Predictability of operative results of cervical compression myelopathy based on preoperative computed tomographic myelography

Anterior cervical discectomy fusion versus posterior decompression and fusion in octogenarians with cervical myelopathy: Clinical outcomes and complications with a 3-year follow-up

Introduction

Cervical stenosis and concurrent Cervical Spondylotic Myelopathy (CSM) are prevalent in the elderly. Treatment options include Anterior Cervical Discectomy Fusion (ACDF) and Posterior Decompression and Fusion (PDF).

Research question

This study aims to compare clinical outcomes and complications between ACDF and PDF in patients aged 80 and above.

Material and methods

Data from electronic medical records between 2005 and 2021 at a single institution were analyzed. Logistic and linear regression analyses were performed to explore risk factors and the relationship between comorbidities and neurological conditions.

Results

21 patients with ACDF and 26 with PDF were studied over 16 years. PDF patients had more operated levels, higher blood loss, and longer hospital stays, but mortality rates and mJOA improvements were similar in both groups. The presence of comorbidities was a unique risk factor for postoperative complications.

Discussion and conclusion

ACDF and PDF led to neurological improvements in elderly CSM patients. However, the decision of surgical procedure should carefully consider the potential for postoperative complications, particularly in patients with comorbidities.

Role of preoperative cervical alignment on postoperative dysphagia after occipitocervical fusion

Background:

Dysphagia is one of the most serious complications of occipitocervical fusion (OCF). The previous studies have shown that postoperative cervical alignment, documented with occipito (O)-C2 angles, C2-C6 angles, and pharyngeal inlet angles (PIA), impacted the incidence of postoperative dysphagia in patients undergoing OCF. Here, we investigated the relationship of preoperative versus postoperative cervical alignment on the incidence of postoperative dysphagia after OCF.

Methods:

We retrospectively reviewed the clinical data/medical charts for 22 patients following OCF (2006– 2019). The O-C2 angles, C2-C6 angles, PIA, and narrowest pharyngeal airway spaces (nPAS) were assessed using plain lateral radiographs of the cervical spine before and after the surgery. The severity of dysphagia was assessed with the functional oral intake scale (FOIS) levels as documented in medical charts; based on this, patients were classified into the nondysphagia (FOIS: 7) versus dysphagia (FOIS: 1–6) groups.

Results:

Seven patients (35%) experienced dysphagia after OCF surgery. Preoperative PIA and nPAS were smaller in the dysphagia group. Spearman rank correlation showed a positive correlation between preoperative PIA and FOIS and between preoperative nPAS and FOIS.

Conclusion:

This study suggests that preoperative cervical alignment may best predict the incidence of postoperative dysphagia after OCF.

Relationship between cervical muscle morphology evaluated by MRI, cervical muscle strength and functional outcomes in patients with degenerative cervical myelopathy

BACKGROUND

Cervical muscle alterations have been reported in patients with chronic neck pain, but the assessment of muscle morphology and strength has been overlooked in patients with degenerative cervical myelopathy (DCM).

OBJECTIVES

This study aimed to investigate the relationship between cervical muscle degenerative changes observed on MRI, muscle strength and symptoms severity in patients diagnosed with DCM.

DESIGN

Observational study.

METHODS

Cervical muscle measurements of total cross-sectional area (CSA), functional CSA (fat free area, FCSA) and ratio of FCSA/CSA (e.g. fatty infiltration) were obtained from T2-weighted axial MR images from C2-C3 to C6-C7 in 20 patients. Muscle strength was assessed manually using a microFET2 dynamometer. The association between cervical muscle morphology parameters, muscle strength, symptoms severity and functional status was investigated.

RESULTS

Greater mean CSA and FCSA was associated with greater overall muscle strength. The mean FCSA explained 37%, 76%, 39%, 20% and 65% of the total variance in flexion, extension, right-side bending, left-side bending and overall muscle strength, respectively. The mean ratio of FCSA/CSA was not significantly associated with cervical muscle strength in any direction. However, greater FCSA/CSA ratio (e.g. less fatty infiltration) was associated with lower disability score (p = 0.02, R² = 0.20).

CONCLUSIONS

Cervical muscle lean muscle mass was positively associated with cervical muscle strength in patients with DCM. Moreover, greater fatty infiltration in the cervical extensor muscles was associated with lower functional score. Such findings suggest that clinicians should pay greater attention to cervical muscle morphology and function in patients with DCM.

Long-Term Sustainability of Functional Improvement Following Central Corpectomy for Cervical Spondylotic Myelopathy and Ossification of Posterior Longitudinal Ligament

STUDY DESIGN

Retrospective study.

OBJECTIVE

To examine predictors of long-term outcome and sustainability of initial functional improvement in patients undergoing corpectomy for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

There are limited data on the predictors of outcome and sustainability of initial functional improvement on long-term follow-up after cervical corpectomy.

METHODS

We studied the functional outcome at more than 1-year follow-up after central corpectomy in 352 patients with CSM or OPLL. Functional status was evaluated with the Nurick grading system. Analysis was directed at identifying factors associated with both improvement in functional status and the achievement of a "cure" (improvement to a follow-up Nurick grade of 0 or 1). A survival analysis was performed to identify factors associated with sustained functional improvement in patients with serial follow-up evaluations.

RESULTS

Nurick grade improved from 3.2 ± 0.1 to 1.9 ± 0.1 over a mean follow-up period of 57.1 months (range 12-228 mo). On multivariate analysis, age ≥50 years (P = 0.008) and symptom duration ≥1 year (P < 0.001) were negatively associated with functional improvement by ≥1 Nurick grade. Independent factors negatively associated with "cure" after surgery included age 50 years or older (P = 0.005), preoperative Nurick grade of 4 or higher (P < 0.001) and symptom duration of 1 or more years (P < 0.001). Early improvement in functional status was maintained in 90.5% and 76.3% of patients at 5 and 10 years follow-up, respectively. On survival analysis, patients with shorter preoperative symptom duration (<1 yr) were more likely to demonstrate sustained improvement in functional status after surgery (P = 0.022).

CONCLUSION

Initial gains in functional status after central corpectomy for CSM and OPLL are maintained in more than 75% of patients at 10 years after surgery. Overall, the most favorable long-term outcomes are achieved in younger patients who present early and with good preoperative functional status.

LEVEL OF EVIDENCE

4.

Incidence and risk factors of poor clinical outcomes in patients with cervical kyphosis after cervical surgery for spinal cord injury

Objective

This retrospective study investigated the incidence and risk factors of poor clinical outcomes after cervical surgery for cervical spinal cord injury in a large population of patients with global or segmental cervical kyphosis.

Methods

The clinical and radiological evaluation results of 269 patients with cervical kyphosis who underwent either anterior or posterior surgery between 2008 and 2013 were collected, preoperatively and at each follow-up after surgery.

Results

All patients were followed for an average of 2.5 years. Outcomes were classified as good or poor (n=156 and 113 patients, respectively), based on the Japanese Orthopedic Association (JOA) recovery ratios. The rates of patients with good or poor outcomes were statistically comparable with regard to gender ratio, type of injury, history of diabetes or cardiovascular disease, interval between injury and surgery, and follow-up time. The multivariate logistic regression analysis indicated that the following were independent predictors of poor improvement: patient age (P=0.016, odds ratio [OR] =1.0261); preoperative JOA scores (P=0.003, OR =0.1932); and cervical instability (P=0.004, OR =2.1562).

Conclusion

This study showed that advanced age, low preoperative JOA score, and cervical instability are closely associated with a poor surgical outcome in patients with cervical kyphosis. However, these results do not suggest that the type of cervical kyphosis influences the clinical outcome of surgery.

Preoperative Computed Tomography Myelography Parameters as Predictors of Outcome in Patients With Degenerative Cervical Myelopathy: Results of a Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

To determine the preoperative computed tomography (CT) myelogram imaging parameters in patients diagnosed with degenerative cervical myelopathy (DCM) that correlate with severity of DCM and predict postoperative patients' functional outcome.

METHODS

An electronic database search was performed using Ovid Medline and Embase. CT myelogram studies investigating the correlation between imaging characteristics and DCM severity or postoperative outcomes were included. Two independent reviewers performed citation screening, selection, qualitative assessment, and data extraction using an objective and blinded protocol.

RESULTS

A total of 5 studies (402 patients) were included in this review and investigated the role of preoperative CT myelogram parameters in predicting the functional outcome after surgical treatment of DCM. All studies were retrospective cohort studies. CT myelogram characteristics included the transverse area of the spinal cord at maximum level of compression, spinal canal narrowing, number of blocks, spinal canal diameter, and flattening ratio. There is low evidence suggesting that patients with a preoperative transverse area of the spinal cord >30 mm² at the level of maximum compression have better postoperative recovery and outcome. We found no studies investigating the correlation between preoperative CT myelogram parameters and DCM severity.

CONCLUSIONS

Patients with greater transverse area of spinal cord at the level of maximum compression on the preoperative CT myelogram are more likely to have better neurological outcome after surgery. There is insufficient evidence to suggest that any of the other CT myelogram parameters investigated are predictors of postoperative outcomes in patients with DCM.

Does age affect surgical outcomes in patients with degenerative cervical myelopathy? Results from the prospective multicenter AOSpine International study on 479 patients

BACKGROUND

In general, older patients with degenerative cervical myelopathy (DCM) are felt to have lower recovery potential following surgery due to increased degenerative pathology, comorbidities, reduced physiological reserves and age-related changes to the spinal cord. This study aims to determine whether age truly is an independent predictor of surgical outcome and to provide evidence to guide practice and decision-making.

METHODS

A total of 479 patients with DCM were prospectively enrolled in the CSM-International study at 16 centres. Our sample was divided into a younger group (<65 years) and an elderly (≥65 years) group. A mixed model analytic approach was used to evaluate differences in the modified Japanese Orthopaedic Association (mJOA), Nurick, Short Form-36 (SF-36) and Neck Disability Index (NDI) scores between groups. We first created an unadjusted model between age and surgical outcome and then developed two adjusted models that accounted for variations in (1) baseline characteristics and (2) both baseline and surgical factors.

RESULTS

Of the 479 patients, 360 (75.16%) were <65 years and 119 (24.84%) were ≥65 years. Elderly patients had a worse preoperative health status (p<0.0001) and were functionally more severe (p<0.0001). The majority of younger patients (64.96%) underwent anterior surgery, whereas the preferred approach in the elderly group was posterior (58.62%, p<0.0001). Elderly patients had a greater number of decompressed levels than younger patients (p<0.0001). At 24 months after surgery, younger patients achieved a higher postoperative mJOA (p<0.0001) and a lower Nurick score (p<0.0001) than elderly patients. After adjustments for patient and surgical characteristics, these differences in postoperative outcome scores decreased but remained significant.

CONCLUSIONS

Older age is an independent predictor of functional status in patients with DCM. However, patients over 65 with DCM still achieve functionally significant improvement after surgical decompression.

The value of preoperative magnetic resonance imaging in predicting postoperative recovery in patients with cervical spondylosis myelopathy: a meta-analysis

This meta-analysis was designed to elucidate whether preoperative signal intensity changes could predict the surgical outcomes of patients with cervical spondylosis myelopathy on the basis of T1-weighted and T2-weighted magnetic resonance imaging images. We searched the Medline database and the Cochrane Central Register of Controlled Trials for this purpose and 10 studies meeting our inclusion criteria were identified. In total, 650 cervical spondylosis myelopathy patients with (+) or without (-) intramedullary signal changes on their T2-weighted images were examined. Weighted mean differences and 95% confidence intervals were used to summarize the data. Patients with focal and faint border changes in the intramedullary signal on T2 magnetic resonance imaging had similar Japanese Orthopaedic Association recovery ratios as those with no signal changes on the magnetic resonance imaging images of the spinal cord did. The surgical outcomes were poorer in the patients with both T2 intramedullary signal changes, especially when the signal changes were multisegmental and had a well-defined border and T1 intramedullary signal changes compared with those without intramedullary signal changes. Preoperative magnetic resonance imaging including T1 and T2 imaging can thus be used to predict postoperative recovery in cervical spondylosis myelopathy patients.

Prognostic value of changes in spinal cord signal intensity on magnetic resonance imaging in patients with cervical compressive myelopathy

BACKGROUND CONTEXT

Signal intensity on preoperative cervical magnetic resonance imaging (MRI) of the spinal cord has been shown to be a potential predictor of outcome of surgery for cervical compressive myelopathy. However, the prognostic value of such signal remains controversial. One reason for the controversy is the lack of proper quantitative methods to assess MRI signal intensity.

PURPOSE

To quantify signal intensity and to correlate intramedullary signal changes on MRI T1- and T2-weighted images (WIs) with clinical outcome and prognosis.

STUDY DESIGN

Retrospective case study.

PATIENT SAMPLE

Patients (n=148; cervical spondylotic myelopathy, n=102 and ossified posterior longitudinal ligament, n=46) who underwent surgery for cervical compressive myelopathy and had high signal intensity change on sagittal T2-WI MRI before surgery between 2006 and 2010.

OUTCOME MEASURE

Neurologic assessment was conducted with the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. The rate of neurologic improvement was calculated with the use of preoperative and postoperative JOA scores.

METHODS

Quantitative analysis of MRI signal on both T1- and T2-WIs via use of the signal intensity ratio (SIR; signal intensity of lesion relative to that at C7-T1 disc level) was performed. Correlations between SIR on T1- and T2-WIs and preoperative JOA score, JOA improvement rate, disease duration, and MRI morphologic classification (cystic or diffuse type) were analyzed. Multivariate regression analysis for JOA improvement rate was also analyzed. In a substudy, 25 patients underwent follow-up MRI starting from 6 months after surgery to analyze the relationship between changes in SIR on follow-up MRI and clinical outcome.

RESULTS

SIR on T1-WIs, but not SIR on T2-WIs, correlated with postoperative neurologic improvement. The disease duration correlated negatively with SIR on T1-WIs and JOA improvement rate but not with SIR on T2-WIs. SIR on T2-WIs of "cystic type" was significantly greater than of "diffuse type," but SIR on T1-WI and JOA improvement rate were not different in the two types. Stepwise multivariate regression analysis indicated that SIR on T1-WIs and long disease duration were significant predictors of postoperative neurologic outcome. SIR on follow-up T1-WI and changes in SIR on T1-WI after surgery correlated positively with postoperative improvement rate. SIR on follow-up T2-WI and changes on T2-WI correlated negatively with postoperative neurologic improvement.

CONCLUSIONS

Our results suggest that low intensity signal on preoperative T1-WIs but not T2-WIs correlated with poor postoperative neurologic outcome. Furthermore, decreased signal intensity on postoperative T1-WIs and increased signal intensity on postoperative T2-WIs are predictors of poor neurologic outcome.

Evaluation of conservative treatment and timing of surgical intervention for mild forms of cervical spondylotic myelopathy

The optimal management approach for patients with mild forms of cervical spondylotic myelopathy (MCSM) has not been well established. The aim of the present study was to investigate the outcome of conservative treatment, identify prognostic factors and provide evidence for the timing of surgical intervention. A total of 90 patients with MCSM attending hospital between February 2007 and January 2009 were prospectively enrolled. Initially, all patients received conservative treatment and were followed up periodically. When a deterioration in myelopathy was clearly identified, surgical treatment was conducted. Clinical and radiological factors correlating with the deterioration were examined, and final clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) score. At the end of January 2012, follow-ups of >3 years were completed. Seventy-eight patients were available for data analysis. Only 21 patients (26.9%) deteriorated and underwent surgery thereafter (group A), while the remaining 57 patients (73.1%) were treated conservatively throughout (group B). Statistical analysis revealed that segmental instability and cervical spinal stenosis were adverse factors for the prognosis of conservative treatment. Although the JOA scores of the patients in group A declined initially, following surgical intervention, no significant differences were identified in JOA scores between the two groups at the time of the final follow-up (P=0.46). In summary, conservative treatment is effective in MCSM patients. Patients with segmental instability and cervical spinal stenosis have a tendency to deteriorate, but conservative treatment remains the recommendation for the first action. If the myelopathy deteriorates during conservative treatment, timely surgical intervention is effective.

Qualitative evidence from a systematic review of prognostic predictors for surgical outcomes following cervical ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament (OPLL) is a pathological ectopic ossification of this ligament that usually occurs in the cervical spine. For patients with cervical OPLL and neurological symptoms, surgical intervention is necessary but not always effective. Various prognostic factors influence the surgical outcome. The results of studies identifying these prognostic predictors are often inconclusive or contradictory. These predictors have not been well identified or summarized. The present study was designed to identify the prognostic predictors for the surgical outcome of cervical OPLL based on the available evidence in the literature. Non-interventional studies were searched in Medline, Embase, Science Direct, OVID and the Cochrane library. Forty-two observational studies involving 2791 patients were included. The quality of the included studies was assessed with a modified quality assessment tool, which was originally designed for use with observational studies. The effects of the studies were combined with the study quality score using a model of best-evidence synthesis. There was strong evidence for five predictors: (i) age, (ii) duration of symptoms, (iii) pre-operative neurological score, (iv) transverse area of the spinal cord, and (v) intramedullary high signal intensity on the T2-weighted MRI. We also identified eight predictors with moderate supporting evidence, seven with limited evidence, four with conflicting evidence and four predictors without supporting evidence. While there is no conclusive evidence regarding the surgical outcomes following cervical OPLL, these data provide evidence to guide the clinician in choosing an optimal therapeutic strategy for patients with cervical OPLL. Further research is necessary to fully evaluate the effects of the predictors described in this study.

Factors associated with intramedullary MRI abnormalities in patients with ossification of the posterior longitudinal ligament

STUDY DESIGN

A retrospective clinical study of 113 patients with ossification of the posterior longitudinal ligament (OPLL), who underwent either anterior or posterior surgery between 2006 and 2009.

OBJECTIVE

To evaluate the risk factors affecting the intramedullary spinal cord changes in signal intensity on magnetic resonance imaging (MRI) for the patients with OPLL.

SUMMARY OF BACKGROUND DATA

The relationship between the intramedullary spinal cord changes in signal intensity on MRI and neurological deficits, as well as the surgical outcomes, has been described. To obtain better prognosis, early surgery should be conducted in patients with OPLL who have potential abilities to develop intramedullary spinal cord changes in signal intensity on MRI. Various factors may be affecting the development of intramedullary spinal cord changes in signal intensity on MRI.

MATERIALS AND METHODS

The clinical and radiographic data of 113 patients with OPLL who underwent either anterior or posterior surgery between 2006 and 2009 were reviewed. Age, sex, complication, mean occupying ratio of OPLL (the greatest thickness of OPLL divided by the anteroposterior diameter of the bony spinal canal), duration of symptoms, type of OPLL, preoperative Japanese Orthopedic Association (JOA) score, and range of motion of the cervical spine were collected. Logistic regression analysis was used.

RESULTS

Changes in the intramedullary signal intensity on MRI were observed in 33 of the 113 patients. Statistical results show that duration of symptoms, occupying ratio of OPLL, preoperative JOA score, kyphosis, and instability of the cervical spine are the relevant risk factors for intramedullary spinal cord changes in signal intensity on MRI, with regression coefficients of 2.437, 0.953, -1.952, 2.093, and 1.516, respectively. For patients with OPLL, the longer the duration of the symptoms, or the higher occupying ratio of OPLL, or the lower preoperative JOA score, the greater the likelihood of intramedullary spinal cord changes in signal intensity on MRI.

CONCLUSIONS

As intramedullary spinal cord changes in signal intensity on MRI indicated severe damage to spinal cord and poor prognosis as we described before, early surgery is suggested for patients with OPLL who manifest one of the following factors: prolonged symptoms, high occupying ratio, low preoperative JOA score, kyphosis, or instability of the cervical spine. These factors are closely related to the intramedullary spinal cord changes in signal intensity on MRI.

MRI morphometric characterisation of the paediatric cervical spine and spinal cord in children with MPS IVA (Morquio-Brailsford syndrome)

Nearly all children with MPS IVA develop skeletal deformities affecting the spine. At the atlanto-axial spine, odontoid hypoplasia occurs. GAG deposition around the dens, leads to peri-odontoid infiltration. Transverse/alar ligament incompetence causes instability. Atlanto-axial instability is associated with cord compression and myelopathy, leading to major morbidity and mortality. Intervention is often required. Does the presence of widened bullet shaped vertebra in platyspondily encroach on the spinal canal and cause spinal stenosis in MPS IVA? So far, there have been no standardised morphometric measurements of the paediatric MPS IVA cervical spine to evaluate whether there is pre-existing spinal stenosis predisposing to compressive myelopathy or whether this is purely an acquired process secondary to instability and compression. This study provides the first radiological quantitative analysis of the cervical spine and spinal cord in a series of affected children. MRI morphometry indicates that the MPS IVA spine is narrower at C1-2 level giving an inverted funnel shape. There is no evidence of a reduction in the Torg ratio (canal-body ratio) in the cervical spine. The spinal canal does not exceed 11 mm at any level, significantly smaller than normal historical cohorts (14 mm). The sagittal diameter and axial surface area of both spinal canal and cord are reduced. C1-2 level cord compression was evident in the canal-cord ratio but the Torg ratio was not predictive of cord compression. In MPS IVA the reduction in the space available for the cord (SAC) is multifactorial rather than due to congenital spinal stenosis.

Predictors of outcome in patients with degenerative cervical spondylotic myelopathy undergoing surgical treatment: results of a systematic review

PURPOSE

To conduct a systematic review of the literature to determine important clinical predictors of surgical outcome in patients with cervical spondylotic myelopathy (CSM).

METHODS

A literature search was performed using MEDLINE, MEDLINE in Process, EMBASE and Cochrane Database of Systematic Reviews. Selected articles were evaluated using a 14-point modified SIGN scale and classified as either poor (<7), good (7-9) or excellent (10-14) quality of evidence. For each study, the association between various clinical factors and surgical outcome, evaluated by the (modified) Japanese Orthopaedic Association scale (mJOA/JOA), Nurick score or other measures, was defined. The results from the EXCELLENT studies were compared to the combined results from the EXCELLENT and GOOD studies which were compared to the results from all the studies.

RESULTS

The initial search yielded 1,677 citations. Ninety-one of these articles, including three translated from Japanese, met the inclusion and exclusion criteria and were graded. Of these, 16 were excellent, 38 were good and 37 were poor quality. Based on the excellent studies alone, a longer duration of symptoms was associated with a poorer outcome evaluated on both the mJOA/JOA scale and Nurick score. A more severe baseline score was related with a worse outcome only on the mJOA/JOA scale. Based on the GOOD and EXCELLENT studies, duration of symptoms and baseline severity score were consistent predictors of mJOA/JOA, but not Nurick. Age was an insignificant predictor of outcome on any of the functional outcomes considered.

CONCLUSION

The most important predictors of outcome were preoperative severity and duration of symptoms. This review also identified many other valuable predictors including signs, symptoms, comorbidities and smoking status.

Does the type of T2-weighted hyperintensity influence surgical outcome in patients with cervical spondylotic myelopathy? A review

PURPOSE

To review the literature on different classifications of T2-weighted (T2W) increased signal intensity (ISI) on preoperative magnetic resonance (MR) images of patients with cervical spondylotic myelopathy (CSM).

METHODS

The authors searched the databases of PubMed and Cochrane for studies that used a categorization of T2W ISI to predict the functional outcome after decompressive surgery for CSM. Selected studies were analyzed for the type of ISI classification used, patient selection, methodology and results. The level of evidence provided by each study was determined.

RESULTS

Twenty-two studies fulfilled our search criteria. There were 11 prospective studies and a total of 1,508 patients were studied. The majority of studies classified ISI based on either the longitudinal extent (12 studies) or the qualitative features of the ISI (10 studies). Three studies used both parameters to classify T2W ISI. Other classifications were based on the position of ISI (1 study), presence of snake-eye appearance on axial MR images (1 study) and signal intensity ratio (SIR) (1 study). Poorer functional outcomes correlated with sharp, intense ISI (6 studies) and multisegmental ISI (5 studies) (Class II evidence). Five of ten studies reported that the regression of ISI postoperatively was associated with better neurological outcomes (Class II evidence).

CONCLUSIONS

Methodological variations in previous studies made it difficult to compare studies and results. Both multisegmental T2W ISI and sharp, intense T2W ISI are associated with poorer surgical outcome (Class II evidence). The regression of T2W ISI postoperatively correlates with better functional outcomes (Class II). Future studies on the significance of ISI should ensure use of a uniform grading system, standardized outcome measures and multivariate analyses to control for other preoperative variables.

Clinical significance of MRI/(18)F-FDG PET fusion imaging of the spinal cord in patients with cervical compressive myelopathy

PURPOSE

(18)F-FDG PET is used to investigate the metabolic activity of neural tissue. MRI is used to visualize morphological changes, but the relationship between intramedullary signal changes and clinical outcome remains controversial. The present study was designed to evaluate the use of 3-D MRI/(18)F-FDG PET fusion imaging for defining intramedullary signal changes on MRI scans and local glucose metabolic rate measured on (18)F-FDG PET scans in relation to clinical outcome and prognosis.

METHODS

We studied 24 patients undergoing decompressive surgery for cervical compressive myelopathy. All patients underwent 3-D MRI and (18)F-FDG PET before surgery. Quantitative analysis of intramedullary signal changes on MRI scans included calculation of the signal intensity ratio (SIR) as the ratio between the increased lesional signal intensity and the signal intensity at the level of the C7/T1 disc. Using an Advantage workstation, the same slices of cervical 3-D MRI and (18)F-FDG PET images were fused. On the fused images, the maximal count of the lesion was adopted as the standardized uptake value (SUV(max)). In a similar manner to SIR, the SUV ratio (SUVR) was also calculated. Neurological assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy.

RESULTS

The SIR on T1-weighted (T1-W) images, but not SIR on T2-W images, was significantly correlated with preoperative JOA score and postoperative neurological improvement. Lesion SUV(max) was significantly correlated with SIR on T1-W images, but not with SIR on T2-W images, and also with postoperative neurological outcome. The SUVR correlated better than SIR on T1-W images and lesion SUV(max) with neurological improvement. Longer symptom duration was correlated negatively with SIR on T1-W images, positively with SIR on T2-W images, and negatively with SUV(max).

CONCLUSION

Our results suggest that low-intensity signal on T1-W images, but not on T2-W images, is correlated with a poor postoperative neurological outcome. SUV(max) of lesions showing increased signal intensity and SUVR measured on fusion MRI/PET scans are more sensitive parameters for predicting clinical outcome than signal intensity on the MRI scan.

Prospective cohort study of mild cervical spondylotic myelopathy without surgical treatment

OBJECT

Because the main pathology of cervical spondylotic myelopathy (CSM) is spinal cord damage due to compression, surgical treatment is usually recommended to improve patient symptoms and prevent exacerbation. However, lack of clarity of prognosis in cases that present with insignificant symptoms, particularly those of mild CSM, lead one to question the veracity of this course of action. The purpose of this study was to elucidate the prognosis of mild CSM without surgical intervention by evaluation of clinical symptoms and MR imaging findings.

METHODS

Sixty cases of mild CSM (42 males and 18 females, average age 57.2 years) presenting with scores of 13 or higher on the Japanese Orthopaedic Association (JOA) scale were treated initially by in-bed Good Samaritan cervical traction without surgery. These patients were enrolled between 1995 and 2003 and followed up periodically until the date of myelopathy deterioration or until the end of March 2009. The deterioration of myelopathy was defined as a decline in JOA score to less than 13 with a decrease of at least 2 points. As a prognostic factor, the authors used their classification of spinal cord shapes at their lateral sides on axial T1-weighted MR imaging. "Ovoid deformity" was classified as a situation in which both sides were round and convex, and "angular-edged deformity" where one or both sides exhibited an acute-angled lateral corner. The duration of follow-up was assessed as the tolerance rate of mild CSM using Kaplan-Meier survival analysis and compared between 2 groups classified by MR imaging findings. Furthermore, differences between groups were analyzed by various applications of the log-rank test.

RESULTS

Of the initial 60 cases, follow-up records existed for 55, giving a follow-up rate of 91.7% (38 males and 17 females, average age 56.1 years). The mean JOA score at end point was 14.1, which was not statistically different from the mean of 14.5 at the initial visit. Deterioration in myelopathy was observed in 14 (25.5%) of 55 cases, whereas 41 (74.5%) of 55 cases maintained mild extent myelopathy without deterioration through the follow-up period (mean 94.3 months). The total tolerance rate of mild CSM was 70%. However, there was a significant difference in the tolerance rate between the cases with angular-edged deformity (58%) and cases with ovoid deformity (95%; p = 0.049).

CONCLUSIONS

The tolerance rate of mild CSM was 70% in this study, which proved that the prognosis of mild CSM without surgical treatment was relatively good. However, the tolerance rate of the cases with angular-edged deformity was 58%. Therefore, surgical treatment should be considered when mild CSM cases show angular-edged deformity on axial MR imaging, even if patients lack significant symptoms.

Association of magnetic resonance imaging signal changes and outcome prediction after surgery for cervical spondylotic myelopathy

OBJECT

Few studies have evaluated the prognostic significance of different types of T2-weighted MR imaging changes in patients with cervical spondylotic myelopathy (CSM). The object of this study was to determine whether the type of increased signal intensity (ISI) was an independent predictor of outcome following central corpectomy in patients with CSM or ossification of the posterior longitudinal ligament (OPLL).

METHODS

Magnetic resonance images obtained in 197 patients who had undergone central corpectomy for CSM or OPLL were assessed for ISI within the cord on sagittal T2-weighted images and hypointensity on T1-weighted images. The T2-weighted changes were categorized as no change (Type 0), fuzzy (Type 1), or sharp (Type 2) based on the ISI characteristics. Outcomes were assessed as a change in Nurick grade of 1 grade or more from preoperatively to postoperatively, and cure as a follow-up Nurick grade of 0 or 1. Multilevel regression analysis was performed to identify predictors of change in Nurick grade ≥ 1 and cure.

RESULTS

There were 30 patients (15.2%) with Type 0, 104 patients (52.8%) with Type 1, and 63 patients (32%) with Type 2 ISI on MR images. Age, duration of symptoms, and preoperative Nurick grade were similar among the groups. A preoperative Nurick grade of 4 or 5 (OR 0.23, p < 0.001) and presence of Type 2 ISI on T2-weighted images (OR 0.48, p = 0.04) negatively influenced the probability of cure after surgery. Hypointensity on T1-weighted images was only seen in patients who had Type 2 ISI changes. Among the 63 patients with Type 2 ISI, the presence of T1-weighted hypointensity (16 patients) was found to negatively impact cure (OR 0.1, p = 0.04).

CONCLUSIONS

Increased signal intensity on preoperative T2-weighted MR images was seen in more than 80% of the cases. However, only Type 2 ISI on T2-weighted images had a prognostic significance of being associated with a decreased likelihood of cure in patients with CSM or OPLL. Hypointensity on T1-weighted images predicted a lower probability of cure among patients with Type 2 ISI on T2-weighted images.

Cervical spondylotic myelopathy: pathophysiology, clinical presentation, and treatment

Age-related changes in the spinal column result in a degenerative cascade known as spondylosis. Genetic, environmental, and occupational influences may play a role. These spondylotic changes may result in direct compressive and ischemic dysfunction of the spinal cord known as cervical spondylotic myelopathy (CSM). Both static and dynamic factors contribute to the pathogenesis. CSM may present as subclinical stenosis or may follow a more pernicious and progressive course. Most reports of the natural history of CSM involve periods of quiescent disease with intermittent episodes of neurologic decline. If conservative treatment is chosen for mild CSM, close clinical and radiographic follow-up should be undertaken in addition to precautions for trauma-related neurologic sequelae. Operative treatment remains the standard of care for moderate to severe CSM and is most effective in preventing the progression of disease. Anterior surgery is often beneficial in patients with stenotic disease limited to a few segments or in cases in which correction of a kyphotic deformity is desired. Posterior procedures allow decompression of multiple segments simultaneously provided that adequate posterior drift of the cord is attainable from areas of anterior compression. Distinct risks exist with both anterior and posterior surgery and should be considered in clinical decision-making.

Clinical significance of cerebrospinal fluid nitric oxide concentrations in degenerative cervical and lumbar diseases

In animal models of degenerative lumbar disease, inducible nitric oxide synthase (iNOS) is expressed in macrophages and Schwann cells following compression of the cauda equina. We previously reported that NO metabolites (nitrite plus nitrate: [NOx]) in the cerebrospinal fluid (CSF) correlate with postoperative pain relief in patients with degenerative lumbar disease and with neurologic recovery rate postoperatively or after conservative treatment in patients with spinal cord injury. The objective of the present study was to examine the relationship between [NOx] and neurologic severity, and recovery in degenerative cervical and lumbar diseases. Two hundred fifty-seven cases, including 85 patients with cervical compression myelopathy (CCM), 25 with cervical disc herniation (CDH), 70 with lumbar canal stenosis (LCS), and 77 with lumbar disc herniation (LDH), were examined. The CSF [NOx] was measured using the Griess method. Severity of neurologic impairment and clinical recovery was assessed using the Japanese Orthopedic Association score and Hirabayashi's method. [NOx] in CCM and LCS, but not CDH and LDH groups, was significantly higher than that in controls, and correlated with postoperative recovery rates, but not with preoperative neurologic severity. [NOx] significantly correlated with neurologic recovery following surgery for CCM and LCS.

Intramedullary high signal intensity and neurological status as prognostic factors in cervical spondylotic myelopathy

PURPOSE

The neurological outcome of cervical spondylotic myelopathy (CSM) may depend on multiple factors, including age, symptom duration, cord compression ratio, cervical curvature, canal stenosis, and factors related to magnetic resonance (MR) signal intensity (SI). Each factor may act independently or interactively with others. To clarify the factors in prognosis, we prospectively analyzed the outcomes of patients with myelopathy caused by soft disc herniation in correlation with magnetic resonance imaging (MRI) findings and other clinical parameters.

MATERIALS AND METHODS

From June 2006 to July 2009, we performed surgical operations in 137 patients with CSM. Of these patients, 70 (51.1%), including 45 men and 25 women with ventral cord compression at one or two levels, underwent anterior cervical discectomy and fusion. The mean duration of follow-up was 32.7 months. We surveyed the cervical curvature index (CCI), canal stenosis (Torg-Pavlov ratio), cord compression ratio, the length of SI change on T2WI, and clinical outcome using the Japanese Orthopedic Association (JOA) score for cervical myelopathy. The MRI SI was evaluated by grade: grade 0, no change in signal intensity; grade 1, light signal change; and grade 2, bright signal change on the T2WI. Multifactorial effects were identified by regression analysis.

RESULTS

The mean preoperative and postoperative JOA scores were 10.5 ± 2.9 and 14.9 ± 2.1, respectively (p < 0.05). The mean recovery rate based on the JOA score was 70.0 ± 20.1%. The respective preoperative JOA scores and recovery ratios(%) were 11.6 ± 2.3 and 81.5 ± 17.0% in 20 patients with SI grade 0; 10.8 ± 2.3 and 70.1 ± 17.3% in 25 patients with grade 1; and 9.2 ± 3.6 and 60.7 ± 20.9% in 25 patients with grade 2, respectively. Post-surgical neurological outcome showed no significant relationship to age, symptom duration, cervical alignment, stenosis, or cord compression.

CONCLUSIONS

Among the variables tested, preoperative neurological status and intramedullary signal intensity were significantly related to neurological outcome. The better the preoperative neurological status was, the better the post-operative neurological outcome. The SI grade on the preoperative T2WI was negatively related to neurological outcome. Hence, the severity of SI change and preoperative neurological status emerged as significant prognostic factors in post-operative CSM.

Comparison of prognostic value of different MRI classifications of signal intensity change in cervical spondylotic myelopathy

BACKGROUND CONTEXT

Signal intensity (SI) changes of the spinal cord on magnetic resonance imaging (MRI) in cervical spondylotic myelopathy (CSM) are thought to be a predictor of surgical outcome. However, the clinical significance of SI change remains controversial. Although several classifications exist for SI change, there are no previous studies comparing their prognostic significance.

PURPOSE

To determine the MRI classification of SI changes in patients with CSM that is useful for prognostication of surgical outcome.

STUDY DESIGN

Retrospective case study.

PATIENT SAMPLE

Patients who underwent cervical laminectomy for CSM between the time period of January 2000 and December 2005.

OUTCOME MEASURE

Clinical outcome was measured by the recovery rate (RR) and the postoperative Nurick grade.

METHODS

We retrospectively studied 35 of the 77 CSM patients (mean age, 57.8 years; range, 30-69; preoperative symptom duration, 9.3 months) who underwent cervical laminectomy and who met the inclusion criteria. Postoperative MRIs were performed at a mean of 51.3 months postsurgery to assess for resolution of preoperative signal changes. The pattern of spinal cord SI was classified in three different ways: based on high SI on T2-weighted images (T2WI) (Grade 0-absent, Grade 1-obscure, and Grade 2-intense); based on the extent of SI change on T2WI into focal (confined to one disc level) and multisegmental (more than one disc level); and based on T1-weighted image (T1WI) and T2WI changes into Group A (MRI normal/normal), no intramedullary SI abnormality on T1WI or T2WI; Group B (MRI normal/high SI), no intramedullary SI abnormality on T1WI and high intramedullary SI on T2WI; Group C (MRI low/high SI changes), low-intensity intramedullary signal abnormality on T1WI and high-intensity intramedullary signal abnormality on T2WI. Preoperative clinical findings and MRI abnormalities were correlated with outcomes (Nurick scores, RR) after surgical intervention.

RESULTS

Preoperative MRI studies demonstrated the following: Grade 0=1, Grade 1=13, Grade 2=13; focal=18, multisegmental=16; Group A=1; Group B=29; and Group C=5. Resolution of signal changes in T2WI was seen in most patients; however, four patients developed low SI in T1WI in the postoperative MRI. There was no significant difference in the RRs of patients with different grades in the T2WI or with focal or multisegmental SI changes (p=.47 and .28, respectively). In contrast, patients with low SI changes in T1WI were associated with a poor surgical outcome (p<.001). The linear regression model performed using low-intensity signal changes as a dependent variable and the RR as an independent variable confirmed the significance (p<.001) of low SI changes on T1WI as a predictor for surgical outcome.

CONCLUSIONS

A classification system of MRI signal changes that accommodates both T1WI and T2WI is more predictive of surgical outcome than those that include T2W SI changes alone. Postoperative MRI is useful to identify late onset of low T1W intensity changes in patients with poor neurological recovery.

Prognostic factors that affect the surgical outcome of the laminoplasty in cervical spondylotic myelopathy

Background

This study examined the prognostic factors that affect the surgical outcome of laminoplasty in cervical spondylotic myelopathy patients by comparative analysis.

Methods

Thirty nine patients, 26 males and 13 females, who were treated with laminoplasty for cervical myelopathy from September 2004 to March 2008 and followed up for 12 months or longer, were enrolled in this study. The mean age of the subjects was 62.4 years (range, 37 to 77 years). The patients' age, number of surgical segments, spinal cord compression ratio, segment number, level, localized marginal pattern of high signal intensity within the spinal cord in the T2 image, preoperative Japanese Orthopaedic Association Scoring System (JOA) score with the recovery ratio were compared respectively. The JOA score was used for an objective assessment of the patients' preoperative and postoperative clinical status. The recovery ratios of surgery were graded using the Hirabayashi equation. Statistical analysis was carried out using Pearson correlation analysis.

Results

The patients' JOA score increased from a preoperative score of 11.1 (range, 5 to 16) to a postoperative score of 14.9 (range, 7 to 17). The average recovery ratio was 65.8% (range, 0 to 100%). The number of segments with high signal changes in the T2 image, a localized marginal pattern with high signal change, signal intensity changes in the upper cervical spinal cord were inversely associated with the recovery ratio, whereas the spinal cord compression ratio showed a significant positive correlation. However, the currently known prognostic factors, such as number of surgical segment, age, and preoperative JOA score, showed no statistically significant correlation.

Conclusions

The number of segments, localized marginal pattern, rostral location of signal intensity changes with a high signal change in the T2 image and a low spinal cord compression ratio in cervical spondylotic myelopathy patients treated by laminoplasty can indicate a poor prognosis.

Preoperative patient selection with magnetic resonance imaging, computed tomography, and electroencephalography: does the test predict outcome after cervical surgery?

OBJECT

The objective of this systematic review was to use evidence-based medicine to assess whether preoperative imaging or electromyography (EMG) predicts surgical outcomes in patients undergoing cervical surgery.

METHODS

The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to the preoperative imaging and EMG. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

RESULTS

Preoperative MR imaging and CT myelography are successful in confirming clinical radiculopathy (Class II). Multilevel T2 hyperintensity, T1 focal hypointensity combined with T2 focal hyperintensity, and spinal cord atrophy each convey a poor prognosis (Class III). There is conflicting data concerning whether focal T2 hyperintensity or cervical stenosis are associated with a worse outcome. Electromyography has mixed utility in predicting outcome (Class III).

CONCLUSIONS

Magnetic resonance imaging or CT myelography are important for preoperative assessment. Magnetic resonance imaging may be helpful in assessing prognosis, whereas EMG has mixed utility in assessing outcome.

High-resolution magnetic resonance imaging and 18FDG-PET findings of the cervical spinal cord before and after decompressive surgery in patients with compressive myelopathy

STUDY DESIGN

Evaluation of cervical spinal cord (CSC) of patients with compressive myelopathy by magnetic resonance imaging (MRI) and high-resolution (18F)fluoro-deoxyglucose (18FDG) positron emission tomography (PET).

OBJECTIVE

To determine changes in morphology, intramedullary signal intensity, and glucose metabolic rate in CSC after decompression, and to assess the utility of 18FDG-PET in evaluation of patients with cervical myelopathy.

SUMMARY OF BACKGROUND DATA

The significance of CSC enlargement after decompression and signal intensity changes within the cord remain elusive. No data are available on metabolic activity of the compressed CSC. Only a few studies have examined correlation between high-resolution MRI and 18FDG-PET neuroimaging in cervical myelopathy.

METHODS

We studied 24 patients who underwent cervical decompressive surgery in terms of postoperative neurologic improvement and changes in MRI and 18FDG-PET. Neurologic status was assessed by the Japanese Orthopedic Association scoring system (17-point scale). Signal intensity change in the cord was qualitatively assessed on both T1- and T2-weighted images. The transverse area of the CSC on MRIs and glucose metabolic rate (standardized uptake value [SUV]) from 18FDG-PET were measured digitally.

RESULTS

Neurologic improvement correlated with preoperative CSC transverse area at maximal compression (P < 0.01) and at follow-up (P < 0.001) and with mean SUV before surgery (P < 0.01) and at follow-up (P < 0.05). Preoperative signal intensity change on MRIs (low intramedullary signal intensity abnormality on T1-weighted image and high intramedullary on T2-weighted image) correlated negatively with neurologic improvement rate (P < 0.05). The transverse area of the CSC was significantly smaller after surgery in patients with preoperative MRI signal intensity changes (P < 0.05). The SUV at follow-up tended to normalize in association with neurologic improvement.

CONCLUSION

Our results showed that postoperative neurologic improvement in patients with cervical compressive myelopathy correlated with increased transverse area of the spinal cord, signal intensity change on both T1- and T2-weighted image, and the mean SUV.

A review of prognostic factors for surgical outcome of ossification of the posterior longitudinal ligament of cervical spine

For patients with ossification of the posterior longitudinal ligament (OPLL) who have neurological-symptoms, surgery is necessary but not always effective. Various clinical factors influence the surgical outcome. The studies identifying these factors have been inconclusive and conflicting. It is essential for surgeons to understand the significance of the factors and choose the optimal therapeutic strategy for OPLL. The objective of this review is to determine the clinical factors predictive of the surgical outcome of cervical OPLL. The authors conducted a review of literature published in the English language. They examined studies in which the correlation between clinical factors and outcome were statistically evaluated. The results showed that the traverse area of the spinal cord, the spinal cord-evoked potentials (SCEPs), the increase of the range of motion in the cervical spine (ROM), diabetes, history of trauma, the onset of ossification of the ligament flavum (OLF) in the thoracic spine, snake-eye appearance (SEA) and incomplete decompression may be predictive factors. Age at surgery seems to be closely related to the outcome of posterior surgical procedure. Whether the neurological score, OPLL type, pre-operative duration of symptoms, focal intra-medullar high signal intensity in T2-weighted (IMHSI) and progression of OPLL or kyphosis and expansion of the spinal canal predict the surgical outcome remains unclear. The use of uniform neurological score and proper statistic analysis should facilitate comparison of data from different studies. It is important to analyze the effect of each factor on groups with different surgical procedures as well as patients with different compressive pathology. Research on the etiology and pathology of cervical myelopathy due to OPLL should be helpful in precisely understanding these clinical factors and predicting surgical outcome.

Prognostic relevance of the postoperative evolution of intramedullary spinal cord changes in signal intensity on magnetic resonance imaging after anterior decompression for cervical spondylotic myelopathy

Object

Areas of intramedullary signal intensity changes (hypointensity on T1-weighted magnetic resonance [MR] images and hyperintensity on T2-weighted MR images) in patients with cervical spondylotic myelopathy (CSM) have been described by several investigators. The role of postoperative evolution of these alterations is still not well known.

Methods

A total of 47 patients underwent MR imaging before and at the end of the surgical procedure (intraoperative MR imaging [iMRI]) for cervical spine decompression and fusion using an anterior approach. Imaging was performed with a 1.5-tesla scanner integrated with the operative room (BrainSuite). Patients were followed clinically and evaluated using the Japanese Orthopaedic Association (JOA) and Nurick scales and also underwent MR imaging 3 and 6 months after surgery.

Results

Preoperative MR imaging showed an alteration (from the normal) of the intramedullary signal in 37 (78.7%) of 47 cases. In 23 cases, signal changes were altered on both T1- and T2-weighted images, and in 14 cases only on T2-weighted images. In 12 (52.2%) of the 23 cases, regression of hyperintensity on T2-weighted imaging was observed postoperatively. In 4 (17.4%) of these 23 cases, regression of hyperintensity was observed during the iMRI at the end of surgery. Residual compression on postoperative iMRI was not detected in any patients.

A nonsignificant correlation was observed between postoperative expansion of the transverse diameter of the spinal cord at the level of maximal compression and the postoperative JOA score and Nurick grade. A statistically significant correlation was observed between the surgical result and the length of a patient's clinical history. A significant correlation was also observed according to the preoperative presence of intramedullary signal alteration. The best results were found in patients without spinal cord changes of signal, acceptable results were observed in the presence of changes on T2-weighted imaging only, and the worst results were observed in patients with spinal cord signal changes on both T1- and T2-weighted imaging. Finally, a statistically significant correlation was observed between patients with postoperative spinal cord signal change regression and better outcomes.

Conclusions

Intramedullary spinal cord changes in signal intensity in patients with CSM can be reversible (hyperintensity on T2-weighted imaging) or nonreversible (hypointensity on T1-weighted imaging). The regression of areas of hyperintensity on T2-weighted imaging is associated with a better prognosis, whereas the T1-weighted hypointensity is an expression of irreversible damage and, therefore, the worst prognosis. The preliminary experience with this patient series appears to exclude a relationship between the time of signal intensity recovery and outcome of CSM.

Cross-sectional transverse area and hyperintensities on magnetic resonance imaging in relation to the clinical picture in cervical spondylotic myelopathy

STUDY DESIGN

Prospective observational cohort study.

OBJECTIVE

To ascertain the threshold of critical spondylotic cervical cord compression and its relation to MRI-increased signal intensities.

SUMMARY OF BACKGROUND DATA

The critical degree of spinal cord compression required to induce significant clinical signs remains unknown.

METHODS

The study group consisted of 243 patients (mean age, 53.9 +/- 9.8 years), with spondylotic cervical spine compression. The transverse cross-sectional area of the spinal cord at the level of maximum compression was measured, while MRI hyperintensities were recorded and related to clinical status and quantified by modified JOA score (mJOA).

RESULTS

A statistically significant difference in mJOA was shown between patients with a spinal cord sectional area of under 50 mm2 and a group of patients with a spinal cord sectional area of over 60 mm2. This difference was highly significant (P = 0.001) in a subgroup with MRI hyperintensities (187 patients, P = 0.001), whereas within the group of patients without hyperintensities this difference was not observed (P = 0.63).

CONCLUSION

The critical degree of spinal cord compression needed to induce clinically significant signs was found between 50 and 60 mm2 of cross-sectional transverse area at the level of maximal compression in association with MRI hyperintensities.

Prognostic factors for deterioration of patients with cervical spondylotic myelopathy after nonsurgical treatment

STUDY DESIGN

A prospective study involving 56 patients with cervical spondylotic myelopathy (CSM) was conducted.

OBJECTIVE

To investigate the outcomes and prognostic factors for CSM after nonsurgical treatment.

SUMMARY OF BACKGROUND DATA

The superiority of surgical treatment over nonsurgical treatment has not been confirmed in mild forms of CSM. Outcomes and prognostic factors for nonsurgical treatment of mild forms of CSM are not well understood.

METHODS

Clinical signs and symptoms of CSM were assessed by Japanese Orthopedic Association (JOA) scores. Nonsurgical treatment was selected for patients with mild forms of CSM (JOA >or=13 patients). Seventy patients with mild forms of CSM were enrolled in the study between 1995 and 2003. The follow-up rate was 80.0%. Prognostic factors that exacerbate clinical symptoms of CSM were examined, such as age, gender, follow-up period, developmental or dynamic factors on plain lateral radiograph, high signal intensity area on T2-weighted sagittal MRI, and the extent of maximum cord compression; partial or circumferential spinal cord compression, on axial MRI. Univariate and multivariate logistic regression analysis were carried out to test for significant prognostic factors.

RESULTS

There was, on average, no statistically significant deterioration in JOA scores after nonsurgical treatment. However, 11 of 56 patients deteriorated after nonsurgical treatment. The only factor that significantly exacerbated clinical symptoms of CSM was circumferential spinal cord compression in the maximum compression segment on axial MRI. Indeed, 10 of 33 CSM patients with circumferential spinal cord compression on axial MRI deteriorated after nonsurgical treatment.

CONCLUSION

Outcomes of mild forms of CSM during nonsurgical treatment were generally good as shown by average JOA scores. The only prognostic factor for mild forms of CSM was circumferential spinal cord compression in the maximum compression segment on axial MRI. Surgical treatment can be considered for patients with this prognostic factor.

Cervical compression myelopathy: is fusion the main prognostic indicator?

Object

A variety of factors may affect the neurological improvement in patients with cervical compression myelopathy (CCM) after surgery. The aim of this study was to report and discuss the prognostic factors in a group of patients with insufficient decompression of the spinal canal.

Methods

A prospective follow up and analysis of 20 consecutive patients with CCM treated between 2000 and 2002 was performed. All patients were surgically treated via an anterior approach, either by anterior cervical discectomy and fusion with instrumentation or by cervical corpectomy and fusion with instrumentation. The surgical results were examined using the modified Japanese Orthopaedic Asssociation disability scale, with reference to the findings of magnetic resonance imaging, computed tomography, and radiography. Seventeen patients (85%) experienced a 50% or more recovery rate as calculated using the Hirabayashi formula during the follow-up period (mean 32.5 months), despite a persistently narrow spinal canal and permanent or increased intramedullary high-intensity signal after surgery.

Conclusions

Results of the study showed that patients with CCM benefited from anterior cervical discectomy and fusion with instrumentation or cervical corpectomy and fusion with instrumentation procedures despite insufficient decompression of the spinal canal. Fusion of the affected level(s) might be the reason for the acquired high recovery rates. The authors also conclude that the neurological improvement is not correlated with the reversal of or decrease in the intramedullary high-intensity signal change after surgery.

DORSAL SURGERY FOR MYELOPATHY AND MYELORADICULOPATHY

OBJECTIVE

To review the dorsal approaches to the cervical spine for myelopathy and myeloradiculopathy.

METHODS

The literature was reviewed in reference to dorsal approaches for cervical myelopathy and myeloradiculopathy.

RESULTS

There are a variety of surgical approaches in the management of cervical myelopathy and myeloradiculopathy. Deciding which is the best method for any individual requires the surgeon to be aware of the advantages of each technique, as well as the complications and limitations of each approach.

CONCLUSION

Laminectomy is the traditional technique used for multilevel cervical stenosis. The complications related to laminectomy, such as late neurological decline, kyphosis, instability, and postoperative radiculopathy, led to laminectomy with fusion. In Japan, dissatisfaction with both laminectomy and laminectomy with fusion led to the development of laminoplasty for dorsal treatment of multilevel cervical stenosis. This article highlights the salient features of preoperative evaluation in this patient population as it pertains to dorsal surgical approaches. Additionally, the techniques of laminectomy, laminectomy with fusion, and laminoplasty are compared, and the results are reviewed.

Laminoplasty: a review of its role in compressive cervical myelopathy

BACKGROUND CONTEXT

The currently accepted surgical treatments for compressive cervical myelopathy include both anterior and posterior decompression. Anterior approaches including multilevel discectomy with fusion or vertebral corpectomy with strut grafting, both with and without instrumentation, have enjoyed successful outcomes, but have been associated with select postoperative complications. Laminoplasty has been developed to decompress the spine posteriorly while avoiding the spinal destabilization seen after laminectomy.

PURPOSE

The purpose of this article is to provide a review of the various techniques, biomechanical basis, predictive value of imaging modalities, clinical outcomes, and postoperative complications associated with cervical laminoplasty.

STUDY DESIGN

A review of the literature.

METHODS

A comprehensive literature review using Medline was performed identifying relevant articles that addressed the techniques, clinical outcomes, and complications after cervical laminoplasty, as well as preoperative radiographic predictors of outcome.

RESULTS

The various modifications of cervical laminoplasty have generally been associated with excellent clinical outcomes when used for myelopathy secondary to cervical spondylosis or ossification of the posterior longitudinal ligament (OPLL). Recent long-term studies have identified issues with this technique including axial neck pain, canal restenosis, nerve root palsy, diminished cervical motion, and loss of cervical lordotic alignment.

CONCLUSIONS

Cervical laminoplasty remains a reliable procedure for posterior decompression of the spine, but the optimal approach to cervical myelopathy must take into account both patient and disease characteristics, as well as the capabilities and experience of the surgeon.

Predictors of Outcome of Surgery for Cervical Compressive Myelopathy: Retrospective Analysis and Prospective Study

The outcomes of surgical treatment in 80 patients with cervical compressive myelopathy were retrospectively reviewed to examined the correlations between surgical outcomes and the following seven predictive factors: age at surgery, duration of symptoms, severity of myelopathy, number of compressed segments, intramedullary high intensity segments on T(2)-weighted magnetic resonance (MR) imaging, surgical method, and the type of disease. The recovery rates were evaluated at 3 months after the surgery. Significant correlations were observed between recovery rate and duration of symptoms, severity of myelopathy, and high intensity segments on T(2)-weighted MR imaging. No statistical correlation was observed with the other factors. Multivariate analysis revealed significant correlations between recovery rate and duration of symptoms and number of high intensity segments on T(2)-weighted MR imaging. The multiple regression equation was expressed as follows: recovery rate = 82.981 + 0.101 x (age) - 0.675 x (duration) - 1.452 x (number of compressed segments) - 1.451 x (preoperative Neurosurgical Cervical Spine Scale) - 13.826 x (number of high intensity segments). Based on this predicted formula, we compared the predicted and actual recovery rates for 17 patients treated recently. The two values were similar except in two patients with long duration of symptoms. We conclude that the surgical outcome can be predicted to a certain extent and this information could be provided to patients considering surgery for cervical compressive myelopathy.

Presymptomatic spondylotic cervical cord compression

STUDY DESIGN

We conducted a cohort study of clinically asymptomatic spondylotic cervical cord compression cases with the primary end point of the development of clinical signs of cervical myelopathy.

OBJECTIVES

To investigate whether various demographic, clinical, radiologic, and electrophysiological parameters could predict progression from clinically asymptomatic (preclinical) spondylotic cervical cord compression to symptomatic myelopathy.

SUMMARY OF BACKGROUND DATA

The data available on the prediction of the outcome in surgical and conservative treatment of spondylotic cervical myelopathy are controversial. Little is known about the clinical natural history of asymptomatic magnetic resonance image-detected spondylotic cervical cord compression and/or changes of signal intensity.

METHODS

A group of 66 patients (32 women, 34 men, median age 50 years) with magnetic resonance signs of spondylotic cervical cord compression but without clear clinical signs of myelopathy was followed prospectively for at least 2 years (range, 2-8 years; median, 4 years). Various demographic, clinical, imaging, and electrophysiological parameters were correlated with clinical outcome.

RESULTS

Clinical signs of myelopathy during the follow-up period were detected in 13 patients (19.7%). The only variables significantly associated with the development of clinically symptomatic spondylotic cervical myelopathy (SCM) were the presence of symptomatic cervical radiculopathy, electromyographic signs of anterior horn lesion, and abnormal somatosensory-evoked potentials. A multivariate logistic regression model based on these variables correctly classified 90% of cases into 2 subgroups: a group with development of symptomatic SCM and that without clinical manifestation of subclinical cervical cord compression.

CONCLUSIONS

Electrophysiological abnormalities together with clinical signs of cervical radiculopathy could predict clinical manifestation of preclinical spondylotic cervical cord compression.

Predictive factors for mild forms of spondylotic cervical myelopathy treated conservatively or surgically

A prospective 3-year randomized study comparing conservative and surgical treatment of spondylotic cervical myelopathy to establish predictive factors for outcome after conservative treatment and surgery. The clinical, electrophysiological and imaging parameters were examined to reveal how they characterized the clinical outcome. Statistically, pair-wise and multiple comparisons of different were used with the independent t-test and on one-way anova models followed by Tukey multiple-range tests. The patients with a good outcome in the conservatively treated group were of older age before treatment, had normal central motor conduction time (CMCT), and possessed a larger transverse area of the spinal cord. The patients with a good outcome in the surgically treated group had a more serious clinical picture (expressed in mJOA score and slower walk). Patients should rather be treated conservatively if they a spinal transverse area larger than 70 mm2, are of older age, and have normal CMCT. Surgery is more suitable for patients with clinically worse status and a lesser transverse area of spinal cord.

Predictive factors for spondylotic cervical myelopathy treated conservatively or surgically

A prospective 3-year randomized study comparing conservative and surgical treatment of spondylotic cervical myelopathy to establish predictive factors for outcome after conservative treatment and surgery. The clinical, electrophysiological and imaging parameters were examined to reveal how they characterized the clinical outcome. The patients with a good outcome in the conservatively treated group were of older age before treatment, had normal central motor conduction time (CMCT), and possessed a larger transverse area of the spinal cord. The patients with a good outcome in the surgically treated group had a more serious clinical picture (expressed in mJOA score and slower walk). Patients should rather be treated conservatively if they have a spinal transverse area larger than 70 mm2, are of older age and have normal CMCT. Surgery is more suitable for patients with clinically worse status and a lesser transverse area of spinal cord.

Presymptomatic spondylotic cervical cord compression

STUDY DESIGN

We conducted a cohort study of clinically asymptomatic spondylotic cervical cord compression cases with the primary end point of the development of clinical signs of cervical myelopathy.

OBJECTIVES

To investigate whether various demographic, clinical, radiologic, and electrophysiological parameters could predict progression from clinically asymptomatic (preclinical) spondylotic cervical cord compression to symptomatic myelopathy.

SUMMARY OF BACKGROUND DATA

The data available on the prediction of the outcome in surgical and conservative treatment of spondylotic cervical myelopathy are controversial. Little is known about the clinical natural history of asymptomatic magnetic resonance image-detected spondylotic cervical cord compression and/or changes of signal intensity.

METHODS

A group of 66 patients (32 women, 34 men, median age 50 years) with magnetic resonance signs of spondylotic cervical cord compression but without clear clinical signs of myelopathy was followed prospectively for at least 2 years (range, 2-8 years; median, 4 years). Various demographic, clinical, imaging, and electrophysiological parameters were correlated with clinical outcome.

RESULTS

Clinical signs of myelopathy during the follow-up period were detected in 13 patients (19.7%). The only variables significantly associated with the development of clinically symptomatic spondylotic cervical myelopathy (SCM) were the presence of symptomatic cervical radiculopathy, electromyographic signs of anterior horn lesion, and abnormal somatosensory-evoked potentials. A multivariate logistic regression model based on these variables correctly classified 90% of cases into 2 subgroups: a group with development of symptomatic SCM and that without clinical manifestation of subclinical cervical cord compression.

CONCLUSIONS

Electrophysiological abnormalities together with clinical signs of cervical radiculopathy could predict clinical manifestation of preclinical spondylotic cervical cord compression.

Cervical Myelopathy Due to OPLL

BACKGROUND

Concerning the relationship between morphology and clinical outcome, there have been many reports using computed tomography/myelography but not so many using axial magnetic resonance imaging (MRI) of the spinal cord. This is the first report to correlate axial cord image, intensity changes in MRI, and cord expansion pattern using intraoperative ultrasonography.

OBJECTIVE

The objectives were to correlate MRI studies, axial cord images/expansion, and changes in MRI intensity to see if there is a direct prognostic significance to these changes and to determine whether preoperative axial MRI images of the spinal cord predict recovery from compressive myelopathy.

METHODS

Posterior cervical decompressions with laminoplasty were performed in 44 patients with cervical myelopathy due to ossification of the posterior longitudinal ligament. On T2-weighted MR images, the cross-sectional shape of the cord at the level of maximal compression was categorized as boomerang, teardrop, or triangle. Additionally, with use of intraoperative ultrasonography, the expansion pattern of the cord that occurred intraoperatively was contrasted with that seen on postoperative MR images.

RESULTS

Clinical recovery rates were the worst for those with triangular, intermediate for those with boomerang, and the best for those with teardrop shape. Preoperative low T1 and high T2 signals were found in most cases with triangular cord configurations. Triangular cord configurations showed the least expansion among the three categorized spinal cords.

CONCLUSION

Patients with triangular deformity of the cord have atrophy as confirmed on MR studies where there is a low T1 and high T2 signal in the cord. Poor postoperative clinical recovery correlates with the lack of postoperative cord expansion on either MR or ultrasound evaluations. Those with either teardrop or boomerang deformities demonstrate a relatively good recovery rate.

Clinical and radiographic results of expansive lumbar laminoplasty in patients with spinal stenosis

BACKGROUND

In 1981, we developed a technique of expansive lumbar laminoplasty to alleviate the problems of conventional laminectomy in the treatment of spinal stenosis. The purposes of this study were to assess the long-term outcome following expansive lumbar laminoplasty and to investigate the postoperative problems.

METHODS

Fifty-four patients underwent expansive lumbar laminoplasty for the treatment of spinal stenosis. There were forty-three men and eleven women with a mean age of 52.6 years. The average length of follow-up was 5.5 years. Preoperatively, twenty-five patients had degenerative stenosis; thirteen, stenosis due to spondylolisthesis; twelve, combined stenosis (disc herniation and stenosis); and six, hyperostotic stenosis. (Two patients with hyperostotic stenosis and spondylolisthesis were included in both groups.) The clinical results were assessed with use of the Japanese Orthopaedic Association score, and the rate of recovery was calculated. Radiographic findings were analyzed on the basis of the cross-sectional area of the spinal canal, kyphosis, range of motion of the lumbar spine, and the rate of interlaminar fusion.

RESULTS

The average recovery rate at the time of the last follow-up was 69.2% for patients with degenerative stenosis, 66.5% for patients with combined stenosis, 65.2% for those with hyperostotic stenosis, and 54.7% for those with spondylolisthesis. The factors resulting in a poor recovery were an older age and insufficient decompression of the lateral stenosis. During the follow-up period, the Japanese Orthopaedic Association score became worse for seven patients, six patients had lesions develop at the level adjacent to the laminoplasty, and five patients had spondylolisthesis develop. Interlaminar fusion was observed in twenty-two patients (41%).

CONCLUSIONS

The satisfactory results of expansive lumbar laminoplasty were maintained at an average of 5.5 years after surgery. The best indications for the lumbar laminoplasty procedure were young and active patients with central spinal stenosis.

Square cervical laminoplasty incorporating spinous process: surgical technique

BACKGROUND

We have used a laminoplasty technique in multilevel cervical canal stenosis that incorporates spinous process in the neural arch and does not require free graft or foreign material.

METHODS

In this technique, laminae and spinous processes were used to enlarge stenotic cervical spinal canal. Three patients (mean age 34.6 years) formed the study group with a mean follow-up period of 24.6 months. Postoperative computed tomography (CT) and lateral radiographs were used to assess results in terms of bony union, canal diameter, and alignment of cervical spine.

RESULTS

All patients noted some improvement in both sensory and motor functions. The average increase in sagittal diameter of cervical spinal canal was 4.2 mm, and decrease in range of motion (ROM) was 13.2 degrees. Bony fusions at the gutters were seen after 6 months.

CONCLUSION

This new technique of cervical laminoplasty is safe, effective, relatively easy, and avoids complications related to free grafts or metallic or nonmetallic foreign materials used in other techniques

Minimum 10-year followup after en bloc cervical laminoplasty

The long-term outcome (> 10 years) after cervical laminoplasty was assessed and the postoperative problems were clarified. One hundred thirty-three patients had laminoplasty between 1981 and 1989 for treatment of cervical myelopathy and 126 patients were available for the current study. The clinical results were evaluated using the Japanese Orthopaedic Association score. The radiologic findings were analyzed by postural anomalies and range of motion. The average preoperative score was 9.1 points, and the postoperative score improved to 13.7 points within a year. The Japanese Orthopaedic Association score and recovery rate were maintained at 13.4 points and 55.1% at the last followup. In 20 patients, the Japanese Orthopaedic Association score worsened during the followup. The causes of deterioration were axial spread of ossification of the posterior longitudinal ligament, other spinal lesions, cerebral infarction, and peripheral neuropathy. Postoperative cervical radiculopathy occurred in nine patients. Postoperative radiculopathy resolved in five patients, but remained in four patients. Kyphotic changes were observed in eight patients. The recovery rate in patients with kyphosis was poor. The postoperative range of motion decreased to 25.1% of preoperative range of motion. Sixty one percent of patients had a reduction of range of motion. Satisfactory results of cervical laminoplasty were maintained for more than 10 years after surgery; however, there were several postoperative problems, such as neurologic deterioration, postoperative radiculopathy, progression of kyphosis, and range of motion limitation.

Laminectomy and Posterior Cervical Plating for Multilevel Cervical Spondylotic Myelopathy and Ossification of the Posterior Longitudinal Ligament: Effects on Cervical Alignment, Spinal Cord Compression, and Neurological Outcome

OBJECTIVE

Multilevel anterior decompressive procedures for cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament may be associated with a high incidence of neurological morbidity, construct failure, and pseudoarthrosis. We theorized that laminectomy and stabilization of the cervical spine with lateral mass plates would obviate the disadvantages of anterior decompression, prevent the development of kyphotic deformity frequently seen after uninstrumented laminectomy, decompress the spinal cord, and produce neurological results equal or superior to those achieved by multilevel anterior procedures.

METHODS

We retrospectively reviewed the records of 38 patients who underwent laminectomy and lateral mass plating for cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament between January 1994 and November 2001. Seventy-six percent of patients had spondylosis, 18% had ossification of the posterior longitudinal ligament, and 5% had both. Clinical presentation included upper extremity sensory complaints (89%), gait difficulty (70%), and hand use deterioration (67%). Spasticity was present in 83%, and weakness of one or more muscle groups was seen in 79%. Spinal cord signal abnormality on sagittal T2-weighted magnetic resonance imaging (MRI) was seen in 68%. Neurological evaluation was performed using a modification of the Japanese Orthopedic Association Scale for functional assessment of myelopathy, the Cooper Scale for separate evaluation of upper and lower extremity motor function, and a five-point scale for evaluation of strength in individual muscle groups. Lateral cervical spine x-rays were analyzed using a curvature index to determine maintenance of alignment. Each surgically decompressed level was graded on a four-point scale using axial MRI to assess the adequacy of decompression. Late follow-up was conducted by telephone interview.

RESULTS

Laminectomy was performed at a mean 4.6 levels. Follow-up was obtained at a mean of 30.2 months after the procedure. The score on the modified Japanese Orthopedic Association scale improved in 97% of patients from a mean of 12.9 preoperatively to 15.58 postoperatively (P&lt; 0.0001). In the upper extremities, function measured by the Cooper Scale improved from 1.8 to 0.7 (P&lt; 0.0001), and in the lower extremities, function improved from 1.0 to 0.4 (P&lt; 0.0002). There was a statistically significant improvement in strength in the triceps (P&lt; 0.0001), iliopsoas (P&lt; 0.0002), and hand intrinsic muscles (P&lt; 0.0001). X-rays obtained at a mean of 5.9 months after surgery revealed no change in spinal alignment as measured by the curvature index. There was a decrease in the mean preoperative compression grade from 2.46 preoperatively to 0.16 postoperatively (P&lt; 0.0001). There was no correlation between neurological outcome and the presence of spinal cord signal change on T2-weighted MRI scans, patient age, duration of symptoms, or preoperative medical comorbidity.

CONCLUSION

Multilevel laminectomy and instrumentation with lateral mass plates is associated with minimal morbidity, provides excellent decompression of the spinal cord (as visualized on MRI), produces immediate stability of the cervical spine, prevents kyphotic deformity, and precludes further development of spondylosis at fused levels. Neurological outcome is equal or superior to multilevel anterior procedures and prevents spinal deformity associated with laminoplasty or noninstrumented laminectomy.