Participation in Contact or Collision Sports in Athletes With Epilepsy, Genetic Risk Factors, Structural Brain Lesions, or History of Craniotomy

Vincent J. Miele, M.D.; Julian E. Bailes, M.D.; Neil A. Martin, M.D.

Disclosures

Neurosurg Focus. 2006;21(4) 

In This Article

Chiari Malformation Type I

The CM-I is a congenital disorder with an unknown incidence characterized by the caudal herniation of cerebellar tonsils through the foramen magnum. This is an increasingly recognized finding on MR imaging, with a mean age at onset of symptoms and diagnosis of 25 ± 15 years, which overlaps with the most common years of participation in contact and/or collision sports. The variable clinical symptoms result from brainstem compression by the herniating tonsils and from disorders of CSF circulation.[52] Classic symptoms are severe throbbing headache and neck pain, starting shortly after coughing, sneezing, straining, changing posture, or physical exertion. Because symptoms may be provoked by increased intracranial pressure,[49] it has been questioned whether the presence of a CM-I may alter the normal CSF capacity for buffering the brain in instances of high-velocity impacts.[6] Although this is of no apparent consequence during normal activities, this abnormality may prevent the normal buoyancy of the CSF from safely protecting the brain from the strong forces that can be generated during impact in contact sports.

Numerous football players at the high school and college levels who sustained concussions were later found to have CM-Is as their only abnormality on radiographic evaluations.[5] Whether these findings are incidental or the CM-I was a contributing factor to their injury is a subject of debate. Also of concern is the rare fatality associated with the condition; several cases of sudden cardiorespiratory arrest in children with no prior neurological abnormalities have been reported.[50,77] Cardiac arrest has also been described following a brisk head movement in an adult with a CM-I,[1] as have been deaths following minor head trauma in two adults (it is likely that these fatalities were the result of respiratory arrest).[82] This could be the result of medullary compression from the cerebellar tonsillar herniation, which may have depressed the function of the respiratory center, producing hypoxia.[83] "Drop attacks," one of the features of basilar migraine, are also one of the uncommon manifestations of CM-I, having been reported in 2 to 3% of patients in recent series.[27,59,74] These attacks also seem to be related to compression of the medulla caused by temporarily increased tonsillar herniation.

At present, a CM-I per se seems to be more of a relative than an absolute contraindication to further participation in contact sports in asymptomatic patients. In those in whom this abnormality was discovered during a diagnostic evaluation for concussion, we have generally reacted conservatively and recommended against a return to contact sports. Refraining from contact sports has been recommended in patients who harbor CM-I with associated syringomyelia, obliteration of the subarachnoid space, or indentation of the anterior medulla.[11] Additionally, the presence of a CM-I that is symptomatic should contra indicate participation in contact or collision sports.

The septum pellucidum consists of two leaves of glial tissue that are usually fused or contiguous in adults. If they remain separated, then the anterior closed space between them is known as a cavum septum pellucidum. The actual incidence of this entity in the general population at any time after the neonatal period has a wide reported incidence range (3–60%).[22,51,69]

Although its presence is a common and usually incidental finding on neuroimaging or neuropathological studies, an association of the cavum septum pellucidum with boxers was first noted incidentally in 1962.[72] The condition has been repeatedly associated with chronic TBI in boxing, on the basis of neuroimaging or postmortem studies. It is likely that a cavum septum pellucidum in boxers is acquired rather than being congenital and results from rotational injuries that lead to tearing and separation of the septum pellucidum.[51] It has also been implicated in other types of brain trauma, such as those sustained in fatal road traffic accidents.[61]

Importantly, the cavum septum pellucidum abnormality discussed in neuropathological studies as pointing to dementia pugilistica is fenestrated as well as being associated with forniceal abnormalities. A cavum septum pellucidum with intact walls is not a diagnostic finding of this condition.[51] Additionally, there is no evidence that this entity necessarily correlates with neuropsychological or clinical abnormalities. The presence of an isolated cavum septum pellucidum is unlikely to be of clinical importance and should not preclude an athlete from participation in contact or collision sports. It has been reported that the morphological features of this entity may vary between examinations.[84] The development or serial enlargement of a cavum septum pellucidum could be evidence of the early development of chronic brain damage or dementia pugilistica, particularly if associated with other evidence of neurological deficit.

A significant improvement in the prognosis for children in whom shunts have been placed to treat hydrocephalus has been made during the past 20 years, and a considerable percentage of this population attains high levels of neurological functioning and is able to participate in organized sports.[9,10,16] The estimated prevalence of VP shunts is 125,000 in the US.[8] The medical literature contains few articles that specifically address the issue of sports-related shunt complications.[7] Additionally, a recent review of the legal literature was performed and failed to produce any cases of sports-related shunt complications.

There are several reasons why this population is thought to be at a higher risk for neurological sequelae during participation in sports. Some of these patients have persistent ventriculomegaly despite shunt placement. These athletes may be at risk for cortical collapse over their enlarged ventricles, with secondary tearing of bridging veins and development of SDHs.[7] Patients who have had long-standing hydrocephalus sometimes have a thinner cranium. This could increase the risk to the participant for brain injury from impacts to the head. The physiological reserve of the central nervous system to respond to injury may be significantly reduced in this population due to the original insult that caused the hydrocephalus. The CSF acts in part as a shock absorber for the brain. Patients who have undergone shunt placement for hydrocephalus have a change in the dynamics of the CSF flow that could have a negative impact on this buffering effect.

A survey of the Joint Section on Pediatric Neurosurgery of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons was recently published.[7] This survey revealed a very low incidence of sports-related problems with VP shunts; the incidence of sports-related shunt complications was significantly less than 1%. None of these instances were reported to have caused a neurological morbidity or a fatality. The most commonly described issues were shunt fractures and shunt dysfunction occurring close in time to participation in an active sport. The catheters of the currently used systems can become calcified along their tracks over time and may become adherent to adjacent tissue. This may in crease the risk of fracture or disconnection of the catheter during participation in sports. Dysfunction of the shunt caused by a sports-related fall directly onto the shunt valve has been reported. The sporting events most frequently implicated by providers were wrestling and soccer. Three providers specifically indicated that the observed adverse event could be attributed to supervised wrestling. All such events involved catheter disconnections or fractures. Accumulation of a clot or other subdural fluid collection was reported by four providers. Three of these involved subacute subdural fluid accumulations in patients with enlarged ventricles, and one acute clot was reported that occurred in an athlete with normal-sized ventricles who directly headed a fast-traveling soccer ball. Football, turning cartwheels, rapid somersaulting, and sledding or tobogganing were also linked to adverse effects. Overall, this report established that the incidence of observed problems attributable to sport participation in shunt-treated children seems very low.

Currently, there are no guidelines for allowable activities or contact sport restrictions in this population. The majority (89%) of surveyed neurosurgeons do not restrict participation in noncontact sports, and one third of responding neurosurgeons do not restrict participation in contact sports. An other third of responding neurosurgeons prohibit or strongly advise against participation in all contact sports. Football was the most commonly prohibited sport, yet data from this survey did not implicate football-related problems in children treated with shunts. This could be the result of a low incidence of football participation in these children or of improved protective equipment. Boxing and wrestling were also specifically prohibited.

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