Incidence of Motor Neuron Disease (MND) in Patients Diagnosed with Cervical Spondylotic Myelopathy (CSM)

Abstract

Objective: Motor neuron disease (MND) can occur in patients with cervical spondylotic myelopathy. The purpose of this study was to determine the prevalence of motor neuron disease in individuals suffering from cervical spondylotic myelopathy (CSM). Materials & Methods: A prospective study was conducted at the Lady Reading Hospital. The patients(n = 70) included were between ages 55 to 75 with established clinical and radiological diagnoses of CSM. Motor neuron disease was diagnosed clinically by Awaji criteria. The patients were evaluated with NCS/EMG (Nerve Conduction Studies/Electromyography) and followed for 6 months. The motor neuron disease was confirmed by modified El Escorial criteria. Results: 40 patients had bilateral upper limb weakness (57%), however, the rest of the 30 patients had unilateral upper extremity weakness (42.8%). Hoffman’s sign was positive in 60% of patients. Lhermitte's sign was also positive in 31% of patients. The majority of patients (55.7%) were found with grade 4 for deltoid followed by 51.4% patients for biceps brachii. MRI showed anterior cord compression at the level of C5 and C6 in 27.14% of patients and C6 C7 in 32.8% of patients. 15.7% of patients were suspected of having both CSM and MND. Conclusion: CSM and MND can occur in the same patients. The incidence of MND is 5.7% in patients with cervical spondylotic myelopathy, hence in CSM patients, workup must be done for MND as it affects the outcome of surgery in these patients.