Spondylolysis is fairly frequent in sporting children and teenagers. It occurs in almost half the cases consulting for lumbar pain. It can happen both with repetitive and acute trauma, mostly when subjected to flexion and hyperextension forces. It is typical in soccer players, gymnasts, swimmers, and pool divers.

It originates on a pars articularis defect on the vertebral posterior elements.

Although it can affect any level, it tends to involve L5 85–95 % of the times (the rest is mostly L4). It can be uni- or bilateral. When unilateral, a compensatory contralateral sclerosis can be seen; it should not be mistaken for other pathologies such as osteoid osteoma.

Plain lumbar spine radiographs in four views (anteroposterior, lateral, and both obliques) are required. Oblique views are needed since up to 20 % of cases are only seen in them. Interruption of LaChapelle’s or Scotty dog’s neck is the classical sign. A lateral radiograph may show an associated spondylolisthesis.

Given the high incidence in young sportswomen and men, if the plain radiographs are normal but the suspicion index is high, other diagnostic tools (bone scan, CT, or MRI) that could additionally detect other pathologies such as infection or osteoid sarcoma should be used.

MRI is able to determine early edema before a complete defect occurs (allowing a better response to conservative treatment). The lack of ionizing radiation for MRI makes the technique of choice to evaluate spondylolysis.

The lateral radiograph shows a normal vertebral alignment, without L5 spondylolisthesis (anterior displacement) (Fig. 1.5). It is in the oblique views (Fig. 1.6) where the pars articularis defect is noted as a fracture line (arrow) in LaChapelle’s dog’s neck.

MRI proved relevant edema both in the pars and in the pedicles as seen in sagittal STIR (Fig. 1.7) and T2-weighted axial views (Fig. 1.8). Also, the bilateral spondylolysis can be appreciated as a bilateral defect in L5’s pars interarticularis (arrow) in the axial views.

Isolated spinous process fractures (Clay-shoveler fracture) are fairly infrequent, and they are generally considered stable. However, they can also be associated to more significant lesions depending on the forces involved.

They were first described in Western Australia among strenuous physical laborers. They have been reported in American football, volleyball, power lifting, golf, cycling, diving, skiing, ice hockey, wrestling, and gymnastics and, anecdotally, among Nintendo Wii players and indoor rock climbers.

They usually occur at lower cervical/ upper thoracic levels. Mechanisms of injury include hyperflexion, hyperextension, rotation, or repetitive stress. In these cases the para- and supraspinous musculature and ligaments can avulse the spinous process. When caused by a direct blow, they may be associated to other more serious injuries or extend into the laminar regions. In high-risk incidents, exquisite care should be taken to rule out unstable injuries capable of spinal cord or nerve root damage.

Plain radiography (AP, lateral, and odontoid views) constitutes the initial investigation of choice. A ghost sign, where a double spinous process is seen on the AP view, results from displacement of the fracture.

Patients with associated injuries or presenting after a high-risk mechanism of injury or those showing radiological abnormalities on initial studies require CT investigation with coronal and sagittal reformatted views.

MRI is useful in investigating suspected muscular, ligamentous, and spinal cord injuries. CT and/or MR angiogram are required to discard vascular injuries.

Isolated spinous process fractures are almost always managed conservatively with rest, analgesia, and immobilization during the painful period followed in due course by physical therapy. They may become chronically symptomatic in particular if nonunion is present.

Our player’s management included soft collar immobilization for 10 days. Jogging was introduced on day 15 post injury and more complex football drills on his own at day 40. He was discharged back to full training at day 72.

The axial (Fig. 1.9) and sagittal reconstruction CT (Fig. 1.10) show the C7 spinous process fracture.

The axial fat-suppressed FSE T2-weighted MR image (Fig. 1.11) shows the fracture and surrounding edema (arrows).

The sagittal fat-suppressed FSE T2-weighted MR image (Fig. 1.12) shows the fracture with no other acute injury related.

Cycling accidents are the most common cause of head injury in older children and teenagers. While most of them are mild, detecting intracranial lesions requiring extended management is paramount. The choice of diagnostic imaging techniques is dictated by clinical findings and evaluation including a Glasgow Coma Scale.

Contrary to adults, in smaller children, due to the head’s larger relative volume and the skull’s increased flexibility and fragility, a lower energy impact can lead to skull fractures. Plain radiography can detect most of them (seen as radiolucent linear images). A fracture increases the chances of intracranial lesions, but its absence does not exclude significant parenchymal damage, so plain radiography is not useful as a screening tool. Over 50 % cases combine intracranial lesions with normal plain radiographs, and about half detected skull fractures are associated to intraparenchymal injury.

CT’s speed and ability to detect acute traumatic lesions make it the investigation of choice to diagnose and follow up pediatric head injuries. If the fracture is parallel to axial cuts, multiplane 3D reconstructions or MIP (Maximum Intensity Projection) may be required.

Intra-axial lesions are mostly constituted by contusions, intraparenchymal hematomas, and shearing lesions.

In children, the greater cranial flexibility increases the risk for intraparenchymal damage. This can be caused by either direct trauma or secondary to acceleration–deceleration mechanisms. Their main locations are as follows: temporal lobe (temporal pole, inferior temporal region and adjacent to the Sylvian fisure), frontal lobe, frontal lobe (inferior frontal region), and parasagittal areas.

Contusions are seen in CT as poorly defined, low-density areas. Hyperdense foci can be noted in superficial gray matter if hemorrhage is present.

MRI has a greater sensitivity in detecting nonhemorrhagic contusions: FLAIR sequence on MRI shows cortical edema, while T2 echo-gradient sequence detects chronic hemorrhage and hemosiderin deposits.

Helicoidal CT without contrast shows a left temporal fracture (arrow) with overlapping on the bony window (Fig. 1.13). A volumetric 3D reconstruction is performed to better appreciate the whole fracture (arrow) (Fig. 1.14). The parenchymal window (Fig. 1.15) shows hemorrhagic contusions (highly attenuated foci) in right basal frontal (arrow) and anterior temporal regions with perilesional vasogenic edema.

MRI: a cortex/subcortex fuzzy lesion, mostly hyperintense, with decreased signal in relation to hemosiderin (arrow) in the right anterior frontal and temporal regions compatible with evolving trauma is noted on the T2-weighted coronal plane (Fig. 1.16).

Head trauma during soccer practice is more common among the 10–14 age group. The main mechanism of injury tends to involve a direct collision with another player, specifically, head to head. In the 5–9-year-old age group, there is a high proportion of head trauma caused by goal post-impact.

In addition to intraparenchymal damage, cranial trauma can be associated to extra-axial blood collection, both epidural and/or subdural.

A posttraumatic epidural hematoma is a blood collection between the dura mater and the internal skull table. It is most usually located in the temporoparietal region. It occurs in 1–3 % of moderate to severe head trauma in children.