Clinical Tests and Differential Diagnosis of Cervical 05 Spondylotic Myelopathy Jesus Lafuente Introduction MRI, and clinical symptoms is essential for a correct diagnosis. Anterior-posterior width Cervical spondylotic myelopathy (CSM) is reduction, cross-sectional evidence of cord a disabling disease caused by a combina- compression, obliteration of the subarach- tion of mechanical compression and vascu- noid space, and signal intensity changes to lar compromise of the spinal cord. It is the the cord found on MR imaging are consid- most common cause of spinal dysfunction ered the most appropriate parameters for in older patients.1 The onset is often insidi- confirmation of a spinal cord compression ous with long periods of episodic, stepwise myelopathy.4 In some occasions when the progression and may present with different diagnosis is still not clear, the use of other symptoms from one patient to another.2 CSM studies could help, such as diagnostic elec- is a clinical diagnosis that may involve broad- trophysiology and cerebrospinal fluid (CSF) based gait disturbances first, associated with examination. weakness of the legs, and then spasticity.3 As spinal cord degeneration progresses, lower motor neuron findings in the upper extremi- Clinical Tests ties, such as loss of strength, atrophy, and CSM is the most common cause of spinal difficulty in fine finger movements, may cord dysfunction in the world. A meticu- present.3 Additional clinical findings may lous physical examination of patients with include: neck stiffness, shoulder pain, pares- cervical pathology can relatively make the thesia in one or both arms or hands, radicu- distinction between radiculopathy or mye- lopathy, a positive Hoffman and/or Babinski lopathy easy. Routine physical examination sign, motor deficits, hyperreflexia, and bowel of patients with cervical myelopathy should and bladder dysfunction.3 include special tests in addition to a thor- Physical examination findings are not ough neurological examination. The relevant always consistent with severity of disease in clinical examination tests are categorized in CSM; therefore, correlation to plain X-rays, Table 5.1. Table 5.1 Clinical examination tests used for cervical spondylotic myelopathy Upper motor Provocative Motor deficit Sensory deficit Gait and balance neuron deficit test Muscle Proprioception Hoffman´s reflex L´hermitte sign Romberg test weakness Vibratory test Babinski reflex Heel and toe walk Finger scape test Pinprick Sustained clonus Grip and release Inverted radial reflex Scapulohumeral test Hyperreflexia Clinical Tests and Differential Diagnosis of Cervical Spondylotic Myelopathy 39 Muscle Weakness the radial innervated extensor muscles (digiti minimi, digitorum communis).6 The causes of lack of muscle strength are From the physiological standpoint, this many; however, in CSM, the most common sign is easily understandable. Adduction of cause is due to a peripheral muscular fatigue, the little finger is performed by the inter- which represents the inability of a specific osseous and abduction by the hypothenar muscle to work, secondary to a loss or dys- muscles. Both groups of the muscles are function on any of the motor neurological innervated by the ulnar nerve. However, pathways. This can be caused by osteophytes in abduction of the little finger, the exten- or prolapsed discs that compress either the sor digiti minimi and the branch to the little spinal cord directly or the spinal nerves. It finger of extensor digitorum communis also is important to distinguish weakness from play a definite part; both are innervated by fatigue or asthenia, which are separate condi- radial nerve. If the muscles innervated by the tions with different etiologies that can coexist ulnar nerve are weak, those innervated by the with, or be confused for, weakness. intact radial nerve predominate in strength and abduct the little finger. Thus, it is under- Technique standable why this abduction of the little The patient stays in a sitting position and the finger is best seen when extensor digitorum doctor tests the level of strength in all muscle communis comes into action and extends the groups, examining from upper to lower extre- fingers and the hand. In cases with combined mities and quantifying the severity of muscle palsy of ulnar nerve and radial nerve, this weakness, according to the Medical Research sign would not be present. 5 Council (MRC) criteria : The finger scape sign is not only seen in • Grade 0: No contraction or muscle ulnar nerve palsies but also in patients with movement. syringomyelia and is an important examina- • Grade 1: Trace of contraction but no tion test in the myelopathic hand together movement at the joint. with grip and release. • Grade 2: Movement at the joint with gravity eliminated. Technique • Grade 3: Movement against gravity but The patient is placed with the wrist in a neu- not against added resistance. tral position, and forearm fully pronated and • Grade 4: Movement against exter- instructed to perform full extension of all nal resistance with less strength than the fingers. Once digits are extended, patient usual. is asked to fully abduct all fingers and then • Grade 5: Normal strength. adduct all fingers. A positive sign is indicated This grading is not only an excellent tool to with the observation of abduction, along with determine muscle weakness but also a great the inability to adduct the 5th digit when tool to evaluate progression and recovery extended (Fig. 5.1). after treatment. Grip and Release Test The Wartenberg´s Sign or Finger Scape Sign Grip and release test is used to evaluate hand function in myelopathic patients. Grip and It was first described by Robert Wartenberg release tests are part of a group of quantita- in 1939. Wartenberg’s sign refers to the tive clinical tests together with 10-step test slightly greater abduction of the fifth digit, and the 30 meters walking test.7 They are due to paralysis of the abducting palmar all common, in that they can demonstrate interosseous muscle and unopposed action of an improvement numerically, comparing 40 Chapter 05 Fig. 5.1 Wartenberg scape test. 5th finger on abduction and flexion as the lesion does not allow the finger to adduct (radial nerve dominance). a b Fig. 5.2 Grip and release quantitative test. Opening and closing the hand. Normal value: > 20 in 10 seconds. the performance before and after rehabilita- Proprioception tion or surgery. This improvement normally Proprioception, or kinesthesia, is the sense coincides with better results in other clinical that lets us perceive the location, move- assessment subjective scales such as Japanese ment, and action of parts of the body. When Orthopaedic Association (JOA), short form- we move, our brain senses the effort, force, 36 (SF-36), neck disability index (NDI), and and heaviness of our actions and positions quality-adjusted life-years (QALY) and is and responds accordingly, for example, pro- reflection of a good management outcome. prioception enables a person to close their It is believed that changes in grip aperture eyes and touch their nose with their index control are caused mainly by pyramidal tract finger. Proprioception includes a complex damage in the spinal cord; however, recent of sensations, including perception of joint studies confirm the importance of soma- position and movement, muscle force, and tosensory inputs from the hand into grip effort. In proprioception, the neuromuscu- 8 aperture control. lar control is the efferent motor response to afferent (sensory) information, and it is a Technique constant feedback loop that tells your brain In this reflex, the patient is asked to form a fist what position you are in and what forces are and then extend the fingers, rapidly repeat- acting upon your body at any given point in ing the sequence. A normal response is more time.9 Proprioception relies on the relation- than 20 times in a 10-second period. Patients ship between the body’s central nervous with cervical myelopathy (myelopathic hand) system (CNS) and certain soft tissues, includ- cannot achieve this goal (Fig. 5.2). ing muscles, tendons, and ligaments. Sensory Clinical Tests and Differential Diagnosis of Cervical Spondylotic Myelopathy 41 receptors in the muscles are called muscle Vibratory Sensation spindles, which are long proteins encapsu- lated in sheaths that lay parallel to muscle Assessment of vibration sense is the best fibers. These muscle spindles are stretched clinical test of the dorsal column pathway. on muscle extension and is the degree of this Vibration sense is tested with a tuning fork stretch effort that is delivered through the (normally 128 Hz) placed on predefined bony spinal nerves to the nervous system, which prominences (with the eyes closed), and the facilitates a signal sent to the muscle to con- patient is asked to report when the vibration tract or relax. starts and stops. Sensory receptors (mostly Proprioception sensory output ascends Pacinian and Meissner corpuscles) convert through the dorsal columns in the spinal cord. the vibration into a neural signal. The tem- Normal proprioception lets you move freely poral resolution of the neural information without giving your movements a second transfer (action potentials) should be at least thought. Abnormal proprioception causes equal to the frequency of the vibration. With symptoms that can interfere with even the age, the vibratory response might be lost in simplest activities and even can cause you the ankle and both feet. Vibratory sensation 10 to fall in severe cases. In upper extremity is often diminished in peripheral neuropathy injuries like in CSM, you may have difficulty and myelopathy but spared in disease con- reaching properly, and you may have prob- fined to the cerebral cortex, orientating the lems with fine motor tasks that require preci- problem to a spinal one. sion of movement (myelopathic hand). This is caused by a loss in proprioception. Technique The patient is asked to lay on the couch. Technique The examiner explains the procedure The patient is positioned lying on the bed.