THEMATIC ISSUE A Review of Spine Injuries and Return to Play Derrick Eddy, MD,* J. Congeni, MD,*‡ and K. Loud, MD, CM, MSc*†‡ Objective: To review the literature for evidence that pertains to return to play and spine injuries, including cervical spinal stenosis, congenital and developmental abnormalities of the cervical spine, sting- ers, herniated nucleus pulposus, and spondylolysis/spondylolisthesis. Data Sources: Electronic databases, Pubmed (1966–2005) and Sport Discus (1975–2005), were searched for pertinent literature. Also, additional articles were reviewed from bibliographies. Data Synthesis/Methods: Summation of literature is given. No formal statistical analysis is presented. Results: Even though the problems addressed in this paper can be serious, the literature is lacking evidence for guidance in return to play. The majority of the literature presented is expert opinion. Conclusions: Cervical spinal stenosis continues to be controversial, with different experts giving different definitions and return to play recommendations. Authors discuss functional cervical spinal stenosis seen on MRI and how this can lead to permanent sequelae. In regard to stingers, herniated nucleus pulposus, and spondylolysis/spondy- lolisthesis, there are differing opinions on evaluation and treatment. These conditions have less disagreement with regard to return to play. Most experts agree that with these problems or any other problem in sports medicine, an athlete needs to be symptom-free and have full active range of motion with near to full strength, even though there is a lack of research evidence in the literature. Key Words: spine injuries, athletic injuries, cervical spine (Clin J Sport Med 2005;15:453–458) S pine injuries are a significant concern in the athletic popu- lation. The majority of soft tissue injuries are probably not reported, making it difficult to estimate accurately the total number of spine injuries. 1 The more severe spinal injuries are fortunately less common, but bring concern to physicians, certified athletic trainers, parents, and athletes. They also pro- duce controversy because the literature is lacking in randomized control trials (RCTs) examining sport-related spine injuries (Table 1). We are left most often with expert opinion. With decisions relating to return to play, most authors would agree that the participant must be symptom-free, have full active range of motion, and have near to full strength. However, each situation has specific variables. This paper describes a more detailed approach to traumatic spinal cord injury, spinal stenosis, burners, lumbar herniated nucleus pulposus, and spondylolysis. TRAUMATIC SPINAL CORD INJURY One of the most feared risks of athletic participation is spinal cord injury (SCI). Although SCI may seem rare, there are 11,000 cases annually in the United States, with 9% relating to sports, making them the 4th most common cause of SCI. 2 Regardless of their incidence, SCIs have great impact because they are usually life-changing injuries with calamitous results. A total of 116 deaths due to cervical spine injuries were reported in all levels of American football between 1945 and 1994. 3 There has been a decrease in SCI rates with 1976 rule changes, such as the elimination of spear tackling as a legal maneuver. 4 For example, there were 34 cases of tetraplegia in 1976, and only 5 cases in 1984. 5 Also, 42% of fatalities were due to cervical injury in the decade 1965 to 1974. The frequency dropped to 14% and 5% in the next 2 decades. 3 The challenge remains: are there other ways to prevent such catastrophic injuries from occurring? The focus of this paper is to look at the literature to help guide decisions relating to return to sport after a noncatastrophic injury. CERVICAL SPINAL STENOSIS Cervical spinal stenosis is a narrowing of the spinal canal, which can be acquired or congenital. Acquired cervical spinal stenosis is caused by enlargement of facet joints, liga- ments, or encroachment of the disc. Congenital cervical spinal stenosis involves athletes who are born with a smaller diameter canal compared with the general population. Symptoms in- clude weakness and paresthesias and rarely involve neck pain. However, because we rely on radiologic studies to diagnose spinal stenosis, there is debate about the true definition and subsequent difficulty in estimating its prevalence. Lateral c-spine radiographs were first used to evaluate spinal stenosis. On radiograph, one had to have a spinal canal less than 13 mm from the levels of C3-C7 for the diagnosis. 6 This technique subsequently proved to be unreliable due to magnification error. Torg and Pavlov introduced a ratio to account for the magnification error in the late 1980s. The Torg- Pavlov ratio is the diameter of the cervical canal divided by the width of the cervical vertebra. Any measurement less than 0.8 was considered canal stenosis with normal being 1.0. Herzog et al 7 found that many athletes have a larger than normal vertebral body width, which would decrease the ratio and cause the measurement to be misleading. Blackley et al 8 also Accepted August 2005. From *Sports Medicine and †Adolescent Medicine, Akron Children’s Hospital, Akron, OH; and ‡Pediatrics, NEOUCOM, Akron, OH. Reprints: Eddy Derrick, MD, 388 S. Main St., Suite 207, Akron, OH 44311 (e-mail: w81ftr76@yahoo.com). Copyright Ó 2005 by Lippincott Williams & Wilkins Clin J Sport Med  Volume 15, Number 6, November 2005 453