors were comparable between the groups. Postoperative JOA scores, preoperative-to-postoperative changes in the JOA scores, and the JOA score recovery rate were not significantly different between the groups (P = 0.866, P = 0.825, and P = 0.753, respectively). No differences existed in postoperative VAS for neck pain and preoperative-to-postoperative changes in VAS for neck pain between the groups (P = 0.092 and P = 0.242, respectively).

CONCLUSION

The intervertebral level of stenosis did not affect surgical outcomes after posterior decompression for CSM.Level of Evidence: 3.

Effect of Minimally Invasive Selective Laminectomy for Cervical Spondylotic Myelopathy on Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective analysis of prospectively collected observational data.

OBJECTIVE

This study aimed to evaluate the slippage, sagittal alignment, and range of motion (ROM) after selective laminectomy (SL) in patients who had cervical spondylotic myelopathy (CSM) with degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

Clinical outcomes have been reported for both decompression and fusion surgeries for DS of the lumbar spine. However, only a few reports have examined cervical spine spondylolisthesis.

MATERIALS AND METHODS

This study included 178 patients who underwent SL for CSM. Those with ossification of the posterior longitudinal ligament were excluded. Slippage >2 mm was defined as spondylolisthesis, and spondylolisthesis progression was defined as an additional displacement >2 mm on a neutral radiograph. The slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were examined before and ≥2 years after surgery. Radiologic parameters were evaluated according to the slip direction and the number of laminae removed.

RESULTS

DS was observed in 29 patients (16.3%); 24 patients, comprising 9 and 15 in the anterolisthesis and retrolisthesis groups, respectively, were successfully followed up for more than 2 years. Preoperative and postoperative radiologic changes in slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were not remarkable in either group regardless of the number of laminae removed. Revision surgery for the progression of DS and alignment deterioration was not required in any patient of either group.

CONCLUSIONS

SL does not affect DS, sagittal alignment, or ROM irrespective of the slip direction and the number of laminae removed, even after >2 years after surgery. Given the preservation of the posterior elements, SL may be an effective treatment for CSM with DS.

LEVEL OF EVIDENCE

Level IV.

Biomechanical Analysis of Posterior Ligaments of Cervical Spine and Laminoplasty

Cervical laminoplasty is a valuable procedure for myelopathy but it is associated with complications such as increased kyphosis. The effect of ligament damage during cervical laminoplasty on biomechanics is not well understood. We developed the C2–C7 cervical spine finite element model and simulated C3–C6 double-door laminoplasty. Three models were created (a) intact, (b) laminoplasty-pre (model assuming that the ligamentum flavum (LF) between C3–C6 was preserved during surgery), and (c) laminoplasty-res (model assuming that the LF between C3–C6 was resected during surgery). The models were subjected to physiological loading, and the range of motion (ROM), intervertebral nucleus stress, and facet contact forces were analyzed under flexion/extension, lateral bending, and axial rotation. The maximum change in ROM was observed under flexion motion. Under flexion, ROM in the laminoplasty-pre model increased by 100.2%, 111.8%, and 98.6% compared to the intact model at C3–C4, C4–C5, and C5–C6, respectively. The ROM in laminoplasty-res further increased by 105.2%, 116.8%, and 101.8% compared to the intact model at C3–C4, C4–C5, and C5–C6, respectively. The maximum stress in the annulus/nucleus was observed under left bending at the C4–C5 segment where an increase of 139.5% and 229.6% compared to the intact model was observed for laminoplasty-pre and laminoplasty-res model, respectively. The highest facet contact forces were observed at C4–C5 under axial rotation, where an increase of 500.7% and 500.7% was observed compared to the intact model for laminoplasty-pre and laminoplasty-res, respectively. The posterior ligaments of the cervical spine play a vital role in restoring/stabilizing the cervical spine. When laminoplasty is performed, the surgeon needs to be careful not to injure the posterior soft tissue, including ligaments such as LF.

Global Spinal Alignment in Patients With Cervical Spondylotic Myelopathy

STUDY DESIGN

A prospective radiographic analysis of cervical spondylotic myelopathy (CSM).

OBJECTIVE

The aim of this study was to clarify the pathophysiology of CSM, and use the characteristic of global spinal alignment for determining the surgical strategy.

SUMMARY OF BACKGROUND DATA

Radiographic evaluation of CSM, in general, comprises cervical magnetic resonance imaging (MRI) and regional cervical radiography, which cannot distinguish between cervical hyperlodorsis with spinopelvic compensation and cervical lordorsis with normal global alignment.

METHODS

Our inclusion criteria were preoperative whole spine radiography and cervical MRI and health-related quality of life scores. Global spinal alignment was characterized by cervical lordosis (CL), C7 sagittal vertical axis (SVA), T1 slope (T1S), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and knee flexion angle (KFA). Cervical alignment was characterized by O-C2, C2-4, C5-7, and C2-7 angles; cranial center of gravity (CCG) C7SVA; and C2-7 SVA. Responsible lesion determined using MRI was divided from C2/3 to C7/T1.

RESULTS

Eighty-eight surgically treated CSM patients with EOS full spine imaging were prospectively analyzed. There were 72 normal (Type 1; SVA <50 mm) and 16 positive (Type 2; SVA ≥50 mm) global balance patients. There were significant differences in age, T1S, KFA, T1S-CL, SVA, CCG-SVA, and C2-7 SVA between Type 1 and Type 2. C3/4 lesion was more common in Type 2 than in Type 1. There was a positive correlation between global sagittal, but not regional, balance, and responsible lesion. C3/4 lesion was more frequent in older, male, high SVA, large T1S-CL, large KFA, and large cranial lordosis (C2-4/C5-7 angle) patients.

CONCLUSION

This study indicates the necessity for global alignment evaluation, particularly in older CSM patients because of their compensation mechanism for global malalignment. Surgical strategy for cranial type CSM should be carefully selected considering global balance.

LEVEL OF EVIDENCE

4.

Clinical Characteristics and Management of C3-4 Degenerative Cervical Myelopathy

Single-level anterior cervical discectomy and fusion (ACDF) was performed at C3-4; non-C3-4 ACDF patients of the authors' random sample of ACDF patients were compared with C3-4 ACDF patients. The radiological study of C3-4 ACDF patients shows that they had significant cervical lordosis, and cervical motion was dependent on the C3-4 segment, which accounted for 39.8% of C2-7 range of intervertebral motion (total motion). In C3-4 ACDF patients, not only static factors but also dynamic factors (instability) at the C3-4 level contributed to the major causes of degenerative cervical myelopathy.

Surgical Outcome of Laminoplasty for Cervical Spondylotic Myelopathy in an Elderly Population - Potentiality for Effective Early Surgical Intervention: A Meta-analysis

A systematic review and meta-analysis was conducted to determine differences in surgical outcomes of laminoplasty for cervical spondylotic myelopathy (CSM) between elderly and non-elderly patients. PubMed and Google Scholar searches were performed using several key words and phrases related to cervical laminoplasty in elderly populations. Included studies were written in English, addressed laminoplasty for cervical spondylotic myelopathy, and evaluated outcomes of the treatment. Statistical analysis was performed using a random-effect model. The heterogeneity of the studies was assessed using Cochran's Q statistic and I² statistic, and a funnel plot was constructed to evaluate publication bias. The search initially identified 255 articles on this topic. Nine clinical studies that met all inclusion criteria were included in the meta-analysis. A total of 1817 patients in these studies underwent cervical laminoplasty. Elderly patients had lower preoperative and postoperative Japanese Orthopedic Association (JOA) scores, and lower recovery rates based on JOA scores. Shorter operation times and reductions in intraoperative blood loss were found in the elderly group compared to the non-elderly group. The incidence of C5 palsy was not different between these groups. We here report the differences in surgical outcomes of laminoplasty for CSM through systematic review and meta-analysis. This report found poor surgical outcomes and lower preoperative JOA scores in elderly patients. Therefore, early surgical intervention may be recommended in elderly patients with CSM.

Effect of correction surgery for cervical kyphosis on compensatory mechanisms in overall spinopelvic sagittal alignment

PURPOSE

Progression of kyphotic deformity at the middle/lower cervical spine can cause difficulty with horizontal gaze, so compensation at other spinopelvic parts may occur. However, the precise mechanism remains unclear. The present study investigated the effect of correction surgery for cervical kyphosis on the compensatory mechanisms in overall spinopelvic sagittal alignment.

METHODS

Forty-one patients, comprising 23 males and 18 females (mean age 67 years), underwent correction surgery for cervical kyphosis using the posterior screw-rod system. Spinopelvic lateral radiographs in the standing position were taken before and after surgery. C0-1 angle, C1-2 angle, clivo-axial angle (CAA), C2-7 angle, thoracic kyphosis, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope were measured. Correlations between C2-7 angle and these parameters before surgery, and correlations between the correction angle of cervical kyphosis and postoperative changes of these parameters were evaluated.

RESULTS

Negative correlations were found between the C2-7 angle and CAA (R = -0.640, p < 0.01), and C2-7 angle and C0-1 angle (R = -0.762, p < 0.001) before surgery. Negative correlations were found between the correction angle of C2-7 and change of CAA (R = -0.718, p < 0.001), and between the correction angle of C2-7 and change of C0-1 angle (R = -0.672, p < 0.01) after surgery.

CONCLUSIONS

The present study demonstrated that C0-1 angle and CAA are more important in the compensatory mechanism for kyphotic deformity at the middle/lower cervical spine compared to downward parameters. That is, to maintain horizontal gaze, lordosis increases at the cranio-cervical junction with greater kyphosis at the middle/lower cervical spine. Correction of cervical kyphosis in the middle/lower cervical spine resulted in normalization of the C0-1 angle and CAA because the compensatory mechanism at the cranio-cervical junction for obtaining horizontal gaze was no longer necessary after surgical intervention.

Anterior Cervical Discectomy and Fusion Provides Better Surgical Outcomes Than Posterior Laminoplasty in Elderly Patients With C3-4 Level Myelopathy

STUDY DESIGN

Retrospective analyses of prospectively collected data regarding 180 patients with cervical spondylotic myelopathy (CSM).

OBJECTIVE

To detect the characteristics of C3-4 level CSM in elderly patients (C3-4CSM) (main analysis) and to validate the postoperative outcomes of anterior cervical discectomy and fusion (ACDF) and of laminoplasty (LAMP) (subgroup analysis).

SUMMARY OF BACKGROUND DATA

It remains unclear which surgical technique offers the best outcomes for CSM.

METHODS

The main analysis included 180 patients with CSM, divided into two groups (C3-4CSM group, n = 46; conventional CSM group, n = 134) according to the findings of the preoperative physical examination and magnetic resonance imaging. The subgroup analysis included 46 patients with C3-4CSM, divided into two groups (ACDF group, n = 21; LAMP group, n = 25) according to surgical technique. Preoperative demographics and postoperative outcomes were compared.

RESULTS

The age at surgery was higher, disease duration was shorter, and preoperative Japanese Orthopaedic Association (JOA) score was lower in the C3-4CSM group than in the conventional CSM group. Although the C3-4 range of motion was significantly higher, that of other levels was significantly lower in the C3-4CSM group. The anteroposterior diameter for levels C3-C7 was significantly larger in the C3-4CSM group. In the subgroup analysis using the repeated-measures analysis of variance, the postoperative JOA scores, and visual analog scale of neck pain were significantly better in the ACDF group.

CONCLUSION

Higher age, shorter disease duration, and worse JOA scores appear to be characteristic of C3-4CSM. In the management of C3-4CSM, ACDF provided better surgical outcomes than did LAMP; hypermobility at the C3-4 level, a radiological characteristic of C3-4CSM, may be one of key factors affecting surgical outcome. The chance to diagnose C3-4CSM is increasing with the increasing healthy life expectancy. To enable effective resolution of symptoms, C3-4CSM must be distinguished from conventional CSM.

LEVEL OF EVIDENCE

4.

Radiological study of C3-C4 level surgical cases of cervical spondylosis

Objective:

The purpose of this study was to elucidate the pathological characteristics of C3-C4 cervical spondylotic myelopathy (CSM) from the radiological study.

Materials and Methods:

A total of 31 patients with single level anterior cervical discectomy and fusion (ACDF) at C3-C4 and 46 patients with single level ACDF at C5-C6 were included in this study. We selected C5-C6 level as a representative of the lower cervical level. The C3-C4 and C5-C6 levels were routinely examined to investigate the areas of the vertebral canal, subarachnoid space, and spinal cord in the cervical canal.

Results:

The clinical study of C3-C4 ACDF patients showed that as for the C3-C4 area, the area of the cervical vertebral canal, the area of the subarachnoid space, and he transverse surface area of the spinal cord were all significantly smaller in C3-C4 ACDF patients than in C5-C6 ACDF patients. Moreover, as for the C5-C6 area, only the area of the subarachnoid space was significantly smaller in C5-C6 ACDF patients than in C3-C4 ACDF patients. Spondylotic changes predominated at both the C3-C4 and C5-C6 levels. However, in the C5-C6 ACDF patients, spondylotic changes tended to predominate only at the operation level at C5-C6.

Conclusions:

Aging process develops from lower cervical to upper cervical level. Moreover, this static factor in conjunction with dynamic factor (instability) was the causative factors for the CSM in C3-C4 ACDF patients.

Clinical study of C3-C4 level surgical cases of cervical spondylosis

OBJECTIVE

The purpose of this study was to elucidate the pathological characteristics of C3-C4 cervical spondylotic myelopathy (CSM).

METHODS

Single-level anterior cervical discectomy and fusion (ACDF) was performed at C3-C4 in 53 patients (38 men, 15 women). The mean duration of preoperative symptoms was 6.0 months. Fifty-three non C3-C4 ACDF patients of our random sample of ACDF patients were compared to the C3-C4 ACDF patients. Clinical outcomes were assessed according to the Japanese Orthopedic Association score (JOA score), the Neurosurgical Cervical Spine Scale (NCSS), and the Nurick scale. And radiological findings including C2-C7 lordosis, C3-C4 range of intervertebral motion (ROM), C2-C7 ROM, and C3-C4%ROM in the cervical spine were evaluated in both groups.

RESULTS

The recovery rates of JOA score and the NCSS in C3-C4 ACDF patients were 62.5% and 62.1%, respectively. The radiological study of C3-C4 ACDF patients showed that they had significant cervical lordosis, and cervical motion was dependent on the C3-C4 segment, which accounted for 39.8% of C2-C7 ROM (total motion).

CONCLUSION

In C3-C4 ACDF patients, not only static factors, but dynamic factors (instability) at the C3-C4 level contributed to the major causes of CSM.

[Diagnosis and management of cervical spondylosis]

Cervical spondylosis, which can present as radiculopathy and myelopathy, is common in people over the age of 50. Since evidence of radiological spondylotic change is frequently found in many asymptomatic adults, it is necessary to assess whether neurological symptoms result from cervical spondylosis or other neurological disorders. In order to avoid misdiagnosis, it is important to compare the levels of the lesions shown on imaging with the clinical findings. Differential diagnosis between amyotrophic lateral sclerosis and cervical spondylotic myelopathy is an issue of major clinical importance. Though the course of disease development and the ultimate prognosis for patients with cervical spondylosis is highly variable and extremely difficult to predict, many patients experience a relatively benign form of the disease.

The effects of surgery on locomotion in elderly patients with cervical spondylotic myelopathy

PURPOSE

This study aimed to evaluate the effects of surgery on locomotor ability in patients with cervical spondylotic myelopathy (CSM) and compare the results between elderly and younger patients.

METHODS

A total of 369 consecutive patients who underwent expansive laminoplasty for CSM were prospectively analysed. Patients were divided into two age groups of ≥ 75 years (elderly group, 76 patients) and <75 years (younger group, 293 patients). Locomotor ability was estimated using part of the functional independence measure (FIM). The sum of gait and stairs items [functional independence measure (locomotion), FIM-L; possible scores, 2-14] and neurological status were estimated using the Japanese Orthopaedic Association (JOA) score (possible score, 0-17). Pre-operative neurological anamnesis was reviewed, and the surgical results of elderly patients with or without co-existing neurological history were evaluated to determine the origin of locomotor disability.

RESULTS

Peri-operative FIM-L and JOA scores were significantly lower in the elderly group than in the younger group, and the opposite was true for improved FIM score. Cerebral infarction and previous lumbar surgery were identified as neurological co-morbidities in the elderly group. However, there was no significant difference in surgical results between elderly patients with and without co-existing neurological disorders.

CONCLUSIONS

Decompression surgery can improve locomotor ability and decrease nursing care requirements among elderly patients with CSM. However, other neurological diseases can co-exist in elderly patients, making it difficult to diagnose the origin of locomotor disability. Therefore, detailed peri-operative work-up and timely decompression should be given priority to avoid progression towards fixed locomotor disability.

Cardiopulmonary function in elderly patients with cervical spondylotic myelopathy

BACKGROUND

Most elderly patients have cardiopulmonary diseases anamnesis and a perceived risk of perioperative complications. The responsible lesion may be located more cranially in elderly patients with cervical spondylotic myelopathy (CSM) compared with that in younger patients. The study aimed at evaluating cardiopulmonary dysfunction of CSM and effects of surgery on cardiopulmonary function and perioperative complications.

METHODS

Thirty-one consecutive patients (>75 years of age) who underwent expansive laminoplasty for CSM were compared with 30 age-matched controls who underwent lumbar decompression. The ejection fraction (EF), percent vital capacity (%VC), and forced expiratory volume percent in 1 s (FEV(1)%) before and 6 months after surgery were analyzed by cardiac ultrasonography and spirometry. Furthermore, neurological status, lesion level, and perioperative complications were evaluated.

RESULTS

The mean %VC significantly decreased in the study group compared with that in the control group before surgery (89.4 ± 12.4 vs. 96.5 ± 12.7, P = 0.032). EF, %VC, and FEV(1)% showed no significant differences after surgery. The mean %VC was significantly lower in the cranial group with lesions above C4 compared with that in the caudal group before (81.8 ± 10.0 vs. 95.0 ± 11.2, P = 0.0021) and after (83.8 ± 9.7 vs. 92.1 ± 11.8, P = 0.047) surgery. The Japanese Orthopaedic Association score significantly improved after surgery (P < 0.001), and the mean recovery rate was 48.3%. The occurrence of perioperative complications was significantly higher in the study group compared with that in the control group (P = 0.018).

CONCLUSIONS

Elderly CSM patients with cranial lesions have a decreased %VC and high risk of perioperative cardiopulmonary complications. Therefore, detailed perioperative workup and timely decompression should be performed to avoid progression toward fixed neurological deficits and cardiopulmonary dysfunction whether or not they result from myelopathy itself.

Cervical spinal canal stenosis: the differences between stenosis at the lower cervical and multiple segment levels

The lower cervical segments are commonly the level responsible for cervical spondylotic myelopathy; however, we rarely encounter stenosis at the upper cervical segment in a clinical setting. We assumed that there might be some differences between the pathogenetic mechanisms underlying the development of cervical canal stenosis at different segments. We performed positional MRI in the weight-bearing position for 295 consecutive symptomatic patients. All subjects were classified into four groups (A: normal; B: C3-4 stenosis; C: C5-6 stenosis; D: two-level cervical segments stenosis, stenosis at C3-4 and C5-6). Age, sagittal cervical canal diameter, cervical intervertebral disc degeneration, cervical cord compression, and cervical mobilities were evaluated for each group. Group B showed a narrow cervical spinal canal structure at the C3 to C4 pedicle levels, while groups C and D showed narrow structures at the C4 to C6 pedicle levels in the cervical spine. Additionally, the sagittal cervical canal diameters at all pedicle levels, except C7, in group D were significantly smaller than those observed in group C. We demonstrated the differences in the pathogenetic processes for the development of cervical spinal canal stenosis between C3-4, C5-6, and two-level cervical segments stenosis. Our results suggest that the developmental morphological structure of the cervical spinal canal plays an important role in the development of cervical canal stenosis at different segments. Moreover, individuals with sagittal cervical canal diameters of less than 13 mm may be exposed to an increased risk for future development of cervical spinal canal stenosis at the upper cervical segments following stenosis at the lower cervical segments.

Anterior spinal fusion versus laminoplasty for cervical spondylotic myelopathy: a retrospective review

PURPOSE

To compare outcomes of anterior spinal fusion (ASF) versus laminoplasty for cervical spondylotic myelopathy (CSM).

METHODS

Records of 26 women and 37 men aged 34 to 83 (mean, 67) years who underwent ASF or laminoplasty for CSM were reviewed. Patient demographics, duration of symptoms, pre- and post-operative Japanese Orthopaedic Association (JOA) scores, Hirabayashi recovery rate, and radiographic features (including anteroposterior canal diameter, Pavlov ratio, and number of levels compressed) were compared.

RESULTS

The mean duration of symptoms was 9 months. The mean follow-up period was 40 months. Patients who underwent laminoplasty were older (p=0.015) and had more levels compressed (p<0.001) than those who underwent ASF. Patients with C3/4 compression were older than those without it (p=0.044). Younger patients had higher Hirabayashi recovery rate (p=0.043).

CONCLUSION

The surgical decision for ASF or laminoplasty mainly depends on the number of levels compressed and patient age. Laminoplasty is usually reserved for older patients with multiple level involvement. Age is the main predictive factor for surgical outcome.

Expansive laminoplasty for cervical myelopathy with interconnected porous calcium hydroxyapatite ceramic spacers: comparison with autogenous bone spacers

STUDY DESIGN

Expansive cervical laminoplasties with interconnected porous calcium hydroxyapatite ceramic (IP-CHA) spacers were performed in cervical myelopathy patients.

OBJECTIVES

To evaluate the usefulness and osteoconductive capability of IP-CHA spacers in expansive laminoplasty.

SUMMARY OF BACKGROUND DATA

Expansive laminoplasty for cervical myelopathy is designed to preserve the posterior structures, so as to prevent postoperative development of instability and cervical kyphosis. The technique requires successful reconstruction of the laminae of vertebral arches, as sinking or nonunion of the expanded laminae may induce neurologic regression, segmental motor paralysis, and postoperative axial pain. A novel IP-CHA with sufficient biocompatibility and mechanical strength was developed as an artificial bone substitute.

METHODS

Expansive open-door laminoplasties were performed in 88 cervical myelopathy patients, and both autogenous bone spacers harvested from the spinous processes and IP-CHA spacers in combination with bone marrow were alternately grafted into the opened side of each lamina. All patients were followed up with computerized tomography scans, and bonding rates for both the IP-CHA and autogenous spacers, bone fusion rates of the hinges of the laminae, and complications associated with the implants were examined.

RESULTS

Clinical symptoms significantly improved in all patients without major complications related to the procedure. The IP-CHA spacers demonstrated comparable bone bonding to the autogenous spacers on postoperative computerized tomography scans. The expanded laminae withstood expanded positions without sinking or floating throughout the followups, and the hinges completely fused in more than 95% of patients in both groups within 1 year.

CONCLUSIONS

The IP-CHA spacer contributed to high bone fusion rates of the spacers and hinges of the laminae, and there were no complications associated with their use. Cervical laminoplasty with the IP-CHA spacers is a safe and simple method that yields sufficient fixation strength and provides sufficient bone bonding within a short period of time after operation.

The effects of the degenerative changes in the functional spinal unit on the kinematics of the cervical spine

STUDY DESIGN

The sagittal kinematics of the cervical spine was evaluated using kinematic magnetic resonance imaging (kMRI).

OBJECTIVE

To investigate the effect of degenerative changes in the functional spinal unit on cervical kinematics by using kMRI.

SUMMARY OF BACKGROUND DATA

Few studies have, thus far, by using MR images, described the contribution of degenerative changes in the functional spinal unit to cervical kinematics; however, the exact cervical kinematics remains uncertain.

METHODS

A total of 289 consecutive symptomatic patients underwent dynamic cervical MRI in flexion, neutral, and extension postures. All digital measurements and calculations of the variations in segmental angular motion were automatically performed by an MR analyzer using true MR images with 77 predetermined points marked on each image. Each segment was assessed based on the extent of intervertebral disc degeneration (Grades 1-3) and cervical cord compression (groups A-C) observed on T2-weighted MR images.

RESULTS

The segmental mobility of the segments with severe cord compression and moderate disc degeneration tended to be lower than that of the segments with severe cord compression and severe disc degeneration, and a significant difference was observed in the segmental mobility of the C5-C6 segment. Moreover, in all segments with moderate disc degeneration, the segmental mobility was significantly reduced in the presence of severe cord compression, as compared with no compression. However, in segments with severe disc degeneration, no significant differences were observed between the segmental mobility of the cord compression groups.

CONCLUSION

Our results suggest that cervical cord compression may cause deterioration of cervical cord function and kinematic changes in the cervical spine. We hypothesize that the spinal cord may potentially protect its functions from dynamic mechanical cord compression by restricting segmental motion, and these mechanisms may be closely related to the intervertebral discs.

Anterolisthesis and retrolisthesis of the cervical spine in cervical spondylotic myelopathy in the elderly

BACKGROUND

Degenerative spondylolisthesis of the cervical spine has received insufficient attention in contrast to that of the lumbar spine. The authors analyzed the functional significance of anterior and posterior degenerative spondylolisthesis (anterolisthesis and retrolisthesis) of the cervical spine to elucidate its role in the development of cervical spondylotic myelopathy (CSM) in the elderly.

METHODS

A total of 79 patients aged 65 or older who eventually had surgical treatment for CSM were evaluated radiographically.

RESULTS

Altogether, 24 patients (30%) had displacement of 3.5 mm or more (severe spondylolisthesis group), 31 had displacement of 2.0-3.4 mm (moderate spondylolisthesis group), and 24 had less than 2.0 mm displacement (mild spondylolisthesis group). The severe spondylolisthesis group consisted of 14 patients with anterolisthesis (anterolisthesis group) and 10 patients with retrolisthesis (retrolisthesis group). Patients with severe spondylolisthesis had a high incidence (93%) of degenerative spondylolisthesis at C3/4 or C4/5 and significantly greater cervical mobility than those with mild spondylolisthesis. The anterolisthesis group, but not the retrolisthesis group, had a significantly wider spinal canal than the mild spondylolisthesis group, although the degree of horizontal displacement and cervical mobility did not differ significantly between the anterolisthesis and retrolisthesis groups. Severe cord compression seen on T1-weighted magnetic resonance imaging (MRI) scans and high-intensity spinal cord signals seen on T2-weighted MRI scans corresponded significantly to the levels of the spondylolisthesis.

CONCLUSIONS

Degenerative spondylolisthesis is not a rare radiographic finding in elderly patients with CSM, which tends to cause intense cord compression that is seen on MRI scans. Greater mobility of the upper cervical segments may be a compensatory reaction for advanced disc degeneration of the lower cervical segments, leading to the development of degenerative spondylolisthesis. With a similar degree of displacement, anterolisthesis tends to have a greater impact on the development of CSM than retrolisthesis.

Diagnosis and management of cervicogenic headache

Upper cervical pain and/or headaches originating from the C0 to C3 segments are pain-states that are commonly encountered in the clinic. The upper cervical spine anatomically and biomechanically differs from the lower cervical spine. Patients with upper cervical disorders fall into two clinical groups: (1) local cervical syndrome; and (2) cervicocephalic syndrome. Symptoms associated with various forms of both disorders often overlap, making diagnosis a great challenge. The recognition and categorization of specific provocation and limitation patterns lend to effective and accurate diagnosis of local cervical and cervicocephalic conditions.

The assessment of cervical myelopathy

The assessment of cervical myelopathy can be challenging, especially early in the course of the disease. Typical symptoms, including pain, neck stiffness, paresthesias, weakness, clumsiness, disequilibrium, difficulty with bladder control and functional deficits, and signs, including decreased cervical range of motion, sensory abnormalities, weakness, spasticity, and gait disturbance, become more obvious as the disease progresses. Disease specific functional assessments can aid in the diagnosis. A detailed clinical assessment should always be interpreted in conjunction with supplemental assessment tools, including imaging and electrodiagnostic studies. This article will review typical clinical findings, the differential diagnosis, and the utilization of supplemental assessment tools for the evaluation of cervical myelopathy.

Pathophysiology of cervical myelopathy

BACKGROUND CONTENT

Cervical myelopathy is a group of closely related disorders usually caused by spondylosis or by ossification of the posterior longitudinal ligament and is characterized by compression of the cervical spinal cord or nerve roots by varying degrees and number of levels. The decrease in diameter of the vertebral canal secondary to disc degeneration and osteophytic spurs compresses the spinal cord and nerve roots at one or several levels, producing direct damage and often secondary ischemic changes.

PURPOSE

Clinicians who treat cervical myelopathy cord injuries should have a basic understanding of the pathophysiology and the processes that are initiated after the spinal cord has been injured.

STUDY DESIGN/SETTING

Literature review.

METHODS

Literature review of human cervical myelopathy and clinically relevant animal models to further our understanding of the pathological mechanisms involved.

RESULTS

The pathophysiology of cervical myelopathy involves static factors, which result in acquired or developmental stenosis of the cervical canal and dynamic factors, which involve repetitive injury to the cervical cord. These mechanical factors in turn result in direct injury to neurons and glia as well as a secondary cascade of events including ischemia, excitotoxicity, and apoptosis; a pathobiology similar to that occurring in traumatic spinal cord injury.

CONCLUSIONS

This review summarizes some of the significant pathophysiological processes involved in cervical myelopathy.

Clinical features and surgical outcomes of cervical myelopathy in the elderly

Treatment of cervical myelopathy in elderly patients is controversial. We retrospectively studied 113 patients who had decompression surgery from 1990-2001 to clarify how pre-operative conditions, duration of symptoms, involved levels, surgical outcomes, and complications differ between younger and elderly patients. We also asked whether elderly patients would likely have reasonable outcomes of surgery. The patients were divided into five age groups: Group 1, 36-45 years (12 patients); Group 2, 46-55 years (22 patients); Group 3, 56-65 years (31 patients); Group 4, 66-75 years (32 patients); and Group 5, 76-85 years (16 patients). The duration of symptoms was similar among the five groups. The involved level was more cephalic in the older groups, and the most frequently involved level in patients older than 75 years was C3-C4. Neurologic symptoms were more severe preoperatively and postoperatively in older patients. The recovery ratio also was lower in older patients; however, in Group 5 it was 36.9%, which indicated that patients older than 75 years could regain approximately 40% of their function postoperatively. Decompression surgery can be a reasonable treatment option for cervical myelopathy, even in elderly patients.

LEVEL OF EVIDENCE

Therapeutic Study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Functional diagnosis using multimodal spinal cord evoked potentials in cervical myelopathy

The electrophysiological measurement of spinal cord evoked potentials (SCEPs) has been established as a tool for diagnosing the spinal level responsible for cervical myelopathy. Only a few studies, however, employed multimodal SCEPs for this purpose. The objective of this study was to investigate the correlation between multimodal SCEPs recorded during cervical laminoplasty and magnetic resonance imaging (MRI) abnormalities in 18 patients aged 70 years and older versus 32 patients less than 65 years of age. Both the SCEPs and MRIs showed higher incidences of multiple-level cord involvement in the older group than in the younger group. Discrepancies in the spinal levels involved between the SCEPs and the MRIs were found in 12 patients (67%) for the older group and 6 patients (19%) for the younger group. The accuracy of the MR images in localizing the lesion site was significantly lower in the older group than in the younger group, indicating that MR images tend to show clinically silent cord compression in elderly patients. Because spinal cord compression can appear without functional change in elderly patients, electrophysiological evaluations with intraoperative multimodal SCEP studies are a useful addition to MRI for understanding the pathology of myelopathy.

Segmental degeneration in the cervical spine and associated changes in dorsal root ganglia

Degenerative change in cervical segments C5-C7 was documented to determine whether osteo-ligamentous adaptations were age-related. In addition, companion morphological studies were carried out to determine whether parallel changes occurred in related soft tissues, including DRG. Independent of the provoking stimulus, aberrant soft tissue change may be expected with segmental degeneration. Two associations were identified: between the incidence of segmental degeneration and severity of DRG distortion, and between segmental degeneration and DRG inflammatory mast cell density. Peripheral type C cells seemed more susceptible to compression in circumstances of DRG distortion. In light of neuropeptide expression in these cell types, predominant type C cell compression may be clinically relevant in the noxious cascade contributing to the sensation of pain.

Functional importance of degenerative spondylolisthesis in cervical spondylotic myelopathy in the elderly

STUDY DESIGN

A correlation was studied between degenerative spondylolisthesis (DSL) of the cervical spine and spinal-evoked potentials intraoperatively recorded in elderly patients who had surgical treatment for cervical spondylotic myelopathy.

OBJECTIVE

To investigate the functional importance of cervical DSL in elderly patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

Cervical DSL has received insufficient attention in contrast to the lumbar DSL. The authors are unaware of any journal article in which this condition has been evaluated electrophysiologically.

METHODS

This study investigated 47 patients with 68 DSL of 2 mm or more (3.1 +/- 0.9 mm; range, 2-6 mm) who underwent serial intervertebral recording of spinal-evoked potentials from either the intervertebral disc or the ligamentum flavum after epidural stimulation.

RESULTS

All the study patients had unequivocal evidence of a focal conduction block, with the area of negative evoked potential peak reduced to less than 60% that of the immediately caudal level: 31 at C3-C4, 12 at C4-C5, and 1 each at C1-C2, C2-C3, C5-C6, and C6-C7. The site of conduction block matched the level of DSL in 30 patients, but not in 17 patients. The DSL accompanied by conduction block had significantly greater displacement with greater angular mobility than that without conduction block.

CONCLUSIONS

A significant association between DSL and conduction block in the face of a relatively wide canal indicates the functional importance of DSL in elderly patients with cervical spondylotic myelopathy. In this age group, a high incidence of both DSL (81%) and focal conduction block (91%) at the upper cervical level (C3-C4 or C4-C5) is of clinical interest.