Cervical Spine and Brachial Plexus Injuries: Return-to-Play Recommendations

Joseph S. Torg, MD; Julie A. Ramsey-Emrhein, MEd, ATC

THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 7 - JULY 97

In Brief: Great care is required in managing cervical spine and brachial plexus injuries. Athletes who suffer one or more burners (transient brachial plexus injuries) may return to contact activity when they are asymptomatic and neurologically normal and have full cervical motion. A vertebra displaced horizontally more than 3.5 mm or rotated more than 11° is an absolute contraindication to contact sports. Cervical cord neurapraxia is generally benign, but patients should be counseled about the probability of recurrence, depending on the spinal canal/vertebral body ratio. Unresolved spear tackler's spine is an absolute contraindication to collision sports, as are axial-load teardrop fracture and cervical spine fusion of more than three levels. Spinal cord resuscitation can include blood pressure maintenance and timely methylprednisolone.

All athletic injuries require careful attention, but evaluation and management of injuries involving the cervical spine and brachial plexus require particular caution. Possible nervous system involvement creates a high-risk situation with little room for error, particularly in athletes playing contact sports. An accurate diagnosis is imperative, and decisions about an athlete's return to contact activity should be based on clear criteria derived from data on athletic injuries to the cervical spine, spinal cord, and brachial plexus.

Regarding return to play, these injuries and associated problems fall into three general categories:

• No contraindication: Experience and data indicate no increase in risk of serious injury.
• Absolute contraindication: Experience and data clearly indicate an increase in risk of serious injury.
• Relative contraindication: There is no clear evidence of an increase in the risk of serious injury, but sequelae may include recurrent injury or temporary, noncatastrophic injury. The player, coach, and parents must understand that there is some risk and agree to assume it.

The recommendations for return to play presented here are based on data from over 1,200 cervical spine injuries documented by the National Football Head and Neck Injury Registry (1-3), a review of the literature, an understanding of recognized injury mechanisms (4), and the authors' experience. The more common cervical spine conditions are discussed below, and a more complete list of conditions, classified by return-to-play recommendations, is presented in table 1.

Table 1. Cervical Spine Conditions Classified According to the Authors' Recommendations for Participation in Contact Sports
No Contraindication to Participation* Resolved burner Spina bifida occulta Type 2 Klippel-Feil congenital one-level fusion Developmental stenosis of spinal canal (canal/vertebral body ratio <0.8) Mild ligamentous sprain with no laxity Healed, stable compression fracture of vertebral body Healed, stable end-plate fracture Healed "clay shoveler's" fracture Healed intervertebral disk bulge Stable, one-level anterior or posterior surgical fusion Relative Contraindications to Participation* Recurrent acute and chronic burners Developmental canal stenosis with:    - episode of cervical cord neurapraxia    - intervertebral disk disease    - MRI evidence of cord compression Ligamentous sprain with mild laxity (<3.5 mm anteroposterior displacement and 11° rotation) Healed, nondisplaced Jefferson fracture Healed, stable, mildly displaced vertebral body fracture without a sagittal component or neural ring involvement Healed, stable neural ring fractures Healed intervertebral disk herniation Stable, two-level anterior or posterior surgical fusion	Absolute Contraindications to Participation Odontoid agenesis, hypoplasia, or os odontoidium Atlanto-occipital fusion Type 1 Klippel-Feil mass fusion Developmental canal stenosis with:    - ligamentous instability    - cervical cord neurapraxia with signs or symptoms lasting more than 36 hours    - multiple episodes of cervical cord neurapraxia Spear tackler's spine Atlantoaxial instability Atlantoaxial rotatory fixation Acute cervical fracture Ligamentous laxity (>3.5 mm anteroposterior displacement or 11° rotation) Vertebral body fracture with a sagittal component Vertebral body fracture with associated posterior arch fractures and/or ligamentous laxity Vertebral body fracture with displacement into the spinal canal Healed fractures with associated neurologic findings or symptoms, pain, or limitation of cervical range of motion Intervertebral disk herniation with neurologic signs or symptoms, pain, or limitation of cervical range of motion Anterior or posterior fusion of three or more levels
*Provided individual is asymptomatic and neurologically normal and has full range of pain-free cervical motion.

Diagnostic Considerations

Most serious injuries to the cervical spine result from axial loading, as in spear tackling in football. Fortunately, few athletes have more than transient neurologic episodes, and even fewer incur permanent paralysis.

An athlete with a significant injury will usually have a slight torticollis (wry neck posture), limitation of cervical motion, and, if the condition is chronic, atrophy or decreased cervical paravertebral muscle bulk. A patient with torticollis, decreased range of cervical motion, and cervical muscle atrophy requires a complete neurologic examination and a radiographic study, including anteroposterior (AP), lateral, oblique, open-mouth, and lateral flexion and extension views. If the findings persist or if the patient presents acutely with neurologic signs and symptoms, a magnetic resonance imaging (MRI) study should also be performed.

Brachial Plexus and Nerve Root Neurapraxia

Acute, transient brachial plexus injuries, often called burners, are typically traction neurapraxias occurring in younger athletes as a result of shoulder depression and lateral neck deviation away from the side of injury (figure 1) (5). Chronic recurrent root neurapraxia, typically occurring in older players, results from compression of the nerve root in the intervertebral foramina secondary to hyperextension and ipsilateral deviation of the head and neck (6). Frequently the symptoms can be reproduced by Spurling's maneuver (figure 2). Nerve root neurapraxia is characteristically associated with foraminal stenosis (figure 3) and/or degenerative disk changes (figure 4), often in combination with developmental cervical stenosis.

Athletes who experience one or more burners should wear a cowboy collar (figure 5) to prevent extreme hyperextension and lateral bending of the cervical spine and should undertake a year-round neck and shoulder strengthening program. They may return to collision activities when they are asymptomatic, have normal strength, are neurologically normal, and have a full range of painless cervical motion. Recurrent burners do not increase the risk of a more serious neck injury.

Strains, Sprains, and Disk Injuries

Mild injuries to the ligaments, paravertebral muscles, and intervertebral disk are rarely associated with neurologic signs and symptoms. An injured player will initially complain of neck pain and have limited range of cervical motion. After appropriate treatment, these individuals may return to activity when they are asymptomatic, have normal muscle strength, and have a full range of pain-free cervical motion.

In individuals with injuries involving minor ligamentous laxity, the situation is less clear. Albright et al (7) showed that 10% of freshman football recruits at the University of Iowa demonstrated "abnormal motion." This finding is consistent with our experience and suggests that some high school and college football players may have minor laxity without apparent adverse effects. The degree of acceptable instability or laxity is, of course, the question.

Though no available research sets the upper limits of instability clearly enough for clinical use, the work of White et al (8) is helpful. Using lateral radiographs, they clearly demonstrated that a vertebra displaced horizontally more than 3.5 mm or rotated more than 11° relative to an adjacent vertebra represents spinal instability—certainly an absolute contraindication to further participation in collision activities. Less vertebral displacement or rotation can be considered a relative contraindication, depending on the athlete's level of performance, physical habitus, playing position, and results of imaging studies to rule out disk disease or occult fractures (figure 6: not shown). An experienced sports medicine orthopedist should be consulted to assist in deciding if participation is safe.

Acute cervical disk disease associated with limited cervical motion and/or neurologic signs and symptoms is an absolute contraindication. However, chronic degenerative disk changes (figure 7: not shown) in individuals who are neurologically normal and have full muscle strength and range of cervical motion are a relative contraindication.

Cervical Cord Neurapraxia

Our research has previously described cervical cord neurapraxia (CCN) as a distinct clinical entity and, using x-ray measurements, has identified the cause as developmental narrowing of the AP diameter of the cervical canal in combination with acute mechanical deformation of the spinal cord (9).

The typical clinical case involves an athlete who has an acute transient neurologic episode of cervical cord origin. Neurologic findings may include both arms, both legs, all four extremities, or an ipsilateral arm and leg. The symptoms may result in sensory changes with or without motor findings. Sensory changes include burning pain, numbness, or tingling; motor changes consist of weakness or complete paralysis. An episode usually lasts less than 15 minutes, although some cases may take up to 48 hours to resolve. Complete motor function and full, pain-free cervical motion normally return.

'Pincers' mechanism. The relationship between developmental cervical canal narrowing and CCN has been clearly established (10). In the presence of cervical canal stenosis, CCN results from cord compression due to a "pincers" mechanism (figure 8). This mechanism occurs when hyperextension of the cervical spine causes the posterior inferior aspect of the superior vertebral body and the anterior superior aspect of the lamina of the subjacent vertebra to come together; conversely, in flexion the lamina of the superior vertebra and the posterior superior aspect of the subjacent vertebral body come together. In both cases the approximation causes a sudden decrease in the AP diameter of the canal at that cervical level, resulting in compression of the spinal cord.

The relationship between temporary neurologic dysfunction and cord deformation has been explained through the study of a squid axon injury model. Torg et al (11) correlated the clinical findings of reversible cord deficits with the histochemical response of isolated neural and vascular elements subjected to controlled mechanical deformation. Neurologic recovery from mechanical deformation is inversely proportional to a rise in the intracellular calcium ion concentration, which is directly proportional to the amount and rate of tension applied to the cervical cord. CCN appears to involve rapid cord deformation without loss of spinal stability or cell damage, and recovery of axonal function is not impeded by the deleterious effects of local anoxia from venous spasm.

A benign condition. In the absence of instability or structural deficiency of the cervical spine, CCN appears to be clinically benign. Torg et al (12), in a study of a large group of football players who had cervical spine stenosis and episodes of CCN, found that 109 of 110 athletes had complete neurologic recovery and that no permanent morbidity occurred in the 63 patients who returned to contact sports. (The one case of irreversible neurologic injury was a direct complication of surgery.) Further, a study (12) of MRI images of 25 professional football players who had CCN episodes with significant cervical canal stenosis and cervical spondylosis showed that all patients with actual cord compression from degenerative disks safely returned to contact activities. Thus, developmental or spondylitic stenosis, regardless of the degree of canal narrowing, does not result in irreversible cord injury.

Predicting recurrence. Though patients who have an episode of CCN are not at increased risk of permanent injury when they return to contact sports, they should be advised that they may have recurrent episodes. Thirty-five (56%) of the 63 aforementioned patients who returned to contact activities after a CCN incident had a recurrence. Participation in football and increased stenosis raise the risk of recurrence. MRI measurement of disk-level canal diameter was the best predictor of recurrence risk, followed by the ratio of the spinal canal diameter to the vertebral body diameter (figure 9a: not shown) and by the space available for the cord. Given the technical requirements for making an accurate MRI measurement, the ratio is the method of choice in general practice.

Although Herzog et al (13) have suggested that the ratio is overly sensitive in diagnosing cervical stenosis, it is a reliable, accurate, and accessible method for quantifying the risk of CCN recurrence when used with the probability-of-recurrence graph (figure 9b: not shown). With the ratio and the graph, a physician can counsel patients with CCN regarding their risk of recurrence. For example, a CCN patient with a spinal canal/vertebral body ratio of 0.5 has approximately a 75% risk of a recurrent episode. Because of the low specificity and low positive predictive value, however, the canal/vertebral body ratio should not be used as a screening test for athletes who have not had an episode of CCN.

Several investigators have observed an inverse relationship between increased posttraumatic myelopathy and sagittal diameter of the cervical canal in patients suffering fracture, dislocation, or instability of the cervical spine (14,15). In the series of Torg et al (11), there was no correlation between the severity of the clinical manifestations of CCN and the degree of narrowing. But unlike patients in the other studies, the latter patients did not have loss of cervical spine stability.

Return-to-play recommendations. Though we believe that CCN is a benign entity, all patients should undergo a routine plain-film radiographic and MRI examination. Patients with uncomplicated CCN may be advised that they can return to contact activities without increased risk of permanent neurologic injury. However, since the overall recurrence rate of 56% (12) is related to the degree of cervical canal narrowing, patients can be counseled regarding the risk of recurrence using the following recommendations:

• Asymptomatic patients with a canal/vertebral body ratio of 0.8 or less: no contraindication;
• Patients with a ratio of 0.8 or less who have had one CCN episode: relative contraindication;
• Patients with CCN episodes and degenerative changes and/or intervertebral disk disease: relative contraindication;
• Patients with a CCN episode and MRI indication of cord defect or edema: relative to absolute contraindication; and,
• Patients with a CCN episode, ligamentous instability, neurologic symptoms lasting more than 36 hours, and/or multiple episodes: absolute contraindication.

Spear Tackler's Spine

Spear tackler's spine is a condition that occurs in football players who habitually use the head as the initial point of contact (16). Plain radiographs (figure 10: not shown) of the condition show cervical stenosis, posttraumatic changes, and loss of the normal cervical lordosis. An erect lateral view of the neck in neutral alignment best shows the loss of the normal cervical lordosis. The straightening of the cervical spine is the result of repeated axial loading and microtrauma to the spinal structures and may or may not be reversible. The straightened cervical spine acts like a segmented column (figure 11), predisposing the spine to permanent neurologic injury with further axial loading; thus, the combination of spear tackler's spine and head-first tackling is extremely dangerous. Spear tackler's spine is therefore an absolute contraindication to further participation in contact sports.

In patients whose loss of cervical lordosis is reversible, a return to activity may be considered when the normal lordotic curve returns. Counseling regarding the perils of head-first impact is imperative, as is the teaching of safe tackling techniques.

Fractures

In a patient with or without ligamentous laxity, an acute fracture of either the vertebral body or the posterior elements is an absolute contraindication to participation. However, depending on the type and location of the fracture, healed lesions may or may not preclude further participation (table 1). Consultation with an experienced sports medicine orthopedist should be obtained to assist in deciding whether further participation is prudent.

The axial-load teardrop fracture. This fracture is a variant of the burst fracture and is different from the isolated tear-drop fracture (17). The latter (figure 12a: not shown) is a fracture of the anteroinferior corner of the vertebra and is not usually associated with permanent neurologic sequelae.

In contrast, the axial-load teardrop fracture (figures 12b, 12c, and 12d: not shown) is a three-part, two-plane fracture including a sagittal vertebral body fracture and a fracture of the posterior neural arch. It is caused by severe compression. Although the name focuses attention on the anteroinferior vertebral body fracture, the unstable fracture pattern is actually responsible for encroachment on the spinal cord, which results in the paralysis that frequently accompanies this injury.

Cervical Spine Fusion

A patient who has undergone spine fusion does not necessarily have to avoid contact activities, but recommendations vary according to the individual's signs and symptoms and the level of vertebral fusion:

• No contraindication for patients with a stable, one-level anterior or posterior fusion at C-3 or below, so long as they are neurologically normal, are free of pain, and have a normal range of cervical motion.
• Relative contraindication for patients who have a stable, two- or three-level anterior or posterior fusion, are neurologically normal and asymptomatic, and have full, painless cervical motion. It appears that these patients should only rarely be permitted to return to contact activities, because stresses at the articulations of the vertebrae adjacent to the fusion will probably increase and may lead to degenerative changes.
• Absolute contraindication for those with anterior or posterior fusion of more than three levels.

Spinal Cord Resuscitation

Research over the past 20 years has clearly established the principles of brain resuscitation in the management of closed head injuries. The pathophysiologic and mechanistic phenomena causing morbidity in these head injuries are the same as those causing morbidity in acute spinal cord trauma (18). Specifically, secondary spinal cord injury caused by hypoxia, edema, and aberration of cell membrane potential is largely responsible for neurologic deficits. The methods of spinal cord resuscitation seek to minimize hypoxia, edema, and aberrations of cell membrane potential in an attempt to reverse secondary changes and enhance neurologic recovery. These methods include the following:

• Treatment of any aberrations of neurovascular function, with particular regard to maintaining blood pressure and respiration.
• Prompt reduction of spinal deformity so as to relieve cord deformation.
• Prompt stabilization of the injured segment of the cervical spine.
• Use of intravenous corticosteroids in recommended doses (19). Within 8 hours of injury, methylprednisolone, 30 mg/kg, should be given as a bolus, followed by an infusion of 5.4 mg/kg/hr for 23 hours. In a major trial, 19 patients who received methylprednisolone within 8 hours of injury improved significantly at 6 months compared with those who received a placebo. The steroid may suppress the breakdown of the cell membrane by inhibiting lipid peroxidation and hydrolysis at the injury site. When lipid peroxidation is inhibited, the vasoreactive products of arachidonic acid metabolism decrease and blood flow at the site of injury is improved.
• Use of cerebrogangliosides, such as Sygen (GM-1), in an attempt to facilitate the patient's neurologic recovery.

Individualized Advice

The proposed recommendations for managing cervical spine injuries are based on the best available information. As more data are gathered, however, changes may be necessary. In deciding whether or not an athlete can safely return to contact sports, the athlete's age, experience, ability, position, and level of participation should be considered along with the recommendations.

References

1. Torg JS, Truex R, Quedenfeld TC: The National Football Head and Neck Injury Registry: report and conclusions. JAMA 1979;241(14):1477-1479
2. Torg JS, Vegso JJ, O'Neill J, et al: The epidemiologic, pathologic, biomechanical, and cinematographic analysis of football-induced cervical spine trauma. Am J Sports Med 1990;18(1):50-57
3. Torg JS, Vegso JJ, Sennett B, et al: The National Football Head and Neck Injury Registry: 14 year report on cervical quadriplegia, 1971 through 1984. JAMA 1985;254(24):3439-3443
4. Otis JC, Burstein AH, Torg JS: Mechanisms and pathomechanics of athletic injuries to the cervical spine, in Torg JS (ed): Athletic Injuries to the Head, Neck and Face, ed 2. St Louis, CV Mosby Co, 1991, pp 438-456
5. Torg JS, Reilly PJ: Injuries to the cervical nerve roots and brachial plexus in athletes. Current Opinions in Orthopaedics, 1994;5(2):79-84
6. Levitz CL, Reilly PJ, Torg JS: The pathomechanics of chronic, recurrent cervical nerve root neurapraxia: the chronic burner syndrome. Am J Sports Med 1997;25(1):73-76
7. Albright JP, Moses JM, Feldick HG, et al: Nonfatal cervical spine injuries in interscholastic football. JAMA 1976;236(11):1243-1245
8. White AA, Johnson RM, Panjabi MM, et al: Biomechanical analysis of clinical stability in the cervical spine. Clin Orthop 1975;109:85-95
9. Torg JS, Pavlov H, Genuario SE, et al: Neurapraxia of the cervical spinal cord with transient quadriplegia. J Bone Joint Surg (Am) 1986;68(9):1354-1370
10. Torg JS, Naranja J, Pavlov H, et al: The relationship of developmental narrowing of the cervical spinal canal to reversible and irreversible injury to the cervical spinal cord in football players. J Bone Joint Surg (Am) 1996;78(9):1308-1314
11. Torg JS, Thibault L, Sennett B, et al: The pathomechanics and pathophysiology of cervical spinal cord injury. Clin Orthop 1995;321(Dec):259-269
12. Torg JS, Corcoran TA, Pavlov H, et al: Cervical cord neurapraxia classification, pathomechanics, morbidity and management guidelines. J Neurosurg, to be published
13. Herzog RJ, Wiens JJ, Dillingham MF, et al: Normal cervical spine morphometry and cervical spine stenosis in asymptomatic professional football players: plain film radiography, multiplanar computed tomography, and magnetic resonance imaging. Spine 1990;16(6 suppl):178-186
14. Eismont FJ, Clifford S, Goldberg M, et al: Cervical sagittal spinal canal size in spine injuries. Spine 1984;9(7):663-666
15. Maroon JC, Bailes JE: Athletes with cervical spine injury. Spine 1996;21(19):2294-2299
16. Torg JS, Sennett B, Pavlov H, et al: Spear tackler's spine: an entity precluding participation in tackle football and collision activities that expose the cervical spine to axial energy inputs. Am J Sports Med 1993;21(5):640-649
17. Torg JS, Pavlov H, O'Neill MJ, et al: The axial load teardrop fracture: a biomechanical, clinical and roentgenographic analysis. Am J Sports Med 1991;19(4):355-364
18. Torg JS, Thibault LE: Spinal cord resuscitation, in Current Therapy in Sports Medicine, ed 3. Philadelphia, CV Mosby Co, 1995, pp 66-70
19. Bracken MB, Shepard MS, Collins WF, et al: A randomized controlled trial of methylprednisolone or naloxone with treatment of acute spinal cord injury: results of the second National Acute Spinal Cord Injury Study. N Engl J Med 1990;322(20):1405-1411

For more information on this subject, see Torg JS, Ramsey-Emrhein JA: Management guidelines for participation in collision activities with congenital, developmental, or postinjury lesions involving the cervical spine. Med Sci Sports Exerc 1997;29(7, clinical suppl), to be published.

Dr Torg is a professor of orthopedic surgery at Allegheny University for Health Sciences in Philadelphia; Ms Ramsey-Emrhein is head athletic trainer at Dickinson College in Carlisle, Pennsylvania. Dr Torg is an editorial board member of The Physician and Sportsmedicine. Address correspondence to Joseph S. Torg, MD, Allegheny University Hospitals-Center City, Broad and Vine, Philadelphia, PA 19102-1192; send e-mail to torgmd@aol.com.

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