Snowboarding is associated with a risk of spinal injuries. In those who sustain acute transverse process fractures, concomitant spinal injuries commonly are found. Spondylolysis and spondylolisthesis are typical overuse injuries, which may present as acute or chronic back pain, and snowboarding traditionally has not been considered a high-risk sport. Spondylolytic injuries are more common in the adolescent athlete, especially in activities that include lumbar hyperextension, and account for a large percentage of youth back pain visits in a sports medicine practice. Determining the acuity of spondylolytic injuries may or may not change the management of an affected athlete with pain.
A previously healthy 14-yr-old male snowboarder presented for follow-up after an acute back injury sustained on the slopes during competition 5 d earlier while performing a "turning backside 50/50 gnarly front side 180 out;" a trick that requires significant lumbar hyperextension. He reported losing his balance in the air and landing on the icy slope in a position that drove his left elbow into his lower back. The athlete had immediate pain in his lumbar region and was transported to a nearby hospital emergency room on a backboard. He was examined by an emergency room physician, who noted no neurological deficits, was imaged with a lumbar computed tomography (CT) scan, released home with narcotic pain medication, and instructed to follow up in the Sports Medicine Clinic the following week.
When he presented at our clinic, he described an 8/10 intensity, sharp, shooting, and burning pain located mainly in the central lower back with some lesser pain in the mid back. He stated the pain radiated into his left thigh, worsened with any movement, and was only relieved by the narcotic pain medication. He reported no history of previous back injuries or pain, parasthesias, weakness, or bowel and bladder dysfunction. The athlete had been a locally competitive snowboarder for 2 yr, was in mid season, and had not increased his training. He did not wear a backpack at school or otherwise.
The only family history of back problems was with his father, who had a season-ending back injury during high school football, and many years later, he had magnetic resonance imaging (MRI) obtained for worsening chronic back pain, demonstrating a bilateral L4 spondylolysis and grade 1 spondylolisthesis. There was no family history of systemic or familial joint problems.
Upon examination at our clinic, the athlete had an antalgic gait, appeared moderately uncomfortable, and had significant splinting and guarding in the left paraspinous muscles. He was tender to palpation over the left L2 and L3 paraspinous musculature, but had much more tenderness with palpation of the L5 vertebral spinous process in the midline. Active spine range of motion was severely limited secondary to pain and he was unable to attempt one leg hyperextension testing. He had a normal motor, sensory, vascular, and reflex examination of his lower extremities.
Plain radiographs taken at our clinic showed the patient had a grade 1 spondylolisthesis. The lumbar CT scan obtained in the emergency room demonstrated acute nondisplaced fractures through the left L2 and L3 transverse processes and an L5 bilateral spondylolysis with grade 1 spondylolisthesis (5 mm) of L5 on S1 (Fig. 1). Wide fracture margins and sclerosis were noted, which can be indicative of either a subacute or chronic lesion.
Working Diagnosis and Care Plan
The patient was diagnosed with acute left L2 and L3 transverse process fractures, grade one spondylolisthesis of L5 on S1, and bilateral L5 spondylolysis of undetermined acuity. Noting the wide fracture margins of the spondylolysis along with the appearance of mild sclerosis and cortication of bone, the acuity of the lesions was questioned. The differential diagnosis included acute spondylolysis, acute on chronic spondylolysis, acute spondylolisthesis, and if chronic, injury to the fibrous connection of the spondylolysis. Based on the history of no previous back pain, the mechanism of injury, and most importantly, the physical exam eliciting severe L5 pain with palpation, the patient was treated as if he had an acute spondylolytic injury. A consulting spine surgeon recommended a thoracolumbosacral orthotic (TLSO) brace extending to the mid thoracic area (Fig. 2), which was fitted on the following day, to be worn 23 of 24 h daily for pain control and to potentially facilitate any bony healing at the injury sites. The patient was continued on the same pain medication and asked to return to the clinic in 3 wk for reevaluation.
At his 3-wk follow-up visit, the patient had a significant decrease in his low lumbar pain, and his lower extremity neurological exam remained normal. He noted a sense of instability whenever the brace was removed, with an associated increase in lower back pain. After 10 d, he no longer required narcotics to sleep or for activity. His lumbar radiographs at that time demonstrated a stable grade 1 spondylolisthesis.
At the 6-wk visit, he was pain free with activities of daily living while wearing the brace. We decided to continue bracing, but to remove it for his exercise program, which focused on hamstring flexibility and hip flexor strength. At 9 wk post injury, he was allowed to remove the brace for sedentary activities and was advanced to transversus abdominus and hip ad/abduction exercises. At 12 wk post injury, the snowboarding season had ended, he was pain free with lumbar hyperextension, and was advanced to a home exercise program that allowed sport-specific activities. He did not participate in other sports, but was planning on resuming snowboarding the next season. He was instructed to return in 1 yr for follow-up radiographs to assess the spondylolisthesis for any slip progression.
This young athlete had two adjacent and acute transverse process factures with an associated spondylolytic lesion. Most spondylolytic lesions in athletes are felt to be either incidental findings or are caused by repetitive stress forces from hyperextension activities. The CT scan demonstrates bilateral spondylolysis with some features of a subacute lesion. Clinically, our athlete had significantly more pain at the L5 vertebrae than at the L2 or L3 vertebral transverse process fracture sites. There were no previous radiographs to determine the acuity of the spondylolysis or the spondylolisthesis. This case presents the clinical dilemma of multiple acute transverse process fractures associated with significant and more severe pain at the site of bilateral pars fractures with grade 1 spondylolisthesis of undetermined acuity.
Sport-Specific Injury Pattern
Spinal injuries are among the most potentially devastating in recreational sports. The incidence of spinal injuries in snowboarding is 0.04 per 1000 snowboarder-days (1). The thoracolumbar spine is a common site of snowboarding injury, fourfold greater than alpine skiing, with jumping heights greater than 2 m being the greatest risk factor (1). Yamakawa noted a significantly higher incidence of transverse process fractures in snowboarders, with 69% of all fractures occurring in the lumbar spine (2). Furthermore, transverse process fractures commonly are associated with other injuries - 88% in one study (3).
Definition, Etiology, and Incidence
Spondylolysis, a defect of the pars interarticularis most commonly found at L5, usually is considered a stress fracture caused by repetitive hyperextension and microtrauma (4,5). While the fetal incidence has been shown to be zero, the prevalence is 4.4% by age 6 (6) and up to 8% in the adult population (7) with a 2:1 male: female ratio (6). It is more common in the young athletic population (8), and as frequent as 47% in an adolescent population presenting with back pain (9,10).
Spondylolisthesis is the anterior translation of one vertebral segment upon its subjacent neighbor that requires bilateral fractures of the pars or childhood slip of the epiphyseal plates (6). Acute fracture of the pars interarticularis with associated spondylolisthesis has been reported (11,12), and often is associated with other injuries, such as multiple transverse process fractures, because of the high force loads required to produce such an injury.
The initial imaging evaluation of low back pain should begin with plain radiographs, although only one third of x-rays will demonstrate the classic appearance of the "Scotty dog" defect with the traditional oblique views (10). Single photon emission computed tomography (SPECT) scanning has a much higher sensitivity and may be the study of choice if plain films are negative (10). Patients with positive SPECT scans and unilateral defects are more likely to achieve bony healing, but many patients will form a pseudoarthrosis with fibrous scar tissue at the fracture site (5,10,13,14). A low uptake (cold) SPECT bone scan with obvious spondylolysis is felt to indicate long-standing fibrous nonunion and poor healing potential (7). CT, often used in trauma, provides greater bony detail, and with reverse-angle axial oblique images, some fractures not seen on bone scintigraphy may be seen (14). MRI is generally reserved for patients with neurologic or refractory symptoms, although bony edema may provide evidence for an acute process and can also evaluate the soft tissue for injury (10,13).
Based mainly on the clinical exam, this patient was diagnosed with an acute spondylolytic injury - most likely an acute spondylolisthesis complicating a previously asymptomatic spondylolysis - and associated transverse process fractures. The CT scan demonstrated wide fracture margins, mild sclerosis, and bone cortication (Fig. 1), which can be seen in subacute and chronic injuries (15). MRI would have been the next best study in this case and may have given some clues to the acuity of the spondylolytic lesions, but given the location and amount of pain this patient was experiencing, the study would not have altered the treatment plan.
Transverse process fractures are considered minor fractures and do not affect the stability of the spine. Treatment consists of protecting the area from repeat trauma; generally, no immobilization is required for these fractures, and bracing can add to the discomfort (16).
There remains controversy regarding the goals and methods of treatment for spondylolysis, regardless of its etiology. Treatment has been studied using different diagnostic standards, interventions, and outcome measures (17). Authors have proposed outcome goals such as symptomatic relief, bony union, or prevention of long-term sequelae - for example progression of spondylolisthesis or disability that limits return to sport, job choices, or ability to work (5,6). For the athlete, the short-term goals are relief of pain and return to sport. While some authors recommend lumbosacral bracing for 3 to 6 months (19,20), others recommend bracing only for pain relief, as bony union is not needed for clinical healing or return to play (7,16,19) and because most spondylolytic defects become asymptomatic despite nonunion of the pars defect (5,15). Bracing becomes even more controversial when bilateral fractures are present because the healing potential of these lesions is low (5,6,7,19). Bracing may only be indicated if the patient has significant pain after 2 to 4 wk of avoiding lumbar hyperextension (21), which will limit activities despite allowing more intervertebral motion (22). This rational is supported by a recent study of adolescent soccer players, in which bracing added no benefits as long as the players were held out of sport for 12 wk (23). Most of the studies are with patients with presumed chronic stress fractures, and there are minimal data on potential acute spondylolytic injuries such as the one we encountered in this case. Because the athlete was in significant pain and was felt to have an acute spondylolytic injury in addition to the transverse process fractures, bracing was chosen for treatment.
When an athlete can return to play following acute pain from a spondylolytic lesion is not well studied. Most authors agree that the athlete must be pain free with lumbar hyperextension and in sport-specific activities (22). A review from 2002 recommended 5 to 7 months for a lesion with potential healing or 2 to 5 months for the chronic appearing defect (21). In the study of soccer players, 3 months of sport cessation was associated with better outcomes than a more rapid return (23). Again, these are in athletes with presumed chronic stress injuries, but pain-free sport-specific activities should be demonstrated before return to competition, as with any injury.
If an athlete has continued pain despite conservative management, use of a magnetic field bone growth stimulator and bracing have been reported in two cases to heal bilateral pars fractures after 12 to 14 months of bracing alone (24). While it is appealing in theory to have bony healing for every patient, the results of these two cases have not been reproduced in the literature, nor has bony healing yet to be shown to affect long-term outcomes (25).
In a 45-yr prospective study looking at the natural history of spondylolysis and spondylolisthesis, the prognosis for a 6-yr-old child with a defect in the pars, even bilateral, was the same as the general population with regards to pain and disability (6). The presence of spondylolisthesis did not correlate with previous lumbar back surgeries, and the degree of degenerative change found at follow-up did not correlate with reported pain scores. In a 9-yr follow-up of athletes with normal plain radiographs, positive SPECT scans, and CT scans consistent with spondylolysis, none of the bilateral lesions healed, and all were associated with more arthritic changes on imaging (5). However, 91% of the study participants had good to excellent functional outcomes up to 11 yr later, and all were still active in a variety of sports (5).
Lumbar spine injuries and transverse process fractures are common in the sport of snowboarding. With acute transverse process fractures, imaging with CT may be warranted because they rarely are isolated injuries. While the treatment of transverse process fractures only requires padding, the treatment of spondylolysis and spondylolisthesis remains controversial despite similar short-term functional outcomes with various methods, including thoracolumbosacral bracing. Currently, long-term studies do not support achieving bony union as the final treatment endpoint, as it does not change or affect long-term outcomes. Given this patient's clinical exam, the acuity of his spondylolytic injury likely would not have changed our management. MRI scanning may have provided more information regarding the acuity of the injury and possibly the potential for bony union, but based upon the current literature, it would not have changed any short- or long-term treatment decisions or clinical outcomes. More study needs to be done regarding the potential long-term benefit of bony union, the use of bracing - if and when - and the use of bone growth stimulators. As James M. Hunter famously once said, we must "treat the patient, not the x-ray."
The authors thank Ed McFarland, M.D., FACSM, Mark A. Harrast, M.D., FACSM, for manuscript review; and Joseph Baraga, M.D., Ph.D., Ronald Pobiel, M.D., and Deanna Nelson, ATC, Ph.D., for their assistance with this case.
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