The spine is an anatomical marvel designed to play a vital role in our well being. Any injury to our spine threatens our mobility and productivity.

The cervical spine has three main functions – to carry and buttress the head; to allow motions of the head in all directions and to protect the supply and communication lines between head and body. ‘Form follows function’ is a principle in evolution – and so the construction of the cervical spine is well adapted to fulfill these functions. Seven solid cervical vertebrae connected by intervertebral discs are joined by a complex network of ligaments and muscles, like masts and rigging of a sailing vessel.

Understanding the spine

The first two cervical vertebrae iffer considerably from the other five: they have to allow the main rotation and flexion-extension of the head. Their names are well-chosen: ‘Atlas’ – according to Greek mythology, Zeus condemned the Titan Atlas to stand at the western edge of the earth and to hold up the sky on his shoulders. By analogy the first vertebra has to shoulder the head. ‘Axis’ – the second cervical vertebra forms the pivot (axis) upon which the Atlas rotates. Depending on mechanism, impact of injury, compression, flexion, extension, rotation, translation and their combinations act as main-injury-vectors and these are also used for classification, decision-making, and in planning for surgery.

Injuries and complications

Motor vehicle accidents account for 50% of cervical spine injuries, falls, for another 20%. Sports-related activities are responsible for 15%, the remaining are attributed to interpersonal violence. The following athletic activities must be considered high risk for cervical spine lesions: Diving, horse riding, football, gymnastics, skiing, and hang-gliding. The most feared complications of unstable cervical spine injuries are spinal cord or nerve root lesions. About 40% of cervical fractures have some degree of associated neurologic deficit. The risk of neurologic impairment secondary to spinal lesions increases considerably with preexisting degenerative changes of the spine.

Cervical spine injuries cause an estimated 6,000 deaths and 5,000 new cases of quadriplegia each year in the USA. Death due to high cervical spine injuries usually occurs immediately from stretching of the brainstem causing respiratory arrest.

Burst and wedge compression fractures:

Axial compression can burst the bodies of the third to seventh cervical vertebrae, or under an additional flexion vector, produce a wedge compression fracture. Both can be accompanied by a variable degree of encroachment of the spinal canal with bone.

Subluxation with unilateral or bilateral facet dislocation:

Injuries associated with flexion-rotation mechanisms lead to disruptions of the posterior ligaments with unilateral or bilateral facet dislocations.

“Whiplash” injury:

When the head snaps forward and then back again by a rear-end collision of motor vehicles it leads to a sudden distorting of the neck with impulsive stretching of the spine, mainly the ligaments. Heavy and long-lasting symptoms may occur: Pain and aching to the neck, sensory disturbances (“pins and needles to the arm”), and headaches.

Getting the diagnosis right

Exploration of history and injury-mechanism combined with a careful clinical examination must be followed by imaging studies:Radiography with a standard trauma series composed of 5 views: cross-table lateral, swimmer’s, oblique, odontoid, and anteroposterior views. Multidetector Computed Tomography (CT Scan) is considered today as a primary diagnostic test. The American College of Orthopedic Surgeons now recommends routine cervical spine screening via CT scan instead of plain radiography. Disco-ligamentous injuries have traditionally been evaluated by stress views under flexion and extension. MRI is less dangerous and more sensitive for soft tissue lesions than radiography.

Recommended treatment

Today there are very few indications for conservative treatment protocols including closed reduction by skeletal traction with tongs and orthosis, Halo-vest, or Minerva plaster cast immobilization. Operative fracture fixation after closed or open reduction of dislocations or deformities is considered as state-of-art. A real osteosynthesis however is only the screw fixation of odontoid fractures. The other fixation techniques are based on unisegmental or bisegmental fusion procedures, mostly by anterior decompression of the spinal canal, bone-grafting (with or without cages), and plating. For posterior fixation procedures there are special plate and rod systems available based on pedicle-screw-fixation.

Outcome

The main determinant is the presence or absence of an associated spinal cord injury. Early operative spine fixation facilitates active rehabilitation, which is, for patients with spinal cord injuries of paramount importance.

Professor Dr. Ottmar Trentz
Director of Accident Surgery

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