Vertebral Fractures in Children and Adolescents: Difference between revisions

Definition/Description[edit|edit source]

A spinal fracture happens when a vertebral body collapses. When this occurs in the paediatric population and because the bones are still developing, this can therefore can have severe consequences. A vertebral fracture is less obvious compared to a long bone fracture and is often very painful^[1]。

Clinically Relevant Anatomy[edit|edit source]

C- spine:

• Epiphyseal variants
• Epiphyseal plates are smooth and regular and have sclerotic lines
• Unique vertebral architecture
• Incomplete ossification of synchondroses and apophyses
• Hyper-mobility

C1:

• Anterior arch is ossified in only 20% of cases at birth
• Becomes visible as an ossification centre by 1 year of age
• Neural arches appear in 7th foetal week
• Anterior arch fuses with the neural arches by 7
• Non-fusion before this can be mistaken for a fracture
• The neural arches fuse posteriorly by 3 years of age.
• Occasionally, the anterior ossification centre of C1 does not develop and the neural arches attempt to fuse anteriorly- This fusion abnormality can be differentiated from a fracture in that it demonstrates sclerotic margins

C2 (the axis, has the most complex and unique development of all vertebrae):

There are four ossification centres at birth:

• One for each neural arch
• One for the body
• One for the odontoid process

The odontoid process forms in utero from two separate ossification centres that fuse in the midline by the 7th foetal month. A secondary ossification centre appears at the apex of the odontoid process (os terminale) between 3 and 6 years of age and fuses by age 12 years. The body of C2 fuses with the odontoid process by 3–6 years of age. This fusion line (subdental synchondrosis), or the remnant of the cartilaginous synchondrosis, can be seen until age 11 years and may be confused with a fracture. The neural arches fuse posteriorly by 2–3 years of age and with the body of the odontoid process between 3 and 6 years of age^{[3][4][5][6][7]}。C3 through C7 can be discussed as a unit because they exhibit the same developmental pattern.

Three ossification sites are present:

• The body - which arises from a single ossification site
• The two neural arches

The neural arches fuse posteriorly by age 2–3 years, and the body fuses with the neural arches between 3 and 6 years of age. Additionally, secondary ossification centres may be seen at the tips of the transverse processes and spinous processes that may persist until early in the 3rd decade of life and simulate fractures. Secondary ossification centres can also appear at the superior and inferior aspects of the cervical vertebral bodies and remain unfused until early adulthood^{[8][3][4][5][6]}。

Ligaments in the C-spine:

• The anterior and posterior atlanto-occipital membranes extend from the upper aspect of C1 to the anterior and posterior aspects of the foramen magnum.
• The anterior atlantoaxial ligament extends from the anterior midportion of the dens to the inferior aspect of the anterior arch of C1.
• The tectorial membrane is the superior extension of the posterior longitudinal ligament and attaches to the anterolateral aspect of the foramen magnum.
• The transverse ligament extends from the tubercle on the inner aspect of one side of the atlas to the tubercle on the other side.
• The apical ligament lies between the superior longitudinal fasciculus of the cruciform ligament and the anterior atlanto-occipital membrane.
• The alar ligaments connect the lateral aspect of the dens and the medial inferior aspect of the occipital condyles- the main function of the alar ligaments is to limit rotation to the contralateral side^[3][4][7][9]。

Paediatric Versus Adult Cervical Spine[edit|edit source]

Cervical spine injuries in children usually occur in the uppercervical spinefrom the occiput to C3. This fact may be explained by the unique biomechanics and anatomy of the paediatric cervical spine.

• The fulcrum of motion in the cervical spine in children is at the C2-C3 level; in the adult cervical spine, the fulcrum is at the C5-C6 level^[10][11]。
• The immature spine is hypermobile because of ligamentous laxity, shallow and angled facet joints, underdeveloped spinous processes, and physiologic anterior wedging of vertebral bodies, all of which contribute to high torque and shear forces acting on the C1-C2 region.
• Incomplete ossification of the odontoid process, a relatively large head, and weak neck muscles are other factors that predispose to instability of the paediatric cervical spine^{[12][13][14][11][7][5][4]}。

Kyphosis and Lordosis[edit|edit source]

Kyphosisand lordosis are shown to increase at a linear rate from a child to adolescent age.

• 脊柱后凸的曲线增长25°ag)的7年e to 38° at 19 years of age (kyphotic angle = 25° + 0.58 × age)
• Lordotic curves increase from 22° at 5 years of age to 32° at 20 years of age (lordotic angle = 24° + 0.51 × age).
• There were no differences between males and females^[15]。

Epidemiology/Aetiology[edit|edit source]

Spinal fractures make up only 1-3% of all paediatric fractures^[17]。This is less incidence than in the adult population due to the child’s spine being more mobile and elastic and having a smaller mass compared to adults^[18]。Bone structure and strength are considered vital predictors of fracture occurrence^[19]in children and a bone mass reduction of 6.4% doubles the risk of fracture^[20]。The incidence of these fractures are higher in children under the age of 5 and over the age of 10 years^[21]。Spinal fractures in adolescents can have devastating consequences such as spinal deformity,scoliosisandSyringomyelia^[21]。

The cervical spine is the most common location for factures in infants, because of the peculiarity of the anatomy of the infant spine such as having a heavy head and less muscular neck which puts more strain on the spine^[21]。As previously mentioned, the paediatric spinal anatomy is different from the adult's which predisposes children to flexion and extension injuries. Some of these differences include the facet joints being oriented differently leading to greater mobility but worse stability in the spine^[17]。

In a child's spine, there is a high resistance against compression forces largely due to resilient intevertebral discs^[21]。日本曾有一项研究发现高压力分配n in the anterior compartment of children's spines thereby predisposing this area in particular to fractures. Paediatric spinal fractures are normally caused by high impact and speed injuries. These predominantly include: falls, sporting impact injuries and road traffic accidents with the most common fractures being compression fractures where the vertebral bodies collapse.

In a review by Tan et al^[19]bone strength was defined as the ability to resist fractures while taking into consideration extrinsic properties of bones such as mineral mass and distribution of bone mass. Studies provide strong evidence of the relationship betweenphysical activityand bone mass as concentric and eccentric muscle contractions elicited from physical activity place high loads on the skeleton^[19]。Also, fracture incidence was shown to be at its peak in early puberty at 10-12 years in girls and 13-15 years for boys^[20]。

Mechanism of Injury[edit|edit source]

Neck fractures are common in children due to their disproportionately large head in comparison to weak neck muscles, which cause a bending movement on impact that is larger than the neck muscles can protect from. The upper cervical facet joints are also horizontally orientated and shallow with laxity in the ligaments^[22]。Usually ligament laxity prevents injury in other body parts by transferring energy however this property is not shared by the spinal cord^[22]。

Due to the positioning of the paediatric spine and it's increased elasticity from the increased cartilage and intervertebral disc thickness, there has to be a considerable amount of force obtained to cause an unstablefracture^[18]。

• Motor Vehicle accidents – both passengers and pedestrians (Most Common)^[21][22]

• Cycling

• Falls from a height (also common)^[21][22]

• Sporting Injuries^[21][22]

• Assault

Fractures Types[edit|edit source]

Contiguous compression fractures- common in paediatric spinal injury due to the increased C- spine mobility, commonly linked to flexion movements, however increased mobility does mean there is reduced neurological compromise^[22]。

Burst fractures– make up only 10% of all thoracolumbar injuries in paediatrics due to the increase in spinal flexibility, meaning the pressure is not concentrated in one area - the common cause of burst fractures. This also reduces neurological damage along the increased size of the paediatric spinal canal compared to the spinal cord and cauda equina^[22]。

Chance fracture– common in children when wearing lap belts in motor traffic accidents. The seat belt acts as a fulcrum causing hyperflexion, commonly seen alongside intra-abdominal and head injuries^[22]。

Impression fractures^[21]

Apophyseal ring fractures- only found in the paediatric population. Normally seen in adolescents and occurs due to the ring apophysis and the vertebral body not fusing completely and may separate in the process^[23]。

Characteristics/ Clinical Presentation[edit|edit source]

A 10 year report at a children's university hospital found symptoms were as follows:^[21][22]

C-spine Fracture

• neck pain

• neurological deficit

• fixed abnormal head positions

• Common Additional Injuries - facial/head injuries, skull and facial fractures, facial lacerations, intercranial injury

T-spine Fracture

• back pain

• ecchymoses (skin discolouration due to bleeding below skin)

• localised tenderness

• neurological deficit

• Common Additional injuries - simple or multiple rib fractures, fractured sternum, pulmonary contusion, abdominal/visceral injuries including splenic haematoma

L-spine Fracture

• Back pain

• ecchymoses (skin discolouration due to bleeding below skin)

• localised tenderness

• abdominal pain

由于孩子们拥有一个更大的spinal canal than their spinal cord they can tolerate more compression than adults can before neural damage occurs

N/B: Ensure to look for fractures at all levels of the spine (C-spine, T-spine and L-spine) when assessing for potential spinal fracture in children^[21]。

Prevalence^[21][edit|edit source]

• In children below 5 the most common area to injure was T8 followed by lumbar
• Between the ages of 5-10 the most common fracture area was the thoracolumbar region
• In teenagers the most common area begins to shift to the lumbar spine
• From 15 years and older the lumbar area is most affected

Differential Diagnosis[edit|edit source]

• Low Back Pain
• Spondylosis
• 幼年强直性脊柱炎
• 椎间盘突出
• Spinal cord injurywithout radiographic abnormality

Diagnostic Procedures[edit|edit source]

• Sensation of ‘breath arrest’- immediately after the trauma the children would feel extremely short of breath, this is a predictive factor for vertebral fracture, particularly thoracolumbar fractures.

• X-ray– due to the cartilaginous nature of the vertebra, fractures are not always clear from routine x-rays and children can go undiagnosed.

• MRI– used to determine diagnosis of potential fractures shown on x-ray. They give clear images of the vertebra allowing for more accurate diagnosis. This allows for direct visualisation and confirmation of the fracture, where it is in the spine and what type of fracture has occurred.

• CT scan– these have better prognostic ability than x-ray as they show bony details in higher definition than an x-ray. It is therefore more likely to get a clear diagnosis from a CT scan than an x-ray. However, like with x-rays fractures can go unnoticed on CT scans, therefore if there is any doubt about the potential of a fracture it should be followed up with an MRI scan to clarify a potential diagnosis.

• Flexion/Extension C-spine x-rays –often used after CT scans if no findings are present to determine if there is any undiagnosed cervical instability^[24][25][26]

Other Diagnostic Tools:

Nexus criteria——全国紧急状态crite x光利用率组ria assesses low-risk patients for cervical spine injury. It is primarily used to determine if an x-ray is required or if further imaging is needed after an x-ray to determine possible diagnosis.

Nexus criteria^[27]:

• Absence of midline cervical tenderness

• No evidence of intoxication

• Normal level of alertness

• Normal neurological exam

• Absence of a painful, distracting injury

Canadian C-spine Rule– these are a set of guidelines to help a clinician decide if cervical imaging (i.e. x-ray, CT or MRI) are appropriate for trauma patients. For children however, consideration needs to be taken around developmental stage, so applying these rules can be difficult.

C-spine rules^[28]:

1. Any high-risk factors which mandate radiography
   • Dangerous mechanism of injury
   • Age > 65
   • Paraesthesia in extremities
2. Any low-risk factor which allows safe assessment of range of motion
   • Simple rear-end motor vehicle collision
   • Sitting position in ED
   • Ambulatory at any time
   • Delayed onset of neck pain
   • Absence of midline spine tenderness
3. Able to actively rotate neck
   • 45度左右对吗t

Management[edit|edit source]

Conservative Management^[18]

• Casting- There are two types: Minerva and Plaster and they usually stay on for a period of around 2 months

• Halo Vests- to be worn for an average of 8 weeks

• Bed Rest- until acute symptoms subside, followed by a moulded body cast

Conservative management, particularly of wedge fractures without neurological lesions can be successful, leaving only moderate residual deformities. However, it is important there is an accurate diagnosis to confirm the stability of the fracture to ensure accurate treatment is provided.Whilst nonoperative treatment is viable for burst fractures in children with no neurological deficits and minimal initial kyphosis, operative treatments are recommended for unstable burst fractures to correct the deformity.

Angelliaume et al, 2017[29]:

• In a case of a stable spinal fracture withoutneurologicaldeficiency, conservative treatment must be the first treatment of choice in children
• The significant difference between the initial and the final local kyphosis at the thoracic level was not found for the lumbar level.
• It is hypothesized that the brace is more efficient at the thoracic level than at the lumbar level and enables more remodelling, decreasing compressive forces by an antikyphotic effect- furthermore, it is easier to correct a thoracic kyphosis than a lumbar one using an antikyphotic brace

Functional outcomes:

• Functional results indicated a high rate of back pain.
• 然而, patients’ functional results were satisfactory because they reported no limitations in their daily life activities and did not use painkillers.
• Variable rates of functional outcomes have been reported, with 12–57% incidences of back pain after a conservative treatment
• 然而, rates of back pain in adolescents without back injury are also high, with a prevalence of 7–70% .

Surgical Management

Overall surgical interventions depends on the type and severity of the fracture. The Denis classification can be used to differentiate between a stable and a unstable vertebral fracture which can help decide on management options. Generally according to the evidence, lots of stable fractures can be treated conservatively however unstable fractures will require surgical management^[30][18]。Furthermore if the patient has a neurological deficit or a spinal cord injury, surgery is necessary to stabilise the fracture and gain neurological function^[31]。Surgical outcomes within the population have been positive. Vander et al^[32]found surgical intervention was positive in ensuring the correction of the kyphosis of the spine compared to conservative management that which led to worsening of kyphosis.

Types of surgery can vary depending on the type of fracture and the age. Adolescents can be treated using adult type instrumentation due to a more developed spine^[30]而, younger children have smaller pedicles so a normal screw placement in this area can be challenging^[30]。Evidence suggests a shorted fusion is the prefered approach in peadiactric fractures in order to preserve growth and mobility^[33]。In the lumbar spine, lumbar fusion can be used which involves fusing the vertebral bodies together so no movement can occur between them enabling the fracture to be repaired, this can be managed via a posterior approach^[34]。If the fracture is more severe reconstruction surgery such as vertebroplasty or kyphoplasty can take place^[34]。Although conservative management has been proven to correct initial conditions and deformities, these deformities can return overtime leading to a short term fix as opposed to a long term fix.

Prevention[edit|edit source]

Over recent years there has been an increased recognition of the need to identify children with bone fragility^[35], this is due toosteoporosisbeing thought to root from childhood therefore preventative efforts should be initiated in early life to ensure life-long bone health^[36]。

• Calcium: intake during infancy, childhood and adolescence contribute to bone mass gain. Dietary supplementations may be offered to those who cannot take in enough calcium^[36]。

• Vitamin D:testing for vitamin D deficiency is recommended for those who have recurrent traumatic fractures even on low-impact^[36]。

• Mechanical loading and weight bearing exercise: puts force on the skeleton that increases bone formation^[36]。

Dual Energy X-ray absorptiometry (DXA) is considered the gold standard for the assessment for bone mass as it is preferred due to low radiation^[36]。It is reported that an association occurs between low bone mass measured using DXA and increased fracture risk in children^[36]。

There is a need to assess each child on an individual basis to identify if they need a bone health evaluation. In the diagram below,^[36]it can be seen what health factors should be considered in the decision of whether to conduct a bone health evaluation^[35]。

An additional consideration is road traffic safety. Leonard et al^[22]found in their study of paediatric spinal trauma that children who were restrained by a lap belt in the rear of a vehicle whereby a head on collision occurred led to hyperflexion of their spine and resulting in intra-abdominal and head injuries^[22]。To prevent these injuries from occuring, it is recommended that cross-body seat belts and booster seats be used to strap chiodren in vehicles.

References[edit|edit source]