Athletes returning to play after cervical spine or neurobrachial injury

Injured athletes can present to a spine physician in many settings, such as during an in-office visit or on the field during a competition. Furthermore, the nature of the injury presentation can vary. For example, some athletes report a sudden “pop” in the neck that may be associated with axial or appendicular pain. There may be varying gradations of altered sensations or paresthesiae. Weakness can be subjective or objective.

A wide variety of presentations exist. As such, the approach to theses problems begins with an accurate description of the injury. It is important to note whether the athlete was able to complete the athletic event or if the pain and symptoms were too great to allow continued play. An understanding of the precise mechanism of injury and subsequent immobilization maneuvers is also paramount. A complete neurological examination to detect objective abnormalities of sensation or strength is mandatory. Imaging studies can range from plain radiographs to advanced modalities such as computerized tomography (CT) or magnetic resonance imaging (MRI).

The goal of this evaluation is to formulate the most accurate diagnosis of the traumatic spinal event. This step is crucial to prognosticating the likelihood of subsequent serious spinal injury and influences the decision to return to play. These diagnoses include:

A substantial body of literature has attempted to correlate morphological features of the cervical spine to the risk of neurological injury during sports activity. Most studies have hypothesized that athletes with smaller spinal canals might be more prone to injury.

Kang et al. [5] reported on 283 patients with cervical fractures and dislocations, specifically analyzing the space available for the spinal cord at the level of injury, the sagittal diameter of the canal at uninjured levels and the Pavlov ratio at uninjured levels. The canal measured a mean of 10.5 mm in patients with complete SCI, 13.1 mm in those with incomplete SCI, 15.9 mm with nerve-root injury and 16.7 mm for those without neurological deficit. Statistical differences were found between the groups (P < 0.001), supporting the notion that a larger canal diameter was somewhat protective against injury. At the uninjured level, the mean Pavlov ratio was 0.82 in those with complete SCI and 0.84 for those with incomplete SCI. In those with nerve-root injury, the Pavlov Ratio was 0.96 in patients. These differences were statistically significant (P < 0.005) in that the smaller Pavlov ratio correlated with a higher risk for SCI.

Torg et al. [4, 6, 7] reported on 110 patients that experienced transient neuropraxia from a cervical injury during sports. Importantly, no patient in the study sustained permanent or catastrophic neurological injury. Similar to the Pavlov ratio, Torg described a ratio defined as anteroposterior diameter of the spinal canal/vertebral body (SC/VB) ratio. In their calculations, individuals with smaller SC/VB ratios (0.65 ± 0.1) were more likely to sustain recurrences when compared to those with higher ratios (0.72 ± 0.1). Other findings of interest included that individuals returning to football after an injury had a higher recurrence rate compared to other sports. Ultimately, Torg et al.’s recommendations were that if an athlete completely recovered without complication after one or two episodes of SCN, then he may safely return to play. Those with larger SC/VB ratios were deemed appropriate to return to play as they are least likely to suffer from recurrences. Torg et al. concluded that athletes with mechanically stable spines who have experienced transient paralysis are not at increased risk for catastrophic SCI compared with those who had never sustained transient paresis.

Despite its apparent utility, Torg et al. [4, 6, 7] have not recommended using the SC/VB ratio as a screening mechanism for determining whether an athlete can participate in contact sports. In 1996, Torg et al. reported on the ratio’s poor positive predictive value (0.2%) when using the recommended criterion of 0.80. Therefore, the Torg ratio can help stratify the risk of a neuropraxic event but it is, by itself, not a guideline for athletes return to contact sports [4, 6, 7].

Eismont et al. reported 98 patients with spinal fracture-dislocation and neurological injury after sports injuries [8]. This study differed from the prior studies in that the risk of injury from fractures was assessed. This group studied the sagittal diameter of each cervical vertebra and reported the average values in those patients with complete SCI, incomplete SCI and no deficit (Table 1). Similar to Torg, they found that an athlete with a larger canal was less likely to have a neurological deficit after a spinal fracture or dislocation.

Despite the apparent lack of consensus amongst practitioners and the failure to find a highly sensitive and specific parameter with which to predict those at greatest risk, several authors have elaborated guidelines concerning return to play after injury. For fear of discarding all of these for not being “evidence-based”, one must consider the difficulty in accruing a sound body of evidence on this topic. The following guidelines, therefore, borrow heavily from the authors’ experience, which may be the “best available” information on this topic.

Bailes et al. [9] guided return to play based on the classification of the neurological deficit. Athletes with Type 1 injuries (permanent SCI) were barred from any further participation within the contact sport. Those with Type 2 injuries (transient SCI, usually without radiological findings) were allowed to participate in contact athletic events as long as the injury did not recur. Athletes with Type 3 injuries (neurological deficits in addition to radiological abnormalities) need further enquiry regarding their suitability for return to athletic play. The group also suggested electromyography several weeks after the traumatic injury in order to confirm nerve involvement in injuries involving the brachial plexus.

Morganti [10] associated “transient…neurapraxia…[as] related to forced hyperflexion, hyperextension, or axial compression of the cervical spine”. This perhaps illustrates why Torg’s ratio has a poor predictive value, as it only represents anatomical dimensions and not functional mechanics. Furthermore, it has been reported that 50% of athletes experience brachial plexus neurapraxia at some point in their college athletic careers.

Other studies, have illustrated that a substantial percentage of athletes who have had neurological injury will go on to experience further events throughout their careers [10]. However, it was later found that players returning after full recovery without radiological findings were at no increased risk when compared to asymptomatic athletes in the same sport. In a recent review, Vaccaro et al. [11] synthesized the existing literature to delineate a list of absolute and relative contraindications for return to play (Tables 2–5).