Diagnostic Imaging of Sports-Related Spinal Disorders



Diagnostic Imaging of Sports-Related Spinal Disorders


Mitchel B. Harris, MD, FACS

Micah Blais, MD


Dr. Harris or an immediate family member serves as a board member, owner, officer, or committee member of the North American Spine Society. Neither Dr. Blais nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article.



Introduction

Spinal injuries in athletes range widely in terms of severity, etiology, and the acuity with which diagnostic imaging should be obtained. Sports-related activities are the second most common cause of subaxial cervical spine injuries, behind only motor vehicle collisions.1 Although these injuries are relatively uncommon, they can be associated with significant morbidity and mortality and often require urgent imaging.2 On the other end of the spectrum, lumbar disk herniation is a commonly seen injury pattern in older athletes that rarely requires imaging in the acute setting.3 The objective of this chapter is to highlight injury patterns that are commonly seen in athletes of all ages and to identify current, evidence-based approaches to management and decision making regarding imaging. We will approach these disorders by grouping the conditions into two major categories: (1) acute and traumatic and (2) chronic and atraumatic (Table 6-1).


Acute and Traumatic Conditions


Cervical Spine Trauma

Cervical spinal cord injury (SCI) is a relatively uncommon yet potentially devastating injury associated with participation in sports. In a review of the National Center for Catastrophic Sports Injury Research database, Boden et al estimated the incidence of catastrophic cervical spine injury in high school and college football players to be 1.10 and 4.72 per 100,000 participants respectively.4 Although hockey, wrestling, and rugby are also associated with cervical spine trauma, football is the most commonly implicated sport in the United States. The incidence of sports-related catastrophic SCIs has decreased over the past 30 years because of multitude of factors, including rule changes regarding “spearing” tackling techniques and athlete education.5 Despite these improvements, these injuries still occur and are associated with significant morbidity and therefore require appropriate management and imaging to ensure optimal patient outcomes.

The initial management of acute cervical spine injury should be managed in the same way as any other trauma patient, with focus on adherence to Advanced Trauma Life Support (ATLS) protocols. Specific concerns regarding on-field management and helmet removal techniques are covered elsewhere in this text. Much research effort has been devoted toward the development of systematic approaches to imaging of adult spine injury in the
emergency department (ED) setting. The two most commonly used approaches are the Canadian C-spine rules and National Emergency X-radiography Utilization Study (NEXUS) criteria.6 These guidelines are systematic and evidence based and provide a high level of sensitivity in detection of cervical spine injury.7 Although only a small percentage of ED complaints are sports related, these algorithms should provide a foundation for decision making regarding imaging for adult athletes with concern for cervical spine injury. It is important to note, however, that the applicability of these rules to the athletic population is not absolute and still requires interpretation on the part of the provider. For example, cervical neurapraxia (also known as a “stinger” or “burner”) is a common injury sustained while playing football that results in paresthesias involving the upper extremities and is often the result of an axial load to the head. Strict application of the Canadian C-spine rules to such a patient would identify two “high-risk factors” that would mandate radiography. In actuality, these patients are rarely acutely imaged, and the symptoms usually resolve without incident.








TABLE 6-1 Differential diagnosis of lower back pain in athletes










Spinal Diagnoses Nonspinal Diagnoses
Muscle or ligament strain
Degenerative disk disease
Isthmic spondylolysis (no slip)
Isthmic spondylolisthesis
Fact syndrome
Ring apophyseal injury (adolescents)
Sacral stress fracture
Central disk herniation (without radiculopathy)
Sacralization of L5 or transverse process impingement
Facet stress fracture
Acute traumatic facet fracture
Discitis or osteomyelitis
Neoplasm
Intrapelvic or gynecologic (e.g., ovarian cysts)
Renal disease
Sacroiliac joint dysfunction
(From Bono CM: Low-back pain in athletes. J Bone Joint Surg Am. 2004;86-A(2):382–396 with permission.)

Although NEXUS and the Canadian C-spine rules provide a useful approach to management of adult (athletic) cervical spine trauma, their applicability to pediatric athletes (particularly those younger than the age of 8 years old) is questionable.8 Children younger than the age of 8 years old have a more horizontal orientation of their facet joints, which allows for greater flexion/extension mobility. Additionally, younger children have wedge-shaped vertebral bodies as well as incomplete fusion of vertebral synchondroses.9 Therefore, the fulcrum of cervical spine flexion/extension is more cranial in children younger than the age of 8 years (C2–C3) and moves more caudally as the spine matures until reaching a level of C5 to C6 in adolescence.10 The net effect of this shift is that whereas children younger than 8 years old are more likely to sustain injuries at or above C3, older children are typically injured below this level. Leonard et al retrospectively identified patient factors that are associated with the presence of cervical spine injury in pediatric trauma patients.11 However, even in the presence of one or more of these factors, an evidence-based approach to imaging pediatric patients has not yet been developed. As a result, many individual pediatric emergency centers have attempted to implement institutional-level protocols for imaging patients with suspected cervical spine trauma (Figure 6-1). Although studies have shown that these measures have decreased the amount of time elapsed between presentation and collar clearance, their applicability in terms of a decision-making tool for imaging remains uncertain, and their deployment is far less universal than the adult protocols.12

For providers evaluating pediatric patients with suspected cervical spine injury, the initial evaluation usually includes a thorough physical examination and plain film radiographs of the cervical spine (anteroposterior [AP], lateral, and odontoid views).13 Flynn et al found that MRI can be useful in evaluation of pediatric patients, particularly in evaluating obtunded patients or patients with equivocal radiographs.14 Although CT is more sensitive than MRI in detecting bony injury in the cervical spine, it is less commonly used in pediatric patients because of concerns surrounding radiation exposure.
Additionally, Adelgais et al found that the use of helical CT in the ED setting was associated with increased ED lengths of stay and research usage (see Figure 6-1 and Boxes 6-1 and 6-2).15






FIGURE 6-1 Pediatric imaging algorithm: conscious (A) and unconscious (B). AP = anteroposterior, CSI = Cervical Spine Injury, ROM = range of motion. (Adapted from Lee SL, Sena M, Greenholz SK, Fledderman M: A multidisciplinary approach to the development of a cervical spine clearance protocol: Process, rationale, and initial results. J Pediatr Surg 2003;38(3):358–362.)

Cervical nerve root neurapraxias are the result of acute cervical spine trauma with resulting numbness and tingling involving the upper extremities. They represent the most common peripheral nerve injuries, and up to 50% to 65% of college football players have reported experiencing these injuries at least once in their careers.16 Even though these injuries are commonly seen among athletes, a fair amount of debate exists within the medical community in regards to deciding between allowing immediate return to play (RTP) versus further workup and imaging. The first step for the provider is to distinguish a routine “burner” or “stinger” from a more dangerous condition. Specifically, involvement of more than one extremity, involvement of the lower extremities, associated headache or altered mental status, significant neck pain, or decreased neck range of motion (ROM) should all raise concern for possible fracture or associated SCI (or both), and the patient should be managed with spinal precautions pending further imaging.17

Athletes who experience true “burners” or “stingers” present with sensations of pain or numbness involving a single upper extremity. The exact mechanism of nerve stretch or injury is unclear, but it is believed to be attributable either to traction on the peripheral nerve at the level of the brachial plexus or impingement at the level of the exiting nerve root. The symptoms are typically transient and quite often will have resolved by the time that the patient comes off of the field of play for evaluation.18 Although little evidence exists regarding the management of these injuries, RTP without imaging can be considered in an athlete who sustains his or her first “burner” and is also found to have the following: normal neurovascular examination results; normal, pain-free cervical spine ROM; normal pain-free shoulder ROM; and a negative Spurling’s test result.19 Imaging should be considered in athletes with recurrent episodes, persistent symptoms, or symptoms involving more than one extremity.17 In patients with recurrent or persistent pain, paresthesias, or weakness involving a single upper extremity, MRI or electromyographic studies can be obtained to further localize the level and site of compression.20 Despite this relatively clear distinction, Levitz et al evaluated 55 athletes with recurrent “burners” and found that 53% had cervical stenosis and 87% had evidence of disk disease on MRI.21

It is also important for the managing provider to distinguish between cervical nerve root and cervical cord neurapraxia (CCN). CCN is a afar less commonly seen condition compared with root neurapraxia, with one estimate at only 7 per 10,000 football participants in the United States.22 It is commonly associated with participation in sport and presents as bilateral loss of sensation with or without associated motor deficits that can range from mild to complete. This entity is commonly associated with spinal stenosis; therefore, the provider should obtain advanced imaging (either CT myelogram or MRI) to assess for the degree of functional canal space available.23,24 Because of this association with canal stenosis, isolated CT or plain film evaluation of patients with bilateral symptoms is insufficient.

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Oct 15, 2018 | Posted by in SPORT MEDICINE | Comments Off on Diagnostic Imaging of Sports-Related Spinal Disorders
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