Neuroradiologic and electrophysiologic assessment of cervical spondylotic amyotrophy

Additional benefit of ultrasonography to evaluate nerve root condition of degenerative cervical spine disease

STUDY DESIGN

A cross-sectional explanatory study.

OBJECTIVES

To clarify the nerve root condition and the association between nerve root cross-sectional area (CA) on ultrasonography (US) and other examinations such as MRI or compound muscle action potentials (CMAPs) in degenerative cervical spine diseases.

SETTING

A university hospital in Japan.

METHODS

Fifty-one patients diagnosed with proximal cervical spondylotic amyotrophy (CSA) (13 patients), cervical radiculopathy of C5 or C6 nerve root (CR) (26 patients), or cervical spondylotic myelopathy (CSM) (12 patients), and twenty-nine healthy volunteers were included in this study. Neurological findings, US findings and CMAPs of deltoid and biceps muscles of all participants were evaluated. In addition, CSA, CR, and CSM patients underwent MRI.

RESULTS

A significant correlation was not observed between CA and CMAP amplitude or foraminal diameter on MRI (P > 0.05). In the US examination, the C6 CA of the affected side of the CR group was significantly larger than that of both the normal side and the other groups (P < 0.001). The C5 CA of the affected side of the CSA group clearly showed a bimodal distribution: enlarged and small CA groups. In the CMAP findings, CSA cases respectively showed the lower amplitude of deltoid and bicep CMAPs on both the normal and the affected side (P ≦ 0.01). CSM and healthy volunteers were nearly identical in CA and CMAPs.

CONCLUSION

Utilizing US in addition to NCS and MRI can contribute towards an evaluation of the nerve root condition of degenerative cervical spine disease.

SPONSORSHIP

no sponsorship.

Alteration of muscle activity during voluntary rehabilitation training with single-joint Hybrid Assistive Limb (HAL) in patients with shoulder elevation dysfunction from cervical origin

Shoulder elevation, defined here as arm raising, being essential for activities of daily living, dysfunctions represent a substantial burden in patients' lives. Owing to the complexity of the shoulder joint, the tightly coordinated muscular activity is a fundamental component, and neuromuscular impairments have devastating effects. A single-joint shoulder type version of the Hybrid Assistive Limb (HAL) allowing motion assistance based on the intention of the user via myoelectric activation has recently been developed, and its safety was demonstrated for shoulder rehabilitation. Yet, little is known about the physiological effects of the device. This study aims to monitor the changes in muscle activity and motion during shoulder HAL rehabilitation in several patients suffering from shoulder elevation dysfunction from cervical radicular origin. 8 patients (6 males, 2 females, mean age 62.4 ± 9.3 years old) with weakness of the deltoid muscle resulting from a damage to the C5 nerve root underwent HAL-assisted rehabilitation. We combined surface electromyography and three-dimensional motion capture to record muscular activity and kinematics. All participants showed functional recovery, with improvements in their Manual Muscle Testing (MMT) scores and range of motion (ROM). During training, HAL decreased the activity of deltoid and trapezius, significantly more for the latter, as well as the coactivation of both muscles. We also report a reduction of the characteristic shrugging compensatory motion which is an obstacle to functional recovery. This reduction was notably demonstrated by a stronger reliance on the deltoid rather than the trapezius, indicating a muscle coordination tending toward a pattern similar to healthy individuals. Altogether, the results of the evaluation of motion and muscular changes hint toward a functional recovery in acute, and chronic shoulder impairments from cervical radicular origin following shoulder HAL rehabilitation training and provide information on the physiological effect of the device.

Prognostic factors for neurological outcome after anterior decompression and fusion for proximal-type cervical spondylotic amyotrophy - A retrospective analysis of 77 cases

BACKGROUND

Decompression through an anterior approach is theoretically effective for the surgical treatment of cervical spondylotic amyotrophy (CSA), because the pathology usually locates at the anterior side. However, most previous studies investigated posterior surgery or a mix of anterior surgery and posterior surgery in their investigation. Only a few small case series have investigated the surgical outcomes of anterior decompression and fusion (ADF). Therefore, we conducted a multicenter retrospective study that included patients who underwent ADF for proximal-type CSA.

METHODS

We analyzed the outcomes of 77 consecutive spinal surgeries performed on proximal-type CSA patients who underwent ADF. Preoperative and postoperative manual muscle tests (MMT) and the patients' backgrounds, radiological findings, and complications were reviewed. We divided the cases into two groups, good-outcome group (MMT improvement ≧ 2 or improved to MMT 5) and poor-outcome group (others) and evaluated the prognostic factors for outcomes.

RESULTS

Of the 77 patients, 48 (62%) showed good neurological outcome. Multiple compressive lesions at anterior horn (AH) and/or ventral nerve roots (VNRs) were detected in 66 patients (85.7%) on the magnetic resonance images. The patients with a single compressive lesion at VNR or AH tended to show good neurological recovery when compare to those with multiple lesions. Age and duration of symptoms were related to the poor outcome in univariate analysis. Duration of symptoms was an independent factor associated with postoperative neurological outcome. The cut-off value for poor outcome was 7.0 months for the symptom duration (sensitivity: 79%, specificity: 54%, area under the curve: 0.69).

CONCLUSIONS

Patients with proximal-CSA were more likely to have multiple compressive lesions at an AH and/or a VNR. The prognostic factor for poor neurological outcome was duration of symptoms of ≥7 months.

Atypical Proximal Cervical Spondylotic Amyotrophy: Case Report Demonstrating Clinical/Imaging Discrepancy

Purpose

The aim of this study was to present a novel case of unilateral proximal cervical spondylotic amyotrophy (CSA) with contralateral spinal cord compression, which is subject to misdiagnosis and missed diagnosis.

Background

CSA is the rare form of cervical spondylosis, which is characterized by severe muscle atrophy in the upper extremities. It can be classified in the proximal subtype and the distal subtype. The etiology, pathophysiology and treatment of CSA are still controversial.

Methods

A rare case of atypical proximal CSA, who presented with left shoulder and arm weakness, but cervical magnetic resonance imaging (MRI) showed large right paracentral disc herniation in the C4-5 level. Twelve weeks after undergoing anterior cervical discectomy and fusion technique in C4-5 level, the patient’s symptoms obviously recovered.

Conclusion

The opposite sides between disc herniation and clinical symptoms of upper extremity may be attributed to C5 ventral rootlet becoming stretched caused by spinal cord rotation or shift to the opposite side.

Evaluation of Anterior Decompression Surgical Outcomes of Proximal-Type Cervical Spondylotic Amyotrophy: A Retrospective Study

OBJECTIVE

To investigate the efficiency of anterior decompression on the proximal-type cervical spondylotic amyotrophy patients.

METHODS

This was a retrospective analysis. From January 2014 to November 2017, 21 patients with proximal-type cervical spondylotic amyotrophy (CSA) underwent anterior decompression. There were 15 males and 6 females, aged 35-73 years with an average of 51.62 years. All the patients underwent surgery of anterior decompression (ACDF or ACCF). Among them, 12 patients underwent C_4/5 single level ACDF, eight patients underwent C_4/5 and C_5/6 double level ACDF, and one patient underwent C5 anterior cervical corpectomy decompression and fusion surgery. Preoperative and postoperative clinical and radiologic parameters were assessed. The clinical examinations were reviewed, including muscle strength, neck disability index (NDI) score, cervical Japanese Orthopaedic Association (JOA) score, and improvement rate of manual muscle test (MMT) at the last follow-up. Preoperative spinal cord or nerve impingement was assessed by magnetic resonance imaging (MRI) or computed tomography (CT) myelography. Postoperative lateral X-ray radiographs were performed every 3 months after the surgery.

RESULTS

Severe preoperative muscle atrophy of the deltoid or biceps muscles occurred in 21 patients included in the study. All of them involve impingements of the ventral nerve root and/or the anterior horn according to MRI and CT myelography. The preoperative duration of symptoms averaged 8.4 months. The average follow-up for all patients was 13.2 months. At the final follow-up, all patients showed statistically significant improvements in muscle strength and NDI scores (P < 0.05, P < 0.05). For the deltoid muscles force and C-JOA scores, the average improvement rates were 66.49% ± 10.04% and 62.23% ± 9.23%, respectively. With respect to MMT, 12 proximal-type patients were graded excellent, six were good, and three were fair, and the overall improvement rate was 85.7%.

CONCLUSIONS

For proximal-type CSA patients with cervical radiculopathy, earlier anterior decompression surgery can achieve satisfactory results by significantly improving a patient's muscle strength and relieving compression symptoms.

Cervical Spondylotic Amyotrophy: Case Series and Review of the Literature

OBJECTIVE

Cervical spondylotic amyotrophy (CSA) is a relatively rare entity caused by cervical degenerative spinal diseases and characterized by motor weakness accompanied by remarkable muscle atrophy in the upper extremities without significant sensory deficits or spastic paraparesis in the lower extremities. Postoperative outcomes and predictive prognostic factors vary among previous reports. In the present report, we describe the surgical results in patients who were surgically treated for CSA and present a literature review.

METHODS

In total, 33 patients with CSA were retrospectively analyzed. Correlations between the surgical outcome and the following factors were statistically analyzed: age, sex, type of impaired muscle, preoperative severity of motor weakness, number of levels of cord or root compression, presence of a T2 high-intensity area in the spinal cord, cervical kyphosis, and methods of surgical procedure.

RESULTS

On postoperative neurological evaluation, 25 patients (75.8%) had favorable outcomes and 8 had unfavorable outcomes (proximal type, 72.2%; distal type, 78.6%). Patients with favorable outcomes were significantly younger than those with unfavorable outcomes (p=0.013). Patient's characteristics except for age and radiological factors were not correlated to surgical outcome.

CONCLUSION

The present study focused on the surgical results in patients who were surgically treated for CSA along with updated information from a literature review. Improvement of motor weakness is expected with acceptable prevalence although higher age can be a negative factor. Surgical outcomes and predictive factors related to a poor prognosis were determined and compared with those of previous articles.

Surgical outcomes for distal-type cervical spondylotic amyotrophy: a multicenter retrospective analysis of 43 cases

PURPOSE

Distal-type cervical spondylotic amyotrophy (CSA) is a rare form of cervical spondylosis that causes muscle weakness of upper extremities. The pathophysiology and appropriate surgical method for the treatment of CSA are still controversial. We investigated clinical outcomes in surgically treated distal-type CSA.

METHODS

The authors executed an analysis of the outcomes of 43 consecutive spinal surgeries performed in distal-type CSA patients. The duration of symptoms, perioperative manual muscle test (MMT) results, radiological findings, and perioperative complications were reviewed. We compared surgical outcomes between different approaches and examined the factors related to poor outcomes (MMT improvement ≤ 0) after surgery.

RESULTS

The pathophysiology of CSA was mostly caused by a combination of multiple lesions in the anterior horn and/or nerve root. Nineteen of 29 patients (65.5%) who received anterior approach methods were included in the good outcome group (MMT improvement ≥ 1), whereas 7 of 14 patients (50.0%) in the posterior group were classified as good. In the anterior group, the mean MMT grade significantly improved from 2.6 to 3.4 (p = 0.0035) despite the higher rate of complications. The duration of symptoms was substantially associated with poor outcomes. The MMT grade significantly improved from 2.2 to 3.2 (p = 0.0118) in the < 6 months group. Cervical alignments and preoperative MMT grade were not statistically associated with poor outcomes.

CONCLUSIONS

Patients with poor outcomes had symptoms for a longer duration. We found tolerable clinical outcomes within 6 months from onset. The anterior approaches might be recommended because this procedure significantly improved MMT levels in the hands. These slides can be retrieved under Electronic Supplementary Material.

Cervical spondylotic amyotrophy: a systematic review

PURPOSE

Cervical spondylotic amyotrophy (CSA) is characterized by upper limb muscle weakness and atrophy, without sensory deficits. The pathophysiology of CSA has been attributed to selective injury to the ventral nerve root and/or anterior horn of the spinal cord. This review aimed to delineate the history of CSA and to describe the epidemiology, etiology, pathophysiology, classification, clinical features, radiological and electrophysiological assessment, diagnosis, differential diagnosis, natural history and treatment of CSA.

METHODS

A comprehensive search of PubMed, EMBASE, Cochrane library and Web of Science databases was conducted, from their inception to April 3, 2018.

RESULTS

Clinically, CSA is classified into three types: a proximal-type (involving the scapular muscles, deltoid and biceps), a distal-type (involving the triceps and muscles of the forearm and hand) and a diffuse-type (involving features of both the distal- and proximal-type). Diagnosis requires documentation of muscle atrophy, without significant sensory deficits, supported by careful neurological, radiological and neurophysiological assessments, with amyotrophic lateral sclerosis, Parsonage-Turner syndrome, rotator cuff tear and Hirayama disease being the principle differential diagnoses. Conservative management of CSA includes cervical traction, neck immobilization and physical therapy, with vitamin B12 or E administration being useful in some patients. Surgical treatment, including anterior decompression and fusion or laminoplasty, with or without foraminotomy, is indicated after conservative treatment failure. Factors associated with a poor outcome include the distal-type CSA, long symptom duration, older age and greater preoperative muscle weakness.

CONCLUSION

Although the disease process of CSA is self-limited, treatment remains challenging, leaving scope for future studies. These slides can be retrieved under Electronic Supplementary Material.

Changes in Central Motor Conduction Time and Its Implication on Dysfunction of Distal Upper Limb in Distal-Type Cervical Spondylotic Amyotrophy

PURPOSE

Distal-type cervical spondylotic amyotrophy (CSA) is an uncommon syndrome associated with cervical spondylosis. The pathogenic mechanism of distal-type CSA is still unclear. The aim of the current study was to analyze central motor conduction time (CMCT) in the cases with distal-type CSA and to investigate the role of cervical cord compressive injury in the distal-type CSA.

METHODS

Both 28 cases with distal-type CSA and 21 healthy subjects accepted CMCT measures, motor unit number estimation, handgrip strength examination, and magnetic resonance imaging evaluation.

RESULTS

In this study, nine (9/28, 32.1%) cases with CSA presented with prolonged CMCT, and both reduced number of motor units and decreased handgrip strength were found in these 9 cases (P < 0.05). Magnetic resonance imaging evaluation showed that 7 of these 9 patients presented with proximal cervical cord compression with or even without distal selective compression consistent with segmental atrophy. A negative relationship between CMCT and both number of motor units and handgrip strength was found on the symptomatic side (P < 0.05), and there was a positive correlation between CMCT and amplitude of single motor unit potentials on the less symptomatic side (P < 0.05).

CONCLUSIONS

Corticospinal tract damage caused by proximal spinal cord compression may induce distal motor unit loss to worsen in some cases with distal-type CSA, which may contribute to the dysfunction of the distal upper limb in some cases with distal-type CSA. Therefore, treatment and rehabilitation efforts should account for both distal selective compression and proximal cord compression in distal-type CSA.

Clinical Features and Long-Term Surgical Outcomes of Patients with Cervical Spondylotic Amyotrophy

BACKGROUND

Cervical spondylotic amyotrophy (CSA) is not common. The clinical features and long-term surgical outcomes of patients with CSA are also unclear. We sought to summarize clinical features, assess long-term surgical outcomes, and determine the prognostic factors relevant for patients with CSA.

METHODS

A total of 136 patients with CSA who underwent anterior or posterior decompression during January 2001 to December 2012 were included. Their clinical and radiologic data were collected. The surgical outcome was evaluated using manual muscle test and improvements in the muscle strength. Correlations between the surgical outcome and various factors also were analyzed.

RESULTS

In total, 128 patients underwent anterior decompression and 8 patients underwent posterior decompression. At the final follow-up, the surgical outcome was significantly better after anterior decompression compared with that after posterior decompression. Statistical analyses showed the type of CSA, duration of symptoms, and association with ossification of the posterior longitudinal ligament were associated with a poor outcome after anterior surgery (P < 0.05).

CONCLUSIONS

Besides significant muscular atrophy in one upper extremity, CSA also occasionally presents with mild atrophy in the other upper extremity, sensory disturbance in the upper extremities, or hyperflexia in the lower extremities. Anterior decompression is generally effective in the treatment of patients with CSA. Preoperative duration of symptoms, type of CSA, and ossification of the posterior longitudinal ligament are important predictors for the surgical outcome.

Influences of different lower cervical bone graft heights on the size of the intervertebral foramen: multiple planar dynamic measurements with laser scanning

The aim of this study is to evaluate the influences of different bone graft heights on the size of the intervertebral foramen, which will help determine the optimal graft height in clinical practice. Six fresh adult cadavers were used, with the C5-C6 vertebral column segment defined as the functional spinal unit (FSU). After discectomy, the C5/6 intervertebral height was set as the baseline height (normal disc height). We initially used spiral computed tomography (CT) to scan and measure the middle area of the intervertebral foramen when at the baseline height. Data regarding the spatial relationship of C5-C6 were subsequently collected with a laser scanner. Grafting with four different sized grafts, namely, grafts of 100, 130, 160, and 190% of the baseline height, was implanted. Moreover, we scanned to display the FSU in the four different states using Geomagic8.0 studio software. Multiple planar dynamic measurements (MPDM) were adopted to measure the intervertebral foramen volume, middle area, and areas of internal and external opening. MPDM with a laser scanner precisely measured the middle area of the intervertebral foramen as spiral CT, and it is easy to simulate the different grafts implanted. With the increase of the bone graft height, the size of the intervertebral foramen began to decrease after it increased to a certain point, when grafts of 160% of the baseline height implanted. MPDM of the intervertebral foramens with laser scanning three-dimensional (3D) reconstitution are relatively objective and accurate. The recommended optimal graft height of cervical spondylosis is 160% of the mean height of adjacent normal intervertebral spaces.

Evidence that impaired motor conduction in the bilateral ulnar and tibial nerves underlies cervical spondylotic amyotrophy in patients with unilateral deltoid muscle atrophy

Introduction

The clinical entity of cervical spondylotic amyotrophy (CSA) is characterized by severe muscle atrophy in the upper extremities with insignificant sensory deficits in patients with cervical spondylosis. However, the pathogenesis of CSA is still unclear.

Methods

We assessed electrophysiological motor conduction through the corticospinal tract and ulnar and tibial nerves, which do not supply the deltoid or biceps muscles, of 18 patients with CSA, 12 patients with compressive cervical myelopathy, and 18 control subjects with cervical spondylotic radiculopathy. Motor evoked potentials following transcranial magnetic stimulation and M-waves and F-waves following electrical stimulation were measured from the bilateral abductor digiti minimi muscles (ADMs) and abductor hallucis muscles (AHs). The peripheral conduction time (PCT) was calculated from the latencies of the CMAPs and F-waves as follows: (latency of CMAPs + latency of F-waves - 1) / 2. The central motor conduction time (CMCT) was calculated by subtracting the PCT from the onset latency of the MEPs.

Results

The M-wave (M) latency and minimum F-wave (Fmin) latency from the ADM, and Fmin-M latency from the ADM/AH were significantly longer in the CSA group than in the other groups, on both the affected (p = 0.000-0.007) and unaffected sides (p = 0.000-0.033). F-wave persistence from the bilateral ADMs was significantly lower in the CSA group than in the other groups (p = 0.000-0.002). Among the CSA patients, there were no significant differences in these parameters between the affected and unaffected sides. The CMCT showed no significant differences between the CSA and control groups, but significant differences between the CSA and CCM groups (p = 0.000-0.004).

Conclusions

CSA patients with unilateral deltoid muscle atrophy had subclinical impairments of lower motor neurons and/or peripheral axons in the ulnar nerve, and subclinical impairments of peripheral axons in the tibial nerve. These motor impairments may have originally existed in these individuals before the onset of CSA.

Predisposing factors for poor outcome of surgery for cervical spondylotic amyotrophy: a multivariate analysis

The purpose of this study was to characterize risk factors for poor surgical outcome in patients with cervical spondylotic amyotrophy (CSA). We retrospectively reviewed 88 cases of CSA surgery and investigated age, sex, duration of symptoms, atrophy type, preoperative muscle power, signal changes on MRI, anterior horn (AH) or ventral nerve root (VNR) compression, compression levels, surgical approach and postoperative recovery. Fifty (56.8%) patients had good surgical outcome. Logistic regression, with poor outcome as dependent variable, showed independent risks associated with duration of symptoms (OR; 1 for symptom duration less than 3 months versus 3.961 [95% CI; 1.203–13.039, p = 0.024] for symptom duration of 3–6 months versus 18.724 [95% CI; 3.967–88.367, p < 0.001] for symptom duration greater than 6 months), compression type (OR; 1 for VNR versus 4.931 [95% CI; 1.457–16.685, p = 0.010] for AH versus 5.538 [95% CI; 1.170–26.218, p = 0.031] for VNR + AH), and atrophy type (OR; 1 for proximal type versus 6.456 [95% CI; 1.938–21.508, p = 0.002] for distal type). These findings suggest that a long duration of symptoms, AH or both AH and VNR compression, and distal type are risk factors for poor surgical outcome in patients with CSA.

Evaluation of characteristics and surgical outcomes in cervical spondylotic amyotrophy

BACKGROUND

Cervical spondylotic amyotrophy (CSA) is a rare clinical syndrome resulting from cervical spondylosis. Surgical treatment includes anterior cervical decompression and fusion (ACDF), and laminoplasty with or without foraminotomy. Some studies indicate that ACDF is an effective method for treating CSA because anterior decompression with or without medial foraminotomy can completely eliminate anterior and/or anterolateral lesions. We retrospectively evaluated outcome of surgical outcome by anterior cervical decompression and fusion (ACDF).

MATERIALS AND METHODS

28 CSA patients, among whom 12 had proximal type CSA and 16 had distal type CSA, treated by ACDF, were evaluated clinicoradiologically. The improvement in atrophic muscle power was assessed by manual muscle testing (MMT) and the recovery rate of the patients was determined on the basis of the Japanese Orthopedic Association (JOA) scores. Patient satisfaction was also examined.

RESULTS

The percentage of patients, who gained 1 or more grades of muscle power improvement, as determined by MMT, was 91.7% for those with proximal type CSA and 37.5% for those with distal type CSA (P < 0.01). The JOA score-based recovery rates of patients with proximal type and distal type CSA were 60.8% and 41.8%, respectively (P < 0.05). Patient satisfaction was 8.2 for those with proximal type CSA and 6.9 for those with distal type CSA (P < 0.01). A correlation was observed among the levels of improvement in muscle power, JOA score based recovery rate, patient satisfaction and course of disease (P < 0.05).

CONCLUSION

ACDF can effectively improve the clinical function of patients with CSA and result in good patient satisfaction despite the surgical outcomes for distal type CSA being inferior to those for proximal type CSA. Course of disease is the fundamental factor that affects the surgical outcomes for CSA. We recommend that patients with CSA undergo surgical intervention as early as possible.

Minimum invasive posterior decompression for cervical spondylotic amyotrophy

BACKGROUND

Cervical spondylotic amyotrophy (CSA), characterized by amyotrophy and muscular weakness of the upper limbs, is caused by damage to anterior spinal root or anterior horn of the spinal cord. Formerly, anterior decompression and fusion were performed for treatment of CSA, but it has recently been reported that posterior decompression is also effective. However, a consensus on the choice of procedure has not yet been reached. Selective laminoplasty as minimally invasive surgery is a posterior decompression procedure that alleviates axial neck pain. Because, for CSA patients, the responsible lesion level is localized, this procedure combined with foraminotomy enables simultaneous spinal cord and root decompression. Therefore, we report the results of this treatment for CSA.

METHODS

Subjects were 28 patients (25 males, 3 females), average age 50.6 years and average follow-up 43.5 months. The muscles involved were deltoid for 14 patients, biceps for 11, and extensor digitorum communis and/or intrinsic muscles of the hand for 9. MMT scores were grade 2 for 23 cases and grade 3 for 5 cases. To evaluate the results of minimally invasive surgery, cervical ROM (C2-7) and postoperative neck pain (VAS) on the first postoperative day and 1 week after surgery were evaluated.

RESULTS

Muscle strength improvement was rated as "excellent" for 18 patients, "good" for 9, and "fair" for 1, with none rated "poor". Four of 10 patients whose muscle strength did not fully improve had distal type CSA and/or had preoperative MMT scores of 2. Average %ROM was 91.2 % and almost complete cervical ROM was maintained. The average postoperative VAS score was 2.6 on the first postoperative day and 1.2 1 week after surgery.

CONCLUSIONS

Selective laminoplasty with segmental decompression is advantageous for minimizing postoperative neck pain and for simultaneous decompression of the affected spinal cord segment and nerve root.

Anterior decompression in the management of unilateral cervical spondylotic amyotrophy

Cervical spondylotic amyotrophy is a rare clinical condition. The purpose of this study was to investigate the effects of anterior decompression in patients with unilateral upper-extremity amyotrophy caused by cervical spondylosis. The authors retrospectively analyzed the records of 31 patients (23 men and 8 women) who underwent anterior decompressive surgery for cervical spondylotic amyotrophy at the authors' institution between 2000 and 2011. Demographic characteristics, pre- and postoperative results of imaging studies, and postoperative muscle power improvement were reviewed at a mean follow-up of 22.2 months (range, 14-36 months). Patients were divided into proximal (n=21) and distal (n=10) types according to the most severely atrophic muscle, and the 2 groups were compared statistically. The most commonly affected intervertebral level in proximal-type patients was C4-C5, whereas that in distal-type patients was C5-C6. Impingements against the ventral nerve root and anterior horn were observed in 22 and 25 cases, respectively, with 16 cases having both impingements. Eighty-one percent of proximal-type patients gained 1 or more grades of muscle power improvement on manual muscle testing, whereas 40% of distal-type patients improved. Within 15 postoperative days, 57% of proximal-type patients attained subjective or objective improvement of muscle power, whereas all distal-type patients failed to improve. Anterior decompression was effective for most patients with unilateral cervical spondylotic amyotrophy, although postoperative muscle power improvement in distal-type patients was inferior to that in proximal-type patients. Furthermore, compared with the proximal type, the distal type showed a slower postoperative recovery.

Prediction of surgical outcome for proximal-type cervical spondylotic amyotrophy novel mode of assessment using compound action potentials of deltoid and biceps brachii and central motor conduction time

STUDY DESIGN

Case studies of patients with cervical spondylotic amyotrophy used compound muscle action potentials (CMAPs) of deltoid and biceps brachii muscles and central motor conduction time (CMCT).

OBJECTIVE

To discuss surgical outcome for proximal-type cervical spondylotic amyotrophy in the context of results obtained with CMAPs and CMCT.

SUMMARY OF BACKGROUND DATA

There have been no reports that correlate surgical outcome with CMAPs of deltoid and biceps brachii muscles or with CMCT.

METHODS

A retrospective study was performed for 24 patients with proximal-type cervical spondylotic amyotrophy who underwent surgical treatment of the cervical spine. Erb-point-stimulated CMAPs were recorded in the deltoid and biceps. The percent amplitude of CMAPs was calculated in comparison with the opposite side. Motor-evoked potentials were recorded from bilateral abductor digiti minimi. CMAPs and F waves were recorded after supramaximal electric stimulation of ulnar nerves. CMCT was calculated as follows: motor-evoked potentials latency - (CMAPs' latency + F latency - 1)/2 (ms). Muscle strength was evaluated using manual muscle testing. Improvements in strength were classified as excellent, good, or fair.

RESULTS

The improvement was graded as excellent in 12 cases, good in 2 cases, and fair in 10 cases. The average percentage for CMAPs' amplitude on the affected side compared with the normal side in deltoid and biceps brachii muscles was significantly different between the excellent and fair patient groups. The CMCT on the affected side was not significantly different between excellent and fair patient groups.

CONCLUSION

The average percentage range of deltoid and biceps brachii muscle CMAPs' amplitude determined at the onset of illness correlated significantly with postoperative recovery. Surgical intervention of the cervical spine should be performed in patients in whom the average percentage of CMAPs' amplitude in deltoid and biceps brachii muscles ranges from 30% to 50%.

Clinical outcomes and predictive factors relating to prognosis of conservative and surgical treatments for cervical spondylotic amyotrophy

STUDY DESIGN

Retrospective clinical analyses of patients with cervical spondylotic amyotrophy (CSA).

OBJECTIVE

To report the clinical outcomes and predictive factors relating to the prognosis in conservative and surgical treatments for CSA.

SUMMARY OF BACKGROUND DATA

CSA is a clinical entity characterized by muscle atrophy in the upper extremity without marked sensory disturbance or spastic tetraparesis. The indications for, and outcomes of conservative and surgical treatments for CSA have not been clearly enunciated.

METHODS

Ninety patients with CSA were enrolled in this study. All of them initially received continuous cervical traction for 2 to 3 weeks as inpatients. If this conservative treatment was ineffective, surgical intervention was carried out after informed consent was obtained. We investigated the outcome of conservative treatment, the predictive factors relating to the prognosis of the conservative treatment, and the outcome of surgery after initial conservative treatment failed.

RESULTS

After initial conservative treatment, 42 patients (46.7%) showed excellent or good outcome, 29 patients underwent surgery, and 19 patients declined surgery. Consequently, 61 patients were conservatively followed up. At final follow-up, 40% of the patients still showed excellent or good neurologic status by conservative treatment, and this group was characterized by age <50 years, duration of symptoms <6 months, single-level stenosis, foraminal stenosis, and a good response to traction therapy. Additional 5 patients underwent surgery during follow-up because of deterioration of symptom, and 34 patients consequently underwent surgery at the final follow-up. Of 34, 28 (82%) patients who underwent surgery obtained neurologic improvement.

CONCLUSION

The present study has demonstrated the outcome of conservative and of surgical treatments for CSA, together with the predictive factors relating to the prognosis. Conservative treatment should be initially tried on CSA patients, especially those with predictive factors relating to a better prognosis. However, if conservative treatment failed, surgical intervention was successful.

Cervical spondylotic amyotrophy

Cervical spondylotic amyotrophy is characterized with weakness and wasting of upper limb muscles without sensory or lower limb involvement. Two different mechanisms have been proposed in the pathophysiology of cervical spondylotic amyotrophy. One is selective damage to the ventral root or the anterior horn, and the other is vascular insufficiency to the anterior horn cell. Cervical spondylotic amyotrophy is classified according to the most predominantly affected muscle groups as either proximal-type (scapular, deltoid, and biceps) or distal-type (triceps, forearm, and hand). Although cervical spondylotic amyotrophy always follows a self-limited course, it remains a great challenge for spine surgeons. Treatment of cervical spondylotic amyotrophy includes conservative and operative management. The methods of operative management for cervical spondylotic amyotrophy are still controversial. Anterior decompression and fusion or laminoplasty with or without foraminotomy is undertaken. Surgical outcomes of distal-type patients are inferior to those of proximal-type patients.

Bilaterally symmetric cervical spondylotic amyotrophy: a novel presentation and review of the literature

BACKGROUND

Cervical spondylotic amyotrophy (CSA) is considered a syndrome of (1) unilateral upper extremity weakness and atrophy, (2) affecting either the proximal or distal musculature, (3) without sensory impairment or lower extremity dysfunction.

AIMS OF STUDY

The authors report a novel case of bilaterally symmetric CSA with blurring of the proximal-distal distinction, discuss the pathophysiology, and review the literature.

METHODS

A 45 year old man presented with a several year history of insidiously progressive bilaterally symmetric upper extremity weakness and wasting, profound in the proximal musculature and moderate to severe in the distal muscle groups.

RESULTS

Based on the clinical, neuroimaging and electrodiagnostic features, this patient harbors a more severe phenotype of the classical syndrome.

CONCLUSION

The authors propose expanding the generally accepted definition of CSA to include this bilaterally symmetric form of disease, thereby minimizing diagnostic error or delay. Additionally, based on this case and a review of the literature, adherence to the proximal-distal distinction should be avoided since it is commonly blurred. Accurate diagnosis is crucial since this presentation mimics the motor neuron disease variant Vulpian-Bernhardt syndrome. The importance of early diagnosis is underscored by reports of significant improvement with timely surgical decompression.

Cervical spondylotic amyotrophy presenting as dropped head syndrome

We report a case of acute-onset dropped head syndrome in a 65-year-old patient in whom the diagnosis of amyotrophic lateral sclerosis (ALS) was initially proposed based on electromyographic signs of neck and shoulder muscle denervation. There were no signs of pyramidal involvement and the clinical and electromyographic signs of motor denervation never evolved beyond the neck and shoulder girdle muscles after a 6-year follow-up period, which argued against ALS. Other causes of dropped head syndrome were carefully ruled out based on clinical findings, electrodiagnostic studies and blood investigations. The restriction of muscle denervation to a few cervical myotomes, the presence of C3-C4 spondylotic changes without associated root or spinal cord compression, and the absence of an alternative explanation to the patient's symptoms strongly supported the diagnosis of cervical spondylotic amyotrophy (CSA). CSA is thought to result from spinal cord microcirculatory disturbances and secondary anterior horn cell degeneration due to ischemia. Our case enlarges the clinical spectrum of focal cervical anterior horn disease, which classically results in more distal monomelic atrophy affecting one or both upper limbs.

Distal-type cervical spondylotic amyotrophy: incidence and outcome after central corpectomy

OBJECT

Distal-type cervical spondylotic amyotrophy (CSA) is a rare form of cervical spondylotic myelopathy (CSM). The authors documented the incidence, clinical presentation, radiological features, and outcome following central corpectomy (CC) in patients with this entity.

METHODS

The authors performed a retrospective institutional database search of patients who underwent decompressive surgery for CSM between 1992 and 2006 to identify patients with distal-type CSA. Distal-type CSA was defined as weakness and wasting of hands and forearms without gait impairment (Nurick Grades 0 and 1) nor any sensory symptoms or signs in the lower limbs.

RESULTS

The authors identified 7 male patients (1.1%) with distal-type CSA from among 653 patients who underwent either cervical laminectomy (135 patients) or CC (518 patients). There were sensory symptoms or signs in the upper limbs in all but 1 of the patients. Increased signal intensity in the cord was demonstrated on T2-weighted MR images in all patients. The compression was mainly at the C-6 vertebral level. At a mean follow-up of 46.5 months (range 12-98 months), 6 patients had improved by a mean patient perceived outcome score of 66.7% (range 20-100%). Patients' modified Japanese Orthopedic Association scores improved from a preoperative mean (+/- SD) of 16.1 +/- 0.7, to a follow-up mean of 17.4 +/- 0.5 (p = 0.004, paired t-test). One patient whose condition worsened 7 months after CC received a diagnosis of a coexistent motor neuron disease.

CONCLUSIONS

Distal-type CSA is a rare form of CSM that should be differentiated from motor neuron disease on the basis of subtle sensory symptoms or signs in the upper limbs, and the presence of significant cord compression on the MR imaging. Patient outcome after central corpectomy is good and long lasting.

Radiculopathy at the C5/6 intervertebral foramen resulting in isolated atrophy of the deltoid: an aberrant innervation complicating diagnosis. Report of two cases

We present two cases in which the diagnosis was complicated by the presence of a weak muscle innervated by a compressed motor root in the intervertebral foramen (IVF) at an atypical level. The patients were 59- and 53-year-old men; they presented with marked atrophy and weakness predominantly in a unilateral deltoid. Neuroimaging revealed narrowing of the nerve root sleeve at the C5/6 IVF due to a herniated disk or osteophyte. Predominant atrophy and weakness of the deltoid were not consistent with radiculopathy at the C5/6 IVF, i.e. C6 radiculopathy. During an extended observation period to rule out motor neuron disease, their weakness did not spread and the patients underwent posterior medial facetectomy and anterior foraminotomy. This produced marked improvement of the deltoid weakness soon after the operation. We considered unexpectedly wide motor innervation of the C6 nerve root predominantly in the deltoid, anatomic variations in the C5 root such as the trunk of the C5 root entering into the C5/6 IVF, and descending anastomoses connecting the C5 and C6 rootlets as possible explanations. Awareness of this rare presentation may aid in the diagnosis and surgical management of these patients.

Surgical outcome of posterior decompression for cervical spondylosis with unilateral upper extremity amyotrophy

STUDY DESIGN

Case studies of patients with cervical spondylosis with unilateral upper extremity amyotrophy.

OBJECTIVE

To clarify the surgical outcome of posterior decompression for this amyotrophy.

SUMMARY OF BACKGROUND DATA

Cervical spondylosis sometimes causes a characteristic severe muscular atrophy without sensory disturbance or lower-extremity dysfunction, which is the so-called "cervical spondylotic amyotrophy." However, response to treatment, especially to posterior decompression, has not been well understood.

METHOD

This study included 32 patients. All underwent posterior cervical laminoplasty, and 22 patients had an additional foraminotomy. Preoperative and postoperative muscle power and results of imaging and electrophysiologic studies were evaluated. The follow-up period averaged 78 months. Whether impingement was against the ventral nerve root (VNR) or anterior horn (AH) in the spinal cord was assessed according to these findings. These cases were divided into proximal type and distal type according to the most severely atrophic muscle and compared statistically.

RESULTS

Severe preoperative muscle atrophy was observed in the deltoid and biceps muscles of 24 patients (proximal type) and in the forearm and hand muscles of 8 patients (distal type). Impingements against the VNR and AH were observed in 21 and 28 cases, respectively, and 17 cases had impingement of both the VNR and AH. Improvements in muscle atrophy after surgery were observed in 25 cases. In proximal-type patients, muscle power improved in 92% of cases but was improved in only 38% of the distal-type cases.

CONCLUSIONS

Laminoplasty and foraminotomy were effective in the treatment of most patients with this syndrome, although the outcome in the distal type was inferior to that in the proximal type.

Microsurgical posterior foraminotomy with laminoplasty for cervical spondylotic radiculomyelopathy including cervical spondylotic amyotrophy

Object

The authors retrospectively investigated the surgical outcomes and radiographically documented changes after microsurgical posterior foraminotomy with en bloc laminoplasty in patients with cervical spondylotic radiculo-myelopathy (CSRM), including cervical spondylotic amyotrophy (CSA), during a period greater than 2 years.

Methods

Thirty-four consecutive patients (24 men and 10 women) were included in this study. Twenty patients had preoperative radicular pain, and CSA was diagnosed in 14 patients. The mean age at the time of surgery was 61 years (range 43–77 years). The follow-up period ranged from 2 to 6.5 years (mean 3.4 years). Foraminotomy was performed at 49 sites. Neurological improvement was evaluated using the Japanese Orthopaedic Association (JOA) scoring system; radicular pain and deltoid muscle strength were also evaluated clinically. Cervical lordosis, flexion–extension angles, range of motion (ROM), and the angulation and the extent of vertebral slippage at the affected nerve root levels were measured preoperatively and at last follow-up examination.

The mean rate of JOA score improvement was 67.2% (range 22.2–100%). In all 20 patients, preoperative radicular pain completely resolved after surgery. In all 14 patients with CSA, deltoid muscle strength improved; in approximately 80% of these patients, there was either no muscle weakness or only slight weakness. The flexion angles and ROM significantly decreased at the time of the last follow-up examination (p = 0.0402 and 0.0196, respectively). No other items changed significantly.

Conclusions

The aforementioned surgical procedure was safely completed and the surgical outcomes were satisfactory for CSRM including CSA. The instability (the angulation and the vertebral slippage) did not significantly change after surgery. This procedure yielded outstanding results and should be considered an option for cervical laminoplasty in the future.

Cervical Spondylotic Amyotrophy Treated by Anterior Decompression-Three Case Reports-

Cervical spondylotic amyotrophy (CSA) is a rare type of cervical spondylotic disorder. The surgical treatment of CSA is controversial. We treated three patients with the proximal type of CSA by anterior decompression. Three men (65, 61, and 58 years old) presented with CSA manifesting as unilateral muscle weakness and atrophy in the deltoid and biceps muscles without significant sensory deficit. Preoperative neuroradiological examinations revealed anterolateral spinal cord compression in one patient and ventral root compression in two patients at the C4-5 and C5-6 spaces. Magnetic resonance (MR) imaging showed no abnormal intramedullary signal intensity in any patient. Vertebrotomy deviated to the lesion side was performed to provide a better view of the laterally situated osteophytes. Anterior decompression was focused on the paramedial to lateral area, and further foraminotomy was performed according to the radiological findings. After decompression, intervertebral instrumentation was performed using titanium cervical cages. Two of the patients had good recovery of motor strength and one had moderate recovery despite persistent motor atrophy. Surgical intervention is effective in patients with CSA despite severe muscle atrophy unless MR imaging shows the presence of severe degenerative intramedullary lesion.

Acute arm paresis with cervical spondylosis: three case reports

BACKGROUND

The mild type of anterior spinal artery syndrome (ASAS) is characterized by motor loss with an absent or insignificant sensory deficit due to a disturbance in the blood supply to the anterior horn of the spinal cord. The clinical symptoms of cervical spondylotic amyotrophy (CSA) are motor loss or atrophy with an absent or insignificant sensory deficit or a long tract sign; however, the pathophysiology has not been clarified.

METHODS

Three patients who suffered from palsy of the deltoid and biceps brachii are presented. Magnetic resonance imaging confirmed the intrinsic cord disease as the cause of the paresis. We measured the central motor conduction time (CMCT) and the latencies of the tendon reflex (T waves) of the biceps and triceps and those of the F waves of the abductor pollicis brevis and abductor digiti minimi before, 2 weeks after, and 3 months after starting intravenous injections of prostaglandin E(1) (PGE(1)).

RESULTS

In these 3 cases, restoration of muscle strength began after starting injection of PGE(1). The electrophysiologic diagnosis revealed a disturbance of the motor conduction, in the CMCT and the latencies of the T waves, in the paretic muscle, which is more severe than that in other muscles. The radiological diagnosis suggested damage in the spinal cord. Improvements in the disturbance of the motor conduction and those of symptoms were parallel.

CONCLUSION

From symptomatologic or radiological viewpoints, it is difficult to differentiate CSA from ASAS with cervical spondylosis. This suggests that there have been patients with ASAS whom we have diagnosed as CSA, and we may add administration of PGE(1) to the treatment for the patients with CSA. The present 3 patients showed improvement of muscle strength after starting injections of PGE(1). Although this improvement was measured by an electrophysiologic method, the mechanisms of PGE(1) require further study.

Distal-type cervical spondylotic amyotrophy: assessment of pathophysiology from radiological findings on magnetic resonance imaging and epidurally recorded spinal cord responses

STUDY DESIGN

Six cases with distal-type cervical spondylotic amyotrophy are reported.

OBJECTIVE

To investigate the pathophysiology of distal-type cervical spondylotic amyotrophy from magnetic resonance imaging and intraoperative evoked spinal cord responses.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic amyotrophy had a characteristic clinical symptom of severe muscular atrophy with no or insignificant sensory deficit. Selective ventral root lesions or intrinsic spinal cord lesions have been proposed as the pathophysiology of cervical spondylotic amyotrophy, but they have not been well understood.

METHOD

Six patients with distal-type cervical spondylotic amyotrophy were described, and their magnetic resonance imaging and evoked spinal cord potentials after median nerve, motor cortex, and spinal cord stimulation were investigated.

RESULTS

Sagittal T2-weighted magnetic resonance imaging showed high signal intensity change within the spinal cord at C4-C5, C5-C6, and C6-C7. All patients underwent laminoplasty. The attenuation of postsynaptic potentials with preserved presynaptic potentials at C4-C5, C5-C6, and C6-C7 was characteristic in the evoked spinal cord potentials after median nerve stimulation. The amplitude of the evoked spinal cord potentials after median nerve stimulation was preserved at C2-C3. This means that lateral posterior column in the spinal cord had less or no involvement in distal-type cervical spondylotic amyotrophy. Concomitant hyperactivity of the patellar tendon reflex was correlated with the abnormality in the evoked spinal cord potentials after transcranial electric stimulation.

CONCLUSIONS

The results suggest a longitudinal gray matter lesion as one pathophysiologic feature, and that less damage to the lateral posterior column is the reason for the preservation of sensory function in the patients with distal-type cervical spondylotic amyotrophy described in this study.

Amyotrophic lateral sclerosis: frequent complications by cervical spondylosis

Cervical spondylosis is associated with myelopathy and radiculopathy, which sometimes mimic clinical manifestations of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder that affects upper and lower motor neurons. Cervical spondylosis may coexist with ALS because both diseases preferentially affect individuals of middle or old age. We investigated 63 patients with ALS to clarify the complications of cervical spondylosis and other spinal disorders and to explore the history of surgical treatment for them. We found cervical spondylosis in 30 patients (48%), lumbar spondylosis in 7 (13%), ossification of the posterior longitudinal ligament (OPLL) in 4 (6.3%), and ossification of the yellow ligament (OYL) in 4 (6.3%). Surgery was performed early in the course of the disease on the cervical spine in five patients (7.9%) and on the lumbar spine in one (1.6%); these patients consulted our clinic because their motor symptoms had progressed even after the spinal surgery. Our results indicate that nearly half of all ALS patients have their disease complicated by cervical spondylosis, and that a careful differential diagnosis for ALS is necessary before making decisions about spinal surgery.

Surgical management of dissociated motor loss following complex cervical spine reconstruction

STUDY DESIGN

A case of surgical management of dissociated motor loss after decompression of the cervical spine is reported.

OBJECTIVES

To present a rationale for surgical treatment of postdecompressive cervical radiculopathy with an illustrative case example.

SUMMARY OF BACKGROUND DATA

The unusual complication of radiculopathy after multilevel cervical decompressive procedures is characterized by pain or dissociated motor weakness of the C5 and C6 nerve roots. Conservative management paradigms, including analgesics and steroids, are the rule, but symptoms often persist for many months. There are currently no reports describing foraminotomy as a means of more rapidly alleviating the symptoms of radicular pain and deltoid and biceps brachii weakness seen in the postoperative setting.

METHODS

We present a case of bilateral C5 and C6 radiculopathy following multilevel cervical decompression for cervical spondylotic myelopathy, which we treated with posterior foraminotomies.

RESULTS

The patient reported complete resolution of his dermatomal pain and demonstrated rapid improvement in upper extremity strength as compared to traditional conservative treatments. The historical experience and pathogenesis regarding this postoperative complication are reviewed. The rationale of root-specific posterior decompression for this debilitating complication is discussed.

CONCLUSIONS

Foraminal decompression of the affected nerve roots as demonstrated here has not been described for postdecompressive dissociated motor loss. Such an approach may offer earlier and more complete relief to patients suffering from this unfortunate complication.

Clinical analysis of cervical radiculopathy causing deltoid paralysis

In general, deltoid paralysis develops in patients with cervical disc herniation (CDH) or cervical spondylotic radiculopathy (CSR) at the level of C4/5, resulting in compression of the C5 nerve root. Therefore, little attention has been paid to CDH or CSR at other levels as the possible cause of deltoid paralysis. In addition, the surgical outcomes for deltoid paralysis have not been fully described. Fourteen patients with single-level CDH or CSR, who had undergone anterior cervical decompression and fusion for deltoid paralysis, were included in this study. The severity of deltoid paralysis was classified into five grades according to manual motor power test, and the severity of radiculopathy was recorded on a visual analog scale (zero to ten points). The degree of improvement in both the severity of deltoid paralysis and radiculopathy following surgery was evaluated. Of 14 patients, one had C3/4 CDH, four had C4/5 CDH, three had C4/5 CSR, one had C5/6 CDH, and five had C5/6 CSR. Both deltoid paralysis and radiculopathy improved significantly with surgery (2.57+/-0.51 grades vs 4.14+/-0.66, P=0.001, and 7.64+/-1.65 points vs 3.21+/-0.58, P=0.001, respectively). In conclusion, the current study demonstrates that deltoid paralysis can develop due to CDH or CSR not only C4/5, but also at the levels of C3/4 and C5/6, and that surgical decompression significantly improves the degree of deltoid paralysis due to cervical radiculopathy.

Short term influence of mechanical factors on regional musculoskeletal pain: a study of new workers from 12 occupational groups

OBJECTIVES

To determine the influence of short term exposure to mechanical factors on regional musculoskeletal pain.

METHODS

Full time newly employed workers were recruited from 12 occupational groups and information collected by questionnaire. Subjects indicated on a blank body manikin any low back, shoulder, wrist or forearm or both, or knee pain which had occurred during the past month and had lasted more than 1 day. Data were also collected with a previously validated questionnaire on working postures, manual handling activities, and repetitive movements of the upper limb. The relations between mechanical factors and each area of pain were calculated as odds ratios (ORs) with 95% confidence intervals (95% CIs). Adjustment was made for age and sex.

RESULTS

1081 subjects (median age 23; interquartile range 20--27) were recruited to the study (a participation rate of 91%). 261 (24%) reported low back pain, 221 (20%) shoulder pain, 93 (9%) wrist or forearm pain, and 222 (21%) knee pain. Several specific manual handling activities were found to be associated with low back, shoulder, and knee pain. Carrying weights of more than 50 lbs (23 kg) on one shoulder was the factor which was most strongly associated with low back pain (OR 2.4 (95% CI 1.5 to 3.8)), shoulder pain (OR 3.1 (95% CI 1.9 to 4.8)), and knee pain (OR 3.5 (95% CI 2.2 to 5.5)), whereas forearm pain was most strongly associated with repetitive movements of the wrists (OR 1.8 (95% CI 1.04 to 3.1)). By contrast very few postures were associated with regional pain, although bending forwards in an uncomfortable position for at least 15 minutes was associated with shoulder pain (OR 1.6 (95% CI 1.2 to 2.2)) and kneeling for at least 15 minutes was associated with knee pain (OR 1.8 (95% CI 1.2 to 2.6)). Exposure to mechanical factors was most strongly associated with pain at multiple sites rather than with pains in individual regions.

CONCLUSIONS

Even among workers with only short term exposure to mechanical factors, musculoskeletal pain is increased.

Regression of cervical disc herniation observed on magnetic resonance images

STUDY DESIGN

A retrospective study of cervical disc herniation using results of repeated magnetic resonance imaging examinations.

OBJECTIVES

To clarify the cervical disc herniation morphological changes over time in order to establish a strategy for treatment.

SUMMARY OF BACKGROUND DATA

In the authors' previous magnetic resonance imaging follow-up study of patients with lumbar disc herniation, spontaneous regression was observed in the sequestration-type lesions, and it was found that the tendency toward regression differed based on the anatomic position of extruded disc material.

METHODS

Thirty-eight patients with cervical disc herniation who underwent repeated magnetic resonance imaging examinations were studied. The changes over time in herniated disc size were evaluated using this imaging technique. Evaluation showed the characteristics of those in whom spontaneous regression was found, such as extrusion pattern, and the clinical outcome was evaluated by symptoms.

RESULTS

In 15 patients (40%), the volume of herniated material was decreased. The interval from onset of symptoms to the initial examination was significantly shorter in the regression group than in the group that showed no change in disc herniation. By extrusion pattern, cervical disc herniation, which was divided into migration type on sagittal view and lateral type on axial view, most frequently exhibited spontaneous regression. All of the patients with radicular pain and upper limb amyotrophy were treated successfully with conservative therapy.

CONCLUSION

Although the possibility of the combination of hemorrhage and disc material could not be denied, active resorption of herniated material probably occurred during the acute phase. Extruded material exposed to the epidural space may be resorbed more quickly than that beneath the ligament. Vascular supply probably plays a role in the mechanism of resorption. The phase and position of extrusion were the significant factors affecting cervical disc herniation resorption. It was demonstrated that examination performed during the acute phase using magnetic resonance imaging is necessary for elucidation of the pathogenesis of cervical disc herniation, and that migrating, lateral-type herniations regress so frequently that conservative treatment should be chosen not only for patients with radicular pain, but also for those with upper limb amyotrophy.

Cervical spondylotic amyotrophy. Magnetic resonance imaging demonstration of intrinsic cord pathology

STUDY DESIGN

Three case reports.

OBJECTIVE

To elucidate the pathophysiology of cervical spondylotic amyotrophy.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic amyotrophy is the clinical syndrome in cervical spondylosis characterized by severe muscular atrophy in the upper extremities, with an absent or insignificant sensory deficit. Pathophysiology of this particular syndrome has not been well understood.

METHODS

Three cases of cervical spondylotic amyotrophy are presented in which magnetic resonance imaging confirmed the intrinsic cord disease as the cause of the syndrome.

RESULTS

The patients had segmental muscular atrophy of the proximal upper extremities, with an absent or insignificant sensory deficit. After initial disease progression, the symptoms stabilized for years. Sagittal T2-weighted magnetic resonance images showed multi-segmental linear high-signal intensity within the compressed spinal cord. These high-signal intensity lesions appeared to be located at the anterior horns on axial images. The spinal cord compression was less severe in the neck-neutral position, but spinal canal stenosis increased when the neck was extended.

CONCLUSIONS

The results suggest that one pathophysiology of this syndrome may be multisegmental damage to the anterior horns caused by dynamic cord compression, possibly through circulatory insufficiency.