Fall-related Deterioration of Subjective Symptoms in Patients with Cervical Myelopathy

Clinical outcome of surgical management of mild cervical compressive myelopathy based on minimum clinically important difference

BACKGROUND CONTEXT

Cervical compressive myelopathy (CCM), caused by cervical spondylosis (cervical spondylotic myelopathy [CSM]) or ossification of the posterior longitudinal ligament (OPLL), is a common neurological disorder in the elderly. For moderate/severe CCM, surgical management has been the first-line therapeutic option. Recently, surgical management is also recommended for mild CCM, and a few studies have reported the surgical outcome for this clinical population. Nonetheless, the present knowledge is insufficient to determine the specific surgical outcome of mild CCM.

PURPOSE

To examine the surgical outcomes of mild CCM while considering the minimum clinically important difference (MCID).

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Patients who underwent subaxial cervical surgery for CCM caused by CSM and OPLL between 2013 and 2022 were enrolled.

OUTCOME MEASURES

The Japanese Orthopedic Association score (JOA score) was employed as the clinical outcomes. Based on previous reports, the JOA score threshold to determine mild myelopathic symptoms was set at ≥14.5 points, and the MCID of the JOA score for mild CCM was set at 1 point.

METHODS

The patients with a JOA score of ≥14.5 points at baseline were stratified into the mild CCM and were examined while considering the MCID. The mild CCM cohort was dichotomized into the improvement group, including the patients with an achieved MCID (JOA score ≥1 point) or with a JOA score of 17 points (full mark) at 1 year postoperatively, and the nonimprovement group, including the others. Demographics, symptomatology, radiographic findings, and surgical procedure were compared between the two groups and studied using the receiver operating characteristic (ROC) curve.

RESULTS

Of 335 patients with CCM, 43 were stratified into the mild CCM cohort (mean age, 58.5 years; 62.8% male). Among them, 25 (58.1 %) patients were assigned to the improvement group and 18 (41.9 %) were assigned to the nonimprovement group. The improvement group was significantly younger than the nonimprovement group; however, other variables did not significantly differ. ROC curve analysis showed that the optimal cutoff point of the patient's age to discriminate between the improvement and nonimprovement groups was 58 years with an area under the curve of 0.702 (p=.015).

CONCLUSIONS

In the present study, the majority of patients with mild CCM experienced improvement reaching the MCID of JOA score at 1 year postoperatively. The present study suggests that for younger patients with mild CCM, especially those aged below 58 years, subjective neurological recovery is more likely to be obtained. Meanwhile, the surgery takes on a more prophylactic significance to halt disease progression for older patients. The results of this study can help in the decision-making process for this clinical population.

Management of Cervical Spinal Cord Injury without Major Bone Injury in Adults

The incidence of cervical spinal cord injury (CSCI) without major bone injury is increasing, possibly because older people typically have pre-existing cervical spinal canal stenosis. The demographics, neurological injury, treatment, and prognosis of this type of CSCI differ from those of CSCI with bone or central cord injury. Spine surgeons worldwide are debating on the optimal management of CSCI without major bone injury. Therefore, this narrative review aimed to address unresolved clinical questions related to CSCI without major bone injury and discuss treatment strategies based on current findings. The greatest divide among spine surgeons worldwide hinges on whether surgery is necessary for patients with CSCI without major bone injury. Certain studies have recommended early surgery within 24 h after injury; however, evidence regarding its superiority over conservative treatment remains limited. Delayed MRI may be beneficial; nevertheless, reliable factors and imaging findings that predict functional prognosis during the acute phase and ascertain the necessity of surgery should be identified to determine whether surgery/early surgery is better than conservative therapy/delayed surgery. Quality-of-life assessments, including neuropathic pain, spasticity, manual dexterity, and motor function, should be performed to examine the superiority of surgery/early surgery to conservative therapy/delayed surgery.

A screening method for cervical myelopathy using machine learning to analyze a drawing behavior

Early detection of cervical myelopathy (CM) is important for a favorable outcome, as its prognosis is poor when left untreated. We developed a screening method for CM using machine learning-based analysis of the drawing behavior of 38 patients with CM and 66 healthy volunteers. Using a stylus pen, the participants traced three different shapes displayed on a tablet device. During the tasks, writing behaviors, such as the coordinates, velocity, and pressure of the stylus tip, along with the drawing time, were recorded. From these data, features related to the drawing pressure, and time to trace each shape and combination of shapes were used as training data for the support vector machine, a machine learning algorithm. To evaluate the accuracy, a receiver operating characteristic curve was generated, and the area under the curve (AUC) was calculated. Models with triangular waveforms tended to be the most accurate. The best triangular wave model identified patients with and without CM with 76% sensitivity and 76% specificity, yielding an AUC of 0.80. Our model was able to classify CM with high accuracy and could be applied to the development of disease screening systems useful outside the hospital setting.

Comparative Study of Anticipatory Postural Adjustments between Normal and Cervical Myelopathy Patients

Patients with cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament have been considered to be prone to falls due to lower extremity dysfunction and gait instability. Anticipatory postural adjustments (APAs) are unconscious muscular activities to counterbalance perturbation. To date, there are no reports on APAs in cervical myelopathy patients, and quantification of postural control remains difficult. Thirty participants were enrolled, of which 15 were cervical myelopathy patients and 15 were normal age- and sex-matched controls. A three-dimensional motion capture system with force plates was used, and the APA phase was defined as the time between start of movement at the center of pressure and heel-off of the step leg. The APA phase (0.47 vs. 0.39 s, p < 0.05) and turning time (2.27 vs. 1.83 s, p < 0.01) were significantly longer, whereas step length tended to be shorter (305.18 vs. 361.04 mm, p = 0.06) in cervical myelopathy patients. There was a significant correlation between Japanese Orthopaedic Association lower extremity motor dysfunction scores and step length (p < 0.01). Cervical myelopathy patients are prone to falls due to longer APA phases with shorter step lengths. Analysis of the APA phase aids the visualization and quantification of postural control during initial gait in cervical myelopathy patients.

Studies in the Falls Efficacy Scale-International for patients with cervical compressive myelopathy: Reliability, validity, and minimum clinically important difference

CONTEXT

Patients with cervical compressive myelopathy (CCM) often complain of body balance problems, such as fear of falling and bodily unsteadiness. However, no accepted patient-reported outcome measures (PROMs) for this symptomatology exist. The Falls Efficacy Scale-International (FES-I) is one of the most widely used PROMs for evaluating impaired body balance in various clinical fields.

OBJECTIVE

To examine reliability, validity, and minimum clinically important difference (MCID) of the FES-I for the evaluation of impaired body balance in patients with CCM.

METHODS

Patients who underwent surgery for CCM were retrospectively reviewed. The FES-I was administered preoperatively and at 1 year postoperatively. Further, cJOA-LE score (subscore for lower extremities in the Japanese Orthopaedic Association score for cervical myelopathy) and stabilometric data, obtained at the same time points of the FES-I administration, were analyzed. Reliability was examined through internal consistency with Cronbach's alpha. Convergent validity was studied using correlation analysis. The MCID was estimated using anchor- and distribution-based methods.

RESULTS

Overall, 151 patients were included for analysis. Cronbach's alpha coefficient was the acceptable value of 0.97 at both baseline and 1 year postoperatively. As for convergent validity, the FES-I had significant correlations with the cJOA-LE score and stabilometric parameters both at baseline and 1 year postoperatively. The MCID calculated using anchor- and distribution-based methods was 5.5 and 10, respectively.

CONCLUSION

FES-I is a reliable and valid PROM to evaluate body balance problems for the CCM population. The established thresholds of MCID can help clinicians recognize the clinical significance of changes in patient status.

Analysis of Spastic Gait in Patients With Cervical Myelopathy Using the Timed Up and Go Test With a Laser Range Sensor

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

This study aimed to objectively evaluate spastic gait and reveal its novel characteristics via analysis of gait in patients with cervical myelopathy (CM) using the Timed Up and Go (TUG) test with a laser range sensor.

SUMMARY OF BACKGROUND DATA

Among patients with CM, spastic gait is a common diagnostic symptom; thus, objective assessments of spastic gait would be useful for the diagnosis of CM and recognition of disease status. Although spastic gait has been objectively evaluated in previous studies, the methods employed in those studies are not suitable for clinical settings.

METHODS

In total, 37 and 24 participants were recruited for a control group and CM group, respectively. CM was diagnosed by spine surgeons. We developed a laser TUG test, in which the position and velocity of both the legs were captured. The parameter values for both groups were statistically compared, and odds ratios were calculated using logistic regression analyses.

RESULTS

The total TUG-test time, time to stand up, time to first step, number of steps, and trajectory error for the CM group were significantly higher than those for the control group, whereas the average velocity and average stride length for the CM group were significantly lower than those for the control group. There was a significant independent association between the total TUG-test time and CM. The optimal cutoff point of the total test time for CM risk was approximately 9 seconds.

CONCLUSION

Through the use of the laser TUG test, we were able to identify characteristics of spastic gait, which leads to difficulty in standing and taking the first step, wobbling while walking, and an increased risk of falling. We found that the risk of CM was higher if the individual took longer than 9 seconds to complete the TUG test.Level of Evidence: 4.

Degenerative cervical myelopathy delays responses to lateral balance perturbations regardless of predictability

The aim of this study was to quantify balance impairments in standing in people with degenerative cervical myelopathy (PwDCM) in response to external perturbations. PwDCM have damage to their spinal cord due to degeneration of the cervical vertebral column, but little is known about balance. Balance was quantified by capturing kinetics, kinematic, and electromyographic data during standing in response to lateral waist pulls. Participants received pulls during predictable and unpredictable contexts in three stance widths at two magnitudes. In response to lateral waist pulls, PwDCM had larger center of mass excursion (P < 0.001) and delayed gluteus medius electromyography onset (P < 0.001) and peak (P < 0.001) timing. These main effects of history of myelopathy were consistent across predictability, stance width, and magnitude. A multilinear regression determined that gluteus medius peak timing + tibialis anterior peak timing most strongly predicted center of mass excursion (R² = 0.50, P < 0.001). These data suggest that PwDCM have delays in generating voluntary and reactive motor commands, contributing to balance impairments. Future rehabilitation strategies should focus on generating rapid muscular contractions. Additionally, frontal plane postural control is regulated by the gluteus medius and the tibialis anterior, whereas other muscles (e.g. gluteus minimus, ankle invertors/evertors) not studied here may also contribute.NEW & NOTEWORTHY Frontal plane reactive postural control is impaired in persons with degenerative cervical myelopathy because of delayed muscle responses. Additionally, postural control varies across stance width, predictability, and perturbation magnitude.

Grip Strength as a Screening Index for Severe Degenerative Cervical Myelopathy in Primary Care: Development of Cutoff Values Using Receiver Operating Curve Analysis

Purpose

Early diagnosis of degenerative cervical spondylosis (DCM) is desirable because late treatment can lead to irreversible sequelae. No screening method has yet been established. Grip strength is commonly used in primary care settings to evaluate disease activity and diagnose sarcopenia. This single-center, cross-sectional study aimed to determine the diagnostic accuracy of grip strength for cervical myelopathy (DCM) and cutoff values for primary care DCM screening using area under the curve (AUC) and sensitivity values.

Patients and Methods

The DCM group comprised 249 consecutive participants (165 males, 84 females; mean age, 65.1 years) with DCM who had undergone surgery at the affiliated hospital. The control group comprised 735 (280 males, 455 females; mean age, 65.8 years) participants undertaking a local government health checkup. Stratifying by age and sex, receiver operating characteristic (ROC) analyses were constructed for each group using minimum grip strength values for both hands. Based on ROC analysis, cut-off values were established so that the screening sensitivity would be 90% for either sex or age group, respectively.

Results

According to age group and sex (males/females [M/F]), AUC values for a diagnosis of DCM in M/F were as follows: 40–59 years, 0.92/0.87; 60–69 years, 0.94/0.89; 70–79 years, 0.89/0.91; and 80–89 years, 0.97/0.97. Calculated M/F cutoff values were 41/24.5, 27/16, 27/15, and 20/10 kg, which were similar to cutoff scores for sarcopenia in M/F patients aged 60–69 and 70–79 years. M/F sensitivities in each age groups were 0.94/0.91, 0.92/0.90, 0.95/0.96, and 0.92/0.93. M/F specificities were 0.62/0.59, 0.84/0.83, 0.61/0.71, and 0.83/0.88.

Conclusion

Grip strength had moderate-to-high diagnostic accuracy for DCM between participants in the control and DCM groups. We developed easily applicable cutoff values for primary care DCM screening with ≥90% sensitivity. In patients with sarcopenia, DCM should be differentially diagnosed in primary care.

Predictors of Falls in Patients with Degenerative Cervical Myelopathy: A Prospective Multi-institutional Study

STUDY DESIGN

Prospective multicenter study.

OBJECTIVES

The purpose of this study was to characterize a population of patients with degenerative cervical myelopathy (DCM) combined with a history of falling, and to identify the predictors associated with those falls.

SUMMARY OF BACKGROUND DATA

Falls among patients with DCM are common and can lead to the worsening of neurological symptoms. However, there are no prospective studies that have investigated the risk factors for falls in these patients.

METHODS

We prospectively enrolled patients scheduled for surgery for DCM and evaluated the significance of various preoperative measures for predicting falls. We then examined the correlation between the number of falls and the preoperative factors. Lastly, we performed stepwise logistic regression analysis to assess the concurrent effects of various factors on the occurrence of falls.

RESULTS

Among the 135 patients analyzed, 64 experienced one or more falls from the time of enrollment to 1 year postoperatively. Univariate analysis showed that the preoperative potassium and albumin levels, handgrip strength, and the Japanese Orthopaedic Association score for the assessment of cervical myelopathy (C-JOA score) were lower and Nurick grade was higher in the fallers group. Serum potassium level, handgrip strength, C-JOA score, Nurick grade, European Quality of Life-5 Dimensions (EQ-5D) score, t1 pelvic angle, and sagittal vertical axis had weak correlations with the number of falls. The fallers group had a lower C-JOA and EQ-5D scores and a lower recovery rate at one year postoperatively. Stepwise multiple logistic regression analysis identified preoperative potassium level and handgrip strength as the independent preoperative predictors for falling.

CONCLUSION

We identified preoperative lower serum potassium level and weaker handgrip strength as significant predictors of falls in patients with DCM. Therefore, DCM patients with these risk factors should be cautious about falls and might be candidates for immediate surgical intervention.Level of Evidence: 3.

Automated detection of cervical ossification of the posterior longitudinal ligament in plain lateral radiographs of the cervical spine using a convolutional neural network

Cervical ossification of the posterior longitudinal ligament (OPLL) is a contributing factor to spinal cord injury or trauma-induced myelopathy in the elderly. To reduce the incidence of these traumas, it is essential to diagnose OPLL at an early stage and to educate patients how to prevent falls. We thus evaluated the ability of our convolutional neural network (CNN) to differentially diagnose cervical spondylosis and cervical OPLL. We enrolled 250 patients with cervical spondylosis, 250 patients with cervical OPLL, and 180 radiographically normal controls. We evaluated the ability of our CNN model to distinguish cervical spondylosis, cervical OPLL, and controls, and the diagnostic accuracy was compared to that of 5 board-certified spine surgeons. The accuracy, average recall, precision, and F1 score of the CNN for classification of lateral cervical spine radiographs were 0.86, 0.86, 0.87, and 0.87, respectively. The accuracy was higher for CNN compared to any expert spine surgeon, and was statistically equal to 4 of the 5 experts and significantly higher than that of 1 expert. We demonstrated that the performance of the CNN was equal or superior to that of spine surgeons.

Subclinical gait disturbance and postoperative gait improvement in patients with degenerative cervical myelopathy

This study aimed to evaluate the subclinical gait abnormalities and the postoperative gait improvements in patients with degenerative cervical myelopathy using three-dimensional gait analysis. We reviewed the gait analysis of 62 patients who underwent surgical treatment for degenerative cervical myelopathy. The asymptomatic gait group included 30 patients and the gait disturbance group included 32 patients who can walk on their own slowly or need assistive device on stairs. The step width (17.2 cm vs. 15.9 cm, P = 0.003), stride length (105.2 cm vs. 109.1 cm, P = 0.015), and double-limb support duration (13.4% vs. 11.7%, P = 0.027) improved only in the asymptomatic gait group. Preoperatively, the asymptomatic gait group exhibited better maximum knee flexion angle (60.5° vs. 54.8°, P = 0.001) and ankle plantarflexion angle at push-off (− 12.2° vs. − 6.5°, P = 0.001) compared to the gait disturbance group. Postoperatively, maximum knee flexion angle (62.3° vs. 58.2°, P = 0.004) and ankle plantarflexion angle at push-off (− 12.8° vs. − 8.3°, P = 0.002) were still better in the asymptomatic gait group, although both parameters improved in the gait disturbance group (P = 0.005, 0.039, respectively). Kinematic parameters could improve in patients with gait disturbance. However, temporospatial parameters improvement may be expected when the operative treatment is performed before apparent gait disturbance.

Handgrip Strength Correlated with Falling Risk in Patients with Degenerative Cervical Myelopathy

Background: Few studies have investigated associations between hand grip strength (HGS) and the surgical outcomes of degenerative cervical myelopathy (DCM). Methods: This study was designed as a prospective observational study of 203 patients who had undergone fusion surgery for DCM. We divided the patients according to sex and HGS differences. Clinical outcome parameters, including HGS, a fall diary and four functional mobility tests (alternative step test, six-meter walk test, timed up and go test, and sit-to-stand test) were measured preoperatively, at 3 months and 1 year after surgery. Results: Mean patient ages were 59.93 years in the male group and 67.33 years in the female group (p = 0.000; independent t-test). The mean HGS of both hands improved significantly at postoperative 3 months and 1 year in all patients (p = 0.000 for both; ANOVA). In male patients, preoperative risk of falls was negatively correlated with HGS (p = 0.000). In female patients, pre- and postoperative risk of falls were correlated negatively with HGS (p = 0.000). The postoperative incidence of falls decreased in both groups (p = 0.000) Conclusions: Postoperative HGS in patients with DCM is correlated with postoperative falls and functional outcome differently, when comparing male and female patients, for predicting favorable outcomes and neurologic deficit recovery after surgery in DCM patients.

Effectiveness of Surgical Treatment for Degenerative Cervical Myelopathy in Preventing Falls and Fall-related Neurological Deterioration: A Prospective Multi-institutional Study

STUDY DESIGN

Prospective multi-center study.

OBJECTIVE

The aim of this study was to evaluate the effectiveness of surgical treatment in reducing falls and fall-related neurological deterioration in a prospective cohort of patients undergoing surgery for degenerative cervical myelopathy (DCM).

SUMMARY OF BACKGROUND DATA

Current evidence is limited for the effectiveness of surgical interventions for DCM in reducing the risk of fall-related neurological deterioration.

METHODS

Patients with DCM scheduled for surgical treatment were enrolled prospectively at eight participating institutes. At the time of enrollment, participants were given diaries to record details of their falls, to be returned at the 1-year postoperative follow-up. In the fall diary, patients were asked whether they had experienced any deterioration in neurological symptoms at each fall episode. Deterioration of neurological symptoms was categorized as follows: only deterioration of sensory function in the limbs; or deterioration of motor deficits. The incidence rate of falls was calculated separately for the preoperative and postoperative periods, as the total number of falls divided by the time over which falls were monitored (100 person-years). Functional outcome was assessed with the Japanese Orthopaedic Association (JOA) score and Neck Disability Index.

RESULTS

Of the initial 168 participants, 159 completed the 1-year follow-up, and 132 fall diaries were retrieved and analyzed. Of these 132 patients, 65 (49%) reported at least one fall during the survey period. The incidence rate of falls decreased significantly from 497.4 to 90.3 falls per 100 person-years after surgery. The incidence of motor deterioration per fall decreased significantly from 34% to 8% after surgery. Patients who experienced preoperative fall-related motor deterioration had a significantly lower JOA score compared with patients without fall-related motor deterioration at 1-year follow-up.

CONCLUSION

Surgical intervention for DCM is effective not only in reducing the frequency of falls, but also in reducing the risk of fall-related deterioration of motor deficits.

LEVEL OF EVIDENCE

2.

Fragility Fracture Risk in Elderly Patients With Cervical Myelopathy

STUDY DESIGN

Retrospective review.

OBJECTIVE

To identify and compare the incidences of fragility fractures amongst three elderly populations: the general population, patients with surgically treated cervical spondylotic myelopathy (CSM), and patients with CSM not surgically treated.

SUMMARY OF BACKGROUND DATA

CSM is a common disease in the elderly. Progression of myelopathic symptoms, including gait imbalance, can be a source of morbidity as it can lead to increased falls.

METHODS

Records of elderly patients with Medicare insurance from 2005 to 2014 were retrospectively reviewed. Three mutually exclusive populations of patients were identified for analysis, including a cohort of patients with a diagnosis of CSM who were not treated with surgery; a cohort of patients with CSM who were treated with surgery; and a group of control patients who had never been treated with cervical spine surgery nor were diagnosed with CSM. Incidence of fractures of the distal radius, proximal humerus, proximal femur, and lumbar spine were assessed and compared between cohorts, adjusted by age, sex, osteoporosis, dementia, cerebrovascular disease, and Charlson Comorbidity Index.

RESULTS

A total of 891,864 patients were identified, of which 60,332 had a diagnosis of CSM and 24,439 underwent cervical spine surgery. Compared to general population controls, the 12-month adjusted odds of experiencing at least one fragility fracture were 1.59 times higher in patients with CSM who were not treated with surgery (P < 0.001). The analogous odds ratio was 1.34 (P < 0.001) at 3 years. Compared to nonsurgically treated patients with CSM, the odds of experiencing at least one fragility fracture were reduced to 0.89 in surgically treated patients (P = 0.008).

CONCLUSION

Fragility fractures are a significant source of morbidity and mortality in elderly patients. CSM is associated with increased rates of fragility fractures, although surgical management of CSM may be protective against risk of fragility fracture.

LEVEL OF EVIDENCE

3.

The 25-question Geriatric Locomotive Function Scale predicts the risk of recurrent falls in postoperative patients with cervical myelopathy

BACKGROUND

Fall-induced injuries represent a major public health concern for older individuals. The relationship between risk of falling and the severity of locomotive syndrome (LS) remains largely unknown.

METHODS

We conducted a retrospective analysis of patients who had undergone surgery from January 2012 to December 2013 and completed at least 1 year of follow-up at 12 participating institutes. Patients completed a questionnaire survey regarding their fall experience during a routine postoperative follow-up. Questionnaire items included the number of falls during the prior postoperative year and the 25-question Geriatric Locomotive Function Scale (GLFS-25). The severity of cervical myelopathy was assessed using the Japanese Orthopaedic Association (JOA) score. We analyzed the association between the incidence of falling and the severity of LS measured by the GLFS-25.

RESULTS

Of 360 patients, 61 (16.9%) experienced 1 fall; 31 (8.6%), 2-3 falls; 4 (1.1%), 4-5 falls; and 6 (1.7%), ≥6 falls during the first postoperative year. Thus, 102 (28%) patients experienced at least 1 fall, and 41 (11%) experienced recurrent falls (2 or more falls) during the time period. The mean GLFS-25 score was 30.2 ± 22.7, and 242 (62%) patients had GLFS-25 scores of 16 or higher, which fulfilled the diagnostic criteria for LS. When subjects were categorized into recurrent fallers and non-recurrent fallers, recurrent fallers had a significantly higher GLFS-25 score and a significantly lower extremity motor function score of the JOA score than non-recurrent fallers. The GLFS-25 and lower extremity motor function score of the JOA score yielded the areas under the receiver operating characteristic curves of 0.674 and 0.607, respectively, to differentiate recurrent fallers from non-recurrent fallers.

CONCLUSION

Postoperative patients with cervical myelopathy had a 62% prevalence of LS. The GLFS-25 may be useful to predict the risk of recurrent falls in patients with cervical myelopathy.