Axial Low Back Pain in Elite Athletes





Back pain in sport is a common complaint and seen by athletes, trainers, and treating physicians. Although there are a multitude of pain generators, mechanical sources are most common. Certain sports can lead to increased mechanical and axial loading, such as competitive weightlifting and football. Common mechanical causes of pain include disk herniation and spondylolysis. Patients typically respond to early identification and conservative treatment. In others, surgical intervention is required to provide stability and prevent long-term sequelae.


Key points








  • Lower back pain is prevalent in the general population and in athletes.



  • Most patients respond well to conservative treatment.



  • A high clinical suspicion and prompt management can prevent worsening or permanent sequelae.




Introduction


Lower back pain is a common complaint in the general population. An estimated 15% to 20% experience an episode of back pain in a single year. Over the course of a lifetime, 50% to 80% of individuals experience at least 1 episode. Some estimates are higher, estimating the prevalence up to 85% to 95%.


Within athletes, back pain is an already complex and vague entity confounded by the specific sport, etiology (traumatic or congenital spine anatomy), and the level of competition of the athlete. Athletic activity in general subjects the body and specifically the spine to extreme physical demand, inducing or exacerbating degenerative changes.


The entirety of the spine is at risk, with catastrophic spinal injuries possible from trauma in higher risk sports such as football, ice hockey, diving, and snowboarding. Axial compression of the spinal column proximally (cervical spine) may lead to fracture and even quadriplegia. In the lumbar spine, sports-associated axial loading forces tend to lead to degenerative changes or disk herniations. There is a direct correlation with increasing lumbar flexion and compressive loads across the intervertebral disk.


Low back pain is more common in athletes of certain sports compared with others. Herniated lumbar disks are most common in football players and weight lifters, degenerative disks and spondylolysis most common in gymnasts, and traumatic lumbar spine injuries most common in wrestlers and hockey players. Sacral fractures are thought to occur more frequently in high-level running sports. In one study of 4790 athletes, 80% of injuries occurred in practice, 6% in competition and 14% in preseason conditioning.


The workup and evaluation of back pain in an athlete requires a careful history, complete neuromuscular examination, and corresponding imaging. The source of the pain can be difficult to identify, secondary to paraspinal musculature, degeneration or herniation of the intervertebral disks, or due to instability from spondylolysis with associated spondylolisthesis. It may also be due to repetitive microtrauma and overuse, leading to acute or chronic injuries such as spondylolysis.


It is often difficult to achieve compliance with nonoperative treatment modalities in the athlete. Although most patients respond clinically positively to cessation of sports, rest, and physical therapy, the competitive nature of athletics often leads to poor compliance. This can result in a deterioration of the condition and ultimately the need for surgical intervention.


The exact source of pain generators may or may not be found. A high index of suspicion and workup is warranted to rule out fractures or soft tissue injuries. Careful history, complete neuromuscular physical examination, and appropriate imaging should be performed.


History and physical examination of the athlete


As with all patients who experience spinal pathologies, a detailed history and physical examination are critical in achieving an accurate diagnosis as well as ruling out spine surgical emergencies. Specific questions should include symptom onset, duration, frequency, severity, location of pain, a history of inciting trauma or antecedent injury, and if there is a history of similar pain or symptoms. Red flags or warning signs of night pain, fever, or weight loss should warrant immediate concern for non-musculocutaneous etiologies.


Visual inspection for skin lesions or deformity should be performed, followed by palpation and percussion along the midline and paraspinal musculature. Additional palpation should be performed for possible masses or step off in the posterior element. Other clinical key points to assess for are the presence of pelvic obliquity and leg length discrepancy, gait abnormalities, as well as any deficits or pain in the active range of motion of the lumbar spine. Finally, a complete neurologic examination is critical to assess for motor and sensory function and reflexes.


Imaging


Plain film radiographs are the first-line diagnostic modality in the evaluation of the athlete with axial low back pain. It is a critical step in the clinical process and should not be skipped in favor of more advanced modalities. Imaging is warranted in the setting of a localized pain or deformity and can both rule out and rule in diagnoses such as spondylolysis, spondylolisthesis, transverse process avulsion fractures, and compression fractures.


Advance imaging modalities are useful in the setting of inconclusive or subtle findings found on plain film. Standard choices are computed tomography (CT) or MRI, with indications and contradictions for both. These are expanded on in further sections. Single photon emission computed tomography may be useful in patients suspected of having spondylolysis.


Differential


Back pain is a vague symptom, with many descriptors and qualities, but not a true diagnosis. There are many possible etiologies for back pain in the athlete. The most common causes are muscle/ligament strain, degenerative disk disease, disk herniation, isthmic spondylolysis, and isthmic spondylolisthesis ( Box 1 ).



Box 1

Differential diagnoses of low back pain





  • Musculocutaneous in origin




    • Muscle strain/sprain



    • Muscle contusion



    • Degenerative disk disease



    • Isthmic spondylolysis



    • Isthmic spondylolisthesis



    • Disk herniation



    • Facet stress fracture



    • Sacral stress fracture



    • Transverse process avulsion fracture




  • Other




    • Diskitis



    • Osteomyelitis



    • Neoplasm





Lumbar Strain


Muscular injury typically occurs in the musculotendinous junction, although injury within the muscle belly or insertion can occur as well. Injury occurs to the tissue and muscle fibers without full disruption, and leads to inciting inflammation and pain. Lumbar strains can occur acutely within 48 hours of injury and are associated with muscular spasms. Recurrent muscular strains are characterized by periods without symptoms. Chronic muscle strains are injuries of a greater duration with long-term muscle injury. This category of injury is typically the most found in athletes.


Radiographic workups yield negative results, and on physical examination, findings are nonspecific. The pain may be localized focally to the muscle, or present as a diffuse tightness or dull pain. The diagnosis of lumbar strain is typically of exclusion.


Treatment is nonsurgical, with excellent results and return to play. Rest, icing, and medications are the mainstay of treatment. After a brief period of rest, nonsteroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, and physical therapy should be initiated. The athlete should be pain free with normal function before return to sport.


Degenerative Disk Disease


In degenerative disk disease, there are progressive changes that occur with subsequent disk space narrowing, loss of disk hydration, and altered biomechanics and malalignment. This ultimately leads to abnormal facet loading and eventually facet arthropathy. There has been strong support in the literature for a genetic predisposition for lumbar degenerative changes. It has been suggested in the literature that patients with a first-degree or third-degree relative with degenerative disk disease have a markedly elevated risk. In a study comparing 308 collegiate athletes against a control group of 71 nonathlete university students, there was a considerably higher incidence of early lumbar degenerative changes found in the athletic group.


The history and physical examination of patients with degenerative disk disease can also be difficult to elucidate initially. Commonly, a deep, aching lower back pain is described. This pain is worsened by flexion and compressive loads. Relief is achieved with rest and laying in the supine position.


First-line imaging consists of lumbar plain film radiographs to evaluate for abnormal findings including disk space narrowing, subchondral cysts, facet degeneration, and osteophytic changes. Flexion and extension radiographs are helpful in assessing for mobility and stability. CT and MRI provide higher sensitivity and specificity for detecting disk pathology. Hallmark findings include loss of signal intensity on T2-weighted images, annular tears, and associated bone marrow/vertebral end plate changes. It is interesting and important to note that imaging findings do not necessarily correlate with clinical findings: asymptomatic patients may have findings on imaging, or vice versa. , ,


Lumbar Disk Herniation


Interverbal disks serve an important role in distributing loads and allowing for motion in multiple planes. When a herniation occurs, the inner nucleus pulposus ruptures through the outer annulus, and may cause compression on the nerve roots. Herniations can be classified based on their location ( Fig. 1 ). Athletes experience high mechanical stresses during competition and training, and these can include torsional or axial loading of the spine, which may predispose athletes to lumbar disc herniation (LDH). Due to the avascularity of the intervertebral disk, damage is accumulative with limited repair. As noted previously, certain sports, such as weightlifting and football, are at greater risk than others. Sports with repetitive maneuvers can further increase this risk.


Jun 13, 2021 | Posted by in SPORT MEDICINE | Comments Off on Axial Low Back Pain in Elite Athletes
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