Neck and cervical spine

12 Neck and cervical spine


The commonest orthopaedic cause of neck disorders is degeneration of a cervical intervertebral disc. This may lead to protrusion of part of the disc contents (prolapsed cervical disc) or, more often, it may give rise to secondary osteoarthritic changes in the intervertebral joints (cervical spondylosis). These conditions together make up a large proportion of the disabilities of the neck encountered in an orthopaedic out-patient department. Another major cause of prolonged pain and stiffness of the neck is the common post-traumatic musculo-ligamentous strain known generally as whiplash injury.


A disorder of the cervical spine often interferes with the roots of the brachial plexus, causing radiating pain, muscle weakness, or sensory impairment in the corresponding upper limb. Indeed, the clinical importance of a cervical disorder often lies in its neurological effects rather than in the local lesion itself.



SPECIAL POINTS IN THE INVESTIGATION OF NECK COMPLAINTS








NEUROLOGICAL EXAMINATION OF UPPER LIMBS


This is an essential step in the investigation of the neck because cervical lesions so often interfere with the brachial plexus.


Muscular system. The muscles of the shoulder girdle, arm, forearm, and hand must be examined for wasting or fasciculation, a comparison being made on the two sides. The tone and power of each muscle group are then tested in turn and a comparison is made with the opposite limb. It is worth remembering the major root innervation for each muscle group when testing; C5 to deltoid, C6 biceps and wrist extensors, C7 triceps and wrist flexors, C8 finger flexors, and T1 to intrinsic muscles of hand.


Sensory system. Examine the patient’s sensibility to touch and pin prick. In appropriate cases test also the sensibility to deep stimuli, joint position, vibration, and heat and cold. The nerve roots supplying the sensory dermatomes in the upper limb are shown in Fig. 12.2. In the assessment of sensory loss it should be remembered that the middle or long finger, representing the central axis of the limb, is innervated mainly from the seventh cervical nerve. The radial half of the hand is innervated by the proximal roots of the brachial plexus (C5, C6) whereas the ulnar half is innervated from the more distal roots (C8, T1).



Sweating. Feel whether the digits are moist or dry. Sweating is dependent upon intact sudomotor nerve fibres.


Reflexes. Compare on the two sides the biceps jerk (mainly C6), the triceps jerk (mainly C7), and the brachioradialis jerk (mainly C6).


From the findings elicited it should be possible to determine whether there is a neurological disturbance and, if so, whether it is of upper or lower motor neurone type, and the identity of the roots, trunks, or branches involved.






DEFORMITIES AND CERVICAL INSTABILITIES



INFANTILE TORTICOLLIS (‘Congenital’ torticollis; muscular torticollis)


In infantile torticollis (wry neck) the head is tilted and rotated by contracture of the sternomastoid muscle of one side. Strictly this is not a true congenital deformity because it arises after birth. With improvements in obstetrical practice it is now seen much less often than it was in the past.


Cause. This is uncertain. Probably there is interference with the blood supply of the sternomastoid muscle, caused by injury during birth.


Pathology. In the established condition, part of the affected muscle is replaced by contracted fibrous tissue. In some cases contracture is known to have been preceded, in early infancy, by a tumour-like thickening of the muscle (‘sternomastoid tumour’), the histology being that of muscle infarction and replacement by fibrous tissue.


Clinical features. The child, often between 6 months and 3 years old when brought for consultation, is noticed to hold the head on one side. On examination, the contracted sternomastoid muscle is felt as a tight cord. The ear on the affected side is approximated to the corresponding shoulder. In long-established cases there is retarded development of the face on the affected side, with consequent asymmetry (Fig. 12.3).



Diagnosis. The condition has to be distinguished from other forms of wry neck, including structural deformities of the cervical spine, ocular torticollis, muscle spasm from a local inflammatory lesion such as infected glands, and psychogenic (hysterical) torticollis. The important diagnostic features are the history, the cord-like contracted sternomastoid muscle, and the facial asymmetry. Imaging of the spine with plain radiographs is important to exclude any underlying vertebral abnormalities or subluxations.


Treatment. If the condition is seen at the stage of ‘sternomastoid tumour’, repeated stretching of the muscle under the supervision of a physiotherapist is effective. In established cases the contracted muscle should be divided at its lower attachment. After operation corrective exercises should be encouraged.





CERVICAL SUBLUXATION AND DISLOCATION (Spontaneous subluxation of the cervical spine; cervical spondylolisthesis)


Most displacements of the cervical spine are caused by injury, but in some circumstances there may be spontaneous displacement, usually forwards, of a cervical vertebra upon the one next below it.


Causes and pathology. There are three types, caused by:





Congenital or acquired non-fusion of dens. Occasionally the dens fails to fuse with the body of the axis by bone, being attached only by fibrous tissue (os odontoideum). Under the constant stress of superimposed weight the fibrous bond slowly stretches, allowing the dens, and with it the atlas and skull, to slide gradually forwards upon the axis (Fig. 12.4A). A similar condition may exist after fracture of the dens, but this would be preceded by a history of trauma. Instability may also be present in patients with Down’s syndrome and radiological screening may be indicated in patients with this condition.



Inflammatory softening of the transverse ligament of the atlas. In this type the underlying cause is an inflammatory lesion in the upper part of the neck, such as rheumatoid arthritis or a severe local infection of the throat or glands. There is rarefaction of the atlas, with softening of the transverse ligament. In consequence the atlas is able to slide forwards upon the axis (Fig. 12.4B).


Instability from previous injury or from arthritis. A traumatic fracture- dislocation or subluxation at any level in the cervical spine may cause permanent instability, with a liability to slow redisplacement months or years after the initial injury (Fig. 12.4C).


In all types the upper segment is displaced forwards in relation to the lower. The spinal canal becomes progressively more flexed and narrowed, and there is always a grave risk of compression of the spinal cord.


Clinical features. In the inflammatory type there is complaint of ‘stiff neck’. The head is held rigidly, the cervical muscles being in spasm. In subluxation from congenital or post-traumatic instability there are discomfort and stiffness in the neck, and flexion deformity is apparent. Radiographs will show the displacement, its level and its type (Fig. 12.5).



Complications. In all types the complication to be feared is compression of the spinal cord. The first symptoms appear in the upper limbs and consist of root pain, paraesthesiae, motor weakness, or sensory impairment. Eventually, increasing cord compression may lead to spastic paralysis below the level of the lesion, and to bladder and bowel dysfunction.


Treatment. This depends upon the underlying cause and upon whether or not neurological disturbance is present.


Inflammatory type. The displacement is reduced by head traction, which is continued for two weeks. Thereafter the neck is immobilised in extension in a plaster jacket for 2 months. Atlanto-axial fusion may be required.


Congenital or post-traumatic instability

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Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on Neck and cervical spine

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