Motor evoked potential is useful for monitoring the effect of collar therapy in cervical spondylotic myelopathy

The value of Clinical signs in the diagnosis of Degenerative Cervical Myelopathy - A Systematic review and Meta-analysis

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is likely due to a combination of its subtle symptoms, incomplete neurological assessments by clinicians and a lack of public and professional awareness. Diagnostic criteria for DCM will likely facilitate earlier referral for definitive management.

OBJECTIVES

This systematic review aims to determine (i) the diagnostic accuracy of various clinical signs and (ii) the association between clinical signs and disease severity in DCM?

METHODS

A search was performed to identify studies on adult patients that evaluated the diagnostic accuracy of a clinical sign used for diagnosing DCM. Studies were also included if they assessed the association between the presence of a clinical sign and disease severity. The QUADAS-2 tool was used to evaluate the risk of bias of individual studies.

RESULTS

This review identified eleven studies that used a control group to evaluate the diagnostic accuracy of various signs. An additional 61 articles reported on the frequency of clinical signs in a cohort of DCM patients. The most sensitive clinical tests for diagnosing DCM were the Tromner and hyperreflexia, whereas the most specific tests were the Babinski, Tromner, clonus and inverted supinator sign. Five studies evaluated the association between the presence of various clinical signs and disease severity. There was no definite association between Hoffmann sign, Babinski sign or hyperreflexia and disease severity.

CONCLUSION

The presence of clinical signs suggesting spinal cord compression should encourage health care professionals to pursue further investigation, such as neuroimaging to either confirm or refute a diagnosis of DCM.

Application of electrophysiological measures in degenerative cervical myelopathy

Degenerative cervical myelopathy (DCM) is one of the leading causes of progressive spinal cord dysfunction in the elderly. Early diagnosis and treatment of DCM are essential to avoid permanent disability. The pathophysiology of DCM includes chronic ischemia, destruction of the blood–spinal cord barrier, demyelination, and neuronal apoptosis. Electrophysiological studies including electromyography (EMG), nerve conduction study (NCS), motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) are useful in detecting the presymptomatic pathological changes of the spinal cord, and thus supplementing the early clinical and radiographic examinations in the management of DCM. Preoperatively, they are helpful in detecting DCM and ruling out other diseases, assessing the spinal cord compression level and severity, predicting short- and long-term prognosis, and thus deciding the treatment methods. Intra- and postoperatively, they are also useful in monitoring neurological function change during surgeries and disease progression during follow-up rehabilitation. Here, we reviewed articles from 1979 to 2021, and tried to provide a comprehensive, evidence-based review of electrophysiological examinations in DCM. With this review, we aim to equip spinal surgeons with the basic knowledge to diagnosis and treat DCM using ancillary electrophysiological tests.

The prediction of intraoperative cervical cord function changes by different motor evoked potentials phenotypes in cervical myelopathy patients

Background

Surgery is usually the treatment of choice for patients with cervical compressive myelopathy (CCM). Motor evoked potential (MEP) has proved to be helpful tool in evaluating intraoperative cervical spinal cord function change of those patients. This study aims to describe and evaluate different MEP baseline phenotypes for predicting MEP changes during CCM surgery.

Methods

A total of 105 consecutive CCM patients underwent posterior cervical spine decompression were prospectively collected between December 2012 and November 2016. All intraoperative MEP baselines recorded before spinal cord decompression were classified into 5 types (I to V) that were carefully designed according to the different MEP parameters. The postoperative neurologic status of each patient was assessed immediately after surgery.

Results

The mean intraoperative MEP changes range were 10.2% ± 5.8, 14.7% ± 9.2, 54.8% ± 31.9, 74.1% ± 24.3, and 110% ± 40 in Type I, II, III, IV, and V, respectively. There was a significant correlation of the intraoperative MEP change rate with different MEP baseline phenotypes (r = 0.84, P < 0.01). Postoperative transient new spinal deficits were found 0/31 case in Type I, 0/21 in Type II, 1/14 in Type III, 2/24 in Type IV, and 4/15 in Type V. No permanent neurological injury was found in our cases series.

Conclusions

The MEP baselines categories for predicting intraoperative cervical cord function change is proposed through this work. The more serious the MEP baseline abnormality, the higher the probability of intraoperative MEP changes, which is beneficial to early warning for the cervical cord injury.

Medical management of Pott disease in the thoracic and lumbar spine: a prospective clinical study

OBJECT

The aim of this study was to evaluate conservative medical management of 44 patients with Pott disease. The prognostic significance of various clinical, radiological, and long-term follow-up findings in these patients was also evaluated.

METHODS

Between January 1990 and January 2005 data were collected prospectively at the authors' clinic in 44 patients with Pott disease in the thoracic or lumbar spine. These patients had no major neurological deficits or severe spinal deformities. The study population consisted of 21 male (48%) and 23 female (52%) patients, with a mean age of 42.1 years (range 10-70 years). The most common region of Pott disease was the thoracolumbar junction (18 cases; 41%), followed by the thoracic (16 cases; 36%) and lumbar (10 cases; 23%) regions. All patients presented with abscesses. With the exception of two cases, all had kyphotic angles smaller than 30 degrees. At presentation, 20 patients had neurological signs of spinal cord compression during clinical examination. Both clinical and biopsy findings were used in all cases for diagnosis. A diagnosis was confirmed by a positive biopsy specimen culture in 19 (43.2%) of 44 cases, and histopathological findings were compatible with the results of these cultures in all cases. All patients were treated with antituberculous chemotherapy, and the diseases in only two (4.5%) was resistant to the regimen. An independent observer assessed the clinical and imaging findings after a mean follow-up duration of 40 months. Forty-two (95.4%) of the 44 patients were successfully treated with conservative medical management and attained acceptable spinal deformity angles, and none of these patients had any residual instability, radiculopathy, or neurological compromise. Only 4.5% of the patients experienced residual spine deformity (as much as a 30 degrees kyphotic angle), which was clinically obvious but biomechanically stable.

CONCLUSIONS

Patients with Pott disease in the lumbar or thoracic region, without neurological deficits or kyphosis, can be treated conservatively in the vast majority of cases. Indications for surgery need to be redefined given these new data.

The role of sensory and motor evoked potentials in the prognosis of Pott's paraplegia

OBJECTIVE

In view of paucity of evoked potential changes in Pott's paraplegia, it is proposed to evaluate the role of motor and somatosensory evoked potentials in predicting the outcome.

METHODS

Consecutive patients with Pott's paraplegia during 1993-2003 were subjected to detailed clinical, radiological and evoked potential study. The latter comprised of tibial somatosensory evoked potential (SEP) and motor evoked potential (MEP) study to tibialis anterior. The patients were clinically evaluated at 6 and 12 months and the outcome was defined into poor (bed ridden), partial (dependent for activities of daily living) and complete recovery (independent). The evoked potential findings were correlated with clinical and radiological findings and outcome.

RESULTS

There were 39 patients whose age ranged between 16 and 70 (mean 42.1) years and 22 were females. The mean duration of symptoms was 8.2 months. Sensory motor deficit was present in 18 and pure motor signs in 21 patients. Five patients had quadriplegia and remaining had paraplegia. The muscle weakness was severe in 12 and moderate in 15 patients. In 12 patients, lower limb power was normal but they had lower limb hyper-reflexia with or without spasticity suggesting pyramidal dysfunction. Pinprick and joint position sensations were abnormal in 18 patients. MRI was abnormal in all and revealed cervical involvement in 7, thoracic in 22 and lumbar in 10 patients. Paravertebral soft tissue shadow was present in 36 and cord compression in 30 patients. Motor evoked potential was abnormal in 19 patients (unrecordable in 11 patients, 21 sides and prolonged in 8 patients, 14 sides). SEP was abnormal in 18 patients (unrecordable in 15 patients, 25 sides and prolonged central conduction in 8 patients, 9 sides). Both MEP and SEP were abnormal in 16, normal in 18, and only MEP was abnormal in 3 and only SEP in 2 patients. At 6 month 25 patients had complete, 9 partial and 5 poor recovery. At 1 year 33 had complete and 4 partial recovery. SEP and MEP abnormalities correlated with respective sensory and motor functions, vertebral level and outcome at 6 and 12 months.

CONCLUSIONS

MEP and SEP both are helpful in predicting 6-month outcome. Combining SEP and MEP gives stronger correlation with 6-month outcome compared to only MEP or SEP. The potential role of evoked potentials in deciding different therapeutic strategies needs further studies.

Systematic correlation of transcranial magnetic stimulation and magnetic resonance imaging in cervical spondylotic myelopathy

STUDY DESIGN

A prospective study over a 3.5-year period involving transcranial magnetic stimulation and magnetic resonance imaging.

OBJECTIVES

To assess the correlation of transcranial magnetic stimulation and magnetic resonance imaging in cervical spondylotic myelopathy qualitatively and statistically.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic myelopathy presents with different degrees of cord compression, which can be assessed by magnetic resonance imaging. There are no large studies correlating transcranial magnetic stimulation and magnetic resonance imaging findings in this condition.

METHODS

A total of 141 patients with a clinical diagnosis of cervical spondylotic myelopathy were prospectively studied over a 3.5-year period. They were classified into Groups 1 to 4 based on severity of cervical cord changes on magnetic resonance imaging. All had transcranial magnetic stimulation and central motor conduction time measurements within 2 months of the magnetic resonance imaging study.

RESULTS

Twenty-eight, 49, 28, and 36 patients were classified into Groups 1 to 4, respectively. Mean upper limb and lower limb central motor conduction times correlated with the severity of magnetic resonance cord compression. The absence of central motor conduction time abnormalities correlated reliably with the absence of cervical cord impingement as in Group 1. Statistically significant right left difference in central motor conduction time in the lower limbs was seen between Groups 1 (no cord changes) and Group 2 (mild cord impingement). Eight other patients with diagnoses other than cervical spondylotic myelopathy all showed central motor conduction time abnormalities. The sensitivity and specificity for transcranial magnetic stimulation for differentiating the presence from absence of magnetic resonance imaging cord abnormality were 100% and 84.8%, respectively.

CONCLUSIONS

Transcranial magnetic stimulation showed excellent correlation with magnetic resonance imaging findings and can be considered as an effective technique for screening patients for cervical cord abnormalities before magnetic resonance imaging in the clinical setting. The findings in this study have relevant implications in the pathophysiology, management, and health costs of cervical spondylotic myelopathy.

Electrophysiologic assessment of shoulder girdle weakness in patients with cervical spondylosis: prognostic value of supraclavicular stimulation

OBJECTIVES

We tested the use of supraclavicular stimulation as a prognostic measure of deltoid function after cervical spondylotic radiculopathy.

METHODS

Electrophysiological study consisted of supramaximally stimulating the brachial plexus and recording compound muscle action potentials (CMAPs) from the deltoid in 32 patients with unilateral weakness of 3 months or shorter duration as compared with 69 healthy subjects.

RESULTS

Despite considerable individual variability and age-related reduction in amplitude and area of deltoid CMAPs, the side-to-side ratios yielded useful, reproducible values. The measures recorded initially correlated significantly with the eventual recovery of deltoid strength but, interestingly, not with the initial degree of weakness. In particular, the CMAPs greater than 50%, even in the face of severe weakness, predicted a nearly complete return of function.

CONCLUSIONS

Supraclavicular stimulation provides a useful measure in monitoring deltoid weakness and predicting its recovery in patients with cervical spondylosis.

Is methyl prednisolone useful in acute transverse myelitis?

STUDY DESIGN

Hospital based observational study.

OBJECTIVES

To evaluate the role of methyl prednisolone (MPS) in the management of acute transverse myelitis (ATM).

METHODS

Twenty-one patients with ATM were included in a prospective hospital based study during 1992-1997. All the patients underwent neurological examination, spinal MRI, somatosensory and motor evoked potentials of both upper and lower limbs and concentric needle EMG study. Twelve consecutive patients did not receive MPS therapy who were managed during 1992-1994 and nine consecutive patients during 1995-1997 received MPS therapy in a dose of 500 mg i.v. for 5 days. The clinical and neurophysiological studies were repeated 3 months later. The outcome was defined on the basis of Barthel index (BI) score at the end of 3 months into good (BI> or =12) and poor (BI<12).

RESULTS

The age of MPS group was 25.5 years (range 12-42) and three were females. The age of non MPS group was 33.5 years (range 16-70) and two were females. In the MPS group 33% had poor outcome compared to 67% in the non MPS group. In the MPS group mean admission BI score was 7.3 which improved to 14.6 after MPS therapy. In the non MPS group, the admission BI score was 3.2 which improved to 9.6 at 3 month follow-up. In patients with complete paraplegia, evidence of denervation on EMG and unrecordable central motor conduction time to lower limb and tibial SEP were associated with poor outcome irrespective of MPS treatment. Global test statistics did not suggest a beneficial role of MPS therapy in the outcome of ATM.

CONCLUSION

Our results do not suggest a beneficial role of methyl prednisolone on the 3 month outcome of ATM.

Motor and somatosensory evoked potentials in tuberculous meningitis: a clinico-radiological correlation

OBJECTIVE

The sensory and motor functions in severe tuberculous meningitis (TBM) may be difficult to assess clinically and may be helped by evoked potential studies. Lack of motor and somatosensory evoked potential studies in TBM prompted the present study.

METHODS

All the patients with TBM underwent detailed neurological evaluation and cranial CT scan study. Motor and somatosensory evoked potentials to both upper and lower limbs were carried out bilaterally. The outcome was defined on the basis of 3 month Barthel Index (BI) score into good (BI > 12) and poor (BI < 12).

RESULTS

Forty-one highly probable patients with TBM whose ages ranged between 8 and 64 years and 14 of whom were females were included in this study. Twenty-three patients were in stage III (meningitis, neurological signs and altered sensorium), 12 in stage II (meningitis with neurological sign) and the remaining patients were in stage I (meningitis only). Cranial CT scan was carried out in all and MRI in 18 patients. On CT scan hydrocephalus was present in 21, infarction in 14 and tuberculoma in 4 patients. Motor evoked potential (MEP) was abnormal in 18 patients (36 limbs) and SEP in 9 patients (23 limbs). Upper limb central motor conduction time to abductor digiti minimi (CMCT-ADM) was abnormal in 15 and that to tibialis anterior (TA) in 21 limbs. CMCT abnormality was lateralized in 6 and only upper or lower limbs were involved in 11 patients. The SEP abnormalities were lateralized in 2 patients and only upper or lower limbs were involved in 3. The MEP changes correlated with stage of TBM and outcome whereas SEP with outcome only.

CONCLUSION

Motor and somatosensory evoked potentials may be helpful in objective documentation of respective motor and sensory functions in TBM patients with altered sensorium.