Introduction

Injuries to the spine and spinal cord are less common in children than adults. The injuries have different distributions and frequency in different-aged children, dependent upon the developmental, anatomical and physiological differences with age. Children account for up to 10% of all spinal injuries, but the mortality among spine-injured children is higher than in adults, with estimates ranging from 25–30%, with death most often due to associated injuries to other organs, especially the brain.¹

The incidence of spinal cord injury amongst spine-injured children is probably about 1%.^1,2 In neurologically impaired survivors the injuries are most commonly at the C1–C2 level, or in the lower cervical or thoracic spine.¹ The common causes of spine and spinal cord injuries in children are motor vehicle crashes, falls, diving accidents, sports injuries and, occasionally, non-accidental injury.^1,3,4

The majority of injuries in children occur in the cervical spine. In children under 8, most (about 80%) occur in the C1–C3 region, whereas after 8 years of age the incidence is similar to that in adults, with the majority in the lower three cervical vertebrae.^2,5,6 The thoracolumbar junction is the most commonly injured area outside the cervical spine, with the thoracic and lumbar spines having roughly equal incidence of about 25%. There is an increased incidence of neurologic injury in fractures of the thoracolumbar junction. The relatively high incidence of injuries in this region is due to the large range of motion and the changing orientation of the facet joints.^1,7 Approximately 30% of patients with spinal cord injury have fractures at more than one spinal level. A majority of these are in contiguous vertebral segments, but 5–15% may be in different regions.⁷

Developmental anatomy and physiology

There are a number of injury patterns of the spine – and especially the cervical spine – that are unique to children. In order to understand the differences between adult and paediatric spine injuries knowledge of the developmental anatomy of the spine is essential.

The large amount of cartilage present in the paediatric cervical spine can make radiographic evaluation difficult. This is especially true in the first few years of life, and in the upper cervical vertebrae.

The atlas ossifies from three ossification centres: two ossification centres of the lateral masses and one ossification centre for the body. The ossification centre for the body does not ossify until about 1 year of age. The posterior arches fuse by 3 or 4 years of age, while the synchondrosis between the lateral masses and the body fuses at approximately 7 years of age.^3,5

The axis ossifies from seven ossification centres. The five primary ossification centres are two for the lateral masses, two for the odontoid (which are usually fused at birth but occasionally persist as a dens bicornis), and one for the body. The odontoid is separated from the body by a synchondrosis, which fuses between 3 and 6 years old. The two secondary ossification centres are the tip of the odontoid process (which appears at about 3 years of age and is usually fused by 12 years of age), and the inferior ring apophysis (which, like other ring apophyses, generally ossifies after 8 years of age and fuses in the early 20s).^3,5

The remainder of the cervical vertebrae each contain three primary ossification centres, one for the body and one for the two neural arches, and two secondary ossification centres, the ring apophyses. The neural arches fuse posteriorly by the age of 3, and anteriorly the three ossification centres fuse between 3 and 6 years of age. Importantly, the vertebral bodies are wedge-shaped until the age of 7 when they begin to square off.^3,4

The thoracic and lumbar spines develop in a similar way, with secondary ossification centres for the spinous process and the transverse processes added. By the time the child is 8–10 years of age the spine has reached near-adult size.^3,4

There are a number of other differences of importance for the spine. The fulcrum of movement of the neck is located at C2–C3 in the infant, at C3–C4 by the age of 6, and by the age of 8 the fulcrum is at C5–C6, as it is in the adult. There is a relatively large head and weak neck muscles; laxity of the ligaments and joint capsule; and relatively horizontal positioning of the facet joints with underdevelopment of the uncinate processes.^1,3,4 All these features increase the risk of injury to the child’s spine.

Initial assessment

All patients with significant trauma should be assumed to have a spine or spinal cord injury and appropriate precautions must be taken to prevent further exacerbating any possible injury. The initial assessment of patients with potential spine or spinal cord injury should be directed at the airway, breathing and circulation, in line with trauma resuscitation guidelines (see Section 2). The patient should be stabilised and a thorough secondary survey performed. At this point all possible spine and spinal cord injuries should be identified. The lateral cervical spine X-ray will be done at this stage in patients with major trauma. Thorough radiological assessment of the injuries should be completed once resuscitation and stabilisation and the secondary survey have all been accomplished.

A thorough history of mechanism of injury, previous spinal injury, other illnesses, particularly respiratory illness (acute or chronic), cardiac illness, or bone disorders, medication and allergies is needed to determine the patient’s premorbid physiological status.

Spinal immobilisation

Spinal immobilisation is currently a controversial issue, especially in young children. A balance must be found that will diminish the risk of further injury to the child’s spine, but not interfere with the assessment, or the normal physiological functions, of the child. Traditionally the spine has been immobilised in a rigid cervical collar, on a spine board with a head immobiliser and straps, or with sandbags and tapes, thus providing adequate control of the entire spine (Table 24.3.1).^3,8,9

There are a number of potential problems with this immobilisation (Table 24.3.2). Cervical collars are not made to fit infants and alternative immobilisation is needed. An ill-fitting collar may cause the chin to become trapped under the chin support and may cause airway obstruction. The young child may become distressed from being rigidly immobilised, making further assessment difficult, and potentially raising intracranial pressure. Rigid immobilisation in a collar and head immobiliser on a spinal board has also been shown to decrease tidal volume and respiratory excursion.¹⁰ In addition, because the young child’s head is disproportionately large, the neck is flexed when immobilised on a standard spinal board. This causes flexion of the cervical spine, which may cause movement at the site of injury. To prevent this, a spinal board with a recess for the head or padding that elevates the torso is needed for children less than 8 years old (Fig. 24.3.1).^11–13

Fig. 24.3.1 Effects of spine-board on cervical spine position in children.

Child immobilised on a standard backboard (A), and on backboards modified with an occipital recess (B) and a mattress pad (C).

Modified from Herzenberg et al 1989 Emergency transport and positioning of young children who may have an injury of the cervical spine: The standard backboard may be hazardous. Journal of Bone & Joint Surgery 71(1): 15–22.

A number of different cervical collars are available and satisfactory to use. The clinician must be familiar with the method of sizing and applying the collar available, as an incorrect fit will allow too much movement of the collar if too small, or will produce a distraction of any existing injury if too large.

For children who have less major trauma but are at risk of spinal injury, a degree of judgement is needed by the clinician as to the level of immobilisation that is appropriate. However, in all patients with multiple or significant other injuries immobilisation is still recommended. If the child is not on a spine board, immobilisation solely in a cervical collar, maintaining alignment of the neck and the entire spine, is appropriate. Using sandbags and tape or other means to immobilise the head by fixing it to the bed risks further complications, including airway compromise, and the risks are likely to outweigh the benefits.^14,15

The back is examined by log rolling the child. This requires at least three people in the smallest of children, and up to five in larger patients. The child is freed from the head immobiliser and any strapping to the spinal board removed. One person must stabilise the cervical spine by supporting the head and neck in the neutral position throughout movement. No traction should be applied to the neck. The other team members control the shoulders, hips and legs, and one person must be free to inspect and palpate the back. The back is inspected for bruises, abrasions, wounds or deformity of the spine. The spinous processes are palpated for tenderness. The back of the neck and head and the buttocks and anus should be inspected. A rectal examination is not mandated in all children.

To limit discomfort and the likelihood of pressure sores a child should be kept on the spinal board for the shortest possible time. Once resuscitation and urgent procedures and investigations are completed the board should be removed. This is especially important in patients with suspected spinal cord injury.¹⁶

Cervical spine injuries

As the cervical spine is the most common region injured and accounts for the majority of spinal cord injuries, a thorough knowledge of injuries in this region and the appropriate assessment of the spine both clinically and radiographically is mandatory. In children younger than 8 years of age the majority (but not all) injuries occur above the fourth cervical vertebra. After 8, the pattern of injury is similar to that seen in adults (the majority of injuries below C4).^2,17