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Bony Healing in a Patient with Bilateral L5 Spondylolysis

Zimmerman, Jerrad MD; Simons, Stephen M. MD

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Current Sports Medicine Reports: February 2005 - Volume 4 - Issue 1 - p 35-37
doi: 10.1097/01.CSMR.0000306069.59767.43
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Spondylolysis in young active individuals is a common diagnosis in sports medicine. Adolescent athletes complaining of persistent low back pain should be thoroughly evaluated. Unlike adults, adolescent athletes with back pain are more likely to have serious underlying conditions associated with their back pain. The most common cause of persistent low back pain in an active adolescent is spondylolysis, but the differential diagnosis includes spondylolisthesis, tumor, herniated disk, muscle strain, and scoliosis, to name a few.

The treatment protocol for spondylolysis varies in geographic regions as a result of limited outcome data. Published reports unfortunately indicate minimal chance of bony healing of bilateral pars interarticularis stress fractures at long-term follow-up.

Case Report

A 14-year-old healthy male baseball pitcher presented with a 1-month history of right-sided low back pain. The pain started after he was shoveling rock for a neighbor. Prior to the injury he was participating in his high school baseball off-season conditioning program. The pain was localized to the L5 region with no radiating neurologic symptoms. Low back extension, running, jumping, and squatting all worsened his symptoms. Nonsteroidal anti-inflammatory medications were ineffective. Symptoms improved with rest. He reported no recent weight change, fevers, or night sweats and had no history of any chronic medical conditions.

On initial examination his height was 68.5 inches, weight 152 pounds, blood pressure 110/68, and heart rate 66 beats/min. He appeared approximately Tanner stage 4. He had normal range of motion of the lumbar spine in flexion and extension without pain. Single-limb, standing extension or stork testing was painful when leaning to the left. He had no tenderness to palpation over the spinous processes or paraspinous musculature. Straight-leg raise was negative bilaterally. Patellar and Achilles reflexes were symmetric. Light touch sensation was normal. The radiographs of the lumbosacral spine, including oblique views, at the initial visit were normal.

A single photon emission computed tomography (SPECT) bone scan of the lumbosacral spine completed 2 days after the initial visit revealed bilateral increased radiotracer uptake to the posterior elements of L5. A fine-slice CT scan of the lumbar spine showed bilateral pars defects with slight marginal sclerosis. The athlete and parent were appraised of the controversial treatment options. They elected to proceed with a Boston overlap brace to be worn 23 hours per day. The patient avoided all aggravating activities until pain free while wearing the brace. He was referred to physical therapy for exercises to increase truncal strength and hamstring flexibility.

The patient became pain free within 2 weeks of rest and brace treatment. Two months later he started light weight lifting, gradually progressing to the spring baseball conditioning program. All activities were performed without pain. A repeat CT of the lumbar spine at 3 months revealed evidence of sclerosis with near-complete healing of the bilateral pars interarticularis defects. A small fracture line was still evident. There was no evidence of spondylolisthesis. He was released without restriction to baseball participation while wearing a trimmed antilordotic brace.

The patient completed a successful baseball season without pain. A third CT scan 6 months following presentation showed continued improvement to the bony healing with only faint fracture lines seen on the axial images (Fig 1). The patient was instructed to wean from the Boston brace, maintain core strengthening, hamstring flexibility, and return to clinic in 1 year or sooner if the pain returned. He has not returned to clinic at this time.

Figure 1
Figure 1:
A, Computed tomography (CT) scan of bilateral par interarticularis fracture at time of diagnosis. B, CT of bilateral pars interarticularis fracture at 3 months from diagnosis. C, CT of left pars interarticularis fracture at 6 months from diagnosis. D, CT of right pars interarticularis fracture at 6 months.


Spondylolysis is a commonly recognized disorder. It occurs in approximately 6% of the adult population and 11% to 83% of the athletic population, depending on the subclass identified. The highest rates occur in divers (83%), gymnasts (38%), wrestlers (33%), and weight lifters (45%). Many other risk factors have been identified for spondylolysis. First-degree relatives of patients with a history of spondylolysis have a 20% to 30% chance of having a spondylolysis. Spondylolysis is more common in males than females. It is also more prevalent in patients with spina bifida occulta. Spondylolysis has never been found in a neonate or never-ambulatory patient [1,2].

Spondylolysis usually presents as low back pain in an active adolescent. The pain usually begins after intense training or after an abrupt increase in activity. The patient will usually not complain of any radicular pain. The pain will be aggravated by hyperextension of the lumbar spine. The stork test for spondylolysis may reproduce the pain. The stork test is performed by having the patient stand on one leg and rotate the spine in the same direction while extending the back. The patient will occasionally complain of pain with palpation of the lumbar spine. Hamstring tightness and hyperlordosis are associated with spondylolysis [1].

The bony healing rate of spondylolysis was most recently evaluated by Miller et al. [3]. They contacted 32 subjects 7 to 11 years following diagnosis of single or bilateral spondylolysis revealed by bone scan but not appreciated by plain films. Based on a low back outcome scale 91% had a good to excellent outcome. CT scans were voluntarily obtained on 11 individuals 7 to 11 years after initial diagnosis. Seven of the individuals receiving follow-up CT scans were initially diagnosed with bilateral spondylolysis and all of their follow up CT scans showed nonunion at the initial fracture site. The four individuals CT scanned 7 to 11 years after unilateral spondylolysis had complete bony healing. A similar study by Sys et al. [4] reported only five of 17 bilateral spondylolysis injuries achieved bony healing.

Delayed presentation or diagnosis of spondylolysis may affect healing rates. It is postulated that lesions found incidentally on CT scan, but not seen on bone scan are less likely to achieve bony healing. It is also reported that spondylolysis found within the first month of symptoms are more likely to form a bony union with conservative bracing therapy than those lesions found after longer than 1 month of symptoms [1].

Treatment of spondylolysis varies from clinician to clinician and from region to region. Some physicians brace all spondylolysis and others brace none. Bracing consists of a hard plastic brace surrounding the lower thorax that limits flexion and extension of the lumbar spine. A commonly used brace is the Boston overlap brace. Bracing duration varies from 4 to 6 weeks to 4 to 6 months or longer after diagnosis. Length of time to return to noncontact activities, contact activities, and collision activities varies tremendously [1,5]. McTimoney and Micheli [1] recommend the following management strategy for spondylolysis. During the initial visit for a patient with suspected spondylolysis PA, lateral and oblique radiographs should be obtained. These should be followed by a SPECT bone scan. If the etiology of the back pain is still not completely clear a CT or MRI of the lumbar spine should be obtained. Once the diagnosis of spondylolysis is made the patient should wear a Boston overlap brace with 0° of lordosis for 23 hours per day for 1 month. Abdominal core strengthening and hamstring stretching exercises can begin once the patient is pain free in the brace. The brace can be trimmed at 1 month for sport-specific activities if the patient is pain free. The patient is not allowed to participate in sporting activities that require back hyperextension. At 3 months from diagnosis a CT scan of the lumbar spine should be obtained to assess bony healing. If bony healing has taken place the patient can be slowly weaned from the brace. If healing has not occurred the patient should continue wearing the brace and have a repeat CT at 6 months from the time of diagnosis. Weaning from the brace when bony healing has occurred should be done over a 6 month period. It is recommended that standing lateral films be obtained at 6, 12, and 24 months from diagnosis to assess for spondylolisthesis. If bony healing does not occur a trial using a bone stimulator may be attempted and follow up with standing lateral films should be done every 3 months to evaluate for spondylolisthesis. Spondylolisthesis of greater than 50% should be sent for surgical stabilization [1].

Due to the current lack of prospective data on management of bilateral spondylolysis, the treatment plan includes counseling patients regarding different treatment options and duration of therapy. The patient should be aware of possible untoward outcomes such as degenerative changes, spondylolisthesis, and pain. Both the patient and physician need to be comfortable with the final therapeutic strategy.

This case suggests acute bilateral pars interarticularis lesions can achieve bony healing with conservative management and prolonged bracing. Future prospective studies need to be conducted to further differentiate the most suitable treatment method for acute bilateral spondylolysis visualized on bone scan. These studies should evaluate strengthening, flexibility, bracing, and return to activity.


1. McTimoney M, Micheli L: Current evaluation and management of spondylolysis and spondylolisthesis.Curr Sports Med Rep 2003, 2:41–46.
2. Herman M, Pizzutillo P, Cavalier R: Spondylolysis and spondylolisthesis in the child and adolescent athlete.Orthop Clin North Am 2003, 34:461–467.
3. Miller S, Congeni J, Swanson K: Long-term functional and anatomical follow-up of early detected spondylolysis in young athletes.Am J Sports Med 2004, 32:928–933.
4. Sys J, Michielsen J, Bracke P, et al.: Nonoperative treatment of active spondylolysis in elite athletes with normal x-ray findings: literature review and results of conservative treatment.Eur Spine J 2001, 10:498–504.
5. Eck J, Riley L: Return to play after lumbar spine conditions and surgeries.Clin Sports Med 2004, 23:367.
© 2005 American College of Sports Medicine